WorldWideScience

Sample records for absorption heat

  1. Absorption heat pump system

    Science.gov (United States)

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  2. Absorption heat pump system

    Science.gov (United States)

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  3. Absorption-heat-pump system

    Science.gov (United States)

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  4. Carbon Dioxide Absorption Heat Pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  5. Atmospheric Solar Heating in Minor Absorption Bands

    Science.gov (United States)

    Chou, Ming-Dah

    1998-01-01

    Solar radiation is the primary source of energy driving atmospheric and oceanic circulations. Concerned with the huge computing time required for computing radiative transfer in weather and climate models, solar heating in minor absorption bands has often been neglected. The individual contributions of these minor bands to the atmospheric heating is small, but collectively they are not negligible. The solar heating in minor bands includes the absorption due to water vapor in the photosynthetically active radiation (PAR) spectral region from 14284/cm to 25000/cm, the ozone absorption and Rayleigh scattering in the near infrared, as well as the O2 and CO2 absorption in a number of weak bands. Detailed high spectral- and angular-resolution calculations show that the total effect of these minor absorption is to enhance the atmospheric solar heating by approximately 10%. Depending upon the strength of the absorption and the overlapping among gaseous absorption, different approaches are applied to parameterize these minor absorption. The parameterizations are accurate and require little extra time for computing radiative fluxes. They have been efficiently implemented in the various atmospheric models at NASA/Goddard Space Flight Center, including cloud ensemble, mesoscale, and climate models.

  6. Absorption heat pump cycles with NH

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.

    2017-01-01

    Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing water or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption refrigeration or heat pump cycles. In this paper, performances of 9

  7. Absorption heat pump for space applications

    Science.gov (United States)

    Nguyen, Tuan; Simon, William E.; Warrier, Gopinath R.; Woramontri, Woranun

    1993-01-01

    In the first part, the performance of the Absorption Heat Pump (AHP) with water-sulfuric acid and water-magnesium chloride as two new refrigerant-absorbent fluid pairs was investigated. A model was proposed for the analysis of the new working pairs in a heat pump system, subject to different temperature lifts. Computer codes were developed to calculate the Coefficient of Performance (COP) of the system with the thermodynamic properties of the working fluids obtained from the literature. The study shows the potential of water-sulfuric acid as a satisfactory replacement for water-lithium bromide in the targeted temperature range. The performance of the AHP using water-magnesium chloride as refrigerant-absorbent pair does not compare well with those obtained using water-lithium bromide. The second part concentrated on the design and testing of a simple ElectroHydrodynamic (EHD) Pump. A theoretical design model based on continuum electromechanics was analyzed to predict the performance characteristics of the EHD pump to circulate the fluid in the absorption heat pump. A numerical method of solving the governing equations was established to predict the velocity profile, pressure - flow rate relationship and efficiency of the pump. The predicted operational characteristics of the EHD pump is comparable to that of turbomachinery hardware; however, the overall efficiency of the electromagnetic pump is much lower. An experimental investigation to verify the numerical results was conducted. The pressure - flow rate performance characteristics and overall efficiency of the pump obtained experimentally agree well with the theoretical model.

  8. Absorption heat pump for space applications

    Science.gov (United States)

    Nguyen, Tuan; Simon, William E.; Warrier, Gopinath R.; Woramontri, Woranun

    1993-12-01

    In the first part, the performance of the Absorption Heat Pump (AHP) with water-sulfuric acid and water-magnesium chloride as two new refrigerant-absorbent fluid pairs was investigated. A model was proposed for the analysis of the new working pairs in a heat pump system, subject to different temperature lifts. Computer codes were developed to calculate the Coefficient of Performance (COP) of the system with the thermodynamic properties of the working fluids obtained from the literature. The study shows the potential of water-sulfuric acid as a satisfactory replacement for water-lithium bromide in the targeted temperature range. The performance of the AHP using water-magnesium chloride as refrigerant-absorbent pair does not compare well with those obtained using water-lithium bromide. The second part concentrated on the design and testing of a simple ElectroHydrodynamic (EHD) Pump. A theoretical design model based on continuum electromechanics was analyzed to predict the performance characteristics of the EHD pump to circulate the fluid in the absorption heat pump. A numerical method of solving the governing equations was established to predict the velocity profile, pressure - flow rate relationship and efficiency of the pump. The predicted operational characteristics of the EHD pump is comparable to that of turbomachinery hardware; however, the overall efficiency of the electromagnetic pump is much lower. An experimental investigation to verify the numerical results was conducted. The pressure - flow rate performance characteristics and overall efficiency of the pump obtained experimentally agree well with the theoretical model.

  9. Absorption heat transformers and an industrial application

    Energy Technology Data Exchange (ETDEWEB)

    Horuz, Ilhami; Kurt, Bener [University of Uludag, Faculty of Engineering and Architecture, Department of Mechanical Engineering, 16059 Gorukle, Bursa (Turkey)

    2010-10-15

    Absorption Heat Transformer (AHT) systems are devices with the unique capability of raising the temperature of low or moderately warm waste heat sources to more useful levels. The study includes an investigation to analyze the AHT systems using water-lithium bromide solutions with water as the refrigerant. First, a basic AHT system was described, the operating sequence was explained and thermodynamic system analysis was presented. Next, an application of the AHT system to an industrial company was analyzed. A computer code was prepared to determine the effect of different parameters on the AHT system performance and the results were presented in graphical form. Additionally, it was shown that how the basic AHT system could be modified to increase the COP and the heat transfer at the absorber, in other words, the hot process water produced. The system performance data were presented in a tabular form for different system modifications from the base system for comparison. It was proven that, by applying different modifications, the COP could be increased by 14.1%, the heat transfer at the absorber by 158.5% and the hot process water produced by 3.59% compared to the basic AHT system. (author)

  10. Absorption heat pumps in heating and cooling systems. Absorptiolaempoepumppu rakennusten laemmitys- ja jaeaehdytysjaerjestelmaessae

    Energy Technology Data Exchange (ETDEWEB)

    Aittomaeki, A.; Vaelimaeki, A.; Koepsi, M.

    1989-01-01

    The application of an absorption heat pumps as the heating and cooling system of an office building has been studied by means of a simulation model, designed for this application purpose. The effects of an absorption heat pump on emissions that are harmful to the environment depend on the fuel used. If the fuel is lightweight oil or gas, the sulphur and particle emissions diminish, but NO[sub x] and hydrocarbon emissions may increase as the combustion units become smaller. The use of an absorption heat pump reduces CFC emissions because other refrigerants are used in an absorption heat pump.

  11. Absorption heat pumps in heating and cooling systems; Absorptiolaempoepumppu rakennusten laemmitys- ja jaeaehdytysjaerjestelmaessae

    Energy Technology Data Exchange (ETDEWEB)

    Aittomaeki, A.; Vaelimaeki, A.; Koepsi, M.

    1989-12-31

    The application of an absorption heat pumps as the heating and cooling system of an office building has been studied by means of a simulation model, designed for this application purpose. The effects of an absorption heat pump on emissions that are harmful to the environment depend on the fuel used. If the fuel is lightweight oil or gas, the sulphur and particle emissions diminish, but NO{sub x} and hydrocarbon emissions may increase as the combustion units become smaller. The use of an absorption heat pump reduces CFC emissions because other refrigerants are used in an absorption heat pump.

  12. High-Absorptance Radiative Heat Sink

    Science.gov (United States)

    Cafferty, T.

    1983-01-01

    Absorptance of black-painted open-cell aluminum honeycomb improved by cutting honeycomb at angle or bias rather than straight across. This ensures honeycomb cavities escapes. At each reflection radiation attenuated by absorption. Applications include space-background simulators, space radiators, solar absorbers, and passive coolers for terrestrial use.

  13. Analysis of Decentralized Control for Absorption Cycle Heat Pumps

    DEFF Research Database (Denmark)

    Vinther, Kasper; Just Nielsen, Rene; Nielsen, Kirsten Mølgaard

    2015-01-01

    Email Print Request Permissions This paper investigates decentralized control structures for absorption cycle heat pumps and a dynamic nonlinear model of a single-effect LiBr-water absorption system is used as case study. The model has four controllable inputs, which can be used to stabilize...

  14. Coupled dual loop absorption heat pump

    Science.gov (United States)

    Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.

    1985-01-01

    A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

  15. High temperature absorption compression heat pump for industrial waste heat

    DEFF Research Database (Denmark)

    Reinholdt, Lars; Horntvedt, B.; Nordtvedt, S. R.

    2016-01-01

    , and they have proved themselves a very efficient and reliable technology for applications that have large temperature changes on the heat sink and/or heat source. The concept of Carnot and Lorenz efficiency and its use in the analysis of system integration is shown. A 1.25 MW system having a Carnot efficiency...

  16. Absorption Cycle Heat Pump Model for Control Design

    DEFF Research Database (Denmark)

    Vinther, Kasper; Just Nielsen, Rene; Nielsen, Kirsten Mølgaard

    2015-01-01

    Heat pumps have recently received increasing interest due to green energy initiatives and increasing energy prices. In this paper, a nonlinear dynamic model of a single-effect LiBr-water absorption cycle heat pump is derived for simulation and control design purposes. The model is based...... on an actual heat pump located at a larger district heating plant. The model is implemented in Modelica and is based on energy and mass balances, together with thermodynamic property functions for LiBr and water and staggered grid representations for heat exchangers. Model parameters have been fitted...... to operational data and different scenarios are simulated to investigate the operational stability of the heat pump. Finally, this paper provides suggestions and examples of derivation of lower order linear models for control design. © Copyright IEEE - All rights reserved....

  17. Development of an Ionic-Liquid Absorption Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Don

    2011-03-29

    Solar Fueled Products (SFP) is developing an innovative ionic-liquid absorption heat pump (ILAHP). The development of an ILAHP is extremely significant, as it could result in annual savings of more than 190 billion kW h of electrical energy and $19 billion. This absorption cooler uses about 75 percent less electricity than conventional cooling and heating units. The ILAHP also has significant environmental sustainability benefits, due to reduced CO2 emissions. Phase I established the feasibility and showed the economic viability of an ILAHP with these key accomplishments: • Used the breakthrough capabilities provided by ionic liquids which overcome the key difficulties of the common absorption coolers. • Showed that the theoretical thermodynamic performance of an ILAHP is similar to existing absorption-cooling systems. • Established that the half-effect absorption cycle reduces the peak generator temperature, improving collector efficiency and reducing collector area. • Component testing demonstrated that the most critical components, absorber and generator, operate well with conventional heat exchangers. • Showed the economic viability of an ILAHP. The significant energy savings, sustainability benefits, and economic viability are compelling reasons to continue the ILAHP development.

  18. Study of coupled heat and mass transfer during absorption of ...

    Indian Academy of Sciences (India)

    Performance studies on MmNi4·6Al0·4 based hydrogen storage device are carried out by varying the hydrogen supply pressure, absorption (cooling fluid) temperature, overall heat transfer coefficient and hydride bed thickness. Effect of convection terms in the energy equation on hydrogen storage performance is found to ...

  19. Study of coupled heat and mass transfer during absorption of ...

    Indian Academy of Sciences (India)

    Abstract. A two-dimensional numerical analysis of coupled heat and mass trans- fer processes in a cylindrical metal hydride reactor containing MmNi4·6Al0·4 is presented. To understand the hydrogen absorption mechanism the governing equa- tions for energy, momentum and mass conservation and reaction kinetic ...

  20. Absorption chillers integration in a combined heat and power plant

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J. C.; Fernandez, F.; Castells, F. [Barcelona Univ., Tarragona (Spain). Dept. d`Enginyeria Quimica i Bioqumica

    1996-11-01

    Inclusion of an absorption cycle within a combined heat and power plant (CHP) was evaluated. To determine the most suitable configuration of the energy network generation system and absorption chiller, a simulation and optimization model was constructed. To validate the optimization model, a case study using actual data from existing operating plants has been used. In the case described the cooling facilities from the absorption cycle were used to lower the inlet temperature to the compressor of the gas turbine to improve the overall plant efficiency. Waste steam from the steam network was used in the generator of the absorption chiller. A reduction in steam wastes, and an improvement in overall plant efficiency was observed. A simulation model of a single effect absorption chiller, using water-lithium bromide as the working fluid pair, was used to validate the methodology. Results showed that the benefits of integrating the absorption refrigeration cycle (ARC) depends directly on the refrigeration demand, and on the benefit produced by the waste steam recovered. The increase in power generation, allowing a reduction in primary energy consumption, showed a slight economic advantage over the conventional compression cycle. 13 refs., 7. tabs., 6 figs.

  1. Heat Transfer Performance for Evaporator of Absorption Refrigerating Machine

    Science.gov (United States)

    Kunugi, Yoshifumi; Usui, Sanpei; Ouchi, Tomihisa; Fukuda, Tamio

    An experiment was conducted to check the heat transfer performance of evaporators with grooved tubes for absorption refrigerating machines. Heat transfer rate of evaporators were 35kW and 70kW. The range of the flow rate of the sprayed refrigerant per unit length Γ was 1 to 50kg/hm, and the outside diameters of the tubes, D0 were 16 and 19.6 mm. About 80 to 100 % increase of heat transfer rate over a plane surfaced tube is obtained by using grooved tube. The heat transfer coefficients for evaporation are correlated by the equation αE0=(Γ/D0)1/2. The substantial surface area, which is about three times larger than that of plane surfaced tube, is used in the above correlation.

  2. Waste Heat Powered Ammonia Absorption Refrigeration Unit for LPG Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Donald C, Energy Concepts Co.; Lauber, Eric, Western Refining Co.

    2008-06-20

    An emerging DOE-sponsored technology has been deployed. The technology recovers light ends from a catalytic reformer plant using waste heat powered ammonia absorption refrigeration. It is deployed at the 17,000 bpd Bloomfield, New Mexico refinery of Western Refining Company. The technology recovers approximately 50,000 barrels per year of liquefied petroleum gas that was formerly being flared. The elimination of the flare also reduces CO2 emissions by 17,000 tons per year, plus tons per year reductions in NOx, CO, and VOCs. The waste heat is supplied directly to the absorption unit from the Unifiner effluent. The added cooling of that stream relieves a bottleneck formerly present due to restricted availability of cooling water. The 350oF Unifiner effluent is cooled to 260oF. The catalytic reformer vent gas is directly chilled to minus 25oF, and the FCC column overhead reflux is chilled by 25oF glycol. Notwithstanding a substantial cost overrun and schedule slippage, this project can now be considered a success: it is both profitable and highly beneficial to the environment. The capabilities of directly-integrated waste-heat powered ammonia absorption refrigeration and their benefits to the refining industry have been demonstrated.

  3. Heat and mass transfer through spiral tubes in absorber of absorption heat pump system for waste heat recovery

    Directory of Open Access Journals (Sweden)

    Yoshinori Itaya

    2017-06-01

    Full Text Available Heat and mass transfer of a LiBr/water absorption heat pump system (AHP was experimentally studied during working a heating-up mode. The examination was performed for a single spiral tube, which was simulated for heat transfer tubes in an absorber. The inside and outside of the tube were subjected to a film flow of the absorption liquid and exposed to the atmosphere, respectively. The maximum temperature of the absorption liquid was observed not at the entrance but in the region a little downward from the entrance in the tube. The steam absorption rate and/or heat generation rate in the liquid film are not constant along the tube. Hence the average convective heat transfer coefficient between the liquid film flowing down and the inside wall of the tube was determined based on a logarithmic mean temperature difference between the tube surface temperature and the film temperature at the maximum temperature location and the bottom. The film heat and mass transfer coefficients rose with increasing Reynolds number of the liquid film stream. The coefficients showed opposite trend to the empirical correlation reported for laminar film flow on a straight smooth tube in a refrigeration mode in the past work. The fact can be caused due to a turbulent promotion effect of the liquid in a spiral tube.

  4. Wind power integration in Aalborg Municipality using compression heat pumps and geothermal absorption heat pumps

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2013-01-01

    -temperature geothermal resources. The analyses have also demonstrated that the municipality will still rely heavily on surrounding areas for electric load balancing assistance. With a departure in a previously elaborated 100% renewable energy scenario, this article investigates how absorption heat pumps (AHP...

  5. Performance of Different Experimental Absorber Designs in Absorption Heat Pump Cycle Technologies: A Review

    Directory of Open Access Journals (Sweden)

    Jonathan Ibarra-Bahena

    2014-02-01

    Full Text Available The absorber is a major component of absorption cycle systems, and its performance directly impacts the overall size and energy supplies of these devices. Absorption cooling and heating cycles have different absorber design requirements: in absorption cooling systems, the absorber works close to ambient temperature, therefore, the mass transfer is the most important phenomenon in order to reduce the generator size; on the other hand, in heat transformer absorption systems, is important to recover the heat delivered by exothermic reactions produced in the absorber. In this paper a review of the main experimental results of different absorber designs reported in absorption heat pump cycles is presented.

  6. Exergoeconomic Performance Comparison and Optimization of Single-Stage Absorption Heat Transformers

    National Research Council Canada - National Science Library

    S Mohammad S Mahmoudi; Sina Salehi; Mortaza Yari; Marc A Rosen

    2017-01-01

    Three single-stage absorption heat transformer (SSHT) configurations are modeled, analyzed and compared from the viewpoints of thermodynamics and economics, using the Engineering Equation Solver (EES) software...

  7. Heat of Absorption of CO2 in Aqueous Solutions of DEEA, MAPA and their Mixture

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; von Solms, Nicolas; Thomsen, Kaj

    2013-01-01

    A reaction calorimeter was used to measure the differential heat of absorption of CO2 in phase change solvents as a function of temperature, CO2 loading and solvent composition. The measurements were taken for aqueous solutions of 2-(diethylamino)ethanol (DEEA), 3-(methylamino)propylamine (MAPA...... and 120°C at a CO2 feed pressure of 600kPa. In single aqueous amine solutions, heat of absorption increases with increase in temperature and depends on thetype of amine used. DEEA, a tertiary amine, has lower heat of absorption compared to MAPA being a diamine with primary and secondary amine functional...... groups. For amine mixtures, heat of absorption is a function of CO2 loading and temperature. The heat of absorption against CO2 loading depends on the composition of the amines in the mixture. All the measured data in this work were compared with 30% MEA at absorption (40°C) and desorption (120°C...

  8. Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-09-01

    BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

  9. Screening Criteria for ILs used in NH3 Based Absorption Heat Pump Systems

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.; Groll, Eckhard

    2016-01-01

    This paper describes a properties-optimization work for the working fluids in NH3 / ionic liquid (ILs) based single-effect absorption heat pumps. The optimum parameters of the IL can be used as criteria in screening task-specified ILs, which play the role of absorbents, in absorption heat pumps.

  10. Commercial Absorption Heat Pump Water Heater: Beta Prototype Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ally, Moonis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Vishaldeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-10-14

    The Beta version of the Commercial Absorption Heat Pump (CAHP) water heater was evaluated in the environmental chambers at Oak Ridge National Laboratory. Ambient air conditions ranged from 17 to 75 oF and inlet water temperatures ranged from 100 to 120oF in order to capture trends in performance. The unit was operated under full fire (100%) and partial fire (55%). The unit was found to perform at 90% of the project goal at the design conditions of 47oF ambient and 100oF water temperatures. The trends across the full range of environmental conditions were as expected for ambient air temperatures above 32oF. Below this temperature and for the full fire condition, frost accumulated on the evaporator coil. In future work a defrost strategy will be enabled, the unit will be thoroughly cleaned of an oil contamination and the rectifier will be reconfigured in order to meet the design goals and have a field test unit ready in early 2017.

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

    Directory of Open Access Journals (Sweden)

    Luzhkovoy Dmitriy S.

    2017-01-01

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

  12. INVESTIGATION OF SOLAR ABSORPTANCE OF BUILDING EXTERNAL SURFACES FROM HEAT FLUX POINT OF VIEW

    Directory of Open Access Journals (Sweden)

    Meral ÖZEL

    2006-02-01

    Full Text Available In this study, solar absorptance of external surfaces of buildings has been numerically investigated from the heat gain and losses point of view. For this purpose, external surface solar absorptance was icreased from 0 to 1with an ratio of 0.1 and, for the summer and winter conditions, heat fluxs was calculated by considering orientations of the wall and its roof for brick and concrete structure materials. Besides, external surface absorptance was assumed as 0.2, 0.5 and 0.9, respectively. Than, heat gain and losses were calculated to insulation thickness increasing on the outdoor surface of wall. Results obtained were presented as graphics

  13. A Stable Carbon Nanotube Nanofluid for Latent Heat-Driven Volumetric Absorption Solar Heating Applications

    Directory of Open Access Journals (Sweden)

    Nathan Hordy

    2015-01-01

    Full Text Available Recently, direct solar collection through the use of broadly absorbing nanoparticle suspensions (known as nanofluids has been shown as a promising method to improve efficiencies in solar thermal devices. By utilizing a volatile base fluid, this concept could also be applied to the development of a direct absorption heat pipe for an evacuated tube solar collector. However, for this to happen or for any other light-induced vapor production applications, the nanofluid must remain stable over extended periods of time at high temperatures and throughout repetitive evaporation/condensation cycles. In this work, we report for the first time a nanofluid consisting of plasma-functionalized multiwalled carbon nanotubes (MWCNTs suspended in denatured alcohol, which achieves this required stability. In addition, optical characterization of the nanofluid demonstrates that close to 100% of solar irradiation can be absorbed over a relatively small nanofluid thickness.

  14. Slip Effect on MHD Chemically Reacting Convictive Boundary Layer Flow with Heat Absorption

    National Research Council Canada - National Science Library

    Ayano, Mekonnen Shifferaw; Demeke, Negussie Tadege

    2016-01-01

      The aim of this paper is to investigate steady magneto micropolar fluid past a stretched semi-infinite vertical and permeable surface taking into account heat absorption, hall and ion-slip effect...

  15. Numerical modelling of combined heat and mass transfer in film absorption

    Directory of Open Access Journals (Sweden)

    Bartashevich Maria V.

    2017-01-01

    Full Text Available Heat and mass transfer during absorption on a film of lithium bromide water solution flowing by a cooled wall in the steam atmosphere is numerically investigated in this paper. The self-similar solutions are using as the initial conditions for solving the problem beyond the entrance region. The key criteria characterizing heat and mass transfer in the film absorption with uniform velocity profile and with a constant thickness have been determined.

  16. Heating of solar coronal loops by resonant absorption of Alfven waves

    Science.gov (United States)

    Grossmann, William; Smith, Robert A.

    1988-01-01

    Numerical calculations governing the efficiency of coronal loop heating by the resonant absorption of shear Alfven waves are reported. The loop structure is modeled by a class of axisymmetric force-free equilibria of a long straight cylinder, approximating a large aspect ratio loop. For a range of parameters characterizing the evolution of solar coronal loops, the absorption bandwidth falls in the frequency range of the photospheric motions due to granulation and p-modes. Resonant Alfven wave absorption is thus a viable mechanism for coronal loop heating.

  17. On the development of high temperature ammonia-water hybrid absorption-compression heat pumps

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

    2015-01-01

    Ammonia-water hybrid absorption-compression heat pumps (HACHP) are a promising technology for development of ecient high temperature industrial heat pumps. Using 28 bar components HACHPs up to 100 °C are commercially available. Components developed for 50 bar and 140 bar show that these pressure...

  18. Nonresonant absorption of shear Alfven waves. [in solar coronal heating and solar wind acceleration

    Science.gov (United States)

    Strauss, H. R.

    1991-01-01

    Resonant absorption of shear Alfven waves is thought to be a likely candidate to explain heating of the solar corona and acceleration of the solar wind. A difficulty with the theory is that the absorption process is slow. Moreover, heating occurs in a very thin layer. A faster absorption mechanism is nonresonant absorption by compressional viscosity, in a curved magnetic field. Heating is nonresonant and is not localized to a narrow layer. The effect could be quite important where the solar coronal magnetic field is strongly curved, in the chromosphere. It could also be important on open field lines in the upper corona, where the compressional viscosity is large. It might imply that a significant part of outgoing Alfven waves are absorbed in the corona.

  19. Solar heating and cooling system with absorption chiller and low temperature latent heat storage: Energetic performance and operational experience

    Energy Technology Data Exchange (ETDEWEB)

    Helm, M.; Keil, C.; Hiebler, S.; Mehling, H.; Schweigler, C. [Bavarian Center for Applied Energy Research (ZAE Bayern) (Germany)

    2009-06-15

    Absorption cooling systems based on water/lithium bromide (LiBr) solution typically require an open wet cooling tower to transfer the reject heat to the ambient. Yet, water consumption, the need for water make-up and cleaning, formation of fog, and the risk of Legionella bacteria growth are hindering factors for the implementation of small solar cooling systems. The application of a latent heat storage supporting the heat rejection of the absorption chiller in conjunction with a dry cooling system allows eliminating the wet cooling tower. By that means heat rejection of the chiller is shifted to periods with lower ambient temperatures, i.e. night time or off-peak hours. The system concept and the hydraulic scheme together with an analysis of the energetic performance of the system are presented, followed by a report on the operation of a first pilot installation. (author)

  20. European Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Vishaldeep [ORNL; Shen, Bo [ORNL; Keinath, Chris [Stone Mountain Technologies, Inc., Johnson City; Garrabrant, Michael A. [Stone Mountain Technologies, Inc., Johnson City; Geoghegan, Patrick J [ORNL

    2017-01-01

    High efficiency gas-burning hot water heating takes advantage of a condensing heat exchanger to deliver improved combustion efficiency over a standard non-condensing configuration. The water heating is always lower than the gas heating value. In contrast, Gas Absorption Heat Pump (GAHP) hot water heating combines the efficiency of gas burning with the performance increase from a heat pump to offer significant gas energy savings. An ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. In comparison with air source electric heat pumps, the absorption system can maintain higher coefficients of performance in colder climates. In this work, a GAHP commercial water heating system was compared to a condensing gas storage system for a range of locations and climate zones across Europe. The thermodynamic performance map of a single effect ammonia-water absorption system was used in a building energy modeling software that could also incorporate the changing ambient air temperature and water mains temperature for a specific location, as well as a full-service restaurant water draw pattern.

  1. Ab-sorption machines for heating and cooling in future energy systems - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tozer, R.; Gustafsson, M.

    2000-12-15

    After the Executive Summary and a brief introductory chapter, Chapter 2, Sorption Technologies for Heating and Cooling in Future Energy Systems, reviews the main types of sorption systems. Chapter 3, Market Segmentation, then considers the major segments of the market including residential, commercial/institutional and industrial, and the types of sorption hardware most suitable to each. The highly important residential and commercial/institutional markets are mostly concerned with air-conditioning of buildings. More applications are identified and discussed for the industrial market, including refrigeration, food-storage cooling, process cooling, and process heating at various temperature ranges from hot water for hand-washing to high-temperature (greater than 130C). Other interesting industrial applications are absorption cooling or heating combined with co-generation, desiccant cooling, gas turbine inlet air cooling, combining absorption chillers with district heating systems, direct-fired absorption heat pumps (AHPs), and a closed greenhouse concept being developed for that economically important sector in the Netherlands. Most of the sorption market at this time comprises direct-fired absorption chillers, or hot water or steam absorption chillers indirectly driven by direct-fired boilers. Throughout the report, this category of absorption chillers is referred to generically as 'direct-fired'. In addition, this report covers absorption (reversible) heat pumps, absorption heat transformers, compression-absorption heat pumps, and adsorption chillers and heat pumps. Adsorption systems together with desiccant systems are also addressed. Chapter 4, Factors Affecting the Market, considers economic, environmental and policy issues. The geographical make-up of the world sorption market is then reviewed, followed by a number of practical operating and control considerations. These include vacuum requirements, crystallisation, corrosion, maintenance, health and

  2. Multifunctional absorption technology in district heating systems; Absorptionsteknik med multifunktion i fjaerrvaermesystem

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Viktoria; Setterwall, Fredrik

    2010-05-15

    Within the framework of the IEA's implementing agreement on heat pumping technologies, a state-of-the-art assessment of absorption technology was presented the year 2000. There, barriers for increased implementation of absorption technology were pointed out as being the high investment cost, as well as lack of knowledge with engineers and other actors. The project presented herein has analyzed the situation ten years later, with a wide scope of using the absorption technology - from ice to steam production in a district energy system. The overall aim of the presented project is to provide new knowledge on the technical and economical possibilities of integrating multiple function absorption technology in district energy systems. Also, new knowledge on important design parameters for practical and cost-effective design is given, for example the influence of temperatures (heat source as well as heat sink) and desired COP. A combination of renewed state-of-the-art assessment and new calculations has been used to reach this goal. The state-of-the-art assessment show that the increased focus on combined heat and power (CHP) for resource-efficient energy conversion go hand in hand with an increased interest in thermally driven cooling (TDC) technology. This project has identified the following to be specifically district energy adapted in absorption cooling: - design for low return temperature of the heat carrier leaving the generator part - design for 'high enough' COP maintained at part load for heat source temperatures as low as 70 deg C. - cost minimization by optimal sizing of heat exchanger surfaces for district energy design criteria (as opposed to accepting 'off-the-shelf' designs intended for higher operating temperatures). The overall analysis and findings regarding trigeneration concludes that: a. a holistic view of the production of power, heat and cold should be adopted when considering absorption technology in district energy

  3. Heat and Mass Diffusions in the Absorption of Water Vapor by Aqueous Solution of Lithium Bromide

    Science.gov (United States)

    Kashiwagi, Takao; Kurosaki, Yasuo; Nikai, Isao

    The recent development of absorption-type heat pump is highly essential from the viewpoint of extracting the effective energy from waste heat or solar energy. To increase the efficiency of energy conversion, it is important to improve the performance of absorbers. The objective of this paper is to obtain an increased understanding of the fine mechanisms of vapor absorption. A system combining holographic interferometry wity thermometry is adopted to observe the progress of one-dimensional water vapor absorption by aqueous solution of lithium bromide (LiBr) and also to measure the unsteady temperature and concentration distributions in the absorption process. The experiments are carried out under the condition that the solution surface is exposed to the saturated water vapor at reduced pressure, and the effects of LiBr mass concentration on absorption mechanism are examined in the concentration range 20-60 mass%. The interference fringes are analyzed to distinguish between the layers of heat conduction and mass diffusion. The temperature and concentration distributions thus determined experimentally are compared with numerical solutions obtained by the equations for unsteady heat conduction and mass diffusion taking into consideration the effect of heat by dilution, to give reasonable values of mass diffusivity hitherto remaining unknown. Especially in the range of 40-60 mass%, the mass diffusivity decreases extremely with the increase of mass concentration of LiBr and it falls down to 0.7-0.8×10-9 m2/s in case of 60 mass% solution.

  4. Application of customized absorption heat pumps with heating capacities above 500 kW: Project: VIVO, Warngau (near Munich)

    OpenAIRE

    Zachmeier, Peter; Radspieler, Michael; Schweigler, Christian

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] In 2005 a gas fired single effect absorption heat pump was installed at the area of VIVO GmbH, who runs a local civic waste collection point. Besides other recyclable materials, biodegra...

  5. Measurement of XUV-absorption spectra of ZnS radiatively heated foils

    CERN Document Server

    Kontogiannopoulmos, Nikolaos; Thais, Frédéric; Chenais-Popovics, Claude; Sauvan, Pascal; Schott, R; Fölsner, Wolfgang; Arnault, Philippe; Poirier, Michel; Blenski, Thomas

    2008-01-01

    Time-resolved absorption of zinc sulfide (ZnS) and aluminum in the XUV-range has been measured. Thin foils in conditions close to local thermodynamic equilibrium were heated by radiation from laser-irradiated gold spherical cavities. Analysis of the aluminum foil radiative hydrodynamic expansion, based on the detailed atomic calculations of its absorption spectra, showed that the cavity emitted flux that heated the absorption foils corresponds to a radiation temperature in the range 55 60 eV. Comparison of the ZnS absorption spectra with calculations based on a superconfiguration approach identified the presence of species Zn6+ - Zn8+ and S5+ - S6+. Based on the validation of the radiative source simulations, experimental spectra were then compared to calculations performed by post-processing the radiative hydrodynamic simulations of ZnS. Satisfying agreement is found when temperature gradients are accounted for.

  6. Effect of internal heat generation or absorption on MHD free convection from an isothermal truncated cone

    Directory of Open Access Journals (Sweden)

    A.H. Srinivasa

    2016-06-01

    Full Text Available This paper examines the effect of heat generation or absorption on the free convection flow of an incompressible, electrically conducting fluid about an isothermal truncated cone in the presence of a transverse magnetic field. The non-linear coupled partial differential equations governing the flow and heat transfer have been solved numerically, using an efficient implicit finite-difference scheme along with quasilinearization technique. The nonsimilar solutions have been obtained for the problem overcoming numerical difficulties near the leading edge and in the downstream regime, for air (Pr = 0.72. The effects of various physical parameters on skin friction and heat transfer coefficients and, on velocity and temperature are shown graphically for different values of magnetic parameter (M and heat generation/absorption parameter (Q. It is observed that, magnetic field decreases both skin friction and heat transfer coefficients. The effect of heat generation or absorption is found to be very significant on heat transfer, but its effect on skin friction is negligible.

  7. Simultaneous heat and mass transfer in absorption of gases in laminar liquid films

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, G

    1982-09-01

    A theoretical analysis of the combined heat and mass transfer process taking place in the absorption of a gas or vapor into a laminar liquid film is described. This type of process, which occurs in many gas-liquid systems, often releases only a small amount of heat, making the process almost isothermal. In some cases, however, the heat of absorption is significant and temperature variations cannot be ignored. One example, from which the present study originated, is in absorption heat pumps where mass transfer is produced specifically to generate a temperature change. The model analyzed describes a liquid film that flows over an inclined plane and has its free surface in contact with stagnant vapor. The absorption process at the surface creates nonuniform temperature and concentration profiles in the film, which develop until equilibrium between the liquid and vapor is achieved. The energy and diffusion equations are solved simultaneously to give the temperature and concentration variations at the interface and the wall. Two cases of interest are considered: constant-temperature and adiabatic walls. The Nusselt and Sherwood numbers are expressed in terms of the operating parameters, from which heat and mass transfer coefficients can be determined. The Nusselt and Sherwood numbers are found to depend on the Peclet and Lewis numbers as well as on the equilibrium characteristics of the working materials.

  8. Application of waste heat powered absorption refrigeration system to the LNG recovery process

    Energy Technology Data Exchange (ETDEWEB)

    Kalinowski, Paul; Hwang, Yunho; Radermacher, Reinhard [Center for Environmental Energy Engineering, Department of Mechanical Engineering, University of Maryland, College Park, MD 20742 (United States); Al Hashimi, Saleh; Rodgers, Peter [The Petroleum Institute, Abu Dhabi (United Arab Emirates)

    2009-06-15

    The recovery process of the liquefied natural gas requires low temperature cooling, which is typically provided by the vapor compression refrigeration systems. The usage of an absorption refrigeration system powered by waste heat from the electric power generating gas turbine could provide the necessary cooling at reduced overall energy consumption. In this study, a potential replacement of propane chillers with absorption refrigeration systems was theoretically analyzed. From the analysis, it was found that recovering waste heat from a 9 megawatts (MW) electricity generation process could provide 5.2 MW waste heat produced additional cooling to the LNG plant and save 1.9 MW of electricity consumption. Application of the integrated cooling, heating, and power is an excellent energy saving option for the oil and gas industry. (author)

  9. Development of whole energy absorption spectrometer for decay heat measurement on fusion reactor materials

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Fujio; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    To measure decay heat on fusion reactor materials irradiated by D-T neutrons, a Whole Energy Absorption Spectrometer (WEAS) consisting of a pair of large BGO (bismuth-germanate) scintillators was developed. Feasibility of decay heat measurement with WEAS for various materials and for a wide range of half-lives (seconds - years) was demonstrated by experiments at FNS. Features of WEAS, such as high sensitivity, radioactivity identification, and reasonably low experimental uncertainty of {approx} 10 %, were found. (author)

  10. Heat transfer in a stagnation point flow of a second grade fluid over a stretching surface with heat generation/absorption

    Directory of Open Access Journals (Sweden)

    Hazem Ali Attia

    2014-01-01

    Full Text Available The heat transfer in a steady planar stagnation point flow of an incompressible non-Newtonian second grade fluid impinging on a permeable stretching surface with heat generation or absorption is examined. The governing nonlinear momentum and energy equations are solved numerically using finite differences. The influence of the characteristics of the non-Newtonian fluid, the surface stretching velocity, the heat generation/ absorption coefficient, and Prandtl number on both the flow and heat transfer is reported.

  11. The optical absorption of gamma irradiated and heat-treated natural quartz

    Directory of Open Access Journals (Sweden)

    Eduardo Henrique Martins Nunes

    2005-09-01

    Full Text Available Quartz with aluminum as impurity absorbs energy from ionizing radiation and modifies its color. Colorless quartz becomes smoky or dark smoky (morion quartz when exposed to gamma rays. By heat-treatment, smoky quartz may become successively greenish, yellowish, or brownish as the irradiation dose increases. Natural, colorless quartz is routinely colored by irradiation with gamma rays and heat-treatment for jewelry production. The color formation in natural quartz through this procedure is explained based on EPR, UV-VIS, and IR studies of irradiated and irradiated and heat-treated samples. Smoky quartz shows absorption bands in the visible region and a strong EPR signal. After heat-treatment it shows absorption bands in the near UV region with extensions into the visible region and a weak EPR signal. The intensity of the absorption bands is proportional to the irradiation dose. These changes of color are explained by the model of Itoh, Stoneham, and Stoneham. [AlSi O4 /h+]0 centers are produced by irradiation, causing the EPR signal and the absorption bands in the visible region. [AlSi O4]- centers are created from [AlSi O4 /h+]0 centers by heat-treatment. They cannot cause an EPR signal and have absorption bands in the near UV region with extensions into the visible region. The highest concentration of [AlSi O4]- centers occurs when the charge compensators have medium mobility. Lithium should give the best condition for color formation. Sodium (low mobility and hydrogen (high mobility should make smoky quartz colorless after heat-treatment.

  12. Performance analysis of double-effect absorption heat pump cycle using NH

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.

    2017-01-01

    Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing H2O or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption chiller or heat pump cycles. In this paper, NH3/IL working pairs are proposed for implementation in parallel

  13. Performance analysis of double-effect absorption heat pump cycle using NH3/ILs pairs

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.

    2017-01-01

    Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing H2O or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption chiller or heat pump cycles. In this paper, NH3/IL working pairs are proposed for implementation in parallel

  14. Impact of aerosol heat radiation absorption on the dynamics of an atmospheric boundary layer in equilibrium

    NARCIS (Netherlands)

    Barbaro, E.W.; Vilà-Guerau de Arellano, J.; Krol, M.C.; Holtslag, A.A.M.

    2012-01-01

    The objective of this work is to investigate the influence of the shortwave radiation (SW) absorption by aerosols on the dynamics and heat budget of the atmospheric boundary layer (ABL). This study is relevant for areas characterized by large concentrations of light-absorbing aerosol, which are

  15. Molecular Simulation of NH3/Ionic Liquid Mixtures for Absorption Heat Pump Cycles

    NARCIS (Netherlands)

    Kabra, Abhishek; Becker, T.M.; Wang, M.; Infante Ferreira, C.A.; Vlugt, T.J.H.

    2017-01-01

    Force Field based Monte Carlo (MC) simulations are conducted to predict the performance of an absorption heat pump cycle involving NH3/ionic liquid (IL) (refrigerant/absorbent) as working pair. To investigate the thermodynamic performance of the cycle, various properties such as the enthalpy of

  16. Thermodynamic properties of a suitable working fluid mixture for absorption heat pumps

    Science.gov (United States)

    Eichholz, H. D.; Schulz, S.

    1982-04-01

    An absorption heat pump process was considered with reference to thermodynamic properties of methanol lithium bromide as a working fluid. The process was optimized for operating conditions and the binary mixture used. All available thermodynamic data of mixture properties were collected. They were then complemented by vapor-liquid equilibrium measurements and heat of mixing experiments with the result of a theoretical correlation. By a critical selection of properties, the binary mixture CH30H LiBr was qualified as a heat pump working fluid. In addition, thermodynamic properties of methanol are derived by a fundamental equation.

  17. Absorption of intense microwaves and ion acoustic turbulence due to heat transport

    Energy Technology Data Exchange (ETDEWEB)

    De Groot, J.S.; Liu, J.M. [California Univ., Davis, CA (United States); Matte, J.P. [INRS-Energie (Canada)] [and others

    1994-02-04

    Measurements and calculations of the inverse bremsstrahlung absorption of intense microwaves are presented. The isotropic component of the electron distribution becomes flat-topped in agreement with detailed Fokker-Planck calculations. The plasma heating is reduced due to the flat-topped distributions in agreement with calculations. The calculations show that the heat flux at high microwave powers is very large, q{sub max} {approx} 0.3 n{sub e}v{sub e}T{sub e}. A new particle model to, calculate the heat transport inhibition due to ion acoustic turbulence in ICF plasmas is also presented. One-dimensional PIC calculations of ion acoustic turbulence excited due to heat transport are presented. The 2-D PIC code is presently being used to perform calculations of heat flux inhibition due to ion acoustic turbulence.

