WorldWideScience

Sample records for on-site combined heat

  1. Heat integration and analysis of decarbonised IGCC sites

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.S.; Lopez, Y.; Campbell, G.M.; Sadhukhan, J. [University of Manchester, Manchester (United Kingdom). School of Chemical Engineering & Analytical Science

    2010-02-15

    Integrated gasification combined cycle (IGCC) power generation systems have become of interest due to their high combined heat and power (CHP) generation efficiency and flexibility to include carbon capture and storage (CCS) in order to reduce CO{sub 2} emissions. However, IGCC's biggest challenge is its high cost of energy production. In this study, decarbonised coal IGCC sites integrated with CCS have been investigated for heat integration and economic value analyses. It is envisaged that the high energy production cost of an IGCC site can be offset by maximising site-wide heat recovery and thereby improving the cost of electricity (COE) of CHP generation. Strategies for designing high efficiency CHP networks have been proposed based on thermodynamic heuristics and pinch theory. Additionally, a comprehensive methodology to determine the COE from a process site has been developed. In this work, we have established thermodynamic and economic comparisons between IGCC sites with and without CCS and a trade-off between the degree of decarbonisation and the COE from the heat integrated IGCC sites. The results show that the COE from the heat integrated decarbonised IGCC sites is significantly lower compared to IGCC sites without heat integration making application of CCS in IGCC sites economically competitive.

  2. Effects of combined heat and x-rays on tumours in mice

    International Nuclear Information System (INIS)

    Hill, S.A.

    1980-08-01

    The therapeutic potential of combined hyperthermia and radiation was investigated in six different types of experimental mouse tumour. Their response to hyperthermia alone and combined heat and X-ray treatments was assessed by delay in tumour regrowth. Thermal sensitivity was found to vary from tumour to tumour. The importance of the order of application and the time interval between treatments was investigated, and the tumour response compared with that of mouse skin as an example of a normal tissue. A therapeutic gain was not seen for X-rays and heat in close sequence. It was however seen when heat was applied several hours after irradiation. Constriction of the tumour blood supply, either artificially, or naturally by implantation into a constricted site, was found to increase thermal sensitivity dramatically. Possible reasons for this are discussed. Heat applied immediately before irradiation may result in a small increase in metastatic spread. Heat applied at other times did not influence the metastatic incidence. Immersion in hot water was examined as a method of heating experimental mouse tumours, and was found to be inadequate in terms of the temperature uniformity achieved. The influence of this factor on results using water bath heating are discussed. (author)

  3. Combined heat and power in the City

    Energy Technology Data Exchange (ETDEWEB)

    Crafter, A. [Corporation of London (United Kingdom). Dept. of Technical Services

    2002-03-01

    This article reports on the development of a large-scale combined heat and power community energy scheme within the City of London. Supported by the Corporation of London and using its own buildings to provide the heating and cooling loads, the scheme has established a power plant close to Smithfield Meat Market and supplies district heating and chilled water for air conditioning to its own properties and some private customers in the nearby districts. Details are given of the power plant which is sited in a conservation area with limited access, the use of absorption chillers to produce the chilled water, the estimated amount of carbon dioxide emissions saved, and the financial benefits of the scheme.

  4. New waste heat district heating system with combined heat and power based on absorption heat exchange cycle in China

    International Nuclear Information System (INIS)

    Sun Fangtian; Fu Lin; Zhang Shigang; Sun Jian

    2012-01-01

    A new waste heat district heating system with combined heat and power based on absorption heat exchange cycle (DHAC) was developed to increase the heating capacity of combined heat and power (CHP) through waste heat recovery, and enhance heat transmission capacity of the existing primary side district heating network through decreasing return water temperature by new type absorption heat exchanger (AHE). The DHAC system and a conventional district heating system based on CHP (CDH) were analyzed in terms of both thermodynamics and economics. Compared to CDH, the DHAC increased heating capacity by 31% and increased heat transmission capacity of the existing primary side district heating network by 75%. The results showed that the exergetic efficiency of DHAC was 10.41% higher and the product exergy monetary cost was 36.6¥/GJ less than a CHD. DHAC is an effective way to increase thermal utilization factor of CHP, and to reduce district heating cost. - Highlights: ► Absorption heat pumps are used to recover waste heat in CHP. ► Absorption heat exchanger can reduce exergy loss in the heat transfer process. ► New waste heat heating system (DHAC) can increase heating capacity of CHP by 31%. ► DHAC can enhance heat transmission capacity of the primary pipe network by 75%. ► DHAC system has the higher exergetic efficiency and the better economic benefit.

  5. Evaluating the potential of process sites for waste heat recovery

    International Nuclear Information System (INIS)

    Oluleye, Gbemi; Jobson, Megan; Smith, Robin; Perry, Simon J.

    2016-01-01

    energy efficiency could increase by 33%. The methodology also shows that combining technologies into a system creates greater potential to exploit the available waste heat in process sites.

  6. Thermodynamic analysis on theoretical models of cycle combined heat exchange process: The reversible heat exchange process

    International Nuclear Information System (INIS)

    Zhang, Chenghu; Li, Yaping

    2017-01-01

    Concept of reversible heat exchange process as the theoretical model of the cycle combined heat exchanger could be useful to determine thermodynamics characteristics and the limitation values in the isolated heat exchange system. In this study, the classification of the reversible heat exchange processes is presented, and with the numerical method, medium temperature variation tendency and the useful work production and usage in the whole process are investigated by the construction and solution of the mathematical descriptions. Various values of medium inlet temperatures and heat capacity ratio are considered to analyze the effects of process parameters on the outlet temperature lift/drop. The maximum process work transferred from the Carnot cycle region to the reverse cycle region is also researched. Moreover, influence of the separating point between different sub-processes on temperature variation profile and the process work production are analyzed. In addition, the heat-exchange-enhancement-factor is defined to study the enhancement effect of the application of the idealized process in the isolated heat exchange system, and the variation degree of this factor with process parameters change is obtained. The research results of this paper can be a theoretical guidance to construct the cycle combined heat exchange process in the practical system. - Highlights: • A theoretical model of Cycle combined heat exchange process is proposed. • The classification of reversible heat exchange process are presented. • Effects of Inlet temperatures and heat capacity ratio on process are analyzed. • Process work transmission through the whole process is studied. • Heat-exchange-enhancement-factor can be a criteria to express the application effect of the idealized process.

  7. Combined Influence of Strain and Heat Loss on Turbulent Premixed Flame Stabilization

    KAUST Repository

    Tay-Wo-Chong, Luis; Zellhuber, Mathieu; Komarek, Thomas; Im, Hong G.; Polifke, Wolfgang

    2015-01-01

    relation in terms of Markstein number, Karlovitz Number and a non-dimensional heat loss parameter was proposed for the combined influence of strain and heat losses on the consumption speed. Combining this empirical relation with a presumed probability

  8. Integrated multiscale simulation of combined heat and power based district heating system

    International Nuclear Information System (INIS)

    Li, Peifeng; Nord, Natasa; Ertesvåg, Ivar Ståle; Ge, Zhihua; Yang, Zhiping; Yang, Yongping

    2015-01-01

    Highlights: • Simulation of power plant, district heating network and heat users in detail and integrated. • Coupled calculation and analysis of the heat and pressure losses of the district heating network. • District heating is not preferable for very low heat load due to relatively high heat loss. • Lower design supply temperatures of the district heating network give higher system efficiency. - Abstract: Many studies have been carried out separately on combined heat and power and district heating. However, little work has been done considering the heat source, the district heating network and the heat users simultaneously, especially when it comes to the heating system with large-scale combined heat and power plant. For the purpose of energy conservation, it is very important to know well the system performance of the integrated heating system from the very primary fuel input to the terminal heat users. This paper set up a model of 300 MW electric power rated air-cooled combined heat and power plant using Ebsilon software, which was validated according to the design data from the turbine manufacturer. Then, the model of heating network and heat users were developed based on the fundamental theories of fluid mechanics and heat transfer. Finally the combined heat and power based district heating system was obtained and the system performances within multiscale scope of the system were analyzed using the developed Ebsilon model. Topics with regard to the heat loss, the pressure drop, the pump power consumption and the supply temperatures of the district heating network were discussed. Besides, the operational issues of the integrated system were also researched. Several useful conclusions were drawn. It was found that a lower design primary supply temperature of the district heating network would give a higher seasonal energy efficiency of the integrated system throughout the whole heating season. Moreover, it was not always right to relate low design

  9. Simulation of a combined heating, cooling and domestic hot water system based on ground source absorption heat pump

    International Nuclear Information System (INIS)

    Wu, Wei; You, Tian; Wang, Baolong; Shi, Wenxing; Li, Xianting

    2014-01-01

    Highlights: • A combined heating/cooling/DHW system based on GSAHP is proposed in cold regions. • The soil imbalance is effectively reduced and soil temperature can be kept stable. • 20% and 15% of condensation/absorption heat is recovered by GSAHP to produce DHW. • The combined system can improve the primary energy efficiency by 23.6% and 44.4%. - Abstract: The amount of energy used for heating and domestic hot water (DHW) is very high and will keep increasing. The conventional ground source electrical heat pump used in heating-dominated buildings has the problems of thermal imbalance, decrease of soil temperature, and deterioration of heating performance. Ground source absorption heat pump (GSAHP) is advantageous in both imbalance reduction and primary energy efficiency (PEE) improvement; however, the imbalance is still unacceptable in the warmer parts of cold regions. A combined heating/cooling/DHW (HCD) system based on GSAHP is proposed to overcome this problem. The GSAHPs using generator absorber heat exchange (GAX) and single-effect (SE) cycles are simulated to obtain the performance under various working conditions. Different HCD systems in Beijing and Shenyang are simulated comparatively in TRNSYS, based on which the thermal imbalance, soil temperature, heat recovery, and energy efficiency are analyzed. Results show that GSAHP–GAX–HCD is suitable for Beijing and GSAHP–SE–HCD is suitable for Shenyang. The imbalance ratio can be reduced to −14.8% in Beijing and to 6.0% in Shenyang with an annual soil temperature variation of only 0.5 °C and 0.1 °C. Furthermore, about 20% and 15% of the total condensation/absorption heat is recovered to produce DHW, and the PEE can reach 1.516 in Beijing and 1.163 in Shenyang. The combined HCD systems can achieve a PEE improvement of 23.6% and 44.4% compared with the normal heating/cooling systems

  10. CHP in Switzerland from 1990 to 1998. Thermal power generation including combined heat and power

    International Nuclear Information System (INIS)

    Kaufmann, U.

    1999-01-01

    The results of a study on thermal power generation in Switzerland show that combined heat and power (CHP) systems have grown rapidly. Statistics are presented on the development of CHP-based power and also on thermal power stations without waste heat usage. Figures are given for gas and steam turbine installations, combined gas and steam turbine stations and motor-driven CHP units. Power production is categorised, separating small and large (over 1 Megawatt electrical) power generation facilities. On-site, distributed power generation at consumers' premises and the geographical distribution of plant is described

  11. Solitary heat waves in nonlinear lattices with squared on-site potential

    Indian Academy of Sciences (India)

    A model Hamiltonian is proposed for heat conduction in a nonlinear lattice with squared on-site potential using the second quantized operators and averaging the same using a suitable wave function, equations are derived in discrete form for the field amplitude and the properties of heat transfer are examined theoretically.

  12. Combined Influence of Strain and Heat Loss on Turbulent Premixed Flame Stabilization

    KAUST Repository

    Tay-Wo-Chong, Luis

    2015-11-16

    The present paper argues that the prediction of turbulent premixed flames under non-adiabatic conditions can be improved by considering the combined effects of strain and heat loss on reaction rates. The effect of strain in the presence of heat loss on the consumption speed of laminar premixed flames was quantified by calculations of asymmetric counterflow configurations (“fresh-to-burnt”) with detailed chemistry. Heat losses were introduced by setting the temperature of the incoming stream of products on the “burnt” side to values below those corresponding to adiabatic conditions. The consumption speed decreased in a roughly exponential manner with increasing strain rate, and this tendency became more pronounced in the presence of heat losses. An empirical relation in terms of Markstein number, Karlovitz Number and a non-dimensional heat loss parameter was proposed for the combined influence of strain and heat losses on the consumption speed. Combining this empirical relation with a presumed probability density function for strain in turbulent flows, an attenuation factor that accounts for the effect of strain and heat loss on the reaction rate in turbulent flows was deduced and implemented into a turbulent combustion model. URANS simulations of a premixed swirl burner were carried out and validated against flow field and OH chemiluminescence measurements. Introducing the effects of strain and heat loss into the combustion model, the flame topology observed experimentally was correctly reproduced, with good agreement between experiment and simulation for flow field and flame length.

  13. Solitary heat waves in nonlinear lattices with squared on-site potential

    Indian Academy of Sciences (India)

    Abstract. A model Hamiltonian is proposed for heat conduction in a nonlinear lattice with squared on-site potential using the second quantized operators and averaging the same using a suitable wave function, equations are derived in discrete form for the field amplitude and the prop- erties of heat transfer are examined ...

  14. Radiation and combined heat transfer in channels

    International Nuclear Information System (INIS)

    Tamonis, M.

    1986-01-01

    This book presents numerical methods of calculation of radiative and combined heat transfer in channel flows of radiating as well as nonradiating media. Results obtained in calculations for flow conditions of combustion products from organic fuel products are given and methods used in determining the spectral optical properties of molecular gases are analyzed. The book presents applications of heat transfer in solving problems. Topic covered are as follows: optical properties of molecular gases; transfer equations for combined heat transfer; experimental technique; convective heat transfer in heated gas flows; radiative heat transfer in gaseous media; combined heat transfer; and radiative and combined heat transfer in applied problems

  15. Dry heat and radiation combination effects on Aspergillus flavus Link. infecting cocoa beans

    International Nuclear Information System (INIS)

    Amoako-Atta, B.; Meier, H.; Odamtten, G.T.

    1981-01-01

    The paper deals with the effect of heat and radiation combination treatments on the control of microbial spoilage of cocoa beans caused by toxigenic Aspergillus flavus Link. The heat and radiation sources were from dry air oven heat and 60 Co gammacell 220 irradiator, respectively. The radiation doses used were either 0, 50, 100, 150 or 200 krad, with combined heat temperatures of 30, 60 or 90 0 C. At each temperature level three different exposure time intervals of either 15 min, 30 min or 60 min respectively, were used. Two reversible sequential heat/radiation combination effects were evaluated. The first sequence involved cocoa beans inoculated with A. flavus spores exposed first to dry heat at pre-determined temperature heat exposure time, followed by radiation treatment, then retention of samples in a constant humidity environmental chamber set at 80% for daily observation up to forty days post-treatment. The second sequence involved exposure of the inoculated beans first to radiation, then to heat before retention under fixed RH for observation. From their results, the authors arrive at four conclusions: first, that there is a critical radiation/heat combination range (200, 150 and 100 krad/90 0 C for 15 min) that significantly decontaminates (less than 5% mouldiness) A. flavus infected cocoa beans even under high relative humidity (80% RH) environment; second, that a temperature level of 90 0 C combined with 200, 150 or 100 krad maximizes such effect but the heat exposure time is a major factor; third, that low heat temperature ranges of 30 or 60 0 C, combined with low radiation dosages of 150 krad or below, enhance the rate of A. flavus spoilage effects of cocoa beans; and, lastly, that the sequence of exposure of the inoculated cocoa beans to heat/radiation combination influenced the spore germination; exposure to heat before radiation would sensitize the spores (200 krad/90 0 C) but results in an increased radioresistance. (author)

  16. Combined heat and power considered as a virtual steam cycle heat pump

    International Nuclear Information System (INIS)

    Lowe, Robert

    2011-01-01

    The first aim of this paper is to shed light on the thermodynamic reasons for the practical pursuit of low temperature operation by engineers involved in the design and the operation of combined heat and power (CHP) and district heating (DH) systems. The paper shows that the steam cycle of a combined heat and power generator is thermodynamically equivalent to a conventional steam cycle generator plus an additional virtual steam cycle heat pump. This apparently novel conceptualisation leads directly to (i) the observed sensitivity of coefficient of performance of CHP to supply and return temperatures in associated DH systems, and (ii) the conclusion that the performance of CHP will tend to be significantly higher than real heat pumps operating at similar temperatures. The second aim, which is pursued more qualitatively, is to show that the thermodynamic performance advantages of CHP are consistent with the goal of deep, long-term decarbonisation of industrialised economies. As an example, estimates are presented, which suggest that CHP based on combined-cycle gas turbines with carbon capture and storage has the potential to reduce the carbon intensity of delivered heat by a factor of ∼30, compared with a base case of natural gas-fired condensing boilers. - Highlights: → Large-scale CHP systems are thermodynamically equivalent to virtual steam cycle heat pumps. → COPs of such virtual heat pumps are necessarily better than the Carnot limit for real heat pumps. → COPs can approach 9 for plant matched to district heating systems with flow temperatures of 90 deg. C. → CHP combined with CCGT and CCS can reduce the carbon intensity of delivered heat ∼30-fold.

  17. Performances of nuclear power plants for combined production of electricity and hot water for district heating

    International Nuclear Information System (INIS)

    Bronzen, S.

    The possibilities for using nuclear power plants for combined production of heat and power seem to be very good in the future. With the chosen 600 MWsub (e) BWR plant a heat output up to 1200 MW can be arranged. An alternative, consisting of steam extractions from the low-pressure turbine, offers a flexible solution for heat and power generation. With this alternative the combined plant can use components from normal condensing nuclear power plants. The flexible extraction design also offers a real possibility for using the combined plant in electric peak generation. However, urban siting requires long distance heat transmission and the pipe design for this transmission is a major problem when planning and optimizing the whole nuclear combined heat and power plant. (author)

  18. Large heat storage tank for load management nd implementation of ambient heat. District heating networks based on combined heat and power; Grosswaermespeicher zum Lastmanagement und zur Einbindung von Umweltenergie. Auf KWK basierende Fernwaermenetze

    Energy Technology Data Exchange (ETDEWEB)

    Gross, Sebastian; Rhein, Martin; Ruehling, Karin [Technische Universitaet Dresden (Germany). Inst. fuer Energietechnik

    2013-06-15

    The district heating based on combined heat and power is a transitional technology on the way to the supply of Germany with renewable energy. In the next years, this transitional technology can only be maintained and expanded when marketability is given. Therefore an appropriate combination has to be found from investment measures. Together with new aspects in the management strategy, these investment measures should significantly improve the marketability. The investment measures also aims to enable a primary energetic, appropriate combination of natural gas-based combined heat and power, renewable energy sources (solar thermal energy, ambient heat) and heat pump technology.

  19. Combined system of solar heating and cooling using heat pump

    International Nuclear Information System (INIS)

    Zakhidov, R.A.; Anarbaev, A.I.

    2014-01-01

    The heating and cooling systems of apartment buildings based on combined solar heat-pump equipment has been considered and the procedure of calculating its parameters has been worked out. A technical-economic analysis has been performed and compared with the boiler-setting version. (author)

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

    Directory of Open Access Journals (Sweden)

    Yan Xu

    2017-11-01

    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

  1. Demonstration of an on-site PAFC cogeneration system with waste heat utilization by a new gas absorption chiller

    Energy Technology Data Exchange (ETDEWEB)

    Urata, Tatsuo [Tokyo Gas Company, LTD, Tokyo (Japan)

    1996-12-31

    Analysis and cost reduction of fuel cells is being promoted to achieve commercial on-site phosphoric acid fuel cells (on-site FC). However, for such cells to be effectively utilized, a cogeneration system designed to use the heat generated must be developed at low cost. Room heating and hot-water supply are the most simple and efficient uses of the waste heat of fuel cells. However, due to the short room-heating period of about 4 months in most areas in Japan, the sites having demand for waste heat of fuel cells throughout the year will be limited to hotels and hospitals Tokyo Gas has therefore been developing an on-site FC and the technology to utilize tile waste heat of fuel cells for room cooling by means of an absorption refrigerator. The paper describes the results of fuel cell cogeneration tests conducted on a double effect gas absorption chiller heater with auxiliary waste heat recovery (WGAR) that Tokyo Gas developed in its Energy Technology Research Laboratory.

  2. Exertional heat illness incidence and on-site medical team preparedness in warm weather

    Science.gov (United States)

    Hosokawa, Yuri; Adams, William M.; Belval, Luke N.; Davis, Robert J.; Huggins, Robert A.; Jardine, John F.; Katch, Rachel K.; Stearns, Rebecca L.; Casa, Douglas J.

    2018-03-01

    To investigate the influence of estimated wet bulb globe temperature (WBGT) and the International Institute of Race Medicine (IIRM) activity modification guidelines on the incidence of exertional heat stroke (EHS) and heat exhaustion (HEx) and the ability of an on-site medical team to treat those afflicted. Medical records of EHS and HEx patients over a 17-year period from the New Balance Falmouth Road Race were examined. Climatologic data from nearby weather stations were obtained to calculate WBGT with the Australian Bureau of Meteorology (WBGTA) and Liljegren (WBGTL) models. Incidence rate (IR) of EHS, HEx, and combined total of EHS and HEx (COM) were calculated, and linear regression analyses were performed to assess the relationship between IR and WBGTA or WBGTL. One-way ANOVA was performed to compare differences in EHS, HEx, and COM incidence to four alert levels in the IIRM guidelines. Incidence of EHS, HEx, and COM was 2.12, 0.98, and 3.10 cases per 1000 finishers. WBGTA explained 48, 4, and 46% of the variance in EHS, HEx, and COM IR; WBGTL explained 63, 13, and 69% of the variance in EHS, HEx, and COM IR. Main effect of WBGTA and WBGTL on the alert levels were observed in EHS and COM IR (p < 0.05). The cumulative number of EHS patients treated did not exceed the number of cold water immersion tubs available to treat them. EHS IR increased as WBGT and IIRM alert level increased, indicating the need for appropriate risk mitigation strategies and on-site medical treatment.

  3. Analysis of the location for peak heating in CHP based combined district heating systems

    International Nuclear Information System (INIS)

    Wang, Haichao; Lahdelma, Risto; Wang, Xin; Jiao, Wenling; Zhu, Chuanzhi; Zou, Pinghua

    2015-01-01

    Combined heat and power (CHP) is the main technology for providing the base load of district heating in China. However, CHP is not efficient for providing the peak load; instead, a peak boiler with high efficiency could be used to compensate the peak load. This paper studies how the location of the peak boiler can affect the energy efficiency and economic performance of such CHP based combined district heating system. Firstly, the connection mode and the control strategy for different peak heating locations are analyzed. Then the effect of the peak boiler's location on the initial investment of the network and the cost for distributing heat is studied. The objective is to place the peak boiler in a location where the overall costs are the smallest. Following this rule, the results indicate that the peak boiler should be located at the CHP plant if that allows using cheaper ‘self-use electricity’ in CHP for distributing the heat. However, if the market electricity price is used everywhere, or if energy efficiency is more emphasized, the location of the peak boiler should be closer to the users with dense heat loads. - Highlights: • Location for peak heating in the CHP based combined DH system is studied. • Regulation or control strategies for combined DH are summarized. • The heat load duration curve for combined DH is demonstrated. • Network design for combined DH with peak boiler outside of the CHP is analyzed

  4. Combination solar photovoltaic heat engine energy converter

    Science.gov (United States)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  5. Combined facial heating and inhalation of hot air do not alter thermoeffector responses in humans

    Science.gov (United States)

    Wingo, Jonathan E.; Low, David A.; Keller, David M.; Kimura, Kenichi

    2015-01-01

    The influence of thermoreceptors in human facial skin on thermoeffector responses is equivocal; furthermore, the presence of thermoreceptors in the respiratory tract and their involvement in thermal homeostasis has not been elucidated. This study tested the hypothesis that hot air directed on the face and inhaled during whole body passive heat stress elicits an earlier onset and greater sensitivity of cutaneous vasodilation and sweating than that directed on an equal skin surface area away from the face. Six men and two women completed two trials separated by ∼1 wk. Participants were passively heated (water-perfused suit; core temperature increase ∼0.9°C) while hot air was directed on either the face or on the lower leg (counterbalanced). Skin blood flux (laser-Doppler flowmetry) and local sweat rate (capacitance hygrometry) were measured at the chest and one forearm. During hot-air heating, local temperatures of the cheek and leg were 38.4 ± 0.8°C and 38.8 ± 0.6°C, respectively (P = 0.18). Breathing hot air combined with facial heating did not affect mean body temperature onsets (P = 0.97 and 0.27 for arm and chest sites, respectively) or slopes of cutaneous vasodilation (P = 0.49 and 0.43 for arm and chest sites, respectively), or the onsets (P = 0.89 and 0.94 for arm and chest sites, respectively), or slopes of sweating (P = 0.48 and 0.65 for arm and chest sites, respectively). Based on these findings, respiratory tract thermoreceptors, if present in humans, and selective facial skin heating do not modulate thermoeffector responses during passive heat stress. PMID:26157054

  6. Exertional heat illness incidence and on-site medical team preparedness in warm weather.

    Science.gov (United States)

    Hosokawa, Yuri; Adams, William M; Belval, Luke N; Davis, Robert J; Huggins, Robert A; Jardine, John F; Katch, Rachel K; Stearns, Rebecca L; Casa, Douglas J

    2018-03-29

    To investigate the influence of estimated wet bulb globe temperature (WBGT) and the International Institute of Race Medicine (IIRM) activity modification guidelines on the incidence of exertional heat stroke (EHS) and heat exhaustion (HEx) and the ability of an on-site medical team to treat those afflicted. Medical records of EHS and HEx patients over a 17-year period from the New Balance Falmouth Road Race were examined. Climatologic data from nearby weather stations were obtained to calculate WBGT with the Australian Bureau of Meteorology (WBGT A ) and Liljegren (WBGT L ) models. Incidence rate (IR) of EHS, HEx, and combined total of EHS and HEx (COM) were calculated, and linear regression analyses were performed to assess the relationship between IR and WBGT A or WBGT L . One-way ANOVA was performed to compare differences in EHS, HEx, and COM incidence to four alert levels in the IIRM guidelines. Incidence of EHS, HEx, and COM was 2.12, 0.98, and 3.10 cases per 1000 finishers. WBGT A explained 48, 4, and 46% of the variance in EHS, HEx, and COM IR; WBGT L explained 63, 13, and 69% of the variance in EHS, HEx, and COM IR. Main effect of WBGT A and WBGT L on the alert levels were observed in EHS and COM IR (p < 0.05). The cumulative number of EHS patients treated did not exceed the number of cold water immersion tubs available to treat them. EHS IR increased as WBGT and IIRM alert level increased, indicating the need for appropriate risk mitigation strategies and on-site medical treatment.

  7. Heat pumps in combined heat and power systems

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    2014-01-01

    Heat pumps have previously been proposed as a way to integrate higher amounts of renewable energy in DH (district heating) networks by integrating, e.g., wind power. The paper identifies and compares five generic configurations of heat pumps in DH systems. The operational performance...... of the considered cases. When considering a case where the heat pump is located at a CHP (combined heat and power) plant, a configuration that increases the DH return temperature proposes the lowest operation cost, as low as 12 EUR MWh-1 for a 90 °C e 40 °C DH network. Considering the volumetric heating capacity......, a third configuration is superior in all cases. Finally, the three most promising heat pump configurations are integrated in a modified PQ-diagram of the CHP plant. Each show individual advantages, and for two, also disadvantages in order to achieve flexible operation....

  8. Preliminary Analysis on Heat Removal Capacity of Passive Air-Water Combined Cooling Heat Exchanger Using MARS

    International Nuclear Information System (INIS)

    Kim, Seung-Sin; Jeon, Seong-Su; Hong, Soon-Joon; Bae, Sung-Won; Kwon, Tae-Soon

    2015-01-01

    Current design requirement for working time of PAFS heat exchanger is about 8 hours. Thus, it is not satisfied with the required cooling capability for the long term SBO(Station Black-Out) situation that is required to over 72 hours cooling. Therefore PAFS is needed to change of design for 72 hours cooling. In order to acquirement of long terms cooling using PAFS, heat exchanger tube has to be submerged in water tank for long time. However, water in the tank is evaporated by transferred heat from heat exchanger tubes, so water level is gradually lowered as time goes on. The heat removal capacity of air cooling heat exchanger is core parameter that is used for decision of applicability on passive air-water combined cooling system using PAFS in long term cooling. In this study, the development of MARS input model and plant accident analysis are performed for the prediction of the heat removal capacity of air cooling heat exchanger. From analysis result, it is known that inflow air velocity is the decisive factor of the heat removal capacity and predicted air velocity is lower than required air velocity. But present heat transfer model and predicted air velocity have uncertainty. So, if changed design of PAFS that has over 4.6 kW heat removal capacity in each tube, this type heat exchanger can be applied to long term cooling of the nuclear power plant

  9. Combined impact of transient heat loads and steady-state plasma exposure on tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Alexander, E-mail: A.Huber@fz-juelich.de [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany); Wirtz, Marius; Sergienko, Gennady; Steudel, Isabel [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany); Arakcheev, Aleksey; Burdakov, Aleksander [Budker Institute of Nuclear Physics (BINP), Novosibirsk 630090 (Russian Federation); Esser, Hans Guenter; Freisinger, Michaele; Kreter, Arkadi; Linke, Jochen; Linsmeier, Christian; Mertens, Philippe; Möller, Sören; Philipps, Volker; Pintsuk, Gerald; Reinhart, Michael; Schweer, Bernd [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany); Shoshin, Andrey [Budker Institute of Nuclear Physics (BINP), Novosibirsk 630090 (Russian Federation); Terra, Alexis; Unterberg, Bernhard [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich (Germany)

    2015-10-15

    Highlights: • W-samples under combined loading conditions show a lower damage threshold. • The pre-loaded W-samples show a lower damage threshold due to the D- embrittlement. • Pronounced increase of the D retention has been observed during the combined loads. • Enhanced blister formation has been observed under combined loading conditions. - Abstract: Cracking thresholds and crack patterns in tungsten targets have been studied in recent experiments after repetitive ITER-like ELM heat pulses in combination with plasma exposure in PSI-2 (Γ{sub target} = 2.5–4.0 × 10{sup 21} m{sup −2} s{sup −1}, ion energy on surface E{sub ion} = 60 eV, T{sub e} ≈ 10 eV). The heat pulses were simulated by laser irradiation. A Nd:YAG laser with energy per pulse of up to 32 J and a duration of 1 ms at the fundamental wavelength (λ = 1064 nm, repetition rate 0.5 Hz) was used to irradiate ITER-grade W samples with repetitive heat loads. In contrast to pure thermal exposure with a laser beam where the damage threshold under pure heat loads for ITER-grade W lies between 0.38 and 0.76 GW/m{sup 2}, the experiments with pre-loaded W-samples as well as under combined loading conditions show a lower damage threshold of 0.3 GW/m{sup 2}. This is probably due to deuterium embrittlement and/or a higher defect concentration in a region close to the surface due to supersaturation with deuterium. A pronounced increase in the D retention (more than a factor of five) has been observed during the combined transient heat loads and plasma exposure. Enhanced blister formation has been observed under these combined loading conditions.

  10. Combined impact of transient heat loads and steady-state plasma exposure on tungsten

    International Nuclear Information System (INIS)

    Huber, Alexander; Wirtz, Marius; Sergienko, Gennady; Steudel, Isabel; Arakcheev, Aleksey; Burdakov, Aleksander; Esser, Hans Guenter; Freisinger, Michaele; Kreter, Arkadi; Linke, Jochen; Linsmeier, Christian; Mertens, Philippe; Möller, Sören; Philipps, Volker; Pintsuk, Gerald; Reinhart, Michael; Schweer, Bernd; Shoshin, Andrey; Terra, Alexis; Unterberg, Bernhard

    2015-01-01

    Highlights: • W-samples under combined loading conditions show a lower damage threshold. • The pre-loaded W-samples show a lower damage threshold due to the D- embrittlement. • Pronounced increase of the D retention has been observed during the combined loads. • Enhanced blister formation has been observed under combined loading conditions. - Abstract: Cracking thresholds and crack patterns in tungsten targets have been studied in recent experiments after repetitive ITER-like ELM heat pulses in combination with plasma exposure in PSI-2 (Γ_t_a_r_g_e_t = 2.5–4.0 × 10"2"1 m"−"2 s"−"1, ion energy on surface E_i_o_n = 60 eV, T_e ≈ 10 eV). The heat pulses were simulated by laser irradiation. A Nd:YAG laser with energy per pulse of up to 32 J and a duration of 1 ms at the fundamental wavelength (λ = 1064 nm, repetition rate 0.5 Hz) was used to irradiate ITER-grade W samples with repetitive heat loads. In contrast to pure thermal exposure with a laser beam where the damage threshold under pure heat loads for ITER-grade W lies between 0.38 and 0.76 GW/m"2, the experiments with pre-loaded W-samples as well as under combined loading conditions show a lower damage threshold of 0.3 GW/m"2. This is probably due to deuterium embrittlement and/or a higher defect concentration in a region close to the surface due to supersaturation with deuterium. A pronounced increase in the D retention (more than a factor of five) has been observed during the combined transient heat loads and plasma exposure. Enhanced blister formation has been observed under these combined loading conditions.

  11. On-Site or Off-Site Renewable Energy Supply Options?

    DEFF Research Database (Denmark)

    Marszal, Anna Joanna; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    The concept of a Net Zero Energy Building (Net ZEB) encompasses two options of supplying renewable energy, which can offset energy use of a building, in particular on-site or off-site renewable energy supply. Currently, the on-site options are much more popular than the off-site; however, taking...... into consideration the limited area of roof and/or façade, primarily in the dense city areas, the Danish weather conditions, the growing interest and number of wind turbine co-ops, the off-site renewable energy supply options could become a meaningful solution for reaching ‘zero’ energy goal in the Danish context...... five technologies, i.e., two on-site options: (1) photovoltaic, (2) micro combined heat and power, and three off-site options: (1) off-site windmill, (2) share of a windmill farm and (3) purchase of green energy from the 100% renewable utility grid. The results indicate that in case of the on...

  12. Residential CO{sub 2} heat pump system for combined space heating and hot water heating

    Energy Technology Data Exchange (ETDEWEB)

    Stene, Joern

    2004-02-01

    Carbon dioxide (CO{sub 2}, R-744) has been identified as a promising alternative to conventional working fluids in a number of applications due to its favourable environmental and thermophysical properties. Previous work on residential CO{sub 2} heat pumps has been dealing with systems for either space heating or hot water heating, and it was therefore considered interesting to carry out a theoretical and experimental study of residential CO{sub 2} heat pump systems for combined space heating and hot water heating - o-called integrated CO{sub 2} heat pump systems. The scope of this thesis is limited to brine-to-water and water-to-water heat pumps connected to low-temperature hydronic space heating systems. The main conclusions are: (1) Under certain conditions residential CO{sub 2} heat pump systems for combined space heating and hot water heating may achieve the same or higher seasonal performance factor (SPF) than the most energy efficient state-of-the-art brine-to-water heat pumps. (2) In contrary to conventional heat pump systems for combined space heating and DHW heating, the integrated CO{sub 2} heat pump system achieves the highest COP in the combined heating mode and the DHW heating mode, and the lowest COP in the space heating mode. Hence, the larger the annual DHW heating demand, the higher the SPF of the integrated CO{sub 2} heat pump system. (3) The lower the return temperature in the space heating system and the lower the DHW storage temperature, the higher the COP of the integrated CO{sub 2} heat pump. A low return temperature in the space heating system also results in a moderate DHW heating capacity ratio, which means that a relatively large part of the annual space heating demand can be covered by operation in the combined heating mode, where the COP is considerably higher than in the space heating mode. (4) During operation in the combined heating mode and the DHW heating mode, the COP of the integrated CO{sub 2} heat pump is heavily influenced by

  13. Heat losses and thermal performance of commercial combined solar and pellet heating systems

    OpenAIRE

    Fiedler, Frank; Persson, Tomas; Bales, Chris; Nordlander, Svante

    2004-01-01

    Various pellet heating systems are marketed in Sweden, some of them in combination with a solar heating system. Several types of pellet heating units are available and can be used for a combined system. This article compares four typical combined solar and pellet heating systems: System 1 and 2 two with a pellet stove, system 3 with a store integrated pellet burner and system 4 with a pellet boiler. The lower efficiency of pellet heaters compared to oil or gas heaters increases the primary en...

  14. Experimental Investigation of the Combined Effects of Heat Exchanger Geometries on Nucleate Pool Boiling Heat Transfer in a Scaled IRWST

    International Nuclear Information System (INIS)

    Kang, Myeong Gie; Chun, Moon Hyun

    1996-01-01

    In an effort to determine the combined effects of major parameters of heat exchanger tubes on the nucleate pool boiling heat transfer in the scaled in-containment refueling water storage tank (IRWST), a total of 1,966 data for q v ersus ΔT has been obtained using various combinations of tube diameters, surface roughness, and tube orientations. The experimental results show that (1) increased surface roughness enhances heat transfer for both horizontal and vertical tubes, (2) the two heat transfer mechanisms, i.e.,enhanced heat transfer for both horizontal and vertical tubes, (2) the two heat transfer mechanisms, i.e., enhanced heat transfer due to liquid agitation by bubbles generated and reduced heat transfer by the formation of large vapor slugs and bubble coalescence are different in two regions of low heat fluxes (q ≤ 50kW/m 2 ) and high heat fluxes (q > 50kW/m 2 ) depending on the orientation of tubes and the degree of surface roughness, and (3) the heat transfer rate decreases as the tube diameter is increased for both horizontal and vertical tubes, but the effect of tube diameter on the nucleate pool boiling heat transfer for vertical tubes is greater than that for horizontal tubes. Two empirical heat transfer correlations for q , one for horizontal tubes and the other for vertical tubes, are obtained in terms of surface roughness (ε) and tube diameter (D). In addition, a simple empirical correlation for nucleate pool boiling heat transfer coefficient (h b ) is obtained as a function of heat flux (q ) only. 9 figs., 4 tabs., 15 refs. (Author)

  15. Potentialities and type of integrating nuclear heating stations into district heating systems

    International Nuclear Information System (INIS)

    Munser, H.; Reetz, B.; Schmidt, G.

    1978-01-01

    Technical and economical potentialities of applying nuclear heating stations in district heating systems are discussed considering the conditions of the GDR. Special attention is paid to an optimum combination of nuclear heating stations with heat sources based on organic fuels. Optimum values of the contribution of nuclear heating stations to such combined systems and the economic power range of nuclear heating stations are estimated. Final considerations are concerned with the effect of siting and safety concepts of nuclear heating stations on the structure of the district heating system. (author)

  16. Experiments on FW-IBW mode conversion heating combined with LHCD on Tore Supra

    International Nuclear Information System (INIS)

    Basiuk, V.; Becoulet, A.; Imbeaux, F.; Nguyen, F.; Peysson, Y.; Monakhov, I.; Petrov, Y.; Petrov, Y.

    1999-01-01

    Recent RF heating and current drive investigations revealed a growing interest in a scheme based on mode conversion (MC) of externally excited fast waves (FW) to ion Bernstein waves (IBW). Suitability of MC scheme for on/off axis electron heating has already been reported on Tore Supra. New results, which were obtained during MC experiments combined with Low Hybrid Current Drive (LHCD) are presented in this paper. Application of new experimental tools and numerical techniques provided better insight into the problem of MC power deposition. an outcome of active search for synergistic LHCD-IBW current drive effects is also reported

  17. Control of food-borne molds by combination of heat and radiation

    International Nuclear Information System (INIS)

    Padwal-Desai, S.R.; Bongirwar, D.R.

    1979-01-01

    After enumerating the fungi responsible for food spoilage, work done on the factors influencing growth of fungi in stored foods is reviewed and the methods using heat, radiation or chemicals for control of food-borne molds are briefly surveyed. Work on combination process employing heat treatment and radiation treatment is reviewed in detail. The review covers the following aspects: (1) theory and engineering aspects of combination process of heat and radiation including modes of heat transfer, radiation physics, radiation sources, heat radiation effect and calculation of energy balance of the process, (2) biological effects of heat, radiation and heat-radiation combination treatments on mold growth with special reference to DNA and (3) application of the process for mold control in cereal products, nuts and raisins and fruits. Heat treatment and radiation treatment have been found to complement each other and when given in proper sequence show synergism. Design requirements of radiation sources and heat transfer equipment are also surveyed. (M.G.B.)

  18. Climatic and psychosocial risks of heat illness incidents on construction site.

    Science.gov (United States)

    Jia, Yunyan Andrea; Rowlinson, Steve; Ciccarelli, Marina

    2016-03-01

    The study presented in this paper aims to identify prominent risks leading to heat illness in summer among construction workers that can be prioritised for developing effective interventions. Samples are 216 construction workers' cases at the individual level and 26 construction projects cases at the organisation level. A grounded theory is generated to define the climatic heat and psychosocial risks and the relationships between risks, timing and effectiveness of interventions. The theoretical framework is then used to guide content analysis of 36 individual onsite heat illness cases to identify prominent risks. The results suggest that heat stress risks on construction site are socially constructed and can be effectively managed through elimination at supply chain level, effective engineering control, proactive control of the risks through individual interventions and reactive control through mindful recognition and response to early symptoms. The role of management infrastructure as a base for effective interventions is discussed. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  19. A study of the rates of heat transfer and bubble site density for nucleate boiling on an inclined heating surface

    International Nuclear Information System (INIS)

    Bonamy, S.E.; Symons, J.G.

    1974-08-01

    Nucleate pool boiling of distilled water from an electrically heated surface at atmospheric pressure is studied for varying heating surface inclinations. The constants of the accepted boiling equation phi = K Tsup(B) and the Rohsenow Correlation Coefficient are found to be dependent on surface orientation. Convection cooling is observed to play a major role in pool boiling phenomena and causes large changes in the heat transfer rates for a given excess of temperature of the heated surface. Active nucleation site density is studied and found to be independent of surface inclination. Empirical relations are presented to provide an understanding of the effects of inclination on other boiling parameters. (author)

  20. Social anthropological and interdisciplinary research on the conversion of electrically heated single family houses to heating by combined pellet-solar systems

    International Nuclear Information System (INIS)

    Henning, Annette

    2004-01-01

    The social anthropological research presented here is part of the interdisciplinary research project PESTO, which focuses on the (partial or complete) conversion of single family houses from electric heating to heating by combined pellet-solar heating systems. Basic to this research is the assumption that it is more likely that energy conversions are carried through, and that they are successful on a long-term basis, if the new products are designed to fit as well as possible into the everyday lives of people. The anthropological interest in the project can be divided into two parts; motives for or against a conversion among men and women in Swedish households, and product design and placement in (previously) electrically heated single-family houses. Literature studies and semi-structured qualitative interviews are the main methods used in the anthropological part of the project. During the next 3-year project period, these investigations will be used to support information and marketing, and to formulate recommendations for conversion practice of electrically heated single-family houses to combined pellet-solar heating. (Author)

  1. Instant, Visual, and Instrument-Free Method for On-Site Screening of GTS 40-3-2 Soybean Based on Body-Heat Triggered Recombinase Polymerase Amplification.

    Science.gov (United States)

    Wang, Rui; Zhang, Fang; Wang, Liu; Qian, Wenjuan; Qian, Cheng; Wu, Jian; Ying, Yibin

    2017-04-18

    On-site monitoring the plantation of genetically modified (GM) crops is of critical importance in agriculture industry throughout the world. In this paper, a simple, visual and instrument-free method for instant on-site detection of GTS 40-3-2 soybean has been developed. It is based on body-heat recombinase polymerase amplification (RPA) and followed with naked-eye detection via fluorescent DNA dye. Combining with extremely simplified sample preparation, the whole detection process can be accomplished within 10 min and the fluorescent results can be photographed by an accompanied smart phone. Results demonstrated a 100% detection rate for screening of practical GTS 40-3-2 soybean samples by 20 volunteers under different ambient temperatures. This method is not only suitable for on-site detection of GM crops but also demonstrates great potential to be applied in other fields.

  2. Temporary heat storage by using combined heat and power in supplementary lighted greenhouses Proceedings of the Third International Symposium on Artificial Lighting in Horticulture

    NARCIS (Netherlands)

    Huijs, J.P.G.

    1997-01-01

    Because of better utilization possibilities of the produced heat, decentrally located combined heat and power installations achieve a higher energetic efficiency than producing heat and power separately. However, efficiency depends considerably on synchronism of heat and electricity demand. Using a

  3. The effects of combined treatment of irradiation and heat on bacteria escherichia coli and sarcina lutea in dry condition

    International Nuclear Information System (INIS)

    Nikham; Hilmy, Nazly

    1987-01-01

    The effects of combination treatment of irradiation and heat on bacteria escherichia coli and sarcina lutea in dry condition. Investigation on the effects of combined irradiation + heat and heat + irradiation treatments have been carried out i.e. at the doses of 0; 1.0; 1.5; and 2.0 kGy with heating at 50 0 C for 10; 20; and 30 minutes on escherichia coli B/r, escherichia coli from sludge and sarcine lutea. Samples of bacteria were prepared in dry condition by using sterile fine sand as carrier. Irradiation was done in aerobic condition with RH 90% and the time range between irradiation and heating was not more than 2 hours. The results showed that the D 10 value did not give significant difference between the combined irradiation + heat, and heat + irradiation treatments for the 3 species of bacteria, compared to irradiation only (p 0.05). Doses of 1.0 and 1.5 kGy combined with heating at 50 0 C for 10 and 20 minutes gave better results compared to irradiation only. 17 refs

  4. Mitigation of Short-Lived Climate Pollutants from Residential Coal Heating and Combined Heating/Cooking Stoves: Impacts on the Cryosphere, Policy Options, and Co-benefits

    Science.gov (United States)

    Chafe, Z.; Anenberg, S.; Klimont, Z.; Kupiainen, K.; Lewis, J.; Metcalfe, J.; Pearson, P.

    2017-12-01

    Residential solid fuel combustion for cooking, heating, and other energy services contributes to indoor and outdoor air pollution, and creates impacts on the cryosphere. Solid fuel use often occurs in colder climates and at higher elevations, where a wide range of combustion emissions can reduce reflectivity of the snow- and ice-covered surfaces, causing climatic warming. Reducing short-lived climate pollutants (SLCPs), such as black carbon (BC), could have substantial climate and health co-benefits, especially in areas where emissions influence the cryosphere. A review of existing literature and emissions estimates, conducted as part of the Warsaw Summit on BC and Other Emissions from Residential Coal Heating Stoves and Combined Cooking/Heating Stoves, found little nationally-representative data on the fuels and technologies used for heating and combined cooking/heating. The GAINS model estimates that 24 million tonnes of coal equivalent were combusted by households for space heating globally in 2010, releasing 190 kilotons (kt) BC. Emissions from combined cooking/heating are virtually unknown. Policy instruments could mitigate cryosphere-relevant emissions of SLCPs from residential heating or cooking. These include indoor air quality guidelines, stove emission limits, bans on the use of specific fuels, regulatory codes that stipulate when burning can occur, stove changeout programs, and voluntary public education campaigns. These measures are being implemented in countries such as Chile (fuelwood moisture reduction campaign, energy efficiency, heating system improvements), Mongolia (stove renovation, fuel switching), Peru (improved stove programs), Poland (district heating, local fuel bans), United States (stove emission regulation) and throughout the European Community (Ecodesign Directive). Few, if any, of these regulations are likely to reduce emissions from combined cooking/heating. This research team found no global platform to create and share model

  5. Thermodynamic analysis of heat recovery steam generator in combined cycle power plant

    Directory of Open Access Journals (Sweden)

    Ravi Kumar Naradasu

    2007-01-01

    Full Text Available Combined cycle power plants play an important role in the present energy sector. The main challenge in designing a combined cycle power plant is proper utilization of gas turbine exhaust heat in the steam cycle in order to achieve optimum steam turbine output. Most of the combined cycle developers focused on the gas turbine output and neglected the role of the heat recovery steam generator which strongly affects the overall performance of the combined cycle power plant. The present paper is aimed at optimal utilization of the flue gas recovery heat with different heat recovery steam generator configurations of single pressure and dual pressure. The combined cycle efficiency with different heat recovery steam generator configurations have been analyzed parametrically by using first law and second law of thermodynamics. It is observed that in the dual cycle high pressure steam turbine pressure must be high and low pressure steam turbine pressure must be low for better heat recovery from heat recovery steam generator.

  6. The combined effects of wall longitudinal heat conduction and inlet fluid flow maldistribution in crossflow plate-fin heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Ranganayakulu, C. [Aeronautical Development Agency, Bangalore (India); Seetharamu, K.N. [School of Mechanical Engineering, Univ. of Southern Malaysia (KCP), Tronoh (Malaysia)

    2000-05-01

    An analysis of a crossflow plate-fin compact heat exchanger, accounting for the combined effect of two-dimensional longitudinal heat conduction through the exchanger wall and nonuniform inlet fluid flow distribution on both hot and cold fluid sides is carried out using a finite element method. Using the fluid flow maldistribution models, the exchanger effectiveness and its deterioration due to the combined effects of longitudinal heat conduction and flow nonuniformity are calculated for various design and operating conditions of the exchanger. It was found that the performance deteriorations are quite significant in some typical applications due to the combined effects of wall longitudinal heat conduction and inlet fluid flow nonuniformity on crossflow plate-fin heat exchanger. (orig.)

  7. Optimal placement of combined heat and power scheme (cogeneration): application to an ethylbenzene plant

    International Nuclear Information System (INIS)

    Zainuddin Abd Manan; Lim Fang Yee

    2001-01-01

    Combined heat and power (CHP) scheme, also known as cogeneration is widely accepted as a highly efficient energy saving measure, particularly in medium to large scale chemical process plants. To date, CHP application is well established in the developed countries. The advantage of a CHP scheme for a chemical plant is two-fold: (i) drastically cut down on the electricity bill from on-site power generation (ii) to save the fuel bills through recovery of the quality waste heat from power generation for process heating. In order to be effective, a CHP scheme must be placed at the right temperature level in the context of the overall process. Failure to do so might render a CHP venture worthless. This paper discusses the procedure for an effective implementation of a CHP scheme. An ethylbenzene process is used as a case study. A key visualization tool known as the grand composite curves is used to provide an overall picture of the process heat source and heat sink profiles. The grand composite curve, which is generated based on the first principles of Pinch Analysis enables the CHP scheme to be optimally placed within the overall process scenario. (Author)

  8. Drought stress had a predominant effect over heat stress on three tomato cultivars subjected to combined

    DEFF Research Database (Denmark)

    Zhou, Rong; Yu, Xiaqing; Ottosen, Carl-Otto

    2017-01-01

    and relative water content of all cultivars significantly decreased under drought and combined stress as compared to control. The net photosynthesis and starch content were significantly lower under drought and combined stress than control in the three cultivars. Stomata and pore length of the three cultivars......BACKGROUND: Abiotic stresses due to environmental factors could adversely affect the growth and development of crops. Among the abiotic stresses, drought and heat stress are two critical threats to crop growth and sustainable agriculture worldwide. Considering global climate change, incidence...... of combined drought and heat stress is likely to increase. The aim of this study was to shed light on plant growth performance and leaf physiology of three tomatoes cultivars ('Arvento', 'LA1994' and 'LA2093') under control, drought, heat and combined stress. RESULTS: Shoot fresh and dry weight, leaf area...

  9. Life cycle analysis of distributed concentrating solar combined heat and power: economics, global warming potential and water

    Science.gov (United States)

    Norwood, Zack; Kammen, Daniel

    2012-12-01

    We report on life cycle assessment (LCA) of the economics, global warming potential and water (both for desalination and water use in operation) for a distributed concentrating solar combined heat and power (DCS-CHP) system. Detailed simulation of system performance across 1020 sites in the US combined with a sensible cost allocation scheme informs this LCA. We forecast a levelized cost of 0.25 kWh-1 electricity and 0.03 kWh-1 thermal, for a system with a life cycle global warming potential of ˜80 gCO2eq kWh-1 of electricity and ˜10 gCO2eq kWh-1 thermal, sited in Oakland, California. On the basis of the economics shown for air cooling, and the fact that any combined heat and power system reduces the need for cooling while at the same time boosting the overall solar efficiency of the system, DCS-CHP compares favorably to other electric power generation systems in terms of minimization of water use in the maintenance and operation of the plant. The outlook for water desalination coupled with distributed concentrating solar combined heat and power is less favorable. At a projected cost of 1.40 m-3, water desalination with DCS-CHP would be economical and practical only in areas where water is very scarce or moderately expensive, primarily available through the informal sector, and where contaminated or salt water is easily available as feed-water. It is also interesting to note that 0.40-1.90 m-3 is the range of water prices in the developed world, so DCS-CHP desalination systems could also be an economical solution there under some conditions.

  10. Lunar heat flow: Regional prospective of the Apollo landing sites

    Science.gov (United States)

    Siegler, M. A.; Smrekar, S. E.

    2014-01-01

    reexamine the Apollo Heat Flow Experiment in light of new orbital data. Using three-dimensional thermal conduction models, we examine effects of crustal thickness, density, and radiogenic abundance on measured heat flow values at the Apollo 15 and 17 sites. These models show the importance of regional context on heat flux measurements. We find that measured heat flux can be greatly altered by deep subsurface radiogenic content and crustal density. However, total crustal thickness and the presence of a near-surface radiogenic-rich ejecta provide less leverage, representing only minor (<1.5 mW m-2) perturbations on surface heat flux. Using models of the crust implied by Gravity Recovery and Interior Laboratory results, we found that a roughly 9-13 mW m-2 mantle heat flux best approximate the observed heat flux. This equates to a total mantle heat production of 2.8-4.1 × 1011 W. These heat flow values could imply that the lunar interior is slightly less radiogenic than the Earth's mantle, perhaps implying that a considerable fraction of terrestrial mantle material was incorporated at the time of formation. These results may also imply that heat flux at the crust-mantle boundary beneath the Procellarum potassium, rare earth element, and phosphorus (KREEP) Terrane (PKT) is anomalously elevated compared to the rest of the Moon. These results also suggest that a limited KREEP-rich layer exists beneath the PKT crust. If a subcrustal KREEP-rich layer extends below the Apollo 17 landing site, required mantle heat flux can drop to roughly 7 mW m-2, underlining the need for future heat flux measurements outside of the radiogenic-rich PKT region.

  11. An optimization methodology for the design of renewable energy systems for residential net zero energy buildings with on-site heat production

    DEFF Research Database (Denmark)

    Milan, Christian; Bojesen, Carsten; Nielsen, Mads Pagh

    2011-01-01

    The concept of net zero energy buildings (NZEB) has received increased attention throughout the last years. A well adapted and optimized design of the energy supply system is crucial for the performance of such buildings. This paper aims at developing a method for the optimal sizing of renewable...... energy supply systems for residential NZEB involving on-site production of heat and electricity in combination with electricity exchanged with the public grid. The model is based on linear programming and determines the optimal capacities for each relevant supply technology in terms of the overall system...

  12. Fundamental Study of a Combined Hyperthermia System with RF Capacitive Heating and Interstitial Heating

    OpenAIRE

    Saitoh, Yoshiaki; Hori, Junichi; 斉藤, 義明; 堀, 潤一

    2001-01-01

    Interstitial RF heating with an inserted electrode allows the heating position selection in a subject, but the narrow heating region is problematic. This study elucidates development of new interstitial RF heating methods, combining with external RF heating using paired electrodes, heating the subject broadly in advance in order to selectively extend the heating region. Two kinds of heating system were developed by controlling a differential mode and a common mode of RF currents. Heating expe...

  13. Combined cycles for pipeline compressor drives using heat

    International Nuclear Information System (INIS)

    Malewski, W.F.; Holldorff, G.M.

    1979-01-01

    Combined cycles for pipeline-booster stations using waste heat from gas turbines exhaust can improve the overall efficiency of such stations remarkably. Several working fluids are suitable. Due to existing criteria for selecting a working medium under mentioned conditions, water, ammonia, propane and butane can be considered as practical working fluids. The investigations have shown that: (1) ammonia is advantageous at low exhaust gas and ambient temperatures, (2) water is most effective at high exhaust gas and ambient temperatures, and (3), additionally, hydrocarbons are suitable in a medium range for exhaust gas and condensing temperatures. Not only thermodynamic but also operational features have to be considered. There is not one optimum working fluid but a best one suitable according to the prevailing site conditions

  14. Heat-flow properties of systems with alternate masses or alternate on-site potentials

    Science.gov (United States)

    Pereira, Emmanuel; Santana, Leonardo M.; Ávila, Ricardo

    2011-07-01

    We address a central issue of phononics: the search of properties or mechanisms to manage the heat flow in reliable materials. We analytically study standard and simple systems modeling the heat flow in solids, namely, the harmonic, self-consistent harmonic and also anharmonic chains of oscillators, and we show an interesting insulating effect: While in the homogeneous models the heat flow decays as the inverse of the particle mass, in the chain with alternate masses it decays as the inverse of the square of the mass difference, that is, it decays essentially as the mass ratio (between the smaller and the larger one) for a large mass difference. A similar effect holds if we alternate on-site potentials instead of particle masses. The existence of such behavior in these different systems, including anharmonic models, indicates that it is a ubiquitous phenomenon with applications in the heat flow control.

  15. Combined Steady-State and Dynamic Heat Exchanger Experiment

    Science.gov (United States)

    Luyben, William L.; Tuzla, Kemal; Bader, Paul N.

    2009-01-01

    This paper describes a heat-transfer experiment that combines steady-state analysis and dynamic control. A process-water stream is circulated through two tube-in-shell heat exchangers in series. In the first, the process water is heated by steam. In the second, it is cooled by cooling water. The equipment is pilot-plant size: heat-transfer areas…

  16. Prototype solar heating and combined heating and cooling systems. Quarterly report No. 6

    Energy Technology Data Exchange (ETDEWEB)

    1978-01-06

    The General Electric Company is developing eight prototype solar heating and combined heating and cooling systems. This effort includes development, manufacture, test, installation, maintenance, problem resolution, and performance evaluation.

  17. Combined Heat and Power Dispatch Considering Heat Storage of Both Buildings and Pipelines in District Heating System for Wind Power Integration

    Directory of Open Access Journals (Sweden)

    Ping Li

    2017-06-01

    Full Text Available The strong coupling between electric power and heat supply highly restricts the electric power generation range of combined heat and power (CHP units during heating seasons. This makes the system operational flexibility very low, which leads to heavy wind power curtailment, especially in the region with a high percentage of CHP units and abundant wind power energy such as northeastern China. The heat storage capacity of pipelines and buildings of the district heating system (DHS, which already exist in the urban infrastructures, can be exploited to realize the power and heat decoupling without any additional investment. We formulate a combined heat and power dispatch model considering both the pipelines’ dynamic thermal performance (PDTP and the buildings’ thermal inertia (BTI, abbreviated as the CPB-CHPD model, emphasizing the coordinating operation between the electric power and district heating systems to break the strong coupling without impacting end users’ heat supply quality. Simulation results demonstrate that the proposed CPB-CHPD model has much better synergic benefits than the model considering only PDTP or BTI on wind power integration and total operation cost savings.

  18. From heat integration targets toward implementation – A TSA (total site analysis)-based design approach for heat recovery systems in industrial clusters

    International Nuclear Information System (INIS)

    Hackl, Roman; Harvey, Simon

    2015-01-01

    The European process industry is facing major challenges to decrease production costs. One strategy to achieve this is by increasing energy efficiency. Single chemical processes are often well-integrated and the tools to target and design such measures are well developed. Site-wide heat integration based on total site analysis tools can be used to identify opportunities to further increase energy efficiency. However, the methodology has to be developed further in order to enable identification of practical heat integration measures in a systematic way. Designing site-wide heat recovery systems across an industrial cluster is complex and involves aspects apart from thermal process and utility flows. This work presents a method for designing a roadmap of heat integration investments based on total site analysis. The method is applied to a chemical cluster in Sweden. The results of the case study show that application of the proposed method can achieve up to 42% of the previously targeted hot utility savings of 129 MW. A roadmap of heat integration systems is suggested, ranging from less complex systems that achieve a minor share of the heat recovery potential to sophisticated, strongly interdependent systems demanding large investments and a high level of collaboration. - Highlights: • Methodology focused on the practical implementation of site-wide heat recovery. • Algorithm to determine a roadmap of heat integration investments. • Case study: 42% hot utility savings potential at a pay-back period of 3.9y.

  19. Performance analysis on a new multi-effect distillation combined with an open absorption heat transformer driven by waste heat

    International Nuclear Information System (INIS)

    Zhang, Xiaodong; Hu, Dapeng; Li, Zhiyi

    2014-01-01

    In this paper, a new water distillation system, which consists of either a single- or multi-effect distiller combined with an open absorption heat transformer (OAHT), has been proposed. The new integrated system can be used for distilling waste water with high amounts of SiO 2 from heavy oil production, and the resultant distilled water can be supplied to steam boilers to produce high quality steam which in turn is injected into oil reservoirs to assist with heavy oil recovery. The thermodynamic cycle performances for these new integrated distillation systems were simulated based on the thermodynamic properties of the aqueous solution of LiBr as well as the mass and energy balance of the system. The results indicate that combined with OAHT, the waste heat at 70 °C can be elevated to 125 °C and thereby produce steam at 120 °C in the absorber, which is able to drive a four-effect distiller to produce distilled water. For a single-effect and four-effect distiller, the coefficients of performance (COP) are approximately 1.02 while the performance ratios are 2.19 and 5.72, respectively. Therefore, the four-effect distillation system combined with an OAHT is more thermally effective and is an ideal option to process the waste water in oilfields. -- Highlights: • A new absorption vapor compression distillation was proposed in present research. • An open absorption heat transformer has a coupled thermally evaporator and absorber. • Distillation of waste water with high content of SiO 2 from heavy oil production. • The waste heat of 70 °C can be elevated up to 125 °C and generate steam of 120 °C. • The waste heat is able to drive four-effect distillation to produce distilled water

  20. 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

    2016-01-01

    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.

