Sample records for efficient crust heating

  1. Identification of radiogenic heat source distribution in the crust: A ...

    Indian Academy of Sciences (India)

    Radiogenic heat sources present in the continental crust contribute significantly to the total surface heat flow and temperature distribution in the crust. Various modelsforthe depth distribution of radiogenic sources have been proposed. Among these modelsthe exponential model has been shown to be an optimal, smooth ...

  2. Identification of radiogenic heat source distribution in the crust: A ...

    Indian Academy of Sciences (India)

    optimal, smooth model through the variational approach applied to the heat conduction equation. ... an additional term is an optimal model for the radiogenic heat source distribution in this case also. They treated the crust as .... Burghes D, Graham A 1980 Introduction to control theory including optimal control. Mathematics.

  3. Heat production distributions and the geochemical self-organization of the crust (United States)

    Sandiford, M.


    The distribution of the heat producing elements within the lithosphere provides an important control on continental thermal regimes and the mechanical strength of the lithosphere. Moreover, the strong temperature-dependence of lithospheric rheology suggests the possibility of an important feedback between tectonic processes, such as metamorphism, deformation and magmatism, and the distribution of heat producing elements. Simple models for lithospheric rheology are used to illustrate how such feedback might serve as an important control on both the characteristic abundance of, and spatial variation in, the heat production elements in the crust. These models also imply that the organization of heat producing elements is essential for the long-term tectonic stabilisation of the continental crust. This is particularly relevant to evolution of cratons in early Earth history, wherein lies the most dramatic evidence for the role played by tectonic processes in achieving a stable ordering of the heat producing elements, consistent with the crust as a self-organizing geochemical system.

  4. Nuclear Superfluidity and Specific Heat in the Inner Crust of Neutron Stars


    Sandulescu, N.


    We analyse the temperature dependence of pairing correlations in the inner crust matter of neutron stars. The study is done in a finite-temperature HFB approach and by using a zero range pairing force adjusted to the pairing properties of infinite neutron matter. Within the same approach we investigate how the specific heat of the inner crust depends on temperature, matter inhomogeneity, and the assumption used for the pairing force. It is shown that in a physical relevant range of densities ...

  5. Entropy-information perspective to radiogenic heat distribution in continental crust

    Directory of Open Access Journals (Sweden)

    R. N. Singh


    Full Text Available Depth distribution of radiogenic heat sources in continental crust is an important parameter that controls its thermal structure as well as the mantle heat flow at the base of continental lithosphere. Various models for the depth distribution of radiogenic heat sources have been proposed. Starting from constant and exponential models based on linear heat flow–heat generation relationship the present-day layered models integrate crustal structure and laboratory measurements of radiogenic heat sources in various exposed rocks representing crustal composition. In the present work, an extended entropy theory formalism is used for estimation of radiogenic heat sources distribution in continental crust based on principle of maximum entropy (POME. The extended entropy principle yields a constant heat generation model if only a constraint given by total radiogenic heat in the crust is used and an exponential form of radiogenic heat sources distribution if an additional constraint in the form of a second moment is used in the minimization of entropy.

  6. Heat Flow Variation along the Nankai Trough Floor Correlated with the Structure of the Shikoku Basin Oceanic Crust (United States)

    Yamano, M.; Kawada, Y.; Gao, X.


    Surface heat flow observed on the floor of the Nankai Trough, near the trench axis, is highly variable and does not well correspond to the seafloor age of the incoming Philippine Sea plate (Shikoku Basin). Recent detailed measurements between 133.5°E and 137°E revealed that heat flow on the trough floor significantly varies along the trough. The most conspicuous variation is found around 136°E. Heat flow is extremely high and variable between 135°E and 136°E, much higher than the value estimated from the age. On the east of 136°E, heat flow gradually decreases eastward over 50 km to the value nearly consistent with the age with no appreciable scatter. Elevated heat flow on the trough floor can be attributed to vigorous fluid circulation in a permeable layer (aquifer) in the subducted oceanic crust, which efficiently transports heat upward along the plate interface (Spinelli and Wang, 2008). The heat flow variation around 136°E may therefore arise from variation in the permeability structure of the crustal aquifer. A probable cause of the heterogeneity in the aquifer permeability is a structure boundary in the incoming Shikoku Basin, the boundary between the younger part on the west formed by spreading in NE-SW direction and the older part on the east formed by E-W spreading. It is located around 136°E, about the same place as the heat flow distribution boundary. A possible additional source of variation in the permeability structure is the geometry of the subducted Philippine Sea plate. A prominent bend in the subducted plate between 135°E and 136°E, which corresponds to the high heat flow area on the trough floor, may have fractured the oceanic crust and enhanced the aquifer permeability. We evaluated the influence of variations in the aquifer permeability on the thermal structure through 3D numerical modelling using a high thermal-conductivity proxy for heat transport by fluid flow. A sharp along-strike change in the permeability of the subducted

  7. Energy efficient ammonia heat pump. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Claus; Pijnenburg, B.; Schumann Grindorf, H. [Danish Technological Institute, Aarhus (Denmark); Christensen, Rolf [Alfa Laval, Lund (Sweden); Rasmussen, Bjarne D. [Grundfos, Bjerringbro (Denmark); Gram, S.; Fredborg Jakobsen, D. [Svedan Industri Koeleanlaeg, Greve (Denmark)


    The report describes the development of a highly effective ammonia heat pump. Heat pumps play an increasingly important role in the search for more effective use of energy in our society. Highly efficient heat pumps can contribute to reduced energy consumption and improved economy of the systems which they are a part of. An ammonia heat pump with high pressure reciprocating compressor and a novel split condenser was developed to prove potential for efficiency optimization. The split of the condenser in two parts can be utilized to obtain smaller temperature approaches and, thereby, improved heat pump efficiency at an equal heat exchanger area, when compared to the traditional solution with separate condenser and de-superheater. The split condenser design can also be exploited for heating a significant share of the total heating capacity to a temperature far above the condensing temperature. Furthermore, the prototype heat pump was equipped with a plate type evaporator combined with a U-turn separator with a minimum liquid height and a liquid pump with the purpose of creating optimum liquid circulation ratio for the highest possible heat transfer coefficients at the lowest possible pressure drop. The test results successfully confirmed the highest possible efficiency; a COP of 4.3 was obtained when heating water from 40 deg. C to 80 deg. C while operating with evaporating/condensing temperatures of +20 deg C/+73 deg C. (Author)

  8. Large Efficient Intelligent Heating Relay Station System (United States)

    Wu, C. Z.; Wei, X. G.; Wu, M. Q.


    The design of large efficient intelligent heating relay station system aims at the improvement of the existing heating system in our country, such as low heating efficiency, waste of energy and serious pollution, and the control still depends on the artificial problem. In this design, we first improve the existing plate heat exchanger. Secondly, the ATM89C51 is used to control the whole system and realize the intelligent control. The detection part is using the PT100 temperature sensor, pressure sensor, turbine flowmeter, heating temperature, detection of user end liquid flow, hydraulic, and real-time feedback, feedback signal to the microcontroller through the heating for users to adjust, realize the whole system more efficient, intelligent and energy-saving.

  9. Energy efficiency of electrical infrared heating elements

    International Nuclear Information System (INIS)

    Brown, K.J.; Farrelly, R.; O’Shaughnessy, S.M.; Robinson, A.J.


    Highlights: • Characterization of the radiant energy efficiency of infrared heating elements. • Performed for a commercially available ceramic heater element for two cases. • Total radiant power and net radiant efficiency is computed. • Radiant efficiencies are strongly dependant on the input power to the element. • In-plane efficiencies depend on the distance from the heater. - Abstract: A measurement system has been designed to characterize the radiant energy efficiency of infrared heating elements. The system also allows for measurement of the radiant heat flux distribution emitted from radiant heater assemblies. To facilitate these, a 6-axis robotic arm is fitted with a Schmidt–Boelter radiant heat flux gauge. A LabVIEW interface operates the robot and positions the sensor in the desired location and subsequently acquires the desired radiant heat flux measurement. To illustrate the functionality of the measurement system and methodology, radiant heat flux distributions and efficiency calculations are performed for a commercially available ceramic heater element for two cases. In the first, a spherical surface is traced around the entire heater assembly and the total radiant power and net radiant efficiency is computed. In the second, 50 cm × 50 cm vertical planes are traced parallel to the front face of the heater assembly at distances between 10 cm and 50 cm and the in-plane power and efficiencies are computed. The results indicate that the radiant efficiencies are strongly dependant on the input power to the element and, for the in-plane efficiencies, depend on the distance from the heater.


    Directory of Open Access Journals (Sweden)

    Valeriu Dragan


    and manner under which the efficiency itself is calculated. The paper  presents a more robust approach to measuring efficiency, regardless of the heat transfer within the turbomachinery itself. Possible applications of the study may range from cold-start regime simulation to the optimization of inter-cooling setup or even flow angle control without mechanically actuated OGV

  11. The research of heating efficiency of different induction heating systems

    Directory of Open Access Journals (Sweden)

    Konesev Sergey


    Full Text Available Computer models of tape and coil inductors are described, and a comparison of the heating efficiency depending on various parameters is made. The developed computer model was made in the ELCUT 6.0. As a result of the simulation, data on the heating characteristics (depending on the various parameters of the heating elements are obtained. The average statistical data of a series of experiments with a tape inductor are given. It is shown that for the same parameters (values of inductance and number of wires, the tape version inductor heats up a pipe to a higher temperature (by 5.08% than the inductor in the coil version in 10 minutes.

  12. Measurement of heat and moisture exchanger efficiency. (United States)

    Chandler, M


    Deciding between a passive heat and moisture exchanger or active humidification depends upon the level of humidification that either will deliver. Published international standards dictate that active humidifiers should deliver a minimum humidity of 33 mg.l(-1); however, no such requirement exists, for heat and moisture exchangers. Anaesthetists instead have to rely on information provided by manufacturers, which may not allow comparison of different devices and their clinical effectiveness. I suggest that measurement of humidification efficiency, being the percentage moisture returned and determined by measuring the temperature of the respired gases, should be mandated, and report a modification of the standard method that will allow this to be easily measured. In this study, different types of heat and moisture exchangers for adults, children and patients with a tracheostomy were tested. Adult and paediatric models lost between 6.5 mg.l(-1) and 8.5 mg.l(-1) moisture (corresponding to an efficiency of around 80%); however, the models designed for patients with a tracheostomy lost between 16 mg.l(-1) and 18 mg.l(-1) (60% efficiency). I propose that all heat and moisture exchangers should be tested in this manner and percentage efficiency reported to allow an informed choice between different types and models. © 2013 The Association of Anaesthetists of Great Britain and Ireland.

  13. Influence of scale deposit and its thickness on the heat exchanger operational efficiency (United States)

    Kocharyan, E. V.; Skiba, E. D.; Levina, E. Y.


    Materials submitted provide for the research results of the problem of scale formation in heat exchangers and show results of calculations of scale type and thickness impact on heat transfer factor and on heat exchanger overall energy efficiency with regard to heat exchanger hydraulic resistance increase. Calculations have been carried out using the example of heat exchanger PV1 (∏B1) 219-2-G-1, 6-6-UZ, manufactured as per State Standard (GOST) 27590-2005. On the basis of calculations performed recommendations on maximum allowable thickness of scale crust of different type, after scaling of which the heat exchanger operation may infringe the technological process, have been elaborated.

  14. Collisional stripping of planetary crusts (United States)

    Carter, Philip J.; Leinhardt, Zoë M.; Elliott, Tim; Stewart, Sarah T.; Walter, Michael J.


    Geochemical studies of planetary accretion and evolution have invoked various degrees of collisional erosion to explain differences in bulk composition between planets and chondrites. Here we undertake a full, dynamical evaluation of 'crustal stripping' during accretion and its key geochemical consequences. Crusts are expected to contain a significant fraction of planetary budgets of incompatible elements, which include the major heat producing nuclides. We present smoothed particle hydrodynamics simulations of collisions between differentiated rocky planetesimals and planetary embryos. We find that the crust is preferentially lost relative to the mantle during impacts, and we have developed a scaling law based on these simulations that approximates the mass of crust that remains in the largest remnant. Using this scaling law and a recent set of N-body simulations of terrestrial planet formation, we have estimated the maximum effect of crustal stripping on incompatible element abundances during the accretion of planetary embryos. We find that on average approximately one third of the initial crust is stripped from embryos as they accrete, which leads to a reduction of ∼20% in the budgets of the heat producing elements if the stripped crust does not reaccrete. Erosion of crusts can lead to non-chondritic ratios of incompatible elements, but the magnitude of this effect depends sensitively on the details of the crust-forming melting process on the planetesimals. The Lu/Hf system is fractionated for a wide range of crustal formation scenarios. Using eucrites (the products of planetesimal silicate melting, thought to represent the crust of Vesta) as a guide to the Lu/Hf of planetesimal crust partially lost during accretion, we predict the Earth could evolve to a superchondritic 176Hf/177Hf (3-5 parts per ten thousand) at present day. Such values are in keeping with compositional estimates of the bulk Earth. Stripping of planetary crusts during accretion can lead to

  15. Heat conversion alternative petrochemical complexes efficiency (United States)

    Mrakin, A. N.; Selivanov, A. A.; Morev, A. A.; Batrakov, P. A.; Kulbyakina, A. V.; Sotnikov, D. G.


    The paper presents the energy and economic efficiency calculation results of the petrochemical complexes based upon the sulfur oil shales processing by solid (ash) heat-carrier low-temperature carbonization plants by Galoter technology. The criterion for such enterprises fuel efficiency determining was developed on the base of the exergy methodology taking into account the recurrent publications consolidation. In this case, in supplying the consumers with paving bitumen, motor benzol, thiophene, toluene, 2-methylthiophene, xylene, gas sulfur, complex thermodynamic effectiveness was founded to amount to 53 %, and if ash residue realization is possible then it was founded to be to 70 %. The project economic attractiveness determining studies depending on the feedstock cost, its delivery way and investments amount changing were conducted.

  16. Density Sorting During the Evolution of Continental Crust (United States)

    Kelemen, P. B.; Behn, M. D.; Hacker, B. R.


    We consider two settings - in addition to "delamination" of arc lower crust - in which dense, mafic eclogites founder into the convecting mantle while buoyant, felsic lithologies accumulate at the base of evolving continental crust. Arc processes play a central role in generating continental crust, but it remains uncertain how basaltic arc crust is transformed to andesitic continental crust. Dense, SiO2-poor products of fractionation may founder from the base of arc crust by "delamination", but lower arc crust after delamination has significantly different trace elements compared to lower continental crust (LCC). In an alternative model, buoyant magmatic rocks generated at arcs are first subducted, mainly via subduction erosion. Upon heating, these buoyant lithologies ascend through the mantle wedge or along a subduction channel, and are "relaminated" at
the base of overlying crust (e.g., Hacker et al EPSL 11, AREPS 15). Average buoyant lavas and plutons
for the Aleutians, Izu-Bonin-Marianas, Kohistan and Talkeetna arcs fall within the range of estimated LCC major and trace elements. Relamination is more efficient in generating continental crust than delamination. Himalayan cross-sections show Indian crust thrust beneath Tibetan crust, with no intervening mantle. There is a horizontal Moho at ca 80 km depth, extending from thickened Indian crust, across the region where Tibetan crust overlies Indian crust, into thickened Tibetan crust. About half the subducted Indian crust is present, whereas the other half is missing. Data (Vp/Vs; Miocene lavas formed by interaction of continental crust with mantle; xenolith thermometry) indicate 1000°C or more from ca 50 km depth to the Moho since the Miocene. We build on earlier studies (LePichon et al Tectonics 92, T'phys 97; Schulte-Pelkum et al Nature 05; Monsalve et al JGR 08) to advance the hypothesis that rapid growth of garnet occurs at 70-80 km and 1000°C within subducting Indian crust. Dense eclogites founder

  17. Heat and Fission Product Transport in a Molten U-Zr-O Pool With Crust

    International Nuclear Information System (INIS)

    Yun, J.I.; Suh, K.Y.; Kang, C.S.


    Heat transfer and fluid flow in a molten pool are influenced by internal volumetric heat generated from the radioactive decay of fission product species retained in the pool. The pool superheat is determined based on the overall energy balance that equates the heat production rate to the heat loss rate. Decay heat of fission products in the pool was estimated by product of the mass concentration and energy conversion factor of each fission product. For the calculation of heat generation rate in the pool, twenty-nine elements were chosen and classified by their chemical properties. The mass concentration of a fission product is obtained from released fraction and the tabular output of the ORIGEN 2 code. The initial core and pool inventories at each time can also be estimated using ORIGEN 2. The released fraction of each fission product is calculated based on the bubble dynamics and mass transport. Numerical analysis was performed for the TMI-2 accident. The pool is assumed to be a partially filled hemispherical geometry and the change of pool geometry during the numerical calculation was neglected. Results of the numerical calculation revealed that the peak temperature of the molten pool significantly decreased and most of the volatile fission products were released from the molten pool during the accident. (authors)

  18. Energy Efficient Waste Heat Recovery from an Engine Exhaust System (United States)


    AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE ENERGY EFFICIENT WASTE HEAT RECOVERY FROM AN ENGINE EXHAUST SYSTEM 5. FUNDING NUMBERS 6...release. Distribution is unlimited. ENERGY EFFICIENT WASTE HEAT RECOVERY FROM AN ENGINE EXHAUST SYSTEM Aaron R. VanDenBerg Lieutenant, United...HEAT RECOVERY DEVICES Ships mainly extract heat and energy from exhaust gases by using a waste heat boiler located in the actual exhaust duct. The

  19. Universal Optimization Efficiency for Nonlinear Irreversible Heat Engines (United States)

    Zhang, Yanchao; Guo, Juncheng; Lin, Guoxing; Chen, Jincan


    We introduce a multi-parameter combined objective function of heat engines under the strong coupling and symmetry condition and derive the universal expression of the optimization efficiency. The results obtained show that the optimization efficiency derived from the multi-parameter combined objective function include a variety of optimization efficiencies, such as the efficiency at the maximum power, efficiency at the maximum efficiency-power state, efficiency at the maximum ecological or unified trade-off function, and Carnot efficiency. It is further explained that these results are also suitable for the endoreversible cycle model of the Carnot heat engines operating between two heat reservoirs.

  20. Environmental and energy efficiency evaluation of residential gas and heat pump heating

    International Nuclear Information System (INIS)

    Ganji, A.R.


    Energy efficiency and source air pollutant emission factors of gas heaters, gas engine heat pumps, and electric heat pumps for domestic heating have been evaluated and compared. The analysis shows that with the present state of technology, gas engine heat pumps have the highest energy efficiency followed by electric heat pumps and then gas heaters. Electric heat pumps produce more than twice as much NO x , and comparable CO 2 and CO per unit of useful heating energy compared to natural gas heaters. CO production per unit of useful heating energy from gas engine heat pumps without any emission control is substantially higher than electric heat pumps and natural gas heaters. NO x production per unit of useful heating energy from natural gas engine heat pumps (using lean burn technology) without any emission control is about the same as effective NO x production from electric heat pumps. Gas engine heat pumps produce about one-half CO 2 compared to electric heat pumps

  1. Increasing the Efficiency of Maple Sap Evaporators with Heat Exchangers (United States)

    Lawrence D. Garrett; Howard Duchacek; Mariafranca Morselli; Frederick M. Laing; Neil K. Huyler; James W. Marvin


    A study of the engineering and economic effects of heat exchangers in conventional maple syrup evaporators indicated that: (1) Efficiency was increased by 15 to 17 percent with heat exchangers; (2) Syrup produced in evaporators with heat exchangers was similar to syrup produced in conventional systems in flavor and in chemical and physical composition; and (3) Heat...

  2. Exergetic efficiency optimization for an irreversible heat pump ...

    Indian Academy of Sciences (India)

    The irreversibilities considered in the system include heat resistance losses in the hot- and cold-side heat exchangers and non-isentropic losses in the compression and expansion processes. The analytical formulas of the heating load, coefficient of performance (COP) and exergetic efficiency for the heat pumps are derived ...

  3. Research of waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water (United States)

    Zhang, Li; Zhang, Yu; Zhou, Liansheng; E, Zhijun; Wang, Kun; Wang, Ziyue; Li, Guohao; Qu, Bin


    The waste heat energy efficiency for absorption heat pump recycling thermal power plant circulating water has been analyzed. After the operation of heat pump, the influences on power generation and heat generation of unit were taken into account. In the light of the characteristics of heat pump in different operation stages, the energy efficiency of heat pump was evaluated comprehensively on both sides of benefits belonging to electricity and benefits belonging to heat, which adopted the method of contrast test. Thus, the reference of energy efficiency for same type projects was provided.

  4. Loop heat pipes - highly efficient heat-transfer devices for systems of sun heat supply

    Energy Technology Data Exchange (ETDEWEB)

    Maydanik, Yu. [Ural Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Thermophysics


    Loop heat pipes (LHPs) are hermetic heat-transfer devices operating on a closed evaporation-condensation cycle with the use of capillary pressure for pumping the working fluid [1]. In accordance with this, they possess all the main advantages of conventional heat pipes, but, as distinct from the latter, have a considerably higher heat-transfer capacity, especially when operating in the ''antigravity'' regime, when heat is transferred from above downwards. Besides, LHPs possess a higher functional versatility, are adaptable to different operating conditions and provide great scope for various design embodiments. This is achieved at the expense of both the original design of the device and the properties of the wick - a special capillary structure used for the creation of capillary pressure. The LHP schematic diagram is given in Fig. 1. The device contains an evaporator and a condenser - heat exchanger connected by means of smooth-walled pipe-lines with a relatively small diameter intended for separate motion of vapor and liquid. At present loop heat pipes are most extensively employed in thermoregulation systems of spacecrafts. Miniature LHPs are used for cooling electronics and computers. At the same time there exists a considerable potential of using these devices for the recovery of low-grade (waste) heat from different sources, and also in systems of sun heat supply. In the latter case LHPs may serve as an efficient heat-transfer link between a sun collector and a heat accumulator, which has a low thermal resistance and does not consume any additional energy for pumping the working fluid between them. (orig.)

  5. Exergetic efficiency optimization for an irreversible heat pump ...

    Indian Academy of Sciences (India)

    This paper deals with the performance analysis and optimization for irreversible heat pumps working on reversed Brayton cycle with constant-temperature heat reservoirs by taking exergetic efficiency as the optimization objective combining exergy concept with finite-time thermodynamics (FTT). Exergetic efficiency is ...

  6. Assessment of impact of borehole heat exchanger design on heat extraction/rejection efficiency

    Directory of Open Access Journals (Sweden)

    Gornov V.F.


    Full Text Available The article considers the impact of design of borehole heat exchanger (BHE as one of the main elements of a geothermal heat pump system on its efficiency in the ground heat extraction/rejection. Four BHE modifications are considered: coaxial with metal and polyethylene outside tube as well as single and double U-shaped structures of polyethylene tubes. Numerical modeling resulted to data on the efficiency of these BHE modifications for rejection heat into ground (heat pump system in cooling mode, and ground heat extraction (heat pump system in heating mode. Numerical values were obtained and BHEs were ranked according to their efficiency in both operation modes. Besides, additional calculations were made for the most common modification - double U-shaped design - in the ground heat extraction mode for various tube sizes with various wall thicknesses.

  7. Efficiency of the heat pump cooperating with various heat sources in monovalent and bivalent systems

    Energy Technology Data Exchange (ETDEWEB)

    Kurpaska, S.; Latala, H. [Krakow Univ. of Agriculture, Krakow (Poland). Inst. of Agricultural Engineering and Computer Science


    This paper reported on a study that tested the efficiency of compressor heat pumps cooperating with various types of lower heat sources such as horizontal ground heat exchangers, vertical exchangers and sources operating in the bivalent system. The system for receiving energy consisted of a traditional heating system and liquid-air exchangers. The study identified a strong relationship between the heating efficiency of the analysed systems and temperature inside the structure. The study showed that the bivalent system was fully capable of meeting a heat requirement of about 1 MJ -2.

  8. Heat pumps; Synergy of high efficiency and low carbon electricity

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Akio


    Heat pump is attracting wide attention for its high efficiency to utilize inexhaustible and renewable ambient heat in the environment. With its rapid innovation and efficiency improvement, this technology has a huge potential to reduce CO2 emissions by replacing currently widespread fossil fuel combustion systems to meet various heat demands from the residential, commercial and industrial sectors. Barriers to deployment such as low public awareness and a relatively long pay-back period do exist, so it is strongly recommended that each country implement policies to promote heat pumps as a renewable energy option and an effective method to combat global warming.

  9. Maximum conversion efficiency of thermionic heat to electricity ...

    African Journals Online (AJOL)

    ... for a Pure Tungsten, W metal surface. The results show that low value of collector voltage is required for a high efficiency; low radiation heat loss is required for a high conversion efficiency and relatively low values of emitter work function are required for maximum conversion efficiency at ordinary emitter temperature.

  10. Modeling of Methods to Control Heat-Consumption Efficiency (United States)

    Tsynaeva, E. A.; Tsynaeva, A. A.


    In this work, consideration has been given to thermophysical processes in automated heat consumption control systems (AHCCSs) of buildings, flow diagrams of these systems, and mathematical models describing the thermophysical processes during the systems' operation; an analysis of adequacy of the mathematical models has been presented. A comparison has been made of the operating efficiency of the systems and the methods to control the efficiency. It has been determined that the operating efficiency of an AHCCS depends on its diagram and the temperature chart of central quality control (CQC) and also on the temperature of a low-grade heat source for the system with a heat pump.

  11. Analyzing the Efficiency of Introduction of the Intermittent Heating Mode (United States)

    Anisimova, E.; Shcherbak, A.


    The efficiency of introduction of an optimal intermittent heating mode for a service center building in Chelyabinsk is estimated. The optimal intermittent heating mode ensures heat energy saving while maintaining the required microclimate parameters. The graphical dependencies of the amount of heat energy saving on the heat retention of the building and the outdoor air temperature are shown. The fundamental formulas which were the basis for calculating the periods of cooling, warming and expenditures of heat energy for the two heating modes are given. The literature on the issue is reviewed, the main points, advantages and disadvantages in the works of both Russian and foreign authors are revealed. The calculation was carried out in compliance with the modern state standards and regulatory documents. The capital costs of a system construction with an intermittent heating mode are determined.

  12. Regenerator heat exchanger – calculation of heat recovery efficiency and pressure loss

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per Kvols

    Performance of heat exchangers is determined based on two main parameters: efficiency to exchange / recover heat and pressure loss due to friction between fluid and exchanger surfaces. These two parameters are contradicting each other which mean that the higher is efficiency the higher becomes...... pressure loss. The aim of the optimized design of heat exchanger is to reach the highest or the required heat efficiency and at the same time to keep pressure losses as low as possible keeping total exchanger size within acceptable size. In this report is presented analytical calculation method...

  13. Impact of heat shock step on bacterial transformation efficiency. (United States)

    Rahimzadeh, Maral; Sadeghizadeh, Majid; Najafi, Farhood; Arab, Seyed; Mobasheri, Hamid


    CaCl 2 treatment followed by heat shock is the most common method for artificial transformation. Here, the cells were transformed using CaCl 2 treatment either with heat shock (standard protocol) or without heat shock (lab protocol) to comprehend the difference in transformation efficiency. The BL21 strain of Escherichia coli ( E. coli ) was being susceptible using CaCl 2 treatment. Some Cells were kept at -80 o C while the others were kept at 4 ˚C. Afterwards the susceptible cells were transformed using either standard or lab protocol. The transformation efficiency between cells experienced heat shock and those were not influenced by heat shock was almost the same. Moreover, regardless of transformation protocol, the cells kept at 4 ˚C were transformed more efficiently in compared to those were kept at -80 o C.

  14. How Efficient is a Laboratory Burner in Heating Water? (United States)

    Jansen, Michael P.


    Describes an experiment in which chemistry students determine the efficiency of a laboratory burner used to heat water. The reaction is assumed to be the complete combustion of methane, CH4. The experiment is appropriate for secondary school chemistry students familiar with heats of reaction and simple calorimetry. Contains pre-laboratory and…

  15. Exergetic efficiency optimization for an irreversible heat pump ...

    Indian Academy of Sciences (India)

    Beijing 100124, People's Republic of China. 2Postgraduate School, Naval University of Engineering, Wuhan 430033, People's Republic of China ..... perature ratio on the dimensionless heat- ing load vs. pressure ratio. Figure 4. Exergetic efficiency and the di- mensionless heating load vs. the COP. Figure 5. Effect of ...

  16. The solar ultraviolet heating efficiency of the midlatitude thermosphere (United States)

    Torr, M. R.; Torr, D. G.; Richards, P. G.


    In this paper we quantify the major channels by which solar UV energy is transferred to the atmosphere, and determine the UV heating efficiency for the thermosphere. Current knowledge of the solar ultraviolet fluxes, thermospheric chemistry and neutral atmosphere is used in a steady state, interhemispheric solution of the ionospheric continuity, momentum and energy equations. The heating efficiency is found to be a strong function of altitude, and peaks near the altitude of maximum EUV deposition at a value of approximately 50%.

  17. Detachment folding of partially molten crust in accretionary orogens: A new magma-enhanced vertical mass and heat transfer mechanism

    Czech Academy of Sciences Publication Activity Database

    Lehmann, J.; Schulmann, K.; Lexa, O.; Závada, Prokop; Štípská, P.; Hasalová, Pavlína; Belyanin, G.; Corsini, M.


    Roč. 9, č. 6 (2017), s. 889-909 ISSN 1941-8264 Institutional support: RVO:67985530 Keywords : continental crust * shear-zone * gneiss domes Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.662, year: 2016

  18. Skopje - energetic efficiency demonstration zone (Macedonia - solar heating)

    International Nuclear Information System (INIS)

    Pop-Jordanov, Jordan; Dimitrov, Dimitar


    The project for energetic efficiency demonstration zone is based on two aspects: increasing the energy efficiency by using photovoltaic systems connected in network and increasing the energy efficiency in the heating systems. Within the SECI (Southeast European Co-operative Initiative), whose aim is to initiate economical and environmental cooperation among the countries in Southeastern Europe, there are six project areas, one of which is being the creation of Energy Efficiency Demonstration Zones Network. For that reason, each SECI member has proposed one energy efficiency demonstration zone. The Macedonian energy efficiency demonstration zone comprises several objects in the Municipality Skopje - Center. (author)


    Directory of Open Access Journals (Sweden)

    A. E. Piir


    Full Text Available  The article shows the calculation comparison of fuel for producing of heat-line water with a help of different technological installations, transforming (converting high-grade heat from burning process of fuel or in the process of non-reversible heat exchange with coolant (heating agent, or with a help of heat engines, which allow to decrease losses of working efficiency and thus to reduce the use of fuel. There were considered five types of plants beginning from the  simplest  one  up  to  the  most  complex  in  two  variants,  when  the  heat  exchangers and machines are perfect (ideal and when equipment has the known degree of efficiency (perfection:1 water-heat boiler station, working on organic fuel;2 electrical boiler station, obtaining energy on power transmission lines from condensing power station;3 line heater of TPP, obtaining steam from heating turbine;4 line heater CPP, powered by steam from pressure reducing unit;5 heat pump, producing energy on power supply lines from TPP.In this article were investigated three ideal reversible ways of transformation of   high- grade heat into low-grade heat with a help of decreasing and increasing and combined (suggested by the authors heat transformers and their thermodynamic equivalence was shown in this article. And there were suggested universal installation for electric energy generation, cold and heat of two grades for heat-water supply and the heating process on the base of gascompressors   gas turbines. These results are so important (actual for power engineers of the countries with  increasing consumption  of organic  fuel and  its enhancement in  value and realizing programs of energy saving .The analysis shows, that the quality of produced low-grade heat per unit of used high-grade heat for ideal plants (installations is: electrical boiler unit – 0.7;  water boiler unit – 1.0; for heat pump, heating turbine, combined heat transformers   – 4

  20. Investigation of Heat Sink Efficiency for Electronic Component Cooling Applications

    DEFF Research Database (Denmark)

    Staliulionis, Ž.; Zhang, Zhe; Pittini, Riccardo


    of relatively simple heat sink application is performed using modeling based on finite element method, and also the potential of such analysis was demonstrated by real-world measurements and comparing obtained results. Thermal modeling was accomplished using finite element analysis software COMSOL and thermo-imaging......Research and optimisation of cooling of electronic components using heat sinks becomes increasingly important in modern industry. Numerical methods with experimental real-world verification are the main tools to evaluate efficiency of heat sinks or heat sink systems. Here the investigation...... camera was used to measure the thermal field distribution. Ideas for future research involving improvement of the experimental setup and modeling verification are given....

  1. High efficiency heat transport and power conversion system for cascade

    International Nuclear Information System (INIS)

    Maya, I.; Bourque, R.F.; Creedon, R.L.; Schultz, K.R.


    The Cascade ICF reactor features a flowing blanket of solid BeO and LiAlO 2 granules with very high temperature capability (up to approx. 2300 K). The authors present here the design of a high temperature granule transport and heat exchange system, and two options for high efficiency power conversion. The centrifugal-throw transport system uses the peripheral speed imparted to the granules by the rotating chamber to effect granule transport and requires no additional equipment. The heat exchanger design is a vacuum heat transfer concept utilizing gravity-induced flow of the granules over ceramic heat exchange surfaces. A reference Brayton power cycle is presented which achieves 55% net efficiency with 1300 K peak helium temperature. A modified Field steam cycle (a hybrid Rankine/Brayton cycle) is presented as an alternate which achieves 56% net efficiency


    Directory of Open Access Journals (Sweden)

    D. Kovalchuk


    Full Text Available The main part of heating systems and domestic hot water systems are based on the natural gas boilers. Forincreasing the overall performance of such heating system the condensation gas boilers was developed and are used. Howevereven such type of boilers don't use all energy which is released from a fuel combustion. The main factors influencing thelowering of overall performance of condensation gas boilers in case of operation in real conditions are considered. Thestructure of the developed mathematical model allowing estimating the overall performance of condensation gas boilers(CGB in the conditions of real operation is considered. Performace evaluation computer experiments of such CGB during aheating season for real weather conditions of two regions of Ukraine was made. Graphic dependences of temperatureconditions and heating system effectiveness change throughout a heating season are given. It was proved that normal CGBdoes not completely use all calorific value of fuel, thus, it isn't effective. It was also proved that the efficiency of such boilerssignificantly changes during a heating season depending on weather conditions and doesn't reach the greatest possible value.The possibility of increasing the efficiency of CGB due to hydraulic division of heating and condensation sections and use ofthe vapor-compression heat pump for deeper cooling of combustion gases and removing of the highest possible amount ofthermal energy from them are considered. The scheme of heat pump connection to the heating system with a convenient gasboiler and the separate condensation economizer allowing to cool combustion gases deeply below a dew point and to warm upthe return heat carrier before a boiler input is provided. The technological diagram of the year-round use of the heat pump forhot water heating after the end of heating season, without gas use is offered.

  3. A criterion to maximize the irreversible efficiency in heat engines

    CERN Document Server

    Aragon-Gonzalez, G; Leon-Galicia, A; Musharrafie-Martinez, M


    The purpose of this work is to obtain a more precise calculation of the effective limits to the efficiency, of several cyclic heat engines. This calculation is based, first, on the equations describing the irreversible efficiency, and second, on a method which results from a general criterion to maximize this efficiency, applicable to several heat engines. With this method, we apply the criterion to maximize efficiencies; establish lower and upper bounds, corresponding to the efficiencies of Curzon-Ahlborn-like and Carnot-like heat engines; and, finally, find analytical or numerical expressions for the efficiencies eta sub m sub e and eta sub m sub a sub x. eta sub m sub a sub x is the maximum irreversible efficiency; eta sub m sub e is the efficiency in which the irreversible efficiency achieves its maximum, in a similar way to the Curzon-Ahlborn efficiency (maximum work or power). The method was applied to a Brayton cycle, presenting internal dissipations of the working fluid and irreversibilities due to th...

  4. Efficient heat dissipation of photonic crystal microcavity by monolayer graphene. (United States)

    Shih, Min-Hsiung; Li, Lain-Jong; Yang, Yi-Chun; Chou, Hsiang-Yu; Lin, Cheng-Te; Su, Ching-Yuan


    Graphene, which exhibits excellent thermal conductivity, is a potential heat dissipation medium for compact optoelectronic devices. Photonic devices normally produce large- quantity of unwanted heat, and thus, a heat dissipation strategy is urgently needed. In this study, single-layer graphene (SLG) grown by chemical vapor deposition (CVD) is used to cover the surface of a photonic crystal (PhC) cavity, where the heat flux produced by the PhC cavity can be efficiently dissipated along the in-plane direction of the SLG. The thermal properties of the graphene-capped PhC cavity were characterized by experiments and theoretical calculations. The thermal resistance of the SLG-capped PhC cavity obtained from experiments is lower than half of that of a bare PhC cavity. The temperature of a SLG-capped PhC cavity is 45 K lower than that without SLG capping under an optical power of 100 μW. Our simulation results indicate that SLG receives the majority of the heat fluxes from the device, leading to the efficient heat dissipation. Both the experimental and simulation results suggest that the SLG is a promising material to enhance the heat dissipation efficiency for optoelectronic applications.

  5. Assessment of two-level heat pump installations’ power efficiency for heat supply systems

    Directory of Open Access Journals (Sweden)

    Аlla Е. Denysova


    Full Text Available The problem of energy saving becomes one of the most important in power engineering. It is caused by exhaustion of world reserves in hydrocarbon fuel, such as gas, oil and coal representing sources of traditional heat supply. Conventional sources has essential shortcomings: low power, ecological and economic efficiencies, that can be eliminated by using alternative methods of power supply, like the considered one: low-temperature natural heat of ground waters of on the basis of heat pump installations application. The heat supply system considered provides an effective use of two-level heat pump installation operating as heat source the Odessa city ground waters during the lowest ambient temperature period. Proposed is a calculation method of heat pump installations on the basis of geothermal heat supply. Calculated are the values of electric energy consumption N by the compressors’ drive, and the heat supply system transformation coefficient µ for a source of geothermal heat from ground waters of Odessa city allowing to estimate efficiency of two-level heat pump installations.

  6. Heat rejection efficiency research of new energy automobile radiators (United States)

    Ma, W. S.; Shen, W. X.; Zhang, L. W.


    The driving system of new energy vehicle has larger heat load than conventional engine. How to ensure the heat dissipation performance of the cooling system is the focus of the design of new energy vehicle thermal management system. In this paper, the heat dissipation efficiency of the radiator of the hybrid electric vehicle is taken as the research object, the heat dissipation efficiency of the radiator of the new energy vehicle is studied through the multi-working-condition enthalpy difference test. In this paper, the test method in the current standard QC/T 468-2010 “automobile radiator” is taken, but not limited to the test conditions specified in the standard, 5 types of automobile radiator are chosen, each of them is tested 20 times in simulated condition of different wind speed and engine inlet temperature. Finally, regression analysis is carried out for the test results, and regression equation describing the relationship of radiator heat dissipation heat dissipation efficiency air side flow rate cooling medium velocity and inlet air temperature is obtained, and the influence rule is systematically discussed.

  7. The influence of heat sink temperature on the seasonal efficiency of shallow geothermal heat pumps (United States)

    Pełka, Grzegorz; Luboń, Wojciech; Sowiżdżał, Anna; Malik, Daniel


    Geothermal heat pumps, also known as ground source heat pumps (GSHP), are the most efficient heating and cooling technology utilized nowadays. In the AGH-UST Educational and Research Laboratory of Renewable Energy Sources and Energy Saving in Miękinia, shallow geothermal heat is utilized for heating. In the article, the seasonal efficiency of two geothermal heat pump systems are described during the 2014/2015 heating season, defined as the period between 1st October 2014 and 30th April 2015. The first system has 10.9 kW heating capacity (according to European Standard EN 14511 B0W35) and extracts heat from three vertical geothermal loops at a depth of 80m each. During the heating season, tests warmed up the buffer to 40°C. The second system has a 17.03 kW heating capacity and extracts heat from three vertical geothermal loops at a depth of 100 m each, and the temperature of the buffer was 50°C. During the entire heating season, the water temperatures of the buffers was constant. Seasonal performance factors were calculated, defined as the quotient of heat delivered by a heat pump to the system and the sum of electricity consumed by the compressor, source pump, sink pump and controller of heat pumps. The measurements and calculations give the following results: - The first system was supplied with 13 857 kWh/a of heat and consumed 3 388 kWh/a electricity. The SPF was 4.09 and the average temperature of outlet water from heat pump was 40.8°C, and the average temperature of brine flows into the evaporator was 3.7 °C; - The second system was supplied with 12 545 kWh/a of heat and consumed 3 874 kWh/a electricity. The SPF was 3.24 and the average temperature of outlet water from heat pump was 51.6°C, and the average temperature of brine flows into the evaporator was 5.3°C. To summarize, the data shown above presents the real SPF of the two systems. It will be significant in helping to predict the SPF of objects which will be equipped with ground source heat pumps.

  8. Size dependence of efficiency at maximum power of heat engine

    KAUST Repository

    Izumida, Y.


    We perform a molecular dynamics computer simulation of a heat engine model to study how the engine size difference affects its performance. Upon tactically increasing the size of the model anisotropically, we determine that there exists an optimum size at which the model attains the maximum power for the shortest working period. This optimum size locates between the ballistic heat transport region and the diffusive heat transport one. We also study the size dependence of the efficiency at the maximum power. Interestingly, we find that the efficiency at the maximum power around the optimum size attains a value that has been proposed as a universal upper bound, and it even begins to exceed the bound as the size further increases. We explain this behavior of the efficiency at maximum power by using a linear response theory for the heat engine operating under a finite working period, which naturally extends the low-dissipation Carnot cycle model [M. Esposito, R. Kawai, K. Lindenberg, C. Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. The theory also shows that the efficiency at the maximum power under an extreme condition may reach the Carnot efficiency in principle.© EDP Sciences Società Italiana di Fisica Springer-Verlag 2013.


    DEFF Research Database (Denmark)

    The 12.5 m² flat plate solar collector HT, today marketed by Arcon Solvarme A/S, has been used in solar heating plants in Scandinavia since 1983. The collector is designed to operate in a temperature interval between 40°C and 90°C. The efficiency of the collector has been strongly improved since...... it was introduced on the market. The paper will present the increase of the efficiency of the collector due to technical improvements since 1983. Further, measurements from the spring of 2009 of the efficiency of two HT collectors, which have been in operation in the solar heating plant Ottrupgaard, Skørping......, Denmark since 1994 with a constant high flow rate and in the solar heating plant Marstal, Denmark since 1996 with a variable flow rate, will be presented. The efficiencies will be compared to the efficiencies of the collectors when they were first installed in the solar heating plants. The measurements...


    DEFF Research Database (Denmark)

    Fan, Jianhua; Chen, Ziqian; Furbo, Simon


    The 12.5 m² flat plate solar collector HT, today marketed by Arcon Solvarme A/S, has been used in solar heating plants in Scandinavia since 1983. The collector is designed to operate in a temperature interval between 40°C and 90°C. The efficiency of the collector has been strongly improved since...... it was introduced on the market. The paper will present the increase of the efficiency of the collector due to technical improvements since 1983. Further, measurements from the spring of 2009 of the efficiency of two HT collectors, which have been in operation in the solar heating plant Ottrupgaard, Skørping......, Denmark since 1994 with a constant high flow rate and in the solar heating plant Marstal, Denmark since 1996 with a variable flow rate, will be presented. The efficiencies will be compared to the efficiencies of the collectors when they were first installed in the solar heating plants. The measurements...

  11. Thermoregulatory efficiency is increased after heat acclimation in tropical natives. (United States)

    Magalhães, Flávio C; Passos, Renata L F; Fonseca, Michele A; Oliveira, Kenya P M; Ferreira-Júnior, João B; Martini, Angelo R P; Lima, Milene R M; Guimarães, Juliana B; Baraúna, Valério G; Silami-Garcia, Emerson; Rodrigues, Luiz O C


    To evaluate the effects of heat acclimation on sweat rate redistribution and thermodynamic parameters, 9 tropical native volunteers were submitted to 11 days of exercise-heat exposures (40+/-0 degrees C and 45.1+/-0.2% relative humidity). Sudomotor function was evaluated by measuring total and local (forehead, chest, arm, forearm, and thigh) sweat rates, local sweat sodium concentration, and mean skin and rectal temperatures. We also calculated heat production (H), heat storage (S), heat exchange by radiation (R) and by convection (C), evaporated sweat (E(sw)), sweating efficiency (eta(sw)), skin wettedness (w(sk)), and the ratio between the heat storage and the sum of heat production and heat gains by radiation and convection (S/(H+R+C)). The heat acclimation increased the whole-body sweat rate and reduced the mean skin temperature. There were changes in the local sweat rate patterns: on the arm, forearm, and thigh it increased significantly from day 1 to day 11 (all p<0.05) and the sweat rates from the forehead and the chest showed a small nonsignificant increase (p=0.34 and 0.17, respectively). The relative increase of local sweat rates on day 11 was not different among the sites; however, when comparing the limbs (arm, forearm, and thigh) with the trunk (forehead and chest), there was a significant higher increase in the limbs (32+/-5%) in comparison to the trunk (11+/-2%, p=0.001). After the heat acclimation period we observed higher w(sk) and E(sw) and reduced S/(H+R+C), meaning greater thermoregulatory efficiency. The increase in the limb sweat rate, but not the increase in the trunk sweat rate, correlated with the increased w(sk), E(sw), and reduced S/(H+R+C) (p<0.05 to all). Altogether, it can be concluded that heat acclimation increased the limbs' sweat rates in tropical natives and that this increase led to increased loss of heat through evaporation of sweat and this higher sweat evaporation was related to higher thermoregulatory efficiency.

  12. Efficiency potential in the district heating sector. Final report

    International Nuclear Information System (INIS)

    Agrell, P.; Bogetoft, P.; Fristrup, P.; Munksgaard, J.; Pade, L.L.


    This report is the final documentation for the research project 'District heating prices in a liberalised energy market - benchmarking the production of combined heat and power'. The project compares activities for almost 300 companies, members of the Danish District Heating Society. The main aim of the analyses has been to uncover the saving potential by comparing each individual company to the most efficient companies in the sector. The variable costs have been studied, amounting to almost 7 billion Danish kroner a year, and the analyses found saving potential ranging from 5% to 60% dependent on the expectations to flexibility assigned to the individual companies. The data used are not available for the public as they exceed the Danish District Heating Society's annual statistics. (BA)

  13. Optimal power and efficiency of quantum Stirling heat engines (United States)

    Yin, Yong; Chen, Lingen; Wu, Feng


    A quantum Stirling heat engine model is established in this paper in which imperfect regeneration and heat leakage are considered. A single particle which contained in a one-dimensional infinite potential well is studied, and the system consists of countless replicas. Each particle is confined in its own potential well, whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions. Based on the Schrödinger equation, the expressions of power output and efficiency for the engine are obtained. Effects of imperfect regeneration and heat leakage on the optimal performance are discussed. The optimal performance region and the optimal values of important parameters of the engine cycle are obtained. The results obtained can provide some guidelines for the design of a quantum Stirling heat engine.

  14. Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers. (United States)

    Tu, Y D; Wang, R Z; Ge, T S; Zheng, X


    Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8-3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump's efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications.

  15. Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers (United States)

    Tu, Y. D.; Wang, R. Z.; Ge, T. S.; Zheng, X.


    Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8–3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump’s efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications. PMID:28079171

  16. Vacuum boilers developed heating surfaces technic and economic efficiency evaluation (United States)

    Slobodina, E. N.; Mikhailov, A. G.; Semenov, B. A.


    The vacuum boilers as manufacturing proto types application analysis was carried out, the possible directions for the heating surfaces development are identified with a view to improving the energy efficiency. Economic characteristics to evaluate the vacuum boilers application efficiency (Net Discounted Income (NDI), Internal Rate of Return (IRR), Profitability Index (PI) and Payback Period) are represented. The given type boilers application technic and economic efficiency criteria were established. NDI changing curves depending on the finning coefficient and operating pressure were obtained as a result of the conducted calculation studies.

  17. Technology Roadmaps: Energy-efficient Buildings: Heating and Cooling Equipment

    Energy Technology Data Exchange (ETDEWEB)



    Buildings account for almost a third of final energy consumption globally and are an equally important source of CO2 emissions. Currently, both space heating and cooling as well as hot water are estimated to account for roughly half of global energy consumption in buildings. Energy-efficient and low/zero-carbon heating and cooling technologies for buildings have the potential to reduce CO2 emissions by up to 2 gigatonnes (Gt) and save 710 million tonnes oil equivalent (Mtoe) of energy by 2050. Most of these technologies -- which include solar thermal, combined heat and power (CHP), heat pumps and thermal energy storage -- are commercially available today. The Energy-Efficient Buildings: Heating and Cooling Equipment Roadmap sets out a detailed pathway for the evolution and deployment of the key underlying technologies. It finds that urgent action is required if the building stock of the future is to consume less energy and result in lower CO2 emissions. The roadmap concludes with a set of near-term actions that stakeholders will need to take to achieve the roadmap's vision.

  18. On the efficiency of solar heating in the middle atmosphere (United States)

    Mlynczak, Martin G.; Solomon, Susan


    The efficiency at which solar ultraviolet radiation absorbed in the Hartley band of ozone is directly converted to heat in the terrestrial mesosphere and lower thermosphere (50-110 km) is calculated. The ozone molecule undergoes photolysis to yield the excited species O(1D) and O2(1Delta) with a quantum yield of about 0.9. Spontaneous emission from O2(1Delta) and from O2(1Sigma) (excited by energy transfer from O/1D/) significantly decreases the amount of energy available for heat. Similarly, the efficiency at which solar ultraviolet radiation absorbed by O2 in the Schumann-Runge continuum is directly converted to heat in the lower thermosphere (95-110 km) is calculated. The O2 undergoes photolysis and the excited product O(1D) is generated. Spontaneous emission from O2(1Sigma) (excited by energy transfer from O/1D/) reduces the amount of energy available for heat in the lower thermosphere. The consideration of these energy transfer and loss processes results in significantly reduced heating rates as compared to those conventionally calculated in models of the middle atmosphere.

  19. Heat exchanger efficiently operable alternatively as evaporator or condenser (United States)

    Ecker, Amir L.


    A heat exchanger adapted for efficient operation alternatively as evaporator or condenser and characterized by flexible outer tube having a plurality of inner conduits and check valves sealingly disposed within the outer tube and connected with respective inlet and outlet master flow conduits and configured so as to define a parallel flow path for a first fluid such as a refrigerant when flowed in one direction and to define a serpentine and series flow path for the first fluid when flowed in the opposite direction. The flexible outer tube has a heat exchange fluid, such as water, flowed therethrough by way of suitable inlet and outlet connections. The inner conduits and check valves form a package that is twistable so as to define a spiral annular flow path within the flexible outer tube for the heat exchange fluid. The inner conduits have thin walls of highly efficient heat transfer material for transferring heat between the first and second fluids. Also disclosed are specific materials and configurations.

  20. An investigation of energy efficient and sustainable heating systems for buildings : Combining photovoltaics with heat pump


    Hesaraki, Arefeh; Holmberg, Sture


    Renewable energy sources contribute considerable amounts of energy when natural phenomena are converted into useful forms of energy. Solar energy, i.e. renewable energy, is converted to electricity by photovoltaic systems (PV). This study was aimed at investigating the possibility of combining PV with Heat Pump (HP) (PV-HP system). HP uses direct electricity to produce heat. In order to increase the sustainability and efficiency of the system, the required electricity for the HP was supposed ...

  1. Crusts: biological (United States)

    Belnap, Jayne; Elias, Scott A.


    Biological soil crusts, a community of cyanobacteria, lichens, mosses, and fungi, are an essential part of dryland ecosystems. They are critical in the stabilization of soils, protecting them from wind and water erosion. Similarly, these soil surface communities also stabilized soils on early Earth, allowing vascular plants to establish. They contribute nitrogen and carbon to otherwise relatively infertile dryland soils, and have a strong influence on hydrologic cycles. Their presence can also influence vascular plant establishment and nutrition.

  2. Energetic Efficiency Evaluation by Using GroundWater Heat Pumps

    Directory of Open Access Journals (Sweden)

    Tokar Adriana


    Full Text Available Romania has significant energy potential from renewable sources, but the potential used is much lower due to technical and functional disadvantages, to economic efficiency, the cost elements and environmental limitations. However, efforts are being made to integrate renewable energy in the national energy system. To promote and encourage private investments for renewable energy utilization, programs have been created in order to access funds needed to implement these technologies. Assessment of such investments was carried out from technical and economical point of view, by analyzing a heat pump using as heat source the solar energy from the ground.

  3. Energy Efficient Clothes Dryer with IR Heating and Electrostatic Precipitator

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Stanton [GE Global Research, Niskayuna, NY (United States)


    The project goal was to develop a revolutionary energy saving technology for residential clothes drying. The team developed an IR (infrared) heating system and NESP (Nebulizer and Electro-Static Precipitator) for integration into a ventless clothes dryer. The proposed technology addresses two of the major inefficiencies in current electric vented dryers by providing effective energy transfer for the removal of the water and recapture of the vapor latent heat. The IR heaters operating in the mid wave (2.5-10um) are very efficient as they target the 3-micron peak absorption of the water molecule. This allows direct energy absorption, unlike conventional element heaters where heat is transferred by convection. The low power NESP removes water vapor from the exhausted stream and recaptures the latent heat in the ESP (Electro-Static Precipitator) exchanger section. This allows the warm dry air to be recirculated back into the drum for additional efficiency savings. The remaining majority of the dryer hardware stays the same. Summing the efficiency gain from the two subcomponents we anticipated the EF (Efficiency Factor) to exceed the goal of 4.04. EF is obtained by dividing the weight (lbs) of water removed by the energy (kWhr) used, where the test load size is 8.45 lbs of bone dry clothing wetted to 57.5% or 4.8lbs of water, and dried to a remaining moisture content of 2.5-5%. Additional benefits include not having to recondition (heat or cool) the large amounts of make-up air to replace the air exhausted by a vented dryer. It was anticipated that the NESP/heat exchanger would be the most challenging and highest risk element in the program. Therefore, the team focused their efforts during Phase 1 of the program on the design, construction, testing, and optimization of the NESP/heat exchanger. At the end Phase 1, the team compared the performance of the NESP/heat exchanger with the system level requirements and made a Go/No-Go decision on proceeding with the second

  4. Investigation of Heat Exchange Efficiency in the Heat Exchanger Waste Heat Recovery with Granular Nozzle

    Directory of Open Access Journals (Sweden)

    Boshkova I.L.


    Full Text Available The article analyzes the characteristics of the heat transfer process between the dispersed and gaseous medium for the moving and fixed layer of particulate material. The methods of calculus of thermal and hydraulic regimes of heat exchangers with a dense layer of particles were elaborated. The results of experimental studies of the process of heating of different kinds of granular material, intended for use as a nozzle in the recuperative heat exchanger. The influence of the height of heating chamber, the particle diameter on the output temperature of the granular material has been determined. The dependence of the temperature of the gas and solid components of the height of the nozzle has been presented.

  5. The computational optimization of heat exchange efficiency in stack chimneys

    Energy Technology Data Exchange (ETDEWEB)

    Van Goch, T.A.J.


    For many industrial processes, the chimney is the final step before hot fumes, with high thermal energy content, are discharged into the atmosphere. Tapping into this energy and utilizing it for heating or cooling applications, could improve sustainability, efficiency and/or reduce operational costs. Alternatively, an unused chimney, like the monumental chimney at the Eindhoven University of Technology, could serve as an 'energy channeler' once more; it can enhance free cooling by exploiting the stack effect. This study aims to identify design parameters that influence annual heat exchange in such stack chimney applications and optimize these parameters for specific scenarios to maximize the performance. Performance is defined by annual heat exchange, system efficiency and costs. The energy required for the water pump as compared to the energy exchanged, defines the system efficiency, which is expressed in an efficiency coefficient (EC). This study is an example of applying building performance simulation (BPS) tools for decision support in the early phase of the design process. In this study, BPS tools are used to provide design guidance, performance evaluation and optimization. A general method for optimization of simulation models will be studied, and applied in two case studies with different applications (heating/cooling), namely; (1) CERES case: 'Eindhoven University of Technology monumental stack chimney equipped with a heat exchanger, rejects heat to load the cold source of the aquifer system on the campus of the university and/or provides free cooling to the CERES building'; and (2) Industrial case: 'Heat exchanger in an industrial stack chimney, which recoups heat for use in e.g. absorption cooling'. The main research question, addressing the concerns of both cases, is expressed as follows: 'what is the optimal set of design parameters so heat exchange in stack chimneys is optimized annually for the cases in which a

  6. Efficiency of utilization of heat of moisture from exhaust gases of heat HRSG of CCGT

    Directory of Open Access Journals (Sweden)

    Galashov Nikolay


    Full Text Available The paper discusses the technology of utilizing the heat of exhaust gas moisture from heat recovery steam gases (HRSG of combined-cycle gas turbine (CCGT. Particular attention focused on the influence of the excess air factor on the trapping of the moisture of the exhaust gases, as in the HRSG of the CCGT its value varies over a wider range than in the steam boilers of the TPP. For the research, has been developed a mathematical model that allows to determine the volumes of combustion products and the amount of water vapor produced according to a given composition of the burned gas and determine the amount of moisture that will be obtained as a result of condensation at a given temperature of the flue gases at the outlet of the condensation heat exchanger (CHE. To calculate the efficiency of the HRSG taking into account the heat of condensation of moisture in the CHE an equation is derived.

  7. Efficient numerical method for district heating system hydraulics

    International Nuclear Information System (INIS)

    Stevanovic, Vladimir D.; Prica, Sanja; Maslovaric, Blazenka; Zivkovic, Branislav; Nikodijevic, Srdjan


    An efficient method for numerical simulation and analyses of the steady state hydraulics of complex pipeline networks is presented. It is based on the loop model of the network and the method of square roots for solving the system of linear equations. The procedure is presented in the comprehensive mathematical form that could be straightforwardly programmed into a computer code. An application of the method to energy efficiency analyses of a real complex district heating system is demonstrated. The obtained results show a potential for electricity savings in pumps operation. It is shown that the method is considerably more effective than the standard Hardy Cross method still widely used in engineering practice. Because of the ease of implementation and high efficiency, the method presented in this paper is recommended for hydraulic steady state calculations of complex networks

  8. Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling (United States)

    Li, Kuang-Hui; Alotaibi, Hamad S.; Sun, Haiding; Lin, Ronghui; Guo, Wenzhe; Torres-Castanedo, Carlos G.; Liu, Kaikai; Valdes-Galán, Sergio; Li, Xiaohang


    In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

  9. Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

    KAUST Repository

    Li, Kuang-Hui


    In a conventional induction-heating III-nitride metalorganic chemical vapor deposition (MOCVD) reactor, the induction coil is outside the chamber. Therefore, the magnetic field does not couple with the susceptor well, leading to compromised heating efficiency and harmful coupling with the gas inlet and thus possible overheating. Hence, the gas inlet has to be at a minimum distance away from the susceptor. Because of the elongated flow path, premature reactions can be more severe, particularly between Al- and B-containing precursors and NH3. Here, we propose a structure that can significantly improve the heating efficiency and allow the gas inlet to be closer to the susceptor. Specifically, the induction coil is designed to surround the vertical cylinder of a T-shaped susceptor comprising the cylinder and a top horizontal plate holding the wafer substrate within the reactor. Therefore, the cylinder coupled most magnetic field to serve as the thermal source for the plate. Furthermore, the plate can block and thus significantly reduce the uncoupled magnetic field above the susceptor, thereby allowing the gas inlet to be closer. The results show approximately 140% and 2.6 times increase in the heating and susceptor coupling efficiencies, respectively, as well as a 90% reduction in the harmful magnetic flux on the gas inlet.

  10. Factors Influencing the Thermal Efficiency of Horizontal Ground Heat Exchangers

    Directory of Open Access Journals (Sweden)

    Eloisa Di Sipio


    Full Text Available The performance of very shallow geothermal systems (VSGs, interesting the first 2 m of depth from ground level, is strongly correlated to the kind of sediment locally available. These systems are attractive due to their low installation costs, less legal constraints, easy maintenance and possibility for technical improvements. The Improving Thermal Efficiency of horizontal ground heat exchangers Project (ITER aims to understand how to enhance the heat transfer of the sediments surrounding the pipes and to depict the VSGs behavior in extreme thermal situations. In this regard, five helices were installed horizontally surrounded by five different backfilling materials under the same climatic conditions and tested under different operation modes. The field test monitoring concerned: (a monthly measurement of thermal conductivity and moisture content on surface; (b continuous recording of air and ground temperature (inside and outside each helix; (c continuous climatological and ground volumetric water content (VWC data acquisition. The interactions between soils, VSGs, environment and climate are presented here, focusing on the differences and similarities between the behavior of the helix and surrounding material, especially when the heat pump is running in heating mode for a very long time, forcing the ground temperature to drop below 0 °C.

  11. Heat transfer and energy efficiency in infrared paper dryers

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, Magnus


    Infrared (IR) dryers are widely used in the paper industry, mainly in the production of coated paper grades. The thesis deals with various aspects of heat transfer and energy use in infrared heaters and dryers as employed in the paper industry. Both gas-fired and electric IR dryers are considered and compared. The thesis also provides an introduction to infrared heaters and infrared drying, including a review of recent literature in the field. The transport of thermal radiation inside a paper sheet was investigated and different IR dryers were compared in terms of their ability to transfer energy to the internal parts of a paper sheet. Although there were evident differences in the absorption of radiation between gas-fired and electric IR dryers, the distinction was found not to be as important as has generally been believed. The main differences appeared to be due to the choice of a one- or a two-sided dryer solution, rather than the spectral distributions emitted by the dryers. A method for evaluating the radiation efficiency of IR heaters was proposed. An electric IR heater was evaluated in the laboratory. The radiation efficiency of the heater was shown to be strongly dependent on the power level. The maximum efficiency, found at high power level, was close to 60 %. A procedure for evaluation of the total energy transfer efficiency of an infrared paper dryer was proposed and used in the evaluation of an electric IR dryer operating in an industrial coating machine. The efficiency of the dryer was roughly 40 %. A model for an electric IR heater was developed. The model includes non-grey radiative heat transfer between the different parts of the heater, as well as conduction in reflector material and convective cooling of the surfaces. Using IR module voltage as the only input, model predictions of temperatures and heat flux were found to agree well with experimental data both at steady state and under transient conditions. The model was also extended to include

  12. Continental crust formation on early Earth controlled by intrusive magmatism. (United States)

    Rozel, A B; Golabek, G J; Jain, C; Tackley, P J; Gerya, T


    The global geodynamic regime of early Earth, which operated before the onset of plate tectonics, remains contentious. As geological and geochemical data suggest hotter Archean mantle temperature and more intense juvenile magmatism than in the present-day Earth, two crust-mantle interaction modes differing in melt eruption efficiency have been proposed: the Io-like heat-pipe tectonics regime dominated by volcanism and the "Plutonic squishy lid" tectonics regime governed by intrusive magmatism, which is thought to apply to the dynamics of Venus. Both tectonics regimes are capable of producing primordial tonalite-trondhjemite-granodiorite (TTG) continental crust but lithospheric geotherms and crust production rates as well as proportions of various TTG compositions differ greatly, which implies that the heat-pipe and Plutonic squishy lid hypotheses can be tested using natural data. Here we investigate the creation of primordial TTG-like continental crust using self-consistent numerical models of global thermochemical convection associated with magmatic processes. We show that the volcanism-dominated heat-pipe tectonics model results in cold crustal geotherms and is not able to produce Earth-like primordial continental crust. In contrast, the Plutonic squishy lid tectonics regime dominated by intrusive magmatism results in hotter crustal geotherms and is capable of reproducing the observed proportions of various TTG rocks. Using a systematic parameter study, we show that the typical modern eruption efficiency of less than 40 per cent leads to the production of the expected amounts of the three main primordial crustal compositions previously reported from field data (low-, medium- and high-pressure TTG). Our study thus suggests that the pre-plate-tectonics Archean Earth operated globally in the Plutonic squishy lid regime rather than in an Io-like heat-pipe regime.

  13. Low Pressure-High Temperature Metamorphism and the Advection of Heat to the Continental Crust: A Case Study from Northwest New Guinea (United States)

    Jost, B.; Webb, M.; White, L. T.


    In northwest New Guinea, Palaeozoic basement rocks forming part of the northern margin of the Australian continent are exposed in a rugged mountain range. This remote and understudied region provides a unique window into the complex Palaeozoic evolution and tectonic history of this region, which we help unravel with new field, petrographic, geochemical, and geochronological data. The basement rocks consist of extensive meta-turbidites that were subject to low pressure-high temperature metamorphism along their eastern margin. They are cross-cut by predominantly acidic granitoids. U-Pb zircon dating reveals that these granitoids intruded in three episodes in the Devonian-Carboniferous, the Carboniferous, and the Triassic. The first episode has not previously been reported in the region. The granitoids are strongly peraluminous, suggesting that partial melting of the meta-sedimentary country rock contributed to their petrogenesis (S-type). The occurrence and character of country rock xenoliths and migmatites supports this interpretation. Equilibrium thermodynamic modelling of the metapelites and the migmatites indicates that a substantial amount of heat was added to the lower and middle crust to cause partial melting and regional metamorphism at relatively low pressure. We propose repeated intrusion of hot magma as the mechanism responsible for advecting the necessary heat from the mantle. This likely occurred in an active continental margin setting during the Devonian-Carboniferous and the Triassic, possibly separated by an interval of magmatic quiescence during most of the Permian. New biostratigraphic and low-temperature thermochronological data reveal very recent Pliocene-Pleistocene uplift and unroofing of these basement rocks.

  14. Estimation of low-potential heat recuperation efficiency of smoke fumes in a condensation heat utilizer under various operation conditions of a boiler and a heating system (United States)

    Ionkin, I. L.; Ragutkin, A. V.; Luning, B.; Zaichenko, M. N.