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

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Ming [Purdue University, West Lafayette, IN; Abdelaziz, Omar [ORNL; Yin, Hongxi [Southeast University, Nanjing, China

    2014-11-01

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

  19. High-efficiency gas heat pump air-conditioner equipped with absorption refrigerator

    Science.gov (United States)

    Kawakami, Ryuichiro; Imai, Kazuya; Nakajima, Hidekazu; Okamoto, Hiroaki; Hihara, Eiji

    To improve rated efficiency and partial load efficiency of gas engine heat pump (GHP), we are developing a new type air-cooled absorption refrigerator which is driven by the engine waste hot water. To shape the compact absorption refrigerator body that was able to be built into the space of a GHP outdoor-unit, an air-cooled sub-cooled adiabatic absorber and flowing liquid film plate type generator were newly developed. Maximum cooling capacity was increased about 20%, rated load COP was increased 40%, and partial load COP was increased 46% or less, as a result of the combination examination of a prototype 8.0kW absorption refrigerator and a 56kW GHP at a laboratory.

  20. Development of energy efficient smart module with variable direction of heat flow, heat capacity and surface absorptivity(I)

    Energy Technology Data Exchange (ETDEWEB)

    Chun, W.K.; Lee, Y.J.; Lee, H.J. [Jeju University, Jeju (Korea, Republic of)] [and others

    1996-02-01

    This work has been carried out to develop thermal diode modules with variable direction of heat flow, heat capacity and surface absorptivity. The module can be used for space heating in winter and reduce the cooling load of buildings in summer. this concept could be also utilized for domestic hot water heating. The modules are categorized as follows; (1) Loop Type Smart Module, (2) Bayonet Type Smart Module, (3) Roller Type Smart Module, (4) Plane Tubeless Solar Collector and Storage System Utilizing the Bayonet Concept. Each system generally features either or both of the passive or active schemes. The Loop Type, in particular, is designed with the photo diode and microprocessor to harness the solar energy more aggressively. It is essential to contrive a totally new design concept apart from conventional ones to fully appreciate the availability of the sun`s energy. In this regard, the solar modules under investigation in the present study is of great significance. (author) 29 refs., 65 figs., 5 photos.

  1. Efficient heat generation in large-area graphene films by electromagnetic wave absorption

    Science.gov (United States)

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

    2017-06-01

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

  2. Heat of Absorption of CO2 in Phase Change Solvents: 2-(Diethylamino)ethanol and 3-(Methylamino)propylamine

    DEFF Research Database (Denmark)

    Waseem Arshad, Muhammad; Fosbøl, Philip Loldrup; von Solms, Nicolas

    2013-01-01

    to these two parameters, it also depends on temperature and the type of amine used. Tertiary alkanolamine (DEEA) has shown greater dependency on these parameters compared to the diamine (MAPA) containing both primary and secondary amine functional groups. In aqueous amine mixtures, heats of absorption depend...... on CO2 loading, temperature, and composition of the constituent amines in the mixture. All measured heat of absorption data were compared with 30 mass % MEA used as a base case....

  3. The Correlation of Coupled Heat and Mass Transfer Experimental Data for Vertical Falling Film Absorption

    Energy Technology Data Exchange (ETDEWEB)

    Keyhani, M; Miller, W A

    1999-11-14

    Absorption chillers are gaining global acceptance as quality comfort cooling systems. These machines are the central chilling plants and the supply for cotnfort cooling for many large commercial buildings. Virtually all absorption chillers use lithium bromide (LiBr) and water as the absorption fluids. Water is the refrigerant. Research has shown LiBr to he one of the best absorption working fluids because it has a high affinity for water, releases water vapor at relatively low temperatures, and has a boiling point much higher than that of water. The heart of the chiller is the absorber, where a process of simultaneous heat and mass transfer occurs as the refrigerant water vapor is absorbed into a falling film of aqueous LiBr. The more water vapor absorbed into the falling film, the larger the chiller's capacity for supporting comfort cooling. Improving the performance of the absorber leads directly to efficiency gains for the chiller. The design of an absorber is very empirical and requires experimental data. Yet design data and correlations are sparse in the open literature. The experimental data available to date have been derived at LiBr concentrations ranging from 0.30 to 0.60 mass fraction. No literature data are readily available for the design operating conditions of 0.62 and 0.64 mass fraction of LiBr and absorber pressures of 0.7 and 1.0 kPa.

  4. Stagnation Point Flow of a Nanofluid toward an Exponentially Stretching Sheet with Nonuniform Heat Generation/Absorption

    Directory of Open Access Journals (Sweden)

    A. Malvandi

    2013-01-01

    Full Text Available This paper deals with the steady two-dimensional stagnation point flow of nanofluid toward an exponentially stretching sheet with nonuniform heat generation/absorption. The employed model for nanofluid includes two-component four-equation nonhomogeneous equilibrium model that incorporates the effects of Brownian diffusion and thermophoresis simultaneously. The basic partial boundary layer equations have been reduced to a two-point boundary value problem via similarity variables and solved analytically via HAM. Effects of governing parameters such as heat generation/absorption λ, stretching parameter ε, thermophoresis , Lewis number Le, Brownian motion , and Prandtl number Pr on heat transfer and concentration rates are investigated. The obtained results indicate that in contrast with heat transfer rate, concentration rate is very sensitive to the abovementioned parameters. Also, in the case of heat generation , despite concentration rate, heat transfer rate decreases. Moreover, increasing in stretching parameter leads to a gentle rise in both heat transfer and concentration rates.

  5. Anvendelse af fjernvarme til køleformål. Absorptionskøleanlæg (Using District Heating Network for Air Conditioning Absorption Refrigeration)

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard

    1996-01-01

    The paper gives a short introduction to absorption refrigeration plants with special attention to the dependency of the heat ratio on the heat source temperature.......The paper gives a short introduction to absorption refrigeration plants with special attention to the dependency of the heat ratio on the heat source temperature....

  6. Dynamic optical absorption characteristics of blood after slow and fast heating.

    Science.gov (United States)

    Jia, Hao; Chen, Bin; Li, Dong

    2017-04-01

    Laser treatment is the most effective therapy in dermatology for vascular skin disorders, such as port-wine stains (PWS). Changes in heat-induced absorbance in blood must be determined for accurate numerical simulation and implementation of multi-pulse laser therapy for treatment of PWS. Thermally induced absorbance changes in hemoglobin in blood were compared in vitro between slow water bath heating and fast heating irradiated by using sub-millisecond Nd:YAG laser. Blood composition at different temperatures was calculated by comparing blood absorption spectra with those of pure HbO2, Hb, and metHb at room temperature. Blood absorbance to heat energy were categorized into three stages distinguished by metHb and coagulation points, which are the validity and security thresholds of the optimized therapy, respectively. Rapid laser heating can distinctively enhance blood absorbance by photochemically induced strong instability compared with slow heating at a constant temperature. Slow heating facilitates metHb point at 70 °C and coagulation point at 75 °C as the temperature of the water bath increases. However, the temperature at which metHb or coagulation point shifts to higher than 10 °C when pulses and fluence in laser irradiation change. Laser fluence less than 20 J/cm(2) and more than 50 J/cm(2) is unsuitable for laser treatment because of its low probability to coagulate vascular hyperplasia and high probability to damage normal tissues adjacent to target lesions, respectively. Few bubbles formed after mediate fluence is beneficial to minimize adverse side-effects. Considering blood absorbance, temperature evolution, and bubble formation, we recommend 30-40 J/cm(2) and 2-4 Hz frequency as the optimal laser parameters in sub-millisecond Nd:YAG laser.

  7. Increasing utilisation of district heating through absorption cooling technology; Oekat fjaerrvaermeutnyttjande med hjaelp av absorptionstekniken

    Energy Technology Data Exchange (ETDEWEB)

    Bjurstroem, Henrik; Ingvarsson, Paul; Zinko, Heimo

    2010-10-15

    The purpose of the research project presented in this report was to find ways to return a lower temperature from the generator of the chillers in a supply/return connection. The initial target is 40 deg C. Ideally, the absorption chiller and possible ulterior uses of the remaining heat in the heat carrier (the water flowing through the generator) should be as close as possible to a pure heat load. The hot-water driven absorption chillers used today to produce cooling in DH networks are exclusively so-called single-effect (Sweden) chillers with water and lithium bromide as working pair. This study aims at raising as much as possible the upper bounds on the absorption chiller capacity that may be connected to a DH network, by lowering the temperature at the outlet. To this end, several approaches have been used: - A search for alternative designs of the absorption chiller, focusing on commercially available and tested technology, both those yielding a large temperature decrease over the generator and those that may be operated at lower temperatures than the conventional solutions; - An examination of the impact of further uses of the remaining heat on temperature in the return line. larger. Smaller units are considered only if they can be used to illustrate a principle. As a complement to this investigation, a few other issues have been treated: - What temperature levels should a system actually be designed for? - The LAVA method to calculate the impact of supply and return temperatures in the DH network on the economics of power production is presented; - Interesting technical solutions using desiccant-aided evaporative cooling are shortly described; - The modern developments in the field of working pairs (refrigerant and absorbent) are reviewed. Assumptions made here are that there is a significant demand for cooling, and that the demand is large enough to justify operating the cogeneration plant at a load level exceeding its lowest acceptable part load rather than

  8. Thermodynamic analysis and optimization of a high temperature triple absorption heat transformer.

    Science.gov (United States)

    Khamooshi, Mehrdad; Parham, Kiyan; Yari, Mortaza; Egelioglu, Fuat; Salati, Hana; Babadi, Saeed

    2014-01-01

    First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver) to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers' efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle.

  9. Modeling MHD Stagnation Point Flow of Thixotropic Fluid with Non-uniform Heat Absorption/Generation

    Science.gov (United States)

    Hayat, Tasawar; Shah, Faisal; Khan, Muhammad Ijaz; Alsaedi, Ahmed; Yasmeen, Tabassum

    2017-11-01

    Here magnetohydrodynamic (MHD) stagnation point flow by nonlinear stretching sheet is discussed. Variable thickness of sheet is accounted. In addition non-uniform heat generation/absorption concept is retained. Numerical treatment to arising nonlinear system is presented. Shooting procedure is adopted for numerical treatment. Graphs and tables lead to physical description of results. It is observed that skin friction enhances for (H a) and it decays for different rising values of (K 1), (K 2) and (n). Further temperature gradient increases for higher estimation of (Pr) and decreases for larger (H a). Major findings of present analysis are presented.

  10. Modeling MHD Stagnation Point Flow of Thixotropic Fluid with Non-uniform Heat Absorption/Generation

    Science.gov (United States)

    Hayat, Tasawar; Shah, Faisal; Khan, Muhammad Ijaz; Alsaedi, Ahmed; Yasmeen, Tabassum

    2017-12-01

    Here magnetohydrodynamic (MHD) stagnation point flow by nonlinear stretching sheet is discussed. Variable thickness of sheet is accounted. In addition non-uniform heat generation/absorption concept is retained. Numerical treatment to arising nonlinear system is presented. Shooting procedure is adopted for numerical treatment. Graphs and tables lead to physical description of results. It is observed that skin friction enhances for ( H a) and it decays for different rising values of ( K 1), ( K 2) and ( n). Further temperature gradient increases for higher estimation of (Pr) and decreases for larger ( H a). Major findings of present analysis are presented.

  11. Effect of thermal radiation on free convection flow and heat transfer over a truncated cone in the presence of pressure work and heat generation/absorption

    Directory of Open Access Journals (Sweden)

    Elbashbeshy E.M.A.

    2016-01-01

    Full Text Available Effect of heat generation or absorption and thermal radiation on free convection flow and heat transfer over a truncated cone in the presence of pressure work is considered. The governing boundary layer equations are reduced to non-similarity boundary layer equations and solved numerically by using Mathematica technique. Comparisons with previously published work on special cases of the problem are performed and the results are found to be in excellent agreement. The solutions are presented in terms of local skin friction, local Nusselt number, velocity and temperature profiles for values of Prandtl number, pressure work parameter, radiation parameter and heat generation or absorption parameter.

  12. Effect of thermal radiation and suction on convective heat transfer of nanofluid along a wedge in the presence of heat generation/absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kasmani, Ruhaila Md; Bhuvaneswari, M. [Centre for Foundation Studies in Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Sivasankaran, S.; Siri, Zailan [Institute of Mathematical Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2015-10-22

    An analysis is presented to find the effects of thermal radiation and heat generation/absorption on convection heat transfer of nanofluid past a wedge in the presence of wall suction. The governing partial differential equations are transformed into a system of ordinary differential equations using similarity transformation. The resulting system is solved numerically using a fourth-order Runge–Kutta method with shooting technique. Numerical computations are carried out for different values of dimensionless parameters to predict the effects of wedge angle, thermophoresis, Brownian motion, heat generation/absorption, thermal radiation and suction. It is found that the temperature increases significantly when the value of the heat generation/absorption parameter increases. But the opposite observation is found for the effect of thermal radiation.

  13. Total Absorption Spectroscopy of Fission Fragments Relevant for Reactor Antineutrino Spectra and Decay Heat Calculations

    Directory of Open Access Journals (Sweden)

    Porta A.

    2016-01-01

    Full Text Available Beta decay of fission products is at the origin of decay heat and antineutrino emission in nuclear reactors. Decay heat represents about 7% of the reactor power during operation and strongly impacts reactor safety. Reactor antineutrino detection is used in several fundamental neutrino physics experiments and it can also be used for reactor monitoring and non-proliferation purposes. 92,93Rb are two fission products of importance in reactor antineutrino spectra and decay heat, but their β-decay properties are not well known. New measurements of 92,93Rb β-decay properties have been performed at the IGISOL facility (Jyväskylä, Finland using Total Absorption Spectroscopy (TAS. TAS is complementary to techniques based on Germanium detectors. It implies the use of a calorimeter to measure the total gamma intensity de-exciting each level in the daughter nucleus providing a direct measurement of the beta feeding. In these proceedings we present preliminary results for 93Rb, our measured beta feedings for 92Rb and we show the impact of these results on reactor antineutrino spectra and decay heat calculations.

  14. Avoiding high return temperatures with absorption coolers in district heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Gebremedhin, A. [Department of Mechanical Engineering, Division of Energy Systems, Linkoeping University, (Sweden); Zinko, H. [Department of Mechanical Engineering, Division of Energy Systems, Linkoeping University (Sweden)

    2004-07-01

    In many countries, much attention is turned to achieve as high temperature difference as possible between supply and return temperature and especially low return temperatures under varying operational conditions. The reason is that some types of production plants can be operated more efficiently with low return temperatures, such as biomass boilers with stack gas coolers, co-generation plants or heat-pumps, to mention some. On the other hand, the big difference between summer and winter load of district heating plants and the increasing demand for chill supply increases also the interest for the use of absorption chillers (ABC) in district heating systems. However, in the normal case of using single effect ABC relatively high return temperatures are delivered to the DH system. In systems with a high amount of ABC load, this can significantly impair the efficiency of the production plants and the overall operational efficiency of the network. In this study, we are investigating the role of two different types of ABC as well as the possibility of matching chiller operation with the existing heat loads in order to achieve suitable low return temperatures. Especially, we also investigate which DH return temperatures will be delivered from DH networks using ABCs in different configurations. (orig.)

  15. Performance of hybrid quad generation system consisting of solid oxide fuel cell system and absorption heat pump

    DEFF Research Database (Denmark)

    Cachorro, Irene Albacete; Daraban, Iulia Maria; Lainé, Guillaume

    2013-01-01

    In this paper a system consisting of an SOFC system for cogeneration of heat and power and vapour absorption heat pump for cooling and freezing is assessed and performance is evaluated. Food industry where demand includes four forms of energy simultaneously is a relevant application such a system...... with natural gas. The natural gas is first converted to a mixture of H2 and CO which feed the anode after a preheating step. The cathode is supplied with preheated air and gives, as output, electrical energy. The anode output is the exhaust gas which represents the thermal energy reservoir for heating...... in order to meet the bought cooling and freezing demands. This is an innovative configuration for absorption heat pumps because the cascade is implemented only in vapour compression heat pumps. A smaller ratio of the exhausted gases supplies the energy demand for space heating. The SOFC is fuelled...

  16. Slip effect on stagnation point flow past a stretching surface with the presence of heat generation/absorption and Newtonian heating

    Science.gov (United States)

    Mohamed, Muhammad Khairul Anuar; Noar, Nor Aida Zuraimi Md; Ismail, Zulkhibri; Kasim, Abdul Rahman Mohd; Sarif, Norhafizah Md; Salleh, Mohd Zuki; Ishak, Anuar

    2017-08-01

    Present study solved numerically the velocity slip effect on stagnation point flow past a stretching surface with the presence of heat generation/absorption and Newtonian heating. The governing equations which in the form of partial differential equations are transformed to ordinary differential equations before being solved numerically using the Runge-Kutta-Fehlberg method in MAPLE. The numerical solution is obtained for the surface temperature, heat transfer coefficient, reduced skin friction coefficient as well as the temperature and velocity profiles. The flow features and the heat transfer characteristic for the pertinent parameter such as Prandtl number, stretching parameter, heat generation/absorption parameter, velocity slip parameter and conjugate parameter are analyzed and discussed.

  17. Crystallization Analysis and Control of Ammonia-Based Air Source Absorption Heat Pump in Cold Regions

    Directory of Open Access Journals (Sweden)

    Wei Wu

    2013-01-01

    Full Text Available Energy consumption of heating and domestic hot water is very high and will keep increasing. Air source absorption heat pump (ASAHP was proposed to overcome the problems of low energy efficiency and high air pollution existing in boiler systems, as well as the problem of bad performance under low ambient temperatures for electrical heat pumps. In order to investigate the crystallization possibility of ammonia-salt ASAHP, crystallization margin (evaluated by solution mass concentration at generating temperature ranging from 100 to 150°C, evaporating temperature from −30 to 10°C, and condensing temperature from 30 to 65°C are analyzed. To prevent the NH3–NaSCN solution from crystallizing, ASAHP integrated with pressure booster located between the evaporator and absorber is simulated. Analysis and comparisons show that NH3–NaSCN is easy to crystallize at relatively high generating temperature, low evaporating temperature, and low condensing temperature. But crystallization margin of NH3–LiNO3 can always stay above 5% for most conditions, keeping away from crystallization. Pressure booster can effectively avoid the crystallization problem that will take place in the NH3–NaSCN ASAHP system.

  18. Thermodynamic optimization of a solar system for cogeneration of water heating/purification and absorption cooling

    Science.gov (United States)

    Hovsapian, Zohrob O.

    This dissertation presents a contribution to understanding the behavior of solar powered air conditioning and refrigeration systems with a view to determining the manner in which refrigeration rate; mass flows, heat transfer areas, and internal architecture are related. A cogeneration system consisting of a solar concentrator, a cavity-type receiver, a gas burner, and a thermal storage reservoir is devised to simultaneously produce water heating/purification and cooling (absorption refrigerator system). A simplified mathematical model, which combines fundamental and empirical correlations, and principles of classical thermodynamics, mass and heat transfer, is developed. An experimental setup was built to adjust and validate the numerical results obtained with the mathematical model. The proposed model is then utilized to simulate numerically the system transient and steady state response under different operating and design conditions. A system global optimization for maximum performance (or minimum exergy destruction) in the search for minimum pull-down and pull-up times, and maximum system second law efficiency is performed with low computational time. Appropriate dimensionless groups are identified and the results presented in normalized charts for general application. The numerical results show that the three way maximized system second law efficiency, etaII,max,max,max, occurs when three system characteristic mass flow rates are optimally selected in general terms as dimensionless heat capacity rates, i.e., (Psisps , Psiwxwx, PsiHs)opt ≅ (1.43, 0.17, 0.19). The minimum pull-down and pull-up times, and maximum second law efficiencies found with respect to the optimized operating parameters are sharp and, therefore important to be considered in actual design. As a result, the model is expected to be a useful tool for simulation, design, and optimization of solar energy systems in the context of distributed power generation.

  19. Thermodynamic Analysis and Optimization of a High Temperature Triple Absorption Heat Transformer

    Directory of Open Access Journals (Sweden)

    Mehrdad Khamooshi

    2014-01-01

    Full Text Available First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers’ efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle.

  20. Thermodynamic Analysis and Optimization of a High Temperature Triple Absorption Heat Transformer

    Science.gov (United States)

    Khamooshi, Mehrdad; Yari, Mortaza; Egelioglu, Fuat; Salati, Hana

    2014-01-01

    First law of thermodynamics has been used to analyze and optimize inclusively the performance of a triple absorption heat transformer operating with LiBr/H2O as the working pair. A thermodynamic model was developed in EES (engineering equation solver) to estimate the performance of the system in terms of the most essential parameters. The assumed parameters are the temperature of the main components, weak and strong solutions, economizers' efficiencies, and bypass ratios. The whole cycle is optimized by EES software from the viewpoint of maximizing the COP via applying the direct search method. The optimization results showed that the COP of 0.2491 is reachable by the proposed cycle. PMID:25136702

  1. Exploiting absorption-induced self-heating in solar cells (Conference Presentation)

    Science.gov (United States)

    Ullbrich, Sascha; Fischer, Axel; Erdenebileg, Enkhtur; Koerner, Christian; Reineke, Sebastian; Leo, Karl; Vandewal, Koen

    2017-04-01

    Absorption of light inevitably leads to a self-heating of each type of solar cell, either due to the excess energy of absorbed photons or non-radiative recombination of charge carriers. Although the effect of temperature on solar cell parameters such as the open-circuit voltage are well known, it is often ignored in Suns-Voc measurements [1]. This measurement technique enables direct access to the diode ideality factor without an influence by series resistance. A frequently seen decrease of the ideality factor or a saturation of the open-circuit voltage at high illumination intensities is often attributed solely to surface recombination [2], the shape of the density of states (DOS) [3], or the quality of the back contact in inorganic solar cells [4]. In this work, we present an analytical model for taking into account absorption induced self-heating in Suns-Voc measurements and validate it for various solar cell technologies such as small molecule organic solar cells, perovskite solar cells, and inorganic solar cells. Furthermore, with an adapted Suns-Voc technique, we are able to not only correctly determine the ideality factor, but also the relevant energy gap of the solar cell, which is especially of interest in the field of novel solar cell technologies. [1] R.A. Sinton and A. Cuevas, EU PVSEC, 1152-1155 (2000) [2] K. Tvingstedt and C. Deibel, Adv. Energy Mater. 6, 1502230 (2016) [3] T. Kirchartz and J. Nelson, Phys. Rev. B 86, 165201 (2012) [4] S. Glunz, J. Nekarda, H. Maeckel et al., EU PVSEC, 849-853 (2007)

  2. Effects of heat treatment on sound absorption coefficients in nanosilver-impregnated and normal solid woods.

    Science.gov (United States)

    Esmailpour, Ayoub; Taghiyari, Hamid Reza; Zolfaghari, Habib

    2017-06-01

    Effects of impregnation with silver nano-suspension as well as heat-treatment on sound absorption coefficients (AC) were studied in tangential direction of five different solid woods based on their importance. AC was measured at two frequencies of 250 and 500 Hz. A 400 ppm nanosuspension was used for the impregnation; silver nanoparticles had a size range of 30-80 nm. Based on the obtained results, the species reacted significantly different in absorbing sound at the two frequencies. Impregnation with nano-suspension substantially decreased AC at the lower frequency of 250 Hz; it did not show any particular trend when AC was measured at the frequency of 500 Hz. Heat treatment significantly increased AC at the frequency of 250 Hz. ACs of mulberry tended to be similar at the two frequencies; in the other four species though, ACs were significantly different. High significant correlations were found in the hardwoods between the ACs measured at the two frequencies.

  3. Saturable absorption of an x-ray free-electron-laser heated solid-density aluminum plasma.

    Science.gov (United States)

    Rackstraw, D S; Ciricosta, O; Vinko, S M; Barbrel, B; Burian, T; Chalupský, J; Cho, B I; Chung, H-K; Dakovski, G L; Engelhorn, K; Hájková, V; Heimann, P; Holmes, M; Juha, L; Krzywinski, J; Lee, R W; Toleikis, S; Turner, J J; Zastrau, U; Wark, J S

    2015-01-09

    High-intensity x-ray pulses from an x-ray free-electron laser are used to heat and probe a solid-density aluminum sample. The photon-energy-dependent transmission of the heating beam is studied through the use of a photodiode. Saturable absorption is observed, with the resulting transmission differing significantly from the cold case, in good agreement with atomic-kinetics simulations.

  4. Magnetohydrodynamic free convection heat and mass transfer of a heat generating fluid past an impulsively started infinite vertical porous plate with Hall current and radiation absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kinyanjui, M.; Kwanza, J.K.; Uppal, S.M. [Jomo Kenyatta University of Agriculture and Technology, Nairobi (Cayman Islands). Dept. of Mathematics and Statistics

    2001-05-01

    Simultaneous heat and mass transfer in unsteady free convection flow with radiation absorption past an impulsively started infinite vertical porous plate subjected to a strong magnetic field is presented. The governing equations for the problem are solved by a finite difference scheme. The influence of the various parameters on the convectively cooled or convectively heated plate in the laminar boundary layer are considered. An analysis of the effects of the parameters on the concentration, velocity and temperature profiles, as well as skin friction and the rates of mass and heat transfer, is done with the aid of graphs and tables. (author)

  5. Marangoni convection flow and heat transfer in pseudoplastic non-newtonian nanofluids with radiation effects and heat generation or absorption effects

    Science.gov (United States)

    Lin, Yanhai; Zheng, Liancun; Zhang, Xinxin

    2012-09-01

    This paper presents a numerical investigation on Marangoni convection flow and heat transfer in pseudoplastic non-Newtonian nanofluids with radiation effects and heat generation or absorption effects. The surface tension is assumed to vary linearly with temperature. The governing partial differential equations are reduced to a series of ordinary differential equations using similarity transformations and the solutions are obtained numerically by the shooting method. Four different types of nanoparticles, namely Cu, Al2O3, CuO and TiO2 are considered by using non-Newtonian CMCwater as a base fluid. The effects of the solid volume fraction, the Power-law number, the Radiation coefficient and the heat generation/absorption coefficient on the velocity and temperature fields are analyzed and discussed in detail.

  6. Performance analysis of double-effect absorption heat pump cycle using NH3/ILs pairs

    OpenAIRE

    Wang, M.; Infante Ferreira, C.A.

    2017-01-01

    Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing H2O or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption chiller or heat pump cycles. In this paper, NH3/IL working pairs are proposed for implementation in parallel double effect heat pump systems. To investigate their performance, a property-prediction method, based on experimental heat capacities and the nonrandom two-liquid (NRTL) activity coefficient model for ...

  7. Calculations of Solar Shortwave Heating Rates due to Black Carbon and Ozone Absorption Using in Situ Measurements

    Science.gov (United States)

    Gao, R. S.; Hall, S. R.; Swartz, W. H.; Spackman, J. R.; Watts, L. A.; Fahey, D. W.; Aikin, K. C.; Shetter, R. E.; Bui, T. P.

    2008-01-01

    Results for the solar heating rates in ambient air due to absorption by black-carbon (BC) containing particles and ozone are presented as calculated from airborne observations made in the tropical tropopause layer (TTL) in January-February 2006. The method uses airborne in situ observations of BC particles, ozone and actinic flux. Total BC mass is obtained along the flight track by summing the masses of individually detected BC particles in the range 90 to 600-nm volume-equivalent diameter, which includes most of the BC mass. Ozone mixing ratios and upwelling and partial downwelling solar actinic fluxes were measured concurrently with BC mass. Two estimates used for the BC wavelength-dependent absorption cross section yielded similar heating rates. For mean altitudes of 16.5, 17.5, and 18.5 km (0.5 km) in the tropics, average BC heating rates were near 0.0002 K/d. Observed BC coatings on individual particles approximately double derived BC heating rates. Ozone heating rates exceeded BC heating rates by approximately a factor of 100 on average and at least a factor of 4, suggesting that BC heating rates in this region are negligible in comparison.

  8. 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.

  9. Theoretical comparison of single-stage and advanced absorption heat transformers used to increase solar pond's temperature

    Energy Technology Data Exchange (ETDEWEB)

    Rivera, W; Best, Roberto [Centro de Investigacion en Energia-UNAM, Temixco, Morelos (Mexico)

    2000-07-01

    Mathematical models of single-stage and advanced absorption heat transformers operating with the water/Carrol{sup T}M mixture were developed to simulate the performance of these systems coupled to a solar pond in order to increase the temperature of the useful heat produced by solar ponds. The results showed that the single-stage and the double absorption heat transformer are the most promising configuration to be coupled to solar ponds. With single-stage heat transformers it is possible to increase solar pond's temperature until 50 Celsius degrees with coefficients of performance of about 0.48 and with double absorption heat transformers until 100 Celsius degrees with coefficients of performance of 0.33. [Spanish] Se desarrollaron modelos matematicos de una sola etapa y transformadores avanzados de absorcion de calor operando con la mezcla agua/Carrol{sup T}M para simular el rendimiento de estos sistemas acoplados a un estanque solar con el objeto de aumentar la temperatura del calor util producido por los estanques solares. Los resultados mostraron que la etapa sencilla y el transformador de calor de absorcion doble son la configuracion mas prometedora para ser acoplado a estanques solares. Con los transformadores de calor de una sola etapa es posible aumentar la temperatura del estanque solar hasta 50 grados Celsius con coeficientes de rendimiento de alrededor de 0.48 y con transformadores de calor de doble absorcion hasta 100 grados Celsius con coeficientes de rendimiento de 0.33.

  10. Framing the performance of heat absorption/generation and thermal radiation in chemically reactive Darcy-Forchheimer flow

    Science.gov (United States)

    Hayat, T.; Shah, Faisal; Khan, Muhammad Ijaz; Alsaedi, A.

    The present work aims to report the consequences of heterogeneous-homogeneous reactions in Darcy-Forchheimer flow of Casson material bounded by a nonlinear stretching sheet of variable thickness. Nonlinear stretched surface with variable thickness is the main agent for MHD Darcy-Forchheimer flow. Impact of thermal radiation and non-uniform heat absorption/generation are also considered. Flow in porous space is characterized by Darcy-Forchheimer flow. It is assumed that the homogeneous process in ambient fluid is governed by first order kinetics and the heterogeneous process on the wall surface is given by isothermal cubic autocatalator kinetics. The governing nonlinear ordinary differential equations are solved numerically. Effects of physical variables such as thickness, Hartman number, inertia and porous, radiation, Casson, heat absorption/generation and homogeneous-heterogeneous reactions are investigated. The variations of drag force (skin friction) and heat transfer rate (Nusselt number) for different interesting variables are plotted and discussed.

  11. Performance Evaluation of a Lithium-Chloride Absorption Refrigeration and an Assessment of Its Suitability for Biomass Waste Heat

    Directory of Open Access Journals (Sweden)

    Sacha Oberweis

    2012-10-01

    Full Text Available This paper presents a computer model that will evaluate the performance of a thermo-chemical accumulator. The model is based on operational data such as temperatures and flow rates. The ultimate goal for this model is to estimate the coefficient of performance (COP of this unit when run on hot water from biomass combustion as the heat source. The outputs of the model are verified by comparing the simulation of the actual machine with published experimental data. The computed results for cooling COP are within 10% of the measured data. The simulations are all run for heat load temperatures varying between 80 °C and 110 °C. As expected, simulation results showed an increase in COP with increased heat source temperatures. The results demonstrate that the potential of combined solar and biomass combustion as a heat source for absorption cooling/heating in climates with low solar radiation can be coupled with biomass waste.

  12. Hafnium nitride films for thermoreflectance transducers at high temperatures: Potential based on heating from laser absorption

    Science.gov (United States)

    Rost, Christina M.; Braun, Jeffrey; Ferri, Kevin; Backman, Lavina; Giri, Ashutosh; Opila, Elizabeth J.; Maria, Jon-Paul; Hopkins, Patrick E.

    2017-10-01

    Time domain thermoreflectance (TDTR) and frequency domain thermoreflectance (FDTR) are common pump-probe techniques that are used to measure the thermal properties of materials. At elevated temperatures, transducers used in these techniques can become limited by melting or other phase transitions. In this work, time domain thermoreflectance is used to determine the viability of HfN thin film transducers grown on SiO2 through measurements of the SiO2 thermal conductivity up to approximately 1000 K. Further, the reliability of HfN as a transducer is determined by measuring the thermal conductivities of MgO, Al2O3, and diamond at room temperature. The thermoreflectance coefficient of HfN was found to be 1.4 × 10-4 K-1 at 800 nm, one of the highest thermoreflectance coefficients measured at this standard TDTR probe wavelength. Additionally, the high absorption of HfN at 400 nm is shown to enable reliable laser heating to elevate the sample temperature during a measurement, relative to other transducers.

  13. Effect of heat treatment on microwave absorption properties of Ni–Zn–Mg–La ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yi, E-mail: liuyi5556@sina.com; Wei, Shicheng; Xu, Binshi; Wang, Yujiang; Tian, Haoliang; Tong, Hui

    2014-01-15

    Spinel structure Ni–Zn–Mg–La ferrites have been prepared by the sol–gel route and investigated as a radar absorbing material (RAM) in a frequency range of 1–18 GHz. The structure and morphological studies on the nanoparticles of the ferrites have been carried out using X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The complex permeability and complex permittivity are measured by a network analyzer. The electromagnetic wave loss and microwave absorbing property are studied as a function of frequency, annealing temperature and thickness of the absorber. The results indicate that electromagnetic wave loss of the ferrite only annealed at 850 °C shows two peaks. The reflection loss varies with the change of the annealing temperature. The absorber annealed at 850 °C exhibits the best microwave absorbing properties, which is suitable for microwave absorption materials. - Highlights: • Spinel structure Ni–Zn–Mg–La ferrite has been first prepared by sol–gel auto combustion route. • The effects of heat treatment on structure and microwave properties for the ferrite are investigated. • Electromagnetic loss and reflection loss property of the ferrite system are greatly improved by increasing annealing temperature.

  14. Design of serially connected ammonia-water hybrid absorption-compression heat pumps for district heating with the utilisation of a geothermal heat source

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2016-01-01

    to supply 7.2 MW heat at 85 °C utilizing a geothermal heat source at 73 °C. Both the heat source and heat sink experience a large temperature change over the heat transfer process, of which a significant part may be achieved by direct heat exchange. First a generic study with a simple representation...

  15. Framing the performance of heat absorption/generation and thermal radiation in chemically reactive Darcy-Forchheimer flow

    Directory of Open Access Journals (Sweden)

    T. Hayat

    Full Text Available The present work aims to report the consequences of heterogeneous-homogeneous reactions in Darcy-Forchheimer flow of Casson material bounded by a nonlinear stretching sheet of variable thickness. Nonlinear stretched surface with variable thickness is the main agent for MHD Darcy-Forchheimer flow. Impact of thermal radiation and non-uniform heat absorption/generation are also considered. Flow in porous space is characterized by Darcy-Forchheimer flow. It is assumed that the homogeneous process in ambient fluid is governed by first order kinetics and the heterogeneous process on the wall surface is given by isothermal cubic autocatalator kinetics. The governing nonlinear ordinary differential equations are solved numerically. Effects of physical variables such as thickness, Hartman number, inertia and porous, radiation, Casson, heat absorption/generation and homogeneous-heterogeneous reactions are investigated. The variations of drag force (skin friction and heat transfer rate (Nusselt numberfor different interesting variables are plotted and discussed. Keywords: Casson fluid, Variable sheet thickness, Darcy-Forchheimer flow, Homogeneous-heterogeneous reactions, Heat generation/absorption, Thermal radiation

  16. Simulation and experimental study of solar-absorption heat transformer integrating with two-stage high temperature vapor compression heat pump

    Directory of Open Access Journals (Sweden)

    Nattaporn Chaiyat

    2014-11-01

    Full Text Available In this study, simulation and experiment studies of a 10 kW solar H2O–LiBr absorption heat transformer (AHT integrating with a two-stage vapor compression heat pump (VCHP were carried out. The whole system was named as compression/absorption heat transformer (CAHT. The VCHP was used to recover rejected heat at the AHT condenser which was transferred back to the AHT evaporator at a higher temperature. The AHT unit took solar heat from a set of flat-plate solar collectors in parallel connection. R-134a and R-123 were refrigerants in the VCHP cycle. From the simulation, the total cycle coefficient (COP of the solar-CAHT was 0.71 compared with 0.49 of the normal solar-AHT. From the experiment, the total cycle COPs of the solar-CAHT and the solar-AHT were 0.62 and 0.39, respectively. The experimental results were lower than those of the simulated models due to the oversize of the experimental compressor. The annual expense of the solar-CAHT was found to be 5113 USD which was lower than 5418 USD of the solar-AHT. So it could be concluded that the modified unit was beneficial than the normal unit in terms of energy efficiency and economic expense.

  17. High Efficiency Water Heating Technology Development Final Report, Part II: CO2 and Absorption-Based Residential Heat Pump Water Heater Development

    Energy Technology Data Exchange (ETDEWEB)

    Gluesenkamp, Kyle R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Patel, Viral K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mandel, Bracha T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); de Almeida, Valmor F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-01

    The two objectives of this project were to 1.demonstrate an affordable path to an ENERGY STAR qualified electric heat pump water heater (HPWH) based on low-global warming potential (GWP) CO2 refrigerant, and 2.demonstrate an affordable path to a gas-fired absorption-based heat pump water heater with a gas energy factor (EF) greater than 1.0. The first objective has been met, and the project has identified a promising low-cost option capable of meeting the second objective. This report documents the process followed and results obtained in addressing these objectives.

  18. Numerical solution of Williamson fluid flow past a stretching cylinder and heat transfer with variable thermal conductivity and heat generation/absorption

    Directory of Open Access Journals (Sweden)

    M. Y. Malik

    2016-03-01

    Full Text Available In this article, Williamson fluid flow and heat transfer over a stretching cylinder is discussed. The thermal conductivity is assumed to be vary linearly with temperature. Heat generation/absorption effects are also taken into account. Modeled partial differential equations are converted into ordinary differential form by using appropriate transformations. Shooting method in conjunction with Runge-Kutta-Fehlberg method is used to find the solution of the problem. Moreover, the effects of different flow parameters γ, λ, ϵ, β and Pr on velocity and temperature profiles are shown graphically. Local Nusselt number and skin friction coefficient are shown in tabular and graphical form.

  19. Changes in the heating and cooling energy use in buildings due to lowering the surface solar absorptance of roofs

    Energy Technology Data Exchange (ETDEWEB)

    Griggs, E.I.; Courville, G.E.

    1989-02-01

    This report addresses how changing a flat roof's solar absorptance alters the energy required to heat and cool a building. The increase in a roof's surface temperature due to insolation increases the building's heat gain during the summer and reduces its heat loss during the winter. This study examines this counteracting influence on annual HVAC energy use. The report reviews pertinent background and presents computed changes in heating and cooling needs obtained using the computer code, DOE 2.1B. All computations were made corresponding to a reduction in a flat roof's solar absorptance from 0.8 to 0.3. They were made for two different buildings using TMY weather data for twenty cities within the United States; they were also made for a third building using weather data for five US cities. Computed annual changes in building heating and cooling energy use are presented in the form of bar charts for each location. Calculations were made for three different roof insulation levels. The change in annual energy use caused by the reduction in solar absorptance decreases with increased roof insulation. This effect is depicted graphically for representative cases. Incorporating realistic HVAC system performance and using a particular energy cost scenario based on use of natural gas for heating and cooling via an electrically driven unit, the best cost savings occurred for locations in the Southwest and were equivalent to approximately the costs of 1 Kw-hr of electrical energy per square foot of flat roof surface. 16 refs., 18 figs., 29 tabs.

  20. Use of process steam in vapor absorption refrigeration system for cooling and heating applications: An exergy analysis

    Directory of Open Access Journals (Sweden)

    S. Anand

    2016-12-01

    Full Text Available The exponential increase in cost of conventional fuels shifts the interest toward the use of alternative as well waste energy sources for the operation of refrigeration and air-conditioning units. The present study therefore analyzes the performance of a process steam-operated vapor absorption system for cooling and heating applications using ammonia and water as working fluids based on first and second laws of thermodynamics. A mathematical model has been developed based on exergy analysis to investigate the performance of the system. The different performance parameters such as coefficient of performance (COP and exergetic efficiency of absorption system for cooling and heating applications are also calculated under different operating conditions. The results obtained show that cooling and heating COP along with second law efficiency (exergy efficiency increases with the heat source temperature at constant evaporator, condenser, and absorber temperature. Also, COP as well as exergy efficiency increases with an increase in the evaporator temperature at constant generator, condenser, and absorber temperature. The effect of ambient temperature on the exergetic efficiency for cooling and heating applications is also studied. The results obtained from the simulation studies can be used to optimize different components of the system so that the performance can be improved significantly.