  1. Evaluating combined effect of noise and heat on blood pressure changes among males in climatic chamber.

    Science.gov (United States)

    Dehghan, Habibollah; Bastami, Mohamad Taghi; Mahaki, Behzad

    2017-01-01

    Exposure to noise and heat causes individuals to experience some changes in the function of cardiovascular system in workplaces. This study aimed to find the combined effect of heat and noise on systolic and diastolic types of blood pressure in experimentally controlled conditions. This quasi-experimental study was performed with 12 male students in a climatic chamber in 2014. Blood pressure including systolic and diastolic was measured in the following conditions: 15 min after rest in exposure to heat (40°C, relative humidity [RH]: 30%), exposure to noise with 75, 85, and 95 dB rates in thermal comfort condition (22.1 ± 0.9 wet-bulb globe temperature), and combined exposure to heat (40°C, RH: 30%) and noise with 75, 85, and 95 dB. Friedman test was used to analyze the data. The mean change of systolic blood pressure was different significantly before and after exposure to heat and noise levels including 75, 85, and 95 dB ( P = 0.015, P = 0.001, P > 0.001, P = 0.027, respectively). Although systolic and diastolic blood pressures changed drastically, it was not significantly different in simultaneous exposure to heat and noise. Both systolic and diastolic blood pressures decreased in exposure to heat, while exposure to different levels of noise elevates systolic and diastolic blood pressures. However, when exposed to a combination of heat and noise, subtle changes of blood pressure were traced, which can be characterized as average, considering heat-only and noise-only tension situations.

  2. Total Site Heat Integration Considering Pressure Drops

    Directory of Open Access Journals (Sweden)

    Kew Hong Chew

    2015-02-01

    Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

  3. Life cycle analysis of distributed concentrating solar combined heat and power: economics, global warming potential and water

    International Nuclear Information System (INIS)

    Norwood, Zack; Kammen, Daniel

    2012-01-01

    We report on life cycle assessment (LCA) of the economics, global warming potential and water (both for desalination and water use in operation) for a distributed concentrating solar combined heat and power (DCS-CHP) system. Detailed simulation of system performance across 1020 sites in the US combined with a sensible cost allocation scheme informs this LCA. We forecast a levelized cost of $0.25 kWh −1 electricity and $0.03 kWh −1 thermal, for a system with a life cycle global warming potential of ∼80 gCO 2 eq kWh −1 of electricity and ∼10 gCO 2 eq kWh −1 thermal, sited in Oakland, California. On the basis of the economics shown for air cooling, and the fact that any combined heat and power system reduces the need for cooling while at the same time boosting the overall solar efficiency of the system, DCS-CHP compares favorably to other electric power generation systems in terms of minimization of water use in the maintenance and operation of the plant. The outlook for water desalination coupled with distributed concentrating solar combined heat and power is less favorable. At a projected cost of $1.40 m −3 , water desalination with DCS-CHP would be economical and practical only in areas where water is very scarce or moderately expensive, primarily available through the informal sector, and where contaminated or salt water is easily available as feed-water. It is also interesting to note that $0.40–$1.90 m −3 is the range of water prices in the developed world, so DCS-CHP desalination systems could also be an economical solution there under some conditions. (letter)

  4. Investigating the combined effects of heat and lighting on students reaction time in laboratory condition

    Directory of Open Access Journals (Sweden)

    Zohre Mohebian

    2016-12-01

    Full Text Available Introduction: In many workplaces there is exposure to heat and light simultaneously. This study investigated the combined effect of heat and lighting on some cognitive performance, i.e. reaction time. Methodology: the present semi-experimental study was conducted 2015 on 33 healthy students (16 girls and 17 boys with a mean age of 22.1 in the thermal stress chamber. The reaction time parameter by the reaction time measurement device, after exposure to different heat surfaces (dry temperatures 22 °C and 37 °C and lighting surfaces (200, 500 and 1500 lux. Data were analyzed using ANOVA test in SPSS-20. Results: The results showed that the average simple, diagnostic, two-color selective, two-sound selective reaction times and reaction time error increased after combined exposure to heat and lighting and showed a significant difference (P<0.05. The maximum score of reaction time belong to temperature of 37 c° and lighting of 1500 lux, the minimum score of reaction time belong to temperature of 22 °c and lighting of 1500 lux.

  5. Combined effect of heat sterilization and ionizing radiation on folacin in canned food

    International Nuclear Information System (INIS)

    Hozova, B.; Sorman, L.

    1986-01-01

    The results are reported of a study in folacin changes following heat sterilization at reduced intensity combined with irradiation of model food products, such as pickled cauliflower and beef in gravy. The folacin content in cauliflower was found to vary with the intensity of heat sterilization; no significant effect was observed of varying radiation doses. With respect to beef in gravy, the study confirmed the suitability of the combined preservation process in view of the higher folacin retention in the given food type. (author). 3 tabs., 14 refs

  6. Heat flow at the proposed Appalachian Ultradeep Core Hole (ADCOH) Site: Tectonic implications

    Science.gov (United States)

    Costain, John K.; Decker, Edward R.

    The heat flow in northwestern South Carolina at the Appalachian Ultradeep Core Hole (ADCOH) site area is approximately 55 mW/m². This data supplements other data to the east in the Piedmont and Atlantic Coastal Plain provinces where heat flows > 55 mW/m² are characteristic of post- and late-synmetamorphic granitoids. Piedmont heat flow and heat generation data for granites, metagranites, and one Slate Belt site, in a zone approximately parallel to major structural Appalachian trends, define a linear relation. Tectonic truncation of heat-producing crust at a depth of about 8 km (a depth equal to the slope of the heat flow-heat production line) is proposed to explain the linear relation. Using the value of reduced heat flow estimated from this empirical relation, and assuming thicknesses of heat-producing crust defined by new ADCOH seismic data, the heat flow and heat production at the ADCOH site are consistent with a depth to the base of the Inner Piedmont crystalline allochthon of about 5.5 km. Seismic data at the ADCOH site confirm that the Inner Piedmont is tectonically truncated at about 5.5 km by the Blue Ridge master decollement. Temperatures at 10 km at the ADCOH site are predicted to be less than 200 °C.

  7. EFFECT OF VIBRATION AND HEAT COMBINATION ON PRIMARY DYSMENORRHEA

    Directory of Open Access Journals (Sweden)

    M. Hoseini

    2015-03-01

    Full Text Available Background: Primary dysmenorrhoea is a common, idiopathic, chronic pelvic pain syndrome, with unknown aetiology which ‎about 50% of women with regular menstrual period suffer. This study was designed to determine the effect of vibration and heat on primary dysmenorrhea. Materials and Methods: In this clinical trial, 75 female students aged 18-22 years old were evaluated for two menstrual cycles. At the first cycle the participants received the routine pain-relief method (synthetic or herbal medicine and traditional remedies. At the second cycle for each participant combined vibration-heat device was applied for ten minutes during ‎menstrual pain. The average of perceived leg pain, lumbar pain and abdominal pain scores at two cycles were determined. The data were analyzed based on Wilcoxon and T tests by using SPSS (v 16.0 for Windows. Results: The average of all perceived pain scores at two cycles were significantly different before pain relief and after both routine methods and using the device (p<0.001. Those were more significantly reduced after using the device in comparison of using routine methods (p<0.001. Conclusion: Since “vibration-heat” is an effective pain relief method, it can be used as a complementary alternative medicine in primary dysmenorrhea reduction.

  8. A feasible system integrating combined heating and power system with ground-source heat pump

    International Nuclear Information System (INIS)

    Li, HongQiang; Kang, ShuShuo; Yu, Zhun; Cai, Bo; Zhang, GuoQiang

    2014-01-01

    A system integrating CHP (combined heating and power) subsystem based on natural gas and GSHP (ground-source heat pump subsystem) in series is proposed. By help of simulation software-Aspen Plus, the energy performance of a typical CHP and GSHP-S (S refers to ‘in series’) system was analyzed. The results show that the system can make a better use of waste heat in flue gas from CHP (combined heating and power subsystem). The total system energy efficiency is 123% and the COP (coefficient of performance) of GSHP (ground-source heat pump) subsystem is 5.3. A referenced CHP and GSHP-P (P refers to ‘in parallel’) system is used for comparison; its total system energy efficiency and COP of GSHP subsystem are 118.6% and 3.5 respectively. Compared with CHP and GSHP-P system with different operating parameters, the CHP and GSHP-S system can increase total system energy efficiency by 0.8–34.7%, with related output ratio of heat to power (R) from 1.9 to 18.3. Furthermore, the COP of GSHP subsystem can be increased between the range 3.6 and 6, which is much higher than that in conventional CHP and GSHP-P system. This study will be helpful for other efficient GSHP systems integrating if there is waste heat or other heat resources with low temperature. - Highlights: • CHP system based on natural gas and ground source heat pump. • The new system can make a better utilization of waste heat in flue gas by a special way. • The proposed system can realize energy saving potential from 0.8 to 34.7%. • The coefficient of performance of ground source heat pump subsystem is significantly improved from 3.5 to 3.6–6. • Warm water temperature and percentage of flue gas used to reheat are key parameters

  9. A combined thermodynamic cycle used for waste heat recovery of internal combustion engine

    International Nuclear Information System (INIS)

    He, Maogang; Zhang, Xinxin; Zeng, Ke; Gao, Ke

    2011-01-01

    In this paper, we present a steady-state experiment, energy balance and exergy analysis of exhaust gas in order to improve the recovery of the waste heat of an internal combustion engine (ICE). Considering the different characteristics of the waste heat of exhaust gas, cooling water, and lubricant, a combined thermodynamic cycle for waste heat recovery of ICE is proposed. This combined thermodynamic cycle consists of two cycles: the organic Rankine cycle (ORC), for recovering the waste heat of lubricant and high-temperature exhaust gas, and the Kalina cycle, for recovering the waste heat of low-temperature cooling water. Based on Peng–Robinson (PR) equation of state (EOS), the thermodynamic parameters in the high-temperature ORC were calculated and determined via an in-house computer program. Suitable working fluids used in high-temperature ORC are proposed and the performance of this combined thermodynamic cycle is analyzed. Compared with the traditional cycle configuration, more waste heat can be recovered by the combined cycle introduced in this paper. -- Highlights: ► We study the energy balance of fuel in internal combustion engine. ► Heat recovery effect of exhaust gas is good when ICE is at a high-load condition. ► We propose a new combined thermodynamic cycle for waste heat of ICE. ► The combined cycle has a higher recovery efficiency than previous configurations.

  10. Combined heat and power production through biomass gasification with 'Heatpipe-Reformer'

    International Nuclear Information System (INIS)

    Iliev, I.; Kamburova, V.; Terziev, A.

    2013-01-01

    The current report aims is to analyze the system for combined heat and power production through biomass gasification with “heatpipe-reformer” system. Special attention is paid on the process of synthetic gas production in the Reformer, its cleaning and further burning in the co-generation unit. A financial analysis is made regarding the investments and profits generated by the combined heat and power production. (authors)

  11. Measure Guideline. Combination Forced-Air Space and Tankless Domestic Hot Water Heating Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation Industry Team (BSC), Somerville, MA (United States)

    2012-08-01

    This document describes design and application guidance for combination space and tankless domestic hot water heating systems (combination systems) used in residential buildings, based on field evaluation, testing, and industry meetings conducted by Building Science Corporation. As residential building enclosure improvements continue to drive heating loads down, using the same water heating equipment for both space heating and domestic water heating becomes attractive from an initial cost and space-saving perspective. This topic is applicable to single- and multi-family residential buildings, both new and retrofitted.

  12. Biomass Supply Planning for Combined Heat and Power Plants using Stochastic Programming

    DEFF Research Database (Denmark)

    Guericke, Daniela; Blanco, Ignacio; Morales González, Juan Miguel

    method using stochastic optimization to support the biomass supply planning for combined heat and power plants. Our two-phase approach combines mid-term decisions about biomass supply contracts with the short-term decisions regarding the optimal market participation of the producer to ensure......During the last years, the consumption of biomass to produce power and heat has increased due to the new carbon neutral policies. Nowadays, many district heating systems operate their combined heat and power (CHP) plants using different types of biomass instead of fossil fuel, especially to produce......, and heat demand and electricity prices vary drastically during the planning period. Furthermore, the optimal operation of combined heat and power plants has to consider the existing synergies between the power and heating systems while always fulfilling the heat demand of the system. We propose a solution...

  13. Irradiation in combination of heat treatment of mango puree

    International Nuclear Information System (INIS)

    Noomhorm, A.; Apintanapong, M.

    1996-01-01

    The effect of irradiation with heat combination treatment on the shelf life and quality of mango puree was studied. Thermal inactivation of polyphenol oxidase enzyme at 80 degree C and 15 min. was used as a measure of adequacy of pre-heat treatment. Irradiation of mango puree after heat treatment at dosage of 0, 2, 4, 6 and 8 kGy showed no change in mc, pH, acidity, and TSS but during storage, growth of microorganisms brought changes in these values. Irradiation in combination with low temperature (5 degree C) reduced discoloration and darkening rate during storage. Irradiation dose from 0 to 8 kGy resulted in log linear reductions in microorganism levels but at 6 and 8 kGy, there was no growth of microorganisms. Products irradiated at 8 kGy showed no microorganism growth at both temperatures

  14. Performance characteristics of a combination solar photovoltaic heat engine energy converter

    Science.gov (United States)

    Chubb, Donald L.

    1987-01-01

    A combination solar photovoltaic heat engine converter is proposed. Such a system is suitable for either terrestrial or space power applications. The combination system has a higher efficiency than either the photovoltaic array or the heat engine alone can attain. Advantages in concentrator and radiator area and receiver mass of the photovoltaic heat engine system over a heat-engine-only system are estimated. A mass and area comparison between the proposed space station organic Rankine power system and a combination PV-heat engine system is made. The critical problem for the proposed converter is the necessity for high temperature photovoltaic array operation. Estimates of the required photovoltaic temperature are presented.

  15. Flexibility of a combined heat and power system with thermal energy storage for district heating

    International Nuclear Information System (INIS)

    Nuytten, Thomas; Claessens, Bert; Paredis, Kristof; Van Bael, Johan; Six, Daan

    2013-01-01

    Highlights: ► A generic model for flexibility assessment of thermal systems is proposed. ► The model is applied to a combined heat and power system with thermal energy storage. ► A centrally located storage offers more flexibility compared to individual units. ► Increasing the flexibility requires both a more powerful CHP and a larger buffer. - Abstract: The trend towards an increased importance of distributed (renewable) energy resources characterized by intermittent operation redefines the energy landscape. The stochastic nature of the energy systems on the supply side requires increased flexibility at the demand side. We present a model that determines the theoretical maximum of flexibility of a combined heat and power system coupled to a thermal energy storage solution that can be either centralized or decentralized. Conventional central heating, to meet the heat demand at peak moments, is also available. The implications of both storage concepts are evaluated in a reference district. The amount of flexibility created in the district heating system is determined by the approach of the system through delayed or forced operation mode. It is found that the distinction between the implementation of the thermal energy storage as a central unit or as a collection of local units, has a dramatic effect on the amount of available flexibility

  16. Heat transfer in a sodium-to-sodium heat exchanger under conditions of combined force and free convection

    International Nuclear Information System (INIS)

    Jackson, J.D.; Axcell, B.P.; Johnston, S.E.

    1987-01-01

    A combined experimental and theoretical investigation of heat transfer in a vertical tube and annulus, countercurrent flow heat exchanger is reported. The working fluid was liquid sodium. Included in the range of conditions covered were those which are of interest in connection with the low flow rate operation of fast reactor intermediate heat exchanger systems. The heat transfer process ranged from that of pure forced convection to combined forced and free convection. By changing the direction of fluid flow or the direction of heat flow four different configurations were studied. In two cases the convection process was buoyancy aided and in the other two it was buoyancy opposed. Results are presented showing the influence of flow rate and temperature difference on overall heat transfer coefficient for each case. A theoretical model of turbulent flow and heat transfer incorporating influences of buoyancy was used to produce results for the range of conditions covered in the experiments. The predictions of overall heat transfer coefficient were found to be in reasonable general agreement with the measurements. It was clear from these calculations that the influence of buoyancy on heat transfer stemmed largely, under the conditions of the present experiment, from the modification of the convection process due to the distortion of the velocity field. This led to an enhancement of the heat transfer for the buoyancy-aided process and an impairment for the buoyancy-opposed process. The contribution of the turbulent diffusion of heat was relatively small. (author)

  17. Evaluation of alternatives of exothermic methanization cycle for combined electricity and heat generation

    International Nuclear Information System (INIS)

    Balajka, J.; Princova, H.

    1987-01-01

    The possibilities are discussed of using the ADAM-EVA system for remote heat supply from nuclear heat sources to district heating systems. Attention is devoted to the use of the exothermal methanization process (ADAM station) for the combined power and heat production, this making use of the existing hot water power distribution network. The basic parameter for the evaluation of the over-all efficiency of the combined power and heat production is the maximum methanization cycle temperature which depends on the life of the methanization catalyst. Upon temperature drop below 550 degC, the conversion process can only be secured by means of two-stage methanization, which leads to a simplification of the cycle and a reduction in investment cost. At a temperature lower than 500 degC, combined power and heat production cannot be implemented. On the contrary, a considerable amount of electric power supplied from outside the system would be needed for compression work. (Z.M.)

  18. Some Problems of the Integration of Heat Pump Technology into a System of Combined Heat and Electricity Production

    Directory of Open Access Journals (Sweden)

    G. Böszörményi

    2001-01-01

    Full Text Available The closure of a part of the municipal combined heat and power (CHP plant of Košice city would result in the loss of 200 MW thermal output within a realtively short period of time. The long term development plan for the Košice district heating system concentrates on solving this problem. Taking into account the extremely high (90 % dependence of Slovakia on imported energy sources and the desirability of reducing the emission of pollutantst the alternative of supplying of 100 MW thermal output from geothermal sources is attractive. However the indices of economic efficiency for this alternative are unsatisfactory. Cogeneration of electricity and heat in a CHP plant, the most efficient way of supplying heat to Košice at the present time. If as planned, geothermal heat is fed directly into the district heating network the efficiency would be greatly reduced. An excellent solution of this problem would be a new conception, preferring the utilization of geothermal heat in support of a combined electricity and heat production process. The efficiency of geothermal energy utilization could be increased through a special heat pump. This paper deals with several aspects of the design of a heat pump to be integrated into the system of the CHP plant.

  19. Base-Load and Peak Electricity from a Combined Nuclear Heat and Fossil Combined-Cycle Plant

    International Nuclear Information System (INIS)

    Conklin, Jim; Forsberg, Charles W.

    2007-01-01

    A combined-cycle power plant is proposed that uses heat from a high-temperature reactor and fossil fuel to meet base-load and peak electrical demands. The high-temperature gas turbine produces shaft power to turn an electric generator. The hot exhaust is then fed to a heat recovery steam generator (HRSG) that provides steam to a steam turbine for added electrical power production. A simplified computational model of the thermal power conversion system was developed in order to parametrically investigate two different steady-state operation conditions: base load nuclear heat only from an Advanced High Temperature Reactor (AHTR), and combined nuclear heat with fossil heat to increase the turbine inlet temperature. These two cases bracket the expected range of power levels, where any intermediate power level can result during electrical load following. The computed results indicate that combined nuclear-fossil systems have the potential to offer both low-cost base-load electricity and lower-cost peak power relative to the existing combination of base-load nuclear plants and separate fossil-fired peak-electricity production units. In addition, electric grid stability, reduced greenhouse gases, and operational flexibility can also result with using the conventional technology presented here for the thermal power conversion system coupled with the AHTR

  20. Large-Scale Combined Heat and Power (CHP) Generation at Loviisa Nuclear Power Plant Unit 3

    International Nuclear Information System (INIS)

    Bergroth, N.

    2010-01-01

    Fortum has applied for a Decision in Principle concerning the construction of a new nuclear power plant unit (Loviisa 3) ranging from 2800-4600 MWth at its site located at the southern coast of Finland. An attractive alternative investigated is a co-generation plant designed for large-scale district heat generation for the Helsinki metropolitan area that is located approximately 75 km west of the site. The starting point is that the district heat generation capacity of 3 unit would be around 1 000 MWth.The possibility of generating district heat for the metropolitan area by Loviisa's two existing nuclear power plant units was investigated back in the 1980s, but it proved unpractical at the time. With the growing concern of the climate change and the subsequent requirements on heat and power generation, the idea is much more attractive today, when recognising its potential to decrease Finland's carbon dioxide emissions significantly. Currently the district heat generation in metropolitan area is based on coal and natural gas, producing some five to seven million tonnes of carbon dioxide emissions annually. Large-scale combined heat and power (CHP) generation at the 3 unit could cut this figure by up to four million tonnes. This would decrease carbon dioxide emissions by as much as six percent. In addition, large-scale CHP generation would increase the overall efficiency of the new unit significantly and hence, reduce the environmental impact on the local marine environment by cutting heat discharges into the Gulf of Nuclear energy has been used for district heating in several countries both in dedicated nuclear heating plants and in CHP generation plants. However, the heat generation capacity is usually rather limited, maximum being around 250 MWth per unit. Set against this, the 3 CHP concept is much more ambitious, not only because of the much larger heat generation output envisaged, but also because the district heating water would have to be transported over a

  1. Combined installation of electric and heat supply for climatic conditions of Iraq

    Science.gov (United States)

    Kaisi, Osama Al; Sidenkov, D. V.

    2017-11-01

    Electricity, heating and cooling are the three main components that make up the energy consumption base in residential, commercial and public buildings around the world. Demand for energy and fuel costs are constantly growing. Combined cooling, heating and power generation or trigeneration can be a promising solution to such a problem, providing an efficient, reliable, flexible, competitive and less harmful alternative to existing heat and cold supply systems. In this paper, scheme of the tri-generation plant on non-aqueous working substances is considered as an installation of a locally centralized electro-heat and cold supply of a typical residential house in a hot climate. The scheme of the combined installation of electro-heat (cold) supply consisted of the vapor power plant and heat pump system on low-boiling working substance for local consumers under the climatic conditions of Iraq is presented. The possibility of using different working substances in the thermodynamic cycles of these units, which will provide better efficiency of such tri-generation systems is shown. The calculations of steam turbine cycles and heat pump part on the selected working substances are conducted. It is proposed to use heat exchangers of plate type as the main exchangers in the combined processing. The developed method of thermal-hydraulic calculation of heat exchangers implemented in MathCad, which allows to evaluate the efficiency of plants of this type using the ε - NTU method. For the selected working substances of the steam part the optimal temperature of heat supply to the steam generator is determined. The results of thermodynamic and technical-economic analysis of the application of various working substances in the “organic” Rankine cycle of the steam turbine unit and the heat pump system of the heat and cold supply system are presented.

  2. Waste heat of HTR power stations for district heating

    International Nuclear Information System (INIS)

    Bonnenberg, H.; Schlenker, H.V.

    1975-01-01

    The market situation, the applied techniques, and the transport, for district heating in combination with HTR plants are considered. Analysis of the heat market indicates a high demand for heat at temperatures between 100 and 150 0 C in household and industry. This market for district heating can be supplied by heat generated in HTR plants using two methods: (1) the combined heat and power generation in steam cycle plants by extracting steam from the turbine, and (2) the use of waste heat of a closed gas turbine cycle. The heat generation costs of (2) are negligible. The cost for transportation of heat over the average distance between existing plant sites and consumer regions (25 km) are between 10 and 20% of the total heat price, considering the high heat output of nuclear power stations. Comparing the price of heat gained by use of waste heat in HTR plants with that of conventional methods, considerable advantages are indicated for the combined heat and power generation in HTR plants. (author)

  3. Preservation of canned Vienna sausage by combination of heat and radiation

    International Nuclear Information System (INIS)

    Incze, K.; Farkas, J.; Zukal, E.

    1973-01-01

    Since no texture improver is permitted in Hungarian Vienna sausage, the heat treatment necessary for bacteriological safety causes texture and consistency problems with this type of product. The aim of the investigations was to lower the heat damage by using a combination of mild heat treatment and irradiation. During the experiments an irradiation dose of 0.45 Mrad was combined with heat treatments of various F 0 values (0.2-0.5). F 0 of the control was 1.9. Naturally contaminated samples were used. Storage temperature was 30 0 C, storage time up to 2 months. Combination of irradiation (0.45 Mrad) and heat treatment (F 0 =0.4) - regardless of the sequence - gave satisfactory results in shelf-life and excellent results in organoleptic properties as compared to traditionally heat treated samples. This statement is valid for uninoculated samples only. (F.J.)

  4. Effect of nitrite on the microbiological stability of canned Vienna sausages preserved by mild heat treatment or combinations of heat and irradiation

    International Nuclear Information System (INIS)

    Farkas, J.; Zukal, E.; Incze, K.

    1973-01-01

    Keeping quality of Vienna sausages packed in No. 1/5 cans (ca 200 g) with salt brine and heat treated with F 0 values in the range of 0.25-0.55 was studied as a function of sodium nitrate addition. In uninoculated cans the heat requirement of preservation proved to be about 0.3 F 0 in the presence of 300 ppm NaNO 2 . A heat treatment of 0.55 F 0 and 200 ppm NaNO 2 resulted in higher microbiological stability of cans inoculated with 2x10 4 /tin Clostridium sporogenes spores than a heat treatment of 1.9 F 0 without nitrite addition. The effect of the combination of heat treatment of 0.35-0.55 F 0 and 0.45 Mrad of gamma irradiation was also studied with inoculated cans. The combination of irradiation plus heat resulted in a higher microbiological stability of the samples than the reversed order of the treatments, but this synergistic effect could not be proved in all experiments. The addition of 200 ppm NaNO 2 was not as effective in increasing the shelf-life of combination treated samples as with the solely heat treated ones. In a medium composed of a 50% extract of Vienna sausages (pH 6.4, asub(w) 0.96) and inoculated with 10 5 per ml Clostridium sporogenes spores 100 ppm or more NaNO 2 was required to ensure microbiological stability of samples heat treated with F 0 0.4. In the range of the permitted concentration level for canned meat products, sodium nitrite did not influence the heat resistance of Clostridium sporogenes, but inhibited the germination of the surviving spores. (F.J.)

  5. Hydrothermal regime and constraints on reservoir depth of the Jade site in the Mid-Okinawa Trough inferred from heat flow measurements

    Science.gov (United States)

    Kinoshita, Masataka; Yamano, Makoto

    1997-02-01

    Detailed heat flow measurements revealed an enormous heat flow variation (102 to 105 mW m-2) in the Jade hydrothermal field (27°16'N, 127°05'E and water depth 1350 m) located on the slope of the Izena Hole in the Mid-Okinawa Trough. Within the Jade site, heat flow is higher than 1000 mW m-2 and decreases to ˜100 mW m-2 with a 1 km horizontal scale. Near the Jade black smoker, heat flow varies from >30,000 mW m-2 at a hydrothermally altered area to 1700 mW m-2 less than 100 m from it. A large-scale heat flow variation suggests that the base of the escarpment near the Jade site serves as a recharge area for the Jade site. Linear geotherms indicate that the upward Darcian flow within sediments is slower than ˜3 cm yr-1. Thus the fluid circulation pathways would basically be restricted in permeable channels. Estimated conductive heat output rate from the Jade site is 4-7 MW, which is comparable to heat output by a single black smoker vent (˜8 MW). One-dimensional thermal modeling predicts the existence of a boiling zone at ˜200 m beneath the Jade site, which may be overlain by a fractured impermeable layer. The normal chloride content of venting fluids from the black smoker may be explained either by upwelling of fluid which boiled at shallow depth but suffered no phase segregation, or by upwelling of fluid above the boiling interface.

  6. Thermal Energy Corporation Combined Heat and Power Project

    Energy Technology Data Exchange (ETDEWEB)

    Turner, E. Bruce [Thermal Energy Corporation, Houston, TX (United States); Brown, Tim [Thermal Energy Corporation, Houston, TX (United States); Mardiat, Ed [Burns and McDonnell Engineering Company, Inc., Kansas City, MI (United States)

    2011-12-31

    To meet the planned heating and cooling load growth at the Texas Medical Center (TMC), Thermal Energy Corporation (TECO) implemented Phase 1 of a Master Plan to install an additional 32,000 tons of chilled water capacity, a 75,000 ton-hour (8.8 million gallon) Thermal Energy Storage (TES) tank, and a 48 MW Combined Heat and Power (CHP) system. The Department of Energy selected TMC for a $10 million grant award as part of the Financial Assistance Funding Opportunity Announcement, U.S. Department of Energy National Energy Technology, Recovery Act: Deployment of Combined Heat and Power (CHP) Systems, District Energy Systems, Waste Energy Recovery Systems, and Efficiency Industrial Equipment Funding Opportunity Number: DE-FOA-0000044 to support the installation of a new 48 MW CHP system at the TMC located just outside downtown Houston. As the largest medical center in the world, TMC is home to many of the nation's best hospitals, physicians, researchers, educational institutions, and health care providers. TMC provides care to approximately six million patients each year, and medical instruction to over 71,000 students. A medical center the size of TMC has enormous electricity and thermal energy demands to help it carry out its mission. Reliable, high-quality steam and chilled water are of utmost importance to the operations of its many facilities. For example, advanced medical equipment, laboratories, laundry facilities, space heating and cooling all rely on the generation of heat and power. As result of this project TECO provides this mission critical heating and cooling to TMC utilizing a system that is both energy-efficient and reliable since it provides the capability to run on power independent of the already strained regional electric grid. This allows the medical center to focus on its primary mission providing top quality medical care and instruction without worrying about excessive energy costs or the loss of heating and cooling due to the risk of power

  7. Municipal Development of Anaerobic Digestion/ Combined Heat and Power in Massachusetts

    Science.gov (United States)

    Pike, Brenda

    With a commercial food waste ban going into effect in Massachusetts in October 2014, businesses, institutions, and municipalities are considering alternatives to landfills and incinerators for organic waste. Anaerobic digestion is one such alternative. Similar to composting, but in an environment devoid of oxygen, anaerobic digestion produces byproducts such as methane (which can be burned for heat or electricity) and liquid or solid digestate (which can be used as fertilizer, cattle bedding, and more). Thus, disposal of food waste and other organic materials can become a source of revenue rather than just an expense. Municipalities interested in developing anaerobic digestion/combined heat and power (AD/CHP) facilities have the benefit of desirable options for sites, such as landfill gas facilities and wastewater treatment plants, and potential feedstocks in source-separated residential or municipal food waste or wastewater. This thesis examines the opportunities and challenges for municipal development of AD/CHP facilities in Massachusetts.

  8. Effect of radiant heat at the birth site in farrowing crates on hypothermia and behaviour in neonatal piglets

    DEFF Research Database (Denmark)

    Andersen, Heidi Mai-Lis; Pedersen, Lene Juul

    2016-01-01

    It has been documented that floor heating of the farrowing area in loose housed sows improves survival of piglets significantly. However, today, the majority of farrowing pens are designed with crating of sows and slatted floor at the birth site. The aim of this study was to investigate whether...... providing radiant heat at the birth site to new-born piglets in pens with crated sows reduced hypothermia, time to first milk intake and growth of the piglets during the 1st week. Second parity Danish Landrace×Yorkshire sows (n=36) were randomly divided into two groups: Control (CG) and heat (HG......). In the area behind the sow (zone 1), two radiant heat panels were mounted above the slatted floor in the HG. The farrowings were attended, and the heaters were turned on at birth of first piglet and turned off 12 h after. Birth time, time to leave zone 1, time to first contact with udder and time to first...

  9. An engineering-economic analysis of combined heat and power technologies in a (mu)grid application

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Owen; Ouaglal, Boubekeur; Bartholomew, Emily; Marnay, Chris; Bourassa, Norman

    2002-03-01

    This report describes an investigation at Ernesto Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) of the potential for coupling combined heat and power (CHP) with on-site electricity generation to provide power and heating, and cooling services to customers. This research into distributed energy resources (DER) builds on the concept of the microgrid (mGrid), a semiautonomous grouping of power-generating sources that are placed and operated by and for the benefit of its members. For this investigation, a hypothetical small shopping mall (''Microgrid Oaks'') was developed and analyzed for the cost effectiveness of installing CHP to provide the mGrid's energy needs. A mGrid consists of groups of customers pooling energy loads and installing a combination of generation resources that meets the particular mGrid's goals. This study assumes the mGrid is seeking to minimize energy costs. mGrids could operate independently of the macrogrid (the wider power network), but they are usually assumed to be connected, through power electronics, to the macrogrid. The mGrid in this study is assumed to be interconnected to the macrogrid, and can purchase some energy and ancillary services from utility providers.

  10. Effects of the distribution density of a biomass combined heat and power plant network on heat utilisation efficiency in village-town systems.

    Science.gov (United States)

    Zhang, Yifei; Kang, Jian

    2017-11-01

    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

  11. The role of policy instruments for promoting combined heat and power production with low CO2 emissions in district heating systems

    International Nuclear Information System (INIS)

    Marbe, A.; Harvey, S.

    2005-01-01

    Policy instruments clearly influence the choice of production technologies and fuels in large energy systems, including district heating networks. Current Swedish policy instruments aim at promoting the use of biofuel in district heating systems, and at promoting electric power generation from renewable energy sources. However, there is increasing pressure to harmonize energy policy instruments within the EU. In addition, natural gas based combined cycle technology has emerged as the technology of choice in the power generation sector in the EU. This study aims at exploring the role of policy instruments for promoting the use of low CO 2 emissions fuels in high performance combined heat and power systems in the district heating sector. The paper presents the results of a case study for a Swedish district heating network where new large size natural gas combined cycle (NGCC) combined heat and power (CHP) is being built. Given the aim of current Swedish energy policy, it is assumed that it could be of interest in the future to integrate a biofuel gasifier to the CHP plant and co-fire the gasified biofuel in the gas turbine unit, thereby reducing usage of fossil fuel. The goals of the study are to evaluate which policy instruments promote construction of the planned NGCC CHP unit, the technical performance of an integrated biofuelled pressurized gasifier with or without dryer on plant site, and which combination of policy instruments promote integration of a biofuel gasifier to the planned CHP unit. The power plant simulation program GateCycle was used for plant performance evaluation. The results show that current Swedish energy policy instruments favour investing in the NGCC CHP unit. The corresponding cost of electricity (COE) from the NGCC CHP unit is estimated at 253 SEK MWh -1 , which is lower than the reference power price of 284 SEK MWh -1 . Investing in the NGCC CHP unit is also shown to be attractive if a CO 2 trading system is implemented. If the value of

  12. Combined convective heat transfer of liquid sodium flowing across tube banks

    International Nuclear Information System (INIS)

    Ma, Ying; Sugiyama, Ken-ichiro; Ishiguro, Ryoji

    1989-01-01

    In order to clarify the heat transfer characteristics of combined convection of liquid sodium, a numerical analysis is performed for liquid sodium which flows through a single horizontal row of tubes in the direction of gravity. The correlation of heat transfer characteristics between liquid sodium and ordinary fluids is also discussed. The heat transfer characteristics at large Reynolds numbers are improved when the Richardson number is increased, and the improvement rate is enlarged with increase in p/d value, since convection effect is relatively large. However heat transfer coefficients do not differ from those of forced convection at small Reynolds numbers even when the Richardson number reaches a high value because of conduction effect. A good consistence of heat transfer characteristics of combined convection between liquid sodium and air is obtained at the same Peclet number and Richardson number. This means that the fundamental heat transfer characteristics of combined convection of liquid sodium can be investigated with ordinary fluids. (author)

  13. Characterization of the geology, geochemistry, and microbiology of the radio frequency heating demonstration site at the Savannah River Site

    International Nuclear Information System (INIS)

    Eddy Dilek, C.A.; Jarosch, T.R.; Fliermans, C.B.; Looney, B.B.; Parker, W.H.

    1993-08-01

    The overall objective of the Integrated Demonstration Project for the Remediation of Organics at Nonarid Sites at the Savannah River Site (SRS) is to evaluate innovative remediation, characterization, and monitoring systems to facilitate restoration of contaminated sites. The first phase of the demonstration focused on the application and development of in situ air stripping technologies to remediate sediments and groundwater contaminated with volatile organic compounds (VOCs). The second phase focused on the enhancement of the in situ air stripping process by adding selected nutrients to stimulate naturally occurring microorganisms that degrade VOCs. The purpose of the third phase was to evaluate the use of heating technologies [radio frequency (rf) and ohmic heating] to enhance the removal of contamination from clay layers where mass transfer is limited. The objective of this report is to document pretest and post-test data collected in support of the rf heating demonstration. The following data are discussed in this report: (1) a general description of the site including piezometers and sensors installed to monitor the remedial process; (2) stratigraphy, lithology, and a detailed geologic cross section of the study site; (3) tabulations of pretest and post-test moisture and VOC content of the sediments; (4) sampling and analysis procedures for sediment samples; (5) microbial abundance and diversity; (6) three-dimensional images of pretest and post-test contaminant distribution; (7) volumetric calculations

  14. Preliminary analysis of effects of thermal loading on gas and heat flow within the framework of the LBNL/USGS site-scale model

    International Nuclear Information System (INIS)

    Wu, Y.S.; Chen, G.; Bodvarsson, G.

    1995-12-01

    The US Department of Energy is performing detailed site characterization studies at Yucca Mountain to determine its suitability as a geological repository site for high level nuclear wastes. As part of these research efforts, a three-dimensional, site-scale unsaturated-zone model has been developed at Lawrence Berkeley National Laboratory (LBNL) in collaboration with the US Geological Survey (USGS). The primary objectives of developing the 3-D site-scale model are to predict the ambient hydrogeological conditions and the movement of moisture and gas within the unsaturated zone of the mountain. In addition, the model has the capability of modeling non-isothermal flow and transport phenomena at the mountain. Applications of such a site-scale model should include evaluation of effects of thermal loading on heated gas and heat flow through the mountain for long-term performance assessment of the repository. Emplacement of heat-generating, high-level nuclear wastes at Yucca Mountain would create complex multiphase fluid flow and heat transfer processes. The physical mechanisms include conductive and convective heat transfer, phase change phenomena (vaporization and condensation), flow of liquid and gas phases under variably-saturated condition, diffusion and dispersion of vapor and gas, vapor sorption, and vapor-pressure lowering effects. The heterogeneity of complicated geological setting at Yucca Mountain, such as alternating, layers of porous-fractured rocks, will significantly affect the processes of fluid and heat flow

  15. A combined thermodynamic cycle based on methanol dissociation for IC (internal combustion) engine exhaust heat recovery

    International Nuclear Information System (INIS)

    Fu, Jianqin; Liu, Jingping; Xu, Zhengxin; Ren, Chengqin; Deng, Banglin

    2013-01-01

    In this paper, a novel approach for exhaust heat recovery was proposed to improve IC (internal combustion) engine fuel efficiency and also to achieve the goal for direct usage of methanol as IC engine fuel. An open organic Rankine cycle system using methanol as working medium is coupled to IC engine exhaust pipe for exhaust heat recovery. In the bottom cycle, the working medium first undergoes dissociation and expansion processes, and is then directed back to IC engine as fuel. As the external bottom cycle and the IC engine main cycle are combined together, this scheme forms a combined thermodynamic cycle. Then, this concept was applied to a turbocharged engine, and the corresponding simulation models were built for both of the external bottom cycle and the IC engine main cycle. On this basis, the energy saving potential of this combined cycle was estimated by parametric analyses. Compared to the methanol vapor engine, IC engine in-cylinder efficiency has an increase of 1.4–2.1 percentage points under full load conditions, while the external bottom cycle can increase the fuel efficiency by 3.9–5.2 percentage points at the working pressure of 30 bar. The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points. - Highlights: • A combined thermodynamic cycle using methanol as working medium for IC engine exhaust heat recovery is proposed. • The external bottom cycle of exhaust heat recovery and IC engine working cycle are combined together. • IC engine fuel efficiency could be improved from both in-cylinder working cycle and external bottom cycle. • The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points at full load

  16. The effect of the combined treatment of gamma irradiation and heating on the aerobic bacterial load of white and black peppers

    International Nuclear Information System (INIS)

    Mohd Khan Ayob; Ismail Bahari; Osman Hassan; Verumandy Kaleswaran

    1985-01-01

    The effect of combined heat-irradiation treatment on the aerobic bacterial load of black and white peppers were evaluated in comparison with that of heat or irradiation treatment only. The irradiation doses applied were 0 (control), 2, 4, 6 and 8 kGy and the heating temperatures were 28 (control), 50, 60, 70 and 80 deg C. Results indicated that gamma radiation of 7 kGy and 5 kGy were capable of reducing bacterial population from 3.6 x 10 6 /g and 2.9 x 10 5 /g to 3 /g black and white peppers, respectively. Heating at drying temperature could only reduce the bacterial contaminants to 1/2 log cycle. Combined treatment of irradiation followed by heating is more effective in reducing the bacterial load, and the combined treatment of heating followed by irradiation showed similar effects as in irradiation treatment alone. (author)

  17. Development of shelf stable, processed, low acid food products using heat-irradiation combination treatments

    International Nuclear Information System (INIS)

    Minnaar, A.

    1998-01-01

    The amount of ionizing irradiation needed to sterilize low acid vegetable and starch products (with and without sauces) commercially impairs their sensorial and nutritive qualities, and use of thermal processes for the same purpose may also have an adverse effect on the product quality. A systematic approach to the establishment of optimized combination parameters was developed for heat-irradiation processing to produce high quality, shelf stable, low acid food products. The effects of selected heat, heat-irradiation combination and irradiation treatments on the quality of shelf stable mushrooms in brine and rice, stored at ambient temperature, were studied. From a quality viewpoint, use of heat-irradiation combination treatments favouring low irradiation dose levels offered a feasible alternative to thermally processed or radappertized mushrooms in brine. However, shelf stable rice produced by heat-irradiation combination treatments offered a feasible alternative only to radappertized rice from the standpoint of quality. The technical requirements for the heat and irradiation processing of a long grain rice cultivar from the United States of America oppose each other directly, thereby reducing the feasibility of using heat-irradiation combination processing to produce shelf stable rice. The stability of starch thickened white sauces was found to be affected severely during high dose irradiation and subsequent storage at ambient temperature. However, use of pea protein isolate as a thickener in white sauces was found to have the potential to maintain the viscosity of sauces for irradiated meat and sauce products throughout processing and storage. (author)

  18. Relative contributions of microbial and infrastructure heat at a crude oil-contaminated site

    Science.gov (United States)

    Warren, Ean; Bekins, Barbara A.

    2018-04-01

    Biodegradation of contaminants can increase the temperature in the subsurface due to heat generated from exothermic reactions, making temperature observations a potentially low-cost approach for determining microbial activity. For this technique to gain more widespread acceptance, it is necessary to better understand all the factors affecting the measured temperatures. Biodegradation has been occurring at a crude oil-contaminated site near Bemidji, Minnesota for 39 years, creating a quasi-steady-state plume of contaminants and degradation products. A model of subsurface heat generation and transport helps elucidate the contribution of microbial and infrastructure heating to observed temperature increases at this site. We created a steady-state, two-dimensional, heat transport model using previous-published parameter values for physical, chemical and biodegradation properties. Simulated temperature distributions closely match the observed average annual temperatures measured in the contaminated area at the site within less than 0.2 °C in the unsaturated zone and 0.4 °C in the saturated zone. The model results confirm that the observed subsurface heat from microbial activity is due primarily to methane oxidation in the unsaturated zone resulting in a 3.6 °C increase in average annual temperature. Another important source of subsurface heat is from the active, crude-oil pipelines crossing the site. The pipelines impact temperatures for a distance of 200 m and contribute half the heat. Model results show that not accounting for the heat from the pipelines leads to overestimating the degradation rates by a factor of 1.7, demonstrating the importance of identifying and quantifying all heat sources. The model results also highlighted a zone where previously unknown microbial activity is occurring at the site.

  19. Modelling the viability of heat recovery from combined sewers.

    Science.gov (United States)

    Abdel-Aal, M; Smits, R; Mohamed, M; De Gussem, K; Schellart, A; Tait, S

    2014-01-01

    Modelling of wastewater temperatures along a sewer pipe using energy balance equations and assuming steady-state conditions was achieved. Modelling error was calculated, by comparing the predicted temperature drop to measured ones in three combined sewers, and was found to have an overall root mean squared error of 0.37 K. Downstream measured wastewater temperature was plotted against modelled values; their line gradients were found to be within the range of 0.9995-1.0012. The ultimate aim of the modelling is to assess the viability of recovering heat from sewer pipes. This is done by evaluating an appropriate location for a heat exchanger within a sewer network that can recover heat without impacting negatively on the downstream wastewater treatment plant (WWTP). Long sewers may prove to be more viable for heat recovery, as heat lost can be reclaimed before wastewater reaching the WWTP.

  20. Combination study of operation characteristics and heat transfer mechanism for pulsating heat pipe

    International Nuclear Information System (INIS)

    Cui, Xiaoyu; Zhu, Yue; Li, Zhihua; Shun, Shende

    2014-01-01

    Pulsating heat pipe (PHP) is becoming a promising heat transfer device for the application like electronics cooling. However, due to its complicated operation mechanism, the heat transfer properties of the PHP still have not been fully understood. This study experimentally investigated on a closed-loop PHP charged with four types of working fluids, deionized water, methanol, ethanol and acetone. Combined with the visualization experimental results from the open literature, the operation characteristics and the corresponding heat transfer mechanisms for different heat inputs (5 W up to 100 W) and different filling ratios (20% up to 95%) have been presented and elaborated. The results show that heat-transfer mechanism changed with the transition of operation patterns; before valid oscillation started, the thermal resistance was not like that described in the open literature where it decreased almost linearly, but would rather slowdown descending or even change into rise first before further decreasing (i.e. an inflection point existed); when the heat input further increased to certain level, e.g. 65 W or above, there presented a limit of heat-transfer performance which was independent of the types of working fluids and the filling ratios, but may be related to the structure, the material, the size and the inclination of the PHP. - Highlights: •The thermal mechanisms altered accordingly with the operation features in the PHP. •Unlike conventional heat pipes, continuous temperature soaring would not happen in the PHP. •Before the oscillation start-up, there existed a heat-transfer limit for the relatively stagnated flow in the PHP. •A limit of thermal performance existed in the PHP at relatively high heat inputs

  1. Combined action of S-carvone and mild heat treatment on Listeria monocytogenes Scott A

    NARCIS (Netherlands)

    Karatzas, A.K.; Bennik, M.H.J.; Smid, E.J.; Kets, E.P.W.

    2000-01-01

    The combined action of the plant-derived volatile, S-carvone, and mild heat treatment on the food-borne pathogen, Listeria monocytogenes, was evaluated. The viability of exponential phase cultures grown at 8 °C could be reduced by 1.3 log units after exposure to S-carvone (5 mmol 1-1) for 30 min at

  2. A new methodology for greenhouse gas reduction in industry through improved heat exchanging and/or integration of combined heat and power

    International Nuclear Information System (INIS)

    Axelsson, H.; Asblad, A.; Berntsson, T.

    1999-01-01

    This paper presents a method that identifies economically optimal combinations of enhanced heat recovery, integration of combined heat and power (CHP), and fuel switching, in an existing industrial energy system at various emission levels. Novel types of composite curves based on pinch technology, representing the existing temperature levels for supplying heat and the possible ones that may be attained after retrofitting, are used as tools for estimating the opportunities for CHP and the trade-off between improved heat exchanging and CHP. The method is explained by an example. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  3. Evaluating combined effect of noise and heat on blood pressure changes among males in climatic chamber

    OpenAIRE

    Dehghan, Habibollah; Bastami, Mohamad Taghi; Mahaki, Behzad

    2017-01-01

    INTRODUCTION: Exposure to noise and heat causes individuals to experience some changes in the function of cardiovascular system in workplaces. This study aimed to find the combined effect of heat and noise on systolic and diastolic types of blood pressure in experimentally controlled conditions. METHODS: This quasi-experimental study was performed with 12 male students in a climatic chamber in 2014. Blood pressure including systolic and diastolic was measured in the following conditions: 15 m...

  4. Heat treatment of transparent Yb:YAG and YAG ceramics and its influence on laser performance

    Science.gov (United States)

    Fujioka, Kana; Mochida, Tetsuo; Fujimoto, Yasushi; Tokita, Shigeki; Kawanaka, Junji; Maruyama, Momoko; Sugiyama, Akira; Miyanaga, Noriaki

    2018-05-01

    Composite transparent ceramic materials are promising for improving the performance of high-average-power lasers. A combination of room-temperature bonding via surface treatment by a fast atom beam and diffusion bonding via heating, which effectively controls the ion diffusion distance near the interface, makes the laser materials suitable for a variety of oscillator/amplifier. During the heat treatment of yttrium aluminum garnet (YAG) ceramics, the Si ions in the solid solution of the sintering aid incorporated within the grains were seen to segregate at the grain boundary, resulting in an increase of scattering sites. The number density and size of the scattering sites strongly depended on the post-heating temperature rather than the heating time. Specifically, heating at 1300 °C did not affect the transmittance of the YAG ceramic, whereas both the size and number of scattering sites substantially increased with a heat treatment at 1400 °C. The laser oscillation experiment using cryogenically-cooled Yb:YAG ceramics exhibited heating temperature dependence of the slope efficiency owing to the increasing scattering loss.

  5. Preliminary study concerning the influence of combined heat and radiation treatment on the quality of some horticultural products

    International Nuclear Information System (INIS)

    Langerak, D.Is.; Bruurs, M.F.J.

    1973-01-01

    In collaboration with a canning factory a number of horticultural products were preserved by means of the combined irradiation and heating treatment. The aim was to study the influence of the parameters irradiation and heat on quality and microbiological spoilage. The products were exposed to gamma-rays with doses varying from 0 to 1 Mrad. The heat treatment varied from 5 to 40 minutes at 98 to 121 0 C; time and temperature depended on the type of product. The sterilization value (F value) was measured by means of the method of Esty and Meyer for products with pH>5. The canned products were stored afterwards at 20-55 0 C. The organoleptic test showed that the colour and texture of most products were improved by the combined treatment, provided the irradiation dose did not exceed 0.25 Mrad. Strawberries in syrup discoloured at 0.1 Mrad. For a number of products the improved colour was partially lost during storage. Flavour and taste were not generally influenced unfavourably at doses up to 0.3 Mrad (exception: strawberries). The treatment sequence did not affect distinctly the quality or microbiological spoilage. The sterilization time (F value) of the combined treatment was determined by the shortest heating period required for the tenderness of the product. (F.J.)

  6. Configuring a fuel cell based residential combined heat and power system

    Science.gov (United States)

    Ahmed, Shabbir; Papadias, Dionissios D.; Ahluwalia, Rajesh K.

    2013-11-01

    The design and performance of a fuel cell based residential combined heat and power (CHP) system operating on natural gas has been analyzed. The natural gas is first converted to a hydrogen-rich reformate in a steam reformer based fuel processor, and the hydrogen is then electrochemically oxidized in a low temperature polymer electrolyte fuel cell to generate electric power. The heat generated in the fuel cell and the available heat in the exhaust gas is recovered to meet residential needs for hot water and space heating. Two fuel processor configurations have been studied. One of the configurations was explored to quantify the effects of design and operating parameters, which include pressure, temperature, and steam-to-carbon ratio in the fuel processor, and fuel utilization in the fuel cell. The second configuration applied the lessons from the study of the first configuration to increase the CHP efficiency. Results from the two configurations allow a quantitative comparison of the design alternatives. The analyses showed that these systems can operate at electrical efficiencies of ∼46% and combined heat and power efficiencies of ∼90%.

  7. ABA Is Required for Plant Acclimation to a Combination of Salt and Heat Stress.

    Directory of Open Access Journals (Sweden)

    Nobuhiro Suzuki

    Full Text Available Abiotic stresses such as drought, heat or salinity are a major cause of yield loss worldwide. Recent studies revealed that the acclimation of plants to a combination of different environmental stresses is unique and cannot be directly deduced from studying the response of plants to each of the different stresses applied individually. Here we report on the response of Arabidopsis thaliana to a combination of salt and heat stress using transcriptome analysis, physiological measurements and mutants deficient in abscisic acid, salicylic acid, jasmonic acid or ethylene signaling. Arabidopsis plants were found to be more susceptible to a combination of salt and heat stress compared to each of the different stresses applied individually. The stress combination resulted in a higher ratio of Na+/K+ in leaves and caused the enhanced expression of 699 transcripts unique to the stress combination. Interestingly, many of the transcripts that specifically accumulated in plants in response to the salt and heat stress combination were associated with the plant hormone abscisic acid. In accordance with this finding, mutants deficient in abscisic acid metabolism and signaling were found to be more susceptible to a combination of salt and heat stress than wild type plants. Our study highlights the important role abscisic acid plays in the acclimation of plants to a combination of two different abiotic stresses.

  8. Combined Heat and Power

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    At their 2007 Summit in Heiligendamm, G8 leaders called on countries to 'adopt instruments and measures to significantly increase the share of combined heat and power (CHP) in the generation of electricity.' As a result, energy, economic, environmental and utility regulators are looking for tools and information to understand the potential of CHP and to identify appropriate policies for their national circumstances. This report forms the first part of the response. It includes answers to policy makers' questions about the potential economic, energy and environmental benefits of an increased policy commitment to CHP. It also includes for the first time integrated IEA data on global CHP installations, and analyses the benefits of increased CHP investment in the G8+5 countries. A companion report will be produced later in 2008 to document best practice policy approaches that have been used to expand the use of CHP in a variety of countries.

  9. Numerical analyses of the effect of a biphasic thermosyphon vapor channel sizes on the heat transfer intensity when heat removing from a power transformer of combined heat and power station

    Directory of Open Access Journals (Sweden)

    Nurpeiis Atlant

    2017-01-01

    Full Text Available Numerical analyses of the effect of a biphasic thermosyphon vapor channel sizes on the heat transfer intensity was conducted when heat removing from an oil tank of a power transformer of combined heat and power station (CHP. The power transformer cooling system by the closed biphasic thermosyphon was proposed. The mathematical modeling of heat transfer and phase transitions of coolant in the thermosyphon was performed. The problem of heat transfer is formulated in dimensionless variables “velocity vorticity vector – current function – temperature” and solved by finite difference method. As a result of numerical simulation it is found that an increase in the vapor channel length from 0.15m to 1m leads to increasing the temperature difference by 3.5 K.

  10. Flue gas recovery system for natural gas combined heat and power plant with distributed peak-shaving heat pumps

    International Nuclear Information System (INIS)

    Zhao, Xiling; Fu, Lin; Wang, Xiaoyin; Sun, Tao; Wang, Jingyi; Zhang, Shigang

    2017-01-01

    Highlights: • A flue gas recovery system with distributed peak-shaving heat pumps is proposed. • The system can improve network transmission and distribution capacity. • The system is advantageous in energy saving, emission reduction and economic benefits. - Abstract: District heating systems use distributed heat pump peak-shaving technology to adjust heat in secondary networks of substations. This technology simultaneously adjusts the heat of the secondary network and reduces the return-water temperature of the primary network by using the heat pump principle. When optimized, low temperature return-water is able to recycle more waste heat, thereby further improving the heating efficiency of the system. This paper introduces a flue gas recovery system for a natural gas combined heat and power plant with distributed peak-shaving heat pumps. A pilot system comprising a set of two 9F gas-steam combined cycle-back pressure heating units was used to analyse the system configuration and key parameters. The proposed system improved the network transmission and distribution capacity, increased heating capacity, and reduced heating energy consumption without compromising heating safety issues. As such, the proposed system is advantageous in terms of energy saving, emission reduction, and economic benefits.

  11. District heating and combined heat and power generation from biomass

    International Nuclear Information System (INIS)

    Veski, Rein

    1999-01-01

    An Altener programme seminar District Heating and Combined Heat and Power Generation from Biomass. Minitraining seminar and study tours and also Business forum, Exhibition and Short company presentations were held in Tallinn on March 21-23, 1999. The Seminar was organised by the VTT Energy, the Estonian Bioenergy Association and the Estonian Heat and Power Association in co-operation with the AFB-net. The Agricultural and Forestry Biomass Network (AFB-net) is part of the ALTENER programme. The Network aims at promoting and stimulating the implementation and commercial utilisation of energy from biomass and waste, through the initiation of business opportunities. This includes national and international co-operation and the exchange of the personnel. The Seminar was attended by consulting companies, scientists, municipal authorities and representatives of co-ordinating bodies engaged in renewable energy management as well as DH and CHP plant managers, equipment manufacturers and local energy planners from Finland, Estonia, Latvia, Lithuania, Sweden, Denmark, Belgium, Slovenia and Slovak Republic. At the Seminar minitraining issues were dealt with: the current situation and future trends in biomass DH in the Baltic Sea countries, and biomass DH and CHP in Eastern and Central Europe, planning and construction of biomass-based DH plants, biomass fuel procurement and handling technology, combustion technology, DH networks, financing of biomass projects and evaluating of projects, and case projects in Eastern and Central European countries. The following were presented: boilers with a capacity of 100 kW or more, stoker burners, wood and straw handling equipment, wood fuel harvesters, choppers, pelletisers, district heating pipelines and networks. (author)

  12. Exergy, Economic and Environmental Analysis for Simple and Combined Heat and Power IC Engines

    Directory of Open Access Journals (Sweden)

    Mehdi Aliehyaei

    2015-04-01

    Full Text Available This study reports the results of exergy, economic and environmental analyses of simple and combined heat and power internal combustion engines. Values of entropy production, second law efficiency are calculated, and an objective function, including initial, operation, maintenance and fuel costs, as well as the external costs of environmental pollutants, such as CO2, CO and NOx, are presented for the flue gas of the internal combustion engine. The results show that entropy generation in the combined heat and power mode is 30% lower than that in the simple internal combustion engine. Also, by excessively increasing the air ratio, the system entropy generation decreases in both cases of simple and combined heat and power IC engines. The greatest portion of entropy generation is related to the combined heat and power internal combustion engine. The gas heat exchanger generates more entropy than the jacket heat exchanger. Lower values of electricity cost and external costs of air pollution are provided by higher values of molar air to fuel ratio. The environmental aspects depend on location of the system and time of engine operation.

  13. Combined heat and power system with advanced gasification technology for biomass wastes

    Energy Technology Data Exchange (ETDEWEB)

    Mochida, S.; Abe, T.; Yasuda, T. [Nippon Furnace Kogyo Kaisha Ltd, Yokohama (Japan); Gupta, A.K. [Maryland Univ., College Park, MD (United States). Dept. of Mechnical Engineering

    2013-07-01

    The results obtained from an advanced gasification system utilizing high temperature steam are presented here. The results showed successful demonstration of clean syngas production having high calorific value fuel ({proportional_to}10 MJ/m{sup 3}N) using woody biomass wastes in a downdraft type gasifier. The gasification capacity of the plant on dry basis was 60 kg/h. The syngas produced can be utilized in an absorption type chiller for air conditioning. This advanced gasification technology allows one to transform wastes to clean energy at local production sites without any environmental impact and expensive waste transportation costs. The experience gained from the demonstration plant allows one to implement to other industrial applications for use as a decentralized unit and obtain clean syngas for local use. The demonstration conducted here shows that the system is favorable for onsite use of compatible combined heat and power (CHP) system including light oil supported diesel engine power generator. The biomass waste fuel from a lumber mill factory was used in this study. The factory handles a wide forests area of about 50 ha and produces about 2,500 m{sup 3}/year of wood chips from thin out trees and waste lumbers. This translates to a maximum 110 kg/h of wood chips that can be fed to a gasifier. The syngas produced was used for the combined heat and power system. Local use of biomass for fuel reforming reduces the cost of collection and transportation costs so that a sustainable business is demonstrated with profit from the generated electricity and thermal energy. The cost structure incorporates both the depreciation cost and operation cost of the system. Thermal energy from hot water can be used for drying lumbers and wood chips in a cascade manner. The drying process can be adopted for enhancing its productivity with increased variability on the quality of lumber. The results show that the combined heat and power system (CHP) offers good profitable

  14. Thermodynamic evaluation of CHP (combined heat and power) plants integrated with installations of coal gasification

    International Nuclear Information System (INIS)

    Ziębik, Andrzej; Malik, Tomasz; Liszka, Marcin

    2015-01-01

    Integration of a CHP steam plant with an installation of coal gasification and gas turbine leads to an IGCC-CHP (integrated gasification combined cycle-combined heat and power). Two installations of coal gasification have been analyzed, i.e. pressurized entrained flow gasifier – case 1 and pressurized fluidized bed gasifier with CO_2 recirculation – case 2. Basing on the results of mathematical modelling of an IGCC-CHP plant, the algorithms of calculating typical energy indices have been derived. The following energy indices are considered, i.e. coefficient of heat performance and relative savings of chemical energy of fuels. The results of coefficients of heat performance are contained between 1.87 and 2.37. Values exceeding 1 are thermodynamically justified because the idea of cogeneration of heat and electricity based on combining cycles of the heat engine and heat pump the efficiency of which exceeds 1. Higher values concerning waste heat replace more thermodynamically effective sources of heat in CHP plants. Relative savings of the chemical energy of fuels are similar in both cases of IGCC-CHP plants and are contained between the lower value of the CHP (combined heat and power) plants fuelled with coal and higher value of CHP plants fired with natural gas. - Highlights: • Energy savings of fuel is an adequate measure of cogeneration. • Relative energy savings of IGCC-CHP is near the result of a gas and steam CHP. • COHP (coefficient of heat performance) can help to divide fuel between heat fluxes. • Higher values of COHP in the case of waste heat recovery result from the lower thermal parameters.

  15. Subjective evaluation of different ventilation concepts combined with radiant heating and cooling

    DEFF Research Database (Denmark)

    Krajcik, Michal; Tomasi, Roberta; Simone, Angela

    2012-01-01

    Sixteen subjects evaluated the indoor environment in four experiments with different combinations of ventilation and radiant heating/cooling systems. Two test setups simulated a room in a low energy building with a single occupant during winter. The room was equipped either by a ventilation system...... supplying warm air space heating or by a combination of radiant floor heating and mixing ventilation system. Next two test setups simulated an office room with two occupants during summer, ventilated and cooled by a single displacement ventilation system or by a radiant floor cooling combined...

  16. Effects of combined heat and ionizing radiation on thiamine (Vitamin B1) content in model systems and food matrices

    International Nuclear Information System (INIS)

    Chuaqui-Offermanns, N.; Shoemaker, L.; McDougall, T.