    For enhancement of the natural gas utilization efficiency in boilers, condensation heat utilizers of low-potential heat, which are constructed based on a contact heat exchanger, can be applied. A schematic of the contact heat exchanger with a humidifier for preheating and humidifying of air supplied in the boiler for combustion is given. Additional low-potential heat in this scheme is utilized for heating of the return delivery water supplied from a heating system. Preheating and humidifying of air supplied for combustion make it possible to use the condensation utilizer for heating of a heat-transfer agent to temperature exceeding the dewpoint temperature of water vapors contained in combustion products. The decision to mount the condensation heat utilizer on the boiler was taken based on the preliminary estimation of the additionally obtained heat. The operation efficiency of the condensation heat utilizer is determined by its structure and operation conditions of the boiler and the heating system. The software was developed for the thermal design of the condensation heat utilizer equipped by the humidifier. Computation investigations of its operation are carried out as a function of various operation parameters of the boiler and the heating system (temperature of the return delivery water and smoke fumes, air excess, air temperature at the inlet and outlet of the condensation heat utilizer, heating and humidifying of air in the humidifier, and portion of the circulating water). The heat recuperation efficiency is estimated for various operation conditions of the boiler and the condensation heat utilizer. Recommendations on the most effective application of the condensation heat utilizer are developed.

  15. High Efficiency RF Heating for Small Nuclear Fusion Rocket Engines, Phase I (United States)

    National Aeronautics and Space Administration — High power nuclear fusion propulsion systems will require high efficiency radio-frequency heating systems in the MHz range for plasma heating. This proposal is for a...

  16. Optimisation of a Swedish district heating system with reduced heat demand due to energy efficiency measures in residential buildings

    International Nuclear Information System (INIS)

    Åberg, M.; Henning, D.


    The development towards more energy efficient buildings, as well as the expansion of district heating (DH) networks, is generally considered to reduce environmental impact. But the combined effect of these two progressions is more controversial. A reduced heat demand (HD) due to higher energy efficiency in buildings might hamper co-production of electricity and DH. In Sweden, co-produced electricity is normally considered to displace electricity from less efficient European condensing power plants. In this study, a potential HD reduction due to energy efficiency measures in the existing building stock in the Swedish city Linköping is calculated. The impact of HD reduction on heat and electricity production in the Linköping DH system is investigated by using the energy system optimisation model MODEST. Energy efficiency measures in buildings reduce seasonal HD variations. Model results show that HD reductions primarily decrease heat-only production. The electricity-to-heat output ratio for the system is increased for HD reductions up to 30%. Local and global CO 2 emissions are reduced. If co-produced electricity replaces electricity from coal-fired condensing power plants, a 20% HD reduction is optimal for decreasing global CO 2 emissions in the analysed DH system. - Highlights: ► A MODEST optimisation model of the Linköping district heating system is used. ► The impact of heat demand reduction on heat and electricity production is examined. ► Model results show that heat demand reductions decrease heat-only production. ► Local and global CO 2 emissions are reduced. ► The system electricity-to-heat output increases for reduced heat demand up to 30%.

  17. Energy sustainable development through energy efficient heating devices and buildings

    International Nuclear Information System (INIS)

    Bojic, M.


    Energy devices and buildings are sustainable if, when they operate, they use sustainable (renewable and refuse) energy and generate nega-energy. This paper covers three research examples of this type of sustainability: (1) use of air-to-earth heat exchangers, (2) computer control of heating and cooling of the building (via heat pumps and heat-recovery devices), and (3) design control of energy consumption in a house. (author)

  18. Impact of Microgroove Shape on Flat Miniature Heat Pipe Efficiency

    Directory of Open Access Journals (Sweden)

    François Ternet


    Full Text Available Miniature heat pipes are considered to be an innovative solution able to dissipate high heat with low working fluid fill charge, provide automatic temperature control, and operate with minimum energy consumption and low noise levels. A theoretical analysis on heat pipe thermal performance using Deionized water or n-pentane as the working fluid has been carried out. Analysis on the maximum heat and capillary limitation is conducted for three microgroove cross sections: rectangular, triangular, and trapezoidal. The effect of microgroove height and width, effective length, trapezoidal microgroove inclination angle, and microgroove shape on heat pipe performance is analysed. Theoretical and experimental investigations of the heat pipes’ heat transport limitations and thermal resistances are conducted.


    Directory of Open Access Journals (Sweden)

    T. A. Ismailov


    Full Text Available Abstract. The necessity to intensify the process of heat transfer in the heat pump is justified. The possibility of heat pumps using for liquid cooling in the engine pipe is shown. The new heat pump design of spiral type with LED ring semiconductor structures, powered by magnetic induction is proposed. The efficiency of LED ring semiconductor structures that operate at low temperatures due to the difference in the levels of energy charges in p- and n-regions isrevealed.The mathematical model for the electrical and thermal parameters calculating of energy-efficient thermoelectric heat pump of the spiral type is developed. The diagram of coolant temperature dependence at the outlet of energy-efficient thermoelectric heat pump of spiral type on the supply current is built. The efficiency of spiral type thermoelectric heat pump application for cooling of the internal combustion engine is proven. 


    Directory of Open Access Journals (Sweden)

    S. S. Belymenko


    Full Text Available Purpose. Development of similarity criteria for different modes of operation of the solid-state heat accumulator working due to accumulation of heat in the volume of the heat storage material without phase transition, and the creation of systematic criteria of heat accumulator efficiency for determination the weight / size parameters and operating modes at the design stage. Methodology. To achieve the objectives of the study the theory of similarity and dimensional analysis were used as well as planning and carrying out techniques of physical experiments. Findings. Based on the theory of similarity and dimensional analysis similarity criteria operation of solid-state heat accumulators, under given basic parameters were obtained. These are performance criteria for charge, discharge and full criterion. Three theorems of similarity theory in application to the solution of engineering problems were used. The criterion of efficiency of the heat accumulator charge characterizes the effectiveness of achieving the specified value of the specific amount of heat in the material of heat accumulator under charge, under received materials, geometrical ratios, and heat flow of the heat input. The efficiency criterion characterizes the discharge efficiency of the heat accumulator, at the accepted materials; mass of heat-retainer and the total accumulated amount of heat when the value of the heat flow and the time of discharge. Full coefficient of the heat accumulator performance characterizes the efficiency of the heat accumulators for a full cycle. Originality. Accordingly to the analysis the implementation of any system of solid-state heat accumulator is possible on the basis of structural schemes of this type of device. The similarity criteria of the efficiency of the charge, the efficiency of discharge and the full criterion of solid-state heat accumulators’ efficiency based on the solid storage material without phase transition were obtained. Practical

  1. Commercial high efficiency dehumidification systems using heat pipes

    Energy Technology Data Exchange (ETDEWEB)


    An improved heat pipe design using separately connected two-section one-way flow heat pipes with internal microgrooves instead of wicks is described. This design is now commercially available for use to increase the dehumidification capacity of air conditioning systems. The design also includes a method of introducing fresh air into buildings while recovering heat and controlling the humidity of the incoming air. Included are applications and case studies, load calculations and technical data, and installation, operation, and maintenance information.

  2. Geothermal heat. Potential, danger, efficiency; Erdwaerme. Potential, Gefahr, Nutzen

    Energy Technology Data Exchange (ETDEWEB)

    Reichel, Wolfgang [Ingenieurbuero Timmer Reichel GmbH, Haan (Germany)


    The author of the contribution under consideration reports on the potential, danger and utilization of geothermal heat. Geothermal heat promises the solution of numerous energy problems. From the use of near-surface layers which substantially are affected by enviromental impacts such as solar radiation up to the depth use of the heat flow from the interior of the earth, there exist very different energy sources which are to be considered separately for each application.

  3. Effects of air velocity and clothing combination on heating efficiency of an electrically heated vest (EHV): a pilot study. (United States)

    Wang, Faming; Gao, Chuansi; Holmér, Ingvar


    Cold endangers the heat balance of the human body. Protective clothing is the natural and most common equipment against cold stress. However, clothing for cold protection may be bulky and heavy, affecting human performance and increasing the work load. In such cases, a heated garment with built-in heating elements may be helpful. This pilot study presents a method based on a thermal manikin to investigate the effects of air velocity and clothing combination on the heating efficiency of an electrically heated vest (EHV). An infrared thermal camera was used to detect surface temperature distributions of the EHV on the front and back. Results show that the heating efficiency of the EHV decreases with increasing air velocity. Changes in EHV sequence in the three-layer clothing combination also significantly affect the heating efficiency: it increases with the increasing number of layers on top of the EHV. The highest mean temperature on the inner surface of the EHV was 40.2 degrees C, which indicates that it is safe for the wearers. For the EHV to heat the human body effectively, we suggest that it be worn as a middle layer. Finally, the EHV is especially suitable for occupational groups whose metabolic rate is below 1.9 Mets.

  4. Thermal efficiency maximization for H- and X-shaped heat exchangers based on constructal theory

    International Nuclear Information System (INIS)

    Chen, Lingen; Feng, Huijun; Xie, Zhihui; Sun, Fengrui


    Constructal optimizations of H- and X-shaped heat exchangers are carried out by taking the maximum thermal efficiency (the ratio of the dimensionless heat transfer rate to the dimensionless total pumping power) as optimization objective. The constraints of total tube volumes and spaces occupied by heat exchangers are considered in the optimizations. For the H-shaped heat exchanger, the thermal efficiency decreases when the dimensionless mass flow rate increases. For the higher order of the X-shaped heat exchanger, when the order number is 3, the thermal efficiency of the heat exchanger with Murry law is increased by 68.54% than that with equal flow velocity in the tubes, and by 435.46% than that with equal cross section area of the tubes. - Highlights: • Constructal optimizations of H- and X-shaped heat exchangers are carried out. • Maximum thermal efficiency is taken as optimization objective. • Thermal efficiency is defined as ratio of heat transfer rate to total pumping power. • Optimal constructs of H- and X-shaped heat exchangers are obtained. • Thermal efficiency of X-shaped heat exchanger is larger than that of H-shaped.

  5. Evaluation of Energy Efficiency Performance of Heated Windows (United States)

    Jammulamadaka, Hari Swarup

    The study about the evaluation of the performance of the heated windows was funded by the WVU Research Office as a technical assistance award at the 2014 TransTech Energy Business Development Conference to the Green Heated Glass company/project owned by Frank Dlubak. The award supports a WVU researcher to conduct a project important for commercialization. This project was awarded to the WVU Industrial Assessment Center in 2015. The current study attempted to evaluate the performance of the heated windows by developing an experimental setup to test the window at various temperatures by varying the current input to the window. The heated double pane window was installed in an insulated box. A temperature gradient was developed across the window by cooling one side of the window using gel based ice packs. The other face of the window was heated by passing current at different wattages through the window. The temperature of the inside and outside panes, current and voltage input, room and box temperature were recorded, and used to calculate the apparent R-value of the window when not being heated vs when being heated. It has been concluded from the study that the heated double pane window is more effective in reducing heat losses by as much as 50% than a non-heated double pane window, if the window temperature is maintained close to the room temperature. If the temperature of the window is much higher than the room temperature, the losses through the window appear to increase beyond that of a non-heated counterpart. The issues encountered during the current round of experiments are noted, and recommendations provided for future studies.


    Directory of Open Access Journals (Sweden)

    Juravleov A.A.


    Full Text Available The work is dedicated to the calculus of the efficiency of the use of heat pumps on the CHP plants. There are presented the interdependences between the pay-back period and NPV of heat pump and the price of 1 kWt of thermal power of heat pump and of the tariff of electricity.

  7. 76 FR 63211 - Energy Efficiency Program: Test Procedures for Residential Water Heaters, Direct Heating... (United States)


    ... Efficiency Program: Test Procedures for Residential Water Heaters, Direct Heating Equipment, and Pool Heaters... residential water heaters, direct heating equipment, and pool heaters. This rulemaking is intended to fulfill... water heaters, possible clarifications and improvement of the direct heating equipment test procedures...

  8. Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency (United States)


    FINAL REPORT Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency ESTCP Project EW-201013 NOVEMBER 2016 Ronald...TITLE AND SUBTITLE Final Report. Subsurface Thermal Energy Storage for Improved 5a. CONTRACT NUMBER 10-C-0027-A Air Conditioning...This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency


    Directory of Open Access Journals (Sweden)

    Maximuk E.P.


    Full Text Available Methods to rise the efficiency of fuel using at town heat and power stations are discussed in detail. It is shown that application of hot water/exhaust absorption chillers allow to use heat energy surplus especially in warm season. As the results, the consumption of heat energy from the power stations is more constant during the year, the efficiency of fuel using is higher, and economics is better. Different technological schemes are discussed in detail.

  10. Field Measurements of Heating Efficiency of Electric Forced-Air Furnaces in Six Manufactured Homes.

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Bob; Palmiter, Larry S.; Siegel, Jeff


    This report presents the results of field measurements of heating efficiency for six manufactured homes in the Pacific Northwest heated with electric forced-air systems. This is the first in a series of regional and national efforts to measure in detail the heating efficiency of manufactured homes. Only six homes were included in this study because of budgetary constraints; therefore this is not a representative sample. These investigations do provide some useful information on the heating efficiency of these homes. Useful comparisons can be drawn between these study homes and site-built heating efficiencies measured with a similar protocol. The protocol used to test these homes is very similar to another Ecotope protocol used in the study conducted in 1992 and 1993 for the Bonneville Power Administration to test the heating efficiency of 24 homes. This protocol combined real-time power measurements of furnace energy usage with energy usage during co-heat periods. Accessory data such as house and duct tightness measurements and tracer gas measurements were used to describe these homes and their heating system efficiency. Ensuring that manufactured housing is constructed in an energy and resource efficient manner is of increasing concern to manufactured home builders and consumers. No comparable work has been done to measure the heating system efficiency of MCS manufactured homes, although some co-heat tests have been performed on manufactured homes heated with natural gas to validate HUD thermal standards. It is expected that later in 1994 more research of this kind will be conducted, and perhaps a less costly and less time-consuming method for testing efficiencies will be develops.

  11. Analysis of directional radiative behavior and heating efficiency for a gas-fired radiant burner

    International Nuclear Information System (INIS)

    Li, B.X.; Lu, Y.P.; Liu, L.H.; Kudo, K.; Tan, H.P.


    For the purpose of energy conservation and uniform heating of object surface, a gas-fired porous radiant burner with a bundle of reflecting tubes is developed. A physical model is developed to simulate the directional radiative behavior of this heating device, in which the Monte Carlo method based on the concept of radiation distribution factor is used to compute the directional radiative behavior. The effects of relating parameters on the directional behavior of radiative heating and the heating efficiency are analyzed. With the increase of the length-to-radius ratio of tube, the radiation heating efficiency decreases, but the radiation energy incident on the object surface is more collimated. The radiation heating efficiency increases with the specular reflectivity. With the increase in length of tube segment with specular reflective surface, the radiation heating efficiency increases, but the extent of concentration and collimation of radiative energy decreases. For real design of the heating device, some trade-offs are needed to balance the radiation heating efficiency and the uniformity of radiative heating of object surface

  12. High Efficiency R-744 Commercial Heat Pump Water Heaters

    Energy Technology Data Exchange (ETDEWEB)

    Elbel, Dr. Stefan W.; Petersen, Michael


    The project investigated the development and improvement process of a R744 (CO2) commercial heat pump water heater (HPWH) package of approximately 35 kW. The improvement process covered all main components of the system. More specific the heat exchangers (Internal heat exchanger, Evaporator, Gas cooler) as well as the expansion device and the compressor were investigated. In addition, a comparison to a commercially available baseline R134a unit of the same capacity and footprint was made in order to compare performance as well as package size reduction potential.

  13. Efficiency of Microwave Heating of Weakly Loaded Polymeric Nanocomposites (Postprint) (United States)


    Nanotube‐Based Theranostic Agents for Microwave Detection and Treatment of Breast Cancer : Enhanced Dielectric and Heating Response of Tissue...enhanced microwave absorption provides prospective biomedical applications including cancer treatment [3, 4] and also electromagnetic interference

  14. High Efficiency Microchannel Diamond Heat Sinks, Phase I (United States)

    National Aeronautics and Space Administration — While absolute power levels in microelectronic devices are relatively modest (a few tens to a few hundred watts), heat fluxes can be significant (~50 W/cm2 in...

  15. Energy efficiency improvements utilising mass flow control and a ring topology in a district heating network

    International Nuclear Information System (INIS)

    Laajalehto, Tatu; Kuosa, Maunu; Mäkilä, Tapio; Lampinen, Markku; Lahdelma, Risto


    Heating and cooling have a major role in the energy sector, covering 46% of total final energy use worldwide. District heating (DH) is a significant technology for improving the energy efficiency of heating systems in communities, because it enables waste heat sources to be utilised economically and therefore significantly reduces the environmental impacts of power generation. As a result of new and more stringent construction regulations for buildings, the heat demands of individual buildings are decreasing and more energy-efficient heating systems have to be developed. In this study, the energy efficiency of a new DH system which includes both a new control system called mass flow control and a new network design called a ring network is examined. A topology in the Helsinki region is studied by using a commercial DH network modelling tool, Grades Heating. The district heating network is attached to a wood-burning heat station which has a heat recovery system in use. Examination is performed by means of both technical and economic analysis. The new non-linear temperature programme that is required is adopted for supply and return temperatures, which allows greater temperature cooling and smaller flow rates. Lower district heating water temperatures are essential when reducing the heat losses in the network and heat production. Mass flow control allows smaller pressure drops in the network and thus reduces the pumping power. The aim of this study was to determine the most energy-efficient DH water supply temperatures in the case network. If the ring network design is utilised, the district heating system is easier to control. As a result the total heat consumption within the heating season is reduced compared to traditional DH systems. On the basis of the results, the new DH system is significantly more energy-efficient in the case network that was examined than the traditional design. For example, average energy losses within the constraints (which consist of heat

  16. New configurations of a heat recovery absorption heat pump integrated with a natural gas boiler for boiler efficiency improvement

    International Nuclear Information System (INIS)

    Qu, Ming; Abdelaziz, Omar; Yin, Hongxi


    Highlights: • Thermal and heat transfer models of absorption heat pumps driven by exhaust gas, hot water, or natural gas. • Natural gas boiler combustion model. • Heat exchanger for condensing. • Experimental data of a hot water absorption heat pump. • Economic assessment of heat recovery absorption heat pump for improving natural gas boilers. - Abstract: Conventional natural gas-fired boilers exhaust flue gas direct to the atmosphere at 150–200 °C, which, at such temperatures, contains large amount of energy and results in relatively low thermal efficiency ranging from 70% to 80%. Although condensing boilers for recovering the heat in the flue gas have been developed over the past 40 years, their present market share is still less than 25%. The major reason for this relatively slow acceptance is the limited improvement in the thermal efficiency of condensing boilers. In the condensing boiler, the temperature of the hot water return at the range of 50–60 °C, which is used to cool the flue gas, is very close to the dew point of the water vapor in the flue gas. Therefore, the latent heat, the majority of the waste heat in the flue gas, which is contained in the water vapor, cannot be recovered. This paper presents a new approach to improve boiler thermal efficiency by integrating absorption heat pumps with natural gas boilers for waste heat recovery (HRAHP). Three configurations of HRAHPs are introduced and discussed. The three configurations are modeled in detail to illustrate the significant thermal efficiency improvement they attain. Further, for conceptual proof and validation, an existing hot water-driven absorption chiller is operated as a heat pump at operating conditions similar to one of the devised configurations. An overall system performance and economic analysis are provided for decision-making and as evidence of the potential benefits. These three configurations of HRAHP provide a pathway to achieving realistic high-efficiency natural

  17. Heat transfer efficient thermal energy storage for steam generation

    International Nuclear Information System (INIS)

    Adinberg, R.; Zvegilsky, D.; Epstein, M.


    A novel reflux heat transfer storage (RHTS) concept for producing high-temperature superheated steam in the temperature range 350-400 deg. C was developed and tested. The thermal storage medium is a metallic substance, Zinc-Tin alloy, which serves as the phase change material (PCM). A high-temperature heat transfer fluid (HTF) is added to the storage medium in order to enhance heat exchange within the storage system, which comprises PCM units and the associated heat exchangers serving for charging and discharging the storage. The applied heat transfer mechanism is based on the HTF reflux created by a combined evaporation-condensation process. It was shown that a PCM with a fraction of 70 wt.% Zn in the alloy (Zn70Sn30) is optimal to attain a storage temperature of 370 deg. C, provided the heat source such as solar-produced steam or solar-heated synthetic oil has a temperature of about 400 deg. C (typical for the parabolic troughs technology). This PCM melts gradually between temperatures 200 and 370 deg. C preserving the latent heat of fusion, mainly of the Zn-component, that later, at the stage of heat discharge, will be available for producing steam. The thermal storage concept was experimentally studied using a lab scale apparatus that enabled investigating of storage materials (the PCM-HTF system) simultaneously with carrying out thermal performance measurements and observing heat transfer effects occurring in the system. The tests produced satisfactory results in terms of thermal stability and compatibility of the utilized storage materials, alloy Zn70Sn30 and the eutectic mixture of biphenyl and diphenyl oxide, up to a working temperature of 400 deg. C. Optional schemes for integrating the developed thermal storage into a solar thermal electric plant are discussed and evaluated considering a pilot scale solar plant with thermal power output of 12 MW. The storage should enable uninterrupted operation of solar thermal electric systems during additional hours

  18. Neutron stars with outbursts from superfluid crust (United States)

    Kaminker, A. D.; Chaikin, E. A.; Kaurov, A. A.; Yakovlev, D. G.


    We model heat propagation and the thermal surface luminosity L{s}^∞ ≤ft( t \\right) of a neutron star after an internal outburst in its crust. Simulations take into account superfluidity of free neutrons and the thickness of the outbursting layer (heater) in the crust. Crustal superfluidity can shorten and intensify variations of L{s}^∞ ≤ft( t \\right).

  19. The effectiveness of absorption heat pumps application for the increase of economic efficiency of CHP operation

    Directory of Open Access Journals (Sweden)

    Luzhkovoy Dmitriy S.


    Full Text Available The article deals with a comparative analysis of CHP operational efficiency in various working modes before and after the absorption heat pumps installation. The calculation was performed using a mathematical model of the extraction turbine PT- 80/100-130/13. Absorption heat pumps of LLC “OKB Teplosibmash” were used as AHP models for the analysis. The most effective way of absorption lithium-bromide heat pumps application as a part of the turbine PT-80/100-130/13 turned out to be their usage in a heat-producing mode during a non-heating season with a load of hot water supply. For this mode the dependence of the turbine heat efficiency on the heat load of the external consumer at a given throttle flow was analyzed.

  20. Lightweight and Energy Efficient Heat Pump, Phase II (United States)

    National Aeronautics and Space Administration — Future Spacecraft from the JPL will require increasingly sophisticated thermal control technology. A need exists for efficient, lightweight Vapor Compression Cycle...

  1. Technical-and-Economic Efficiency of Draft Enriched with Oxygen in Small-Capacity Heating Boilers

    Directory of Open Access Journals (Sweden)

    P. Ratnikov


    Full Text Available Data on complex experimental and theoretical investigations pertaining to efficiency of oxygen-enriched draft in the small-capacity heating boilers as exemplified by the plant HEIZA (HW-S-10/K have been presented in the paper. The paper provides a calculation model of heating processes in heat generator burner (as exemplified by HEIZA plant. Simulation of heating processes in the operational zone has been executed in paper. The experimental data have proved model adequacy. The calculation scheme of the plant will be used in future for determination of power and ecological efficiency of draft enrichment with oxygen.

  2. maximum conversion efficiency of thermionic heat to electricity

    African Journals Online (AJOL)


    electron flow is called thermionic emission (Houston,. 1959 ; Baragiola and Bringa, 2006). The process of converting thermal energy (heat) to a useful electrical work by the phenomenon of thermionic emission is the fundamental concept applied to a cylindrical version of the planner converter, considered as the building ...

  3. Modeling heat efficiency, flow and scale-up in the corotating disc scraped surface heat exchanger

    DEFF Research Database (Denmark)

    Friis, Alan; Szabo, Peter; Karlson, Torben


    A comparison of two different scale corotating disc scraped surface heat exchangers (CDHE) was performed experimentally. The findings were compared to predictions from a finite element model. We find that the model predicts well the flow pattern of the two CDHE's investigated. The heat transfer...... performance predicted by the model agrees well with experimental observations for the laboratory scale CDHE whereas the overall heat transfer in the scaled-up version was not in equally good agreement. The lack of the model to predict the heat transfer performance in scale-up leads us to identify the key...

  4. Costa Rica Rift Revisited: Constraints on Shallow and Deep Hydrothermal Circulation in Oceanic Crust (United States)

    Davis, E. E.; Becker, K.; He, J.


    New heat-flow observations made along two seismic reflection profiles on 6 Ma crust of the Costa Rica Rift flank show an inverse correlation between heat flow and sediment thickness similar to that observed on other sedimented ridges and young ridge flanks. Extrapolation of the seafloor heat-flow values to the top of the igneous crust - justified by comparing seafloor and borehole determinations where observations are colocated - show the surface of the igneous crust to be of uniform temperature despite large local sediment thickness variations. This is consistent with observations made at DSDP/ODP Holes 504B and 896A where basement temperatures are observed to be nearly identical, also despite contrasting sediment thicknesses. Efficient lateral heat exchange via vigorous crustal hydrothermal circulation is required to create the degree of uniformity inferred and observed. Permeability measurements at the two drill sites show that this vigorous circulation may be restricted to as little as the uppermost tens of m of the crust. Permeability determined deeper in Hole 504B is too low to permit thermally significant flow, although temperature logs suggest that thermally significant flow extends throughout the 2 km section penetrated at Site 504, presumably via pathways not intersected by the borehole. The laterally uniform temperatures in the uppermost igneous crust here and elsewhere are remarkable given the small apparent depth-extent of the circulation that so efficiently distributes heat. While certainly not as vigorous, the circulation at depth suggested by the temperature logs at Site 504 is also noteworthy; unfortunately the observation cannot be generalized because of the lack of other deep crustal holes that could permit direct observations, and the lack of a method for inferring deep hydrothermal structure.

  5. Analysis of the efficiency of a hybrid foil tunnel heating system (United States)

    Kurpaska, Sławomir; Pedryc, Norbert


    The paper analyzes the efficiency of the hybrid system used to heat the foil tunnel. The tested system was built on the basis of heat gain in a cascade manner. The first step is to heat the water in the storage tank using the solar collectors. The second stage is the use of a heat pump (HP) in order to heat the diaphragm exchangers. The lower HP heat source is a cascade first stage buffer. In the storage tank, diaphragm exchangers used for solar collectors and heat pumps are installed. The research was carried out at a research station located in the University of Agriculture in Cracow. The aim was to perform an analysis of the efficiency of a hybrid system for the heating of a foil tunnel in the months from May to September. The efficiency of the entire hybrid system was calculated as the relation of the effect obtained in reference to the electrical power used to drive the heat pump components (compressor drive, circulation pump), circulation pumps and fans installed in the diaphragm heaters. The resulting effect was the amount of heat supplied to the interior of the object as a result of the internal air being forced through the diaphragm exchangers.

  6. Analysis of the efficiency of a hybrid foil tunnel heating system

    Directory of Open Access Journals (Sweden)

    Kurpaska Sławomir


    Full Text Available The paper analyzes the efficiency of the hybrid system used to heat the foil tunnel. The tested system was built on the basis of heat gain in a cascade manner. The first step is to heat the water in the storage tank using the solar collectors. The second stage is the use of a heat pump (HP in order to heat the diaphragm exchangers. The lower HP heat source is a cascade first stage buffer. In the storage tank, diaphragm exchangers used for solar collectors and heat pumps are installed. The research was carried out at a research station located in the University of Agriculture in Cracow. The aim was to perform an analysis of the efficiency of a hybrid system for the heating of a foil tunnel in the months from May to September. The efficiency of the entire hybrid system was calculated as the relation of the effect obtained in reference to the electrical power used to drive the heat pump components (compressor drive, circulation pump, circulation pumps and fans installed in the diaphragm heaters. The resulting effect was the amount of heat supplied to the interior of the object as a result of the internal air being forced through the diaphragm exchangers.

  7. Improving urban district heating systems and assessing the efficiency of the energy usage therein (United States)

    Orlov, M. E.; Sharapov, V. I.


    The report describes issues in connection with improving urban district heating systems from combined heat power plants (CHPs), to propose the ways for improving the reliability and the efficiency of the energy usage (often referred to as “energy efficiency”) in such systems. The main direction of such urban district heating systems improvement suggests transition to combined heating systems that include structural elements of both centralized and decentralized systems. Such systems provide the basic part of thermal power via highly efficient methods for extracting thermal power plants turbines steam, while peak loads are covered by decentralized peak thermal power sources to be mounted at consumers’ locations, with the peak sources being also reserve thermal power sources. The methodology was developed for assessing energy efficiency of the combined district heating systems, implemented as a computer software product capable of comparatively calculating saving on reference fuel for the system.

  8. Effects of the distribution density of a biomass combined heat and power plant network on heat utilisation efficiency in village-town systems. (United States)

    Zhang, Yifei; Kang, Jian


    The building of biomass combined heat and power (CHP) plants is an effective means of developing biomass energy because they can satisfy demands for winter heating and electricity consumption. The purpose of this study was to analyse the effect of the distribution density of a biomass CHP plant network on heat utilisation efficiency in a village-town system. The distribution density is determined based on the heat transmission threshold, and the heat utilisation efficiency is determined based on the heat demand distribution, heat output efficiency, and heat transmission loss. The objective of this study was to ascertain the optimal value for the heat transmission threshold using a multi-scheme comparison based on an analysis of these factors. To this end, a model of a biomass CHP plant network was built using geographic information system tools to simulate and generate three planning schemes with different heat transmission thresholds (6, 8, and 10 km) according to the heat demand distribution. The heat utilisation efficiencies of these planning schemes were then compared by calculating the gross power, heat output efficiency, and heat transmission loss of the biomass CHP plant for each scenario. This multi-scheme comparison yielded the following results: when the heat transmission threshold was low, the distribution density of the biomass CHP plant network was high and the biomass CHP plants tended to be relatively small. In contrast, when the heat transmission threshold was high, the distribution density of the network was low and the biomass CHP plants tended to be relatively large. When the heat transmission threshold was 8 km, the distribution density of the biomass CHP plant network was optimised for efficient heat utilisation. To promote the development of renewable energy sources, a planning scheme for a biomass CHP plant network that maximises heat utilisation efficiency can be obtained using the optimal heat transmission threshold and the nonlinearity

  9. Thermal Efficiency of Power Module “Boiler with Solar Collectors as Additional Heat Source” For Combined Heat Supply System

    Directory of Open Access Journals (Sweden)

    Denysova A.E.


    Full Text Available The purpose of work is to increase the efficiency of the combined heat supply system with solar collectors as additional thermal generators. In order to optimize the parameters of combined heat supply system the mathematical modeling of thermal processes in multi module solar collectors as additional thermal generators for preheating of the water for boiler have been done. The method of calculation of multi-module solar collectors working with forced circulation for various configurations of hydraulic connection of solar collector modules as the new result of our work have been proposed. The results of numerical simulation of thermal efficiency of solar heat source for boiler of combined heat supply system with the account of design features of the circuit; regime parameters of thermal generators that allow establishing rational conditions of its functioning have been worked out. The conditions of functioning that provide required temperature of heat carrier incoming to boiler and value of flow rate at which the slippage of heat carrier is not possible for different hydraulic circuits of solar modules have been established.

  10. Quantifying Systemic Efficiency using Exergy and Energy Analysis for Ground Source Heat Pumps: Domestic Space Conditioning and Water Heating Applications.

    Energy Technology Data Exchange (ETDEWEB)

    Ally, Moonis Raza [ORNL; Baxter, Van D [ORNL; Gehl, Anthony C [ORNL; Munk, Jeffrey D [ORNL


    Although air temperatures over land surfaces show wide seasonal and daily variations, the ground, approximately 10 meters below the earth s surface, remains relatively stable in temperature thereby serving as an energy source or sink. Ground source heat pumps can heat, cool, and supply homes with hot water efficiently by utilizing the earth s renewable and essentially inexhaustible energy resources, saving fossil fuels, reducing greenhouse gas emissions, and lowering the environmental footprint. In this paper, evidence is shown that ground source heat pumps can provide up to 79%-87% of domestic hot water energy needs, and up to 77% of space heating needs with the ground s thermal energy resources. The case refers to a 12-month study conducted at a 253 m2 research house located in Oak Ridge, Tennessee, 36.01 N 84.26 W in a mixed-humid climate with HDD of 2218 C-days and CDD of 723 C-days under simulated occupancy conditions. A single 94.5m vertical bore interfaced the heat pump with the ground. The research shows that this technology is capable of achieving US DOE targets of 25 % and 35% energy savings in HVAC, and in water heating, respectively by 2030. It is also a viable technology to meet greenhouse gas target emissions under the IECC 2012 Standard, as well as the European Union (EU) 2020 targets of using renewable energy resources. The paper quantifies systemic efficiencies using Exergy analysis of the major components, clearly pointing areas for further improvement.

  11. A Compact, Light-weight, Reliable and Highly Efficient Heat Pump for, Phase I (United States)

    National Aeronautics and Space Administration — RTI proposes to develop an efficient, reliable, compact and lightweight heat pump for space applications. The proposed effort is expected to lead to (at the end of...

  12. High Efficiency, High Temperature Foam Core Heat Exchanger for Fission Surface Power Systems, Phase II (United States)

    National Aeronautics and Space Administration — Fission-based power systems with power levels of 30 to ≥100 kWe will be needed for planetary surface bases. Development of high temperature, high efficiency heat...

  13. Economic efficiency of a gas-turbine topping for steam reheating at heating turbo-installations


    Romashova Olga; Belyaev Leonid; Tubolev Aleksandr; Skrebatun Egor


    The article considers the ways to improve the operating efficiency of conventional combined heat power plants using gas-turbine topping scheme allowing heat utilization of flue gases for steam reheating in the waste-heat steam boiler. The calculating analysis was performed for a steam-turbine power generating unit with a turbine of the Т-110/120-130 brand name intended for various modes of operation.

  14. Evaluation of Energy Efficient Options to Heat Ohio Department of Transportation (ODOT) Maintenance Facilities (United States)


    This project was initiated by the ODOT District 2 staff who were looking for more efficient ways to heat and operate their maintenance facilities. This especially applied to the idea of using radiant floor heating as an alternative to todays stand...

  15. Efficiency gains in Danish district heating. Is there anything to learn from benchmarking?

    DEFF Research Database (Denmark)

    Munksgaard, Jesper; Pade, Lise-Lotte; Fristrup, P.


    Facing a market structure of independent heating systems and cost-of-service regulation the regulator considers ways to create incentives for increasing efficiency in heat production.One way is to implement benchmark regulation. The aim of this paper is twofold: (1) To investigate the potential f...

  16. Recovery Act: Tennessee Energy Efficient Schools Initiative Ground Source Heat Pump Program

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Terry [Townsend Engineering, Inc., Davenport, IA (United States); Slusher, Scott [Townsend Engineering, Inc., Davenport, IA (United States)


    The Tennessee Energy Efficient Schools Initiative (EESI) Hybrid-Water Source Heat Pump (HY-GSHP) Program sought to provide installation costs and operation costs for different Hybrid water source heat pump systems’ configurations so that other State of Tennessee School Districts will have a resource for comparison purposes if considering a geothermal system.

  17. On the importance of specific heats as regards efficiency increases for highly dilute IC engines

    International Nuclear Information System (INIS)

    Caton, Jerald A.


    Highlights: • Importance of specific heats towards increasing engine efficiency was quantified. • Decreases of specific heats contribute 3.5–6.3% (abs) to the efficiency. • Dilute engines benefit from decreases of specific heats due to lower temperatures. - Abstract: Engineering and scientific efforts continue with the development of advanced, IC engines using highly dilute mixtures, and relatively high compression ratios. Such engines are known to provide opportunities for low emissions as well as high efficiencies. The main features of these engines include higher compression ratios, lean operation, use of EGR, and shorter burn durations. First, this study reviews the quantitative contributions of each of these features as determined by an engine cycle simulation. Second, this study provides the quantitative contributions to the increased efficiency in terms of fundamental thermodynamic considerations. An automotive engine operated at 2000 rpm was selected for this study. For the conditions examined, the net indicated thermal efficiency increased from 37.0% (conventional engine) to 53.9% (high efficiency engine) – for an incremental increase of 16.9% (absolute). The contribution of increases of the ratio of specific heats towards the final thermal efficiency is quantified. This aspect has been well known, but has not been quantified for actual engines. For the various conditions examined, 21–35% of the total efficiency improvement was estimated to be due to the increase of the ratio of specific heats

  18. Heat Shock-Enhanced Conjugation Efficiency in Standard Campylobacter jejuni Strains


    Zeng, Ximin; Ardeshna, Devarshi; Lin, Jun


    Campylobacter jejuni, the leading bacterial cause of human gastroenteritis in the United States, displays significant strain diversity due to horizontal gene transfer. Conjugation is an important horizontal gene transfer mechanism contributing to the evolution of bacterial pathogenesis and antimicrobial resistance. It has been observed that heat shock could increase transformation efficiency in some bacteria. In this study, the effect of heat shock on C. jejuni conjugation efficiency and the ...

  19. Review on Microwave-Matter Interaction Fundamentals and Efficient Microwave-Associated Heating Strategies (United States)

    Sun, Jing; Wang, Wenlong; Yue, Qinyan


    Microwave heating is rapidly emerging as an effective and efficient tool in various technological and scientific fields. A comprehensive understanding of the fundamentals of microwave–matter interactions is the precondition for better utilization of microwave technology. However, microwave heating is usually only known as dielectric heating, and the contribution of the magnetic field component of microwaves is often ignored, which, in fact, contributes greatly to microwave heating of some aqueous electrolyte solutions, magnetic dielectric materials and certain conductive powder materials, etc. This paper focuses on this point and presents a careful review of microwave heating mechanisms in a comprehensive manner. Moreover, in addition to the acknowledged conventional microwave heating mechanisms, the special interaction mechanisms between microwave and metal-based materials are attracting increasing interest for a variety of metallurgical, plasma and discharge applications, and therefore are reviewed particularly regarding the aspects of the reflection, heating and discharge effects. Finally, several distinct strategies to improve microwave energy utilization efficiencies are proposed and discussed with the aim of tackling the energy-efficiency-related issues arising from the application of microwave heating. This work can present a strategic guideline for the developed understanding and utilization of the microwave heating technology. PMID:28773355

  20. Long-duration heat load measurement approach by novel apparatus design and highly efficient algorithm

    International Nuclear Information System (INIS)

    Zhu, Yanwei; Yi, Fajun; Meng, Songhe; Zhuo, Lijun; Pan, Weizhen


    Improving the surface heat load measurement technique for vehicles in aerodynamic heating environments is imperative, regarding aspects of both the apparatus design and identification efficiency. A simple novel apparatus is designed for heat load identification, taking into account the lessons learned from several aerodynamic heating measurement devices. An inverse finite difference scheme (invFDM) for the apparatus is studied to identify its surface heat flux from the interior temperature measurements with high efficiency. A weighted piecewise regression filter is also proposed for temperature measurement prefiltering. Preliminary verification of the invFDM scheme and the filter is accomplished via numerical simulation experiments. Three specific pieces of apparatus have been concretely designed and fabricated using different sensing materials. The aerodynamic heating process is simulated by an inductively coupled plasma wind tunnel facility. The identification of surface temperature and heat flux from the temperature measurements is performed by invFDM. The results validate the high efficiency, reliability and feasibility of heat load measurements with different heat flux levels utilizing the designed apparatus and proposed method. (paper)

  1. Long-duration heat load measurement approach by novel apparatus design and highly efficient algorithm (United States)

    Zhu, Yanwei; Yi, Fajun; Meng, Songhe; Zhuo, Lijun; Pan, Weizhen


    Improving the surface heat load measurement technique for vehicles in aerodynamic heating environments is imperative, regarding aspects of both the apparatus design and identification efficiency. A simple novel apparatus is designed for heat load identification, taking into account the lessons learned from several aerodynamic heating measurement devices. An inverse finite difference scheme (invFDM) for the apparatus is studied to identify its surface heat flux from the interior temperature measurements with high efficiency. A weighted piecewise regression filter is also proposed for temperature measurement prefiltering. Preliminary verification of the invFDM scheme and the filter is accomplished via numerical simulation experiments. Three specific pieces of apparatus have been concretely designed and fabricated using different sensing materials. The aerodynamic heating process is simulated by an inductively coupled plasma wind tunnel facility. The identification of surface temperature and heat flux from the temperature measurements is performed by invFDM. The results validate the high efficiency, reliability and feasibility of heat load measurements with different heat flux levels utilizing the designed apparatus and proposed method.

  2. Developing HEAT Scores with H-Res Thermal Imagery to Support Urban Energy Efficiency (United States)

    Hemachandran, Bharanidharan

    As part of The Calgary Community GHG Reduction Plan (2009) The City is seeking an implementation strategy to reduce GHGs and promote low-carbon living, with a focus on improving urban energy efficiency. The most cited obstacle to energy efficiency improvements is the lack of interest from consumers (CUI, 2008). However, Darby (2006) has shown that effective feedback significantly reduces energy consumption. To exploit these findings, the HEAT (Heat Energy Assessment Technologies) Geoweb project integrates high-resolution (H-Res) airborne thermal imagery (TABI 1800) to provide unique energy efficiency feedback to Calgary homeowners in the form of interactive HEAT Maps and Hot Spots (Hay et al., 2011). As a part of the HEAT Phase II program, the goal of this research is to provide enhanced feedback support for urban energy efficiency by meeting two key objectives: (i) develop an appropriate method to define HEAT Scores using TABI 1800 imagery that allows for the comparison of waste heat of one or more houses with all other mapped houses in the community and city, and (ii) develop a multi-scale interactive Geoweb interface that displays the HEAT Scores at City, Community and Residential scales. To achieve these goals, we describe the evolution of three novel HEAT Score techniques based on: (i) a Standardized Score, (ii) the WUFIRTM model and Logistic Regression and (iii ) a novel criteria weighted method that considers: (a) heat transfer through different roofing materials, (b) local climatic conditions and (c) house age and living area attributes. Furthermore, (d) removing or adding houses to analysis based on this 3rd technique, does not affect the HEAT Score of other houses and (e) HEAT Scores can be compared within and across different cities. We also describe how HEAT Scores are incorporated within the HEAT Geoweb architecture. It is envisioned that HEAT Scores will promote energy efficiency among homeowners and urban city planners, as they will quantify and

  3. Implementation Of Online Heat Exchanger Efficiency Calculation And Fouling Monitoring At Crude Unit

    Directory of Open Access Journals (Sweden)

    Mohammed Hegazy


    Full Text Available Abstract The heat exchangers on crude distillation units need to deliver high heat transfer efficiency and operational reliability. Most of heat exchangers used in crude distillation units are Cross-flow two-stream. The two streams flow at right angles to each other. This flow configuration is intermediate in effectiveness between parallel-flow and counter flow exchangers but it is often simpler to construct owing to the relative simpler to construct owing to the relative simplicity of the inlet and outlet flow ducts. Use of the Smart Online Efficiency online calculation to monitor the heat exchangers performance and efficiency at Crude units in Mina Al-Ahmadi Refinery MAA yielded early results when the tool highlighted a fouling event shortly after it occurred. Fouling formation in any heat exchanger will reduce the online-calculated heat exchanger efficiency result and that can noted from the trend of histories efficiency data and from the fouling indicator. This paper looks at the efficiency calculation and fouling monitoring using DCS software application and the result from the case study.

  4. Evaluating humidity recovery efficiency of currently available heat and moisture exchangers: a respiratory system model study

    Directory of Open Access Journals (Sweden)

    Jeanette Janaina Jaber Lucato


    Full Text Available OBJECTIVES: To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate. INTRODUCTION: Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers' humidifying performance. METHODS: Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37°C, a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH was calculated for each setting. RESULTS: Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow. CONCLUSIONS: Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers.

  5. Evaluating humidity recovery efficiency of currently available heat and moisture exchangers: a respiratory system model study. (United States)

    Lucato, Jeanette Janaina Jaber; Adams, Alexander Bernard; Souza, Rogério; Torquato, Jamili Anbar; Carvalho, Carlos Roberto Ribeiro; Marini, John J


    To evaluate and compare the efficiency of humidification in available heat and moisture exchanger models under conditions of varying tidal volume, respiratory rate, and flow rate. Inspired gases are routinely preconditioned by heat and moisture exchangers to provide a heat and water content similar to that provided normally by the nose and upper airways. The absolute humidity of air retrieved from and returned to the ventilated patient is an important measurable outcome of the heat and moisture exchangers' humidifying performance. Eight different heat and moisture exchangers were studied using a respiratory system analog. The system included a heated chamber (acrylic glass, maintained at 37 degrees C), a preserved swine lung, a hygrometer, circuitry and a ventilator. Humidity and temperature levels were measured using eight distinct interposed heat and moisture exchangers given different tidal volumes, respiratory frequencies and flow-rate conditions. Recovery of absolute humidity (%RAH) was calculated for each setting. Increasing tidal volumes led to a reduction in %RAH for all heat and moisture exchangers while no significant effect was demonstrated in the context of varying respiratory rate or inspiratory flow. Our data indicate that heat and moisture exchangers are more efficient when used with low tidal volume ventilation. The roles of flow and respiratory rate were of lesser importance, suggesting that their adjustment has a less significant effect on the performance of heat and moisture exchangers.

  6. Thermal Efficiency of Cogeneration Units with Multi-Stage Reheating for Russian Municipal Heating Systems

    Directory of Open Access Journals (Sweden)

    Evgeny Lisin


    Full Text Available This paper explores the layout of an optimum process for supplying heat to Russian municipal heating systems operating in a market environment. We analyze and compare the standard cogeneration unit design with two-stage reheating of service water coming from controlled extraction locations and layouts that employ three in-line reheaters with heat the supply controlled by a rotary diaphragm and qualitative/quantitative methods (so-called “uncontrolled extraction”. Cogeneration unit designs are benchmarked in terms of their thermal efficiency expressed as a fuel consumption rate. The specific fuel consumption rate on electricity production is viewed as a key parameter of thermal efficiency.

  7. Biomimic design of multi-scale fabric with efficient heat transfer property

    Directory of Open Access Journals (Sweden)

    Fan Jie


    Full Text Available Wool fiber has a complex hierarchic structure. The multi-scale fibrils are assembled to form a tree-like channel net in wool fiber, providing an efficient heat transfer property. The optimal inner configuration of wool fiber can also be invited to biomimic design of textile fabrics to improve the thermal comfort of cloth. A heat transfer model of biomimic multi-scale fabric using the fractal derivative is established. Theoretical analysis indicates that the heat flux efficiency in the biomimic fabric can be 2 orders of magnitude comparing with that of the continuous medium.

  8. Calculation of Efficiencies of a Ship Power Plant Operating with Waste Heat Recovery through Combined Heat and Power Production

    Directory of Open Access Journals (Sweden)

    Mirko Grljušić


    Full Text Available The aim of this research was to investigate the possibility of a combined heat & power (CHP plant, using the waste heat from a Suezmax-size oil tanker’s main engine, to meet all heating and electricity requirements during navigation. After considering various configurations, a standard propulsion engine operating at maximum efficiency, combined with a supercritical Organic Rankine cycle (ORC system, was selected to supply the auxiliary power, using R245fa or R123 as the working fluid. The system analysis showed that such a plant can meet all heat and electrical power requirements at full load, with the need to burn only a small amount of supplementary fuel in a heat recovery steam generator (HRSG when the main engine operates at part load. Therefore, it is possible to increase the overall thermal efficiency of the ship’s power plant by more than 5% when the main engine operates at 65% or more of its specified maximum continuous rating (SMCR.

  9. Design of functionally graded wood-based board for floor heating system with higher energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Obata, Y.; Kanayama, K. [Advanced Wood-based Material Technology Group, Inst. for Structural and Engineering Materials, National Inst. of Advanced Industrial Science and Technology, Nagoya (Japan); Takeuchi, K.; Kawazoe, M. [NEDO Industrial Technology Researchers, Nagoya (Japan)


    Recycling of wood building waste has been required and wood boards are prospective recycled materials. The concept of FGM was introduced to the wood board as a base material of a floor heating system to develop an FGM board with higher energy efficiency. Two-dimensional unsteady heat transfer problem in an FGM plate with material properties of wood was analyzed, which modeled the state that the base material was heated partially. The Laplace transform and the perturbation method were applied for the analysis. The tactile warmth of a facing plate in the floor heating system, which touches to human sole directly, was discussed to avoid losing the goodness of wood. (orig.)

  10. High Efficiency Heat Exchanger for High Temperature and High Pressure Applications

    Energy Technology Data Exchange (ETDEWEB)

    Sienicki, James J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Lv, Qiuping [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division


    CompRex, LLC (CompRex) specializes in the design and manufacture of compact heat exchangers and heat exchange reactors for high temperature and high pressure applications. CompRex’s proprietary compact technology not only increases heat exchange efficiency by at least 25 % but also reduces footprint by at least a factor of ten compared to traditional shell-and-tube solutions of the same capacity and by 15 to 20 % compared to other currently available Printed Circuit Heat Exchanger (PCHE) solutions. As a result, CompRex’s solution is especially suitable for Brayton cycle supercritical carbon dioxide (sCO2) systems given its high efficiency and significantly lower capital and operating expenses. CompRex has already successfully demonstrated its technology and ability to deliver with a pilot-scale compact heat exchanger that was under contract by the Naval Nuclear Laboratory for sCO2 power cycle development. The performance tested unit met or exceeded the thermal and hydraulic specifications with measured heat transfer between 95 to 98 % of maximum heat transfer and temperature and pressure drop values all consistent with the modeled values. CompRex’s vision is to commercialize its compact technology and become the leading provider for compact heat exchangers and heat exchange reactors for various applications including Brayton cycle sCO2 systems. One of the limitations of the sCO2 Brayton power cycle is the design and manufacturing of efficient heat exchangers at extreme operating conditions. Current diffusion-bonded heat exchangers have limitations on the channel size through which the fluid travels, resulting in excessive solid material per heat exchanger volume. CompRex’s design allows for more open area and shorter fluid proximity for increased heat transfer efficiency while sustaining the structural integrity needed for the application. CompRex is developing a novel improvement to its current heat exchanger design where fluids are directed to alternating

  11. A rhyolite to dacite sequence of volcanism directly from the heated lower crust: Late Pleistocene to Holocene Numazawa volcano, NE Japan (United States)

    Yamamoto, Takahiro


    Flare-up of silicic volcanism has occurred in the back arc of NE Japan arc since 0.3 Ma; Sunagohara, Numazawa, Kinunuma, Hiuchigatake and Iiji volcanoes have all grown during this time interval. Although arc front volcanism has continued during the Quaternary period, back-arc volcanism varies in space and time. All ejecta of the back-arc volcanoes are medium-K calc-alkaline rhyolite to dacite in composition and 1 to 10 DRE km 3 in volume. The Sr and Nd isotopic ratios of the ejecta vary widely among the individual volcanoes and suggest the origin of the felsic magmas may be generated by anatexis of mafic igneous rocks of the lower crust. Temporal variation in geochemistry of the 5 km 3 Numazawa ejecta shows more details of the anatexis. Numazawa volcano erupted the Shibahara pyroclastics at 110 ka, the Mukuresawa lava at 70 ka, the Mizunuma pyroclastics at 45 ka, the Sozan lava at 40 ka, the Maeyama lava at 20 ka, and the Numazawako pyroclastics at 4.6 ka. The time-accumulated volume diagram of Numazawa volcano shows the increase of magma eruption rate through time. All elements of the Numazawa rhyolite to dacite define time-controlled, discontinuous linear trends. SiO 2, K 2O, Na 2O, Rb, Y, Ba, and Nb decrease with the ascending eruption units, whereas MgO, Fe 2O 3, CaO, Al 2O 3, TiO 2, Sr and V increase. SiO 2 contents are variable from 72% in Nm-MK at 71 ka to 66% in Nm-NK at 4.6 ka. The rhyolite to dacite of the Numazawa ejecta are homogeneous with respect to the isotopic ratios. I show that the temporal linear trends for the bulk compositions of the Numazawa rhyolite to dacite are most plausibly caused by increase of batch partial melting at constant bulk distribution coefficient. The calculated patterns of trace-element abundances show that partial melting of high-alumina basaltic igneous rocks in the lower crust can generate the Numazawa rhyolite to dacite. In this case, the degree of partial melting varies from about 20% at 71 ka to about 60% at 20 ka and 4

  12. Efficiency Analysis of Independent and Centralized Heating Systems for Residential Buildings in Northern Italy

    Directory of Open Access Journals (Sweden)

    Fabio Rinaldi


    Full Text Available The primary energy consumption in residential buildings is determined by the envelope thermal characteristics, air change, outside climatic data, users’ behaviour and the adopted heating system and its control. The new Italian regulations strongly suggest the installation of centralized boilers in renovated buildings with more than four apartments. This work aims to investigate the differences in primary energy consumption and efficiency among several independent and centralized heating systems installed in Northern Italy. The analysis is carried out through the following approach: firstly building heating loads are evaluated using the software TRNSYS® and, then, heating system performances are estimated through a simplified model based on the European Standard EN 15316. Several heating systems have been analyzed, evaluating: independent and centralized configurations, condensing and traditional boilers, radiator and radiant floor emitters and solar plant integration. The heating systems are applied to four buildings dating back to 2010, 2006, 1960s and 1930s. All the combinations of heating systems and buildings are analyzed in detail, evaluating efficiency and primary energy consumption. In most of the cases the choice between centralized and independent heating systems has minor effects on primary energy consumption, less than 3%: the introduction of condensing technology and the integration with solar heating plant can reduce energy consumption by 11% and 29%, respectively.

  13. Achievements and suggestions of heat metering and energy efficiency retrofit for existing residential buildings in northern heating regions of China

    International Nuclear Information System (INIS)

    Yan Ding; Zhe Tian; Yong Wu; Neng Zhu


    In order to promote energy efficiency and emission reduction, the importance of improving building energy efficiency received sufficient attention from Chinese Government. The heat metering and energy efficiency retrofit for existing residential buildings of 0.15 billion m 2 in northern heating regions of China was initiated in 2007 and completed successfully at the end of 2010. This article introduced the background and outline of the retrofit project during the period of 11th five-year plan. Numerous achievements that received by retrofit such as environmental protection effect, improvement of indoor environment, improvement of heating system, investment guidance effect, promotion of relevant industries and increasing chances of employment were concluded. Valuable experience that acquired from the retrofit project during the period of 11th five-year plan was also summarized in this article. By analyzing the main problems emerged in the past, pertinent suggestions were put forward to promote a larger scale and more efficient retrofit project in the period of 12th five-year plan. - Highlights: →Successful implementation of a retrofit project in China is introduced. → Significance of the project contributing to emission reduction is analyzed. →Achievements are summarized and future suggestions are put forward.

  14. Efficiency of utilization of heat of moisture from exhaust gases of heat HRSG of CCGT


    Galashov Nikolay; Tsibulskiy Svyatoslav; Mel’nikov Denis; Kiselev Alexandr; Gabdullina Al’bina


    The paper discusses the technology of utilizing the heat of exhaust gas moisture from heat recovery steam gases (HRSG) of combined-cycle gas turbine (CCGT). Particular attention focused on the influence of the excess air factor on the trapping of the moisture of the exhaust gases, as in the HRSG of the CCGT its value varies over a wider range than in the steam boilers of the TPP. For the research, has been developed a mathematical model that allows to determine the volumes of combustion produ...

  15. Heat Shock-Enhanced Conjugation Efficiency in Standard Campylobacter jejuni Strains. (United States)

    Zeng, Ximin; Ardeshna, Devarshi; Lin, Jun


    Campylobacter jejuni, the leading bacterial cause of human gastroenteritis in the United States, displays significant strain diversity due to horizontal gene transfer. Conjugation is an important horizontal gene transfer mechanism contributing to the evolution of bacterial pathogenesis and antimicrobial resistance. It has been observed that heat shock could increase transformation efficiency in some bacteria. In this study, the effect of heat shock on C. jejuni conjugation efficiency and the underlying mechanisms were examined. With a modified Escherichia coli donor strain, different C. jejuni recipient strains displayed significant variation in conjugation efficiency ranging from 6.2 × 10(-8) to 6.0 × 10(-3) CFU per recipient cell. Despite reduced viability, heat shock of standard C. jejuni NCTC 11168 and 81-176 strains (e.g., 48 to 54°C for 30 to 60 min) could dramatically enhance C. jejuni conjugation efficiency up to 1,000-fold. The phenotype of the heat shock-enhanced conjugation in C. jejuni recipient cells could be sustained for at least 9 h. Filtered supernatant from the heat shock-treated C. jejuni cells could not enhance conjugation efficiency, which suggests that the enhanced conjugation efficiency is independent of secreted substances. Mutagenesis analysis indicated that the clustered regularly interspaced short palindromic repeats system and the selected restriction-modification systems (Cj0030/Cj0031, Cj0139/Cj0140, Cj0690c, and HsdR) were dispensable for heat shock-enhanced conjugation in C. jejuni. Taking all results together, this study demonstrated a heat shock-enhanced conjugation efficiency in standard C. jejuni strains, leading to an optimized conjugation protocol for molecular manipulation of this organism. The findings from this study also represent a significant step toward elucidation of the molecular mechanism of conjugative gene transfer in C. jejuni. Copyright © 2015, American Society for Microbiology. All Rights Reserved.


    Directory of Open Access Journals (Sweden)

    Tovajniansky L.L.


    Full Text Available The drawbacks of the traditional design of the heaters, which make known imperfections in manufacturing processes, realized with the use of electric heating. This determines the need for a radically new design of the heating devices. Created by high-temperature ceramics, characterized by abnormally high thermal stability and clarified the parameters that allow a certain degree change its thermal conductivity. On this basis the contact type ceramic heaters that provide thermal flow direction using different materials in the body of the heater - of high thermal conductivity, the surface facing the heat transfer and low which differs opposite sides of the heater are designed to eliminate the dissipation of heat into the surrounding space. This made it possible to equip the modern production paint industry energy efficient heating equipment with explosion and fire heating system reactors.

  17. Quantum efficiency bound for continuous heat engines coupled to noncanonical reservoirs (United States)

    Agarwalla, Bijay Kumar; Jiang, Jian-Hua; Segal, Dvira


    We derive an efficiency bound for continuous quantum heat engines absorbing heat from squeezed thermal reservoirs. Our approach relies on a full-counting statistics description of nonequilibrium transport and it is not limited to the framework of irreversible thermodynamics. Our result, a generalized Carnot efficiency bound, is valid beyond the small-squeezing and high-temperature limit. Our findings are embodied in a prototype three-terminal quantum photoelectric engine where a qubit converts heat absorbed from a squeezed thermal reservoir into electrical power. We demonstrate that in the quantum regime, the efficiency can be greatly amplified by squeezing. From the fluctuation relation, we further receive other operational measures in linear response, for example, the universal maximum power efficiency bound.

  18. Heat transfer efficiency in grate burning of wood chips - challenges and practical limitations

    Energy Technology Data Exchange (ETDEWEB)

    Rousku, P.


    Small-scale grate boilers are typical way of utilizing wood chips nowadays. Boilers in output capacity range of 0.5-3 MW have become more and more general during recent years throughout Europe and in Finland. The combustion technique details vary a lot depending on the equipment manufacturer and boiler capacity. The practical experiences in Finland show that the boiler design is in relatively good level, but the natural conditions in the Nordic countries sometimes cause difficulties in sustaining homogeneous wood chip quality. Then, this causes drastic, quick changes in the combustion conditions. This leads to dirty smoke gases and disturbance in the heat transfer in the boiler convector. This study aims at presenting these practical factors affecting the heat transfer efficiency and some ideas to avoid the problems. Also the boiler plant technology aiming at combined heat and power production in small scale implies very efficient heat transfer. The most important single factor enabling or preventing efficient heat transfer in the boiler lies in forest sand then in wood chip storages. The wood chip quality consists of homogeneous moisture content, particle size and energy content. If these factors alter uncontrollably, this causes: temperature decrease on the grate and in the flame; increase in the smoke gas flow due to increased vapour content; increased impurities in the smoke gas. These all sakes cause major contamination of the heat exchanger and thus decrease in the heat transfer efficiency. Also some technically critical details can be pointed out. Among others, these are: old-fashioned, slowly and roughly reacting automation and combustion adjustment; primary and secondary combustion air feed division and points; boiler vacuum control; combustion chamber structure and amount of masonry. Wood chip boiler heat transfer efficiency can be improved by answering to above mentioned sakes. Absolutely the most important thing is to train the forest fuel production


    Directory of Open Access Journals (Sweden)

    O. M. Pshinko


    Full Text Available Purpose. The paper analyses the possibility and terms of increasing the efficiency of heating and ventilation systems of public buildings at the present stage of development and the specific climatic conditions of Ukraine. The main purpose is to develop specific measures for public buildings, which will lead to a significant reduction in energy costs for heating and air conditioning system. The example is similar system of DNURT compact campus, which is heated with its own autonomous boiler that uses natural gas. Methodology. The statistical heat loss analysis for the last 5 years allows defining the types and calculating the heat loss values for specific conditions. These losses are compared with those in the world practice and based on the comparison and analysis of the current system there are offered the ways to reduce the heat loss values through the use of various technical and organizational methods.The paper also proposes involvement for this purpose of secondary and alternative energy sources. The secondary energy resources include the heat that is emitted by people and that coming out with the air during ventilation of buildings. The renewable sources include solar and geothermal energy. To enhance the heat transfer medium temperature capacity it is proposed to use the heat pumps. Findings. The maximum possible use of the proposed measures and implementation of rational schematic and engineering solutions for heat and hot water supply systems cam reduce the energy loss for heating and hot water by 30-35%. Originality. The paper for the first time proposed the use of new integrated approaches to maintain the desired heat balance in the winter period, as well as the new schematic solutions for heating and ventilation systems, both in winter and in summer, based on the use of heat pumps and secondary energy resources. Practical value. The introduction of the proposed schematic solutions and approaches demand relatively small capital

  20. Efficient heat generation in large-area graphene films by electromagnetic wave absorption (United States)

    Kang, Sangmin; Choi, Haehyun; Lee, Soo Bin; Park, Seong Chae; Park, Jong Bo; Lee, Sangkyu; Kim, Youngsoo; Hong, Byung Hee


    Graphene has been intensively studied due to its outstanding electrical and thermal properties. Recently, it was found that the heat generation by Joule heating of graphene is limited by the conductivity of graphene. Here we suggest an alternative method to generate heat on a large-area graphene film more efficiently by utilizing the unique electromagnetic (EM) wave absorption property of graphene. The EM wave induces an oscillating magnetic moment generated by the orbital motion of moving electrons, which efficiently absorbs the EM energy and dissipate it as a thermal energy. In this case, the mobility of electron is more important than the conductivity, because the EM-induced diamagnetic moment is directly proportional to the speed of electron in an orbital motion. To control the charge carrier mobility of graphene we functionalized substrates with self-assembled monolayers (SAM). As the result, we find that the graphene showing the Dirac voltage close to zero can be more efficiently heated by EM waves. In addition, the temperature gradient also depends on the number of graphene. We expect that the efficient and fast heating of graphene films by EM waves can be utilized for smart heating windows and defogging windshields.

  1. Absorption efficiency and heating kinetics of nanoparticles in the RF range for selective nanotherapy of cancer. (United States)

    Letfullin, Renat R; Letfullin, Alla R; George, Thomas F


    Radio-frequency (RF) waves have an excellent ability to penetrate into the human body, giving a great opportunity to activate/heat nanoparticles delivered inside the body as a contrast agent for diagnosis and treatment purposes. However the heating of nanoparticles in the RF range of the spectrum is controversial in the research community because of the low power load of RF waves and low absorption of nanoparticles in the RF range. This study uses a phenomenological approach to estimate the absorption efficiency of metal and dielectric nanoparticles in the RF range through a study of heating kinetics of those particles in radio wave field. We also discuss the specific features of heating kinetics of nanoparticles, such as a short time scale for heating and cooling of nanoparticles in a liquid biological environment, and the effect of the radiation field structure on the heating kinetics by single-pulse and multipulse RF radiation. In this study a phenomenological approach was applied to estimate the absorption efficiency of radiofrequency radiation (RF) by metal and dielectric nanoparticles. Such nanoparticles can be designed and used for therapeutic purposes, like for localized heating and to activate nanoparticles by RF. The authors also discuss the differences in heating kinetics using single-pulse and multi-pulse RF radiation. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Fan cycling strategies and heat pipe heat exchangers provide energy efficient dehumidification

    Energy Technology Data Exchange (ETDEWEB)

    Shirey, D.B. III [Florida Solar Energy Center, Cape Canaveral, FL (United States)


    This article describes two methods to reduce energy consumption and peak demand in buildings that require humidity control that were demonstrated at the Salvador Dali Museum in St. Petersburg, Florida. The first method centered on alternative indoor fan cycling strategies and the second method involved the use of heat pipe heat exchangers. Both approaches increased the dehumidification performance of the existing air-conditioning systems and provided substantial savings. Simple, low cost alternative fan cycling strategies were used. When possible, auto fan control replaced constant fan operation to avoid excess fan energy consumption, ventilation load and compressor operation. The alternative fan control strategies reduced indoor humidity fluctuations in all zones, and significantly reduced overall humidity levels in the museum lobby and storage area. An HPHX was installed within one of the two gallery RTUs to improve the unit`s dehumidification performance. The passive HPHX significantly reduced electric reheat and compressor operation while maintaining the precise temperature and humidity requirements within the gallery. The second gallery RTU now operates primarily as a back-up unit to the heat pipe-assisted air-conditioning unit.