  1. Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

    Science.gov (United States)

    Lahiri, B. B.; Ranoo, Surojit; Philip, John

    2017-11-01

    Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ~25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and the

  2. Technical and Economic Working Domains of Industrial Heat Pumps: Part 2 - Ammonia-Water Hybrid Absorption-Compression Heat Pumps

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2014-01-01

    of the zeotropic mixture, ammonia-water. To evaluate to which extent these advantages can be translated into feasible heat pump solutions, the working domain of the HACHP is investigated based on technical and economic constraints. The HACHP working domain is compared to that of the best possible vapour...

  3. Technical and economic working domains of industrial heat pumps: Part 2 - ammonia-water hybrid absorption-compression heat pumps

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2015-01-01

    change of the zeotropic mixture, ammonia-water. To evaluate to which extent these advantages can be translated into feasible heat pump solutions, the working domain of the HACHP is investigated based on technical and economic constraints. The HACHP working domain is compared to that of the best available...

  4. Absorption of CO2-NH3-H2O mixture in mini-channel heat exchangers

    NARCIS (Netherlands)

    Shi, Liang; Gudjonsdottir, V.; Infante Ferreira, C.A.; Rexwinkel, Glenn; Kiss, Anton A.

    2017-01-01

    Compression resorption heat pumps (CRHP) are a promising option to upgrade waste heat from industry. Alternative working fluids can further improve the efficiency of CRHP. The ternary mixture NH3-CO2-H2O has been identified as a promising working fluid for CRHP and has the potential to further

  5. Three-dimensional flow of an oldroyd-B fluid with variable thermal conductivity and heat generation/absorption.

    Directory of Open Access Journals (Sweden)

    Sabir Ali Shehzad

    Full Text Available This paper looks at the series solutions of three dimensional boundary layer flow. An Oldroyd-B fluid with variable thermal conductivity is considered. The flow is induced due to stretching of a surface. Analysis has been carried out in the presence of heat generation/absorption. Homotopy analysis is implemented in developing the series solutions to the governing flow and energy equations. Graphs are presented and discussed for various parameters of interest. Comparison of present study with the existing limiting solution is shown and examined.

  6. Mixed convection and heat generation/absorption aspects in MHD flow of tangent-hyperbolic nanoliquid with Newtonian heat/mass transfer

    Science.gov (United States)

    Qayyum, Sajid; Hayat, Tasawar; Shehzad, Sabir Ali; Alsaedi, Ahmed

    2018-03-01

    This article concentrates on the magnetohydrodynamic (MHD) stagnation point flow of tangent hyperbolic nanofluid in the presence of buoyancy forces. Flow analysis caused due to stretching surface. Characteristics of heat transfer are examined under the influence of thermal radiation and heat generation/absorption. Newtonian conditions for heat and mass transfer are employed. Nanofluid model includes Brownian motion and thermophoresis. The governing nonlinear partial differential systems of the problem are transformed into a systems of nonlinear ordinary differential equations through appropriate variables. Impact of embedded parameters on the velocity, temperature and nanoparticle concentration fields are presented graphically. Numerical computations are made to obtain the values of skin friction coefficient, local Nusselt and Sherwood numbers. It is concluded that velocity field enhances in the frame of mixed convection parameter while reverse situation is observed due to power law index. Effect of Brownian motion parameter on the temperature and heat transfer rate is quite reverse. Moreover impact of solutal conjugate parameter on the concentration and local Sherwood number is quite similar.

  7. The available heat source influence on the operation of one stage absorption refrigeration systems

    OpenAIRE

    Stanciu, Camelia; Stanciu, Dorin; Feidt, Michel; Costea, Monica

    2013-01-01

    International audience; On propose de présenter le fonctionnement d’une installation frigorifique à absorption alimentée par l’énergie thermique fournie par un captateur solaire plan. Le régime de fonctionnement optimum est visé, pour lequel on désire calculer la surface nécessaire du captateur solaire.

  8. Solar powered absorption cycle heat pump using phase change materials for energy storage

    Science.gov (United States)

    Middleton, R. L.

    1972-01-01

    Solar powered heating and cooling system with possible application to residential homes is described. Operating principles of system are defined and illustration of typical energy storage and exchange system is provided.

  9. On the pressure drop in Plate Heat Exchangers used as desorbers in absorption chillers

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Hernando, N.; de Vega, M. [Energy System Engineering (ISE), Departamento de Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad, 30, 28911 Leganes, Madrid (Spain); Almendros-Ibanez, J.A. [Escuela de Ingenieros Industriales de Albacete, Departamento de Mecanica Aplicada e Ingenieria de Proyectos, Universidad de Castilla La Mancha, Campus Universitario s/n, 02071 Albacete (Spain); Renewable Energy Research Institute, c/de la Investigacion s/n, 02071 Albacete (Spain); Ruiz, G. [Energy Efficiency and Renewables Department, Tecnicas Reunidas S.A., C/Arapiles No. 13, 10a, 28015 Madrid (Spain)

    2011-02-15

    The influence of the pressure drop in Plate Heat Exchangers (PHE) in the boiling temperature of LiBr-H{sub 2}O and NH{sub 3}-H{sub 2}O solutions is studied. For the NH{sub 3}-H{sub 2}O solution, the pressure drop-temperature saturation relationship estates that high pressure drops can be allowed in the solution with negligible changes in the saturation temperature, and in the PHE performance. Besides, in the case of the LiBr-H{sub 2}O solution, as the working pressure is usually very low, the analysis of the pressure drop must be taken as a main limiting parameter for the use of Plate Heat Exchangers as vapour generators. In this case, the pressure drop may considerably change the boiling temperature of the solution entering the heat exchanger and therefore a higher heating fluid temperature may be required. A guideline to design these systems is proposed. (author)

  10. Combined absorption power and refrigeration systems driven by low and mid-grade heat sources

    OpenAIRE

    Ayou, Dereje Sendeku

    2014-01-01

    Low and mid-grade heat sources (< 300 °C), such as solar thermal, geothermal and waste heat from various thermal processes are abundantly available. Air-conditioning, refrigeration and electricity are useful forms of energy products, usually produced using separate energy conversion technologies. Most end-users need at least dual energy products: typical example could be buildings applications. The combined production of electricity (decentralized) and cold using efficient thermally-driven en...

  11. Regional Climate Zone Modeling of a Commercial Absorption Heat Pump Hot Water Heater Part 1: Southern and South Central Climate Zones

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick J [ORNL; Shen, Bo [ORNL; Keinath, Christopher M. [Stone Mountain Technologies, Inc., Johnson City; Garrabrant, Michael A. [Stone Mountain Technologies, Inc., Johnson City

    2016-01-01

    Commercial hot water heating accounts for approximately 0.78 Quads of primary energy use with 0.44 Quads of this amount from natural gas fired heaters. An ammonia-water based commercial absorption system, if fully deployed, could achieve a high level of savings, much higher than would be possible by conversion to the high efficiency nonheat-pump gas fired alternatives. In comparison with air source electric heat pumps, the absorption system is able to maintain higher coefficients of performance in colder climates. The ammonia-water system also has the advantage of zero Ozone Depletion Potential and low Global Warming Potential. A thermodynamic model of a single effect ammonia-water absorption system for commercial space and water heating was developed, and its performance was investigated for a range of ambient and return water temperatures. This allowed for the development of a performance map which was then used in a building energy modeling software. Modeling of two commercial water heating systems was performed; one using an absorption heat pump and another using a condensing gas storage system. The energy and financial savings were investigated for a range of locations and climate zones in the southern and south central United States. A follow up paper will analyze northern and north/central regions. Results showed that the system using an absorption heat pump offers significant savings.

  12. Space Launch System Base Heating Test: Tunable Diode Laser Absorption Spectroscopy

    Science.gov (United States)

    Parker, Ron; Carr, Zak; MacLean, Mathew; Dufrene, Aaron; Mehta, Manish

    2016-01-01

    This paper describes the Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurement of several water transitions that were interrogated during a hot-fire testing of the Space Launch Systems (SLS) sub-scale vehicle installed in LENS II. The temperature of the recirculating gas flow over the base plate was found to increase with altitude and is consistent with CFD results. It was also observed that the gas above the base plate has significant velocity along the optical path of the sensor at the higher altitudes. The line-by-line analysis of the H2O absorption features must include the effects of the Doppler shift phenomena particularly at high altitude. The TDLAS experimental measurements and the analysis procedure which incorporates the velocity dependent flow will be described.

  13. Enhanced specific absorption rate of bi-magnetic nanoparticles for heating applications

    Energy Technology Data Exchange (ETDEWEB)

    Hammad, Mohaned; Hempelmann, Rolf, E-mail: r.hempelmann@mx.uni-saarland.de

    2017-02-15

    Truncated octahedron bi-magnetic core/shell nanoparticles of Zn{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}@Zn{sub 0.4}Mn{sub 0.6}Fe{sub 2}O{sub 4} with different size distributions have been synthesized, and their structural and magnetic properties have been studied. The structure and morphology of the core/shell nanostructures were established by using X-ray diffraction, and transmission electron microscopy. Dark field-TEM and X-ray photoelectron spectroscopy results confirmed the formation of bi-magnetic core/shell nanoparticles. The synthesized nanoparticles are superparamagnetic at room temperature. The Curie temperature increases with the increase of particle size from 360 K to 394 K. The experimental results showed that core/shell nanoparticles have a higher specific absorption rate compared to the core ones. These nanoparticles are interfacial exchange coupled between hard and soft magnetic phases. We demonstrated that the specific absorption rate could be tuned by the concentration of precursor and the synthesis time. - Highlights: • Zn{sub 0.4}Co{sub 0.6}Fe{sub 2}O{sub 4}@Zn{sub 0.4}Mn{sub 0.6}Fe{sub 2}O{sub 4} nanoparticles were synthesized by seed-mediated growth method. • Exchange-coupling between magnetic hard and soft phase of the magnetic nanoparticles affects the specific absorption rate. • The specific absorption rate could be tuned by the concentration of precursor and the synthesis time. • An increase of the core/shell magnetic nanoparticles size resulted in the increase of Curie temperature.

  14. Open absorption heat pump for waste heat utilization in the forest industry. A study of technical and economic potential; Oeppen absorptionsvaermepump foer uppgradering av spillvaerme fraan skogsindustrin. Studie av teknisk och ekonomisk potential

    Energy Technology Data Exchange (ETDEWEB)

    Westermark, Mats; Vidlund, Anna

    2006-02-15

    Waste heat from the forest industry is mainly humid air or humid flue gases with somewhat too low dew point for direct use as district heating or for other qualified purposes. Upgrading of the temperature by heat pumps is thus often necessary for the full use of the waste heat. This study evaluates an open absorption heat, based on hygroscopic condensation. The hygroscopic condenser has the potential to replace mechanical heat pumps or conventional absorption heat pumps (based on lithium bromide) for the upgrading of heat from humid gases. The goal for the project is to evaluate technology and potential for an open absorption heat pump for heat recovery from humid gases in the forest industry. In an open heat pump the humid gas is brought in direct contact with the hygroscopic liquid (whereas a conventional heat pump uses an intermediate circuit with evaporation of water in the evaporator). The direct contact makes it possible to recover the heat at a higher temperature than the dew point of the humid gas without the use of evaporator. The target group for the study is the forest industry and its suppliers of technology and knowledge. The study has been carried out in cooperation with representatives from the forest industry and from suppliers of equipment. The study shows that the forest industry has good potential to upgrade waste heat from humid air to district heating. The waste heat can be extracted from various humid gases such as exit air from paper machines, wood driers, green liquid quenchers and flue gases from soda boilers, mesa kilns, bark-fired boilers and gas engines. Hygroscopic condensation is considered to give economic and environmental advantages compared to conventional absorption heat pumps due to much less consumption of driving heat. An interesting special case is the regeneration of the hygroscopic medium by direct contact with hot flue gases and for this application a patent application has been filed. Upgrading of waste heat to process

  15. On the influence of heat conduction on paramagnetic dispersion and absorption curves

    NARCIS (Netherlands)

    Valkering, T.P.; van der Marel, L.C.

    1970-01-01

    Starting from the model of Casimir and Du Pré, which has been refined by Eisenstein, an expression for the differential paramagnetic susceptibility of a paramagnetic material, placed in a (gaseous or liquid) bath, is derived. This expression contains among others the coefficient of heat conduction

  16. Monitoring Temperature in High Enthalpy Arc-heated Plasma Flows using Tunable Diode Laser Absorption Spectroscopy

    Science.gov (United States)

    Martin, Marcel Nations; Chang, Leyen S.; Jeffries, Jay B.; Hanson, Ronald K.; Nawaz, Anuscheh; Taunk, Jaswinder S.; Driver, David M.; Raiche, George

    2013-01-01

    A tunable diode laser sensor was designed for in situ monitoring of temperature in the arc heater of the NASA Ames IHF arcjet facility (60 MW). An external cavity diode laser was used to generate light at 777.2 nm and laser absorption used to monitor the population of electronically excited oxygen atoms in an air plasma flow. Under the assumption of thermochemical equilibrium, time-resolved temperature measurements were obtained on four lines-of-sight, which enabled evaluation of the temperature uniformity in the plasma column for different arcjet operating conditions.

  17. On Convective Dusty Flow Past a Vertical Stretching Sheet with Internal Heat Absorption

    Directory of Open Access Journals (Sweden)

    Raj Nandkeolyar

    2013-01-01

    Full Text Available The steady two-dimensional boundary layer flow of a viscous, incompressible, and electrically conducting dusty fluid past a vertical permeable stretching sheet under the influence of a transverse magnetic field with the viscous and Joule dissipation is investigated. The fluid particles are assumed to be heat absorbing and the temperature at the surface of the sheet is a result of convective heating. The governing nonlinear partial differential equations are transformed to a set of highly nonlinear coupled ordinary differential equations using a suitable similarity transformation and the resulting system is then solved numerically. It is found inter alia that the contributions of viscous and Joule dissipation in the flow are to increase the thickness of the thermal boundary layer.

  18. Effect of heat treatment on microwave absorption properties of Ni-Zn-Mg-La ferrite nanoparticles

    Science.gov (United States)

    Liu, Yi; Wei, Shicheng; Xu, Binshi; Wang, Yujiang; Tian, Haoliang; Tong, Hui

    2014-01-01

    Spinel structure Ni-Zn-Mg-La ferrites have been prepared by the sol-gel route and investigated as a radar absorbing material (RAM) in a frequency range of 1-18 GHz. The structure and morphological studies on the nanoparticles of the ferrites have been carried out using X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The complex permeability and complex permittivity are measured by a network analyzer. The electromagnetic wave loss and microwave absorbing property are studied as a function of frequency, annealing temperature and thickness of the absorber. The results indicate that electromagnetic wave loss of the ferrite only annealed at 850 °C shows two peaks. The reflection loss varies with the change of the annealing temperature. The absorber annealed at 850 °C exhibits the best microwave absorbing properties, which is suitable for microwave absorption materials.

  19. Development of the Hybrid Operation Method of a Multi-Geothermal Heat Pump System and Absorption Chiller-Heater

    Directory of Open Access Journals (Sweden)

    Young-Ju Jung

    2015-08-01

    Full Text Available Considerable efforts have been made to reduce the energy consumption of buildings due to the energy crisis, and, the Korean government has supported the use of renewable energy through various grants. Among the possible renewable energy sources, geothermal energy can be used regardless of the outside weather. Therefore, energy consumption can be reduced considerably in summer and winter. Despite the increasing use of renewable energy, the use of renewables has not been operating appropriately. Therefore, this study examined some of the problems of the operation of renewable energy and some possible improvements. The aim of the study is to evaluate a building containing an actual installed multi-geothermal heat pump (Multi-GHP system, in terms of the energy efficiency. In addition, this study evaluated the present control system and the method of complex operation regarding existing heat sources systems and GHP systems through a simulation. The results can be regarded as the result of a hybrid operation method for the improvement of an existing operation. Therefore, the Multi-GHP system energy use of a hybrid operation condition of the Multi-GHP systems and the absorption (ABS chiller-heater system was reduced compared to the operation condition of the Multi-GHP system, and the total energy consumption of the heat source equipment was reduced. The proposed operation plan was evaluated after applying the system to a building. These results showed that the efficient operation of a Multi-GHP hybrid operation method is possible. As a result, the GHP energy use of Multi-GHP systems and the ABS chiller-heater system was reduced by 30% compared to existing operation and the total energy consumption of heat source equipment was reduced by 78%.

  20. Non-Darcy flow of water-based carbon nanotubes with nonlinear radiation and heat generation/absorption

    Science.gov (United States)

    Hayat, T.; Ullah, Siraj; Khan, M. Ijaz; Alsaedi, A.; Zaigham Zia, Q. M.

    2018-03-01

    Here modeling and computations are presented to introduce the novel concept of Darcy-Forchheimer three-dimensional flow of water-based carbon nanotubes with nonlinear thermal radiation and heat generation/absorption. Bidirectional stretching surface induces the flow. Darcy's law is commonly replace by Forchheimer relation. Xue model is implemented for nonliquid transport mechanism. Nonlinear formulation based upon conservation laws of mass, momentum and energy is first modeled and then solved by optimal homotopy analysis technique. Optimal estimations of auxiliary variables are obtained. Importance of influential variables on the velocity and thermal fields is interpreted graphically. Moreover velocity and temperature gradients are discussed and analyzed. Physical interpretation of influential variables is examined.

  1. Heat generation/absorption and nonlinear radiation effects on stagnation point flow of nanofluid along a moving surface

    Science.gov (United States)

    Soomro, Feroz Ahmed; Haq, Rizwan Ul; Al-Mdallal, Qasem M.; Zhang, Qiang

    2018-03-01

    In this study, heat generation/absorption effects are studied in the presence of nonlinear thermal radiation along a moving slip surface. Uniform magnetic field and convective condition along the stretching surface are adjusted to deal the slip mechanisms in term of Brownian motion and thermophoresis for nanofluid. The mathematical model is constructed in the form of coupled partial differential equations. By introducing the suitable similarity transformation, system of coupled nonlinear ordinary differential equations are obtained. Finite difference approach is implemented to obtain the unknown functions of velocity, temperature, nanoparticle concentration. To deduct the effects at the surface, physical quantities of interest are computed under the effects of controlled physical parameters. Present numerical solutions are validated via numerical comparison with existing published work for limiting cases. Present study indicates that due to increase in both Brownian motion and thermophoresis, the Nusselt number decreases while Sherwood number shows the gradual increase.

  2. Effects of biomass burning on climate, accounting for heat and moisture fluxes, black and brown carbon, and cloud absorption effects

    Science.gov (United States)

    Jacobson, Mark Z.

    2014-07-01

    This paper examines the effects on climate and air pollution of open biomass burning (BB) when heat and moisture fluxes, gases and aerosols (including black and brown carbon, tar balls, and reflective particles), cloud absorption effects (CAEs) I and II, and aerosol semidirect and indirect effects on clouds are treated. It also examines the climate impacts of most anthropogenic heat and moisture fluxes (AHFs and AMFs). Transient 20 year simulations indicate BB may cause a net global warming of 0.4 K because CAE I ( 32% of BB warming), CAE II, semidirect effects, AHFs ( 7%), AMFs, and aerosol absorption outweigh direct aerosol cooling and indirect effects, contrary to previous BB studies that did not treat CAEs, AHFs, AMFs, or brown carbon. Some BB warming can be understood in terms of the anticorrelation between instantaneous direct radiative forcing (DRF) changes and surface temperature changes in clouds containing absorbing aerosols. BB may cause 250,000 (73,000-435,000) premature mortalities/yr, with >90% from particles. AHFs from all sources and AMFs + AHFs from power plants and electricity use each may cause a statistically significant +0.03 K global warming. Solar plus thermal-IR DRFs were +0.033 (+0.027) W/m2 for all AHFs globally without (with) evaporating cooling water, +0.009 W/m2 for AMFs globally, +0.52 W/m2 (94.3% solar) for all-source BC outside of clouds plus interstitially between cloud drops at the cloud relative humidity, and +0.06 W/m2 (99.7% solar) for BC inclusions in cloud hydrometeor particles. Modeled post-1850 biomass, biofuel, and fossil fuel burning, AHFs, AMFs, and urban surfaces accounted for most observed global warming.

  3. Free convective heat transfer with hall effects, heat absorption and chemical reaction over an accelerated moving plate in a rotating system

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S.M., E-mail: hussain.modassir@yahoo.com [Department of Mathematics, OP Jindal University, Raigarh 496109 (India); Jain, J., E-mail: jj.28481@gmail.com [Department of Mathematics, OP Jindal University, Raigarh 496109 (India); Seth, G.S., E-mail: gsseth_ism@yahoo.com [Department of Applied Mathematics, Indian School of Mines, Dhanbad 826004 (India); Rashidi, M.M., E-mail: mm_rashidi@yahoo.com [Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management System, Tongji University, Shanghai 201804 (China)

    2017-01-15

    The unsteady MHD free convective heat and mass transfer flow of an electrically conducting, viscous and incompressible fluid over an accelerated moving vertical plate in the presence of heat absorption and chemical reaction with ramped temperature and ramped surface concentration through a porous medium in a rotating system is studied, taking Hall effects into account. The governing equations are solved analytically with the help of Laplace transform technique. The unified closed-form expressions are obtained for fluid velocity, fluid temperature, species concentration, skin friction, Nusselt number and Sherwood numbers. The effects of various parameters on fluid velocity, fluid temperature and species concentration are discussed by graphs whereas numerical values of skin friction, Nusselt and Sherwood numbers are presented in tabular form for different values of pertinent flow parameters. The numerical results are also compared with free convective flow near ramped temperature plate with ramped surface concentration with the corresponding flow near isothermal plate with uniform surface concentration. - Highlights: • Magnetic field, Hall current, rotation and chemical reaction play vital role on flow field. • Hall current tends to accelerate secondary fluid velocity in the boundary layer region. • Rotation tends to retard primary fluid velocity throughout the boundary layer region. • Rotation and chemical reaction tend to enhance primary skin friction. • Solutal buoyancy force and permeability of medium reduce primary skin friction.

  4. Femtosecond laser absorption, heat propagation, and damage threshold analysis for Au coating on metallic substrates

    Science.gov (United States)

    Suslova, Anastassiya; Hassanein, Ahmed

    2017-11-01

    The role of metallic substrates as a heat sink for thin layer gold coatings in double-layered optical components exposed to the ultrashort pulsed laser was investigated with the focus on the impact of the gold layer thickness. A two dimensional FEMTO-2D computational code for solid metallic targets with two-layered assemblies has been developed. The model is then used to simulate targets response to fs laser pulses at near damage threshold fluence and to determine the target damage threshold depending on its structure and the substrate material. Considering temperature dependent optical properties of a gold allowed us to make quantitative estimation of the damage threshold unlike many other models. The simulations show decreasing heat sink effect of the substrate with increasing coating thickness until it becomes negligible for 200 nm gold layer. Preliminary results show that a maximum improvement of the damage threshold of about 10% compared to a pure gold target is predicted for 50 nm gold coatings on two substrate materials: copper and nickel.

  5. Performance Analysis of Rectifier in NH3-H2O Absorption Heat Pump

    Science.gov (United States)

    Tsujimori, Atushi; Ozaki, Eiichi; Nakao, Kazushige

    Characteristic of stripping section of packed-tower type rectifierwas presentedin previous paper. In order to improve NH3 concentration inrefrigerant vapor, enriching section is considered effective. Refrigerant vapor from stripping section of rectifier and reflux solution from partial condenser flow into this section, and the proportion of solution flow rate to vapor flow rate of enriching section called reflux ratio is much smaller than that of stripping section. So the effect of reflux ratio on rectification process might be larger. In this paper the effect of reflux flow rate and NH3 concentration in reflux solution is investigated experimentally. As a result, it was derived that the performance of enriching section was mainly decided by reflux ratio. Then the effect of rectification performance on heat rate of partial condenser and evaporator was evaluated using the experimental result of enriching section performance.

  6. Absorption heat pump integrated in an effluent purification system; Bomba de calor por absorcion integrada a un sistema de purificacion de efluentes

    Energy Technology Data Exchange (ETDEWEB)

    Santoyo, Socrates; Siqueiros, Javier; Heard, Christopher; Santoyo, Edgar [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The results derived of the integration of an absorption heat pump to an industrial effluents purification system, are presented. The advantages of these heat pumps with respect to heat pumps by mechanical compression of vapor, as well as the advantages in using absorption heat pumps in simple distillation systems, are mentioned. Finally, a description is made of the equipment designed and built, as well as the results obtained in a preliminary test. [Espanol] Se presentan los resultados derivados de la integracion de una bomba de calor por absorcion a un sistema de purificacion de efluentes industriales. Se mencionan las ventajas de este tipo de bombas de calor con respecto a las de calor por compresion mecanica de vapor, asi como las ventajas de usar bombas de calor en sistemas de destilacion simple. Finalmente, se describe el equipo disenado y construido, asi como los resultados obtenidos de una prueba preliminar.

  7. On the performance of heat absorption/generation and thermal stratification in mixed convective flow of an Oldroyd-B fluid

    Directory of Open Access Journals (Sweden)

    Tasawar Hayat

    2017-12-01

    Full Text Available This investigation explores the thermally stratified stretchable flow of an Oldroyd-B material bounded by a linear stretched surface. Heat transfer characteristics are addressed through thermal stratification and heat generation/absorption. Formulation is arranged for mixed convection. Application of suitable transformations provides ordinary differential systems through partial differential systems. The homotopy concept is adopted for the solution of nonlinear differential systems. The influence of several arising variables on velocity and temperature is addressed. Besides this, the rate of heat transfer is calculated and presented in tabular form. It is noticed that velocity and Nusselt number increase when the thermal buoyancy parameter is enhanced. Moreover, temperature is found to decrease for larger values of Prandtl number and heat absorption parameter. Comparative analysis for limiting study is performed and excellent agreement is found.

  8. Thermal radiation and heat generation/absorption effects on viscoelastic double-diffusive convection from an isothermal sphere in porous media

    Directory of Open Access Journals (Sweden)

    S. Abdul Gaffar

    2015-09-01

    Full Text Available Buoyancy-driven convective heat and mass transfer in boundary layer flow of a viscoelastic Jeffrey fluid from a permeable isothermal sphere embedded in a porous medium is studied. Thermal radiation flux and heat generation/absorption are also incorporated in the model. A non-Darcy drag force model is employed to simulate the effects of linear porous media drag and second order Forchheimer drag. The Rosseland diffusion algebraic approximation is utilized to simulate thermal radiation effects. The non-dimensionalized boundary layer equations are solved using implicit, finite-difference scheme. The influence of Darcy number (Da, Deborah number (De, ratio of relaxation to retardation times (λ, radiation parameter (F, Forchheimer inertial parameter (Λ and heat generation/absorption parameter (Δ, on normalized velocity, temperature, concentration, skin friction, heat and mass transfer rates are also studied. The present study has applications in the storage of nuclear waste materials.

  9. Sustainable cold generation by district heat driven absorption refrigerating machinery. High chilling of return flow; Nachhaltige Kaelteerzeugung durch Fernwaermeangetriebene Absorptionskaeltemaschine. Hohe Auskuehlung des Ruecklaufs

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Wolfgang

    2011-06-15

    Cold generation with district heat is still an exception in Germany. The trend towards combined heat and power generation and the increasing demand for reserve power within minutes and at acceptable cost, the economic efficieny of thermal refrigeration processes will be easier to define in the future. The author presents an exemplary building in the German city of Giessen, where a cafe on the 13th level as well as a doctor's surgery are cooled in summer by an absorption refrigerator cooled by district heat.

  10. A simulation study on performance evaluation of single-stage LiBr–H2O vapor absorption heat pump for chip cooling

    Directory of Open Access Journals (Sweden)

    Manu S.

    2016-12-01

    Full Text Available The growth of Lithium Bromide–Water (LiBr–H2O absorption based heat pump is encouraged for the necessity of extracting high heat from the electronic chips. This paper presents a simulation study of single-stage LiBr–H2O vapor absorption heat pump for chip cooling. In this study, a detailed thermodynamic analysis of the single-stage LiBr–H2O vapor absorption heat pump for chip cooling in the nonexistence of solution heat exchanger was performed and a user-friendly graphical user interface (GUI package including visual components was developed by using MATlab (2008b. The influence of chip temperature on COP (Coefficient of Performance, flow rates and conductance was examined by using the developed package. The model is validated by using the values available in the literature and indicates that there is a greater reduction in the absorber load. The influence of chip temperature on the performance and thermal loads of individual components was studied and it was concluded that, COP increases from 0.7145 to 0.8421 with an increase in chip temperature.

  11. Researching of the possibility of using absorption heat exchangers for creating the low return temperature heat supply systems based on CHP generation

    Science.gov (United States)

    Yavorovsky, Y. V.; Malenkov, A. S.; Zhigulina, Y. V.; Romanov, D. O.; Kurzanov, S. Y.

    2017-11-01

    This paper deals with the variant of modernization of the heat point within urban heat supply network in order to create the system of heat and cold supply on its basis, providing the suppliers with heat in cold months and with heat and cold in warm months. However, in cold months in the course of heating system operation, the reverse delivery water temperature is maintained below 40 °C. The analysis of heat and power indicators of the heat and cold supply system under different operating conditions throughout the year was conducted. The possibility to use the existing heat networks for the cold supply needs was estimated. The advantages of the system over the traditional heat supply systems that use Combined Heat and Power (CHP) plant as a heat source as exemplified by heat supply system from CHP with ST-80 turbine were demonstrated.

  12. Volumetric Heat Generation and Consequence Raise in Temperature Due to Absorption of Neutrons from Thermal up to 14.9 MeV Energies

    CERN Document Server

    Massoud, E

    2003-01-01

    In this work, the heat generation rate and the consequence rise in temperature due to absorption of all neutrons from thermal energies (E<0.025) up to 14.9 MeV in water, paraffin wax, ordinary concrete and heavy concrete and heavy concrete as some selected hydrogenous materials are investigated. The neutron flux distributions are calculated by both ANISN-code and three group method in which the fast neutrons are expressed by the removal cross section concept while the other two groups (epithermal and thermal) are treated by the diffusion equation. The heat generation can be calculated from the neutron macroscopic absorption of each material or mixture multiplied by the corresponding neutron fluxes. The rise in temperature is then calculated by using both of the heat generation and the thermal conductivity of the selected materials. Some results are compared with the available experimental and theoretical data and a good agreement is achieved.

  13. Heat Generation/Absorption Effects in a Boundary Layer Stretched Flow of Maxwell Nanofluid: Analytic and Numeric Solutions.

    Directory of Open Access Journals (Sweden)

    Muhammad Awais

    Full Text Available Analysis has been done to investigate the heat generation/absorption effects in a steady flow of non-Newtonian nanofluid over a surface which is stretching linearly in its own plane. An upper convected Maxwell model (UCM has been utilized as the non-Newtonian fluid model in view of the fact that it can predict relaxation time phenomenon which the Newtonian model cannot. Behavior of the relaxations phenomenon has been presented in terms of Deborah number. Transport phenomenon with convective cooling process has been analyzed. Brownian motion "Db" and thermophoresis effects "Dt" occur in the transport equations. The momentum, energy and nanoparticle concentration profiles are examined with respect to the involved rheological parameters namely the Deborah number, source/sink parameter, the Brownian motion parameters, thermophoresis parameter and Biot number. Both numerical and analytic solutions are presented and found in nice agreement. Comparison with the published data is also made to ensure the validity. Stream lines for Maxwell and Newtonian fluid models are presented in the analysis.

  14. Effect of ultrasound and heat on percutaneous absorption of l-ascorbic acid: human in vitro studies on Franz cell and Petri dish systems.

    Science.gov (United States)

    Jung, E C; Zhu, H; Zou, Y; Elmahdy, A; Cao, Y; Hui, X; Maibach, H I

    2016-12-01

    Percutaneous absorption of l-ascorbic acid (LAA) is limited due to its high hydrophilicity and low stability. Here, we investigated the effect of post-dosing sonophoresis (329 kHz, 20 mW cm(-2) ) and heat (36°C) on transdermal delivery of LAA. Ultrasound/heat, heat and control treatments were applied on skin surface for 2 and 5 min after topical application of C14-labelled LAA aqueous solution. After 15 min post-exposure, radioactivity was measured in tape-striped stratum corneum (TS-SC), epidermis, dermis and receptor fluid. As Franz diffusion cell model may have different acoustic response than in vivo human tissues, a novel Petri dish model was developed and compared with Franz cell model on the effects of ultrasound/heat treatment on the skin permeability. Five-min ultrasound/heat treatment significantly accelerated skin absorption/penetration of LAA; 2-min treatment showed no enhancement effect on Franz diffusion cell model at the end of experiment. The use of Petri dish model significantly increased LAA concentrations in epidermis after 5 min of ultrasound/heat treatment, compared to the results of Franz cell model. Combination of ultrasound (329 kHz, 20 mW cm(-2) ) and heat (36°C) significantly enhanced LAA transdermal penetration, when the time of treatment was sufficient (5 min). As Petri dish model was designed to simulate acoustic respond of dense human tissue to ultrasound, the difference between Franz cell and Petri dish models suggests that the enhancement effect of ultrasound/heat on skin penetration in vivo may be greater than that determined on in vitro Franz cell model. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  15. Chemically reacting on MHD boundary layer flow of CuO-water and MgO-water nanofluids past a stretching sheet in porous media with radiation absorption and heat generation/absorption

    Science.gov (United States)

    Kumaresan, E.; Vijaya Kumar, A. G.; Rushi Kumar, B.

    2017-11-01

    In the present investigation, a numerical analysis has been carried out for steady two dimensional MHD free convective boundary layer flows of electrically conducting nanofluids past a uniformly stretching sheet through porous media with radiation absorption, heat generation/absorption, thermal radiation, chemical reaction, thermo-diffusion and diffusion – thermo effects. We considered two types of nanofluids namely MgO-water and CuO-water. The mathematical model was governed by a system of linear and non-linear partial differential equations with prescribed boundary conditions. The governing boundary-layer equations are first transformed into a system of coupled nonlinear ordinary differential equations using similarity variables. The transformed equations were solved numerically by the shooting method with Runge-Kutta scheme. Finally the effects of various dimensionless governing parameters like magnetic field parameter, chemical reaction parameter, thermal radiation parameter, radiation absorption parameter, heat generation parameter, Dufour number, Soret number, volume fraction of the nanoparticles and shape of the nanoparticles on velocity, temperature and concentration profiles along with the friction factor, local Nusselt and Sherwood numbers are thoroughly studied and explicitly explained in tabular form.

  16. Reduction in biomass burning aerosol light absorption upon humidification: Roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

    Energy Technology Data Exchange (ETDEWEB)

    lewis, Kristen A.; Arnott, W. P.; Moosmuller, H.; Chakrabarti, Raj; Carrico, Christian M.; Kreidenweis, Sonia M.; Day, Derek E.; Malm, William C.; Laskin, Alexander; Jimenez, Jose L.; Ulbrich, Ingrid M.; Huffman, John A.; Onasch, Timothy B.; Trimborn, Achim; Liu, Li; Mishchenko, M.

    2009-11-27

    Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used are Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients reveal a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: 1. Shielding of inner monomers after particle consolidation or collapse with water uptake; 2. The contribution of mass transfer through evaporation and condensation at high relative humidity to the usual heat transfer pathway for energy release by laser heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

  17. Effects of thermal radiation and magnetic field on unsteady mixed convection flow and heat transfer over an exponentially stretching surface with suction in the presence of internal heat generation/absorption

    Directory of Open Access Journals (Sweden)

    Elsayed M.A. Elbashbeshy

    2012-10-01

    Full Text Available In this paper, the problem of unsteady laminar two-dimensional boundary layer flow and heat transfer of an incompressible viscous fluid in the presence of thermal radiation, internal heat generation or absorption, and magnetic field over an exponentially stretching surface subjected to suction with an exponential temperature distribution is discussed numerically. The governing boundary layer equations are reduced to a system of ordinary differential equations. New numerical method using Mathematica has been used to solve such system after obtaining the missed initial conditions. Comparison of obtained numerical results is made with previously published results in some special cases, and found to be in a good agreement.

  18. Effects of Thermal Radiation on Mixed Convection Flow of a Micropolar Fluid from an Unsteady Stretching Surface with Viscous Dissipation and Heat Generation/Absorption

    Directory of Open Access Journals (Sweden)

    Khilap Singh

    2016-01-01

    Full Text Available A numerical model is developed to examine the effects of thermal radiation on unsteady mixed convection flow of a viscous dissipating incompressible micropolar fluid adjacent to a heated vertical stretching surface in the presence of the buoyancy force and heat generation/absorption. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The model contains nonlinear coupled partial differential equations which have been converted into ordinary differential equation by using the similarity transformations. The dimensionless governing equations for this investigation are solved by Runge-Kutta-Fehlberg fourth fifth-order method with shooting technique. Numerical solutions are then obtained and investigated in detail for different interesting parameters such as the local skin-friction coefficient, wall couple stress, and Nusselt number as well as other parametric values such as the velocity, angular velocity, and temperature.

  19. Computational study of Jeffrey’s non-Newtonian fluid past a semi-infinite vertical plate with thermal radiation and heat generation/absorption

    Directory of Open Access Journals (Sweden)

    S. Abdul Gaffar

    2017-06-01

    Full Text Available The nonlinear, steady state boundary layer flow, heat and mass transfer of an incompressible non-Newtonian Jeffrey’s fluid past a semi-infinite vertical plate is examined in this article. The transformed conservation equations are solved numerically subject to physically appropriate boundary conditions using a versatile, implicit finite-difference Keller box technique. The influence of a number of emerging non-dimensional parameters, namely Deborah number (De, ratio of relaxation to retardation times (λ, Buoyancy ratio parameter (N, suction/injection parameter (fw, Radiation parameter (F, Prandtl number (Pr, Schmidt number (Sc, heat generation/absorption parameter (Δ and dimensionless tangential coordinate (ξ on velocity, temperature and concentration evolution in the boundary layer regime is examined in detail. Also, the effects of these parameters on surface heat transfer rate, mass transfer rate and local skin friction are investigated. This model finds applications in metallurgical materials processing, chemical engineering flow control, etc.

  20. Evaluation of an Absorption Heat Pump to Mitigate Plant Capacity Reduction Due to Ambient Temperature Rise for an Air-Cooled Ammonia and Water Cycle: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bharathan, D.; Nix, G.

    2001-08-06

    Air-cooled geothermal plants suffer substantial decreases in generating capacity at increased ambient temperatures. As the ambient temperature rises by 50 F above a design value of 50 F, at low brine-resource temperatures, the decrease in generating capacity can be more than 50%. This decrease is caused primarily by increased condenser pressure. Using mixed-working fluids has recently drawn considerable attention for use in power cycles. Such cycles are more readily amenable to use of absorption ''heat pumps.'' For a system that uses ammonia and water as the mixed-working fluid, this paper evaluates using an absorption heat pump to reduce condenser backpressure. At high ambient temperatures, part of the turbine exhaust vapor is absorbed into a circulating mixed stream in an absorber in series with the main condenser. This steam is pumped up to a higher pressure and heated to strip the excess vapor, which is recondensed using an additional air-cooled condenser. The operating conditions are chosen to reconstitute this condensate back to the same concentration as drawn from the original system. We analyzed two power plants of nominal 1-megawatt capacity. The design resource temperatures were 250 F and 300 F. Ambient temperature was allowed to rise from a design value of 50 F to 100 F. The analyses indicate that using an absorption heat pump is feasible. For the 300 F resource, an increased brine flow of 30% resulted in a net power increase of 21%. For the 250 F resource, the increase was smaller. However, these results are highly plant- and equipment-specific because evaluations must be carried out at off-design conditions for the condenser. Such studies should be carried out for specific power plants that suffer most from increased ambient temperatures.

  1. Design and Economic Potential of an Integrated High-Temperature Fuel Cell and Absorption Chiller Combined Cooling, Heat, and Power System

    Science.gov (United States)

    Hosford, Kyle S.