    1989-01-01

    The effects of heat and radiation on thiamine stability are being studied both singly and in combination. Heat, γ-radiation and a combination of them were applied to a model system consisting of 2 x 10 -5 M thiamine hydrochloride in 0.01N HCl (pH=2.5), and their effects are reported. The effects of these two agents on thiamine in two food matrices, concentrated orange juice and green peas, are also reported. Heat was not found to have a significant effect on thiamine in the model system at temperatures up to 120 0 C for up to 60 min of treatment. A small, but significant heat effect was found in the two foods. The retention of thiamine in the model system and in the two foods decreased exponentially as the radiation dose increased. The degradation of thiamine by γ-radiation in both foods was a factor of 10 less than that observed in the model system. A small, but significant synergistic effect was found when samples of the model system were heated at 120 0 C for one hour 24 h after irradiation. (author)

  17. Application of industrial wood residues for combined heat and power production

    International Nuclear Information System (INIS)

    Majchrzycka, A.

    2015-01-01

    The paper discusses combined production of heat and power (CHP) from industrial wood residues. The system will be powered by wood residues generated during manufacturing process of wooden floor panels. Based on power and heat demands of the plant and wood residues potential, the CHP system was selected. Preliminary analysis of biomass conversion in CHP system and environmental impact was performed.

  18. Combined Heat and Power and Emissions Trading

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    The aim of this IEA Information Paper is to help policy makers and other stakeholders understand the challenges facing the incorporation of high efficiency combined heat and power (CHP) into greenhouse gas (GHG) Emissions Trading Schemes (ETSs) -- and to propose options for overcoming them.

  19. Micro-Combined Heat and Power Device Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NIST has developed a test facility for micro-combined heat and power (micro-CHP) devices to measure their performance over a range of different operating strategies...

  20. A Benders decomposition approach for a combined heat and power economic dispatch

    International Nuclear Information System (INIS)

    Abdolmohammadi, Hamid Reza; Kazemi, Ahad

    2013-01-01

    Highlights: • Benders decomposition algorithm to solve combined heat and power economic dispatch. • Decomposing the CHPED problem into master problem and subproblem. • Considering non-convex heat-power feasible region efficiently. • Solving 4 units and 5 units system with 2 and 3 co-generation units, respectively. • Obtaining better or as well results in terms of objective values. - Abstract: Recently, cogeneration units have played an increasingly important role in the utility industry. Therefore the optimal utilization of multiple combined heat and power (CHP) systems is an important optimization task in power system operation. Unlike power economic dispatch, which has a single equality constraint, two equality constraints must be met in combined heat and power economic dispatch (CHPED) problem. Moreover, in the cogeneration units, the power capacity limits are functions of the unit heat productions and the heat capacity limits are functions of the unit power generations. Thus, CHPED is a complicated optimization problem. In this paper, an algorithm based on Benders decomposition (BD) is proposed to solve the economic dispatch (ED) problem for cogeneration systems. In the proposed method, combined heat and power economic dispatch problem is decomposed into a master problem and subproblem. The subproblem generates the Benders cuts and master problem uses them as a new inequality constraint which is added to the previous constraints. The iterative process will continue until upper and lower bounds of the objective function optimal values are close enough and a converged optimal solution is found. Benders decomposition based approach is able to provide a good framework to consider the non-convex feasible operation regions of cogeneration units efficiently. In this paper, a four-unit system with two cogeneration units and a five-unit system with three cogeneration units are analyzed to exhibit the effectiveness of the proposed approach. In all cases, the

  1. A contribution to the sessile oak site and beech site defining in central Serbia

    Directory of Open Access Journals (Sweden)

    Krstić Milun

    2009-01-01

    Full Text Available The study was carried out in sessile oak forests and beech forests in the region central Serbia. The stands are classified as pure stands with the percentage of other species up to 10% per tree number, mixed forests of sessile oak with other species, and mixed forests of beech with other species, whose percentage does not exceed 50%. Altogether 257 stands were monitored - 202 beech stands and 55 sessile oak stands. By the applied method of defining the local heat potential (Lujić, 1960, modified by Ratknić et al. (2001 and Krstić (2004, 2008, which represents possibility of soil heating without vegetation, were determined. In this way, a scale of 162 possible combinations of local heat potential was obtained, which explains more precisely the dependence of beech stands and sessile oak stands on the topographic conditions. By applying the weighted values of the thermal co-ordinates of aspect and slope (E for each altitudinal belt of 100 m, it was concluded that pure stands have the widest ecological range. Pure beech stands occur at the sites with 34 combinations of thermal co-ordinates E.V=4.6 to 8.12. Pure sessile oak stands occur at the sites with 12 combinations of thermal co-ordinates E.V=5.10 to 8.11. The percentage of mixed beech stands with other broadleaf species is the highest at the sites with the co-ordinate V=10-11 (at the altitudes between 700 and 900 m is about 60 %. Mixed stands of sessile oak and beech are located on the terrains with combinations of thermal co-ordinates E.V=7.9 to 8.12. By using the local heat potential of a region, it can be identified which sites, i.e. which combinations of exposure, slope and altitude belong to the particular tree species. Consequently, a more reliable selection of tree species can be done for the bio-reclamation of barrens and other deforested terrains.

  2. Combined treatments of heat, irradiation, and pH effects on infectivity of foot-and-mouth disease virus in bovine tissues

    International Nuclear Information System (INIS)

    Lasta, J.; Blackwell, J.H.; Sadir, A.; Gallinger, M.; Marcoveccio, F.; Zamorano, M.; Ludden, B.; Rodriguez, R.

    1992-01-01

    Various traditional methods for processing meat products were examined for their virucidal effects on the A, O, and C serotypes of foot-and-mouth disease virus. Aging, curing, heating at 78 degrees C for 20 min or irradiation (1.5 Mrad, 2.4 Mrad) that did not alter the sensory characteristics of the product were used singly or in combination. The only processing treatment that was virucidal was the combination of heat and gamma irradiation

  3. Micro combined heat and power operating on renewable energy for residential building

    International Nuclear Information System (INIS)

    Aoun, Bernard

    2008-01-01

    The building sector consumes more than 43% of the total national energy consumption in France leading to more than 25% of CO 2 emissions associated to this energy consumption. A large number of options exist to limit CO 2 emissions and to improve the performance of buildings. One of these options is developed in this thesis, the use of renewable energies (solar and biomass) in combined production of heat and power. Conventional systems of combined heat and power production are briefly analyzed. The major part of this work has been focused on the development of a micro-CHP system based on an organic Rankine cycle operating on renewable energies intermittent and non-intermittent (solar and wood). The working fluids have been analyzed to allow reaching high thermodynamic performance. The different promising technologies, for each components of the system are identified, depending on the working fluid. A special test bench has been designed and realized to test and characterize an oil-free vapor scroll expander suitable for our application. The different components have been sized using computerized tools developed for the modeling of the Organic Rankine cycle. A dynamic simulation tool has been developed to simulate the annual performance of the micro-CHP system operating under different climate conditions and thermal loads. Results show that the micro-CHP system could save more than 40% of the primary energy consumption and up to 60% of CO 2 emissions. The Levelized electricity cost has been calculated using economic analysis; results show that the electricity cost (50 c-euros/kWhel) is still high compared to other technologies. (author)

  4. Heat flow at the Platanares, Honduras, geothermal site

    Science.gov (United States)

    Meert, Joseph G.; Smith, Douglas L.

    1991-03-01

    Three boreholes, PLTG-1, PLTG-2 and PLTG-3, were drilled in the Platanares, Honduras geothermal system to evaluate the geothermal energy potential of the site. The maximum reservoir temperature was previously estimated at 225-240°C using various types of chemical and isotopic geothermometry. Geothermal gradients of 139-239°C/km, calculated from two segments of the temperature-depth profile for borehole PLTG-2, were used to project a minimum depth to the geothermal reservoir of 1.2-1.7 km. Borehole PLTG-1 exhibited an erratic temperature distribution attributed to fluid movement through a series of isolated horizontal and subhorizontal fractures. The maximum measured temperature in borehole PLTG-1 was 150.4°C, and in PLTG-2 the maximum measured temperature was 104.3°C. PLTG-3 was drilled after this study and the maximum recorded temperature of 165°C is similar to the temperature encountered in PLTG-1. Heat flow values of 392 mWm -2 and 266 mWm -2 represent the first directly-measured heat flow values for Honduras and northen Central America. Radioactive heat generation, based on gamma-ray analyses of uranium, thorium and potassium in five core samples, is less than 2.0 μWm -3 and does not appear to be a major source of the high heat flow. Several authors have proposed a variety of extensional tectonic environments for western Honduras and these heat flow values, along with published estimates of heat flow, are supportive of this type of tectonic regime.

  5. Heat transfer enhancement on nucleate boiling

    International Nuclear Information System (INIS)

    Zhuang, M.; Guibai, L.

    1990-01-01

    This paper reports on enhancement of nucleate boiling heat transfer with additives that was investigated experimentally. More than fifteen kinds of additives were chosen and tested. Eight kinds of effective additives which can enhance nucleate boiling heat transfer were selected. Experimental results showed that boiling heat transfer coefficient of water was increased by 1 to 5 times and that of R-113 was increased by 1 to 4 times when trace amount additives were put in the two boiling liquids. There exist optimum concentrations for the additives, respectively, which can enhance nucleate boiling heat transfer rate best. In order to analyze the mechanism of the enhancement of boiling heat transfer with additives, the surface tension and the bubble departure diameter were measured. The nucleation sites were investigated by use of high-speed photograph. Experimental results showed that nucleation sites increase with additive amount increasing and get maximum. Increasing nucleation sites is one of the most important reason why nucleate boiling heat transfer can be enhanced with additives

  6. Energy and environmental evaluation of combined cooling heating and power system

    Science.gov (United States)

    Bugaj, Andrzej

    2017-11-01

    The paper addresses issues involving problems of implementing combined cooling, heating and power (CCHP) system to industrial facility with well-defined demand profiles of cooling, heating and electricity. The application of CCHP system in this particular industrial facility is being evaluated by comparison with the reference system that consists of three conventional methods of energy supply: (a) electricity from external grid, (b) heat from gas-fired boilers and (c) cooling from vapour compression chillers run by electricity from the grid. The CCHP system scenario is based on the combined heat and power (CHP) plant with gas turbine-compressor arrangement and water/lithium bromide absorption chiller of a single-effect type. Those two scenarios are analysed in terms of annual primary energy usage as well as emissions of CO2. The results of the analysis show an extent of primary energy savings of the CCHP system in comparison with the reference system. Furthermore, the environmental impact of the CCHP usage, in the form of greenhouse gases emission reductions, compares quite favourably with the reference conventional option.

  7. Technical Analysis of Combined Solar Water Heating Systems for Cold Climate Regions

    OpenAIRE

    Hossein Lotfizadeh; André McDonald; Amit Kumar

    2016-01-01

    Renewable energy resources, which can supplement space and water heating for residential buildings, can have a noticeable impact on natural gas consumption and air pollution. This study considers a technical analysis of a combined solar water heating system with evacuated tube solar collectors for different solar coverage, ranging from 20% to 100% of the total roof area of a typical residential building located in Edmonton, Alberta, Canada. The alternative heating systems were conventional (n...

  8. 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.

    2015-04-01

    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.

  9. Study on subcooled-forced flow boiling heat transfer and critical heat flux of solid particle-water two-phase mixture

    International Nuclear Information System (INIS)

    Koizumi, Yasuo; Mochizuki, Manabu; Ohtake, Hiroyasu

    1999-01-01

    The effect of solid particle introduction on forced flow boiling and the critical heat flux was examined for the mixture of subcooled-water and 0.6 mm glass beads. When the particles were introduced, the growth on of a superheated layer near a wall seemed to be suppressed and the onset of nucleate boiling was delayed. The particles tempted for bubbles to condense at nucleation sites, and then the initiation of net vapor generation was also delayed and sifted to a high wall-superheat region. The nucleate boiling heat transfer was augmented by the particles, which considered to be caused by the combination of the suppression of the superheated layer growth and the promotion of the condensation and dissipation of the bubbles. The wall superheat at the critical heat flux condition was sifted to a high wall superheat region and the critical heat flux itself was also elevated a little. (author)

  10. Investigation of a heat storage for a solar heating system for combined space heating and domestic hot water supply for homeowner´s association "Bakken"

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1998-01-01

    A heat storage for a solar heating system for combined space heating and domestic hot water supply was tested in a laboratory test facility.The heat storage consist of a mantle tank with water for the heating system and of a hot water tank, which by means of thermosyphoning is heated by the water...

  11. Retrofitting Combined Space and Water Heating Systems: Laboratory Tests

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbauer, B.; Bohac, D.; Huelman, P.; Olson, R.; Hewitt, M.

    2012-10-01

    Better insulated and tighter homes can often use a single heating plant for both space and domestic water heating. These systems, called dual integrated appliances (DIA) or combination systems, can operate at high efficiency and eliminate combustion safety issues associated by using a condensing, sealed combustion heating plant. Funds were received to install 400 DIAs in Minnesota low-income homes. The NorthernSTAR DIA laboratory was created to identify proper system components, designs, operating parameters, and installation procedures to assure high efficiency of field installed systems. Tests verified that heating loads up to 57,000 Btu/hr can be achieved with acceptable return water temperatures and supply air temperatures.

  12. Retrofitting Combined Space and Water Heating Systems. Laboratory Tests

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbauer, B. [NorthernStar Building America Partnership, St. Paul, MN (United States); Bohac, D. [NorthernStar Building America Partnership, St. Paul, MN (United States); Huelman, P. [NorthernStar Building America Partnership, St. Paul, MN (United States); Olsen, R. [NorthernStar Building America Partnership, St. Paul, MN (United States); Hewett, M. [NorthernStar Building America Partnership, St. Paul, MN (United States)

    2012-10-01

    Better insulated and tighter homes can often use a single heating plant for both space and domestic water heating. These systems, called dual integrated appliances (DIA) or combination systems, can operate at high efficiency and eliminate combustion safety issues associated by using a condensing, sealed combustion heating plant. Funds were received to install 400 DIAs in Minnesota low-income homes. The NorthernSTAR DIA laboratory was created to identify proper system components, designs, operating parameters, and installation procedures to assure high efficiency of field installed systems. Tests verified that heating loads up to 57,000 Btu/hr can be achieved with acceptable return water temperatures and supply air temperatures.

  13. ASSESSMENT OF COMBINED HEAT AND POWER SYSTEM"PREMIUM POWER" APPLICATIONS IN CALIFORNIA

    Energy Technology Data Exchange (ETDEWEB)

    Norwood, Zack; Lipman, Timothy; Stadler, Michael; Marnay, Chris

    2010-06-01

    The effectiveness of combined heat and power (CHP) systems for power interruption intolerant,"premium power," facilities is the focus of this study. Through three real-world case studies and economic cost minimization modeling, the economic and environmental performance of"premium power" CHP is analyzed. The results of the analysis for a brewery, data center, and hospital lead to some interesting conclusions about CHP limited to the specific CHP technologies installed at those sites. Firstly, facilities with high heating loads prove to be the most appropriate for CHP installations from a purely economic standpoint. Secondly, waste heat driven thermal cooling systems are only economically attractive if the technology for these chillers can increase above the current best system efficiency. Thirdly, if the reliability of CHP systems proves to be as high as diesel generators they could replace these generators at little or no additional cost if the thermal to electric (relative) load of those facilities was already high enough to economically justify a CHP system. Lastly, in terms of greenhouse gas emissions, the modeled CHP systems provide some degree of decreased emissions, estimated at approximately 10percent for the hospital, the application with the highest relative thermal load in this case

  14. A mixed integer linear programming model for integrating thermodynamic cycles for waste heat exploitation in process sites

    International Nuclear Information System (INIS)

    Oluleye, Gbemi; Smith, Robin

    2016-01-01

    Highlights: • MILP model developed for integration of waste heat recovery technologies in process sites. • Five thermodynamic cycles considered for exploitation of industrial waste heat. • Temperature and quantity of multiple waste heat sources considered. • Interactions with the site utility system considered. • Industrial case study presented to illustrate application of the proposed methodology. - Abstract: Thermodynamic cycles such as organic Rankine cycles, absorption chillers, absorption heat pumps, absorption heat transformers, and mechanical heat pumps are able to utilize wasted thermal energy in process sites for the generation of electrical power, chilling and heat at a higher temperature. In this work, a novel systematic framework is presented for optimal integration of these technologies in process sites. The framework is also used to assess the best design approach for integrating waste heat recovery technologies in process sites, i.e. stand-alone integration or a systems-oriented integration. The developed framework allows for: (1) selection of one or more waste heat sources (taking into account the temperatures and thermal energy content), (2) selection of one or more technology options and working fluids, (3) selection of end-uses of recovered energy, (4) exploitation of interactions with the existing site utility system and (5) the potential for heat recovery via heat exchange is also explored. The methodology is applied to an industrial case study. Results indicate a systems-oriented design approach reduces waste heat by 24%; fuel consumption by 54% and CO_2 emissions by 53% with a 2 year payback, and stand-alone design approach reduces waste heat by 12%; fuel consumption by 29% and CO_2 emissions by 20.5% with a 4 year payback. Therefore, benefits from waste heat utilization increase when interactions between the existing site utility system and the waste heat recovery technologies are explored simultaneously. The case study also shows

  15. A combined heating cooling stage for cluster thermalization in the gas phase

    International Nuclear Information System (INIS)

    Ievlev, D.N.; Kuester, A.; Enders, A.; Malinowski, N.; Schaber, H.; Kern, K.

    2003-01-01

    We report on the design and performance of a combined heating/cooling stage for the thermalization of clusters in a gas phase time-of-flight mass spectrometer. With this setup the cluster temperature can sensitively be adjusted within the range from 100 up to 800 K and higher. The unique combination of a heating stage with a subsequent cooling stage allows us to perform thermodynamic investigations on clusters at very high temperatures without quality losses in the spectra due to delayed fragmentation in the drift tube of the mass spectrometer. The performance of the setup is demonstrated by the example of (C 60 ) n clusters

  16. Application of biogas for combined heat and power production in the rural region

    International Nuclear Information System (INIS)

    Kozak, T.; Majchrzycka, A.

    2009-01-01

    The paper discusses combined production of heat and power (CHP) from biogas in a small-scale power plant placed in the rural region. Based on power and heat demands of the rural region and biomass supply, the CHP system was selected. Keywords: biogas, cogeneration

  17. Heat pumps combined with cold storage; Warmtepompen gecombineerd met koudeopslag

    Energy Technology Data Exchange (ETDEWEB)

    Van Ingen, M.A. [Techniplan Adviseurs, Rotterdam (Netherlands)

    1999-09-01

    The architects of the new Nike head office building in Hilversum, Netherlands, opted for a heat pump combined with a cold storage system. The most efficient design was found to be a single central location for the production of heat and cold, with distribution lines to each of the five buildings. The cold storage system provides direct cooling and indirect heating: the heat pump raises the low-temperature heat from the cold storage to a usable temperature (augmented by district heating when necessary). In addition, the heat pump generates cold as a by-product in winter, which can be stored in the sources system and utilised during the following summer. The heat pump can also be used for cooling, for peak load supply and for any short-term storage requirement in emergencies

  18. Measure Guideline: Combined Space and Water Heating Installation and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbauer, B. [NorthernSTAR Building America Partnership, St. Paul, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, St. Paul, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, St. Paul, MN (United States)

    2017-03-01

    Combined space and water heater (combi or combo) systems are defined by their dual functionality. Combi systems provide both space heating and water heating capabilities with a single heat source. This guideline will focus on the installation and operation of residential systems with forced air heating and domestic hot water (DHW) functionality. Past NorthernSTAR research has used a combi system to replace a natural gas forced air distribution system furnace and tank type water heater (Schoenbauer et al. 2012; Schoenbauer, Bohac, and McAlpine 2014). The combi systems consisted of a water heater or boiler heating plant teamed with a hydronic air handler that included an air handler, water coil, and water pump to circulate water between the heating plant and coil. The combi water heater or boiler had a separate circuit for DHW. Past projects focused on laboratory testing, field characterization, and control optimization of combi systems. Laboratory testing was done to fully characterize and test combi system components; field testing was completed to characterize the installed performance of combi systems; and control methodologies were analyzed to understand the potential of controls to simplify installation and design and to improve system efficiency and occupant comfort. This past work was relied upon on to create this measure guideline.

  19. Measure Guideline: Combined Space and Water Heating Installation and Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbauer, B. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Bohac, D. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

    2017-03-03

    Combined space and water heater (combi or combo) systems are defined by their dual functionality. Combi systems provide both space heating and water heating capabilities with a single heat source. This guideline will focus on the installation and operation of residential systems with forced air heating and domestic hot water (DHW) functionality. Past NorthernSTAR research has used a combi system to replace a natural gas forced air distribution system furnace and tank type water heater (Schoenbauer et al. 2012; Schoenbauer, Bohac, and McAlpine 2014). The combi systems consisted of a water heater or boiler heating plant teamed with a hydronic air handler that included an air handler, water coil, and water pump to circulate water between the heating plant and coil. The combi water heater or boiler had a separate circuit for DHW. Past projects focused on laboratory testing, field characterization, and control optimization of combi systems. Laboratory testing was done to fully characterize and test combi system components; field testing was completed to characterize the installed performance of combi systems; and control methodologies were analyzed to understand the potential of controls to simplify installation and design and to improve system efficiency and occupant comfort. This past work was relied upon on to create this measure guideline.

  20. Combined Effect of Heating Rate and Microalloying Elements on Recrystallization During Annealing of Dual-Phase Steels

    Science.gov (United States)

    Bellavoine, Marion; Dumont, Myriam; Drillet, Josée; Hébert, Véronique; Maugis, Philippe

    2018-05-01

    Adjusting ferrite recrystallization kinetics during annealing is a way to control the final microstructure and thus the mechanical properties of advanced cold-rolled high-strength steels. Two strategies are commonly used for this purpose: adjusting heating rates and/or adding microalloying elements. The present work investigates the effect of heating rate and microalloying elements Ti, Nb, and Mo on recrystallization kinetics during annealing in various cold-rolled Dual-Phase steel grades. The use of combined experimental and modeling approaches allows a deeper understanding of the separate influence of heating rate and the addition of microalloying elements. The comparative effect of Ti, Nb, and Mo as solute elements and as precipitates on ferrite recrystallization is also clarified. It is shown that solute drag has the largest delaying effect on recrystallization in the present case and that the order of solute drag effectiveness of microalloying elements is Nb > Mo > Ti.

  1. Convective boiling in a parallel microchannel heat sink with a diverging cross-section design and artificial nucleation sites

    International Nuclear Information System (INIS)

    Lu, Chun Ting; Pan, Chin

    2009-01-01

    To develop a highly stable boiling heat transfer microchannel heat sink, the three types of diverging microchannels, namely Type-1, Type-2 and Type-3, were designed to explore experimentally the effect of different distribution of artificial nucleation sites on enhancing boiling heat transfer in 10 parallel diverging microchannels with a mean hydraulic diameter of 120 μm. The Type-1 system is with no cavities, Type-2 is with cavities distributed uniformly along the downstream half of the channel, while Type-3 is with cavities distributed uniformly along the whole channel. The artificial nucleation sites are laser-etched pits on the channel bottom wall with a mouth diameter of about 20-22 μm based on the heterogeneous nucleation theory. The results of the present study reveal the presence of the artificial nucleation sites for flow boiling in parallel diverging microchannel significantly reduces the wall superheat and enhances the boiling heat transfer performance. Additionally, the Type-3 design demonstrates the best boiling heat transfer performance. (author)

  2. Review of European regulatory and tariff experience with the sale of heat and electricity from combined heat and power plants

    International Nuclear Information System (INIS)

    Dyrelund, A.

    1991-12-01

    The Prince Edward Island Energy Corporation, Edmonton Power, Energy, Mines and Resources Canada and the Canadian Electrical Association commissioned a study to understand how electrical power and district heat from combined heat and power (CHP) plants is priced in Europe. Four northern European countries were investigated, Denmark, Germany, Sweden and Finland. These countries produce 45.8 TWh of power from combined heat and power plants, 7.1% of their annual consumption. In the case of Denmark, CHP accounts for 37.5% of its total power production. The energy situation in each country is reviewed using published statistics, and in particular the rapidly changing situation with regard to environmental and fuel taxes is examined. In order to obtain practical insights with regard to tariffs used by the various utilities, a series of generic examples were examined, supported by specific case studies. Technologies reviewed included: CHP from coal-fuelled extraction plant, CHP from coal-fuelled back pressure plant, waste heat from a municipal waste plant, and gas turbine with waste heat recovery. The benefits and risks associated with different tariff designs are discussed in detail including tariff formulae. This should enable interested parties to develop appropriate tariffs for combined heat and power plants in the context of current electrical utility policies. As a complement to the tariffs for combined heat and power plants, the design of district heating tariffs is also addressed. The typical concepts used in different countries are presented and discussed. 23 tabs

  3. Effects of combined heat and ionizing radiation on thiamine (Vitamin B sub 1 ) content in model systems and food matrices

    Energy Technology Data Exchange (ETDEWEB)

    Chuaqui-Offermanns, N.; Shoemaker, L.; McDougall, T. (Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Nuclear Research Establishment)

    1989-01-01

    The effects of heat and radiation on thiamine stability are being studied both singly and in combination. Heat, {gamma}-radiation and a combination of them were applied to a model system consisting of 2 x 10{sup -5}M thiamine hydrochloride in 0.01N HCl (pH=2.5), and their effects are reported. The effects of these two agents on thiamine in two food matrices, concentrated orange juice and green peas, are also reported. Heat was not found to have a significant effect on thiamine in the model system at temperatures up to 120{sup 0}C for up to 60 min of treatment. A small, but significant heat effect was found in the two foods. The retention of thiamine in the model system and in the two foods decreased exponentially as the radiation dose increased. The degradation of thiamine by {gamma}-radiation in both foods was a factor of 10 less than that observed in the model system. A small, but significant synergistic effect was found when samples of the model system were heated at 120{sup 0}C for one hour 24 h after irradiation. (author).

  4. The Characteristic of Molten Heat Salt Storage System Utilizing Solar Energy Combined with Valley Electric

    Directory of Open Access Journals (Sweden)

    LI .Jiu-ru

    2017-02-01

    Full Text Available With the environmental pollution and energy consumption clue to the large difference between peak and valley of power grid,the molten salt heat storage system(MSHSS utilizing solar Energy combined with valley electric is presented for good energy saving and low emissions. The costs of MSHSS utilizing solar Energy combined with valley electric are greatly reduced. The law of heat transfer in molten salt heat storage technology is studied with the method of grey correlation analysis. The results show the effect of elbow sizes on surface convective heat transfer coefficient with different flow velocities.

  5. Environomic multi-objective optimisation of a district heating network considering centralized and decentralized heat pumps

    International Nuclear Information System (INIS)

    Molyneaux, A.; Leyland, G.; Favrat, D.

    2010-01-01

    Concern for the environment has been steadily growing in recent years, and it is becoming more common to include environmental impact and pollution costs in the design problem along with construction, investment and operating costs. To economically respond to the global environmental problems ahead, progress must be made both on more sustainable technologies and on the design methodology, which needs to adopt a more holistic approach. Heat pumps and, in particular systems integrating heat pumps and cogeneration units, offer a significant potential for greenhouse gas reduction. This paper illustrates the application of a multi-objective and multi-modal evolutionary algorithm to facilitate the design and planning of a district heating network based on a combination of centralized and decentralized heat pumps combined with on-site cogeneration. Comparisons are made with an earlier study based on a single objective environomic optimisation of the same overall model.

  6. Optimization of Serial Combined System of Ground-Coupled Heat Pump and Solar Collector

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jun; CHEN Yan; LU Suzhen; CUI Junkui

    2009-01-01

    A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results,in which the solar collector was combined serially with a ground-coupled heat pump(GCHP).The universal optimal equations were solved by the constrained variable metric method considering both the performance and economics.Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating.The results indicated a system coefficient of performance(COP)of 3.9 for the optimal method under the seriaI heating mode,and 3.2 for the conventional one.In addition,the optimum solution also showed advantages in energy and cost saving.1eading to a 16.7%improvement in the heat pump performance at 17.2%less energy consumption and 11.8%lower annual cost,respectively.

  7. Upscaling a district heating system based on biogas cogeneration and heat pumps

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; Fink, J.; Smit, Gerardus Johannes Maria; de Wit, Jan B.

    2015-01-01

    The energy supply of the Meppel district Nieuwveense landen is based on biogas cogeneration, district heating, and ground source heat pumps. A centrally located combined heat and power engine (CHP) converts biogas from the municipal wastewater treatment facility into electricity for heat pumps and

  8. Testing for cross-subsidisation in the combined heat and power generation sector

    DEFF Research Database (Denmark)

    Amundsen, Eirik S; Andersen, Per; Jensen, Frank

    2011-01-01

    In this paper we examine cross-subsidisation among combined heat and power producers in Denmark.Information on stand-alone costs for heat generation allows us to empirically compare the Faulhaber tests,tests with an upper bound on stand-alone costs (the Palmer tests) and the fully distributed cos...... test (FDC). All tests indicate a substantial amount of cross-subsidisation from heat generation to power generation. It is shown that the FDC test is closer to that of the Faulhaber tests in its results than the Palmer tests. Thus as the Faulhaber tests are considered in the literature...

  9. Siting analysis and risk assessment for small single-purpose heating reactors

    International Nuclear Information System (INIS)

    Tarjanne, R.

    1979-04-01

    Two alternative sites both 10km away from the centre of Helsinki are considered for reactor unit sizes of 400mw and 800mw. The risks associated with a small single-purpose heating reactor is evaluated for normal operation and accident conditions. The evaluation for accident condition is performed for three characteristics accidents. Three pathways are considered in the calculation of the radiation exposure: direct external gamma dose from the release plume, direct gamma radiation from deposited activity on the ground and dose due to inhalation. The risks are compared with the risks from alternative conventional fossil fuelled district heat production methods. The results show that the heating reactor alternative causes an unsignificant risk, which is far less than the risk caused by the fossil-fuelled alternatives

  10. Effect of reflecting modes on combined heat transfer within an anisotropic scattering slab

    International Nuclear Information System (INIS)

    Yi Hongliang; Tan Heping; Lu Yiping

    2005-01-01

    Under various interface reflecting modes, different transient thermal responses will occur in the media. Combined radiative-conductive heat transfer is investigated within a participating, anisotropic scattering gray planar slab. The two interfaces of the slab are considered to be diffuse and semitransparent. Using the ray tracing method, an anisotropic scattering radiative transfer model for diffuse reflection at boundaries is set up, and with the help of direct radiative transfer coefficients, corresponding radiative transfer coefficients (RTCs) are deduced. RTCs are used to calculate the radiative source term in energy equation. Transient energy equation is solved by the full implicit control-volume method under the external radiative-convective boundary conditions. The influences of two reflecting modes including both specular reflection and diffuse reflection on transient temperature fields and steady heat flux are examined. According to numerical results obtained in this paper, it is found that there exits great difference in thermal behavior between slabs with diffuse interfaces and that with specular interfaces for slabs with big refractive index

  11. Stochastic Programming for Fuel Supply Planning of Combined Heat and Power Plants

    DEFF Research Database (Denmark)

    Guericke, Daniela; Blanco, Ignacio; Morales González, Juan Miguel

    The consumption of biomass to produce power and heat has increased due to the carbon neutral policies. Combined heat and power (CHP) plants often combine biomass with other fuels, e.g., natural gas. The negotiation process for supply contracts involves many uncertainties due to the long planning...... horizon. The demand for biomass is uncertain, and heat demand and electricity prices vary during the planning period. We propose a method using stochastic optimization to support the biomass and natural gas supply planning for CHP plants including short-term decisions for optimal market participation....

  12. Modeling and optimization of a heat-pump-assisted high temperature proton exchange membrane fuel cell micro-combined-heat-and-power system for residential applications

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Kær, Søren Knudsen; Nielsen, Mads Pagh

    2015-01-01

    In this study a micro-combined-heat-and-power (micro-CHP) system is coupled to a vapor-compression heat pump to fulfill the residential needs for heating (space heating and water heating) and electricity in detached single-family households in Denmark. Such a combination is assumed to be attractive...... for application, since both fuel cell technology and electric heat pumps are found to be two of the most efficient technologies for generation/conversion of useful energy. The micro-CHP system is fueled with natural gas and includes a fuel cell stack, a fuel processor and other auxiliary components. The micro......-CHP system assumes heat-led operation, to avoid dumping of heat and the use of complicated thermal energy storage. The overall system is grid-interconnected to allow importing and exporting of electricity as necessary. In this study emphasis is given on the operational characterization of the system...

  13. Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant; Kombineret brugsvands- og rumvarmepumpe med CO{sub 2} som koelemiddel

    Energy Technology Data Exchange (ETDEWEB)

    Schoen Poulsen, C. [Teknologisk Institut (Denmark)

    2006-05-19

    This project report describes the implementation of the Danish project called 'Combined heat pump for sanitary hot water and space heating with CO{sub 2} as refrigerant'. In the course of the project, a combined heat pump has been developed for heating sanitary hot water and producing domestic space heating. The project shows that CO2 has excellent properties in systems where a high temperature is desired on the gas cooler side and that it is possible to combine the production of sanitary hot water with the production of domestic space heating. During the project, a number of system solutions have been analysed and at the end of the project a prototype was built. It was tested in the laboratory according to a current Dutch standard for heat pumps for sanitary hot water. The prototype was constructed without the space heat part which solely has been analysed according to calculations. The reason is that there currently are no applicable European standards for the testing of combined systems and as the total efficiency of the system mainly depends on the temperature out of the gas cooler it was decided not to spend resources on the construction of the combined system in the prototype version of the unit. Instead, a number of proposals have been submitted to how the system with a space heat section could be constructed. The main components used in the prototype (compressor, exchangers, valve, control and tank) are all partly commercially available and therefore focus has been on the system construction. During the project, a number of CFD calculations have been carried out on the gas cooler in the hot water tank and the results show how important it is that the gas cooler is designed and placed correctly. The laboratory tests carried out on the unit show that the COP of the heat pump plant in connection with sanitary hot water tapping (according to Dutch standard) is 1.4 1.5 which is not immediately satisfactory. But when it is considered that the unit is a

  14. Chemical studies on the influence of a combined process of heat and irradiation on carbohydrates, proteins and amino acids of dates

    International Nuclear Information System (INIS)

    Auda, H.; Nasser, L.K.

    1981-01-01

    Chemical studies were conducted on the combined effects of heat and radiation on dates. The major sugars of dates were identified using gas chromatography. Total reducing carbohydrates were determined colorometrically. In general the stability of carbohydrates was observed throughout the experimental conditions where 40 0 C and 0.5 to 1 kGy were applied. Five sugars were detected by gas chromatography in both the control and the treated samples. The major three were identified to be fructose, glucose and sucrose with retention times of 2.3, 3.3 and 5.5 min, respectively. The influence of the combination treatments on protein and amino acids was also studied. The results show that proteins in dates are stable even at a 1-kGy dose and at 40 0 C. However, individual amino acids varied in their sensitivity to heat and this variation depended entirely on the individual amino acids. (author)

  15. Cost allocation. Combined heat and power production

    International Nuclear Information System (INIS)

    Sidzikauskas, V.

    2002-01-01

    The benefits of Combined Heat and Power (CHP) generation are discussed. The include improvement in energy intensity of 1% by 2010, 85-90% efficiency versus 40-50% of condensation power and others. Share of CHP electricity production in ERRA countries is presented.Solutions for a development CHP cost allocation are considered. Conclusion are presented for CHP production cost allocation. (R.P.)

  16. Annual CO-emissions of combined pellet and solar heating systems

    OpenAIRE

    Fiedler, Frank; Persson, Tomas

    2007-01-01

    Emissions are an important aspect of a pellet heating system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner when the burner is operated below the lowest combustion power. Combining pellet heating systems with a solar heating system can significantly reduce cycling of the pellet heater and avoid the inefficient summer operation of the pellet heater. The aim of this paper was to study CO-emissions of the different types of systems and to compare the yearly...

  17. Creating markets for combined heat and power and clean distributed generation in New York State

    International Nuclear Information System (INIS)

    Bourgeois, Thomas G.; Hedman, Bruce; Zalcman, Fred

    2003-01-01

    Combined heat and power has been indentified as a central component in state and national energy strategy to lower power prices and reduce environmental impacts. - Combined heat and power (CHP) is the simultaneous production of electrical or mechanical power and thermal energy from in a single process. Because thermal output from the generation of electricity is captured and utilized onsite, CHP systems can achieve efficiencies from 60% to as high as 90%. In contrast generation of electric power at sites remote from the loads served often results in efficiencies of 33% or less due to losses in generation and transmission and distribution of the power to ultimate end users. A well designed CHP system is the essence of energy efficiency. It may also provide significant environmental benefits. However, the full promise of CHP for improving the efficiency and productivity of businesses and the quality of the environment is unlikely to be realized given the current market structure and regulatory environment in which CHP projects are forced to compete. This paper examines the market structure and regulatory obstacles that hinder the development of more robust markets for CHP in New York State

  18. Energy Optimization for Transcritical CO2 Heat Pump for Combined Heating and Cooling and Thermal Storage Applications

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Blarke, Morten; Yazawa, Kazuaki

    2012-01-01

    A transcritical heat pump (THP) cycle using carbon dioxide (CO2) as the refrigerant is known to feature an excellent coefficient of performance (COP) as a thermodynamic system. Using this feature, we are designing and building a system that combines a water-to-water CO2 heat pump with both hot....... The usability and the cost effectiveness are critical for smart grid policies on large-scale integration of intermittent renewables. In this paper, we present an analytic thermodynamic model that predicts the effect of temperature and flow rate of hot and cold water circulation on system COP. The analytical...

  19. Swiss energy research program on heat-pumps, combined heat and power and refrigeration for 2008-2011; Energieforschungsprogramm. Waermepumpen, Waerme-Kraft-Kopplung, Kaelte fuer die Jahre 2008-2011

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, T. [Hochschule fuer Technik HSR, Rapperswil (Switzerland); Eckmanns, A. [Swiss Federal Office of Energy (OFEN), Berne (Switzerland)

    2009-07-15

    This report published by the Swiss Federal Office of Energy (SFOE) takes a look at the research programme on heat-pumps, combined heat and power and refrigeration for the years 2008 - 2011. Work proposed for the years 2008 - 2011 involves the following topics: Improvement of components and the thermodynamic cycles of heat pumps and refrigeration plants as well as the improvements in the efficiency of cogeneration plants and the reduction of emission of pollutants. Also, the overall optimisation of total systems is to be examined. Highly-efficient systems for sanitary hot water production are to be looked at, as are miniaturisation and new solutions for the installation of heating and cooling systems with heat pumps. Also the development of environmental-friendly working fluids for heat pumps and refrigeration plants is planned. Pilot and demonstration projects are also to be supported in all areas.

  20. The response of previously irradiated mouse skin to heat alone or combined with irradiation: influence of thermotolerance

    International Nuclear Information System (INIS)

    Wondergem, J.; Haveman, J.

    1983-01-01

    The effect of previous x-irradiation on the response to hyperthermia (44 0 C), x-irradiation, and irradiation combined with hyperthermia (43 0 C or 44 0 C) was studied in mouse foot skin. Irradiation of mice feet 90 days before, with 20 Gy, increased the subsequent response to heat alone, or combined with irradiation, as well as to irradiation alone. It had little effect on the thermal enhancement ratios for both acute and late skin reactions. Memory of the previous irradiation treatment could be masked when the temperature of the subsequent heat treatment alone, or combined with irradiation, was 44 0 C. Priming heat treatment induced resistance to a subsequent heat treatment and to a subsequent combined irradiation-heat treatment in normal as well as previously irradiated skin. When late skin reaction was considered, a larger 'memory' of the previous irradiation treatment was always evident, compared to acute skin reaction: the 'remembered' dose in the late skin reaction was about twice the 'remembered' dose in the acute reaction. (U.K.)

  1. Technical assessment of electric heat boosters in low-temperature district heating based on combined heat and power analysis

    DEFF Research Database (Denmark)

    Cai, Hanmin; You, Shi; Wang, Jiawei

    2018-01-01

    This paper provides a technical assessment of electric heat boosters (EHBs) in low-energy districts. The analysis is based on a hypothetical district with 23 terraced single-family houses supplied by both a lowtemperature district heating (LTDH) network and a low-voltage network (LVN). Two case...

  2. Combined heat and power economic dispatch by harmony search algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Vasebi, A.; Bathaee, S.M.T. [Power System Research Laboratory, Department of Electrical and Electronic Engineering, K.N.Toosi University of Technology, 322-Mirdamad Avenue West, 19697 Tehran (Iran); Fesanghary, M. [Department of Mechanical Engineering, Amirkabir University of Technology, 424-Hafez Avenue, Tehran (Iran)

    2007-12-15

    The optimal utilization of multiple combined heat and power (CHP) systems is a complicated problem that needs powerful methods to solve. This paper presents a harmony search (HS) algorithm to solve the combined heat and power economic dispatch (CHPED) problem. The HS algorithm is a recently developed meta-heuristic algorithm, and has been very successful in a wide variety of optimization problems. The method is illustrated using a test case taken from the literature as well as a new one proposed by authors. Numerical results reveal that the proposed algorithm can find better solutions when compared to conventional methods and is an efficient search algorithm for CHPED problem. (author)

  3. Combined cycle power plant with integrated low temperature heat (LOTHECO)

    International Nuclear Information System (INIS)

    Kakaras, E.; Doukelis, A.; Leithner, R.; Aronis, N.

    2004-01-01

    The major driver to enhance the efficiency of the simple gas turbine cycle has been the increase in process conditions through advancements in materials and cooling methods. Thermodynamic cycle developments or cycle integration are among the possible ways to further enhance performance. The current paper presents the possibilities and advantages from the LOTHECO natural gas-fired combined cycle concept. In the LOTHECO cycle, low-temperature waste heat or solar heat is used for the evaporation of injected water droplets in the compressed air entering the gas turbine's combustion chamber. Following a description of this innovative cycle, its advantages are demonstrated by comparison between different gas turbine power generation systems for small and large-scale applications, including thermodynamic and economic analysis. A commercial gas turbine (ALSTOM GT10C) has been selected and computed with the heat mass balance program ENBIPRO. The results from the energy analysis are presented and the features of each concept are discussed. In addition, the exergy analysis provides information on the irreversibilities of each process and suggested improvements. Finally, the economic analysis reveals that the combined cycle plant with a heavy-duty gas turbine is the most efficient and economic way to produce electricity at base load. However, on a smaller scale, innovative designs, such as the LOTHECO concept, are required to reach the same level of performance at feasible costs

  4. The capacity credit of micro-combined heat and power

    International Nuclear Information System (INIS)

    Hawkes, A.D.; Leach, M.A.

    2008-01-01

    This article is concerned with development of a methodology to determine the capacity credit of micro-combined heat and power (micro-CHP), and application of the method for the UK. Capacity credit is an important parameter in electricity system planning because it measures the amount of conventional generation that would be displaced by an alternative technology. Firstly, a mathematical formulation is presented. Capacity credit is then calculated for three types of micro-CHP units-Stirling engine, internal combustion engine, and fuel cell systems-operating under various control strategies. It is found that low heat-to-power ratio fuel cell technologies achieve the highest capacity credit of approximately 85% for a 1.1 GW penetration when a heat-led control strategy is applied. Higher heat-to-power ratio Stirling engine technology achieves approximately 33% capacity credit for heat-led operation. Low heat-to-power ratio technologies achieve higher capacity credit because they are able to continue operating even when heat demand is relatively low. Capacity credit diminishes as penetration of the technology increases. Overall, the high capacity credit of micro-CHP contributes to the viewpoint that the technology can help meet a number of economic and environmental energy policy aims

  5. Influence of dimethyl dicarbonate on the resistance of Escherichia coli to a combined UV-Heat treatment in apple juice

    Science.gov (United States)

    Gouma, Maria; Gayán, Elisa; Raso, Javier; Condón, Santiago; Álvarez, Ignacio

    2015-01-01

    Commercial apple juice inoculated with Escherichia coli was treated with UV-C, heat (55°C) and dimethyl dicarbonate – DMDC (25, 50, and 75 mg/L)-, applied separately and in combination, in order to investigate the possibility of synergistic lethal effects. The inactivation levels resulting from each treatment applied individually for a maximum treatment time of 3.58 min were limited, reaching 1.2, 2.9, and 0.06 log10 reductions for UV, heat, and DMDC (75 mg/L), respectively. However, all the investigated combinations resulted in a synergistic lethal effect, reducing the total treatment time and UV dose, with the synergistic lethal effect being higher when larger concentrations of DMDC were added to the apple juice. The addition of 75 mg/L of DMDC prior to the combined UV-C light treatment at 55°C resulted in 5 log10 reductions after only 1.8 min, reducing the treatment time and UV dose of the combined UV-Heat treatment by 44%. PMID:26042117

  6. An experimental study of the effects of combined exposure to microwave and heat on gene expression and sperm parameters in mice

    Directory of Open Access Journals (Sweden)

    Faezeh A Gohari

    2017-01-01

    Full Text Available Objectives: Separate exposure to microwaves (MWs or heat had effects on expression levels of Bax and Bcl-2 and sperm parameters in studied group. Aims: The objectives of this research were to determine the effects of separate and combined exposure to 900-MHz MW (as representative of cell phone radiation and heat on gene expression and spermogram of male mice. Settings and Design: This experimental animal study was conducted in the school of public health. Materials and Methods: The study was done on 12 male mice randomly divided into four groups (21–23 g: control, test group 1 with separate exposure to 900-MHz MW, test group 2 with separate exposure to hot and sultry climate, and test group 3 with simultaneous whole body exposures to 900-MHz MW and hot and sultry climate. In all studied groups, gene expression and sperm parameters were measured. Results: Tissue samples in all test groups showed integrity of the seminiferous tubule followed by all types of germ line cells. Significant increases in the number of dead sperms in mice with separate exposure to heat were observed in comparison with the other studied groups (P < 0.05. The ratio of Bax expression was elevated to 0.015 ± 0.006 in mice after combined exposures to 900-MHz MW and heat. Conclusion: Separate and combined exposure to 900-MHz MW and heat may induce adverse effects on sperm parameters and gene expression of studied male mice.

  7. Effects of Combined Heat and Preservative Treatment on Storability of Ponkan Fruit (Citrus reticulata Blanco cv. Ponkan during Postharvest Storage

    Directory of Open Access Journals (Sweden)

    Dandan Tang

    2017-01-01

    Full Text Available Heat treatment and preservative application have been widely used during postharvest storage of many fresh products, but the effect of their combination on citrus storage has rarely been investigated. In this study, the optimal heat treatment (HT conditions and HT combined with preservative treatment were investigated for Ponkan fruit (Citrus reticulata Blanco cv. Ponkan storage. Results indicated that HT at 55°C for 20 s can significantly reduce the decay rate of Ponkan fruit, and a combination of HT and 25% of the preservative dosage used in production of iminoctadine tris (albesilate, 2,4-dichlorophenoxyacetic acid, and imazalil significantly reduced the decay rate without affecting fruit quality. In addition, the increased fiber contents in fruit receiving the HT combined with preservative treatments may be a response preventing fungus infection and enhancing fruit storability and resistance. The above results suggested that the combination of HT and 25% of the preservative production dosage was optimal for controlling Ponkan fruit decay during storage.

  8. Combination of a gas heat pump with geothermal energy and solar heat utilisation; Kombination einer Gaswaermepumpe mit Geothermie und Solarwaermenutzung

    Energy Technology Data Exchange (ETDEWEB)

    Peter, Andreas [Robur GmbH, Friedrichshafen (Germany)

    2009-01-15

    A home for handicapped persons in Berlin was modernised. This included the installation of a gas-fuelled absorption heat pump combined with geothermal heat supply and solar heating. CO2 emissions and primary energy consumption were reduced considerably by this concept. (orig.)

  9. Combined heat and power economic dispatch by a fish school search algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Leonardo Trigueiro dos; Costa e Silva, Marsil de Athayde [Undergraduate in Mechatronics Engineering, Pontifical Catholic University of Parana, Curitiba, PR (Brazil); Coelho, Leandro dos Santos [Industrial and Systems Engineering Graduate Program, PPGEPS, Pontifical Catholic University of Parana, Curitiba, PR (Brazil)], e-mail: leandro.coelho@pucpr.br

    2010-07-01

    The conversion of primary fossil fuels, such as coal and gas, to electricity is a a relatively inefficient process. Even the most modern combined cycle plants can only achieve efficiencies of between 50-60%. A great portion of the energy wasted in this conversion process is released to the environment as waste heat. The principle of combined heat and power, also known as cogeneration, is to recover and make beneficial use of this heat, significantly raising the overall efficiency of the conversion process. However, the optimal utilization of multiple combined heat and power systems is a complicated problem which needs powerful methods to solve. This paper presents a fish school search (FSS) algorithm to solve the combined heat and power economic dispatch problem. FSS is a novel approach recently proposed to perform search in complex optimization problems. Some simulations presented in the literature indicated that FSS can outperform many bio-inspired algorithms, mainly in multimodal functions. The search process in FSS is carried out by a population of limited-memory individuals - the fishes. Each fish represents a possible solution to the problem. Similarly to particle swarm optimization or genetic algorithm, search guidance in FSS is driven by the success of some individual members of the population. A four-unit system proposed recently which is a benchmark case in the power systems field has been validated as a case study in this paper. (author)

  10. Deep Heat Mining - Development of the hot dry rock and hot wet rock technologies for power and heat production in Switzerland; Deep Heat Mining. Entwicklung der Hot-Dry-Rock / Hot-Wet-Rock Technologie zur Strom- und Waermeproduktion in der Schweiz, insbesondere Deep Heat Mining, Basel

    Energy Technology Data Exchange (ETDEWEB)

    Haering, M. O.; Hopkirk, R. J.

    2003-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the progress and achievements made for two heat mining projects in Basle and Geneva. Work initialised at further sites in southern Switzerland and in the Bernese 'Oberland' alpine area is also mentioned. Project organisation and planning topics are examined. Seismic monitoring aspects are discussed and first practical studies on using the geothermal heat in Basle using hybrid energy conversion systems are discussed. For the Geneva project, details on site selection are given and ideas on combined geothermal and gas turbine plant are discussed.

  11. Effect of heat treatment oanas irradiation, and combined treatment on the shelf of fresh avocados (Persea americana L)

    International Nuclear Information System (INIS)

    Purwanto, Z.I.; Maha, Munsiah

    1987-01-01

    Effects of heat treatment, gamma irradiation, and combined treatments on the shelf-life of fresh avocados (Persea americana L.). Experiments to determine the effective irradiation conditions to prolong the shelf-life of fresh avocados were conducted at the centre for the Application of Isotopes washed and dried, then divided into 4 groups, namely for control (A), dipped in hot water at 40 0 C for 20 minutes (heat treatment, B), irradiated at a dose of 25 Gy (C), and combination of hot water dipping (40 0 C for 20 minutes) and irradiation at a 25 Gy (D). The samples were stored at room temperature. Evaluation on physical and chemical properties of the samples was done daily up to 10 days' storage. Parameters observed were texture, moisture and fat contents, percentage of weight loss, percentage of mature fruit, and subjective organoleptic evaluation. It was found that treated samples with and without combination treatment were still in good condition until 10 days of storage. It could be concluded that dipping in hot water, either alone or in combination with irradiation at a dose of 25 Gy could extend the shelf-life of fresh avocado up to 10 days at room temperature compared to only 5 days of the control. (author). 2 figs, 8 refs

  12. 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

    2015-05-01

    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.

  13. Methods for planning and operating decentralized combined heat and power plants

    Energy Technology Data Exchange (ETDEWEB)

    Palsson, H.

    2000-02-01

    In recent years, the number of decentralized combined heat and power (DCHP) plants, which are typically located in small communities, has grown rapidly. These relatively small plants are based on Danish energy resources, mainly natural gas, and constitute an increasing part of the total energy production in Denmark. The topic of this thesis is the analysis of DCHP plants, with the purpose to optimize the operation of such plants. This involves the modelling of district heating systems, which are frequently connected to DCHP plants, as well as the use of heat storage for balancing between heat and power production. Furthermore, the accumulated effect from increasing number of DCHP plants on the total power production is considered. Methods for calculating dynamic temperature response in district heating (DH) pipes have been reviewed and analyzed numerically. Furthermore, it has been shown that a tree-structured DH network consisting of about one thousand pipes can be reduced to a simple chain structure of ten equivalent pipes without loosing much accuracy when temperature dynamics are calculated. A computationally efficient optimization method based on stochastic dynamic programming has been designed to find an optimum start-stop strategy for a DCHP plant with a heat storage. The method focuses on how to utilize heat storage in connection with CHP production. A model for the total power production in Eastern Denmark has been applied to the accumulated DCHP production. Probability production simulations have been extended from the traditional power-only analysis to include one or several heat supply areas. (au)

  14. Customer adoption of small-scale on-site power generation

    Energy Technology Data Exchange (ETDEWEB)

    Siddiqui, Afzal S.; Marnay, Chris; Hamachi, Kristina S.; Rubio, F. Javier

    2001-04-01

    The electricity supply system is undergoing major regulatory and technological change with significant implications for the way in which the sector will operate (including its patterns of carbon emissions) and for the policies required to ensure socially and environmentally desirable outcomes. One such change stems from the rapid emergence of viable small-scale (i.e., smaller than 500 kW) generators that are potentially competitive with grid delivered electricity, especially in combined heat and power configurations. Such distributed energy resources (DER) may be grouped together with loads in microgrids. These clusters could operate semi-autonomously from the established power system, or macrogrid, matching power quality and reliability more closely to local end-use requirements. In order to establish a capability for analyzing the effect that microgrids may have on typical commercial customers, such as office buildings, restaurants, shopping malls, and grocery stores, an economic mod el of DER adoption is being developed at Berkeley Lab. This model endeavors to indicate the optimal quantity and type of small on-site generation technologies that customers could employ given their electricity requirements. For various regulatory schemes and general economic conditions, this analysis produces a simple operating schedule for any installed generators. Early results suggest that many commercial customers can benefit economically from on-site generation, even without considering potential combined heat and power and reliability benefits, even though they are unlikely to disconnect from the established power system.

  15. Customer adoption of small-scale on-site power generation

    International Nuclear Information System (INIS)

    Siddiqui, Afzal S.; Marnay, Chris; Hamachi, Kristina S.; Rubio, F. Javier

    2001-01-01

    The electricity supply system is undergoing major regulatory and technological change with significant implications for the way in which the sector will operate (including its patterns of carbon emissions) and for the policies required to ensure socially and environmentally desirable outcomes. One such change stems from the rapid emergence of viable small-scale (i.e., smaller than 500 kW) generators that are potentially competitive with grid delivered electricity, especially in combined heat and power configurations. Such distributed energy resources (DER) may be grouped together with loads in microgrids. These clusters could operate semi-autonomously from the established power system, or macrogrid, matching power quality and reliability more closely to local end-use requirements. In order to establish a capability for analyzing the effect that microgrids may have on typical commercial customers, such as office buildings, restaurants, shopping malls, and grocery stores, an economic mod el of DER adoption is being developed at Berkeley Lab. This model endeavors to indicate the optimal quantity and type of small on-site generation technologies that customers could employ given their electricity requirements. For various regulatory schemes and general economic conditions, this analysis produces a simple operating schedule for any installed generators. Early results suggest that many commercial customers can benefit economically from on-site generation, even without considering potential combined heat and power and reliability benefits, even though they are unlikely to disconnect from the established power system

  16. Study on the Optimizing Operation of Exhaust Air Heat Recovery and Solar Energy Combined Thermal Compensation System for Ground-Coupled Heat Pump

    Directory of Open Access Journals (Sweden)

    Kuan Wang

    2017-01-01

    Full Text Available This study proposed an exhaust air heat recovery and solar energy combined thermal compensation system (ESTC for ground-coupled heat pumps. Based on the prediction of the next day’s exhaust air temperature and solar irradiance, an optimized thermal compensation (OTC method was developed in this study as well, in which the exhaust air heat recovery compensator and solar energy compensator in the ESTC system run at high efficiency throughout various times of day. Moreover, a modified solar term similar days group (STSDG method was proposed to improve the accuracy of solar irradiance prediction in hazy weather. This modified STSDG method was based on air quality forecast and AQI (air quality index correction factors. Through analyzing the operating parameters and the simulation results of a case study, the ESTC system proved to have good performance and high efficiency in eliminating the heat imbalance by using the OTC method. The thermal compensation quantity per unit energy consumption (TEC of ESTC under the proposed method was 1.25 times as high as that under the traditional operation method. The modified STSDG method also exhibited high accuracy. For the accumulated solar irradiance of the four highest daily radiation hours, the monthly mean absolute percentage error (MAPE between the predicted values and the measured values was 6.35%.

  17. A new multi-objective reserve constrained combined heat and power dynamic economic emission dispatch

    International Nuclear Information System (INIS)

    Niknam, Taher; Azizipanah-Abarghooee, Rasoul; Roosta, Alireza; Amiri, Babak

    2012-01-01

    Combined heat and power units are playing an ever increasing role in conventional power stations due to advantages such as reduced emissions and operational cost savings. This paper investigates a more practical formulation of the complex non-convex, non-smooth and non-linear multi-objective dynamic economic emission dispatch that incorporates combined heat and power units. Integrating these types of units, and their power ramp constraints, require an efficient tool to cope with the joint characteristics of power and heat. Unlike previous approaches, the spinning reserve requirements of this system are clearly formulated in the problem. In this way, a new multi-objective optimisation based on an enhanced firefly algorithm is proposed to achieve a set of non-dominated (Pareto-optimal) solutions. A new tuning parameter based on a chaotic mechanism and novel self adaptive probabilistic mutation strategies are used to improve the overall performance of the algorithm. The numerical results demonstrate how the proposed framework was applied in real time studies. -- Highlights: ► Investigate a practical formulation of the DEED (Dynamic Economic Emission Dispatch). ► Consider combined heat and power units. ► Consider power ramp constraints. ► Consider the system spinning reserve requirements. ► Present a new multi-objective optimization firefly.

  18. Monitoring of Danish marketed solar heating systems

    International Nuclear Information System (INIS)

    Ellehauge, K.

    1993-01-01

    The paper describes the monitoring of manufactured solar heating systems for domestic hot water combined with space heating and systems for domestic hot water only. Results from the monitoring of 5 marketed combined systems for domestic hot water and space heating are presented. The systems situated at one family houses at different sites in Denmark have been monitored from January/February 1992. For the detailed monitoring of manufactured systems only for domestic hot water a test facility for simultaneous monitoring of 5 solar heating systems has been established at the Thermal Insulation Laboratory. (au)

  19. [Effects of the combined therapy of heat sensitive moxibustion and acupoint injection on endometrial receptivity of hypdrosalphinx infertility in the patients after hysteroscopy and laparoscopy].

    Science.gov (United States)

    Liu, Yanling; Pan, Lizhen; Wang, Ying

    2018-01-12

    To explore the effects of the combined therapy of heat sensitive moxibustion and acupoint injection on endometrial receptivity of hypdrosalphinx infertility in the patients after hysteroscopy and laparoscopy on the base of routine post-operative anti-inflammation. A total of 210 patients of hypdrosalphinx infertility after hysteroscopy and laparoscopy were divided into a combined therapy group, a heat sensitive moxibustion group and a control group, 70 cases in each one according to the random number table. In the control group, the intravenous drip of cefoxitin sodium was adopted, and the anti-inflammation treatment was given for 1 week after operation. In the heat sensitive moxibustion group, on the basis of the treatment as the control group, the heat sensitive moxibustion was applied after vaginal bleeding stopped. The acupoints were Yaoyangguan (GV 3), Guanyuan (CV 4), Qihai (CV 6), Shenshu (BL 23), Sanyinjiao (SP 6), Yinlingquan (SP 9) and Zigong (EX-CA1). The acupoints were modified according to the different syndromes. In the combined therapy group, on the basis of the regimen as the heat sensitive moxibustion group, after vaginal bleeding stopped, the acupoint injection was given alternatively at bilateral Tiangong (extra, 1.0 cm inferior and bilateral to the cervix) with lidocaine 1 mL, amikacin 2 mL and salvia injection 2 mL. The treatment was given once every day, the treatment for 10 times as one course and a total of 3 courses were required. The endometrial type, thickness, uterine arterial plusatility index (PI) and resistance index (RI) were observed in the patients of each group. After treatment, the numbers of A-type endometrial type in the combined therapy group and the heat sensitive moxibustion group were remarkably higher than those of the control group [57.1% (40/7) vs 31.4% (22/70), 50.0% (35/70) vs 31.4% (22/70), both P <0.05]. The endometrial thickness after treatment was all increased as compared with that before treatment in each group

  20. Heat recovery subsystem and overall system integration of fuel cell on-site integrated energy systems

    Science.gov (United States)

    Mougin, L. J.

    1983-01-01

    The best HVAC (heating, ventilating and air conditioning) subsystem to interface with the Engelhard fuel cell system for application in commercial buildings was determined. To accomplish this objective, the effects of several system and site specific parameters on the economic feasibility of fuel cell/HVAC systems were investigated. An energy flow diagram of a fuel cell/HVAC system is shown. The fuel cell system provides electricity for an electric water chiller and for domestic electric needs. Supplemental electricity is purchased from the utility if needed. An excess of electricity generated by the fuel cell system can be sold to the utility. The fuel cell system also provides thermal energy which can be used for absorption cooling, space heating and domestic hot water. Thermal storage can be incorporated into the system. Thermal energy is also provided by an auxiliary boiler if needed to supplement the fuel cell system output. Fuel cell/HVAC systems were analyzed with the TRACE computer program.

  1. Techno-economic analysis of a coal-fired CHP based combined heating system with gas-fired boilers for peak load compensation

    International Nuclear Information System (INIS)

    Wang Haichao; Jiao Wenling; Lahdelma, Risto; Zou Pinghua

    2011-01-01

    Combined heat and power (CHP) plants dominate the heating market in China. With the ongoing energy structure reformation and increasing environmental concerns, we propose gas-fired boilers to be deployed in underperforming heating substations of heating networks for peak load compensation, in order to improve both energy efficiency and environmental sustainability. However, due to the relatively high price of gas, techno-economic analysis is required for evaluating different combined heating scenarios, characterized by basic heat load ratio (β). Therefore, we employ the dynamic economics and annual cost method to develop a techno-economic model for computing the net heating cost of the system, considering the current state of the art of cogeneration systems in China. The net heating cost is defined as the investment costs and operations costs of the system subtracted by revenues from power generation. We demonstrate the model in a real-life combined heating system of Daqing, China. The results show that the minimum net heating cost can be realized at β=0.75 with a cost reduction of 16.8% compared to coal heating alone. Since fuel cost is the dominating factor, sensitivity analyses on coal and gas prices are discussed subsequently. - Highlights: ► Combined heating systems comply with the energy structure reformation in China. ► We consider the current state of the art of cogeneration systems in China. ► Combined heating systems can be economically more feasible and sustainable. ► The net heating cost of a combined heating system is more sensitive to coal price. ► The optimal basic heat load ratio is more easily influenced by gas price.