  3. High-efficiency heat pump technology using metal hydrides (eco-energy city project)

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Y.; Harada, T.; Niikura, J.; Yamamoto, Y.; Suzuki, J. [Human Environmental Systems Development Center, Matsushita Electric Industrial Co., Ltd., Moriguchi, Osaka (Japan); Gamo, T. [Corporate Environmental Affairs Div., Matsushita Electric Industrial Co., Ltd., Kadoma, Osaka (Japan)


    Metal hybrides are effective materials for utilizing hydrogen as a clean energy medium. That is, when the metal hydrides absorb or desorb the hydrogen, a large heat output of reaction occurs. So, the metal hydrides can be applied to a heat pump. We have researched on a high efficiency heat pump technology using their metal hydrides. In this report, a double effect type metal hydride heat pump configuration is described in which the waste heat of 160 C is recovered in a factory cite and transported to areas far distant from the industrial district. In the heat recovery unit, a low pressure hydrogen is converted into highly effective high pressure hydrogen by applying the metal hydrides. Other metal hydrides perform the parts of heating by absorbing the hydrogen and cooling by desorbing the hydrogen in the heat supply unit. One unit scale of the system is 3 kW class as the sum of heating and cooling. This system using the hydrogen absorbing alloy also has good energy storage characteristics and ambient hydrogen pressure self-safety control ability. Furthermore, this heating and cooling heat supply system is not harmful to the natural environment because it is a chlorofluorocarbon-free, and low noise type system. We have developed in the following element technologies to attain the above purposes, that is development of hydrogen absorbing alloys with high heat outputs and technologies to construct the heat pump system. This study is proceeded at present as one of the programs in New Sunshine Project, which aims for development of ingenious energy utilization technology to achieve reduction of primary energy consumption with keeping cultural and wealthy life and preventing deterioration of global environment. (orig.)

  4. On the development of an innovative gas-fired heating appliance based on a zeolite-water adsorption heat pump; system description and seasonal gas utilization efficiency

    International Nuclear Information System (INIS)

    Dawoud, Belal


    The main objective of this work is to introduce an innovative hybrid heating appliance incorporating a gas condensing boiler and a zeolite-water adsorption heat pump. The condensing boiler is applied to drive the zeolite-water heat pump for the heating base-load and to assist the heat pump in the so called “mixed operation” mode, in which both the heat pump and the condensing boiler are working in series to cover medium heating demands. Peak heating demands are covered by the condensing boiler in the so called “direct heating” mode. The three operation modes of the hybrid heating appliance have been technically described. In addition, the laboratory test conditions for estimating the seasonal heating performance according to the German Guideline VDI 4650-2 have been introduced. For both heating systems 35/28 °C and 55/45 °C, which represent the typical operating conditions of floor and high temperature radiating heating systems in Europe, seasonal heating gas utilization efficiencies of 1.34 and 1.26 have been measured, respectively with a ground heat source. In two field test installations in one-family houses in Germany, the introduced heating appliance showed 27% more seasonal gas utilization efficiency for heating and domestic hot water production, which is equivalent to a CO 2 -emission reduction of 20% compared to the gas condensing boiler technology

  5. Methods of Assessing the Efficiency of Cogeneration of Electricity and Heat

    Directory of Open Access Journals (Sweden)

    Postolaty V.M.


    Full Text Available A method that allows calculating the primary energy savings of fuel cogeneration of electricity and heat as compared to separate methods produce the same amount of these types of energy. An analytic expression relating the energy consumption of fuel for production of electricity and heat, taking into account the efficiency with the technologies of production of electricity and heat separately, and the total efficiency when these types of energy are in cogeneration. The results are illustrated by the example. Basing on these results it is recommended to amend the Law on thermal energy and cogeneration of electricity and heat concerning the methodologies for calculating performance of these types of energy cogeneration.

  6. Heat transfer efficiency evaluation for outward and inward multi-flame-hole gas burner (United States)

    Morita, Shin-ichi; Hayamizu, Yasutaka; Katayama, Takashi; Inaba, Hideo


    The purpose of this study is to understand the factor that influence the heating efficiency of the outward and inward multi-hole gas burner. The flame-hole angle and the distance from flame hole to heating object are chosen as the experimental parameters. The measurement of the flame temperature distribution is carried out on each experimental condition. The observation of combustion flame, by the Schlieren method, is done from the purpose to understand the combustion phenomenon on the heating efficiency. LPG (Liquefied petroleum gas) is used for the test fuel gas. The compositions of LPG are propane 97.5vol%, butane 0.2vol% and methane + ethylene 2.3vol%. The optimum ranges of the flame-hole angle and the distance from flame hole to heating object are clarified. The experimental correlation equations for the outward and inward multi-flame-hole gas burner are proposed.

  7. Solutions for Energy Efficient and Sustainable Heating of Ventilation Air: A Review

    Directory of Open Access Journals (Sweden)

    A. Žandeckis


    Full Text Available A high energy efficiency and sustainability standards defined by modern society and legislation requires solutions in the form of complex integrated systems. The scope of this work is to provide a review on technologies and methods for the heating of ventilation air as a key aspect for high energy and environmental performance of buildings located in a cold climate. The results of this work are more relevant in the buildings where space heating consumes a significant part of the energy balance of a building, and air exchange is arranged in an organized manner. A proper design and control strategy, heat recovery, the use of renewable energy sources, and waste heat are the main aspects which must be considered for efficient and sustainable ventilation. This work focuses on these aspects. Air conditioning is not in the scope of this study.

  8. Development of an Efficient Micro-Heat Exchanger: The Integration of Design Processing and Testing (United States)


    residual stress is contour method if the sample can be cleanly broken (brittle). We could possibly ABAQUS Python scripting interface to mesh actual part... Structure (b) Fabricated Heat Exchanger Figure 31: Another Configuration of Heat Exchanger 4. Summary Being able to micro -configure a ceramic material will...COVERED (From - To) I Final Report 01 Dec 2001 - 30 Nov 2005 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Development of an Efficient Micro -Heal Exhanger

  9. Efficiency of a fin with convective cooling at variable parameters of heat exchange

    International Nuclear Information System (INIS)

    Kurganov, V.A.


    The analysis of the effect of changes in the temperature by the fin length on the efficiency of the fins with the convective cooling and the heat exchange coefficient of the cooling liquid, as well as on the dependence of the fin heat conductivity on the temperature, is carried out through the spline method. It is shown, that by high rates of the λ change the effect of its variability may be essential especially for long fins [ru

  10. The Misselhorn Cycle: Batch-Evaporation Process for Efficient Low-Temperature Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Moritz Gleinser


    Full Text Available The concept of the Misselhorn cycle is introduced as a power cycle that aims for efficient waste heat recovery of temperature sources below 100 °C. The basic idea shows advantages over a standard Organic Rankine Cycle (ORC in overall efficiency and utilization of the heat source. The main characteristic of this cycle is the use of at least three parallel batch evaporators instead of continuous heat exchangers. The operational phases of the evaporators are shifted so that there is always one vaporizer in discharge mode. A transient MATLAB® model (The MathWorks: Natick, MA, USA is used to simulate the achievable performance of the Misselhorn cycle. The calculations of the thermodynamic states of the system are based on the heat flux, the equations for energy conservation and the equations of state found in the NIST Standard Reference Database 23 (Reference Fluid Thermodynamic and Transport Properties - REFPROP, National Institute of Standards and Technology: Gaithersburg, MD, USA. In the isochoric batch evaporation, the pressure and the corresponding boiling temperature rise over time. With a gradually increasing boiling temperature, no pinch point limitation occurs. Furthermore, the heat source medium is passed through the evaporators in serial order to obtain a quasi-counter flow setup. It could be shown that these features offer the possibility to gain both high thermal efficiencies and an enhanced utilization of the heat source at the same time. A basic model with a fixed estimated heat transfer coefficient promises a possible system exergy efficiency of 44.4%, which is an increase of over 60% compared to a basic ORC with a system exergy efficiency of only 26.8%.

  11. High Efficiency, Low Cost Parabolic Dish System for Cogeneration of Electricity and Heat (United States)

    Chayet, Haim; Lozovsky, Ilan; Kost, Ori; Loeckenhoff, Ruediger; Rasch, Klaus-Dieter


    Highly efficient combined heat and power generating system based on CPV technology using unique dish design consisting of multiple simple flat mirrors mounted on a plastic parabolic surface. The dish of total aperture area of 11 m2 focuses 10.3 kWp onto a heat and electricity generating receiver. The receiver comprises a water cooled, dense triple junction cell array of 176 cm2 aperture area. A unique arrangement of the cells compensates for the non-uniformity of the reflected flux. Depending on the flow rate, the temperature of the hot water can be adjusted to suit from temperatures for domestic use, to temperatures suited for process heat. The output of 2.3 kWp electrical and 5.5 kWp thermal power from one dish system represent 20 to 21% electrical and 50% thermal conversion efficiency adding to 70% overall system efficiency.

  12. Control apparatus and method for efficiently heating a fuel processor in a fuel cell system (United States)

    Doan, Tien M.; Clingerman, Bruce J.


    A control apparatus and method for efficiently controlling the amount of heat generated by a fuel cell processor in a fuel cell system by determining a temperature error between actual and desired fuel processor temperatures. The temperature error is converted to a combustor fuel injector command signal or a heat dump valve position command signal depending upon the type of temperature error. Logic controls are responsive to the combustor fuel injector command signals and the heat dump valve position command signal to prevent the combustor fuel injector command signal from being generated if the heat dump valve is opened or, alternately, from preventing the heat dump valve position command signal from being generated if the combustor fuel injector is opened.

  13. Thermal substitution and aerobic efficiency: measuring and predicting effects of heat balance on endotherm diving energetics. (United States)

    Lovvorn, J R


    For diving endotherms, modelling costs of locomotion as a function of prey dispersion requires estimates of the costs of diving to different depths. One approach is to estimate the physical costs of locomotion (Pmech) with biomechanical models and to convert those estimates to chemical energy needs by an aerobic efficiency (eta=Pmech/Vo2) based on oxygen consumption (Vo2) in captive animals. Variations in eta with temperature depend partly on thermal substitution, whereby heat from the inefficiency of exercising muscles or the heat increment of feeding (HIF) can substitute for thermogenesis. However, measurements of substitution have ranged from lack of detection to nearly complete use of exercise heat or HIF. This inconsistency may reflect (i) problems in methods of calculating substitution, (ii) confounding mechanisms of thermoregulatory control, or (iii) varying conditions that affect heat balance and allow substitution to be expressed. At present, understanding of how heat generation is regulated, and how heat is transported among tissues during exercise, digestion, thermal challenge and breath holding, is inadequate for predicting substitution and aerobic efficiencies without direct measurements for conditions of interest. Confirming that work rates during exercise are generally conserved, and identifying temperatures at those work rates below which shivering begins, may allow better prediction of aerobic efficiencies for ecological models.

  14. Efficiency Growth of Combined-cycle Cogeneration Plant with the Heat Supply System

    Directory of Open Access Journals (Sweden)

    Denysova Alla


    Full Text Available Energy efficiency of modern technologies of the combined production of heat and electricity and ways of energy saving on base of recycling secondary energy sources has been estimated. It is shown that the most effective for cogeneration are combined-cycle plants. The rational scheme of interaction of combined-cycle cogeneration plant with heat supply system has been offered. Theoretical bases of interaction of main installation with a contour of heat and hot water supply system has been developed. Numerical modeling of temperature parameters and the analysis of results of numerical modeling has been executed. The technology of increase of energy efficiency of installations on base of recycling heat is offered. Increase of effectiveness of system is achieved due to full use of heat and reduction of losses to environment. It is established, that the rational scheme of interaction of combined-cycle cogeneration plant with heat supply system allows increasing energy efficiency on 2 % that corresponds to economy of fuel 3 %.

  15. Achieving the classical Carnot efficiency in a strongly coupled quantum heat engine (United States)

    Xu, Y. Y.; Chen, B.; Liu, J.


    Generally, the efficiency of a heat engine strongly coupled with a heat bath is less than the classical Carnot efficiency. Through a model-independent method, we show that the classical Carnot efficiency is achieved in a strongly coupled quantum heat engine. First, we present the first law of quantum thermodynamics in strong coupling. Then, we show how to achieve the Carnot cycle and the classical Carnot efficiency at strong coupling. We find that this classical Carnot efficiency stems from the fact that the heat released in a nonequilibrium process is balanced by the absorbed heat. We also analyze the restrictions in the achievement of the Carnot cycle. The first restriction is that there must be two corresponding intervals of the controllable parameter in which the corresponding entropies of the work substance at the hot and cold temperatures are equal, and the second is that the entropy of the initial and final states in a nonequilibrium process must be equal. Through these restrictions, we obtain the positive work conditions, including the usual one in which the hot temperature should be higher than the cold, and a new one in which there must be an entropy interval at the hot temperature overlapping that at the cold. We demonstrate our result through a paradigmatic model—a two-level system in which a work substance strongly interacts with a heat bath. In this model, we find that the efficiency may abruptly decrease to zero due to the first restriction, and that the second restriction results in the control scheme becoming complex.

  16. Energy-efficiency in inductive heating of forging ingots; Energieeffizienz bei der induktiven Erwaermung von Schmiedebloecken

    Energy Technology Data Exchange (ETDEWEB)

    Padberg, Michael; Doetsch, Erwin [ABP Induction Systems, Dortmund (Germany)


    The continuously increasing importance of the CO{sub 2} balance and of conservation of resources is resulting in ever greater demands for high energy-efficiency in the process used for heating of forging ingots. Plant and process engineering play roles of parallel significance in the fulfillment of these requirements, and this article focuses on both in equal degree. The shares of the individual components in the overall energy consumption of an induction heating installation are therefore firstly determined, and their respective potentials for optimization then discussed. The quality of the heating process itself, and its optimum design for reduction of energy consumption, are then examined. (orig.)

  17. High efficient ammonia heat pump system for industrial process water using the ISEC concept. Part 1

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus Damgaard; Madsen, C.; Elmegaard, Brian


    The purpose of the Isolated System Energy Charging (ISEC) is to provide a high-efficient ammonia heat pump system for hot water production. The ISEC concept uses two storage tanks for the water, one discharged and one charged. The charged tank is used for the industrial process while the discharged...... tank, is charging. Charging is done by circulating the water in the tank through the condenser several times and thereby gradually heats the water. This result in a lower condensing temperature than if the water was heated in one step. A dynamic model of the system, implemented in Dymola, is used...

  18. Experimental evaluation of energy efficiency in a gas-heated self-contained steam jacketed kettle (United States)

    Manrique, V.; García, L.; Alfonso, J.


    Gas Technological Development Center (CDT de GAS) has developed a new gas-heated self-contained steam jacketed kettle as a solution for temperature-controlled cooking of pulp fruit in the Colombian traditional candy-making industry. This initiative seeks to contribute to the promotion of natural gas as a cleaner and more efficient alternative to traditional fuels such as wood and coal in the Andean countries. Prototype follows the operational and safety rules provided by international and local standards: ASTM-F1602, ASME (section VIII, division 1), and NTC-4082. This paper presents the methodology, experimental setup and results obtained during the performance tests for heating efficiency evaluation of the kettle, according to the ASTM-F1785 standard, and the estimation of measurement uncertainty according to GUM method. The heating efficiency rate for this new prototype is higher to the convectional and commercial models of gas heated self-contained steam jacketed kettle. The results showed a heating efficiency of 63.83% ± 1.66% (k=2), whereas the emission of CO and NOX in stack gases was under the regulate limits for natural gas equipment.

  19. The universal power and efficiency characteristics for irreversible reciprocating heat engine cycles

    CERN Document Server

    Qin Xiao Yong; Sun Feng Rui; Wu Chih


    The performance of irreversible reciprocating heat engine cycles with heat transfer loss and friction-like term loss is analysed using finite-time thermodynamics. The universal relations between the power output and the compression ratio, between the thermal efficiency and the compression ratio, and the optimal relation between power output and the efficiency of the cycles are derived. Moreover, analysis and optimization of the model were carried out in order to investigate the effect of cycle processes on the performance of the cycle using numerical examples. The results obtained herein include the performance characteristics of irreversible reciprocating Diesel, Otto, Atkinson and Brayton cycles.

  20. Crust formation and its effect on the molten pool coolability

    Energy Technology Data Exchange (ETDEWEB)

    Park, R.J.; Lee, S.J.; Sim, S.K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    Experimental and analytical studies of the crust formation and its effect on the molten pool coolability have been performed to examine the crust formation process as a function of boundary temperatures as well as to investigate heat transfer characteristics between molten pool and overlying water in order to evaluate coolability of the molten pool. The experimental test results have shown that the surface temperature of the bottom plate is a dominant parameter in the crust formation process of the molten pool. It is also found that the crust thickness of the case with direct coolant injection into the molten pool is greater than that of the case with a heat exchanger. Increasing mass flow rate of direct coolant injection to the molten pool does not affect the temperature of molten pool after the crust has been formed in the molten pool because the crust behaves as a thermal barrier. The Nusselt number between the molten pool and the coolant of the case with no crust formation is greater than that of the case with crust formation. The results of FLOW-3D analyses have shown that the temperature distribution contributes to the crust formation process due to Rayleigh-Benard natural convection flow.

  1. Improving Geothermal Heat Pump Air Conditioning Efficiency with Wintertime Cooling using Seasonal Thermal Energy Storage (STES). Application Manual (United States)


    APPLICATION MANUAL Improving Geothermal Heat Pump Air Conditioning Efficiency with Wintertime Cooling using Seasonal Thermal Energy Storage...manual is to describe the use of the Seasonal Thermal Energy Storage (STES) technology, particularly through the employment of wintertime cooling...application projects to increase energy efficiency and occupant comfort. Seasonal Thermal Energy Storage (STES) technology, energy efficiency, geothermal heat

  2. Economical Efficiency of Combined Cooling Heating and Power Systems Based on an Enthalpy Method

    Directory of Open Access Journals (Sweden)

    Yan Xu


    Full Text Available As the living standards of Chinese people have been improving, the energy demand for cooling and heating, mainly in the form of electricity, has also expanded. Since an integrated cooling, heating and power supply system (CCHP will serve this demand better, the government is now attaching more importance to the application of CCHP energy systems. Based on the characteristics of the combined cooling heating and power supply system, and the method of levelized cost of energy, two calculation methods for the evaluation of the economical efficiency of the system are employed when the energy production in the system is dealt with from the perspective of exergy. According to the first method, fuel costs account for about 75% of the total cost. In the second method, the profits from heating and cooling are converted to fuel costs, resulting in a significant reduction of fuel costs, accounting for 60% of the total cost. Then the heating and cooling parameters of gas turbine exhaust, heat recovery boiler, lithium-bromide heat-cooler and commercial tariff of provincial capitals were set as benchmark based on geographic differences among provinces, and the economical efficiency of combined cooling heating and power systems in each province were evaluated. The results shows that the combined cooling heating and power system is economical in the developed areas of central and eastern China, especially in Hubei and Zhejiang provinces, while in other regions it is not. The sensitivity analysis was also made on related influencing factors of fuel cost, demand intensity in heating and cooling energy, and bank loans ratio. The analysis shows that the levelized cost of energy of combined cooling heating and power systems is very sensitive to exergy consumption and fuel costs. When the consumption of heating and cooling energy increases, the unit cost decreases by 0.1 yuan/kWh, and when the on-grid power ratio decreases by 20%, the cost may increase by 0.1 yuan

  3. Efficiency gains of photovoltaic system using latent heat thermal energy storage

    NARCIS (Netherlands)

    Tan, Lippong; Date, Abhijit; Fernandes, Gabriel; Singh, Baljit; Ganguly, Sayantan

    This paper presents experimental assessments of the thermal and electrical performance of photovoltaic (PV) system by comparing the latent heat-cooled PV panel with the naturally-cooled equivalent. It is commonly known that the energy conversion efficiency of the PV cells declines with the increment

  4. Energy Efficiency Modelling of Residential Air Source Heat Pump Water Heater

    Directory of Open Access Journals (Sweden)

    Cong Toan Tran


    Full Text Available The heat pump water heater is one of the most energy efficient technologies for heating water for household use. The present work proposes a simplified model of coefficient of performance and examines its predictive capability. The model is based on polynomial functions where the variables are temperatures and the coefficients are derived from the Australian standard test data, using regression technics. The model enables to estimate the coefficient of performance of the same heat pump water heater under other test standards (i.e. US, Japanese, European and Korean standards. The resulting estimations over a heat-up phase and a full test cycle including a draw off pattern are in close agreement with the measured data. Thus the model allows manufacturers to avoid the need to carry out physical tests for some standards and to reduce product cost. The limitations of the methodology proposed are also discussed.

  5. Playing Hot and Cold: How Can Russian Heat Policy Find Its Way Toward Energy Efficiency?

    Energy Technology Data Exchange (ETDEWEB)

    Roshchanka, Volha; Evans, Meredydd


    The Russian district heating has a large energy-saving potential, and, therefore, need for investments. The scale of needed investments is significant: the government estimates that 70 percent of the district heating infrastructure needs replacement or maintenance, a reflection of decades of under investment. Government budgets will be unable to cover them, and iInvolvingement ofthe private industry will be critical to attracting the necessary investementis necessary. For private parties to invest in district heating facilities across Russia, and not only in pockets of already successful enterprises, regulators have to develop a comprehensive policy that works district heating systems under various conditionscost-reflective tariffs, metering, incentives for efficiency and social support for the neediest (instead of subsidies for all).

  6. Exergy efficiency enhancement of MSF desalination by heat recovery from hot distillate water stages

    International Nuclear Information System (INIS)

    Al-Weshahi, Mohammed A.; Anderson, Alexander; Tian, Guohong


    This detailed exergy analysis of a 3800 m 3 /h Multi-Stage Flash (MSF) desalination plant is based on the latest published thermodynamics properties of water and seawater. The parameters of the study were extracted from a validated model of MSF desalination using IPSEpro software. The results confirmed that the overall exergy efficiency of the unit is lower than would be desirable at only 5.8%. Exergy inputs were destroyed by 55%, 17%, 10%, 4.3%, and 14% respectively, in the heat recovery stages, brine heater, heat rejection stages, pumps and brine streams disposal. Moreover, the detail of the study showed that the lowest exergy destruction occurs in the first stage, increasing gradually in heat recovery stages and sharply in heat rejection stages. The study concludes that recovering the heat from the hot distillate water stages can improve unit exergy efficiency from its low 5.8% to a more economical 14%, with the hot water parameters suitable for powering other thermal systems such as absorption chiller and multi-effect desalination

  7. Improvement of proton exchange membrane fuel cell overall efficiency by integrating heat-to-electricity conversion (United States)

    Xie, Chungang; Wang, Shuxin; Zhang, Lianhong; Hu, S. Jack

    Proton exchange membrane fuel cells (PEMFCs) have shown to be well suited for distributed power generation due to their excellent performance. However, a PEMFC produces a considerable amount of heat in the process of electrochemical reaction. It is desirable to use thermal energy for electricity generation in addition to heating applications. Based on the operating characteristics of a PEMFC, an advanced thermal energy conversion system using "ocean thermal energy conversion" (OTEC) technology is applied to exploit the thermal energy of the PEMFC for electricity generation. Through this combination of technology, this unique PEMFC power plant not only achieves the combined heat and power efficiency, but also adequately utilizes heat to generate more valuable electricity. Exergy analysis illustrates the improvement of overall efficiency and energy flow distribution in the power plant. Analytical results show that the overall efficiency of the PEMFC is increased by 0.4-2.3% due to the thermal energy conversion (TEC) system. It is also evident that the PEMFC should operate within the optimal load range by balancing the design parameters of the PEMFC and of the TEC system.

  8. Improving the thermal efficiency of a jaggery production module using a fire-tube heat exchanger. (United States)

    La Madrid, Raul; Orbegoso, Elder Mendoza; Saavedra, Rafael; Marcelo, Daniel


    Jaggery is a product obtained after heating and evaporation processes have been applied to sugar cane juice via the addition of thermal energy, followed by the crystallisation process through mechanical agitation. At present, jaggery production uses furnaces and pans that are designed empirically based on trial and error procedures, which results in low ranges of thermal efficiency operation. To rectify these deficiencies, this study proposes the use of fire-tube pans to increase heat transfer from the flue gases to the sugar cane juice. With the aim of increasing the thermal efficiency of a jaggery installation, a computational fluid dynamic (CFD)-based model was used as a numerical tool to design a fire-tube pan that would replace the existing finned flat pan. For this purpose, the original configuration of the jaggery furnace was simulated via a pre-validated CFD model in order to calculate its current thermal performance. Then, the newly-designed fire-tube pan was virtually replaced in the jaggery furnace with the aim of numerically estimating the thermal performance at the same operating conditions. A comparison of both simulations highlighted the growth of the heat transfer rate at around 105% in the heating/evaporation processes when the fire-tube pan replaced the original finned flat pan. This enhancement impacted the jaggery production installation, whereby the thermal efficiency of the installation increased from 31.4% to 42.8%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Efficient Solar-Thermal Energy Harvest Driven by Interfacial Plasmonic Heating-Assisted Evaporation. (United States)

    Chang, Chao; Yang, Chao; Liu, Yanming; Tao, Peng; Song, Chengyi; Shang, Wen; Wu, Jianbo; Deng, Tao


    The plasmonic heating effect of noble nanoparticles has recently received tremendous attention for various important applications. Herein, we report the utilization of interfacial plasmonic heating-assisted evaporation for efficient and facile solar-thermal energy harvest. An airlaid paper-supported gold nanoparticle thin film was placed at the thermal energy conversion region within a sealed chamber to convert solar energy into thermal energy. The generated thermal energy instantly vaporizes the water underneath into hot vapors that quickly diffuse to the thermal energy release region of the chamber to condense into liquids and release the collected thermal energy. The condensed water automatically flows back to the thermal energy conversion region under the capillary force from the hydrophilic copper mesh. Such an approach simultaneously realizes efficient solar-to-thermal energy conversion and rapid transportation of converted thermal energy to target application terminals. Compared to conventional external photothermal conversion design, the solar-thermal harvesting device driven by the internal plasmonic heating effect has reduced the overall thermal resistance by more than 50% and has demonstrated more than 25% improvement of solar water heating efficiency.

  10. Magnetic nanowires and hyperthermia: How geometry and material affect heat production efficiency

    KAUST Repository

    Contreras, Maria F.


    Magnetic hyperthermia, which refers to the production of heat by magnetic nanostructures under an alternating magnetic field (AMF), has been previously investigated with superparamagnetic nanobeads as a cancer therapy method. Magnetic nanowires (NWs) used in hyperthermia can be very promising, as it has been shown that they have a larger magnetic moment per unit of volume compared to the nanobeads. Moreover, Fe NWs proved to have a higher heating efficiency compared to Fe nanobeads, when exposed to an AMF at the same concentration [1].

  11. High efficient ammonia heat pump system for industrial process water using the ISEC concept. Part 2

    DEFF Research Database (Denmark)

    Olesen, Martin F.; Madsen, Claus; Olsen, Lars


    The Isolated System Energy Charging (ISEC) concept allows for a high efficiency of a heat pump system for hot water production. The ISEC concept consists of two water storage tanks, one charged and one discharged. The charged tank is used for the industrial process, while the discharged tank is c...... modelling of the heat pump and tank system is performed (in continuation of Part I). The modelling is extended to include the system performance with different natural refrigerants and the influence of different types of compressors....

  12. Effect of Design Static Pressure Level on Energy Efficiency at Low Energy District Heating Systems

    DEFF Research Database (Denmark)

    Tol, Hakan; Svendsen, Svend


    Low-Energy District Heating (DH) systems with low-temperature operations, such as 55 °C in terms of supply and 25 °C in terms of return, were considered to be the 4th generation of the DH systems for the low-energy future with energy efficiencies focused to be achieved at newly built and existing...... buildings by the Danish building regulations. Therefore focus has been given to reduce the heat demand of the consumer site with integration of low-energy buildings, to be considered for new settlements and with renovation of existing buildings to low-energy class. The reduction of heat demand increases...... the ratio of heat loss from the DH network in comparison to the heat supplied to the district. In our former studies, the low-energy DH system was optimized with the aim of reducing the heat loss from the low-energy DH network in a certain limit of static pressure level of 10 bara. Thus, in this present...

  13. Energy efficiency improvement of dryer section heat recovery systems in paper machines - A case study

    International Nuclear Information System (INIS)

    Sivill, Leena; Ahtila, Pekka


    Modern paper machines are equipped with heat recovery systems that transfer heat from the humid exhaust air of the paper machine's dryer section to different process streams. As a result of process changes, the heat recovery systems may operate in conditions far from the original design point, creating a significant potential for energy efficiency improvement. In this paper we demonstrate this potential with a case study of three operating paper machines. Both operational and structural improvement opportunities are examined. Since the existing retrofit methodologies for heat exchanger networks can not be applied to cases with condensing air, we use thermodynamic simulation models presented earlier to assess the effects of possible changes on the existing heat recovery systems. In order to reduce the required processing time of the simulation models, only a limited number of pre-screened retrofit designs are considered. The pre-screening is carried out on the basis of guidelines presented earlier. The analysis in the case mill revealed savings of 110 GWh/a in process heat with profitable investments. According to the follow-up study, the investments carried out have resulted in 12% lower fuel use and 24% lower CO 2 emissions. The results imply that all operating paper machines should be similarly examined.

  14. Effects of heat stress on dynamic absorption process, tissue distribution and utilization efficiency of vitamin C in broilers

    International Nuclear Information System (INIS)

    Liu Guohua; Chen Guosheng; Cai Huiyi


    The experiment was conducted to determine the effects of heat stress on ascorbic acid nutritional physiology of broilers with radioisotope technology. 3 H-Vc was fed to broilers and then the blood, liver, kidney, breast muscle, and excreta were sampled to determine the dynamic absorption process, the tissue distribution and the utilization efficiency of vitamin C. The results indicated that the absorption, metabolism and mobilization of supplemented vitamin C in broilers with heat stress was faster than that in broilers without heat stress. However, the utilization efficiency of supplemented vitamin C in broilers with heat stress was not higher than that of broilers without heat stress

  15. 10 CFR 431.107 - Uniform test method for the measurement of energy efficiency of commercial heat pump water... (United States)


    ... 10 Energy 3 2010-01-01 2010-01-01 false Uniform test method for the measurement of energy efficiency of commercial heat pump water heaters. [Reserved] 431.107 Section 431.107 Energy DEPARTMENT OF....107 Uniform test method for the measurement of energy efficiency of commercial heat pump water heaters...

  16. Efficiency gains in Danish district heating. Is there anything to learn from benchmarking?

    Energy Technology Data Exchange (ETDEWEB)

    Munksgaard, Jesper; Pade, L.-L.; Fristrup, Peter


    Facing a market structure of independent heating systems and cost-of-service regulation the regulator considers ways to create incentives for increasing efficiency in heat production. One way is to implement benchmark regulation. The aim of this paper is twofold: (1) To investigate the potential for increasing productivity in Danish district heating production and (2) to examine whether benchmarking has a role to play. Using data envelopment analysis our analyses show that by assuming variable returns to scale a potential exists to reduce production costs by 5-27% depending on the portfolio of inputs and outputs included in the model. Further, our analyses show that the ranking of producers is much dependent on the combination of inputs and outputs included in the model. Therefore, great care should be taken when deciding on the appropriate model to be used when implementing benchmarking as a regulatory mean.

  17. Economic analysis of exergy efficiency based control strategy for geothermal district heating system

    International Nuclear Information System (INIS)

    Keçebaş, Ali; Yabanova, İsmail


    Highlights: • The ExEBCS for exergy efficiency maximization in real GDHS is economically evaluated. • The initial cost for ExEBCS is more expensive than that for old one by 6.33 kUS$/year. • The cost saving makes the ExEBCS profitable by up to 7% of annual energy saving. • This results in a short payback period of 3.8 years. • The use of newly ExEBCS in GDHSs is quite suitable. - Abstract: In this study, the exergy efficiency based control strategy (ExEBCS) for exergy efficiency maximization in geothermal district heating systems (GDHSs) is economically evaluated. As a real case study, the Afyon GDHS in the city of Afyonkarahisar/Turkey is considered. Its actual thermal data as of average weekly data are collected in heating seasons during the period 2006–2010 for artificial neural network (ANN) modeling. The ANN modeling of the Afyon GDHS is used as a test system to demonstrate the effectiveness and economic impact of the ExEBCS under various operating conditions. Then, the ExEBCS is evaluated economically in case of application to real Afyon GDHS of the ExEBCS. The results show that the initial cost for the ExEBCS is more expensive than that for the old one by 6.33 kUS$/year as a result of replacing automatic controller. The saving in heat production makes the ExEBCS profitable by up to 7% of annual energy saving as a result of the increase in the heat production by 88% when the control system is operated. This results in a short payback period of 3.8 years. This study confirms that the use of ExEBCS in district heating systems (especially GDHS) is quite suitable

  18. Enhancement of Heat-Recovery Steam-Gas Plant Efficiency at Expense of Steam Reheating Application

    Directory of Open Access Journals (Sweden)

    A. S. Grinchuk


    Full Text Available The paper considers a thermodynamic efficiency and peculiar features pertaining to realization of heat-recovery steam-gas plant schemes with steam reheating. Possible reserves of higher efficiency concerning plant economy and methods for achieving these goals are given in the paper. The author has made calculations for steam-gas plants of one-, two- and three-loop cycle of steam pressure. An analysis of the obtained results in respect of technical and economic indices and expediency of the application of corresponding plants in power engineering of the Republic of Belarus are presented in the paper.

  19. Exergy Analysis and Second Law Efficiency of a Regenerative Brayton Cycle with Isothermal Heat Addition

    Directory of Open Access Journals (Sweden)

    Naser M. Jubeh


    Full Text Available Abstract: The effect of two heat additions, rather than one, in a gas turbine engine is analyzed from the second law of thermodynamics point of view. A regenerative Brayton cycle model is used for this study, and compared with other models of Brayton cycle. All fluid friction losses in the compressor and turbine are quantified by an isentropic efficiency term. The effect of pressure ratio, turbine inlet temperature, ambient temperature, altitude, and altitude with variable ambient temperature on irreversibility "exergy destroyed" and second law efficiency was investigated and compared for all models. The results are given graphically with the appropriate discussion and conclusion.

  20. Relations between the efficiency, power and dissipation for linear irreversible heat engine at maximum trade-off figure of merit (United States)

    Iyyappan, I.; Ponmurugan, M.


    A trade of figure of merit (\\dotΩ ) criterion accounts the best compromise between the useful input energy and the lost input energy of the heat devices. When the heat engine is working at maximum \\dotΩ criterion its efficiency increases significantly from the efficiency at maximum power. We derive the general relations between the power, efficiency at maximum \\dotΩ criterion and minimum dissipation for the linear irreversible heat engine. The efficiency at maximum \\dotΩ criterion has the lower bound \

  1. An improved routine for the fast estimate of ion cyclotron heating efficiency in tokamak plasmas

    International Nuclear Information System (INIS)

    Brambilla, M.


    The subroutine ICEVAL for the rapid simulation of Ion Cyclotron Heating in tokamak plasmas is based on analytic estimates of the wave behaviour near resonances, and on drastic but reasonable simplifications of the real geometry. The subroutine has been rewritten to improve the model and to facilitate its use as input in transport codes. In the new version the influence of quasilinear minority heating on the damping efficiency is taken into account using the well-known Stix analytic approximation. Among other improvements are: a) the possibility of considering plasmas with more than two ion species; b) inclusion of Landau, Transit Time and collisional damping on the electrons non localised at resonances; c) better models for the antenna spectrum and for the construction of the power deposition profiles. The results of ICEVAL are compared in detail with those of the full-wave code FELICE for the case of Hydrogen minority heating in a Deuterium plasma; except for details which depend on the excitation of global eigenmodes, agreement is excellent. ICEVAL is also used to investigate the enhancement of the absorption efficiency due to quasilinear heating of the minority ions. The effect is a strongly non-linear function of the available power, and decreases rapidly with increasing concentration. For parameters typical of Asdex Upgrade plasmas, about 4 MW are required to produce a significant increase of the single-pass absorption at concentrations between 10 and 20%. (orig.)

  2. Performance investigation of a cogeneration plant with the efficient and compact heat recovery system

    KAUST Repository

    Myat, Aung


    This paper presents the performance investigation of a cogeneration plant equipped with an efficient waste heat recovery system. The proposed cogeneration system produces four types of useful energy namely: (i) electricity, (ii) steam, (iii) cooling and (iv) dehumidification. The proposed plant comprises a Capstone C30 micro-turbine which generates 24 kW of electricity, a compact and efficient waste heat recovery system and a host of waste heat activated devices namely (i) a steam generator, (ii) an absorption chiller, (iii) an adsorption chiller and (iv) a multi-bed desiccant dehumidifier. The numerical analysis for the host of waste heat recovery system and thermally activated devices using FORTRAN power station linked to powerful IMSL library is performed to investigate the performance of the overall system. A set of experiments, both part load and full load, of micro-turbine is conducted to examine the electricity generation and the exhaust gas temperature. It is observed that energy utilization factor (EUF) could achieve as high as 70% while Fuel Energy Saving Ratio (FESR) is found to be 28%.

  3. The Optimal Evaporation Temperature of Subcritical ORC Based on Second Law Efficiency for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Xu


    Full Text Available The subcritical Organic Rankine Cycle (ORC with 28 working fluids for waste heat recovery is discussed in this paper. The effects of the temperature of the waste heat, the critical temperature of working fluids and the pinch temperature difference in the evaporator on the optimal evaporation temperature (OET of the ORC have been investigated. The second law efficiency of the system is regarded as the objective function and the evaporation temperature is optimized by using the quadratic approximations method. The results show that the OET will appear for the temperature ranges investigated when the critical temperatures of working fluids are lower than the waste heat temperatures by 18 ± 5 K under the pinch temperature difference of 5 K in the evaporator. Additionally, the ORC always exhibits the OET when the pinch temperature difference in the evaporator is raised under the fixed waste heat temperature. The maximum second law efficiency will decrease with the increase of pinch temperature difference in the evaporator.

  4. Optimum efficiencies and phase change temperatures in latent heat storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Aceves-Saborio, S.; Nakamura, H. (Daido Inst. of Tech., Nagoya (Japan). Dept. of Mechanical Engineering); Reistad, G.M. (Oregon State Univ., Corvallis, OR (United States). Dept. of Mechanical Engineering)


    This paper presents an analysis of a class of latent heat storage systems (LHSS). The analysis is based on a lumped model (the basic model) that allows a broad class of LHSSs to be completely specified, with only two parameters and a set of operating temperatures, while still retaining the main thermodynamic aspects associated with its operation. Characterization of the performance in this manner permits the broad base application potential of such systems to be viewed. This modeling is in contrast to most studies to date, which employ many parameters to include details of specific systems, and therefore obscure, to a great extent, this broad-based application potential. The basic model is later modified in three ways to analyze operating conditions that either occur in practical units or are desirable for an improved operation of the units. The modifications include, first, the consideration of the LHSS as being formed by many independent phase-change material (PCM) capsules. Second, the possibility of having PCMs with different phase change temperatures filling the capsules. Third, the case when the PCM melts over a temperature range. The results indicate that the efficiency of the basic model represents a higher bound for the efficient operation of LHSSs with negligible sensible storage capacity, and a single PCM. Using multiple PCMs within a LHSS results in higher efficiencies. These efficiencies set higher bounds for efficiency of any sensible or latent heat storage system, and also represent the only possibility for reversible operation of LHSS.



    Umesh Kumar, Dr. A K Prasad, Sourabh Kumar Soni


    Based on the principles of heat integration, the present work investigates the design and operational modifications which can lead to efficient energy integration in an electric arc furnace being operated with direct reduction process. This process is one of the oldest and most widely applied processes amongst the commercially used process in India. For the purpose of energy integration stream data is extracted from the actual flow sheet of the plant, which consists of supply and target tempe...

  6. Fault zone architecture, San Jacinto fault zone, southern California: evidence for focused fluid flow and heat transfer in the shallow crust (United States)

    Morton, N.; Girty, G. H.; Rockwell, T. K.


    of a narrow, ephemeral hydrothermal circulation cell that dissipates heat generated from rupture events at deeper levels (> 4 km).

  7. Thermo-aerodynamic efficiency of non-circular ducts with vortex enhancement of heat exchange in different types of compact heat exchangers (United States)

    Vasilev, V. Ya; Nikiforova, S. A.


    Experimental studies of thermo-aerodynamic characteristics of non-circular ducts with discrete turbulators on walls and interrupted channels have confirmed the rational enhancement of convective heat transfer, in which the growth of heat transfer outstrips or equals the growth of aerodynamic losses. Determining the regularities of rational (energy-saving) enhancement of heat transfer and the proposed method for comparing the characteristics of smooth-channel (without enhancement) heat exchangers with effective analogs provide new results, confirming the high efficiency of vortex enhancement of convective heat transfer in non-circular ducts of plate-finned heat exchange surfaces. This allows creating heat exchangers with much smaller mass and volume for operation in energy-saving modes.

  8. Development of High Efficiency Carbon Dioxide Commercial Heat Pump Water Heater

    Energy Technology Data Exchange (ETDEWEB)

    Michael PETERSEN; Chad D. BOWERS; Stefan ELBEL; Pega HRNJAK


    Although heat pump water heaters are today widely accepted in both Japan and Europe, where energy costs are high and government incentives for their use exist, acceptance of such products in the US has been limited. While this trend is slowly changing with the introduction of heat pump water heaters into the residential market, but acceptance remains low in the commercial sector. The objective of the presented work is the development of a high efficiency R744 heat pump water heater for commercial applications with effective utilization of the cooling capability for air conditioning and/or refrigeration. The ultimate goal is to achieve total system COP of up to 8. This unit will be targeted at commercial use where some cooling load is typically needed year round, such as restaurants, hotels, nursing homes, and hospitals. This paper presents the performance results from the development of four R744 commercial heat pump water heater packages of approximately 35 kW and comparison to a commercially available baseline R134a unit of the same capacity and footprint. In addition, the influences of an internal heat exchanger and an enhanced evaporator on the system performance are described and recommendations are made for further improvements of the R744 system.

  9. Heating Changes Bio-Schwertmannite Microstructure and Arsenic(III Removal Efficiency

    Directory of Open Access Journals (Sweden)

    Xingxing Qiao


    Full Text Available Schwertmannite (Sch is an efficient adsorbent for arsenic(III removal from arsenic(III-contaminated groundwater. In this study, bio-schertmannite was synthesized in the presence of dissolved ferrous ions and Acidithiobacillus ferrooxidans LX5 in a culture media. Bio-synthesized Sch characteristics, such as total organic carbon (TOC, morphology, chemical functional groups, mineral phase, specific surface area, and pore volume were systematically studied after it was dried at 105 °C and then heated at 250–550 °C. Differences in arsenic(III removal efficiency between 105 °C dried-sch and 250–550 °C heated-sch also were investigated. The results showed that total organic carbon content in Sch and Sch weight gradually decreased when temperature increased from 105 °C to 350 °C. Sch partly transformed to another nanocrystalline or amorphous phase above 350 °C. The specific surface area of 250 °C heated-sch was 110.06 m2/g compared to 5.14 m2/g for the 105 °C dried-sch. Total pore volume of 105 °C dried-sch was 0.025 cm3/g with 32.0% mesopore and 68.0% macropore. However, total pore volume of 250 °C heated-mineral was 0.106 cm3/g with 23.6% micropore, 33.0% mesopore, and 43.4% macropore. The arsenic(III removal efficiency from an initial 1 mg/L arsenic(III solution (pH 7.5 was 25.1% when 0.25 g/L of 105 °C dried-sch was used as adsorbent. However, this efficiency increased to 93.0% when using 250 °C heated-sch as adsorbent. Finally, the highest efficiency for arsenic(III removal was obtained with sch-250 °C due to high amounts of sorption sites in agreement with the high specific surface area (SSA obtained for this sample.

  10. First and Second-Law Efficiency Analysis and ANN Prediction of a Diesel Cycle with Internal Irreversibility, Variable Specific Heats, Heat Loss, and Friction Considerations

    Directory of Open Access Journals (Sweden)

    M. M. Rashidi


    Full Text Available The variability of specific heats, internal irreversibility, heat and frictional losses are neglected in air-standard analysis for different internal combustion engine cycles. In this paper, the performance of an air-standard Diesel cycle with considerations of internal irreversibility described by using the compression and expansion efficiencies, variable specific heats, and losses due to heat transfer and friction is investigated by using finite-time thermodynamics. Artificial neural network (ANN is proposed for predicting the thermal efficiency and power output values versus the minimum and the maximum temperatures of the cycle and also the compression ratio. Results show that the first-law efficiency and the output power reach their maximum at a critical compression ratio for specific fixed parameters. The first-law efficiency increases as the heat leakage decreases; however the heat leakage has no direct effect on the output power. The results also show that irreversibilities have depressing effects on the performance of the cycle. Finally, a comparison between the results of the thermodynamic analysis and the ANN prediction shows a maximum difference of 0.181% and 0.194% in estimating the thermal efficiency and the output power. The obtained results in this paper can be useful for evaluating and improving the performance of practical Diesel engines.

  11. A method to determine stratification efficiency of thermal energy storage processes independently from storage heat losses

    DEFF Research Database (Denmark)

    Haller, M.Y.; Yazdanshenas, Eshagh; Andersen, Elsa


    A new method for the calculation of a stratification efficiency of thermal energy storages based on the second law of thermodynamics is presented. The biasing influence of heat losses is studied theoretically and experimentally. Theoretically, it does not make a difference if the stratification...... directly, and a tank-in-tank system whose outer tank is charged and the inner tank is discharged thereafter. The new method has a great potential for the comparison of the stratification efficiencies of thermal energy storages and storage components such as stratifying devices....... efficiency is calculated based on entropy balances or based on exergy balances. In practice, however, exergy balances are less affected by measurement uncertainties, whereas entropy balances can not be recommended if measurement uncertainties are not corrected in a way that the energy balance of the storage...

  12. Steam injection for heavy oil recovery: Modeling of wellbore heat efficiency and analysis of steam injection performance

    International Nuclear Information System (INIS)

    Gu, Hao; Cheng, Linsong; Huang, Shijun; Li, Bokai; Shen, Fei; Fang, Wenchao; Hu, Changhao


    Highlights: • A comprehensive mathematical model was established to estimate wellbore heat efficiency of steam injection wells. • A simplified approach of predicting steam pressure in wellbores was proposed. • High wellhead injection rate and wellhead steam quality can improve wellbore heat efficiency. • High wellbore heat efficiency does not necessarily mean good performance of heavy oil recovery. • Using excellent insulation materials is a good way to save water and fuels. - Abstract: The aims of this work are to present a comprehensive mathematical model for estimating wellbore heat efficiency and to analyze performance of steam injection for heavy oil recovery. In this paper, we firstly introduce steam injection process briefly. Secondly, a simplified approach of predicting steam pressure in wellbores is presented and a complete expression for steam quality is derived. More importantly, both direct and indirect methods are adopted to determine the wellbore heat efficiency. Then, the mathematical model is solved using an iterative technique. After the model is validated with measured field data, we study the effects of wellhead injection rate and wellhead steam quality on steam injection performance reflected in wellbores. Next, taking cyclic steam stimulation as an example, we analyze steam injection performance reflected in reservoirs with numerical reservoir simulation method. Finally, the significant role of improving wellbore heat efficiency in saving water and fuels is discussed in detail. The results indicate that we can improve the wellbore heat efficiency by enhancing wellhead injection rate or steam quality. However, high wellbore heat efficiency does not necessarily mean satisfactory steam injection performance reflected in reservoirs or good performance of heavy oil recovery. Moreover, the paper shows that using excellent insulation materials is a good way to save water and fuels due to enhancement of wellbore heat efficiency

  13. Experimental and numerical investigations of heat transfer and thermal efficiency of an infrared gas stove (United States)

    Charoenlerdchanya, A.; Rattanadecho, P.; Keangin, P.


    An infrared gas stove is a low-pressure gas stove type and it has higher thermal efficiency than the other domestic cooking stoves. This study considers the computationally determine water and air temperature distributions, water and air velocity distributions and thermal efficiency of the infrared gas stove. The goal of this work is to investigate the effect of various pot diameters i.e. 220 mm, 240 mm and 260 mm on the water and air temperature distributions, water and air velocity distributions and thermal efficiency of the infrared gas stove. The time-dependent heat transfer equation involving diffusion and convection coupled with the time-dependent fluid dynamic equation is implemented and is solved by using the finite element method (FEM). The computer simulation study is validated with an experimental study, which is use standard experiment by LPG test for low-pressure gas stove in households (TIS No. 2312-2549). The findings revealed that the water and air temperature distributions increase with greater heating time, which varies with the three different pot diameters (220 mm, 240 mm and 260 mm). Similarly, the greater heating time, the water and air velocity distributions increase that vary by pot diameters (220, 240 and 260 mm). The maximum water temperature in the case of pot diameter of 220 mm is higher than the maximum water velocity in the case of pot diameters of 240 mm and 260 mm, respectively. However, the maximum air temperature in the case of pot diameter of 260 mm is higher than the maximum water velocity in the case of pot diameters of 240 mm and 220 mm, respectively. The obtained results may provide a basis for improving the energy efficiency of infrared gas stoves and other equipment, including helping to reduce energy consumption.

  14. The energy efficiency ratio of heat storage in one shell-and-one tube phase change thermal energy storage unit

    International Nuclear Information System (INIS)

    Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling


    Highlights: • A parameter to indicate the energy efficiency ratio of PCTES units is defined. • The characteristics of the energy efficiency ratio of PCTES units are reported. • A combined parameter of the physical properties of the working mediums is found. • Some implications of the energy efficiency ratio in design of PCTES units are analyzed. - Abstract: From aspect of energy consuming to pump heat transfer fluid, there is no sound basis on which to create an optimum design of a thermal energy storage unit. Thus, it is necessary to develop a parameter to indicate the energy efficiency of such unit. This paper firstly defines a parameter that indicates the ratio of heat storage of phase change thermal energy storage unit to energy consumed in pumping heat transfer fluid, which is called the energy efficiency ratio, then numerically investigates the characteristics of this parameter. The results show that the energy efficiency ratio can clearly indicate the energy efficiency of a phase change thermal energy storage unit. When the fluid flow of a heat transfer fluid is in a laminar state, the energy efficiency ratio is larger than in a turbulent state. The energy efficiency ratio of a shell-and-tube phase change thermal energy storage unit is more sensitive to the outer tube diameter. Under the same working conditions, within the heat transfer fluids studied, the heat storage property of the phase change thermal energy storage unit is best for water as heat transfer fluid. A combined parameter is found to indicate the effects of both the physical properties of phase change material and heat transfer fluid on the energy efficiency ratio

  15. Additive Manufacturing for Cost Efficient Production of Compact Ceramic Heat Exchangers and Recuperators

    Energy Technology Data Exchange (ETDEWEB)

    Shulman, Holly [Ceralink Incorporated, Troy, NY (United States); Ross, Nicole [Ceralink Incorporated, Troy, NY (United States)


    An additive manufacture technique known as laminated object manufacturing (LOM) was used to fabricate compact ceramic heat exchanger prototypes. LOM uses precision CO2 laser cutting of ceramic green tapes, which are then precision stacked to build a 3D object with fine internal features. Modeling was used to develop prototype designs and predict the thermal response, stress, and efficiency in the ceramic heat exchangers. Build testing and materials analyses were used to provide feedback for the design selection. During this development process, laminated object manufacturing protocols were established. This included laser optimization, strategies for fine feature integrity, lamination fluid control, green handling, and firing profile. Three full size prototypes were fabricated using two different designs. One prototype was selected for performance testing. During testing, cross talk leakage prevented the application of a high pressure differential, however, the prototype was successful at withstanding the high temperature operating conditions (1300 °F). In addition, analysis showed that the bulk of the part did not have cracks or leakage issues. This led to the development of a module method for next generation LOM heat exchangers. A scale-up cost analysis showed that given a purpose built LOM system, these ceramic heat exchangers would be affordable for the applications.

  16. The effects of the coke addition and the heating time on the efficiency of chlorination process

    International Nuclear Information System (INIS)

    Masduki, B.; Indrati, Y. T.; Wahyuadi, J.; Triswanto, I. H.


    The preparation of mixed pellet, ZrO 2 , coke and sucrose, for chlorinating process of ZrO 2 pellet has been performed. In this experiments the studied parameters were coke addition and the heating time. The addition of coke was 9.72 grams, 10.5 grams and 11 for the mixture of the 87 grams ZrO 2 and 3.5 grams sucrose. The purpose of the coke addition is to from ZrC, which is corresponding to Kroll process with carbon-chlor methos. The weight of cokes had been calculated beyond the stoichiometry. The heating times was held in 10 minutes, 15 minutes, and 20 minutes at the temperature of 100 o C that was below the evaporation coke temperature of 315 o C. The result show that the efficiency of chlorinating of ZrO 2 pellet could be reached of 82.16% with the addition of coke mass of 11 grams at the heating temperature of 100 o C with the heating time of 20 minutes

  17. [Crusted scabies: A review]. (United States)

    Jouret, G; Bounemeur, R; Presle, A; Takin, R


    Crusted scabies is a rare and severe form of infestation by Sarcoptes scabies var. hominis. It is characterized by profuse hyperkeratosis containing over 4000 mites per gram of skin, with treatment being long and difficult. The condition is both direct and indirectly contagious. It has a central role in epidemic cycles of scabies, the incidence of which is on the rise in economically stable countries. Recent discoveries concerning the biology of mites, the pathophysiology of hyperkeratosis and the key role of IL-17 in this severe form open up new therapeutic perspectives. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Variation of muscle efficiency and regulation of heat production in an organism

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, K.P.


    The results of over twenty years of studies on the mechanism of heat production during muscle contraction in homiothermic organisms are presented. The mechanisms regulating energy exchange during contractile (or shivering) thermogenesis and noncontractile muscle thermogenesis are examined, with special consideration given to the efficiency coefficients (ECs) of muscle work related to the processes of muscle contraction and ATP synthesis, and to relative changes in these ECs. Special attention is given to the effect of acclimatization to cold on muscle energetics, when the EC of the muscle contraction falls, while the heat production increases; the mechanism of this phenomenon is considered to be related to the increasing degree of uncoupling between the oxidation and phosphorylation processes. The role of hormones and of the sympathetic nervous system in thermoregulation is discussed. 71 references.

  19. Magnetically-Driven Quantum Heat Engines: The Quasi-Static Limit of Their Efficiency

    Directory of Open Access Journals (Sweden)

    Enrique Muñoz


    Full Text Available The concept of a quantum heat engine (QHEN has been discussed in the literature, not only due to its intrinsic scientific interest, but also as an alternative to efficiently recover, on a nanoscale device, thermal energy in the form of useful work. The quantum character of a QHEN relies, for instance, on the fact that any of its intermediate states is determined by a density matrix operator. In particular, this matrix can represent a mixed state. For a classical heat engine, a theoretical upper bound for its efficiency is obtained by analyzing its quasi-static operation along a cycle drawn by a sequence of quasi-equilibrium states. A similar analysis can be carried out for a quantum engine, where quasi-static processes are driven by the evolution of ensemble-averaged observables, via variation of the corresponding operators or of the density matrix itself on a tunable physical parameter. We recently proposed two new conceptual designs for a magnetically-driven quantum engine, where the tunable parameter is the intensity of an external magnetic field. Along this article, we shall present the general quantum thermodynamics formalism developed in order to analyze this type of QHEN, and moreover, we shall apply it to describe the theoretical efficiency of two different practical implementations of this concept: an array of semiconductor quantum dots and an ensemble of graphene flakes submitted to mechanical tension.

  20. Heating efficiency of high-power perpendicular neutral-beam injection in PDX

    International Nuclear Information System (INIS)

    Hawryluk, R.J.; Arunasalam, V.; Bell, M.


    The heating efficiency of high power (up to 7.2 MW) near-perpendicular neutral beam injection in the PDX tokamak is comparable to that of tangential injection in PLT. Collisionless plasmas with central ion temperatures up to 6.5 keV and central electron temperatures greater than 2.5 keV have been obtained. The plasma pressure, including the contribution from the beam particles, increases with increasing beam power and does not appear to saturate, although the parametric dependence of the energy confinement time is different from that observed in ohmic discharges

  1. Description of innovative power technologies for biomass using. High efficiency combined production of heat, cold and electricity - ORC technologies

    International Nuclear Information System (INIS)

    Mileva, D.


    The ORC - technologies (Organic Rankine Cycle) are comfortable to be used for combined heat and power production for domestic and industrial needs (local supply), mean for their height efficiency and long exploitation period. Biomass is a primary energy source. (author)

  2. High-efficiency ventilation and heating systems by means of solar air collectors for industry building refurbishment


    Benoit Sicre; Patrick Baumann


    For the purpose of energy conservation, modern buildings are becoming more and more air-tight and generally rely on a mechanical ventilation system. According to the literature, solar air heating systems can contribute in a cost-effective way to the heating and ventilation of utility buildings. Especially cost-efficient, unglazed, façade-integrated solar air collectors seem to be an attractive new market for façade renovation. To demonstrate the technical feasibility of generating heating ene...

  3. Effects of dark energy on the efficiency of charged AdS black holes as heat engines (United States)

    Liu, Hang; Meng, Xin-He


    In this paper, we study the heat engine where a charged AdS black hole surrounded by dark energy is the working substance and the mechanical work is done via the PdV term in the first law of black hole thermodynamics in the extended phase space. We first investigate the effects of a kind of dark energy (quintessence field in this paper) on the efficiency of the RN-AdS black holes as the heat engine defined as a rectangular closed path in the P- V plane. We get the exact efficiency formula and find that the quintessence field can improve the heat engine efficiency, which will increase as the field density ρ _q grows. At some fixed parameters, we find that a larger volume difference between the smaller black holes(V_1) and the bigger black holes(V_2 ) will lead to a lower efficiency, while the bigger pressure difference P_1-P_4 will make the efficiency higher, but it is always smaller than 1 and will never be beyond the Carnot efficiency, which is the maximum value of the efficiency constrained by thermodynamics laws; this is consistent to the heat engine in traditional thermodynamics. After making some special choices for the thermodynamical quantities, we find that the increase of the electric charge Q and the normalization factor a can also promote the heat engine efficiency, which would infinitely approach the Carnot limit when Q or a goes to infinity.

  4. Purmerend wants to heat city of the Netherlands. Efficient distribution of sustainable heat; Purmerend wil warmtestad van Nederland worden. Efficiente distributie van duurzame warmte

    Energy Technology Data Exchange (ETDEWEB)

    Stollmeyer, A. [Stadsverwarming Purmerend, Purmerend (Netherlands)


    Stadsverwarming Purmerend (District heating) is working on realizing the most sustainable heating company in the Netherlands. This is to be realized by means of an energy transition: the transition from grey waste heat to green energy sources such as biomass and deep geothermal energy. Moreover, the SlimNet program is used to efficiently distribute heat generated from sustainable sources. The system will enter into operation in 2014. [Dutch] Stadsverwarming Purmerend werkt aan het duurzaamste warmtebedrijf van Nederland. Een en ander wordt gerealiseerd via een energietransitie: de overstap van grijze restwarmte naar groene energiebronnen als biomassa en diepe geothermie. Ook wordt het programma SlimNet ingezet om de duurzaam geproduceerde warmte efficient te distribueren. Het systeem wordt in 2014 operationeel.

  5. Designing a solar powered Stirling heat engine based on multiple criteria: Maximized thermal efficiency and power

    International Nuclear Information System (INIS)

    Ahmadi, Mohammad Hossein; Sayyaadi, Hoseyn; Dehghani, Saeed; Hosseinzade, Hadi


    Highlights: • Thermodynamic model of a solar-dish Stirling engine was presented. • Thermal efficiency and output power of the engine were simultaneously maximized. • A final optimal solution was selected using several decision-making methods. • An optimal solution with least deviation from the ideal design was obtained. • Optimal solutions showed high sensitivity against variation of system parameters. - Abstract: A solar-powered high temperature differential Stirling engine was considered for optimization using multiple criteria. A thermal model was developed so that the output power and thermal efficiency of the solar Stirling system with finite rate of heat transfer, regenerative heat loss, conductive thermal bridging loss, finite regeneration process time and imperfect performance of the dish collector could be obtained. The output power and overall thermal efficiency were considered for simultaneous maximization. Multi-objective evolutionary algorithms (MOEAs) based on the NSGA-II algorithm were employed while the solar absorber temperature and the highest and lowest temperatures of the working fluid were considered the decision variables. The Pareto optimal frontier was obtained and a final optimal solution was also selected using various decision-making methods including the fuzzy Bellman–Zadeh, LINMAP and TOPSIS. It was found that multi-objective optimization could yield results with a relatively low deviation from the ideal solution in comparison to the conventional single objective approach. Furthermore, it was shown that, if the weight of thermal efficiency as one of the objective functions is considered to be greater than weight of the power objective, lower absorber temperature and low temperature ratio should be considered in the design of the Stirling engine

  6. Efficiency grains in Danish District Heating. Is here anything to learn from benchmarking?

    Energy Technology Data Exchange (ETDEWEB)

    Munksgaard, J.; Pade, L.L. [Amternes og Kommunernes Forskningsinstitut, Copenhagen (Denmark); Fristrup, P. [Risoe National Lab., Systemanalyse Dept., Roskilde (Denmark)


    Facing a market structure of independent heating systems and cost-of-service regulation the regulator considers ways to create incentives for increasing efficiency in heat production. One way is to implement benchmark regulation. The aim of this paper is twofold: 1) To investigate the potential for increasing productivity in Danish district heating production and 2) to examine whether benchmarking has a role to play. Using DEA (Data Envelopment Analysis) our analyses show that by assuming variable returns to scale there exist a potential to reduce production costs by 5-27 % depending on the portfolie of inputs and outputs included in the model. Further, our analyses show that the ranking of produres are much dependent on the choice of model. The weakness of DEA, however, is that the choice of model can not be founded on solid theoretical ground. Therefore it is hard to decide on the appropriate model to be used. That points to the conclusion that great care has to be taken when implementing benchmarking as a regulatory mean. (au)

  7. High-Efficiency Small-Scale Combined Heat and Power Organic Binary Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Costante Mario Invernizzi


    Full Text Available Small-CHP (Combined Heat and Power systems are generally considered a valuable technological option to the conventional boilers, in a technology developed context. If small-CHP systems are associated with the use of renewable energies (biomass, for example they could play an important role in distributed generation even in developing countries or, in any case, where there are no extensive electricity networks. Traditionally the considered heat engines for micro- or mini-CHP are: the gas engine, the gas turbine (with internal combustion, the steam engine, engine working according to the Stirling and to the Rankine cycles, the last with organic fluids. In principle, also fuel cells could be used. In this paper, we focus on small size Rankine cycles (10–15 k W with organic working fluids. The assumed heat source is hot combustion gases at high temperature (900–950 ∘ C and we assume to use only single stages axial turbines. The need to work at high temperatures, limits the choice of the right organic working fluids. The calculation results show the limitation in the performances of simple cycles and suggest the opportunity to resort to complex (binary cycle configurations to achieve high net conversion efficiencies (15–16%.

  8. Development and Demonstration of a High Efficiency, Rapid Heating, Low NOx Alternative to Conventional Heating of Round Steel Shapes, Steel Substrate (Strip) and Coil Box Transfer Bars

    Energy Technology Data Exchange (ETDEWEB)

    Kurek, Harry; Wagner, John


    Direct Flame Impingement involves the use of an array of very high-velocity flame jets impinging on a work piece to rapidly heat the work piece. The predominant mode of heat transfer is convection. Because of the locally high rate of heat transfer at the surface of the work piece, the refractory walls and exhaust gases of a DFI furnace are significantly cooler than in conventional radiant heating furnaces, resulting in high thermal efficiency and low NOx emissions. A DFI furnace is composed of a successive arrangement of heating modules through or by which the work piece is conveyed, and can be configured for square, round, flat, and curved metal shapes (e.g., billets, tubes, flat bars, and coiled bars) in single- or multi-stranded applications.

  9. Application of porous medium for efficiency improvement of a concentrated solar air heating system (United States)

    Prasartkaew, Boonrit


    The objective of this study is to evaluate the thermal efficiency of a concentrated solar collector for a high temperature air heating system. The proposed system consists of a 25-m2 focused multi-flat-mirror solar heliostat equipped with a porous medium solar collector/receiver which was installed on the top of a 3-m tower, called ‘tower receiver’. To know how the system efficiency cloud be improved by using porous medium, the proposed system with and without porous medium were tested and the comparative study was performed. The experimental results reveal that, for the proposed system, application of porous medium is promising, the efficiency can be increased about 2 times compared to the conventional one. In addition, due to the porous medium used in this study was the waste material with very low cost. It can be summarized that the substantial efficiency improvement with very low investment cost of the proposed system seem to be a vital measures for addressing the energy issues.

  10. Measurement uncertainties when determining heat rate, isentropic efficiency and swallowing capacity

    Energy Technology Data Exchange (ETDEWEB)

    Snygg, U.


    The objective of the project was to determine the uncertainties when calculating heat rate, isentropic efficiencies and swallowing capacities of power plants. Normally when a power plant is constructed, the supplier also guarantee some performance values, e.g. heat rate. When the plant is built and running under normal conditions, an evaluation is done and the guarantee values are checked. Different measured parameters influence the calculated value differently, and therefore a sensitivity factor can be defined as the sensitivity of a calculated value when the measured value is changing. The product of this factor and the uncertainty of the measured parameter gives an error of the calculated value. For every measured parameter, the above given factor has to be determined and then the root square sum gives the overall uncertainty of the calculated parameter. To receive acceptable data during the evaluation of the plant, a test code is to be followed. The test code also gives guidelines how big the errors of the measurements are. In this study, ASME PTC6 and DIN 1943 were used. The results show that not only the test code was of vital importance, but also the distribution of the power output of the HP-IP turbines contra LP turbines. A higher inlet pressure of the LP turbine gives a smaller uncertainty of the isentropic efficiency. An increase from 6 to 13 bar will lower the uncertainty 1.5 times. 10 refs, 24 figs, 23 tabs, 5 appendixes

  11. Targeting energy justice: Exploring spatial, racial/ethnic and socioeconomic disparities in urban residential heating energy efficiency

    International Nuclear Information System (INIS)

    Reames, Tony Gerard


    Fuel poverty, the inability of households to afford adequate energy services, such as heating, is a major energy justice concern. Increasing residential energy efficiency is a strategic fuel poverty intervention. However, the absence of easily accessible household energy data impedes effective targeting of energy efficiency programs. This paper uses publicly available data, bottom-up modeling and small-area estimation techniques to predict the mean census block group residential heating energy use intensity (EUI), an energy efficiency proxy, in Kansas City, Missouri. Results mapped using geographic information systems (GIS) and statistical analysis, show disparities in the relationship between heating EUI and spatial, racial/ethnic, and socioeconomic block group characteristics. Block groups with lower median incomes, a greater percentage of households below poverty, a greater percentage of racial/ethnic minority headed-households, and a larger percentage of adults with less than a high school education were, on average, less energy efficient (higher EUIs). Results also imply that racial segregation, which continues to influence urban housing choices, exposes Black and Hispanic households to increased fuel poverty vulnerability. Lastly, the spatial concentration and demographics of vulnerable block groups suggest proactive, area- and community-based targeting of energy efficiency assistance programs may be more effective than existing self-referral approaches. - Highlights: • Develops statistical model to predict block group (BG) residential heating energy use intensity (EUI), an energy efficiency proxy. • Bivariate and multivariate analyses explore racial/ethnic and socioeconomic relationships with heating EUI. • BGs with more racial/ethnic minority households had higher heating EUI. • BGs with lower socioeconomics had higher heating EUI. • Mapping heating EUI can facilitate effective energy efficiency intervention targeting.