    Clean distributed generation power plants can provide a much needed balance to our energy infrastructure in the future. A high-temperature fuel cell and an absorption chiller can be integrated to create an ideal combined cooling, heat, and power system that is efficient, quiet, fuel flexible, scalable, and environmentally friendly. With few real-world installations of this type, research remains to identify the best integration and operating strategy and to evaluate the economic viability and market potential of this system. This thesis informs and documents the design of a high-temperature fuel cell and absorption chiller demonstration system at a generic office building on the University of California, Irvine (UCI) campus. This work details the extension of prior theoretical work to a financially-viable power purchase agreement (PPA) with regard to system design, equipment sizing, and operating strategy. This work also addresses the metering and monitoring for the system showcase and research and details the development of a MATLAB code to evaluate the economics associated with different equipment selections, building loads, and economic parameters. The series configuration of a high-temperature fuel cell, heat recovery unit, and absorption chiller with chiller exhaust recirculation was identified as the optimal system design for the installation in terms of efficiency, controls, ducting, and cost. The initial economic results show that high-temperature fuel cell and absorption chiller systems are already economically competitive with utility-purchased generation, and a brief case study of a southern California hospital shows that the systems are scalable and viable for larger stationary power applications.

  2. Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

    Directory of Open Access Journals (Sweden)

    L. Liu

    2009-11-01

    Full Text Available Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used were Montana ponderosa pine (Pinus ponderosa, southern California chamise (Adenostoma fasciculatum, and Florida saw palmetto (Serenoa repens. Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients revealed a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: (1 shielding of inner monomers after particle consolidation or collapse with water uptake; (2 the lower case contribution of mass transfer through evaporation and condensation at high relative humidity (RH to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

  3. Reduction in biomass burning aerosol light absorption upon humidification: roles of inorganically-induced hygroscopicity, particle collapse, and photoacoustic heat and mass transfer

    Science.gov (United States)

    Lewis, K. A.; Arnott, W. P.; Moosmüller, H.; Chakrabarty, R. K.; Carrico, C. M.; Kreidenweis, S. M.; Day, D. E.; Malm, W. C.; Laskin, A.; Jimenez, J. L.; Ulbrich, I. M.; Huffman, J. A.; Onasch, T. B.; Trimborn, A.; Liu, L.; Mishchenko, M. I.

    2009-11-01

    Smoke particle emissions from the combustion of biomass fuels typical for the western and southeastern United States were studied and compared under high humidity and ambient conditions in the laboratory. The fuels used were Montana ponderosa pine (Pinus ponderosa), southern California chamise (Adenostoma fasciculatum), and Florida saw palmetto (Serenoa repens). Information on the non-refractory chemical composition of biomass burning aerosol from each fuel was obtained with an aerosol mass spectrometer and through estimation of the black carbon concentration from light absorption measurements at 870 nm. Changes in the optical and physical particle properties under high humidity conditions were observed for hygroscopic smoke particles containing substantial inorganic mass fractions that were emitted from combustion of chamise and palmetto fuels. Light scattering cross sections increased under high humidity for these particles, consistent with the hygroscopic growth measured for 100 nm particles in HTDMA measurements. Photoacoustic measurements of aerosol light absorption coefficients revealed a 20% reduction with increasing relative humidity, contrary to the expectation of light absorption enhancement by the liquid coating taken up by hygroscopic particles. This reduction is hypothesized to arise from two mechanisms: (1) shielding of inner monomers after particle consolidation or collapse with water uptake; (2) the lower case contribution of mass transfer through evaporation and condensation at high relative humidity (RH) to the usual heat transfer pathway for energy release by laser-heated particles in the photoacoustic measurement of aerosol light absorption. The mass transfer contribution is used to evaluate the fraction of aerosol surface covered with liquid water solution as a function of RH.

  4. Complete β -decay pattern for the high-priority decay-heat isotopes 137I and 137Xe determined using total absorption spectroscopy

    Science.gov (United States)

    Rasco, B. C.; Rykaczewski, K. P.; Fijałkowska, A.; Karny, M.; Wolińska-Cichocka, M.; Grzywacz, R. K.; Gross, C. J.; Stracener, D. W.; Zganjar, E. F.; Blackmon, J. C.; Brewer, N. T.; Goetz, K. C.; Johnson, J. W.; Jost, C. U.; Hamilton, J. H.; Miernik, K.; Madurga, M.; Miller, D.; Padgett, S.; Paulauskas, S. V.; Ramayya, A. V.; Spejewski, E. H.

    2017-05-01

    Background: An assessment done under the auspices of the Nuclear Energy Agency in 2007 suggested that the β decays of abundant fission products in nuclear reactors may be incomplete. Many of the nuclei are potentially affected by the so called pandemonium effect and their β -γ decay heat should be restudied using the total absorption technique. The fission products 137I and 137Xe were assigned highest priority for restudy due to their large cumulative fission branching fractions. In addition, measuring β -delayed neutron emission probabilities is challenging and any new technique for measuring the β -neutron spectrum and the β -delayed neutron emission probabilities is an important addition to nuclear physics experimental techniques. Purpose: To obtain the complete β -decay pattern of 137I and 137Xe and determine their consequences for reactor decay heat and ν¯e emission. Complete β -decay feeding includes ground state to ground state β feeding with no associated γ rays, ground state to excited states β transitions followed by γ transitions to the daughter nucleus ground state, and β -delayed neutron emission from the daughter nucleus in the case of 137I. Method: We measured the complete β -decay intensities of 137I and 137Xe with the Modular Total Absorption Spectrometer at Oak Ridge National Laboratory. We describe a technique for measuring the β -delayed neutron energy spectrum, which also provides a measurement of the β -neutron branching ratio, Pn. Results: We validate the current Evaluated Nuclear Structure Data File (ENSDF) evaluation of 137Xeβ decay. We find that major changes to the current ENSDF assessment of 137Iβ -decay intensity are required. The average γ energy per β decay for 137Iβ decay (γ decay heat) increases by 19%, from 1050-1250 keV, which increases the average γ energy per 235U fission by 0.11 % . We measure a β -delayed neutron branching fraction for 137Iβ decay of 7.9 ±0.2 (fit )±0.4 (sys )% and we provide a

  5. Thermodynamics of heat and Mass Transfer in Chemical Engineering. Vol. 2. Application of Rectification, Adsorption, Absorption and Extraction. Die Thermodynamik des Waerme- und Stoffaustausches in der Verfahrenstechnik. Bd. 2. Anwendung auf Rektifikation, Adsorption, Absorption und Extraktion

    Energy Technology Data Exchange (ETDEWEB)

    Matz, W.

    1980-01-01

    The approved textbook with the title: Thermodynamics of Heat and Mass Transfer in Chemical Engineering is in its 2nd revised edition turned again towards to students of technical and natural science, as well as towards professionals and researchers that are confronted with thermodynamical problems of chemical engineering. The worked out foundations of volume one are here applied to the fields of rectification adsorption from the gaseous phase, absorption and extraction. After a treatment of the especially important equilibrium follow considerations on thermal and mass transfer and kinetics. In the parts of industrial applications and in many examples on many-component systems it is shown that these thermal separation techiques draw their importance not only from purification and separation of substances but also by an important support of environmental protection.

  6. Design and Economic Analysis of a Heating/Absorption Cooling System Operating with Municipal Solid Waste Digester: A Case Study of Gazi University

    Science.gov (United States)

    Coşar, Gökhan; Pooyanfar, Mirparham; Amirabedin, Ehsan; Topal, Hüseyin

    2013-12-01

    Recovering energy from municipal solid waste (MSW) is one of the most important issues of energy management in developed countries. This raises even more interest as world fossil fuel reserves diminish and fuel prices rise. Being one of main processes of waste disposal, anaerobic digestion can be used as a means to reduce fossil fuel and electricity consumption as well as reducing emissions. With growing demand for cooling in Turkey, especially during warm seasons and considering the energy costs, utilizing heat-driven absorption cooling systems coupled with an anaerobic digester for local cooling purposes is a potentially interesting alternative for electricity driven compression cooling. The aim of this article is to study the viability of utilizing biogas obtained from MSW anaerobic digestion as the main fuel for heating facilities of Gazi University, Turkey and also the energy source for an absorption cooling system designed for the central library of the aforementioned campus. The results prove that the suggested system is sustainably and financially appealing and has the potential to replace the conventional electricity driven cooling systems with a reasonable net present worth; moreover, it can notably reduce carbon dioxide emissions.

  7. Influence of thermal radiation and heat generation/absorption on MHD heat transfer flow of a micropolar fluid past a wedge considering hall and ion slip currents

    Directory of Open Access Journals (Sweden)

    Uddin Ziya

    2014-01-01

    Full Text Available In this paper a numerical model is developed to examine the effect of thermal radiation on magnetohydrodynamic heat transfer flow of a micropolar fluid past a non-conducting wedge in presence of heat source/sink. In the model it is assumed that the fluid is viscous, incompressible and electrically conducting. The Hall and ion slip effects have also been taken into consideration. The model contains highly non-linear coupled partial differential equations which have been converted into ordinary differential equation by using the similarity transformations. These equations are then solved numerically by Shooting technique along with the Runge-Kutta-Fehlberg integration scheme for entire range of parameters with appropriate boundary conditions. The effects of various parameters involved in the problem have been studied with the help of graphs. Numerical values of skin friction coefficients and Nusselt number are presented in tabular form. The results showed that the micropolar fluids are better to reduce local skin drag as compared to Newtonian fluids and the presence of heat sink increases the heat transfer rate.

  8. In-vivo pilot study on physical absorption enhancement of active skin whitening ingredients by heat and ultrasound

    NARCIS (Netherlands)

    Scheja, M.M.; Wang, X.; Ma, P.

    2012-01-01

    In Q3 of 2011, Philips Research received a brief from the Skin Carecategory of the Philips Consumer Lifestyle sector to explore the feasibility of heat and ultrasound to increase skin uptake of active skin whitening ingredients from cosmetics. Philips Research Asia-Shanghai performed an in-vivo

  9. Mixed convection stagnation-point flow of nanofluids over a stretching/shrinking sheet in a porous medium with internal heat generation/absorption

    Directory of Open Access Journals (Sweden)

    Dulal Pal

    2015-05-01

    Full Text Available In this paper, we analyzed the buoyancy-driven radiative non-isothermal heat transfer in a nanofluid stagnation-point flow over a stretching/shrinking sheet embedded in a porous medium.The effects of thermal radiation and internal heat generation/absorption along with suction/injection at the boundary are also considered. Three different types of nanofluids, namely the Copper-water, the Alumina-water and the Titanium dioxide water are considered. The resulting coupled nonlinear differential equations are solved numerically by a fifth-order Runge-Kutta-Fehlberg integration scheme with a shooting technique. A good agreement is found between the present numerical results and the available results in the literature for some special cases. The effects of the physical parameters on the flow and temperature characteristics are presented through tables and graphs, and the salient features are discussed. The results obtained reveal many interesting behaviors that warrant further study on the heat transfer enhancement due to the nanofluids.

  10. Channeling of high-power radio waves under conditions of strong anomalous absorption in the presence of an averaged electron heating source

    Science.gov (United States)

    Vas'kov, V. V.; Ryabova, N. A.

    2010-02-01

    Strong anomalous absorption of a high-power radio wave by small-scale plasma inhomogeneities in the Earth’s ionosphere can lead to the formation of self-consistent channels (solitons) in which the wave propagates along the magnetic field, but has a soliton-like intensity distribution across the field. The structure of a cylindrical soliton as a function of the wave intensity at the soliton axis is analyzed. Averaged density perturbations leading to wave focusing were calculated using the model proposed earlier by Vas’kov and Gurevich (Geomagn. Aéron. 16, 1112 (1976)), in which an averaged electron heating source was used. It is shown that, under conditions of strong electron recombination, the radii of individual solitons do not exceed 650 m.

  11. Heat

    CERN Document Server

    Lawrence, Ellen

    2016-01-01

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

  12. Theoretical investigation of the doubly stratified flow of an Eyring-Powell nanomaterial via heat generation/absorption

    Science.gov (United States)

    Khan, M. Ijaz; Waqas, M.; Alsaedi, A.; Hayat, T.; Khan, M. Imran

    2017-11-01

    The mixed convective flow of an Eyring-Powell nanomaterial in a doubly stratified medium is addressed in this paper. The stretching surface has varying thickness. The nanofluid model given by Buongiorno is utilized in the formulation of energy and concentration expressions. Heat generation is also retained. Ordinary differential systems are obtained by utilizing the transformations procedure. Homotopy series solutions containing exponentially functions are developed. Significant characteristics of influential variables for velocity, temperature, nanoparticle concentration, skin friction coefficient and Nusselt and Sherwood numbers are reported through graphs and tables. It is found that stratification phenomenon leads to a decay in temperature and nanoparticle concentration.

  13. Numerical study of the heat and material transport in the absorption of water vapour in aqueous LiBr solution; Numerische Untersuchung des Waerme- und Stofftransports bei der Absorption von Wasserdampf in waessriger LiBr-Loesung

    Energy Technology Data Exchange (ETDEWEB)

    Olbricht, Michael; Buchholz, Niklas; Fries, Simon; Addy, Joseph; Luke, Andrea [Kassel Univ. (Germany). Fachgebiet Technische Thermodynamik

    2016-07-01

    In absorption refrigerating machines with the working-material pair water/lithium bromide usually falling-film apparatuses are applied as absorbers, evaporators, and condensers. These are often performed as horizontal tube bundes. As critical, the process limiting component in the literature the absorper is called, because of which the their running, coupled heat and material transport processes are more detailedly theoretically studied. For this a model was developed, which maps starting from analytically describable physical connections the transport processes in the apparatus. The flow in the tube bundle is hereby divided in two sections, the flow in the liquid film on the tubes and the drop fall between the tubes. The basic equations are numerically solved under given boundary conditions, whereby for the description of the drop fall phase addititonally semi-empirical calculation approaches are used. The results are elucidated by means of concentration and temperature profiles in the film. A distinctly faster formation of the temperature boundary layer than the concentration boundary layer in the fim is shown, which makes the material transport to the limiting transport process in the absorber, which is already known from experimental studies.The physical plausibility of the model is by means of this fact confirmed by an analysis of the coupled transport processes by means of dimensionless characteristic numbers. Furthermore from the results an improvement of the heat and material transport at diminishing of the tube diameter can be derived. Just so by the results of the study an estimation method for the quality of the absorber by means of the subcooling is shown.

  14. Thermodynamic analysis of a novel compact power generation and waste heat operated absorption, ejector-jet pump refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Anil; Kumar, Raj [YMCA University of Science and Technology, Faridabad (India)

    2014-09-15

    An R-152a ejector-jet pump refrigeration cycle and a LiBr-H{sub 2}O absorption refrigeration cycle have been integrated with a renewable energy power generator for making a proposed 'novel compact cogeneration cycle'. The exergy analysis of this proposed cycle leads to a possible performance improvement. Nearly 71.12% of the input exergy is destructed due to irreversibilities in the different components. The useful exergy output is around 7.12%. The exhaust exergy lost to the environment is 21.76%, which is lower than the exhaust energy lost 37.6% of the input energy, while the useful energy output is approximately 19.3%. The refrigerants used and the exhaust gas emissions samples are found to be favourable for reducing the global environmental related problems. The results also show that the coupling of the entrainment ratios of the ejector and jet pump has great effect on the exergy and energy efficiency.

  15. Viscous Dissipation and Thermal Radiation effects in MHD flow of Jeffrey Nanofluid through Impermeable Surface with Heat Generation/Absorption

    Science.gov (United States)

    Sharma, Kalpna; Gupta, Sumit

    2017-06-01

    This paper investigates steady two dimensional flow of an incompressible magnetohydrodynamic (MHD) boundary layer flow and heat transfer of nanofluid over an impermeable surface in presence of thermal radiation and viscous dissipation. By using similarity transformation, the arising governing equations of momentum, energy and nanoparticle concentration are transformed into coupled nonlinear ordinary differential equations, which are than solved by homotopy analysis method (HAM). The effect of different physical parameters, namely, Prandtl number Pr, Eckert number Ec, Magnetic parameter M, Brownian motion parameter Nb, Thermophoresis parameter Nt, Lewis parameter Le and Radiation parameter Rd on the velocity, temperature and concentration profiles along with the Nusselt number and skin friction coefficient are discussed graphically and in tabular form in details. The present results are also compared with existing limiting solutions.

  16. The role of natural E-region plasma turbulence in the enhanced absorption of HF radio waves in the auroral ionosphere:Implications for RF heating of the auroral electrojet

    Directory of Open Access Journals (Sweden)

    T. R. Robinson

    1994-03-01

    Full Text Available Physical processes which affect the absorption of radio waves passing through the auroral E-region when Farley-Buneman irregularities are present are examined. In particular, the question of whether or not it is legitimate to include the anomalous wave-enhanced collision frequency, which has been used successfully to account for the heating effects of Farley-Buneman waves in the auroral E-region, in the usual expression for the radio-wave absorption coefficient is addressed. Effects also considered are those due to wave coupling between electromagnetic waves and high-frequency electrostatic waves in the presence of Farley-Buneman irregularities. The implications for radio-wave heating of the auroral electrojet of these processes are also discussed. In particular, a new theoretical model for calculating the effects of high-power radio-wave heating on the electron temperature in an electrojet containing Farley-Buneman turbulence is presented.

  17. Influence of geometrical non-uniformities of LaNi5 metal hydride bed on its structure and heat and mass transfer at hydrogen absorption

    Science.gov (United States)

    Blinov, D. V.; Dunikov, D. O.; Kazakov, A. N.; Romanov, I. A.

    2017-11-01

    We perform cycling of a 500 g bed of La0.9Ce0.1Ni5 intermetallic compound in vertical and horizontal orientations with measurements of PCT isotherms, and further XRD and SEM investigation of bed structure. Significant decrease in equilibrium absorption pressure is observed in vertical orientation of the bed from 1.58 to 1.36 MPa at 333K, and from 2.68 to 2.51 MPa at 353K, accompanied by evident particle segregation by the bed height and densification at a bottom with formation of a robust agglomerate of small particles (mass transfer inside a vertical metal hydride reactor RSP-8 with 1 kg of La0.9Ce0.1Ni5 also show considerable non-uniformity of pressure inside the bed. If the reactor is charged from the top the hydrogen pressure at the bottom is lower on 0.2-0.3 MPa, which results in earlier occurrence of heat and mass transfer crisis.

  18. Fast heating induced impulse halogenation of refractory sample components in electrothermal atomic absorption spectrometry by direct injection of a liquid halogenating agent.

    Science.gov (United States)

    György, Krisztina; Ajtony, Zsolt; Van Meel, Katleen; Van Grieken, René; Czitrovszky, Aladár; Bencs, László

    2011-09-15

    A novel electrothermal atomic absorption spectrometry (ETAAS) method was developed for the halogenation of refractory sample components (Er, Nd and Nb) of lithium niobate (LiNbO(3)) and bismuth tellurite (Bi(2)TeO(5)) optical single crystals to overcome memory effects and carry-over. For this purpose, the cleaning step of a regular graphite furnace heating program was replaced with a halogenation cycle. In this cycle, after the graphite tube cooled to room temperature, a 20 μL aliquot of liquid carbon tetrachloride (CCl(4)) was dispensed with a conventional autosampler into the graphite tube. The CCl(4) was partially dried at 80°C under the mini-flow (40 cm(3) min(-1)) condition of the Ar internal furnace gas (IFG), then the residue was decomposed (pyrolyzed) by fast furnace heating at 1900-2100°C under interrupted flow of the IFG. This step was followed by a clean-out stage at 2100°C under the maximum flow of the IFG. The advantage of the present method is that it does not require any alteration to the graphite furnace gas supply system in contrast to most of the formerly introduced halogenation techniques. The effectiveness of the halogenation method was verified with the determination of Er and Nd dopants in the optical crystals. In these analyses, a sensitivity decrease was observed, which was likely due to the enhanced deterioration of the graphite tube surface. Therefore, the application of mathematical correction (resloping) of the calibration was also required. The calibration curves were linear up to 1.5 and 10 μmol L(-1) for Er and Nd, respectively. Characteristic masses of 18 and 241 pg and the limit of detection (LOD) values of 0.017 and 0.27 μmol L(-1) were found for Er and Nd, respectively. These LOD data correspond to 0.68 μmol mol(-1) Er and 11 μmol mol(-1) Nd in solid bismuth tellurite samples. The analytical results were compared with those obtained by a conventional ETAAS method and validated with X-ray fluorescence spectrometry analysis

  19. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI); Marsala, Joseph (Glen Ellyn, IL)

    1994-11-29

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium.

  20. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, B.A.; Zawacki, T.S.; Marsala, J.

    1994-11-29

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium. 13 figures.

  1. Présentation d'une boucle prototype de pompe à chaleur à absorption haute température industrielle de 100 kW Description of a 100-Kw Prototype Loop for an Industrial High-Temperature Absorption Heat-Pump

    Directory of Open Access Journals (Sweden)

    Thomas D.

    2006-11-01

    Full Text Available II apparait indispensable, dans le contexte énergétique actuel, de mettre au point de nouvelles techniques de revalorisation d'énergie. Les pompes à chaleur à absorption peuvent, dans certains secteurs industriels, apporter des solutions particulièrement intéressantes par rapport aux pompes à chaleur à compression notamment, en particulier dans le domaine des hautes températures de revalorisation (120-150 °C. Pour mener à bien les études entreprises sur ce thème, le Gaz de France travaille en étroite collaboration avec l'Institut du Génie Chimique de Toulouse et la Société Creusot-Loire. Dans une première partie, les auteurs rappellent les principes de fonctionnement des pompes à chaleurs à absorption et leurs caractères spécifiques. Quelques exemples d'applications industrielles sont proposés. Ils présentent, dans une deuxième partie, la boucle prototype de 100 kW qui a été réalisée et décrivent ses caractéristiques, son cycle de fonctionnement et le programme des essais. Ce pilote de taille semi-industrielle utilise le couple eau-bromure de lithium. La définition d'un prototype industriel de pompe à chaleur à absorption haute température et les compléments de recherche entrepris dans ce domaine constituent la troisième partie de la communication. In the present energy context, it seems absolutely necessary to develop new techniques for energy upgrading. In some industrial sectors, absorption heat pumps may bring particularly interesting solutions compared, in particular, to compression heat pumps, especially in the field of high-temperature upgrading (120-150°C. Reasearch is being done in this field by Gaz de France in close collaboration with the Institut du Génie Chimique in Toulouse and with Creusot-Loire. ,The first part of this article reviews the operating principles of absorption heat pumps and their specific features. Some examples of industrial applications are then proposed. The second part

  2. Heat-epimerized tea catechins rich in gallocatechin gallate and catechin gallate are more effective to inhibit cholesterol absorption than tea catechins rich in epigallocatechin gallate and epicatechin gallate.

    Science.gov (United States)

    Ikeda, Ikuo; Kobayashi, Makoto; Hamada, Tadateru; Tsuda, Koichi; Goto, Hitomi; Imaizumi, Katsumi; Nozawa, Ayumu; Sugimoto, Akio; Kakuda, Takami

    2003-12-03

    It has been known that tea catechins, (-)-epicatechin (1), (-)-epigallocatechin (2), (-)-epicatechin gallate (3), and (-)-epigallocatechin gallate (4) are epimerized to(-)-catechin (5), (-)-gallocatechin (6), (-)-catechin gallate (7), and (-)-gallocatechin gallate (8), respectively, during retort pasteurization. We previously reported that tea catechins, mainly composed of 3 and 4, effectively inhibit cholesterol absorption in rats. In this study, the effect of heat-epimerized catechins on cholesterol absorption was compared with tea catechins. Both tea catechins and heat-epimerized catechins lowered lymphatic recovery of cholesterol in rats cannulated in the thoracic duct and epimerized catechins were more effective than tea catechins. The effect of purified catechins on micellar solubility of cholesterol was examined in an in vitro study. The addition of gallate esters of catechins reduced micellar solubility of cholesterol by precipitating cholesterol from bile salt micelles. Compounds 7 and 8 were more effective to precipitate cholesterol than 3 and 4, respectively. These observations strongly suggest that heat-epimerized catechins may be more hypocholesterolemic than tea catechins.

  3. Absorption spectra measurements of the x-ray radiation heated sio{sub 2} aerogel plasma in 'dog-bone' targets irradiated by high power laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y; Dong, Q-L; Wang, S-J; Li, Y-T; Zhang, J [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Wei, H-G; Shi, J-R; Zhao, G [National Astronomical Observatories of China, Chinese Academy of Sciences. Beijing 100012 (China); Zhang, J-Y; Wen, T-S; Zhang, W-H; Hu, X; Liu, S-Y; Ding, Y-K; Zhang, L; Tang, Y-J; Zhang, B-H; Zheng, Z-J [Research Center for Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Nishimura, H; Fujioka, S [Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan)], E-mail: yizhang@aphy.iphy.ac.cn, E-mail: ytli@aphy.iphy.ac.cn, E-mail: jzhang@aphy.iphy.ac.cn (and others)

    2008-05-01

    We studied the opacity effect of the SiO{sub 2} aerogel plasma heated by x-ray radiation produced by high power laser pulses irradiating the inner surface of golden 'dog-bone' targets. The PET crystal spectrometer was used to measure the absorption spectra of the plasmas in the range from 6.4 A to 7.4 A, among which the line emissions involving the K shell of Si ions from He-like to neutral atom were located. The experimental results were analyzed with Detailed-Level-Accounting method. As the plasma temperature increased, the characteristic lines of highly ionized ions gradually dominated the absorption spectrum.

  4. Simulation of an absorption cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Egrican, N. (Istanbul Technical Univ. (TR). Dept. of Mechanical Engineering); Yigit, A. (Uludag Univ., Bursa (TR). Faculty of Engineering)

    1992-06-01

    We describe a finite difference solution for combined heat and mass transfer on vapor absorption into a laminar liquid film. Heat- and mass-transfer coefficients are determined by calculating temperature and concentration variations at the film. A modular computer program has been developed for absorption systems to simulate various cycle configurations. The influence of component temperatures and heat-exchanger effectiveness on cooling coefficients of performance and component heat-transfer rates has been investigated to define optimum operating conditions. (author).

  5. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    Based on a nonlinear mathematical programming model, the sizes and operating conditions of the process units of single-effect absorption refrigeration systems operating with a LiBr–H2O solution are optimized for a specified cooling capacity by minimizing three single objective functions: the tota...

  6. High-efficiency absorption-type heat pumps and refrigerators. From topology to the pilot plant; Hocheffiziente Absorptionsmaschinen zur Versorgung mit Kaelte und Waerme. Von der Topologie zur Pilotanlage

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, F.; Demmel, S.; Lamp, P. [Bayerisches Zentrum fuer Angewandte Energieforschung e.V. (ZAE Bayern), Wuerzburg (Germany); Kahn, R. [Technische Univ. Muenchen (Germany). Physik Dept. E19; Alefeld, G.

    1998-12-31

    Absorption-type heat pumps or refrigerators are systems operated with heat. They have been known for a long time and are frequently used especially in airconditioning in the USA and south-east Asia. However, the conventional technique used is subject to many physical limitations, restricting their broader use. The paper demonstrates ways of overcoming these restrictions, for instance by multi-stage design. The exploitation of topological principles much facilitates the synthesis of novel circuits. The technical relevance of such developments is demonstrated by means of selected examples of executed laboratory and pilot plants. Modern absorption technology saves resources and prevents environmental pollution by consuming less fossil energy compared with the conventional technique, for instance by harnessing the thermal potential of solar energy or utilizing waste heat and residual heat, and, not least, thanks to the use of natural refrigerants. (orig.) [Deutsch] Absorptionswaermepumpen oder -kaeltemaschinen sind durch Waerme angetriebene Anlagen, die seit langem bekannt sind und besonders in der Klimatechnik in den USA und im suedostasiatischen Raum haeufig eingesetzt werden. Die dabei verwendete konventionelle Technik unterliegt allerdings vielfaeltigen physikalischen Einschraenkungen, die ihre noch breitere Anwendung verhindern. Es wird gezeigt, wie diese Einschraenkungen beispielsweise durch Mehrstufigkeit ueberwunden werden koennen. Durch die Verwendung topologischer Grundsaetze wird die Synthese neuartiger Kreislaeufe stark vereinfacht. Die technische Bedeutung solcher Entwicklungen wird an ausgewaehlten Beispielen ausgefuehrter Labor- und Pilotanlagen gezeigt. Durch den im Vergleich zu konventioneller Technik geringeren Verbrauch an fossiler Energie, beispielsweise durch die thermische Nutzung von Sonnenenergie oder durch die Nutzung von Ab- oder Restwaerme und nicht zuletzt durch die Verwendung natuerlicher Kaeltemittel werden bei Einsatz moderner

  7. Open-cycle absorption solar cooling. Part 1: Combined heat and mass transfer on an open flow liquid absorbent solar collector/regenerator

    Science.gov (United States)

    Novak, K. S.; Wood, B. D.; Nelson, D. J.

    1986-05-01

    Previous collector/regenerator models have relied on established heat transfer correlations and the heat and mass transfer analogy to specify heat and mass transfer coefficients. These correlations were derived from relatively simple experiments and do not account for the complexities inherent in the collector/regenerator heat and mass transfer problem. This research was prompted by the need for a more accurate performance model based on experimentally determined combined heat and mass transfer correlations. Experimental data were taken on a prototype (11 x 11 m) collector/regenerator during the summer of 1984 in Tempe, Arizona. The data taken included local solution temperature measurements on the collector but only inlet and exit concentration measurements. A solution energy balance was solved iteratively to determine local concentrations and local heat and mass transfer coefficients. A new collector/regenerator model, based on the derived correlations, accurately predicted actual experimental temperature and concentration data. The model was used to test the effects of various climatic, operational, and collector design variables on evaporation rate.

  8. Enhanced absorption cycle computer model

    Science.gov (United States)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  9. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. No...

  10. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    Science.gov (United States)

    Alquaity, Awad B. S.; KC, Utsav; Popov, Alber; Farooq, Aamir

    2017-12-01

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm-1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10-5 cm-1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  11. Detection of shock-heated hydrogen peroxide (H2O2) by off-axis cavity-enhanced absorption spectroscopy (OA-CEAS)

    KAUST Repository

    Alquaity, Awad

    2017-11-11

    Cavity-enhanced absorption spectroscopy (CEAS) is a promising technique for studying chemical reactions due to its desirable characteristics of high sensitivity and fast time-response by virtue of the increased path length and relatively short photon residence time inside the cavity. Off-axis CEAS (OA-CEAS) is particularly suited for the shock tube applications as it is insensitive to slight misalignments, and cavity noise is suppressed due to non-overlapping multiple reflections of the probe beam inside the cavity. Here, OA-CEAS is demonstrated in the mid-IR region at 1310.068 cm−1 to monitor trace concentrations of hydrogen peroxide (H2O2). This particular probe frequency was chosen to minimize interference from other species prevalent in combustion systems and in the atmosphere. The noise-equivalent detection limit is found to be 3.25 × 10−5 cm−1, and the gain factor of the cavity is 131. This corresponds to a detection limit of 74 ppm of H2O2 at typical high-temperature combustion conditions (1200 K and 1 atm) and 12 ppm of H2O2 at ambient conditions (296 K and 1 atm). To our knowledge, this is the first successful application of the OA-CEAS technique to detect H2O2 which is vital species in combustion and atmospheric science.

  12. Rapid freeze-drying cycle optimization using computer programs developed based on heat and mass transfer models and facilitated by tunable diode laser absorption spectroscopy (TDLAS).

    Science.gov (United States)

    Kuu, Wei Y; Nail, Steven L

    2009-09-01

    Computer programs in FORTRAN were developed to rapidly determine the optimal shelf temperature, T(f), and chamber pressure, P(c), to achieve the shortest primary drying time. The constraint for the optimization is to ensure that the product temperature profile, T(b), is below the target temperature, T(target). Five percent mannitol was chosen as the model formulation. After obtaining the optimal sets of T(f) and P(c), each cycle was assigned with a cycle rank number in terms of the length of drying time. Further optimization was achieved by dividing the drying time into a series of ramping steps for T(f), in a cascading manner (termed the cascading T(f) cycle), to further shorten the cycle time. For the purpose of demonstrating the validity of the optimized T(f) and P(c), four cycles with different predicted lengths of drying time, along with the cascading T(f) cycle, were chosen for experimental cycle runs. Tunable diode laser absorption spectroscopy (TDLAS) was used to continuously measure the sublimation rate. As predicted, maximum product temperatures were controlled slightly below the target temperature of -25 degrees C, and the cascading T(f)-ramping cycle is the most efficient cycle design. In addition, the experimental cycle rank order closely matches with that determined by modeling.

  13. Similarity Analysis for Effects of Variable Diffusivity and Heat Generation/Absorption on Heat and Mass Transfer for a MHD Stagnation-Point Flow of a Convective Viscoelastic Fluid over a Stretching Sheet with a Slip Velocity

    Directory of Open Access Journals (Sweden)

    H. M. El-Hawary

    2013-01-01

    Full Text Available A mathematical analysis has been carried out for stagnation-point heat and mass transfer of a viscoelastic fluid over a stretching sheet with surface slip velocity, concentration dependent diffusivity, thermal convective boundary conditions, and heat source/sink. The governing partial differential equations are reduced to a system of nonlinear ordinary differential equations using Lie group analysis. Numerical solutions of the resulting ordinary differential equations are obtained using shooting method. The influences of various parameters on velocity, temperature, and mass profiles have been studied. Also, the effects of various parameters on the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are given in graphics form and discussed.

  14. Rapid determination of vial heat transfer parameters using tunable diode laser absorption spectroscopy (TDLAS) in response to step-changes in pressure set-point during freeze-drying.

    Science.gov (United States)

    Kuu, Wei Y; Nail, Steven L; Sacha, Gregory

    2009-03-01

    The purpose of this study was to perform a rapid determination of vial heat transfer parameters, that is, the contact parameter K(cs) and the separation distance l(v), using the sublimation rate profiles measured by tunable diode laser absorption spectroscopy (TDLAS). In this study, each size of vial was filled with pure water followed by a freeze-drying cycle using a LyoStar II dryer (FTS Systems) with step-changes of the chamber pressure set-point at to 25, 50, 100, 200, 300, and 400 mTorr. K(cs) was independently determined by nonlinear parameter estimation using the sublimation rates measured at the pressure set-point of 25 mTorr. After obtaining K(cs), the l(v) value for each vial size was determined by nonlinear parameter estimation using the pooled sublimation rate profiles obtained at 25 to 400 mTorr. The vial heat transfer coefficient K(v), as a function of the chamber pressure, was readily calculated, using the obtained K(cs) and l(v) values. It is interesting to note the significant difference in K(v) of two similar types of 10 mL Schott tubing vials, primary due to the geometry of the vial-bottom, as demonstrated by the images of the contact areas of the vial-bottom. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

  15. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, B.A.; Zawacki, T.S.

    1996-12-03

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium. A combination of weak and rich liquor working solution is used as the heat transfer medium. 7 figs.

  16. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

    1996-12-03

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium. A combination of weak and rich liquor working solution is used as the heat transfer medium.

  17. Electric field triggering the spin reorientation and controlling the absorption and release of heat in the induced multiferroic compound EuTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Ranke, P. J. von, E-mail: von.ranke@uol.com.br; Ribeiro, P. O.; Alho, B. P.; Alvarenga, T. S. T.; Nobrega, E. P.; Caldas, A.; Sousa, V. S. R. de; Lopes, P. H. O.; Oliveira, N. A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro–UERJ, Rua São, Francisco Xavier, 524, 20550-013 Rio de Janeiro, Rio de Janerio (Brazil); Gama, S. [Departamento de Ciências Exatas e da Terra-UNIFESP, Diadema, 09971-270 Sao Paulo (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, Sao Paulo (Brazil)

    2015-12-28

    We report remarkable results due to the coupling between the magnetization and the electric field induced polarization in EuTiO{sub 3}. Using a microscopic model Hamiltonian to describe the three coupled sublattices, Eu-(spin-up), Eu-(spin-down), and Ti-(moment), the spin flop and spin reorientation phase transitions were described with and without the electric-magnetic coupling interaction. The external electric field can be used to tune the temperature of the spin reorientation phase transition T{sub SR} = T{sub SR}(E). When the T{sub SR} is tuned around the EuTiO{sub 3}—Néel temperature (T{sub N} = 5.5 K), an outstanding effect emerges in which EuTiO{sub 3} releases heat under magnetic field change. The electric field controlling the spin reorientation transition and the endo-exothermic processes are discussed through the microscopic interactions model parameters.

  18. Worldwide survey of absorption fluids data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S.

    1988-01-01

    The overall objective of this study is to develop improved data for the thermodynamic, transport and physical properties of absorption fluids. A specific objective of this phase of the study is to compile, catalog and coarse-screen the available worldwide data of known absorption fluid systems and publish it as a reference document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. 3 refs., 3 figs., 1 tab.

  19. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  20. Champagne Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    2004-01-01

    The term champagne heat pump denotes a developmental heat pump that exploits a cycle of absorption and desorption of carbon dioxide in an alcohol or other organic liquid. Whereas most heat pumps in common use in the United States are energized by mechanical compression, the champagne heat pump is energized by heating. The concept of heat pumps based on other absorption cycles energized by heat has been understood for years, but some of these heat pumps are outlawed in many areas because of the potential hazards posed by leakage of working fluids. For example, in the case of the water/ammonia cycle, there are potential hazards of toxicity and flammability. The organic-liquid/carbon dioxide absorption/desorption cycle of the champagne heat pump is similar to the water/ammonia cycle, but carbon dioxide is nontoxic and environmentally benign, and one can choose an alcohol or other organic liquid that is also relatively nontoxic and environmentally benign. Two candidate nonalcohol organic liquids are isobutyl acetate and amyl acetate. Although alcohols and many other organic liquids are flammable, they present little or no flammability hazard in the champagne heat pump because only the nonflammable carbon dioxide component of the refrigerant mixture is circulated to the evaporator and condenser heat exchangers, which are the only components of the heat pump in direct contact with air in habitable spaces.

  1. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

    1998-07-21

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration.

  2. Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, B.A.; Zawacki, T.S.

    1998-07-21

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration. 5 figs.

  3. Falling Liquid Films in Absorption Machines

    Science.gov (United States)

    Fujita, Toshihiko

    The absorption machines of the lithium bromide-water type have recently been established as heat source equipments for residential and industrial use, which include refrigerating machines, heat pumps, and heat transformers. Several advanced cycle machines have also been proposed and tested. All of the absorption machines consist fundamentally of four kinds of heat exchangers, i.e. evaporator, absorber, generator, and condenser. The horizontal or vertical falling film system is usually applied to these heat exchangers, since the pressure drop which causes an undesirable change in the fluid temperature is relatively small in either system. The horizontal system is popular for the present, while the vertical system is going to be developed promisingly. This may save an installation space and also fit a plan for the Lorentz cycle. The purpose of this paper is to survey the available information for increasing heat and mass transfer rates in the heat exchangers of absorption machines. Emphasis is placed on the hydrodynamic characteristics of falling liquid films in absorbers and generators. The following topics are covered in this paper: 1. Characteristics of thin liquid films over horizontal tubes 2. Characteristics of wavy thin liquid films flowing down the vertical or inclined wall surface 3. Effect of the artificial surface roughness on the heat and mass transfer rates 4. Enhancement in the heat and mass transfer rates by the Marangoni convection 5. Conditions of film breakdown and the minimum wetting rates.

  4. Enhanced absorption cycle computer model. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, G.; Wilk, M. [Technion-Israel Inst. of Tech., Haifa (Israel). Faculty of Mechanical Engineering

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperatures boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorptions systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system`s components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H{sub 2}O triple-effect cycles, LiCl-H{sub 2}O solar-powered open absorption cycles, and NH{sub 3}-H{sub 2}O single-effect and generator-absorber heat exchange cycles. An appendix contains the User`s Manual.

  5. The Effects of Viscosity and Radiation Absorption on Double ...

    African Journals Online (AJOL)

    This study is devoted to the problem of the effect of radiation absorption on the onset of thermosolutal convection in a horizontal fluid layer taking into consideration viscous effects when the fluid is heated from below in a horizontal porous layer. The radiative heat transfer is heated using the differential approximation for ...

  6. Chemical heat pump

    Science.gov (United States)

    Greiner, Leonard

    1980-01-01

    A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer. The heat pump part of the system heats or cools a house or other structure through a combination of evaporation and absorption or, conversely, condensation and desorption, in a pair of containers. A set of automatic controls change the system for operation during winter and summer months and for daytime and nighttime operation to satisfactorily heat and cool a house during an entire year. The absorber chamber is subjected to solar heating during regeneration cycles and is covered by one or more layers of glass or other transparent material. Daytime home air used for heating the home is passed at appropriate flow rates between the absorber container and the first transparent cover layer in heat transfer relationship in a manner that greatly reduce eddies and resultant heat loss from the absorbant surface to ambient atmosphere.