  2. Nuclear combined cycle gas turbines for variable electricity and heat using firebrick heat storage and low-carbon fuels

    International Nuclear Information System (INIS)

    Forsberg, Charles; Peterson, Per F.; McDaniel, Patrick; Bindra, Hitesh

    2017-01-01

    The world is transitioning to a low-carbon energy system. Variable electricity and industrial energy demands have been met with storable fossil fuels. The low-carbon energy sources (nuclear, wind and solar) are characterized by high-capital-costs and low-operating costs. High utilization is required to produce economic energy. Wind and solar are non-dispatchable; but, nuclear is the dispatchable energy source. Advanced combined cycle gas turbines with firebrick heat storage coupled to high-temperature reactors may enable economic variable electricity and heat production with constant full-power reactor output. Such systems efficiently couple to fluoride-salt-cooled high-temperature reactors (FHRs) with solid fuel and clean salt coolants, molten salt reactors (MSRs) with fuel dissolved in the salt coolant and salt-cooled fusion machines. Open Brayton combined cycles allow the use of natural gas, hydrogen, other fuels and firebrick heat storage for peak electricity production with incremental heat-to-electricity efficiencies from 66 to 70+% efficient. There are closed Brayton cycle options that use firebrick heat storage but these have not been investigated in any detail. Many of these cycles couple to high-temperature gas-cooled reactors (HTGRs). (author)

  3. Floor heating and cooling combined with displacement ventilation: Possibilities and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Causone, Francesco; Corgnati, Stefano P. [TEBE Research Group, Department of Energetics, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Baldin, Fabio [Department of Applied Physics, University of Padova, via Venezia 1, 35131 Padova (Italy); Olesen, Bjarne W. [ICIEE, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle Building 402, 2800 Kgs. Lyngby (Denmark)

    2010-12-15

    Design guidelines envisage that floor heating can be used together with displacement ventilation (DV), provided that the supply air is not overly heated before it can reach heat and contaminant sources. If this is not controlled a mixing flow pattern could occur in the room. The use of floor cooling with DV is also considered possible, although draught risk at ankle level and vertical air temperature differences must be controlled carefully, because they could increase. Few studies on these topics were found in the literature. An indoor environmental chamber was set up to obtain measurements aimed at analysing the possibilities and limitations of combining floor heating/cooling with DV. Air temperature profiles, air velocity profiles, surface temperatures and ventilation effectiveness were measured under different environmental conditions that may occur in practice. These values were compared to equivalent temperature measurements obtained using a thermal manikin. The measurements show that floor heating can be used with DV, obtaining high ventilation effectiveness values. A correlation between the floor heating capacity and the air temperature profile in the room was found. Measurements showed that floor cooling does not increase draught risk at ankle level, although it does increase vertical air temperature differences. (author)

  4. Combined heat and power and solar energy; BHKW und solare Energie

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, M.; Schmidt, A.

    2006-07-01

    This illustrated article takes a look at a new apartment complex in Buelach, Switzerland, that meets the 'Minergie' low energy-consumption standard and also features solar-thermal heat generation. This solar installation provides heat for the provision of domestic hot water and, also, heat for the space-heating system of the building complex. The solar collectors cover an area of 153 m{sup 2}; their power is rated at 96 kW. Further elements of the building's technical services include a combined heat and power plant, a heat-pump and a gas-fired boiler. The article discusses ecological and social aspects of the design and construction of the building complex and briefly describes the installations, which also include a 'Minergie' fan-assisted balanced ventilation system.

  5. Combined heat and power (cogeneration) plant based on renewable energy sources and electrochemical hydrogen systems

    Science.gov (United States)

    Grigor'ev, S. A.; Grigor'ev, A. S.; Kuleshov, N. V.; Fateev, V. N.; Kuleshov, V. N.

    2015-02-01

    The layout of a combined heat and power (cogeneration) plant based on renewable energy sources (RESs) and hydrogen electrochemical systems for the accumulation of energy via the direct and inverse conversion of the electrical energy from RESs into the chemical energy of hydrogen with the storage of the latter is described. Some efficient technical solutions on the use of electrochemical hydrogen systems in power engineering for the storage of energy with a cyclic energy conversion efficiency of more than 40% are proposed. It is shown that the storage of energy in the form of hydrogen is environmentally safe and considerably surpasses traditional accumulator batteries by its capacitance characteristics, being especially topical in the prolonged absence of energy supply from RESs, e.g., under the conditions of polar night and breathless weather. To provide the required heat consumption of an object during the peak period, it is proposed to burn some hydrogen in a boiler house.

  6. Optimization of systems with the combination of ground-source heat pump and solar collectors in dwellings

    DEFF Research Database (Denmark)

    Kjellsson, Elisabeth; Hellström, Göran; Perers, Bengt

    2010-01-01

    The use of ground-source heat pumps for heating and domestic hot water in dwellings is common in Sweden. The combination with solar collectors has been introduced to reduce the electricity demand in the system. In order to analyze different systems with combinations of solar collectors and ground......-source heat pumps, computer simulations have been carried out with the simulation program TRNSYS. Large differences were found between the system alternatives. The optimal design is when solar heat produces domestic hot water during summertime and recharges the borehole during wintertime. The advantage...... is related to the rate of heat extraction from the borehole as well as the overall design of the system. The demand of electricity may increase with solar recharging, because of the increased operating time of the circulation pumps. Another advantage with solar heat in combination with heat pumps is when...

  7. Marketing research on heat storage in aquifers. Systems, applications and combinations with heat generating techniques, and sector potentials. Marktorientatie warmte-opslag in aquifers. Systemen, toepassingen en combinaties met warmte-producerende technieken, deelsector potentielen

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    The market research on the title subject concentrates on the possible applications of seasonal heat storage for space heating in buildings (not industrial). Some selected heat storage systems in aquifers were analyzed with regard to the state of the technology, minimal storage capacity and the price/performance ratio. Then a number of co binations with bridging techniques has been investigated: combinations with cogeneration systems, heat pumps or solar energy systems. Finally the potentials of energy conservation in non-industrial buildings for small-scale and large-scale heat storage are listed. 6 figs., 16 refs., 24 tabs., 9 apps.

  8. Thermal interaction effect on nucleation site distribution in subcooled boiling

    International Nuclear Information System (INIS)

    Zou, Ling; Jones, Barclay

    2012-01-01

    An experimental work on subcooled boiling of refrigerant, R134a, to examine nucleation site distributions on both copper and stainless steel heating surfaces was performed. In order to obtain high fidelity active nucleation site density and distribution data, a high-speed digital camera was utilized to record bubble emission images from a view normal to heating surfaces. Statistical analyses on nucleation site data were done and their statistical distributions were obtained. Those experimentally observed nucleation site distributions were compared to the random spatial Poisson distribution. The comparisons showed that, rather than purely random, active nucleation site distributions on boiling surfaces are relatively more uniform. Experimental results also showed that on the copper heating surface, nucleation site distributions are slightly more uniform than on the stainless steel surface. This was concluded as the results of thermal interactions between nucleation sites with different solid thermal conductivities. A two dimensional thermal interaction model was then developed to quantitatively examine the thermal interactions between nucleation sites. The results give a reasonable explanation to the experimental observation on nucleation site distributions.

  9. Simultaneous heat and moisture transfer in soils combined with building simulation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, G. H. dos; Mendes, N. [Pontifical Catholic University of Parana, PUCPR/CCET, Thermal Systems Laboratory (LST), Curitiba (Brazil)

    2006-07-01

    In order to precisely predict ground heat transfer, room air temperature and humidity, a combined model has been developed and conceived to calculate both the coupled heat and moisture transfer in soil and floor and the psychrometrics condition of indoor air. The present methodology for the soil is based on the theory of Philip and De Vries, using variable thermophysical properties for different materials. The governing equations were discretized using the finite-volume method and a three-dimensional model for describing the physical phenomena of heat and mass transfer in unsaturated moist porous soils and floor. Additionally, a lumped transient approach for a building room and a finite-volume multi-layer model for the building envelope have been developed to integrate with the soil model. Results are presented in terms of temperature, humidity and heat flux at the interface between room air and the floor, showing the importance of the approach presented and the model robustness for long-term simulations with a high time step. (author)

  10. The combined effect of heat and gamma irradiation on the inactivation of selected microorganisms associated with food hygiene

    International Nuclear Information System (INIS)

    Kwon, O.J.; Byun, M.W.

    1996-01-01

    The bactericidal effectiveness of radiation alone or in combination with heat against 8 strains associated with food hygiene were evaluated. In the case of radiation alone, D values of micro-organisms were 0.14~0.48 kGy, and inactivation factors were 4.54~21.43 at the doses of 2~3 kGy. Escherichia coli was the most sensitive among the tested strains, resulting in a D value of 0.14 kGy. D values of tile strains were 10~40 minutes at 50±1°C and 5~10 minutes at 60±1°C. Combination with heat and radiation showed D values of 0.04~0.31. Inactivation factors were 6.45~75 at the doses of 2 to 3 kGy. Therefore, heat treatment prior to irradiation significantly increased activation rate by increasing radiation sensitivity of microorganisms

  11. Analysis of Decay Heat Removal by Natural Convection in LMR with a Combined Steam Generator

    International Nuclear Information System (INIS)

    Kim, Eui Kwang; Eoh, Jae Hyuk; Han, Ji Woong; Lee, Tae Ho

    2011-01-01

    Liquid metal reactors (LMRs) conventionally employ an intermediate heat transport system (IHTS) to protect the nuclear core during a sodium-water reaction (SWR) event. However these SWR-related components increase plant construction costs. In order to eliminate the need for an IHTS, a combined steam generator, which is an integrated heat exchanger of a steam generator and intermediate heat exchanger (IHX), was proposed by the Korea Atomic Energy Research Institute (KAERI). The objective of this work is to analyze the natural circulation heat removal capability of the rector system using a combined steam generator. As a means of decay heat removal, a normal heat transport path is composed of a primary sodium system, intermediate lead-bismuth circuit combined with SG and steam/water system. This paper presents the results of the possible temperature and natural circulation flows in all circuits during a steady state for a given reactor power level varied as a function of time

  12. Field Demonstration of Ground-Source Integrated Heat Pump Part I. Technology and Field Demo System/Site Descriptions, and Preliminary Summer/Fall Performance Analysis for One Site

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gehl, Anthony C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-01

    The field study is planned to continue through the 2016 cooling season with the draft final project report due by September 30, 2016. This report provides a description of both installations and preliminary 2015 cooling and fall season performance results for the Knoxville site. For the August 18 through December 14 period, the Knoxville site GS-IHP provided 53.6% total source energy savings compared to a baseline electric RTU/heat pump and electric WH. Peak demand savings ranged from 33% to 59% per month. Energy cost savings of 53.1% have been achieved to date with more than half of that coming from reduced demand charges. Data on installation and maintenance costs are being collected and will be combined with total test period energy savings data for a payback analysis to be included in the project final report. The GS-IHP also saved a significant amount of carbon emissions. The total emission savings for the Knoxville site for the August-December 2015 period were ~0.8 metric tons. If trading for carbon credits ever becomes a reality, additional cost savings would be realized.

  13. Experimental study of natural convection heat transfer from an isothermal combined geometry (downward cone- cylinder)

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari, A. [Yazd Univ., Yazd (Iran, Islamic Republic of). Dept. of Mechanical Engineering; Goharkhah, M.; Ashjaee, M. [Tehran Univ., Tehran (Iran, Islamic Republic of). Dept. of Mechanical Engineering

    2009-07-01

    Laminar free convection heat transfer from an isothermal combined geometry which consists of a downward cone attached to a vertical cylinder was studied. In particular, a Mach-Zehnder interferometer was used to determine the change in local and average heat transfer coefficients on the surface of an isothermal combined geometry for different vertex angles. The effect of the vertex angle on heat transfer was also investigated by keeping the height of the cylinder and slant length of the cone constant for all objects. The experimental data showed that the local heat transfer coefficient on the conical part increased in the vicinity of the cylinder and cone intersection. The distance between the point of minimum heat transfer coefficient on the cone and vertex of the cone decreased as the vertex angle increased. The maximum average Nusselt number for a constant Rayleigh number was obtained for the geometry with the smallest vertex angle. For all objects, the average Nusselt number increased with an increase in the Rayleigh number. An experiment was carried out on a vertical isothermal cylinder of circular cross section in order to validate the experimental approach. An analytical solution was found to be in good agreement with experimental results. 31 refs., 9 figs.

  14. Summary of some feasibility studies for site-specific solar industrial process heat

    Energy Technology Data Exchange (ETDEWEB)

    None

    1982-01-01

    Some feasibility studies for several different site specific solar industrial process heat applications are summarized. The followng applications are examined. Leather Tanning; Concrete Production: Lumber and Paper Processing; Milk Processing; Molding, Curing or Drying; Automobile Manufacture; and Food Processing and Preparation. For each application, site and process data, system design, and performance and cost estimates are summarized.

  15. Prospects for city-scale combined heat and power in the UK

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, John [Finnpower, High Wycombe (United Kingdom); Amos, John [Hoare Lea and Partners, Bristol (United Kingdom); Hutchinson, David [London Research Centre (United Kingdom); Denman, Malcolm [Sheffield Hallam Univ. (United Kingdom). School of Engineering

    1996-07-01

    City-scale combined heat and power/district heating (CHP/DH) brings to a number of European countries major social and commercial benefits which have been almost totally overlooked in the UK. To bring CHP/DH to the UK, it is necessary first to convince people of the benefits and then to persuade the Government to introduce the necessary legislation to allow the establishment of true city energy utilities on European lines. Neither task will be easy because of the resultant effect on the British fuel industries. The necessary changes must inevitably be gradual and there would, in any case, be a substantial role for the fuel industries - which they must be made aware of. (author)

  16. High-temperature thermocline TES combining sensible and latent heat - CFD modeling and experimental validation

    Science.gov (United States)

    Zavattoni, Simone A.; Geissbühler, Lukas; Barbato, Maurizio C.; Zanganeh, Giw; Haselbacher, Andreas; Steinfeld, Aldo

    2017-06-01

    The concept of combined sensible/latent heat thermal energy storage (TES) has been exploited to mitigate an intrinsic thermocline TES systems drawback of heat transfer fluid outflow temperature reduction during discharging. In this study, the combined sensible/latent TES prototype under investigation is constituted by a packed bed of rocks and a small amount of encapsulated phase change material (AlSi12) as sensible heat and latent heat sections respectively. The thermo-fluid dynamics behavior of the combined TES prototype was analyzed by means of a computational fluid dynamics approach. Due to the small value of the characteristic vessel-to-particles diameter ratio, the effect of radial void-fraction variation, also known as channeling, was accounted for. Both the sensible and the latent heat sections of the storage were modeled as porous media under the assumption of local thermal non-equilibrium (LTNE). The commercial code ANSYS Fluent 15.0 was used to solve the model's constitutive conservation and transport equations obtaining a fairly good agreement with reference experimental measurements.

  17. Heat-radiation combination for control of mold infection in harvested fruits and processed cereal foods

    International Nuclear Information System (INIS)

    Pawdal-Desai, S.R.; Ghanekar, A.S.; Thomas, P.; Sreenivasan, A.

    1973-01-01

    A combination of mild heat and low dose irradiation was found to extend the shelf-life of fresh fruits and processed cereal foods by controlling mold infection. Chapaties (Indian unleavened bread) and bread slices packed in polycell pouches, subjected to 50 krad followed by dry heat (65 0 C) were free from mold and shelf-stable for 10 weeks at ambient temperature (28-32 0 C). Inoculated pack studies confirmed the efficiency of the treatment. No immediate changes in organoleptic attributes were discernible even after exposure to 100 krad. The quality deterioration in sliced bread stored for 2 1/2 months has been attributed to natural staling rather than radiation. Hot water dip (50 0 C for 5 min) followed by 150 krad irradiation extended the shelf-life of fresh figs by 3-4 days at 28-32 0 C and 8-10 days at 15 0 C. Regardless of the sequence of treatments, combination of heat and 100 krad extended the shelf-life of grapes both at ambinet and refrigerated storage. In mangoes, heat followed by 50 krad was effective in controlling anthracnose and stem-end rot whereas in bananas irradiated for delayed ripening, hot water treatment can be used as a supplementary process to control stem-end rot. Quality of combination treated fruits was comparable to normally ripened fruits. In vitro studies with fungal pathogens isolated from the above fruits and cereal foods revealed that the synergistic effect of heat-radiation combination depends on the sequence of treatments which varied with respect to different pathogens studied. Some biochemical aspects of combination treated fruits is discussed. (F.J.)

  18. Evaluation of transcatheter arterial chemoembolization combined with radiofrequency capacitive heating on clinical therapeutic effect of metastatic carcinoma

    International Nuclear Information System (INIS)

    Chen Qianli; Ye Qiang; Gu Weizhong; Zhang Jiazhong; Tong Qiangang; Xi Shunfa

    2006-01-01

    Objective: To evaluate clinical therapeutic efficacy and adverse efficacy of transcatheter arterial chemoembolization (TACE) combined with radiofrequency capacitive heating (RCH) for metastatic hepatic carcinoma (MHC). Methods: Thirty-nine cases of MHC were enrolled in this study and divided into two groups: study group (n=19) and control group (n=20). Before therapy, the Karnofsky's score of the patients was all beyond 60. Results: The carcinoma growth rate of the study group was -(0.38±0.22), while that of the control group was -(0.13±0.25), showing significant statistical difference (P 0.05). Conclusion: The therapeutic effect of MHC can be further improved by the treatment of TACE combined with radiofrequency capacitive heating without increase of adverse side effects. (authors)

  19. Effectiveness of edible coatings combined with mild heat shocks on microbial spoilage and sensory quality of fresh cut broccoli (Brassica oleracea L.).

    Science.gov (United States)

    Moreira, María del R; Ponce, Alejandra; Ansorena, R; Roura, Sara I

    2011-08-01

    The use of edible coatings and mild heat shocks is proposed as postharvest treatments to prevent microbial deterioration of refrigerated broccoli. Minimally processed broccoli was coated with either chitosan or carboxymethyl-cellulose (CMC) combined or not with a previous application of a mild heat shock. The evolution of microbial populations (mesophilic, psycrotrophic, Enterobacteriaceae, molds and yeast, and lactic acid bacteria) was studied during 20 d of storage and fitted to Gompertz and logistic models. Results revealed that, at the end of the storage, chitosan coating significantly reduced all microbiological population counts, except lactic acid bacteria; while higher reduction was observed with chitosan coating combined with a heat shock treatment. A significant delay at the beginning of the exponential phase was observed for all the bacterial populations analyzed. On the other hand, CMC coating, with and without a previous thermal treatment, did not exert any antibacterial effect. Excellent agreement was found between experimental microbial counts and predicted values obtained from Gompertz and logistic models. Kinetic modeling was found to be valuable for prediction of microbiological shelf life of broccoli during storage. Results showed that the application of chitosan coating effectively maintained microbiological quality and extended shelf life of minimally processed broccoli. According to these results, the use of the edible chitosan coating alone or in combination with a heat mild shock appear to be a viable alternative for controlling microbiological growth and sensory attributes in minimally processed broccoli. The continuous consumer interest in high quality and food safety, combined with environmental concern has induced to the development and study of edible coatings that avoid the use of synthetic materials. The edible coatings, formed from generally recognized as safe materials, have the potential to reduce weight loss, respiration rate, and

  20. Simulation analysis on dynamic performance of a combined solar/air dual source heat pump water heater

    International Nuclear Information System (INIS)

    Deng, Weishi; Yu, Jianlin

    2016-01-01

    Highlights: • A modified direct expansion solar-assisted heat pump water heater is investigated. • An additional air source evaporator is used in parallel way in the M-DX-SHPWH system. • The M-DX-SHPWH system displays a higher performance at the low solar radiation. • Effects of solar radiation and air temperature on the performance are discussed. - Abstract: This paper investigated a combined solar/air dual source heat pump water heater system for domestic water heating application. In the dual source system, an additional air source evaporator is introduced in parallel way based on a conventional direct expansion solar-assisted heat pump water heaters (DX-SHPWH) system, which can improve the performance of the DX-SHPWH system at a low solar radiation. In the present study, a dynamic mathematical model based on zoned lump parameter approach is developed to simulate the performance of the system (i.e. a modified DX-SHPWH (M-DX-SHPWH) system). Using the model, the performance of M-DX-SHPWH system is evaluated and then compared with that of the conventional DX-SHPWH system. The simulation results show the M-DX-SHPWH system has a better performance than that of the conventional DX-SHPWH system. At a low solar radiation of 100 W/m"2, the heating time of the M-DX-SHPWH decreases by 19.8% compared to the DX-SHPWH when water temperature reaches 55 °C. Meanwhile, the COP on average increases by 14.1%. In addition, the refrigerant mass flow rate distribution in the air source evaporator and the solar collector of the system, the allocation between the air source evaporator and the solar collector areas and effects of solar radiation and ambient air temperature on the system performance are discussed.

  1. Analysis of combined heat and mass transfer of water- Vapor in a ...

    African Journals Online (AJOL)

    In this paper, the combined heat and mass transfer of water-vapor into a cylindrical zeolite adsorber has been numerically simulated The twodimensional heat and mass transfer equations are numerically solved using gPROMS program - a general Process Modeling System {lJ program, inserting the proper initial and ...

  2. Analysis of combined heat and mass transfer of water-vapor in a ...

    African Journals Online (AJOL)

    Jn this paper, the combined heat and mass transfer of water-vapor into a cylindrical zeolite adsorber has been numerically simulated The twodimensional heat and mass transfer equations are numerically solved using gPROMS program - a general Process Modeling System [J] program, inserting the proper initial and ...

  3. Exergy costing for energy saving in combined heating and cooling applications

    International Nuclear Information System (INIS)

    Nguyen, Chan; Veje, Christian T.; Willatzen, Morten; Andersen, Peer

    2014-01-01

    Highlights: • We investigate the basis for cost apportioning of simultaneous heating and cooling. • Two thermoeconomic methods based on energy and exergy costing is demonstrated. • The unit cost of heating and cooling for a heat pump system is found and compared. • Energy costing may obstruct efficient use of energy. • Exergy costing provides the most rational cost apportioning for energy saving. - Abstract: The aim of this study is to provide a price model that motivates energy saving for a combined district heating and cooling system. A novel analysis using two thermoeconomic methods for apportioning the costs to heating and cooling provided simultaneously by an ammonia heat pump is demonstrated. In the first method, referred to as energy costing, a conventional thermoeconomic analysis is used. Here the ammonia heat pump is subject to a thermodynamic analysis with mass and energy balance equations. In the second method referred to as exergy costing, an exergy based economic analysis is used, where exergy balance equations are used in conjunction with mass and energy balance equations. In both costing methods the thermodynamic analysis is followed by an economic analysis which includes investment and operating costs. For both methods the unit costs of heating and cooling are found and compared. The analysis shows that the two methods yield significantly different results. Rather surprisingly, it is demonstrated that the exergy costing method results in about three times higher unit cost for heating than for cooling as opposed to equal unit costs when using the energy method. Further the exergy-based cost for heating changes considerably with the heating temperature while that of cooling is much less affected

  4. Combined heat transfer and kinetic models to predict cooking loss during heat treatment of beef meat.

    Science.gov (United States)

    Kondjoyan, Alain; Oillic, Samuel; Portanguen, Stéphane; Gros, Jean-Bernard

    2013-10-01

    A heat transfer model was used to simulate the temperature in 3 dimensions inside the meat. This model was combined with a first-order kinetic models to predict cooking losses. Identification of the parameters of the kinetic models and first validations were performed in a water bath. Afterwards, the performance of the combined model was determined in a fan-assisted oven under different air/steam conditions. Accurate knowledge of the heat transfer coefficient values and consideration of the retraction of the meat pieces are needed for the prediction of meat temperature. This is important since the temperature at the center of the product is often used to determine the cooking time. The combined model was also able to predict cooking losses from meat pieces of different sizes and subjected to different air/steam conditions. It was found that under the studied conditions, most of the water loss comes from the juice expelled by protein denaturation and contraction and not from evaporation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Waste-heat boiler application for the Vresova combined cycle plant

    Energy Technology Data Exchange (ETDEWEB)

    Vicek, Z. [Energoprojekt Praha, Prague (Czechoslovakia)

    1995-12-01

    This report describes a project proposal and implementation of two combined-cycle units of the Vresova Fuel Complex (PKV) with 2 x 200 MWe and heat supply. Participation of ENERGOPROJECT Praha a.s., in this project.

  6. Thermal performance measurements on ultimate heat sinks--cooling ponds

    International Nuclear Information System (INIS)

    Hadlock, R.K.; Abbey, O.B.

    1977-12-01

    The primary objective of the studies described is to obtain the requisite data, with respect to modeling requirements, to characterize thermal performance of heat sinks for nuclear facilities existing at elevated water temperatures in result of experiencing a genuinely large heat load and responding to meteorological influence. The data should reflect thermal performance for combinations leading to worst-case meteorological influence. A geothermal water retention basin has been chosen as the site for the first measurement program and data have been obtained in the first of several experiments scheduled to be performed there. These data illustrate the thermal and water budgets during episodes of cooling from an initially high pond water bulk temperature. Monitoring proceeded while the pond experienced only meteorological and seepage influence. The data are discussed and are presented as a data volume which may be used for calculation purposes. Suggestions for future measurement programs are stated with the intent to maintain and improve relevance to nuclear ultimate heat sinks while continuing to examine the performance of the analog geothermal pond. It is further suggested that the geothermal pond, with some modification, may be a suitable site for spray pond measurements

  7. Optimal Operation of Network-Connected Combined Heat and Powers for Customer Profit Maximization

    Directory of Open Access Journals (Sweden)

    Da Xie

    2016-06-01

    Full Text Available Network-connected combined heat and powers (CHPs, owned by a community, can export surplus heat and electricity to corresponding heat and electric networks after community loads are satisfied. This paper proposes a new optimization model for network-connected CHP operation. Both CHPs’ overall efficiency and heat to electricity ratio (HTER are assumed to vary with loading levels. Based on different energy flow scenarios where heat and electricity are exported to the network from the community or imported, four profit models are established accordingly. They reflect the different relationships between CHP energy supply and community load demand across time. A discrete optimization model is then developed to maximize the profit for the community. The models are derived from the intervals determined by the daily operation modes of CHP and real-time buying and selling prices of heat, electricity and natural gas. By demonstrating the proposed models on a 1 MW network-connected CHP, results show that the community profits are maximized in energy markets. Thus, the proposed optimization approach can help customers to devise optimal CHP operating strategies for maximizing benefits.

  8. City/industry/utility partnership leads to innovative combined heat and power project

    Energy Technology Data Exchange (ETDEWEB)

    Savage, J. [Savage and Associates, Quesnel, BC (Canada)

    2010-07-01

    This presentation discussed a combined heat and power (CHP) project that was launched in Quesnel, British Columbia. The CHP is being developed in phases in which new components will enter the system, providing added benefits. Hot oil from a sawmill bioenergy system will be used to heat lumber kilns, generate electricity at an Organic Rankine Cycle co-generation plant, and heat water for a District Energy Loop (DEL) to heat up to 22 existing buildings in the city as well as sawmill and planer buildings. The DEL piping would comprise a 5 kilometre loop. The energy would come from recovered sawmill space heating, recovered stack energy, and additional biomass energy. All of the district heating and 41 per cent of the power would be from heat recovered from the existing industrial operation. This bio-economy vision ultimately involves incorporating a biogas digester into the system to process food, regional organic waste, and pulp mill residuals, relying on bio-solids and heat from the mill. The fertilizer from the digester would then be used in a biomass plantation, which would provide materials to industry for many products, including bio-refining. This project evolved in response to concerns about the ecological effects and long-term economics of aggressive utilization of forest biomass. 15 figs.

  9. Thermodynamic performance analysis of a combined power cycle using low grade heat source and LNG cold energy

    International Nuclear Information System (INIS)

    Kim, Kyoung Hoon; Kim, Kyung Chun

    2014-01-01

    Thermodynamic analysis of a combined cycle using a low grade heat source and LNG cold energy was carried out. The combined cycle consisted of an ammonia–water Rankine cycle with and without regeneration and a LNG Rankine cycle. A parametric study was conducted to examine the effects of the key parameters, such as ammonia mass fraction, turbine inlet pressure, condensation temperature. The effects of the ammonia mass fraction on the temperature distributions of the hot and cold streams in heat exchangers were also investigated. The characteristic diagram of the exergy efficiency and heat transfer capability was proposed to consider the system performance and expenditure of the heat exchangers simultaneously. The simulation showed that the system performance is influenced significantly by the parameters with the ammonia mass fraction having largest effect. The net work output of the ammonia–water cycle may have a peak value or increase monotonically with increasing ammonia mass fraction, which depends on turbine inlet pressure or condensation temperature. The exergy efficiency may decrease or increase or have a peak value with turbine inlet pressure depending on the ammonia mass fraction. - Highlights: • Thermodynamic analysis was performed for a combined cycle utilizing LNG cold energy. • Ammonia–water Rankine cycle and LNG Rankine cycle was combined. • A parametric study was conducted to examine the effects of the key parameters. • Characteristics of the exergy efficiency and heat transfer capability were proposed. • The system performance was influenced significantly by the ammonia mass fraction

  10. Effects of combination of magnesium and zinc oxide nanoparticles and heat on Escherichia coli and Staphylococcus aureus bacteria in milk

    Directory of Open Access Journals (Sweden)

    M. Kimiaee Sadr

    2016-01-01

    Full Text Available Objective: The objective of this study was to investigate the antibacterial activities of combination of MgO and ZnO nanoparticles in the presence of heat against Escherichia coli and Staphylococcus aureus. Materials and Methods:Bacteria were grown on either agar or broth media followed by the addition of ZnO and MgO nanoparticles. Then the combined effect of ZnO and MgO nanoparticles was investigated.  Furthermore, the media containing nanoparticles were treated with mild heat and their synergistic antibacterial activity was investigated against E. coli and S. aureus in milk. Results: The data showed that the nanoparticles used in this study had no effect on the bacteria in the agar medium. However, the results showed that ZnO and MgO nanoparticles resulted in a significant decrease in the number of E. coli (P

  11. Combined coal gasification and Fe{sub 3}O{sub 4}-reduction using high-temperature solar process heat

    Energy Technology Data Exchange (ETDEWEB)

    Tamaura, Y [Tokyo Inst. of Technology, Tokyo (Japan); Ehrensberger, K; Steinfeld, A [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The coal/Fe{sub 3}O{sub 4} system was experimentally studied at PSI solar furnace. The reactants were directly exposed to a solar flux irradiation of 3,000 suns (1 sun = 1 kW/m{sup 2}). The combined gasification of coal and reduction of Fe{sub 2}O{sub 3} proceeded rapidly after only one second exposure, suggesting an efficient heat transfer and chemical conversion by direct solar energy absorption at the reaction site. The proposed solar thermochemical process offers the possibility of converting coal to a cleaner fluid fuel with a solar-upgraded calorific value. (author) 2 figs., 8 refs.

  12. Long-term optimization case studies for combined heat and power system

    Directory of Open Access Journals (Sweden)

    Polyzakis Apostolis L.

    2009-01-01

    Full Text Available In the next years distributed poly-generation systems are expected to play an increasingly important role in the electricity infrastructure and market. The successful spread of small-scale generation either connected to the distribution network or on the customer side of the meter depends on diverse issues, such as the possibilities of technical implementation, resource availability, environmental aspects, and regulation and market conditions. The aim of this approach is to develop an economic and parametric analysis of a distributed generation system based on gas turbines able to satisfy the energy demand of a typical hotel complex. Here, the economic performance of six cases combining different designs and regimes of operation is shown. The software Turbomatch, the gas turbine performance code of Cranfield University, was used to simulate the off-design performance of the engines in different ambient and load conditions. A clear distinction between cases running at full load and following the load could be observed in the results. Full load regime can give a shorter return on the investment then following the load. In spite combined heat and power systems being currently not economically attractive, this scenario may change in future due to environmental regulations and unavailability of low price fuel for large centralized power stations. Combined heat and power has a significant potential although it requires favorable legislative and fair energy market conditions to successfully increase its share in the power generation market.

  13. Economic evaluation of biogas and natural gas co-firing in gas turbine combined heat and power systems

    International Nuclear Information System (INIS)

    Kang, Jun Young; Kang, Do Won; Kim, Tong Seop; Hur, Kwang Beom

    2014-01-01

    This study investigated the economics of co-firing biogas and natural gas within a small gas turbine combined heat and power (CHP) plant. The thermodynamic performance of the CHP plant was calculated with varying gas mixing ratios, forming the basis for the economic analysis. A cost balance equation was used to calculate the costs of electricity and heat. The methodology was validated, and parametric analyses were used to investigate the influence of gas mixing ratio and heat sales ratio on the costs of electricity and heat. The cost of electricity generation from the CHP plant was compared to that of a central combined cycle power plant, and an economical gas mixing ratio range were suggested for various heat sales ratios. It was revealed that the effect of the heat sales ratio on the cost of electricity becomes greater as the proportion of natural gas is increased. It was also demonstrated that the economic return from the installation of CHP systems is substantially affected by the gas mixing ratio and heat sales ratio. Sensitivity analysis showed that influence of economic factors on the CHP plant is greater when a higher proportion of natural gas is used. - Highlights: • An appropriate method to calculate the costs of electricity (COE) and heat (COH) was established. • Both COE and COH increase with increasing natural gas mixing ratio and decreasing heat sales ratio. • The effect of the heat sales ratio on the COE becomes greater as the mixing ratio increases. • The payback period is considerably dependent on the mixing ratio and heat sales ratio

  14. Carbon, Water and Heat Fluxes Comparison between Two Subtropical Mangroves Sites, Southeastern China

    Science.gov (United States)

    Liu, F.; Lin, G., Sr.; Lu, W.; Chen, H.

    2014-12-01

    Due to the numerous ecological services provided by mangroves and its vital ecological role, the monitor of mangrove ecosystem in China receives a growing concern. We deployed eddy covariance system and meteorological instrument to continuously monitor the exchange of CO2 flux, water vapor, heat flux and meteorological factors of mangrove ecosystem on Guangdong and Fujian province in 2012, namely GDGQ and FJYX. The major species of two sites were similar, and by 2012 were on average 2.8~3.3 m in height. Climatically, temperature, net radiation and rainfall have significant seasonal difference, all reaching peak values during the summer wet season. Based on the results available, two sites were strong carbon sink in annual scale. The cumulative NEP in GDGQ (667.92 g C m-2 year-1) was lower than that in FJYX (848.31 g C m-2 year-1), but respiration (Rd) was opposite, 1433.80 g C m-2 year-1 for GDGQ and 1345.13 g C m-2 year-1 for FJYX. Tidal inundation decreased nighttime Rd by ~0.82 μ mol m-2 s-1 in GDGQ and ~0.99 μ mol m-2 s-1 in FJYX. The diurnal patterns of sensible (Hs) and latent heat fluxes (LE) of two sites were both single peak, and peak values both occurred at 12:00~14:00. Hs of GDGQ was higher than FJYX during nighttime and lower in daytime, but LE of GDGQ was lower than FJYX during nighttime. Evapotranspiration (ET) of two sites presented similar seasonal pattern, reaching highest value in July and lowest value in January. ET of whole year were 892.66 mm and 1051.76mm for GDGQ and FJYX. Daily WUE was strong negatively correlated to salinity in in FJYX, but the pattern of GDGQ was less distinct. Due to its high salinity stress and long-time inundation, water use efficiency (WUE) of GDGQ was higher than FJYX in all months. Soil heat flux (G) was quite small when compared to other heat flux, but both had obvious diurnal pattern in two sites. G was positively correlated to air temperature and G variation range of GDGQ (-8.68 ~5.51 w m-2) was greater than

  15. Robust Management of Combined Heat and Power Systems via Linear Decision Rules

    DEFF Research Database (Denmark)

    Zugno, Marco; Morales González, Juan Miguel; Madsen, Henrik

    2014-01-01

    The heat and power outputs of Combined Heat and Power (CHP) units are jointly constrained. Hence, the optimal management of systems including CHP units is a multicommodity optimization problem. Problems of this type are stochastic, owing to the uncertainty inherent both in the demand for heat and...... linear decision rules to guarantee both tractability and a correct representation of the dynamic aspects of the problem. Numerical results from an illustrative example confirm the value of the proposed approach....

  16. ComfortPower. Design, construction and evaluation of a combined fuel-cell and heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Silversand, Fredrik (Catator AB, Lund (Sweden))

    2010-12-15

    Catator AB has constructed, commissioned and evaluated a combined fuel-cell and heat-pump system (ComfortPower). The basic idea behind the project was to demonstrate the possibility to achieve ultrahigh thermal efficiencies when combining fuel-cell technologies and heat pumps. Moreover, the system should provide a great flexibility with respect to the fuel mix and should in addition to heat provide surplus electricity and cooling. The system was built on a HT-PEM platform (high temperature polymer electrolyte fuel cell from Serenergy a/s), which was operated by Catators proprietary Optiformer technology. The power generator was combined with a heat pump module (F1145-5, 230 V), supplied by Nibe. The system was packaged into a cabinet (1.65 x 0.6 x 0.6 m) comprising the power module, the heat pump, all necessary balance-of-plant components and the control system. The power output from the fuel-cell system was around 1.35 kW, which enabled operation of the heat pump compressor. By utilizing surplus heat energy from the fuel cell it was possible to achieve a favourable operation point in the heat pump system, resulting in a high overall COP (coefficient of performance). The heat output from the system was as high as 10 kW whereas 6 kW cooling could be provided. The thermal efficiencies measured in experiments were normally around 200%, calculated on the lower heating value of the fuel. A number of fuels have been investigated in the fuel cell system, including both gaseous (natural gas/LPG) and liquid fuels (alcohols and kerosene). Indeed, the system has a wide fuel flexibility, which opens up for a variety of applications in campus villages and buildings. This study has demonstrated the possibility to reduce the carbon dioxide footprint by a factor of 2 over conventional boilers in heating applications. In addition the unit can be operated on a variety of fuels and can produce cooling and electricity in addition to heat. A fully working system has been designed

  17. Heat recovery networks synthesis of large-scale industrial sites: Heat load distribution problem with virtual process subsystems

    International Nuclear Information System (INIS)

    Pouransari, Nasibeh; Maréchal, Francois

    2015-01-01

    Highlights: • Synthesizing industrial size heat recovery network with match reduction approach. • Targeting TSI with minimum exchange between process subsystems. • Generating a feasible close-to-optimum network. • Reducing tremendously the HLD computational time and complexity. • Generating realistic network with respect to the plant layout. - Abstract: This paper presents a targeting strategy to design a heat recovery network for an industrial plant by dividing the system into subsystems while considering the heat transfer opportunities between them. The methodology is based on a sequential approach. The heat recovery opportunity between process units and the optimal flow rates of utilities are first identified using a Mixed Integer Linear Programming (MILP) model. The site is then divided into a number of subsystems where the overall interaction is resumed by a pair of virtual hot and cold stream per subsystem which is reconstructed by solving the heat cascade inside each subsystem. The Heat Load Distribution (HLD) problem is then solved between those packed subsystems in a sequential procedure where each time one of the subsystems is unpacked by switching from the virtual stream pair back into the original ones. The main advantages are to minimize the number of connections between process subsystems, to alleviate the computational complexity of the HLD problem and to generate a feasible network which is compatible with the minimum energy consumption objective. The application of the proposed methodology is illustrated through a number of case studies, discussed and compared with the relevant results from the literature

  18. Study of a molten carbonate fuel cell combined heat, hydrogen and power system: Energy analysis

    International Nuclear Information System (INIS)

    Agll, Abdulhakim Amer A.; Hamad, Yousif M.; Hamad, Tarek A.; Thomas, Mathew; Bapat, Sushrut; Martin, Kevin B.; Sheffield, John W.

    2013-01-01

    Countries around the world are trying to use alternative fuels and renewable energy to reduce the energy consumption and greenhouse gas emissions. Biogas contains methane is considered a potential source of clean renewable energy. This paper discusses the design of a combined heat, hydrogen and power system, which generated by methane with use of Fuelcell, for the campus of Missouri University of Science and Technology located in Rolla, Missouri, USA. An energy flow and resource availability study was performed to identify sustainable type and source of feedstock needed to run the Fuelcell at its maximum capacity. FuelCell Energy's DFC1500 unit (a molten carbonate Fuelcell) was selected as the Fuelcell for the tri-generation (heat, hydrogen and electric power) system. This tri-generation system provides electric power to the campus, thermal energy for heating the anaerobic digester, and hydrogen for transportation, backup power and other applications on the campus. In conclusion, the combined heat, hydrogen and power system reduces fossil fuel usage, and greenhouse gas emissions at the university campus. -- Highlights: • Combined heat, hydrogen and power (CHHP) using a molten carbonate fuel cell. • Energy saving and alternative fuel of the products are determined. • Energy saving is increased when CHHP technology is implemented. • CHHP system reduces the greenhouse gas emissions and fuel consumption

  19. Pre-HEAT: submillimeter site testing and astronomical spectra from Dome A, Antarctica

    Science.gov (United States)

    Kulesa, C. A.; Walker, C. K.; Schein, M.; Golish, D.; Tothill, N.; Siegel, P.; Weinreb, S.; Jones, G.; Bardin, J.; Jacobs, K.; Martin, C. L.; Storey, J.; Ashley, M.; Lawrence, J.; Luong-Van, D.; Everett, J.; Wang, L.; Feng, L.; Zhu, Z.; Yan, J.; Yang, J.; Zhang, X.-G.; Cui, X.; Yuan, X.; Hu, J.; Xu, Z.; Jiang, Z.; Yang, H.; Li, Y.; Sun, B.; Qin, W.; Shang, Z.

    2008-07-01

    Pre-HEAT is a 20 cm aperture submillimeter-wave telescope with a 660 GHz (450 micron) Schottky diode heterodyne receiver and digital FFT spectrometer for the Plateau Observatory (PLATO) developed by the University of New South Wales. In January 2008 it was deployed to Dome A, the summit of the Antarctic plateau, as part of a scientific traverse led by the Polar Research Institute of China and the Chinese Academy of Sciences. Dome A may be one of the best sites in the world for ground based Terahertz astronomy, based on the exceptionally cold, dry and stable conditions which prevail there. Pre-HEAT is measuring the 450 micron sky opacity at Dome A and mapping the Galactic Plane in the 13CO J=6-5 line, constituting the first submillimeter measurements from Dome A. It is field-testing many of the key technologies for its namesake -- a successor mission called HEAT: the High Elevation Antarctic Terahertz telescope. Exciting prospects for submillimeter astronomy from Dome A and the status of Pre-HEAT will be presented.

  20. Industrial Application of Topology Optimization for Combined Conductive and Convective Heat Transfer Problems

    DEFF Research Database (Denmark)

    Zhou, Mingdong; Alexandersen, Joe; Sigmund, Ole

    2016-01-01

    This paper presents an industrial application of topology optimization for combined conductive and convective heat transfer problems. The solution is based on a synergy of computer aided design and engineering software tools from Dassault Systemes. The considered physical problem of steady......-state heat transfer under convection is simulated using SIMULIA-Abaqus. A corresponding topology optimization feature is provided by SIMULIA-Tosca. By following a standard workflow of design optimization, the proposed solution is able to accommodate practical design scenarios and results in efficient...

  1. Optimization of operation for combined heat and power plants - CHP plants - with heat accumulators using a MILP formulation

    Energy Technology Data Exchange (ETDEWEB)

    Grue, Jeppe; Bach, Inger [Aalborg Univ. (Denmark). Inst. of Energy Technology]. E-mails: jeg@iet.auc.dk; ib@iet.auc.dk

    2000-07-01

    The power generation system in Denmark is extensively based on small combined heat and power plants (CHP plants), producing both electricity and district heating. This project deals with smaller plants spread throughout the country. Often a heat accumulator is used to enable electricity production, even when the heat demand is low. This system forms a very complex problem, both for sizing, designing and operation of CHP plants. The objective of the work is the development of a tool for optimisation of the operation of CHP plants, and to even considering the design of the plant. The problem is formulated as a MILP-problem. An actual case is being tested, involving CHP producing units to cover the demand. The results from this project show that it is of major importance to consider the operation of the plant in detail already in the design phase. It is of major importance to consider the optimisation of the plant operation, even at the design stage, as it may cause the contribution margin to rise significantly, if the plant is designed on the basis of a de-tailed knowledge of the expected operation. (author)

  2. Combined natural convection and radiation in a volumetrically heated fluid layer

    International Nuclear Information System (INIS)

    Chawla, T.C.; Chan, S.H.; Cheung, F.B.; Cho, D.H.

    1980-01-01

    The effect of radiation in combination with turbulent natural convection on the rates of heat transfer in volumetrically heated fluid layers characterized by high temperatures has been considered in this study. It is demonstrated that even at high Rayleigh numbers the radiation mode is as effective as the turbulent natural convection mode in removing the heat from the upper surface of the molten pools with adiabatic lower boundary. As a result of this improved heat transfer, it is shown that considerably thicker molten pools with internal heat generation can be supported without boiling inception. The total Nusselt number at a moderate but fixed value of conduction-radiation parameter, can be represented as a function of Rayleigh number in a simple power-law form. As a consequence of this relationship it is shown that maximum nonboiling pool thicknesses vary approximately inversely as the 0.9% power of internal heat generation rate. A comparison between exact analysis using the integral formulation of radiation flux and Rosseland approximation shows that the latter approximation bears out very adequately for optically thick pools with conduction-radiation parameters greater than or equal to 0.4 inspite of the fact that individual components of Nusselt number due to radiation and convection, respectively, are grossly in error. These errors in component heat fluxes are compensating due to the total heat balance constraint. However, the comparison between Rosseland approximation and exact formulation gets poorer as the value of conduction-radiation parameters decreases. This increase in error is principally incurred due to the error in estimating wall temperature differences

  3. Combined natural convection and radiation in a volumetrically heated fluid layer

    International Nuclear Information System (INIS)

    Chawla, T.C.; Chan, S.H.; Cheung, F.B.; Cho, D.H.

    1980-01-01

    The effect of radiation in combining with turbulent natural convection on the rates of heat transfer in volumetrically heated fluid layers characterized by high temperatures has been considered in this study. It is demonstrated that even at high Rayleigh numbers the radiation mode is as effective as the turbulent natural convection mode in removing the heat from the upper surface of molten pools with adiabatic lower boundary. As a result of this improved heat transfer, it is shown that considerably thicker molten pools with internal heat generation can be supported without boiling inception. The total Nusselt number at a moderate but fixed value of conduction-radiation parameter, can be represented as a function of Rayleigh number in a simple power-law form. As a consequence of this relationship it is shown that maximum nonboiling pool thicknesses vary approximately inversely as the 0.9 power of internal heat generation rate. A comparison between exact analysis using the integral formulation of radiation flux and Rosseland approximateion shows that the latter approximation bears out very adequately for optically thick pools with conduction-radiation parameter > or approx. =0.4 inspite of the fact that individual components of Nusselt number due to radiation and convection, respectively, are grossly in error. These errors in component heat fluxes are compensating due to the total heat balance constraint. However, the comparison between Rosseland approximation and exact formulation gets poorer as the value of conduction-radiation parameter decreases. This increase in error is principally incurred due to the error in estimating wall temperature differences

  4. Diffusion of combined heat and power in Dutch greenhouses : A case study

    NARCIS (Netherlands)

    Dijkema, G.P.J.; Kasmire, J.; Van der Veen, R.A.C.

    2012-01-01

    This report presents the case study of the rapid diffusion of combined heat and power (CHP) units in the Dutch greenhouse horticulture in the period 2003-2009. The aim of the case study is to find explanations for this particular transition, and to generalize on the nature of technology diffusion

  5. Accelerating the energy policy turnaround with combined heat and power units; Mit Blockheizkraftwerken die Energiewende rund machen

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Joerg; Geiler, Nikolaus [Klimabuendnis Freiburg, Freiburg im Breisgau (Germany)

    2013-03-15

    No other type of decentralized power plants transforms natural gas to electric power so efficiently as a combined heat and power unit. In the long term, the climate-friendly effect using renewable hydrogen or renewably generated 'natural gas' even could be increased. Thus, combined heat and power units are ideal to achieve the national climate change objectives. Despite their advantages, the implementation of combined heat and power units advances only sluggishly.

  6. Exergoeconomic performance optimization of an endoreversible intercooled regenerative Brayton combined heat and power plant coupled to variable-temperature heat reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bo; Chen, Lingen; Sun, Fengrui [College of Naval Architecture and Power, Naval University of Engineering, Wuhan 430033 (China)

    2012-07-01

    An endoreversible intercooled regenerative Brayton combined heat and power (CHP) plant model coupled to variable-temperature heat reservoirs is established. The exergoeconomic performance of the CHP plant is investigated using finite time thermodynamics. The analytical formulae about dimensionless profit rate and exergy efficiency of the CHP plant with the heat resistance losses in the hot-, cold- and consumer-side heat exchangers, the intercooler and the regenerator are deduced. By taking the maximum profit rate as the objective, the heat conductance allocation among the five heat exchangers and the choice of intercooling pressure ratio are optimized by numerical examples, the characteristic of the optimal dimensionless profit rate versus corresponding exergy efficiency is investigated. When the optimization is performed further with respect to the total pressure ratio, a double-maximum profit rate is obtained. The effects of the design parameters on the double-maximum dimensionless profit rate and corresponding exergy efficiency, optimal total pressure ratio and optimal intercooling pressure ratio are analyzed in detail, and it is found that there exist an optimal consumer-side temperature and an optimal thermal capacitance rate matching between the working fluid and the heat reservoir, respectively, corresponding to a thrice-maximum dimensionless profit rate.

  7. A new thermodynamic model for shaftwork targeting on total sites

    Energy Technology Data Exchange (ETDEWEB)

    Sorin, M.; Hammache, A. [CANMET Energy Technology Centre-Varennes, Quebec (Canada)

    2005-05-01

    The purpose of the paper is to introduce a targeting model based on a new thermodynamic insight on cogeneration in general and Rankine cycle in particular. The insight permits to express the ideal shaftwork of a cogeneration unit through the outlet heat load and the difference in Carnot factors between the heat source and heat sink for the given inlet temperature of the heat source. The deviation from the ideal shaftwork to the real one is assessed by using the traditionally turbine isentropic efficiency. Finally the new model allows targeting fuel consumption, cooling requirement and shaftwork production with high accuracy and visualizing then directly as special segments on the T-H diagram. A modified Site Utility Grand Composite Curve (SUGCC) diagram is proposed and compared to the original SUGCC. The shape of the right hand side of the diagram above site pinch is the same, however, below site pinch it is shifted to the left by an amount equal to shaftwork production below site pinch. Above site pinch VHP consumption is also corrected to account for shaftwork production above site pinch that is represented by segments rather than areas on the left hand side of the T-H diagram. (author)

  8. Profitability aspects of combined power/heat plants based on the example of a gas turbine; Wirtschaftlichkeitsbetrachtungen ueber KWK-Anlagen am Beispiel einer Gasturbine

    Energy Technology Data Exchange (ETDEWEB)

    Klimek, W. [Thyssengas GmbH, Duisburg (Germany)

    1998-04-01

    The efficiency of a combined power/heat plant is treated in an example relating to a gas turbine. An important prior condition for optimum planning of a combined power/heat plant is assessment of the current position in addition to a demand analysis. Constituting a vital planning instrument for the process are systematic annual continuous curves in respect of electricity and heat. Aided by a PC software program it is possible, on the basis of a few key figures, to establish whether a detailed study is able to bring about any economical solution. In addition, a primary-energy and emission balance-sheet is compiled illustrating the advantages to be gained from combined power/heat systems of relevance to the environment. A sensitivity analysis shows main influential factors exercised on the efficiency of the gas turbine project. As might be expected, the greatest influenc eon profitability comes from the electricity proceeds, the price of fuel and capital costs. Finally, different financing models for combined power/heat plants are discussed along with a price safeguarding method. (orig.) [Deutsch] Die Wirtschaftlichkeit einer KWK-Anlage wird am Beispiel einer Gasturbine erlaeutert. Wichtige Voraussetzung fuer die optimale Planung einer KWK-Anlage ist die Bestandsaufnahme mit Bedarfsanalyse. Ein entscheidendes Planungsinstrument stellen hierbei geordnete Jahresdauerlinien fuer Strom und Waerme dar. Mit Hilfe eines PC-Programms kann anhand weniger Eckdaten festgestellt werden, ob eine Detailbetrachtung zu einer wirtschaftlichen Loesung fuehren koennte. Zusaetzlich wird eine Primaerenergie- und Emissionsbilanz erstellt, die die umweltrelevanten Vorteile der Kraft-Waerme-Kopplung verdeutlicht. Eine Sensitivitaetsanalyse zeigt Haupteinflussfaktoren auf die Wirtschaftlichkeit des Gasturbinenprojektes. Die Stromgutschrift, der Brennstoffpreis und die Investitionskosten ueben erwartungsgemaess den groessten Einfluss auf die Wirtschaftlichkeit aus. Abschliessend werden

  9. Thermodynamic Analysis of a Ship Power Plant Operating with Waste Heat Recovery through Combined Heat and Power Production

    Directory of Open Access Journals (Sweden)

    Mirko Grljušić

    2014-11-01

    Full Text Available The goal of this research is to study a cogeneration plant for combined heat & power (CHP production that utilises the low-temperature waste energy in the power plant of a Suezmax-size oil tanker for all heating and electricity requirements during navigation. After considering various configurations, a standard propulsion engine operating at maximum efficiency and a CHP Plant with R245fa fluid using a supercritical organic Rankine cycle (ORC is selected. All the ship heat requirements can be covered by energy of organic fluid after expansion in the turbine, except feeder-booster heating. Hence, an additional quantity of working fluid may be heated using an after Heat Recovery Steam Generator (HRSG directed to the feeder-booster module. An analysis of the obtained results shows that the steam turbine plant does not yield significant fuel savings. However, a CHP plant with R245fa fluid using supercritical ORC meets all of the demands for electrical energy and heat while burning only a small amount of additional fuel in HRSG at the main engine off-design operation.

  10. Physiological and metabolic changes of purslane (Portulaca oleracea L. in response to drought, heat and combined stresses

    Directory of Open Access Journals (Sweden)

    Rui eJin

    2016-01-01

    Full Text Available Purslane (Portulaca oleracea L. is a fleshy herbaceous plant. So far, little information is available on the response of this plant to combined drought and heat stress. In this study, changes in physiological and metabolic levels were characterized after treatments with drought, heat and combined stresses. Both individual and combined stress treatments increased malondialdehyde (MDA, electrolyte leakage (EL, O2•− and activities of superoxide dismutase (SOD, peroxidase (POD, while declined chlorophyll content. No significant differences were found between control and treatments in leaf water content (LWC and catalase (CAT activity. Additionally, 37 metabolic compounds were detected in purslane. Through pathway analysis, 17 metabolites were directly involved in the glycolysis metabolic pathway. The present study indicated that combined drought and heat stress caused more serious damage in purslane than individual stress. To survive, purslane has a high capability to cope with environmental stress conditions through activation of physiological and metabolic pathways.

  11. Physiological and Metabolic Changes of Purslane (Portulaca oleracea L.) in Response to Drought, Heat, and Combined Stresses

    Science.gov (United States)

    Jin, Rui; Wang, Yanping; Liu, Ruijie; Gou, Junbo; Chan, Zhulong

    2016-01-01

    Purslane (Portulaca oleracea L.) is a fleshy herbaceous plant. So far, little information is available on the response of this plant to combined drought and heat stress. In this study, changes in physiological and metabolic levels were characterized after treatments with drought, heat and combined stresses. Both individual and combined stress treatments increased malondialdehyde (MDA), electrolyte leakage (EL), O2•− and activities of superoxide dismutase (SOD), peroxidase (POD), while declined chlorophyll content. No significant differences were found between control and treatments in leaf water content (LWC) and catalase (CAT) activity. Additionally, 37 metabolic compounds were detected in purslane. Through pathway analysis, 17 metabolites were directly involved in the glycolysis metabolic pathway. The present study indicated that combined drought and heat stress caused more serious damage in purslane than individual stress. To survive, purslane has a high capability to cope with environmental stress conditions through activation of physiological and metabolic pathways. PMID:26779204

  12. Combined role of heat and water stresses on wheat, maize and rice inter-annual variability and trend from 1980 to 2010.

    Science.gov (United States)

    Zampieri, M.; Ceglar, A., , Dr; Dentener, F., , Dr; van den Berg, M., , Dr; Toreti, A., , Dr

    2017-12-01

    Heat waves and drought are often considered the most damaging climatic stressors for wheat and maize. In this study, based on data derived from observations, we characterize and attribute the effects of these climate extremes on wheat and maize yield anomalies (at global and national scales) with respect to the mean trend from 1980 to 2010. Using a combination of up-to-date heat wave and drought indexes (i.e. the Heat Magnitude Day, HMD, and the Standardized Precipitation Evapotranspiration Index, SPEI), we have developed a composite indicator (i.e. the Combined Stress Index, CSI) that is able to capture the spatio-temporal characteristics of the underlying physical processes in the different agro-climatic regions of the world. At the global level, our diagnostic explains the 42% and the 50% of the inter-annual wheat and maize production variabilities, respectively. The relative importance of heat stress and drought in determining the yield anomalies depends on the region. Compared to maize, and in contrast to common perception, water excess affects wheat production more than drought in several countries. The index definition can be modified in order to quantify the role of combined heat and water stress events occurrence in determining the recorded yield trends as well. Climate change is increasingly limiting maize yields in several countries, especially in Europe and China. A comparable opposite signal, albeit less statistically significant, is found for the USA, which is the main world producer. As for rice, we provide a statistical evidence pointing out to the importance of considering the interactions with the horizontal surface waters fluxes carried out by the rivers. In fact, compared to wheat and maize, the CSI statistical skills in explaining rice production variability are quite reduced. This issue is particularly relevant in paddy fields and flooded lowlands where rice is mainly grown. Therefore, we have modified the procedure including a proxy for the

  13. An improved model of heat-induced hyperalgesia--repetitive phasic heat pain causing primary hyperalgesia to heat and secondary hyperalgesia to pinprick and light touch.

    Science.gov (United States)

    Jürgens, Tim P; Sawatzki, Alexander; Henrich, Florian; Magerl, Walter; May, Arne

    2014-01-01

    This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (-31%) and in particular of secondary hyperalgesia (-59%) as well as the magnitude of hyperalgesia (-59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input.

  14. An Improved Model of Heat-Induced Hyperalgesia—Repetitive Phasic Heat Pain Causing Primary Hyperalgesia to Heat and Secondary Hyperalgesia to Pinprick and Light Touch

    Science.gov (United States)

    Henrich, Florian; Magerl, Walter; May, Arne

    2014-01-01

    This study tested a modified experimental model of heat-induced hyperalgesia, which improves the efficacy to induce primary and secondary hyperalgesia and the efficacy-to-safety ratio reducing the risk of tissue damage seen in other heat pain models. Quantitative sensory testing was done in eighteen healthy volunteers before and after repetitive heat pain stimuli (60 stimuli of 48°C for 6 s) to assess the impact of repetitive heat on somatosensory function in conditioned skin (primary hyperalgesia area) and in adjacent skin (secondary hyperalgesia area) as compared to an unconditioned mirror image control site. Additionally, areas of flare and secondary hyperalgesia were mapped, and time course of hyperalgesia determined. After repetitive heat pain conditioning we found significant primary hyperalgesia to heat, and primary and secondary hyperalgesia to pinprick and to light touch (dynamic mechanical allodynia). Acetaminophen (800 mg) reduced pain to heat or pinpricks only marginally by 11% and 8%, respectively (n.s.), and had no effect on heat hyperalgesia. In contrast, the areas of flare (−31%) and in particular of secondary hyperalgesia (−59%) as well as the magnitude of hyperalgesia (−59%) were significantly reduced (all pheat pain induces significant peripheral sensitization (primary hyperalgesia to heat) and central sensitization (punctate hyperalgesia and dynamic mechanical allodynia). These findings are relevant to further studies using this model of experimental heat pain as it combines pronounced peripheral and central sensitization, which makes a convenient model for combined pharmacological testing of analgesia and anti-hyperalgesia mechanisms related to thermal and mechanical input. PMID:24911787

  15. Combined Heat and Power Systems for the Provision of Sustainable Energy from Biomass in Buildings

    Directory of Open Access Journals (Sweden)

    Ortwein Andreas

    2016-01-01

    Full Text Available Against the background of greenhouse gases causing climate change, combined heat and power (CHP systems fueled by biomass can efficiently supply energy with high flexibility. Such CHP systems will usually consist of one or more thermo-chemical conversion steps and at least one (the more or less separated electric power generation unit. Depending on the main products of the previous conversion steps (e.g. combustible gases or liquids, but also flue gases with sensible heat, different technologies are available for the final power conversion step. This includes steam cycles with steam turbines or engines and different working fluids (water, organic fluids, but also combustion based systems like gas turbines or gas engines. Further promising technologies include fuel cells with high electric efficiency. When integrating such CHP systems in buildings, there are different strategies, especially concerning electric power generation. While some concepts are focusing on base load production, others are regulated either by thermal or by electric power demand. The paper will give a systematic overview on the combination of thermo-chemical conversion of biomass and combined heat and power production technologies. The mentioned building integration strategies will be discussed, leading to conclusions for further research and development in that field.

  16. Calculations of combined radiation and convection heat transfer in rod bundles under emergency cooling conditions

    International Nuclear Information System (INIS)

    Sun, K.H.; Gonzalez-Santalo, J.M.; Tien, C.L.