  12. Modern State and Efficient Analysis of Heat Recovery in Fuel Furnaces Using High Temperature Recuperators. Part 1.

    Directory of Open Access Journals (Sweden)

    B. S. Soroka


    Full Text Available A modern method for determination of fuel efficiency which is used in high-temperature plants (industrial furnaces has been considered in the paper. The paper estimates a heat recovery role of flue gases at the furnace outlet with the purpose to save  natural gas and replace it with alternative gas fuel. Efficient heat-utilizing installations for high-temperature plants have been presented in the paper, examples of heat recovery unit application in various technological schemes including processes of biomass gasification.

  13. Using microwave heating to improve the desorption efficiency of high molecular weight VOC from beaded activated carbon. (United States)

    Fayaz, Mohammadreza; Shariaty, Pooya; Atkinson, John D; Hashisho, Zaher; Phillips, John H; Anderson, James E; Nichols, Mark


    Incomplete regeneration of activated carbon loaded with organic compounds results in heel build-up that reduces the useful life of the adsorbent. In this study, microwave heating was tested as a regeneration method for beaded activated carbon (BAC) loaded with n-dodecane, a high molecular weight volatile organic compound. Energy consumption and desorption efficiency for microwave-heating regeneration were compared with conductive-heating regeneration. The minimum energy needed to completely regenerate the adsorbent (100% desorption efficiency) using microwave regeneration was 6% of that needed with conductive heating regeneration, owing to more rapid heating rates and lower heat loss. Analyses of adsorbent pore size distribution and surface chemistry confirmed that neither heating method altered the physical/chemical properties of the BAC. Additionally, gas chromatography (with flame ionization detector) confirmed that neither regeneration method detectably altered the adsorbate composition during desorption. By demonstrating improvements in energy consumption and desorption efficiency and showing stable adsorbate and adsorbent properties, this paper suggests that microwave heating is an attractive method for activated carbon regeneration particularly when high-affinity VOC adsorbates are present.

  14. On the mathematic simulation of the energy efficiency for heat exchangers with the systems of impingement plane-parallel jets

    Directory of Open Access Journals (Sweden)

    Haritonova Larisa


    Full Text Available The article gives the analytical generalization of the data on the energy efficiency for heat exchangers with the flat heat exchange surface to which systems of impact plane parallel jets are sent. Functional relations of specific power consumption (per unit of area, which were obtained for the first time using the techniques of the similarity law, for moving a heat carrier are shown with regard to design and operation factors. The regression equations representing a mathematical model of the process enable to carry out an analysis of various factors impact on the parameter to be determined. The obtained results can be used to optimize or to create the calculation techniques for new highly-efficient heat exchange devices with jet plane -parallel impingement systems and also to reduce power consumption for moving a heat carrier.

  15. The increase of efficiency of pine oil by heating and usage in the flotation of oxidized Amasra coal

    Energy Technology Data Exchange (ETDEWEB)

    Karsilayan, H.; Afsar, H.; Yilmaz, N.; Yanic, C. (Yildiz University, Istanbul (Turkey). Dept. of Chemistry)


    The effect of heating temperature and time on the efficiency of pine oil was examined in the flotation of oxidized Amasra coal in this work. Samples were taken from waste heap Amasra coal which were collected in 1973-1978 and stored in atmospheric conditions. The optimized impeller speed was 1000 rpm, aeration rate was 35 ml/s and solid content of the pulp was 20% in the flotation tests. Motorin was added to the pulp as a collector. The pine oil was heated to 50, 75, 100, 125, 150, 175, 200{degree}C and used as a frother. The flotation results indicated that 125{degree}C was a suitable temperature for heating. Increasing the heating time increased the efficiency of pine oil. The recovery of combustibles also increased depending on the increase in the amount of oil heated for 5 hours at 125{degree}C. 11 refs., 3 figs., 5 tabs.

  16. Heat stress and recovery of photosystem II efficiency in wheat (Triticum aestivum L.) cultivars acclimated to different growth temperatures

    DEFF Research Database (Denmark)

    Haque, Sabibul; Kjær, Katrine Heinsvig; Rosenqvist, Eva


    The effect of heat stress on photosystem II (PS II) efficiency and post-stress recovery was studied in four wheat cultivars using chlorophyll fluorescence. The main aim was to examine the cultivar differences in relation to inhibition and recovery of PSII functionality after heat stress...... at different growth stages. The secondary aim was to investigate whether a pre-acclimation of plants to elevated temperature during the growth period induces a better tolerance to heat stress than for plants grown in ambient temperature or not. The plants were grown in two growth temperature conditions (15 °C...... and 25 °C) and subjected to heat stress (40 °C) for two days at early tillering and three days at anthesis and early grain development stages. The plants were returned to their original growth conditions after heat stress and recovery was observed for three days. The maximum photochemical efficiency (Fv...

  17. Physics of Neutron Star Crusts

    Directory of Open Access Journals (Sweden)

    Chamel Nicolas


    Full Text Available The physics of neutron star crusts is vast, involving many different research fields, from nuclear and condensed matter physics to general relativity. This review summarizes the progress, which has been achieved over the last few years, in modeling neutron star crusts, both at the microscopic and macroscopic levels. The confrontation of these theoretical models with observations is also briefly discussed.

  18. Economic potentials of CHP connected to district heat systems in Germany. Implementation of the EU Efficiency Directive

    International Nuclear Information System (INIS)

    Eikmeier, Bernd


    The EU Efficiency Directive (2012/27/EU) is requiring all member states to carry out an evaluation of the potential for highly efficient CHP and the efficient use of district heating and cooling by December 2015. The German Federal Ministry of Economic Affairs and Energy appointed this task to the Fraunhofer Institute for Manufacturing and Advanced Materials, division for Energy Systems Analysis (formerly Bremer Energie Institut) in conjunction with other partners. The results for the sector district- and communal heating with CHP, sub-sectors private households, trade and services industry, are presented in this article.

  19. Incentive mechanism design for the residential building energy efficiency improvement of heating zones in North China

    International Nuclear Information System (INIS)

    Zhong, Y.; Cai, W.G.; Wu, Y.; Ren, H.


    Starting with analyzing the investigation results by Ministry of Housing and Urban-Rural Development of China in 2005, more than half of the 10,236 participants are willing to improve the residential building energy efficiency and accept an additional cost of less than 10% of the total cost, the authors illustrate that incenting actions are necessary to improve building energy efficiency and build a central government-local government-market model. As a result of the model analysis, to pursue good execution effects brought by the incentive policies, the executors are required to distinguish the differences of incentive objects' economic activities and strongly respect the incenting on the energy conservation performance. A case study on the incentive policies of existing residential building energy efficiency improvement in heating zones in North China is given as well. Finally, it is strongly recommended to give the first priority to performance-based incentives so that to reduce the lazy behaviors of the incented objects and ensure the targets to be achieved.

  20. Methodology for Measurement the Energy Efficiency Involving Solar Heating Systems Using Stochastic Modelling

    Directory of Open Access Journals (Sweden)

    Bruno G. Menita


    Full Text Available The purpose of the present study is to evaluate gains through measurement and verification methodology adapted from the International Performance Measurement and Verification Protocol, from case studies involving Energy Efficiency Projects in the Goias State, Brazil. This paper also presents the stochastic modelling for the generation of future scenarios of electricity saving resulted by these Energy Efficiency Projects. The model is developed by using the Geometric Brownian Motion Stochastic Process with Mean Reversion associated with the Monte Carlo simulation technique. Results show that the electricity saved from the replacement of electric showers by solar water heating systems in homes of low-income families has great potential to bring financial benefits to such families, and that the reduction in peak demand obtained from this Energy Efficiency Action is advantageous to the Brazilian electrical system. Results contemplate also the future scenarios of electricity saving and a sensitivity analysis in order to verify how values of some parameters influence on the results, once there is no historical data available for obtaining these values.

  1. Investigation of material efficient fin patterns for cost-effective operation of fin and tube heat exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph


    and tube heat exchanger. Computational fluid dynamic models of fin and tube heat exchanger with different fin patterns are developed to investigate the fin pattern behavior on heat transfer and pressure loss performance data. In addition, the numerical results are utilized to analyze the engineering design......Design management of a thermal energy system is a critical part of identifying basic designs that meet large scale user demand under certain operating characteristics. Fin and tube heat exchangers are among the most commonly used thermal energy systems which are generating considerable interest...... scale-up heat exchanger configurations with each fin pattern focusing on the application of chosen fin and tube heat exchanger in marine exhaust gas boiler. The analysis highlights the impact of material efficient fin patterns investigated and predicts that the polynomial and sinusoidal fin patterns...

  2. Gas turbine efficiency enhancement using waste heat powered absorption chillers in the oil and gas industry

    International Nuclear Information System (INIS)

    Popli, Sahil; Rodgers, Peter; Eveloy, Valerie


    In hot climates, the efficiency of energy-intensive industrial facilities utilizing gas turbines for power generation, such as oil refineries and natural gas processing plants (NGPPs), can be enhanced by reducing gas turbine compressor inlet air temperature. This is typically achieved using either evaporative media coolers or electrically-driven mechanical vapor-compression chillers. However, the performance of evaporative media coolers is constrained in high relative humidity (RH) conditions, such as encountered in the Middle East and tropical regions, and such coolers require demineralized water supply, while electrically-driven mechanical vapor-compression chillers consume a significant amount of electric power. In this study, the use of gas turbine exhaust gas waste-heat powered, single-effect water–lithium bromide (H 2 O–LiBr) absorption chillers is thermo-economically evaluated for gas turbine compressor inlet air cooling scheme, with particular applicability to Middle East NGPPs. The thermodynamic performance of the proposed scheme, integrated in a NGPP, is compared with that of conventional evaporative coolers and mechanical vapor-compression chillers, in terms of key operating parameters, and either demineralized water or electricity consumption, respectively. The results show that in extreme ambient conditions representative of summer in the Persian Gulf (i.e., 55 °C, 80% RH), three steam-fired, single-effect H 2 O–LiBr absorption chillers utilizing 17 MW of gas turbine exhaust heat, could provide 12.3 MW of cooling to cool compressor inlet air to 10 °C. In the same ambient conditions, evaporative coolers would only provide 2.3 MW cooling capacity, and necessitate consumption of approximately 0.8 kg/s of demineralized water to be vaporized. In addition, mechanical vapor-compression chillers would require an additional 2.7 MW of electric energy to provide the same amount of cooling as H 2 O–LiBr absorption chillers. The additional electricity

  3. Unidirectional radiative heat transfer with a spectrally selective planar absorber/emitter for high-efficiency solar thermophotovoltaic systems (United States)

    Kohiyama, Asaka; Shimizu, Makoto; Yugami, Hiroo


    A high-efficiency solar thermophotovoltaic (STPV) system has been demonstrated using spectrally selective planar absorber/emitter systems and a GaSb TPV cell. In this study, a novel approach for designing the STPV system based on the efficiency of unidirectional radiative heat transfer has been introduced. To achieve high extraction and photovoltaic conversion efficiencies, the spectrally selective absorber/emitter based on a coherent perfect absorber composed of a thin molybdenum layer sandwiched between hafnium layers was applied. The extraction efficiency was further investigated with respect to the absorber/emitter area ratio. The experimental efficiency of STPV reached 5.1% with the area ratio of 2.3.

  4. Energy Efficiency and Performance Limiting Effects in Thermo-Osmotic Energy Conversion from Low-Grade Heat. (United States)

    Straub, Anthony P; Elimelech, Menachem


    Low-grade heat energy from sources below 100 °C is available in massive quantities around the world, but cannot be converted to electricity effectively using existing technologies due to variability in the heat output and the small temperature difference between the source and environment. The recently developed thermo-osmotic energy conversion (TOEC) process has the potential to harvest energy from low-grade heat sources by using a temperature difference to create a pressurized liquid flux across a membrane, which can be converted to mechanical work via a turbine. In this study, we perform the first analysis of energy efficiency and the expected performance of the TOEC technology, focusing on systems utilizing hydrophobic porous vapor-gap membranes and water as a working fluid. We begin by developing a framework to analyze realistic mass and heat transport in the process, probing the impact of various membrane parameters and system operating conditions. Our analysis reveals that an optimized system can achieve heat-to-electricity energy conversion efficiencies up to 4.1% (34% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and an operating pressure of 5 MPa (50 bar). Lower energy efficiencies, however, will occur in systems operating with high power densities (>5 W/m 2 ) and with finite-sized heat exchangers. We identify that the most important membrane properties for achieving high performance are an asymmetric pore structure, high pressure resistance, a high porosity, and a thickness of 30 to 100 μm. We also quantify the benefits in performance from utilizing deaerated water streams, strong hydrodynamic mixing in the membrane module, and high heat exchanger efficiencies. Overall, our study demonstrates the promise of full-scale TOEC systems to extract energy from low-grade heat and identifies key factors for performance optimization moving forward.

  5. Organic thermoelectric materials: emerging green energy materials converting heat to electricity directly and efficiently. (United States)

    Zhang, Qian; Sun, Yimeng; Xu, Wei; Zhu, Daoben


    The abundance of solar thermal energy and the widespread demands for waste heat recovery make thermoelectric generators (TEGs) very attractive in harvesting low-cost energy resources. Meanwhile, thermoelectric refrigeration is promising for local cooling and niche applications. In this context there is currently a growing interest in developing organic thermoelectric materials which are flexible, cost-effective, eco-friendly and potentially energy-efficient. In particular, the past several years have witnessed remarkable progress in organic thermoelectric materials and devices. In this review, thermoelectric properties of conducting polymers and small molecules are summarized, with recent progresses in materials, measurements and devices highlighted. Prospects and suggestions for future research efforts are also presented. The organic thermoelectric materials are emerging candidates for green energy conversion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Increased efficiency of targeted mutagenesis by CRISPR/Cas9 in plants using heat stress. (United States)

    LeBlanc, Chantal; Zhang, Fei; Mendez, Josefina; Lozano, Yamile; Chatpar, Krishna; Irish, Vivian F; Jacob, Yannick


    The CRISPR/Cas9 system has greatly improved our ability to engineer targeted mutations in eukaryotic genomes. While CRISPR/Cas9 appears to work universally, the efficiency of targeted mutagenesis and the adverse generation of off-target mutations vary greatly between different organisms. In this study, we report that Arabidopsis plants subjected to heat stress at 37°C show much higher frequencies of CRISPR-induced mutations compared to plants grown continuously at the standard temperature (22°C). Using quantitative assays relying on green fluorescent protein (GFP) reporter genes, we found that targeted mutagenesis by CRISPR/Cas9 in Arabidopsis is increased by approximately 5-fold in somatic tissues and up to 100-fold in the germline upon heat treatment. This effect of temperature on the mutation rate is not limited to Arabidopsis, as we observed a similar increase in targeted mutations by CRISPR/Cas9 in Citrus plants exposed to heat stress at 37°C. In vitro assays demonstrate that Cas9 from Streptococcus pyogenes (SpCas9) is more active in creating double-stranded DNA breaks at 37°C than at 22°C, thus indicating a potential contributing mechanism for the in vivo effect of temperature on CRISPR/Cas9. This study reveals the importance of temperature in modulating SpCas9 activity in eukaryotes, and provides a simple method to increase on-target mutagenesis in plants using CRISPR/Cas9. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  7. Microgrids: An emerging paradigm for meeting building electricityand heat requirements efficiently and with appropriate energyquality

    Energy Technology Data Exchange (ETDEWEB)

    Marnay, Chris; Firestone, Ryan


    The first major paradigm shift in electricity generation,delivery, and control is emerging in the developed world, notably Europe,North America, and Japan. This shift will move electricity supply awayfrom the highly centralised universal service quality model with which weare familiar today towards a more dispersed system with heterogeneousqualities of service. One element of dispersed control is the clusteringof sources and sinks into semi-autonomous mu grids (microgrids).Research, development, demonstration, and deployment (RD3) of mu gridsare advancing rapidly on at least three continents, and significantdemonstrations are currently in progress. This paradigm shift will resultin more electricity generation close to end-uses, often involvingcombined heat and power application for building heating and cooling,increased local integration of renewables, and the possible provision ofheterogeneous qualities of electrical service to match the requirementsof various end-uses. In Europe, mu grid RD3 is entering its third majorround under the 7th European Commission Framework Programme; in the U.S.,one specific mu grid concept is undergoing rigorous laboratory testing,and in Japan, where the most activity exists, four major publiclysponsored and two privately sponsored demonstrations are in progress.This evolution poses new challenges to the way buildings are designed,built, and operated. Traditional building energy supply systems willbecome much more complex in at least three ways: 1. one cannot simplyassume gas arrives at the gas meter, electricity at its meter, and thetwo systems are virtually independent of one another; rather, energyconversion, heat recovery and use, and renewable energy harvesting mayall be taking place simultaneously within the building energy system; 2.the structure of energy flows in the building must accommodate multipleenergy processes in a manner that permits high overall efficiency; and 3.multiple qualities of electricity may be supplied to

  8. Profiling Space Heating Behavior in Chilean Social Housing: Towards Personalization of Energy Efficiency Measures

    Directory of Open Access Journals (Sweden)

    Victor Bunster


    Full Text Available Global increases in the demand for energy are imposing strong pressures over the environment while compromising the capacity of emerging economies to achieve sustainable development. In this context, implementation of effective strategies to reduce consumption in residential buildings has become a priority concern for policy makers as minor changes at the household scale can result in major energy savings. This study aims to contribute to ongoing research on energy consumer profiling by exploring the forecasting capabilities of discrete socio-economic factors that are accessible through social housing allocation systems. Accordingly, survey data gathered by the Chilean Ministry of Social Development was used identify key characteristics that may predict firewood usage for space heating purposes among potential beneficiaries of the Chilean social housing program. The analyzed data evidences strong correlations between general household characteristics and space heating behavior in certain climatic zones, suggesting that personalized delivery of energy efficiency measures can potentially increase the effectiveness of initiatives aimed towards the reduction of current patterns of consumption.

  9. Regulating district heating in Romania: Legislative challenges and energy efficiency barriers

    International Nuclear Information System (INIS)

    Poputoaia, Diana; Bouzarovski, Stefan


    Many states in Eastern and Central Europe (ECE) possess extensive district heating (DH) networks that were constructed during the days of communist rule in order to provide a universally accessible energy service that supported Soviet development policies. But the post-communist transition was marked by the exacerbation of the sector's numerous technical, economic, regulatory and environmental problems, accompanied by its abandonment in favour of alternative methods of domestic heating. Recent efforts to increase the use of DH in ECE as a result of environmental and energy security concerns have taken place in an absence of critical, context-sensitive research. The purpose of this paper is to explore the legal aspects of post-communist DH reforms in Romania, with the aim of identifying some of the governance challenges faced by state authorities in managing the sector. In broader terms, we seek to explore the extent to which the Romanian legislative framework is in a position to promote energy efficiency in DH. This has been achieved via an analysis of formal policy documents, government decrees, strategic documents and laws pertaining to this sector, as published and subsequently amended in the Official Gazette. The conclusions of the paper identify the key regulatory issues in the sector-especially with respect to the tariff setting process and the division of competences among different organisations in it-while suggesting a set of policy steps and general restructuring approaches that could help overcome the current situation.

  10. Estimation of the effective heating systems radius as a method of the reliability improving and energy efficiency (United States)

    Akhmetova, I. G.; Chichirova, N. D.


    When conducting an energy survey of heat supply enterprise operating several boilers located not far from each other, it is advisable to assess the degree of heat supply efficiency from individual boiler, the possibility of energy consumption reducing in the whole enterprise by switching consumers to a more efficient source, to close in effective boilers. It is necessary to consider the temporal dynamics of perspective load connection, conditions in the market changes. To solve this problem the radius calculation of the effective heat supply from the thermal energy source can be used. The disadvantage of existing methods is the high complexity, the need to collect large amounts of source data and conduct a significant amount of computational efforts. When conducting an energy survey of heat supply enterprise operating a large number of thermal energy sources, rapid assessment of the magnitude of the effective heating radius requires. Taking into account the specifics of conduct and objectives of the energy survey method of calculation of effective heating systems radius, to use while conducting the energy audit should be based on data available heat supply organization in open access, minimize efforts, but the result should be to match the results obtained by other methods. To determine the efficiency radius of Kazan heat supply system were determined share of cost for generation and transmission of thermal energy, capital investment to connect new consumers. The result were compared with the values obtained with the previously known methods. The suggested Express-method allows to determine the effective radius of the centralized heat supply from heat sources, in conducting energy audits with the effort minimum and the required accuracy.

  11. High-Silica Hadean Crust (United States)

    Boehnke, P.; Bell, E. A.; Stephan, T.; Trappitsch, R.; Keller, C. B.; Pardo, O. S.; Davis, A. M.; Harrison, M.; Pellin, M. J.


    Understanding Hadean (>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. For example, compilations of whole-rock elemental abundances suggest to some a dominantly mafic crust, while the geochemistry and inclusions in Hadean zircons suggest the existence of felsic crust and possibly even life. We address this question by analyzing the 87Sr/86Sr ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, using the Chicago Instrument for Laser Ionization (CHILI). Our results show that the protolith of the Nuvvuagittuq zircons had formed a reservoir with a high (>1) Rb/Sr ratio by 4.4 Ga. The Rb/Sr ratio of this reservoir is too high to be explained by only a mafic crust or a terrestrial "KREEP" layer. Indeed, high Rb/Sr ratios only occur in high SiO2 rocks, and our data suggests that the 4.4 Ga Nuvvuagittuq source was felsic rather than mafic. Specifically, our results suggest that the 4.4 Ga Nuvvuagittuq protolith was of rhyolitic compositions. This finding implies that the early crust had a broad range of igneous rocks, extending from mafic to highly silicic compositions.

  12. Energy-Efficient Supermarket Heating, Ventilation, and Air Conditioning in Humid Climates in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)


    Supermarkets are energy-intensive buildings that consume the greatest amount of electricity per square foot of building of any building type in the United States and represent 5% of total U.S. commercial building primary energy use (EIA 2005). Refrigeration and heating, ventilation, and air-conditioning (HVAC) systems are responsible for a large proportion of supermarkets’ total energy use. These two systems sometimes work together and sometimes compete, but the performance of one system always affects the performance of the other. To better understand these challenges and opportunities, the Commercial Buildings team at the National Renewable Energy Laboratory investigated several of the most promising strategies for providing energy-efficient HVAC for supermarkets and quantified the resulting energy use and costs using detailed simulations. This research effort was conducted on behalf of the U.S. Department of Energy (DOE) Commercial Building Partnerships (CBP) (Baechler et al. 2012; Parrish et al. 2013; Antonopoulos et al. 2014; Hirsch et al. 2014). The goal of CBP was to reduce energy use in the commercial building sector by creating, testing, and validating design concepts on the pathway to net zero energy commercial buildings. Several CBP partners owned or operated buildings containing supermarkets and were interested in optimizing the energy efficiency of supermarket HVAC systems in hot-humid climates. These partners included Walmart, Target, Whole Foods Market, SUPERVALU, and the Defense Commissary Agency.

  13. Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating (United States)

    Kazakov, Ye. O.; Ongena, J.; Wright, J. C.; Wukitch, S. J.; Lerche, E.; Mantsinen, M. J.; van Eester, D.; Craciunescu, T.; Kiptily, V. G.; Lin, Y.; Nocente, M.; Nabais, F.; Nave, M. F. F.; Baranov, Y.; Bielecki, J.; Bilato, R.; Bobkov, V.; Crombé, K.; Czarnecka, A.; Faustin, J. M.; Felton, R.; Fitzgerald, M.; Gallart, D.; Giacomelli, L.; Golfinopoulos, T.; Hubbard, A. E.; Jacquet, Ph.; Johnson, T.; Lennholm, M.; Loarer, T.; Porkolab, M.; Sharapov, S. E.; Valcarcel, D.; van Schoor, M.; Weisen, H.; Marmar, E. S.; Baek, S. G.; Barnard, H.; Bonoli, P.; Brunner, D.; Candy, J.; Canik, J.; Churchill, R. M.; Cziegler, I.; Dekow, G.; Delgado-Aparicio, L.; Diallo, A.; Edlund, E.; Ennever, P.; Faust, I.; Fiore, C.; Gao, Chi; Golfinopoulos, T.; Greenwald, M.; Hartwig, Z. S.; Holland, C.; Hubbard, A. E.; Hughes, J. W.; Hutchinson, I. H.; Irby, J.; Labombard, B.; Lin, Yijun; Lipschultz, B.; Loarte, A.; Mumgaard, R.; Parker, R. R.; Porkolab, M.; Reinke, M. L.; Rice, J. E.; Scott, S.; Shiraiwa, S.; Snyder, P.; Sorbom, B.; Terry, D.; Terry, J. L.; Theiler, C.; Vieira, R.; Walk, J. R.; Wallace, G. M.; White, A.; Whyte, D.; Wolfe, S. M.; Wright, G. M.; Wright, J.; Wukitch, S. J.; Xu, P.; Abduallev, S.; Abhangi, M.; Abreu, P.; Afzal, M.; Aggarwal, K. M.; Ahlgren, T.; Ahn, J. H.; Aho-Mantila, L.; Aiba, N.; Airila, M.; Albanese, R.; Aldred, V.; Alegre, D.; Alessi, E.; Aleynikov, P.; Alfier, A.; Alkseev, A.; Allinson, M.; Alper, B.; Alves, E.; Ambrosino, G.; Ambrosino, R.; Amicucci, L.; Amosov, V.; Sundén, E. Andersson; Angelone, M.; Anghel, M.; Angioni, C.; Appel, L.; Appelbee, C.; Arena, P.; Ariola, M.; Arnichand, H.; Arshad, S.; Ash, A.; Ashikawa, N.; Aslanyan, V.; Asunta, O.; Auriemma, F.; Austin, Y.; Avotina, L.; Axton, M. D.; Ayres, C.; Bacharis, M.; Baciero, A.; Baião, D.; Bailey, S.; Baker, A.; Balboa, I.; Balden, M.; Balshaw, N.; Bament, R.; Banks, J. W.; Baranov, Y. F.; Barnard, M. A.; Barnes, D.; Barnes, M.; Barnsley, R.; Wiechec, A. Baron; Orte, L. Barrera; Baruzzo, M.; Basiuk, V.; Bassan, M.; Bastow, R.; Batista, A.; Batistoni, P.; Baughan, R.; Bauvir, B.; Baylor, L.; Bazylev, B.; Beal, J.; Beaumont, P. S.; Beckers, M.; Beckett, B.; Becoulet, A.; Bekris, N.; Beldishevski, M.; Bell, K.; Belli, F.; Bellinger, M.; Belonohy, É.; Ayed, N. Ben; Benterman, N. A.; Bergsåker, H.; Bernardo, J.; Bernert, M.; Berry, M.; Bertalot, L.; Besliu, C.; Beurskens, M.; Bieg, B.; Bielecki, J.; Biewer, T.; Bigi, M.; Bílková, P.; Binda, F.; Bisoffi, A.; Bizarro, J. P. S.; Björkas, C.; Blackburn, J.; Blackman, K.; Blackman, T. R.; Blanchard, P.; Blatchford, P.; Bobkov, V.; Boboc, A.; Bodnár, G.; Bogar, O.; Bolshakova, I.; Bolzonella, T.; Bonanomi, N.; Bonelli, F.; Boom, J.; Booth, J.; Borba, D.; Borodin, D.; Borodkina, I.; Botrugno, A.; Bottereau, C.; Boulting, P.; Bourdelle, C.; Bowden, M.; Bower, C.; Bowman, C.; Boyce, T.; Boyd, C.; Boyer, H. J.; Bradshaw, J. M. A.; Braic, V.; Bravanec, R.; Breizman, B.; Bremond, S.; Brennan, P. D.; Breton, S.; Brett, A.; Brezinsek, S.; Bright, M. D. J.; Brix, M.; Broeckx, W.; Brombin, M.; Brosławski, A.; Brown, D. P. D.; Brown, M.; Bruno, E.; Bucalossi, J.; Buch, J.; Buchanan, J.; Buckley, M. A.; Budny, R.; Bufferand, H.; Bulman, M.; Bulmer, N.; Bunting, P.; Buratti, P.; Burckhart, A.; Buscarino, A.; Busse, A.; Butler, N. K.; Bykov, I.; Byrne, J.; Cahyna, P.; Calabrò, G.; Calvo, I.; Camenen, Y.; Camp, P.; Campling, D. C.; Cane, J.; Cannas, B.; Capel, A. J.; Card, P. J.; Cardinali, A.; Carman, P.; Carr, M.; Carralero, D.; Carraro, L.; Carvalho, B. B.; Carvalho, I.; Carvalho, P.; Casson, F. J.; Castaldo, C.; Catarino, N.; Caumont, J.; Causa, F.; Cavazzana, R.; Cave-Ayland, K.; Cavinato, M.; Cecconello, M.; Ceccuzzi, S.; Cecil, E.; Cenedese, A.; Cesario, R.; Challis, C. D.; Chandler, M.; Chandra, D.; Chang, C. S.; Chankin, A.; Chapman, I. T.; Chapman, S. C.; Chernyshova, M.; Chitarin, G.; Ciraolo, G.; Ciric, D.; Citrin, J.; Clairet, F.; Clark, E.; Clark, M.; Clarkson, R.; Clatworthy, D.; Clements, C.; Cleverly, M.; Coad, J. P.; Coates, P. A.; Cobalt, A.; Coccorese, V.; Cocilovo, V.; Coda, S.; Coelho, R.; Coenen, J. W.; Coffey, I.; Colas, L.; Collins, S.; Conka, D.; Conroy, S.; Conway, N.; Coombs, D.; Cooper, D.; Cooper, S. R.; Corradino, C.; Corre, Y.; Corrigan, G.; Cortes, S.; Coster, D.; Couchman, A. S.; Cox, M. P.; Craciunescu, T.; Cramp, S.; Craven, R.; Crisanti, F.; Croci, G.; Croft, D.; Crombé, K.; Crowe, R.; Cruz, N.; Cseh, G.; Cufar, A.; Cullen, A.; Curuia, M.; Czarnecka, A.; Dabirikhah, H.; Dalgliesh, P.; Dalley, S.; Dankowski, J.; Darrow, D.; Davies, O.; Davis, W.; Day, C.; Day, I. E.; de Bock, M.; de Castro, A.; de La Cal, E.; de La Luna, E.; Masi, G. De; de Pablos, J. L.; de Temmerman, G.; de Tommasi, G.; de Vries, P.; Deakin, K.; Deane, J.; Agostini, F. Degli; Dejarnac, R.; Delabie, E.; den Harder, N.; Dendy, R. O.; Denis, J.; Denner, P.; Devaux, S.; Devynck, P.; Maio, F. Di; Siena, A. Di; Troia, C. Di; Dinca, P.; D'Inca, R.; Ding, B.; Dittmar, T.; Doerk, H.; Doerner, R. P.; Donné, T.; Dorling, S. E.; Dormido-Canto, S.; Doswon, S.; Douai, D.; Doyle, P. T.; Drenik, A.; Drewelow, P.; Drews, P.; Duckworth, Ph.; Dumont, R.; Dumortier, P.; Dunai, D.; Dunne, M.; Ďuran, I.; Durodié, F.; Dutta, P.; Duval, B. P.; Dux, R.; Dylst, K.; Dzysiuk, N.; Edappala, P. V.; Edmond, J.; Edwards, A. M.; Edwards, J.; Eich, Th.; Ekedahl, A.; El-Jorf, R.; Elsmore, C. G.; Enachescu, M.; Ericsson, G.; Eriksson, F.; Eriksson, J.; Eriksson, L. G.; Esposito, B.; Esquembri, S.; Esser, H. G.; Esteve, D.; Evans, B.; Evans, G. E.; Evison, G.; Ewart, G. D.; Fagan, D.; Faitsch, M.; Falie, D.; Fanni, A.; Fasoli, A.; Faustin, J. M.; Fawlk, N.; Fazendeiro, L.; Fedorczak, N.; Felton, R. C.; Fenton, K.; Fernades, A.; Fernandes, H.; Ferreira, J.; Fessey, J. A.; Février, O.; Ficker, O.; Field, A.; Fietz, S.; Figueiredo, A.; Figueiredo, J.; Fil, A.; Finburg, P.; Firdaouss, M.; Fischer, U.; Fittill, L.; Fitzgerald, M.; Flammini, D.; Flanagan, J.; Fleming, C.; Flinders, K.; Fonnesu, N.; Fontdecaba, J. M.; Formisano, A.; Forsythe, L.; Fortuna, L.; Fortuna-Zalesna, E.; Fortune, M.; Foster, S.; Franke, T.; Franklin, T.; Frasca, M.; Frassinetti, L.; Freisinger, M.; Fresa, R.; Frigione, D.; Fuchs, V.; Fuller, D.; Futatani, S.; Fyvie, J.; Gál, K.; Galassi, D.; Gałązka, K.; Galdon-Quiroga, J.; Gallagher, J.; Gallart, D.; Galvão, R.; Gao, X.; Gao, Y.; Garcia, J.; Garcia-Carrasco, A.; García-Muñoz, M.; Gardarein, J.-L.; Garzotti, L.; Gaudio, P.; Gauthier, E.; Gear, D. F.; Gee, S. J.; Geiger, B.; Gelfusa, M.; Gerasimov, S.; Gervasini, G.; Gethins, M.; Ghani, Z.; Ghate, M.; Gherendi, M.; Giacalone, J. C.; Giacomelli, L.; Gibson, C. S.; Giegerich, T.; Gil, C.; Gil, L.; Gilligan, S.; Gin, D.; Giovannozzi, E.; Girardo, J. B.; Giroud, C.; Giruzzi, G.; Glöggler, S.; Godwin, J.; Goff, J.; Gohil, P.; Goloborod'Ko, V.; Gomes, R.; Gonçalves, B.; Goniche, M.; Goodliffe, M.; Goodyear, A.; Gorini, G.; Gosk, M.; Goulding, R.; Goussarov, A.; Gowland, R.; Graham, B.; Graham, M. E.; Graves, J. P.; Grazier, N.; Grazier, P.; Green, N. R.; Greuner, H.; Grierson, B.; Griph, F. S.; Grisolia, C.; Grist, D.; Groth, M.; Grove, R.; Grundy, C. N.; Grzonka, J.; Guard, D.; Guérard, C.; Guillemaut, C.; Guirlet, R.; Gurl, C.; Utoh, H. H.; Hackett, L. J.; Hacquin, S.; Hagar, A.; Hager, R.; Hakola, A.; Halitovs, M.; Hall, S. J.; Cook, S. P. Hallworth; Hamlyn-Harris, C.; Hammond, K.; Harrington, C.; Harrison, J.; Harting, D.; Hasenbeck, F.; Hatano, Y.; Hatch, D. R.; Haupt, T. D. V.; Hawes, J.; Hawkes, N. C.; Hawkins, J.; Hawkins, P.; Haydon, P. W.; Hayter, N.; Hazel, S.; Heesterman, P. J. L.; Heinola, K.; Hellesen, C.; Hellsten, T.; Helou, W.; Hemming, O. N.; Hender, T. C.; Henderson, M.; Henderson, S. S.; Henriques, R.; Hepple, D.; Hermon, G.; Hertout, P.; Hidalgo, C.; Highcock, E. G.; Hill, M.; Hillairet, J.; Hillesheim, J.; Hillis, D.; Hizanidis, K.; Hjalmarsson, A.; Hobirk, J.; Hodille, E.; Hogben, C. H. A.; Hogeweij, G. M. D.; Hollingsworth, A.; Hollis, S.; Homfray, D. A.; Horáček, J.; Hornung, G.; Horton, A. R.; Horton, L. D.; Horvath, L.; Hotchin, S. P.; Hough, M. R.; Howarth, P. J.; Hubbard, A.; Huber, A.; Huber, V.; Huddleston, T. M.; Hughes, M.; Huijsmans, G. T. A.; Hunter, C. L.; Huynh, P.; Hynes, A. M.; Iglesias, D.; Imazawa, N.; Imbeaux, F.; Imríšek, M.; Incelli, M.; Innocente, P.; Irishkin, M.; Ivanova-Stanik, I.; Jachmich, S.; Jacobsen, A. S.; Jacquet, P.; Jansons, J.; Jardin, A.; Järvinen, A.; Jaulmes, F.; Jednoróg, S.; Jenkins, I.; Jeong, C.; Jepu, I.; Joffrin, E.; Johnson, R.; Johnson, T.; Johnston, Jane; Joita, L.; Jones, G.; Jones, T. T. C.; Hoshino, K. K.; Kallenbach, A.; Kamiya, K.; Kaniewski, J.; Kantor, A.; Kappatou, A.; Karhunen, J.; Karkinsky, D.; Karnowska, I.; Kaufman, M.; Kaveney, G.; Kazakov, Y.; Kazantzidis, V.; Keeling, D. L.; Keenan, T.; Keep, J.; Kempenaars, M.; Kennedy, C.; Kenny, D.; Kent, J.; Kent, O. N.; Khilkevich, E.; Kim, H. T.; Kim, H. S.; Kinch, A.; King, C.; King, D.; King, R. F.; Kinna, D. J.; Kiptily, V.; Kirk, A.; Kirov, K.; Kirschner, A.; Kizane, G.; Klepper, C.; Klix, A.; Knight, P.; Knipe, S. J.; Knott, S.; Kobuchi, T.; Köchl, F.; Kocsis, G.; Kodeli, I.; Kogan, L.; Kogut, D.; Koivuranta, S.; Kominis, Y.; Köppen, M.; Kos, B.; Koskela, T.; Koslowski, H. R.; Koubiti, M.; Kovari, M.; Kowalska-Strzęciwilk, E.; Krasilnikov, A.; Krasilnikov, V.; Krawczyk, N.; Kresina, M.; Krieger, K.; Krivska, A.; Kruezi, U.; Książek, I.; Kukushkin, A.; Kundu, A.; Kurki-Suonio, T.; Kwak, S.; Kwiatkowski, R.; Kwon, O. J.; Laguardia, L.; Lahtinen, A.; Laing, A.; Lam, N.; Lambertz, H. T.; Lane, C.; Lang, P. T.; Lanthaler, S.; Lapins, J.; Lasa, A.; Last, J. R.; Łaszyńska, E.; Lawless, R.; Lawson, A.; Lawson, K. D.; Lazaros, A.; Lazzaro, E.; Leddy, J.; Lee, S.; Lefebvre, X.; Leggate, H. J.; Lehmann, J.; Lehnen, M.; Leichtle, D.; Leichuer, P.; Leipold, F.; Lengar, I.; Lennholm, M.; Lerche, E.; Lescinskis, A.; Lesnoj, S.; Letellier, E.; Leyland, M.; Leysen, W.; Li, L.; Liang, Y.; Likonen, J.; Linke, J.; Linsmeier, Ch.; Lipschultz, B.; Litaudon, X.; Liu, G.; Liu, Y.; Lo Schiavo, V. P.; Loarer, T.; Loarte, A.; Lobel, R. C.; Lomanowski, B.; Lomas, P. J.; Lönnroth, J.; López, J. M.; López-Razola, J.; Lorenzini, R.; Losada, U.; Lovell, J. J.; Loving, A. B.; Lowry, C.; Luce, T.; Lucock, R. M. A.; Lukin, A.; Luna, C.; Lungaroni, M.; Lungu, C. P.; Lungu, M.; Lunniss, A.; Lupelli, I.; Lyssoivan, A.; MacDonald, N.; Macheta, P.; Maczewa, K.; Magesh, B.; Maget, P.; Maggi, C.; Maier, H.; Mailloux, J.; Makkonen, T.; Makwana, R.; Malaquias, A.; Malizia, A.; Manas, P.; Manning, A.; Manso, M. E.; Mantica, P.; Mantsinen, M.; Manzanares, A.; Maquet, Ph.; Marandet, Y.; Marcenko, N.; Marchetto, C.; Marchuk, O.; Marinelli, M.; Marinucci, M.; Markovič, T.; Marocco, D.; Marot, L.; Marren, C. A.; Marshal, R.; Martin, A.; Martin, Y.; Martín de Aguilera, A.; Martínez, F. J.; Martín-Solís, J. R.; Martynova, Y.; Maruyama, S.; Masiello, A.; Maslov, M.; Matejcik, S.; Mattei, M.; Matthews, G. F.; Maviglia, F.; Mayer, M.; Mayoral, M. L.; May-Smith, T.; Mazon, D.; Mazzotta, C.; McAdams, R.; McCarthy, P. J.; McClements, K. G.; McCormack, O.; McCullen, P. A.; McDonald, D.; McIntosh, S.; McKean, R.; McKehon, J.; Meadows, R. C.; Meakins, A.; Medina, F.; Medland, M.; Medley, S.; Meigh, S.; Meigs, A. G.; Meisl, G.; Meitner, S.; Meneses, L.; Menmuir, S.; Mergia, K.; Merrigan, I. R.; Mertens, Ph.; Meshchaninov, S.; Messiaen, A.; Meyer, H.; Mianowski, S.; Michling, R.; Middleton-Gear, D.; Miettunen, J.; Militello, F.; Militello-Asp, E.; Miloshevsky, G.; Mink, F.; Minucci, S.; Miyoshi, Y.; Mlynář, J.; Molina, D.; Monakhov, I.; Moneti, M.; Mooney, R.; Moradi, S.; Mordijck, S.; Moreira, L.; Moreno, R.; Moro, F.; Morris, A. W.; Morris, J.; Moser, L.; Mosher, S.; Moulton, D.; Murari, A.; Muraro, A.; Murphy, S.; Asakura, N. N.; Na, Y. S.; Nabais, F.; Naish, R.; Nakano, T.; Nardon, E.; Naulin, V.; Nave, M. F. F.; Nedzelski, I.; Nemtsev, G.; Nespoli, F.; Neto, A.; Neu, R.; Neverov, V. S.; Newman, M.; Nicholls, K. J.; Nicolas, T.; Nielsen, A. H.; Nielsen, P.; Nilsson, E.; Nishijima, D.; Noble, C.; Nocente, M.; Nodwell, D.; Nordlund, K.; Nordman, H.; Nouailletas, R.; Nunes, I.; Oberkofler, M.; Odupitan, T.; Ogawa, M. T.; O'Gorman, T.; Okabayashi, M.; Olney, R.; Omolayo, O.; O'Mullane, M.; Ongena, J.; Orsitto, F.; Orszagh, J.; Oswuigwe, B. I.; Otin, R.; Owen, A.; Paccagnella, R.; Pace, N.; Pacella, D.; Packer, L. W.; Page, A.; Pajuste, E.; Palazzo, S.; Pamela, S.; Panja, S.; Papp, P.; Paprok, R.; Parail, V.; Park, M.; Diaz, F. Parra; Parsons, M.; Pasqualotto, R.; Patel, A.; Pathak, S.; Paton, D.; Patten, H.; Pau, A.; Pawelec, E.; Soldan, C. Paz; Peackoc, A.; Pearson, I. J.; Pehkonen, S.-P.; Peluso, E.; Penot, C.; Pereira, A.; Pereira, R.; Puglia, P. P. Pereira; von Thun, C. Perez; Peruzzo, S.; Peschanyi, S.; Peterka, M.; Petersson, P.; Petravich, G.; Petre, A.; Petrella, N.; Petržilka, V.; Peysson, Y.; Pfefferlé, D.; Philipps, V.; Pillon, M.; Pintsuk, G.; Piovesan, P.; Dos Reis, A. Pires; Piron, L.; Pironti, A.; Pisano; Pitts, R.; Pizzo, F.; Plyusnin, V.; Pomaro, N.; Pompilian, O. G.; Pool, P. J.; Popovichev, S.; Porfiri, M. T.; Porosnicu, C.; Porton, M.; Possnert, G.; Potzel, S.; Powell, T.; Pozzi, J.; Prajapati, V.; Prakash, R.; Prestopino, G.; Price, D.; Price, M.; Price, R.; Prior, P.; Proudfoot, R.; Pucella, G.; Puglia, P.; Puiatti, M. E.; Pulley, D.; Purahoo, K.; Pütterich, Th.; Rachlew, E.; Rack, M.; Ragona, R.; Rainford, M. S. J.; Rakha, A.; Ramogida, G.; Ranjan, S.; Rapson, C. J.; Rasmussen, J. J.; Rathod, K.; Rattá, G.; Ratynskaia, S.; Ravera, G.; Rayner, C.; Rebai, M.; Reece, D.; Reed, A.; Réfy, D.; Regan, B.; Regaña, J.; Reich, M.; Reid, N.; Reimold, F.; Reinhart, M.; Reinke, M.; Reiser, D.; Rendell, D.; Reux, C.; Cortes, S. D. A. Reyes; Reynolds, S.; Riccardo, V.; Richardson, N.; Riddle, K.; Rigamonti, D.; Rimini, F. G.; Risner, J.; Riva, M.; Roach, C.; Robins, R. J.; Robinson, S. A.; Robinson, T.; Robson, D. W.; Roccella, R.; Rodionov, R.; Rodrigues, P.; Rodriguez, J.; Rohde, V.; Romanelli, F.; Romanelli, M.; Romanelli, S.; Romazanov, J.; Rowe, S.; Rubel, M.; Rubinacci, G.; Rubino, G.; Ruchko, L.; Ruiz, M.; Ruset, C.; Rzadkiewicz, J.; Saarelma, S.; Sabot, R.; Safi, E.; Sagar, P.; Saibene, G.; Saint-Laurent, F.; Salewski, M.; Salmi, A.; Salmon, R.; Salzedas, F.; Samaddar, D.; Samm, U.; Sandiford, D.; Santa, P.; Santala, M. I. K.; Santos, B.; Santucci, A.; Sartori, F.; Sartori, R.; Sauter, O.; Scannell, R.; Schlummer, T.; Schmid, K.; Schmidt, V.; Schmuck, S.; Schneider, M.; Schöpf, K.; Schwörer, D.; Scott, S. D.; Sergienko, G.; Sertoli, M.; Shabbir, A.; Sharapov, S. E.; Shaw, A.; Shaw, R.; Sheikh, H.; Shepherd, A.; Shevelev, A.; Shumack, A.; Sias, G.; Sibbald, M.; Sieglin, B.; Silburn, S.; Silva, A.; Silva, C.; Simmons, P. A.; Simpson, J.; Simpson-Hutchinson, J.; Sinha, A.; Sipilä, S. K.; Sips, A. C. C.; Sirén, P.; Sirinelli, A.; Sjöstrand, H.; Skiba, M.; Skilton, R.; Slabkowska, K.; Slade, B.; Smith, N.; Smith, P. G.; Smith, R.; Smith, T. J.; Smithies, M.; Snoj, L.; Soare, S.; Solano, E. R.; Somers, A.; Sommariva, C.; Sonato, P.; Sopplesa, A.; Sousa, J.; Sozzi, C.; Spagnolo, S.; Spelzini, T.; Spineanu, F.; Stables, G.; Stamatelatos, I.; Stamp, M. F.; Staniec, P.; Stankūnas, G.; Stan-Sion, C.; Stead, M. J.; Stefanikova, E.; Stepanov, I.; Stephen, A. V.; Stephen, M.; Stevens, A.; Stevens, B. D.; Strachan, J.; Strand, P.; Strauss, H. R.; Ström, P.; Stubbs, G.; Studholme, W.; Subba, F.; Summers, H. P.; Svensson, J.; Świderski, Ł.; Szabolics, T.; Szawlowski, M.; Szepesi, G.; Suzuki, T. T.; Tál, B.; Tala, T.; Talbot, A. R.; Talebzadeh, S.; Taliercio, C.; Tamain, P.; Tame, C.; Tang, W.; Tardocchi, M.; Taroni, L.; Taylor, D.; Taylor, K. A.; Tegnered, D.; Telesca, G.; Teplova, N.; Terranova, D.; Testa, D.; Tholerus, E.; Thomas, J.; Thomas, J. D.; Thomas, P.; Thompson, A.; Thompson, C.-A.; Thompson, V. K.; Thorne, L.; Thornton, A.; Thrysøe, A. S.; Tigwell, P. A.; Tipton, N.; Tiseanu, I.; Tojo, H.; Tokitani, M.; Tolias, P.; Tomeš, M.; Tonner, P.; Towndrow, M.; Trimble, P.; Tripsky, M.; Tsalas, M.; Tsavalas, P.; Jun, D. Tskhakaya; Turner, I.; Turner, M. M.; Turnyanskiy, M.; Tvalashvili, G.; Tyrrell, S. G. J.; Uccello, A.; Ul-Abidin, Z.; Uljanovs, J.; Ulyatt, D.; Urano, H.; Uytdenhouwen, I.; Vadgama, A. P.; Valcarcel, D.; Valentinuzzi, M.; Valisa, M.; Olivares, P. Vallejos; Valovic, M.; van de Mortel, M.; van Eester, D.; van Renterghem, W.; van Rooij, G. J.; Varje, J.; Varoutis, S.; Vartanian, S.; Vasava, K.; Vasilopoulou, T.; Vega, J.; Verdoolaege, G.; Verhoeven, R.; Verona, C.; Rinati, G. Verona; Veshchev, E.; Vianello, N.; Vicente, J.; Viezzer, E.; Villari, S.; Villone, F.; Vincenzi, P.; Vinyar, I.; Viola, B.; Vitins, A.; Vizvary, Z.; Vlad, M.; Voitsekhovitch, I.; Vondráček, P.; Vora, N.; Vu, T.; de Sa, W. W. Pires; Wakeling, B.; Waldon, C. W. F.; Walkden, N.; Walker, M.; Walker, R.; Walsh, M.; Wang, E.; Wang, N.; Warder, S.; Warren, R. J.; Waterhouse, J.; Watkins, N. W.; Watts, C.; Wauters, T.; Weckmann, A.; Weiland, J.; Weisen, H.; Weiszflog, M.; Wellstood, C.; West, A. T.; Wheatley, M. R.; Whetham, S.; Whitehead, A. M.; Whitehead, B. D.; Widdowson, A. M.; Wiesen, S.; Wilkinson, J.; Williams, J.; Williams, M.; Wilson, A. R.; Wilson, D. J.; Wilson, H. R.; Wilson, J.; Wischmeier, M.; Withenshaw, G.; Withycombe, A.; Witts, D. M.; Wood, D.; Wood, R.; Woodley, C.; Wray, S.; Wright, J.; Wright, J. C.; Wu, J.; Wukitch, S.; Wynn, A.; Xu, T.; Yadikin, D.; Yanling, W.; Yao, L.; Yavorskij, V.; Yoo, M. G.; Young, C.; Young, D.; Young, I. D.; Young, R.; Zacks, J.; Zagorski, R.; Zaitsev, F. S.; Zanino, R.; Zarins, A.; Zastrow, K. D.; Zerbini, M.; Zhang, W.; Zhou, Y.; Zilli, E.; Zoita, V.; Zoletnik, S.; Zychor, I.


    We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed `three-ion' scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3He ions to high energies in dedicated hydrogen-deuterium mixtures. Simultaneously, effective plasma heating is observed, as a result of the slowing-down of the fast 3He ions. The developed technique is not only limited to laboratory plasmas, but can also be applied to explain observations of energetic ions in space-plasma environments, in particular, 3He-rich solar flares.

  14. Investigation of Battery Heat Generation and Key Performance Indicator Efficiency Using Isothermal Calorimeter

    DEFF Research Database (Denmark)

    Khan, Mohammad Rezwan; Kær, Søren Knudsen


    , and the heat flux of the battery cell at the same time. Temperatures on the surface of the cell are measured using contact thermocouples, whereas, the heat flux is measured simultaneously by the isothermal calorimeter. This heat flux measurement is used for determining the heat generation inside the cell...

  15. Improving the Efficiency of the Heat Pump Control System of Carbon Dioxide Heat Pump with Several Evaporators and Gas Coolers

    Directory of Open Access Journals (Sweden)

    Sit M.L.


    Full Text Available The problem of coordination of the values of the refrigerant flow through the evaporators and gas coolers of the heat pump for the simultaneous production of heat and cold is studied. The compensation of the variations of the total flow through the evaporators is implemented using the variation of the capacity of the compressor and a corresponding change in flow through the auxiliary gas cooler of the heat pump. Control system of this gas cooler is constructed using the invariance principle of the output value (outlet temperature of the heated agent with respect to perturbations on the control channel (the refrigerant flow through the gas cooler. Principle of dual-channel compensation of the disturbance and advancing signal on input of control valve of the refrigerant through the gas cooler is ensured. Due to proposed solution, the intensity of the disturbances on the flow of refrigerant is reduced. Due to proposed technical solution power consumed by the heat pump compressor drive under transients is decreased.

  16. Modern State and Efficiency Analysis of Heat Recovery in Fuel Furnaces Using High Temperature Recuperators. Part 2

    Directory of Open Access Journals (Sweden)

    B. S. Soroka


    Full Text Available The paper analyzes various factors that affect upon heat transfer in high temperature recuperators, namely: heat transfer enhancement, heat exchange surface increase and rise of temperature head between primary and secondary heat transfer fluids. Comparison of experimental data with the results of mathematical and computational fluid dynamics (CFD modeling has been performed in the paper. The paper considers some new designs of high temperature heat recovery plants: tube recuperator equipped with internal inserts – secondary emitters inside tubes for metallurgical furnaces and high-efficient two-way radiative recuperators for machinery engineering furnaces.  Advantages of new recuperators in comparison with existing analogues have been estimated in the paper. These advantages are:  provision of additional fuel saving due to increase of preheating temperature of the combustion air and improvement of design stability by decrease of tube wall temperature.

  17. The Effect of Nanoparticles on Thermal Efficiency of Double Tube Heat Exchangers in Turbulent Flow


    Aghayari, Reza; Madah, Heydar; Keyvani, Bahram; Moghadassi, Abdolreza; Ashori, Fatemeh


    This paper refers to the Overall Heat Transfer Coefficient of Nano Fluids (OHTCNF) in heat exchangers and the relevant effective parameters. An improvement in Heat Transfer (HT) and OHTCNF containing nanoaluminum oxide with ca. 20 nm particle size and particular volume fraction in the range of 0.001-0.002 has been reported. The effects of temperature and concentration of nanoparticles on HT variation as well as Overall Heat Transfer Coefficient (OHTC) in a countercurrent double tube heat exch...

  18. Energy efficiency policies for space heating in EU countries: A panel data analysis for the period 1990–2010

    International Nuclear Information System (INIS)

    Ó Broin, Eoin; Nässén, Jonas; Johnsson, Filip


    Highlights: • Space heating demand between 1990 and 2010 modelled using a panel of 14 EU countries. • The impacts of 260 efficiency polices affecting space heating demand are examined. • Regulatory policies found to have had a greater success than financial or informative. • High priority should be given to regulatory policies for space heating energy goals. - Abstract: We present an empirical analysis of the more than 250 space heating-focused energy efficiency policies that have been in force at the EU and national levels in the period 1990–2010. This analysis looks at the EU-14 residential sector (Pre-2004 EU-15, excluding Luxembourg) using a panel data regression analysis on unit consumption of energy for space heating (kWh/m 2 /year). The policies are represented as a regression variable using a semi-quantitative impact estimation obtained from the MURE Policy Database. The impacts of the policies as a whole, and subdivided into financial, regulatory, and informative policies, are examined. The correlation between the actual reductions in demand and the estimated impact of regulatory policies is found to be stronger than the corresponding correlations with the respective impacts of financial policies and informative polices. Together with the well-known market barriers to energy efficiency that exist in the residential sector, these findings suggest that regulatory policy measures be given a high priority in the design of an effective pathway towards the EU-wide goals for space heating energy

  19. Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine (United States)

    Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.


    A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

  20. Radiative heat transfer enhancement using geometric and spectral control for achieving high-efficiency solar-thermophotovoltaic systems (United States)

    Kohiyama, Asaka; Shimizu, Makoto; Yugami, Hiroo


    We numerically investigate radiative heat transfer enhancement using spectral and geometric control of the absorber/emitter. A high extraction of the radiative heat transfer from the emitter as well as minimization of the optical losses from the absorber leads to high extraction and solar thermophotovoltaic (STPV) system efficiency. The important points for high-efficiency STPV design are discussed for the low and high area ratio of the absorber/emitter. The obtained general guideline will support the design of various types of STPV systems.

  1. Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate (United States)

    Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min


    Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.

  2. Heat strain and gross efficiency during endurance exercise after lower, upper, or whole body precooling in the heat

    NARCIS (Netherlands)

    Daanen, H. A.; van Es, E.M.; De Graaf, J. L.

    The maximal power that muscles can generate is reduced at low muscle temperatures. However, in prolonged heavy exercise in the heat, a high core temperature may be the factor limiting performance. Precooling has been shown to delay the attainment of hyperthermia. It is still unclear if the whole

  3. Heat Shock Protein 90 Ensures Efficient Mumps Virus Replication by Assisting with Viral Polymerase Complex Formation. (United States)

    Katoh, Hiroshi; Kubota, Toru; Nakatsu, Yuichiro; Tahara, Maino; Kidokoro, Minoru; Takeda, Makoto


    Paramyxoviral RNAs are synthesized by a viral RNA-dependent RNA polymerase (RdRp) consisting of the large (L) protein and its cofactor phosphoprotein (P protein). The L protein is a multifunctional protein that catalyzes RNA synthesis, mRNA capping, and mRNA polyadenylation. Growing evidence shows that the stability of several paramyxovirus L proteins is regulated by heat shock protein 90 (Hsp90). In this study, we demonstrated that Hsp90 activity was important for mumps virus (MuV) replication. The Hsp90 activity was required for L-protein stability and activity because an Hsp90-specific inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), destabilized the MuV L protein and suppressed viral RNA synthesis. However, once the L protein formed a mature polymerase complex with the P protein, Hsp90 activity was no longer required for the stability and activity of the L protein. When the Hsp90 activity was inhibited, the MuV L protein was degraded through the CHIP (C terminus of Hsp70-interacting protein)-mediated proteasomal pathway. High concentrations of 17-AAG showed strong cytotoxicity to certain cell types, but combined use of an Hsp70 inhibitor, VER155008, potentiated degradation of the L protein, allowing a sufficient reduction of 17-AAG concentration to block MuV replication with minimum cytotoxicity. Regulation of the L protein by Hsp90 and Hsp70 chaperones was also demonstrated for another paramyxovirus, the measles virus. Collectively, our data show that the Hsp90/Hsp70 chaperone machinery assists in the maturation of the paramyxovirus L protein and thereby in the formation of a mature RdRp complex and efficient viral replication. IMPORTANCE Heat shock protein 90 (Hsp90) is nearly universally required for viral protein homeostasis. Here, we report that Hsp90 activity is required for efficient propagation of mumps virus (MuV). Hsp90 functions in the maintenance of the catalytic subunit of viral polymerase, the large (L) protein, prior to formation of a

  4. Influence of oblique angle and heating height on flame structure, temperature field and efficiency of an impinging laminar jet flame

    Energy Technology Data Exchange (ETDEWEB)

    Shuhn Shyurng Hou [Kun Shan Univ. of Technology, Yung Kung City, Tainan, Taiwan (China). Dept. of Mechanical Engineering; Yung Chang Ko [National Cheng Kung Univ., Tainan, Taiwan (China). Dept. of Mechanical Engineering


    An experimental study is performed to determine the combined effects of oblique angle ({theta}) and heating height (H) on the flame structure, temperature field and thermal efficiency of a laminar premixed methane-air flame impinging on a plane surface. A double-flame burning of a Bunsen flame under a fuel-rich condition is used. It is found that the flame structure, temperature distribution and thermal efficiency depend strongly on the oblique angle and heating height. The influence of the oblique angle on flame structure is stronger for lower heating heights but is relatively weak for higher heating heights. For normal impingement, axisymmetric temperature distributions are found, which is attributed to the axisymmetric flame structure. However, a jet flame impinging at an angle onto the horizontal plate creates an asymmetric flame structure and, thus, results in asymmetric temperature distributions. The results show that as the oblique angle is reduced from 90{sup o} to 60{sup o}, the high-temperature zone shifts toward the major flow region. An optimum operating condition of the burner, identified by the widest high-temperature zone and the highest thermal efficiency, is achieved under the condition of {theta} = 60{sup o} and H = 12 mm. In general, a decrease of the oblique angle leads to a decrease in thermal efficiency. However, for the cases of lower heating heights (i.e. H {<=} 12 mm), the trend may be reversed. Furthermore, for a fixed oblique angle, as the heating height is increased, the thermal efficiency first increases to a maximum value and then decreases. (author)

  5. Development of a Wind Directly Forced Heat Pump and Its Efficiency Analysis


    Ching-Song Jwo; Zi-Jie Chien; Yen-Lin Chen; Chao-Chun Chien


    The requirements of providing electric energy through the wind-forced generator to the heat pump for water cooling and hot water heating grow significantly by now. This study proposes a new technique to directly adopt the wind force to drive heat pump systems, which can effectively reduce the energy conversion losses during the processes of wind force energy converting to electric energy and electric energy converting to kinetic energy. The operation of heat pump system transfers between chil...


    Directory of Open Access Journals (Sweden)

    Khavanov Pavel Aleksandrovich


    the heating system analysis and to define the area of application of various systems of heat supply. The principal decision based on the basis of the above analysis is the decision to install an independent or a centralized system of heat supply.

  7. Comparative analysis of the efficiency of air source heat pumps in different climatic areas of Iran

    NARCIS (Netherlands)

    Tabatabaei, S.; Treur, J.; Sotoca, Adolf; Catalani, Ana; Ghoneem, Mahmoud Y.; Amer, Mourad S.


    To address the problems caused by fossil energy usage it is important to make a transition to renewable sources of energy, in particular in the residential area. Heating systems such as air source heat pumps that gather heat energy from the ambient air are useful alternatives. However, whether or

  8. Energy efficiency of acetone, butanol, and ethanol (ABE) recovery by heat-integrated distillation. (United States)

    Grisales Diaz, Victor Hugo; Olivar Tost, Gerard


    Acetone, butanol, and ethanol (ABE) is an alternative biofuel. However, the energy requirement of ABE recovery by distillation is considered elevated (> 15.2 MJ fuel/Kg-ABE), due to the low concentration of ABE from fermentation broths (between 15 and 30 g/l). In this work, to reduce the energy requirements of ABE recovery, four processes of heat-integrated distillation were proposed. The energy requirements and economic evaluations were performed using the fermentation broths of several biocatalysts. Energy requirements of the processes with four distillation columns and three distillation columns were similar (between 7.7 and 11.7 MJ fuel/kg-ABE). Double-effect system (DED) with four columns was the most economical process (0.12-0.16 $/kg-ABE). ABE recovery from dilute solutions by DED achieved energy requirements between 6.1 and 8.7 MJ fuel/kg-ABE. Vapor compression distillation (VCD) reached the lowest energy consumptions (between 4.7 and 7.3 MJ fuel/kg-ABE). Energy requirements for ABE recovery DED and VCD were lower than that for integrated reactors. The energy requirements of ABE production were between 1.3- and 2.0-fold higher than that for alternative biofuels (ethanol or isobutanol). However, the energy efficiency of ABE production was equivalent than that for ethanol and isobutanol (between 0.71 and 0.76) because of hydrogen production in ABE fermentation.

  9. Design of energy-efficient buildings using interaction between Building Simulation Programme and Energy Supply Simulations for District Heating

    DEFF Research Database (Denmark)

    Christensen, Jørgen Erik; Dalla Rosa, Alessandro; Nagla, Inese

    potential of the energy saving in the society it is very important to address the decisive involvement of the end-users. The human behaviour is the factor that affects the most the energy use in low-energy buildings and should be included in energy simulations. The results can then be linked to programs...... simulating the energy supply system in order to support the design of CO2-free communities. The cases considered, although referring to the Danish tradition in the construction sector and to the Danish climate, have a general value and are adaptable to other situations and countries. The results demonstrate...... that there is a large potential for distributing energy in areas with energy efficient buildings. As a measure for the feasibility of district heating, the linear heat density can be used as a representative value, and the results show that it is possible to supply heat with low-energy district heating networks...

  10. Improving the Cooling Efficiency of Heat Sinks through the Use of Different Types of Phase Change Materials

    Directory of Open Access Journals (Sweden)

    Ibrahim Mjallal


    Full Text Available As the temperature of electronic devices increases, their failure rate increases. That is why electrical devices should be cooled. One of the promising cooling techniques is using Phase Change Materials (PCMs. A new passive temperature management technique, that involves the direct placement of PCMs on the chip, has been explored and developed. PCMs are potential temperature regulators that can store thermal energy and release it during melting and freezing respectively. PCM-based heat sinks can efficiently store the heat dissipated from the electronic components to delay the peak temperature of the electronic devices as much as possible and then release the stored energy during the off period. This paper compares the temperature distribution on a heat sink with and without PCM with different magnitudes of heat flux. Also, two different PCMs with different densities, namely salt-hydrate and wax, have been investigated in cooling electronic devices.

  11. Thermo-mechanical efficiency of the bimetallic strip heat engine at the macro-scale and micro-scale

    International Nuclear Information System (INIS)

    Arnaud, A; Boughaleb, J; Monfray, S; Boeuf, F; Skotnicki, T; Cugat, O


    Bimetallic strip heat engines are energy harvesters that exploit the thermo-mechanical properties of bistable bimetallic membranes to convert heat into mechanical energy. They thus represent a solution to transform low-grade heat into electrical energy if the bimetallic membrane is coupled with an electro-mechanical transducer. The simplicity of these devices allows us to consider their miniaturization using MEMS fabrication techniques. In order to design and optimize these devices at the macro-scale and micro-scale, this article proposes an explanation of the origin of the thermal snap-through by giving the expressions of the constitutive equations of composite beams. This allows us to evaluate the capability of bimetallic strips to convert heat into mechanical energy whatever their size is, and to give the theoretical thermo-mechanical efficiencies which can be obtained with these harvesters. (paper)

  12. Heat

    CERN Document Server

    Lawrence, Ellen


    Is it possible to make heat by rubbing your hands together? Why does an ice cube melt when you hold it? In this title, students will conduct experiments to help them understand what heat is. Kids will also investigate concepts such as which materials are good at conducting heat and which are the best insulators. Using everyday items that can easily be found around the house, students will transform into scientists as they carry out step-by-step experiments to answer interesting questions. Along the way, children will pick up important scientific skills. Heat includes seven experiments with detailed, age-appropriate instructions, surprising facts and background information, a "conclusions" section to pull all the concepts in the book together, and a glossary of science words. Colorful, dynamic designs and images truly put the FUN into FUN-damental Experiments.