  7. Analytical solution to laser short-pulse heating of microsized metal wire: volumetric and surface heat source considerations

    National Research Council Canada - National Science Library

    Yilbas, B.S; Al-Dweik, A.Y

    2012-01-01

    .... The volumetric heat source resembles absorption by irradiated field according to Lambert’s Beer law while a surface heat source represents short pulse heating through high intensity thermal contact at the surface...

  8. D-xylose absorption

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  9. Modelación de la transferencia de calor y masa en el absorbedor de una máquina de refrigeración por absorción. // Heat and mass transference modeling in the absorvetor of an absorption cooling device.

    Directory of Open Access Journals (Sweden)

    C. Cisneros Ramírez

    2003-01-01

    Full Text Available En este artículo se dan las expresiones que caracterizan el comportamiento de la temperatura y del producto coeficienteglobal de traspaso de calor (U por el área de traspaso de calor (A , de un absorbedor de una máquina de refrigeración porabsorción que trabaja con la solución amoniaco – agua.Palabras claves: Modelación, absorbedores, refrigeración por absorción.______________________________________________________________________________Abstract.In this article the expressions that characterize the temperature performance and the global heat exchange (U by the heatexchange area (A of the absorvetor of an absorption refrigerating equipment with aqua–ammonia solution are given.Key words: Model, absorber, absorption refrigeration.

  10. Absorptive coating for aluminum solar panels

    Science.gov (United States)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  11. Nanofibrous membrane-based absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  12. Absorption fluids data survey: 1989 update

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S. (Institute of Gas Technology, Chicago, IL (USA))

    1989-01-01

    This is an update of a series of prior reports on absorption fluids and data, ORNL/Sub/84-47989/1, 2, 3. It covers additional data developed and published mainly during 1985--88, and cites 44 additional references. Seventy-four different worldwide publications containing data relating to properties of binary, ternary, and multicomponent absorption fluids were identified. Of these, 30 manuscripts include applications of absorption fluid properties data toward evaluation, assessment, or design of chillers or heat pumps but do not include actual fluid properties data. The remaining 44 publications date as far back as 1929, but over 50% of these documents were published between 1985 and 1988. The texts of the 44 manuscripts are in English, German, Japanese, Russian, or French. The absorption fluids discussed in the 44 documents are combinations of 9 different refrigerant'' compounds and 30 single, 7 binary, and 1 ternary absorbent'' compounds. 44 refs., 21 tabs.

  13. A reconsideration of the evidence for Escherichia coli STa (heat stable) enterotoxin-driven fluid secretion: a new view of STa action and a new paradigm for fluid absorption.

    Science.gov (United States)

    Lucas, M L

    2001-01-01

    A review of the evidence for Escherichia coli STa causing fluid secretion in vito leads to the conclusion that the concept of STa acting through enhanced chloride secretion in order to derange intestinal function is unproven. However, a consistent effect of STa in the small intestine is on Na+/H+ exchange, leading to interruption of luminal acidification. A model for the action of STa, involving inhibition of Na+/H+ exchange, is proposed which explains the ability of STa to reduce absorption in vito but its inability to cause secretion in vito in contrast to its apparent secretory effect in vitro. The apparent ability to demonstrate secretion in vitro is shown to derive from methodologies which do not involve measurement of mass transport of water but instead, infer it from in vitro and in vivo proxy measurements. The in vitro demonstration of notional secretion after STa exposure can be reconciled with the proposed new model for fluid absorption in that cell swelling is argued to arise as a transient consequence of STa challenge followed by regulatory volume decrease. Evidence for this derangement model is presented in the form of observations derived from acute in vivo physiological studies and clinical studies on patients without the exchanger. This process of appraisal of the evidence for the mechanism of action of STa has led to a new model for fluid absorption. This is based on the formation of hypotonicity at the brush border luminal surface rather than hypertonicity within the lateral spaces as required by the present standing gradient model of fluid absorption. Evidence from the literature is presented for this new paradigm of water absorption, which may only be relevant for small intestine and other tissues that have Na+/H+ exchangers in contact with HCO-3-containing solutions but which may also be generalizable to all mammalian absorbing epithelial membranes.

  14. Continuous Light Absorption Photometer (CLAP) Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, Anne [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States)

    2014-05-01

    The Continuous Light Absorption Photometer (CLAP) measures the aerosol absorption of radiation at three visible wavelengths; 461, 522, and 653 nanometers (nm). Data from this measurement is used in radiative forcing calculations, atmospheric heating rates, and as a prediction of the amount of equivalent black carbon in atmospheric aerosol and in models of aerosol semi-direct forcing. Aerosol absorption measurements are essential to modeling the energy balance of the atmosphere.

  15. Optimization of absorption air-conditioning for solar energy applications

    Science.gov (United States)

    Perry, E. H.

    1976-01-01

    Improved performance of solar cooling systems using the lithium bromide water absorption cycle is investigated. Included are computer simulations of a solar-cooled house, analyses and measurements of heat transfer rates in absorption system components, and design and fabrication of various system components. A survey of solar collector convection suppression methods is presented.

  16. Heat cascading regenerative sorption heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1995-01-01

    A simple heat cascading regenerative sorption heat pump process with rejected or waste heat from a higher temperature chemisorption circuit (HTCC) powering a lower temperature physisorption circuit (LTPC) which provides a 30% total improvement over simple regenerative physisorption compression heat pumps when ammonia is both the chemisorbate and physisorbate, and a total improvement of 50% or more for LTPC having two pressure stages. The HTCC contains ammonia and a chemisorbent therefor contained in a plurality of canisters, a condenser-evaporator-radiator system, and a heater, operatively connected together. The LTPC contains ammonia and a physisorbent therefor contained in a plurality of compressors, a condenser-evaporator-radiator system, operatively connected together. A closed heat transfer circuit (CHTC) is provided which contains a flowing heat transfer liquid (FHTL) in thermal communication with each canister and each compressor for cascading heat from the HTCC to the LTPC. Heat is regenerated within the LTPC by transferring heat from one compressor to another. In one embodiment the regeneration is performed by another CHTC containing another FHTL in thermal communication with each compressor. In another embodiment the HTCC powers a lower temperature ammonia water absorption circuit (LTAWAC) which contains a generator-absorber system containing the absorbent, and a condenser-evaporator-radiator system, operatively connected together. The absorbent is water or an absorbent aqueous solution. A CHTC is provided which contains a FHTL in thermal communication with the generator for cascading heat from the HTCC to the LTAWAC. Heat is regenerated within the LTAWAC by transferring heat from the generator to the absorber. The chemical composition of the chemisorbent is different than the chemical composition of the physisorbent, and the absorbent. The chemical composition of the FHTL is different than the chemisorbent, the physisorbent, the absorbent, and ammonia.

  17. Review on absorption technology with emphasis on small capacity absorption machines

    Directory of Open Access Journals (Sweden)

    Labus Jerko M.

    2013-01-01

    Full Text Available The aim of this paper is to review the past achievements in the field of absorption systems, their potential and possible directions for future development. Various types of absorption systems and research on working fluids are discussed in detail. Among various applications, solar cooling and combined cooling, heating and power (CCHP are identified as two most promising applications for further development of absorption machines. Under the same framework, special attention is given to the small capacity absorption machines and their current status at the market. Although this technology looks promising, it is still in development and many issues are open. With respect to that fact, this paper covers all the relevant aspects for further development of small capacity absorption machines.

  18. Absorption-Line Studies of Seyfert Galaxies

    Science.gov (United States)

    Shull, J. Michael

    We propose to undertake a "reverberation analysis" of the variable absorption lines ill two Seyfert Galaxies (NGC 4051 and Mrk 279) to help understand the origin of intrinsic absorption lines in AGNs. Stich an analysis is a powerful tool for elucidating the radial distribution of absorbing gas in the broad-line region (BLR) and narrow-line region (NLR). Only two Seyferts have previously been studied with this technique: NGC 4151 (Bromage el al. 1985; Clavel et al. 1987) and NGC 3516 (Voit, Shull, and Begelman 1987). The absorption features have been interpreted as an outflow of ionized clouds from the nuclear region or from an accretion disk affected by UV/X-ray heating. Neither the source of the absorbing gas in these Seyferts nor the "gene" which distingishes them from other Seyferts is known. Until the 1984 onset of absorption in Mrk 279, broad self-absorbed. lines had been observed only in Seyferts of low intrinsic luminosity, such as NGC 4051. Mrk 279 is intrinsically much brighter, and therefore more quasar-like, than the other three absorptionline Seyfert I's in the CfA sample. Thus, it may show how the absorption phenomenon changes at higher luminosity and could bridge the gap between the low luminosity absorption-line Seyferts and the well-studied broad absorption-line (BAL) QSO's. In addition, Mrk 279's significant redshift will allow us to study, for the first time, the Ly-alpha line in an absorption-line Seyfert. With 3 US-1 shifts for each of these two underobserved Seyferts, we can double the number of objects in which absorption-line variability has been studied and investigate why the absorption-line strengths correlate or anti-correlate with the UV continuum.

  19. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  20. Experimental Characterization of Near-Infrared Laser Energy Absorption, Scattering, and Transmittance in Biological Tissue

    Science.gov (United States)

    2007-03-01

    upon incident radiation is absorption. Absorption is the process in which radiant energy is absorbed or taken up by a substance. General absorption...absorption. During absorption, the attenuation of the beam results in a transfer of energy to the tissue which is sometimes detected as heat, fluorescence ...water and tissue chromophores that include certain cellular pigments . The natural chromophores present include the biological pigments — specifically

  1. [Clothing and heat disorder].

    Science.gov (United States)

    Satsumoto, Yayoi

    2012-06-01

    The influence of the clothing material properties(like water absorbency and rapid dryness, water vapor absorption, water vapor permeability and air permeability) and the design factor of the clothing(like opening condition and fitting of clothing), which contributed to prevent heat disorder, was outlined. WBGT(wet-bulb globe temperature) is used to show a guideline for environmental limitation of activities to prevent heat disorder. As the safety function is more important than thermal comfort for some sportswear and protective clothing with high cover area, clothing itself increases the risk of heat disorder. WBGT is corrected by CAF (clothing adjustment factor) in wearing such kind of protective clothing.

  2. Membrane Gas Absorption

    NARCIS (Netherlands)

    Jansen, A.E.; Klaassen, R.; Feron, P.H.M.

    1995-01-01

    Membrane gas absorption processes are absorption processes utilising hollow fibre membranes as contacting media for gas and liquid flows. The principle of operation and engineering aspects are discussed, followed by discussion of a number of typical applications. Benefits in terms of operation,

  3. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  4. Solar absorption surface panel

    Science.gov (United States)

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  5. Radiation and MHD Boundary Layer Stagnation-Point of Nanofluid Flow towards a Stretching Sheet Embedded in a Porous Medium: Analysis of Suction/Injection and Heat Generation/Absorption with Effect of the Slip Model

    Directory of Open Access Journals (Sweden)

    Emad H. Aly

    2015-01-01

    Full Text Available In existence of the velocity slip model, suction/injection, and heat source/sink, the boundary layer flow near a stagnation-point over a heated stretching sheet in a porous medium saturated by a nanofluid, with effect of the thermal radiation and magnetic field, has been studied. The governing system of partial differential equations was transformed into a system of nonlinear ordinary equations using the appropriate similarity transforms. Then, the obtained system has been numerically solved by the Chebyshev pseudospectral differentiation matrix (ChPDM approach. It was found that, at some special cases, the current results are in a very good agreement with those presented in the literature. In addition, the flow velocity, surface shear stress, temperature, and concentration are strongly influenced on applying the slip model, which is, therefore, extremely important to predict the flow characteristics accurately in the nanofluid mechanics. It was proved that this velocity slip condition is mandatory and should be taken into account in nanoscale research; otherwise, false results and a spurious physical sight are to be gained. Further, it was deduced that the influence of the stream velocity and shear stress reaches very rapidly the stable manner for both cases of the velocity ratio. However, when this ratio is equal to one, the skin friction coefficient, reduced Nusselt number, and reduced Sherwood number are constant and equal to zero, 0.721082, and 3.06155, respectively. Furthermore, it was proved that the reduced Nusselt number decreases with increase of Brownian motion and thermophoresis; has a very weak effect on increasing Lewis number; increases with increase of Prandtl number; and is higher in the cases of suction, velocity ratio > 1 and heat source in comparison with injection, velocity ratio 1 in comparison with injection and velocity ratio < 1, respectively; and is approximately the same in the heat source and heat sink cases. Finally

  6. 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.

  7. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and ... having trouble with the heat. If a heat wave is predicted or happening… - Slow down. Avoid strenuous ...

  8. Iron Absorption in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Fanis Missirlis

    2013-05-01

    Full Text Available The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import, the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export and the role of ferritin in the process of iron acquisition (iron storage. We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration.

  9. Iron Absorption in Drosophila melanogaster

    Science.gov (United States)

    Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

    2013-01-01

    The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration. PMID:23686013

  10. Zeeman atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)

  11. Standard Practice for Evaluating Solar Absorptive Materials for Thermal Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice covers a testing methodology for evaluating absorptive materials used in flat plate or concentrating collectors, with concentrating ratios not to exceed five, for solar thermal applications. This practice is not intended to be used for the evaluation of absorptive surfaces that are (1) used in direct contact with, or suspended in, a heat-transfer liquid, (that is, trickle collectors, direct absorption fluids, etc.); (2) used in evacuated collectors; or (3) used in collectors without cover plate(s). 1.2 Test methods included in this practice are property measurement tests and aging tests. Property measurement tests provide for the determination of various properties of absorptive materials, for example, absorptance, emittance, and appearance. Aging tests provide for exposure of absorptive materials to environments that may induce changes in the properties of test specimens. Measuring properties before and after an aging test provides a means of determining the effect of the exposure. 1.3 Th...

  12. Optical absorption measurement system

    Science.gov (United States)

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  13. Absorption cooling device. Absorptions-Kuehlvorrichtung

    Energy Technology Data Exchange (ETDEWEB)

    Bourne, J.; Vardi, I.; Kimchi, Y.; Ben-Dror, J.

    1980-03-25

    The invention concerns improvements of absorption refrigerators, where a lithium chloride or lithium bromide/water cycle is used. According to the invention an inner separating or dividing structure between different functional parts of a machine of this type is provided. The structure contains two sections of wall, which are separated from one another by a suitable space, in order to achieve thermal insulation. This air space is provided with an opening in the direction towards the inside of the container and the opening is shielded to prevent the entry of liquids (in liquid or spray form).

  14. High increment of economy with modified absorption cooling process between 0 and -30 C; Effizienzsprung fuer die absorptive Kaelteerzeugung zwischen 0 und -30 C

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Hans [IFM Ingenieurbuero Dr.-Ing. H. Foerster, Magdeburg (Germany)

    2009-10-15

    With a new absorption cooling process for ammoniac-water as working substance it is able to use the heat off smokegas and at the same time the waste heat of motors for generation of chilling/freezing energy. The modified new process is very important for the economy in the decentralized energy-supply industry to utilization of waste heat. (orig.)

  15. Exergy analysis of the performance of low-temperature district heating system with geothermal heat pump

    Science.gov (United States)

    Sekret, Robert; Nitkiewicz, Anna

    2014-03-01

    Exergy analysis of low temperature geothermal heat plant with compressor and absorption heat pump was carried out. In these two concepts heat pumps are using geothermal water at 19.5 oC with spontaneous outflow 24 m3/h as a heat source. The research compares exergy efficiency and exergy destruction of considered systems and its components as well. For the purpose of analysis, the heating system was divided into five components: geothermal heat exchanger, heat pump, heat distribution, heat exchanger and electricity production and transportation. For considered systems the primary exergy consumption from renewable and non-renewable sources was estimated. The analysis was carried out for heat network temperature at 50/40 oC, and the quality regulation was assumed. The results of exergy analysis of the system with electrical and absorption heat pump show that exergy destruction during the whole heating season is lower for the system with electrical heat pump. The exergy efficiencies of total system are 12.8% and 11.2% for the system with electrical heat pump and absorption heat pump, respectively.

  16. Central cooling: absorptive chillers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-08-01

    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  17. Absorption of CO

    NARCIS (Netherlands)

    Shi, Liang; Gudjonsdottir, V.; Infante Ferreira, C.A.; Rexwinkel, Glenn; Kiss, Anton A.

    2017-01-01

    Compression resorption heat pumps (CRHP) are a promising option to upgrade waste heat from industry. Alternative working fluids can further improve the efficiency of CRHP. The ternary mixture NH3-CO2-H2O has been identified as a promising working fluid for CRHP and has the potential to further

  18. Ion and electron heating in ICRF heating experiments on LHD

    Energy Technology Data Exchange (ETDEWEB)

    Saito, K. [Nagoya Univ. (Japan). Faculty of Engineering; Kumazawa, R.; Mutoh, T. [National Inst. for Fusion Science, Toki, Gifu (Japan)] [and others

    2001-02-01

    This paper reports on the Ion Cyclotron Range of Frequency (ICRF) heating conducted in 1999 in the 3rd experimental campaign on the Large Helical Device (LHD) with an emphasis on the optimization of the heating regime. Specifically, an exhaustive study of seven different heating regimes was carried out by changing the RF frequency relative to the magnetic field intensity, and the dependence of the heating efficiency on H-minority concentration was investigated. It was found in the experiment that both ion and electron heating are attainable with the same experimental setup by properly choosing the frequency relative to the magnetic field intensity. In the cases of both electron heating and ion heating, the power absorption efficiency depends on the minority ion concentration. An optimum minority concentration exists in the ion heating case while, in the electron heating case, the efficiency increases with concentration monotonically. A simple model calculation is introduced to provide a heuristic understanding of these experimental results. Among the heating regimes examined in this experiment, one of the ion heating regimes was finally chosen as the optimized heating regime and various high performance discharges were realized with it. (author)

  19. Using lamb waves tomonitor moisture absorption thermally fatigues composite laminates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Sun; Cho, Youn Ho [School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of)

    2016-06-15

    Nondestructive evaluation for material health monitoring is important in aerospace industries. Composite laminates are exposed to heat cyclic loading and humid environment depending on flight conditions. Cyclic heat loading and moisture absorption may lead to material degradation such as matrix breaking, debonding, and delamination. In this paper, the moisture absorption ratio was investigated by measuring the Lamb wave velocity. The composite laminates were manufactured and subjected to different thermal aging cycles and moisture absorption. For various conditions of these cycles, not only changes in weight and also ultrasonic wave velocity were measured, and the Lamb wave velocity at various levels of moisture on a carbon-epoxy plate was investigated. Results from the experiment show a linear correlation between moisture absorption ratio and Lamb wave velocity at different thermal fatigue stages. The presented method can be applied as an alternative solution in the online monitoring of composite laminate moisture levels in commercial flights.

  20. Heat Stress

    Science.gov (United States)

    ... Publications and Products Programs Contact NIOSH NIOSH HEAT STRESS Recommend on Facebook Tweet Share Compartir NEW OSHA- ... hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational ...

  1. Cost reduction in absorption chillers: Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, R.W.

    1989-02-01

    A research program at Brookhaven National Laboratory (BNL) has addressed the possibility of dramatically lowering the first costs of absorption chillers through lowered material intensity and the use of lower cost materials, primarily in the heat exchangers which make up the bulk of the operating components of these systems. This must be done while retaining the best performance characteristics available today, a gross design point coefficient of performance (COP) of 1.3 and a net design (seasonal) average COP of 1.0 (0.90) in a directly fired, double effect unit. We have investigated several possible routes to these goals, and here report on these findings, focusing on the areas that appear most promising. The candidate technologies include the use of polymer film heat exchangers in several applications, the use of thin strips of new, corrosion resistant alloys to replace thicker, less impervious metals in applications exposed to gas flames, and copper or cupro-nickel foils in contact with system water. The use of such materials is only possible in the context of new heat exchanger and system designs, which are also discussed. To lend focus, we have concentrated on a directly fired double effect system providing capacity only. If successful, these techniques will also find wide applicability in heat pumps, cogeneration systems, solar cooling, heat recovery and chemical process heat transfer. 46 refs., 24 figs., 22 tabs.

  2. Unsteady MHD Mixed Convection Slip Flow of Casson Fluid over Nonlinearly Stretching Sheet Embedded in a Porous Medium with Chemical Reaction, Thermal Radiation, Heat Generation/Absorption and Convective Boundary Conditions.

    Science.gov (United States)

    Ullah, Imran; Bhattacharyya, Krishnendu; Shafie, Sharidan; Khan, Ilyas

    2016-01-01

    Numerical results are presented for the effect of first order chemical reaction and thermal radiation on mixed convection flow of Casson fluid in the presence of magnetic field. The flow is generated due to unsteady nonlinearly stretching sheet placed inside a porous medium. Convective conditions on wall temperature and wall concentration are also employed in the investigation. The governing partial differential equations are converted to ordinary differential equations using suitable transformations and then solved numerically via Keller-box method. It is noticed that fluid velocity rises with increase in radiation parameter in the case of assisting flow and is opposite in the case of opposing fluid while radiation parameter has no effect on fluid velocity in the forced convection. It is also seen that fluid velocity and concentration enhances in the case of generative chemical reaction whereas both profiles reduces in the case of destructive chemical reaction. Further, increase in local unsteadiness parameter reduces fluid velocity, temperature and concentration. Over all the effects of physical parameters on fluid velocity, temperature and concentration distribution as well as on the wall shear stress, heat and mass transfer rates are discussed in detail.

  3. Unsteady MHD Mixed Convection Slip Flow of Casson Fluid over Nonlinearly Stretching Sheet Embedded in a Porous Medium with Chemical Reaction, Thermal Radiation, Heat Generation/Absorption and Convective Boundary Conditions.

    Directory of Open Access Journals (Sweden)

    Imran Ullah

    Full Text Available Numerical results are presented for the effect of first order chemical reaction and thermal radiation on mixed convection flow of Casson fluid in the presence of magnetic field. The flow is generated due to unsteady nonlinearly stretching sheet placed inside a porous medium. Convective conditions on wall temperature and wall concentration are also employed in the investigation. The governing partial differential equations are converted to ordinary differential equations using suitable transformations and then solved numerically via Keller-box method. It is noticed that fluid velocity rises with increase in radiation parameter in the case of assisting flow and is opposite in the case of opposing fluid while radiation parameter has no effect on fluid velocity in the forced convection. It is also seen that fluid velocity and concentration enhances in the case of generative chemical reaction whereas both profiles reduces in the case of destructive chemical reaction. Further, increase in local unsteadiness parameter reduces fluid velocity, temperature and concentration. Over all the effects of physical parameters on fluid velocity, temperature and concentration distribution as well as on the wall shear stress, heat and mass transfer rates are discussed in detail.

  4. The Role of Absorption Cooling for Reaching Sustainable Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lindmark, Susanne

    2005-07-01

    This thesis focuses on the role and potential of absorption cooling in future energy systems. Two types of energy systems are investigated: a district energy system based on waste incineration and a distributed energy system with natural gas as fuel. In both cases, low temperature waste heat is used as driving energy for the absorption cooling. The main focus is to evaluate the absorption technology in an environmental perspective, in terms of reduced CO{sub 2} emissions. Economic evaluations are also performed. The reduced electricity when using absorption cooling instead of compression cooling is quantified and expressed as an increased net electrical yield. The results show that absorption cooling is an environmentally friendly way to produce cooling as it reduces the use of electrically driven cooling in the energy system and therefore also reduces global CO{sub 2} emissions. In the small-scale trigeneration system the electricity use is lowered with 84 % as compared to cooling production with compression chillers only. The CO{sub 2} emissions can be lowered to 45 CO{sub 2}/MWh{sub c} by using recoverable waste heat as driving heat for absorption chillers. However, the most cost effective cooling solution in a district energy system is a combination between absorption and compression cooling technologies according to the study. Absorption chillers have the potential to be suitable bottoming cycles for power production in distributed systems. Net electrical yields over 55 % may be reached in some cases with gas motors and absorption chillers. This small-scale system for cogeneration of power and cooling shows electrical efficiencies comparable to large-scale power plants and may contribute to reducing peak electricity demand associated with the cooling demand.

  5. Visual Absorption Capability

    Science.gov (United States)

    Lee Anderson; Jerry Mosier; Geoffrey Chandler

    1979-01-01

    Visual absorption capability (VAC) is a tool to assess a landscape's susceptibility to visual change caused by man's activities. This paper explores different descriptive approaches to VAC and addresses in depth the development of the VAC process used on the Klamath National Forest. Four biophysical factors were selected to assess VAC for the lands within the...

  6. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  7. CO2 Capture from Flue Gas by Phase Transitional Absorption

    Energy Technology Data Exchange (ETDEWEB)

    Liang Hu

    2009-06-30

    A novel absorption process called Phase Transitional Absorption was invented. What is the Phase Transitional Absorption? Phase Transitional Absorption is a two or multi phase absorption system, CO{sub 2} rich phase and CO{sub 2} lean phase. During Absorption, CO{sub 2} is accumulated in CO{sub 2} rich phase. After separating the two phases, CO{sub 2} rich phase is forward to regeneration. After regeneration, the regenerated CO{sub 2} rich phase combines CO{sub 2} lean phase to form absorbent again to complete the cycle. The advantage for Phase Transitional Absorption is obvious, significantly saving on regeneration energy. Because CO{sub 2} lean phase was separated before regeneration, only CO{sub 2} rich phase was forward to regeneration. The absorption system we developed has the features of high absorption rate, high loading and working capacity, low corrosion, low regeneration heat, no toxic to environment, etc. The process evaluation shows that our process is able to save 80% energy cost by comparing with MEA process.

  8. Effect of small ionospheric irregularities on radio wave absorption

    Science.gov (United States)

    Chen, H. C.; Fejer, J. A.

    1975-01-01

    The ionospheric absorption of a radio wave caused by small-scale irregularities with a gaussian autocorrelation function is calculated for various values of the linear scale height, the radio frequency, the scale size of the irregularities, and the mean-square fractional electron density fluctuations. The absorption is due to scattering of the radio wave into plasma oscillations by the irregularities. It is concluded that the absorption due to such irregularities with a mean-square fractional electron density deviation greater than about 0.000001 exceeds the normal collisional height-integrated absorption. Absorption of this type could play a significant part in heating experiments or in an ionosphere containing naturally occurring irregularities.

  9. Simulation of absorption refrigeration system for automobile application

    Directory of Open Access Journals (Sweden)

    Ramanathan Anand

    2008-01-01

    Full Text Available An automotive air-conditioning system based on absorption refrigeration cycle has been simulated. This waste heat driven vapor absorption refrigeration system is one alternate to the currently used vapour compression refrigeration system for automotive air-conditioning. Performance analysis of vapor absorption refrigeration system has been done by developing a steady-state simulation model to find the limitation of the proposed system. The water-lithium bromide pair is used as a working mixture for its favorable thermodynamic and transport properties compared to the conventional refrigerants utilized in vapor compression refrigeration applications. The pump power required for the proposed vapor absorption refrigeration system was found lesser than the power required to operate the compressor used in the conventional vapor compression refrigeration system. A possible arrangement of the absorption system for automobile application is proposed.

  10. Sensitivity of the CCM climate to enhanced cloud absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kiehl, J. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States)

    1995-09-01

    Recent indications suggest that clouds may be absorbing more solar radiation than was previously thought. This research investigates some of the evidence for this hypothesis; potential physical mechanisms are briefly discussed as well. The climatic implications of the enhanced absorption are investigated using the NCAR Community Climate Model (CCM). It is found that the model`s heat budget in the tropical warm pool agrees more closely with observations when enhanced absorption is included. On the whole, the addition of enhanced absorption improves the model`s performance in the tropics and degrades it in the extra-tropics. 3 figs.

  11. Steam Driven Triple Effect Absorption Solar Cooling System

    OpenAIRE

    Yabase, Hajime; Makita, Kazuyuki

    2012-01-01

    The authors propose a solar cooling system employing a steam-driven triple effect absorption chiller as a new technique for saving CO2 emission in the air conditioning field. The absorption chiller is a cooling machine using thermal energy as a drive source, and it is ideal for utilizing solar heat. In addition, by employing a triple effect absorption chiller of high efficiency, a high energy saving effect and a significant CO2 saving effect can be expected. As a result of studies, it has bee...

  12. Aerosol optical absorption measurements with photoacoustic spectroscopy

    Science.gov (United States)

    Liu, Kun; Wang, Lei; Liu, Qiang; Wang, Guishi; Tan, Tu; Zhang, Weijun; Chen, Weidong; Gao, Xiaoming

    2015-04-01

    Many parameters related to radiative forcing in climate research are known only with large uncertainties. And one of the largest uncertainties in global radiative forcing is the contribution from aerosols. Aerosols can scatter or absorb the electromagnetic radiation, thus may have negative or positive effects on the radiative forcing of the atmosphere, respectively [1]. And the magnitude of the effect is directly related to the quantity of light absorbed by aerosols [2,3]. Thus, sensitivity and precision measurement of aerosol optical absorption is crucial for climate research. Photoacoustic spectroscopy (PAS) is commonly recognized as one of the best candidates to measure the light absorption of aerosols [4]. A PAS based sensor for aerosol optical absorption measurement was developed. A 532 nm semiconductor laser with an effective power of 160 mW was used as a light source of the PAS sensor. The PAS sensor was calibrated by using known concentration NO2. The minimum detectable optical absorption coefficient (OAC) of aerosol was determined to be 1 Mm-1. 24 hours continues measurement of OAC of aerosol in the ambient air was carried out. And a novel three wavelength PAS aerosol OAC sensor is in development for analysis of aerosol wavelength-dependent absorption Angstrom coefficient. Reference [1] U. Lohmann and J. Feichter, Global indirect aerosol effects: a review, Atmos. Chem. Phys. 5, 715-737 (2005) [2] M. Z. Jacobson, Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature 409, 695-697 (2001) [3] V. Ramanathan and G. Carmichae, Global and regional climate changes due to black carbon, nature geoscience 1, 221-227 (2008) [4] W.P Arnott, H. Moosmuller, C. F. Rogers, T. Jin, and R. Bruch, Photoacoustic spectrometer for measuring light absorption by aerosol: instrument description. Atmos. Environ. 33, 2845-2852 (1999).

  13. Thermal radiation heat transfer

    CERN Document Server

    Howell, John R; Mengüç, M Pinar

    2011-01-01

    Providing a comprehensive overview of the radiative behavior and properties of materials, the fifth edition of this classic textbook describes the physics of radiative heat transfer, development of relevant analysis methods, and associated mathematical and numerical techniques. Retaining the salient features and fundamental coverage that have made it popular, Thermal Radiation Heat Transfer, Fifth Edition has been carefully streamlined to omit superfluous material, yet enhanced to update information with extensive references. Includes four new chapters on Inverse Methods, Electromagnetic Theory, Scattering and Absorption by Particles, and Near-Field Radiative Transfer Keeping pace with significant developments, this book begins by addressing the radiative properties of blackbody and opaque materials, and how they are predicted using electromagnetic theory and obtained through measurements. It discusses radiative exchange in enclosures without any radiating medium between the surfaces-and where heat conduction...

  14. Heat pumps

    CERN Document Server

    Macmichael, DBA

    1988-01-01

    A fully revised and extended account of the design, manufacture and use of heat pumps in both industrial and domestic applications. Topics covered include a detailed description of the various heat pump cycles, the components of a heat pump system - drive, compressor, heat exchangers etc., and the more practical considerations to be taken into account in their selection.

  15. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary ...... processes, with emphasis on exploitative learning. Before concluding, the paper addresses implications for theory and practice and limitations of this study....

  16. Relic Neutrino Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  17. Magnetohydrodynamic stokes problem for a dissipative heat ...

    African Journals Online (AJOL)

    Heat and Mass transfer MHD stokes problem for a dissipative heat generating fluid with radiation absorption, mass diffusion, Hall and ion-slip currents is presented. The set of governing equations for the problem are solved by a finite difference algorithm. Effects of the various parameters in the laminar boundary layer on ...

  18. Improving the system of absorption unit refrigeration

    Directory of Open Access Journals (Sweden)

    Pokhol'chenko V. A.

    2016-12-01

    Full Text Available The problems of improving the absorption stove cooling system for high quality liquid smoke producing have been discussed in the paper. There is absorption stove construction presented which includes absorber, heat exchanger, low-temperature chamber, ultrasound radiator, and water spray generator. The data on the color depending of the experimental liquid smoke on main factors influencing the process – the coolant temperature and amount of fuel burned – have been presented. The specific surface of the fuel mass fraction of water in the fuel has been determined according to standard procedures. Transparency, color and intensity of staining smoke fluid have been determined organoleptically. The liquid smoke according to the requirements of the current normative documents on safety performance indicators has been tested by standard methods: determination of benzo(apyrene, phenol compounds and heavy metals. The equation for estimation the complex quality criterion of experimental liquid smoke on the basis of its chemical composition has been presented. The main factors influencing the complex quality criteria of experimental liquid smoke have been given there. They include the sound pressure level, amount of wood raw material required for pyrolysis, heat exchanging surface, refrigerant temperature, and ultrasound water spray generator efficiency. After processing the experimental data the regression equation of producing liquid smoke by absorption has been received. With the help of the mathematical modeling for absorption process of smoke components by fine-dispersed spray the rational parameters of liquid smoke processing have been founded. The project of technological instructions for the liquid smoke production by using the wood smoke and acoustically generated aerosol has been designed. The project of technical requirement "Liquid smoke Antonio Silver" has been designed as well; it has been tested at producing the commercial batch of dried

  19. Absorption in periodic layered structures

    OpenAIRE

    Moroz, Alexander; Tip, Adriaan; Combes, Jean-Michel

    2000-01-01

    Photonic band structure of metal-dielectric and semiconductor-dielectric layered structures are studied in the presence of a strong absorption. It is shown that absorption can enlarge some gaps by as much as 50%.

  20. Heat pumps

    CERN Document Server

    Brodowicz, Kazimierz; Wyszynski, M L; Wyszynski

    2013-01-01

    Heat pumps and related technology are in widespread use in industrial processes and installations. This book presents a unified, comprehensive and systematic treatment of the design and operation of both compression and sorption heat pumps. Heat pump thermodynamics, the choice of working fluid and the characteristics of low temperature heat sources and their application to heat pumps are covered in detail.Economic aspects are discussed and the extensive use of the exergy concept in evaluating performance of heat pumps is a unique feature of the book. The thermodynamic and chemical properties o

  1. Generator-Absorber heat exchange transfer apparatus and method using an intermediate liquor

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

    1996-11-05

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium where the working solution has an intermediate liquor concentration.

  2. Generator-Absorber heat exchange transfer apparatus and method using an intermediate liquor

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, B.A.; Zawacki, T.S.

    1996-11-05

    Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium where the working solution has an intermediate liquor concentration. 13 figs.

  3. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of fluorination.

  4. Absorption characteristics of bacteriorhodopsin molecules

    Indian Academy of Sciences (India)

    The analytical expression for the absorption coefficient of BR film is applied to study the absorption characteristics of BR molecules in a typical laser system operating at funda- mental wavelength 514 nm. The experimental data available for the absorption coefficients of the levels B and M corresponding to the wavelength ...

  5. The Impact on Wind Power Integration from Geothermal Absorption

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2012-01-01

    and lowtemperature geothermal resources. The analyses have also demonstrated that the municipality will still rely heavily on surrounding areas for electric load balancing assistance. With a departure in a previously elaborated 100% renewable energy scenario, this paper investigates how absorption heat pumps (AHP...

  6. improvement to the design of a solid absorption solar refrigerator

    African Journals Online (AJOL)

    user

    The paper presents the highlights of the design of an existing solid absorption solar refrigerator, using CaCl2 ... on the coupling of auxiliary heating systems to the solar powered refrigerator. A re-design of the ... Six collector tubes, having a perforated co-axial galvanised inner steel tube, were bonded to the plate at 152 mm.

  7. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  8. Absorption in dielectric models

    CERN Document Server

    Churchill, R J

    2015-01-01

    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  9. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)

    IOAN MAC

    2009-01-01

    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  10. HEAT RECUPERATION

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2011-01-01

    Full Text Available Heat recovery is an effective method of shortening specific energy consumption. new constructions of recuperators for heating and cupola furnaces have been designed and successfully introduced. two-stage recuperator with computer control providing blast heating up to 600 °C and reducing fuel consumption by 30% is of special interest.

  11. Absorption and adsorption chillers applied to air conditioning systems

    Science.gov (United States)

    Kuczyńska, Agnieszka; Szaflik, Władysław

    2010-07-01

    This work presents an application possibility of sorption refrigerators driven by low temperature fluid for air conditioning of buildings. Thermodynamic models were formulated and absorption LiBr-water chiller with 10 kW cooling power as well as adsorption chiller with silica gel bed were investigated. Both of them are using water for desorption process with temperature Tdes = 80 °C. Coefficient of performance (COP) for both cooling cycles was analyzed in the same conditions of the driving heat source, cooling water Tc = 25 °C and temperature in evaporator Tevap = 5 °C. In this study, the computer software EES was used to investigate the performance of absorption heat pump system and its behaviour in configuration with geothermal heat source.

  12. The production of carbon dioxide from flue gas by membrane gas absorption

    NARCIS (Netherlands)

    Feron, P.H.M.; Jansen, A.E.

    1997-01-01

    The use of membrane gas absorption for carbon dioxide production from flue gases is discussed with special reference to the combined supply of heat and carbon dioxide to greenhouses. Novel absorption liquids are introduced which show an improved performance in terms of system stability and mass

  13. Electromagnetic-radiation absorption by water

    Science.gov (United States)

    Lunkenheimer, P.; Emmert, S.; Gulich, R.; Köhler, M.; Wolf, M.; Schwab, M.; Loidl, A.

    2017-12-01

    Why does a microwave oven work? How does biological tissue absorb electromagnetic radiation? Astonishingly, we do not have a definite answer to these simple questions because the microscopic processes governing the absorption of electromagnetic waves by water are largely unclarified. This absorption can be quantified by dielectric loss spectra, which reveal a huge peak at a frequency of the exciting electric field of about 20 GHz and a gradual tailing off toward higher frequencies. The microscopic interpretation of such spectra is highly controversial and various superpositions of relaxation and resonance processes ascribed to single-molecule or molecule-cluster motions have been proposed for their analysis. By combining dielectric, microwave, THz, and far-infrared spectroscopy, here we provide nearly continuous temperature-dependent broadband spectra of water. Moreover, we find that corresponding spectra for aqueous solutions reveal the same features as pure water. However, in contrast to the latter, crystallization in these solutions can be avoided by supercooling. As different spectral contributions tend to disentangle at low temperatures, this enables us to deconvolute them when approaching the glass transition under cooling. We find that the overall spectral development, including the 20 GHz feature (employed for microwave heating), closely resembles the behavior known for common supercooled liquids. Thus water's absorption of electromagnetic waves at room temperature is not unusual but very similar to that of glass-forming liquids at elevated temperatures, deep in the low-viscosity liquid regime, and should be interpreted along similar lines.

  14. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods......Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients...

  15. Moving heat source in a confined channel: Heat transfer and boiling in endovenous laser ablation of varicose veins

    NARCIS (Netherlands)

    de Boer, Amit; Oliveira, Jorge L. G.; van der Geld, Cees W. M.; Malskat, Wendy S. J.; van den Bos, Renate; Nijsten, Tamar; van Gemert, Martin J. C.

    2017-01-01

    Motion of a moving laser light heat source in a confined volume has important applications such as in endovenous laser ablation (EVLA) of varicose veins. This light heats up the fluid and the wall volume by absorption and heat conduction. The present study compares the flow and temperature fields in

  16. On the potential of uneven heating in heterogeneous food media with dielectric heating

    NARCIS (Netherlands)

    Veen, van der M.E.; Goot, van der A.J.; Vriezinga, C.A.; Meester, de J.W.G.; Boom, R.M.

    2004-01-01

    A dynamic model was developed describing dielectric heating dynamics of a heterogeneous material, in which the dispersed phase heats more quickly than the surrounding phase. The model includes effects of scattering by small particles, absorption and differences in thermal and conduction properties,

  17. Heated Goggles

    Science.gov (United States)

    1978-01-01

    The electrically heated ski goggles shown incorporate technology similar to that once used in Apollo astronauts' helmet visors, and for the same reason-providing fogfree sight in an activity that demands total vision. Defogging is accomplished by applying heat to prevent moisture condensation. Electric heat is supplied by a small battery built into the h goggles' headband. Heat is spread across the lenses by means of an invisible coating of electrically conductive metallic film. The goggles were introduced to the market last fall. They were designed by Sierracin Corporation, Sylmar, California, specialists in the field of heated transparent materials. The company produces heated windshields for military planes and for such civil aircraft as the Boeing 747, McDonnell Douglas DC-10 and Lockheed L-1011 TriStar.