    1976-01-01

    A model has been developed to calculate the heat transfer coefficients from the fuel rods to the steam-droplet mixture typical of Boiling Water Reactors under Emergency Core Cooling System (ECCS) operation conditions during a postulated loss-of-coolant accident. The model includes the heat transfer by convection to the vapor, the radiation from the surfaces to both the water droplets and the vapor, and the effects of droplet evaporation. The combined convection and radiation heat transfer coefficient can be evaluated with respect to the characteristic droplet size. Calculations of the heat transfer coefficient based on the droplet sizes obtained from the existing literature are consistent with those determined empirically from the Full-Length-Emergency-Cooling-Heat-Transfer (FLECHT) program. The present model can also be used to assess the effects of geometrical distortions (or deviations from nominal dimensions) on the heat transfer to the cooling medium in a rod bundle

  17. Minimum success criteria at SGTR combined with loss of secondary heat sink

    International Nuclear Information System (INIS)

    Parzer, I.; Petelin, S.

    1993-01-01

    A parametric analysis has been performed investigating minimum success criteria for the hypothetical Steam Generator Tube Rupture (SGTR) accident in a Pressurized Water Reactor (PWR) Nuclear Power Plant, combined with the total loss of secondary heat sink. The analyses have been performed by RELAP5/MOD2 and MOD3 computer codes using Krsko NPP input deck. The Krsko NPP is a 2-loop Westinghouse PWR, 640 MWe, located in Slovenia and operating from 1981. Two break sizes have been chosen for the SGTR event: 2 and 5 double-ended broken tubes have been assumed. Total loss of secondary heat sink has been assumed from the beginning of the calculation. The ways of cooling down the plant after the postulated accident have been investigated, including Bleed ampersand Feed through the primary system. The NPP Krsko Emergency Operating Procedures (EOP) have been verified for this case. Some suggestions have been made, how to improve FR-H.1 procedure (Loss of Secondary Heat Sink), to include some steps, which take into account also SGTR when it is combined with loss of secondary heat sink. Possible misinterpretations of E-0 procedure (Reactor Trip or Safety Injection) have been studied

  18. Combined generation of heat and power in central heating systems. Design rules for fitting in; Warmte/kracht in cv-systemen. Ontwerpregels voor inpassing

    Energy Technology Data Exchange (ETDEWEB)

    Wammes, J.A. [Emicon, Veenendaal (Netherlands); Tijs, J.C. [Tijs Energy Systems, Wijk bij Duurstede (Netherlands); Rulkens, L.J.W. [FD-Bouwzaken/LNV, Wageningen (Netherlands)

    1997-03-01

    Carefully thought-out integration, a technical and financial feasibility analysis and telemetry are the key concepts in the successful incorporation of total energy (combined heat and power) units into new or existing heating systems. Based on extensive experience with total energy plants, a number of consultants, engineers and suppliers operating in this broad field, on the initiative of the Central Netherlands Gas Company (Gasbedrijf Centraal Nederland) in Utrecht and the Gasunie energy company in Groningen, both in the Netherlands have published a manual entitled `Design rules for incorporating total energy units into central heating systems`. 2 figs., 3 ills., 5 refs. 3 figs., 4 ills., 1 tab.

  19. An effective heuristic for combined heat-and-power production planning with power ramp constraints

    International Nuclear Information System (INIS)

    Rong, Aiying; Lahdelma, Risto

    2007-01-01

    Combined heat-and-power (CHP) production is an increasingly important technology for its efficient utilization of primary-energy resources and for reducing CO 2 emissions. In the CHP plant, the generation of heat-and-power follows a joint characteristic, which makes the determination of both the marginal power production cost (MPPC) and the feasible operating region for the plant more complicated than for the power-only generation plant. Due to the interdependence between heat and power production, the power-ramp constraints, which limit how much the power production of a CHP plant may increase or decrease between two successive periods, may also imply constraints on the heat production. In this paper, we investigate the impact of power-ramp constraints on CHP production planning and develop a robust heuristic for dealing with the power-ramp constraints based on the solution to the problem with relaxed ramp-constraints (RRC). Numerical results based on realistic production models show that the heuristic can generate high-quality solutions efficiently. (author)

  20. Synergistic effect of heat and solar UV on DNA damage and water disinfection of E. coli and bacteriophage MS2.

    Science.gov (United States)

    Theitler, Dana Jennifer; Nasser, Abid; Gerchman, Yoram; Kribus, Abraham; Mamane, Hadas

    2012-12-01

    The response of a representative virus and indicator bacteria to heating, solar irradiation, or their combination, was investigated in a controlled solar simulator and under real sun conditions. Heating showed higher inactivation of Escherichia coli compared to the bacteriophage MS2. Heating combined with natural or simulated solar irradiation demonstrated a synergistic effect on the inactivation of E. coli, with up to 3-log difference for 50 °C and natural sun insolation of 2,000 kJ m(-2) (compared to the sum of the separate treatments). Similar synergistic effect was also evident when solar-UV induced DNA damage to E. coli was assessed using the endonuclease sensitive site assay (ESS). MS2 was found to be highly resistant to irradiation and heat, with a slightly synergistic effect observed only at 59 °C and natural sun insolation of 5,580 kJ m(-2). Heat treatment also hindered light-dependent recovery of E. coli making the treatment much more effective.

  1. Heat Islands

    Science.gov (United States)

    EPA's Heat Island Effect Site provides information on heat islands, their impacts, mitigation strategies, related research, a directory of heat island reduction initiatives in U.S. communities, and EPA's Heat Island Reduction Program.

  2. Using of biogas for combined cycle of heat and electricity in City Waste Water Treatment Plant in the city of Varna

    International Nuclear Information System (INIS)

    Stankov, N.; Ovcharov, A.; Nikolov, Ch.; Petrov, P.

    2013-01-01

    This report contains a good practice example of energy production by means of biogas utilization in a Bulgarian city waste water treatment plant in Varna city (WWTP). Sewage gas production is included in the waste water and deposits treatment technological scheme of the plant before their further disposal or utilization. Sewer gas is used to fuel a combined heat and power production module which is based on reciprocating gas engines technology. This article contains data from a real site and its purpose is to present the stages of the examined process as well as the technical, economical and environmental benefits from introduction of such technology in a city WWTP. (authors)

  3. Thermodynamic performance analysis and optimization of a solar-assisted combined cooling, heating and power system

    International Nuclear Information System (INIS)

    Wang, Jiangjiang; Lu, Yanchao; Yang, Ying; Mao, Tianzhi

    2016-01-01

    This study aims to present a thermodynamic performance analysis and to optimize the configurations of a hybrid combined cooling, heating and power (CCHP) system incorporating solar energy and natural gas. A basic natural gas CCHP system containing a power generation unit, a heat recovery system, an absorption cooling system and a storage tank is integrated with solar photovoltaic (PV) panels and/or a heat collector. Based on thermodynamic modeling, the thermodynamic performance, including energy and exergy efficiencies, under variable work conditions, such as electric load factor, solar irradiance and installation ratio, of the solar PV panels and heat collector is investigated and analyzed. The results of the energy supply side analysis indicate that the integration of solar PV into the CCHP system more efficiently improves the exergy efficiency, whereas the integration of a solar heat collector improves the energy efficiency. To match the building loads, the optimization method combined with the operation strategy is employed to optimize the system configurations to maximize the integrated benefits of energy and economic costs. The optimization results of demand–supply matching demonstrate that the integration of a solar heat collector achieves a better integrated performance than the solar PV integration in the specific case study. - Highlights: • Design a CCHP system integrated with solar PV and heat collector. • Present the energy and exergy analyses under variable work conditions. • Propose an optimization method of CCHP system for demand-supply matching.

  4. Combined Natural Convection and Radiation Heat Transfer of Various Absorbing-Emitting-Scattering Media in a Square Cavity

    Directory of Open Access Journals (Sweden)

    Xianglong Liu

    2014-01-01

    Full Text Available A numerical model is developed to simulate combined natural convection and radiation heat transfer of various anisotropic absorbing-emitting-scattering media in a 2D square cavity based on the discrete ordinate (DO method and Boussinesq assumption. The effects of Rayleigh number, optical thickness, scattering ratio, scattering phase function, and aspect ratio of square cavity on the behaviors of heat transfer are studied. The results show that the heat transfer of absorbing-emitting-scattering media is the combined results of radiation and natural convection, which depends on the physical properties and the aspect ratio of the cavity. When the natural convection becomes significant, the convection heat transfer is enhanced, and the distributions of NuR and Nuc along the walls are obviously distorted. As the optical thickness increases, NuR along the hot wall decreases. As the scattering ratio decreases, the NuR along the walls decreases. At the higher aspect ratio, the more intensive thermal radiation and natural convection are formed, which increase the radiation and convection heat fluxes. This paper provides the theoretical research for the optimal thermal design and practical operation of the high temperature industrial equipments.

  5. Combined Heat and Power in an open market

    International Nuclear Information System (INIS)

    Hawkins, A.

    1999-01-01

    The chances and risks for combined heat and power (CHP) installations presented by the future liberalisation of the electricity market in Switzerland are discussed. A summary of papers and speeches presented at a conference in Basle is presented. New developments in the electricity marketplace are looked at from the point of view of CHP unit manufacturers, the Federal Administration, energy policy makers and marketing experts. Examples are quoted concerning the situation in Germany and possible changes in power generation philosophy

  6. On site selection of thermoelectric power plants in polluted environment

    International Nuclear Information System (INIS)

    Gheorghe, A.V.

    1992-01-01

    This paper discusses the environmental impact of combined heat-power plants. The selection of the site of these plants depends on the spatial distribution law of pollutants and their chemical interaction with environment. The solutions of a diffusion equation describing a system of chemically interacting pollutants are given and discussed. The environmental impacts are described in terms of wind and atmosphere stability, effective and built stack height and the source distance parameters. The optimal constructive solutions are judged upon the concentrations of sulfur and nitrogen oxides at the ground level which must be kept under the maximum admissible limit. (author). 8 figs

  7. Research on suitable heating conditions during local PWHT. Pt. 1. Influence of heating conditions on temperature distribution

    International Nuclear Information System (INIS)

    Tanaka, Jinkichi; Horii, Yukihiko; Sato, Masanobu; Murakawa, Hidekazu; Wang Jianhua

    1999-01-01

    To improve weld joint properties a heat treatment so called post weld heat treatment (PWHT) is often implemented for steel weldment. Generally, the PWHT is conducted in a furnace at a factory. But in site welds such as the girth joint of pipe, a local PWHT is applied using electric heater and so on. In the local PWHT steep temperature gradient occurs depending on the heating condition and it leads to rise of the thermal stress in addition to the welding residual stress. However, heating condition is not always defined the same in some standards. Therefore, suitable heat conditions for the local PWHT were studied supposing the power plant and so on experimentally and theoretically. Temperature distribution and thermal strains under different heating conditions were measured during the local PWHT using carbon steel pipes of 340 mm in diameter and 53 mm in wall thickness. The temperature gradient, thermal strain were also analyzed using Finite Element Method (FEM) as axis-symmetric model. Further, the influences of pipe size and heat transfer coefficient on the temperature distribution were analyzed and suitable heating source widths for various pipe sizes were proposed from the viewpoint of temperature distribution. (orig.)

  8. Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

    International Nuclear Information System (INIS)

    Lythcke-Jørgensen, Christoffer; Haglind, Fredrik; Clausen, Lasse R.

    2014-01-01

    Highlights: • We model a system where lignocellulosic ethanol production is integrated with a combined heat and power (CHP) plant. • We conduct an exergy analysis for the ethanol production in six different system operation points. • Integrated operation, district heating (DH) production and low CHP loads all increase the exergy efficiency. • Separate operation has the largest negative impact on the exergy efficiency. • Operation is found to have a significant impact on the exergy efficiency of the ethanol production. - Abstract: Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible, and a gas boiler is used as back-up when integration is not possible. The system was evaluated according to six operation points that alternate on the following three different operation parameters: Load in the CHP unit, integrated versus separate operation, and inclusion of district heating production in the ethanol facility. The calculated standard exergy efficiency of the ethanol facility varied from 0.564 to 0.855, of which the highest was obtained for integrated operation at reduced CHP load and full district heating production in the ethanol facility, and the lowest for separate operation with zero district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the

  9. ANALYSIS OF THE IMPACT PROPERTIES OF THE COOLANT RECOVERY SYSTEM HEAT LOSSES OF COMBINED COMPRESSOR-POWER PLANT ON ITS CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Yusha V.L.

    2012-12-01

    Full Text Available The paper presents results of theoretical analysis of the effectiveness of an ideal thermodynamic cycle internal combustion engine combined with an external utilization of exhaust heat. The influence of the properties of the coolant circuit of utilization on its operational parameters and characteristics of the power plant.

  10. Combining different frequencies for electrical heating of saturated and unsaturated soil zones

    Energy Technology Data Exchange (ETDEWEB)

    Roland, U.; Holzer, F.; Kopinke, F.D. [Helmholtz Centre for Environmental Research - UFZ, Department of Environmental Engineering, Leipzig (Germany)

    2011-10-15

    In situ electrical heating of soil was studied applying different frequencies: low-frequency energy for resistive heating and radio-frequency energy for dielectric heating. Steep temperature gradients were observed for each heating mode under the condition of the coexistence of saturated and unsaturated soil zones. By combining the two heating modes, this undesired effect can be avoided, thus allowing efficient soil remediation especially when organic phases are accumulated at the capillary fringe. A parallel application of both frequencies was demonstrated as the most suitable method to reduce temperature gradients. By using electronic filters, both electric fields can be established by only one electrode array. This innovative concept is especially applicable for optimizing thermal remediation of light non-aqueous phase liquid contaminations or realizing thermally-enhanced electrokinetic removal of heavy metals. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Analysis of a combined heating and cooling system model under different operating strategies

    Science.gov (United States)

    Dzierzgowski, Mieczysław; Zwierzchowski, Ryszard

    2017-11-01

    The paper presents an analysis of a combined heating and cooling system model under different operating strategies. Cooling demand for air conditioning purposes has grown steadily in Poland since the early 1990s. The main clients are large office buildings and shopping malls in downtown locations. Increased demand for heat in the summer would mitigate a number of problems regarding District Heating System (DHS) operation at minimum power, affecting the average annual price of heat (in summertime the share of costs related to transport losses is a strong cost factor). In the paper, computer simulations were performed for different supply network water temperature, assuming as input, real changes in the parameters of the DHS (heat demand, flow rates, etc.). On the basis of calculations and taking into account investment costs of the Absorption Refrigeration System (ARS) and the Thermal Energy Storage (TES) system, an optimal capacity of the TES system was proposed to ensure smooth and efficient operation of the District Heating Plant (DHP). Application of ARS with the TES system in the DHS in question increases net profit by 19.4%, reducing the cooling price for consumers by 40%.

  12. Computer modeling of the combined effects of perfusion, electrical conductivity, and thermal conductivity on tissue heating patterns in radiofrequency tumor ablation.

    Science.gov (United States)

    Ahmed, Muneeb; Liu, Zhengjun; Humphries, Stanley; Goldberg, S Nahum

    2008-11-01

    To use an established computer simulation model of radiofrequency (RF) ablation to characterize the combined effects of varying perfusion, and electrical and thermal conductivity on RF heating. Two-compartment computer simulation of RF heating using 2-D and 3-D finite element analysis (ETherm) was performed in three phases (n = 88 matrices, 144 data points each). In each phase, RF application was systematically modeled on a clinically relevant template of application parameters (i.e., varying tumor and surrounding tissue perfusion: 0-5 kg/m(3)-s) for internally cooled 3 cm single and 2.5 cm cluster electrodes for tumor diameters ranging from 2-5 cm, and RF application times (6-20 min). In the first phase, outer thermal conductivity was changed to reflect three common clinical scenarios: soft tissue, fat, and ascites (0.5, 0.23, and 0.7 W/m- degrees C, respectively). In the second phase, electrical conductivity was changed to reflect different tumor electrical conductivities (0.5 and 4.0 S/m, representing soft tissue and adjuvant saline injection, respectively) and background electrical conductivity representing soft tissue, lung, and kidney (0.5, 0.1, and 3.3 S/m, respectively). In the third phase, the best and worst combinations of electrical and thermal conductivity characteristics were modeled in combination. Tissue heating patterns and the time required to heat the entire tumor +/-a 5 mm margin to >50 degrees C were assessed. Increasing background tissue thermal conductivity increases the time required to achieve a 50 degrees C isotherm for all tumor sizes and electrode types, but enabled ablation of a given tumor size at higher tissue perfusions. An inner thermal conductivity equivalent to soft tissue (0.5 W/m- degrees C) surrounded by fat (0.23 W/m- degrees C) permitted the greatest degree of tumor heating in the shortest time, while soft tissue surrounded by ascites (0.7 W/m- degrees C) took longer to achieve the 50 degrees C isotherm, and complete ablation

  13. Influence of heat pipe operating temperature on exhaust heat thermoelectric generation

    OpenAIRE

    Brito, F. P.; Martins, Jorge; Gonçalves, L. M.; Antunes, Nuno; Sousa, Diogo

    2013-01-01

    Increasingly stringent targets on energy efficiency and emissions, as well as growing vehicle electrification are making attractive the electric recovery of the energy normally wasted through the tailpipe of Internal Combustion Engines. Recent developments in thermoelectrics (TE) may soon make them a viable solution for such applications. This team has been exploring the potential of using TE modules in combination with variable conductance heat pipes for transferring the exhaust heat to ...

  14. Guide to Combined Heat and Power Systems for Boiler Owners and Operators

    Energy Technology Data Exchange (ETDEWEB)

    Oland, CB

    2004-08-19

    Combined heat and power (CHP) or cogeneration is the sequential production of two forms of useful energy from a single fuel source. In most CHP applications, chemical energy in fuel is converted to both mechanical and thermal energy. The mechanical energy is generally used to generate electricity, while the thermal energy or heat is used to produce steam, hot water, or hot air. Depending on the application, CHP is referred to by various names including Building Cooling, Heating, and Power (BCHP); Cooling, Heating, and Power for Buildings (CHPB); Combined Cooling, Heating, and Power (CCHP); Integrated Energy Systems (IES), or Distributed Energy Resources (DER). The principal technical advantage of a CHP system is its ability to extract more useful energy from fuel compared to traditional energy systems such as conventional power plants that only generate electricity and industrial boiler systems that only produce steam or hot water for process applications. By using fuel energy for both power and heat production, CHP systems can be very energy efficient and have the potential to produce electricity below the price charged by the local power provider. Another important incentive for applying cogeneration technology is to reduce or eliminate dependency on the electrical grid. For some industrial processes, the consequences of losing power for even a short period of time are unacceptable. The primary objective of the guide is to present information needed to evaluate the viability of cogeneration for new or existing industrial, commercial, and institutional (ICI) boiler installations and to make informed CHP equipment selection decisions. Information presented is meant to help boiler owners and operators understand the potential benefits derived from implementing a CHP project and recognize opportunities for successful application of cogeneration technology. Topics covered in the guide follow: (1) an overview of cogeneration technology with discussions about benefits

  15. Environmental flows and life cycle assessment of associated petroleum gas utilization via combined heat and power plants and heat boilers at oil fields

    International Nuclear Information System (INIS)

    Rajović, Vuk; Kiss, Ferenc; Maravić, Nikola; Bera, Oskar

    2016-01-01

    Highlights: • Environmental impact of associated petroleum gas flaring is discussed. • A modern trend of introducing cogeneration systems to the oil fields is presented. • Three alternative utilization options evaluated with life cycle assessment method. • Producing electricity and/or heat instead of flaring would reduce impacts. - Abstract: Flaring of associated petroleum gas is a major resource waste and causes considerable emissions of greenhouse gases and air pollutants. New environmental regulations are forcing oil industry to implement innovative and sustainable technologies in order to compete in growing energy market. A modern trend of introducing energy-effective cogeneration systems to the oil fields by replacing flaring and existing heat generation technologies powered by associated petroleum gas is discussed through material flow analysis and environmental impact assessment. The environmental assessment is based on the consequential life cycle assessment method and mainly primary data compiled directly from measurements on Serbian oil-fields or company-supplied information. The obtained results confirm that the utilization of associated petroleum gas via combined heat and power plants and heat boilers can provide a significant reduction in greenhouse gas emissions and resource depletion by displacing marginal production of heat and electricity. At the base case scenario, which assumes a 100% heat realization rate, the global warming potential of the combined heat and power plant and heat boiler scenarios were estimated at −4.94 and −0.54 kg CO_2_e_q Sm"−"3, whereas the cumulative fossil energy requirements of these scenarios were −48.7 and −2.1 MJ Sm"−"3, respectively. This is a significant reduction compared to the global warming potential (2.25 kg CO_2_e_q Sm"−"3) and cumulative fossil energy requirements (35.36 MJ Sm"−"3) of flaring. Nevertheless, sensitivity analyses have shown that life cycle assessment results are sensitive

  16. Interaction of the nucleation phenomena at adjacent sites in nucleate boiling

    International Nuclear Information System (INIS)

    Sultan, M.; Judd, R.L.

    1983-01-01

    The present investigation is an original study in nucleate pool boiling heat transfer combining theory and experiment in which water boiling at atmospheric pressure on a single copper surface at two different levels of heat and different levels of subcooling was studied. Cross spectral analysis of the signals generated by the emission of bubbles at adjacent nucleation sites was used to determine the relationship of the time elapsed between the start of bubble growth at the two neighbouring active sites with the distance separating them. The experimental results obtained indicated that for the lower level of heat flux at three different levels of subcooling, the elapsed time and distance were directly related. Theoretical predictions of a temperature disturbance propagating through the heating surface in the radial direction gave good agreement with the experimental findings, suggesting that this is the mechanism responsible for the activation of the surrounding nucleation sites

  17. Combined heat and power in industry and buildings

    International Nuclear Information System (INIS)

    Hinnells, Mark

    2008-01-01

    Combined heat and power (CHP) has huge potential to deliver energy savings and emissions reductions, and in many cases cost reductions too. But the market and regulatory framework is the key to delivering large-scale installations, and government has a poor record in delivering an appropriate framework. Technology is central to the future competitiveness and therefore uptake of CHP. It could lead to more efficient CHP electricity generation, permit the use of lower-carbon, renewable fuels, and enable the development of new products for new end uses, including micro-CHP and CHP in heat networks. The market for CHP has been difficult in the past few years, largely as a result of government market reforms. The UK's level of CHP skills, for installing current technologies and developing new ones, is low. The key issue is the creation of the right market framework to deliver CHP, and part of this is support for the energy services approach

  18. Involvement of ascorbate peroxidase and heat shock proteins on citrus tolerance to combined conditions of drought and high temperatures.

    Science.gov (United States)

    Balfagón, Damián; Zandalinas, Sara I; Baliño, Pablo; Muriach, María; Gómez-Cadenas, Aurelio

    2018-06-01

    Usually several environmental stresses occur in nature simultaneously causing a unique plant response. However, most of the studies until now have focused in individually-applied abiotic stress conditions. Carrizo citrange (Poncirus trifoliata L. Raf. X Citrus sinensis L. Osb.) and Cleopatra mandarin (Citrus reshni Hort. ex Tan.) are two citrus rootstocks with contrasting tolerance to drought and heat stress and have been used in this work as a model for the study of plant tolerance to the combination of drought and high temperatures. According to our results, leaf integrity and photosynthetic machinery are less affected in Carrizo than in Cleopatra under combined conditions of drought and heat stress. The pattern of accumulation of three proteins (APX, HSP101 and HSP17.6) involved in abiotic stress tolerance shows that they do not accumulate under water stress conditions individually applied. However, contents of APX and HSP101 are higher in Carrizo than in Cleopatra under stress combination whereas HSP17.6 has a similar behavior in both types of plants. This, together with a better stomatal control and a higher APX activity of Carrizo, contributes to the higher tolerance of Carrizo plants to the combination of stresses and point to it as a better rootstock than Cleopatra (traditionally used in areas with scare water supplies) under the predictable future climatic conditions with frequent periods of drought combined with high temperatures. This work also provides the basis for testing the tolerance of different citrus varieties grafted on these rootstocks and growing under different field conditions. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  19. Combining Fuzzy AHP with GIS and Decision Rules for Industrial Site Selection

    Directory of Open Access Journals (Sweden)

    Aissa Taibi

    2017-12-01

    Full Text Available This study combines Fuzzy Analytic Hierarchy Process (FAHP, Geographic Information System (GIS and Decision rules to provide decision makers with a ranking model for industrial sites in Algeria. A ranking of the suitable industrial areas is a crucial multi-criteria decision problem based on socio-economical and technical criteria as on environmental considerations. Fuzzy AHP is used for assessment of the candidate industrial sites by combining fuzzy set theory and analytic hierarchy process (AHP. The decision rule base serves as a filter that performs criteria pre-treatment involving a reduction of their numbers. GIS is used to overlay, generate criteria maps and for visualizing ranked zones on the map. The rank of a zone so obtained is an index that guides decision-makers to the best utilization of the zone in future.

  20. Combining several thermal indices to generate a unique heat comfort assessment methodology

    Directory of Open Access Journals (Sweden)

    Wissam EL Hachem

    2015-11-01

    Full Text Available Purpose: The proposed methodology hopes to provide a systematic multi-disciplinary approach to assess the thermal environment while minimizing unneeded efforts. Design/methodology/approach: Different factors affect the perception of the human thermal experience: metabolic rate (biology, surrounding temperatures (heat balance and environmental factors and cognitive treatment (physiology.This paper proposes a combination of different multidisciplinary variables to generate a unique heat comfort assessment methodology. The variables at stake are physiological, biological, and environmental. Our own heat analysis is thoroughly presented and all relevant equations are described. Findings: Most companies are oblivious about potential dangers of heat stress accidents and thus about methods to monitor and prevent them. This methodology enables the company or the concerned individual to conduct a preliminary assessment with minimal wasted resources and time in unnecessary steps whilst providing a guideline for a detailed study with minimal error rates if needed. More so, thermal comfort is an integral part of sound ergonomics practices, which in turn are decisive for the success of any lean six sigma initiative. Research limitations/implications: This methodology requires several full implementations to finalize its design. Originality/value: Most used heat comfort models are inherently uncertain and tiresome to apply. An extensive literature review confirms the need for a uniform assessment methodology that combines the different thermal comfort models such as the Fanger comfort model (PMV, PPD and WGBT since high error rates coupled with tiresome calculations often hinder the thermal assessment process.

  1. Combining remote sensing and on-site monitoring methods to investigate footpath erosion within a popular recreational heathland environment.

    Science.gov (United States)

    Rodway-Dyer, Sue; Ellis, Nicola

    2018-06-01

    Footpaths are a prominent consequence of natural area tourism and reflect damage caused to valuable, sensitive habitats by people pressure. Degradation impacts on vegetation, wildlife, on and off-site soil movement and loss, creation of additional informal off-path footpaths (desire lines), and visual destruction of landscapes. Impacts need to be measured and monitored on a large temporal and spatial scale to aid in land management to maintain access and preserve natural environments. This study combined remote sensing (Light Detection and Ranging [LiDAR] and aerial photography) with on-site measurement of footpaths within a sensitive heathland habitat (Land's End, Cornwall, UK). Soil loss, slope angle change, vegetation damage and a hydrology model were combined to comprehensively study the site. Results showed 0.09 m mean soil loss over five years, footpath widening, increasing grass cover into heathland, and water channelling on the footpaths exacerbating erosion. The environments surrounding the footpaths were affected with visitors walking off path, requiring further management and monitoring. Multiple remote sensing techniques were highly successful in comprehensively assessing the area, particularly the hydrology model, demonstrating the potential of providing a valuable objective and quantitative monitoring and management tool. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. The current suggestions on amending the new Act on Combined Heat and Power Generation; Die aktuellen Vorschlaege zur Novellierung der Kraft-Waerme-Kopplungsgesetzes

    Energy Technology Data Exchange (ETDEWEB)

    Lamfried, D. [Lueneburg Univ. (Germany)

    2007-10-15

    In the contribution under consideration the author reports on current suggestions on amending the new Act on Combined Heat and Power Generation (KWKG). In particular, the design by the Federal Ministry of Economics and Technology (BMWi, Berlin, Federal Republic of Germany) is interesting. The vote on the direct financial voting according to KWKG with the indirect instrument of emission trade underlines the denotation of the emission trade. Nevertheless, the design of the BMWi cannot be considered as a conclusive concept of the financial support. The emission trade does not offer sufficient financial terms of reference with respect to the extension of the KWKG. It has no control effects. The current version of the BMWi does not go beyond the valid rights decisively. The application of the 10 MW threshold results into an enormous retrogressive step in the financial support of the modernization of stock plants. There exists some reasons according to a continuing legal procedure. The expansion of the utilization of the combined heat and power generation in the production of electricity in the Federal Republic of Germany has a great potential in the reduction of emission of CO{sub 2}.

  3. Stochastic analysis of residential micro combined heat and power system

    DEFF Research Database (Denmark)

    Karami, H.; Sanjari, M. J.; Gooi, H. B.

    2017-01-01

    In this paper the combined heat and power functionality of a fuel-cell in a residential hybrid energy system, including a battery, is studied. The demand uncertainties are modeled by investigating the stochastic load behavior by applying Monte Carlo simulation. The colonial competitive algorithm...... algorithm. The optimized scheduling of different energy resources is listed in an efficient look-up table for all time intervals. The effects of time of use and the battery efficiency and its size are investigated on the operating cost of the hybrid energy system. The results of this paper are expected...

  4. Inactivation of Nondesiccated and Desiccated Cronobacter sakazakii in Reconstituted Infant Formula by Combination of Citral and Mild Heat.

    Science.gov (United States)

    Shi, Chao; Jia, Zhenyu; Sun, Yi; Chen, Yifei; Guo, Du; Liu, Zhiyuan; Wen, Qiwu; Guo, Xiao; Ma, Linlin; Yang, Baowei; Baloch, Allah Bux; Xia, Xiaodong

    2017-07-01

    The objective of this study was to evaluate the combined effect of citral plus mild heat on nondesiccated and desiccated Cronobacter sakazakii in reconstituted infant formula. Various concentrations of citral (0, 0.3, 0.6, and 0.9%) combined with various temperatures (25, 45, 50, and 55°C) were applied to nondesiccated and desiccated cocktails of three C. sakazakii strains (approximately 6.0 log CFU mL -1 ) in reconstituted infant formula, and the bacterial populations were assayed periodically. The combined treatments had marked antimicrobial effects on C. sakazakii compared with the control. Desiccated cells were more susceptible to citral than were nondesiccated cells in reconstituted infant formula. These findings suggest there is a potential application of citral in combination with mild heat to control C. sakazakii during preparation of reconstituted infant formula.

  5. New market based price regulation on combined heat and power in Denmark

    International Nuclear Information System (INIS)

    Koch, Jesper; Nielsen, Marianne; Hansen, Anders B.; Lawaetz, Henrik

    2003-01-01

    Major economic risks can become reality when local co-generation plants (L-CHP ) meet the full market penetration with new market based price regulation. Co-generation produces more than 50% of the national electricity consumption and half of the production is generated from L-CHP. The new price regulation is assumed to take action in 2004. The paper will present an analysis of a market based price regulation on the L-CHP-sector. The paper will spotlight on L-CHP in district heating systems supplying heat for domestic purposes. When smaller and medium sized CHP sell electricity they are paid an average price of 46 Euro per MWh. The return of selling electricity shall primarily cover the expenditure of buying gas for electricity production and writing off investments cost of a CHP-plant. With the framework of today it is a fact that the plants (in average) are only slightly competitive compared to individual heat production plants. When CHP meet market conditions there is a high risk that electricity prices will be reduced significantly (prices of 20 - 30 Euro per MWh) for a longer period. Significantly reduced electricity prices will result in dramatically increased heat prices. If no action is taken there will be a potential risk that heat consumers in the smaller and medium sized cities together must pay an extra bill of 200 million Euro each year. It corresponds to an average increase of the heating bill of 300 - 500 Euro per year for an average house. This is far from acceptable. There will also be a high risk that companies with industrial CHP will permanently convert to heat only boiler and only use their CHP occasionally because CHP plants might not be cost-effective when electricity prices are low. These effects can cause a significant increase of the national CO 2 emission

  6. The combined effect of gamma radiation and heat on some biological aspects of onion bulb fly Eumerus amoenus Loew

    International Nuclear Information System (INIS)

    El-Orabi, M.N.; Gharieb, O.H.; Hamza, A.F.H.; El-Saeadi, A.A.; Hussain, A.E.

    2010-01-01

    The effect of sub-sterilizing doses of gamma radiation, in combination with three degrees of temperature (20, 25 and 30 degree C). on some biological parameters of Eumerus Amoenus Loew were studied. The combined effect of radiation and heat were carried out on developmental stages namely; larval, pupal stages. Larval duration decreased significantly by increasing rearing temperature and increased by raising heat regardless larval instar. The same trend was observed in percent pupation, percent emergence. Irradiation of larvae decreases the adult emergence percentage under all temperatures. The results indicate that no adult male emergence when irradiated 4-d-old larvae at all doses when kept at 20 and 25 degree C. life-span of adults emerged from pupae irradiated as 5 and 7 day-old with sterilizing and sub-sterilizing doses was affected depending upon the dose level, temperatures and age of pupae at the time of irradiation. Fecundity of a female decreased by decreasing temperature degree or increasing radiation dose. Also, fertility of males decreased by radiation dose and by mating to irradiated females, this decrease was increased by increasing age of male and by decreasing temperature

  7. Study on diverse passive decay heat removal approach and principle

    International Nuclear Information System (INIS)

    Lin Qian; Si Shengyi

    2012-01-01

    Decay heat removal in post-accident is one of the most important aspects concerned in the reactor safety analysis. Passive decay heat removal approach is used to enhance nuclear safety. In advanced reactors, decay heat is removed by multiple passive heat removal paths through core to ultimate heat sink by passive residual heat removal system, passive injection system, passive containment cooling system and so on. Various passive decay heat removal approaches are summarized in this paper, the common features and differences of their heat removal paths are analyzed, and the design principle of passive systems for decay heat removal is discussed. It is found that. these decay heat removal paths is combined by some basic heat transfer processes, by the combination of these basic processes, diverse passive decay heat removal approach or system design scheme can be drawn. (authors)

  8. Encouraging Combined Heat and Power in California Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Groissbock, Markus [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Cardoso, Goncalo [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Muller, Andreas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lai, Judy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-02-01

    Governor Brown’s research priorities include an additional 6.5 GW of combined heat and power (CHP) by 2030. As of 2009, roughly 0.25 GW of small natural gas and biogas fired CHP is documented by the Self-Generation Incentive Program (SGIP) database. The SGIP is set to expire, and the anticipated grid de-carbonization based on the development of 20 GW of renewable energy will influence the CHP adoption. Thus, an integrated optimization approach for this analysis was chosen that allows optimizing the adoption of distributed energy resources (DER) such as photovoltaics (PV), CHP, storage technologies, etc. in the California commercial sector from the building owners’ perspective. To solve this DER adoption problem the Distributed Energy Resources Customer Adoption Model (DER-CAM), developed by the Lawrence Berkeley National Laboratory and used extensively to address the problem of optimally investing and scheduling DER under multiple settings, has been used. The application of CHP at large industrial sites is well known, and much of its potential is already being realized. Conversely, commercial sector CHP, especially those above 50 to 100 kW peak electricity load, is widely overlooked. In order to analyze the role of DER in CO2 reduction, 147 representative sites in different climate zones were selected from the California Commercial End Use Survey (CEUS). About 8000 individual optimization runs, with different assumptions for the electric tariffs, natural gas costs, marginal grid CO2 emissions, and nitrogen oxide treatment costs, SGIP, fuel cell lifetime, fuel cell efficiency, PV installation costs, and payback periods for investments have been performed. The most optimistic CHP potential contribution in this sector in 2020 will be 2.7 GW. However, this result requires a SGIP in 2020, 46% average electric efficiency for fuel cells, a payback period for investments of 10 years, and a CO2 focused approach of the building owners. In

  9. Promoting investments in combined heat and power production in East-European countries

    International Nuclear Information System (INIS)

    Van Oostvoom, F.; Van Harmelen, T.

    1992-01-01

    The study concerns the evaluation of the potential of Combined Heat and Power (CHP) locations, both in industry and district heating with a heat demand of at least 20 GJ/h or ca. 1 MWe capacity. In fact 58 Hungarian locations were analyzed on scope and profitability for investment in CHP, using financial accounting models and criteria such as Internal Rate of Return and Pay-back Period. Due to the already existing favourable infrastructure in East European countries the present expectations in Hungary about the CHP capacity to be developed in the future are very optimistic (1300 up till 2000 MWe in the year 2000). Clearly there exist an overoptimism concerning the possibilities of increasing the energy efficiency in former East-European countries by investment in cogeneration. A more financially and economic attractive way for efficiency improvements is promoting energy saving in these countries and thus avoiding investments in supply technologies. 6 refs

  10. Combined generation of electric and heating energy in future development of Yugoslav energy sector until 2000

    International Nuclear Information System (INIS)

    Djajic, Nenad; Zivanovic, Vladimir

    2000-01-01

    Development of the district heating system in the FR Yugoslavia, beside the combined generation of electric and heating energy presents a necessity for energy, economic and ecological reasons. Although the structure of energy reserves is rather unfavourable considering that the lignite is being predominantly used, available reserves of energy raw material are able to ensure the long-term development of Yugoslav energy sector, and to offer real possibilities for considerable substitution of foreign good quality fuels, especially in district heating systems. Their further development will depend, among other things: on the implementation of new technological solutions for the exploitation of local energy resources; need of reconstruction, revitalisation and transformation of old condensing thermal power plants into the cogeneration plants; installation of remote controlled transmission of heating energy as well as on development of heating plants and smaller co-generation plants based on local energy resources. (Authors)

  11. Heat-flow and lateral seismic-velocity heterogeneities near Deep Sea Drilling Project-Ocean Drilling Program Site 504

    Science.gov (United States)

    Lowell, Robert P.; Stephen, Ralph A.

    1991-11-01

    Both conductive heat-flow and seismic-velocity data contain information relating to the permeability of the oceanic crust. Deep Sea Drilling Project-Ocean Drilling Program Site 504 is the only place where both detailed heat-flow and seismic-velocity field studies have been conducted at the same scale. In this paper we examine the correlation between heat flow and lateral heterogeneities in seismic velocity near Site 504. Observed heterogeneities in seismic velocity, which are thought to be related to variations in crack density in the upper 500 m of the basaltic crust, show little correlation with the heat-flow pattern. This lack of correlation highlights some of the current difficulties in using seismic-velocity data to infer details of spatial variations in permeability that are significant in controlling hydrothermal circulation.

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

    OpenAIRE

    Costante Mario Invernizzi; Nadeem Ahmed Sheikh

    2018-01-01

    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 eng...

  13. Simulating conditions for combined heat and power in the Swedish district heating sector

    International Nuclear Information System (INIS)

    Knutsson, David

    2005-01-01

    The most important issues in the European energy sector today are how to increase competitiveness on the energy markets, reduce both CO2 emissions and dependence on imported fuels. These issues are also important aspects of Swedish energy policy. In Sweden, the district heating (DH) sector has commonly been used to achieve Swedish energy policy goals. However, the ongoing integration and deregulation of the energy markets in Europe now means that the Swedish DH sector can also play an important role in achieving international targets. This thesis investigates the extent to which the Swedish DH sector can contribute to compliance with current energy policy targets, both international and Swedish. The study consisted of simulations of the Swedish DH sector response to various policy instruments in a model that takes the local features of virtually all Swedish DH systems into account. The findings show, for example, that there is great potential for combined heat and power (CHP) generation in the Swedish DH sector. By exporting this CHP electricity to other European countries with less effective and fossil dependent power generation plants, the CO2 emissions from the European energy sector could be substantially reduced. This would also result in increased security of supply and competitiveness in the EU, since fuel use would be more effective. In Sweden, increased CHP generation would also be a way of maintaining an effective national security of supply of power

  14. The Heat Transfer Coefficient of Recycled Concrete Bricks Combination with EPS Insulation Board Wall

    Directory of Open Access Journals (Sweden)

    Jianhua Li

    2015-01-01

    Full Text Available Four tectonic forms samples were conducted to test their heat transfer coefficients. By analyzing and comparing the test values and theoretical values of the heat transfer coefficient, a corrected-value calculation method for determining the heat transfer coefficient was proposed; the proposed method was proved to be reasonably correct. The results indicated that the recycled concrete brick wall heat transfer coefficient is higher than that of the clay brick wall, the heat transfer coefficient of recycled concrete brick wall could be effectively reduced when combined with the EPS insulation board, and the sandwich insulation type was better than that of external thermal insulation type.

  15. Production planning of combined heat and power plants with regards to electricity price spikes : A machine learning approach

    OpenAIRE

    Fransson, Nathalie

    2017-01-01

    District heating systems could help manage the expected increase of volatility on the Nordic electricity market by starting a combined heat and power production plant (CHP) instead of a heat only production plant when electricity prices are expected to be high. Fortum Värme is interested in adjusting the production planning of their district heating system more towards high electricity prices and in their system there is a peak load CHP unit that could be utilised for this purpose. The econom...

  16. Combined Heat and Power Systems for the Provision of Sustainable Energy from Biomass in Buildings

    OpenAIRE

    Ortwein Andreas

    2016-01-01

    Against the background of greenhouse gases causing climate change, combined heat and power (CHP) systems fueled by biomass can efficiently supply energy with high flexibility. Such CHP systems will usually consist of one or more thermo-chemical conversion steps and at least one (the more or less separated) electric power generation unit. Depending on the main products of the previous conversion steps (e.g. combustible gases or liquids, but also flue gases with sensible heat), different techno...

  17. Large Combined Heat and Power Plants for Sustainable Energy System

    DEFF Research Database (Denmark)

    Lund, Rasmus Søgaard; Mathiesen, Brian Vad

    . CHP (combined heat and power) plants in Denmark will change their role from base load production to balancing the fluctuation in renewable energy supply, such as wind power and at the same time they have to change to renewable energy sources. Some solutions are already being planned by utilities...... in Denmark; conversion of pulverised fuel plants from coal to wood pellets and a circulating fluidised bed (CFB) plant for wood chips. From scientific research projects another solution is suggested as the most feasible; the combined cycle gas turbine (CCGT) plant. In this study a four scenarios...

  18. Size effects on cation heats of formation. I. Methyl substitutions in nitrogenous compounds

    International Nuclear Information System (INIS)

    Leach, Sydney

    2012-01-01

    Graphical abstract: Heat of formation of cations as a function of ln(n) where n is the number of atoms in the ion: methyl substituted immonium cations. N = substitution at nitrogen sites, C = substitution at carbon sites. Highlights: ► Heats of formation of nitrogenous cations by graphical method relating to ion size. ► Methyl substitution in formamides, acetamides, immonium, amine, and imine cations. ► Methyl substitution in ammonium and amino cations. ► New studies ionization energies and heats of formation required in several cases. - Abstract: The heats of formation of molecular ions are often not known to better than 10 or 20 kJ/mol. The present study on nitrogenous compounds adopts the graphical approach of Holmes and Lossing which relates cation heats of formation to cation size. A study of methyl substitution in formamides and acetamides is followed by an examination of heat of formation data on carbon-site and nitrogen-site methyl substitution in immonium, amine, imine, ammonium and amino cations. The results provide tests of the validity of this graphical method and also suggest investigating or re-investigating the ionization energies and the heats of formation of several of the molecules studied.

  19. Combined heat and power generation with a HCPV system at 2000 suns

    International Nuclear Information System (INIS)

    Paredes, Filippo; Montagnino, Fabio M.; Milone, Sergio; Salinari, Piero; Agnello, Simonpietro; Gelardi, Franco M.; Sciortino, Luisa; Cannas, Marco; Bonsignore, Gaetano; Barbera, Marco; Collura, Alfonso; Lo Cicero, Ugo

    2015-01-01

    This work shows the development of an innovative solar CHP system for the combined production of heat and power based upon HCPV modules working at the high concentration level of 2000 suns. The solar radiation is concentrated on commercial InGaP/InGaAs/Ge triple-junction solar cells designed for intensive work. The primary optics is a rectangular off-axis parabolic mirror while a secondary optic at the focus of the parabolic mirror is glued in optical contact with the cell. Each module consist of 2 axis tracker (Alt-Alt type) with 20 multijunction cells each one integrated with an active heat sink. The cell is connected to an active heat transfer system that allows to keep the cell at a high level of electrical efficiency (ηel > 30 %), bringing the heat transfer fluid (water and glycol) up to an output temperature of 90°C. Accordingly with the experimental data collected from the first 1 kWe prototype, the total amount of extracted thermal energy is above the 50% of the harvested solar radiation. That, in addition the electrical efficiency of the system contributes to reach an overall CHP efficiency of more than the 80%

  20. Combined heat and power generation with a HCPV system at 2000 suns

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, Filippo; Montagnino, Fabio M.; Milone, Sergio [IDEA s.r.l., C.da Molara Z.I. III Fase, 90018 Termini Imerese (Italy); Salinari, Piero; Agnello, Simonpietro; Gelardi, Franco M.; Sciortino, Luisa; Cannas, Marco [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, 90123 Palermo (Italy); Bonsignore, Gaetano; Barbera, Marco [Dipartimento di Fisica e Chimica, Università di Palermo, Via Archirafi 36, 90123 Palermo (Italy); INAF, Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo (Italy); Collura, Alfonso; Lo Cicero, Ugo [INAF, Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, 90134 Palermo (Italy)

    2015-09-28

    This work shows the development of an innovative solar CHP system for the combined production of heat and power based upon HCPV modules working at the high concentration level of 2000 suns. The solar radiation is concentrated on commercial InGaP/InGaAs/Ge triple-junction solar cells designed for intensive work. The primary optics is a rectangular off-axis parabolic mirror while a secondary optic at the focus of the parabolic mirror is glued in optical contact with the cell. Each module consist of 2 axis tracker (Alt-Alt type) with 20 multijunction cells each one integrated with an active heat sink. The cell is connected to an active heat transfer system that allows to keep the cell at a high level of electrical efficiency (ηel > 30 %), bringing the heat transfer fluid (water and glycol) up to an output temperature of 90°C. Accordingly with the experimental data collected from the first 1 kWe prototype, the total amount of extracted thermal energy is above the 50% of the harvested solar radiation. That, in addition the electrical efficiency of the system contributes to reach an overall CHP efficiency of more than the 80%.

  1. Combined heat and power generation with a HCPV system at 2000 suns

    Science.gov (United States)

    Paredes, Filippo; Montagnino, Fabio M.; Salinari, Piero; Bonsignore, Gaetano; Milone, Sergio; Agnello, Simonpietro; Barbera, Marco; Gelardi, Franco M.; Sciortino, Luisa; Collura, Alfonso; Lo Cicero, Ugo; Cannas, Marco

    2015-09-01

    This work shows the development of an innovative solar CHP system for the combined production of heat and power based upon HCPV modules working at the high concentration level of 2000 suns. The solar radiation is concentrated on commercial InGaP/InGaAs/Ge triple-junction solar cells designed for intensive work. The primary optics is a rectangular off-axis parabolic mirror while a secondary optic at the focus of the parabolic mirror is glued in optical contact with the cell. Each module consist of 2 axis tracker (Alt-Alt type) with 20 multijunction cells each one integrated with an active heat sink. The cell is connected to an active heat transfer system that allows to keep the cell at a high level of electrical efficiency (ηel > 30 %), bringing the heat transfer fluid (water and glycol) up to an output temperature of 90°C. Accordingly with the experimental data collected from the first 1 kWe prototype, the total amount of extracted thermal energy is above the 50% of the harvested solar radiation. That, in addition the electrical efficiency of the system contributes to reach an overall CHP efficiency of more than the 80%.

  2. Solar air heating system for combined DHW and space heating

    Energy Technology Data Exchange (ETDEWEB)

    Oestergaard Jensen, S.; Bosanac, M.

    2002-12-01

    The project deals with the development and testing of a simple system for utilization of the summer excess heat from small solar air heating systems for preheating of fresh air. The principle of the system is to lead the heated air down around a domestic hot water tank letting the surface of the tank act as heat exchanger between the air and the water. In order to increase the heat transfer, coefficient fins into the air stream were mounted on the tank. A complete system with 3 m{sup 2} solar air collector, ductworks and a 85 litre storage were set up and extensively monitored. The air stream through the system was created by a fan connected directly to one or two PV-panels leading to a solar radiation dependent flow rate without the use of any other control. Based on monitoring results the system was characterized and a TRNSYS model of the system was developed and calibrated/validated. The monitoring and the simulations with the TRNSYS model revealed several interesting things about the system. The monitoring revealed that the system is capable of bringing the temperature of the water in the storage above 60 deg. C at warm days with clear sky conditions. The storage is very stratified, which is beneficial as usable hot water temperatures rather quickly are obtained. The performance was highly dependent on the airflow rate through the system. It can be concluded that the investigated system will have a performance in the order of 500 kWh during the winter, spring and autumn months and around 250 kWh during the four summer months - or in total a yearly performance of 750 kWh/m{sup 2}. A small traditional solar heating system for preheating of domestic hot water would have a higher performance during the four summer months, but no performance during the rest of the year if the system is installed in a summer house, which only is occupied during the summer. The parametric analysis further indicates that it is possible to further optimise the system when the thermal

  3. Some technological aspects of combined processing of meat by heat and ionizing radiations

    International Nuclear Information System (INIS)

    Gel'fand, S.Yu.; Nomenotskaya, N.F.; Mozul', M.Ya.

    1974-01-01

    The paper discusses the use of ionizing radiation to prolong the storage life of meat and meat products. Irradiating raw meat with doses of 0.4-0.6 Mrad increased storage life up to two months at low above-zero C temperatures. The difficulty of inhibiting autolytic processes during storage of irradiated raw meat led to searches for combined methods of meat treatment. A series of experiments was staged with pre-irradiation heating of meat up to 75, 77, and 80 0 C in order to see how cathepsin activity is affected by the duration and temperature of heating in the case of combined treatment. To increase the resistance of meat products to microbial damage, tests were carried out in which meat was exposed to short-term but intensive heat by immersing it in hot (130-160 0 C) vegetable oil (frying grease). The results are presented in the form of tables and diagrams. (E.T.)

  4. District heating

    International Nuclear Information System (INIS)

    Hansen, L.

    1993-01-01

    The environmental risks and uncertainties of a high-energy future are disturbing and give rise to several reservations concerning the use of fossil fuels. A number of technologies will help to reduce atmospheric pollution. In Denmark special importance is attached to the following: Energy conservation. Efficient energy conversion. Renewable energy sources. District heating, combined production of heat and power. Many agree that district heating (DH), produced by the traditional heat-only plant, and combined heat and power (CHP) have enormous potential when considering thermal efficiency and lowered environmental impacts: The basic technology of each is proven, it would be relatively simple to satisfy a substantial part of the energy demand, and their high efficiencies mean reduced pollution including greenhouse gas emissions. This is especially important in high population density areas - the obviously preferred sites for such energy generation. Compared with individual heating DH can provide a community with an operationally efficient and most often also an economically competitive heat supply. This is particularly true under the circumstances where the DH system is supplied from CHP plants. Their use results in very substantial improvements in overall efficiency. Further environmental improvements arise from the reduced air pollution obtainable in reasonably large CHP plants equipped with flue gas cleaning to remove particles, sulphur dioxide, and nitrogen acids. As a consequence of these considerations, DH plays an important role in fulfilling the space and water heating demand in many countries. This is especially the case in Denmark where this technology is utilised to a very great extent. Indeed, DH is one of the reasons why Denmark has relatively good air quality in the cities. (au)

  5. Heat of fusion storage systems for combined solar systems in low energy buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2004-01-01

    Solar heating systems for combined domestic hot water and space heating has a large potential especially in low energy houses where it is possible to take full advantage of low temperature heating systems. If a building integrated heating system is used – e.g. floor heating - the supply temperature...... from solid to liquid form (Fig. 1). Keeping the temperature as low as possible is an efficient way to reduce the heat loss from the storage. Furthermore, the PCM storage might be smaller than the equivalent water storage as more energy can be stored per volume. If the PCM further has the possibility...... systems through further improvement of water based storages and in parallel to investigate the potential of using storage designs with phase change materials, PCM. The advantage of phase change materials is that large amounts of energy can be stored without temperature increase when the material is going...

  6. Simulation and optimization study on a solar space heating system combined with a low temperature ASHP for single family rural residential houses in Beijing

    DEFF Research Database (Denmark)

    Deng, Jie; Tian, Zhiyong; Fan, Jianhua

    2016-01-01

    A pilot project of the solar water heating system combined with a low temperature air source heat pump (ASHP) unit was established in 2014 in a detached residential house in the rural region of Beijing, in order to investigate the system application prospect for single family houses via system...... optimization design and economic analysis. The established system was comprised of the glass heat-pipe based evacuated tube solar collectors with a gross area of 18.8 m2 and an ASHP with a stated heating power of 8 kW for the space heating of a single family rural house of 81.4 m2. The dynamic thermal...... with good building insulation were undertaken to figure out the system economical efficiency in the rural regions of Beijing. The results show that the payback periods of the solar space heating system combined with the ASHP with the collector areas 15.04-22.56 m2 are 17.3-22.4 years for the established...

  7. Carbon Emissions Trading and Combined Heat and Power Strategies: Unintended Consequences

    Science.gov (United States)

    Tysseling, John C.; Vosevich, Mary; Boersma, Benjamin R.; Zumwalt, Jefferey A.

    2009-01-01

    Facility professionals continuously search for projects that reduce energy consumption and operating costs so as to directly benefit their bottom line. Many institutions nationwide have contemplated or made investments in combined heat and power (CHP) projects as a life-cycle strategy to minimize operating costs. However, recent sustainability and…

  8. Preliminary project concerning the straw-fueled combined power-heat plant to be constructed at Glamsbjerg

    International Nuclear Information System (INIS)

    Gabriel, S.; Koch, T.

    1994-06-01

    Power and heat generation based on biomass gasification is of great importance due to its beneficial environmental effects and good economy. This report concerns a preliminary project on feasibility and problems of implementing a dual-purpose power plant, supplying both power and district heating to several schools, swimming pools and other public facilities at Glamsbjerg (Funen). The plant is to be based on thermal gasification (pyrolysis) of straw and use of the gas in a diesel engine. The diesels operate the power generator, and their waste heat should be utilized in the local district heating network. In order to establish a stable and flexible straw supply to the plant an evaluation of resources in the area has been carried out. Apart from straw-derived fuel the plant is planned to use natural gas for start and maintenance of the process. The prices of the combined plant and of the fuel processing are estimated in the report. (EG)

  9. Wood chip drying in connection with combined heat and power or solar energy in Finland

    Directory of Open Access Journals (Sweden)

    Rinne Samuli

    2014-01-01

    Full Text Available 20% of the Finnish district heating (DH power plant fuels are wood-based and the share is increasing. The wood fuel demand probably exceeds the potential supply in the future. The wood fuel drying with waste heat is one profitable opportunity to gain more wood fuel. If the drying energy can be produced with lower primary energy use than combusting the fuel directly, the drying potentially improves the system efficiency. In this study, the drying feasibility in the connection of a combined heat and power (CHP system, possibly with solar collectors, is calculated. The wood fuel heating can be increased profitably by 6%, using the heat from CHP for drying only when the marginal cost of the heat is low enough, i.e. the electricity price is high enough and there is free capacity after the DH demand. Although the drying is profitable, a larger heat storage can also increase the annual result similarly. The best investment choice depends on the plant properties. Here the optimal system enables 20% DH production cost savings. Solar heat may be profitable, when the solar heat has a 2–3% share of the annual heat demand. However, the dryer or larger storage tank are more profitable investments.

  10. A new desalination system using a combination of heat pipe, evacuated tube and parabolic trough collector

    International Nuclear Information System (INIS)

    Jafari Mosleh, H.; Jahangiri Mamouri, S.; Shafii, M.B.; Hakim Sima, A.

    2015-01-01

    Highlights: • A new desalination uses a combination of heat pipe and parabolic trough collector. • A twin-glass evacuated tube is used to decrease the thermal losses from heat pipe. • Adding oil into the space between heat pipe and tube collector enhances the yield. • The yield and efficiency reach up to 0.933 kg/(m 2 h) and 65.2%, respectively. - Abstract: The solar collectors have been commonly used in desalination systems. Recent investigations show that the use of a linear parabolic trough collector in solar stills can improve the efficiency of a desalination system. In this work, a combination of a heat pipe and a twin-glass evacuated tube collector is utilized with a parabolic trough collector. Results show that the rate of production and efficiency can reach to 0.27 kg/(m 2 h) and 22.1% when aluminum conducting foils are used in the space between the heat pipe and the twin-glass evacuated tube collector to transfer heat from the tube collector to the heat pipe. When oil is used as a medium for the transfer of heat, filling the space between heat pipe and twin-glass evacuated tube collector, the production and efficiency can increase to 0.933 kg/(m 2 h) and 65.2%, respectively

  11. Magnetic configuration effects on the edge heat flux in the limiter plasma on W7-X measured using the infrared camera and the combined probe

    Science.gov (United States)

    P, DREWS; H, NIEMANN; J, COSFELD; Y, GAO; J, GEIGER; O, GRULKE; M, HENKEL; D, HÖSCHEN; K, HOLLFELD; C, KILLER; A, KRÄMER-FLECKEN; Y, LIANG; S, LIU; D, NICOLAI; O, NEUBAUER; M, RACK; B, SCHWEER; G, SATHEESWARAN; L, RUDISCHHAUSER; N, SANDRI; N, WANG; the W7-X Team

    2018-05-01

    Controlling the heat and particle fluxes in the plasma edge and on the plasma facing components is important for the safe and effective operation of every magnetically confined fusion device. This was attempted on Wendelstein 7-X in the first operational campaign, with the modification of the magnetic configuration by use of the trim coils and tuning the field coil currents, commonly named iota scan. Ideally, the heat loads on the five limiters are equal. However, they differ between each limiter and are non-uniform, due to the (relatively small) error fields caused by the misalignment of components. It is therefore necessary to study the influence of the configuration changes on the transport of heat and particles in the plasma edge caused by the application of error fields and the change of the magnetic configuration. In this paper the up-stream measurements conducted with the combined probe are compared to the downstream measurements with the DIAS infrared camera on the limiter.

  12. Heat pipe effects in nuclear waste isolation: a review

    International Nuclear Information System (INIS)

    Doughty, C.; Pruess, K.

    1985-12-01

    The existence of fractures favors heat pipe development in a geologic repository as does a partially saturated medium. A number of geologic media are being considered as potential repository sites. Tuff is partially saturated and fractured, basalt and granite are saturated and fractured, salt is unfractured and saturated. Thus the most likely conditions for heat pipe formation occur in tuff while the least likely occur in salt. The relative permeability and capillary pressure dependences on saturation are of critical importance for predicting thermohydraulic behavior around a repository. Mineral redistribution in heat pipe systems near high-level waste packages emplaced in partially saturated formations may significantly affect fluid flow and heat transfer processes, and the chemical environment of the packages. We believe that a combined laboratory, field, and theoretical effort will be needed to identify the relevant physical and chemical processes, and the specific parameters applicable to a particular site. 25 refs., 1 fig

  13. Heat demand profiles of energy conservation measures in buildings and their impact on a district heating system

    International Nuclear Information System (INIS)

    Lundström, Lukas; Wallin, Fredrik

    2016-01-01

    Highlights: • Energy savings impact on an low CO 2 emitting district heating system. • Heat profiles of eight building energy conservation measures. • Exhaust air heat pump, heat recovery ventilation, electricity savings etc. • Heat load weather normalisation with segmented multivariable linear regression. - Abstract: This study highlights the forthcoming problem with diminishing environmental benefits from heat demand reducing energy conservation measures (ECM) of buildings within district heating systems (DHS), as the supply side is becoming “greener” and more primary energy efficient. In this study heat demand profiles and annual electricity-to-heat factors of ECMs in buildings are computed and their impact on system efficiency and greenhouse gas emissions of a Swedish biomass fuelled and combined heat and power utilising DHS are assessed. A weather normalising method for the DHS heat load is developed, combining segmented multivariable linear regressions with typical meteorological year weather data to enable the DHS model and the buildings model to work under the same weather conditions. Improving the buildings’ envelope insulation level and thereby levelling out the DHS heat load curve reduces greenhouse gas emissions and improves primary energy efficiency. Reducing household electricity use proves to be highly beneficial, partly because it increases heat demand, allowing for more cogeneration of electricity. However the other ECMs considered may cause increased greenhouse gas emissions, mainly because of their adverse impact on the cogeneration of electricity. If biomass fuels are considered as residuals, and thus assigned low primary energy factors, primary energy efficiency decreases when implementing ECMs that lower heat demand.

  14. Assessment of Nucleation Site Density Models for CFD Simulations of Subcooled Flow Boiling

    International Nuclear Information System (INIS)

    Hoang, N. H.; Chu, I. C.; Euh, D. J.; Song, C. H.

    2015-01-01

    The framework of a CFD simulation of subcooled flow boiling basically includes a block of wall boiling models communicating with governing equations of a two-phase flow via parameters like temperature, rate of phasic change, etc. In the block of wall boiling models, a heat flux partitioning model, which describes how the heat is taken away from a heated surface, is combined with models quantifying boiling parameters, i.e. nucleation site density, and bubble departure diameter and frequency. It is realized that the nucleation site density is an important parameter for predicting the subcooled flow boiling. The number of nucleation sites per unit area decides the influence region of each heat transfer mechanism. The variation of the nucleation site density will mutually change the dynamics of vapor bubbles formed at these sites. In addition, the nucleation site density is needed as one initial and boundary condition to solve the interfacial area transport equation. A lot of effort has been devoted to mathematically formulate the nucleation site density. As a consequence, numerous correlations of the nucleation site density are available in the literature. These correlations are commonly quite different in their mathematical form as well as application range. Some correlations of the nucleation site density have been applied successfully to CFD simulations of several specific subcooled boiling flows, but in combination with different correlations of the bubble departure diameter and frequency. In addition, the values of the nucleation site density, and bubble departure diameter and frequency obtained from simulations for a same problem are relatively different, depending on which models are used, even when global characteristics, e.g., void fraction and mean bubble diameter, agree well with experimental values. It is realized that having a good CFD simulations of the subcooled flow boiling requires a detailed validations of all the models used. Owing to the importance

  15. Perceived heat stress and health effects on construction workers.

    Science.gov (United States)

    Dutta, Priya; Rajiva, Ajit; Andhare, Dileep; Azhar, Gulrez Shah; Tiwari, Abhiyant; Sheffield, Perry

    2015-01-01

    Increasing heat waves-particularly in urban areas where construction is most prevalent, highlight a need for heat exposure assessment of construction workers. This study aims to characterize the effects of heat on construction workers from a site in Gandhinagar. This study involved a mixed methods approach consisting of a cross sectional survey with anthropometric measurements (n = 219) and four focus groups with construction workers, as well as environmental measurements of heat stress exposure at a construction site. Survey data was collected in two seasons i.e., summer and winter months, and heat illness and symptoms were compared between the two time periods. Thematic coding of focus group data was used to identify vulnerability factors and coping mechanisms of the workers. Heat stress, recorded using a wet bulb globe temperature monitor, was compared to international safety standards. The survey findings suggest that heat-related symptoms increased in summer; 59% of all reports in summer were positive for symptoms (from Mild to Severe) as compared to 41% in winter. Focus groups revealed four dominant themes: (1) Non-occupational stressors compound work stressors; (2) workers were particularly attuned to the impact of heat on their health; (3) workers were aware of heat-related preventive measures; and (4) few resources were currently available to protect workers from heat stress. Working conditions often exceed international heat stress safety thresholds. Female workers and new employees might be at increased risk of illness or injury. This study suggests significant health impacts on construction workers from heat stress exposure in the workplace, showed that heat stress levels were higher than those prescribed by international standards and highlights the need for revision of work practices, increased protective measures, and possible development of indigenous work safety standards for heat exposure.