  13. An efficient method based on the uniformity principle for synthesis of large-scale heat exchanger networks

    International Nuclear Information System (INIS)

    Zhang, Chunwei; Cui, Guomin; Chen, Shang


    Highlights: • Two dimensionless uniformity factors are presented to heat exchange network. • The grouping of process streams reduces the computational complexity of large-scale HENS problems. • The optimal sub-network can be obtained by Powell particle swarm optimization algorithm. • The method is illustrated by a case study involving 39 process streams, with a better solution. - Abstract: The optimal design of large-scale heat exchanger networks is a difficult task due to the inherent non-linear characteristics and the combinatorial nature of heat exchangers. To solve large-scale heat exchanger network synthesis (HENS) problems, two dimensionless uniformity factors to describe the heat exchanger network (HEN) uniformity in terms of the temperature difference and the accuracy of process stream grouping are deduced. Additionally, a novel algorithm that combines deterministic and stochastic optimizations to obtain an optimal sub-network with a suitable heat load for a given group of streams is proposed, and is named the Powell particle swarm optimization (PPSO). As a result, the synthesis of large-scale heat exchanger networks is divided into two corresponding sub-parts, namely, the grouping of process streams and the optimization of sub-networks. This approach reduces the computational complexity and increases the efficiency of the proposed method. The robustness and effectiveness of the proposed method are demonstrated by solving a large-scale HENS problem involving 39 process streams, and the results obtained are better than those previously published in the literature.

  14. A run-around heat exchanger system to improve the energy efficiency of a home appliance using hot water

    International Nuclear Information System (INIS)

    Park, Jae Sung; Jacobi, Anthony M.


    A significant portion of the energy consumed by many home appliances using hot water is used to heat cold supply water. Such home appliances generally are supplied water at a temperature lower than the ambient temperature, and the supply water is normally heated to its maximum operating temperature, often using natural gas or an electrical heater. In some cases, it is possible to pre-heat the supply water and save energy that would normally be consumed by the natural gas or electrical heater. In order to save the energy consumed by an appliance using water heater, a run-around heat exchanger system is used to transfer heat from the ambient to the water before an electrical heater is energized. A simple model to predict the performance of this system is developed and validated, and the model is used to explore design and operating issues relevant to the run-around heat exchanger system. Despite the additional power consumption by the fan and pump of the run-around heat exchanger system, the experimental data and analysis show that for some systems the overall energy efficiency of the appliance can be improved, saving about 6% of the energy used by the baseline machine.

  15. Impact of waste heat recovery systems on energy efficiency improvement of a heavy-duty diesel engine (United States)

    Ma, Zheshu; Chen, Hua; Zhang, Yong


    The increase of ship's energy utilization efficiency and the reduction of greenhouse gas emissions have been high lightened in recent years and have become an increasingly important subject for ship designers and owners. The International Maritime Organization (IMO) is seeking measures to reduce the CO2 emissions from ships, and their proposed energy efficiency design index (EEDI) and energy efficiency operational indicator (EEOI) aim at ensuring that future vessels will be more efficient. Waste heat recovery can be employed not only to improve energy utilization efficiency but also to reduce greenhouse gas emissions. In this paper, a typical conceptual large container ship employing a low speed marine diesel engine as the main propulsion machinery is introduced and three possible types of waste heat recovery systems are designed. To calculate the EEDI and EEOI of the given large container ship, two software packages are developed. From the viewpoint of operation and maintenance, lowering the ship speed and improving container load rate can greatly reduce EEOI and further reduce total fuel consumption. Although the large container ship itself can reach the IMO requirements of EEDI at the first stage with a reduction factor 10% under the reference line value, the proposed waste heat recovery systems can improve the ship EEDI reduction factor to 20% under the reference line value.

  16. Energy conservation in the earth's crust and climate change. (United States)

    Mu, Yao; Mu, Xinzhi


    Among various matters which make up the earth's crust, the thermal conductivity of coal, oil, and oil-gas, which are formed over a long period of geological time, is extremely low. This is significant to prevent transferring the internal heat of the earth to the thermal insulation of the surface, cooling the surface of the earth, stimulating biological evolution, and maintaining natural ecological balance as well. Fossil energy is thermal insulating layer in the earth's crust. Just like the function of the thermal isolation of subcutaneous fatty tissue under the dermis of human skin, it keeps the internal heat within the organism so it won't be transferred to the skin's surface and be lost maintaining body temperature at low temperatures. Coal, oil, oil-gas, and fat belong to the same hydrocarbons, and the functions of their thermal insulation are exactly the same. That is to say, coal, oil, and oil-gas are just like the earth's "subcutaneous fatty tissue" and objectively formed the insulation protection on earth's surface. This paper argues that the human large-scale extraction of fossil energy leads to damage of the earth's crust heat-resistant sealing, increasing terrestrial heat flow, or the heat flow as it is called, transferring the internal heat of the earth to Earth's surface excessively, and causing geotemperature and sea temperature to rise, thus giving rise to global warming. The reason for climate warming is not due to the expansion of greenhouse gases but to the wide exploitation of fossil energy, which destroyed the heat insulation of the earth's crust, making more heat from the interior of the earth be released to the atmosphere. Based on the energy conservation principle, the measurement of the increase of the average global temperature that was caused by the increase of terrestrial heat flow since the Industrial Revolution is consistent with practical data. This paper illustrates "pathogenesis" of climate change using medical knowledge. The

  17. Integrating Waste Heat from CO2 Removal and Coal-Fired Flue Gas to Increase Plant Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Irvin, Nick [Southern Company Services, Inc., Birmingham, AL (United States); Kowalczyk, Joseph [Southern Company Services, Inc., Birmingham, AL (United States)


    In project DE-FE0007525, Southern Company Services demonstrated heat integration methods for the capture and sequestration of carbon dioxide produced from pulverized coal combustion. A waste heat recovery technology (termed High Efficiency System) from Mitsubishi Heavy Industries America was integrated into an existing 25-MW amine-based CO2 capture process (Kansai Mitsubishi Carbon Dioxide Recovery Process®1) at Southern Company’s Plant Barry to evaluate improvements in the energy performance of the pulverized coal plant and CO2 capture process. The heat integration system consists of two primary pieces of equipment: (1) the CO2 Cooler which uses product CO2 gas from the capture process to heat boiler condensate, and (2) the Flue Gas Cooler which uses air heater outlet flue gas to further heat boiler condensate. Both pieces of equipment were included in the pilot system. The pilot CO2 Cooler used waste heat from the 25-MW CO2 capture plant (but not always from product CO2 gas, as intended). The pilot Flue Gas Cooler used heat from a slipstream of flue gas taken from downstream of Plant Barry’s air heater. The pilot also included a 0.25-MW electrostatic precipitator. The 25-MW High Efficiency System operated for approximately six weeks over a four month time period in conjunction with the 25-MW CO2 capture facility at Plant Barry. Results from the program were used to evaluate the technical and economic feasibility of full-scale implementation of this technology. The test program quantified energy efficiency improvements to a host power plant that could be realized due to the High Efficiency System. Through the execution of this project, the team verified the integrated operation of the High Efficiency System and Kansai Mitsubishi Carbon Dioxide Recovery Process®. The ancillary benefits of the High Efficiency System were also quantified, including reduced water consumption

  18. WEXA: exergy analysis for increasing the efficiency of air/water heat pumps - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Gasser, L.; Wellig, B.; Hilfiker, K.


    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) presents the results of a study at the made by the Engineering and Architecture department at the Lucerne University of Applied Sciences and Arts. The subject of the WEXA study (Waermepumpen-Exergie-Analyse - heat pump exergy analysis) is the analysis of the operation of air/water heat-pumps using exergy analysis methods. The basic thermodynamics of heating systems using heat-pumps is discussed. The exergy analyses and exergy balances for the various components and processes of an air/water heat-pump are presented and discussed. Comparisons are presented for heat-pumps with on/off and continuous control systems for their compressors and fans. The paper is concluded with a collection of appendices on the subject.

  19. Combined Heat and Power Systems Technology Development and Demonstration 370 kW High Efficiency Microturbine

    Energy Technology Data Exchange (ETDEWEB)



    The C370 Program was awarded in October 2010 with the ambitious goal of designing and testing the most electrically efficient recuperated microturbine engine at a rated power of less than 500 kW. The aggressive targets for electrical efficiency, emission regulatory compliance, and the estimated price point make the system state-of-the-art for microturbine engine systems. These goals will be met by designing a two stage microturbine engine identified as the low pressure spool and high pressure spool that are based on derivative hardware of Capstone’s current commercially available engines. The development and testing of the engine occurred in two phases. Phase I focused on developing a higher power and more efficient engine, that would become the low pressure spool which is based on Capstone’s C200 (200kW) engine architecture. Phase II integrated the low pressure spool created in Phase I with the high pressure spool, which is based on Capstone’s C65 (65 kW) commercially available engine. Integration of the engines, based on preliminary research, would allow the dual spool engine to provide electrical power in excess of 370 kW, with electrical efficiency approaching 42%. If both of these targets were met coupled with the overall CHP target of 85% total combined heating and electrical efficiency California Air Resources Board (CARB) level emissions, and a price target of $600 per kW, the system would represent a step change in the currently available commercial generation technology. Phase I of the C370 program required the development of the C370 low pressure spool. The goal was to increase the C200 engine power by a minimum of 25% — 250 kW — and efficiency from 32% to 37%. These increases in the C200 engine output were imperative to meet the power requirements of the engine when both spools were integrated. An additional benefit of designing and testing the C370 low pressure spool was the possibility of developing a stand-alone product for possible

  20. Energy efficiency in process plants with emphasis on heat exchanger networks : optimization, thermodynamics and insight

    Energy Technology Data Exchange (ETDEWEB)

    Anantharaman, Rahul


    This thesis focuses on energy recovery system design and energy integration to improve the energy efficiency of process plants. The objectives of this work are to (a) develop a systematic methodology based on thermodynamic principles to integrate energy intensive processes and (b) develop a mathematical programming based approach using thermodynamics and insight for solving industrial sized HENS problems. A novel energy integration methodology, Energy Level Composite Curves (ELCC), has been developed that is a synergy of Exergy Analysis and Composite Curves. ELCC is a graphical tool which provides the engineer with insights on energy integration and this work represents the first methodological attempt to represent thermal, mechanical and chemical energy in a graphical form similar to composite curves for the thermal integration of energy intensive processes. This method provides physical insight to integrate energy sources with sinks. The methodology is useful as a screening tool, functioning as an idea generator prior to the heat and power integration step. A simple energy targeting algorithm is developed to obtain utility targets. The ELCC was applied to a methanol plant to show the efficacy of the methodology.The Sequential Framework, an iterative and sequential methodology for Heat Exchanger Network Synthesis (HENS), is presented in this thesis. The main objective of the Sequential Framework is to solve industrial size problems. The subtasks of the design process are solved sequentially using Mathematical Programming. There are two main advantages of the methodology. First, the design procedure is, to a large extent, automated while keeping significant user interaction. Second, the subtasks of the framework (MILP and NLP problems) are much easier to solve numerically than the MINLP models that have been suggested for HENS. Application of the Sequential Framework to literature examples showed that the methodology generated solutions with total annualized costs

  1. Geothermal heat pumps as one of possibilities of an alternative energy used for objects heating objects in Czech Republic

    International Nuclear Information System (INIS)

    Briza, K.; Bujok, P.; Ryska, J.; Kunz, A.


    The use of geothermal energy for more localised energy requirements is becoming more apparent with the use of geothermal heat pumps. The use of heat from the upper portion of the earth's crust can be useful and efficient method of energy saving. At around 50 m below the earth's surface the ambient temperature fluctuates between around 8-12 grad C. This heat can be used by being transferred to the surface via a loop system using a high-efficiency refrigerant type of material. These systems are also typically more efficient than gas or oil-fired heating systems. They are more energy efficient than air-source heat pumps because they draw heat from, or release heat to, the earth, which has moderate temperatures all the year, rather than to the air. Geothermal heat pumps use the relatively constant temperature of the ground or water several meters below the earth's surface as source of heating and cooling. Geothermal heat pumps are appropriate for retrofit or new homes, where both heating and cooling are desired. In addition to heating and cooling, geothermal heat pumps can provide domestic hot water. They can be used for virtually any home size or lot in any region of the Czech Republic. (authors)

  2. USArray Imaging of Continental Crust in the Conterminous United States (United States)

    Ma, Xiaofei; Lowry, Anthony R.


    The thickness and bulk composition of continental crust provide important constraints on the evolution and dynamics of continents. Crustal mineralogy and thickness both may influence gravity anomalies, topographic elevation, and lithospheric strength, but prior to the inception of EarthScope's USArray, seismic measurements of crustal thickness and properties useful for inferring lithology are sparse. Here we improve upon a previously published methodology for joint inversion of Bouguer gravity anomalies and seismic receiver functions by using parameter space stacking of cross correlations of modeled synthetic and observed receiver functions instead of standard H-κ amplitude stacking. The new method is applied to estimation of thickness and bulk seismic velocity ratio, vP/vS, of continental crust in the conterminous United States using USArray and other broadband network data. Crustal thickness variations are reasonably consistent with those found in other studies and show interesting relationships to the history of North American continental formation. Seismic velocity ratios derived in this study are more robust than in other analyses and hint at large-scale variations in composition of continental crust. To interpret the results, we model the pressure-/temperature-dependent thermodynamics of mineral formation for various crustal chemistries, with and without volatile constituents. Our results suggest that hydration lowers bulk crustal vP/vS and density and releases heat in the shallow crust but absorbs heat in the lowermost crust (where plagioclase breaks down to pyroxene and garnet resulting in higher seismic velocity). Hence, vP/vS variations may provide a useful proxy for hydration state in the crust.

  3. On the potential for BECCS efficiency improvement through heat recovery from both post-combustion and oxy-combustion facilities. (United States)

    Dowell, N Mac; Fajardy, M


    In order to mitigate climate change to no more than 2 °C, it is well understood that it will be necessary to directly remove significant quantities of CO 2 , with bioenergy CCS (BECCS) regarded as a promising technology. However, BECCS will likely be more costly and less efficient at power generation than conventional CCS. Thus, approaches to improve BECCS performance and reduce costs are of importance to facilitate the deployment of this key technology. In this study, the impact of biomass co-firing rate and biomass moisture content on BECCS efficiency with both post- and oxy-combustion CO 2 capture technologies was evaluated. It was found that post-combustion capture BECCS (PCC-BECCS) facilities will be appreciably less efficient than oxy-combustion capture BECCS (OCC-BECCS) facilities. Consequently, PCC-BECCS have the potential to be more carbon negative than OCC-BECCS per unit electricity generated. It was further observed that the biomass moisture content plays an important role in determining the BECCS facilities' efficiency. This will in turn affect the enthalpic content of the BECCS plant exhaust and implies that exhaust gas heat recovery may be an attractive option at higher rates of co-firing. It was found that there is the potential for the recovery of approximately 2.5 GJ heat per t CO 2 at a temperature of 100 °C from both PCC-BECCS and OCC-BECCS. On- and off-site applications for this recovered heat are discussed, considering boiler feedwater pre-heating, solvent regeneration and district heating cases.

  4. Case Study of a Low-Energy District Heating Network in Energy-Efficient Settlements in Denmark

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Christensen, Jørgen Erik

    for low-energy houses in Denmark was investigated. We considered the influence of the human behavior on the energy demand, the importance of the degree of buildings connected to the network and a socio-economical comparison with ground source heat pumps. In the North European climate, the human behavior...... customer in a cost-effective and environmentally friendly way in areas with linear heat density down to 0.20 MWh/(m.year). This suggests that the mandatory connection of low-energy buildings to DH in specific areas, by means of detailed energy planning, would improve the energy efficiency and the overall...

  5. Efficiency Analysis of Technological Methods for Reduction of NOx Emissions while Burning Hydrocarbon Fuels in Heat and Power Plants

    Directory of Open Access Journals (Sweden)

    S. M. Kabishov


    Full Text Available The paper contains a comparative efficiency analysis pertaining to application of existing technological methods for suppression of nitric oxide formation in heating boilers of heat generators. A special attention has been given to investigation of NOx  emission reduction while burning hydrocarbon fuel with the help of oxygen-enriched air. The calculations have demonstrated that while enriching oxidizer with the help of oxygen up to 50 % (by volume it is possible to reduce volume of NOx formation (while burning fuel unit by 21 %.

  6. Procedures for Efficient and Economic Recovery of Heat for Reuse in Batch Processes for Cleaning

    DEFF Research Database (Denmark)

    Qvale, Einar Bjørn


    (TES) may be required to achieve these improvements. Further improvements may be achieved if there is a need, in the plant, for heating water at low-or-medium-level temperatures for cleaning purposes and there are significant quantities of medium-to-lowtemperature heat recoverable. Such conditions...

  7. Improving efficiency of heat pumps by use of zeotropic mixtures for different temperature glides

    DEFF Research Database (Denmark)

    Zühlsdorf, Benjamin; Jensen, Jonas Kjær; Cignitti, Stefano


    The present study demonstrates the optimization of a heat pump for an application with a large temperature glide on the sink and a smaller temperature glide on the source side. The study includes a simulation of a heat pump cycle for all possible binary mixtures from a list of 14 natural...

  8. Cost Efficient Optimization Based Supervisory Controller for Supermarket Subsystems with Heat Recovery

    DEFF Research Database (Denmark)

    Minko, Tomasz; Wisniewski, Rafal; Bendtsen, Jan Dimon


    In this paper, we present a simple modelling approach for a thermal system, which consists of heating, ventilation, air conditioning system (HVAC) and a vapor compression cycle (VCC) system, with one loop heat recovery. In addition a simple model for water tank is presented, in which the reclaimed...

  9. Heat pumps - Even more efficient and quieter; Waermepumpen - noch effizienter und leiser

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, T.


    These comprehensive proceedings contain nine presentations made at the 10th Conference held by the Swiss Research Programme on Environmental Heat, Combined Heat and Power Generation (CHP) and Refrigeration in Burgdorf, Switzerland in June 2003. In a paper by Stefen Bertsch, Peter Hubacher and Prof. Dr. Max Ehrbar, methods of freeing the evaporators used in air-water heat pumps of ice is examined, Prof. Dr. Thomas Afjei introduces standardised schematics for heat pump installations, Dr. Hans Rudolf Graf presents the results of research into noise reduction for air-water heat pumps and Dr. Esfandiar Shafai reports on pulse-width-modulation for small heat pumps. A further paper covers the use of ammonia in small heat pumps (Ewald Geisser). Dr. Martin Zogg looks back on 10 years of heat pump research at the Swiss Federal Office of Energy whilst Prof. Dr. Thomas Kopp takes a look at the future activities of the programme. Finally, Prof. Dr. Max Ehrbar discusses strategies for and the implementation of pilot and demonstration plants.

  10. Developing a strategy for improving efficiency in the heating sector in central and eastern Europe

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, A.S. [World Bank, Washington, DC (United States)


    Heating is a vital energy service in Central and Eastern Europe, but the current delivery mechanisms are riddled with problems. District heating (DH) in its present technical form and with the present management structures is an inefficient system which produces expensive heat. Customers cannot control it and react to overheating by opening windows, even in winter. DH facilities together with other forms of individual heating are responsible for air pollution, causing severe impacts on the health of urban residents. The issues relating to DH are discussed, the first World Bank activities and experiences with projects in Poland are analyzed, and the cornerstones of a strategy to support future World Bank financing and the development of sound heating policies in CEE are presented.

  11. Study of a pilot photovoltaic-electrolyser-fuel cell power system for a geothermal heat pump heated greenhouse and evaluation of the electrolyser efficiency and operational mode

    Directory of Open Access Journals (Sweden)

    Ileana Blanco


    Full Text Available The intrinsic factor of variability of renewable energy sources often limits their broader use. The photovoltaic solar systems can be provided with a power back up based on a combination of an electrolyser and a fuel cell stack. The integration of solar hydrogen power systems with greenhouse heating equipment can provide a possible option for powering stand-alone greenhouses. The aim of the research under development at the experimental farm of Department of Agro-Environmental Sciences of the University of Bari Aldo Moro is to investigate on the suitable solutions of a power system based on photovoltaic energy and on the use of hydrogen as energy vector, integrated with a ground source heat pump for greenhouse heating in a self sustained way. The excess energy produced by a purpose-built array of solar photovoltaic modules supplies an alkaline electrolyser; the produced hydrogen gas is stored in pressured storage tank. When the solar radiation level is insufficient to meet the heat pump power demand, the fuel cell starts converting the chemical energy stored by the hydrogen fuel into electricity. This paper reports on the description of the realised system. Furthermore the efficiency and the operational mode of the electrolyser were evaluated during a trial period characterised by mutable solar radiant energy. Anyway the electrolyser worked continuously in a transient state producing fluctuations of the hydrogen production and without ever reaching the steady-state conditions. The Faradic efficiency, evaluated by means of an empirical mathematic model, highlights that the suitable working range of the electrolyser was 1.5÷2.5 kW and then for hydrogen production more than 0.21 Nm3h–1.

  12. Profiling planktonic foraminiferal crust formation

    NARCIS (Netherlands)

    Steinhardt, Juliane; de Nooijer, Lennart; Brummer, Geert Jan; Reichart, Gert Jan


    Planktonic foraminifera migrate vertically through the water column during their life, thereby growing and calcifying over a range of depth-associated conditions. Some species form a calcite veneer, crust, or cortex at the end of their lifecycle. This additional calcite layer may vary in structure,

  13. Use of biomass for clean and efficient production of heat and power. Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Glarborg, P.; Lans, R. van der; Frandsen, J.B.F.; Johnsson, J.E.; Jensen, A.; Kiil, S.; Dam-Johansen, K.


    The present EFP98 project is the second phase of a long-term, strategic research project, the aim of which is to facilitate the use of significant amounts of biomass in the production of power and heat. The project deals with combustion and emission issues related to the use of biomass, specifically combustion of straw on a grate and wet flue gas desulphurization. A mathematical model for combustion of straw on a grate is developed as a tool to improve the understanding of this process. The model includes heat transfer to and in the bed as well as pyrolysis and char oxidation. To verify the model and to obtain a better understanding of fixed-bed straw combustion, a number of bench-scale laboratory experiments have been conducted at TNO in Holland. Predicted combustion rates and bed temperatures were in fairly good agreement with experimental fixed-bed data. A parameter analysis has identified the sensitivity of modeling predictions towards important parameters in the model. Measuring programs on straw firing have been conducted at Enstedvaerket and Masnedoe. Measuring results include gas temperature and gas composition (O{sub 2}, CO{sub 2}, CO. SO{sub 2}, NO) from different positions in the boiler. Data from Masnedoe include also results from co-firing of straw with other biomass fuels (25-35%). The results indicate that co-firing in the quantities does not significantly affect emissions. Nitrogen oxides emissions from Masnedoevaerket were found to be significantly higher than those of Ensted. The work on wet flue gas desulphurization on aimed to provide the information necessary to optimize and further develop the process. The main focus was fuel and sorbent flexibility, use of the waste product from the semi-dry FGD process as a sorbent in wet FGD, and ways of optimizing the Wet FGD process with respect to a high degree of desulphurization, a low content of residual limestone in the gypsum and a continuous steady state operation of the FGD plant. Laboratory

  14. The influence of operating temperature on the efficiency of a combined heat and power fuel cell plant (United States)

    Au, S. F.; McPhail, S. J.; Woudstra, N.; Hemmes, K.

    It is generally accepted that the ideal operating temperature of a molten carbonate fuel cell (MCFC) is 650 °C. Nevertheless, when waste heat utilization in the form of an expander and steam production cycle is introduced in the system, another temperature level might prove more productive. This article is a first attempt to the optimization of MCFC operating temperatures of a MCFC system by presenting a case study in which the efficiency of a combined heat and power (CHP) plant is analyzed. The fuel cell plant under investigation is designed around a 250 kW-class MCFC fuelled by natural gas, which is externally reformed by a heat exchange reformer (HER). The operating temperature of the MCFC is varied over a temperature range between 600 and 700 °C while keeping the rest of the system the same as far as possible. Changes in energetic efficiency are given and the causes of these changes are further analyzed. Furthermore, the exergetic efficiencies of the system and the distribution of exergy losses in the system are given. Flowsheet calculations show that there is little dependency on the temperature in the first order. Both the net electrical performance and the overall exergetic performance show a maximum at approximately 675 °C, with an electrical efficiency of 51.9% (LHV), and an exergy efficiency of 58.7%. The overall thermal efficiency of this CHP plant increases from 87.1% at 600 °C to 88.9% at 700 °C. Overall, the change in performance is small in this typical range of MCFC operating temperature.

  15. Energy Efficiency and Sustainability Evaluation of Space and Water Heating in Urban Residential Buildings of the Hot Summer and Cold Winter Zone in China

    Directory of Open Access Journals (Sweden)

    Xiao Chen


    Full Text Available With the urbanization process of the hot summer and cold winter (HSCW zone in China, the energy consumption of space and water heating in urban residential buildings of the HSCW zone has increased rapidly. This study presents the energy efficiency and sustainability evaluation of various ways of space and water heating taking 10 typical cities in the HSCW zone as research cases. Two indicators, primary energy efficiency (PEE and sustainability index based on exergy efficiency, are adopted to perform the evaluation. Models for the energy and total exergy efficiencies of various space and water heating equipment/systems are developed. The evaluation results indicate that common uses of electricity for space and water heating are the most unsustainable ways of space and water heating. In terms of PEE and sustainability index, air-source heat pumps for space and water heating are suitable for the HSCW zone. The PEE and sustainability index of solar water heaters with auxiliary electric heaters are greatly influenced by local solar resources. Air-source heat pump assisted solar hot water systems are the most sustainable among all water heating equipment/systems investigated in this study. Our works suggest the key potential for improving the energy efficiency and the sustainability of space and water heating in urban residential buildings of the HSCW zone.

  16. Evaporation front compared with crust thickness in potato deep-fat frying. (United States)

    Lioumbas, John S; Karapantsios, Thodoris D


    The various theoretical approaches that have been proposed for modeling heat and mass transport during deep-fat frying of potatoes provide a rather ambiguous view of the relation between the propagation of the evaporation front inside the food and the evolution of crust thickness. This can be partly attributed to the unavailability of detailed experimental information concerning the temperature field inside the developing crust to validate the models. The objective of the present work is to experimentally study the relation between crust thickness evolution and evaporation front propagation and how this varies with frying conditions. To achieve this goal, a special device has been constructed that permits (1) only 1 side of a potato stick to be exposed to hot oil, and (2) accurate and stable placement of miniature thermocouples in prescribed positions under but very close to the potato surface. Temperature recordings inside the developing crust allowed identification of different heating regimes during frying and a rough estimation of the evaporation front propagation. In addition, crust thickness was determined at intermittent time intervals by 2 independent methods (1) microphotography and (2) a micrometer. Comparison of the evaporation front propagation with crust thickness evolution indicates an interrelationship roughly up to the end of the boiling regime (bubble-end point). After this moment, the propagation of the evaporation front is faster than the evolution of crust thickness. Understanding the role of parameters that determine crust formation is of paramount importance since crust characteristics such as thickness and texture dictate the sensory perception of fried foods. This study aims to quantify the relationship between such parameters (that is, crust evolution and the propagation of the evaporation front inside the food) and to examine how frying conditions (oil temperature and frying duration) affect it. In addition, the present findings may be of

  17. Experimental study on Rankine cycle evaporator efficiency intended for exhaust waste heat recovery of a diesel engine

    Directory of Open Access Journals (Sweden)

    Milkov Nikolay


    Full Text Available The paper pressents an experimental study of Rankine cycle evaporator efficiency. Water was chosen as the working fluid in the system. The experimental test was conducted on a test bench equipped with a burner charged by compressed fresh air. Generated exhaust gases parameters were previously determined over the diesel engine operating range (28 engine operating points were studied. For each test point the working fluid parameters (flow rate and evaporating pressure were varied. Thus, the enthalpy flow through the heat exchanger was determined. Heat exchanger was designed as 23 helical tubes are inserted. On the basis of the results, it was found out that efficiency varies from 25 % to 51,9 %. The optimal working fluid pressure is 20 bar at most of the operating points while the optimum fluid mass flow rate varies from 2 g/s to 10 g/s.

  18. Low temperature heat from natural gas. Life cycle analysis for efficient systems

    International Nuclear Information System (INIS)

    Zogg, M.


    A life cycle analysis drawn up on behalf of the Swiss Federal Office of Energy shows that the combined cycle power plant + heat pump (GuD-WP) combination produces less greenhouse effect and makes only about half the contribution to summer smog formation as the operation of heat pumps with the power mix habitually used in Western Europe today. In the co-generation unit + heat pump (BHKW-WP) combination, the environmental impact shows the same values as in current West European power generation

  19. Microencapsulated Phase Change Materials in Solar-Thermal Conversion Systems: Understanding Geometry-Dependent Heating Efficiency and System Reliability. (United States)

    Zheng, Zhaoliang; Chang, Zhuo; Xu, Guang-Kui; McBride, Fiona; Ho, Alexandra; Zhuola, Zhuola; Michailidis, Marios; Li, Wei; Raval, Rasmita; Akhtar, Riaz; Shchukin, Dmitry


    The performance of solar-thermal conversion systems can be improved by incorporation of nanocarbon-stabilized microencapsulated phase change materials (MPCMs). The geometry of MPCMs in the microcapsules plays an important role for improving their heating efficiency and reliability. Yet few efforts have been made to critically examine the formation mechanism of different geometries and their effect on MPCMs-shell interaction. Herein, through changing the cooling rate of original emulsions, we acquire MPCMs within the nanocarbon microcapsules with a hollow structure of MPCMs (h-MPCMs) or solid PCM core particles (s-MPCMs). X-ray photoelectron spectroscopy and atomic force microscopy reveals that the capsule shell of the h-MPCMs is enriched with nanocarbons and has a greater MPCMs-shell interaction compared to s-MPCMs. This results in the h-MPCMs being more stable and having greater heat diffusivity within and above the phase transition range than the s-MPCMs do. The geometry-dependent heating efficiency and system stability may have important and general implications for the fundamental understanding of microencapsulation and wider breadth of heating generating systems.

  20. Numerical modelling of methane oxidation efficiency and coupled water-gas-heat reactive transfer in a sloping landfill cover. (United States)

    Feng, S; Ng, C W W; Leung, A K; Liu, H W


    Microbial aerobic methane oxidation in unsaturated landfill cover involves coupled water, gas and heat reactive transfer. The coupled process is complex and its influence on methane oxidation efficiency is not clear, especially in steep covers where spatial variations of water, gas and heat are significant. In this study, two-dimensional finite element numerical simulations were carried out to evaluate the performance of unsaturated sloping cover. The numerical model was calibrated using a set of flume model test data, and was then subsequently used for parametric study. A new method that considers transient changes of methane concentration during the estimation of the methane oxidation efficiency was proposed and compared against existing methods. It was found that a steeper cover had a lower oxidation efficiency due to enhanced downslope water flow, during which desaturation of soil promoted gas transport and hence landfill gas emission. This effect was magnified as the cover angle and landfill gas generation rate at the bottom of the cover increased. Assuming the steady-state methane concentration in a cover would result in a non-conservative overestimation of oxidation efficiency, especially when a steep cover was subjected to rainfall infiltration. By considering the transient methane concentration, the newly-modified method can give a more accurate oxidation efficiency. Copyright © 2017. Published by Elsevier Ltd.

  1. Determination of energy efficiency for water heating in eight South African hotels

    CSIR Research Space (South Africa)

    Machete, Fannie


    Full Text Available This study presents a characterization framework for energy efficient hotels. It builds on existing frameworks of energy efficiency and the adopted characterization framework advances from the input-output framework. The theoretical framework...

  2. High Efficiency SiC/SiC Composite Heat Exchanger Structures, Phase I (United States)

    National Aeronautics and Space Administration — Scramjet propulsion systems for future hypersonic aerospace vehicles will be subjected to heating rates far greater than current materials can manage. In order to...

  3. Low-energy district heating in energy-efficient building areas

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro; Christensen, Jørgen Erik


    This paper presents an innovative low-energy district heating (DH) concept based on low-temperature operation. The decreased heating demand from low-energy buildings affects the cost-effectiveness of traditionally-designed DH systems, so we carried out a case study of the annual energy performance...... design, and operational temperature and pressure. In the north-European climate, we found that human behaviour can lead to 50% higher heating demand and 60% higher heating power than those anticipated in the reference values in the standard calculations for energy demand patterns in energy...... system that fully relies on renewable energy needs substantial capital investment, but in the long term this is sustainable from the environmental and socio-economic points of view. Having demonstrated the value of the low-energy DH concept, we evaluated various possible designs with the aim of finding...

  4. Galenicals in the treatment of crusted scabies

    Directory of Open Access Journals (Sweden)

    Sugathan P


    Full Text Available Crusted scabies is rare. It is a therapeutic challenge, as the common drugs used against scabies are unsatisfactory. The successful use of galenicals in a 10-year-old girl with crusted scabies is reported.

  5. Enhanced high intensity focused ultrasound heat deposition for more efficient hemostasis (United States)

    Labuda, Cecille Pemberton

    High intensity focused ultrasound (HIFU) is currently being developed for hemorrhage control since it provides rapid energy deposition in the form of heat in the HIFU focal region. When the HIFU focus is targeted on soft tissue wounds, the resulting elevation of tissue temperature cauterizes the tissues thus stopping the bleeding. If HIFU is targeted near blood vessels with millimeter-range diameter, the rate of heat deposition is limited by loss of heat to the blood flow. Maximizing the local heat deposition is important for the achievement of HIFU-induced hemorrhage control, or "hemostasis", near large vessels. In this study, the effect of a fiber device on the heat deposition in the HIFU focal region is investigated in tissue-mimicking flow phantoms with liquid albumen as the heat-sensitive denaturing flow fluid. The effect of the embedded fiber on albumen coagulation in the flow phantom is compared to the degree and rate of albumen coagulation when no fiber is present. The effect of the fiber device on the size of lesions formed in a heat-sensitive tissue-mimicking phantom is also investigated. Finally, finite difference time domain simulations are performed to determine the heat deposition in a tissue-mimicking phantom with a nylon disc embedded and a phantom with the nylon disc removed. The results of this study are quite promising for the possibility of increased efficacy of hemostasis for such a device in concert with HIFU in vessel-containing tissue volumes where HIFU alone is not completely effective.


    Directory of Open Access Journals (Sweden)

    S. N. Osipov


    Full Text Available Rise in comfort and inhabitation safety is one of the main requirements of the general maintenance, reconstruction of the old and construction of the new residential houses. One of the essential factors of it is substitution in the household hot-water preparing sources: from the individual domestic gas  water-heaters to  the common  entire-building hot-water supply at the expense of the centralized heat supply. Extremely erratic hot-water daily consumption by tenants leads to the necessity of sharp increase in central heat-supply level during a few hours of the day, which requires a significant increase of the source heat-power. On that score, the authors propose to direct a significant part (up to 50 % of the centralized heating and ventilation heat power-consumption to the hot water preparation during the period of short-term hot water consumption peak.Substitution  of  the  individual  domestic  gas  water-heaters  with  the  common  entirebuilding hot-water supply releases a huge amount of natural gas which can be utilized not only for production of the necessary heat power but as well for electric power producing. This substitution is especially advantageous if heat-power is delivered to the residential area from a НРС where significant part of heat especially in a relatively warm season of the year is thrown out into the air. The content of the article is based on several patents received earlier.

  7. The efficiency of night insulation using aerogel-filled polycarbonate panels during the heating season (United States)

    Adelsberger, Kathleen

    Energy is the basis for modern life. All modern technology from a simple coffee maker to massive industrial facilities is powered by energy. While the demand for energy is increasing, our planet is suffering from the consequences of using fossil fuels to generate electricity. Therefore, the world is looking at clean energy and solar power to minimize this effect on our environment. However, saving energy is extremely important even for clean energy. The more we save the less we have to generate. Heat retention in buildings is one step towards achieving passive heating. Therefore, efforts are made to prevent heat from escaping buildings through the glass during cold nights. Movable insulation is a way to increase the insulation value of the glass to reduce heat loss towards the outdoor. This thesis examines the performance of the aerogel-filled polycarbonate movable panels in the Ecohawks building, a building located on the west campus of The University of Kansas. Onsite tests were performed using air and surface temperature sensors to determine the effectiveness of the system. Computer simulations were run by Therm 7.2 simulation software to explore alternative design options. A cost analysis was also performed to evaluate the feasibility of utilizing movable insulation to reduce the heating bills during winter. Results showed that sealed movable insulation reduces heat loss through the glazing by 67.5%. Replacing aerogel with XPS panels reduces this percentage to 64.3%. However, it reduces the cost of the insulation material by 98%.

  8. Application of optimization for improvement of the efficiency of louvered-fin compact heat exchangers

    Directory of Open Access Journals (Sweden)

    Diego Amorim Caetano Souza

    Full Text Available Abstract A few decades ago, the product development process was just based on a trial and error procedure, and the designer's experience. The need for a new way to design and manufacture more economical and sustainable products corroborates increasingly to a new vision of how to create new products for the benefit of society. Modern numerical tools allow greater knowledge about the physical phenomena involved in engineering problems and enable cost reduction with trials and time of manufacture and projection. Among the equipment that can be mentioned where numerical simulation is used, can be found heat exchangers, which are capable of accomplishing the heat transfer between two fluid medias with different temperatures. Within the range of existing exchangers, this work will address a compact model with louvered fins, widely used in the automotive and aerospace industries, mainly due to their high thermal exchange surface vs occupied volume ratio. The heat exchanger surface is analised using computational fluid dynamics tecniques disposable in the commercial code ANSYS CFX14® to reproduce the flow at service condition. Genetic optimization routines are used to increase the performance of heat exchanger. As a result, a heat transfer surface is obtained with about a 25% better performance according to the selected objective function. The dimensionless factor of the convective heat transfer coefficient (Colburn factor, j and the friction factor (Fanning factor, f used in (Wang et al.,1998, are employed for simulation. Experimental data are also used for validation.

  9. Efficiency potentials of heat pumps with combined heat and power. For maximum reduction of CO2 emissions and for electricity generation from fossil fuels with CO2 reduction in Switzerland

    International Nuclear Information System (INIS)

    Rognon, F.


    This comprehensive report for the Swiss Federal Office of Energy (SFOE) takes a look at how the efficiency potential of heat pumps together with combined heat and power systems can help provide a maximum reduction of CO 2 emissions and provide electricity generation from fossil fuel in Switzerland together with reductions in CO 2 emissions. In Switzerland, approximately 80% of the low-temperature heat required for space-heating and for the heating-up of hot water is produced by burning combustibles. Around a million gas and oil boilers were in use in Switzerland in 2000, and these accounted for approximately half the country's 41.1 million tonnes of CO 2 emissions. The authors state that there is a more efficient solution with lower CO 2 emissions: the heat pump. With the enormous potential of our environment it would be possible to replace half the total number of boilers in use today with heat pumps. This would be equivalent to 90 PJ p.a. of useful heat, or 500,000 systems. The power source for heat pumps should come from the substitution of electric heating systems (electric resistor-based systems) and from the replacement of boilers. This should be done by using combined heat and power systems with full heat utilisation. This means, according to the authors, that the entire required power source can be provided without the need to construct new electricity production plants. The paper examines and discusses the theoretical, technical, market and realisable potentials

  10. Effects of heating height on flame appearance, temperature field and efficiency of an impinging laminar jet flame used in domestic gas stoves

    International Nuclear Information System (INIS)

    Hou, S.-S.; Ko, Y.-C.


    Laminar jet flames are used in most domestic gas burners. However, the literature on combustion characteristics and thermal efficiencies of a single laminar impinging jet flame is very limited. Heating height is a significant operating parameter of a domestic gas stove, but it has received little attention in the literature. In this study, our aim is to simulate and examine the effect of heating height on the flame characteristics of a domestic gas stove. We emphasize the importance of heating height on flame structure, temperature distribution and thermal efficiency for low-Reynolds-number fuel-rich methane-air flames impinging normal to a plane surface, which has not been documented yet. Results show that flame structure, temperature distribution and thermal efficiency are greatly influenced by the heating height. With increasing heating height, the thermal efficiency first increases to a maximum value and then decreases. An optimum heating height, identified by the widest high temperature zone and the highest thermal efficiency, is achieved under the condition of Type-C flame burning, in which both the inner premixed flame and outer diffusion flame are open and diverge. Furthermore, we find that the optimum heating height increases with increasing methane concentration or injection velocity. Note that the maximum thermal efficiency occurs when the heating height is slightly lower than the tip of the inner rich premixed flame. This important characteristic can be applied to the design of domestic gas stoves, and it was not found in the available published work

  11. Chronology of early lunar crust

    International Nuclear Information System (INIS)

    Dasch, E.J.; Nyquist, L.E.; Ryder, G.


    The chronology of lunar rocks is summarized. The oldest pristine (i.e., lacking meteoritic contamination of admixed components) lunar rock, recently dated with Sm-Nd by Lugmair, is a ferroan anorthosite, with an age of 4.44 + 0.02 Ga. Ages of Mg-suite rocks (4.1 to 4.5 Ga) have large uncertainties, so that age differences between lunar plutonic rock suites cannot yet be resolved. Most mare basalts crystallized between 3.1 and 3.9 Ga. The vast bulk of the lunar crust, therefore, formed before the oldest preserved terrestrial rocks. If the Moon accreted at 4.56 Ga, then 120 Ma may have elapsed before lunar crust was formed

  12. Efficiency Analysis of the Main Components of a Vertical Closed-Loop System in a Borehole Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Cristina Sáez Blázquez


    Full Text Available In vertical closed-loop systems, it is common to use single or double U-tube heat exchangers separated by longitudinal spacers. In addition, the helical-shaped pipe is another configuration that requires lower drilling lengths but it is less used. The aim of the present research is to study the influence of these components on the total efficiency of a borehole heat exchanger (BHE. Thus, the differences between using single/double U-tubes (with or without spacers and helical pipes are analysed in terms of efficiency. Through different laboratory tests, a small vertical closed-loop system was simulated in order to analyse all these possible configurations. The grouting materials and the temperatures of the ground were modified at the same time in these tests. Regarding the heat exchange process between the ground and the heat carrier fluid, it must be highlighted that the best results were obtained for the helical-shaped pipe configuration. Some of the improvements offered by this heat exchanger typology with respect to the vertical configuration is that a lower drilling depth is required even it requires a larger diameter. This leads to significant economic savings in the performing drilling process. Finally, it is also worth noting the importance of using spacers in vertical U-tubes and that no improvements have been found regarding the use of single or double configuration of U-tubes. Thanks to the laboratory results derived from this study it is possible to establish the optimum behaviour pattern for the entire vertical closed-loop systems.

  13. Physics of the earth crust

    International Nuclear Information System (INIS)

    Lauterbach, R.


    This book deals in 12 chapters, amongst other things, with the subjects: Structure of the crust and the upper earth mantle, geology and geophysics of sea beds, satellite and aero-methods of geophysics, state of the art of geothermal research, geophysical potential fields and their anomalies, applied seismology, electrical methods of geophysics, geophysics in engineering and rock engineering, borehole geophysics, petrophysics, and geochemistry. (RW) [de

  14. High Efficiency - Reduced Emissions Boiler Systems for Steam, Heat, and Processing (United States)


    to a controller or DAQ) IR: Infra - red MODBUS: De facto standard communication protocol NAVFAC: Naval Facilities Engineering Command NDIR...Indeed, exhaust gases from each burner mix, so that stack measurements do not carry information on each burner’s combustion efficiency. Large, single... combustion efficiency. Combustion efficiency is a measurement of performance of the combustion process independent of other factors contributing to the

  15. Building material characterization by using IR thermography for efficient heating systems (United States)

    Bison, Paolo; Grinzato, Ermanno


    Thermography is excellent for a fast characterisation of building materials, both at laboratory or in situ. A great advantage is the possibility to analyse many samples at the same conditions and time. A technique has been applied for new materials, oriented to radiating floor systems, evaluating different approaches. Samples are submitted to a stepwise, uniform heating. Surface excess temperature is recorded by thermography evaluating thermal inertia. At first, thermal diffusivity has been measured using a modified version of the Flash Method, then applied on a single face, for in situ application. Heat capacity and thermal conductivity have been inferred for each samples by definitions and the independent measure of the volumic mass.

  16. Efficient on-chip hotspot removal combined solution of thermoelectric cooler and mini-channel heat sink

    International Nuclear Information System (INIS)

    Hao, Xiaohong; Peng, Bei; Xie, Gongnan; Chen, Yi


    Highlights: • A combined solution of thermoelectric cooler (TEC) and mini-channel heat sink to remove the hotspot of the chip has been proposed. • The TEC's mathematical model is established to assess its work performance. • A comparative study on the proposed efficient On-Chip Hotspot Removal Combined Solution. - Abstract: Hotspot will significantly degrade the reliability and performance of the electronic equipment. The efficient removal of hotspot can make the temperature distribution uniform, and ensure the reliable operation of the electronic equipment. This study proposes a combined solution of thermoelectric cooler (TEC) and mini-channel heat sink to remove the hotspot of the chip in the electronic equipment. Firstly, The TEC's mathematical model is established to assess its work performance under different boundary conditions. Then, the hotspot removal capability of the TEC is discussed for different cooling conditions, which has shown that the combined equipment has better hotspot removal capability compared with others. Finally, A TEC is employed to investigate the hotspot removal capacity of the combined solution, and the results have indicated that it can effectively remove hotspot in the diameter of 0.5 mm, the power density of 600W/cm 2 when its working current is 3A and heat transfer thermal resistance is 0 K/W.

  17. PhD Thesis Summary: Energy Efficient Multistage Zeolite Drying for Heat-Sensitive Products

    NARCIS (Netherlands)

    Djaeni, M.; Boxtel, van A.J.B.


    Although drying takes a significant part of the total energy usage in industry, currently available drying technology is often not efficient in terms of energy consumption. Generally, the energy efficiency for drying processes ranges between 20 and 60% depending on the dryer type and product to be

  18. Learning energy efficiency: experience curves for household appliances and space heating, cooling, and lighting technologies

    NARCIS (Netherlands)

    Weiss, M.|info:eu-repo/dai/nl/156419912; Junginger, H.M.|info:eu-repo/dai/nl/202130703; Patel, M.K.|info:eu-repo/dai/nl/18988097X


    Improving demand side energy efficiency is an important strategy for establishing a sustainable energy system. Large potentials for energy efficiency improvements exist in the residential and commercial buildings sector. This sector currently accounts for almost 40% of the European Union’s (EU)

  19. The effect of heating technologies on CO2 and energy efficiency of Dutch greenhouse firms

    NARCIS (Netherlands)

    Oude Lansink, A.G.J.M.; Bezlepkin, I.


    This paper uses Data Envelopment Analysis to compute measures of the efficiency (relative to a frontier) in terms of the use of all inputs as well as for single inputs like CO2 and energy for a sample of greenhouse firms in the Netherlands over the period 1991-1995. These efficiency measures are

  20. Guided design of heating and cooling mains for lower water and energy consumption and increased efficiency

    CSIR Research Space (South Africa)

    Gololo, V


    Full Text Available can allow reaching significant savings. It is also known from power generation and from the bulk chemicals production that the cooling water systems are generally designed with a set of heat exchangers arranged in parallel. This arrangement results...

  1. Efficient Arrangement of Field Coils for Rotational Induction Heating of Nonmagnetic Cylindrical Billets

    Czech Academy of Sciences Publication Activity Database

    Donátová, M.; Karban, P.; Doležel, Ivo


    Roč. 86, č. 1 (2010), s. 83-85 ISSN 0033-2097 Grant - others:GA MŠk(CZ) MEB050807 Institutional research plan: CEZ:AV0Z20570509 Keywords : induction heating * integrodifferential model * electromagnetic field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.242, year: 2010

  2. The role of non-rainfall water on physiological activation in desert biological soil crusts (United States)

    Zheng, Jiaoli; Peng, Chengrong; Li, Hua; Li, Shuangshuang; Huang, Shun; Hu, Yao; Zhang, Jinli; Li, Dunhai


    Non-rainfall water (NRW, e.g. fog and dew), in addition to rainfall and snowfall, are considered important water inputs to drylands. At the same time, biological soil crusts (BSCs) are important components of drylands. However, little information is available regarding the effect of NRW inputs on BSC activation. In this study, the effects of NRW on physiological activation in three BSC successional stages, including the cyanobacteria crust stage (Crust-C), moss colonization stage (Crust-CM), and moss crust stage (Crust-M), were studied in situ. Results suggest NRW inputs hydrated and activated physiological activity (Fv/Fm, carbon exchange, and nitrogen fixation) in BSCs but led to a negative carbon balance and low rates of nitrogen fixation in BSCs. One effective NRW event could hydrate BSCs for 7 h. Following simulated rainfall, the physiological activities recovered within 3 h, and net carbon gain occurred until 3 h after hydration, whereas NRW-induced physiological recovery processes were slower and exhibited lower activities, leading to a negative carbon balance. There were significant positive correlations between NRW amounts and the recovered values of Fv/Fm in all the three BSC stages (p < .001). The thresholds for Fv/Fm activation decreased with BSC succession, and the annual effective NRW events increased with BSC succession, with values of 29.8, 89.2, and 110.7 in Crust-C, Crust-CM and Crust-M, respectively. The results suggest that moss crust and moss-cyanobacteria crust use NRW to prolong metabolic activity and reduce drought stress more efficiently than cyanobacteria crusts. Therefore, these results suggest that BSCs utilize NRW to sustain life while growth and biomass accumulation require precipitation (rainfall) events over a certain threshold.

  3. System efficiency for two-step metal oxide solar thermochemical hydrogen production – Part 2: Impact of gas heat recuperation and separation temperatures

    KAUST Repository

    Ehrhart, Brian D.


    The solar-to-hydrogen (STH) efficiency is calculated for various operating conditions for a two-step metal oxide solar thermochemical hydrogen production cycle using cerium(IV) oxide. An inert sweep gas was considered as the O2 removal method. Gas and solid heat recuperation effectiveness values were varied between 0 and 100% in order to determine the limits of the effect of these parameters. The temperature at which the inert gas is separated from oxygen for an open-loop and recycled system is varied. The hydrogen and water separation temperature was also varied and the effect on STH efficiency quantified. This study shows that gas heat recuperation is critical for high efficiency cycles, especially at conditions that require high steam and inert gas flowrates. A key area for future study is identified to be the development of ceramic heat exchangers for high temperature gas-gas heat exchange. Solid heat recuperation is more important at lower oxidation temperatures that favor temperature-swing redox processing, and the relative impact of this heat recuperation is muted if the heat can be used elsewhere in the system. A high separation temperature for the recycled inert gas has been shown to be beneficial, especially for cases of lower gas heat recuperation and increased inert gas flowrates. A higher water/hydrogen separation temperature is beneficial for most gas heat recuperation effectiveness values, though the overall impact on optimal system efficiency is relatively small for the values considered. © 2016 Hydrogen Energy Publications LLC.

  4. Electricity and heat supply of a settlement at different standards of energy efficiency; Strom- und Waermeversorgung einer Siedlung bei unterschiedlichen Energieeffizienz-Standards

    Energy Technology Data Exchange (ETDEWEB)

    Schuberth, Jens; Tschetschorke, Katja


    The underlying study analyses the ecologic impact and the economic efficiency of several conventional and innovative heat supply systems to provide a quarter heat for space and water heating and electricity for residential and commercial application and for street lighting. Retrofits of buildings change the ratio of demands for electricity and heat. The demand for heat decreases more than the demand for electricity, and the share of distribution losses in heat grids rises. The question is if it is still economically efficient to build or extend local and long-distance district heating networks. Demands for final and primary energy, greenhouse gas emissions and costs (for operation, energy consumption and investments) of the different systems are compared and rated both in charts and tables. A sensitivity analysis includes increasing energy purchasing costs and assesses the possible economic efficiency of the supply systems in future. Another sensitivity analysis estimates how the climate impact of the supply systems for heat and electricity changes if electricity generation becomes less harmful for climate. Additionally, costs for environmental damage - so-called external costs - are internalised in the analysis of economic efficiency. In an overall rating ecologic and economically efficient systems are recommended.

  5. An assessment of efficient water heating options for an all-electric single family residence in a mixed-humid climate. (United States)

    Balke, Elizabeth C; Healy, William M; Ullah, Tania


    An evaluation of a variety of efficient water heating strategies for an all-electric single family home located in a mixed-humid climate is conducted using numerical modeling. The strategies considered include various combinations of solar thermal, heat pump, and electric resistance water heaters. The numerical model used in the study is first validated against a year of field data obtained on a dual-tank system with a solar thermal preheat tank feeding a heat pump water heater that serves as a backup. Modeling results show that this configuration is the most efficient of the systems studied over the course of a year, with a system coefficient of performance (COP sys ) of 2.87. The heat pump water heater alone results in a COP sys of 1.9, while the baseline resistance water heater has a COP sys of 0.95. Impacts on space conditioning are also investigated by considering the extra energy consumption required of the air source heat pump to remove or add heat from the conditioned space by the water heating system. A modified COP sys that incorporates the heat pump energy consumption shows a significant drop in efficiency for the dual tank configuration since the heat pump water heater draws the most heat from the space in the heating season while the high temperatures in the solar storage tank during the cooling season result in an added heat load to the space. Despite this degradation in the COP sys , the combination of the solar thermal preheat tank and the heat pump water heater is the most efficient option even when considering the impacts on space conditioning.

  6. [Nitrogen fixation potential of biological soil crusts in southeast edge of Tengger Desert, Northwest China]. (United States)

    Zhang, Peng; Li, Xin-Rong; Zhang, Zhi-Shan; Pan, Yan-Xia; Liu, Yan-Mei; Su, Jie-Qiong


    Taking three typical types of biological soil crusts (BSCs), i.e., cyanobacterial-algal crust, lichen crust, and moss crust, in the southeast fringe of Tengger Desert as test objects, this paper studied their nitrogen fixation potential, seasonal fluctuation, and responses to the environmental factors from June 2010 to May 2011. During the whole study period, the nitrogenase activity (NA) of the cyanobacterial-algal, lichen, and moss crusts had significant difference, being 14-133, 20-101, and 4-28 micromol x m(-2) x h(-1), respectively, which indicated the critical role of the species composition of BSCs in nitrogen fixation. The NA of the three crust types had similar response characteristics to environmental factors. The NA had less correlation with the precipitation during the study period, but was positively correlated to the spring > summer > winter. The high air temperature in summer and the low air temperature (desert zone had nitrogen fixation capacity throughout the year, and the controlling effects of environmental factors on the nitrogen fixation were hierarchical. Water condition was the key factor affecting the nitrogen fixation rate and duration of the crusts, while under the conditions of sufficient water supply and carbon storage, heat condition dominated the crusts nitrogen fixation rate.

  7. High efficiency bio-hydrogen production from glucose revealed in an inoculum of heat-pretreated landfill leachate sludge

    International Nuclear Information System (INIS)

    Wong, Y.M.; Juan, J.C.; Ting, Adeline; Wu, T.Y.


    Bio-hydrogen is a promising sustainable energy to replace fossil fuels. This study investigated bio-H 2 production from the inoculum of heat-pretreated landfill leachate sludge using glucose as model substrate. The seed sludge pretreated at 65 °C showed the highest amount of H 2 at the optimum condition of pH 6 and 37 °C. The maximum H 2 yield estimated by the modified Gompertz model was 6.43 mol H 2 /mol glucose. The high efficient of H 2 production is thermodynamically feasible with the Gibbs free energy of −34 kJ/mol. This study reveals that pretreated landfill leachate sludge has considerable potential for H 2 production. - Highlights: • Heat retreated landfill leachate sludge revealed high efficient H 2 production. • High efficient H 2 yield, 6.4 mol H 2 /mol glucose. • The synergisms between H 2 -producing bacteria may responsible for the high H 2 yield. • High H 2 yield is thermodynamically feasible with Gibbs free energy of −34 kJ/mol

  8. Geothermal source heat pumps under energy services companies finance scheme to increase energy efficiency and production in stockbreeding facilities

    International Nuclear Information System (INIS)

    Borge-Diez, David; Colmenar-Santos, Antonio; Pérez-Molina, Clara; López-Rey, África


    In Europe energy services are underutilized in terms of their potential to improve energy efficiency and reduce external energy dependence. Agricultural and stockbreeding sectors have high potential to improve their energy efficiency. This paper presents an energy model for geothermal source heat pumps in stockbreeding facilities and an analysis of an energy services business case. The proposed solution combines both energy cost reduction and productivity increases and improves energy services company financing scheme. CO 2 emissions drop by 89%, reducing carbon footprint and improving added value for the product. For the two different evaluated scenarios, one including winter heating and one including heating and cooling, high IRR (internal return rate) values are obtained. A sensitivity analysis reveals that the IRR ranges from 10.25% to 22.02%, making the investment attractive. To make the research highly extensible, a sensitivity analysis for different locations and climatic conditions is presented, showing a direct relationship between financial parameters and climatic conditions. A Monte Carlo simulation is performed showing that initial fuel cost and initial investment are the most decisive in the financial results. This work proves that energy services based on geothermal energy can be profitable in these sectors and can increase sustainability, reduce CO 2 emissions and improve carbon footprint. - Highlights: • Geothermal heat pumps are studied to promote industrial energy services. • Geothermal energy in farming facilities improves global competitiveness. • Research shows profitability of low enthalpy geothermal energy services. • Climatic conditions sensitivity analysis reveals IRR ranges from 10.25% to 22.02%. • Added market value for the product as carbon footprint reduction, are achieved

  9. High Efficiency, High Temperature Foam Core Heat Exchanger for Fission Surface Power Systems, Phase II Project (United States)

    National Aeronautics and Space Administration — Fission-based power systems with power levels of 30 to ≥100 kWe will be needed for planetary surface bases. Development of high temperature, high efficiency...

  10. Effect of magnetic dipolar interactions on nanoparticle heating efficiency: Implications for cancer hyperthermia (United States)

    Branquinho, Luis C.; Carrião, Marcus S.; Costa, Anderson S.; Zufelato, Nicholas; Sousa, Marcelo H.; Miotto, Ronei; Ivkov, Robert; Bakuzis, Andris F.


    Nanostructured magnetic systems have many applications, including potential use in cancer therapy deriving from their ability to heat in alternating magnetic fields. In this work we explore the influence of particle chain formation on the normalized heating properties, or specific loss power (SLP) of both low- (spherical) and high- (parallelepiped) anisotropy ferrite-based magnetic fluids. Analysis of ferromagnetic resonance (FMR) data shows that high particle concentrations correlate with increasing chain length producing decreasing SLP. Monte Carlo simulations corroborate the FMR results. We propose a theoretical model describing dipole interactions valid for the linear response regime to explain the observed trends. This model predicts optimum particle sizes for hyperthermia to about 30% smaller than those previously predicted, depending on the nanoparticle parameters and chain size. Also, optimum chain lengths depended on nanoparticle surface-to-surface distance. Our results might have important implications to cancer treatment and could motivate new strategies to optimize magnetic hyperthermia. PMID:24096272

  11. Prototyping Energy Efficient Thermo-Magnetic & Induction Hardening for Heat Treat & Net Shape Forming Applications

    Energy Technology Data Exchange (ETDEWEB)

    Aquil Ahmad


    Within this project, Eaton undertook the task of bringing about significant impact with respect to sustainability. One of the major goals for the Department of Energy is to achieve energy savings with a corresponding reduction in carbon foot print. The use of a coupled induction heat treatment with high magnetic field heat treatment makes possible not only improved performance alloys, but with faster processing times and lower processing energy, as well. With this technology, substitution of lower cost alloys for more exotic alloys became a possibility; microstructure could be tailored for improved magnetic properties or wear resistance or mechanical performance, as needed. A prototype commercial unit has been developed to conduct processing of materials. Testing of this equipment has been conducted and results demonstrate the feasibility for industrial commercialization.

  12. An Efficient Surface Algorithm for Random-Particle Simulation of Vorticity and Heat Transport (United States)

    Smith, P. A.; Stansby, P. K.


    A new surface algorithm has been incorporated into the random-vortex method for the simulation of 2-dimensional laminar flow, in which vortex particles are deleted rather than reflected as they cross a solid surface. This involves a modification to the strength and random walk of newly created vortex particles. Computations of the early stages of symmetric, impulsively started flow around a circular cylinder for a wide range of Reynolds numbers demonstrate that the number of vortices required for convergence is substantially reduced. The method has been further extended to accommodate forced convective heat transfer where temperature particles are created at a surface to satisfy the condition of constant surface temperature. Vortex and temperature particles are handled together throughout each time step. For long runs, in which a steady state is reached, comparison is made with some time-averaged experimental heat transfer data for Reynolds numbers up to a few hundred. A Karman vortex street occurs at the higher Reynolds numbers.

  13. High Efficiency Water Heating Technology Development Final Report. Part I, Lab/Field Performance Evaluation and Accelerated Life Testing of a Hybrid Electric Heat Pump Water Heater (HPWH)

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Murphy, Richard W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linkous, Randall Lee [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    DOE has supported efforts for many years with the objective of getting a water heater that uses heat pump technology (aka a heat pump water heater or HPWH) successfully on the residential equipment market. The most recent previous effort (1999-2002) produced a product that performed very well in ORNL-led accelerated durability and field tests. The commercial partner for this effort, Enviromaster International (EMI), introduced the product to the market under the trade name Watter$aver in 2002 but ceased production in 2005 due to low sales. A combination of high sales price and lack of any significant infrastructure for service after the sale were the principal reasons for the failure of this effort. What was needed for market success was a commercial partner with the manufacturing and market distribution capability necessary to allow economies of scale to lead to a viable unit price together with a strong customer service infrastructure. General Electric certainly meets these requirements, and knowing of ORNL s expertise in this area, approached ORNL with the proposal to partner in a CRADA to produce a high efficiency electric water heater. A CRADA with GE was initiated early in Fiscal Year, 2008. GE initially named its product the Hybrid Electric Water Heater (HEWH).


    Energy Technology Data Exchange (ETDEWEB)

    Sironi, Lorenzo, E-mail: [NASA Einstein Postdoctoral Fellow. (United States)


    In the innermost regions of low-luminosity accretion flows, including Sgr A* at the center of our Galaxy, the frequency of Coulomb collisions is so low that the plasma has two temperatures, with the ions substantially hotter than the electrons. This paradigm assumes that Coulomb collisions are the only channel for transferring the ion energy to the electrons. In this work, the second of a series, we assess the efficiency of electron heating by ion velocity-space instabilities in collisionless accretion flows. The instabilities are seeded by the pressure anisotropy induced by magnetic field amplification, coupled to the adiabatic invariance of the particle magnetic moments. Using two-dimensional particle-in-cell (PIC) simulations, we showed in Paper I that if the electron-to-ion temperature ratio is T {sub 0e}/T {sub 0i} ≲ 0.2, the ion cyclotron instability is the dominant mode for ion betas β{sub 0i} ∼ 5-30 (here, β{sub 0i} is the ratio of ion thermal pressure to magnetic pressure), as appropriate for the midplane of low-luminosity accretion flows. In this work, we employ analytical theory and one-dimensional PIC simulations (with the box aligned with the fastest-growing wave vector of the ion cyclotron mode) to fully characterize how the electron heating efficiency during the growth of the ion cyclotron instability depends on the electron-to-proton temperature ratio, the plasma beta, the Alfvén speed, the amplification rate of the mean field (in units of the ion Larmor frequency), and the proton-to-electron mass ratio. Our findings can be incorporated as a physically grounded subgrid model into global fluid simulations of low-luminosity accretion flows, thus helping to assess the validity of the two-temperature assumption.