  18. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  19. Parametric analysis of a double-effect steam absorption chiller

    Science.gov (United States)

    Mohammed Salih Ahmed, Mojahid Sid Ahmed; Gilani, Syed Ihtsham Ul-Haq

    2012-06-01

    The development in the field of refrigeration and cooling systems based on absorption cycles has attained its own internal dynamic in the last decade. A major obstacle for developing model is the lack of available component specifications. These specifications are commonly proprietary of the chiller's manufacturers and normally the available information is not sufficient. This work presented a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations. The chiller studied is 1250 RT (Refrigeration Tons) using lithium bromide -water as working pair. The mathematical equations that govern the operation of the steam absorption chiller are developed, and from the available design data the values of the overall heat transfer coefficient multiplied by the heat exchanger surface area and the characteristics of each component of the absorption chiller at the design point are calculated. For thermo physical and thermodynamic properties for lithium bromide-water solution, set of computationally efficient formulations are used. The model gives the required information about temperature, concentration, and flow rate at each state point of the system. The model calculates the heat load at each component as well as the performance of the system.

  20. Coherent perfect absorption in deeply subwavelength films in the single photon regime

    CERN Document Server

    Roger, Thomas; Bolduc, Eliot; Valente, Joao; Heitz, Julius J F; Jeffers, John; Soci, Cesare; Leach, Jonathan; Couteau, Christophe; Zheludev, Nikolay; Faccio, Daniele

    2016-01-01

    The technologies of heating, photovoltaics, water photocatalysis and artificial photosynthesis depend on the absorption of light and novel approaches such as coherent absorption from a standing wave promise total dissipation of energy. Extending the control of absorption down to very low light levels and eventually to the single photon regime is of great interest yet remains largely unexplored. Here we demonstrate the coherent absorption of single photons in a deeply sub-wavelength 50% absorber. We show that while absorption of photons from a travelling wave is probabilistic, standing wave absorption can be observed deterministically, with nearly unitary probability of coupling a photon into a mode of the material, e.g. a localised plasmon when this is a metamaterial excited at the plasmon resonance. These results bring a better understanding of the coherent absorption process, which is of central importance for light harvesting, detection, sensing and photonic data processing applications.

  1. Exergoeconomic optimal performance of an irreversible closed Brayton cycle combined cooling, heating and power plant

    National Research Council Canada - National Science Library

    Feng, Huijun; Chen, Lingen; Sun, Fengrui

    2011-01-01

    A combined cooling, heating and power (CCHP) plant model composed of an irreversible closed Brayton cycle and an endoreversible four-heat-reservoir absorption refrigeration cycle is established by using finite time thermodynamic...

  2. HIFU treatment time reduction through heating approach optimisation.

    Science.gov (United States)

    Coon, Joshua; Todd, Nick; Roemer, Robert

    2012-01-01

    This study evaluated the HIFU treatment time reductions attainable for several scan paths when optimising the heating approach used (single, discrete pulses versus volumetric scanning) and the paths' focal zone heating locations'; number (N(FZL)), spacings, sequencing order, number of heating cycles (N(CYCLES)), and heating times. Also evaluated were the effects of focal zone size, increased tissue absorptivity due to heating, and optimisation technique. Treatments of homogeneous constant property tumours were simulated for several simple generic tumour shapes and sizes. The concentrated heating approach (which delivered the desired thermal dose to each location in one discrete heating pulse (N(CYCLES) = 1)) was compared to the fractionated heating approach (which dosed the tumour using multiple, shorter pulses repeatedly scanned around the heating path (i.e. 'volumetric scanning' with N(CYCLES) > 1)). Treatment times were minimised using both simultaneous, collective pulse optimisation (which used full a priori knowledge of the interacting effects of all pulses) and sequential, single pulse optimisation (which used only the information from previous pulses and cooling of the current pulse). Optimised concentrated heating always had shorter treatment times than optimised fractionated heating, and concentrated heating resulted in less normal tissue heating. When large, rapid tissue absorptivity changes were present (doubled or quadrupled immediately after heating) the optimal ordering of the scan path's sequence of focal zone locations changed. Concentrated heating yields significant treatment time reductions and less normal tissue heating when compared to all fractionated scanning approaches, e.g. volumetric scanning.

  3. A mid-infrared absorption diagnostic for acetylene detection

    Science.gov (United States)

    KC, Utsav; Nasir, Ehson F.; Farooq, Aamir

    2015-08-01

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm-1 over a wide range of temperatures (1000-2200 K) and pressures (1-5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene.

  4. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.

    2016-01-01

    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains...

  5. Wave energy absorption by ducks

    DEFF Research Database (Denmark)

    Kurniawan, Adi

    2017-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle....

  6. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  7. Investigating cloud absorption effects: Global absorption properties of black carbon, tar balls, and soil dust in clouds and aerosols

    Science.gov (United States)

    Jacobson, Mark Z.

    2012-03-01

    This study examines modeled properties of black carbon (BC), tar ball (TB), and soil dust (SD) absorption within clouds and aerosols to understand better Cloud Absorption Effects I and II, which are defined as the effects on cloud heating of absorbing inclusions in hydrometeor particles and of absorbing aerosol particles interstitially between hydrometeor particles at their actual relative humidity (RH), respectively. The globally and annually averaged modeled 550 nm aerosol mass absorption coefficient (AMAC) of externally mixed BC was 6.72 (6.3-7.3) m2/g, within the laboratory range (6.3-8.7 m2/g). The global AMAC of internally mixed (IM) BC was 16.2 (13.9-18.2) m2/g, less than the measured maximum at 100% RH (23 m2/g). The resulting AMAC amplification factor due to internal mixing was 2.41 (2-2.9), with highest values in high RH regions. The global 650 nm hydrometeor mass absorption coefficient (HMAC) due to BC inclusions was 17.7 (10.6-19) m2/g, ˜9.3% higher than that of the IM-AMAC. The 650 nm HMACs of TBs and SD were half and 1/190th, respectively, that of BC. Modeled aerosol absorption optical depths were consistent with data. In column tests, BC inclusions in low and mid clouds (CAE I) gave column-integrated BC heating rates ˜200% and 235%, respectively, those of interstitial BC at the actual cloud RH (CAE II), which itself gave heating rates ˜120% and ˜130%, respectively, those of interstitial BC at the clear-sky RH. Globally, cloud optical depth increased then decreased with increasing aerosol optical depth, consistent with boomerang curves from satellite studies. Thus, CAEs, which are largely ignored, heat clouds significantly.

  8. Glass heat pipe evacuated tube solar collector

    Science.gov (United States)

    McConnell, Robert D.; Vansant, James H.

    1984-01-01

    A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

  9. Heat Stroke

    DEFF Research Database (Denmark)

    Mørch, Sofie Søndergaard; Andersen, Johnny Dohn Holmgren; Bestle, Morten Heiberg

    2017-01-01

    Heat stroke is an acute, life-threatening emergency characterized clinically by elevated body temperature and central nervous system dysfunction. Early recognition and treatment including aggressive cooling and management of life-threatening systemic complications are essential to reduce morbidity...... and mortality. This case report describes two Danish patients diagnosed with heat stroke syndrome during a heat wave in the summer of 2014. Both patients were morbidly obese and had several predisposing illnesses. However since heat stroke is a rare condition in areas with temperate climate, they were...... not diagnosed until several days after admittance; hence treatment with cooling was delayed. Both patients were admitted to the intensive care unit, where they were treated with an external cooling device and received treatment for complications. Both cases ended fatally. As global warming continues, more heat...

  10. Combat Vehicle Cooling/Heating Design Investigation.

    Science.gov (United States)

    1981-09-01

    Robert E., and Gaudio, Ralph, Jr.; "Application of the Ranque - Hilsch Vortex Tube to Aircrew Cooling Problems" Report AMRL-TR-67-124; Wright-Patterson... Tube 3-7 3.6 Expendable Heat Sink 3-9 3.7 Absorption Cooling 3-10 3.8 Evaporative Cooling 3-11 3.9 Summary 3-12 4.0 COMPARATIVE SYSTEM PERFORMANCE 4...3-6 3-5 Vortex Tube System Schematic 3-8 3-6 Expendable Heat Sink System Schematic 3-9 3-7 Absorption Cooling System Schematic 3-10 4-1 Air Cycle

  11. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1994-01-01

    It is approximately 10 years since the Third Edition of Heat Pipes was published and the text is now established as the standard work on the subject. This new edition has been extensively updated, with revisions to most chapters. The introduction of new working fluids and extended life test data have been taken into account in chapter 3. A number of new types of heat pipes have become popular, and others have proved less effective. This is reflected in the contents of chapter 5. Heat pipes are employed in a wide range of applications, including electronics cooling, diecasting and injection mo

  12. Aerosol Absorption Near Beijing During EAST-AIRE

    Science.gov (United States)

    Yang, M.; Howell, S.; Huebert, B.; Zhuang, J.

    2006-12-01

    To understand the aerosol absorption that had been observed offshore during ACE-Asia, we took a suite of instruments (including a 7 wavelength aethalometer) to a site 70 km ESE of Beijing in March of 2005 to measure the wavelength dependence of aerosol absorption as a part of the EAST-AIRE program. Confidence in filter methods suffers a bit because several corrections are required to estimate ambient absorption from particles on a filter: there is enhancement by multiple scatter from the filter's matrix, shadowing by thick cakes of collected particles, and scattering by co-collected aerosols, to name a few. We encountered mild dust, heavy pollution, relatively clean air, coal-burning chimney plumes, industrial plumes, and biomass burning, often at separate times. The absorption Angstrom exponent was always greater than 1, averaging 1.5: in the UV and violet there is an enhanced absorption over what one would expect of black carbon. If we assume that BC is responsible for all the absorption at 950 nm and that it has an Angstrom coefficient of 1.0 (yielding a specific absorbance of about 9 m2g-1 at 550 nm), the remaining absorption Angstrom exponent in the visible averaged 3.2. However, the 370-950 nm absorption spectrum of the remainder looked very much like the clay and hematite absorption spectra published by Sokolik and Toon, including a striking UV absorption and a characteristic dip around 660 nm (e.g., not a power law shape). This is not surprising, since clay is both a frequent component of dust and is used as a binder in the charcoal briquettes that are widely used in China for heating and cooking. We found single-scatter albedos virtually always less than 0.9, averaging 0.82. In the presence of dust, the SSA increased toward the IR. We also find that the clay spectrum explains virtually all the non-BC absorption, so there must not be much brown carbon present. Our confidence in these on-filter absorption measurements is increased by the fact that we

  13. Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

  14. The expected time until absorption when absorption is not certain

    OpenAIRE

    Walker, D. M.

    1998-01-01

    This paper considers continuous-time Markov chains whose state space consists of an irreducible class, , and an absorbing state which is accessible from . The purpose is to provide a way to determine the expected time to absorption conditional on such time being finite, in the case where absorption occurs with probability less than 1. The results are illustrated by applications to the general birth and death process and the linear birth, death and catastrophe process.

  15. Plasma sprayed coatings for RF wave absorption

    Science.gov (United States)

    Nanobashvili, S.; Matějíček, J.; Žáček, F.; Stőckel, J.; Chráska, P.; Brožek, V.

    2002-12-01

    High requirements for fusion reactor materials and for experimental fusion devices have led within the fusion community to the development and testing of various coatings of the surfaces of in-vessel components and biological shields for microwave heating systems. Based on contacts with ITER, W7X and the Spanish Stellarator TJ-II, IPP Prague has initiated a development, production and test program on various low- Z materials. This paper reports on the production, development and properties of B 4C, Si and Al 2O 3 coatings sprayed by water stabilized plasma. Main focus is on their radio frequency wave reflection properties. Further characterization includes the coating structure by microscopy, phase composition by X-ray diffraction and oxygen content measurement by atomic absorption spectroscopy. The results are discussed with respect to processing conditions as well as potential application.

  16. Plasma sprayed coatings for RF wave absorption

    Energy Technology Data Exchange (ETDEWEB)

    Nanobashvili, S.; Matejicek, J. E-mail: jmatejic@ipp.cas.cz; Zacek, F.; Stockel, J.; Chraska, P.; Brozek, V

    2002-12-01

    High requirements for fusion reactor materials and for experimental fusion devices have led within the fusion community to the development and testing of various coatings of the surfaces of in-vessel components and biological shields for microwave heating systems. Based on contacts with ITER, W7X and the Spanish Stellarator TJ-II, IPP Prague has initiated a development, production and test program on various low-Z materials. This paper reports on the production, development and properties of B{sub 4}C, Si and Al{sub 2}O{sub 3} coatings sprayed by water stabilized plasma. Main focus is on their radio frequency wave reflection properties. Further characterization includes the coating structure by microscopy, phase composition by X-ray diffraction and oxygen content measurement by atomic absorption spectroscopy. The results are discussed with respect to processing conditions as well as potential application.

  17. IHT: Tools for Computing Insolation Absorption by Particle Laden Flows

    Energy Technology Data Exchange (ETDEWEB)

    Grout, R. W.

    2013-10-01

    This report describes IHT, a toolkit for computing radiative heat exchange between particles. Well suited for insolation absorption computations, it is also has potential applications in combustion (sooting flames), biomass gasification processes and similar processes. The algorithm is based on the 'Photon Monte Carlo' approach and implemented in a library that can be interfaced with a variety of computational fluid dynamics codes to analyze radiative heat transfer in particle-laden flows. The emphasis in this report is on the data structures and organization of IHT for developers seeking to use the IHT toolkit to add Photon Monte Carlo capabilities to their own codes.

  18. Nonlinear Spatial Absorption of Alfven Waves by Dissipative Plasma

    Science.gov (United States)

    Gavrikov, M. B.; Taiurskii, A. A.

    2017-11-01

    A mathematical model is proposed for explaining anomalous heating of the solar corona by Alfven waves generated in lower, much cooler, layers of the Sun. Numerical analysis shows that the absorption of Alfven waves occurs at wavelengths of the order of skin depth, in which case neither the classical nor Hall’s MHD equations are applicable. Therefore, our research was based on the equations of two-fluid magnetohydrodynamics that fully take into account the inertia of the electrons. This investigation reveals some important features of the absorption process, in particular: the depth of the heated layer of the solar corona is finite and the parameters of the Alfven waves stabilize to a quasi-stationary regime whose parameters can be found.

  19. Effects Of Heat Sinks On VPPA Welds

    Science.gov (United States)

    Nunes, Arthur C.; Steranka, Paul O., Jr.

    1991-01-01

    Report describes theoretical and experimental study of absorption of heat by metal blocks in contact with metal plate while plate subjected to variable-polarity plasma-arc (VPPA) welding. Purpose of study to contribute to development of comprehensive mathematical model of temperature in weld region. Also relevant to welding of thin sheets of metal to thick blocks of metal, heat treatment of metals, and hotspots in engines.

  20. Reaction rate in a heat bath

    CERN Document Server

    Jacob, Maurice René Michel

    1992-01-01

    We show in detail how the presence of a heat bath of photons effectively gives charged particles in the final state of a decay process a temperature-dependent mass, and changes the effective strength of the force responsible for the decay. At low temperature, gauge invariance causes both these effects to be largely cancelled by absorption of photons from the heat bath and by stimulated emission into it, but at high temperature the temperature-dependent mass is the dominant feature.

  1. Reproducibility of The Random Incidence Absorption Coefficient Converted From the Sabine Absorption Coefficient

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Chang, Ji-ho

    2015-01-01

    Absorption coefficients measured in reverberation chambers, Sabine absorption coefficients, suffer from two major problems. Firstly, they sometimes exceed unity. Secondly, the reproducibility of the Sabine absorption coefficients is quite poor, meaning that the Sabine absorption coefficients vary...

  2. A microwave power absorption characterization of YMnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, G. [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360, Coyoacan DF 04510 (Mexico)], E-mail: memodin@yahoo.com; Montiel, H. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico de la Universidad Nacional Autonoma de Mexico, Mexico DF 04510 (Mexico); Castellanos, M.A. [Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Mexico DF 04510 (Mexico); Heiras, J. [Centro de Ciencias de la Materia Condensada, Universidad Nacional Autonoma de Mexico, Apartado Postal 2681, Ensenada BC 22800 (Mexico); Valenzuela, R. [Departamento de Materiales Metalicos y Ceramicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360, Coyoacan DF 04510 (Mexico)

    2008-05-25

    We report on the effects of temperature and dc magnetic field on the microwave power absorption measurements at X-band (8.8-9.8 GHz), in powder samples of YMnO{sub 3} (YM). Two techniques are used: magnetically modulated microwave absorption spectroscopy (MAMMAS) and low-field microwave absorption spectroscopy (LFMAS). The measurements were performed in the 77-520 K temperature range. MAMMAS response showed distinctive features associated with microwave absorption by magnetic and electric dipoles; at low and high temperatures, the paramagnetic and dielectric absorptions of microwave are dominant, respectively. The profiles obtained by plotting the slope vs. temperature of the LFMAS line, while cooling or heating, are similar to those detected by the MAMMAS technique. We conclude that both measurements are a manifestation of the same response to electromagnetic absorption, in which the same physical processes take place.

  3. Modular Heat Exchanger With Integral Heat Pipe

    Science.gov (United States)

    Schreiber, Jeffrey G.

    1992-01-01

    Modular heat exchanger with integral heat pipe transports heat from source to Stirling engine. Alternative to heat exchangers depending on integrities of thousands of brazed joints, contains only 40 brazed tubes.

  4. Exergoeconomic optimization of an ammonia-water hybrid heat pump for heat supply in a spray drying facility

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

    2014-01-01

    rate is 100,000 m3/h which yields a heat load of 6.1 MW. The exhaust air from the drying process is 80 XC. The implementation of an ammonia-water hybrid absorption-compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation......Spray drying facilities are among the most energy intensive industrial processes. Using a heat pump to recover waste heat and replace gas combustion has the potential to attain both economic and emissions savings. In the case examined a drying gas of ambient air is heated to 200 XC. The inlet flow...

  5. Low-Cost Gas Heat Pump for Building Space Heating

    Energy Technology Data Exchange (ETDEWEB)

    Garrabrant, Michael [Stone Mountain Technologies, Inc., Johnson City, TN (United States); Keinath, Christopher [Stone Mountain Technologies, Inc., Johnson City, TN (United States)

    2016-10-11

    Gas-fired residential space heating in the U.S is predominantly supplied by furnaces and boilers. These technologies have been approaching their thermodynamic limit over the past 30 years and improvements for high efficiency units have approached a point of diminishing return. Electric heat pumps are growing in popularity but their heating performance at low ambient temperatures is poor. The development of a low-cost gas absorption heat pump would offer a significant improvement to current furnaces and boilers, and in heating dominated climate zones when compared to electric heat pumps. Gas absorption heat pumps (GAHP) exceed the traditional limit of thermal efficiency encountered by typical furnaces and boilers, and maintain high levels of performance at low ambient temperatures. The project team designed and demonstrated two low-cost packaged prototype GAHP space heating systems during the course of this investigation. Led by Stone Mountain Technologies Inc. (SMTI), with support from A.O. Smith, and the Gas Technology Institute (GTI), the cross-functional team completed research and development tasks including cycle modeling, 8× scaling of a compact solution pump, combustion system development, breadboard evaluation, fabrication of two packaged prototype units, third party testing of the first prototype, and the evaluation of cost and energy savings compared to high and minimum efficiency gas options. Over the course of the project and with the fabrication of two Alpha prototypes it was shown that this technology met or exceeded most of the stated project targets. At ambient temperatures of 47, 35, 17 and -13°F the prototypes achieved gas based coefficients of performance of 1.50, 1.44, 1.37, and 1.17, respectively. Both units operated with parasitic loads well below the 750 watt target with the second Alpha prototype operating 75-100 watts below the first Alpha prototype. Modulation of the units at 4:1 was achieved with the project goal of 2:1 modulation

  6. Solar active envelope module with an adjustable transmittance/absorptance

    Directory of Open Access Journals (Sweden)

    C. Villasante Villasante

    2015-06-01

    Full Text Available A solar active envelope module with a high flexibility degree is proposed in this paper. The transparent module controls the day-lighting of the room, improving the indoor environment, while absorbing the superfluous solar energy inside. That energy is used to increase the efficiency of heating, ventilation, and the air-conditioning (HVAC system of the building. This is carried out through a fine control of the absorptance of the envelope module. The active envelope module consists of three glazed chambers with advanced coatings and frames to assure a minimum thermal transmittance while allowing transparency. A fluid containing heat-absorbing nanoparticles flows inside the central chamber and is heated up due to the impinging solar energy. Unlike other systems proposed in the past, which included transparency control systems based on complex filters and chemical processes, the absorption of the module is controlled by the variation of the thickness of the central chamber with a mechanical device. That is, varying the thickness of the central chamber, it allows controlling the absorptance of the whole system and, as a result, indoor day-lighting and thermal loads. Therefore, a new system is proposed that enables to:  

  7. Thermoeconomic comparison of industrial heat pumps

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Christen Malte; Reinholdt, L.

    2011-01-01

    , limitations and design, a generic comparison is used. To establish the optimal individual temperature range of operation, a thermoeconomic evaluation is performed, with heat price as the decision parameter. Each individual heat pump is favourable in specific temperature intervals, which will vary according......Four natural working fluids in various heat pump cycles are expected to cover the heating range between 50oC and 150°C. The different thermodynamic cycles are the Condensing Vapour, Transcritical and Compression/Absorption. As the considered technologies have significant differences in application...... to the temperature lift between sink and source. At temperature lifts below 30°C the entire temperature range is covered. Exceeding this temperature lift, the range of sink temperatures is not completely covered above 125°C. Three of the heat pumps prove very cost competitive when compared to heating with natural...

  8. Absorption refrigeration cycle applied to offshore platforms; Refrigeracao por absorcao aplicada a plataformas de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Maximino Joaquim Pina [KROMAV Engenharia, Rio de Janeiro, RJ (Brazil); Pinto, Luiz Antonio Vaz; Belchior, Carlos Rodrigues Pereira [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)

    2004-07-01

    To produce cold from the heat seems a task unlikely or even impossible. However, absorption systems produce cooling from heat sources and it exist since the century XIX. In industrial places is very important to improve the energy use, even more in places where the activities involve great costs and incomes. Traditionally the alternatives conflict in the aspects of initial and operational costs. This paper describes the absorption systems operation and its main advantages and disadvantages, when compared to the traditional systems with compressor. The known fact that a vapor compressor system presents larger efficiency is not enough to validate it for all of the applications. In this sense, the initial and operational analysis of the costs of the absorption systems becomes interesting. In spite of, double effect absorption systems are demonstrating the evolution of the absorption cycle in order to obtain better performance. Turbo-generators and Turbo-compressors of the offshore platforms are thermal machines that reject great amount of heat in the exhaust gases. This heat is used for heating of water used in the Process Plant. The processes of separation of the mixture water-oil-gas from the well, for instance, use that heat. Even after the passage of the water in the Plant of Process, the residual heat is still enough for the use in absorption systems. A simulation is done using real data of an offshore platform. Two possible alternatives are compared under technical and economical aspects. Sensibility analysis is also performed in order to verify possible impacts of variations of electric power cost. (author)

  9. Characterization of hydrophobic nanoporous particle liquids for energy absorption

    Science.gov (United States)

    Hsu, Yi; Liu, Yingtao

    2016-04-01

    Recently, the development of hydrophobic nanoporous technologies has drawn increased attention, especially for the applications of energy absorption and impact protection. Although significant amount of research has been conducted to synthesis and characterize materials to protect structures from impact damage, the tradition methods focused on converting kinetic energy to other forms, such as heat and cell buckling. Due to their high energy absorption efficiency, hydrophobic nanoporous particle liquids (NPLs) are one of the most attractive impact mitigation materials. During impact, such particles directly trap liquid molecules inside the non-wetting surface of nanopores in the particles. The captured impact energy is simply stored temporarily and isolated from the original energy transmission path. In this paper we will investigate the energy absorption efficiency of combinations of silica nanoporous particles and with multiple liquids. Inorganic particles, such as nanoporous silica, are characterized using scanning electron microscopy. Small molecule promoters, such as methanol and ethanol, are introduced to the prepared NPLs. Their effects on the energy absorption efficiency are studied in this paper. NPLs are prepared by dispersing the studied materials in deionized water. Energy absorption efficiency of these liquids are experimentally characterized using an Instron mechanical testing frame and in-house develop stainless steel hydraulic cylinder system.

  10. Heat convection

    Energy Technology Data Exchange (ETDEWEB)

    Jiji, L.M. [City Univ. of New York, NY (United States). Dept. of Mechanical Engineering

    2006-07-01

    Professor Jiji's broad teaching experience lead him to select the topics for this book to provide a firm foundation for convection heat transfer with emphasis on fundamentals, physical phenomena, and mathematical modelling of a wide range of engineering applications. Reflecting recent developments, this textbook is the first to include an introduction to the challenging topic of microchannels. The strong pedagogic potential of Heat Convection is enhanced by the following ancillary materials: (1) Power Point lectures, (2) Problem Solutions, (3) Homework Facilitator, and, (4) Summary of Sections and Chapters. (orig.)

  11. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... for signs of heat stroke or exhaustion. Heat Stroke and Exhaustion Symptoms of early heat exhaustion symptoms ... heavy sweating; nausea; and giddiness. Symptoms of heat stroke (late stage of heat illness) include flushed, hot, ...

  12. Renewable Heating and Cooling

    Science.gov (United States)

    Renewable heating and cooling is a set of alternative resources and technologies that can be used in place of conventional heating and cooling technologies for common applications such as water heating, space heating, space cooling and process heat.

  13. Absorption and Metabolism of Xanthophylls

    Directory of Open Access Journals (Sweden)

    Eiichi Kotake-Nara

    2011-06-01

    Full Text Available Dietary carotenoids, especially xanthophylls, have attracted significant attention because of their characteristic biological activities, including anti-allergic, anti-cancer, and anti-obese actions. Although no less than forty carotenoids are ingested under usual dietary habits, only six carotenoids and their metabolites have been found in human tissues, suggesting selectivity in the intestinal absorption of carotenoids. Recently, facilitated diffusion in addition to simple diffusion has been reported to mediate the intestinal absorption of carotenoids in mammals. The selective absorption of carotenoids may be caused by uptake to the intestinal epithelia by the facilitated diffusion and an unknown excretion to intestinal lumen. It is well known that β-carotene can be metabolized to vitamin A after intestinal absorption of carotenoids, but little is known about the metabolic transformation of non provitamin A xanthophylls. The enzymatic oxidation of the secondary hydroxyl group leading to keto-carotenoids would occur as a common pathway of xanthophyll metabolism in mammals. This paper reviews the absorption and metabolism of xanthophylls by introducing recent advances in this field.

  14. MULTIFUNCTIONAL SOLAR SYSTEMS FOR HEATING AND COOLING

    Directory of Open Access Journals (Sweden)

    Doroshenko A.V.

    2010-12-01

    Full Text Available The basic circuits of multifunctional solar systems of air drainage, heating (hot water supply and heating, cooling and air conditioning are developed on the basis of open absorption cycle with a direct absorbent regeneration. Basic decisions for new generation of gas-liquid solar collectors are developed. Heat-mass-transfer apparatus included in evaporative cooling system, are based on film interaction of flows of gas and liquid and in them, for the creation of nozzle, multi-channel structures from polymeric materials and porous ceramics are used. Preliminary analysis of multifunctional systems possibilities is implemented.

  15. Infrared heating

    Science.gov (United States)

    IR heating was first industrially used in the 1930s for automotive curing applications and rapidly became a widely applied technology in the manufacturing industry. Contrarily, a slower pace in the development of IR technologies for processing foods and agricultural products was observed, due to lim...

  16. Cost reductions in absorption chillers. Final report, June 1984-May 1985

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, R.W.

    1986-05-01

    Absorption chillers have great difficulty competing with the electric-driven compression alternative, due in part to modest operating efficiencies and largely to high first costs. This project is an assessment of the possibility of lowering the costs of absorption chillers dramatically by the use of low material intensity in the design of a new generation of these machines. Breakeven costs for absorption chillers, their heat exchangers and heat exchanger materials were established which will allow commercial success. Polymeric and metallic materials appropriate to particular components and which meet the cost goals were identified. A subset of these materials were tested and ordered by success in tolerating conditions and materials found in absorption chiller applications. Conceptual designs which indicate the practicality of the low material intensity approach were developed. The work reported here indicates that there is a high probability that this apporach will be successful.

  17. Numerical simulation on vapor absorption by wavy lithium bromide aqueous solution films

    Science.gov (United States)

    Bo, Shoushi; Ma, Xuehu; Chen, Hongxia; Lan, Zhong

    2011-12-01

    Numerical simulation has been made on heat and mass transfer of vapor absorption by wavy lithium bromide aqueous solution films. The velocity fields and interface positions are obtained by VOF model. Solitary waves are generated by periodically disturbed inflow boundary. Based on these, the temperature and concentration fields are obtained with a stationary interface shape. The effect of solitary waves on the heat and mass transfer across the film is investigated. It is shown that due to the mixing of circulation and stretch of large film thickness, the gradient of concentration and absorption rate decrease for solitary wave region. The region of capillary waves shows a significant amount of absorption enhancement. The percentage of absorption for the different regions is quantified.

  18. On the Heat Transfer through a Solid Slab Heated Uniformly and Continuously on One of Its Surfaces

    Science.gov (United States)

    Marin, E.; Lara-Bernal, A.; Calderon, A.; Delgado-Vasallo, O.

    2011-01-01

    Some peculiarities of the heat transfer through a sample that is heated by the superficial absorption of light energy under continuous uniform illumination are discussed. We explain, using a different approach to that presented in a recent article published in this journal (Salazar "et al" 2010 "Eur. J. Phys." 31 1053-9), that the front surface of…

  19. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel

    2005-01-01

    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...... patterns. It can approach 100% as closely as desired, although in practice this may not be an attractive solution. An example with a small endfire array of dipoles shows an efficiency of 93%. Several examples of small conical horn antennas are also given, and they all have absorption efficiencies less than...

  20. Nonlinear absorption in discrete systems

    Energy Technology Data Exchange (ETDEWEB)

    Spire, A; Leon, J [Physique Mathematique et Theorique, CNRS-UMR5825, Universite Montpellier 2, 34095 Montpellier (France)

    2004-10-01

    In the context of nonlinear scattering, a continuous wave incident onto a nonlinear discrete molecular chain of coupled oscillators can be partially absorbed as a result of a three-wave resonant interaction that couples two HF-waves of frequencies close to the edge of the Brillouin zone. Hence both nonlinearity and discreteness are necessary for generating this new absorption process which manifests itself by soliton generation in the medium. As a paradigm of this nonlinear absorption we consider here the Davydov model that describes exciton-phonon coupling in hydrogen-bonded molecular chains.

  1. A second law analysis and entropy generation minimization of an absorption chiller

    KAUST Repository

    Myat, Aung

    2011-10-01

    This paper presents performance analysis of absorption refrigeration system (ARS) using an entropy generation analysis. A numerical model predicts the performance of absorption cycle operating under transient conditions along with the entropy generation computation at assorted heat source temperatures, and it captures also the dynamic changes of lithium bromide solution properties such as concentration, density, vapor pressure and overall heat transfer coefficients. An optimization tool, namely the genetic algorithm (GA), is used as to locate the system minima for all defined domain of heat source and cooling water temperatures. The analysis shows that minimization of entropy generation the in absorption cycle leads to the maximization of the COP. © 2011 Elsevier Ltd. All rights reserved.

  2. Water absorption and retention of porous ceramics fabricated by waste resources

    OpenAIRE

    Tomoaki, KATO; Masayoshi, Ohashi; Masayoshi, Fuji; Minoru, Takahashi

    2008-01-01

    Several counter measures have been carried out for mitigating heat island effect. One of those is installing on top of the roof with base materials having planted vegetation. The base materials are required good water absorption and retention which is necessary for the plant to survive. Therefore, in this study, we investigate the relationship between water absorption and water retention within the pore structures of porous ceramics. The raw materials of the ceramics were used waste resources...

  3. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  4. Heat pump

    OpenAIRE

    Klíma, Martin

    2010-01-01

    Bakalářská práce popisuje a charakterizuje tepelné čerpadlo. Obsahuje souhrn jednotlivých druhů tepelných čerpadel z hlediska získávání energie, princip jejich funkce a popis odlišností mezi jednotlivými druhy kompresorů, použití pracovní látky a její vývin do budoucna. Závěrem je zde uveden můj vlastní názor na tepelné čerpadlo, které bych preferoval. Bachelor thesis describes and characterizes the heat pump. Summarizes the various types of heat pumps in terms of energy production, princi...

  5. Low-Absorption Laser Windows

    Science.gov (United States)

    1976-04-01

    ABSORPTION MEASUREMENTS AT 1.06 Urn James W. Davisson U.S. Naval Research Laboratory Washington, D.C. 20375 ABSTRACT A procedure for the chemical poli...W. Davisson , Fourth Laser Window Materials Conf. p. 466). The alkaline earth fluorides and LiF were mechanically polished by rubbing: till dry

  6. Theory of graphene saturable absorption

    Science.gov (United States)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  7. Heat Exchange

    OpenAIRE

    Bottomley, Stephen

    2012-01-01

    Heat Exchange’ is an international touring exhibition of enamel metalwork curated by Turrell.E (UK), Gegenwart (Germany/UK) and Cameron (Australia). Bottomley was one of twenty-three international artists invited to join a transcontinental on-line blog and forum that recorded individual contemporary approaches to working with vitreous enamel the year prior to the 2012 exhibition that coincided with the SNAG (Society of North American Goldsmiths) National Conference in Phoenix Arizona USA.Vitr...

  8. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier

    2007-10-01

    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from −0.79 to −0.53 W m−2 (33% and all-sky from −0.47 to −0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  9. Absorptive capacity and smart companies

    Directory of Open Access Journals (Sweden)

    Patricia Moro González

    2014-12-01

    Full Text Available Purpose: The current competitive environment is substantially modifying the organizations’ learning processes due to a global increase of available information allowing this to be transformed into knowledge. This opportunity has been exploited since the nineties by the tools of “Business Analytics” and “Business Intelligence” but, nevertheless, being integrated in the study of new organizational capacities engaged in the process of creating intelligence inside organizations is still an outstanding task. The review of the concept of absorptive capacity and a detailed study from the perspective of this new reality will be the main objective of study of this paper.Design/methodology/approach: By comparing classical absorptive capacity and absorptive capacity from the point of view of information management tools in each one of the three stages of the organizational learning cycle, some gaps of the former are overcome/fulfilled. The academic/bibliographical references provided in this paper have been obtained from ISI web of knowledge, Scopus and Dialnet data bases, supporting the state of affairs on absorptive capacity and thereafter filtering by "Business Intelligence" and "Business Analytics". Specialized websites and Business Schools` Publications there have also been included, crowning the content on information management tools used that are currently used in the strategic consulting.Findings: Our contribution to the literature is the development of "smart absorptive capacity". This is a new capacity emerging from the reformulation of the classical concept of absorptive capacity wherein some aspects of its definition that might have been omitted are emphasized. The result of this new approach is the creation of a new Theoretical Model of Organizational Intelligence, which aims to explain, within the framework of the Resources and Capabilities Theory, the competitive advantage achieved by the so-called smart companies

  10. Cost Price of Products in the System of Heat, Refrigeration and Electric Energy Production Combined at Thermal Power Plant

    OpenAIRE

    Tubolev Alexander; Romashova Olga; Belyaev Leonid

    2016-01-01

    Nowadays combination of electric, heat and refrigerating energy production (trigeneration) is one of the modern technological solutions for energy efficiency increase and ecological problem solution [1]. Two types of refrigerating machines can be used for both energy and heat production combined: compression aggregates consuming electric energy and absorption aggregates using hot water heat, vapor or other heat conductors.

  11. LiBr absorption systems integrated with high–efficiency IGSG plant

    DEFF Research Database (Denmark)

    Rokni, Masoud; Bellomare, Filippo

    2015-01-01

    Over the last few years, the energy demand for cooling systems is increasing; different solutions in fact have been proposed in order to minimize the energetic and environmental impact of this trend. In this direction, absorption cooling systems are recognized as a valid alternative to traditional...... vapor compression inverse cycles; waste heat from other systems can in fact be used as an efficient input instead of electrical energy. The opportunity to integrate Li-Br absorption systems with a high-efficiency energy plant was studied; rejected heat from a Municipal Solid Waste Gasification Plant...

  12. Heat pump system

    Science.gov (United States)

    Swenson, Paul F.; Moore, Paul B.

    1979-01-01

    An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchangers and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

  13. Solar-powered absorption refrigeration system; Solarbetriebene Absorptions-Kaeltemaschine MGB - Zuerich

    Energy Technology Data Exchange (ETDEWEB)

    Corbaz, C.; Utz, C.

    2005-07-01

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) reviews the project implemented at the head offices of the Migros co-operative society MGB in Zurich, Switzerland, involving cold generation using evacuated solar collectors and an absorption refrigeration system. The experience gained with this first solar powered cooling system using evacuated tube collectors located on the flat roof of the building is discussed. Considerable possibilities for the optimisation of the system are discussed, including the use of excess heat stored overnight in the warm-up phase of operation on the next day. The advantages of the correct placing of equipment rooms near to collectors and cooling-towers are discussed. The operation and characteristics of the installation in winter and summer operation are briefly described and figures on its performance and the costs involved are quoted.

  14. Two-dimensional thermometry by using neutron resonance absorption spectrometer DOG

    Energy Technology Data Exchange (ETDEWEB)

    Kamiyama, T.; Noda, H.; Kiyanagi, Y. [Department of Quantum Energy Engineering, Graduate School of Engineering, Hokkaido Univ., Sapporo (Japan); Ikeda, S. [Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    2001-03-01

    We applied the neutron resonance absorption spectroscopy to thermometry of a bulk object. The measurement was done by using the neutron resonance absorption spectrometer, DOG, installed at KENS, High Energy Accelerator Research Organization Neutron Source, which enables us to investigate effective temperature of a particular element by analyzing line width of resonance absorption spectrum. The effective temperature becomes consistence with the sample temperature above room temperature. For the analysis we applied the computed tomography method to reconstruct the temperature distribution on the object cross section. The results and the calculated distribution by the heat conducting equation are well agreed on the temperature difference inside the object. (author)

  15. Heat-Exchanger/Heat-Pipe Interface

    Science.gov (United States)

    Snyder, H. J.; Van Hagan, T. H.

    1987-01-01

    Monolithic assembly reliable and light in weight. Heat exchanger and evaporator ends of heat pipes integrated in monolithic halves welded together. Interface assembly connects heat exchanger of furnace, reactor, or other power source with heat pipes carrying heat to radiator or power-consuming system. One of several concepts proposed for nuclear power supplies aboard spacecraft, interface useful on Earth in solar thermal power systems, heat engines, and lightweight cooling systems.

  16. Controllable generation and manipulation of micro-bubbles in water with absorptive colloid particles by CW laser radiation

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya.; Maksimyak, P. P.

    2017-01-01

    Micrometer-sized vapor-gas bubbles are formed due to local heating of a water suspension containing absorptive pigment particles of 100 nm diameter. The heating is performed by CW near-infrared (980 nm) laser radiation with controllable power, focused into a 100 mu m spot within a 2 mm suspension...

  17. Thermodynamic modeling of CO2 absorption in aqueous N-Methyldiethanolamine using Extended UNIQUAC model

    DEFF Research Database (Denmark)

    Sadegh, Negar; Stenby, Erling Halfdan; Thomsen, Kaj

    2015-01-01

    of pure MDEA vapor pressure, vapor-liquid equilibrium (VLE) (total pressure and CO2 partial pressure), freezing point depression (SLE), excess enthalpy, heat capacity and heat of absorption were used to adjust model parameters. The model was then used to predict the NMR spectroscopic data. The developed...

  18. Heating systems for heating subsurface formations

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  19. Hydride heat pump with heat regenerator

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative hydride heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system. A series of at least four canisters containing a lower temperature performing hydride and a series of at least four canisters containing a higher temperature performing hydride is provided. Each canister contains a heat conductive passageway through which a heat transfer fluid is circulated so that sensible heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  20. Near-perfect broadband absorption from hyperbolic metamaterial nanoparticles

    Science.gov (United States)

    Riley, Conor T.; Smalley, Joseph S. T.; Brodie, Jeffrey R. J.; Fainman, Yeshaiahu; Sirbuly, Donald J.; Liu, Zhaowei

    2017-02-01

    Broadband absorbers are essential components of many light detection, energy harvesting, and camouflage schemes. Current designs are either bulky or use planar films that cause problems in cracking and delamination during flexing or heating. In addition, transferring planar materials to flexible, thin, or low-cost substrates poses a significant challenge. On the other hand, particle-based materials are highly flexible and can be transferred and assembled onto a more desirable substrate but have not shown high performance as an absorber in a standalone system. Here, we introduce a class of particle absorbers called transferable hyperbolic metamaterial particles (THMMP) that display selective, omnidirectional, tunable, broadband absorption when closely packed. This is demonstrated with vertically aligned hyperbolic nanotube (HNT) arrays composed of alternating layers of aluminum-doped zinc oxide and zinc oxide. The broadband absorption measures >87% from 1,200 nm to over 2,200 nm with a maximum absorption of 98.1% at 1,550 nm and remains large for high angles. Furthermore, we show the advantages of particle-based absorbers by transferring the HNTs to a polymer substrate that shows excellent mechanical flexibility and visible transparency while maintaining near-perfect absorption in the telecommunications region. In addition, other material systems and geometries are proposed for a wider range of applications.