  16. The Added Economic and Environmental Value of Solar Thermal Systems in Microgrids with CombinedHeat and Power

    Energy Technology Data Exchange (ETDEWEB)

    Marnay, Chris; Stadler, Michael; Cardoso, Goncalo; Megel, Olivier; Lai, Judy; Siddiqui, Afzal

    2009-08-15

    The addition of solar thermal and heat storage systems can improve the economic, as well as environmental attraction of micro-generation systems, e.g. fuel cells with or without combined heat and power (CHP) and contribute to enhanced CO2 reduction. However, the interactions between solar thermal collection and storage systems and CHP systems can be complex, depending on the tariff structure, load profile, etc. In order to examine the impact of solar thermal and heat storage on CO2 emissions and annual energy costs, a microgrid's distributed energy resources (DER) adoption problem is formulated as a mixed-integer linear program. The objective is minimization of annual energy costs. This paper focuses on analysis of the optimal interaction of solar thermal systems, which can be used for domestic hot water, space heating and/or cooling, and micro-CHP systems in the California service territory of San Diego Gas and Electric (SDG&E). Contrary to typical expectations, our results indicate that despite the high solar radiation in southern California, fossil based CHP units are dominant, even with forecast 2020 technology and costs. A CO2 pricing scheme would be needed to incent installation of combined solar thermal absorption chiller systems, and no heat storage systems are adopted. This research also shows that photovoltaic (PV) arrays are favored by CO2 pricing more than solar thermal adoption.

  17. The Added Economic and Environmental Value of Solar Thermal Systems in Microgrids with CombinedHeat and Power

    International Nuclear Information System (INIS)

    Marnay, Chris; Stadler, Michael; Cardoso, Goncalo; Megel, Olivier; Lai, Judy; Siddiqui, Afzal

    2009-01-01

    The addition of solar thermal and heat storage systems can improve the economic, as well as environmental attraction of micro-generation systems, e.g. fuel cells with or without combined heat and power (CHP) and contribute to enhanced CO2 reduction. However, the interactions between solar thermal collection and storage systems and CHP systems can be complex, depending on the tariff structure, load profile, etc. In order to examine the impact of solar thermal and heat storage on CO2 emissions and annual energy costs, a microgrid's distributed energy resources (DER) adoption problem is formulated as a mixed-integer linear program. The objective is minimization of annual energy costs. This paper focuses on analysis of the optimal interaction of solar thermal systems, which can be used for domestic hot water, space heating and/or cooling, and micro-CHP systems in the California service territory of San Diego Gas and Electric (SDG and amp;E). Contrary to typical expectations, our results indicate that despite the high solar radiation in southern California, fossil based CHP units are dominant, even with forecast 2020 technology and costs. A CO2 pricing scheme would be needed to incent installation of combined solar thermal absorption chiller systems, and no heat storage systems are adopted. This research also shows that photovoltaic (PV) arrays are favored by CO2 pricing more than solar thermal adoption.

  18. Heat Transfer Characteristics of SiC-coated Heat Pipe for Passive Decay Heat Removal

    International Nuclear Information System (INIS)

    Kim, Kyung Mo; Kim, In Guk; Jeong, Yeong Shin; Bang, In Cheol

    2014-01-01

    The main concern with the Fukushima accident was the failure of active and passive core cooling systems. The main function of existing passive decay heat removal systems is feeding additional coolant to the reactor core. Thus, an established emergency core cooling system (ECCS) cannot operate properly because of impossible depressurization under the station blackout (SBO) condition. Therefore, a new concept for passive decay heat removal system is required. In this study, an innovative hybrid control rod concept is considered for passive in-core decay heat removal that differs from the existing direct vessel injection core cooling system and passive auxiliary feedwater system (PAFS). The heat transfer between the evaporator and condenser sections occurs by phase change of the working fluid and capillary action induced by wick structures installed on the inner wall of the heat pipe. In this study, a hybrid control rod is developed to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and control rod. Previous studies on enhancing the heat removal capacity of heat pipes used nanofluids, self-rewetting fluids, various wick structures and condensers. Many studies have examined the thermal performances of heat pipes using various nanofluids. They concluded that the enhanced thermal performance of the heat pipe using nanofluids is due to nanoparticle deposition on the wick structures. Thus, the wick structure of heat pipes has been modified by nanoparticle deposition to enhance the heat removal capacity. However, previous studies used relatively small heat pipes and narrow ranges of heat loads. The environment of a nuclear reactor is very specific, and the decay heat produced by fission products after shutdown is relatively large. Thus, this study tested a large-scale heat pipe over a wide range of power. The concept of a hybrid heat pipe for an advanced in-core decay heat removal system was introduced for complete

  19. Heat Transfer Characteristics of SiC-coated Heat Pipe for Passive Decay Heat Removal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Mo; Kim, In Guk; Jeong, Yeong Shin; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    The main concern with the Fukushima accident was the failure of active and passive core cooling systems. The main function of existing passive decay heat removal systems is feeding additional coolant to the reactor core. Thus, an established emergency core cooling system (ECCS) cannot operate properly because of impossible depressurization under the station blackout (SBO) condition. Therefore, a new concept for passive decay heat removal system is required. In this study, an innovative hybrid control rod concept is considered for passive in-core decay heat removal that differs from the existing direct vessel injection core cooling system and passive auxiliary feedwater system (PAFS). The heat transfer between the evaporator and condenser sections occurs by phase change of the working fluid and capillary action induced by wick structures installed on the inner wall of the heat pipe. In this study, a hybrid control rod is developed to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and control rod. Previous studies on enhancing the heat removal capacity of heat pipes used nanofluids, self-rewetting fluids, various wick structures and condensers. Many studies have examined the thermal performances of heat pipes using various nanofluids. They concluded that the enhanced thermal performance of the heat pipe using nanofluids is due to nanoparticle deposition on the wick structures. Thus, the wick structure of heat pipes has been modified by nanoparticle deposition to enhance the heat removal capacity. However, previous studies used relatively small heat pipes and narrow ranges of heat loads. The environment of a nuclear reactor is very specific, and the decay heat produced by fission products after shutdown is relatively large. Thus, this study tested a large-scale heat pipe over a wide range of power. The concept of a hybrid heat pipe for an advanced in-core decay heat removal system was introduced for complete

  20. Combined Space and Water Heating: Next Steps to Improved Performance

    Energy Technology Data Exchange (ETDEWEB)

    Schoenbauer, B. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Bohac, D. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States); Huelman, P. [NorthernSTAR Building America Partnership, Minneapolis, MN (United States)

    2016-07-13

    A combined space- and water-heating (combi) system uses a high-efficiency direct-vent burner that eliminates safety issues associated with natural draft appliances. Past research with these systems shows that using condensing water heaters or boilers with hydronic air handling units can provide both space and water heating with efficiencies of 90% or higher. Improved controls have the potential to reduce complexity and improve upon the measured performance. This project demonstrates that controls can significantly benefit these first-generation systems. Laboratory tests and daily load/performance models showed that the set point temperature reset control produced a 2.1%-4.3% (20-40 therms/year) savings for storage and hybrid water heater combi systems operated in moderate-load homes.

  1. Simulation study of energetic ion distribution during combined NBI and ICRF heating in LHD

    International Nuclear Information System (INIS)

    Murakami, S.; Fukuyama, A.; Kasilov, V.

    2006-01-01

    In the LHD, significant performances of ICRF heating (fundamental, minority heating regime) have been demonstrated and up to 500keV of energetic tail ions have been observed by fast neutral particle analysis (NPA). These measured results indicate a good property of energetic ion confinement in helical systems. From the 9th campaign of LHD experiment (FY2005) a new perpendicular NBI heating system (P<3MW) has been installed and an effective heating of perpendicularly injected beam ions by the higher harmonics ICRF heating is expected. ICRF heating generates highly energetic tail ions, which drift around the torus for a long time (typically on a collisional time scale). Thus, the behavior of these energetic ions is strongly affected by the characteristics of the drift motions, which depend on the magnetic field configuration. In particular, in a three-dimensional (3D) magnetic configuration, complicated drift motions of trapped particles would play an important role in the confinement of the energetic ions and the ICRF heating process. Therefore a global simulation of ICRF heating is necessary for the accurate modeling of the plasma heating process in a 3D magnetic configuration. In this paper we study the energetic ion distribution during combined NBI and 2nd harmonics ICRF heating in LHD using two global simulation codes: a full wave field solver TASK/WK and a drift kinetic equation solver GNET. GNET solves a linearized drift kinetic equation for energetic ions including complicated behavior of trapped particles in 5-D phase space. TASK/WM solves Maxwell's equation for RF wave electric field with complex frequency as a boundary value problem in the 3D magnetic configuration. (author)

  2. Heat supply from nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Stach, V [Ustav Jaderneho Vyzkumu CSKAE, Rez (Czechoslovakia)

    1978-05-01

    The current state of world power production and consumption is assessed. Prognoses made for the years 1980 to 2000 show that nuclear energy should replace the major part of fossil fuels not only in the production of power but also in the production of heat. In this respect high-temperature reactors are highly prospective. The question is discussed of the technical and economic parameters of dual-purpose heat and power plants. It is, however, necessary to solve problems arising from the safe siting of nuclear heat and power plants and their environmental impacts. The economic benefits of combined power and heat production by such nuclear plants is evident.

  3. A comparison of combined heat and power feasibility models

    Energy Technology Data Exchange (ETDEWEB)

    Hinojosa, L.R.; Day, A.R.; Maidment, G.G. [Department of Engineering Systems, Faculty of Engineering, Science and the Built Environment, London South Bank University, 103 Borough Road, London SE1 0AA (United Kingdom); Dunham, C.; Kirk, P. [SEA/RENUE, 42 Braganza Street, London SE17 3RJ (United Kingdom)

    2007-09-15

    Carrying out feasibility studies for combined heat and power (CHP) in buildings systems is one of the most important steps in the decision-making process. This paper compares the features of different software packages available in the market and some custom-built models. It also discusses the advantages and disadvantages of building one's own application. The number of variables that need to be considered will depend on the level of accuracy and flexibility sought. Software packages are a good start, but they tend to be either overly simple or extremely complicated, and sometimes not very flexible. On the other hand, building custom-built generic models that include different technologies, unit sizes, control modes, market restrictions and benefits, can be a complex and laborious process, but will be more transparent to the user. (author)

  4. Heat Stress Effects on Growing-Finishing Swine

    Science.gov (United States)

    Understanding the factors that create heat stress, the response of the animals while under heat stress, and the signs of heat-stressed swine are essential to making rational decisions for the selection, design, and management of their environments. Heat stressors include combinations of environment...

  5. Industrial implementation issues of Total Site Heat Integration

    International Nuclear Information System (INIS)

    Chew, Kew Hong; Klemeš, Jiří Jaromír; Wan Alwi, Sharifah Rafidah; Abdul Manan, Zainuddin

    2013-01-01

    Heat Integration has been a well-established energy conservation strategy in the industry. Total Site Heat Integration (TSHI) has received growing interest since its inception in the 90s. The methodology has been used with certain simplifications to solve TSHI problems. This paper investigates the main issues that can influence the practical implementation of TSHI in the industry. The main aim is to provide an assessment and possible guidance for future development and extension of the TSHI methodology from the industrial perspective. Several key issues have been identified as being of vital importance for the industries: design, operation, reliability/availability/maintenance, regulatory/policy and economics. Design issues to consider include plant layout, pressure drop, etc. For operation, issues such as startup and shutdown need to be considered. Reliability, availability and maintenance (RAM) are important as they directly affect the production. Relevant government policy and incentives are also important when considering the options for TSHI. Finally, a TSHI system needs to be economically viable. This paper highlights the key issues to be considered for a successful implementation of TSHI. The impacts of these issues on TS integration are summarised in a matrix, which forms a basis for an improved and closer-to-real-life implementation of the TSHI methodology. Highlights: ► Current TSHI methodology has been used for solving models with certain simplifications. ► Several issues that can influence practical implementation of TSHI are identified. ► Impacts of these issues on safety, environment and economics are evaluated. ► The findings form a basis for an improved and practical implementation of TSHI

  6. An evaluation of the potential of combination processes involving heat and irradiation for food preservation

    International Nuclear Information System (INIS)

    Shamsuzzaman, K.; Payne, B.; Cole, L.; Goodwin, M.; Borsa, J.

    1989-11-01

    Effects of combined heating and gamma radiation on Clostridium sporogenes spores and Salmonella seftenberg were examined. The order in which irradiation and heat were applied had a profound effect on the survival of the organisms. Heating of C.sporogenes spores at 95 degrees Celsius had very little effect on their sensitivity to subsequent irradiation, but irradiation of the spores at 0 degrees Celsius increased their sensitivity to subsequent heat treatment and thus reduced their heat D 10 values (time required to activate the spores to 10% of their initial number). This radiation-induced heat sensitivity increased with the increase in radiation dose. The Z values (change in temperature required for a tenfold change in D 10 values) of the spores were found to increase with the increase in pre-irradiation dose. Radiation-induced heat sensitivity was found to persist for at least 35 days in spores irradiated in frozen or freeze-dried states in distilled water or in phosphate buffer suspensions, and for at least 14 days in a number of food slurries. In phosphate buffer and nutrient broth suspensions, the radiation-heat synergism decreased with increasing pH of the media from pH 4.7 to pH 7.5. However, the effect of pH on synergism was less pronounced in spores suspended in some food slurries. Preliminary results indicate that pre-irradiation of S. senftenberg at 0.5 kGy did not change the heat sensitivity of this organism at 52 degrees Celsius, but when radiation and heat were applied simultaneously, synergistic inactivation was observed even at 50 degrees Celsius. Practical implications of these results are discussed

  7. Effect of Heat Input on Inclusion Evolution Behavior in Heat-Affected Zone of EH36 Shipbuilding Steel

    Science.gov (United States)

    Sun, Jincheng; Zou, Xiaodong; Matsuura, Hiroyuki; Wang, Cong

    2018-03-01

    The effects of heat input parameters on inclusion and microstructure characteristics have been investigated using welding thermal simulations. Inclusion features from heat-affected zones (HAZs) were profiled. It was found that, under heat input of 120 kJ/cm, Al-Mg-Ti-O-(Mn-S) composite inclusions can act effectively as nucleation sites for acicular ferrites. However, this ability disappears when the heat input is increased to 210 kJ/cm. In addition, confocal scanning laser microscopy (CSLM) was used to document possible inclusion-microstructure interactions, shedding light on how inclusions assist beneficial transformations toward property enhancement.

  8. A Review of Wettability Effect on Boiling Heat Transfer Enhancement

    International Nuclear Information System (INIS)

    Seo, Gwang Hyeok; Jeun, Gyoo Dong; Kim, Sung Joong

    2012-01-01

    Critical heat flux (CHF) and nucleate boiling heat transfer coefficient (NBHTC) are the key parameters characterizing pool boiling heat transfer. These variables are complicatedly related to thermal-hydraulic parameters of surface wettability, nucleation site density, bubble departure diameter and frequency, to mention a few. In essence, wettability effect on pool boiling heat transfer has been a major fuel to enhance the CHF. Often, however, the improved wettability effect hinders the nucleate boiling. Thus a comprehensive review of such wettability effect may enlighten a further study in this boiling heat transfer area. Phan et al. described surface wettability effects on boiling heat transfer

  9. Combined heat and gamma-irradiation treatments for the control of strawberry diseases under market conditions

    International Nuclear Information System (INIS)

    Brodrick, H.T.; Thomas, A.C.; Van Tonder, A.J.; Terblanche, J.C.

    1977-02-01

    The spoilage of strawberries under local market conditions was investigated. It was confirmed that the major losses are due to 'leak' disease caused by Rhizopus stolonifer (Ehr. ex Fr.) Lind. It was also established that further fruit losses in summer are due to anthracnose caused by the fungus Colletotrichum acutatum Simmonds. This is the first time that the latter pathogen has been isolated and identified and recognised as a problem on strawberries in South Africa. Studies with R. stolonifer in culture showed that 46 degrees Celsius for 20 min (the previous international standard heat treatment for fruit) was disappointing, while a treatment at 50 degrees Celsius for 10 min effectively inhibited spore germination. Irradiation studies with cultures of R. stolonifer and C. acutatum showed that a dose of 200 and 100 krad, respectively, resulted in excellent inhibition of spore germination. However, irradiating in nitrogen gas resulted in a tenfold reduction in the effectiveness of the irradiation treatments. The use of nitrogen during irradiation, therefore, cannot be considered, especially where an effective control of the fungal pathogens is desired. Investigations with different cultivars clearly demonstrated the synergistic effect on disease control obtained when combining heat and irradiation treatments. The combination treatment (moist heat at 50-52 degrees Celsius for 10 min plus 200 krad), besides effectively controlling both diseases in strawberries, did not adversely affect berry quality. In simulated transport tests it was shown that a minimal amount of berry softening did occur with this treatment, but this adverse effect was negligible compared with the beneficial effect obtained from disease control. In semi-commercial experiments it was shown that the combination heat and irradiation treatment effectively controlled spoilage diseases for a period of several days from picking, thus allowing sufficient time to market the fruit under local market

  10. Micro-tubular flame-assisted fuel cells for micro-combined heat and power systems

    Science.gov (United States)

    Milcarek, Ryan J.; Wang, Kang; Falkenstein-Smith, Ryan L.; Ahn, Jeongmin

    2016-02-01

    Currently the role of fuel cells in future power generation is being examined, tested and discussed. However, implementing systems is more difficult because of sealing challenges, slow start-up and complex thermal management and fuel processing. A novel furnace system with a flame-assisted fuel cell is proposed that combines the thermal management and fuel processing systems by utilizing fuel-rich combustion. In addition, the flame-assisted fuel cell furnace is a micro-combined heat and power system, which can produce electricity for homes or businesses, providing resilience during power disruption while still providing heat. A micro-tubular solid oxide fuel cell achieves a significant performance of 430 mW cm-2 operating in a model fuel-rich exhaust stream.

  11. Modelling and control synthesis of a micro-combined heat and power interface for a concentrating solar power system in off-grid rural power applications

    Science.gov (United States)

    Prinsloo, Gerro; Dobson, Robert; Brent, Alan; Mammoli, Andrea

    2016-05-01

    Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

  12. Evaluation of the performance of combined cooling, heating, and power systems with dual power generation units

    International Nuclear Information System (INIS)

    Knizley, Alta A.; Mago, Pedro J.; Smith, Amanda D.

    2014-01-01

    The benefits of using a combined cooling, heating, and power system with dual power generation units (D-CCHP) is examined in nine different U.S. locations. One power generation unit (PGU) is operated at base load while the other is operated following the electric load. The waste heat from both PGUs is used for heating and for cooling via an absorption chiller. The D-CCHP configuration is studied for a restaurant benchmark building, and its performance is quantified in terms of operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE). Cost spark spread, PEC spark spread, and CDE spark spread are examined as performance indicators for the D-CCHP system. D-CCHP system performance correlates well with spark spreads, with higher spark spreads signifying greater savings through implementation of a D-CCHP system. A new parameter, thermal difference, is introduced to investigate the relative performance of a D-CCHP system compared to a dual PGU combined heat and power system (D-CHP). Thermal difference, together with spark spread, can explain the variation in savings of a D-CCHP system over a D-CHP system for each location. The effect of carbon credits on operational cost savings with respect to the reference case is shown for selected locations. - Highlights: • We investigate benefits from using combined cooling, heating, and power systems. • A dual power generation unit configuration is considered for CCHP and CHP. • Spark spreads for cost, energy, and emissions correlate with potential savings. • Thermal difference parameter helps to explain variations in potential savings. • Carbon credits may increase cost savings where emissions savings are possible

  13. Studying the effects of combining internal and external heat recovery on techno-economic performances of gas–steam power plants

    International Nuclear Information System (INIS)

    Carapellucci, Roberto; Giordano, Lorena

    2016-01-01

    Highlights: • Effects of gas-cycle regeneration on steam–gas power plants are investigated. • Power plant performances are evaluated varying gas turbine operative parameters. • The power plant operational flexibility is assessed through an off-design analysis. • Gas-cycle regeneration improves energy and economic performance parameters. • Power increase due to regenerator by-pass depends on steam section design. - Abstract: Thermodynamic regeneration is regarded as a conventional technique to enhance the efficiency of gas turbines, by means of an internal recovery of waste heat from exhaust gases. In combined cycle power plants (CCGTs), only external heat recovery is usually applied, in order to achieve the highest steam cycle power. Combining internal and external recovery, while decreasing the power plant rated capacity, has the potential to boost the efficiency of CCGTs. This paper aims to examine the effects of thermodynamic regeneration on steam–gas power plants from the energy and economic point of view. First, a dual pressure combined cycle based on a regenerative gas turbine is designed using GateCycle software and effects on energy and economic performances are evaluated varying gas turbine operating parameters. Then, an off-design simulation of different CCGT configurations is carried out, in order to evaluate the power increase achieved by-passing the regenerator and its effects on efficiency and cost of electricity. The study has shown that the improvement of energy and economic performances of regenerative CCGTs is more and more pronounced with the increase of turbine inlet temperature (TIT). Additionally, regeneration enhances the power plant operational flexibility, allowing to obtain a 30% power increase with respect to the design value, if the regenerator is fully by-passed and the bottoming steam cycle is designed to manage the increased flue gas temperature.

  14. Combined heat and power production planning in a waste-to-energy plant on a short-term basis

    International Nuclear Information System (INIS)

    Touš, Michal; Pavlas, Martin; Putna, Ondřej; Stehlík, Petr; Crha, Lukáš

    2015-01-01

    In many cases, WtE (waste-to-energy) plants are CHP (combined heat and power) producers. They are often integrated into a central heating system and they also export electricity to the grid. Therefore, they have to plan their operation on a long-term basis (months, years) as well as on a short-term basis (hours, days). Simulation models can effectively support decision making in CHP production planning. In general, CHP production planning on a short-term basis is a challenging task for WtE plants. This article presents a simulation based support. It is demonstrated on an example involving a real WtE plant. Most of the models of relevant WtE sub-systems (boilers, steam turbine) are developed using operational data and applying linear regression and artificial neural network technique. The process randomness given mainly by fluctuating heating value of waste leads to uncertainty in a calculation of CHP production and a stochastic approach is appropriate. The models of the sub-systems are, therefore, extended of a stochastic part and Monte-Carlo simulation is applied. Compared to the current planning strategy in the involved WtE plant, the stochastic simulation based planning provides increased CHP production resulting in better net thermal efficiency and increased revenue. This is demonstrated through a comparison using real operational data. - Highlights: • Introduction of a stochastic model of a CHP production in a waste-to-energy plant. • An application of the model for the next day CHP production planning. • Better net thermal efficiency and therefore increased revenue achieved.

  15. A combined power cycle utilizing low-temperature waste heat and LNG cold energy

    International Nuclear Information System (INIS)

    Shi Xiaojun; Che Defu

    2009-01-01

    This paper has proposed a combined power system, in which low-temperature waste heat can be efficiently recovered and cold energy of liquefied natural gas (LNG) can be fully utilized as well. This system consists of an ammonia-water mixture Rankine cycle and an LNG power generation cycle, and it is modelled by considering mass, energy and species balances for every component and thermodynamic analyses are conducted. The results show that the proposed combined cycle has good performance, with net electrical efficiency and exergy efficiency of 33% and 48%, respectively, for a typical operating condition. The power output is equal to 1.25 MWh per kg of ammonia-water mixture. About 0.2 MW of electrical power for operating sea water pumps can be saved. Parametric analyses are performed for the proposed combined cycle to evaluate the effects of key factors on the performance of the proposed combined cycle through simulation calculations. Results show that a maximum net electrical efficiency can be obtained as the inlet pressure of ammonia turbine increases and the peak value increases as the ammonia mass fraction increases. Exergy efficiency goes up with the increased ammonia turbine inlet pressure. With the ammonia mass fraction increases, the net electrical efficiency increases, whereas exergy efficiency decreases. For increasing LNG turbine inlet pressure or heat source temperature, there is also a peak of net electrical efficiency and exergy efficiency. With the increase of LNG gas turbine outlet pressure, exergy efficiency increases while net electrical efficiency drops

  16. Harmony search algorithm for solving combined heat and power economic dispatch problems

    Energy Technology Data Exchange (ETDEWEB)

    Khorram, Esmaile, E-mail: eskhor@aut.ac.i [Department of Applied Mathematics, Faculty of Mathematics and Computer Science, Amirkabir University of Technology, No. 424, Hafez Ave., 15914 Tehran (Iran, Islamic Republic of); Jaberipour, Majid, E-mail: Majid.Jaberipour@gmail.co [Department of Applied Mathematics, Faculty of Mathematics and Computer Science, Amirkabir University of Technology, No. 424, Hafez Ave., 15914 Tehran (Iran, Islamic Republic of)

    2011-02-15

    Economic dispatch (ED) is one of the key optimization problems in electric power system operation. The problem grows complex if one or more units produce both power and heat. Combined heat and power economic dispatch (CHPED) problem is a complicated problem that needs powerful methods to solve. This paper presents a harmony search (EDHS) algorithm to solve CHPED. Some standard examples are presented to demonstrate the effectiveness of this algorithm in obtaining the optimal solution. In all cases, the solutions obtained using EDHS algorithm are better than those obtained by other methods.

  17. Application of combined heat and power in Malaysia Industrial Sector

    International Nuclear Information System (INIS)

    Zaredah Hashim; Faridah Mohd Taha

    2010-01-01

    Malaysia is still working on continuing its economic growth especially in the industrial sector in order to achieve vision 2020. The rapid industrialization process has caused increment in the energy demand, which simultaneously increases carbon dioxide (CO 2 ) emissions. Energy efficient technologies are strongly needed for reducing the energy requirement and to avoid the depleting of energy resources. This project focused on the application of integrated resource planning (IRP) in industrial sector using Combined Heat and Power (CHP), as a strategy for Demand Side Management (DSM). This approach is another way for meeting near and future energy requirement in Malaysia's industrial sector. Two scenarios which are Business As Usual (BAU) and CHP were developed using End Use Model EUM), to forecast the energy demand and CO 2 emission in Malaysia's industries. The effectiveness of the proposed method is then simulated using Long Range Energy Alternative Planning System (LEAP) software and Comparative Model for Projects of Engineering Economics and Energy Environmental Development (COMPEED) analysis. Evaluations were based on the potential of energy saving and CO 2 reduction. Scope of research was limited to pulp and paper industrial sub sector. The research data were extracted from Energy Audit Reports conducted by Malaysia Energy Center (PTM). An engineering calculation was demonstrated. Two designs of CHP applications for the pulp and paper industrial sector are according to heating and electricity sizing. It was found that the most energy efficient and CO 2 reduction for Malaysia's industrial sector is the CHP based on heating requirement. The method was found to be able of save fuel and GHG emission compared to the reference case. (author)

  18. Network Simulation solution of free convective flow from a vertical cone with combined effect of non- uniform surface heat flux and heat generation or absorption

    Science.gov (United States)

    Immanuel, Y.; Pullepu, Bapuji; Sambath, P.

    2018-04-01

    A two dimensional mathematical model is formulated for the transitive laminar free convective, incompressible viscous fluid flow over vertical cone with variable surface heat flux combined with the effects of heat generation and absorption is considered . using a powerful computational method based on thermoelectric analogy called Network Simulation Method (NSM0, the solutions of governing nondimensionl coupled, unsteady and nonlinear partial differential conservation equations of the flow that are obtained. The numerical technique is always stable and convergent which establish high efficiency and accuracy by employing network simulator computer code Pspice. The effects of velocity and temperature profiles have been analyzed for various factors, namely Prandtl number Pr, heat flux power law exponent n and heat generation/absorption parameter Δ are analyzed graphically.

  19. Nuclear district heating

    International Nuclear Information System (INIS)

    Ricateau, P.

    1976-01-01

    An economic study of nuclear district heating is concerned with: heat production, its transmission towards the area to be served and the distribution management towards the consumers. Foreign and French assessments show that the high cost of now existing techniques of hot water transport defines the competing limit distance between the site and township to be below some fifty kilometers for the most important townships (provided that the fuel price remain stationary). All studies converge towards the choice of a high transport temperature as soon as the distance is of some twenty kilometers. As for fossile energy saving, some new possibilities appear with process heat reactors; either PWR of about 1000MWth for large townships, or pool-type reactors of about 100MWth when a combination with an industrial steam supply occurs [fr

  20. Effects of the generator and evaporator temperature differences on a double absorption heat transformer—Different control strategies on utilizing heat sources

    International Nuclear Information System (INIS)

    Wang, Hanzhi; Li, Huashan; Bu, Xianbiao; Wang, Lingbao

    2017-01-01

    Highlights: • Effects of the GETD on the DAHT system performance are analyzed. • Three different configurations are compared in detail. • Suggestions on the heat source control strategies are given. - Abstract: The combination of the absorption heat transformer with renewable energy systems, like solar thermal systems, is raising more and more concern. In those combined systems the strategies on utilizing heat sources can affect system thermodynamic performance significantly. Therefore, this study presents a detailed analysis on the effect of the heat source temperature and different heat source flow patterns on the performance of a double absorption heat transformer (DAHT). A detailed comparative study is carried out to clarify the impact of the generator and evaporator temperature differences (GETD) on the coefficient of performance (COP), exergy efficient (ECOP), exergy destruction rates in the individual components and heat transfer areas needed for each component. The results show that the generator, condenser and absorber-evaporator are responsible for most of the exergy destruction rate in the DAHT system; the parallel-flow configuration (the generator temperature is equal to the evaporator temperature) performs better under the high gross temperature lift conditions; in the case of the counter-flow configuration (the generator temperature is relatively higher), better performance can be obtained in both the COP and ECOP under the proper heat source temperature (85 and 95 °C); the fair-flow configuration (higher temperature in the evaporator) is not recommended in this paper due to no advantages found in either thermodynamic performance or system size.

  1. Modulation of Antioxidant Defense System Is Associated with Combined Drought and Heat Stress Tolerance in Citrus.

    Science.gov (United States)

    Zandalinas, Sara I; Balfagón, Damián; Arbona, Vicent; Gómez-Cadenas, Aurelio

    2017-01-01

    Drought and high temperatures are two major abiotic stress factors that often occur simultaneously in nature, affecting negatively crop performance and yield. Moreover, these environmental challenges induce oxidative stress in plants through the production of reactive oxygen species (ROS). Carrizo citrange and Cleopatra mandarin are two citrus genotypes with contrasting ability to cope with the combination of drought and heat stress. In this work, a direct relationship between an increased antioxidant activity and stress tolerance is reported. According to our results, the ability of Carrizo plants to efficiently coordinate superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR) activities involved in ROS detoxification along with the maintenance of a favorable GSH/GSSG ratio could be related to their relative tolerance to this stress combination. On the other hand, the increment of SOD activity and the inefficient GR activation along with the lack of CAT and APX activities in Cleopatra plants in response to the combination of drought and heat stress, could contribute to an increased oxidative stress and the higher sensibility of this citrus genotype to this stress combination.

  2. Simulation study of soil water and heat dynamics at two sites with significant preferential flow

    Science.gov (United States)

    Votrubova, J.; Vogel, T.; Dohnal, M.; Tesar, M.

    2012-04-01

    Numerical models based on two hydraulically contrasting flow domains coupled through a simple transfer formula have become a useful tool for modeling both water flow and associated substance transport in structured soils. A comparative numerical study focused on the preferential flow effects on the soil heat transport is presented. Sites located in two different headwater catchments were included. Experimental catchment Liz is situated in a forested mountain area of Sumava Mts. in the southern part of the Czech Republic (altitude: 830 m, mean annual temperature: 6.3°C, mean annual precipitation: 861 mm). Uhlirska catchment is located in the north-west of the Czech Republic in Jizera Mts. and is currently undergoing reforestation (altitude: 820 m, mean annual temperature: 4.6°C, mean annual precipitation: 1400 mm). Both sites are instrumented for monitoring of the relevant meteorological and hydrological variables, as well as the soil moisture and temperature distribution. Changes of the soil water content and temperature during vegetation season were simulated. Model performance was qualitatively evaluated and shown to replicate the field measurements. The soils' heat budgets and the preferential flow effect thereon was compared and analyzed.

  3. Power contracting between two different partners. Biogas combined heat and power plants; Energie-Contracting zweier unterschiedlicher Partner. Biogas-Blockheizkraftwerk

    Energy Technology Data Exchange (ETDEWEB)

    Lennartz, Marc Wilhelm

    2013-06-15

    An agricultural consortium in the Eifel (Federal Republic of Germany) has adopted a comprehensive supply of a 7,000 m{sup 2} comprising hotel complex with combined heat and power. The old oil-fired central heating plant has been replaced by a biogas-powered combined heat and power plant (CHP). The hotel was directly connected to the CHP plant by means of a new, approximately 300 m long local heating network including buffer storage. Overall, the hotel operator saves approximately 300,000 L of heating oil annually. The energy demand of the hotel operator will be covered by more than 90 % by means of CHP plants. Thus 20 % of the heating costs is saved.

  4. Combined Heat and Power Market Potential for Opportunity Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Jones, David [Resource Dynamics Corporation, McLean, VA (United States); Lemar, Paul [Resource Dynamics Corporation, McLean, VA (United States

    2015-12-01

    This report estimates the potential for opportunity fuel combined heat and power (CHP) applications in the United States, and provides estimates for the technical and economic market potential compared to those included in an earlier report. An opportunity fuel is any type of fuel that is not widely used when compared to traditional fossil fuels. Opportunity fuels primarily consist of biomass fuels, industrial waste products and fossil fuel derivatives. These fuels have the potential to be an economically viable source of power generation in various CHP applications.

  5. Combined Effect of Gamma Irradiation and Heat Treatment on Microflora of Spices

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, I.; Farkas, J. [Central Food Research Institute, Budapest (Hungary)

    1981-09-15

    The radiation sensitivity of the aerobic bacterial flora was similar both in the ground paprika and the whole black pepper (D{sub 10} values calculated from the exponential survival curves were 1.44 and 1.29 kGy, respectively). The survival rates of the microflora of non-irradiated samples were compared with those of the 1.6-4 kGy irradiated samples as a function of the heating time at various temperature levels, applied to aqueous suspensions of spices. The mesophilic aerobic bacterial flora of black pepper proved to be more heat-resistant than that of paprika powder. The heat resistance of the surviving microflora of irradiated spices was significantly decreased. The heat sensitization effect tended to increase as the radiation dose increased. The heat sensitization by irradiation was greater in the case of the more heat resistant microflora of black pepper. The heat sensitization quotient at 90 Degree-Sign C (i.e. the ratio of the 90% destruction time for unirradiated versus irradiated samples) was approximately 4 for paprika and 9 for black pepper at the 4-kGy dose level. (author)

  6. Combined effect of gamma irradiation and heat treatment on microflora of spices

    International Nuclear Information System (INIS)

    Kiss, I.; Farkas, J.

    1981-01-01

    The radiation sensitivity of the aerobic bacterial flora was similar both in the ground paprika and the whole black pepper (D 10 values calculated from the exponential survival curves were 1.44 and 1.29 kGy, respectively). The survival rates of the microflora of non-irradiated samples were compared with those of the 1.6-4 kGy irradiated samples as a function of the heating time at various temperature levels, applied to aqueous suspensions of spices. The mesophilic aerobic bacterial flora of black pepper proved to be more heat-resistant than that of paprika powder. The heat resistance of the surviving microflora of irradiated spices was significantly decreased. The heat sensitization effect tended to increase as the radiation dose increased. The heat sensitization by irradiation was greater in the case of the more heat-resistant microflora of black pepper. The heat sensitization quotient at 90 0 C (i.e. the ratio of the 90% destruction time for unirradiated versus irradiated samples) was approximately 4 for paprika and 9 for black pepper at the 4-kGy dose level. (author)

  7. Optimal Energy Management of Combined Cooling, Heat and Power in Different Demand Type Buildings Considering Seasonal Demand Variations

    Directory of Open Access Journals (Sweden)

    Akhtar Hussain

    2017-06-01

    Full Text Available In this paper, an optimal energy management strategy for a cooperative multi-microgrid system with combined cooling, heat and power (CCHP is proposed and has been verified for a test case of building microgrids (BMGs. Three different demand types of buildings are considered and the BMGs are assumed to be equipped with their own combined heat and power (CHP generators. In addition, the BMGs are also connected to an external energy network (EEN, which contains a large CHP, an adsorption chiller (ADC, a thermal storage tank, and an electric heat pump (EHP. By trading the excess electricity and heat energy with the utility grid and EEN, each BMG can fulfill its energy demands. Seasonal energy demand variations have been evaluated by selecting a representative day for the two extreme seasons (summer and winter of the year, among the real profiles of year-round data on electricity, heating, and cooling usage of all the three selected buildings. Especially, the thermal energy management aspect is emphasized where, bi-lateral heat trading between the energy supplier and the consumers, so-called energy prosumer concept, has been realized. An optimization model based on mixed integer linear programming has been developed for minimizing the daily operation cost of the EEN while fulfilling the energy demands of the BMGs. Simulation results have demonstrated the effectiveness of the proposed strategy.

  8. Study on diverse passive decay heat removal approach

    International Nuclear Information System (INIS)

    Lin Qian; Si Shengyi

    2012-01-01

    One of the most important principles for nuclear safety is the decay heat removal in accidents. Passive decay heat removal systems are extremely helpful to enhance the safety. In currently design of many advanced nuclear reactors, kinds of passive systems are proposed or developed, such as the passive residual heat removal system, passive injection system, passive containment cooling system. These systems provide entire passive heat removal paths from core to ultimate heat sink. Various kinds of passive systems for decay heat removal are summarized; their common features or differences on heat removal paths and design principle are analyzed. It is found that, these passive decay heat removal paths are similarly common on and connected by several basic heat transfer modes and steps. By the combinations or connections of basic modes and steps, new passive decay heat removal approach or diverse system can be proposed. (authors)

  9. Heat and power from combustibles

    International Nuclear Information System (INIS)

    Zogg, M.

    2002-01-01

    This article compares four ways of generating heat and power from liquid and gaseous fuels. Various combinations of conventional boilers, heat pumps, combined heat and power units and combined-cycle power plants are considered and the ratio of heat to electrical power produced is discussed. Fuel requirements for the four combinations are looked at and net emissions of carbon dioxide, oxides of nitrogen and carbon monoxide presented in graphical form. The author makes recommendations on the choice of the technology to be used to generate heat and electricity for different heat/power ratios and criticises the all too slack emission limits for small combined heat and power units

  10. Combined Heat Transfer in High-Porosity High-Temperature Fibrous Insulations: Theory and Experimental Validation

    Science.gov (United States)

    Daryabeigi, Kamran; Cunnington, George R.; Miller, Steve D.; Knutson, Jeffry R.

    2010-01-01

    Combined radiation and conduction heat transfer through various high-temperature, high-porosity, unbonded (loose) fibrous insulations was modeled based on first principles. The diffusion approximation was used for modeling the radiation component of heat transfer in the optically thick insulations. The relevant parameters needed for the heat transfer model were derived from experimental data. Semi-empirical formulations were used to model the solid conduction contribution of heat transfer in fibrous insulations with the relevant parameters inferred from thermal conductivity measurements at cryogenic temperatures in a vacuum. The specific extinction coefficient for radiation heat transfer was obtained from high-temperature steady-state thermal measurements with large temperature gradients maintained across the sample thickness in a vacuum. Standard gas conduction modeling was used in the heat transfer formulation. This heat transfer modeling methodology was applied to silica, two types of alumina, and a zirconia-based fibrous insulation, and to a variation of opacified fibrous insulation (OFI). OFI is a class of insulations manufactured by embedding efficient ceramic opacifiers in various unbonded fibrous insulations to significantly attenuate the radiation component of heat transfer. The heat transfer modeling methodology was validated by comparison with more rigorous analytical solutions and with standard thermal conductivity measurements. The validated heat transfer model is applicable to various densities of these high-porosity insulations as long as the fiber properties are the same (index of refraction, size distribution, orientation, and length). Furthermore, the heat transfer data for these insulations can be obtained at any static pressure in any working gas environment without the need to perform tests in various gases at various pressures.

  11. Modelling of combined ICRF and NBI heating in JET hybrid plasmas

    Directory of Open Access Journals (Sweden)

    Gallart Dani

    2017-01-01

    Full Text Available During the 2015-2016 JET campaigns many efforts have been devoted to the exploration of high performance plasma scenarios envisaged for ITER operation. In this paper we model the combined ICRF+NBI heating in selected key hybrid discharges using PION. The antenna frequency was tuned to match the cyclotron frequency of minority hydrogen (H at the center of the tokamak coinciding with the second harmonic cyclotron resonance of deuterium. The modelling takes into account the synergy between ICRF and NBI heating through the second harmonic cyclotron resonance of deuterium beam ions which allows us to assess its impact on the neutron rate RNT. We evaluate the influence of H concentration which was varied in different discharges in order to test their role in the heating performance. According to our modelling, the ICRF enhancement of RNT increases by decreasing the H concentration which increases the ICRF power absorbed by deuterons. We find that in the recent hybrid discharges this ICRF enhancement was in the range of 10-25%. Finally, we extrapolate the results to D-T and find that the best performing hybrid discharges correspond to an equivalent fusion power of ∼7.0 MW in D-T.

  12. Solar heat storages in district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This report gives information on the work carried out and the results obtained in Denmark on storages for large solar heating plants in district heating networks. Especially in Denmark the share of district heating has increased to a large percentage. In 1981 around 33% of all dwellings in DK were connected to a district heating network, while the percentage in 2006 was about 60% (in total 1.5 mio. dwellings). In the report storage types for short term storage and long term storages are described. Short term storages are done as steel tanks and is well established technology widely used in district heating networks. Long term storages are experimental and used in connection with solar heating. A number of solar heating plants have been established with either short term or long term storages showing economy competitive with normal energy sources. Since, in the majority of the Danish district heating networks the heat is produced in co-generation plants, i.e. plants producing both electricity and heat for the network, special attention has been put on the use of solar energy in combination with co-generation. Part of this report describes that in the liberalized electricity market central solar heating plants can also be advantageous in combination with co-generation plants. (au)

  13. Putney Basketville Site Biomass CHP Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hunsberger, Randolph [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mosey, Gail [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2013-10-01

    The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response Center for Program Analysis developed the RE-Powering America's Land initiative to reuse contaminated sites for renewable energy generation when aligned with the community's vision for the site. The Putney, Vermont, Basketville site, formerly the location of a basket-making facility and a paper mill andwoolen mill, was selected for a feasibility study under the program. Biomass was chosen as the renewable energy resource based on abundant woody-biomass resources available in the area. Biomass combined heat and power (CHP) was selected as the technology due to nearby loads, including Putney Paper and Landmark College.

  14. System design package for the solar heating and cooling central data processing system

    Science.gov (United States)

    1978-01-01

    The central data processing system provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications. Overall software system requirements were established for use in the central integration facility which transforms raw data collected at remote sites into performance evaluation information for assessing the performance of solar heating and cooling systems.

  15. Higher Temperature at Lower Elevation Sites Fails to Promote Acclimation or Adaptation to Heat Stress During Pollen Germination

    Directory of Open Access Journals (Sweden)

    Lluvia Flores-Rentería

    2018-04-01

    Full Text Available High temperatures associated with climate change are expected to be detrimental for aspects of plant reproduction, such as pollen viability. We hypothesized that (1 higher peak temperatures predicted with climate change would have a minimal effect on pollen viability, while high temperatures during pollen germination would negatively affect pollen viability, (2 high temperatures during pollen dispersal would facilitate acclimation to high temperatures during pollen germination, and (3 pollen from populations at sites with warmer average temperatures would be better adapted to high temperature peaks. We tested these hypotheses in Pinus edulis, a species with demonstrated sensitivity to climate change, using populations along an elevational gradient. We tested for acclimation to high temperatures by measuring pollen viability during dispersal and germination stages in pollen subjected to 30, 35, and 40°C in a factorial design. We also characterized pollen phenology and measured pollen heat tolerance using trees from nine sites along a 200 m elevational gradient that varied 4°C in temperature. We demonstrated that this gradient is biologically meaningful by evaluating variation in vegetation composition and P. edulis performance. Male reproduction was negatively affected by high temperatures, with stronger effects during pollen germination than pollen dispersal. Populations along the elevational gradient varied in pollen phenology, vegetation composition, plant water stress, nutrient availability, and plant growth. In contrast to our hypothesis, pollen viability was highest in pinyons from mid-elevation sites rather than from lower elevation sites. We found no evidence of acclimation or adaptation of pollen to high temperatures. Maximal plant performance as measured by growth did not occur at the same elevation as maximal pollen viability. These results indicate that periods of high temperature negatively affected sexual reproduction, such that

  16. Sensitivities Affecting Heat and Urban Heat Island Effect on Local Scale Projected to Neighborhood Scale in Baltimore, Maryland

    Science.gov (United States)

    Sze, C.; Zaitchik, B. F.; Scott, A.

    2015-12-01

    Urban regions are often impacted more by heat than adjacent rural areas, which is a phenomenon known as the urban heat island (UHI) effect. Urban areas are also highly heterogeneous and notoriously difficult to monitor using standard meteorological protocols—the hottest microclimates within a city often occur in locations that lack open, representative installation sites that are an adequate distance from buildings and direct heat sources. To investigate the challenges of monitoring urban heat, this study examines the sensitivity of temperature and humidity sensors currently used in a Baltimore UHI monitoring network to differences in sun exposure, material on which the data collecting instrument is attached, and land cover class of the vicinity. Sensitivity to sun exposure and attachment site can be interpreted as sources of uncertainty for urban heat monitoring, while sensitivity to land cover may reflect a true source of local temperature and humidity variability. In this study, we present results from a test deployment designed to assess the sensitivity of heat measurements to each of these three factors. We then apply these results to interpret measurements taken across the entire Baltimore UHI monitoring network. These results can then be used to improve heat measurements and more accurately represent and quantify the UHI effect on a broader scale, such as in neighborhoods or urban centers.

  17. Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

    Energy Technology Data Exchange (ETDEWEB)

    Stenerl& #246; w, Bo; Karlsson, Karin H.; Radulescu, Irina; Rydberg, Bjorn; Stenerlow, Bo

    2008-04-29

    Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel electrophoresis (PFGE) are in fact due to heat-labile sites (HLS) within clustered lesions, thus reflecting an artifact of preparation of genomic DNA at elevated temperature. To further characterize the influence of HLS on DSB induction and repair, four human cell lines (GM5758, GM7166, M059K, U-1810) with apparently normal DSB rejoining were tested for bi-phasic rejoining after gamma irradiation. When heat-released DSBs were excluded from the measurements the fraction of fast rejoining decreased to less than 50% of the total. However, neither the half-times of the fast (t{sub 1/2} = 7-8 min) or slow (t{sub 1/2} = 2.5 h) DSB rejoining were changed significantly. At t=0 the heat-released DSBs accounted for almost 40% of the DSBs, corresponding to 10 extra DSB/cell/Gy in the initial DSB yield. These heat-released DSBs were repaired within 60-90 min in all tested cells, including M059K cells treated with wortmannin or DNA-PKcs defect M059J cells. Furthermore, cells lacking XRCC1 or Poly(ADP-ribose) polymerase-1 (PARP-1) rejoined both total DSBs and heat-released DSBs similar to normal cells. In summary, the presence of heat-labile sites have a substantial impact on DSB induction yields and DSB rejoining rates measured by pulsed-field gel electrophoresis, and HLS repair is independent of DNA-PKcs, XRCC1 and PARP.

  18. A detailed study of heat flow at the Fifth Water Site, Utah, in the Basin and Range-Colorado Plateaus transition

    Science.gov (United States)

    Powell, William G.; Chapman, David S.

    1990-05-01

    A detailed heat flow study has been conducted at a site in the southern Wasatch Mountains, Utah, in the thermal transition between the Colorado Plateau and Basin and Range tectonic provinces of the western U.S.A. Two wells, 600 m deep and only 400 m apart, in rugged terrain provided constraints on topographic and microclimatic effects and helped demonstrate the efficacy but also some inadequacies of commonly used heat flow corrections. Microclimatic effects changed the subsurface thermal gradients by up to 6%; atmospheric temperature lapse, insolation and vegetation all contribute about equally to the subsurface effects. The topographic disturbance decreased gradients by as much as 25%. Paleoclimate effects may decrease the heat flow by 7%, but the local paleoclimate is not well constrained and this value is uncertain. The rate of erosion in the Wasatch Mountains is also very poorly known, but is an important influence on the borehole temperature measurements. For reasonable bounds on the erosion rate of 0.1-1.0 mm y -1, acting over the past 10-20 My, the erosional history of the Wasatch Mountains contributes from 10% to 50% of the observed heat flow; lower values are more probable. The heat flow at Fifth Water is greater than 90 mW m -2, and possibly as high as 210 mW m -2, depending upon the paleoclimatic and erosional scenarios assumed. Our preferred value of corrected heat flow is 150 ± 10 mWm -2. This value is significantly higher than nearby heat flow determinations in both the Colorado Plateau and Basin and Range provinces, although well within the range of all Basin and Range heat flow estimates. Cooling of magma bodies in the upper crust and upwelling groundwater are unlikely mechanisms for the elevated heat flow at this site.

  19. Residential on site solar heating systems: a project evaluation using the capital asset pricing model

    Energy Technology Data Exchange (ETDEWEB)

    Schutz, S.R.

    1978-12-01

    An energy source ready for immediate use on a commercial scale is solar energy in the form of On Site Solar Heating (OSSH) systems. These systems collect solar energy with rooftop panels, store excess energy in water storage tanks and can, in certain circumstances, provide 100% of the space heating and hot water required by the occupants of the residential or commercial structure on which the system is located. Such systems would take advantage of a free and inexhaustible energy source--sunlight. The principal drawback of such systems is the high initial capital cost. The solution would normally be a carefully worked out corporate financing plan. However, at the moment it is individual homeowners and not corporations who are attempting to finance these systems. As a result, the terms of finance are excessively stringent and constitute the main obstacle to the large scale market penetration of OSSH. This study analyzes the feasibility of OSSH as a private utility investment. Such systems would be installed and owned by private utilities and would displace other investment projects, principally electric generating plants. The return on OSSH is calculated on the basis of the cost to the consumer of the equivalent amount of electrical energy that is displaced by the OSSH system. The hurdle rate for investment in OSSH is calculated using the Sharpe--Lintner Capital Asset Pricing Model. The results of this study indicate that OSSH is a low risk investment having an appropriate hurdle rate of 7.9%. At this rate, OSSH investment appears marginally acceptable in northern California and unambiguously acceptable in southern California. The results also suggest that utility investment in OSSH should lead to a higher degree of financial leverage for utility companies without a concurrent deterioration in the risk class of utility equity.

  20. Dynamic modeling and evaluation of solid oxide fuel cell - combined heat and power system operating strategies

    Science.gov (United States)

    Nanaeda, Kimihiro; Mueller, Fabian; Brouwer, Jacob; Samuelsen, Scott

    Operating strategies of solid oxide fuel cell (SOFC) combined heat and power (CHP) systems are developed and evaluated from a utility, and end-user perspective using a fully integrated SOFC-CHP system dynamic model that resolves the physical states, thermal integration and overall efficiency of the system. The model can be modified for any SOFC-CHP system, but the present analysis is applied to a hotel in southern California based on measured electric and heating loads. Analysis indicates that combined heat and power systems can be operated to benefit both the end-users and the utility, providing more efficient electric generation as well as grid ancillary services, namely dispatchable urban power. Design and operating strategies considered in the paper include optimal sizing of the fuel cell, thermal energy storage to dispatch heat, and operating the fuel cell to provide flexible grid power. Analysis results indicate that with a 13.1% average increase in price-of-electricity (POE), the system can provide the grid with a 50% operating range of dispatchable urban power at an overall thermal efficiency of 80%. This grid-support operating mode increases the operational flexibility of the SOFC-CHP system, which may make the technology an important utility asset for accommodating the increased penetration of intermittent renewable power.

  1. Risk benefit analysis of site alternatives for a nuclear power plant producing both electricity and district heat

    International Nuclear Information System (INIS)

    Savolainen, I.; Vuori, S.

    1978-01-01

    The environmental impacts due to radioactive releases in normal operation and accidents are primarily assessed for each site as also the district heat transmission costs. Secondarily the risk components are converted to a compatible form, expressed in monetary units, and compared directly to district heat transmission costs. Annual savings from the shortening of the district heat transmission line are clearly larger than the monetary value given to the expectation of the increased risk. (author)

  2. Combining Lactic Acid Spray with Near-Infrared Radiation Heating To Inactivate Salmonella enterica Serovar Enteritidis on Almond and Pine Nut Kernels.

    Science.gov (United States)

    Ha, Jae-Won; Kang, Dong-Hyun

    2015-07-01

    The aim of this study was to investigate the efficacy of near-infrared radiation (NIR) heating combined with lactic acid (LA) sprays for inactivating Salmonella enterica serovar Enteritidis on almond and pine nut kernels and to elucidate the mechanisms of the lethal effect of the NIR-LA combined treatment. Also, the effect of the combination treatment on product quality was determined. Separately prepared S. Enteritidis phage type (PT) 30 and non-PT 30 S. Enteritidis cocktails were inoculated onto almond and pine nut kernels, respectively, followed by treatments with NIR or 2% LA spray alone, NIR with distilled water spray (NIR-DW), and NIR with 2% LA spray (NIR-LA). Although surface temperatures of nuts treated with NIR were higher than those subjected to NIR-DW or NIR-LA treatment, more S. Enteritidis survived after NIR treatment alone. The effectiveness of NIR-DW and NIR-LA was similar, but significantly more sublethally injured cells were recovered from NIR-DW-treated samples. We confirmed that the enhanced bactericidal effect of the NIR-LA combination may not be attributable to cell membrane damage per se. NIR heat treatment might allow S. Enteritidis cells to become permeable to applied LA solution. The NIR-LA treatment (5 min) did not significantly (P > 0.05) cause changes in the lipid peroxidation parameters, total phenolic contents, color values, moisture contents, and sensory attributes of nut kernels. Given the results of the present study, NIR-LA treatment may be a potential intervention for controlling food-borne pathogens on nut kernel products. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  3. Convective heat transfer enhancement using Carbon nanofibers (CNFs): influence of amorphous carbon layer on heat transfer performance

    NARCIS (Netherlands)

    Taha, T.J.; Lefferts, Leonardus; van der Meer, Theodorus H.

    2013-01-01

    In this work, an experimental heat transfer investigation was carried out to investigate the combined influence of both amorphous carbon (a-C) layer thickness and carbon nanofibers (CNFs) on the convective heat transfer behavior. Synthesis of these carbon nano structures was achieved using catalytic

  4. Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

    Directory of Open Access Journals (Sweden)

    Oriol Gonzalez

    2016-10-01

    Full Text Available We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.g., 100 °C together with pulsed UV light irradiation employing a commercially available, 325 nm UV diode (square, 1 min period, 15 mA drive current signal, results in an up to 80-fold enhancement in sensitivity to nitrogen dioxide. Furthermore, this combined operation method allows for making savings in power consumption that range from 35% to over 80%. These results are achieved by exploiting the dynamics of sensor response under pulsed UV light, which convey important information for the quantitative analysis of nitrogen dioxide.

  5. Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra.

    Science.gov (United States)

    Gonzalez, Oriol; Roso, Sergio; Vilanova, Xavier; Llobet, Eduard

    2016-01-01

    We report on the use of combined heating and pulsed UV light activation of indium oxide gas sensors for enhancing their performance in the detection of nitrogen dioxide in air. Indium oxide nano-octahedra were synthesized at high temperature (900 °C) via vapour-phase transport and screen-printed onto alumina transducers that comprised interdigitated electrodes and a heating resistor. Compared to the standard, constant temperature operation of the sensor, mild heating (e.g., 100 °C) together with pulsed UV light irradiation employing a commercially available, 325 nm UV diode (square, 1 min period, 15 mA drive current signal), results in an up to 80-fold enhancement in sensitivity to nitrogen dioxide. Furthermore, this combined operation method allows for making savings in power consumption that range from 35% to over 80%. These results are achieved by exploiting the dynamics of sensor response under pulsed UV light, which convey important information for the quantitative analysis of nitrogen dioxide.

  6. Two-stage absorber systems - Economically viable combined heat and cold generation; Wirtschaftlicher Kraft-Waerme-Kaelte-Verbund

    Energy Technology Data Exchange (ETDEWEB)

    Biniossek, H. [Giesecke und Devrient, Muenchen (Germany); Schmid, W. [Technische Gebaeudeausruestung, Muenchen (Germany)

    2008-07-01

    This article takes a look at how the possibilities of optimising power, heat and cold generation for the German Giesecke and Devrient company were examined and implemented. The company, which produces banknotes and chip-cards, chose the combination of a Combined Heat and Power (CHP) Unit and a two-stage absorber refrigeration system. The company's old system is briefly described and the reasons for replacing it are discussed. The careful dimensioning of the new system and the search for appropriate equipment are described. Intelligent power flows and a cooling system with two different temperature levels are described. Costs saved and emergency power generation are also looked at, as are the complex demands placed on the control of the system. The system's functioning is briefly described.

  7. Sustainable renewable energy seawater desalination using combined-cycle solar and geothermal heat sources

    KAUST Repository

    Missimer, Thomas M.

    2013-01-01

    Key goals in the improvement of desalination technology are to reduce overall energy consumption, make the process "greener," and reduce the cost of the delivered water. Adsorption desalination (AD) is a promising new technology that has great potential to reduce the need for conventional power, to use solely renewable energy sources, and to reduce the overall cost of water treatment. This technology can desalt seawater or water of even higher salinity using waste heat, solar heat, or geothermal heat. An AD system can operate effectively at temperatures ranging from 55 to 80 °C with perhaps an optimal temperature of 80 °C. The generally low temperature requirement for the feedwater allows the system to operate quite efficiently using an alternative energy source, such as solar power. Solar power, particularly in warm dry regions, can generate a consistent water temperature of about 90 °C. Although this temperature is more than adequate to run the system, solar energy collection only can occur during daylight hours, thereby necessitating the use of heat storage during nighttime or very cloudy days. With increasing capacity, the need for extensive thermal storage may be problematic and could add substantial cost to the development of an AD system. However, in many parts of the world, there are subsurface geothermal energy sources that have not been extensively used. Combining a low to moderate geothermal energy recovery system to an AD system would provide a solution to the thermal storage issue. However, geothermal energy development from particularly Hot Dry Rock is limited by the magnitude of the heat flow required for the process and the thermal conductivity of the rock material forming the heat reservoir. Combining solar and geothermal energy using an alternating 12-h cycle would reduce the probability of depleting the heat source within the geothermal reservoir and provide the most effective use of renewable energy. © 2013 Desalination Publications.

  8. High power plasma heating experiments on the Proto-MPEX facility

    Science.gov (United States)

    Bigelow, T. S.; Beers, C. J.; Biewer, T. M.; Caneses, J. F.; Caughman, J. B. O.; Diem, S. J.; Goulding, R. H.; Green, D. L.; Kafle, N.; Rapp, J.; Showers, M. A.

    2017-10-01

    Work is underway to maximize the power delivered to the plasma that is available from heating sources installed on the Prototype Materials Plasma Exposure eXperiment (Proto-MPEX) at ORNL. Proto-MPEX is a linear device that has a >100 kW, 13.56 MHz helicon plasma generator available and is intended for material sample exposure to plasmas. Additional plasma heating systems include a 10 kW 18 GHz electron cyclotron heating (ECH) system, a 25 kW 8 MHz ion cyclotron heating ICH system, and a 200 kW 28 GHz electron Bernstein wave (EBW) and ECH system. Most of the heating systems have relatively good power transmission efficiency, however, the 28 GHz EBW system has a lower efficiency owing to stringent requirements on the microwave launch characteristics for EBW coupling combined with the lower output mode purity of the early-model gyrotron in use and its compact mode converter system. A goal for the Proto-MPEX is to have a combined heating power of 200 kW injected into the plasma. Infrared emission diagnostics of the target plate combined with Thomson Scattering, Langmuir probe, and energy analyzer measurements near the target are utilized to characterize the plasmas and coupling efficiency of the heating systems. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC-05-00OR22725.

  9. Combined use of solar heat and cogeneration - a perspective for district heating?; Kombinierter Einsatz von solarer Waerme und Kraft-Waerme-Kopplung - eine Perspektive fuer die Nahwaerme?