  15. Proteolysis, fermentation efficiency, and in vitro ruminal digestion of peanut stover ensiled with raw or heated corn. (United States)

    Yang, C-M J


    Peanut stover (PS) is similar to full-bloom alfalfa hay in chemical composition. The objective of this study was to assess the effect of adding raw or heated corn meal to PS at ensiling on silage N components, fermentation acids, and digestion by ruminal microorganisms. The PS was collected after harvesting of peanuts and ensiled immediately without and with addition of raw or heated corn meal (100 g/kg of fresh weight). Corn was added to PS so that the initial mixture would contain adequate dry matter (DM) (approximately 30%) and additional nonfiber carbohydrate to enhance silage fermentation. After 8 wk of silo fermentation, corn-treated silages contained less structural carbohydrates but more non-fiber carbohydrates compared with the untreated control. A shift from hemicellulose to nonfiber carbohydrate use during silage fermentation was evident by corn treatment. Additional corn at ensiling resulted in silage N with less water-soluble N, protein N, nonprotein N, nonprotein nonammonia N (peptides plus amino acids), and ammonia N. Based on changes in soluble nonprotein N before and after ensiling, the amount of proteolysis was approximately 66% for control silage and was nearly 40% lower in response to corn treatment. Adding corn increased silage lactic acid, but both acetic and propionic acids decreased. These changes were reflected in the lower pH and higher fermentation efficiency with corn-treated silages. More DM was digested and greater amounts of volatile fatty acids, except for branched-chain acids, were produced in vitro by ruminal microorganisms with corn-treated silages. In addition, incubations with silage treated with heated corn contained higher concentrations of acetic and propionic acids compared with raw corn. In vitro ammonia accumulation per unit of DM digested was lower for corn treatments than the control, and for heated corn vs. raw corn-treated silage. These results indicate that supplementation of either raw or heated corn on PS at

  16. Potential for improving the energy efficiency of cryogenic air separation unit (ASU) using binary heat recovery cycles

    International Nuclear Information System (INIS)

    Aneke, Mathew; Wang, Meihong


    In this paper, the potential of improving the energy efficiency of a conventional cryogenic air separation unit (ASU) was investigated through modelling and simulation using Aspen Plus ® v 8.1. It is achieved through converting the heat from the compressor effluent to electricity using organic Ranking cycle (ORC). Two different arrangements of combining compressor and waste heat recovery ORC system were compared with the conventional cryogenic ASU which was used as the benchmark. The benchmark is a conventional cryogenic ASU with 3 stages of compression which uses water for intercooling. In the first arrangement the water used as the cooling fluid of the intercooler/after cooler heat exchanger of a conventional cryogenic ASU process was replaced by R134a which also acts as the working fluid for the ORC system (C3WHR) while in the second arrangement, the 3 stages compressor of the conventional process was replaced with a single stage compressor with the same overall pressure ratio as the conventional process and the hot compressor effluent cooled with R134a which also acts as the working fluid of the ORC system (C1WHR). The simulation results based on a cryogenic ASU capable of processing 100 kg/s of atmospheric air at 30  ° C as feedstock show that the specific power consumption for the pure products which was 0.32 kWh/kg, 0.37 kWh/kg and 17.35 kWh/kg for oxygen, nitrogen and argon respectively for the conventional cryogenic ASU process was reduced by the addition of the waste heat recovery ORC system. The C1WHR reduced the specific power consumption by an average of 0.2% across the aforementioned pure products while the C3WHR reduced it by an average of 11%. The net power consumption of the conventional cryogenic ASU which was 21826.19 kW was also found to be reduced by the same percentage. - Highlights: • We model two cryogenic air separation unit with compressor waste heat recovery. • We compare the specific energy consumption of the models. • We

  17. Heating plant retrofit at Saskatchewan Penitentiary reduces emissions and improves efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Dockrill, P.; Faguy, A. [Natural Resources Canada, CANMET Energy Technology Centre, Ottawa, ON (Canada); Bell, L. [Correctional Services Canada, Saskatoon, SK (Canada)


    Upgrading the central heating plant at the Saskatchewan penitentiary, with technical assistance from the CANMET Energy Technology Centre, is discussed. The technical assistance took the form of an equipment survey, which included a life cycle analysis as part of a non-destructive testing program. Two boilers were found to require major rework to extend their life. The decision was made to replace one of the boilers with two smaller ones sized to match the fall, winter and spring heating loads, complete with NOx burners, upgrade the control system, mothball one of the older boilers and leave the other as a standby. As a result of the changes gas consumption per building area was reduced by 17 per cent and the retrofitted heating plant now meets the federal government guidelines for NOx emissions. Successful implementation of the project is considered as good evidence of the value of life cycle cost analysis for considering the various options available and for providing the confidence that the option selected will meet the desired operational, environmental and economic goals. 1 ref., 1 appendix.

  18. Pulse Mask Controlled HFAC Resonant Converter for high efficiency Industrial Induction Heating with less harmonic distortion

    Directory of Open Access Journals (Sweden)

    Nagarajan Booma


    Full Text Available This paper discusses about the fixed frequency pulse mask control based high frequency AC conversion circuit for industrial induction heating applications. Conventionally, for induction heating load, the output power control is achieved using the pulse with modulation based converters. The conventional converters do not guarantee the zero voltage switching condition required for the minimization of the switching losses. In this paper, pulse mask control scheme for the power control of induction heating load is proposed. This power control strategy allows the inverter to operate closer to the resonant frequency, to obtain zero voltage switching condition. The proposed high frequency AC power conversion circuit has lesser total harmonic distortion in the supply side. Modeling of the IH load, design of conversion circuit and principle of the control scheme and its implementation using low cost PIC controller are briefly discussed. Simulation results obtained using the Matlab environment are presented to illustrate the effectiveness of the pulse mask scheme. The obtained results indicate the reduction in losses, improvement in the output power and lesser harmonic distortion in the supply side by the proposed converter. The hardware results are in good agreement with the simulation results.

  19. The wire array Z-pinch: an efficient x-ray source for ICF and a new ion heating mechanism (United States)

    Haines, M. G.


    The Z-pinch provides an efficient x-ray source for driving a hohlraum for inertial confinement fusion. The basic physics of wire-array implosions is reviewed. It can be understood in several sequential stages. Firstly, the wires heat and form a surrounding vapour which ionizes, causing the current to transfer to this lower resistance. The J×B global force leads to ejection of this plasma towards the axis to form a precursor plasma. The wire cores continue to ablate due to the heat flux from the Joule-heated nearby plasma. The cooling of this plasma by the wire-cores leads to a low magnetic Reynolds number so that the precursor plasma carries little or no current. When gaps appear in the liquid/vapour cores the plasma temperature and Reynolds number rise and this plasma accelerates in towards the axis carrying the current. This is the main implosion, and it sweeps up earlier ablated plasma, which acts to reduce Rayleigh-Taylor growth. At stagnation, the ion kinetic energy is thermalized and equipartition heats the electrons, which then radiate in a 5 ns pulse. In some conditions the energy radiated by soft x-rays exceeds the ion kinetic energy by a factor of 3 or 4. A theory has been developed to explain this in which fine-scale, fast growing m= 0 MHD instabilities grow to saturation, viscous dissipation of which leads to ion heating, followed by equipartition. World record ion temperatures of 2-3 billion Kelvin were predicted, and measured at Sandia National Laboratory. Lastly, progress in capsule implosions and in application to inertial fusion energy is reported.

  20. Heat management methodology for enhanced global efficiency in hybrid electric vehicles

    Directory of Open Access Journals (Sweden)

    F. Claude


    Full Text Available The transportation impact on pollution and global climate change, has forced the automotive sector to search for more ecological solutions. Owing to the different properties of Fuel Cell (FC, real potential for reducing vehicles’ emissions has been witnessed. The optimization of FC integration within Electric Vehicles (EVs is one of the original solutions. This paper presents an innovating solution of multi-stack Fuel Cell Electrical Vehicle (FCEV in terms of efficiency, durability and ecological impact on environment. The main objective is to illustrate the interest of using the multi-stack FC system on the global autonomy, cycling, and efficiency enhancement, besides optimizing its operation performance.

  1. Fuel-efficiency of hydrogen and heat storage technologies for integration of fluctuating renewable energy sources

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad; Lund, Henrik


    This paper presents the methodology and results of analysing the use of different energy storage technologies in the task of integration of fluctuating renewable energy sources (RES) into the electricity supply. The analysis is done on the complete electricity system including renewable energy...... to relocate electricity production directly from the sources, while heat storage devices can be used to relocate the electricity production from CHP plants and hereby improve the ability to integrate RES. The analyses are done by advanced computer modelling and the results are given as diagrams showing...

  2. Modeling of dust emission for a crusted surface (United States)

    Ghodsi Zadeh, Z.; Klose, M.; DuBois, D. W.


    Dust storms are frequent phenomena in the southwestern United Sates. Dust source areas in the region are often (partly) crusted. A critical prerequisite in dust aerosol modeling is an accurate representation of dust emission. While several dust emission schemes have been developed over the last decades, their applicability for crusted surfaces is not well tested. In this study, we use and test the applicability of the dust emission scheme of Shao (2004) (S04), which estimates dust emission based on the soil volume removed by saltation particle impacts, to model dust emission from a crusted surface in New Mexico, USA, for three dust events in spring 2016. Detailed field data are available for these events which are used as scheme input (surface crust and vegetation fraction, friction velocity, minimally- and fully-dispersed particle-size distributions) and for evaluation (saltation flux and dust emission flux). Results show that the saltation flux modeled with the scheme of White (1979) was overestimated by three orders of magnitude. This is expected as the supply of particles available for saltation is limited at the site. As our focus is on dust emission, a constant scaling factor was applied to match modeled and observed saltation fluxes. Parameters that describe the efficiency of saltator impacts to emit dust and the degree of dispersion during erosion need to be adapted in the S04 scheme to represent the soil surface setting at the study site. Our results show that changing those parameters has little effect on the modeled dust emission and dust emission is generally underestimated when PSDs of the top 1 cm soil layer are used as it is common. The reason for this is that the crust at the site is relatively thin and the soil overall sandy, which results in only a small difference between the two PSDs. If, however, the minimally- and fully-dispersed PSDs are replaced with the PSDs of, respectively, loose erodible material and crust, then the difference increases

  3. Prediction of mean skin temperature for use as a heat strain scale by introducing an equation for sweating efficiency (United States)

    Kubota, H.; Kuwabara, K.; Hamada, Y.


    The present paper made the heat balance equation (HBE) for nude or minimally clad subjects a linear function of mean skin temperature ( t sk) by applying new equations for sweating efficiency ( η sw) and thermoregulatory sweat rate ( S wR). As the solution of the HBE, the equation predicting t sk was derived and used for a heat strain scale of subjects. The η sw was proportional to the reciprocal of S w/ E max ( S w, sweat rate; E max maximum evaporative capacity) and the S wR was proportional to t sk with a parameter of the sweating capacity of the subject. The errors of predicted t sk from observations due to the approximation of η sw were examined based on experimental data conducted on eight young male subjects. The value of errors of t sk was -0.10 ± 0.42 °C (mean ± sample standard deviation (SSD)). We aim to apply the predicted t sk of a subject at a level of sweating capacity as a heat strain scale of a function of four environmental factors (dry- and wet-bulb temperatures, radiation, and air velocity) and three human factors (metabolic rate, sweating capacity, and clothing (≤0.2clo)).


    The removal of organic compounds from water by pervaporation is highly energy efficient when the separation factor offered by the pervaporation process is high. In cases where the separation factor is relatively small, consequential amounts of water permeate the membrane per uni...

  5. Efficiencies of subcritical and transcritical CO2 inverse cycles with and without an internal heat exchanger

    International Nuclear Information System (INIS)

    Zhang, F.Z.; Jiang, P.X.; Lin, Y.S.; Zhang, Y.W.


    An internal heat exchanger (IHX) is often used to improve the coefficient of performance (COP) of CO 2 inverse cycles. This paper presents a detailed analysis of the IHX's effect in CO 2 inverse cycles and finds suitable operating conditions for the IHX from a thermodynamic performance point of view. The results indicate that the COP is slightly reduced by an IHX in a CO 2 subcritical inverse cycle, so an IHX is not justified. However, for transcritical CO 2 inverse cycles, the compressor discharge pressures and CO 2 gas cooler outlet temperatures both have significant impacts on system performance. The analysis results for transcritical CO 2 inverse cycles show that a transition discharge pressure and a transition CO 2 gas cooler outlet temperature are objective existence above which the IHX improves the cycle performance. - Research highlights: → Find suitable operating conditions for the IHX. → Above transition CO2 gas cooler outlet temperature IHX improves cycle performance. → The IHX is not very useful for optimized space heating and refrigerating cycles.

  6. On the Evaluation of Solar Greenhouse Efficiency in Building Simulation during the Heating Period

    Directory of Open Access Journals (Sweden)

    Francesco Asdrubali


    Full Text Available Among solar passive systems integrated in buildings, sunspaces or solar greenhouses represent a very interesting solution. A sunspace is a closed, southbound volume, constituted by transparent surfaces, adjacent to a building, which reduces winter energy demand thanks to the use of solar gains. The effect of a typical solar greenhouse on the energy balance of a building was evaluated during the heating period with two stationary procedures (Method 5000 and EN ISO 13790 and with a dynamic tool (TRNSYS. After the analysis of the greenhouse alone, the behavior of an entire house was simulated; a flat equipped with a sunspace, recently built thanks to public contributions provided by the Umbria Region in Italy to widespread bio-climatic architecture, was used as case-study. Simulations were carried out for the examined flat, both with a steady-state tool and with a dynamic one; the contribution of the sunspace was estimated thanks to the various methods previously mentioned. Finally, the simulated data were satisfactorily compared with the real energy consumptions (natural gas for heating of the flat; the sunspace allows a reduction of winter energy demand of the flat of about 20%.

  7. TRIGENERATION - A highly energy efficient source for heating, domestic hot water preparation, electricity and air cooling systems for tertiary sector

    International Nuclear Information System (INIS)

    Barbuta, Mariana; Ghitulescu, Mircea; Nicolau, Irina; Athanasovici, Cristian; Constantin, Cristinel; Ivan, Robert


    The general concerns relating to sustainable energy development have led to the implementation of certain solutions at the international level that have increased both energy generation and energy consuming processes efficiency. In our country the first steps in this direction have been carried out by the private companies that, after having analyzed the income increase and costs diminishing, have come to the conclusion that a reliable way to save money would be the rational use of the energy resources for utilities. A favorable consequence was the synergetic effect of the measures meant to increase energy efficiency for the energy generation and consumption processes that are also accompanied by benefit effects on the environmental impact by reduction CO 2 emissions. One of the solutions making the utmost of primary energy is the combined heat and power production (co-generation) that has significantly developed in our country within the energy sector as a whole. Co-generation may be considered environmentally friendly because it saves fuel on the one hand and, technologically, generates less emissions as compared to the separate generation of heat and power, on the other hand. The most favorable applications of co-generation at a medium and small scale are in the tertiary sector (hotels, hospitals, and office buildings) where heat consumption is usually high enough and is accompanied by relatively constant electricity consumption. By corroborating the above mentioned facts relating to local cogeneration installation utilization with those relating to the increased need for cooling in the tertiary buildings, a concept named 'TRI-GENERATION' in specialized literature has occurred, representing, in fact, utilization of cogeneration installations for supplying energy to the electricity, heat and cold consumer. Thus, the cogeneration installation utilization time will be practically prolonged over the entire duration of a year a fact that has extremely favorable

  8. Numerical investigation of the efficiency of emission reduction and heat extraction in a sedimentary geothermal reservoir: a case study of the Daming geothermal field in China. (United States)

    Guo, Xuyang; Song, Hongqing; Killough, John; Du, Li; Sun, Pengguang


    The utilization of geothermal energy is clean and has great potential worldwide, and it is important to utilize geothermal energy in a sustainable manner. Mathematical modeling studies of geothermal reservoirs are important as they evaluate and quantify the complex multi-physical effects in geothermal reservoirs. However, previous modeling efforts lack the study focusing on the emission reduction efficiency and the deformation at geothermal wellbores caused by geothermal water extraction/circulation. Emission efficiency is rather relevant in geothermal projects introduced in areas characterized by elevated air pollution where the utilization of geothermal energy is as an alternative to burning fossil fuels. Deformation at geothermal wellbores is also relevant as significant deformation caused by water extraction can lead to geothermal wellbore instability and can consequently decrease the effectiveness of the heat extraction process in geothermal wells. In this study, the efficiency of emission reduction and heat extraction in a sedimentary geothermal reservoir in Daming County, China, are numerically investigated based on a coupled multi-physical model. Relationships between the efficiency of emission reduction and heat extraction, deformation at geothermal well locations, and geothermal field parameters including well spacing, heat production rate, re-injection temperature, rock stiffness, and geothermal well placement patterns are analyzed. Results show that, although large heat production rates and low re-injection temperatures can lead to decreased heat production in the last 8 years of heat extraction, they still improve the overall heat production capacity and emission reduction capacity. Also, the emission reduction capacity is positively correlated with the heat production capacity. Deformation at geothermal wellbore locations is alleviated by smaller well spacing, lower heat production rates, and smaller numbers of injectors in the well pattern, and by

  9. A highly efficient six-stroke internal combustion engine cycle with water injection for in-cylinder exhaust heat recovery

    International Nuclear Information System (INIS)

    Conklin, James C.; Szybist, James P.


    A concept adding two strokes to the Otto or Diesel engine cycle to increase fuel efficiency is presented here. It can be thought of as a four-stroke Otto or Diesel cycle followed by a two-stroke heat recovery steam cycle. A partial exhaust event coupled with water injection adds an additional power stroke. Waste heat from two sources is effectively converted into usable work: engine coolant and exhaust gas. An ideal thermodynamics model of the exhaust gas compression, water injection and expansion was used to investigate this modification. By changing the exhaust valve closing timing during the exhaust stroke, the optimum amount of exhaust can be recompressed, maximizing the net mean effective pressure of the steam expansion stroke (MEP steam ). The valve closing timing for maximum MEP steam is limited by either 1 bar or the dew point temperature of the expansion gas/moisture mixture when the exhaust valve opens. The range of MEP steam calculated for the geometry of a conventional gasoline engine and is from 0.75 to 2.5 bars. Typical combustion mean effective pressures (MEP combustion ) of naturally aspirated gasoline engines are up to 10 bar, thus this concept has the potential to significantly increase the engine efficiency and fuel economy.

  10. Geoelectromagnetic investigation of the earth’s crust and mantle

    CERN Document Server

    Rokityansky, Igor I


    Electrical conductivity is a parameter which characterizes composition and physical state of the Earth's interior. Studies of the state equations of solids at high temperature and pressure indicate that there is a close relation be­ tween the electrical conductivity of rocks and temperature. Therefore, measurements of deep conductivity can provide knowledge of the present state and temperature of the Earth's crust and upper mantle matter. Infor­ mation about the temperature of the Earth's interior in the remote past is derived from heat flow data. Experimental investigation of water-containing rocks has revealed a pronounced increase of electrical conductivity in the temperature range D from 500 to 700 DC which may be attributed to the beginning of fractional melting. Hence, anomalies of electrical conductivity may be helpful in identitying zones of melting and dehydration. The studies of these zones are perspective in the scientific research of the mobile areas of the Earth's crust and upper mantle where t...

  11. Reliable, Economic, Efficient CO2 Heat Pump Water Heater for North America

    Energy Technology Data Exchange (ETDEWEB)

    Radcliff, Thomas D; Sienel, Tobias; Huff, Hans-Joachim; Thompson, Adrian; Sadegh, Payman; Olsommer, Benoit; Park, Young


    Adoption of heat pump water heating technology for commercial hot water could save up to 0.4 quads of energy and 5 million metric tons of CO2 production annually in North America, but industry perception is that this technology does not offer adequate performance or reliability and comes at too high of a cost. Development and demonstration of a CO2 heat pump water heater is proposed to reduce these barriers to adoption. Three major themes are addressed: market analysis to understand barriers to adoption, use of advanced reliability models to design optimum qualification test plans, and field testing of two phases of water heater prototypes. Market experts claim that beyond good performance, market adoption requires 'drop and forget' system reliability and a six month payback of first costs. Performance, reliability and cost targets are determined and reliability models are developed to evaluate the minimum testing required to meet reliability targets. Three phase 1 prototypes are designed and installed in the field. Based on results from these trials a product specification is developed and a second phase of five field trial units are built and installed. These eight units accumulate 11 unit-years of service including 15,650 hours and 25,242 cycles of compressor operation. Performance targets can be met. An availability of 60% is achieved and the capability to achieve >90% is demonstrated, but overall reliability is below target, with an average of 3.6 failures/unit-year on the phase 2 demonstration. Most reliability issues are shown to be common to new HVAC products, giving high confidence in mature product reliability, but the need for further work to minimize leaks and ensure reliability of the electronic expansion valve is clear. First cost is projected to be above target, leading to an expectation of 8-24 month payback when substituted for an electric water heater. Despite not meeting all targets, arguments are made that an industry leader could

  12. Hydrothermal activity and the evolution of the seismic properties of upper oceanic crust (United States)

    Grevemeyer, Ingo; Kaul, Norbert; Villinger, Heinrich; Weigel, Wilfried


    In order to investigate the impact of off-axis hydrothermal circulation on changes of the seismic properties of upper oceanic crust (layer 2A), we performed an extensive geophysical survey on the eastern flank of the East Pacific Rise at 14°S. Seismic refraction and heat flow data were obtained along a 720-km-long and 25 to 40-km wide corridor, covering thinly sedimented seafloor created since 8.5 Ma. The seismic data yield a seismic velocity of ˜2.9 km/s at the top of 0.5-m.y.-old basement rocks. Within about 8 m.y. the velocity increases gradually to a value of mature oceanic crust (˜4.3 km/s). Heat flow data, derived from 43 in situ thermal conductivity and 86 geothermal gradient measurements, suggest that an open hydrothermal circulation system persists for at least 6-7 m.y. In crust older than 7 Ma, regional heat flow is close to values predicted by plate cooling models, suggesting that hydrothermal circulation is going to cease. Considering published dating of alteration minerals, it appears that the permeability of uppermost oceanic crust has decreased to values insufficient to promote a vigorous hydrothermal circulation within 10-15 m.y. This idea may explain why seismic velocities in the Pacific ocean have not changed significantly in igneous crust older than 8-10 Ma. In regions where juvenile and consistently hot crust is buried rapidly by sediments the evolution of the seismic properties is quite different; velocities increase rapidly and reach values of mature oceanic crust within 1-2 m.y. We therefore favor a model where basement temperature is governing the evolution of the seismic properties of upper oceanic crust [Stephen and Harding, 1983; Rohr, 1994].

  13. New evidence for efficient collisionless heating of electrons at the reverse shock of a young supernova remnant

    International Nuclear Information System (INIS)

    Yamaguchi, Hiroya; Petre, Robert; Eriksen, Kristoffer A.; Badenes, Carles; Hughes, John P.; Brickhouse, Nancy S.; Foster, Adam R.; Patnaude, Daniel J.; Slane, Patrick O.; Smith, Randall K.


    Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect Kβ (3p → 1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe Kα (2p → 1s) emission dominated by a relatively highly ionized component. Comparisons with our hydrodynamical simulations imply instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe Kα morphology from the Chandra observations. Since strong Fe Kβ fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.

  14. New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant (United States)

    Yamaguchi, Hiroya; Eriksen, Kristoffer A.; Badenes, Carles; Hughes, John P.; Brickhouse, Nancy S.; Foster, Adam R.; Patnaude, Daniel J.; Petre, Robert; Slane, Patrick O.; Smith, Randall K.


    Although collisionless shocks are ubiquitous in astrophysics, certain key aspects of them are not well understood. In particular, the process known as collisionless electron heating, whereby electrons are rapidly energized at the shock front, is one of the main open issues in shock physics. Here, we present the first clear evidence for efficient collisionless electron heating at the reverse shock of Tycho's supernova remnant (SNR), revealed by Fe K diagnostics using high-quality X-ray data obtained by the Suzaku satellite. We detect K beta (3p yields 1s) fluorescence emission from low-ionization Fe ejecta excited by energetic thermal electrons at the reverse shock front, which peaks at a smaller radius than Fe K alpha (2p yields 1s) emission dominated by a relatively highly ionized component. Comparisons with our hydrodynamical simulations imply instantaneous electron heating to a temperature 1000 times higher than expected from Coulomb collisions alone. The unique environment of the reverse shock, which is propagating with a high Mach number into rarefied ejecta with a low magnetic field strength, puts strong constraints on the physical mechanism responsible for this heating and favors a cross-shock potential created by charge deflection at the shock front. Our sensitive observation also reveals that the reverse shock radius of this SNR is about 10% smaller than the previous measurement using the Fe K alpha morphology from the Chandra observations. Since strong Fe K beta fluorescence is expected only from low-ionization plasma where Fe ions still have many 3p electrons, this feature is key to diagnosing the plasma state and distribution of the immediate postshock ejecta in a young SNR.

  15. Nano materials for efficiently lowering the freezing point of heat transfer nanofluids (United States)

    Hong, Haiping; Roy, Walter


    In this paper, we report, for the first time, the effect of the lowered freezing point in a 50% water / 50% antifreeze coolant (PAC) or 50% water / 50% ethylene glycol (EG) solution by the addition of carbon nanotubes and other particles. The experimental results indicated that the nano materials are much more efficient (hundreds fold) in lowering the freezing point than the regular ionic materials (e.g. NaCl). The possible explanation for this interesting phenomenon is the colligative property of fluid and relative small size of nano material. It is quite certain that the carbon nanotubes and metal oxide nano particles could be a wonderful candidate for the nano coolant application because they could not only increase the thermal conductivity, but also efficiently lower the freezing point of traditional coolants.

  16. Intelligent Heat System – high energy efficient wood stoves with low emissions

    DEFF Research Database (Denmark)

    Illerup, Jytte Boll; Nickelsen, Joachim; Hansen, Brian Brun


    This development and demonstration project conducted by HWAM A/S and DTU Chemical Engineering has contributed to the development of an automatically controlled wood stove (HWAM IHS), which is on the market today. The new digital control system ensures optimal combustion conditions by keeping...... optimal temperatures and overall oxygen concentrations in the combustion chamber throughout a complete wood log combustion cycle. This improved performance has been verified by field tests in private homes where measurements showed significant reduced emissions and higher efficiency for the IHS stoves....... Emission measurements at the research wood stove set-up at DTU Chemical Engineering showed generally low emissions of particles, well below current standards, and high energy efficiency. The highest emissions of CO, VOC and PM were seen in the ignition phase while only a small particle peak was observed...

  17. Investigating effect and efficiency of short term heat stress applied in food stuff decontamination

    DEFF Research Database (Denmark)

    Andersen, Ann Zahle; Bagatolli, Luis; Kallipolitis, Birgitte H.

    to the very short treatment times employed (1-2 seconds), we hypothesize that surviving microorganisms may not perceive the applied stress as heat shock. We wish to identify the nature of the damage imposed on bacteria subjected to this type of treatment and investigate the bacterial stress recovery responses...... of surviving organisms. In addition the nature of the changes induced in the foodstuff model is investigated in order to reveal possible influence on microbial growth subsequent to treatment. Methods. Because of their relevance in food industry, we employ Listeria and Salmonella as model bacteria and chicken......Background. Foodborne pathogenic bacteria such as Listeria, Salmonella and Campylobacter represent an increasing health risk in foodstuffs as shelf life is increased and preparation temperatures and time are decreased. SonoSteam® is a thermal treatment, in which the effect of hot steam (> 90°C...

  18. Procedures for Efficient and Economic Recovery of Heat for Reuse in Batch Processes for Cleaning

    DEFF Research Database (Denmark)

    Qvale, Einar Bjørn


    The expenditure of primary energy can be reduced and the economics of process plants in the food industry can be improved by intelligent application of Process Integration (PI). Since a greater part of the products in the food industry is processed in batches, the use of Thermal- Energy Storage...... are often encountered in the food industry. However, the extent to which PI is utilized is much smaller than the number of potential applications. The present paper will address this topic, give some reasons for the underuse of PI, and indicate some principles, methods, and directions that, when applied......, could increase the use and usefulness of PI by incorporating TES, thus fulfilling PI’s promises of improved operation, reduced energy consumption, reduced environmental impact, and improved economics. The application of these procedures is illustrated through the description of two cases. Keywords: Heat...

  19. Models of a partially hydrated Titan interior with clathrate crust (United States)

    Lunine, J. I.; Castillo-Rogez, J.


    We present an updated model of the interior evolution of Titan over time, assuming the silicate core was hydrated early in Titan's history and is dehydrating over time. The original model presented in Castillo-Rogez and Lunine (2010) was motivated by a Cassini-derived moment of inertia (Iess et al., 2010) for Titan too large to be accommodated by classical fully differentiated models in which an anhydrous silicate core was overlain by a water ice (with possible perched ocean) mantle. Our model consisted of a silicate core still in the process of dehydrating today, a situation made possible by the leaching of radiogenic potassium from the silicates into the liquid water ocean. The crust of Titan was assumed to be pure water ice I. The model was consistent with the moment of inertia of Titan, but neglected the presence of large amounts of methane in the upper crust invoked to explain methane's persistence at present and through geologic time (Tobie et al. 2006). We have updated our model with such a feature. We have also improved our modeling with a better physical model for the dehydration of antigorite and other hydrated minerals. In particular our modeling now simulates heat advection resulting from water circulation (e.g., Seipold and Schilling 2003), rather than the purely conductive heat transfer regime assumed in the first version of our model. The modeling proceeds as in Castillo-Rogez and Lunine (2010), with the thermal conductivity of the methane clathrate crust rather than that of ice I. The former is several times lower than that of the latter, and the two have rather different temperature dependences (English and Tse, 2009). The crust turns out to have essentially no bearing on the temperature of the silicate core and hence the timing of dehydration, but it profoundly affects the thickness of the high-pressure ice layer beneath the ocean. Indeed, with the insulating methane clathrate crust, there must be a liquid water ocean beneath the methane clathrate

  20. Keeping warm? Self-reported housing and home energy efficiency factors impacting on older people heating homes in North Wales

    International Nuclear Information System (INIS)

    Burholt, Vanessa; Windle, Gill


    This paper examines a representative sample (N=421) of older people (aged 70+) living in rural North Wales with regard to relationships between fuel poverty, feeling cold in one's home and a range of self-reported housing and home energy efficiency items. In the Welsh context, the combination of poor housing stock and low-level income is likely to increase the chance of older people experiencing fuel poverty, therefore the analyses are relevant to both energy and social policy. The paper hypothesises that: (i) People in 'fuel poor' homes are: low-income households; living in older houses; lacking home energy efficiency measures; (ii) not all people facing difficulties heating their home (i.e. wearing extra clothing to keep warm during cold spells) are identified as 'fuel poor', but there will be an association between taking extra measures to keep warm and low income; older houses and lacking home energy efficiency factors. The results partially support the hypotheses. An estimation is made of the expenditure required to counter the factors associated with fuel poverty and cold homes in the region. The paper concludes with implications for the UK Fuel Poverty Strategy

  1. Influence of Different Temperature Sensors on Measuring Energy Efficiency and Heating-Up Time of Hobs (United States)

    Beges, G.; Drnovsek, J.; Ogorevc, J.; Bojkovski, J.


    Measuring performance, mainly temperature dependence, for electric cooking ranges, hobs, ovens, and grills for household use is essential for producers as low power consumption of appliances represents a powerful selling point and also in terms of ecodesign requirements. It is also important from a consumer perspective, as these appliances are responsible for the significant share of households' electricity bills. The aim of the paper was to highlight and clearly define possible ambiguities and weaknesses of standardized procedures for measuring hob performance. Differences between measurement/test results of testing laboratories are possible due to lack of detailed information in the standard, and it is difficult to obtain technical accessories required in the standard. An energy consumption comparison of three different hobs is presented (standard iron electrical hob, radiant-glass ceramic, and induction hob). Various temperature sensors (different types of thermocouples and a platinum resistance thermometer) and technical accessories (e.g., different cookware) were used to research differences or influences on final result of hobs' energy efficiency. Results show that temperature measurements with different sensors have an influence on the time difference in critical points for determination of hob energy efficiency.

  2. CHP: Combined Heat and Power: a vision of energy efficiency; Cogeracao: uma visao de eficiencia energetica

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Osvaldo A.S.N. de; Abreu, Melissa E. de; Marcal, Roberto L.; Ferreira, Ademilson D.; Ferreira, Patricia E.; Monterio, Glauber J.R.; Silva, Ademir B. [PETROBRAS, Rio de Janeiro, RJ (Brazil)


    The installation of a cogeneration plant has been the subject of discussions on alternatives in the Brazilian energy matrix. Considered viable solution in the not too distant past, 2001, when Brazil was undergoing a process of the economic slowdown, lack of investments in the energy sector, unemployment and reaching the peak of the crisis with the rationing of electricity. The principle of the cogeneration system is designed primarily to meet electrical demand, so there is no surplus production of energy and do not need to buy with the concessionaire, except in cases of the system stops on account of maintenance. However, there is a recovery of waste heat produced in thermodynamic processes for generation of electricity within a model that 'conventional' would be wasted. In this case, the exploitation can be given in the form of steam, hot water and/or cold, for secondary application, or can not be linked to a process. Based on the results of the fieldwork, aims to show that, despite the limitations inherent in the process of cogeneration, is justified economically the installation of this system in relation to the growth of procedures developed in CENPES and its resident effective. (author)

  3. Evaluation of the thermal efficiency and a cost analysis of different types of ground heat exchangers in energy piles

    International Nuclear Information System (INIS)

    Yoon, Seok; Lee, Seung-Rae; Xue, Jianfeng; Zosseder, Kai; Go, Gyu-Hyun; Park, Hyunku


    Highlights: • We performed field TPT with W and coil-type GHEs in energy piles. • We evaluated heat exchange rates from TPT results. • Field TPT results were compared with numerical analysis. • Cost analysis with GSHP design method was conducted for each type of GHEs in energy piles. - Abstract: This paper presents an experimental and numerical study of the results of a thermal performance test using precast high-strength concrete (PHC) energy piles with W and coil-type ground heat exchangers (GHEs). In-situ thermal performance tests (TPTs) were conducted for four days under an intermittent operation condition (8 h on; 16 h off) on W and coil-type PHC energy piles installed in a partially saturated weathered granite soil deposit. In addition, three-dimensional finite element analyses were conducted and the results were compared with the four-day experimental results. The heat exchange rates were also predicted for three months using the numerical analysis. The heat exchange rate of the coil-type GHE showed 10–15% higher efficiency compared to the W-type GHE in the energy pile. However, in considering the cost for the installation of the heat exchanger and cement grouting the additional cost of W-type GHE in energy pile was 200–250% cheaper than coil-type GHE under the condition providing equivalent thermal performance. Furthermore, the required lengths of the W, 3U and coil-type GHEs in the energy piles were calculated based on the design process of Kavanaugh and Rafferty. The additional cost for the W and 3U types of GHEs were also 200–250% lower than that of the coil-type GHE. However, the required number of piles was much less with the coil-type GHE as compared to the W and 3U types of GHEs. They are advantageous in terms of the construction period, and further, selecting the coil-type GHE could be a viable option when there is a limitation in the number of piles in consideration of the scale of the building.

  4. Hybrid pressure retarded osmosis-membrane distillation system for power generation from low-grade heat: thermodynamic analysis and energy efficiency. (United States)

    Lin, Shihong; Yip, Ngai Yin; Cath, Tzahi Y; Osuji, Chinedum O; Elimelech, Menachem


    We present a novel hybrid membrane system that operates as a heat engine capable of utilizing low-grade thermal energy, which is not readily recoverable with existing technologies. The closed-loop system combines membrane distillation (MD), which generates concentrated and pure water streams by thermal separation, and pressure retarded osmosis (PRO), which converts the energy of mixing to electricity by a hydro-turbine. The PRO-MD system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages for heat source temperatures ranging from 40 to 80 °C and working concentrations of 1.0, 2.0, and 4.0 mol/kg NaCl. The factors controlling the energy efficiency of the heat engine were evaluated for both limited and unlimited mass and heat transfer kinetics in the thermal separation stage. In both cases, the relative flow rate between the MD permeate (distillate) and feed streams is identified as an important operation parameter. There is an optimal relative flow rate that maximizes the overall energy efficiency of the PRO-MD system for given working temperatures and concentration. In the case of unlimited mass and heat transfer kinetics, the energy efficiency of the system can be analytically determined based on thermodynamics. Our assessment indicates that the hybrid PRO-MD system can theoretically achieve an energy efficiency of 9.8% (81.6% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and a working solution of 1.0 M NaCl. When mass and heat transfer kinetics are limited, conditions that more closely represent actual operations, the practical energy efficiency will be lower than the theoretically achievable efficiency. In such practical operations, utilizing a higher working concentration will yield greater energy efficiency. Overall, our study demonstrates the theoretical viability of the PRO-MD system and identifies the key factors for performance

  5. Infrared monitoring of power-plant effluents and heat sinks to optimize plant efficiency (United States)

    Wurzbach, Richard N.; Seith, David A.


    Infrared imaging of the discharge canal and intake pond of the Peach Bottom Atomic Power Station was initiated to confirm a plant staff suspicion that high water intake temperatures were being influenced by recirculation of discharge flow. To minimize the angle of incidence to the water surface, the inspection was made from the top of the cooling towers. Although there was no evidence of recirculation from the plant discharge to the intake pond, two unexpected inputs of thermal energy were discovered during the inspection. A faulty sluice gate and a damaged cross-around pipe could be seen to be dumping thermal energy into the intake pond. The result was increased temperatures at the intake which threatened plant operation, decreased plant efficiency, and resulted in fewer megawatts available to sell to customers during the critical summer months.

  6. Helium isotopes in ferromanganese crusts from the central Pacific Ocean (United States)

    Basu, S.; Stuart, F.M.; Klemm, V.; Korschinek, G.; Knie, K.; Hein, J.R.


    Helium isotopes have been measured in samples of two ferromanganese crusts (VA13/2 and CD29-2) from the central Pacific Ocean. With the exception of the deepest part of crust CD29-2 the data can be explained by a mixture of implanted solar- and galactic cosmic ray-produced (GCR) He, in extraterrestrial grains, and radiogenic He in wind-borne continental dust grains. 4He concentrations are invariant and require retention of less than 12% of the in situ He produced since crust formation. Loss has occurred by recoil and diffusion. High 4He in CD29-2 samples older than 42 Ma are correlated with phosphatization and can be explained by retention of up to 12% of the in situ-produced 4He. 3He/4He of VA13/2 samples varies from 18.5 to 1852 Ra due almost entirely to variation in the extraterrestrial He contribution. The highest 3He/4He is comparable to the highest values measured in interplanetary dust particles (IDPs) and micrometeorites (MMs). Helium concentrations are orders of magnitude lower than in oceanic sediments reflecting the low trapping efficiency for in-falling terrestrial and extraterrestrial grains of Fe-Mn crusts. The extraterrestrial 3He concentration of the crusts rules out whole, undegassed 4–40 μm diameter IDPs as the host. Instead it requires that the extraterrestrial He inventory is carried by numerous particles with significantly lower He concentrations, and occasional high concentration GCR-He-bearing particles.

  7. Engineered Osmosis for Energy Efficient Separations: Optimizing Waste Heat Utilization FINAL SCIENTIFIC REPORT DOE F 241.3

    Energy Technology Data Exchange (ETDEWEB)



    The purpose of this study is to design (i) a stripper system where heat is used to strip ammonia (NH{sub 3}) and carbon dioxide (CO{sub 2}) from a diluted draw solution; and (ii) a condensation or absorption system where the stripped NH{sub 3} and CO{sub 2} are captured in condensed water to form a re-concentrated draw solution. This study supports the Industrial Technologies Program of the DOE Office of Energy Efficiency and Renewable Energy and their Industrial Energy Efficiency Grand Challenge award solicitation. Results from this study show that stimulated Oasys draw solutions composed of a complex electrolyte solution associated with the dissolution of NH{sub 3} and CO{sub 2} gas in water can successfully be stripped and fully condensed under standard atmospheric pressure. Stripper bottoms NH{sub 3} concentration can reliably be reduced to < 1 mg/L, even when starting with liquids that have an NH{sub 3} mass fraction exceeding 6% to stimulate diluted draw solution from the forward osmosis membrane component of the process. Concentrated draw solution produced by fully condensing the stripper tops was show to exceed 6 M-C with nitrogen-to-carbon (N:C) molar ratios on the order of two. Reducing the operating pressure of the stripper column serves to reduce the partial vapor pressure of both NH{sub 3} and CO{sub 2} in solution and enables lower temperature operation towards integration of industrial low-grade of waste heat. Effective stripping of solutes was observed with operating pressures as low as 100 mbar (3-inHg). Systems operating at reduced pressure and temperature require additional design considerations to fully condense and absorb these constituents for reuse within the Oasys EO system context. Comparing empirical data with process stimulation models confirmed that several key parameters related to vapor-liquid equilibrium and intrinsic material properties were not accurate. Additional experiments and refinement of material property databases within the

  8. A demonstration of the improved efficiency of the canonical coordinates method using nonlinear combined heat and power economic dispatch problems (United States)

    Chang, Hung-Chieh; Lin, Pei-Chun


    Economic dispatch is the short-term determination of the optimal output from a number of electricity generation facilities to meet the system load while providing power. As such, it represents one of the main optimization problems in the operation of electrical power systems. This article presents techniques to substantially improve the efficiency of the canonical coordinates method (CCM) algorithm when applied to nonlinear combined heat and power economic dispatch (CHPED) problems. The improvement is to eliminate the need to solve a system of nonlinear differential equations, which appears in the line search process in the CCM algorithm. The modified algorithm was tested and the analytical solution was verified using nonlinear CHPED optimization problems, thereby demonstrating the effectiveness of the algorithm. The CCM methods proved numerically stable and, in the case of nonlinear programs, produced solutions with unprecedented accuracy within a reasonable time.

  9. Response of Surface Soil Hydrology to the Micro-Pattern of Bio-Crust in a Dry-Land Loess Environment, China. (United States)

    Wei, Wei; Yu, Yun; Chen, Liding


    The specific bio-species and their spatial patterns play crucial roles in regulating eco-hydrologic process, which is significant for large-scale habitat promotion and vegetation restoration in many dry-land ecosystems. Such effects, however, are not yet fully studied. In this study, 12 micro-plots, each with size of 0.5 m in depth and 1 m in length, were constructed on a gentle grassy hill-slope with a mean gradient of 8° in a semiarid loess hilly area of China. Two major bio-crusts, including mosses and lichens, had been cultivated for two years prior to the field simulation experiments, while physical crusts and non-crusted bare soils were used for comparison. By using rainfall simulation method, four designed micro-patterns (i.e., upper bio-crust and lower bare soil, scattered bio-crust, upper bare soil and lower bio-crust, fully-covered bio-crust) to the soil hydrological response were analyzed. We found that soil surface bio-crusts were more efficient in improving soil structure, water holding capacity and runoff retention particularly at surface 10 cm layers, compared with physical soil crusts and non-crusted bare soils. We re-confirmed that mosses functioned better than lichens, partly due to their higher successional stage and deeper biomass accumulation. Physical crusts were least efficient in water conservation and erosion control, followed by non-crusted bare soils. More importantly, there were marked differences in the efficiency of the different spatial arrangements of bio-crusts in controlling runoff and sediment generation. Fully-covered bio-crust pattern provides the best option for soil loss reduction and runoff retention, while a combination of upper bio-crust and lower bare soil pattern is the least one. These findings are suggested to be significant for surface-cover protection, rainwater infiltration, runoff retention, and erosion control in water-restricted and degraded natural slopes.


    Directory of Open Access Journals (Sweden)

    V. N. Glaznev


    Full Text Available The complex geophysical 3D model of the Earth's crust and the upper mantle is created for the Archaean Karelian Craton and the Late Palaeoproterozoic accretionary Svecofennian Orogen of the southeastern Fennoscandian Shield with the use of methods of complex inversion of geophysical data based on stochastic description of interrelations of physical properties of the medium (density, P-wave velocity, and heat generation. To develop the model, we use results of deep seismic studies, gravity and surficial heat flow data on the studied region. Numerical solutions of 3D problems are obtained in the spherical setting with an allowance for the Earth's surface topography. The geophysical model is correlated with the regional geological data on the surface and results of seismic CMP studies along 4B, FIRE-1 and FIRE-3-3A profiles. Based on results of complex geophysical simulation and geological interpretation of the 3D model, the following conclusions are drawn. (1 The nearly horizontal density layering of the continental crust is superimposed on the previously formed geological structure; rock differentiation by density is decreasing with depth; the density layering is controlled by the recent and near-recent state of the crust, but can be disturbed by the latest deformations. (2 Temperature variations at the Moho are partially determined by local variations of heat generation in the mantle, which, in turn, are related to local features of its origin and transformation. (3 The concept of the lower continental crust being a reflectivity zone and the concept of the lower continental crust being a layer of high density and velocity are not equivalent: the lower crust is the deepest, high-density element of near-horizontal layering, whereas the seismic image of the reflectivity zone is primarily related to transformation of the crust as a result of magmatic under- and intraplating under conditions of extension and mantle-plume activity. (4 At certain

  11. Geological and Mineralogical-technological features chromite ore from nickel-weathering crusts Average Bug

    Directory of Open Access Journals (Sweden)

    Perkov E.S.


    Full Text Available Conditions of occurrence and distribution features of chromites ore bodies in the ultra-basic nickel bearing weathering crusts of Middle Bug Area are considered. Main types of exogenous chromites ores in weathering crusts and beyond of them are identified as well as mineralogical, chemical and grain features of mineralization are given. Obtained data are substantiated in order to apply them while developing the efficient schemes of mining and processing of exogenous chromites ores.

  12. Human Thermal Comfort and Heat Removal Efficiency for Ventilation Variants in Passenger Cars

    Directory of Open Access Journals (Sweden)

    Saboora Khatoon


    Full Text Available The realization of a comfortable thermal environment with low energy consumption and improved ventilation in a car has become the aim of manufacturers in recent decades. Novel ventilation concepts with more flexible cabin usage and layouts are appealing owing to their potential for improving passenger comfort and driving power. In this study, three variant ventilation concepts are investigated and their performance is compared with respect to energy efficiency and human comfort of the driver and passenger in front and a child in the rear compartment. FLUENT 16.0, a commercial three-dimensional (3D software, are used for the simulation. A surface-to-surface radiation model is applied under transient conditions for a car parked in summer conditions with its engine in the running condition. The results for the standard Fanger’s model and modified Fanger’s model are analyzed, discussed, and compared for the driver, passenger, and child. The modified Fanger’s model determines the thermal sensation on the basis of mean arterial pressure.

  13. Energetic retrofitting of industrial heat supply systems. Possibilities of enhancing the efficiency and energy conservation at large combustion engineering plants; Energetische Modernisierung industrieller Waermeversorgungssysteme. Moeglichkeiten der Effizienzsteigerung und der Energieeinsparung an grossen feuerungstechnischen Anlagen

    Energy Technology Data Exchange (ETDEWEB)



    In the contribution under consideration, the Deutsche Energie-Agentur GmbH (Berlin, Federal Republic of Germany) reports on an energetic modernization of industrial heat supply systems. Possibilities of an enhancement of the energetic efficiency and energy conservation at large combustion engineering plants are described. After an introduction to this theme, the author of this contribution provides an overview of the optimization of heat supply systems, and reports on the following aspects: Optimisation of the heat demand; energy efficient heat generation; heat recovery; energy efficient conversion technology and generation technology; associate partners for more energy efficiency in industry and commerce; best practice examples.

  14. Zoning of the Territory of Russia According to the Efficiency of the Use of Low-Grade Ground Heat for Heating

    Directory of Open Access Journals (Sweden)

    Vasilyev G.P.


    Full Text Available This paper reports the results of study on the effectiveness of using low-grade ground heat in heat pump systems under the climatic conditions of Russia. The study was performed using the software package “INSOLAR.GSHP.12”, which simulates the non-stationary thermal conditions of ground source heat pumps (GSHPs over several years of operation. The paper presents the results of the zoning of the territory of Russia according to the effectiveness of using low-grade ground heat in heat pump systems. The zoning was performed with consideration of the decrease of the soil temperatures over several years of heat collection system operation. The soil temperatures expected on the fifth year of operation were considered to be the design temperatures. The described study was performed with the financial support of the Ministry of Education and Science of Russia. Contract ID RFMEFI57914X0026.

  15. Temperature Sensor Feasibility Study of Wireless Sensor Network Applications for Heating Efficiency Maintenance in High-Rise Apartment Buildings

    Directory of Open Access Journals (Sweden)

    Freliha B.


    Full Text Available Cities are responsible for 60%-80% of the world’s energy use and for approximately the same percentage of greenhouse gas emissions. The existing multi-apartment buildings of multifamily housing sector are often energy inefficient, and the heating system does not ensure optimization of heat distribution of individual apartments. Heat distribution, heating system balancing, heat loss detection and calculation, individual heat energy accounting are difficult tasks to accomplish. This article deals with the temperature monitoring system designed to retrieve temperature differences necessary for overall building heat monitoring and individual apartment monitoring. The sensor testing case study process and its measurements are analysed.

  16. Coupling and power transfer efficiency enhancement of modular and array of planar coils using in-plane ring-shaped inner ferrites for inductive heating applications (United States)

    Kilic, V. T.; Unal, E.; Demir, H. V.


    We propose and demonstrate a highly effective method of enhancing coupling and power transfer efficiency in inductive heating systems composed of planar coils. The proposed method is based on locating ring-shaped ferrites in the inner side of the coils in the same plane. Measurement results of simple inductive heating systems constructed with either a single or a pair of conventional circular coils show that, with the in-plane inner ferrites, the total dissipated power of the system is increased by over 65%. Also, with three-dimensional full electromagnetic solutions, it is found that power transfer efficiency of the system is increased up to 92% with the inner ferrite placement. The proposed method is promising to be used for efficiency enhancement in inductive heating applications, especially in all-surface induction hobs.


    Directory of Open Access Journals (Sweden)

    Sit B.M.


    Full Text Available A diagram of the heat pump station (HPS for the central heat supply station of the district heating system, which gets the power from the CHP plant is examined. A block diagram of the control of the system and compressor pressure control system are examined. The description of the control laws of evaporator at the variable heat load of the HPS and control laws of the gas cooler taking into account the goal of achieving the maximum of COP of HPS is shown as well.

  18. Fault zone architecture of the San Jacinto fault zone in Horse Canyon, southern California: A model for focused post-seismic fluid flow and heat transfer in the shallow crust (United States)

    Morton, Nissa; Girty, Gary H.; Rockwell, Thomas K.


    the top of a narrow, ephemeral hydrothermal circulation cell that dissipates heat generated from rupture events at deeper levels (> 4 km).

  19. A thin, dense crust for Mercury (United States)

    Sori, Michael M.


    Crustal thickness is a crucial geophysical parameter in understanding the geology and geochemistry of terrestrial planets. Recent development of mathematical techniques suggests that previous studies based on assumptions of isostasy overestimated crustal thickness on some of the solid bodies of the solar system, leading to a need to revisit those analyses. Here, I apply these techniques to Mercury. Using MESSENGER-derived elemental abundances, I calculate a map of grain density (average 2974 ± 89 kg/m3) which shows that Pratt isostasy is unlikely to be a major compensation mechanism of Mercury's topography. Assuming Airy isostasy, I find the best fit value for Mercury's mean crustal thickness is 26 ± 11 km, 25% lower than the most recently reported and previously thinnest number. Several geological implications follow from this relatively low value for crustal thickness, including showing that the largest impacts very likely excavated mantle material onto Mercury's surface. The new results also show that Mercury and the Moon have a similar proportion of their rocky silicates composing their crusts, and thus Mercury is not uniquely efficient at crustal production amongst terrestrial bodies. Higher resolution topography and gravity data, especially for the southern hemisphere, will be necessary to refine Mercury's crustal parameters further.

  20. Features of the survey of heat consumption in the development of a comprehensive plan for energy efficiency institution of higher education

    Directory of Open Access Journals (Sweden)

    Lagereva E.A.


    Full Text Available The methodology of the survey of heat consumption in the development of a comprehensive plan for energy conserva-tion educational institutions of higher education. The results of field studies of heat consumption one of the educational institutions of the city of Bryansk. The survey was done study of the temperature and humidity and an air regimen of locations, a thermographic survey of the exterior enclosures of buildings, the analysis of the data of heat meters. Built valid temperature charts of the surveyed buildings, obtained by processing the experimental data using the least squares method. Graphs of actual and theoretical costs of TEP-lots daily during the whole heating period. Propose concrete actions, allowing to increase the efficiency of the heating system of the educational institution.

  1. Crust formation and dissolution during corium concrete interaction

    International Nuclear Information System (INIS)

    Carenini, L.; Haquet, J.F.; Journeau, Ch.


    In the hypothetical case of a severe accident, the reactor core could melt and the formed mixture, called corium, could melt through the vessel and interact with the reactor pit concrete. Recent two-dimensional concrete-ablation experiments (CCI and VULCANO VB test series) have shown that the ablation is roughly isotropic for limestone-rich concretes while, for silica-rich concretes, ablation is slower downwards than sideward. Crusts at the pool bottom are assumed to be mechanically more stable than those on the vertical walls. Models for the solidification and the melting of these crusts are proposed. They describe the transient heat and mass transfer in the following multilayered system: solid concrete, molten concrete, corium crust, liquid corium. It appears that molten concrete can play a significant role in dissolving the solidified corium crust. This effect is important for limestone-rich concretes due to the presence of a eutectic in the corium-concrete pseudo-binary phase diagram and to the larger chemical diffusion coefficient in the silica-poor concrete melts. For silica-rich concretes, it has been observed that siliceous aggregates are not molten with the surrounding mortar but have been found entrapped in the solidified pool near its boundaries, during post-test examinations. They can contribute to the solidification of corium, acting as cold sources. A model of the simultaneous gravel melting and corium solidification based on Kerr (1994) works is proposed. Numerical applications to the oxidic-corium concrete interaction tests performed in the VULCANO facility with the two types of concretes and two corium compositions will be presented and discussed to support this analytical approach. (authors)

  2. USArray Imaging of North American Continental Crust (United States)

    Ma, Xiaofei

    The layered structure and bulk composition of continental crust contains important clues about its history of mountain-building, about its magmatic evolution, and about dynamical processes that continue to happen now. Geophysical and geological features such as gravity anomalies, surface topography, lithospheric strength and the deformation that drives the earthquake cycle are all directly related to deep crustal chemistry and the movement of materials through the crust that alter that chemistry. The North American continental crust records billions of years of history of tectonic and dynamical changes. The western U.S. is currently experiencing a diverse array of dynamical processes including modification by the Yellowstone hotspot, shortening and extension related to Pacific coast subduction and transform boundary shear, and plate interior seismicity driven by flow of the lower crust and upper mantle. The midcontinent and eastern U.S. is mostly stable but records a history of ancient continental collision and rifting. EarthScope's USArray seismic deployment has collected massive amounts of data across the entire United States that illuminates the deep continental crust, lithosphere and deeper mantle. This study uses EarthScope data to investigate the thickness and composition of the continental crust, including properties of its upper and lower layers. One-layer and two-layer models of crustal properties exhibit interesting relationships to the history of North American continental formation and recent tectonic activities that promise to significantly improve our understanding of the deep processes that shape the Earth's surface. Model results show that seismic velocity ratios are unusually low in the lower crust under the western U.S. Cordillera. Further modeling of how chemistry affects the seismic velocity ratio at temperatures and pressures found in the lower crust suggests that low seismic velocity ratios occur when water is mixed into the mineral matrix

  3. Efficient destruction of CF4 through in situ generation of alkali metals from heated alkali halide reducing mixtures. (United States)

    Lee, Myung Churl; Choi, Wonyong


    Perfluorocarbons (PFCs) are the most potent green house gases that are very recalcitrant at destruction. An effective way of converting PFCs using hot solid reagents into safe products has been recently introduced. By investigating the thermal reductive destruction of tetrafluoromethane (CF4) we provided new insight and more physicochemical consideration on this novel process. The complete destruction of CF4was successfully achieved by flowing the gas through a heated reagent bed (400-950 degrees C) that contained powder mixtures of alkali halides, CaO, and Si. The silicon acted as a reducing agent of alkali halides for the in-situ production of alkali metals, and the calcium oxide played the role of a halide ion acceptor. The absence of any single component in this ternary mixture drastically reduced the destruction efficiency of CF4. The CF4 destruction efficiencies with the solid reagent containing the alkali halide, MX, increased in the order of Li approximately Na < K < Cs for alkali cations and I < Br < Cl < F for halide anions. This trend agreed with the endothermicity of the alkali metal generation reaction: the higher the endothermicity, the lower the destruction efficiency. Alkali metal generation was indirectly detected by monitoring H2 production from its reaction with water. The production of alkali metals increased with NaF, KF, and CsF in this order. The CsF/CaO/Si system exhibited the complete destruction of CF4 at as low as 600 degrees C. The solid product analysis by X-ray diffraction (XRD) showed the formation of CaF2 and the depletion of Si with black carbon particles formed in the solid reagent residue. No CO/CO2 and toxic HF and SiF4 formation were detected in the exhaust gas.

  4. Drought priming at vegetative growth stage enhances nitrogen-use efficiency under post-anthesis drought and heat stress in wheat

    DEFF Research Database (Denmark)

    Liu, S.; Li, Xiangnan; Larsen, Dorthe Horn


    reached ca. −0.9 MPa) at the 5th-leaf stage for 11 days, and leaf water relations and gas exchange rates, grain yield and yield components, and agronomic nitrogen-use efficiency (ANUE) of the primed and non-primed plants under post-anthesis drought and heat stress were investigated. Compared with the non......-primed plants, the drought-primed plants possessed higher leaf water potential and chlorophyll content, and consequently a higher photosynthetic rate during post-anthesis drought and heat stress. Drought priming also resulted in higher grain yield and ANUE in wheat under post-anthesis drought and heat stress...

  5. Microphytic crusts: 'topsoil' of the desert (United States)

    Belnap, Jayne


    Deserts throughout the world are the home of microphytic, or cryptogamic, crusts. These crusts are dominated by cyanobacteria, previously called blue-green algae, and also include lichens, mosses, green algae, microfungi and bacteria. They are critical components of desert ecosystems, significantly modifying the surfaces on which they occur. In the cold deserts of the Colorado Plateau (including parts of Utah, Arizona, Colorado, and New Mexico), these crusts are extraordinarily well-developed, and may represent 70-80% of the living ground cover.

  6. Fluid-cooled heat sink with improved fin areas and efficiencies for use in cooling various devices (United States)

    Bharathan, Desikan; Bennion, Kevin; Kelly, Kenneth; Narumanchi, Sreekant


    The disclosure provides a fluid-cooled heat sink having a heat transfer base and a plurality of heat transfer fins in thermal communication with the heat transfer base, where the heat transfer base and the heat transfer fins form a central fluid channel through which a forced or free cooling fluid may flow. The heat transfer pins are arranged around the central fluid channel with a flow space provided between adjacent pins, allowing for some portion of the central fluid channel flow to divert through the flow space. The arrangement reduces the pressure drop of the flow through the fins, optimizes average heat transfer coefficients, reduces contact and fin-pin resistances, and reduces the physical footprint of the heat sink in an operating environment.

  7. Energy and Economic Efficiency of Gas Turbine Units and Heat Pumps in Power-supply Systems in the Arctic Regions of Russia

    Directory of Open Access Journals (Sweden)

    Suvorov D.M.


    Full Text Available Currently, in publications, there is some controversy about the efficiency of various power-supply systems operating in extreme climatic conditions. The need to dispel this controversy explains this study's relevance. The purpose of this study is to evaluate the feasibility of the use of cogeneration gas turbine and microturbine units as the heat-and-power source for a camp-like residential facility in the Arctic regions of Russia. A boiler plant and a heat pump system are analyzed as heat sources for the afore-mentioned camp. The authors used their own mathematical models of the units to do the study. The estimates were based on the annual facility-specific power and heat consumption data, additionally climatic conditions and fuel kind (natural gas were taken into consideration. The study resulted in defining the plants' limits of equal fuel consumption, depending on the substituted power output efficiency and the power/heat production cost to the price of gas correlation. Another result was the evaluation of the power efficiency (by the natural gas consumption and economic feasibility, as well as the payback term. We concluded that in case the natural gas was the only fuel available the ground source vapor-compressing heat pump systems were power-wise and economically unsound, provided they were operated under environmental conditions typical for the Russian North and according to the region-specific heat-supply schedule. The outcome of this study can be used when planning/designing the power-supply facilities in extreme climatic conditions, as well as in evaluating/estimating the power-supply systems' efficiency.

  8. Buoyancy and Dissolution of the Floating Crust Layer in Tank 241-SY-101 During Transfer and Back-Dilution

    International Nuclear Information System (INIS)

    Stewart, C.W.; Sukamto, J.H.; Cuta, J.M.; Rassat, S.D.


    To remediate gas retention in the floating crust layer and the potential for buoyant displacement gas releases from below the crust, waste will be transferred out of Hanford Tank 241-SY-101 (SY-101) in the fall of 1999 and back-diluted with water in several steps of about 100,000 gallons each. To evaluate the effects of back-dilution on the crust a static buoyancy model is derived that predicts crust and liquid surface elevations as a function of mixing efficiency and volume of water added during transfer and back-dilution. Experimental results are presented that demonstrate the basic physics involved and verify the operation of the models. A dissolution model is also developed to evaluate the effects of dissolution of solids on crust flotation. The model includes dissolution of solids suspended in the slurry as well as in the crust layers. The inventory and location of insoluble solids after dissolution of the soluble fraction are also tracked. The buoyancy model is applied to predict the crust behavior for the first back-dilution step in SY-101. Specific concerns addressed include conditions that could cause the crust to sink and back-dilution requirements that keep the base of the crust well above the mixer pump inlet

  9. Power and Efficiency Analysis of a Solar Central Receiver Combined Cycle Plant with a Small Particle Heat Exchanger Receiver (United States)

    Virgen, Matthew Miguel

    Two significant goals in solar plant operation are lower cost and higher efficiencies. To achieve those goals, a combined cycle gas turbine (CCGT) system, which uses the hot gas turbine exhaust to produce superheated steam for a bottoming Rankine cycle by way of a heat recovery steam generator (HRSG), is investigated in this work. Building off of a previous gas turbine model created at the Combustion and Solar Energy Laboratory at SDSU, here are added the HRSG and steam turbine model, which had to handle significant change in the mass flow and temperature of air exiting the gas turbine due to varying solar input. A wide range of cases were run to explore options for maximizing both power and efficiency from the proposed CSP CCGT plant. Variable guide vanes (VGVs) were found in the earlier model to be an effective tool in providing operational flexibility to address the variable nature of solar input. Combined cycle efficiencies in the range of 50% were found to result from this plant configuration. However, a combustor inlet temperature (CIT) limit leads to two distinct Modes of operation, with a sharp drop in both plant efficiency and power occurring when the air flow through the receiver exceeded the CIT limit. This drawback can be partially addressed through strategic use of the VGVs. Since system response is fully established for the relevant range of solar input and variable guide vane angles, the System Advisor Model (SAM) from NREL can be used to find what the actual expected solar input would be over the course of the day, and plan accordingly. While the SAM software is not yet equipped to model a Brayton cycle cavity receiver, appropriate approximations were made in order to produce a suitable heliostat field to fit this system. Since the SPHER uses carbon nano-particles as the solar absorbers, questions of particle longevity and how the particles might affect the flame behavior in the combustor were addressed using the chemical kinetics software Chemkin


    Directory of Open Access Journals (Sweden)

    O. Ostapenko


    Full Text Available The increasing demand of energy sources for urban, household and industrial facilities requires strategies development for seeking new energy sources. In recent years an important problem is to have energy storage, energy production and energy consumption which fulfill the environment friendly expectations. A lot of attention is devoted to renewable energy sources. One of the most attracting among them is energy production form geothermal sources. At a few meters below the earth’s surface the underground maintains a constant temperature in an approximation through the year allowing to withdraw heat in winter for heating needs and to surrender heat during summer for air-conditioning purposes. Heat pump is a rapidly developing technology for heating and domestic hot water production. Using ground as a heat source, heat exchange is carried out with heat pumps compound to vertical ground heat exchanger tubes that allows the heating and cooling of the buildings utilizing a single unit installation. Heat pump unit provides a high degree of productivity with moderate electric power consumption. In this paper a theoretical performance study of a vapor compression heat pump system with various natural and synthetic refrigerants (HFCs is presented. Operation mode of the heat pump unit was chosen according to European Standard EN14511-2:2007 and EN255-2. An influence of discharge temperature on system performance was evaluated at different boiling temperatures. The comparison of mass flow rate and coefficient of performance for considered refrigerants at constant cooling capacity and condensation temperature was performed.

  11. Application of an energy efficient casting ladle heating system used in the manufacture of stainless steel; Einsatz einer energieeffizienten Pfannenaufheizstation bei der Herstellung von Edelstahl

    Energy Technology Data Exchange (ETDEWEB)

    Poeschl, Markus [Edelstahlwerke Schmees GmbH, Langenfeld (Germany); Lodde, Marcus [Effizienz-Agentur NRW, Duisburg (Germany). prisma Consult GmbH


    In the melting area, the company has been using four conventional burners to heat the ladles. The existing flame burners heat the upside down ladles from below and consume massive amount of energy. Heat radiation and all of the waste gas are released into the facility. The material around the ladles is therefore heavily affected. The company has now installed a new energy efficient casting ladle heating system with a new kind of porous burner which heats the transport ladles without exposing them to an open flame. The combustion heat is channeled to specially adapted steel pipes via infrared radiation and convection flow. By doing this, the heat is directly transferred to the ladles and can be controlled in a more balanced manner. The company now saves around 61,400 m{sup 3}/a of natural gas, approx. 60 % of the energy required for the ladle heating and, as a result, 113.8 tonnes of CO{sub 2}-equivalent. The life span of the ladles can be increased by a factor of 2 due to the reduced exposure of the fire resistant materials. The resulting waste gas is collected and the waste heat will be reused in the facility in the future (facility heating 2011). Due to reduction in cleaning and carrying time of the ladles, Fr. Schmees expects an increase in productivity of the complete process. The heat radiation from the ladles has been reduced by 75 % which has led to a reduction of breakdowns. In addition, the noise level has sunk from 78.7 dB to 67.4 db. (orig.)

  12. Efficiency of steam reheating in heat recovery steam generator at thermal power plant with gas turbine topping

    Directory of Open Access Journals (Sweden)

    Romashova Olga


    Full Text Available Possibility of using alternative option to the displacement of regenerative heating is analyzed in this paper: application of heat recovery steam generator’s (HRSG thermal power for reheating of working medium that has passed steam turbine.

  13. Heat transfer study on convective–radiative semi-spherical fins with temperature-dependent properties and heat generation using efficient computational methods

    International Nuclear Information System (INIS)

    Atouei, S.A.; Hosseinzadeh, Kh.; Hatami, M.; Ghasemi, Seiyed E.; Sahebi, S.A.R.; Ganji, D.D.


    In this study, heat transfer and temperature distribution equations for semi-spherical convective–radiative porous fins are presented. Temperature-dependent heat generation, convection and radiation effects are considered and after deriving the governing equation, Least Square Method (LSM), Collocation Method (CM) and fourth order Runge-Kutta method (NUM) are applied for predicting the temperature distribution in the described fins. Results reveal that LSM has excellent agreement with numerical method, so can be suitable analytical method for solving the problem. Also, the effect of some physical parameters which are appeared in the mathematical formulation on fin surface temperature is investigated to show the effect of radiation and heat generation in a solid fin temperature. - Highlights: • Thermal analysis of a semi-spherical fin is investigated. • Collocation and Least Square Methods are applied on the problem. • Convection, radiation and heat generation is considered. • Physical results are compared to numerical outcomes.