  1. Simulation of solar-powered absorption cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Atmaca, I.; Yigit, A. [Uludag Univ., Bursa (Turkey). Dept. of Mechanical Engineering

    2003-07-01

    With developing technology and the rapid increase in world population, the demand for energy is ever increasing. Conventional energy will not be enough to meet the continuously increasing need for energy in the future. In this case, renewable energy sources will become important. Solar energy is a very important energy source because of its advantages. Instead of a compressor system, which uses electricity, an absorption cooling system, using renewable energy and kinds of waste heat energy, may be used for cooling. In this study, a solar-powered, single stage, absorption cooling system, using a water-lithium bromide solution, is simulated. A modular computer program has been developed for the absorption system to simulate various cycle configurations and solar energy parameters for Antalya, Turkey. So, the effects of hot water inlet temperatures on the coefficient of performance (COP) and the surface area of the absorption cooling components are studied. In addition, reference temperatures which are the minimum allowable hot water inlet temperatures are determined and their effect on the fraction of the total load met by non-purchased energy (FNP) and the coefficient of performance are researched. Also, the effects of the collector type and storage tank mass are investigated in detail. (author)

  2. Effects of particle size and laser wavelength on heating of silver ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 87; Issue 2. Effects of ... Nanoparticles, pulsed laser, heating, absorbance. Abstract. Laser energy absorption results in significant heating of metallic nanoparticles and controlling the heating of nanoparticles is one of the essential stages of selective cell targeting.

  3. Køling ved hjælp af fjernvarme (Using District Heating for Cooling)

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard

    1999-01-01

    The theoretical basic using heat to produce cooling is explained by combining two Carnot processes. Ejector and Absoption cycles, which are two pratical processe using heat, are explained. For absorption cycles different layout is shown using low temperature heat source. It is shown how a high...

  4. Review Article: Heat stress and the role of protective clothing in ...

    African Journals Online (AJOL)

    Background: The body heat exchange, environmental stress and protective clothing becomes stressful in military service too. The use of microporous material and ventilation of garment significantly improve heat exchange, hence reducing physiological strain and improving tolerance to the heat. Moisture absorption ...

  5. Heat pipes

    CERN Document Server

    Dunn, Peter D

    1982-01-01

    A comprehensive, up-to-date coverage of the theory, design and manufacture of heat pipes and their applications. This latest edition has been thoroughly revised, up-dated and expanded to give an in-depth coverage of the new developments in the field. Significant new material has been added to all the chapters and the applications section has been totally rewritten to ensure that topical and important applications are appropriately emphasised. The bibliography has been considerably enlarged to incorporate much valuable new information. Thus readers of the previous edition, which has established

  6. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Emergencies A-Z Share this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at ... about heat cramps and heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the ...

  7. Low temperature nuclear heat

    Energy Technology Data Exchange (ETDEWEB)

    Kotakorpi, J.; Tarjanne, R. (comps.)

    1977-08-01

    The meeting was concerned with the use of low grade nuclear heat for district heating, desalination, process heat, and agriculture and aquaculture. The sessions covered applications and demand, heat sources, and economics.

  8. Regenerative Hydride Heat Pump

    Science.gov (United States)

    Jones, Jack A.

    1992-01-01

    Hydride heat pump features regenerative heating and single circulation loop. Counterflow heat exchangers accommodate different temperatures of FeTi and LaNi4.7Al0.3 subloops. Heating scheme increases efficiency.

  9. Approach for an improved experimental evaluation of the specific absorption rate in magnetic fluid hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Iacob, N. [National Institute for Lasers, Plasma and Radiation Physics (Romania); Schinteie, G.; Palade, P.; Kuncser, V., E-mail: kuncser@infim.ro [National Institute of Materials Physics (Romania)

    2015-04-15

    A new methodology for the accurate determination of the specific absorption rate of ferrofluids with magnetite nanoparticles of average size of about 10 nm subjected to alternative current magnetic fields is proposed. A simple numerical compensation of the heating rates by the cooling rates obtained at similar temperatures is employed. Comparisons of the as-obtained adiabatic heating curves with theoretical evaluations are discussed.

  10. Thermodynamic Analysis of the Irreversibilities in Solar Absorption Refrigerators

    Directory of Open Access Journals (Sweden)

    Emma Berrich Betouche

    2016-03-01

    Full Text Available A thermodynamic analysis of the irreversibility on solar absorption refrigerators is presented. Under the hierarchical decomposition and the hypothesis of an endoreversible model, many functional and practical domains are defined. The effect of external heat source temperature on the entropy rate and on the inverse specific cooling load (ISCL multiplied by the total area of the refrigerator A/Qe are studied. This may help a constructor to well dimension the solar machine under an optimal technico-economical criterion A/Qe and with reasonable irreversibility on the refrigerator. The solar concentrator temperature effect on the total exchanged area, on the technico-economical ratio A/Qe, and on the internal entropy rate are illustrated and discussed. The originality of these results is that they allow a conceptual study of a solar absorption refrigeration cycle.

  11. Brownian rotational relaxation and power absorption in magnetite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Goya, G.F. [Institute of Nanoscience of Aragon (INA), University of Zaragoza, 50009 Zaragoza (Spain)]. E-mail: goya@unizar.es; Fernandez-Pacheco, R. [Institute of Nanoscience of Aragon (INA), University of Zaragoza, 50009 Zaragoza (Spain); Arruebo, M. [Institute of Nanoscience of Aragon (INA), University of Zaragoza, 50009 Zaragoza (Spain); Cassinelli, N. [Electronics Division, Bauer and Associates, Buenos Aires (Argentina); Facultad de Ingenieria, UNLP (Argentina); Ibarra, M.R. [Institute of Nanoscience of Aragon (INA), University of Zaragoza, 50009 Zaragoza (Spain)

    2007-09-15

    We present a study of the power absorption efficiency in several magnetite-based colloids, to asses their potential as magnetic inductive hyperthermia (MIH) agents. Relaxation times {tau} were measured through the imaginary susceptibility component {chi}{sup '}'(T), and analyzed within Debye's theory of dipolar fluid. The results indicated Brownian rotational relaxation and allowed to calculate the hydrodynamic radius close to the values obtained from photon correlation. The study of the colloid performances as power absorbers showed no detectable increase of temperature for dextran-coated Fe{sub 3}O{sub 4} nanoparticles, whereas a second Fe{sub 3}O{sub 4}-based dispersion of similar concentration could be heated up to 12K after 30min under similar experimental conditions. The different power absorption efficiencies are discussed in terms of the magnetic structure of the nanoparticles.

  12. A mid-infrared absorption diagnostic for acetylene detection

    KAUST Repository

    KC, Utsav

    2015-05-14

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm−1 over a wide range of temperatures (1000–2200 K) and pressures (1–5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene. © 2015 Springer-Verlag Berlin Heidelberg

  13. Carotenoid absorption in chicken intestine.

    Science.gov (United States)

    Gómez, R; Alonso, A; Martín, M

    1978-09-01

    The powdered flowers of marigold (Tagetes erecta) are used as a cheap source of carotenoids in avicultura. Lutein (3,3'-dyhydroxi-alpha-carotene) constitutes up to 85 to 90% of marigold carotenoids. In the plant, lutein is found esterified to palmitic or estearic acid. In chicken, carotenoid is hydrolized in the first portion of the small intestine, and absorbed as free lutein. After the absorption, lutein is not re-esterified in the different chicken tissues.

  14. Geometrical interpretation of optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Monzon, J. J.; Barriuso, A. G.; Sanchez-Soto, L. L. [Departamento de Optica, Facultad de Fisica, Universidad Complutense, E-28040 Madrid (Spain); Montesinos-Amilibia, J. M. [Departamento de Geometria y Topologia, Facultad de Matematicas, Universidad Complutense, E-28040 Madrid (Spain)

    2011-08-15

    We reinterpret the transfer matrix for an absorbing system in very simple geometrical terms. In appropriate variables, the system appears as performing a Lorentz transformation in a (1 + 3)-dimensional space. Using homogeneous coordinates, we map that action on the unit sphere, which is at the realm of the Klein model of hyperbolic geometry. The effects of absorption appear then as a loxodromic transformation, that is, a rhumb line crossing all the meridians at the same angle.

  15. On the nature of absorption

    CERN Document Server

    Barger, V; Halzen, F

    1972-01-01

    The imaginary helicity non-flip omega exchange amplitudes in KN and NN scattering are determined versus t and s from data on elastic differential cross section differences. The omega -universality prediction Im omega /sub N/(t)= 3 Im omega /sub K/(t), is found to be satisfied for 0absorptive cuts as small t preserve universality. The impact parameter distributions of the omega amplitudes show: (i) a peripheral peak centred around b approximately=1 fm, with Delta b approximately =+or-0.5 fm in KN and Delta b approximately=+or-0.75 fm in NN; (ii) a sizeable negative contribution at small b, more negative in NN than in KN, (iii) a smaller tail of negative contributions around b approximately=2 fm. Strong absorption of the omega -pole imaginary amplitude with lambda values around two is needed to reproduced this structure. A new version of the absorption model suggested by pi N amplitude analysis, is confirmed by the results. (20 refs).

  16. Topical absorption and systemic toxicity.

    Science.gov (United States)

    Alikhan, Fatima Sasha; Maibach, Howard

    2011-09-01

    Dermal absorption of some chemicals and drugs can cause systemic toxicity. We evaluated several case reports from the past decade, which discuss the dermal absorption of a specific chemical and potential local and systemic effects. We focused on herbicide and pesticide exposure along with exposure to cutaneous medication, occupational contact, and cosmeceutical exposure. Although causality cannot be established in most cases, it is critical to be aware of the possible effects of topical absorption that may not be immediately apparent. We recommended further studies on specific chemicals to ascertain causality and determine the highest exposure level with no observed adverse affect level (NOAEL) and the reference dose (RfD). Post-marketing epidemiology data in most geographical areas are markedly limited. A weak link in public health resides in the inadequate reporting and workup of alleged chemically related adverse effects. This arena mandates a re-thinking of how to increase this reporting, and workup, as a backup to our preclinical and clinical studies. Public awareness and funding will be rewarded by increased evidence to backup pre-approval pre-marketing studies.

  17. Organizational forms and knowledge absorption

    Directory of Open Access Journals (Sweden)

    Radovanović Nikola

    2016-01-01

    Full Text Available Managing the entire portion of knowledge in an organization is a challenging task. At the organizational level, there can be enormous quantities of unknown, poorly valued or inefficiently applied knowledge. This is normally followed with the underdeveloped potential or inability of organizations to absorb knowledge from external sources. Facilitation of the efficient internal flow of knowledge within the established communication network may positively affect organizational capacity to absorb or identify, share and subsequently apply knowledge to commercial ends. Based on the evidences that the adoption of different organizational forms affects knowledge flows within an organization, this research analyzed the relationship between common organizational forms and absorptive capacity of organizations. In this paper, we test the hypothesis stating that the organizational structure affects knowledge absorption and exploitation in the organization. The methodology included quantitative and qualitative research method based on a questionnaire, while the data has been statistically analyzed and the hypothesis has been tested with the use of cross-tabulation and chi-square tests. The findings suggest that the type of organizational form affects knowledge absorption capacity and that having a less formalized and more flexible structure in an organization increases absorbing and exploiting opportunities of potentially valuable knowledge.

  18. Segmented heat exchanger

    Science.gov (United States)

    Baldwin, Darryl Dean; Willi, Martin Leo; Fiveland, Scott Byron; Timmons, Kristine Ann

    2010-12-14

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  19. Dual source heat pump

    Science.gov (United States)

    Ecker, Amir L.; Pietsch, Joseph A.

    1982-01-01

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

  20. Ion Bernstein wave heating research

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Masayuki.

    1992-03-01

    Ion Bernstein wave heating (IBWH) utilizes the ion Bernstein wave (IBW), a hot plasma wave, to carry the radio frequency (rf) power to heat tokamak reactor core. Earlier wave accessibility studies have shown that this finite-Larmor-radius (FLR) mode should penetrate into a hot dense reactor plasma core without significant attenuation. Moreover, the IBW's low phase velocity ({omega}/k{sub {perpendicular}} {approx} V{sub Ti} {much lt} V{sub {alpha}}) greatly reduces the otherwise serious wave absorption by the 3.5 MeV fusion {alpha}-particles. In addition, the property of IBW's that k{sub {perpendicular}} {rho}{sub i} {approx} 1 makes localized bulk ion heating possible at the ion cyclotron harmonic layers. Such bulk ion heating can prove useful in optimizing fusion reactivity. In another vein, with proper selection of parameters, IBW's can be made subject to strong localized electron Landau damping near the major ion cyclotron harmonic resonance layers. This property can be useful, for example, for rf current drive in the reactor plasma core. This paper discusses this research.

  1. Ion Bernstein wave heating research

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Masayuki

    1992-03-01

    Ion Bernstein wave heating (IBWH) utilizes the ion Bernstein wave (IBW), a hot plasma wave, to carry the radio frequency (rf) power to heat tokamak reactor core. Earlier wave accessibility studies have shown that this finite-Larmor-radius (FLR) mode should penetrate into a hot dense reactor plasma core without significant attenuation. Moreover, the IBW`s low phase velocity ({omega}/k{sub {perpendicular}} {approx} V{sub Ti} {much_lt} V{sub {alpha}}) greatly reduces the otherwise serious wave absorption by the 3.5 MeV fusion {alpha}-particles. In addition, the property of IBW`s that k{sub {perpendicular}} {rho}{sub i} {approx} 1 makes localized bulk ion heating possible at the ion cyclotron harmonic layers. Such bulk ion heating can prove useful in optimizing fusion reactivity. In another vein, with proper selection of parameters, IBW`s can be made subject to strong localized electron Landau damping near the major ion cyclotron harmonic resonance layers. This property can be useful, for example, for rf current drive in the reactor plasma core. This paper discusses this research.

  2. Mechanistic Approaches to Predicting Oral Drug Absorption

    OpenAIRE

    Huang, Weili; Lee, Sau Lawrence; Yu, Lawrence X.

    2009-01-01

    Modeling and simulation of oral drug absorption have been widely used in drug discovery, development, and regulation. Predictive absorption models are used to determine the rate and extent of oral drug absorption, facilitate lead drug candidate selection, establish formulation development strategy, and support the development of regulatory policies. This review highlights the development of recent drug absorption models including dispersion and compartmental models. The compartmental models i...

  3. Emission and Absorption Entropy Generation in Semiconductors

    OpenAIRE

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika; Hansen, Ole

    2013-01-01

    While emission and absorption entropy generation is well known in black bodies, it has not previously been studied in semiconductors, even though semiconductors are widely used for solar light absorption in modern solar cells [1]. We present an analysis of the entropy generation in semiconductor materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconduc...

  4. Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

    Directory of Open Access Journals (Sweden)

    Marynowicz Andrzej

    2016-06-01

    Full Text Available The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples’ surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

  5. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    Energy Technology Data Exchange (ETDEWEB)

    Gary T. Rochelle; Eric Chen; J. Tim Cullinane; Marcus Hilliard; Babatunde Oyenekan; Terraun Jones

    2003-07-28

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. A rigorous thermodynamic model has been further developed with a standalone FORTRAN code to represent the CO{sub 2} vapor pressure and speciation of the new solvent. Gas chromatography has been used to measure the oxidative degradation of piperazine. The heat exchangers for the pilot plant have been received. The modifications are on schedule for start-up in November 2003.

  6. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    Energy Technology Data Exchange (ETDEWEB)

    Gary T. Rochelle; Eric Chen; J. Tim Cullinane; Marcus Hilliard; Terraun Jones

    2003-04-01

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. A rigorous thermodynamic model has been developed with a stand-alone FORTRAN code to represent the CO{sub 2} vapor pressure and speciation of the new solvent. Parameters have been developed for use of the electrolyte NRTL model in AspenPlus. Analytical methods have been developed using gas chromatography and ion chromatography. The heat exchangers for the pilot plant have been ordered.

  7. Numerically optimized band boundaries of Planck mean absorption coefficients in air plasma

    Science.gov (United States)

    Kloc, P.; Aubrecht, V.; Bartlova, M.

    2017-08-01

    Radiation heat transfer plays an important role in the energy balance of plasma in an electric arc and its accurate prediction is essential for the development of new electrical devices. Unfortunately, a very complex spectrum of the absorption coefficient makes accurate radiation heat transfer calculations a very challenging task, especially with complex geometries. Numerical approximation of the absorption coefficient is therefore commonly used to reduce computing demands. This paper presents our contribution to the topic of computing requirements reduction, namely the problem of frequency band selection for mean absorption coefficients (MACs). We show that, with the proper band distribution and averaging method, even a very low number of bands can be sufficient for an accurate approximation of the real radiation heat transfer. The band selection process is based upon numerical optimization with a mean value of each band being calculated as a line limited Planck MAC. Both the line limiting factor and associated characteristic plasma absorption length are investigated in detail and an optimal value equal to the three plasma radii is proposed. Tables for three bands mean absorption coefficients in air at the pressure of 1 bar and temperature range spanning from 300 K to 30 kK are included in this paper. These tables serve as input parameters for a fast evaluation of radiation transfer using either the P1 or discrete ordinates method (DOM) approximation with satisfactory accuracy.

  8. Avaliacão de programas de aquecimento para espectrometria de absorção atômica com atomizacão eletrotérmica em filamento de tungstênio Evaluation of heating programs for electrothermal atomic absorption spectrometry using a tungsten coil

    Directory of Open Access Journals (Sweden)

    Pedro V. Oliveira

    2000-10-01

    Full Text Available A tungsten coil atomizer was used to investigate the effect of heating programs with constant or variable drying temperatures on the atomization of Al, Cd, Cr and Pb. The variation of the surface temperature in the tungsten coil furnace can occur during each heating step due to the design of the power supply, that may apply constant voltages during a programmed time. For volatile elements (Cd, losses in sensitivity were observed when the program with a variable temperature was used. On the other hand, these effects are negligible for less volatile elements (Al and Cr and any tested program, in different acidic media, could be used without appreciable changes in sensitivities. The results allow the establishment of proper heating programs for elements with different thermochemical behavior in the tungsten coil atomizer.

  9. Absorption capacity and toxicity of paper points after sterilization

    Directory of Open Access Journals (Sweden)

    Mirian Marubayashi Hidalgo

    2008-01-01

    Full Text Available Objective: To evaluate the influence of the sterilization process on paper cones as regards their absorption capacity, and consequently, root canal drying, in addition to the possible release of any antimicrobial or cytotoxic product. Methods: The cones used were of three of the brands found on the Brazilian market Dentsply (Dentsply Indústria e Comércio Ltda., Petrópolis, Brazil, Endopoints (Endopoints Indústria e Comércio Ltda., Paraíba do Sul, Brazil and Tanari (Tanari Industrial Ltda., São Paulo, Brazil. To evaluate the absorption capacity, the cones were submitted to four sterilization cycles, and the modified Holland technique was performed. The antimicrobial/cytotoxic capacity was verified by means of depositing the sterilized cones in Petri dishes containing Miller-Hinton Agar and Blood Agar, seeded with S.aureus and E. coli. Results: The Dentsply (Dentsply Indústria e Comércio Ltda., Petrópolis, Brazil and Tanari (Tanari Industrial Ltda., São Paulo, Brazilcones presented greater absorption after the first sterilization cycle, followed by a drop in the second and third cycles, and a new increase in the fourth cycle. For the Endopoints (Endopoints Indústria e Comércio Ltda., Paraíba do Sul, Brazil cones, the values were inverted, with a small drop in absorption after the first cycle, increase in the second and third cycles, and a new drop in the fourth cycle. None of the cones presented antimicrobial activity after the sterilization process. Conclusion: The sterilization process by damp heat does not alter the properties of absorption and there is no release of by-products from the tested paper cones.

  10. Improvements to water vapor transmission and capillary absorption measurements in porous materials

    Science.gov (United States)

    Samuel L. Zelinka; Samuel V. Glass; Charles R. Boardman

    2016-01-01

    The vapor permeability (or equivalently the vapor diffusion resistance factor) and the capillary absorption coefficient are frequently used as inputs to hygrothermal or heat, air, and moisture (HAM) models. However, it has been well documented that the methods used to determine these properties are sensitive to the operator, and wide variations in the properties have...

  11. Influence of the laser-diode temperature on crystal absorption and ...

    Indian Academy of Sciences (India)

    Abstract. In this work, we studied the influence of heat loaded into the laser crystal in an end- pumped solid-state Nd:YVO4 high power laser. We have shown experimentally that the optimum value of the laser-diode temperature for the maximum pump power absorption by the Nd:YVO4 crystal and the maximum Nd:YVO4 ...

  12. Impacts of Aerosol Shortwave Radiation Absorption on the Dynamics of an Idealized Convective Atmospheric Boundary Layer

    NARCIS (Netherlands)

    Wilde Barbaro, E.; Vilà-Guerau de Arellano, J.; Krol, M.C.; Holtslag, A.A.M.

    2013-01-01

    We investigated the impact of aerosol heat absorption on convective atmospheric boundary-layer (CBL) dynamics. Numerical experiments using a large-eddy simulation model enabled us to study the changes in the structure of a dry and shearless CBL in depthequilibrium for different vertical profiles of

  13. In-situ soft X-ray absorption of over-exchanged Fe/ZSM5

    NARCIS (Netherlands)

    Heijboer, WM; Battiston, AA; Knop-Gericke, A; Havecker, M; Mayer, R; Bluhm, H; Schlogl, R; Weckhuysen, BM|info:eu-repo/dai/nl/285484397; Koningsberger, DC; de Groot, FMF|info:eu-repo/dai/nl/08747610X

    2003-01-01

    In-situ soft X-ray absorption spectroscopy (XAS) has been applied to study the iron redox behavior in over-exchanged Fe/ZSM5. The Fe L-2,L-3 XAS and O K spectral shapes of the Fe/ZSM5 surface have been measured during heat treatments and reduction/oxidation cycles. Charge-transfer multiplet

  14. Experimental study of negative temperatures in lithium-bromide absorption refrigerating machines

    Science.gov (United States)

    Stepanov, K. I.; Mukhin, D. G.; Alekseenko, S. V.; Volkova, O. V.

    2015-07-01

    The authors have developed a method and presented experimental data for obtaining negative temperatures of evaporation in lithium-bromide absorption chillers driven by heat recovery. It has been found that the attainable temperature of the refrigerated medium is the value of -5 °C.

  15. Integrated CO2, humidity and thermal control by membrane gas absorption

    NARCIS (Netherlands)

    Eckhard, F.; Feron, P.H.M.; Jacobs, P.; Savage, Ch.; Witt, J.

    1999-01-01

    In three consecutive studies the use of membrane gas absorption for the recovery of CO2, water vapour and heat has been studied by Stork and the TNO Institute of Environmental Sciences, Energy Research and Process Innovation. This work has financially been supported by ESA and the Dutch national

  16. Absorption Spectra Of Rbcl:Yb Rbbr:Yb And Rbi:Yb Crystals ...

    African Journals Online (AJOL)

    Single crystals of rubidium chloride, bromide and iodide were doped with substitutional divalent ytterbium, Yb ions, by heating them in ytterbium atmosphere. The absorption spectra of the Yb doped crystals were measured at room and liquid nitrogen temperatures. The spectra were found to consist of intense broad ...

  17. New thermodynamical systems. Alternative of compression-absorption; Nouveaux systemes thermodynamiques. Alternative de la compression-absorption

    Energy Technology Data Exchange (ETDEWEB)

    Feidt, M.; Brunin, O.; Lottin, O.; Vidal, J.F. [Universite Henri Poincare Nancy, 54 - Vandoeuvre-les-Nancy (France); Hivet, B. [Electricite de France, 77 - Moret sur Loing (France)

    1996-12-31

    This paper describes a 5 years joint research work carried out by Electricite de France (EdF) and the ESPE group of the LEMTA on compression-absorption heat pumps. It shows how a thermodynamical model of machinery, completed with precise exchanger-reactor models, allows to simulate and dimension (and eventually optimize) the system. A small power prototype has been tested and the first results are analyzed with the help of the models. A real scale experiment in industrial sites is expected in the future. (J.S.) 20 refs.

  18. Development and proof-testing of advanced absorption refrigeration cycle concepts

    Energy Technology Data Exchange (ETDEWEB)

    Modahl, R.J.; Hayes, F.C. (Trane Co., La Crosse, WI (United States). Applied Unitary/Refrigeration Systems Div.)

    1992-03-01

    The overall objectives of this project are to evaluate, develop, and proof-test advanced absorption refrigeration cycles that are applicable to residential and commercial heat pumps for space conditioning. The heat pump system is to be direct-fired with natural gas and is to use absorption working fluids whose properties are known. Target coefficients of performance (COPs) are 1.6 at 47{degrees}F and 1.2 at 17{degrees} in the heating mode, and 0.7 at 95{degree}F in the cooling mode, including the effect of flue losses. The project is divided into three phases. Phase I entailed the analytical evaluation of advanced cycles and included the selection of preferred concepts for further development. Phase II involves the development and testing of critical components and of a complete laboratory breadboard version of the selected system. Phase III calls for the development of a prototype unit and is contingent on the successful completion of Phase II. This report covers Phase I work on the project. In Phase 1, 24 advanced absorption cycle/fluid combinations were evaluated, and computer models were developed to predict system performance. COP, theoretical pump power, and internal heat exchange were calculated for each system, and these calculations were used as indicators of operating and installed costs in order to rank the relative promise of each system. The highest ranking systems involve the cycle concept of absorber/generator heat exchange, generator heat exchanger/absorber heat exchange, regeneration, and resorption/desorption, in combination with the NH{sub 3}/H{sub 2}O/LiBr ternary absorption fluid mixture or with the NH{sub 3}/H{sub 2}O binary solution. Based upon these conclusions, the recommendation was made to proceed to Phase II, the laboratory breadboard proof-of- concept.

  19. Nonazeotropic Heat Pump

    Science.gov (United States)

    Ealker, David H.; Deming, Glenn

    1991-01-01

    Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.

  20. Phytases for Improved Iron Absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Nyffenegger, Christian; Meyer, Anne S.

    2014-01-01

    Microbial phytases (EC 3.1.3.8) catalyse dephosphorylation of phytic acid, which is the primary storage compound for phosphorous in cereal kernels. The negatively charged phosphates in phytic acid chelate iron (Fe3+) and thus retards iron bioavailability in humans 1. Supplementation of microbial...... phytase can improve iron absorption from cereal-based diets 2. In order for phytase to catalyse iron release in vivo the phytase must be robust to low pH and proteolysis in the gastric ventricle. Our work has compared the robustness of five different microbial phytases, evaluating thermal stability...

  1. High heat flux single phase heat exchanger

    Science.gov (United States)

    Valenzuela, Javier A.; Izenson, Michael G.

    1990-01-01

    This paper presents the results obtained to date in a program to develop a high heat flux, single-phase heat exchanger for spacecraft thermal management. The intended application is a net generation interface heat exchanger to couple the crew module water thermal bus to the two-phase ammonia main thermal bus in the Space Station Freedom. The large size of the interface heat exchanger is dictated by the relatively poor water-side heat transfer characteristics. The objective of this program is to develop a single-phase heat transfer approach which can achieve heat fluxes and heat transfer coefficients comparable to those of the evaporation ammonia side. A new heat exchanger concept has been developed to meet these objecties. The main feature of this heat exchanger is that it can achieve very high heat fluxes with a pressure drop one to two orders of magnitude lower than those of previous microchannel or jet impingement high heat flux heat exchangers. This paper describes proof-of-concept experiments performed in air and water and presents analytical model of the heat exchanger.

  2. Solar heating cooling. Preparation of possible participation in IEA, Solar Heating Cooling Task 25; Solvarmedrevet koeling. Forberedelse af evt. deltagelse i IEA, Solar Heating Cooling Task 25

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    For the Danish solar heating industries it is interesting to discuss the domestic market possibilities and the export possibilities for solar heating cooling systems. The Danish solar heating sector also wants to participate in the international collaboration within IEA Solar Heating and Cooling Task 25 'Solar Assisted Air Conditioning of Buildings'. The Danish Energy Agency therefore has granted means for this project to discuss: The price of cooling for 3 different solar cooling methods (absorption cooling, desiccant cooling and ejector cooling); Market possibilities in Denmark and abroad; The advantages by Danish participation in IEA Task 25. The task has been solved through literature studies to establish status for the 3 technologies. It turned out that ejector cooling by low temperatures (85 deg. C from the solar collector) exists as pilot plants in relation to district heating, but is still not commercial accessible. Desiccant cooling, where the supplied heat has temperatures down to 55 deg. C is a well-developed technology. However only a handful of pilot plants with solar heating exists, and thus optimization relating to operation strategy and economy is on the experimental stage. Absorption cooling plants driven by solar heating are found in a large number in Japan and are also demonstrated in several other countries. The combination of absorption heating pump and solar heating is considered to be commercial accessible. Solar heating is interesting as heat source of to the exent that it can replace other sources of heat without the economy being depreciated. This can be the case in South Europe if: 1) oil or natural gas is used for heating; 2) a solar heating system already exists, e.g. for domestic water supply, and is installed so that the marginal costs by solar heating supply of the ventilation plant is reduced. All in all the above conditions mean that the market for solar heating for cooling is very limited in Europe, where almost

  3. Economic evaluation of geothermal power generation, heating, and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Kanoglu, Mehmet; Cengel, Yunus A. [Nevada Univ., Dept. of Mechanical Engineering, Reno, NV (United States)

    1999-06-01

    Economic analysis of a typical geothermal resource shows that potential revenues from geothermal heating or cooling can be much larger than those from power generation alone. Geothermal heating may generate up to about 3.1 times and geothermal absorption cooling 2.9 times as much revenue as power generation alone. Similarly, combined power generation and heating may generate about 2.1 times and combined power generation and cooling about 1.2 times as much revenue as power generation alone. Cost and payback period comparison appear to favor power generation, followed by district heating. (Author)

  4. [The Research for Trace Ammonia Escape Monitoring System Based on Tunable Diode Laser Absorption Spectroscopy].

    Science.gov (United States)

    Zhang, Li-fang; Wang, Fei; Yu, Li-bin; Yan, Jian-hua; Cen, Ke-fa

    2015-06-01

    In order to on-line measure the trace ammonia slip of the commercial power plant in the future, this research seeks to measure the trace ammonia by using tunable diode laser absorption spectroscopy under ambient temperature and pressure, and at different temperatures, and the measuring temperature is about 650 K in the power plant. In recent years lasers have become commercially available in the near-infrared where the transitions are much stronger, and ammonia's spectroscopy is pretty complicated and the overlapping lines are difficult to resolve. A group of ammonia transitions near 4 433.5 cm(-1) in the v2 +v3 combination band have been thoroughly selected for detecting lower concentration by analyzing its absorption characteristic and considering other absorption interference in combustion gases where H2O and CO2 mole fraction are very large. To illustrate the potential for NH3 concentration measurements, predictions for NH3, H2O and CO2 are simultaneously simulated, NH3 absorption lines near 4 433.5 cm(-1) wavelength meet weaker H2O absorption than the commercial NH3 lines, and there is almost no CO2 absorption, all the parameters are based on the HITRAN database, and an improved detection limit was obtained for interference-free NH3 monitoring, this 2.25 μm band has line strengths several times larger than absorption lines in the 1.53 μm band which was often used by NH3 sensors for emission monitoring and analyzing. The measurement system was developed with a new Herriott cell and a heated gas cell realizing fast absorption measurements of high resolution, and combined with direct absorption and wavelenguh modulation based on tunable diode laser absorption spectroscopy at different temperatures. The lorentzian line shape is dominant at ambient temperature and pressure, and the estimated detectivity is approximately 0.225 x 10(-6) (SNR = 1) for the directed absorption spectroscopy, assuming a noise-equivalent absorbance of 1 x 10(-4). The heated cell

  5. Absorption fluids data survey. [Planned data compilation for 25 refrigerant fluids and also mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S.

    1984-01-01

    The overall objective of this study is to develop improved data for the thermodynamic, transport and physical properties of absorption fluids. A specific objective of this phase of the study is to compile, catalog and coarse-screen the available US data of known absorption fluid systems and publish it as a first edition reference document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. This paper summarizes the methodology and findings of the compilation, cataloguing and coarse screening of the available US data on absorption fluid properties and presents current status and future work on this project. Both in-house-file and literature searches were undertaken to obtain available US publications with pertinent physical, thermodynamic and transport properties data for absorption fluids. Cross-checks of literature searches were also made, using available published bibliographies and literature review articles, to eliminate secondary sources for the data and include only original sources and manuscripts. The properties of these fluids relate to the liquid and/or vapor state, as encountered in normal operation of absorption equipment employing such fluids, and to the crystallization boundary of the liquid phase, where applicable. The actual data were systematically classified according to the type of fluid and property, as well as temperature, pressure and concentration ranges over which data were available. Data were sought for 14 different properties: Vapor-Liquid Equilibria, Crystallization Temperature, Corrosion Characteristics, Heat of Mixing, Liquid-Phase-Densities, Vapor-Liquid-Phase Enthalpies, Specific Heat, Stability, Viscosity, Mass Transfer Rate, Heat Transfer Rate, Thermal Conductivity, Flammability, and Toxicity. 67 refs.

  6. Iodine Absorption Cells Purity Testing

    Directory of Open Access Journals (Sweden)

    Jan Hrabina

    2017-01-01

    Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

  7. Circumgalactic Oxygen Absorption and Feedback

    Science.gov (United States)

    Mathews, William G.; Prochaska, J. Xavier

    2017-09-01

    O vi absorption in quasar spectra caused by intervening circumgalactic atmospheres suggests a downturn in the atmospheric column density in sightlines passing beyond about 100 kpc from central star-forming galaxies. This turnover supports the hypothesis that the oxygen originates in the central galaxies. When converted into oxygen space density using an Abel integral inversion, the O vi columns require ≳ {10}9 M ⊙ of oxygen concentrated near 100 kpc. Circumgalactic gas within this radius cools in less than 1 Gyr and radiates ˜ {10}42.2 erg s-1 overall. The feedback power necessary to maintain such oxygen-rich atmospheres for many Gyr cannot be easily supplied by galactic supernovae. However, massive central black holes in star-forming galaxies may generate sufficient accretion power and intermittent shock waves at r˜ 100 {kpc} to balance circumgalactic radiation losses in late-type {L}\\star galaxies. The relative absence of O vi absorption observed in early-type, passive {L}\\star galaxies may arise from enhanced AGN feedback from their more massive central black holes.

  8. Multiple source heat pump

    Science.gov (United States)

    Ecker, Amir L.

    1983-01-01

    A heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating a fluid in heat exchange relationship with a refrigerant fluid, at least three refrigerant heat exchangers, one for effecting heat exchange with the fluid, a second for effecting heat exchange with a heat exchange fluid, and a third for effecting heat exchange with ambient air; a compressor for compressing the refrigerant; at least one throttling valve connected at the inlet side of a heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circuit and pump for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and directional flow of refrigerant therethrough for selecting a particular mode of operation. Also disclosed are a variety of embodiments, modes of operation, and schematics therefor.

  9. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  10. Heat pump technology

    CERN Document Server

    Von Cube, Hans Ludwig; Goodall, E G A

    2013-01-01

    Heat Pump Technology discusses the history, underlying concepts, usage, and advancements in the use of heat pumps. The book covers topics such as the applications and types of heat pumps; thermodynamic principles involved in heat pumps such as internal energy, enthalpy, and exergy; and natural heat sources and energy storage. Also discussed are topics such as the importance of the heat pump in the energy industry; heat pump designs and systems; the development of heat pumps over time; and examples of practical everyday uses of heat pumps. The text is recommended for those who would like to kno

  11. Heating and cooling with gas-fired heat-pumps; Heizen und Kuehlen mit Gas-Waermepumpen

    Energy Technology Data Exchange (ETDEWEB)

    Stadelmann, M.

    2008-07-01

    This article takes a look at the use of gas-fired absorption heat-pumps in combined cooling and heating applications. Savings in investments and reduced primary energy consumption along with the resulting lower gas costs are noted. The operation of such 'reversible' systems that use ammonia as a working fluid is briefly described. An installation at a filling station in Taverne, Switzerland, is described. A further installation at a gas utility depot in Givisiez, Switzerland, is also looked at. Here, the gas-powered heat-pump system works together with a solar installation to provide space-heating and cooling as well as hot-water preparation.

  12. Graphene oxide reduction by microwave heating

    Energy Technology Data Exchange (ETDEWEB)

    Longo, Angela; Carotenuto, Gianfranco [Institute for Polymers, Composites, and Biomaterials, National Research Council, Piazzale Enrico Fermi 1, 80055 Portici (Italy)

    2016-05-18

    The possibility to prepare thermal reduced graphene oxide (Tr-GO) colloidal suspensions by microwave heating of graphene oxide (GO) suspensions in N-methyl-2-pyrrolidone (NMP) has been investigated. According to transmission electron microscopy (TEM) and absorption and emission spectroscopy characterization, such a type of thermal reduction does not lead to graphene quantum dots formation because only mono-functional oxygen-containing groups are removed.

  13. Surface Texturing Investigated for a High Solar Absorptance Low Infrared Emittance Solar Collector

    Science.gov (United States)

    Jaworske, Donald A.

    2001-01-01

    The objective of this work was to design, build, and vacuum test a high solar absorptance, low infrared emittance solar collector for heat engine and thermal switching applications. Mini-satellites proposed by the Applied Physics Laboratory for operation in environments that are subject to radiation threat may utilize a heat engine for power and a thermal bus for thermal control. To achieve this goal, a surface having high solar absorptance and low infrared emittance is needed. At the NASA Glenn Research Center, one concept being pursued to achieve this goal is texturing high thermal conductivity graphite epoxy composites using a directed atomic oxygen beam and then coating the textured surface with a reflective metallic coating. Coupons were successfully textured, coated, and evaluated. A variety of texturing conditions were explored, and textures were documented by scanning electron microscopy. Copper, gold, silver, iridium, and aluminum coatings were applied, and the highest solar absorptance to infrared emittance ratio was found to be 1.3. A full-sized solar collector was manufactured with this ratio, and the amount of heat collected was observed using an Inconel calorimeter installed in a bench-top vacuum chamber equipped with a solar simulator. Results to date indicate good heat flow through the system, with 9 W of heat flow measured by the calorimeter.

  14. Simulation Model for Dynamic Operation of Double-Effect Absorption Chillers

    Directory of Open Access Journals (Sweden)

    Ahmed Mojahid Sid Ahmed Mohammed Salih

    2014-07-01

    Full Text Available The development in the field of refrigeration and air conditioning systems driven by absorption cycles acquired a considerable importance recently. For commercial absorption chillers, an essential challenge for creating chiller model certainly is the shortage of components technical specifications. These kinds of specifications are usually proprietary for chillers producers. In this paper, a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations is presented. The chiller studied is Lithium bromide-water with capacity of 1250 RT (Refrigeration Tons. The governing equations of the dynamic operation of the chiller are developed. From available design information, the values of the overall heat transfer coefficients multiplied by the surface area are computed. The dynamic operation of the absorption chiller is simulated to study the performance of the system. The model is able to provide essential details of the temperature, concentration, and flow rate at each state point in the chiller.

  15. Computational model of heterogeneous heating in melanin

    Science.gov (United States)

    Kellicker, Jason; DiMarzio, Charles A.; Kowalski, Gregory J.

    2015-03-01

    Melanin particles often present as an aggregate of smaller melanin pigment granules and have a heterogeneous surface morphology. When irradiated with light within the absorption spectrum of melanin, these heterogeneities produce measurable concentrations of the electric field that result in temperature gradients from thermal effects that are not seen with spherical or ellipsoidal modeling of melanin. Modeling melanin without taking into consideration the heterogeneous surface morphology yields results that underestimate the strongest signals or over{estimate their spatial extent. We present a new technique to image phase changes induced by heating using a computational model of melanin that exhibits these surface heterogeneities. From this analysis, we demonstrate the heterogeneous energy absorption and resulting heating that occurs at the surface of the melanin granule that is consistent with three{photon absorption. Using the three{photon dluorescence as a beacon, we propose a method for detecting the extents of the melanin granule using photothermal microscopy to measure the phase changes resulting from the heating of the melanin.