    Energy Technology Data Exchange (ETDEWEB)

    Entress, J. [Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Stuttgart (Germany). Abt. Systemanalyse und Technikbewertung; Steinborn, F. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany). Fachgebiet Systemanalyse

    1998-02-01

    With Cogeneration of Heat and Power (CHP), climate-endangering CO{sub 2}-emissions can be reduced singificantly. The heat produced can be delivered at prices comparable to those of conventionally produced heat. With solar district heating, yet higher CO{sub 2}-savings are possible but at higher cost. Promising is a combination of CHP and solar district heating: The heat storage of the solar system can be used to level out heat demand, leading to smooth CHP operation, while heat generated by CHP can be used to substitute for low irradiation during the winter period. However, calculations together with simulation and optimization indicate that combining CHP and solar district heating is not the optimal solution in all cases. (orig.) [Deutsch] Der Einsatz von Blockheizkraftwerken (BHKW) kann zu einer deutlichen Reduzierung der klimagefaehrdenden CO{sub 2}-Emissionen beitragen. Dabei kann die ausgekoppelte Waerme etwa zum gleichen Preis wie konventionell erzeugte Waerme abgegeben werden. Hoehere CO{sub 2}-Einsparungen lassen sich hingegen mit solarer Nahwaerme erzielen, allerdings zu hoeheren Kosten. Eine Kombination dieser beiden Waermetechniken verspricht Vorteile: Einerseits kann der Waermespeicher des Solarsystems auch zum Ausgleich von Lastspitzen beim Betrieb des BHKW`s genutzt werden. Andererseits kann die waehrend der einstrahlungsarmen Wintermonate fehlende solare Waerme durch das BHKW erzeugt werden. Detaillierte Simulations- und Optimierungsrechnungen zeigen jedoch, dass eine Kombination dieser Waermetechniken nicht immer empfehlenswert ist. (orig.)

  10. A numerical investigation of combined heat storage and extraction in deep geothermal reservoirs

    DEFF Research Database (Denmark)

    Major, Márton; Poulsen, Søren Erbs; Balling, Niels

    2018-01-01

    Heat storage capabilities of deep sedimentary geothermal reservoirs are evaluated through numerical model simulations. We combine storage with heat extraction in a doublet well system when storage phases are restricted to summer months. The effects of stored volume and annual repetition on energy...... recovery are investigated. Recovery factors are evaluated for several different model setups and we find that storing 90 °C water at 2500 m depth is capable of reproducing, on average 67% of the stored energy. In addition, ambient reservoir temperature of 75 °C is slightly elevated leading to increased...... efficiency. Additional simulations concerning pressure build-up in the reservoir are carried out to show that safety levels may not be reached. Reservoir characteristics are inspired by Danish geothermal conditions, but results are assumed to have more general validity. Thus, deep sedimentary reservoirs...

  11. An iterative procedure for estimating areally averaged heat flux using planetary boundary layer mixed layer height and locally measured heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Coulter, R. L.; Gao, W.; Lesht, B. M.

    2000-04-04

    Measurements at the central facility of the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) are intended to verify, improve, and develop parameterizations in radiative flux models that are subsequently used in General Circulation Models (GCMs). The reliability of this approach depends upon the representativeness of the local measurements at the central facility for the site as a whole or on how these measurements can be interpreted so as to accurately represent increasingly large scales. The variation of surface energy budget terms over the SGP CART site is extremely large. Surface layer measurements of the sensible heat flux (H) often vary by a factor of 2 or more at the CART site (Coulter et al. 1996). The Planetary Boundary Layer (PBL) effectively integrates the local inputs across large scales; because the mixed layer height (h) is principally driven by H, it can, in principal, be used for estimates of surface heat flux over scales on the order of tens of kilometers. By combining measurements of h from radiosondes or radar wind profiles with a one-dimensional model of mixed layer height, they are investigating the ability of diagnosing large-scale heat fluxes. The authors have developed a procedure using the model described by Boers et al. (1984) to investigate the effect of changes in surface sensible heat flux on the mixed layer height. The objective of the study is to invert the sense of the model.

  12. High-performance nanostructured thermoelectric generators for micro combined heat and power systems

    International Nuclear Information System (INIS)

    Zhang, Yanliang; Wang, Xiaowei; Cleary, Martin; Schoensee, Luke; Kempf, Nicholas; Richardson, Joseph

    2016-01-01

    Highlights: • A TEG is fabricated using high-efficiency nanostructured thermoelectric materials. • The TEG produces high power density of 2.1 W/cm"2 with 5.3% electrical efficiency. • A micro-CHP system is demonstrated by integrating the TEG into a gas-fired boiler. - Graphical Abstract: - Abstract: Micro combined heat and power (micro-CHP) systems are promising pathways to increase power generation efficiencies. Here a new class of micro-CHP system without moving parts is experimentally demonstrated by integrating high-temperature thermoelectric generators (TEGs) and residential gas-fired boilers, thus enabling wide applications. The TEGs fabricated using high-efficiency nanostructured bulk half-Heusler alloys generate ultrahigh power density of 2.1 W/cm"2 with 5.3% electrical efficiency under 500 °C temperature differences between the hot and cold sides. The TEG system harnesses the untapped exergy between the combustion gas and water, and converts thermal energy into electric power with 4% heat-to-electricity efficiency based on the total heat input into the TEGs. The high-performance TEGs open lots of opportunities to transform power generation technologies and improve energy efficiency.

  13. Fiscal 1993 investigational report on heat pump heat storage technology; 1993 nendo heat pump chikunetsu gijutsu ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-03-01

    This project is for an investigation into the heat pump (HP) use heat storage technology, with the aim of clarifying the present status of HP heat storage technology, the utilization status, and the developmental trend of technology and of contributing to the spread of heat energy effective use using HP heat storage technology and to the promotion of the technical development. Accordingly, the evaluation of the following was made: sensible heat (SH), latent heat (LH), chemical heat storage technology (CH), and heat storage technology (HS). Investigations were made on the sensible heat use heat storage technology of water, brine, stone, soil, etc. in terms of SH; the phase change sensible heat use heat storage technology of ice, hydrate salt, paraffins, etc. in terms of LH; hydration, hydroxide, 2-propanol pyrolysis, adsorption of silica gel, zeolite and water, and heat storage technology using metal hydride, etc. in terms of CH. In terms of HS, the following were studied and evaluated from the study results of the heat storage system in which HP is applied to the sensible heat and latent heat type heat storage technology: contribution to the power load levelling and the reduction of heat source capacity, heat recovery and the use of unused energy, improvement of the system efficiency by combining HP and heat storage technology. 24 refs., 242 figs., 56 tabs.

  14. Exergy analysis of a combined heat and power plant with integrated lignocellulosic ethanol production

    DEFF Research Database (Denmark)

    Lythcke-Jørgensen, Christoffer Ernst; Haglind, Fredrik; Clausen, Lasse Røngaard

    2014-01-01

    production. An exergy analysis is carried out for a modelled polygeneration system in which lignocellulosic ethanol production based on hydrothermal pretreatment is integrated in an existing combined heat and power (CHP) plant. The ethanol facility is driven by steam extracted from the CHP unit when feasible...... district heating production in the ethanol facility. The results suggest that the efficiency of integrating lignocellulosic ethanol production in CHP plants is highly dependent on operation, and it is therefore suggested that the expected operation pattern of such polygeneration system is taken......Lignocellulosic ethanol production is often assumed integrated in polygeneration systems because of its energy intensive nature. The objective of this study is to investigate potential irreversibilities from such integration, and what impact it has on the efficiency of the integrated ethanol...

  15. Decreased survival of prostate cancer cells in vitro by combined treatment of heat and an antioxidant inhibitor diethyldithiocarbamate (DDC).

    Science.gov (United States)

    Moriyama-Gonda, Nobuko; Igawa, Mikio; Shiina, Hiroaki; Urakami, Shinji; Terashima, Masaharu

    2003-11-01

    The aim of this study was to examine a modulation of thermotolerance by treatment with combination of heat and the antioxidant inhibitor diethyldithiocarbamate (DDC) of the PC-3 prostate cancer cells. To determine thermotolerance, cells were heated once or twice. Two 1 h exposures at 43 degrees C, with a recovery period in between, revealed better survival/recovery of cells after the second exposure than after the first (fig. 1A + 1B). Additional experiments were performed, heating cells twice (fig. 1B + 1C). First, cells were heated at 43 degrees C for 1 h and, after various recovery times (intervals) at 37 degree C, subsequently reheated at 44 degrees C for 1 h. To ensure effective cell killing, efficiency of the combined treatments of 1 mM DDC and heating at 43 or 44 degrees C for 1 h was estimated by measuring cell survival, reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity and heat shock protein 70 (hsp 70) expression. To obtain a more effective method for subsequent heat exposure, cells were heated twice after a 24 h interval in the presence or absence of 1 mM DDC. ROS generation and SOD activity immediately increased correlating with duration of heating, but their levels gently decreased with time after discontinuation of heating. On the other hand, hsp 70 levels slowly increased, also correlating with duration of heating but continued to increase with time after discontinuation of heating for a certain period. DDC administration coupled with heating at 43 or 44 degrees C significantly decreased cell survival compared to heating alone (p DDC as compared to heat alone at 43 and 44 degrees C (p DDC could have potential benefits in the treatment of prostate cancer.

  16. Effect of heating method on stress-rupture life

    Science.gov (United States)

    Bizon, P. T.; Calfo, F. D.

    1977-01-01

    The effect of radiant(furnace), resistance(electric current), burner(hot gas stream), and a combination of resistance and burner heating on intermediate time (100 to 300 hr) stress-rupture life and reduction of area was evaluated. All heating methods were studied using the nickel-based alloy Udimet 700 while all but burner heating were evaluated with the cobalt-based alloy Mar-M 509. Limited test results of eight other superalloys were also included in this study. Resistance heated specimens had about 20 to 30 percent of the stress-rupture life of radiant heated specimens. The limited burner heating data showed about a 50 percent life reduction as compared to the radiant heated tests. A metallurgical examination gave no explanation for these reductions.

  17. Modulation of Antioxidant Defense System Is Associated with Combined Drought and Heat Stress Tolerance in Citrus

    Directory of Open Access Journals (Sweden)

    Sara I. Zandalinas

    2017-06-01

    Full Text Available Drought and high temperatures are two major abiotic stress factors that often occur simultaneously in nature, affecting negatively crop performance and yield. Moreover, these environmental challenges induce oxidative stress in plants through the production of reactive oxygen species (ROS. Carrizo citrange and Cleopatra mandarin are two citrus genotypes with contrasting ability to cope with the combination of drought and heat stress. In this work, a direct relationship between an increased antioxidant activity and stress tolerance is reported. According to our results, the ability of Carrizo plants to efficiently coordinate superoxide dismutase (SOD, ascorbate peroxidase (APX, catalase (CAT, and glutathione reductase (GR activities involved in ROS detoxification along with the maintenance of a favorable GSH/GSSG ratio could be related to their relative tolerance to this stress combination. On the other hand, the increment of SOD activity and the inefficient GR activation along with the lack of CAT and APX activities in Cleopatra plants in response to the combination of drought and heat stress, could contribute to an increased oxidative stress and the higher sensibility of this citrus genotype to this stress combination.

  18. On the question of heat engine cycles optimization

    Directory of Open Access Journals (Sweden)

    Костянтин Ігорович Ткаченко

    2015-10-01

    Full Text Available It is known that the efficiency of heat engines nowadays isn’t more than 50-60% for prototypes and maximum possible efficiency of a heat engine is considered Carnot cycle efficiency Thus, at least 40% of the disposable amount of heat is lost in the surrounding medium, unless the waste gases heat is utilized somehow. General idea of heat engines cycles is the transfer of energy from the heater (both external and internal to a working fluid, obtaining mechanical work from expanding of the working fluid, and returning the working fluid to the initial state by compression and excess heat discharge into a cooler. In this paper the combination of a heat engine operating according to the standard Edwards cycle and consisting of isochor, adiabat and isotherm, and the heat pump, using the reverse Carnot cycle is investigated. The heat pump partially picks out the heat of the working fluid at its isothermal compression, and returns it to the equivalent working fluid or regenerator cap, at the beginning of isochoric heating. The efficiency coefficient of the heat pump, and thus the work to putting it into action is calculated by proper equations at the constant temperature of the low-potential heat source (working fluid and variable temperature of the heated equivalent of the working fluid or the regenerator cap. Taking as an example selected quantitative parameters of the Edwards cycle it has been proved that the use of the heat pump increases the effective efficiency of combined cycle as compared to the basic one. In addition, it has been shown that the dependence of the efficiency on the degree of heat return is not monotonic and has a maximum

  19. Inactivation of Escherichia coli in a tropical fruit smoothie by a combination of heat and pulsed electric fields.

    Science.gov (United States)

    Walkling-Ribeiro, M; Noci, F; Cronin, D A; Lyng, J G; Morgan, D J

    2008-10-01

    Moderate heat in combination with pulsed electric fields (PEF) was investigated as a potential alternative to thermal pasteurization of a tropical fruit smoothie based on pineapple, banana, and coconut milk, inoculated with Escherichia coli K12. The smoothie was heated from 25 degrees C to either 45 or 55 degrees C over 60 s and subsequently cooled to 10 degrees C. PEF was applied at electric field strengths of 24 and 34 kV/cm with specific energy inputs of 350, 500, and 650 kJ/L. Both processing technologies were combined using heat (45 or 55 degrees C) and the most effective set of PEF conditions. Bacterial inactivation was estimated on standard and NaCl-supplemented tryptone soy agar (TSA) to enumerate sublethally injured cells. By increasing the temperature from 45 to 55 degrees C, a higher reduction in E. coli numbers (1 compared with 1.7 log(10) colony forming units {CFU} per milliliter, P field strength was increased during stand-alone PEF treatment from 24 to 34 kV/cm, a greater number of E. coli cells were inactivated (2.8 compared with 4.2 log(10) CFU/mL, P or = 0.05) achieved by thermal pasteurization (72 degrees C, 15 s). A reversed hurdle processing sequence did not affect bacterial inactivation (P> or = 0.05). No differences were observed (P> or = 0.05) between the bacterial counts estimated on nonselective and selective TSA, suggesting that sublethal cell injury did not occur during single PEF treatments or combined heat/PEF treatments.

  20. Thermoeconomic Optimization of a Combined Heating and Humidification Coil for HVAC Systems

    Science.gov (United States)

    Teodoros, Liliana; Andresen, Bjarne

    2016-07-01

    The total cost of ownership is calculated for a combined heating and humidification coil of an air-handling unit taking into account investment and operation costs simultaneously. This total cost represents the optimization function for which the minimum is sought. The parameters for the cost dependencies are the physical dimensions of the coil: length, width and height. The term "coil" is used generically since in this setup it generates heating as well as humidification in a single unit. The first part of the paper deals with the constructive optimization and finds the relationship between the dimensions for a minimum cost. The second part of the paper takes the results of the constructive optimization further and, based on the data derived in our previous papers, analyzes the minimum total cost for the humidification coil while balancing the amount of water used to humidify the air and modify its temperature.

  1. Concentration of WWER-1000 unit power on one site

    International Nuclear Information System (INIS)

    Rousek, J.; Kysel, J.; Sladek, V.

    1987-01-01

    The problem of a suitable number of nuclear power plant units built on one site is discussed. Using an example of three sites being prepared now in Czechoslovakia, two alternatives - one with two WWER-1000 units, the other with four WWER-1000 units on one site - are evaluated from the viewpoint of long-range nuclear power development program in Czechoslovakia, costs, transmission of electric power and heat supply. (author). 10 tabs., 13 refs

  2. A study of performance parameters on drag and heat flux reduction efficiency of combinational novel cavity and opposing jet concept in hypersonic flows

    Science.gov (United States)

    Sun, Xi-wan; Guo, Zhen-yun; Huang, Wei; Li, Shi-bin; Yan, Li

    2017-02-01

    The drag reduction and thermal protection system applied to hypersonic re-entry vehicles have attracted an increasing attention, and several novel concepts have been proposed by researchers. In the current study, the influences of performance parameters on drag and heat reduction efficiency of combinational novel cavity and opposing jet concept has been investigated numerically. The Reynolds-average Navier-Stokes (RANS) equations coupled with the SST k-ω turbulence model have been employed to calculate its surrounding flowfields, and the first-order spatially accurate upwind scheme appears to be more suitable for three-dimensional flowfields after grid independent analysis. Different cases of performance parameters, namely jet operating conditions, freestream angle of attack and physical dimensions, are simulated based on the verification of numerical method, and the effects on shock stand-off distance, drag force coefficient, surface pressure and heat flux distributions have been analyzed. This is the basic study for drag reduction and thermal protection by multi-objective optimization of the combinational novel cavity and opposing jet concept in hypersonic flows in the future.

  3. Cost-benefit analysis for combined heat and power plant

    International Nuclear Information System (INIS)

    Sazdovski, Ace; Fushtikj, Vangel

    2004-01-01

    The paper presents a methodology and practical application of Cost-Benefit Analysis for Combined Heat and Power Plant (Cogeneration facility). Methodology include up-to-date and real data for cogeneration plant in accordance with the trends ill development of the CHP technology. As a case study a CHP plant that could be built-up in Republic of Macedonia is analyzed. The main economic parameters for project evaluation, such as NPV and IRR are calculated for a number of possible scenarios. The analyze present the economic outputs that could be used as a decision for CHP project acceptance for investment. (Author)

  4. WORKING PARK-FUEL CELL COMBINED HEAT AND POWER SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Allan Jones

    2003-09-01

    This report covers the aims and objectives of the project which was to design, install and operate a fuel cell combined heat and power (CHP) system in Woking Park, the first fuel cell CHP system in the United Kingdom. The report also covers the benefits that were expected to accrue from the work in an understanding of the full technology procurement process (including planning, design, installation, operation and maintenance), the economic and environmental performance in comparison with both conventional UK fuel supply and conventional CHP and the commercial viability of fuel cell CHP energy supply in the new deregulated energy markets.

  5. Specifying the auxiliary heating system on TFCX

    International Nuclear Information System (INIS)

    Metzler, D.H.

    1983-01-01

    This paper reviews the status of heating systems for the TFCX-S (all superconducting coil) and TFCX-H (hybrid coil) options. Three systems were defined; preheating (electron), current drive, and bulk (ion) heating. Application of systems engineering techniques facilitated fruitful discussions of requirements and their impact on equipment between physicists and engineers. A low-cost, flexible combination of systems allows plasma experiments using all rf startup and current drive

  6. Effects of a shortened depreciation schedule on the investment costs for combined heat and power; TOPICAL

    International Nuclear Information System (INIS)

    Kranz, Nicole; Worrell, Ernst

    2001-01-01

    We investigate and compare several generic depreciation methods to assess the effectiveness of possible policy measures with respect to the depreciation schedules for investments in combined heat and power plants in the United States. We assess the different depreciation methods for CHP projects of various sizes (ranging from 1 MW to 100 MW). We evaluate the impact of different depreciation schedules on the tax shield, and the resulting tax savings to potential investors. We show that a shorter depreciation cycle could have a substantial impact on the cost of producing power, making cogeneration more attractive. The savings amount to approximately 6-7 percent of capital and fixed operation and maintenance costs, when changing from the current system to a 7 year depreciation scheme with switchover from declining balance to straight line depreciation. Suggestions for further research to improve the analysis are given

  7. Power generation efficiency of an SOFC-PEFC combined system with time shift utilization of SOFC exhaust heat

    Energy Technology Data Exchange (ETDEWEB)

    Obara, Shin' ya [Power Engineering Lab., Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Kouen-cho, Kitami, Hokkaido 0908507 (Japan)

    2010-01-15

    A microgrid, with little environmental impact, is developed by introducing a combined SOFC (solid oxide fuel cell) and PEFC (proton exchange membrane fuel cell) system. Although the SOFC requires a higher operation temperature compared to the PEFC, the power generation efficiency of the SOFC is higher. However, if high temperature exhaust heat may be used effectively, a system with higher total power generation efficiency can be built. Therefore, this paper investigates the operation of a SOFC-PEFC combined system, with time shift operation of reformed gas, into a microgrid with 30 houses in Sapporo, Japan. The SOFC is designed to correspond to base load operation, and the exhaust heat of the SOFC is used for production of reformed gas. This reformed gas is used for the production of electricity for the PEFC, corresponding to fluctuation load of the next day. Accordingly, the reformed gas is used with a time shift operation. In this paper, the relation between operation method, power generation efficiency, and amount of heat storage of the SOFC-PEFC combined system to the difference in power load pattern was investigated. The average power generation efficiency of the system can be maintained at nearly 48% on a representative day in February (winter season) and August (summer season). (author)

  8. On multi-site damage identification using single-site training data

    Science.gov (United States)

    Barthorpe, R. J.; Manson, G.; Worden, K.

    2017-11-01

    This paper proposes a methodology for developing multi-site damage location systems for engineering structures that can be trained using single-site damaged state data only. The methodology involves training a sequence of binary classifiers based upon single-site damage data and combining the developed classifiers into a robust multi-class damage locator. In this way, the multi-site damage identification problem may be decomposed into a sequence of binary decisions. In this paper Support Vector Classifiers are adopted as the means of making these binary decisions. The proposed methodology represents an advancement on the state of the art in the field of multi-site damage identification which require either: (1) full damaged state data from single- and multi-site damage cases or (2) the development of a physics-based model to make multi-site model predictions. The potential benefit of the proposed methodology is that a significantly reduced number of recorded damage states may be required in order to train a multi-site damage locator without recourse to physics-based model predictions. In this paper it is first demonstrated that Support Vector Classification represents an appropriate approach to the multi-site damage location problem, with methods for combining binary classifiers discussed. Next, the proposed methodology is demonstrated and evaluated through application to a real engineering structure - a Piper Tomahawk trainer aircraft wing - with its performance compared to classifiers trained using the full damaged-state dataset.

  9. Waste heat recovery options in a large gas-turbine combined power plant

    Science.gov (United States)

    Upathumchard, Ularee

    This study focuses on power plant heat loss and how to utilize the waste heat in energy recovery systems in order to increase the overall power plant efficiency. The case study of this research is a 700-MW natural gas combined cycle power plant, located in a suburban area of Thailand. An analysis of the heat loss of the combustion process, power generation process, lubrication system, and cooling system has been conducted to evaluate waste heat recovery options. The design of the waste heat recovery options depends to the amount of heat loss from each system and its temperature. Feasible waste heat sources are combustion turbine (CT) room ventilation air and lubrication oil return from the power plant. The following options are being considered in this research: absorption chillers for cooling with working fluids Ammonia-Water and Water-Lithium Bromide (in comparison) and Organic Rankine Cycle (ORC) with working fluids R134a and R245fa. The absorption cycles are modeled in three different stages; single-effect, double-effect and half-effect. ORC models used are simple ORC as a baseline, ORC with internal regenerator, ORC two-phase flash expansion ORC and ORC with multiple heat sources. Thermodynamic models are generated and each system is simulated using Engineering Equation Solver (EES) to define the most suitable waste heat recovery options for the power plant. The result will be synthesized and evaluated with respect to exergy utilization efficiency referred as the Second Law effectiveness and net output capacity. Results of the models give recommendation to install a baseline ORC of R134a and a double-effect water-lithium bromide absorption chiller, driven by ventilation air from combustion turbine compartment. The two technologies yield reasonable economic payback periods of 4.6 years and 0.7 years, respectively. The fact that this selected power plant is in its early stage of operation allows both models to economically and effectively perform waste heat

  10. Separate and combined effects of exposure to heat stress and mental fatigue on endurance exercise capacity in the heat.

    Science.gov (United States)

    Otani, Hidenori; Kaya, Mitsuharu; Tamaki, Akira; Watson, Phillip

    2017-01-01

    This study investigated the effects of exposure to pre-exercise heat stress and mental fatigue on endurance exercise capacity in a hot environment. Eight volunteers completed four cycle exercise trials at 80% maximum oxygen uptake until exhaustion in an environmental chamber maintained at 30 °C and 50% relative humidity. The four trials required them to complete a 90 min pre-exercise routine of either a seated rest (CON), a prolonged demanding cognitive task to induce mental fatigue (MF), warm water immersion at 40 °C during the last 30 min to induce increasing core temperature (WI), or a prolonged demanding cognitive task and warm water immersion at 40 °C during the last 30 min (MF + WI). Core temperature when starting exercise was higher following warm water immersion (~38 °C; WI and MF + WI) than with no water immersion (~36.8 °C; CON and MF, P fatigue when commencing exercise was higher following cognitive task (MF and MF + WI) than with no cognitive task (CON and WI; P stress or mental fatigue, and this response is synergistically increased during combined exposure to them.

  11. Induction of heat-labile sites in DNA of mammalian cells by the antitumor alkylating drug CC-1065

    International Nuclear Information System (INIS)

    Zsido, T.J.; Woynarowski, J.M.; Baker, R.M.; Gawron, L.S.; Beerman, T.A.

    1991-01-01

    CC-1065 is a very potent antitumor antibiotic capable of covalent and noncovalent binding to the minor groove of naked DNA. Upon thermal treatment, covalent adducts formed between CC-1065 and DNA generate strand break. The authors have shown that this molecular damage can be detected following CC-1065 treatment of mammalian whole cells. Using alkaline sucrose gradient analysis, They observe thermally induced breakage of [ 14 C]thymidine-prelabeled DNA from drug-treated African green monkey kidney BSC-1 cells. Very little damage to cellular DNA by CC-1065 can be detected without first heating the drug-treated samples. CC-1065 can also generate heat-labile sites within DNA during cell lysis and heating, subsequent to the exposure of cells to drug, suggesting that a pool of free and noncovalently bound drug is available for posttreatment adduct formation. This effect was controlled for by mixing [ 3 H]thymidine-labeled untreated cells with the [ 14 C]thymidine-labeled drug-treated samples. The lowest drug dose at which heat-labile sites were detected was 3 nM CC-1065 (3 single-stranded breaks/10 6 base pairs). This concentration reduced survival of BSC-1 cells to 0.1% in cytotoxicity assays. The generation of CC-1065-induced lesions in cellular DNA is time dependent (the frequency of lesions caused by a 60 nM treatment reaching a plateau at 2 h) and is not readily reversible. The results of this study demonstrate that CC-1065 does generate heat-labile sites with the cellular DNA of intact cells and suggest that a mechanism of cytotoxic action of CC-1065 involves formation of covalent adducts to DNA

  12. Experimental study including subjective evaluations of mixing and displacement ventilation combined with radiant floor heating/cooling system

    DEFF Research Database (Denmark)

    Krajcik, Michal; Tomasi, Roberta; Simone, Angela

    2013-01-01

    Sixteen subjects evaluated the indoor environment in four experiments with different combinations of ventilation systems and radiant heating/cooling systems. In the first two tests, the simulated residential room was equipped either by a mixing ventilation system supplying warm air for space heat...

  13. Analytical and Experimental Feasibility Study of Combined OTEC on NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jeongtae; Oh, Kyemin; Heo, Gyunyoung [Kyung Hee Univ., Yongin (Korea, Republic of); Jung, Hoon [KEPCO Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    The concept of the Combined Ocean Thermal Energy Conversion (Combined OTEC) needs to study. Combined OTEC uses exhausted steam on Nuclear Power Plants (NPPs) as heat source instead surface water. Exhausted steam extracted from condenser evaporates working fluid of Combined OTEC at heat exchanger (Hx-W). Essential calculation for conceptual design of Combined OTEC was already performed and presented before. However, the technical issue whether sufficient extraction of exhausted steam from high degree of vacuum of condenser to Hx-W can be supplied or not was unclear, which is significant to continue a demonstration program. In this study, so, we calculated the rate of extracted steam to evaluate whether sufficient steam can be extracted using RELAP code. In aspect of implementation of Combined OTEC, confirmation of sufficient flow of exhausted steam into Hx-W is the starting point of research. As the result of RELAP calculation, we confirmed that exhausted steam would flow into Hx-W. Considering the amount of exhausted steam in NPPs which is 1000 MWe and has 36 % of efficiency, 9 % of flow rate to Hx-W is means that 160 MWt of heat can be available as heat source of Combined OTEC. Using this, it can be possible to improve efficiency of aged NPPs and can compensate power loss caused by increase of circulation water temperature particularly in summer season.

  14. Experimental investigation on heat transport in gravel-sand materials

    DEFF Research Database (Denmark)

    Maureschat, Gerald; Heller, Alfred

    1997-01-01

    in sand-gravel material, the storage media is to be water satured. In this case, handling of such material on site is rather complex. The conduction is highly dependent on the thermal properties of the storage media and so is the overall thermal performance of a storage applying such media. For sandy...... out in a small size experiment. The experiment consists of a highly insulated box filled with two kinds of sand material crossed by a plastic heat pipe. Heat transfer is measured under dry and water satured conditions in a cross-section.The conclusions are clear. To obtain necessary heat conduction...

  15. Environmental implications of carbon limits on market penetration of combined heat and power with the U.S. energy sector (Slides)

    Science.gov (United States)

    Combined heat and power (CHP) is promoted as an economical, energy-efficient option for combating climate change. To fully examine the viability of CHP as a clean-technology solution, its market potential and impacts need to be analyzed as part of scenarios of the future energy s...

  16. Influence of geologic layering on heat transport and storage in an aquifer thermal energy storage system

    Science.gov (United States)

    Bridger, D. W.; Allen, D. M.

    2014-01-01

    A modeling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in an aquifer thermal energy storage (ATES) system in Agassiz, British Columbia, Canada. Two 3D heat transport models were developed and calibrated using the flow and heat transport code FEFLOW including: a "non-layered" model domain with homogeneous hydraulic and thermal properties; and, a "layered" model domain with variable hydraulic and thermal properties assigned to discrete geological units to represent aquifer heterogeneity. The base model (non-layered) shows limited sensitivity for the ranges of all thermal and hydraulic properties expected at the site; the model is most sensitive to vertical anisotropy and hydraulic gradient. Simulated and observed temperatures within the wells reflect a combination of screen placement and layering, with inconsistencies largely explained by the lateral continuity of high permeability layers represented in the model. Simulation of heat injection, storage and recovery show preferential transport along high permeability layers, resulting in longitudinal plume distortion, and overall higher short-term storage efficiencies.

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

    Directory of Open Access Journals (Sweden)

    Costante Mario Invernizzi

    2018-04-01

    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%.

  18. Indoor temperatures for calculating room heat loss and heating capacity of radiant heating systems combined with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Olesen, Bjarne W.; Fang, Lei

    2016-01-01

    change rates on the indoor temperatures were performed using the proposed model. When heated surface temperatures and air change rates were from 21.0 to 29.0 degrees C and from 0.5 to 4.0 h-1, the indoor temperatures for calculating the transmission heat loss and ventilation heat loss were between 20...

  19. Antimicrobial activity of suspensions and nanoemulsions of citral in combination with heat or pulsed electric fields.

    Science.gov (United States)

    Pagán, E; Berdejo, D; Espina, L; García-Gonzalo, D; Pagán, R

    2018-01-01

    The application of essential oils in form of nanoemulsions has been proposed as a method to improve their solubility in aqueous solutions, and hence their antimicrobial activity. The objective of this study was to evaluate the antimicrobial activity of citral, applied directly or in combined treatments with heat or pulsed electric fields (PEF), as a function of the inoculation procedure assayed: (i) a simple, vigorous shaking method by vortex agitation (suspension of citral; s-citral) or (ii) the previous preparation of nanoemulsions by the emulsion phase inversion (EPI) method (nanoemulsion of citral; n-citral). n-Citral was more effective in either inhibiting or inactivating Escherichia coli O157:H7 Sakai than s-citral. However, when combined with heat, a greater synergistic effect was observed with s-citral rather than with n-citral, either in lab media (pH 7·0 and 4·0) or apple juice. For instance, while almost 5 log 10 cell cycles were inactivated in apple juice after 15 min at 53°C in the presence of 0·1 μl ml -1 of s-citral, the use of n-citral required 30 min. The use of nanoemulsions did not modify the slight synergism observed when citral and mild PEF were combined (150 μs, 30 kV cm -1 ). The exploration of different delivery systems of antimicrobial compounds such as citral in aqueous food products aids in the establishment of successful combined treatments for food preservation. While at room temperature, citral in form of a nanoemulsion shows a higher antimicrobial activity; its combination with heat would imply a partial loss of the outstanding synergistic lethal effect achieved when added in suspension form. Therefore, the most suitable procedure to magnify the synergism between heat and citral when processing juices would merely require an intense homogenization step prior to the combined treatment. © 2017 The Society for Applied Microbiology.

  20. Critical factors for profitable combined production of heat, power and biofuels; Kritiska faktorer foer loensam produktion i bioenergikombinat

    Energy Technology Data Exchange (ETDEWEB)

    Nohlgren, Ingrid; Gunnarsson, Emma; Lundqvist, Per; Stigander, Haakan; Widmark, Annika (AaF, Stockholm (Sweden))

    2012-02-15

    prerequisites for profitable polygeneration plants. The aim is that different actors within the energy and forest industry should be able to use the results in their own more detailed investment analysis. The project is based on data and material in open literature, in depth interviews of important actors and suppliers within this field, and, finally, an analysis by the authors. The project covers three different polygeneration plants: (1) Combined heat, power and wood pellet production, (2) combined heat, power and ethanol production, and (3) Bio-SNG and heat production

  1. Methods for estimating on-site ambient air concentrations at disposal sites

    International Nuclear Information System (INIS)

    Hwang, S.T.

    1987-01-01

    Currently, Gaussian type dispersion modeling and point source approximation are combined to estimate the ambient air concentrations of pollutants dispersed downwind of an areawide emission source, using the approach of virtual point source approximation. This Gaussian dispersion modeling becomes less accurate as the receptor comes closer to the source, and becomes inapplicable for the estimation of on-site ambient air concentrations at disposal sites. Partial differential equations are solved with appropriate boundary conditions for use in estimating the on-site concentrations in the ambient air impacted by emissions from an area source such as land disposal sites. Two variations of solution techniques are presented, and their predictions are compared

  2. Heat Modeling and Material Development of Mg-Based Nanomaterials Combined with Solid Oxide Fuel Cell for Stationary Energy Storage

    Directory of Open Access Journals (Sweden)

    Huaiyu Shao

    2017-11-01

    Full Text Available Mg-based materials have been investigated as hydrogen storage materials, especially for possible onboard storage in fuel cell vehicles for decades. Recently, with the development of large-scale fuel cell technologies, the development of Mg-based materials as stationary storage to supply hydrogen to fuel-cell components and provide electricity and heat is becoming increasingly promising. In this work, numerical analysis of heat balance management for stationary solid oxide fuel cell (SOFC systems combined with MgH2 materials based on a carbon-neutral design concept was performed. Waste heat from the SOFC is supplied to hydrogen desorption as endothermic heat for the MgH2 materials. The net efficiency of this model achieves 82% lower heating value (LHV, and the efficiency of electrical power output becomes 68.6% in minimizing heat output per total energy output when all available heat of waste gas and system is supplied to warm up the storage. For the development of Mg-based hydrogen storage materials, various nano-processing techniques have been widely applied to synthesize Mg-based materials with small particle and crystallite sizes, resulting in good hydrogen storage kinetics, but poor thermal conductivity. Here, three kinds of Mg-based materials were investigated and compared: 325 mesh Mg powers, 300 nm Mg nanoparticles synthesized by hydrogen plasma metal reaction, and Mg50Co50 metastable alloy with body-centered cubic structure. Based on the overall performances of hydrogen capacity, absorption kinetics and thermal conductivity of the materials, the Mg nanoparticle sample by plasma synthesis is the most promising material for this potential application. The findings in this paper may shed light on a new energy conversion and utilization technology on MgH2-SOFC combined concept.

  3. Options for greenhouse emission reduction by using a module for combined heat and power generation

    International Nuclear Information System (INIS)

    Stankov, Nikola; Ivanov, Bozhidar

    2009-01-01

    This report contains example of CO 2 emission reduction assessment when using module for combined heat and power generation that is fueled by natural gas. Environmental benefits are related to the type of fuel that is used and the increased efficiency of the combined production process. Choosing of the CHP unit and the assessment scheme are also presented

  4. Heat transfer: Pittsburgh 1987

    International Nuclear Information System (INIS)

    Lyczkowski, R.W.

    1987-01-01

    This book contains papers divided among the following sections: Process Heat Transfer; Thermal Hydraulics and Phase Change Phenomena; Analysis of Multicomponent Multiphase Flow and Heat Transfer; Heat Transfer in Advanced Reactors; General Heat Transfer in Solar Energy; Numerical Simulation of Multiphase Flow and Heat Transfer; High Temperature Heat Transfer; Heat Transfer Aspects of Severe Reactor Accidents; Hazardous Waste On-Site Disposal; and General Papers

  5. Hovering in the heat: effects of environmental temperature on heat regulation in foraging hummingbirds.

    Science.gov (United States)

    Powers, Donald R; Langland, Kathleen M; Wethington, Susan M; Powers, Sean D; Graham, Catherine H; Tobalske, Bret W

    2017-12-01

    At high temperature (greater than 40°C) endotherms experience reduced passive heat dissipation (radiation, conduction and convection) and increased reliance on evaporative heat loss. High temperatures challenge flying birds due to heat produced by wing muscles. Hummingbirds depend on flight for foraging, yet inhabit hot regions. We used infrared thermography to explore how lower passive heat dissipation during flight impacts body-heat management in broad-billed ( Cynanthus latirostris , 3.0 g), black-chinned ( Archilochus alexandri , 3.0 g), Rivoli's ( Eugenes fulgens , 7.5 g) and blue-throated ( Lampornis clemenciae , 8.0 g) hummingbirds in southeastern Arizona and calliope hummingbirds ( Selasphorus calliope , 2.6 g) in Montana. Thermal gradients driving passive heat dissipation through eye, shoulder and feet dissipation areas are eliminated between 36 and 40°C. Thermal gradients persisted at higher temperatures in smaller species, possibly allowing them to inhabit warmer sites. All species experienced extended daytime periods lacking thermal gradients. Broad-billed hummingbirds lacking thermal gradients regulated the mean total-body surface temperature at approximately 38°C, suggesting behavioural thermoregulation. Blue-throated hummingbirds were inactive when lacking passive heat dissipation and hence might have the lowest temperature tolerance of the four species. Use of thermal refugia permitted hummingbirds to tolerate higher temperatures, but climate change could eliminate refugia, forcing distributional shifts in hummingbird populations.

  6. 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

    Science.gov (United States)

    2013-01-01

    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

  7. Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

    International Nuclear Information System (INIS)

    Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

    2016-01-01

    Highlights: • An integrated thermal management system is proposed for electric vehicle. • The parallel branch of battery chiller can supply additional cooling capacity. • Heat pipe performance on preheating mode is better than that on cooling mode. • Heat pipe heat exchanger is a feasible choice for battery thermal management. - Abstract: An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is designed to meet the basic cabinet cooling demand, the additional parallel branch of battery chiller is a good way to solve the battery group cooling problem, which can supply about 20% additional cooling capacity without input power increase. Its coefficient of performance for cabinet heating is around 1.34 at −20 °C out-car temperature and 20 °C in-car temperature. The specific heat of the battery group is tested about 1.24 kJ/kg °C. There exists a necessary temperature condition for the heat pipe heat exchanger to start action. The heat pipe heat transfer performance is around 0.87 W/°C on cooling mode and 1.11 W/°C on preheating mode. The gravity role makes the heat transfer performance of the heat pipe on preheating mode better than that on cooling mode.

  8. An analysis on how proposed requirements for near zero energy buildings manages PV electricity in combination with two different types of heat pumps and its policy implications – A Swedish example

    International Nuclear Information System (INIS)

    Thygesen, Richard; Karlsson, Björn

    2017-01-01

    This paper presents an analysis on how exhaust air- and ground source- heat pumps in combination with PV-systems affects the specific energy demand of buildings with the proposed Swedish near zero energy building definition and its policy implications. It also presents a method on how to estimate the contribution from the photovoltaic-system on the reduction of the specific energy demand of the building. A challenge with the proposed near zero energy building definition is that it is not clearly defined how it manages photovoltaic electricity as a mean to reduce the specific energy demand of buildings. The results suggest that the building with the ground source heat pump and heat recovery ventilation has the lowest specific energy demand. The proposed definition will give an advantage to system combinations comprised of heat pumps and PV-systems and this will lead to the possibility to build less insulated buildings with higher heat losses than for a building with a non-electrical heating system. A higher share of heat pumps can lead to lower electricity production in Sweden because of lost heating loads in district heating systems and a higher electricity demand. - Highlights: • We analyzed how the proposed Swedish NZE building definition manages PV electricity. • The building with a GSHP has the lowest specific energy demand. • Two different assumptions on the usage of PV electricity was used. • The difference between the two assumptions is 6 kWh/m"2 for both the GSHP and EAHP.

  9. Power from waste. [Power plant at landfill site

    Energy Technology Data Exchange (ETDEWEB)

    Anon,

    1991-01-01

    Base Load Systems Ltd, a company in the United Kingdom, has just commissioned a power plant in Leicestershire which uses waste gases from a landfill site. The gases power two specially modified turbo charged engine and generator packages. The plant will use approximately 100 cu meters of landfill gas per hour and is expected to feed 1.5MW of electrical power into the supply network of East Midlands Electricity. Once the landfill site has been completely filled and capped with clay, it is estimated that the electrical power output will be 4 MW. At present, since their are no customers for heat in the vicinity, 100 KW of the electricity produced are used to run fans to dissipate the 2.5 MW of waste heat. Base load is also involved elsewhere in combined heat and power projects. (UK).

  10. Status report on preliminary design activities for solar heating and cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    1978-05-01

    Information presented provides status and progress on the development of solar heating and cooling systems. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities as part of the contract requirements.

  11. Two Examples of Exergy Optimization Regarding the “Thermo-Frigopump” and Combined Heat and Power Systems

    Directory of Open Access Journals (Sweden)

    Michel Feidt

    2013-02-01

    Full Text Available In a recent review an optimal thermodynamics and associated new upper bounds have been proposed, but it was only relative to power delivered by engines. In fact, it appears that for systems and processes with more than one utility (mainly mechanical or electrical power, energy conservation (First Law is limited for representing their efficiency. Consequently, exergy analysis combining the First and Second Law seems essential for optimization of systems or processes situated in their environment. For thermomechanical systems recent papers report on comparisons between energy and exergy analysis and corresponding optimization, but the proposed models mainly use heat transfer conductance modelling, except for internal combustion engine. Here we propose to reconsider direct and inverse configurations of Carnot machines, with two examples. The first example is concerned with “thermofrigo-pump” where the two utilities are hot and cold thermal exergies due to the difference in the temperature level compared to the ambient one. The second one is relative to a “combined heat and power” (CHP system. In the two cases, the model is developed based on the Carnot approach, and use of the efficiency-NTU method to characterize the heat exchangers. Obtained results are original thermodynamics optima, that represent exergy upper bounds for these two cases. Extension of the proposed method to other systems and processes is examined, with added technical constraints or not.

  12. Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

    Science.gov (United States)

    Lucazeau, F.; Rolandone, F.

    2012-08-01

    New temperature measurements from eight boreholes in the West African Craton (WAC) reveal superficial perturbations down to 100 m below the alteration zone. These perturbations are both related to a recent increase in the surface air temperature (SAT) and to the site effects caused by fluid circulations and/or the lower conduction in the alterites. The ground surface temperature (GST), inverted from the boreholes temperatures, increased slowly in the past (~0.4 °C from 1700 to 1940) and then, more importantly, in recent years (~1.5 °C from 1940 to 2010). This recent trend is consistent with the increase of the SAT recorded at two nearby meteorological stations (Tambacounda and Kedougou), and more generally in the Sahel with a coeval rainfall decrease. Site effects are superimposed to the climatic effect and interpreted by advective (circulation of fluids) or conductive (lower conductivity of laterite and of high-porosity sand) perturbations. We used a 1-D finite differences thermal model and a Monte-Carlo procedure to find the best estimates of these site perturbations: all the eight borehole temperature logs can be interpreted with the same basal heat-flow and the same surface temperature history, but with some realistic changes of thermal conductivity and/or fluid velocity. The GST trend observed in Senegal can be confirmed by two previous borehole measurements made in 1983 in other locations of West Africa, the first one in an arid zone of northern Mali and the second one in a sub-humid zone in southern Mali. Finally, the background heat-flow is low (31±2 mW m-2), which makes this part of the WAC more similar with the observations in the southern part (33±8 mW m-2) rather than with those in the northern part and in the Pan-African domains where the surface heat-flow is 15-20 mW m-2 higher.

  13. Multi-objective optimization and exergoeconomic analysis of a combined cooling, heating and power based compressed air energy storage system

    International Nuclear Information System (INIS)

    Yao, Erren; Wang, Huanran; Wang, Ligang; Xi, Guang; Maréchal, François

    2017-01-01

    Highlights: • A novel tri-generation based compressed air energy storage system. • Trade-off between efficiency and cost to highlight the best compromise solution. • Components with largest irreversibility and potential improvements highlighted. - Abstract: Compressed air energy storage technologies can improve the supply capacity and stability of the electricity grid, particularly when fluctuating renewable energies are massively connected. While incorporating the combined cooling, heating and power systems into compressed air energy storage could achieve stable operation as well as efficient energy utilization. In this paper, a novel combined cooling, heating and power based compressed air energy storage system is proposed. The system combines a gas engine, supplemental heat exchangers and an ammonia-water absorption refrigeration system. The design trade-off between the thermodynamic and economic objectives, i.e., the overall exergy efficiency and the total specific cost of product, is investigated by an evolutionary multi-objective algorithm for the proposed combined system. It is found that, with an increase in the exergy efficiency, the total product unit cost is less affected in the beginning, while rises substantially afterwards. The best trade-off solution is selected with an overall exergy efficiency of 53.04% and a total product unit cost of 20.54 cent/kWh, respectively. The variation of decision variables with the exergy efficiency indicates that the compressor, turbine and heat exchanger preheating the inlet air of turbine are the key equipment to cost-effectively pursuit a higher exergy efficiency. It is also revealed by an exergoeconomic analysis that, for the best trade-off solution, the investment costs of the compressor and the two heat exchangers recovering compression heat and heating up compressed air for expansion should be reduced (particularly the latter), while the thermodynamic performance of the gas engine need to be improved

  14. Investigations and model validation of a ground-coupled heat pump for the combination with solar collectors

    International Nuclear Information System (INIS)

    Pärisch, Peter; Mercker, Oliver; Warmuth, Jonas; Tepe, Rainer; Bertram, Erik; Rockendorf, Gunter

    2014-01-01

    The operation of ground-coupled heat pumps in combination with solar collectors requires comprising knowledge of the heat pump behavior under non-standard conditions. Especially higher temperatures and varying flow rates in comparison to non-solar systems have to be taken into account. Furthermore the dynamic behavior becomes more important. At ISFH, steady-state and dynamic tests of a typical brine/water heat pump have been carried out in order to analyze its behavior under varying operation conditions. It has been shown, that rising source temperatures do only significantly increase the coefficient of performance (COP), if the source temperature is below 10–20 °C, depending on the temperature lift between source and sink. The flow rate, which has been varied both on the source and the sink side, only showed a minor influence on the exergetic efficiency. Additionally a heat pump model for TRNSYS has been validated under non-standard conditions. The results are assessed by means of TRNSYS simulations. -- Highlights: • A brine/water heat pump was tested under steady-state and transient conditions. • Decline of exergetic efficiency at low temperature lifts, no influence of flow rate. • Expected improvement by reciprocating compressor and electronic expansion valve for solar assisted heat source. • A TRNSYS black box model (YUM) was validated and a flow rate correction was proven • The start-up behavior is a very important parameter for system simulations

  15. Removal of sulphur-containing odorants from fuel gases for fuel cell-based combined heat and power applications

    NARCIS (Netherlands)

    Wild, de P.J.; Nyqvist, R.G.; Bruijn, de F.A.; Stobbe, E.R.

    2006-01-01

    Natural gas (NG) and liquefied petroleum gas (LPG) are important potential feedstocks for the production of hydrogen for fuel cell-based(e.g. proton exchange membrane fuel cells (PEMFC) or solid oxide fuel Cells (SOFC) combined heat and power (CHP) applications. To preventdetrimental effects on the

  16. Grimsel Test Site: heat test, final report

    International Nuclear Information System (INIS)

    Schneefuss, J.; Glaess, F.; Gommlich, G.; Schmidt, M.

    1989-05-01

    The Swiss concept for the storage of radioactive waste consists in placing it in compact, dense rock formations. An experiment 'Heat Test' carried out by the 'Gesellschaft fuer Strahlen- und Umweltforschung' in Nagra's Grimsel rock laboratory simulated the heat production of stored radioactive waste. The aim was to evaluate processes for the demonstration of the suitability of a final repository for heat-producing radioactive waste in cristalline rock, to investigate the thermic, mechanic and hydraulic reactions to an artificial heat source, and to develop corresponding calculating models. The duration of the tests was about 3 years. In this report the measured thermic, mechanic and hydraulic reactions are documented and discussed in detail. A simple, rotation symmetrical FEM-model was used for the preparatory and experiment-accompanying modelling of the thermomechanical conditions in the heat test. The test showed that suitable measuring methods for the surveillance of the geomechanics of a final repository are available and that the reactions of the crystalline host rock to the heat source remain locally limited and can be modelled with relatively small effort. 29 refs., 33 figs., 10 tabs

  17. Heat pipe heat exchangers in heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Stulc, P; Vasiliev, L L; Kiseljev, V G; Matvejev, Ju N

    1985-01-01

    The results of combined research and development activities of the National Research Institute for Machine Design, Prague, C.S.S.R. and the Institute for Heat and Mass Transfer, Minsk, U.S.S.R. concerning intensification heat pipes used in heat pipe heat exchangers are presented. This sort of research has been occasioned by increased interest in heat power economy trying to utilise waste heat produced by various technological processes. The developed heat pipes are deployed in construction of air-air, gas-air or gas-gas heat recovery exchangers in the field of air-engineering and air-conditioning. (author).

  18. Combined heat and power from the intermediate pyrolysis of biomass materials: performance, economics and environmental impact

    International Nuclear Information System (INIS)

    Yang, Y.; Brammer, J.G.; Wright, D.G.; Scott, J.A.; Serrano, C.; Bridgwater, A.V.

    2017-01-01

    Highlights: • Performance of the Pyrolysis and CHP systems is studied and evaluated. • Overall CHP efficiency of the 1000 kg/h Pyro-CHP system is 42.5%. • Levelised Energy Cost is high, but the optimistic scenario is potentially profitable. • Life-cycle GHG analysis shows strong positive environmental benefits. - Abstract: Combined heat and power from the intermediate pyrolysis of biomass materials offers flexible, on-demand renewable energy with some significant advantages over other renewable routes. To maximise the deployment of this technology an understanding of the dynamics and sensitivities of such a system is required. In the present work the system performance, economics and life-cycle environmental impact is analysed with the aid of the process simulation software Aspen Plus. Under the base conditions for the UK, such schemes are not currently economically competitive with energy and char products produced from conventional means. However, under certain scenarios as modelled using a sensitivity analysis this technology can compete and can therefore potentially contribute to the energy and resource sustainability of the economy, particularly in on-site applications with low-value waste feedstocks. The major areas for potential performance improvement are in reactor cost reductions, the reliable use of waste feedstocks and a high value end use for the char by-product from pyrolysis.

  19. Small-Scale Combined Heat and Power Plants Using Biofuels

    Energy Technology Data Exchange (ETDEWEB)

    Salomon-Popa, Marianne [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Technology

    2002-11-01

    In this time period where energy supply and climate change are of special concern, biomass-based fuels have attracted much interest due to their plentiful supply and favorable environmental characteristics (if properly managed). The effective capture and continued sustainability of this renewable resource requires a new generation of biomass power plants with high fuel energy conversion. At the same time, deregulation of the electricity market offers new opportunities for small-scale power plants in a decentralized scheme. These two important factors have opened up possibilities for small-scale combined heat and power (CHP) plants based on biofuels. The objective of this pre-study is to assess the possibilities and technical limitations for increased efficiency and energy utilization of biofuels in small size plants (approximately 10 MWe or lower). Various energy conversion technologies are considered and proven concepts for large-scale fossil fuel plants are an especially important area. An analysis has been made to identify the problems, technical limitations and different possibilities as recognized in the literature. Beyond published results, a qualitative survey was conducted to gain first-hand, current knowledge from experts in the field. At best, the survey results together with the results of personal interviews and a workshop on the role of small-scale plants in distributed generation will serve a guideline for future project directions and ideas. Conventional and novel technologies are included in the survey such as Stirling engines, combustion engines, gas turbines, steam turbines, steam motors, fuel cells and other novel technologies/cycles for biofuels. State-of-the-art heat and power plants will be identified to clarify of the advantages and disadvantages as well as possible obstacles for their implementation.

  20. Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

    Directory of Open Access Journals (Sweden)

    Dongmin Yu

    2017-06-01

    Full Text Available Many combined heat and power (CHP units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity and heat loads are firstly used as sizing criteria in finding the best capacities of different types of CHP with the help of the maximum rectangle (MR method. Subsequently, the genetic algorithm (GA will be used to optimise the daily energy costs of the different cases. Then, heat and electricity loads are jointly considered for sizing different types of CHP and for optimising the daily energy costs through the GA method. The optimisation results show that the GA sizing method gives a higher average daily energy cost saving, which is 13% reduction compared to a building without installing CHP. However, to achieve this, there will be about 3% energy efficiency reduction and 7% input power to rated power ratio reduction compared to using the MR method and heat demand in sizing CHP.

  1. Solar thermal space heating combined with swimming pool heating: A promising solution for southern Europe climates

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, M.J.; Neves, Ana [INETI/DER, Lisboa (Portugal)

    2006-07-01

    The system concept evaluation performed focused on systems that can provide hot water, space heating and swimming-pool heating, and are designed for application in southern climates specifically for single-family houses. Due to the climate characteristics of southern Europe, space heating is required only for a few months in the year. In this evaluation it was considered a six month period for space heating and, on the other six months, swimming pool heating was considered. This type of systems are applicable to a niche market of people who are building their houses as single-family houses and want also to take profit of the good climate conditions for the use of solar energy. It is common that the construction of a swimming pool is also planned and constructed. The evaluation is made considering as reference system a factory made with 4m{sup 2} collector area and 300 l storage tank. The system in evaluation offers extra service - space heating and swimming pool heating and is formed by a collector field and a combistore providing solar hot water preparation and space heating in the winter period and providing also swimming pool heating in the summer period. The evaluation made shows that in southern Europe climates this system will give extra service in comparison to the traditional solar systems used and can be economically interesting.

  2. Technical Analysis of Installed Micro-Combined Heat and Power Fuel-Cell System

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Kriston P.; Makhmalbaf, Atefe

    2014-10-31

    Combined heat and power fuel cell systems (CHP-FCSs) provide consistent electrical power and hot water with greater efficiency and lower emissions than alternative sources. These systems can be used either as baseload, grid-connected, or as off-the-grid power sources. This report presents a technical analysis of 5 kWe CHP-FCSs installed in different locations in the U.S. At some sites as many as five 5 kWe system is used to provide up to 25kWe of power. Systems in this power range are considered “micro”-CHP-FCS. To better assess performance of micro-CHP-FCS and understand their benefits, the U.S. Department of Energy worked with ClearEdge Power to install fifteen 5-kWe PBI high temperature PEM fuel cells (CE5 models) in the commercial markets of California and Oregon. Pacific Northwest National Laboratory evaluated these systems in terms of their economics, operations, and technical performance. These units were monitored from September 2011 until June 2013. During this time, about 190,000 hours of data were collected and more than 17 billion data points were analyzed. Beginning in July 2013, ten of these systems were gradually replaced with ungraded systems (M5 models) containing phosphoric acid fuel cell technology. The new units were monitored until June 2014 until they went offline because ClearEdge was bought by Doosan at the time and the new manufacturer did not continue to support data collection and maintenance of these units. During these two phases, data was collected at once per second and data analysis techniques were applied to understand behavior of these systems. The results of this analysis indicate that systems installed in the second phase of this demonstration performed much better in terms of availability, consistency in generation, and reliability. The average net electrical power output increased from 4.1 to 4.9 kWe, net heat recovery from 4.7 to 5.4 kWth, and system availability improved from 94% to 95%. The average net system electric

  3. The effects of frost thickness on the heat transfer of finned tube heat exchanger subject to the combined influence of fan types

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jeng-Min; Hsieh, Wen-Chien; Ke, Xin-Ji [Department of Refrigeration, Air Conditioning National Chin-Yi University of Technology, Taichung County, Taiping City 411 (China); Wang, Chi-Chuan [Energy and Environment Research Laboratories, Industrial Technology Research Institute, Hsinchu 310 (China)

    2008-05-15

    This study conducts a numerical study concerning the effect of frost thickness on the heat transfer performance of a four rows plate finned tube heat exchanger. Calculations are made under constant air volume and variable air volume conditions. It is found that the initial surge of heat transfer rate in the frosted finned tube heat exchanger is mainly associated with the critical radius effect rather than the surface roughness. The frost thermal conductivity plays an important role in the surge phenomenon. There is hardly any initial surge when frost thermal conductivity is below 0.1 W m{sup -1} K{sup -1}. It is also recommended that a refrigerator should defrost when half of a single flow channel area is blocked by frost. The calculations also reveal that a centrifugal fan is recommended with a small fin-pitch heat exchanger. However, if a long term operation at a thick frost situation is unavoidable, an axial fan should be selected. There is no great difference between selection of an axial fan or centrifugal fan for a larger fin pitch heat exchanger. (author)

  4. Energy management strategies for combined heat and electric power micro-grid

    Directory of Open Access Journals (Sweden)

    Barbarić Marina

    2016-01-01

    Full Text Available The increasing energy production from variable renewable energy sources such as wind and solar has resulted in several challenges related to the system reliability and efficiency. In order to ensure the supply-demand balance under the conditions of higher variability the micro-grid concept of active distribution networks arising as a promising one. However, to achieve all the potential benefits that micro-gird concept offer, it is important to determine optimal operating strategies for micro-grids. The present paper compares three energy management strategies, aimed at ensuring economical micro-grid operation, to find a compromise between the complexity of strategy and its efficiency. The first strategy combines optimization technique and an additional rule while the second strategy is based on the pure optimization approach. The third strategy uses model based predictive control scheme to take into account uncertainties in renewable generation and energy consumption. In order to compare the strategies with respect to cost effectiveness, a residential micro-grid comprising photovoltaic modules, thermal energy storage system, thermal loads, electrical loads as well as combined heat and power plant, is considered.

  5. Experimental investigation on an integrated thermal management system with heat pipe heat exchanger for electric vehicle

    OpenAIRE

    Zou, Huiming; Wang, Wei; Zhang, Guiying; Qin, Fei; Tian, Changqing; Yan, Yuying

    2016-01-01

    An integrated thermal management system combining a heat pipe battery cooling/preheating system with the heat pump air conditioning system is presented to fulfill the comprehensive energy utilization for electric vehicles. A test bench with battery heat pipe heat exchanger and heat pump air conditioning for a regular five-chair electric car is set up to research the performance of this integrated system under different working conditions. The investigation results show that as the system is d...

  6. Ultra Efficient CHHP Using a High Temperature Fuel Cell to Provide On-Site Process Reducing Gas, Clean Power, and Heat

    Energy Technology Data Exchange (ETDEWEB)

    Jahnke, Fred C. [Fuelcell Energy, Inc., Danbury, CT (United States)

    2015-06-30

    FuelCell Energy and ACuPowder investigated and demonstrated the use of waste anode exhaust gas from a high temperature fuel cell for replacing the reducing gas in a metal processing furnace. Currently companies purchase high pressure or liquefied gases for the reducing gas which requires substantial energy in production, compression/liquefaction, and transportation, all of which is eliminated by on-site use of anode exhaust gas as reducing gas. We performed research on the impact of the gas composition on product quality and then demonstrated at FuelCell Energy’s manufacturing facility in Torrington, Connecticut. This demonstration project continues to operate even though the research program is completed as it provides substantial benefits to the manufacturing facility by supplying power, heat, and hydrogen.

  7. Effect of bar sealing parameters on OPP/MCPP heat seal strength

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available The effect of bar sealing parameters on the heat seal strength of oriented polypropylene (OPP/metallic cast polypropylene (MCPP laminate film was investigated. Based on the results obtained from the parametric study, a bar sealing process window was developed. All points drop within the process window are combinations of platen temperature and dwell time that produce acceptable heat seal. Optimum combinations are indicated by the lower border of the window. The plateau initiation temperature, Tpi of OPP/MCPP laminate film used in the present study occurred before the final melting temperature, Tmf of the sealant material. The highest achievable heat seal strength was at the plateau region, and the corresponding failure modes were delaminating, tearing or combine failure modes (delaminating and tearing. Minimum pressure level of 1.25 bars is necessary to bring the laminate interface into intimate contact in order to effect sealing.

  8. Heat flux estimate of warm water flow in a low-temperature diffuse flow site, southern East Pacific Rise 17°25‧ S

    Science.gov (United States)

    Goto, Shusaku; Kinoshita, Masataka; Mitsuzawa, Kyohiko

    2003-09-01

    A low-temperature diffuse flow site associated with abundant vent fauna was found by submersible observations on the southern East Pacific Rise at 17°25‧ S in 1997. This site was characterized by thin sediment covered pillow and sheet lavas with collapsed pits up to ˜15 m in diameter. There were three warm water vents (temperature: 6.5 to 10.5 °C) within the site above which the vented fluids rise as plumes. To estimate heat flux of the warm water vents, a temperature logger array was deployed and the vertical temperature distribution in the water column up to 38 m above the seafloor was monitored. A stationary deep seafloor observatory system was also deployed to monitor hydrothermal activity in this site. The temperature logger array measured temperature anomalies, while the plumes from the vents passed through the array. Because the temperature anomalies were measured in only specific current directions, we identified one of the vents as the source. Heat flux from the vent was estimated by applying a plume model in crossflow in a density-stratified environment. The average heat flux from September 13 to October 18, 1997 was 39 MW. This heat flux is as same order as those of high-temperature black smokers, indicating that a large volume flux was discharged from the vent (1.9 m3/s). Previous observations found many similar warm water flow vents along the spreading axis between 17°20‧ S 30‧ S. The total heat flux was estimated to be at least a few hundred mega-watts. This venting style would contribute to form effluent hydrothermal plumes extended above the spreading axis.

  9. Performance and costs of a roof-sized PV/thermal array combined with a ground coupled heat pump

    NARCIS (Netherlands)

    Bakker, M.; Zondag, H.A.

    2005-01-01

    A photovoltaic/thermal (PVT) panel is a combination of photovoltaic cells with a solar thermal collector, generating solar electricity and solar heat simultaneously. Hence, PVT panels are an alternative for a combination of separate PV panels and solar thermal collectors. A promising system concept,

  10. 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.