  14. Planning and constructional instruments that support an energy-efficient supply of heat; Planungs- und Bauinstrumente zugunsten einer energieeffizienten Waermeversorgung

    Energy Technology Data Exchange (ETDEWEB)

    Renaud, P.; Bonnet, C. [Planair SA, Bureau d' ingenieurs SIA, La Sagne (Switzerland); Hoesli, B.; Wuethrich, M. [Hesse und Schwarze und Partner, Buero fuer Raumplanung AG, Zuerich (Switzerland); Gerheuser, F. W. [Polis, Politikberatung und Sozialforschung, Brugg (Switzerland)


    This comprehensive report for the Swiss Federal Office of Energy (SFOE) and the Cantons of Basel-Stadt, Berne, Geneva and Zurich presents the results of a study that examined how regulations in the planning and construction areas can be used to support the saving of energy, its efficient use and how the proportion of renewable sources of energy can be increased. Topics discussed include dense building, passive energy generation, obligatory refurbishing of existing building with high energy consumption, use of the 'Minergie' low energy-consumption standard for new and refurbished buildings, aid for energy refurbishment, co-ordination of the use of district heating, definition of intensive-farming areas, development of energy concepts with restrictions on energy consumption and carbon dioxide production as well as aids for negotiation and the development of target agreements. The report suggests an order of priority in which the measures should be considered and makes suggestions for action to be taken in various areas.

  15. Novel immobilization process of a thermophilic catalase: efficient purification by heat treatment and subsequent immobilization at high temperature. (United States)

    Xu, Juan; Luo, Hui; López, Claudia; Xiao, Jing; Chang, Yanhong


    The main goal of the present work is to investigate a novel process of purification and immobilization of a thermophilic catalase at high temperatures. The catalase, originated from Bacillus sp., was overexpressed in a recombinant Escherichia coli BL21(DE3)/pET28-CATHis and efficiently purified by heat treatment, achieving a threefold purification. The purified catalase was then immobilized onto an epoxy support at different temperatures (25, 40, and 55 °C). The immobilizate obtained at higher temperatures reached its maximum activity in a shorter time than that obtained at lower temperatures. Furthermore, immobilization at higher temperatures required a lower ionic strength than immobilization at lower temperatures. The characteristics of immobilized enzymes prepared at different temperatures were investigated. The high-temperature immobilizate (55 °C) showed the highest thermal stability, followed by the 40 °C immobilizate. And the high-temperature immobilizate (55 °C) had slightly higher operational stability than the 25 °C immobilizate. All of the immobilized catalase preparations showed higher stability than the free enzyme at alkaline pH 10.0, while the alkali resistance of the 25 °C immobilizate was slightly better than that of the 40 and 55 °C immobilizates.

  16. Molecular symmetry determines the mechanism of a very efficient ultrafast excitation-to-heat conversion in Ni-substituted chlorophylls. (United States)

    Pilch, Mariusz; Dudkowiak, Alina; Jurzyk, Barbara; Lukasiewicz, Jędrzej; Susz, Anna; Stochel, Grażyna; Fiedor, Leszek


    In the Ni-substituted chlorophylls, an ultrafast (symmetry of a ligand field created in the central cavity. The central N-Ni(2+) bonds, formed via the donation of two electrons from each of the sp(2) orbitals of two central nitrogens to an empty [Formula: see text] hybrid centered on Ni(2+), have a considerable covalent character. The extreme rate of excited state relaxation is then not due to a ladder of the metal centered d-states, often invoked in metalloporphyrins, but seems to result from a peculiar topology of the potential energy surface (a saddle-shaped crossing) due to the covalent character of the N-Ni(2+) bonds. This is confirmed by a strong 0→0 character of electronic transitions in these complexes indicating a similarity of their equilibrium geometries in the ground (S(0)) and the excited states (both Q(X) and Q(Y)). The excitation energy is very efficiently converted into molecular vibrations and dissipated as heat, involving the central Ni(2+). These Ni-substituted pigments pose a fine exemplification of symmetry control over properties of excited states of transition metal complexes. Copyright © 2012. Published by Elsevier B.V.

  17. High systemic and testicular thermolytic efficiency during heat tolerance test reflects better semen quality in rams of tropical breeds (United States)

    Kahwage, Priscila Reis; Esteves, Sérgio Novita; Jacinto, Manuel Antônio Chagas; Junior, Waldomiro Barioni; Pezzopane, José Ricardo Macedo; de Andrade Pantoja, Messy Hannear; Bosi, Cristian; Miguel, Maria Carolina Villani; Mahlmeister, Kaue; Garcia, Alexandre Rossetto


    This study aimed to assess the capacity of Morada Nova (MN) and Santa Inês (SIN) rams to maintain body and testicular homeothermy under thermal challenge. For 5 days in the summer, 16 males (SIN = 7 and MN = 9) underwent a heat tolerance test, i.e., period 1—animals maintained in the shade (11 to 12 h); period 2—animals exposed to sunlight (12 to 13 h); and period 3—animals returned to the shade (13 to 14 h). The respiratory rate, heart rate, rectal temperature, and infrared surface temperatures (IRT) of the trunk, back, eyeball, and testicles were assessed in each period. The index of capacity of tolerance to insolation (ICTI), which indicates the animals' level of adaptability, was calculated for each animal. Semen quality and testicular parenchyma integrity were assessed before and after the thermal challenge. Statistical analyses were performed at 5% significance. In period 1, the variables had baseline values for both genotypes. In period 2, the variables involved in thermolysis significantly increased ( P animals were considered resilient to a thermal challenge. In addition, infrared thermography was an efficient tool to verify body and testicular thermoregulation.

  18. Geophysical Monitoring of Geodynamic Processes of Central Armenia Earth Crust (United States)

    Avetyan, R.; Pashayan, R.


    The method of geophysical monitoring of earth crust was introduced. It allows by continuous supervision to track modern geodynamic processes of Armenia. Methodological practices of monitoring come down to allocation of a signal which reflects deformation of rocks. The indicators of deformations are not only deviations of geophysical indicators from certain background values, but also parameters of variations of these indicators. Data on changes of parameters of barometric efficiency and saw tooth oscillations of underground water level before seismic events were received. Low-amplitude periodic fluctuations of water level are the reflection of geodynamic processes taking place in upper levels of earth crust. There were recorded fluctuations of underground water level resulting from luni-solar tides and enabling to control the systems of borehole-bed in changes of voluminous deformations. The slow lowering (raising) of underground water level in the form of trend reflects long-period changes of stress-deformative state of environment. Application of method promotes identification of medium-term precursors on anomalous events of variations of geomagnetic field, change of content of subsoil radon, dynamics of level of underground water, geochemistry and water temperature. Increase of activity of geodynamic processes in Central Armenian tectonic complex is observed to change macro component Na+, Ca2+, Mg2-, CL-, SO42-, HCO3-, H4SiO4, pH and gas - CO2 structure of mineral water. Modern geodynamic movements of earth crust of Armenia are the result of seismic processes and active geodynamics of deep faults of longitudinal and transversal stretching. Key Words: monitoring, hydrogeodynamics, geomagnetic field, seismicity, deformation, earth crust

  19. Efficient ground-state cooling of an ion in a large room-temperature linear Paul trap with a sub-Hertz heating rate

    DEFF Research Database (Denmark)

    Poulsen, Gregers; Miroshnychenko, Yevhen; Drewsen, Michael


    We demonstrate efficient resolved sideband laser cooling (99±1% ground-state population) of a single 40Ca+ ion in a large linear Paul trap (electrode spacing of 7 mm) operated at an rf drive frequency of just 3.7 MHz. For ion oscillation frequencies in the range 280–585 kHz, heating rates below...

  20. Evaluation of the efficiency face to the NO{sub x} emissions from European gas-fired heat process equipment

    Energy Technology Data Exchange (ETDEWEB)

    Fourniguet, M.J.; Quinqueneau, A. [Gaz de France, Saint-Denis la Plaine (France); Karll, B. [Dansk Gasteknisk Center, Hoersholm (Denmark); Breithaupt, P. Gasunie [Gasunie, Groningue (Netherlands); Jonsson, O. [Svensk Gastekniskt Center AB, Malmoe (Sweden); Navarri, P. [CETIAT, Villeurbanne (France)


    In the frame of the project, tests have been performed by Gaz de France, CETIAT, DGC, GASUNIE and SGC on 35 European industrial sites in order to depict what the European industry using natural gas as an energy source actually looks like in 1997, the levels of efficiency and nitrogen oxides (NOx) emissions currently being achieved. These 35 industrial sites were chosen among the three following sectors: steam or water boilers, engines or turbines and industrial processes (food processing industry, metallurgy, ceramic, paper and textile industries). The partners focused on relatively new installations or newly retrofitted which were equipped with low NOx technologies. To create an open database between the Partners, a common EXCEL sheet has been defined and used to report the results for the three sectors concerned including principally the following items: General background on the site: it includes the description of the installation, technical characteristics of the furnace, the boiler or the engine, operating scenarios, gas total rating, and depending of the type of installation power density, rated electric power or production rate; Description of the equipment: it includes, if available, the control system of the heating equipment and the low NOx techniques identified; Description of the measurement techniques: In order to compensate for the lack of international standard, this part has been particularly detailed. It includes the description of flue gas analysers (CO, CO{sub 2}, O{sub 2}, NOx, CH{sub 4}, UHC, N{sub 2}O, VOC), metering and pressure and temperature probes in terms of measurement principle, supplier, measurement rang and accuracy and gas calibration. It precise the position of the sampling points and the type of the sampling line; Results: The operating conditions (atmospheric data, type of natural gas burnt during the test and measurement period) are given before the results themselves (complete flue gas analysis and determination of combustion

  1. High efficient heat pump system using storage tanks to increase COP by means of the ISEC concept - Part 1: Model validation

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus; Elmegaard, Brian; Markussen, Wiebke B.


    The purpose of the ISEC concept is to provide a high-efficient heat pump system for hot water production.The ISEC concept uses two storage tanks for the water, one discharged and one charged. Hot water for theindustrial process is tapped from the charged tank, while the other tank is charging....... This result in a lower condensingtemperature than if the water was heated in one step. Two test setups were built, one to test the performanceof the heat pump gradually heating the water and one to investigate the stratification in the storage tanks.Furthermore, a dynamic model of the system was implemented...... in Dymola, and validated by the use of testdata from the two experimental setups. This paper shows that there is a good consistency between the modeland the experimental tests....

  2. Numerical analysis of crust formation in molten core-concrete interaction using MPS method

    International Nuclear Information System (INIS)

    Seiichi, Koshizuka; Shoji, Matsuura; Mizue, Sekine; Yoshiaki, Oka


    A two-dimensional code is developed for molten core-concrete interaction (MCCI) based on Moving Particle Semi-implicit (MPS) method. Heat transfer is calculated without any specific correlations. A particle can be changed to a moving (fluid) or fixed (solid) particle corresponding to its enthalpy, which provide the phase change model for particles. The phase change model is verified by one-dimensional test calculations. Nucleate boiling and radiation heat transfers are considered between the core debris and the water pool. The developed code is applied to SWISS-2 experiment in which stainless steel is used as the melt material. Calculated heat flux to the water pool agrees well with the experiment, though the ablation speed in the concrete is a little slower. A stable crust is formed in a short time after water is poured in and the heat flux to the water pool rapidly decreases. MACE-M0 using corium is also analyzed. The ablation speed of concrete is slower than that of SWISS-2 because of low heat conduction in corium. An unlimited geometry is analyzed by setting the cyclic boundary condition on the sides. When the crust is broken by the decomposition gas, heat transfer to the water pool is kept high for a longer time because the crust re-formation is delayed. (author)

  3. The Mafic Lower Crust of Neoproterozoic age beneath Western Arabia: Implications for Understanding African Lower Crust (United States)

    Stern, R. J.; Mooney, W. D.


    We review evidence that the lower crust of Arabia - and by implication, that beneath much of Africa was formed at the same time as the upper crust, rather than being a product of Cenozoic magmatic underplating. Arabia is a recent orphan of Africa, separated by opening of the Red Sea ~20 Ma, so our understanding of its lower crust provides insights into that of Africa. Arabian Shield (exposed in W. Arabia) is mostly Neoproterozoic (880-540 Ma) reflecting a 300-million year process of continental crustal growth due to amalgamated juvenile magmatic arcs welded together by granitoid intrusions that make up as much as 50% of the Shield's surface. Seismic refraction studies of SW Arabia (Mooney et al., 1985) reveal two layers, each ~20 km thick, separated by a well-defined Conrad discontinuity. The upper crust has average Vp ~6.3 km/sec whereas the lower crust has average Vp ~7.0 km/sec, corresponding to a granitic upper crust and gabbroic lower crust. Neogene (Yemen to Syria. Many of these lavas contain xenoliths, providing a remarkable glimpse of the lower-crustal and upper-mantle lithosphere beneath W. Arabia. Lower crustal xenoliths brought up in 8 harrats in Saudi Arabia, Jordan, and Syria are mostly 2-pyroxene granulites of igneous (gabbroic, anorthositic, and dioritic) origin. They contain plagioclase, orthopyroxene, and clinopyroxene, and a few contain garnet and rare amphibole and yield mineral-equilibrium temperatures of 700-900°C. Pyroxene-rich and plagioclase-rich suites have mean Al2O3 contents of 13% and 19%, respectively: otherwise the two groups have similar elemental compositions, with ~50% SiO2 and ~1% TiO2, with low K2O (time. Lower crust of Arabia clearly formed during Neoproterozoic time, about the same time as its upper crust complement; a similar origin for the lower crust beneath the broad expanses of Neoproterozoic crust in N and E Africa is likely. There is no evidence that any of the mafic lower crust of Arabia formed due to underplating by

  4. The Influences of Quantum Coherence on the Positive Work and the Efficiency of Quantum Heat Engine with Working Substance of Two-Qubit Heisenberg XXX Model (United States)

    Peng, Hu-Ping; Fang, Mao-Fa; Yu, Min; Zou, Hong-Mei


    We study the influences of quantum coherence on the positive work and the efficiency of quantum heat engine (QHE) based on working substance of two-qubit Heisenberg model under a constant external magnetic field. By using analytical and numerical solution, we give the relation expressions for both the positive work and the efficiency with quantum coherence, and in detail discuss the effects of the quantum coherence on the positive work and the efficiency of QHE in the absence or presence of external magnetic field, respectively.

  5. Development of technologies on innovative-simplified nuclear power plant using high-efficiency steam injectors (2) analysis of heat balance of innovative-simplified nuclear power plant

    International Nuclear Information System (INIS)

    Goto, S.; Ohmori, S.; Mori, M.


    It is possible to establish simplified system with reduced space and total equipment weight using high-efficiency Steam Injector (SI) instead of low-pressure feedwater heaters in Nuclear Power Plant (NPP)(1)-(6). The SI works as a heat exchanger through direct contact between feedwater from the condensers and extracted steam from the turbines. It can get a higher pressure than supplied steam pressure, so it can reduce the feedwater pumps. The maintenance and reliability are still higher because SI has no movable parts. This paper describes the analysis of the heat balance and plant efficiency of this Innovative- Simplified NPP with high-efficiency SI. The plant efficiency is compared with the electric power of 1100MWe-class BWR system and the Innovative- Simplified BWR system with SI. The SI model is adapted into the heat balance simulator with a simplified model. The results show plant efficiencies of the Innovated-Simplified BWR system are almost equal to the original BWR one. The present research is one of the projects that are carried out by Tokyo Electric Power Company, Toshiba Corporation, and six Universities in Japan, funded from the Institute of Applied Energy (IAE) of Japan as the national public research-funded program. (authors)

  6. Development of technologies on innovative-simplified nuclear power plant using high-efficiency steam injectors. (2) Analysis of heat balance of innovative-simplified nuclear power plant

    International Nuclear Information System (INIS)

    Goto, Shoji; Ohmori, Shuichi; Mori, Mitchitsugu


    It is possible to established simplified systems and reduced space and equipments using high-efficiency Steam Injector (SI) instead of low-pressure feed water heaters in Nuclear Power Plant (NPP). The SI works as a heat exchanger through direct contact between feedwater from condenser and extracted steam from turbine. It can get a higher pressure than supplied steam pressure, so it can reduce the feedwater pumps. The maintenance and reliability are still higher because SI has no movable parts. This paper describes the analysis of the heat balance and plant efficiency of this Innovative-Simplified NPP with high-efficiency SI. The plant efficiency is compared with the electric power of 1100MWe class original BWR system and the Innovative-Simplified BWR system with SI. The SI model is adapted into the heat balance simulator with a simplified model. The results show plant efficiencies of the Innovated-Simplified BWR system are almost equal to the original BWR one. The present research is one of the projects that are carried out by Tokyo Electric Power Company, Toshiba Corporation, and six Universities in Japan, funded from the Institute of Applied Energy (IAE) of Japan as the national public research-funded program. (author)

  7. Degradation efficiencies of azo dye Acid Orange 7 by the interaction of heat, UV and anions with common oxidants: persulfate, peroxymonosulfate and hydrogen peroxide. (United States)

    Yang, Shiying; Wang, Ping; Yang, Xin; Shan, Liang; Zhang, Wenyi; Shao, Xueting; Niu, Rui


    In this paper, the degradation of azo dye Acid Orange 7 (AO7) by three common peroxides (persulfate (PS), peroxymonosulfate (PMS) or hydrogen peroxide (H(2)O(2))) under various activation conditions, i.e., heat (25-80 degrees C), UV light (254 nm), or anions (SO(4)(2-), NO(3)(-), CO(3)(2-), HCO(3)(-), HPO(4)(2-), and Cl(-)), was investigated. The order of AO7 degradation efficiencies by heat activation is PS>PMS>H(2)O(2). PS oxidation activated by heat (>50 degrees C) is an effective degradation technology, while PMS and H(2)O(2) are hardly activated. When assisted by UV, peroxides could all be activated and degrade AO7 quickly. The order is PS>H(2)O(2)>PMS. We activated peroxides, for the first time, by using some anions and compared the subsequently degradation efficiencies of AO7. It was found that PMS could be activated by some anions, but PS and H(2)O(2) cannot. The activation efficiencies of PMS by SO(4)(2-) and NO(3)(-) are negligible, whereas remarkable by HCO(3)(-), HPO(4)(2-), Cl(-) and CO(3)(2-). For HCO(3)(-), HPO(4)(2-) and Cl(-), the activation efficiencies become higher with the increase of anion concentration. For CO(3)(2-), however, the activation efficiency is higher at lower concentration. 2010 Elsevier B.V. All rights reserved.

  8. Probabilistic assessment of the potential indoor air impacts of vent-free gas heating appliances in energy-efficient homes in the united states. (United States)

    Whitmyre, Gary K; Pandian, Muhilan D


    Use of vent-free gas heating appliances for supplemental heating in U.S. homes is increasing. However, there is currently a lack of information on the potential impact of these appliances on indoor air quality for homes constructed according to energy-efficient and green building standards. A probabilistic analysis was conducted to estimate the impact of vent-free gas heating appliances on indoor air concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), carbon dioxide (CO2), water vapor, and oxygen in "tight" energy-efficient homes in the U.S. A total of 20,000 simulations were conducted for each DOE Heating Region to capture a wide range of home sizes, appliance features, and conditions, by varying a number of parameters, e.g., room volume, house volume, outdoor humidity, air exchange rates, appliance input rates (Btu/hr), and house heat loss factors. Predicted airborne levels of CO were below the U. S. Environmental Protection Agency (USEPA) standard of 9 ppm for all modeled cases. The airborne concentrations of NO2 were below the CPSC guideline of 0.3 ppm and the Health Canada benchmark of 0.25 ppm in all cases, and were below the WHO standard of 0.11 ppm in 99 to 100 percent of all cases. Predicted levels of CO2 were below the Health Canada standard of 3500 ppm for all simulated cases. Oxygen levels in the room of vent-free heating appliance use were not significantly reduced. The great majority of cases in all DOE Regions were associated with relative humidity (RH) levels from all indoor water vapor sources that were less than the USEPA-recommended 70% RH maximum to avoid active mold and mildew growth. The conclusion of this investigation is that when installed in accordance with the manufacturer's instructions, vent-free gas heating appliances maintain acceptable indoor air quality in tight energy-efficient homes, as defined by the standards referenced in this report. Probabilistic modeling of indoor air concentrations of carbon monoxide (CO

  9. 3-D velocity structure of upper crust beneath NW Bohemia/Vogtland

    DEFF Research Database (Denmark)

    Mousavi, S. S.; Korn, M.; Bauer, K.

    and enhanced heat flow. This region is an excellent location for an ICDP drilling project targeted to a better understanding of the crust in an active magmatic environment. The data set were taken from permanent and temporary seismic networks in Germany and Czech Republic from 2000 to 2010, as well as active......We present preliminary results from a travel time tomography investigation of the upper crust beneath west Bohemia/Vogtland region which is characterized by a series of phenomena like occurrence of repeated earthquake swarms, surface exhalation, CO2 enriched fluids, mofettes, mineral springs...

  10. Basin Excavation, Lower Crust, Composition, and Bulk Moon Mass balance in Light of a Thin Crust (United States)

    Jolliff, B. L.; Korotev, R. L.; Ziegler, R. A.


    New lunar gravity results from GRAIL have been interpreted to reflect an overall thin and low-density lunar crust. Accordingly, crustal thickness has been modeled as ranging from 0 to 60 km, with thinnest crust at the locations of Crisium and Moscoviense basins and thickest crust in the central farside highlands. The thin crust has cosmochemical significance, namely in terms of implications for the Moon s bulk composition, especially refractory lithophile elements that are strongly concentrated in the crust. Wieczorek et al. concluded that the bulk Moon need not be enriched compared to Earth in refractory lithophile elements such as Al. Less Al in the crust means less Al has been extracted from the mantle, permitting relatively low bulk lunar mantle Al contents and low pre- and post-crust-extraction values for the mantle (or the upper mantle if only the upper mantle underwent LMO melting). Simple mass-balance calculations using the method of [4] suggests that the same conclusion might hold for Th and the entire suite of refractory lithophile elements that are incompatible in olivine and pyroxene, including the KREEP elements, that are likewise concentrated in the crust.

  11. High Efficiency Water Heating Technology Development Final Report, Part II: CO2 and Absorption-Based Residential Heat Pump Water Heater Development

    Energy Technology Data Exchange (ETDEWEB)

    Gluesenkamp, Kyle R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Patel, Viral K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mandel, Bracha T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); de Almeida, Valmor F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)


    The two objectives of this project were to 1.demonstrate an affordable path to an ENERGY STAR qualified electric heat pump water heater (HPWH) based on low-global warming potential (GWP) CO2 refrigerant, and 2.demonstrate an affordable path to a gas-fired absorption-based heat pump water heater with a gas energy factor (EF) greater than 1.0. The first objective has been met, and the project has identified a promising low-cost option capable of meeting the second objective. This report documents the process followed and results obtained in addressing these objectives.

  12. DaMaSCUS-CRUST: Dark Matter Simulation Code for Underground Scatterings - Crust Edition (United States)

    Emken, Timon; Kouvaris, Chris


    DaMaSCUS-CRUST determines the critical cross-section for strongly interacting DM for various direct detection experiments systematically and precisely using Monte Carlo simulations of DM trajectories inside the Earth's crust, atmosphere, or any kind of shielding. Above a critical dark matter-nucleus scattering cross section, any terrestrial direct detection experiment loses sensitivity to dark matter, since the Earth crust, atmosphere, and potential shielding layers start to block off the dark matter particles. This critical cross section is commonly determined by describing the average energy loss of the dark matter particles analytically. However, this treatment overestimates the stopping power of the Earth crust; therefore, the obtained bounds should be considered as conservative. DaMaSCUS-CRUST is a modified version of DaMaSCUS (ascl:1706.003) that accounts for shielding effects and returns a precise exclusion band.

  13. OECD MCCI Small-Scale Water Ingression and Crust Strength tests (SSWICS) design report, Rev. 2 October 31, 2002

    International Nuclear Information System (INIS)

    Farmer, M.; Lomperski, S.; Kilsdonk, D.; Aeschlimann, B.; Pfeiffer, P.


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are planned to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium (∼φ30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. A description of the test apparatus, instrumentation, data reduction, and test matrix are the subject of the first portion of this report. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The introduction of a thermal gradient across the crust is thought to be important for these tests because of uncertainty in the magnitude of the thermal stresses and thus their relative

  14. OECD MCCI Small-Scale Water Ingression and Crust Strength tests (SSWICS) design report, Rev. 2 October 31, 2002.

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, M.; Lomperski, S.; Kilsdonk, D.; Aeschlimann, B.; Pfeiffer, P. (Nuclear Engineering Division); (NRC)


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are planned to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium ({approx}{phi}30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. A description of the test apparatus, instrumentation, data reduction, and test matrix are the subject of the first portion of this report. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The introduction of a thermal gradient across the crust is thought to be important for these tests because of uncertainty in the magnitude of the thermal stresses and thus their

  15. Efficiency study about solar water heating system on the camping place Stortemelk situated in the island Vlieland


    Giró Batalla, Ramon


    I will create two projects that are very similarn in nature. The first (Solar water heating system) is a heating system situated on an island called Vlieland in North of Holland near Leeuwarden. The system function is to create sanitary hot water and floor heating by using thermal solar energy and natural gas. The second project (heating and cooling system) is a system that is installed in my university called Hogeschool NHL. This system is reversible and is capable of producing hot and cool ...

  16. Effects of steam pretreatment and co-production with ethanol on the energy efficiency and process economics of combined biogas, heat and electricity production from industrial hemp (United States)


    Background The study presented here has used the commercial flow sheeting program Aspen Plus™ to evaluate techno-economic aspects of large-scale hemp-based processes for producing transportation fuels. The co-production of biogas, district heat and power from chopped and steam-pretreated hemp, and the co-production of ethanol, biogas, heat and power from steam-pretreated hemp were analysed. The analyses include assessments of heat demand, energy efficiency and process economics in terms of annual cash flows and minimum biogas and ethanol selling prices (MBSP and MESP). Results Producing biogas, heat and power from chopped hemp has the highest overall energy efficiency, 84% of the theoretical maximum (based on lower heating values), providing that the maximum capacity of district heat is delivered. The combined production of ethanol, biogas, heat and power has the highest energy efficiency (49%) if district heat is not produced. Neither the inclusion of steam pretreatment nor co-production with ethanol has a large impact on the MBSP. Ethanol is more expensive to produce than biogas is, but this is compensated for by its higher market price. None of the scenarios examined are economically viable, since the MBSP (EUR 103–128 per MWh) is higher than the market price of biogas (EUR 67 per MWh). The largest contribution to the cost is the cost of feedstock. Decreasing the retention time in the biogas process for low solids streams by partly replacing continuous stirred tank reactors by high-rate bioreactors decreases the MBSP. Also, recycling part of the liquid from the effluent from anaerobic digestion decreases the MBSP. The production and prices of methane and ethanol influence the process economics more than the production and prices of electricity and district heat. Conclusions To reduce the production cost of ethanol and biogas from biomass, the use of feedstocks that are cheaper than hemp, give higher output of ethanol and biogas, or combined production with

  17. Crust formation in drying colloidal suspensions

    KAUST Repository

    Style, R. W.


    During the drying of colloidal suspensions, the desiccation process causes the suspension near the air interface to consolidate into a connected porous matrix or crust. Fluid transport in the porous medium is governed by Darcy\\'s law and the equations of poroelasticity, while the equations of colloid physics govern processes in the suspension. We derive new equations describing this process, including unique boundary conditions coupling the two regions, yielding a moving-boundary model of the concentration and stress profiles during drying. A solution is found for the steady-state growth of a nedimensional crust during constant evaporation rate from the surface. The solution is used to demonstrate the importance of the system boundary conditions on stress profiles and diffusivity in a drying crust. © 2011 The Royal Society.

  18. Elemental composition of the Martian crust. (United States)

    McSween, Harry Y; Taylor, G Jeffrey; Wyatt, Michael B


    The composition of Mars' crust records the planet's integrated geologic history and provides clues to its differentiation. Spacecraft and meteorite data now provide a global view of the chemistry of the igneous crust that can be used to assess this history. Surface rocks on Mars are dominantly tholeiitic basalts formed by extensive partial melting and are not highly weathered. Siliceous or calc-alkaline rocks produced by melting and/or fractional crystallization of hydrated, recycled mantle sources, and silica-poor rocks produced by limited melting of alkali-rich mantle sources, are uncommon or absent. Spacecraft data suggest that martian meteorites are not representative of older, more voluminous crust and prompt questions about their use in defining diagnostic geochemical characteristics and in constraining mantle compositional models for Mars.

  19. Deep-ocean ferromanganese crusts and nodules (United States)

    Hein, James R.; Koschinsky, Andrea


    Ferromanganese crusts and nodules may provide a future resource for a large variety of metals, including many that are essential for emerging high- and green-technology applications. A brief review of nodules and crusts provides a setting for a discussion on the latest (past 10 years) research related to the geochemistry of sequestration of metals from seawater. Special attention is given to cobalt, nickel, titanium, rare earth elements and yttrium, bismuth, platinum, tungsten, tantalum, hafnium, tellurium, molybdenum, niobium, zirconium, and lithium. Sequestration from seawater by sorption, surface oxidation, substitution, and precipitation of discrete phases is discussed. Mechanisms of metal enrichment reflect modes of formation of the crusts and nodules, such as hydrogenetic (from seawater), diagenetic (from porewaters), and mixed diagenetic–hydrogenetic processes.

  20. Phenotypically divergent classification of preweaned heifer calves for feed efficiency indexes and their correlations with heat production and thermography. (United States)

    Leão, J M; Coelho, S G; Machado, F S; Azevedo, R A; Lima, J A M; Carneiro, J C; Lage, C F A; Ferreira, A L; Pereira, L G R; Tomich, T R; Campos, M M


    The aims of this study were (1) to assess if there is phenotypical divergence for feed efficiency (FE) during the preweaning phase; (2) if FE is correlated with heat production (HP) measured by the face mask method or (3) by surface skin temperature via thermography, and (4) whether these methods are applicable to preweaned calves. Holstein × Gyr heifer calves (n = 36, birth body weight = 32.4 ± 6.6 kg) were enrolled and on trial between 4 and 12 wk of age and were classified into 2 residual feed intake (RFI) and residual body weight gain (RG) groups: high efficiency (HE; RFI, n = 10; and RG, n = 9) and low efficiency (LE; RFI, n = 10; and RG, n = 8). Calves were fed milk (6 L/d) and solid feed (95% starter and 5% chopped Tifton 85 hay, as fed). Growth was monitored weekly and feed intake (milk and solid feed) daily, during the whole period. Gas exchanges (O 2 consumption and production of CO 2 and CH 4 ) were obtained using a face mask at 45 ± 5 d of age and HP was estimated. Maximum temperatures were measured at 7 sites with an infrared camera at 62 ± 7 d of age. There was divergence in RFI and RG. Respectively, HE and LE calves had RFI of -0.14 and 0.13 kg/d, and RG of 0.05 and -0.07 kg/d. Dry matter intake was 15% lower in HE-RFI compared with LE-RFI, but no differences were observed in average daily weight gain. Within the RG test, no differences were observed in dry matter intake or average daily gain. The HE-RFI calves consumed less O 2 (L/d) and produced less CO 2 (L/d). Heart rate and HP were lower for HE-RFI calves compared with LE-RFI. Residual feed intake was correlated with HP (r = 0.48), O 2 consumption (r = 0.48), CO 2 production (r = 0.48), and heart rate (r = 0.40). No differences were observed in HP and gas exchanges between RG groups. Methane production was null in both groups. Eye temperature measured by thermography was 0.5°C greater in HE-RG than LE-RG calves. Differences in skin temperature between HE and LE calves were not observed at

  1. Hafnium isotope stratigraphy of ferromanganese crusts (United States)

    Lee, D.-C.; Halliday, A.N.; Hein, J.R.; Burton, K.W.; Christensen, J.N.; Gunther, D.


    A Cenozoic record of hafnium isotopic compositions of central Pacific deep water has been obtained from two ferromanganese crusts. The crusts are separated by more than 3000 kilometers but display similar secular variations. Significant fluctuations in hafnium isotopic composition occurred in the Eocene and Oligocene, possibly related to direct advection from the Indian and Atlantic oceans. Hafnium isotopic compositions have remained approximately uniform for the past 20 million years, probably reflecting increased isolation of the central Pacific. The mechanisms responsible for the increase in 87Sr/86Sr in seawater through the Cenozoic apparently had no effect on central Pacific deep-water hafnium.

  2. Tungsten Stable Isotope Compositions of Ferromanganese Crusts (United States)

    Abraham, K.; Barling, J.; Hein, J. R.; Schauble, E. A.; Halliday, A. N.


    We report the first accurate and precise data for mass-dependent fractionation of tungsten (W) stable isotopes, using a double spike technique and MC-ICPMS. Results are expressed relative to the NIST 3136 W isotope standard as per mil deviations in 186W/184W (δ186W). Although heavy element mass-dependent fractionations are expected to be small, Tl and U both display significant low temperature isotopic fractionations. Theoretical calculations indicate that W nuclear volume isotopic effects should be smaller than mass-dependent fractionations at low temperatures. Hydrogenetic ferromanganese (Fe-Mn) crusts precipitate directly from seawater and have been used as paleoceanographic recorders of temporal changes in seawater chemistry. Crusts are strongly enriched in W and other metals, and are a promising medium for exploring W isotopic variability. Tungsten has a relatively long residence time in seawater of ~61,000 years, mainly as the tungstate ion (WO42-). Water depth profiles show conservative behaviour. During adsorption on Fe-Mn crusts, W species form inner-sphere complexes in the hexavalent (W6+) state. The major host phase is thought to be Mn oxides and the lighter W isotope is expected to be absorbed preferentially. Surface scrapings of 13 globally distributed hydrogenetic Fe-Mn crusts display δ186W from -0.08 to -0.22‰ (±0.03‰, 2sd). A trend toward lighter W isotope composition exists with increasing water depth (~1500 to ~5200m) and W concentration. One hydrothermal Mn-oxide sample is anomalously light and Mn nodules are both heavy and light relative to Fe-Mn crusts. Tungsten speciation depends on concentration, pH, and time in solution and is not well understood because of the extremely slow kinetics of the reactions. In addition, speciation of aqueous and/or adsorbed species might be sensitive to pressure, showing similar thermodynamic stability but different effective volumes. Thus, W stable isotopes might be used as a water-depth barometer in

  3. The influence of the crust layer on RPV structural failure under severe accident condition

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Jianfeng, E-mail: [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology Hangzhou, Zhejiang 310032 (China); Engineering Research Center of Process Equipment and Re-manufacturing, Ministry of Education (China); Li, Xiangqing [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology Hangzhou, Zhejiang 310032 (China); Bao, Shiyi [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology Hangzhou, Zhejiang 310032 (China); Engineering Research Center of Process Equipment and Re-manufacturing, Ministry of Education (China); Luo, Lijia [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology Hangzhou, Zhejiang 310032 (China); Gao, Zengliang [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology Hangzhou, Zhejiang 310032 (China); Engineering Research Center of Process Equipment and Re-manufacturing, Ministry of Education (China)


    Highlights: • The crust layer greatly affects the RPV structural behavior. • The RPV failure is investigated in depth under severe accident. • The creep and plastic damage mainly contribute to RPV failure. • An elastic core in RPV wall is essential for ensuring RPV integrity. • The multiaxial state of stress accelerates the total damage evolution. - Abstract: The so called ‘in-vessel retention (IVR)’ is regarded as a severe accident (SA) mitigation strategy, which is widely used in most of advanced nuclear power plants. The effectiveness of IVR strategy is to employ the external water flooding to cool the reactor pressure vessel (RPV). The RPV integrity has to be maintained within a required period during the IVR period. The degraded melting core is assumed to be arrested in the lower head (LH) to form the melting pool that is bounded by upper, side and lower crusts. Consequently, the existence of the crust layer greatly affects the RPV structural behavior as well as failure process. In order to disclose this influence caused by the crust layer, a detailed investigation is conducted by using numerical simulation on the two RPVs with and without crust layer respectively. Taking the RPV without crust layer as a basis for the comparison, the present study assesses the likelihood and potential failure location, time and mode of the LH under the loadings of the critical heat flux (CHF) and slight internal pressure. Due to the high temperature melt on the inside and nucleate boiling on the outside, the RPV integrity is found to be compromised by melt-through, creep, elasticity, plasticity as well as thermal expansion. Through in-depth investigation, it is found that the creep and plasticity are of vital importance to the final structural failure, and the introduction of crust layer results in a significant change on field parameters in terms of temperature, deformation, stress(strain), triaxiality factor and total damage.

  4. Crust-ocean interactions during midocean ridge eruptions (United States)

    Baker, E. T.


    Eruptions are the "quantum event" of crustal accretion, occurring daily to monthly (depending on spreading rate) along the global midocean ridge system. The number of eruptions detected and responded to remain very few, however, so our knowledge of the magnitude and rate of crust-ocean interaction at the instant of an eruption is almost entirely circumstantial. The discovery of uniquely different plumes over a 2008 eruption on the NE Lau spreading center greatly broadened the known range of eruption-initiated transfer of heat, chemicals, and perhaps biota from the crust to the ocean. Serendipitous observations and rapid response cruises have now documented that the "event (mega-) plumes" accompanying eruptions range over a factor of 100 in volume (1-150 km3), yet maintain a distinctive and consistent chemical signature (much lower 3He/heat and Mn/heat and higher H2/heat than typical black smokers). Confirmed event plumes have formed at spreading rates from 55-~90 mm/yr, with some incompletely sampled but "event-like" plumes observed at even slower rates (11-30 mm/yr; Gakkel and Carlsberg Ridges). Presently, only four event plumes can be associated with specific eruptions. Large event plumes in the NE Pacific were found over thick (up to ~75 m), voluminous, and slowly extruded pillow mounds. The 2008 eruption on the fast-spreading NE Lau spreading center demonstrated that thin (a few meters), small, and rapidly emplaced sheet flows can generate smaller event plumes. Available evidence suggests that massive fluid discharge occurs virtually simultaneously with an eruption. At Gorda Ridge in 1996, eruption-indicative seismicity began on the same day and location an event plume was found. At Axial Volcano in 1998, moorings 2 km apart both recorded the appearance of a >100-m-thick plume within minutes of the start of a 72-min-long sheet flow eruption. These observations support inferences from plume modeling and chemistry that event plume generation time is hours, not

  5. Drift of continental rafts with asymmetric heating. (United States)

    Knopoff, L; Poehls, K A; Smith, R C


    A laboratory model of a lithospheric raft is propelled through a viscous asthenospheric layer with constant velocity of scaled magnitude appropriate to continental drift. The propulsion is due to differential heat concentration in the model oceanic and continental crusts.

  6. A relatively reduced Hadean continental crust (United States)

    Yang, Xiaozhi; Gaillard, Fabrice; Scaillet, Bruno


    Among the physical and chemical parameters used to characterize the Earth, oxidation state, as reflected by its prevailing oxygen fugacity (fO2), is a particularly important one. It controls many physicochemical properties and geological processes of the Earth's different reservoirs, and affects the partitioning of elements between coexisting phases and the speciation of degassed volatiles in melts. In the past decades, numerous studies have been conducted to document the evolution of mantle and atmospheric oxidation state with time and in particular the possible transition from an early reduced state to the present oxidized conditions. So far, it has been established that the oxidation state of the uppermost mantle is within ±2 log units of the quartz-fayalite-magnetite (QFM) buffer, probably back to ~4.4 billion years ago (Ga) based on trace-elements studies of mantle-derived komatiites, kimberlites, basalts, volcanics and zircons, and that the O2 levels of atmosphere were initially low and rose markedly ~2.3 Ga known as the Great Oxidation Event (GOE), progressively reaching its present oxidation state of ~10 log units above QFM. In contrast, the secular evolution of oxidation state of the continental crust, an important boundary separating the underlying upper mantle from the surrounding atmosphere and buffering the exchanges and interactions between the Earth's interior and exterior, has rarely been addressed, although the presence of evolved crustal materials on the Earth can be traced back to ~4.4 Ga, e.g. by detrital zircons. Zircon is a common accessory mineral in nature, occurring in a wide variety of igneous, sedimentary and metamorphic rocks, and is almost ubiquitous in crustal rocks. The physical and chemical durability of zircons makes them widely used in geochemical studies in terms of trace-elements, isotopes, ages and melt/mineral inclusions; in particular, zircons are persistent under most crustal conditions and can survive many secondary

  7. Differentiation of crusts and cores of the terrestrial planets: lessons for the early Earth

    International Nuclear Information System (INIS)

    Solomon, S.C.


    It now appears probable that all of the terrestrial planets underwent some form of global chemical differentiation to produce crusts, mantles, and cores of variable relative mass fractions. There is direct seismic evidence for a crust on the Moon, and indirect evidence for distinct crusts on Mars and Venus. Substantial portions of these crusts have been in place since the time that heavy bombardment of the inner solar system ceased approximately 4 Ga ago. There is direct evidence for a sizeable core on Mars, indirect evidence for one on Mercury, and bounds on a possible small core for the Moon. Core formation is an important heat source confined to times prior to 4 Ga ago for Mercury and the Earth, but was not closely linked to crustal formation on the Moon nor, apparently, on Mars. The tectonic and volcanic histories of the surfaces of the terrestrial planets Moon, Mars, and Mercury can be used, with simple thermal history models, to restrict the earliest chemical differentiation to be shallow (outer 200-400 km) for the first two bodies and much more extensive for Mercury. Extension of these models to an Earth-size planet leads to the prediction of a hot and vigorously convecting mantle with an easily deformable crust immediately following core formation, and of the gradual development of a lithosphere and of plates with some lateral rigidity in Late Archean-Proterzoic times. (Auth.)

  8. Analysis of energy and control efficiencies of fuzzy logic and artificial neural network technologies in the heating energy supply system responding to the changes of user demands

    International Nuclear Information System (INIS)

    Ahn, Jonghoon; Cho, Soolyeon; Chung, Dae Hun


    Highlights: • Advanced controllers are proposed to reduce control errors and energy consumption increases. • The FIS and ANN models are utilized to compare conventional thermostat on/off controller. • To provide appropriate thermal energy, the models control the amount of air and its temperature simultaneously. • Control errors, heat gains, and output signals are compared to define models’ effectiveness. • The ANN model shows the best result for space heating responding to intermittent thermal changes. - Abstract: This paper presents hybrid control approaches for heating air supply in response to changes in demand by using the Fuzzy Inference System (FIS) and Artificial Neural Network (ANN) fitting models. Since early 2000’s, some advanced computing and statistical tools were introduced to replace conventional control models in improving control and energy efficiency. Among the tools, the FIS and ANN algorithms were used to define complex interactions between inputs and outputs, and were able to facilitate control models to predict or evaluate precise thermal performance. This paper introduces the FIS and ANN control schemes for simultaneously controlling the amount of supply air and its temperature. Input and output data derived from the FIS results generate and validate the ANN model, and both models are compared to the typical thermostat on/off baseline control to evaluate conditions of supply air for a heating season. The differences between the set-point and actual room temperature and their sums indicate control efficiency, and the heat gains into a room and their sums define the energy consumption level. This paper concludes that the simultaneous control of mass and temperature maintains the desired room temperature in a highly efficient manner. Sensitive controls may have a disadvantage in terms of energy consumption, but the ANN controller can minimize energy consumption in comparison with simple thermostat on/off controller. The results also

  9. An analysis of the thermodynamic efficiency for exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB)

    International Nuclear Information System (INIS)

    Lee, Chang-Eon; Yu, Byeonghun; Lee, Seungro


    This study presents fundamental research on the development of a new boiler that is expected to have a higher efficiency and lower emissions than existing boilers. The thermodynamic efficiency of exhaust gas recirculation-condensed water recirculation-waste heat recovery condensing boilers (EGR-CWR-WHR CB) was calculated using thermodynamic analysis and was compared with other boilers. The results show the possibility of obtaining a high efficiency when the temperature of the exhaust gas is controlled within 50–60 °C because water in the exhaust gas is condensed within this temperature range. In addition, the enthalpy emitted by the exhaust gas for the new boiler is smaller because the amount of condensed water is increased by the high dew-point temperature and the low exhaust gas temperature. Thus, the new boiler can obtain a higher efficiency than can older boilers. The efficiency of the EGR-CWR-WHR CB proposed in this study is 93.91%, which is 7.04% higher than that of existing CB that is currently used frequently. - Highlights: • The study presents the development of a new boiler expected to have a high efficiency. • Thermodynamic efficiency of EGR-CWR-WHR condensing boiler was calculated. • Efficiency of EGR-CWR-WHR CB is 93.91%, which is 7.04% higher than existing CB

  10. Primary emissions and secondary aerosol production potential from woodstoves for residential heating: Influence of the stove technology and combustion efficiency (United States)

    Bertrand, Amelie; Stefenelli, Giulia; Bruns, Emily A.; Pieber, Simone M.; Temime-Roussel, Brice; Slowik, Jay G.; Prévôt, André S. H.; Wortham, Henri; El Haddad, Imad; Marchand, Nicolas


    To reduce the influence of biomass burning on air quality, consumers are encouraged to replace their old woodstove with new and cleaner appliances. While their primary emissions have been extensively investigated, the impact of atmospheric aging on these emissions, including secondary organic aerosol (SOA) formation, remains unknown. Here, using an atmospheric smog chamber, we aim at understanding the chemical nature and quantify the emission factors of the primary organic aerosols (POA) from three types of appliances for residential heating, and to assess the influence of aging thereon. Two, old and modern, logwood stoves and one pellet burner were operated under typical conditions. Emissions from an entire burning cycle (past the start-up operation) were injected, including the smoldering and flaming phases, resulting in highly variable emission factors. The stoves emitted a significant fraction of POA (up to 80%) and black carbon. After ageing, the total mass concentration of organic aerosol (OA) increased on average by a factor of 5. For the pellet stove, flaming conditions were maintained throughout the combustion. The aerosol was dominated by black carbon (over 90% of the primary emission) and amounted to the same quantity of primary aerosol emitted by the old logwood stove. However, after ageing, the OA mass was increased by a factor of 1.7 only, thus rendering OA emissions by the pellet stove almost negligible compared to the other two stoves tested. Therefore, the pellet stove was the most reliable and least polluting appliance out of the three stoves tested. The spectral signatures of the POA and aged emissions by a High Resolution - Time of Flight - Aerosol Mass Spectrometer (Electron Ionization (EI) at 70 eV) were also investigated. The m/z 44 (CO2+) and high molecular weight fragments (m/z 115 (C9H7+), 137 (C8H9O2+), 167 (C9H11O3+) and 181 (C9H9O4+, C14H13+)) correlate with the modified combustion efficiency (MCE) allowing us to discriminate further

  11. Norwegian crusted scabies: an unusual case presentation. (United States)

    Maghrabi, Michael M; Lum, Shireen; Joba, Ameha T; Meier, Molly J; Holmbeck, Ryan J; Kennedy, Kate


    Scabies is a contagious condition that is transmitted through direct contact with an infected person and has been frequently associated with institutional and healthcare-facility outbreaks. The subtype Norwegian crusted scabies can masquerade as other dermatologic diseases owing to the heavy plaque formation. Successful treatment has been documented in published reports, including oral ivermectin and topical permethrin. Few case studies documenting the treatment of Norwegian crusted scabies have reported the use of surgical debridement as an aid to topical and/or oral treatment when severe plaque formation has been noted. A nursing home patient was admitted to the hospital for severe plaque formation of both feet. A superficial biopsy was negative for both fungus and scabies because of the severity of the plaque formation on both feet. The patient underwent a surgical, diagnostic biopsy of both feet, leading to the diagnosis of Norwegian crusted scabies. A second surgical debridement was then performed to remove the extensive plaque formation and aid the oral ivermectin and topical permethrin treatment. The patient subsequently made a full recovery and was discharged back to the nursing home. At 2 and 6 months after treatment, the patient remained free of scabies infestation, and the surgical wound had healed uneventfully. The present case presentation has demonstrated that surgical debridement can be complementary to the standard topical and oral medications in the treatment of those with Norwegian crusted scabies infestation. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Dew formation and activity of biological crusts

    NARCIS (Netherlands)

    Veste, M.; Heusinkveld, B.G.; Berkowicz, S.M.; Breckle, S.W.; Littmann, T.; Jacobs, A.F.G.


    Biological soil crusts are prominent in many drylands and can be found in diverse parts of the globe including the Atacama desert, Chile, the Namib desert, Namibia, the Succulent-Karoo desert, South Africa, and the Negev desert, Israel. Because precipitation can be negligible in deserts ¿ the

  13. Eocene deep crust at Ama Drime, Tibet

    DEFF Research Database (Denmark)

    Kellett, Dawn; Cottle, John; Smit, Matthijs Arjen


    for burial of the lower Indian crust beneath Tibet reported from the central-eastern Himalaya. Granulite-facies overprinting followed at ca. 15–13 Ma, as indicated by U-Pb zircon ages. Unlike ultrahigh-pressure eclogites of the northwest Himalaya, the Ama Drime eclogites are not characteristic of rapid...

  14. Physics responsible for heating efficiency and self-controlled temperature rise of magnetic nanoparticles in magnetic hyperthermia therapy. (United States)

    Shaterabadi, Zhila; Nabiyouni, Gholamreza; Soleymani, Meysam


    Magnetic nanoparticles as heat-generating nanosources in hyperthermia treatment are still faced with many drawbacks for achieving sufficient clinical potential. In this context, increase in heating ability of magnetic nanoparticles in a biologically safe alternating magnetic field and also approach to a precise control on temperature rise are two challenging subjects so that a significant part of researchers' efforts has been devoted to them. Since a deep understanding of Physics concepts of heat generation by magnetic nanoparticles is essential to develop hyperthermia as a cancer treatment with non-adverse side effects, this review focuses on different mechanisms responsible for heat dissipation in a radio frequency magnetic field. Moreover, particular attention is given to ferrite-based nanoparticles because of their suitability in radio frequency magnetic fields. Also, the key role of Curie temperature in suppressing undesired temperature rise is highlighted. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Determination of adequate moisture content for efficient dry-heat viral inactivation in lyophilized factor VIII by loss on drying and by near infrared spectroscopy. (United States)

    Savage, M; Torres, J; Franks, L; Masecar, B; Hotta, J


    A requirement for a minimal threshold level of moisture in order for efficient virus inactivation to occur during dry heat treatment of freeze-dried coagulation factor concentrates is described. Techniques used to determine moisture content during heating were Loss on Drying and Karl Fischer. The Loss on Drying was suspected to have occasional errors as a result of sample preparation being influenced by interference from atmospheric moisture. Therefore, a non-invasive, non-destructive method for determination of residual moisture content using near infrared spectrometry (NIR) was developed for freeze-dried antihaemophilic factor (AHF). Calibration equations were determined against Loss on Drying and Karl Fischer assay methods and these equations evaluated for the predictive efficiency. Both Loss on Drying and NIR were used to evaluate the effect of moisture content on the efficiency of virus inactivation by dry heat at 80 degrees C. A minimum level of moisture of greater than 0.7%, as determined by Loss on Drying, was necessary for a virus reduction in the magnitude of 4 log10 for hepatitis A virus, porcine parvovirus and pseudorabies virus. Copyright 1998 The International Association of Biological Standardization

  16. Seismic structure of the Slave craton crust (United States)

    Barantseva, O.; Vinnik, L. P.; Farra, V.; van der Hilst, R. D.; Artemieva, I. M.; Montagner, J. P.


    We present P- and S-receiver functions for 20 stations along a 200-km-long NNW-SSE seismological profile across the Slave craton, and estimate the average crustal Vp/Vs ratio which is indicative of rock composition. We observe high Vp/Vs ratio ( 1.85-2.00) for the bulk crust and elevated Vp values at a depth range from 20-30 km to 40 km. High Vp values (>7.0 km/s) suggest mafic composition of the lower crust. In case of dry lower crustal rocks, the Vp/Vs ratio is expected to range from 1.6 to 1.8, which is lower than the observed values of 1.9-2.0. Laboratory studies show that Vp/Vs 1.9-2.0 can be explained by the presence of numerous cracks saturated with an incompressible fluid. Our results are at odds with the structure of the cratonic crust in many regions worldwide, and may suggest a unique geodynamic evolution of the Slave crust. Possible explanations for the observed crustal structure include the presence of an underplated mafic material, possibly related to intraplate magmatism or paleosubduction. Receiver functions are highly sensitive to the change of acoustic impedance and S-wave velocities, but do not resolve the internal seismic structure with a high precision. We extend our study of the crustal structure by using ambient noise tomography (ANT). We measure Rayleigh wave dispersion from Green's functions that are estimated from one-year noise cross-correlation (NCF). The phase velocity maps are inverted for 1D wave speed profiles which are then combined to form 2D and 3D models of the crust of the Slave Province. The combined results of RF analyses and ANT are interpreted in terms of crustal structure, composition, and evolution.

  17. Fecal excretion of Maillard reaction products and the gut microbiota composition of rats fed with bread crust or bread crumb. (United States)

    Helou, C; Anton, P M; Niquet-Léridon, C; Spatz, M; Tessier, F J; Gadonna-Widehem, P


    A comparison between the impacts of advanced (N ε -carboxymethyllysine - CML) and terminal (melanoidins) Maillard reaction products from bread on gut microbiota was carried out in this study. Gut microbiota composition as well as fecal excretion of CML from both bread crust and bread crumb, and of melanoidins from bread crust were assessed on a rodent model. Rats were fed with pellets supplemented or not with 13% of bread crust, bread crumb, a fiber-free bread crust model (glucose, starch and gluten heated together) or a fiber-free-melanoidin-free bread model (glucose-starch and gluten heated separately) for four weeks. These model systems were developed to limit the presence of wheat-native dietary fibers such as cellulose, hemicelluloses and lignin. CML and melanoidins in pellets and feces were evaluated by LC/MS-MS and HPLC/fluorescence respectively, and gut microbiota composition was determined by cultivation and molecular approaches. Diets supplemented with crumb or the fiber-free-melanoidin-free model contained respectively 17% and 64% less melanoidins than their respective controls. A higher excretion of melanoidins was observed for rats fed with crust or bread crust model compared to their controls, confirming that melanoidins are in contact with gut microbiota. No impact of diets was observed on Firmicutes, Bacteroidetes and lactic flora. A decrease of enterobacteria was only observed for rats fed with the diet supplemented with the fiber-free bread crust model. Moreover, a significant increase of bifidobacteria numbers in the presence of crust, crumb and both bread models was observed, showing that this bifidogenic effect of bread is not due to the presence of melanoidins or wheat-native dietary fibers.

  18. Residential space heating with wood burning stoves. Energy efficiency and indoor climate; Boligopvarmning ved braendefyring. Energieffektivitet og indeklima

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Ole Michael; Afshari, A.; Bergsoee, N.C.; Carvalho, R. [Miljoestyrelsen, Copenhagen (Denmark); Aalborg Univ.. Statens Byggeforskningsinstitut, Aalborg (Denmark))


    Two issues turn up concerning how to use wood-burning stoves in modern homes. The first is whether wood-burning stoves in future may still act as a genuine heat source, given that new and refurbished single-family houses retain the heat much better than older ones and therefore need less and less energy for space heating. The second issue is whether it will still be possible to use wood-burning stoves in modern houses where the air exchange is controlled by mechanical ventilation or possibly heat recovery. It is a question whether firing techniques can be developed that will work in airtight houses with mechanical ventilation and negative pressure, so that harmful particle emissions can be avoided. To illustrate the first issue, a field study was designed to look carefully at seven modern wood-burning stoves that were set up in six new houses and one older house and investigated, both in terms of firing and heat release. As a background for this part of the study, a heat balance calculation was made for each house. The question is, whether wood-burning stoves will also in the future have a role to play as a heating source. Modern houses grow ever tighter and only need to be supplied with a small quantity of heat. The new Danish Buildings Requirement, 2010 has resulted in a further reduction of 25 % of the energy demand, including the energy supply for heating. However, the new requirements imply that the heating season eventually become so short that a traditional central heating installation becomes superfluous. This means that by using the small amounts of wood cut in gardens and hedgerows of the neighbourhood, a wood-burning stove will, in principle, cover the heating demand. Therefore, the question is rather whether a wood-burning stove is manufactured that can successfully be adapted to new houses. As a consequence of this development, future stoves must be further scaled down in order to meet the heating demand of a modern low-energy house and the stoves must

  19. Positive geothermal anomalies in oceanic crust of Cretaceous age offshore Kamchatka

    Directory of Open Access Journals (Sweden)

    G. Delisle


    Full Text Available Heat flow measurements were carried out in 2009 offshore Kamchatka during the German-Russian joint-expedition KALMAR. An area with elevated heat flow in oceanic crust of Cretaceous age – detected ~30 yr ago in the course of several Russian heat flow surveys – was revisited. One previous interpretation postulated anomalous lithospheric conditions or a connection between a postulated mantle plume at great depth (>200 km as the source for the observed high heat flow. However, the positive heat flow anomaly – as our bathymetric data show – is closely associated with the fragmentation of the western flank of the Meiji Seamount into a horst and graben structure initiated during descent of the oceanic crust into the subduction zone offshore Kamchatka. This paper offers an alternative interpretation, which connects high heat flow primarily with natural convection of fluids in the fragmented rock mass and, as a potential additional factor, high rates of erosion, for which evidence is available from our collected bathymetric image. Given high erosion rates, warm rock material at depth rises to nearer the sea floor, where it cools and causes temporary elevated heat flow.

  20. Technical-Environmental-Economical Evaluation of the Implementation of a Highly Efficient District Heating System in China

    DEFF Research Database (Denmark)

    Zhang, Lipeng

    present value (NPV) to compare the annualized cost of using individual water heaters and flat stations. Environmental impacts were considered in terms of particle and CO2 emissions when various fuels are used to produce DHW. The results show that flat substations solutions are technically feasible...... was simulated using IDA Indoor Climate and Energy 4.6.2. The results show the hydraulically balanced heating system achieves 16% heat savings and 74% pump electricity savings. The second sub-hypothesis was that indoor comfort can be improved by activating the thermostatic sensors of TRV. At present, heating...... was developed that DHW production can be integrated into DH systems by using the flat stations concept. A multi-storey building with standard apartments was modelled to investigate the technical feasibility of this approach. On the premise of technical feasibility, an economic evaluation was made using net...

  1. Diffuse degassing through magmatic arc crust (Invited) (United States)

    Manning, C. E.; Ingebritsen, S.


    The crust of magmatic arcs plays an important role in the volatile cycle at convergent margins. The fluxes of subduction- and arc-related volatiles such as H2O, C, Cl, S are poorly known. It is commonly believed that gases emitted from volcanoes account nearly quantitatively for the volatiles that cross the Moho beneath the volcanic front. This volcanic degassing may occur during eruption, emission from summit fumaroles and hot springs, or more 'diffuse' delivery to volcano flanks. However, several observations suggest that volatiles also transit arc crust by even more diffuse pathways, which could account for significant volatile loss on long time and length scales. Active metamorphism of arc crust produces crustal-scale permeability that is sufficient to transport a large volume of subducted volatiles (Ingebritsen and Manning, 2002, PNAS, 99, 9113). Arc magmas may reach volatile saturation deeper than the maximum depths recorded by melt inclusions (e.g., Blundy et al., 2010, EPSL, 290, 289), and exhumed sections of magmatic arc crust typically record voluminous plutons reflecting magma crystallization and volatile loss at depths well below the volcanic edifice. At shallower depths, topographically driven meteoric groundwater systems can absorb magmatic volatiles and transport them laterally by tens of km (e.g., James et al., 1999, Geology, 27, 823; Evans et al., 2002, JVGR, 114, 291). Hydrothermal ore deposits formed at subvolcanic depths sequester vast amounts of volatiles, especially sulfur, that are only returned to the surface on the time scale of exhumation and/or erosion. Water-rich metamorphic fluids throughout the crust can readily carry exsolved volcanic gases because the solubilities of volatile bearing minerals such as calcite, anhydrite, and fluorite are quite high at elevated pressure and temperature (e.g., Newton and Manning, 2002, Am Min, 87, 1401; 2005, J Pet, 46, 701; Tropper and Manning, 2007, Chem Geol, 242, 299). Taken together, these

  2. Numerical simulations of thermo-compositional global convection with generation of proto-continental crust (United States)

    Rozel, A. B.; Golabek, G.; Gerya, T.; Jain, C.; Tackley, P. J.


    We study the creation of primordial continental crust (TTG rocks) employing fully self-consistent numerical models of thermo-chemical convection on a global scale at the Archean. We use realistic rheological parameters [1] in 2D spherical annulus geometry using the convection code StagYY [2] for a one billion years period. Starting from a pyrolytic composition and an initially warm core, our simulations first generate mafic crust and depleted mantle in the upper mantle. The basaltic material can be both erupted (cold) and/or intruded (warm) at the base of the crust following a predefined partitioning. At all times, water concentration is considered fully saturated in the top 10 km of the domain, and it simply advected with the deforming material elsewhere. We track the pressure-temperature conditions of the newly formed hydrated basalt and check if it matches the conditions necessary for the formation of proto-continental crust [3]. We systematically test the influence of volcanism (eruption, also called "heat pipe") and plutonism (intrusive magmatism) on the time-dependent geotherm in the lithosphere. We show that the "heat-pipe" model (assuming 100% eruption) suggested to be the main heat loss mechanism during the Archean epoch [4] is not able to produce continental crust since it forms a too cold lithosphere. We also systematically test various friction coefficients and show that an intrusion fraction higher than 60% (in agreement with [5]) combined with a friction coefficient larger than 0.1 produces the expected amount of the three main petrological TTG compositions previously reported [3]. This result seems robust as the amount of TTG rocks formed vary over orders of magnitude. A large eruption over intrusion ratio can result in up to 100 times less TTG felsic crust production than a case where plutonism dominates. This study represents a major step towards the production of self-consistent convection models able to generate the continental crust of the Earth

  3. Models for Interpreting Tungsten Isotope Anomalies in the Earth's Crust (United States)

    Humayun, M.; Brandon, A. D.; Righter, K.


    There have been several reports of positive tungsten isotope anomalies of about +15 ppm in rocks from Nuvvuagittuq (4.3 Ga), Isua (3.8 Ga) and Kostomuksha (2.8 Ga) that challenge models of differentiation and mantle mixing. Here, we employ constraints from experimental partitioning of W between metal and silicate, and from partial melting models, to evaluate the production and preservation of these W isotope anomalies in the Earth's earliest crust. We will also provide a revised interpretation of the Kostomuksha W isotope anomalies based on flow differentiation and metamorphism of komatiites. Two sets of models are produced. Model Set 1: Because D(metal-silicate) for W diminishes with increasing depth, the deep mantle has a higher W abundance, and a lower Hf/W ratio and consequently evolves a negative anomaly in W while the upper mantle evolves a complementary positive anomaly. Subsequent solid-state convection (4.55-2.8 Ga) mixes away the complementary W isotope anomalies to yield the modern mantle null value. This set of models predicts that the complementary negative anomalies in W should eventually be discovered in ancient magmatic rocks of deep mantle origin such as komatiites. Model Set 2: Tungsten is significantly more incompatible (like U, Th and Ba) than Hf, the latter being similar in compatibility to Sm. Our results show that extraction of low-degree partial melts (crust would result in negative anomalies in later plume lavas, while partitioning of W into an enriched "hidden reservoir" would not. Nd isotope anomalies indicate a melting event around 35-75 Ma after solar system formation, the upper end of which is consistent with our models of Hf/W fractionation, that also yield a depleted mantle composition consistent with DMM. Production of the anomalies is accompanied by the need to preserve the anomalies. We argue that the most effective means of preserving the W isotope anomalies is by crustal storage, and we hypothesize that W is efficiently recycled

  4. Characteristics and management options of crusting soils in a ...

    African Journals Online (AJOL)

    ... to control the crusting. The relationship between crust thickness and soil physical and chemical properties and management practices were assessed using stepwise regression analysis. Soil crusting was largely related to soil aggregation, infiltration, fine sand fraction, cotton monocropping and crop residue incorporation.

  5. Combining coal gasification, natural gas reforming, and external carbonless heat for efficient production of gasoline and diesel with CO2 capture and sequestration

    International Nuclear Information System (INIS)

    Salkuyeh, Yaser Khojasteh; Adams, Thomas A.


    Highlights: • Several systems are presented which convert NG, coal, and carbonless heat to fuel. • Using nuclear heat can reduce the direct fossil fuel consumption by up to 22%. • The use of CCS depended on the carbon tax: above $20-30/t is sufficient to use CCS. • CTL is only the most economical when the price of NG is more than $5 /MMBtu. • Compared to a traditional CTL plant, total CO 2 emission can be reduced up to 79%. - Abstract: In this paper, several novel polygeneration systems are presented which convert natural gas, coal, and a carbonless heat source such as high-temperature helium to gasoline and diesel. The carbonless heat source drives a natural gas reforming reaction to produce hydrogen rich syngas, which is mixed with coal-derived syngas to produce a syngas blend ideal for the Fischer–Tropsch reaction. Simulations and techno-economic analyses performed for 16 different process configurations under a variety of market conditions indicate significant economic and environmental benefits. Using a combination of coal, gas, and carbonless heat, it is possible to reduce CO 2 emissions (both direct and indirect) by 79% compared to a traditional coal-to-liquids process, and even achieve nearly zero CO 2 emissions when carbon capture and sequestration technology is employed. Using a carbonless heat source, the direct fossil fuel consumption can be reduced up to 22% and achieve a carbon efficiency up to 72%. Market considerations for this analysis include prices of coal, gas, high-temperature helium, gasoline, and CO 2 emission tax rates. The results indicate that coal-only systems are never the most economical choice, unless natural gas is more than 5 $/MMBtu

  6. Assessment of Efficiency of Regenerative Heating System of Feed Water for High Temperature Turbine Plant on Decentralized Power Engineering Facilities

    Directory of Open Access Journals (Sweden)

    Larionov Kirill


    Full Text Available The results of theoretical researches on efficiency of air heater use have been presented. The results of the research show the possibility of increase of energy efficiency of electrical power unit on electrical energy consumption by 2% at the initial temperature of steam 1073 K. The possibility of decrease of unit consumption of reference fuel by 4% has been stated.

  7. Assessment of Efficiency of Regenerative Heating System of Feed Water for High Temperature Turbine Plant on Decentralized Power Engineering Facilities


    Larionov, Kirill Borisovich; Gvozdyakov, Dmitry Vasilievich; Zenkov, Andrey Gennadievich; Zaytsev, Vladimir Valerianovich


    The results of theoretical researches on efficiency of air heater use have been presented. The results of the research show the possibility of increase of energy efficiency of electrical power unit on electrical energy consumption by 2% at the initial temperature of steam 1073 K. The possibility of decrease of unit consumption of reference fuel by 4% has been stated.