    2005-06-01

    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

  11. Optimal design and operating strategies for a biomass-fueled combined heat and power system with energy storage

    DEFF Research Database (Denmark)

    Zheng, Yingying; Jenkins, Bryan M.; Kornbluth, Kurt

    2018-01-01

    An economic linear programming model with a sliding time window was developed to assess designing and scheduling a biomass-fueled combined heat and power system consisting of biomass gasifier, internal combustion engine, heat recovery set, heat-only boiler, producer gas storage and thermal energy......, utility tariff structure and technical and finical performance of the system components. Engine partial load performance was taken into consideration. Sensitivity analyses demonstrate how the optimal BCHP configuration changes with varying demands and utility tariff rates....

  12. Experiences with on-site power sources at KCB

    Energy Technology Data Exchange (ETDEWEB)

    Heijnen, B. M.A. [Borssele Nuclear Power Station, N.V. P.Z.E.M., Postbus 48, 4330 AA Middleburg (Netherlands)

    1986-02-15

    The design of the nuclear power station is of the late sixties. The experiences with the on-site power sources, signal processing and some of the resulting modifications of the design of the power plant are mentioned. In order to let the design satisfy as much as possible present ideas about safety, it was decided to realize a total new and Independent decay heat removal System. With this system a second independent on-site power System is at disposal in case of accident situations. (author)

  13. Development of a combined soil-wash/in-furnace vitrification system for soil remediation at DOE sites

    International Nuclear Information System (INIS)

    Pegg, I.L.; Guo, Y.; Lahoda, E.J.; Lai, Shan-Tao; Muller, I.S.; Ruller, J.; Grant, D.C.

    1993-01-01

    This report addresses research and development of technologies for treatment of radioactive and hazardous waste streams at DOE sites. Weldon Spring raffinate sludges were used in a direct vitrification study to investigate their use as fluxing agents in glass formulations when blended with site soil. Storm sewer sediments from the Oak Ridge, TN, Y-12 facility were used for soil washing followed by vitrification of the concentrates. Both waste streams were extensively characterized. Testing showed that both mercury and uranium could be removed from the Y-12 soil by chemical extraction resulting in an 80% volume reduction. Thermal desorption was used on the contaminant-enriched minority fraction to separate the mercury from the uranium. Vitrification tests demonstrated that high waste loading glasses could be produced from the radioactive stream and from the Weldon Spring wastes which showed very good leach resistance, and viscosities and electrical conductivities in the range suitable for joule-heated ceramic melter (JHCM) processing. The conceptual process described combines soil washing, thermal desorption, and vitrification to produce clean soil (about 90% of the input waste stream), non-radioactive mercury, and a glass wasteform; the estimated processing costs for that system are about $260--$400/yd 3 . Results from continuous melter tests performed using Duratek's advanced JHCM (Duramelter) system are also presented. Since life cycle cost estimates are driven largely by volume reduction considerations, the large volume reductions possible with these multi-technology, blended waste stream approaches can produce a more leach resistant wasteform at a lower overall cost than alternative technologies such as cementation

  14. Novel approaches for an enhanced geothermal development of residential sites

    Science.gov (United States)

    Schelenz, Sophie; Firmbach, Linda; Shao, Haibing; Dietrich, Peter; Vienken, Thomas

    2015-04-01

    An ongoing technological enhancement drives an increasing use of shallow geothermal systems for heating and cooling applications. However, even in areas with intensive shallow geothermal use, planning of geothermal systems is in many cases solely based on geological maps, drilling databases, and literature references. Thus, relevant heat transport parameters are rather approximated than measured for the specific site. To increase the planning safety and promote the use of renewable energies in the domestic sector, this study investigates a novel concept for an enhanced geothermal development of residential neighbourhoods. This concept is based on a site-specific characterization of subsurface conditions and the implementation of demand-oriented geothermal usage options. Therefore, an investigation approach has been tested that combines non-invasive with minimum-invasive exploration methods. While electrical resistivity tomography has been applied to characterize the geological subsurface structure, Direct Push soundings enable a detailed, vertical high-resolution characterization of the subsurface surrounding the borehole heat exchangers. The benefit of this site-specific subsurface investigation is highlighted for 1) a more precise design of shallow geothermal systems and 2) a reliable prediction of induced long-term changes in groundwater temperatures. To guarantee the financial feasibility and practicability of the novel geothermal development, three different options for its implementation in residential neighbourhoods were consequently deduced.

  15. Model for optimization of plant investments in combined power and heat production systems

    Energy Technology Data Exchange (ETDEWEB)

    Jantunen, E.; Sinisalo, A.; Koskelainen, L.

    1980-01-01

    A mathematical model is developed for optimal dimensioning and timing the investments of power and heat production system in a community. The required electric power may be purchased by different production systems, such as: thermal power plants, gas turbines, diesel plants, etc. or by delivering all or part of it from a national power company. Also the required heat may be produced in many different ways in single-purpose or combined plants. The model assumes the extent of the heating system fixed, and it is not optimized. It is assumed that the same company is responsible for supplying both the power and heat for the community. It's aim is to allocate the existing capital in an optimal way, and the model may be used for facilitating the decision in such questions as: what kind of production capacity should be purchased in future; how high should the heat and power capacities be; and when should this additional capacity be available. The report also reviews the methods for forecasting the demand of power and heat and their fluctuation during the planning period. The solution of this large-scale non-linear optimization problem is searched via successive linearizations by using the Method of Approximate Programming (MAP). It was found that the solution method is very suitable for this kind of multivariable problems. The computing times with the Functional Mathematical Programmin System (FMPS) in Univac 1108 computer were quite reasonable.

  16. Optimal coordinated scheduling of combined heat and power fuel cell, wind, and photovoltaic units in micro grids considering uncertainties

    International Nuclear Information System (INIS)

    Bornapour, Mosayeb; Hooshmand, Rahmat-Allah; Khodabakhshian, Amin; Parastegari, Moein

    2016-01-01

    In this paper, a stochastic model is proposed for coordinated scheduling of combined heat and power units in micro grid considering wind turbine and photovoltaic units. Uncertainties of electrical market price; the speed of wind and solar radiation are considered using a scenario-based method. In the method, scenarios are generated using roulette wheel mechanism based on probability distribution functions of input random variables. Using this method, the probabilistic specifics of the problem are distributed and the problem is converted to a deterministic one. The type of the objective function, coordinated scheduling of combined heat and power, wind turbine, and photovoltaic units change this problem to a mixed integer nonlinear one. Therefore to solve this problem modified particle swarm optimization algorithm is employed. The mentioned uncertainties lead to an increase in profit. Moreover, the optimal coordinated scheduling of renewable energy resources and thermal units in micro grids increase the total profit. In order to evaluate the performance of the proposed method, its performance is executed on modified 33 bus distributed system as a micro grid. - Highlights: • Stochastic model is proposed for coordinated scheduling of renewable energy sources. • The effect of combined heat and power is considered. • Maximizing profits of micro grid is considered as objective function. • Considering the uncertainties of problem lead to profit increasing. • Optimal scheduling of renewable energy sources and thermal units increases profit.

  17. Combined natural convection and mass transfer effects on unsteady flow past an infinite vertical porous plate embedded in a porous medium with heat source

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.S. [Department of Physics, K B D A V College, Nirakarpur, Khurda-752 019 (Orissa) (India); Tripathy, R.K. [Department of Physics, D R Nayapalli College, Bhubaneswar-751 012 (Orissa) (India); Padhy, R.K. [Department of Physics, D A V Public School, Chandrasekharpur, Bhubaneswar-751 021 (Orissa) (India); Sahu, M. [Department of Physics, Jupiter +2 Women’s Science College, IRC Village, Bhubaneswar-751 015 (Orissa) (India)

    2012-07-01

    This paper theoretically investigates the combined natural convection and mass transfer effects on unsteady flow of a viscous incompressible fluid past an infinite vertical porous plate embedded in a porous medium with heat source. The governing equations of the flow field are solved analytically for velocity, temperature, concentration distribution, skin friction and the rate of heat transfer using multi parameter perturbation technique and the effects of the flow parameters such as permeability parameter Kp, Grashof number for heat and mass transfer Gr, Gc; heat source parameter S, Schmidt number Sc, Prandtl number Pr etc. on the flow field are analyzed and discussed with the help of figures and tables. The permeability parameter Kp is reported to accelerate the transient velocity of the flow field at all points for small values of Kp (£1) and for higher values the effect reverses. The effect of increasing Grashof numbers for heat and mass transfer or heat source parameter is to enhance the transient velocity of the flow field at all points while a growing Schmidt number retards its effect at all points. A growing permeability parameter or heat source parameter increases the transient temperature of the flow field at all points, while a growing Prandtl number shows reverse effect. The effect of increasing Schmidt number is to decrease the concentration boundary layer thickness of the flow field at all points. Further, a growing permeability parameter enhances the skin friction at the wall and a growing Prandtl number shows reverse effect. The effect of increasing Prandtl number or permeability parameter leads to increase the magnitude of the rate of heat transfer at the wall.

  18. Effect of radiation combined with hyperthermia on human prostatic carcinoma cell lines in culture

    International Nuclear Information System (INIS)

    Kaver, I.; Ware, J.L.; Wilson, J.D.; Koontz, W.W. Jr.

    1991-01-01

    The effect of radiation combined with heat on three human prostatic carcinoma cell lines growing in vitro was investigated. Cells were exposed to different radiation doses followed by heat treatment at 43 degrees C for one hour. Heat treatment, given ten minutes after radiation, significantly enhanced the radiation response of all the cell lines studied. The combined effect of radiation and heat produced greater cytotoxicity than predicted from the additive effects of the two individual treatment modalities alone. These results indicate that a combined treatment regimen of radiation plus hyperthermia (43 degrees, 1 hr) might be an important tool in maintaining a better local control of prostatic cancer

  19. Effect of Heat and Electricity Storage and Reliability on Microgrid Viability:A Study of Commercial Buildings in California and New York States

    Energy Technology Data Exchange (ETDEWEB)

    Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy; Coffey, Brian; Aki, Hirohisa

    2008-12-01

    In past work, Berkeley Lab has developed the Distributed Energy Resources Customer Adoption Model (DER-CAM). Given end-use energy details for a facility, a description of its economic environment and a menu of available equipment, DER-CAM finds the optimal investment portfolio and its operating schedule which together minimize the cost of meeting site service, e.g., cooling, heating, requirements. Past studies have considered combined heat and power (CHP) technologies. Methods and software have been developed to solve this problem, finding optimal solutions which take simultaneity into account. This project aims to extend on those prior capabilities in two key dimensions. In this research storage technologies have been added as well as power quality and reliability (PQR) features that provide the ability to value the additional indirect reliability benefit derived from Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid capability. This project is intended to determine how attractive on-site generation becomes to a medium-sized commercial site if economical storage (both electrical and thermal), CHP opportunities, and PQR benefits are provided in addition to avoiding electricity purchases. On-site electrical storage, generators, and the ability to seamlessly connect and disconnect from utility service would provide the facility with ride-through capability for minor grid disturbances. Three building types in both California and New York are assumed to have a share of their sensitive electrical load separable. Providing enhanced service to this load fraction has an unknown value to the facility, which is estimated analytically. In summary, this project began with 3 major goals: (1) to conduct detailed analysis to find the optimal equipment combination for microgrids at a few promising commercial building hosts in the two favorable markets of California and New York; (2) to extend the analysis capability of DER-CAM to include both heat and

  20. Energetic and exergetic efficiencies of coal-fired CHP (combined heat and power) plants used in district heating systems of China

    International Nuclear Information System (INIS)

    Liao, Chunhui; Ertesvåg, Ivar S.; Zhao, Jianing

    2013-01-01

    The efficiencies of coal-fired CHP (combined heat and power) plants used in the district heating systems of China were analyzed with a thermodynamic model in the Hysys program. The influences of four parameters were evaluated by the Taguchi method. The results indicated that the extraction steam flow rate and extraction steam pressure are the most important parameters for energetic and exergetic efficiencies, respectively. The relations between extraction steam flow rate, extraction steam pressure and the energetic and exergetic efficiencies were investigated. The energetic and exergetic efficiencies were compared to the RPES (relative primary energy savings) and the RAI (relative avoided irreversibility). Compared to SHP (separate heat and power) generation, the CHP systems save fuel energy when extraction ratio is larger than 0.15. In the analysis of RAI, the minimum extraction ratio at which CHP system has advantages compared with SHP varies between 0.25 and 0.6. The higher extraction pressure corresponds to a higher value. Two of the examined plants had design conditions giving RPES close to zero and negative RAI. The third had both positive RPES and RAI at design conditions. The minimum extraction ratio can be used as an indicator to design or choose CHP plant for a given district heating system. - Highlights: • Extraction flow rate and extraction pressure are the most important parameters. • The exergetic efficiency depends on the energy to exergy ratio and system boundary. • The minimum extraction ratio is a key indicator for CHP plants. • Program Hysys and Taguchi method are used in this research

  1. Measurement of heat treatment induced residual stresses by using ESPI combined with hole-drilling method

    Directory of Open Access Journals (Sweden)

    Jie Cheng

    2010-08-01

    Full Text Available In this study, residual stresses in heat treated specimen were measured by using ESPI (Electronic Speckle-Pattern Interferometry combined with the hole-drilling method. The specimen, made of SUS 304 austenitic stainless steel, was quenched and water cooled to room temperature. Numerical simulation using a hybrid FDM/FEM package was also carried out to simulate the heat treatment process. As a result, the thermal stress fields were obtained from both the experiment and the numerical simulation. By comparision of stress fields, results from the experimental method and numerical simulation well agreed to each other, therefore, it is proved that the presented experimental method is applicable and reliable for heat treatment induced residual stress measurement.

  2. High efficiency combined heat and power facilities - benefits and barriers

    International Nuclear Information System (INIS)

    Klein, M.

    2001-01-01

    There are important linkages between the economy, energy production, the environment and our health. Where thermal energy is needed, distributed Combined Heat and Power facilities, using gas turbines, reciprocating engines and future fuel cells can provide significant improvements to our long term mix of energy production. Local generation can also have benefits in security of energy supply and economic savings. This paper is intended to discuss the relevant air pollution and greenhouse gas emissions from modem CHP plants, the emission prevention and reduction methods available, and their operating experience and cost-effectiveness. Mention is made of recently constructed industrial and commercial plants, and institutional barriers to further development. Solutions described for these barriers include the need for more awareness of opportunities, improved access to the electricity grid, the proper design balance between thermal and electric for CHP systems rather than large combined cycles, improved corporate taxation incentives, and the assessment of all environmental and economic benefits when considering such cleaner sources in a restructured energy market. (author)

  3. Biomass from agriculture in small-scale combined heat and power plants - A comparative life cycle assessment

    International Nuclear Information System (INIS)

    Kimming, M.; Sundberg, C.; Nordberg, A.; Baky, A.; Bernesson, S.; Noren, O.; Hansson, P.-A.

    2011-01-01

    Biomass produced on farm land is a renewable fuel that can prove suitable for small-scale combined heat and power (CHP) plants in rural areas. However, it can still be questioned if biomass-based energy generation is a good environmental choice with regards to the impact on greenhouse gas emissions, and if there are negative consequences of using of agricultural land for other purposes than food production. In this study, a simplified life cycle assessment (LCA) was conducted over four scenarios for supply of the entire demand of power and heat of a rural village. Three of the scenarios are based on utilization of biomass in 100 kW (e) combined heat and power (CHP) systems and the fourth is based on fossil fuel in a large-scale plant. The biomass systems analyzed were based on 1) biogas production with ley as substrate and the biogas combusted in a microturbine, 2) gasification of willow chips and the product gas combusted in an IC-engine and 3) combustion of willow chips for a Stirling engine. The two first scenarios also require a straw boiler. The results show that the biomass-based scenarios reduce greenhouse gas emissions considerably compared to the scenario based on fossil fuel, but have higher acidifying emissions. Scenario 1 has by far the best performance with respect to global warming potential and the advantage of utilizing a byproduct and thus not occupying extra land. Scenario 2 and 3 require less primary energy and less fossil energy input than 1, but set-aside land for willow production must be available. The low electric efficiency of scenario 3 makes it an unsuitable option.

  4. Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

    Energy Technology Data Exchange (ETDEWEB)

    Kingston, T. [Gas Technology Inst., Des Plaines, IL (United States); Scott, S. [Gas Technology Inst., Des Plaines, IL (United States)

    2013-03-01

    Homebuilders are exploring more cost-effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads and found that the tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system, among other key findings.

  5. Treatment of PCR products with exonuclease I and heat-labile alkaline phosphatase improves the visibility of combined bisulfite restriction analysis

    International Nuclear Information System (INIS)

    Watanabe, Kousuke; Emoto, Noriko; Sunohara, Mitsuhiro; Kawakami, Masanori; Kage, Hidenori; Nagase, Takahide; Ohishi, Nobuya; Takai, Daiya

    2010-01-01

    Research highlights: → Incubating PCR products at a high temperature causes smears in gel electrophoresis. → Smears interfere with the interpretation of methylation analysis using COBRA. → Treatment with exonuclease I and heat-labile alkaline phosphatase eliminates smears. → The elimination of smears improves the visibility of COBRA. -- Abstract: DNA methylation plays a vital role in the regulation of gene expression. Abnormal promoter hypermethylation is an important mechanism of inactivating tumor suppressor genes in human cancers. Combined bisulfite restriction analysis (COBRA) is a widely used method for identifying the DNA methylation of specific CpG sites. Here, we report that exonuclease I and heat-labile alkaline phosphatase can be used for PCR purification for COBRA, improving the visibility of gel electrophoresis after restriction digestion. This improvement is observed when restriction digestion is performed at a high temperature, such as 60 o C or 65 o C, with BstUI and TaqI, respectively. This simple method can be applied instead of DNA purification using spin columns or phenol/chloroform extraction. It can also be applied to other situations when PCR products are digested by thermophile-derived restriction enzymes, such as PCR restriction fragment length polymorphism (RFLP) analysis.

  6. Combined heat and power in the Swedish district heating sector-impact of green certificates and CO2 trading on new investments

    International Nuclear Information System (INIS)

    Knutsson, David; Werner, Sven; Ahlgren, Erik O.

    2006-01-01

    Combined heat and power (CHP) has been identified by the EU administration as an important means of reducing CO 2 -emissions and increasing the energy efficiency. In Sweden, only about one third of the demand for district heat (DH) is supplied from CHP. This share could be significantly larger if the profitability of CHP generation increased. The objective of this study was to analyse the extent to which the profitability for investments in new CHP plants in the Swedish DH sector have changed thanks to the recently implemented trading schemes for green certificates (TGCs) and CO 2 emissions (TEPs). The analysis was carried out using a simulation model of the Swedish DH sector in which the profitability of CHP investments for all DH systems, with and without the two trading schemes applied, is compared. In addition, a comparison was made of the changes in CHP generation, CO 2 emissions, and operation costs if investments are made in the CHP plant shown to be most profitable in each system according to the model. The study shows that the profitability of investments in CHP plants increased significantly with the introductions of TGC and TEP schemes. If all DH utilities also undertook their most profitable CHP investments, the results indicate a major increase in power generation which, in turn, would reduce the CO 2 emissions from the European power sector by up to 13 Mton/year, assuming that coal condensing power is displaced

  7. Numerical investigation of nucleate pool boiling heat transfer

    Directory of Open Access Journals (Sweden)

    Stojanović Andrijana D.

    2016-01-01

    Full Text Available Multidimensional numerical simulation of the atmospheric saturated pool boiling is performed. The applied modelling and numerical methods enable a full representation of the liquid and vapour two-phase mixture behaviour on the heated surface, with included prediction of the swell level and heated wall temperature field. In this way the integral behaviour of nucleate pool boiling is simulated. The micro conditions of bubble generation at the heated wall surface are modelled by the bubble nucleation site density, the liquid wetting contact angle and the bubble grow time. The bubble nucleation sites are randomly located within zones of equal size, where the number of zones equals the nucleation site density. The conjugate heat transfer from the heated wall to the liquid is taken into account in wetted heated wall areas around bubble nucleation sites. The boiling curve relation between the heat flux and the heated wall surface temperature in excess of the saturation temperature is predicted for the pool boiling conditions reported in the literature and a good agreement is achieved with experimentally measured data. The influence of the nucleation site density on the boiling curve characteristic is confirmed. In addition, the influence of the heat flux intensity on the spatial effects of vapour generation and two-phase flow are shown, such as the increase of the swell level position and the reduced wetting of the heated wall surface by the heat flux increase. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018 i br. OI-174014

  8. [Effect of heat-reinforcing needling combined with rehabilitation training on the motor function of ischemic stroke patients].

    Science.gov (United States)

    Zhang, Ning-xia; Liu, Gui-zhen; Huang, Tai-quan; Li, Wei-jiang; Luo, Jia-qi; Liu, Wei-wei; Huang, Yong; Wang, Ai-min

    2009-12-01

    To observe the therapeutic effect of heat-reinforcing needling combined with modem rehabilitation training on the motor function of ischemic stroke patients. Fifty case of ischemic stroke patients were randomly divided into rehabilitation (Rehab, n=40) and acupuncture (Acup) + Rehab (n=40) groups. Heat-reinforcing needling was applied to Jianyu (LI 15), Quchi (LI 11), Hegu (LI 14), Zusanli (ST 36), Yanglingquan (GB 34), Yinlingquan (SP 9) and Sanyinjiao (SP 6), once daily for 3 weeks. Rehabilitation training including healthy limb and joint movement was conducted, once daily for 3 weeks. The patient's neurological impairment degree and the motor function (Fugl-Meyer index) were evaluated before and after the treatment. After the treatment, of the each 40 cases in Rehab and Acup + Rehab groups, 10 (25.0%) and 17 (42.5%) experienced marked improvement in their symptoms, 17 (42.5%) and 18 (45.0%) had improvement, 13 (32.5%) and 5 (12.5%) failed, with the effective rates being 67.5% and 87.5% respectively. The therapeutic effect of Acup + Rehab group was markedly superior to that of Rehab group (P0.05). After the treatment, the scores of neurological impairment degree of two groups both decreased significantly (PRehab group was significantly lower than that of Rehab group (PRehab group were obviously higher than those of Rehab group (Pstroke patients.

  9. Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J.; Jiang, Y. [Southern Medical University, Nanfang Hospital, Department of Anesthesia, Guangzhou, China, Department of Anesthesia, Nanfang Hospital, Southern Medical University, Guangzhou (China); Tang, Y.; Chen, B. [Guangzhou General Hospital of Guangzhou Military Command, Department of Intensive Care Unit, Guangzhou, China, Department of Intensive Care Unit, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou (China); Sun, X. [Laboratory of Traditional Chinese Medicine Syndrome, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou (China); Su, L.; Liu, Z. [Guangzhou General Hospital of Guangzhou Military Command, Department of Intensive Care Unit, Guangzhou, China, Department of Intensive Care Unit, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou (China)

    2013-06-25

    Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries.

  10. Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

    International Nuclear Information System (INIS)

    Tang, J.; Jiang, Y.; Tang, Y.; Chen, B.; Sun, X.; Su, L.; Liu, Z.

    2013-01-01

    Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries

  11. Design optimization and sensitivity analysis of a biomass-fired combined cooling, heating and power system with thermal energy storage systems

    International Nuclear Information System (INIS)

    Caliano, Martina; Bianco, Nicola; Graditi, Giorgio; Mongibello, Luigi

    2017-01-01

    Highlights: • A novel operation strategy for biomass-fired combined cooling, heating and power system is presented. • A design optimization of the system is conducted. • The effects of variation of the incentive for the electricity generation are evaluated. • The effects of the variation of the absorption chiller size and the thermal energy storage system one are evaluated. • The inclusion of a cold storage system into the combined cooling, heating and power system is also analyzed. - Abstract: In this work, an operation strategy for a biomass-fired combined cooling, heating and power system, composed of a cogeneration unit, an absorption chiller, and a thermal energy storage system, is formulated in order to satisfy time-varying energy demands of an Italian cluster of residential multi-apartment buildings. This operation strategy is adopted for performing the economical optimization of the design of two of the devices composing the combined cooling, heating and power system, namely the absorption chiller and the storage system. A sensitivity analysis is carried out in order to evaluate the impact of the incentive for the electricity generation on the optimized results, and also to evaluate, separately, the effects of the variation of the absorption chiller size, and the effects of the variation of the thermal energy storage system size on the system performance. In addition, the inclusion into the system of a cold thermal energy storage system is analyzed, as well, assuming different possible values for the cold storage system cost. The results of the sensitivity analysis indicate that the most influencing factors from the economical point of view are represented by the incentive for the electricity generation and the absorption chiller power. Results also show that the combined use of a thermal energy storage and of a cold thermal energy storage during the hot season could represent a viable solution from the economical point of view.

  12. Superficial basal cell carcinoma: A comparison of superficial only subtype with superficial combined with other subtypes by age, sex and anatomic site in 3150 cases.

    Science.gov (United States)

    Pyne, John H; Myint, Esther; Barr, Elizabeth M; Clark, Simon P; David, Michael; Na, Renua; Hou, Ruihang

    2017-08-01

    Basal cell carcinoma (BCC) may present as superficial subtype alone (sBCC) or superficial combined with other subtypes. The objective of this study was to compare sBCC without or with other BCC subtypes by age, sex and anatomic site. We retrospectively collected superficial BCC with the above characteristics from an Australian center during 2009 to 2014. We recorded 1528 sBCC and 1622 superficial BCC combined with other BCC subtype cases. Males numbered 2007 and females 1140. On males, head sites (forehead, cheek, nose and ear combined) compared to limb plus trunk sites displayed a higher incidence of superficial BCC combined with either nodular and or aggressive BCC subtypes (OR 13.15 CI 95% 8.9-19.5 P < .0001). On females a similar comparison also found a higher incidence of superficial BCC combined with solid subtype BCC on head sites compared to trunk and limb sites (OR 9.66 CI 95% 5.8-16.1 P < .0001). Superficial BCC alone is more likely on younger females on trunk and limb sites. Small partial biopsies reported as sBCC may miss other BCC subtypes present with higher risk on facial sites for males and females. Males had smaller proportions of superficial only subtype BCC on facial and ear sites compared to females. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Sizing Combined Heat and Power Units and Domestic Building Energy Cost Optimisation

    OpenAIRE

    Dongmin Yu; Yuanzhu Meng; Gangui Yan; Gang Mu; Dezhi Li; Simon Le Blond

    2017-01-01

    Many combined heat and power (CHP) units have been installed in domestic buildings to increase energy efficiency and reduce energy costs. However, inappropriate sizing of a CHP may actually increase energy costs and reduce energy efficiency. Moreover, the high manufacturing cost of batteries makes batteries less affordable. Therefore, this paper will attempt to size the capacity of CHP and optimise daily energy costs for a domestic building with only CHP installed. In this paper, electricity ...

  14. Passive Decay Heat Removal Strategy of Integrated Passive Safety System (IPSS) for SBO-combined Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Ho; Chang, Soon Heung; Jeong, Yong Hoon [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-10-15

    The weak points of nuclear safety would be in outmoded nuclear power plants like the Fukushima reactors. One of the systems for the safety enhancement is integrated passive safety system (IPSS) proposed after the Fukushima accidents. It has the five functions for the prevention and mitigation of a severe accident. Passive decay heat removal (PDHR) strategy using IPSS is proposed for coping with SBO-combined accidents in this paper. The two systems for removing decay heat before core-melt were applied in the strategy. The accidents were simulated by MARS code. The reference reactor was OPR1000, specifically Ulchin-3 and 4. The accidents included loss-of-coolant accidents (LOCA) because the coolant losses could be occurred in the SBO condition. The examples were the stuck open of PSV, the abnormal open of SDV and the leakage of RCP seal water. Also, as LOCAs with the failure of active safety injection systems were considered, various LOCAs were simulated in SBO. Based on the thermal hydraulic analysis, the probabilistic safety analysis was carried out for the PDHR strategy to estimate the safety enhancement in terms of the variation of core damage frequency. AIMS-PSA developed by KAERI was used for calculating CDF of the plant. The IPSS was applied in the PDHR strategy which was developed in order to cope with the SBO-combined accidents. The estimation for initiating SGGI or PSIS was based on the pressure in RCS. The simulations for accidents showed that the decay heat could be removed for the safety duration time in SBO. The increase of safety duration time from the strategy provides the increase of time for the restoration of AC power.

  15. Combined heat and power and thermally insulating measures in residential housing stock; Kraft-Waerme-Kopplung und Daemmmassnahmen im Wohngebaeudebestand

    Energy Technology Data Exchange (ETDEWEB)

    Buller, Michael [Gas- und Waerme-Institut Essen e.V., Essen (Germany)

    2013-02-15

    The author of the contribution under consideration reports on the economic, ecologic and primary energetic potential of micro-combined heat and power (micro-CHP) in the residential housing stock under consideration of possible correlations between CHP and thermally insulating measures.

  16. Nuclear Energy Center Site Survey, 1975. Part I. Summary and conclusions

    International Nuclear Information System (INIS)

    1976-01-01

    The Nuclear Energy Center Site Survey is a study of a potential siting approach for projected power and fuel-cycle facilities that would cluster sizable groups of such facilities on a relatively small number of sites, as contrasted with current dispersed siting practices. Three basic types of nuclear energy centers (NECs) are considered: power-plant centers, involving ten to forty units of 1200-megawatt electric capacity each; fuel-cycle centers, involving fuel reprocessing plants, mixed-oxide fuel fabrication facilities, and high-level and transuranic radioactive waste management facilities, with a capacity corresponding to the fuel throughput of power plants with a total capacity of approximately 50,000 to 300,000 MWe; and combined centers, containing both power plants and fuel cycle facilities in representative possible combinations. Included among the principal issues considered in evaluation of feasibility of nuclear energy centers are dissipation of the waste heat from the power-generating facilities; transmission system design, reliability, and economics; radiological impact; and environmental impact

  17. Simulation of a solar assisted combined heat pump – Organic rankine cycle system

    International Nuclear Information System (INIS)

    Schimpf, Stefan; Span, Roland

    2015-01-01

    Highlights: • Addition of an ORC to a solar thermal and ground source heat pump system. • Reverse operation of the scroll compressor in ORC mode. • Annual simulations for application in a single-family house at three locations. • By introducing the ORC the net electricity demand is reduced by 1–9%. • Over the lifetime of the system savings can cover additional investments. - Abstract: A novel solar thermal and ground source heat pump system that harnesses the excess heat of the collectors during summer by an Organic Rankine Cycle (ORC) is simulated. For the ORC the heat pump process is reversed. In this case the scroll compressor of the heat pump runs as a scroll expander and the working fluid is condensed in the ground heat exchanger. Compared to a conventional solar thermal system the only additional investments for the combined system are a pump, valves and upgraded controls. The goal of the study is to simulate and optimize such a system. A brief overview of the applied models and the evolutionary algorithm for the optimization is given. A system with 12 m 2 of flat plate collectors installed in a single family house is simulated for the locations Ankara, Denver and Bochum. The ORC benefits add up to 20–140 kW h/a, which reduces the net electricity demand of the system by 1–9%. Overall 180–520 € are saved over a period of 20 years, which can be enough to cover the additional investments

  18. Influence of ambient temperatures on performance of a CO2 heat pump water heating system

    International Nuclear Information System (INIS)

    Yokoyama, Ryohei; Shimizu, Takeshi; Ito, Koichi; Takemura, Kazuhisa

    2007-01-01

    In residential applications, an air-to-water CO 2 heat pump is used in combination with a domestic hot water storage tank, and the performance of this system is affected significantly not only by instantaneous ambient air and city water temperatures but also by hourly changes of domestic hot water consumption and temperature distribution in the storage tank. In this paper, the performance of a CO 2 heat pump water heating system is analyzed by numerical simulation. A simulation model is created based on thermodynamic equations, and the values of model parameters are estimated based on measured data for existing devices. The calculated performance is compared with the measured one, and the simulation model is validated. The system performance is clarified in consideration of seasonal changes of ambient air and city water temperatures

  19. On the Partitioning of Wall Heat Flux in Subcooled Flow Boiling

    International Nuclear Information System (INIS)

    Chu, In-Cheol; Hoang, Nhan Hien; Euh, Dong-Jin; Song, Chul-Hwa

    2015-01-01

    This region has been treated successfully by two-fluid model coupled with a population balance model or interfacial area transport equation (IATE). The second region is near-wall heat transfer which has been commonly described by a wall heat flux partitioning model coupled with models of nucleation site density (NSD), bubble departure diameter and bubble release frequency. Since the phase change process in the near-wall heat transfer is really complex, comprising different heat transfer mechanisms, bubble dynamics, bubble nucleation and thermal response of heated surface, the modeling of the second region is still a great challenge despite intensive efforts. Numerous models and correlations have been proposed to aim for computing the near-wall heat transfer. The models of nucleation site density, bubble departure diameter and bubble release frequency are used to quantify these components. The models closely related to each other. The heat flux partitioning model controls the wall and liquid temperatures. Then, it turns to control the boiling parameters, i.e. nucleation site density, bubble departure diameter and bubble release frequency. In this study, the partitioning of wall heat flux is taken into account. The existing issues occurred with previous models of the heat flux partitioning are pointed out and then a new model which considers the heat transfer caused by evaporation of superheated liquid at bubble boundary and the actual period of transient conduction term is formulated. The new model is then validated with a collected experimental database. This paper presented a new heat flux partitioning model in which the heat transfer by evaporation of the superheated liquid at the bubble boundary and the active period of the transient conduction were considered. The new model was validated with the experimental data of the subcooled flow boiling of water obtained by Phillips

  20. Integrated application of combined cooling, heating and power poly-generation PV radiant panel system of zero energy buildings

    Science.gov (United States)

    Yin, Baoquan

    2018-02-01

    A new type of combined cooling, heating and power of photovoltaic radiant panel (PV/R) module was proposed, and applied in the zero energy buildings in this paper. The energy system of this building is composed of PV/R module, low temperature difference terminal, energy storage, multi-source heat pump, energy balance control system. Radiant panel is attached on the backside of the PV module for cooling the PV, which is called PV/R module. During the daytime, the PV module was cooled down with the radiant panel, as the temperature coefficient influence, the power efficiency was increased by 8% to 14%, the radiant panel solar heat collecting efficiency was about 45%. Through the nocturnal radiant cooling, the PV/R cooling capacity could be 50 W/m2. For the multifunction energy device, the system shows the versatility during the heating, cooling and power used of building utilization all year round.

  1. A site-scale model for fluid and heat flow in the unsaturated zone of Yucca Mountain, Nevada

    Science.gov (United States)

    Wu, Yu-Shu; Haukwa, Charles; Bodvarsson, G. S.

    1999-05-01

    A three-dimensional unsaturated-zone numerical model has been developed to simulate flow and distribution of moisture, gas and heat at Yucca Mountain, Nevada, a potential repository site for high-level radioactive waste. The model takes into account the simultaneous flow dynamics of liquid water, vapor, air and heat in the highly heterogeneous, fractured porous rock in the unsaturated zone (UZ). This model is intended for use in the prediction of the current and future conditions in the UZ so as to aid in the assessment of the system performance of the proposed repository. The modeling approach is based on a mathematical formulation of coupled multiphase, multicomponent fluid and heat flow through porous and fractured rock. Fracture and matrix flow is treated using both dual-permeability and effective-continuum modeling approaches. The model domain covers a total area of approximately 43 km 2, and uses the land surface and the water table as its top and bottom boundaries. In addition, site-specific data, representative surface infiltration, and geothermal conditions are incorporated into the model. The reliability and accuracy of the model have been the subject of a comprehensive model calibration study, in which the model was calibrated against measured data, including liquid saturation, water potential and temperature. It has been found that the model is generally able to reproduce the overall system behavior at Yucca Mountain with respect to moisture profiles, pneumatic pressure variations in different geological units, and ambient geothermal conditions.

  2. Impact of heated waters on water quality and macroinvertebrate community in the Narew River (Poland

    Directory of Open Access Journals (Sweden)

    Krolak Elzbieta

    2017-07-01

    Full Text Available The effect of heated waters from coal-burning power stations on the water parameters and the occurrence of macroinvertebrates depends on the individual characteristics of the river to which the heated waters are discharged. The objective of the study was to assess the impact of heated water from the Ostrołęka Power Station on selected water properties and the macroinvertebrate community in the Narew River. Samples were collected in years: 2013-2016 along two river stretches: upstream and downstream of the canal. The water temperature was higher and the oxygen concentrations were lower at the downstream sites compared to the upstream sites of the canal. The values of conductivity, concentrations of nitrates, phosphates, chlorides and calcium were similar at the sampling sites. A total of 33 families of macrozoobenthos were found. The numbers of families were positively correlated with the temperature and conductivity and negatively correlated with oxygen. The heated waters were found to have no effect on the Shannon-Wiener diversity index. The inflow of heated waters increased the percentage of Gammaridae, represented by species Dikerogammarus haemobaphes (Eichwald, 1841 and decreased the percentage of Chironomidae. The presence of the thermophilous bivalve Sinanodonta woodiana (Lea, 1934 was noted downstream of the canal.

  3. An experimental investigation of heat transfer enhancement in minichannel: Combination of nanofluid and micro fin structure techniques

    DEFF Research Database (Denmark)

    Zhang, Ji; Diao, Yanhua; Zhao, Yaohua

    2017-01-01

    This work experimentally studied the single-phase heat transfer and pressure drop characteristics by using two heat transfer enhancement techniques (micro fin structure and nanofluids) in multiport minichannel flat tube (MMFT). MMFT consisted of numerous parallel rectangular minichannels...... and is widely used in industry as the heat transfer unit of a heat exchanger. Firstly, the enhanced heat transfer performances by individually using one enhancement technique were investigated by testing Nusselt number, friction factor and performance evaluation criterion (PEC). In this section, five MMFTs...... with different micro fin numbers (N = 0, 1, 2, 3 and 4) and nanofluids with three volume concentrations (φ = 0.005%, 0.01% and 0.1%) were used as test sections and working fluids respectively. Secondly, the experiments using two combined enhancement technique were performed. By using conjunctively two...

  4. Experimental investigation on Heat Transfer Performance of Annular Flow Path Heat Pipe

    International Nuclear Information System (INIS)

    Kim, In Guk; Kim, Kyung Mo; Jeong, Yeong Shin; Bang, In Cheol

    2015-01-01

    Mochizuki et al. was suggested the passive cooling system to spent nuclear fuel pool. Detail analysis of various heat pipe design cases was studied to determine the heat pipes cooling performance. Wang et al. suggested the concept PRHRS of MSR using sodium heat pipes, and the transient performance of high temperature sodium heat pipe was numerically simulated in the case of MSR accident. The meltdown at the Fukushima Daiichi nuclear power plants alarmed to the dangers of station blackout (SBO) accident. After the SBO accident, passive decay heat removal systems have been investigated to prevent the severe accidents. Mochizuki et al. suggested the heat pipes cooling system using loop heat pipes for decay heat removal cooling and analysis of heat pipe thermal resistance for boiling water reactor (BWR). The decay heat removal systems for pressurized water reactor (PWR) were suggested using natural convection mechanisms and modification of PWR design. Our group suggested the concept of a hybrid heat pipe with control rod as Passive IN-core Cooling System (PINCs) for decay heat removal for advanced nuclear power plant. Hybrid heat pipe is the combination of the heat pipe and control rod. In the present research, the main objective is to investigate the effect of the inner structure to the heat transfer performance of heat pipe containing neutron absorber material, B 4 C. The main objective is to investigate the effect of the inner structure in heat pipe to the heat transfer performance with annular flow path. ABS pellet was used instead of B 4 C pellet as cylindrical structures. The thermal performances of each heat pipes were measured experimentally. Among them, concentric heat pipe showed the best performance compared with others. 1. Annular evaporation section heat pipe and annular flow path heat pipe showed heat transfer degradation. 2. AHP also had annular vapor space and contact cooling surface per unit volume of vapor was increased. Heat transfer coefficient of

  5. Emission operational strategy for combined cooling, heating, and power systems

    International Nuclear Information System (INIS)

    Fumo, Nelson; Mago, Pedro J.; Chamra, Louay M.

    2009-01-01

    Integrated Energy Systems (IES), as technology that use thermal activated components to recover waste heat, are energy systems that offer key solution to global warming and energy security through high overall energy efficiency and better fuel use. Combined Cooling, Heating, and Power (CCHP) Systems are IES that use recovered thermal energy from the prime mover to produce heating and cooling for the building. The CCHP operational strategy is critical and it has to be considered in a well designed system since it defines the ultimate goal for the benefits expected from the system. One of the most common operational strategies is the cost-oriented strategy, which allows the system to operate at the lowest cost. A primary energy strategy (PES) optimizes energy consumption instead of cost. However, as a result of the worldwide concern about global warming, projects that target reduction of greenhouse gas (GHG) emissions have gained a lot of interest. Therefore, for a CCHP system, an emission strategy (ES) would be an operational strategy oriented to minimize emission of pollutants. In this study, the use of an ES is proposed for CCHP systems targeted to reduce emission of pollutants. The primary energy consumption (PEC) reduction and carbon dioxide (CO 2 ) emission reduction obtained using the proposed ES are compared with results obtained from the use of a PES. Results show that lower emission of CO 2 is achieved with the ES when compared with the PES, which prove the advantage of the ES for the design of CCHP systems targeted to emissions reduction.

  6. Towards predictive scenario simulations combining LH, ICRH and ECRH heating

    International Nuclear Information System (INIS)

    Basiuk, V.; Artaud, J.F.; Becoulet, A.; Eriksson, L.G.; Hoang, G.T.; Huysmans, G.; Imbeaux, F.; Litaudon, X.; Mazon, D.; Passeron, C.; Peysson, Y.

    2003-01-01

    Reliable predictive simulations, combining current, heat and matter transport equation with a 2D equilibrium allowing diagnostic reconstruction such as Faraday angle and MSE angle are of a great interest for existing and future tokamak. The Cronos code with its various power deposition codes (Delphine, Rema, Pion) is a powerful tool to prepare such scenario in a reasonable CPU time (a few hours, for one minute plasma discharge). An example of such advanced scenario, with a negative seed of current at the center of the discharge is shown in this paper. It allows also testing new concept of feedback control, which will be directly implemented on the new real-time network of Tore-Supra. In this concept, the algorithm as to find itself the best and safe way to reach enhance performance (i.e. best plasma fusion power D-D) using different actuators (injected power,...). On this paper, we will focus on a simple example where the initial and final states are known and we will show why a steady state tokamak allowing long pulse operation is necessary for such control. (authors)

  7. Modeling the heat transfer problem for the novel combined cryosurgery and hyperthermia system.

    Science.gov (United States)

    Zhao, Gang; Bai, Xue-Fei; Luo, Da-Wei; Gao, Da-Yong

    2006-01-01

    A multidimensional, finite element analysis (FEA) for the freezing, holding, rewarming and heating processes of biological tissues during the cryosurgery process of the new Combined Cryosurgery/Hyperthermia System is presented to theoretically test its validity. The tissues are treated as nonideal materials freezing over a temperature range, and the thermophysical properties of which are temperature dependent. The enthalpy method is applied to solve the highly nonlinear problem. It was found that when the same boundary condition and the same target tissue presented, the novel Cryosurgery/Hyperthermia System could supply the target tissue an approximative cooling rate, a much lower minimal temperature, a much greater warming rate, and a much greater thermal gradients compared with that of the simplified Endocare system. The numerical simulation indicates that the novel combined cryosurgery and hyperthermia system can provide an excellent curative effect in the corresponding cryotherapy. And the most attractive feature of this FEA framework is that it can be easily mastered by the surgeon without in-depth theory of heat transfer to analyze the cryosurgery process beforehand due to the friendly GUI (graphical user interface) of Ansys software.

  8. Comparative and Combinative Study of Urban Heat island in Wuhan City with Remote Sensing and CFD Simulation

    Directory of Open Access Journals (Sweden)

    Zhuang Yu

    2008-10-01

    Full Text Available Urban heat islands are one of the most critical urban environment heat problems. Landsat ETM+ satellite data were used to investigate the land surface temperature and underlying surface indices such as NDVI and NDBI. A comparative study of the urban heat environment at different scales, times and locations was done to verify the heat island characteristics. Since remote sensing technology has limitations for dynamic flow analysis in the study of urban spaces, a CFD simulation was used to validate the improvement of the heat environment in a city by means of wind. CFD technology has its own shortcomings in parameter setting and verification, while RS technology is helpful to remedy this. The city of Wuhan and its climatological condition of being hot in summer and cold in winter were chosen to verify the comparative and combinative application of RS with CFD in studying the urban heat island.

  9. Combined natural convection and surface radiation in the annular region between a volumetrically heated inner tube and a finite conducting outer tube

    International Nuclear Information System (INIS)

    Gianoulakis, S.; Klein, D.E.

    1993-01-01

    Buoyancy-driven natural-convection heat transfer in enclosures has been the subject of considerable research with applications to electronic packaging, solar collectors, and shipping containers for spent nuclear fuel. A numerical study has been carried out to predict combined natural-convection and radiation heat transfer in the annular region between concentric tubes. The inner tube was volumetrically heated. Both tubes were of finite conductance. The surfaces of the annular region were diffuse and gray. The gas in the annulus was assumed to be nonparticipating. A newly developed hybrid finite element finite difference method was used for the study. This method combines finite element discretization of geometries with finite difference discretized solution procedures for the governing differential equations. This study examined the effects of surface radiative properties and material conductivities on the temperature and velocity fields and on local heat transfer rates. Fluid Raleigh numbers ranging from 10 3 to 10 7 , ratios of solid to fluid region thermal conductivities ranging from 10 to 10 4 , and surface total hemispherical emissivities ranging from 0.0 to 1.0 were examined in this study. It was found that the heat transfer across the annulus was dominated by conduction and radiation for the lower Raleigh number flows. As the fluid Raleigh number increased, convection became a primary mode of heat transfer. As the surface emissivity was increased in the annulus, the average Nusselt number on the inner tube surface decreased

  10. Studies on Single-phase and Multi-phase Heat Pipe for LED Panel for Efficient Heat Dissipation

    Science.gov (United States)

    Vyshnave, K. C.; Rohit, G.; Maithreya, D. V. N. S.; Rakesh, S. G.

    2017-08-01

    The popularity of LED panel as a source of illumination has soared recently due to its high efficiency. However, the removal of heat that is produced in the chip is still a major challenge in its design since this has an adverse effect on its reliability. If high junction temperature develops, the colour of the emitted light may diminish over prolonged usage or even a colour shift may occur. In this paper, a solution has been developed to address this problem by using a combination of heat pipe and heat fin technology. A single-phase and a two-phase heat pipes have been designed theoretically and computational simulations carried out using ANSYS FLUENT. The results of the theoretical calculations and those obtained from the simulations are found to be in agreement with each other.

  11. Response of melanoma to heat and radiation therapy--a review of the literature and experience from The Prince of Wales Hospital, Sydney.

    Science.gov (United States)

    Mameghan, H; Knittel, T

    1988-11-07

    Our review of the literature indicates that radiotherapy and/or heat therapy can provide local control of recurrent or metastatic melanoma in a large proportion of patients. This has undoubted value in the local palliation of symptoms and, in the absence of disseminated disease, can be curative. At The Prince of Wales Hospital, Sydney, we have studied the response of melanoma lesions to heat and radiation therapy and have assessed the reaction in the adjacent normal skin. Thirty-two melanoma lesions that were measurable in 12 patients received radiotherapy and heat therapy in different combinations and dose schedules (15 lesions received radiotherapy alone, six lesions received heat therapy alone, and 11 lesions received combined radiation and heat therapy). The acute normal skin reaction was compared between lesions that received single modality radiation or heat therapy and those that received the combination of heat and radiation therapy. A moderate or severe reaction developed at six of the 21 sites that were treated by a single modality, and at four of the 11 sites that received combined heat and radiation therapy (P = 0.7), and all healed within a few days. Evaluation of the melanoma response to therapy was possible only in 26 of the 32 lesions that were treated because two patients died soon after therapy and the response of their six lesions was not evaluable. A complete response occurred in 14 (54%) of 26 lesions and a partial response occurred in 10 (38%) of 26 lesions. The objective response by treatment modality was 10 of 15 lesions for radiotherapy, six of six lesions for heat therapy and eight of 11 lesions for both therapies combined. We conclude that radiotherapy and heat therapy, separately or combined, produce acceptably-low damage to normal tissue and highly-satisfactory local control of melanoma.

  12. Thermoeconomic Analysis of Hybrid Power Plant Concepts for Geothermal Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2014-07-01

    Full Text Available We present a thermo-economic analysis for a low-temperature Organic Rankine Cycle (ORC in a combined heat and power generation (CHP case. For the hybrid power plant, thermal energy input is provided by a geothermal resource coupled with the exhaust gases of a biogas engine. A comparison to alternative geothermal CHP concepts is performed by considering variable parameters like ORC working fluid, supply temperature of the heating network or geothermal water temperature. Second law efficiency as well as economic parameters show that hybrid power plants are more efficient compared to conventional CHP concepts or separate use of the energy sources.

  13. Heat Transfer Computations of Internal Duct Flows With Combined Hydraulic and Thermal Developing Length

    Science.gov (United States)

    Wang, C. R.; Towne, C. E.; Hippensteele, S. A.; Poinsatte, P. E.

    1997-01-01

    This study investigated the Navier-Stokes computations of the surface heat transfer coefficients of a transition duct flow. A transition duct from an axisymmetric cross section to a non-axisymmetric cross section, is usually used to connect the turbine exit to the nozzle. As the gas turbine inlet temperature increases, the transition duct is subjected to the high temperature at the gas turbine exit. The transition duct flow has combined development of hydraulic and thermal entry length. The design of the transition duct required accurate surface heat transfer coefficients. The Navier-Stokes computational method could be used to predict the surface heat transfer coefficients of a transition duct flow. The Proteus three-dimensional Navier-Stokes numerical computational code was used in this study. The code was first studied for the computations of the turbulent developing flow properties within a circular duct and a square duct. The code was then used to compute the turbulent flow properties of a transition duct flow. The computational results of the surface pressure, the skin friction factor, and the surface heat transfer coefficient were described and compared with their values obtained from theoretical analyses or experiments. The comparison showed that the Navier-Stokes computation could predict approximately the surface heat transfer coefficients of a transition duct flow.

  14. Comparison of indoor air distribution and thermal environment for different combinations of radiant heating systems with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Fang, Lei; Olesen, Bjarne W.

    2018-01-01

    A hybrid system with a radiant heating system and a mechanical ventilation system, which is regarded as an advanced heating, ventilation and air-conditioning (HVAC) system, has been applied in many modern buildings worldwide. To date, almost no studies focused on comparative analysis of the indoor...... air distribution and the thermal environment for all combinations of radiant heating systems with mechanical ventilation systems. Therefore, in this article, the indoor air distribution and the thermal environment were comparatively analyzed in a room with floor heating (FH) or ceiling heating (CH......) and mixing ventilation (MV) or displacement ventilation (DV) when the supply air temperature ranged from 15.0°C to 19.0°C. The results showed that the temperature effectiveness values were 1.05–1.16 and 0.95–1.02 for MV+ FH and MV+ CH, respectively, and they were 0.78–0.91 and 0.51–0.67 for DV + FH and DV...

  15. Tests of a robust eddy correlation system for sensible heat flux

    Science.gov (United States)

    Blanford, J. H.; Gay, L. W.

    1992-03-01

    Sensible heat flux estimates from a simple, one-propeller eddy correlation system (OPEC) were compared with those from a sonic anemometer eddy correlation system (SEC). In accordance with similarity theory, the performance of the OPEC system improved with increasing height of the sensor above the surface. Flux totals from the two systems at sites with adequate fetch were in excellent agreement after frequency response corrections were applied. The propeller system appears suitable for long periods of unattended measurement. The sensible heat flux measurements can be combined with net radiation and soil heat flux measurements to estimate latent heat as a residual in the surface energy balance.

  16. Efficiency of Gamma Radiation Alone or In Combination With Heat Stress on Metal Contents of Parents and First Generation of Males of The Cotton Leaf Worm Spodoptera Littoralis

    International Nuclear Information System (INIS)

    El-Degwi, M.S.; Alm El-Din, M.M.S.; Hazaa, M.A.M.

    2011-01-01

    The main objective of the present investigation was to determine the influence of gamma radiation either alone or in combination with heat on the contents and concentration of elements detected in the whole body tissue of male parents and F1 generation of Spodoptera littoralis treated as full grown pupae. The doses applied were 75, 100 and 150 Gy. The data revealed the presence of eight elements in parents and F1 generation exposed to different heat stress (27±2, 33 and 37 degree C and P and Mg were the major contents. The obtained data indicated also that there were no differences in the composition of individual elements between male parents and male F1 generation. There were differences in relative concentration which depends on irradiation dose. The combination treatments were effective on elements concentration. The total concentration of light elements of male parents and F1 generation was increased by increasing the radiation dose. In the contrary, the concentration of heavy element was decreased by increasing the radiation dose. It could be concluded that gamma radiation and/or heat was effective on elements concentrations in adult body of male parents and F1 generation of Spodoptera littoralis which served as biological indicator of normal metabolic pathways and/or biological activity.

  17. ICRF heating analysis on ASDEX plasmas

    International Nuclear Information System (INIS)

    Itoh, Sanae; Itoh, Kimitaka; Fukuyama, Atsushi; Morishita, Takayuki; Steinmetz, K.; Noterdaeme, J.-M.

    1988-01-01

    ICRF (ion cyclotron range of frequencies) waves heating in an ASDEX tokamak are analyzed. The excitation, propagation and absorption are studied by using a global wave code. This analysis is combined with a Fokker-Planck code. The waveform in the plasma, the loading resistance and the reactance of the antenna are calculated for both the minority ion heating and the second harmonic resonance heating. Attention is given to the change of the antenna loading associated with the L/H transition. Optimum conditions for the loading are discussed. In the minority heating case, the tail generation and thermalization are analyzed. Spatial profiles of the tail-ion temperature and the power transferred to the bulk electrons and ions are obtained. Central as well as off-central heating cases are investigated. The effect of the reactive electric field is discussed in connection with rf losses and impurity production. (author)

  18. Experimental investigation of nucleate boiling on heated surfaces under subcooled conditions

    International Nuclear Information System (INIS)

    Schneider, C.; Hampel, R.; Traichel, A.; Hurtado, A.; Meissner, S.; Koch, E.

    2011-01-01

    In case of an accident at pressurized water reactors (PWR), critical boiling conditions can appear at the transition from bubble- to film boiling. During full power operation, heat transfer phenomena of sub cooled nucleate boiling occur on the surface of the fuel rods. To investigate the microscopic processes in nucleate boiling, a test facility with optical measuring methods was constructed. This allows analyzing the effects on a single bubble system at different parameters. For the generation of nucleate boiling, an optically transparent, electrically conductive coating was applied as a heating surface on a borosilicate substrate. The so-called ITO (Indium-Tin-Oxide) coating with a sheet resistance of 20 ohms enables an electrical heating at an optical transparent surface. These properties are prerequisites for the study of microscopic phenomena in the bubble formation with optical coherence tomography (OCT). OCT, generally used in medical diagnostics, is an imaging modality providing cross sectional and volumetric high resolution images. To make sure that the bubble formation takes place at a specific site, artificial nucleation sites in form of micro cavity will be inserted into the surface. Furthermore a small test facility was constructed to dedicate the wall temperature of a heated metal foil during subcooled boiling in non degassed water, which is the content of this paper. (author)

  19. Pre-Feasibility Analysis of Pellet Manufacturing on the Former Loring Air Force Base Site. A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America's Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites

    Energy Technology Data Exchange (ETDEWEB)

    Hunsberger, R.; Mosey, G.

    2014-04-01

    The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response, in accordance with the RE-Powering America's Lands initiative, engaged the U.S. Department of Energy's (DOE) National Renewable Energy Laboratory (NREL) to conduct feasibility studies to assess the viability of developing renewable energy generating facilities on contaminated sites. This site, in Limestone, Maine -- formerly the location of the Loring Air Force Base but now owned by the Aroostook Band of Micmac -- was selected for the potential to produce heating pellets from woody feedstock. Biomass was chosen as the renewable energy resource to evaluate based on abundant woody-biomass resources available in the area. NREL also evaluates potential savings from converting existing Micmac property from oil-fired heating to pellet heating.

  20. Effects of heat flux on dropwise condensation on a superhydrophobic surface

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Kyung Won; Park, Hyun Sun; Moriyama, Kiyofumi [POSTECH, Pohang (Korea, Republic of); Kim, Dong Hyun [KAERI, Daejeon (Korea, Republic of); Jo, Hang Jin [University of Wisconsin-Madison, Wisconsin (United States); Kim, Moo Hwan [KINS, Daejeon (Korea, Republic of)

    2016-05-15

    The condensation heat transfer efficiencies of superhydrophobic surfaces that have ∼160.deg. contact angle under atmospheric conditions were investigated experimentally. The departing diameter and the contact angle hysteresis of droplets were measured by capturing front and tilted side views of condensation phenomena with a high speed camera and an endoscope, respectively. Condensation behaviors on the surface were observed at the micro-scale using an Environmental scanning electron microscope (ESEM). Apparently-spherical droplets formed at very low heat flux q' ∼20 kW/m{sup 2} but hemispherical droplets formed at high q' ∼ 440 kW/m{sup 2} . At high q', heat transfer coefficients were lower on the superhydrophobic surface than on a hydrophobic surface although the superhydrophobic surface is water repellent so droplets roll off. The results of contact angle hysteresis and ESEM image revealed that the reduced heat transfer of the surface can be attributed to the large size of departing droplets caused by adhesive condensed droplets at nucleation sites. The results suggest that the effect of q' or degree of sub-cooling of a condensation wall determine the droplet shape, which is closely related to removal rates of condensates and finally to the heat transfer coefficient.

  1. Heat Roadmap Europe 2

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg

    Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible. In these strate......Many strategies have already been proposed for the decarbonisation of the EU energy system by the year 2050. These typically focus on the expansion of renewable energy in the electricity sector and subsequently, electrifying both the heat and transport sectors as much as possible....... In these strategies, the role of district heating has never been fully explored system, nor have the benefits of district heating been quantified at the EU level. This study combines the mapping of local heat demands and local heat supplies across the EU27. Using this local knowledge, new district heating potentials...... are identified and then, the EU27 energy system is modelled to investigate the impact of district heating. The results indicate that a combination of heat savings, district heating in urban areas, and individual heat pumps in rural areas will enable the EU27 to reach its greenhouse gas emission targets by 2050...

  2. A literature survey on numerical heat transfer

    Science.gov (United States)

    Shih, T. M.

    1982-12-01

    Technical papers in the area of numerical heat transfer published from 1977 through 1981 are reviewed. The journals surveyed include: (1) ASME Journal of Heat Transfer, (2) International Journal of Heat and Mass Transfer, (3) AIAA Journal, (4) Numerical Heat Transfer, (5) Computers and Fluids, (6) International Journal for Numerical Methods in Engineering, (7) SIAM Journal of Numerical Analysis, and (8) Journal of Computational Physics. This survey excludes experimental work in heat transfer and numerical schemes that are not applied to equations governing heat transfer phenomena. The research work is categorized into the following areas: (A) conduction, (B) boundary-layer flows, (C) momentum and heat transfer in cavities, (D) turbulent flows, (E) convection around cylinders and spheres or within annuli, (F) numerical convective instability, (G) radiation, (H) combustion, (I) plumes, jets, and wakes, (J) heat transfer in porous media, (K) boiling, condensation, and two-phase flows, (L) developing and fully developed channel flows, (M) combined heat and mass transfer, (N) applications, (O) comparison and properties of numerical schemes, and (P) body-fitted coordinates and nonuniform grids.

  3. Energy Management of Combined Cooling, Heating and Power Micro Energy Grid Based on Leader-Follower Game Theory

    Directory of Open Access Journals (Sweden)

    Kaijun Lin

    2018-03-01

    Full Text Available In this paper, we consider a general model and solution algorithm for the energy management of combined cooling, heating, and power micro energy grid (MEG under the game theory framework. An innovative dynamic leader-follower game strategy is proposed in this paper to balance the interactions between MEG and user. We show that such game between MEG and user has a unique Nash equilibrium (NE, and in order to quantify the user’s expenditure and dissatisfaction, we model them and adopt the fuzzy bi-objective algorithm. For more details in the proposed game model, the MEG leads the game by deciding energy sales prices and optimizing the power, cooling and heating outputs according to the user’s load plan to maximize its own profit. With the prices being released by MEG, user’s adjustment of energy consumption follows and is again fed to MEG. In practice, we initialize simulations with daily loads of a typical community. As the numerical results demonstrate, MEG is proficient in consumption capacity of renewable energy and energy optimization. It also shows that the user achieves his economic optimum with experience of energy usage taken into account.

  4. Design for micro-combined cooling, heating and power systems stirling engines and renewable power systems

    CERN Document Server

    2015-01-01

    ‘Design for Micro-Combined Cooling, Heating & Power Systems’ provides a manual for the technical and structural design of systems for supplying decentralised energy in residential buildings. It presents the micro-combined cooling, heating & power systems Stirling engines & renewable energy sources (mCCHP-SE-RES) systems in an accessible manner both for the public at large, and for professionals who conceive, design or commercialise such systems or their components.  The high performance levels of these systems are demonstrated within the final chapter by the results of an experiment in which a house is equipped with a mCCHP-SE-RES system. The reader is also familiarized with the conceptual, technical and legal aspects of modern domestic energy systems; the components that constitute these systems; and advanced algorithms for achieving the structural and technical design of such systems. In residential buildings, satisfying demands of durable development has gradually evolved from necessity to...

  5. Combining the pressure effect with local heat treatment for improving the sheet metal forming process

    Science.gov (United States)

    Palumbo, G.; Piccininni, A.; Guglielmi, P.; Sorgente, D.; Tricarico, L.

    2016-08-01

    The present work deals with the advantages in the Hydromechanical Deep Drawing (HDD) when AA5754 Tailored Heat Treated Blanks (THTBs) are adopted. It is well known that the creation of a suitable distribution of material properties increases the process performance. When non heat-treatable alloys are considered, the THTB approach can be successfully applied to increase the Limit Drawing Ratio (LDR) by changing the peripheral zone into the annealed state starting from a cold-worked blank. If this approach is combined with the advantages of a counterpressure, even more remarkable improvements can be achieved. Due to the large number of involved parameters, the optimized design of both the local treatment and the pressure profile were investigated coupling an axial symmetric Finite Element model with the integration platform modeFRONTIER. Results confirmed the possibility of increasing the LDR from 2.0 (Deep Drawing using a blank in the annealed