  8. Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-6 test data report: thermal hydraulic results, Rev. 0

    International Nuclear Information System (INIS)

    Lomperski, S.; Farmer, M.T.; Kilsdonk, D.; Aeschlimann, B.


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure? (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium (∼ φ 30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength is being addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus measures the fracture strength of the crust while it is either at room temperature or above, the latter state being achieved with a heating element placed below the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the sixth water ingression test, designated SSWICS-6. This test investigated

  9. Crusted Scabies in the Burned Patient

    DEFF Research Database (Denmark)

    Berg, Jais Oliver; Alsbjørn, Bjarne


    The objectives of this study were 1) to describe a case of crusted scabies (CS) in a burned patient, which was primarily undiagnosed and led to a nosocomial outbreak in the burn unit; 2) to analyze and discuss the difficulties in diagnosing and treating this subset of patients with burn injury......; and 3) to design a treatment strategy for future patients. Case analysis and literature review were performed. The index patient had undiagnosed crusted scabies (sive Scabies norvegica) with the ensuing mite hyperinfestation when admitted to the department with minor acute dermal burns. Conservative...... healing and autograft healing were impaired because of the condition. Successful treatment of the burns was only accomplished secondarily to scabicide treatment. An outbreak of scabies among staff members indirectly led to diagnosis. CS is ubiquitous, and diagnosis may be difficult. This is the first...

  10. Outer crust of nonaccreting cold neutron stars

    International Nuclear Information System (INIS)

    Ruester, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Juergen


    The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars

  11. Power, efficiency, ecological function and ecological coefficient of performance of an irreversible Dual-Miller cycle (DMC) with nonlinear variable specific heat ratio of working fluid (United States)

    Wu, Zhixiang; Chen, Lingen; Ge, Yanlin; Sun, Fengrui


    Finite time thermodynamic (FTT) theory is applied to perform performance analysis for an air-standard irreversible Dual-Miller cycle (DMC) based on the power output (P), thermal efficiency (η, ecological function (E) and ecological coefficient of performance (ECOP) criteria by considering nonlinear variable specific heat ratio, piston friction loss, heat transfer loss and other internal irreversible losses. Relationships between different performance characteristics are obtained via numerical calculations. Effects of pressure ratio and stroke length on each criterion are analyzed, and performance characteristics with different optimization objective are compared. The results show that pressure ratio has little influence on performance characteristics, but stroke length has great influence on performance characteristics. Moreover P, η, E and ECOP decrease with increasing stroke length, but when stroke length increases to a certain value, E is less than 0 whatever value of compression ratio takes. Choosing the E and ECOP as optimization objectives is more significant by comparing with other performance indexes.

  12. Cooling of Accretion-Heated Neutron Stars (United States)

    Wijnands, Rudy; Degenaar, Nathalie; Page, Dany


    We present a brief, observational review about the study of the cooling behaviour of accretion-heated neutron stars and the inferences about the neutron-star crust and core that have been obtained from these studies. Accretion of matter during outbursts can heat the crust out of thermal equilibrium with the core and after the accretion episodes are over, the crust will cool down until crust-core equilibrium is restored. We discuss the observed properties of the crust cooling sources and what has been learned about the physics of neutron-star crusts. We also briefly discuss those systems that have been observed long after their outbursts were over, i.e, during times when the crust and core are expected to be in thermal equilibrium. The surface temperature is then a direct probe for the core temperature. By comparing the expected temperatures based on estimates of the accretion history of the targets with the observed ones, the physics of neutron-star cores can be investigated. Finally, we discuss similar studies performed for strongly magnetized neutron stars in which the magnetic field might play an important role in the heating and cooling of the neutron stars.

  13. Living in cold homes after heating improvements: Evidence from Warm-Front, England's Home Energy Efficiency Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Critchley, Roger [Centre for Regional Economic and Social Research, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB (United Kingdom); Gilbertson, Jan [Centre for Regional Economic and Social Research, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB (United Kingdom)]. E-mail:; Grimsley, Michael [Centre for Regional Economic and Social Research, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB (United Kingdom); Green, Geoff [Centre for Regional Economic and Social Research, Sheffield Hallam University, City Campus, Howard Street, Sheffield, S1 1WB (United Kingdom)


    Objective: To investigate explanatory factors for persistent cold temperatures in homes which have received heating improvements. Design: Analysis of data from a national survey of dwellings and households (in England occupied by low-income residents) that had received heating improvements or repairs under the Warm Front Scheme. Methods: Over the winters of 2001-02 and 2002-03, householders recorded living room and main bedroom temperatures in a diary. Entries were examined for 888 households, which had received high level heating interventions. Two hundred and twenty-two households were identified as occupying cold homes, with mean bedroom temperature below 16 deg. C or mean living room temperatures below 18 deg. C. Binary logistic regression was used to model dwelling and household features and then occupants' behaviour and attitudes in the 'cold homes' sub-set compared with the remainder of the high intervention group. Seventy-nine supplementary, structured telephone interviews explored reasons given for lower temperatures. Using graphical and tabular methods, householders preferring cooler homes were distinguished from those who felt constrained in some way. Results: Cold homes predominate in pre-1930 properties where the householder remains dissatisfied with the heating system despite major improvements funded by Warm Front. Residents of cold homes are less likely to have long-standing illness or disability, but more likely to experience anxiety or depression. A small sample of telephone interviews reveals those preferring lower temperatures for health or other reasons, report less anxiety and depression than those with limited control over their home environment. Their 'thermal resistance' to higher temperatures challenges orthodox definitions of comfort and fuel poverty.

  14. Living in cold homes after heating improvements: Evidence from Warm-Front, England's Home Energy Efficiency Scheme

    International Nuclear Information System (INIS)

    Critchley, Roger; Gilbertson, Jan; Grimsley, Michael; Green, Geoff


    Objective: To investigate explanatory factors for persistent cold temperatures in homes which have received heating improvements. Design: Analysis of data from a national survey of dwellings and households (in England occupied by low-income residents) that had received heating improvements or repairs under the Warm Front Scheme. Methods: Over the winters of 2001-02 and 2002-03, householders recorded living room and main bedroom temperatures in a diary. Entries were examined for 888 households, which had received high level heating interventions. Two hundred and twenty-two households were identified as occupying cold homes, with mean bedroom temperature below 16 deg. C or mean living room temperatures below 18 deg. C. Binary logistic regression was used to model dwelling and household features and then occupants' behaviour and attitudes in the 'cold homes' sub-set compared with the remainder of the high intervention group. Seventy-nine supplementary, structured telephone interviews explored reasons given for lower temperatures. Using graphical and tabular methods, householders preferring cooler homes were distinguished from those who felt constrained in some way. Results: Cold homes predominate in pre-1930 properties where the householder remains dissatisfied with the heating system despite major improvements funded by Warm Front. Residents of cold homes are less likely to have long-standing illness or disability, but more likely to experience anxiety or depression. A small sample of telephone interviews reveals those preferring lower temperatures for health or other reasons, report less anxiety and depression than those with limited control over their home environment. Their 'thermal resistance' to higher temperatures challenges orthodox definitions of comfort and fuel poverty

  15. Time variability in Cenozoic reconstructions of mantle heat flow: plate tectonic cycles and implications for Earth's thermal evolution. (United States)

    Loyd, S J; Becker, T W; Conrad, C P; Lithgow-Bertelloni, C; Corsetti, F A


    The thermal evolution of Earth is governed by the rate of secular cooling and the amount of radiogenic heating. If mantle heat sources are known, surface heat flow at different times may be used to deduce the efficiency of convective cooling and ultimately the temporal character of plate tectonics. We estimate global heat flow from 65 Ma to the present using seafloor age reconstructions and a modified half-space cooling model, and we find that heat flow has decreased by approximately 0.15% every million years during the Cenozoic. By examining geometric trends in plate reconstructions since 120 Ma, we show that the reduction in heat flow is due to a decrease in the area of ridge-proximal oceanic crust. Even accounting for uncertainties in plate reconstructions, the rate of heat flow decrease is an order of magnitude faster than estimates based on smooth, parameterized cooling models. This implies that heat flow experiences short-term fluctuations associated with plate tectonic cyclicity. Continental separation does not appear to directly control convective wavelengths, but rather indirectly affects how oceanic plate systems adjust to accommodate global heat transport. Given that today's heat flow may be unusually low, secular cooling rates estimated from present-day values will tend to underestimate the average cooling rate. Thus, a mechanism that causes less efficient tectonic heat transport at higher temperatures may be required to prevent an unreasonably hot mantle in the recent past.

  16. Efficient reduction of graphene oxide film by low temperature heat treatment and its effect on electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xuebing; Chen, Zheng [Jingdezhen Ceramic Institute, Jingdezhen (China). Key Lab. of Inorganic Membrane; Yu, Yun [Shanghai Institute of Ceramics, Shanghai (China). Key Lab. of Inorganic Coating Materials; Zhang, Xiaozhen; Wang, Yongqing; Zhou, Jianer [Jingdezhen Ceramic Institute, Jingdezhen (China). Dept. of Materials Engineering


    Graphene-based conductive films have already attracted great attention due to their unique and outstanding physical properties. In this work, in order to develop a novel, effective method to produce these films with good electrical conductivity, a simple and green method is reported to rapidly and effectively reduce graphene oxide film using a low temperature heat treatment. The reduction of graphene oxide film is verified by XRD, FT-IR and Raman spectroscopy. Compared with graphene oxide film, the obtained reduced graphene oxide film has better electrical conductivity and its sheet resistance decreases from 25.3 kΩ x sq{sup -1} to 3.3 kΩ x sq{sup -1} after the heat treatment from 160 to 230 C. The mechanism of thermal reduction of the graphene oxide film mainly results from the removal of the oxygen-containing functional groups and the structural changes. All these results indicate that the low temperature heat treatment is a suitable and effective method for the reduction of graphene oxide film.

  17. Target-oriented obstacle analysis by PESTEL modeling of energy efficiency retrofit for existing residential buildings in China's northern heating region

    International Nuclear Information System (INIS)

    Shilei, Lv; Wu Yong


    According to the 'Comprehensive Work Program of Energy Efficiency and Emission Reduction' of the Chinese government, during the period of the '11th Five-Year Plan', 1.5x10 8 m 2 of existing residential buildings in China's northern heating region are to be retrofitted for energy efficiency. However, at present, this 'Energy Efficiency Retrofit for Existing Residential Buildings' (EERFERB) faces many obstacles. Under the current working and market system, both the central and local governments and the energy supply companies can not push on this work smoothly. Using both the results of the annual national special inspection of building energy efficiency and some case analyses, this paper examines the necessity for energy efficiency retrofit, along with the relationships among the various Political, Economic, Social, Technological, Environmental and Legal (PESTEL) factors affecting it. Furthermore, organizational, financial and technical support systems are explored to promote the development of retrofit. Finally, some primary principles to be followed toward the implementation of EERFERB are suggested.

  18. Target-oriented obstacle analysis by PESTEL modeling of energy efficiency retrofit for existing residential buildings in China's northern heating region

    Energy Technology Data Exchange (ETDEWEB)

    Shilei, Lv [School of Environment Science and Technology, Tianjin University, Tianjin 300072 (China); Yong, Wu [Department of Science and Technology, Ministry of Housing and Urban-Rural Development of the People' s Republic of China, Beijing 100835 (China)


    According to the 'Comprehensive Work Program of Energy Efficiency and Emission Reduction' of the Chinese government, during the period of the '11th Five-Year Plan', 1.5 x 10{sup 8} m{sup 2} of existing residential buildings in China's northern heating region are to be retrofitted for energy efficiency. However, at present, this 'Energy Efficiency Retrofit for Existing Residential Buildings' (EERFERB) faces many obstacles. Under the current working and market system, both the central and local governments and the energy supply companies can not push on this work smoothly. Using both the results of the annual national special inspection of building energy efficiency and some case analyses, this paper examines the necessity for energy efficiency retrofit, along with the relationships among the various Political, Economic, Social, Technological, Environmental and Legal (PESTEL) factors affecting it. Furthermore, organizational, financial and technical support systems are explored to promote the development of retrofit. Finally, some primary principles to be followed toward the implementation of EERFERB are suggested. (author)

  19. Survey report of year 2000 version. Feasibility study on energy efficiency/conservation, and environmental improvement of district heat and electricity supply station Radom City

    Energy Technology Data Exchange (ETDEWEB)



    In order to promote the COP3 joint implementation, discussions were given on the district heat and electricity supply station in Radom City in Poland. Power capacity utilized above a certain level will be generated by cogeneration power plants according to the annual heat supply load patterns, and insufficient capacity will be supplied from the existing hot water boilers during winter when thermal load is high. Daily load variation will be handled by installing auxiliary combustion facilities of 20% of the full capacity. The power plants will be of natural gas burning gas-turbine cogeneration plants, and hot water will be supplied from the modified waste heat boilers. The cogeneration power plants will be capable of taking care of 80% of the annual supply quantity of heat. The heat supply capacity will be 72 MWt including the auxiliary combustion, and the electric power generation capacity will be 35 MWe. Improvement in thermal efficiency to 80% or higher will reduce coal consumption, resulting in saving of 28,117 toe/year after subtracting the increase in natural gas consumption. Reduction in CO2 emission will also be as large as 206,000 tons/year, causing air pollutants to be also reduced. Assuming the facility cost of 4,336 billion yen to be taken care by the Japanese environmental yen loan, the Polish National Fund loan, and the independent fund of the city of Radom, the IRRON investment over the operation period of 30 years is considerably good at 10%. The investment can be recovered in nine years, and the cash flow will have no problems. (NEDO)

  20. Zircons reveal magma fluxes in the Earth's crust. (United States)

    Caricchi, Luca; Simpson, Guy; Schaltegger, Urs


    Magma fluxes regulate the planetary thermal budget, the growth of continents and the frequency and magnitude of volcanic eruptions, and play a part in the genesis and size of magmatic ore deposits. However, because a large fraction of the magma produced on the Earth does not erupt at the surface, determinations of magma fluxes are rare and this compromises our ability to establish a link between global heat transfer and large-scale geological processes. Here we show that age distributions of zircons, a mineral often present in crustal magmatic rocks, in combination with thermal modelling, provide an accurate means of retrieving magma fluxes. The characteristics of zircon age populations vary significantly and systematically as a function of the flux and total volume of magma accumulated in the Earth's crust. Our approach produces results that are consistent with independent determinations of magma fluxes and volumes of magmatic systems. Analysis of existing age population data sets using our method suggests that porphyry-type deposits, plutons and large eruptions each require magma input over different timescales at different characteristic average fluxes. We anticipate that more extensive and complete magma flux data sets will serve to clarify the control that the global heat flux exerts on the frequency of geological events such as volcanic eruptions, and to determine the main factors controlling the distribution of resources on our planet.

  1. Field Based Constraints on Reaction Rates in the Crust (United States)

    Baxter, E. F.


    Modern research in plate boundary processes involving metamorphism frequently employs complex physical models. Such models require some quantification (or assumption) of the rate at which metamorphic reactions, or chemical exchange, proceed in natural systems. Here, a compilation of available quantitative field-based constraints on high temperature reaction rates will be presented. These include quantifications based on isotopic exchange, porphyroblast and reaction corona growth models, geochronology, and textural analysis. Additionally, natural strain rates provide an important upper bound on simultaneous reaction rates by virtue of a direct mechanistic link between reaction and strain that applies in most situations within the deforming crust. These data show that reaction rates attending regional metamorphism are 4-7 orders of magnitude slower than most laboratory-based predictions. A general rate law for regional metamorphic reactions has been derived which best describes these field-based data: log10(Rnet) = .0029T-9.6±1, where Rnet is the net reaction rate in g/cm2/yr and T is temperature (C) (Baxter 2003, JGSL). Reaction rates attending contact metamorphism differ from laboratory-based predictions by less than 2 orders of magnitude, and are in closest agreement at higher temperatures. Regional metamorphic reaction rates may be limited by comparatively lesser (or transient) availability of aqueous fluid in the intergranular medium, slower heat input, and smaller deviations from equilibrium. Implications of slow natural metamorphic reaction rates may include a delay in the completion of metamorphic reactions which release (or take in) volatiles, and transform the mineralogy of the crust in dynamic plate boundary settings such as subduction zones.

  2. Surface formation, preservation, and history of low-porosity crusts at the WAIS Divide site, West Antarctica (United States)

    Fegyveresi, John M.; Alley, Richard B.; Muto, Atsuhiro; Orsi, Anaïs J.; Spencer, Matthew K.


    Observations at the West Antarctic Ice Sheet (WAIS) Divide site show that near-surface snow is strongly altered by weather-related processes such as strong winds and temperature fluctuations, producing features that are recognizable in the deep ice core. Prominent glazed surface crusts develop frequently at the site during summer seasons. Surface, snow pit, and ice core observations made in this study during summer field seasons from 2008-2009 to 2012-2013, supplemented by automated weather station (AWS) data with short- and longwave radiation sensors, revealed that such crusts formed during relatively low-wind, low-humidity, clear-sky periods with intense daytime sunshine. After formation, such glazed surfaces typically developed cracks in a polygonal pattern likely from thermal contraction at night. Cracking was commonest when several clear days occurred in succession and was generally followed by surface hoar growth; vapor escaping through the cracks during sunny days may have contributed to the high humidity that favored nighttime formation of surface hoar. Temperature and radiation observations show that daytime solar heating often warmed the near-surface snow above the air temperature, contributing to upward mass transfer, favoring crust formation from below, and then surface hoar formation. A simple surface energy calculation supports this observation. Subsequent examination of the WDC06A deep ice core revealed that crusts are preserved through the bubbly ice, and some occur in snow accumulated during winters, although not as commonly as in summertime deposits. Although no one has been on site to observe crust formation during winter, it may be favored by greater wintertime wind packing from stronger peak winds, high temperatures and steep temperature gradients from rapid midwinter warmings reaching as high as -15 °C, and perhaps longer intervals of surface stability. Time variations in crust occurrence in the core may provide paleoclimatic information

  3. Formation of fast-spreading lower oceanic crust as revealed by a new Mg-REE coupled geospeedometer (United States)

    Sun, Chenguang; Lissenberg, C. Johan


    A new geospeedometer is developed based on the differential closures of Mg and rare earth element (REE) bulk-diffusion between coexisting plagioclase and clinopyroxene. By coupling the two elements with distinct bulk closure temperatures, this speedometer can numerically solve the initial temperatures and cooling rates for individual rock samples. As the existing Mg-exchange thermometer was calibrated for a narrow temperature range and strongly relies on model-dependent silica activities, a new thermometer is developed using literature experimental data. When the bulk closure temperatures of Mg and REE are determined, respectively, using this new Mg-exchange thermometer and the existing REE-exchange thermometer, this speedometer can be implemented for a wide range of compositions, mineral modes, and grain sizes. Applications of this new geospeedometer to oceanic gabbros from the fast-spreading East Pacific Rise at Hess Deep reveal that the lower oceanic crust crystallized at temperatures of 998-1353 °C with cooling rates of 0.003-10.2 °C/yr. Stratigraphic variations of the cooling rates and crystallization temperatures support deep hydrothermal circulations and in situ solidification of various replenished magma bodies. Together with existing petrological, geochemical and geophysical evidence, results from this new speedometry suggest that the lower crust formation at fast-spreading mid-ocean ridges involves emplacement of primary mantle melts in the deep section of the crystal mush zone coupled with efficient heat removal by crustal-scale hydrothermal circulations. The replenished melts become chemically and thermally evolved, accumulate as small magma bodies at various depths, feed the shallow axial magma chamber, and may also escape from the mush zone to generate off-axial magma lenses.

  4. Simulation model for assessing the efficiency of a combined power installation based on a geothermal heat pump and a vacuum solar collector (United States)

    Vaysman, Ya I.; Surkov, AA; Surkova, Yu I.; Kychkin, AV


    The article is devoted to the use of renewable energy sources and the assessment of the feasibility of their use in the climatic conditions of the Western Urals. A simulation model that calculates the efficiency of a combined power installations (CPI) was (RES) developed. The CPI consists of the geothermal heat pump (GHP) and the vacuum solar collector (VCS) and is based on the research model. This model allows solving a wide range of problems in the field of energy and resource efficiency, and can be applied to other objects using RES. Based on the research recommendations for optimizing the management and the application of CPI were given. The optimization system will give a positive effect in the energy and resource consumption of low-rise residential buildings projects.

  5. Integration of Building energy and energy supply simulations for low-energy district heating supply to energy-efficient buildings

    DEFF Research Database (Denmark)

    Dalla Rosa, Alessandro


    The future will demand implementation of C02 neutral communities, the consequences being a far more complex design of the whole energy system, since the future energy infrastructures will be dynamic and climate responsive systems. Software able to work with such level of complexity is at present...... of the human behaviour regarding the building and link the results to the simulation program for DH networks. The results show that human behaviour can lead to 50% higher heating demand and 60% higher peak loads than expected according to reference values in standardized calculation of energy demand...

  6. Effect of pre-heating on the chemical oxidation efficiency: Implications for the PAH availability measurement in contaminated soils


    Biache, Coralie; Lorgeoux, Catherine; Andriatsihoarana, Sitraka; Colombano, Stéfan; Faure, Pierre


    International audience; Three chemical oxidation treatments (KMnO4, H2O2 and Fenton-like) were applied on three PAH-contaminated soils presenting different properties to determine the potential use of these treatments to evaluate the available PAH fraction. In order to increase the available fraction, a pre-heating (100 degrees C under N-2 for one week) was also applied on the samples prior oxidant addition. PAH and extractable organic matter contents were determined before and after treatmen...

  7. High Efficiency Integrated Space Conditioning, Water Heating and Air Distribution System for HUD-Code Manufactured Housing

    Energy Technology Data Exchange (ETDEWEB)

    Henry DeLima; Joe Akin; Joseph Pietsch


    Recognizing the need for new space conditioning and water heating systems for manufactured housing, DeLima Associates assembled a team to develop a space conditioning system that would enhance comfort conditions while also reducing energy usage at the systems level. The product, Comboflair® was defined as a result of a needs analysis of project sponsors and industry stakeholders. An integrated system would be developed that would combine a packaged airconditioning system with a small-duct, high-velocity air distribution system. In its basic configuration, the source for space heating would be a gas water heater. The complete system would be installed at the manufactured home factory and would require no site installation work at the homesite as is now required with conventional split-system air conditioners. Several prototypes were fabricated and tested before a field test unit was completed in October 2005. The Comboflair® system, complete with ductwork, was installed in a 1,984 square feet, double-wide manufactured home built by Palm Harbor Homes in Austin, TX. After the home was transported and installed at a Palm Harbor dealer lot in Austin, TX, a data acquisition system was installed for remote data collection. Over 60 parameters were continuously monitored and measurements were transmitted to a remote site every 15 minutes for performance analysis. The Comboflair® system was field tested from February 2006 until April 2007. The cooling system performed in accordance with the design specifications. The heating system initially could not provide the needed capacity at peak heating conditions until the water heater was replaced with a higher capacity standard water heater. All system comfort goals were then met. As a result of field testing, we have identified improvements to be made to specific components for incorporation into production models. The Comboflair® system will be manufactured by Unico, Inc. at their new production facility in St. Louis

  8. OECM MCCI Small-Scale Water Ingression and Crust Strength Tests (SSWICS) SSWICS-2 final data report, Rev. 0 February 12, 2003

    International Nuclear Information System (INIS)

    Lomperski, S.; Farmer, M.T.; Kilsdonk, D.; Aeschlimann, B.


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium (∼φ30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the second water ingression test, designated SSWICS-2. The test investigated the quench behavior of a 15 cm deep, fully

  9. OECD MMCI Small-Scale Water Ingression and Crust Strength tests (SSWICS) SSWICS-1 final data report, Rev. 1 February 10, 2003.; Report, Rev. 1

    International Nuclear Information System (INIS)

    Lomperski, S.; Farmer, M.T.; Kilsdonk, D.; Aeschlimann, B.


    The Melt Attack and Coolability Experiments (MACE) program at Argonne National Laboratory addressed the issue of the ability of water to cool and thermally stabilize a molten core/concrete interaction (MCCI) when the reactants are flooded from above. These tests provided data regarding the nature of corium interactions with concrete, the heat transfer rates from the melt to the overlying water pool, and the role of noncondensable gases in the mixing processes that contribute to melt quenching. However, due to the integral nature of these tests, several questions regarding the crust freezing behavior could not be adequately resolved. These questions include: (1) To what extent does water ingression into the crust increase the melt quench rate above the conduction-limited rate and how is this affected by melt composition and system pressure; and (2) What is the fracture strength of the corium crust when subjected to a thermal-mechanical load and how does it depend upon the melt composition? A series of separate-effects experiments are being conducted to address these issues. The first employs an apparatus designed to measure the quench rate of a pool of corium (∼φ30 cm; up to 20 cm deep). The main parameter to be varied in these quench tests is the melt composition since it is thought to have a critical influence on the crust cracking behavior which, in turn, alters quench rate. The issue of crust strength will be addressed with a second apparatus designed to mechanically load the crust produced by the quench tests. This apparatus will measure the fracture strength of the crust while under a thermal load created by a heating element beneath the crust. The two apparatuses used to measure the melt quench rate and crust strength are jointly referred to as SSWICS (Small-Scale Water Ingression and Crust Strength). This report describes results of the first water ingression test, designated SSWICS-1. The test investigated the quench behavior of a 15 cm deep, fully

  10. Preparation of regenerable granular carbon nanotubes by a simple heating-filtration method for efficient removal of typical pharmaceuticals (United States)

    Shan, Danna; Deng, Shubo; Zhao, Tianning; Yu, Gang; Winglee, Judith; Wiesner, Mark R.


    A simple and convenient method was used to prepare novel granular carbon nanotubes (CNTs) for enhanced adsorption of pharmaceuticals. By heating CNTs powder at 450 degree centigrade in air, followed by filtration, the obtained granular adsorbent exhibited high surface area and pore volume since the heating process produced some oxygen-containing functional groups on CNT surface, making CNTs more dispersible in the formation of granular cake. The porous granular CNTs not only had more available surfaces for adsorption but also were more easily separated from solution than pristine CNTs (p-CNTs) powder. This adsorbent exhibited relatively fast adsorption for carbamazepine (CBZ), tetracycline (TC) and diclofe- nac sodium (DS), and the maximum adsorption capacity on the granular CNTs was 369.5 μmol/g for CBZ, 284.2 μmol/g for TC and 203.1 μmol/g for DS according to the Langmuir fitting, increasing by 42.4%, 37.8% and 38.0% in comparison with the pristine CNTs powder. Moreover, the spent granular CNTs were successfully regenerated at 400 degree centigrade in air without decreasing the adsorption capacity in five regeneration cycles. The adsorbed CBZ and DS were completely degraded, while the adsorbed TC was partially oxidized and the residual was favorable for the subsequent adsorption. This research develops an easy method to prepare and regenerate granular CNT adsorbent for the enhanced removal of organic pollutants from water or wastewater.

  11. Designing an artificial neural network using radial basis function to model exergetic efficiency of nanofluids in mini double pipe heat exchanger (United States)

    Ghasemi, Nahid; Aghayari, Reza; Maddah, Heydar


    The present study aims at predicting and optimizing exergetic efficiency of TiO2-Al2O3/water nanofluid at different Reynolds numbers, volume fractions and twisted ratios using Artificial Neural Networks (ANN) and experimental data. Central Composite Design (CCD) and cascade Radial Basis Function (RBF) were used to display the significant levels of the analyzed factors on the exergetic efficiency. The size of TiO2-Al2O3/water nanocomposite was 20-70 nm. The parameters of ANN model were adapted by a training algorithm of radial basis function (RBF) with a wide range of experimental data set. Total mean square error and correlation coefficient were used to evaluate the results which the best result was obtained from double layer perceptron neural network with 30 neurons in which total Mean Square Error(MSE) and correlation coefficient (R2) were equal to 0.002 and 0.999, respectively. This indicated successful prediction of the network. Moreover, the proposed equation for predicting exergetic efficiency was extremely successful. According to the optimal curves, the optimum designing parameters of double pipe heat exchanger with inner twisted tape and nanofluid under the constrains of exergetic efficiency 0.937 are found to be Reynolds number 2500, twisted ratio 2.5 and volume fraction(v/v%) 0.05.

  12. A simplified fracture network model for studying the efficiency of a single well semi open loop heat exchanger in fractured crystalline rock (United States)

    de La Bernardie, Jérôme; de Dreuzy, Jean-Raynald; Bour, Olivier; Thierion, Charlotte; Ausseur, Jean-Yves; Lesuer, Hervé; Le Borgne, Tanguy


    Geothermal energy is a renewable energy source particularly attractive due to associated low greenhouse gas emission rates. Crystalline rocks are in general considered of poor interest for geothermal applications at shallow depths (energy storage at these shallow depths is still remaining very challenging because of the complexity of fractured media. The purpose of this study is to test the possibility of efficient thermal energy storage in shallow fractured rocks with a single well semi open loop heat exchanger (standing column well). For doing so, a simplified numerical model of fractured media is considered with few fractures. Here we present the different steps for building the model and for achieving the sensitivity analysis. First, an analytical and dimensional study on the equations has been achieved to highlight the main parameters that control the optimization of the system. In a second step, multiphysics software COMSOL was used to achieve numerical simulations in a very simplified model of fractured media. The objective was to test the efficiency of such a system to store and recover thermal energy depending on i) the few parameters controlling fracture network geometry (size and number of fractures) and ii) the frequency of cycles used to store and recover thermal energy. The results have then been compared to reference shallow geothermal systems already set up for porous media. Through this study, relationships between structure, heat exchanges and storage may be highlighted.

  13. High efficiency stratification of apple cultivar Ligol seed dormancy by phytohormones, heat shock and pulsed radio frequency. (United States)

    Grzesik, Mieczysław; Górnik, Krzysztof; Janas, Regina; Lewandowki, Mariusz; Romanowska-Duda, Zdzislawa; Duijn, Bert van


    The aim of the study was to improve the effect of stratification of apple "Ligol" seeds by application of selected compounds, phytohormones, and physical methods For this purpose the seeds were stratified at 3°C in distilled water or in the presence of potassium nitrate (KNO 3 ), ethephon (ET), carbon monoxide (CO), hydrogen peroxide (H 2 O 2 ), a mixture of KNO 3 , ET, CO, H 2 O 2 , gibberellins (GA 3 ), 6-benzylaminopurine (BAP), jasmonic acid (JA), salicylic acid (SA) and a mixture of SA, GA 3 , BAP, JA, nitric oxide (NO), hydrogen chloride (HCL). Arranged protocols included various durations and combinations of selected compounds and phytohormones as well as laser and red light, heat shock - 2h heat shock (45°C) and Pulsed Radio Frequency (PRF) were investigated by germination tests and the activity of selected enzymes, gas exchange and index of chlorophyll in leaves. The obtained results showed the possibility to shorten more effectively the time of the apple 'Ligol' dormancy removal by treatments of the stratified seeds at 3°C with different biological and physical methods Selected compounds and phytohormones acted collectively as a regulatory complex controlling the course of release from dormancy. Physical methods (PRF and heat shock) additionally contributed to dormancy breakage. Duration of phytohormones or compounds impacts during stratification should be prolonged to minimum 7days to assure more balanced conditions of the regulatory complex for the acceleration of dormancy a removal. The most beneficial results were obtained after seed stratification for 7days on filter paper moistened in KNO 3 +Etephon+CO+H 2 O 2 at 3°C, and then on filter paper moistened in phytohormones (GA 3 +BAP+JA) till the end of seed germination (3°C). The application of this protocol could be a very useful tool in a shortening the apple breeding cycle since the period of removing dormancy was reduced by 38days in comparison to stratified in water. PRF has also the additive

  14. Automation of heating system with heat pump


    Ferdin, Gašper


    Because of high prices of energy, we are upgrading our heating systems with newer, more fuel efficient heating devices. Each new device has its own control system, which operates independently from other devices in a heating system. With a relatively low investment costs in automation, we can group devices in one central control system and increase the energy efficiency of a heating system. In this project, we show how to connect an oil furnace, a sanitary heat pump, solar panels and a heat p...

  15. Improving the efficiency of heat supply systems on the basis of plants operating on organic Rankine cycle (United States)

    Solomin, I. N.; Daminov, A. Z.; Sadykov, R. A.


    Results of experimental and analytical studies of the plant main element - plant turbomachine (turbo-expander) operating on organic Rankine cycle were obtained for facilities of the heat supply systems of small-scale power generation. At simultaneous mathematical modeling and experimental studies it was found that the best working medium to be used in the turbomachines of these plants is Freon R245fa which has the most suitable calorimetric properties to be used in the cycle. The mathematical model of gas flow in the turbomachine was developed. The main engineering dependencies to calculate the optimal design parameters of the turbomachine were obtained. The engineering problems of providing the minimum axial size of the turbomachine impeller were solved and the main design elements were unified.

  16. Influence of heat treatment on cyclic fatigue and cutting efficiency of ProTaper Universal F2 instruments

    Directory of Open Access Journals (Sweden)

    Chih-Wen Chi


    Conclusion: Although 600°C treatment increased resistance to cyclic fatigue, it reduced the cutting efficiency of the files. The 400°C treatment maintained the cutting ability and prolonged the cyclic fatigue life of the files. Therefore, for clinical use of ProTaper Universal F2 files, 400°C pretreatment is a better choice than 600°C pretreatment.

  17. Non-cyanobacterial diazotrophs mediate dinitrogen fixation in biological soil crusts during early crust formation. (United States)

    Pepe-Ranney, Charles; Koechli, Chantal; Potrafka, Ruth; Andam, Cheryl; Eggleston, Erin; Garcia-Pichel, Ferran; Buckley, Daniel H


    Biological soil crusts (BSCs) are key components of ecosystem productivity in arid lands and they cover a substantial fraction of the terrestrial surface. In particular, BSC N2-fixation contributes significantly to the nitrogen (N) budget of arid land ecosystems. In mature crusts, N2-fixation is largely attributed to heterocystous cyanobacteria; however, early successional crusts possess few N2-fixing cyanobacteria and this suggests that microorganisms other than cyanobacteria mediate N2-fixation during the critical early stages of BSC development. DNA stable isotope probing with (15)N2 revealed that Clostridiaceae and Proteobacteria are the most common microorganisms that assimilate (15)N2 in early successional crusts. The Clostridiaceae identified are divergent from previously characterized isolates, though N2-fixation has previously been observed in this family. The Proteobacteria identified share >98.5% small subunit rRNA gene sequence identity with isolates from genera known to possess diazotrophs (for example, Pseudomonas, Klebsiella, Shigella and Ideonella). The low abundance of these heterotrophic diazotrophs in BSCs may explain why they have not been characterized previously. Diazotrophs have a critical role in BSC formation and characterization of these organisms represents a crucial step towards understanding how anthropogenic change will affect the formation and ecological function of BSCs in arid ecosystems.

  18. Surface coating for prevention of crust formation

    Energy Technology Data Exchange (ETDEWEB)

    Kronberg, J.W.


    A flexible surface coating which promotes the removal of deposits as they reach the surface by preventing adhesion and crust formation is disclosed. Flexible layers are attached to each side of a flexible mesh substrate comprising of a plurality of zones composed of one or more neighboring cells, each zone having a different compressibility than its adjacent zones. The substrate is composed of a mesh made of strands and open cells. The cells may be filled with foam. Studs or bearings may also be positioned in the cells to increase the variation in compressibility and thus the degree of flexing of the coating. Surface loading produces varying amounts of compression from point to point causing the coating to flex as deposits reach it, breaking up any hardening deposits before a continuous crust forms. Preferably one or more additional layers are also used, such as an outer layer of a non-stick material such as TEFLON, which may be pigmented, and an inner, adhesive layer to facilitate applying the coating to a surface. 5 figs.

  19. CHAMP Magnetic Anomalies of the Antarctic Crust (United States)

    Kim, Hyung Rae; Gaya-Pique, Luis R.; vonFrese, Ralph R. B.; Taylor, Patrick T.; Kim, Jeong Woo


    Regional magnetic signals of the crust are strongly masked by the core field and its secular variations components and hence difficult to isolate in the satellite measurements. In particular, the un-modeled effects of the strong auroral external fields and the complicated- behavior of the core field near the geomagnetic poles conspire to greatly reduce the crustal magnetic signal-to-noise ratio in the polar regions relative to the rest of the Earth. We can, however, use spectral correlation theory to filter the static lithospheric and core field components from the dynamic external field effects. To help isolate regional lithospheric from core field components, the correlations between CHAMP magnetic anomalies and the pseudo magnetic effects inferred from gravity-derived crustal thickness variations can also be exploited.. Employing these procedures, we processed the CHAMP magnetic observations for an improved magnetic anomaly map of the Antarctic crust. Relative to the much higher altitude Orsted and noisier Magsat observations, the CHAMP magnetic anomalies at 400 km altitude reveal new details on the effects of intracrustal magnetic features and crustal thickness variations of the Antarctic.

  20. Color characterization of Arctic Biological Soil Crusts (United States)

    Mele, Giacono; Gargiulo, Laura; Ventura, Stefano


    Global climate change makes large areas lacking the vegetation coverage continuously available to primary colonization by biological soil crusts (BSCs). This happens in many different environments, included high mountains and Polar Regions where new areas can become available due to glaciers retreat. Presence of BSCs leads to the stabilization of the substrate and to a possible development of protosoil, with an increase of fertility and resilience against erosion. Polar BSCs can exhibit many different proportions of cyanobacteria, algae, microfungi, lichens, and bryophytes which induce a large variability of the crust morphology and specific ecosystem functions. An effective and easy way for identifying the BSCs in the field would be very useful to rapidly recognize their development stage and help in understanding the overall impact of climate change in the delicate polar environments. Color analysis has long been applied as an easily measurable physical attribute of soil closely correlated with pedogenic processes and some soil functions. In this preliminary work we used RGB and CIE-L*a*b* color models in order to physically characterize fourteen different BSCs identified in Spitsbergen island of Svalbard archipelago in Arctic Ocean at 79° north latitude. We found that the "redness parameter "a*" of CIE-L*a*b* model was well correlated to the succession process of some BSCs at given geomorphology condition. Most of color parameters showed, moreover, a great potential to be correlated to photosynthetic activity and other ecosystem functions of BSCs.

  1. Kinetics of the crust thickness development of bread during baking. (United States)

    Soleimani Pour-Damanab, Alireza; Jafary, A; Rafiee, Sh


    The development of crust thickness of bread during baking is an important aspect of bread quality and shelf-life. Computer vision system was used for measuring the crust thickness via colorimetric properties of bread surface during baking process. Crust thickness had a negative and positive relationship with Lightness (L (*) ) and total color change (E (*) ) of bread surface, respectively. A linear negative trend was found between crust thickness and moisture ratio of bread samples. A simple mathematical model was proposed to predict the development of crust thickness of bread during baking, where the crust thickness was depended on moisture ratio that was described by the Page moisture losing model. The independent variables of the model were baking conditions, i.e. oven temperature and air velocity, and baking time. Consequently, the proposed model had well prediction ability, as the mean absolute estimation error of the model was 7.93 %.

  2. Visualization of Crust in Metallic Piping Through Real-Time Neutron Radiography Obtained with Low Intensity Thermal Neutron Flux

    Directory of Open Access Journals (Sweden)

    Leandro C. Luiz


    Full Text Available The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN/National Nuclear Energy Commission (CNEN reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.

  3. Visualization of crust in metallic piping through real-time neutron radiography obtained with low intensity thermal neutron flux

    Energy Technology Data Exchange (ETDEWEB)

    Luiz, Leandro C.; Crispim, Verginia R. [Nuclear Engineering Program, Federal University of Rio de Janeiro, Rio de Janeiro (Brazil); Ferreira, Francisco J. O. [National Nuclear Energy Commission, CNEN/IEN, Division Reactors, Rio de Janeiro (Brazil)


    The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.

  4. Visualization of crust in metallic piping through real-time neutron radiography obtained with low intensity thermal neutron flux

    International Nuclear Information System (INIS)

    Luiz, Leandro C.; Crispim, Verginia R.; Ferreira, Francisco J. O.


    The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows

  5. Crust behavior and erosion rate prediction of EPR sacrificial material impinged by core melt jet

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gen; Liu, Ming, E-mail:; Wang, Jinshi; Chong, Daotong; Yan, Junjie


    Highlights: • A numerical code was developed to analyze melt jet-concrete interaction in the frame of MPS method. • Crust and ablated concrete layer at UO{sub 2}-ZrO{sub 2} melt and concrete interface periodically developed and collapsed. • Concrete surface temperature fluctuated around a low temperature and ablation temperature. • Concrete erosion by Fe-Zr melt jet was significantly faster than that by UO{sub 2}-ZrO{sub 2} melt jet. - Abstract: Sacrificial material is a special ferro-siliceous concrete, designed in the ex-vessel core melt stabilization system of European Pressurized water Reactor (EPR). Given a localized break of RPV lower head, the melt directly impinges onto the dry concrete in form of compact jet. The concrete erosion behavior influences the failure of melt plug, and further affects melt spreading. In this study, a numerical code was developed in the frame of Moving Particle Semi-implicit (MPS) method, to analyze the crust behavior and erosion rate of sacrificial concrete, impinged by prototypic melt jet. In validation of numerical modeling, the time-dependent erosion depth and erosion configuration matched well with the experimental data. Sensitivity study of sacrificial concrete erosion indicates that the crust and ablated concrete layer presented at UO{sub 2}-ZrO{sub 2} melt and concrete interface, whereas no crust could be found in the interaction of Fe-Zr melt with concrete. The crust went through stabilization-fracture-reformation periodic process, accompanied with accumulating and collapsing of molten concrete layer. The concrete surface temperature fluctuated around a low temperature and ablation temperature. It increased as the concrete surface layer was heated to melting, and dropped down when the cold concrete was revealed. The erosion progression was fast in the conditions of small jet diameter and large concrete inclination angle, and it was significantly faster in the erosion by metallic melt jet than by oxidic melt jet.

  6. Flow of mantle fluids through the ductile lower crust: Heliumisotope trends

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, B. Mack; van Soest, Matthijs C.


    Heat and mass are injected into the shallow crust when mantle fluids are able to flow through the ductile lower crust. Minimum 3He/4He ratios in surface fluids from the northern Basin and Range province, western North America increase systematically from low, crustal values in the east to high, mantle values in the west, a regional trend that correlates with the rates of active crustal deformation. The highest ratios occur where the extension and shear strain rates are greatest. The correspondence of helium isotope ratios and active trans-tensional deformation indicates a deformation enhanced permeability and that mantle fluids can penetrate the ductile lithosphere in regions even where there is no significant magmatism. Superimposed on the regional trend are local, high-{sup 3}He/{sup 4}He anomalies signifying hidden magmatic activity and/or deep fluid production with locally enhanced permeability, identifying zones with high resource potential, particularly for geothermal energy development.

  7. Subduction of the primordial crust into the deep mantle

    Directory of Open Access Journals (Sweden)

    Hiroki Ichikawa


    Full Text Available The primordial crust on the Earth formed from the crystallization of the surface magma ocean during the Hadean. However, geological surveys have found no evidence of rocks dating back to more than 4 Ga on the Earth's surface, suggesting the Hadean crust was lost due to some processes. We investigated the subduction of one of the possible candidates for the primordial crust, anorthosite and KREEP crust similar to the Moon, which is also considered to have formed from the crystallization of the magma ocean. Similar to the present Earth, the subduction of primordial crust by subduction erosion is expected to be an effective way of eliminating primordial crust from the surface. In this study, the subduction rate of the primordial crust via subduction channels is evaluated by numerical simulations. The subduction channels are located between the subducting slab and the mantle wedge and are comprised of primordial crust materials supplied mainly by subduction erosion. We have found that primordial anorthosite and KREEP crust of up to ∼50 km thick at the Earth's surface was able to be conveyed to the deep mantle within 0.1-2 Gy by that mechanism.

  8. Biological Soil Crusts: Webs of Life in the Desert (United States)

    Belnap, Jayne


    Although the soil surface may look like dirt to you, it is full of living organisms that are a vital part of desert ecosystems. This veneer of life is called a biological soil crust. These crusts are found throughout the world, from hot deserts to polar regions. Crusts generally cover all soil spaces not occupied by green plants. In many areas, they comprise over 70% of the living ground cover and are key in reducing erosion, increasing water retention, and increasing soil fertility. In most dry regions, these crusts are dominated by cyanobacteria (previously called blue-green algae), which are one of the oldest known life forms. Communities of soil crusts also include lichens, mosses, microfungi, bacteria, and green algae. These living organisms and their by-products create a continuous crust on the soil surface. The general color, surface appearance, and amount of coverage of these crusts vary depending on climate and disturbance patterns. Immature crusts are generally flat and the color of the soil, which makes them difficult to distinguish from bare ground. Mature crusts, in contrast, are usually bumpy and dark-colored due to the presence of lichens, mosses, and high densities of cyanobacteria and other organisms.

  9. Energy efficiency façade design in high-rise apartment buildings using the calculation of solar heat transfer through windows with shading devices (United States)

    Ha, P. T. H.


    The architectural design orientation at the first design stage plays a key role and has a great impact on the energy consumption of a building throughout its life-cycle. To provide designers with a simple and useful tool in quantitatively determining and simply optimizing the energy efficiency of a building at the very first stage of conceptual design, a factor namely building envelope energy efficiency (Khqnl ) should be investigated and proposed. Heat transfer through windows and other glazed areas of mezzanine floors accounts for 86% of overall thermal transfer through building envelope, so the factor Khqnl of high-rise buildings largely depends on shading solutions. The author has established tables and charts to make reference to the values of Khqnl factor in certain high-rise apartment buildings in Hanoi calculated with a software program subject to various inputs including: types and sizes of shading devices, building orientations and at different points of time to be respectively analyzed. It is possible and easier for architects to refer to these tables and charts in façade design for a higher level of energy efficiency.

  10. Thermal effects of late accretion to the crust and mantle of Mercury (United States)

    Mojzsis, S. J.; Abramov, O.; Frank, E. A.; Brasser, R.


    Impact bombardment on Mercury in the solar system's late accretion phase (ca. 4.4-3.8 Ga) caused considerable mechanical, chemical and thermal reworking of its silicate reservoirs (crust and mantle). Depending on the frequency, size and velocity of such impactors, effects included regional- and global-scale crustal melting, and thermal perturbations of the mercurian mantle. We use a 3D transient heating model to test the effects of two bombardment scenarios on early (pre-Tolstojan) Mercury's mantle and crust. Results show that rare impacts by the largest (≳100 km diameter) bodies deliver sufficient heat to the shallow mercurian mantle producing high-temperature ultra-magnesian (komatiitic s.s.) melts. Impact heating leading to effusive (flood) volcanism can account for the eponymous "high-magnesium region" (HMR) observed during the MErcury Surface, Space Environment, GEochemistry Ranging (MESSENGER) mission. We find that late accretion to Mercury induced volumetrically significant crustal melting (≤58 vol.%), mantle heating and melt production, which, combined with extensive resurfacing (≤100%), also explains why its oldest cratering record was effectively erased, consistent with crater-counting statistics.

  11. Direct fired heat exchanger (United States)

    Reimann, Robert C.; Root, Richard A.


    A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

  12. Crusting susceptibility in some allic Colombian soils

    International Nuclear Information System (INIS)

    Arias, Dora M; Madero E E; Amezquita E


    Many lab methods were used: dry and water soil aggregates stability, instability index and erosion index and their results were related with soil characteristics like texture, Fe and Al oxides and organic matter. Soil samples collected within 0-2.5 and 2.5-5 cm of the soil surface came from terrains with many kinds of both forest and savanna intervened systems. Those results were analyzed like a completely randomized designed. It was found that significative changes in oxides content could increase soil-crusting susceptibility unless soil humus was up to was up to 4%. In this sense, pastures or its rotation with rice and leguminous offer a best alternative for intervening these natural systems. Intensive land husbandry or monocultures with low stubble soil incorporation caused an increase in physical instability at the top of soil. Dry soil stability test and instability index were most adequate for these soils

  13. Moho vs crust-mantle boundary: Evolution of an idea (United States)

    O'Reilly, Suzanne Y.; Griffin, W. L.


    The concept that the Mohorovicic Discontinuity (Moho) does not necessarily coincide with the base of the continental crust as defined by rock-type compositions was introduced in the early 1980s. This had an important impact on understanding the nature of the crust-mantle boundary using information from seismology and from deep-seated samples brought to the surface as xenoliths in magmas, or as tectonic terranes. The use of empirically-constrained P-T estimates to plot the locus of temperature vs depth for xenoliths defined a variety of geotherms depending on tectonic environment. The xenolith geotherms provided a framework for constructing lithological sections through the deep lithosphere, and revealed that the crust-mantle boundary in off-craton regions commonly is transitional over a depth range of about 5-20 km. Early seismic-reflection data showed common layering near the Moho, correlating with the petrological observation of multiple episodes of basaltic intrusion around the crust-mantle boundary. Developments in seismology, petrophysics and experimental petrology have refined interpretation of lithospheric domains. The expansion of in situ geochronology (especially zircon U-Pb ages and Hf-isotopes; Os isotopes of mantle sulfides) has defined tectonic events that affected whole crust-mantle sections, and revealed that the crust-mantle boundary can change in depth through time. However, the nature of the crust-mantle boundary in cratonic regions remains enigmatic, mainly due to lack of key xenoliths or exposed sections. The observation that the Moho may lie significantly deeper than the crust-mantle boundary has important implications for modeling the volume of the crust. Mapping the crust using seismic techniques alone, without consideration of the petrological problems, may lead to an overestimation of crustal thickness by 15-30%. This will propagate to large uncertainties in the calculation of elemental mass balances relevant to crust-formation processes

  14. Heating efficiency and correlation between the structural and magnetic properties of oleic acid coated MnFe2O4 nanoparticles for magnetic hyperthermia application (United States)

    Raland, R. D.; Saikia, D.; Borgohain, C.; Borah, J. P.


    In pursuit of developing magnetic nanoparticles with optimal heat dissipation capabilities, we have successfully synthesized manganese ferrite (MnFe2O4) nanoparticles coated with various concentrations of oleic acid (OA) via co-precipitation. We found that the particle size decreases gradually with increasing OA concentration (35 nm for 0% OA  →  30 nm for 5% OA  →  27 nm for 7% OA  →  20 nm for 9% OA), which was confirmed by the x-ray diffractogram, Williamson-Hall plot and transmission electron micrograph. We also observe a decrease in lattice parameter, and interestingly, change in the shape of MnFe2O4 nanoparticles to quasi-cubic with the increase of OA concentration. These structural changes also manifest in the cation re-distribution, bond length and angle between the octahedral and tetrahedral sites. The magnetic properties are determined by vibrational sample magnetometry (VSM), which shows an increase in the saturation magnetization (M s) from 26 emu g-1 to 38 emu g-1 with almost negligible coercivity, indicating the superparamagnetic nature of the nanoparticles. Finally, the efficiency of induction heating is measured by its specific absorption rate (SAR) and intrinsic loss power (ILP), whose value varies as a function of saturation magnetization, engendered by the changes in the structural motifs of the MnFe2O4 nanoparticles under the influence of OA coating and their concentrations. This study demonstrates the quantitative link between the size, shape and magnetic anisotropy, which are intimately entwined with the heating performance of the nanoparticle.

  15. A novel energy-efficient pyrolysis process: self-pyrolysis of oil shale triggered by topochemical heat in a horizontal fixed bed. (United States)

    Sun, You-Hong; Bai, Feng-Tian; Lü, Xiao-Shu; Li, Qiang; Liu, Yu-Min; Guo, Ming-Yi; Guo, Wei; Liu, Bao-Chang


    This paper proposes a novel energy-efficient oil shale pyrolysis process triggered by a topochemical reaction that can be applied in horizontal oil shale formations. The process starts by feeding preheated air to oil shale to initiate a topochemical reaction and the onset of self-pyrolysis. As the temperature in the virgin oil shale increases (to 250-300°C), the hot air can be replaced by ambient-temperature air, allowing heat to be released by internal topochemical reactions to complete the pyrolysis. The propagation of fronts formed in this process, the temperature evolution, and the reaction mechanism of oil shale pyrolysis in porous media are discussed and compared with those in a traditional oxygen-free process. The results show that the self-pyrolysis of oil shale can be achieved with the proposed method without any need for external heat. The results also verify that fractured oil shale may be more suitable for underground retorting. Moreover, the gas and liquid products from this method were characterised, and a highly instrumented experimental device designed specifically for this process is described. This study can serve as a reference for new ideas on oil shale in situ pyrolysis processes.

  16. A Novel Energy-Efficient Pyrolysis Process: Self-pyrolysis of Oil Shale Triggered by Topochemical Heat in a Horizontal Fixed Bed (United States)

    Sun, You-Hong; Bai, Feng-Tian; Lü, Xiao-Shu; Li, Qiang; Liu, Yu-Min; Guo, Ming-Yi; Guo, Wei; Liu, Bao-Chang


    This paper proposes a novel energy-efficient oil shale pyrolysis process triggered by a topochemical reaction that can be applied in horizontal oil shale formations. The process starts by feeding preheated air to oil shale to initiate a topochemical reaction and the onset of self-pyrolysis. As the temperature in the virgin oil shale increases (to 250-300°C), the hot air can be replaced by ambient-temperature air, allowing heat to be released by internal topochemical reactions to complete the pyrolysis. The propagation of fronts formed in this process, the temperature evolution, and the reaction mechanism of oil shale pyrolysis in porous media are discussed and compared with those in a traditional oxygen-free process. The results show that the self-pyrolysis of oil shale can be achieved with the proposed method without any need for external heat. The results also verify that fractured oil shale may be more suitable for underground retorting. Moreover, the gas and liquid products from this method were characterised, and a highly instrumented experimental device designed specifically for this process is described. This study can serve as a reference for new ideas on oil shale in situ pyrolysis processes.

  17. Turnkey Heating, Ventilating, and Air Conditioning and Lighting Retrofit Solution Combining Energy Efficiency and Demand Response Benefits

    Energy Technology Data Exchange (ETDEWEB)

    Doebber, Ian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Deru, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States); Trenbath, Kim [National Renewable Energy Lab. (NREL), Golden, CO (United States)


    NREL worked with the Bonneville Power Administration's Technology Innovation Office to demonstrate a turnkey, retrofit technology that combines demand response (DR) and energy efficiency (EE) benefits for HVAC and lighting in retail buildings. As a secondary benefit, we also controlled various plug loads and electric hot water heaters (EHWH). The technology demonstrated was Transformative Wave's eIQ Building Management System (BMS) automatically responding to DR signals. The BMS controlled the HVAC rooftop units (RTU) using the CATALYST retrofit solution also developed by Transformative Wave. The non-HVAC loads were controlled using both hardwired and ZigBee wireless communication. The wireless controllers, manufactured by Autani, were used when the building's electrical layout was too disorganized to leverage less expensive hardwired control. The six demonstration locations are within the Seattle metro area. Based on the assets curtailed by the BMS at each location, we projected the DR resource. We were targeting a 1.7 W/ft2 shed for the summer Day-Ahead events and a 0.7 W/ft2 shed for the winter events. While summarized in Table ES-1, only one summer DR event was conducted at Casino #2.

  18. Variability in Rock Thermal Properties in the Late Archean Crust of the Kapuskasing Structural Zone and Implications for its Thermal Structure and Metamorphic History. (United States)

    Merriman, J. D.; Whittington, A. G.; Hofmeister, A. M.


    The thermal properties of rocks such as internal heat production and thermal diffusivity (α) play a key role in determining the thermal structure of the lithosphere, and consequently, the rates and styles of metamorphism within the crust. Over the last decade, measurements of α using the method laser flash analysis have shown the ability of a rock to conduct heat can vary by as much as a factor of 5 between common rock types, and decrease by up to a factor of 10 for the same rock between 25-1000°C. Here we present a preliminary model for the variability in rock throughout the crust based on measurements of the α of a suite of 100 samples from late Archean crust exposed in and around the Kapuskasing Structural Zone in Ontario, Canada. Preliminary results suggest that α is controlled primarily by mineralogy, and can vary not only between different rock types as described above, but also within the same rock by a factor of 1.5 (or more). Thermal diffusivity results were combined with heat producing element concentrations measured with ICP-MS to create a thermal model of the Kapuskasing Structural Zone prior its uplift and exposure. To provide additional constraints for P-T conditions within the pre-uplift KSZ crust, a combination of trace-element and pseudosection thermobarometry was used to estimate metamorphic temperatures during an extended period of crustal stability at the end of the Archean. Preliminary results were compared to finite-difference numerical models of the steady-state geothermal gradient using heat production back-calculated to 2.6 Ga. Results suggest a minimum thickness of the continental lithosphere during the late Archean of at least 150 km. To test the response of the crust to the effects of large thermal events such as pluton emplacement, we also performed time-dependent models of the thermal structure of the pre-uplift KSZ crust. These models suggest that heat from thermal events in the upper and middle crust result in a more insulating

  19. Soil Characteristics of Crusted outside and Subcanopy Areas of four ...

    African Journals Online (AJOL)

    The results on compaction, salinity, pH, water holding capacity, respiration and organic carbon supported the model. The crust:shrub ratio is crucial for the functioning and sustained productivity of the system. Keywords: Soil characteristics; shrub subcanopy; crust; sink-source, Negev desert [IJARD Vol.3 2002: 162-170] ...

  20. Increasing cotton stand establishment in soils prone to soil crusting (United States)

    Many factors can contribute to poor cotton stand establishment, and cotton is notorious for its weak seedling vigor. Soil crusting can be a major factor hindering cotton seedling emergence in many of the cotton production regions of the US and the world. Crusting is mainly an issue in silty soils ...

  1. Rainfall pattern effects on crusting, infiltration and erodibility in some ...

    African Journals Online (AJOL)

    Rainfall characteristics affect crust formation, infiltration rate and erosion depending on intrinsic soil properties such as texture and mineralogy. The current study investigated the effects of rainfall pattern on crust strength, steady state infiltration rate (SSIR) and erosion in soils with various texture and minerals. Soil samples ...

  2. Compositional variation and genesis of ferromanganese crusts of ...

    Indian Academy of Sciences (India)

    The Ce-content is the highest reported so far (up to 3763 ppm, average ∼2250 ppm) for global ocean seamount Fe-Mn crusts. In spite of general similarity in the range of major, minor, and strictly trivalent rare earth element composition, the dissimilarity between the present Fe-Mn crusts and the Pacific seamount Fe-Mn ...

  3. Reduction of acrylamide content in bread crust by starch coating. (United States)

    Liu, Jie; Liu, Xiaojie; Man, Yong; Liu, Yawei


    A technique of starch coating to reduce acrylamide content in bread crust was proposed. Bread was prepared in accordance with a conventional procedure and corn or potato starch coating was brushed on the surface of the fermented dough prior to baking. Corn starch coating caused a decrease in acrylamide of 66.7% and 77.1% for the outer and inner crust, respectively. The decrease caused by the potato starch coating was 68.4% and 77.4%, respectively. Starch coating reduced asparagine content significantly (43.4-82.9%; P bread crust were a result of starch coating, which effectively shortened the time span (4-8 min) over which acrylamide could form and accumulate. The present study demonstrates that starch coating could be a simple, effective and practical application for reducing acrylamide levels in bread crust without changing the texture and crust color of bread. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. FeCo-Anchored Reduced Graphene Oxide Framework-Based Soft Composites Containing Carbon Nanotubes as Highly Efficient Microwave Absorbers with Excellent Heat Dissipation Ability. (United States)

    Arief, Injamamul; Biswas, Sourav; Bose, Suryasarathi


    Conducting polymer composites containing ferromagnetic grafted-graphene derivatives are already appreciated for their lightweight, flexibility, and cost effectiveness in terms of microwave absorption. To further leverage the said properties of this wonder material, we propose a highly efficient replacement by blending conducting multiwall carbon nanotube (MWCNT) and FeCo anchored covalent cross-linked reduced graphene oxide (rGO) with poly(vinylidene fluoride) (PVDF). Interconnected conducting network of MWCNTs introduces higher electrical conductivity in the blend which is essential for microwave absorption. FeCo-anchored porous interconnected rGO framework was designed via solvent-mediated in situ coreduction in the presence of Fe(II) and Co(II) precursors. Resulting cross-linked-rGO/FeCo displays fascinating coexistence of ferromagnetism and conducting-dielectric behavior, while largely preserving the robust 3D porous interconnected structure. Coupled with conducting MWCNTs, diamine cross-linked rGO/FeCo in a soft polymer matrix yields remarkably high total shielding effectiveness (SE T ) of -41.2 dB at 12 GHz, for a meager 10 wt % filler content. In addition, the composite materials display efficient heat dissipation abilities in conjunction with the trend in their thermal conductivities. This new-age microwave-absorbing material, powered by multifunctionality and tunable magnetodielectric properties, henceforth offers an amendable, cost-effective replacement to the existing solutions.

  5. Coordination of Heat Pumps, Electric Vehicles and AGC for Efficient LFC in a Smart Hybrid Power System via SCA-Based Optimized FOPID Controllers

    Directory of Open Access Journals (Sweden)

    Rahmat Khezri


    Full Text Available Due to the high price of fossil fuels, the increased carbon footprint in conventional generation units and the intermittent functionality of renewable units, alternative sources must contribute to the load frequency control (LFC of the power system. To tackle the challenge, dealing with controllable loads, the ongoing study aims at efficient LFC in smart hybrid power systems. To achieve this goal, heat pumps (HPs and electric vehicles (EVs are selected as the most effective controllable loads to contribute to the LFC issue. In this regard, the EVs can be controlled in a bidirectional manner as known charging and discharging states under a smart structure. In addition, regarding the HPs, the power consumption is controllable. As the main task, this paper proposes a fractional order proportional integral differential (FOPID controller for coordinated control of power consumption in HPs, the discharging state in EVs and automatic generation control (AGC. The parameters of the FOPID controllers are optimized simultaneously by the sine cosine algorithm (SCA, which is a new method for optimization problems. In the sequel, four scenarios, including step and random load changes, aggregated intermittent generated power from wind turbines, a random load change scenario and a sensitivity analysis scenario, are selected to demonstrate the efficiency of the proposed SCA-based FOPID controllers in a hybrid two-area power system.

  6. Generation of continental crust in intra-oceanic arcs (United States)

    Gazel, E.; Hayes, J. L.; Kelemen, P. B.; Everson, E. D.; Holbrook, W. S.; Vance, E.


    The origin of continental crust is still an unsolved mystery in the evolution of our planet. Although the best candidates to produce juvenile continental crust are intra-oceanic arcs these systems are dominated by basaltic lavas, and when silicic magmas are produced, the incompatible-element compositions are generally too depleted to be a good match for continental crust estimates. Others, such as the W. Aleutians, are dominated by andesitic melts with trace element compositions similar to average continental crust. In order to evaluate which intra-oceanic arcs produced modern continental crust, we developed a geochemical continental index (CI) through a statistical analysis that compared all available data from modern intra-oceanic arcs with global estimates of continental crust. Our results suggest that magmas from Costa Rica (tracks. Iwo-Jima and Vanuatu are in a similar tectonic scenario with subducting intraplate seamounts. Melts from the subducting oceanic crust are thought to significantly control the geochemical signature in the W. Aleutians and Panama. In the L. Antilles and E. Aleutians the continental signature may reflect recycling of a component derived from subducting continental sediments. Most of Izu-Bonin, Marianas, S. Scotia and Tonga arcs with a CI >100 have the least continent-like geochemical signatures. In these arcs the subducting plate is old (>100 Ma), not overprinted by enriched intraplate volcanism and the geochemistry may be dominated by slab-derived, aqueous fluids. We also found a strong correlation between the CI and average crustal P-wave velocity, validating the geochemical index with the available seismic data for intra-oceanic arcs. In conclusion, the production of young continental crust with compositions similar to Archean continental crust is an unusual process, limited to locations where there are especially voluminous partial melts of oceanic crust.

  7. Heat pumps in district heating networks

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    In the current Danish energy system, the majority of electricity and heat is produced in combined heat and power plants. With increasing shares of intermittent renewable power production, it becomes a challenging task to match power and heat production, as heat demand and production capacity...... constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... are calculated using an energy system model which includes power plants, heat pumps and district heating consumption profiles. The model is developed with focus on accurate representation of the performance of the units in different locations and operating modes. The model can assist in investment decisions...

  8. Heat Roadmap Europe 1

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg


    Heat Roadmap Europe (Pre-study 1) investigates the role of district heating in the EU27 energy system by mapping local conditions across Europe, identifying the potential for district heating expansion, and subsequently simulating the potential resource in an hourly model of the EU27 energy system....... In 2010, approximately 12% of the space heating demand in Europe is met by district heating, but in this study four alternative scenarios are considered for the EU27 energy system: 1. 2010 with 30% district heating 2. 2010 with 50% district heating 3. 2030 with 30% district heating 4. 2050 with 50......% district heating These scenarios are investigated in two steps. Firstly, district heating replaces individual boilers by converting condensing power plants to combined heat and power plants (CHP) to illustrate how district heating improves the overall efficiency of the energy system. In the second step...

  9. Hydrogenetic Ferromanganese Crusts of the California Continental Margin (United States)

    Conrad, Tracey A.

    Hydrogenetic Ferromanganese (Fe-Mn) crusts grow from seawater and in doing so sequester elements of economic interest and serve as archives of past seawater chemistry. Ferromanganese crusts have been extensively studied in open-ocean environments. However, few studies have examined continent-proximal Fe-Mn crusts especially from the northeast Pacific. This thesis addresses Fe-Mn crusts within the northeast Pacific California continental margin (CCM), which is a dynamic geological and oceanographic environment. In the first of three studies, I analyzed the chemical and mineralogical composition of Fe-Mn crusts and show that continental-proximal processes greatly influence the chemistry and mineralogy of CCM Fe-Mn crusts. When compared to global open-ocean Fe-Mn crusts, CCM crusts have higher concentrations of iron, silica, and thorium with lower concentrations of many elements of economic interest including manganese, cobalt, and tellurium, among other elements. The mineralogy of CCM Fe-Mn crusts is also unique with more birnessite and todorokite present than found in open-ocean samples. Unlike open-ocean Fe-Mn crusts, carbonate-