  16. Latent heat flux measurements over complex terrain by airborne water vapour and wind lidars

    National Research Council Canada - National Science Library

    Kiemle, Christoph; Wirth, Martin; Fix, Andreas; Rahm, Stephan; Corsmeier, Ulrich; Di Girolamo, Paolo

    2011-01-01

    Vertical profiles of the latent heat flux in a convective boundary layer (CBL) are obtained for the first time over complex terrain with airborne water vapour differential absorption lidar and Doppler wind lidar...

  17. Measurement of Acoustic Attenuation and Absorption Coefficients using Thermometry

    Science.gov (United States)

    Morris, Hugh; Rivens, Ian; Shaw, Adam; ter Haar, Gail

    2007-05-01

    Accurate knowledge of both the attenuation and the absorption coefficient of tissue are required when planning an optimal high intensity focused ultrasound treatment. A novel technique for simple measurement of this parameters has been developed in which a thin-film thermocouple (TFT) is placed between two layers of tissue of different thicknesses. The sample can be rotated about an axis through the junction of the TFT so that it can be insonated from either side leaving the tissue adjacent to the junction unchanged, but changing the overlying thickness. The attenuation and absorption coefficients can be calculated from the heating curves measured in the two orientations. Experiments have been carried out in both tissue mimicking material (TMM) and in ex vivo liver tissue. Weakly focused transducers, resonant at 1.05 MHz, 2.4 MHz and 3.55 MHz were used at free-field spatial peak intensities of 9-14 W/cm2. The temperature rise was measured as a function of time using a TFT. These thermocouples are not subject to the viscous heating artefact that is common to other thermocouple devices and so are advantageous for this purpose. Alignment was achieved with a 3D automated gantry system, which was controlled with specialised software. Timing and data acquisition were also controlled with this software. All experiments were carried out in degassed water. Results for TMM and degassed excised bovine liver are presented.

  18. Photocell heat engine solar power systems

    Science.gov (United States)

    Taussig, R. T.; Vaidyanathan, T. S.; Hoverson, S.; Bruzzone, C.; Christiansen, W.

    1980-01-01

    A combined photocell heat engine concept is proposed for high efficiency solar energy conversion in space. In this concept the short wavelength portion of the solar spectrum is split by a dichroic filter and sent to a bank of photocells. The long wave-length remainder of the spectrum is used by the heat engine. This technique allows the photocells to operate with the minimum amount of waste heat, increasing their efficiency and reducing the amount of cooling required. The heat engine operates by direct absorption in a working fluid containing broadband absorber molecules or particulates. A window in the heat engine admits the long wave-lengths from the solar spectrum. The window may also reflect a portion of the internal gaseous reradiation spectrum (e.g., a heat mirror) to help reduce radiation losses. Flow-induced thermal gradients may also reduce reradiation losses in the case of optically thick working fluids. The efficiencies computed for the photocell heat engine solar energy converter can be as high as 42 percent.

  19. Oscillating heat pipes

    CERN Document Server

    Ma, Hongbin

    2015-01-01

    This book presents the fundamental fluid flow and heat transfer principles occurring in oscillating heat pipes and also provides updated developments and recent innovations in research and applications of heat pipes. Starting with fundamental presentation of heat pipes, the focus is on oscillating motions and its heat transfer enhancement in a two-phase heat transfer system. The book covers thermodynamic analysis, interfacial phenomenon, thin film evaporation,  theoretical models of oscillating motion and heat transfer of single phase and two-phase flows, primary  factors affecting oscillating motions and heat transfer,  neutron imaging study of oscillating motions in an oscillating heat pipes, and nanofluid’s effect on the heat transfer performance in oscillating heat pipes.  The importance of thermally-excited oscillating motion combined with phase change heat transfer to a wide variety of applications is emphasized. This book is an essential resource and learning tool for senior undergraduate, gradua...

  20. Heat Related Illnesses

    National Research Council Canada - National Science Library

    Carter, R; Cheuvront, S. N; Sawka, M. N

    2006-01-01

    .... The risk of serious heat illness can be markedly reduced by implementing a variety of countermeasures, including becoming acclimated to the heat, managing heat stress exposure, and maintaining hydration...

  1. Heat Roadmap Europe 1

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Østergaard, Poul Alberg

    2012-01-01

    Heat Roadmap Europe (Pre-study 1) investigates the role of district heating in the EU27 energy system by mapping local conditions across Europe, identifying the potential for district heating expansion, and subsequently simulating the potential resource in an hourly model of the EU27 energy system....... In 2010, approximately 12% of the space heating demand in Europe is met by district heating, but in this study four alternative scenarios are considered for the EU27 energy system: 1. 2010 with 30% district heating 2. 2010 with 50% district heating 3. 2030 with 30% district heating 4. 2050 with 50......% district heating These scenarios are investigated in two steps. Firstly, district heating replaces individual boilers by converting condensing power plants to combined heat and power plants (CHP) to illustrate how district heating improves the overall efficiency of the energy system. In the second step...

  2. Multidimensional Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of multidimensional heat conduction. General heat conduction equation in three dimensions. Steay state, analytical solutions. The Laplace equation. Method of separation of variables. Principle of superposition. Shape factors. Transient, multidimensional heat conduction....

  3. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... sweating; nausea; and giddiness. Symptoms of heat stroke (late stage of heat illness) include flushed, hot, dry ... consciousness, vomiting or a high body temperature. For late stage heat stroke symptoms, cool the person further ...

  4. Energy-efficient cooling using absorption chilling; Energieeffizient kuehlen mittels Absorber

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, W.

    2009-07-01

    This article takes a look at a new hotel in Basel, Switzerland, whose 112 rooms are cooled in summer using a heat-driven absorption refrigeration system. The heat is provided by the city's district heating system. The IWB utility supports the environmental management efforts of the hotel chain by supplying heat during the summer at reduced rates. Figures on the system are quoted. The double facade of this 2-star hotel and its ceiling-integrated heating and cooling system are looked at and the roof-mounted cold generation system is described. The roof-mounted elements of the cooling system and the stipulations of the City of Basel regarding appearance and noise abatement are commented on.

  5. Dual purpose absorption machines in an energy system based on waste incineration; Absorptionsmaskiner foer kyl- och vaermeproduktion i energisystem med avfallsfoerbraenning

    Energy Technology Data Exchange (ETDEWEB)

    Brorsson, Maria [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

    2005-03-01

    The demand for district cooling in Sweden has been increasing during the recent years and is expected to increase even more. The reason for this is for example more frequent use of computers and higher demand for indoor climate control via air conditioning. During the summer there is also a surplus of heat, especially in energy systems that includes waste incineration. This surplus makes it interesting to consider heat-driven cooling as an alternative to satisfy the increasing demand of district cooling. Today many energy systems in Sweden use absorption heat pumps, for production of district heating using waste heat from the combustion units. To this point the absorption heat pumps have not been considered as chillers due to their relatively high investment cost in combination with the short cooling season. However, the surplus of heat during the summer season means that there is access to 'free' driving heat for the absorption chillers. This would be a cheap and environmentally friendly way to produce district cooling. The aim of this study was to examine the opportunities for using absorption machines for production of district heating during wintertime and district cooling during summertime. Factors to be considered were how this change would be made technically and during which months the absorption heat pumps should be used for cold and heat production, respectively. In addition a comparison between absorption cooling and other cooling techniques was made. The study was based on Vattenfall Vaerme Uppsala ABs (VVU) energy system in Uppsala. VVU has recently invested in two new absorption heat pumps that, together with four old ones, are planned to produce district heating as well as district cooling depending on the season. The results of the study are: The technical change between heat and cold production with absorption heat pumps is relatively simple. When used as a chiller the evaporator heat is taken from the district cooling return water, which

  6. Sound absorption with green materials

    Science.gov (United States)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-07-01

    Green materials are a valid alternative to traditional materials that are by-products of processing oil. At the end of their useful life, green materials can be disposed of without polluting the environment. They are now being used in the construction and automotive industries. While, studies are currently being carried out in the aviation sector on the use of green materials for non-structural components of airplanes. Green materials can be used to improve the acoustic comfort inside buildings as well as mitigate reverberation, echoes effects and reduce the transmission of noise between rooms. In this paper, the acoustic measurements of the properties of green materials are reported. The absorption coefficient of samples of the materials were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube, with the flow resistance being measured.

  7. HI Absorption in Merger Remnants

    Science.gov (United States)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  8. Regenerative adsorbent heat pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    1991-01-01

    A regenerative adsorbent heat pump process and system is provided which can regenerate a high percentage of the sensible heat of the system and at least a portion of the heat of adsorption. A series of at least four compressors containing an adsorbent is provided. A large amount of heat is transferred from compressor to compressor so that heat is regenerated. The process and system are useful for air conditioning rooms, providing room heat in the winter or for hot water heating throughout the year, and, in general, for pumping heat from a lower temperature to a higher temperature.

  9. Absorption boundary conditions for geomertical acoustics

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2012-01-01

    Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, the absorption coefficients or surface impedances of the boundary surfaces can be used, but no guideline has been developed...... solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. It is concluded that the impedance and random incidence absorption boundary conditions produce reasonable results with some exceptions at low frequencies for acoustically soft materials....

  10. Vitamin B12 absorption from eggs.

    Science.gov (United States)

    Doscherholmen, A; McMahon, J; Ripley, D

    1975-09-01

    The assimilation of 57Co B12 from in vivo labeled eggs was much inferior to that of a comparable amount of crystalline 57Co B12. Furthermore, the absorption varied with the form in which the eggs were served. Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.

  11. Heat pumps in district heating networks

    DEFF Research Database (Denmark)

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

    constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... are calculated using an energy system model which includes power plants, heat pumps and district heating consumption profiles. The model is developed with focus on accurate representation of the performance of the units in different locations and operating modes. The model can assist in investment decisions...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

  12. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We developed a highly sensitive and compact instrument to directly measure particulate matter (PM) optical absorption. This device is based on differential...

  13. Absorption bands in the spectrum of Io

    Science.gov (United States)

    Cruikshank, D. P.; Jones, T. J.; Pilcher, C. B.

    1978-01-01

    Near-infrared spectra of Io in the region from 2.8 to 4.2 microns are reported which show distinct absorption features, the most notable at 4.1 microns. Frozen volatiles or atmospheric gases cannot account for these absorptions, nor do they resemble those seen in common silicate rocks. Several candidate substances, most notably nitrate and carbonate salts, show absorption features in this spectral region; the deepest band in the spectrum may be a nitrate absorption. The satellite surface is shown to be anhydrous, as indicated by the absence of the 3-micron bound water band.

  14. The effect of sample holder geometry on electromagnetic heating of nanoparticle and NaCl solutions at 13.56 MHz.

    Science.gov (United States)

    Li, Dongxiao; Jung, Yun Suk; Kim, Hong Koo; Chen, Junda; Geller, David A; Shuba, Mikhail V; Maksimenko, Sergey A; Patch, Sarah; Forati, Ebrahim; Hanson, George W

    2012-12-01

    Electromagnetic absorption and subsequent heating of nanoparticle solutions and simple NaCl ionic solutions is examined for biomedical applications in the radiofrequency range at 13.56 MHz. It is shown via both theory and experiment that for in vitro measurements the shape of the solution container plays a major role in absorption and heating.

  15. Vasculature of the hive: heat dissipation in the honey bee (Apis mellifera) hive.

    Science.gov (United States)

    Bonoan, Rachael E; Goldman, Rhyan R; Wong, Peter Y; Starks, Philip T

    2014-06-01

    Eusocial insects are distinguished by their elaborate cooperative behavior and are sometimes defined as superorganisms. As a nest-bound superorganism, individuals work together to maintain favorable nest conditions. Residing in temperate environments, honey bees (Apis mellifera) work especially hard to maintain brood comb temperature between 32 and 36 °C. Heat shielding is a social homeostatic mechanism employed to combat local heat stress. Workers press the ventral side of their bodies against heated surfaces, absorb heat, and thus protect developing brood. While the absorption of heat has been characterized, the dissipation of absorbed heat has not. Our study characterized both how effectively worker bees absorb heat during heat shielding, and where worker bees dissipate absorbed heat. Hives were experimentally heated for 15 min during which internal temperatures and heat shielder counts were taken. Once the heat source was removed, hives were photographed with a thermal imaging camera for 15 min. Thermal images allowed for spatial tracking of heat flow as cooling occurred. Data indicate that honey bee workers collectively minimize heat gain during heating and accelerate heat loss during cooling. Thermal images show that heated areas temporarily increase in size in all directions and then rapidly decrease to safe levels (<37 °C). As such, heat shielding is reminiscent of bioheat removal via the cardiovascular system of mammals.

  16. Vasculature of the hive: heat dissipation in the honey bee ( Apis mellifera) hive

    Science.gov (United States)

    Bonoan, Rachael E.; Goldman, Rhyan R.; Wong, Peter Y.; Starks, Philip T.

    2014-06-01

    Eusocial insects are distinguished by their elaborate cooperative behavior and are sometimes defined as superorganisms. As a nest-bound superorganism, individuals work together to maintain favorable nest conditions. Residing in temperate environments, honey bees ( Apis mellifera) work especially hard to maintain brood comb temperature between 32 and 36 °C. Heat shielding is a social homeostatic mechanism employed to combat local heat stress. Workers press the ventral side of their bodies against heated surfaces, absorb heat, and thus protect developing brood. While the absorption of heat has been characterized, the dissipation of absorbed heat has not. Our study characterized both how effectively worker bees absorb heat during heat shielding, and where worker bees dissipate absorbed heat. Hives were experimentally heated for 15 min during which internal temperatures and heat shielder counts were taken. Once the heat source was removed, hives were photographed with a thermal imaging camera for 15 min. Thermal images allowed for spatial tracking of heat flow as cooling occurred. Data indicate that honey bee workers collectively minimize heat gain during heating and accelerate heat loss during cooling. Thermal images show that heated areas temporarily increase in size in all directions and then rapidly decrease to safe levels (<37 °C). As such, heat shielding is reminiscent of bioheat removal via the cardiovascular system of mammals.

  17. Technical and economic aspects of waste heat utilization

    Directory of Open Access Journals (Sweden)

    Smolen Slavomir

    2007-01-01

    Full Text Available The main aim of the following presentation is the comparison and evaluation of the conditions for waste heat utilization in Germany and in Poland. This paper presents synthetically the results of economic analysis of the different technical variants. The employment of heat pumps and other heat transformers, respectively, can reduce the energy consumption, but using of those technical possibilities depends mainly on the economic aspects. The main parameters of the financial calculations were the energy and equipment costs but beyond it a number of other factors were also considered and compared, for example calculation interests, profit tax level and similar. Four different technical alternatives were analyzed, it is using of absorption heat pump, compression heat pump, heat transformer (absorption, and a special combined system with gas motor to drive of heat pump compressor. The capital value as main result of the investigations is in Poland generally lower because of relatively high investment cost and lower energy prices compared to the situation in Germany and West Europe. The basis for the presented comparative analysis was an industrial project in Germany which effected in development of concepts for waste heat using. .

  18. Nature's Heat Exchangers.

    Science.gov (United States)

    Barnes, George

    1991-01-01

    Discusses the heat-transfer systems of different animals. Systems include heat conduction into the ground, heat transferred by convection, heat exchange in lizards, fish and polar animals, the carotid rete system, electromagnetic radiation from animals and people, and plant and animal fiber optics. (MDH)

  19. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  20. Solar Heating Equipment

    Science.gov (United States)

    1981-01-01

    Solar Unlimited, Inc.'s suncatcher line includes a variety of solar arrays, derived from NASA's satellite program: water heating only, partial home heating, or water and whole house central heating. Solar Unlimited developed a set of vigorous requirements to avoid problems common to solar heating technologies.

  1. Rotary magnetic heat pump

    Science.gov (United States)

    Kirol, Lance D.

    1988-01-01

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

  2. Time-resolved detection of temperature, concentration, and pressure in a shock tube by intracavity absorption spectroscopy

    Science.gov (United States)

    Fjodorow, Peter; Fikri, Mustapha; Schulz, Christof; Hellmig, Ortwin; Baev, Valery M.

    2016-06-01

    In this paper, we demonstrate the first application of intracavity absorption spectroscopy (ICAS) for monitoring species concentration, total pressure, and temperature in shock-tube experiments. ICAS with a broadband Er3+-doped fiber laser is applied to time-resolved measurements of absorption spectra of shock-heated C2H2. The measurements are performed in a spectral range between 6512 and 6542 cm-1, including many absorption lines of C2H2, with a time resolution of 100 µs and an effective absorption path length of 15 m. Up to 18-times increase of the total pressure and a temperature rise of up to 1200 K have been monitored. Due to the ability of simultaneously recording many absorption lines in a broad spectral range, the presented technique can also be applied to multi-component analysis of transient single-shot processes in reactive gas mixtures in shock tubes, pulse detonation engines, or explosions.

  3. Preliminary evaluation of a pre-industrial air-cooled LiBr-H2O small capacity absorption machine

    OpenAIRE

    Farnós Baulenas, Joan; Castro González, Jesús; Morales Ruíz, Sergio; García Rivera, Eduardo; Oliva Llena, Asensio

    2014-01-01

    The paper describes the thermal design, and evaluates the preliminary operational results of a small capacity pre-industrial LiBr-H2O air-cooled absorption machine in order to validate a numerical model and apply it to simulate a new 7kW LiBr-H2O air-cooled absorption chiller, conceived for low temperature driven, solar cooling or wasted heat. This numerical model is able to simulate the dynamical thermohydraulic behavior of a single-effect absorption machine in transient conditions, being im...

  4. Hierarchical Decomposition Thermodynamic Approach for the Study of Solar Absorption Refrigerator Performance

    Directory of Open Access Journals (Sweden)

    Emma Berrich Betouche

    2016-03-01

    Full Text Available A thermodynamic approach based on the hierarchical decomposition which is usually used in mechanical structure engineering is proposed. The methodology is applied to an absorption refrigeration cycle. Thus, a thermodynamic analysis of the performances on solar absorption refrigerators is presented. Under the hypothesis of an endoreversible model, the effects of the generator, the solar concentrator and the solar converter temperatures, on the coefficient of performance (COP, are presented and discussed. In fact, the coefficient of performance variations, according to the ratio of the heat transfer areas of the high temperature part (the thermal engine 2 Ah and the heat transfer areas of the low temperature part (the thermal receptor Ar variations, are studied in this paper. For low values of the heat-transfer areas of the high temperature part and relatively important values of heat-transfer areas of the low temperature part as for example Ah equal to 30% of Ar, the coefficient of performance is relatively important (approximately equal to 65%. For an equal-area distribution corresponding to an area ratio Ah/Ar of 50%, the COP is approximately equal to 35%. The originality of this deduction is that it allows a conceptual study of the solar absorption cycle.

  5. Cryogenic Thermal Absorptance Measurements on Small-Diameter Stainless Steel Tubing

    Science.gov (United States)

    Tuttle, James; Jahromi, Amir; Canavan, Edgar; DiPirro, Michael

    2015-01-01

    The Mid Infrared Instrument (MIRI) on the James Webb Space Telescope includes a mechanical cryocooler which cools its detectors to their 6 Kelvin operating temperature. The coolant gas flows through several meters of small-diameter stainless steel tubing, which is exposed to thermal radiation from its environment. Over much of its length this tubing is gold-plated to minimize the absorption of this radiant heat. In order to confirm that the cryocooler will meet MIRI's requirements, the thermal absorptance of this tubing was measured as a function of its environment temperature. We describe the measurement technique and present the results.

  6. LASER PLASMA AND LASER APPLICATIONS: Plasma transparency in laser absorption waves in metal capillaries

    Science.gov (United States)

    Anisimov, V. N.; Kozolupenko, A. P.; Sebrant, A. Yu

    1988-12-01

    An experimental investigation was made of the plasma transparency to heating radiation in capillaries when absorption waves propagated in these capillaries as a result of interaction with a CO2 laser pulse of 5-μs duration. When the length of the capillary was in excess of 20 mm, total absorption of the radiation by the plasma was observed at air pressures of 1-100 kPa. When the capillary length was 12 mm, a partial recovery of the transparency took place. A comparison was made with the dynamics and recovery of the plasma transparency when breakdown of air took place near the free surface.

  7. Quantum dynamics of an optical cavity coupled to a thin semitransparent membrane: Effect of membrane absorption

    Energy Technology Data Exchange (ETDEWEB)

    Biancofiore, C.; Karuza, M.; Galassi, M.; Natali, R.; Vitali, D. [School of Science and Technology, Physics Division, University of Camerino, via Madonna delle Carceri, 9, I-62032 Camerino (Italy) and INFN, Sezione di Perugia (Italy); Tombesi, P.; Di Giuseppe, G. [School of Science and Technology, Physics Division, University of Camerino, via Madonna delle Carceri, 9, I-62032 Camerino (Italy) and INFN, Sezione di Perugia (Italy); CriptoCam S.r.l., via Madonna delle Carceri 9, I-62032 Camerino (Italy)

    2011-09-15

    We study the quantum dynamics of the cavity optomechanical system formed by a Fabry-Perot cavity with a thin vibrating membrane at its center. We determine in particular to what extent optical absorption by the membrane hinders reaching a quantum regime for the cavity-membrane system. We show that even though membrane absorption may significantly lower the cavity finesse and also heat the membrane, one can still simultaneously achieve ground state cooling of a vibrational mode of the membrane and stationary optomechanical entanglement with state-of-the-art apparatuses.

  8. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    Hansen, Kenneth; Connolly, David; Lund, Henrik

    2015-01-01

    of supplying sustainable heating. Different heat production options are included in terms of individual and community heating systems. Furthermore, the levelised cost of supplying sustainable heat is estimated for both a single technology and from an energy system perspective. The results are analysed...... by assessing various parameters such as socio-economic costs and energy efficiency improvements in the national energy systems. The results demonstrate the economically feasible levels of heat savings and heat production for various European countries, highlighting differences in their national conditions......The cost of heat savings in buildings increase as more heat savings are achieved due to the state of the building stock and hence, alternatives other than savings typically become more economically feasible at a certain level of heat reductions. It is important to identify when the cost of heat...

  9. 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...... 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....... 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...

  10. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    Connolly, David; Mathiesen, Brian Vad; Lund, Henrik

    2015-01-01

    information systems (GIS) and energy system analyses. In this report, the inputs for other modelling tools such as PRIMES are presented, in order to enable other researches to generate similar heating scenarios for Europe. Although Heat Roadmap Europe presents a complete heat strategy for Europe, which...... includes energy efficiency, individual heating units (such as boilers and heat pumps), and heat networks, the recommendations here are primarily relating to the potential and modelling of district heating. Although other solutions will play a significant role in decarbonising the heating and cooling sector...... in a low-carbon energy system context, so we have focused on this area based on our extensive experience in this area [1-10]. This report includes guidelines on the potential heat demand in European buildings that can be met by district heating as well as some general guidelines on how this district...

  11. EM-wave absorption properties of hollow spiral iron particles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenqiang, E-mail: zwqcau@gmail.com [College of Engineering, China Agricultural University, Beijing 100083 (China); Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China); Zhang, Deyuan [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, Beihang University, Beijing 100191 (China)

    2015-12-15

    Hollow iron spiral particles were fabricated successfully by thermal decomposition method, and they were heat-treated at different temperatures in N{sub 2} atmosphere. The electromagnetic wave absorption properties of hollow iron spiral particles were investigated ranging between 1 GHz and 18 GHz. The results indicated that the phase structures of the particles changed from amorphous to nanocrystal with the treating temperature rising, also causing the significant change in electromagnetic parameters and the reflection loss. The reflection loss could reach −33 dB at 16.2 GHz, indicating that the hollow iron spiral particles had the potential to be used in prepare the a high property EM-wave absorber. - Highlights: • Hollow iron spiral particles were fabricated by thermal decomposition method. • The particles changed from amorphous to nanocrystals with heat-treatment. • Particles’ EM-parameters have a great change after high temperature heat-treatment. • RL results show the particles have potential to be high property EM-wave absorber.

  12. Absorption of ozone by porous particles

    Energy Technology Data Exchange (ETDEWEB)

    Afanas' ev, V.P.; Dorofeev, S.B.; Sinitsyn, V.I.; Smirnov, B.M.

    1981-11-01

    The absorption of ozone by porous zeolite, silica gel, and activated carbon particles has been studied experimentally. It was shown that in addition to absorption, dissociation of ozone on the surface plays an important and sometimes decisive role. The results obtained were used to analyze the nature of ball lightning.

  13. Scalar absorption by charged rotating black holes

    Science.gov (United States)

    Leite, Luiz C. S.; Benone, Carolina L.; Crispino, Luís C. B.

    2017-08-01

    We compute numerically the absorption cross section of planar massless scalar waves impinging upon a Kerr-Newman black hole with different incidence angles. We investigate the influence of the black hole electric charge and angular momentum in the absorption spectrum, comparing our numerical computations with analytical results for the limits of high and low frequency.

  14. Iron absorption from intrinsically-labeled lentils

    Science.gov (United States)

    Low iron (Fe) absorption from important staple foods may contribute to Fe deficiency in developing countries. To date, there are few studies examining the Fe bioavailability of pulse crops as commonly prepared and consumed by humans. The objectives of this study were to characterize the Fe absorpt...

  15. Absorption, bioavailability and metabolism of flavonoids

    NARCIS (Netherlands)

    Hollman, P.C.H.

    2004-01-01

    To unravel mechanisms of action of dietary flavonoids in their potential role in disease prevention, it is crucial to know the factors that determine their release from foods, their extent of absorption, and their fate in the organism. Research on absorption, metabolism, and bioavailability of

  16. Emission and Absorption Entropy Generation in Semiconductors

    DEFF Research Database (Denmark)

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika

    2013-01-01

    materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconductor solar cell even further than the Landsberg limit. The results are derived from purely thermodynamical...

  17. Low absorptance porcelain-on-aluminum coating

    Science.gov (United States)

    Leggett, H.

    1979-01-01

    Porcelain thermal-control coating for aluminum sheet and foil has solar absorptance of 0.22. Specially formulated coating absorptance is highly stable, changing only 0.03 after 1,000 hours of exposure to simulated sunlight and can be applied by standard commercial methods.

  18. A Low-Cost Quantitative Absorption Spectrophotometer

    Science.gov (United States)

    Albert, Daniel R.; Todt, Michael A.; Davis, H. Floyd

    2012-01-01

    In an effort to make absorption spectrophotometry available to high school chemistry and physics classes, we have designed an inexpensive visible light absorption spectrophotometer. The spectrophotometer was constructed using LEGO blocks, a light emitting diode, optical elements (including a lens), a slide-mounted diffraction grating, and a…

  19. Regularity of the interband light absorption coefficient

    Indian Academy of Sciences (India)

    Light absorption coefficient; density of states; random operators. 1. ... The operators H. ± ω may be unbounded. However, the finite volume operators H ,ω are symmetric finite-dimensional matrices when is a finite set, so their ...... [1] Atoyan M S, Kazaryan E M and Sarkisyan H A, Interband light absorption in parabolic.

  20. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Membrane gas absorption is a new, efficient and flexible way to carry out gas-liquid contacting operations with hollow fibre membranes. Advantages of gas absorption membranes over conventional G-L contactors are: -High specific surface area and rapid mass transfer resulting in very compact and low

  1. Terahertz absorption spectrum of triacetone triperoxide (TATP)

    Science.gov (United States)

    Wilkinson, John; Konek, Christopher T.; Moran, Jesse S.; Witko, Ewelina M.; Korter, Timothy M.

    2009-08-01

    We report here, for the first time, the terahertz absorption spectrum of triacetone triperoxide (TATP). The experimental spectra are coupled with solid-state density functional theory, and preliminary assignments are provided to gain physical insight into the experimental spectrum. The calculated absorption coefficients are in excellent agreement with experiment.

  2. Introduction to heat transfer

    CERN Document Server

    SUNDÉN, B

    2012-01-01

    Presenting the basic mechanisms for transfer of heat, Introduction to Heat Transfer gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers.

  3. Integration of a molten carbonate fuel cell with a direct exhaust absorption chiller

    Science.gov (United States)

    Margalef, Pere; Samuelsen, Scott

    A high market value exists for an integrated high-temperature fuel cell-absorption chiller product throughout the world. While high-temperature, molten carbonate fuel cells are being commercially deployed with combined heat and power (CHP) and absorption chillers are being commercially deployed with heat engines, the energy efficiency and environmental attributes of an integrated high-temperature fuel cell-absorption chiller product are singularly attractive for the emerging distributed generation (DG) combined cooling, heating, and power (CCHP) market. This study addresses the potential of cooling production by recovering and porting the thermal energy from the exhaust gas of a high-temperature fuel cell (HTFC) to a thermally activated absorption chiller. To assess the practical opportunity of serving an early DG-CCHP market, a commercially available direct fired double-effect absorption chiller is selected that closely matches the exhaust flow and temperature of a commercially available HTFC. Both components are individually modeled, and the models are then coupled to evaluate the potential of a DG-CCHP system. Simulation results show that a commercial molten carbonate fuel cell generating 300 kW of electricity can be effectively coupled with a commercial 40 refrigeration ton (RT) absorption chiller. While the match between the two "off the shelf" units is close and the simulation results are encouraging, the match is not ideal. In particular, the fuel cell exhaust gas temperature is higher than the inlet temperature specified for the chiller and the exhaust flow rate is not sufficient to achieve the potential heat recovery within the chiller heat exchanger. To address these challenges, the study evaluates two strategies: (1) blending the fuel cell exhaust gas with ambient air, and (2) mixing the fuel cell exhaust gases with a fraction of the chiller exhaust gas. Both cases are shown to be viable and result in a temperature drop and flow rate increase of the

  4. Enriching Absorptive Capacity Through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper Jaap; Becker-Ritterspach, Florian; Saka-Helmhout, Ayse

    absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context. Second, the findings illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling or constraining local interaction patterns......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within MNEs. But how individual behaviour translates to absorptive capacity at the subsidiary level, and exactly how this is contingent on subsidiaries’ social context, remains under-addressed. This not only...... limits our understanding of the causal linkage between individual and organizational level absorptive capacity, it also hampers further research on potentially relevant managerial and organizational antecedents, and limits the implications we can draw for practitioners in the field seeking to increase...

  5. Enriching Absorptive Capacity through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper J.; Saka-Helmhout, Ayse; Becker-Ritterspach, Florian

    2012-01-01

    for subsidiary absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context and the development of local applications. The findings also illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within multinational enterprises. But how individual behaviour translates into absorptive capacity at the subsidiary level, and how this is contingent on subsidiaries' social context, remains under......-addressed. This not only limits our understanding of the relationship between individual- and organizational-level absorptive capacity, but also hampers further research on potentially relevant managerial and organizational antecedents, and limits the implications we can draw for practitioners who seek to increase...

  6. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  7. [Protein absorption in children with giardiasis].

    Science.gov (United States)

    Vega-Franco, L; Alvarez, E L; Romo, G; Bernal, R M

    1982-01-01

    With the object of investigating if Giardiasis interferes in the intestinal absorption of proteins, a study was made testing the absorption of gelatin in eleven. The determination of alpha-aminonitrogen, before giving gelatin, and the increase shown two hours later, was the criterion used to measure the capacity of absorption. Once the estimated basal had been carried out each of the children received tinidazol for three days, after which the large amount of gelatin was given once again so as to estimate any changes in the absorption, one the parasite had been eliminated. The results demonstrate that the presence of giardia in the intestine significantly restricts the absorption of the gelatin. We offer as proof the results of these findings in the growth of children who harbour this parasite.

  8. Analysis of selected surface characteristics and latent heat storage for passive solar space heating

    Energy Technology Data Exchange (ETDEWEB)

    Fthenakis, V.; Leigh, R.

    1981-12-01

    Results are presented of an analysis of the value of various technical improvements in the solar collector and thermal storage subsystems of passive solar residential, agricultural, and industrial systems for two regions of the country. The evaluated improvements are: decreased emissivity and increased absorptivity of absorbing surfaces, decreased reflectivity, and decreased emissivity of glazing surface, and the substitution of sensible heat storage media with phase change materials. The value of each improvement is estimated by the additional energy savings resulting from the improvement.

  9. Neoclassical offset toroidal velocity and auxiliary ion heating in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Lazzaro, E., E-mail: lazzaro@ifp.cnr.it [Istituto di Fisica del Plasma CNR (Italy)

    2016-05-15

    In conditions of ideal axisymmetry, for a magnetized plasma in a generic bounded domain, necessarily toroidal, the uniform absorption of external energy (e.g., RF or any isotropic auxiliary heating) cannot give rise to net forces or torques. Experimental evidence on contemporary tokamaks shows that the near central absorption of RF heating power (ICH and ECH) and current drive in presence of MHD activity drives a bulk plasma rotation in the co-I{sub p} direction, opposite to the initial one. Also the appearance of classical or neoclassical tearing modes provides a nonlinear magnetic braking that tends to clamp the rotation profile at the q-rational surfaces. The physical origin of the torque associated with P{sub RF} absorption could be due the effects of asymmetry in the equilibrium configuration or in power deposition, but here we point out also an effect of the response of the so-called neoclassical offset velocity to the power dependent heat flow increment. The neoclassical toroidal viscosity due to internal magnetic kink or tearing modes tends to relax the plasma rotation to this asymptotic speed, which in absence of auxiliary heating is of the order of the ion diamagnetic velocity. It can be shown by kinetic and fluid calculations, that the absorption of auxiliary power by ions modifies this offset proportionally to the injected power thereby forcing the plasma rotation in a direction opposite to the initial, to large values. The problem is discussed in the frame of the theoretical models of neoclassical toroidal viscosity.

  10. Heat stroke and related heat stress disorders.

    Science.gov (United States)

    Knochel, J P

    1989-05-01

    Medical disorders related to environmental heat exposure are exceptionally common in persons who perform hard work in hot climates. They are also common in competitive athletes as well as in persons who participate in casual exercise to maintain health. The important issue of salt and water disturbances consequent to heavy sweating in hot climates is discussed in detail as are mechanisms of potassium deficiency and its implications. The major forms of environmental heat illness including heat syncope, heat cramp, heat exhaustion, and heat stroke are presented in detail with relevant clinical examples. A discussion of the differential diagnosis of hyperthermia and rhabdomyolysis follows. Because of the difference in treatment and complications, heat stroke is subdivided into the classic variety that affects the elderly and very young and that form that follows heavy physical work and is always associated with rhabdomyolysis. Because severe heat exhaustion and heat stroke are life-threatening disorders, the chapter includes a detailed discussion of complications and plans for treatment.

  11. Monitoring Telluric Absorption with CAMAL

    Science.gov (United States)

    Baker, Ashley D.; Blake, Cullen H.; Sliski, David H.

    2017-08-01

    Ground-based astronomical observations may be limited by telluric water vapor absorption, which is highly variable in time and significantly complicates both spectroscopy and photometry in the near-infrared (NIR). To achieve the sensitivity required to detect Earth-sized exoplanets in the NIR, simultaneous monitoring of precipitable water vapor (PWV) becomes necessary to mitigate the impact of variable telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive six-inch aperture telescope dedicated to measuring PWV at the Fred Lawrence Whipple Observatory on Mount Hopkins. CAMAL utilizes three narrowband NIR filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. Here, we present the current design of CAMAL, discuss our data analysis methods, and show results from 11 nights of PWV measurements taken with CAMAL. For seven nights of data we have independent PWV measurements extracted from high-resolution stellar spectra taken with the Tillinghast Reflector Echelle Spectrometer (TRES) also located on Mount Hopkins. We use the TRES spectra to calibrate the CAMAL absolute PWV scale. Comparisons between CAMAL and TRES PWV estimates show excellent agreement, matching to within 1 mm over a 10 mm range in PWV. Analysis of CAMAL’s photometric precision propagates to PWV measurements precise to better than 0.5 mm in dry (PWV < 4 mm) conditions. We also find that CAMAL-derived PWVs are highly correlated with those from a GPS-based water vapor monitor located approximately 90 km away at Kitt Peak National Observatory, with a root mean square PWV difference of 0.8 mm.

  12. Research on the sound absorption characteristics of porous metal materials at high sound pressure levels

    Directory of Open Access Journals (Sweden)

    Xiaopeng Wang

    2015-05-01

    Full Text Available Porous metal materials are widely used in noise control with high sound pressure applications such as aircraft engine liners and combustion chambers for rocket engines due to their excellent performance of sound absorption characteristics and distinguished advantages in heat resistance, lightness, and stiffness. Understanding the effect of sound pressure on the acoustic properties of these materials is crucial when attempting to predict silencer performance. In this article, we experimentally investigate the sound absorption characteristics of porous metal materials at high sound pressure level. The effects of material parameters on the sound absorption characteristics of porous metal materials under high sound pressure level are further explored experimentally. Measurements are carried out by using a standard impedance tube that has been modified to accommodate sound pressure level of up to 150 dB. The experimental results show that with the increase in sound pressure level, the effect of sound pressure level on the sound absorption characteristics yields different variation regularities in different frequencies. The sound absorption performance of porous metal materials increases with the increase in sound pressure level in low frequency, which is reasonably consistent with the theoretical results. Under high sound pressure level, the sound absorption characteristics are significantly dependent upon the material parameters such as the metal fiber diameter, the material porosity, and the material thickness. It could provide a reliable experimental validation for the applications of porous metal materials in the area of vibration and noise control at high sound pressure levels.

  13. SiC absorption of near-infrared laser radiation at high temperatures

    Science.gov (United States)

    Adelmann, B.; Hellmann, R.

    2016-07-01

    We report on a theoretical and experimental investigation of the temperature-dependent optical absorption of nitrogen-doped 4H-SiC for a temperature range between room temperature and the decomposition point. The theoretical model is based on free carrier absorption including the temperature dependence of the electron mobility. With respect to laser material processing of silicon carbide, the analysis focusses on a near-infrared wavelength range. At room temperature, the calculated absorption is in excellent agreement to transmission and reflection measurements. For the experimental study of the absorption at higher temperatures induced by intense 1070-nm laser irradiation, a two-color pyrometer is employed with the thermal emission of the laser interaction zone being collected coaxial to the impinging laser. Exemplarily, the simulated temperature-dependent absorption is used to determine the heating of a 0.4-mm-thick 4H-SiC specimen during laser irradiation and compared to the experimentally determined temperature. In an initial time domain of the irradiation with an attained temperature below 1350 K, the simulated and measured temperatures are in good agreement. Above 1350 K, however, the measured temperature reveals a sharp and fast increase up to 2100 K which is not predicted by the model. This discrepancy is attributed to a strong additional absorption mechanism caused by carbonization at the surface which is confirmed by EDX analysis.

  14. Overview of Ionic Liquids Used as Working Fluids in Absorption Cycles

    Directory of Open Access Journals (Sweden)

    Mehrdad Khamooshi

    2013-01-01

    Full Text Available The cycle performance of refrigeration cycles depends not only on their configuration, but also on thermodynamic properties of working pairs regularly composed of refrigerant and absorbent. The commonly used working pairs in absorption cycles are aqueous solutions of either lithium bromide water or ammonia water. However, corrosion, crystallization, high working pressure, and toxicity are their major disadvantages in industrial applications. Therefore, seeking more advantageous working pairs with good thermal stability, with minimum corrosion, and without crystallization has become the research focus in the past two decades. Ionic liquids (ILs are room-temperature melting salts that can remain in the liquid state at near or below room temperature. ILs have attracted considerable attention due to their unique properties, such as negligible vapor pressure, nonflammability, thermal stability, good solubility, low melting points, and staying in the liquid state over a wide temperature range from room temperature to about 300°C. The previously mentioned highly favorable properties of ILs motivated us for carrying out the present research and reviewing the available ILs found in the literature as the working fluids of absorption cycles. Absorption cycles contain absorption heat pumps, absorption chillers, and absorption transformers.

  15. Natural refrigerants. Future heat pumps for district heating; Naturliga koeldmedier. Framtida vaermepumpar foer fjaerrvaerme

    Energy Technology Data Exchange (ETDEWEB)

    Ingvarsson, Paul; Steen Ronnermark, Ingela [Fortum Teknik och Miljoe AB, Stockholm (Sweden); Eriksson, Marcus [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Chemical Engineering and Environmental Science

    2004-01-01

    improvement in components, system and external preconditions. In the future it might be more interesting to use turbine driven heat pumps instead of electric motors. The absorption process is not considered to be an alternative to replace present heat pumps, but there is a certain niche where heat source and driving energy, considering temperature levels, are more suitable for district heating. A technique that seems to be an alternative to the compression cycle is a combination of compression and absorption. Using the media pair water and ammonia might be an interesting solution and should be compared to the alternative using carbon dioxide. A further study is recommended on this subject.

  16. Timonium Elementary School Solar Energy Heating and Cooling Augmentation Experiment. Final Engineering Report. Executive Summary.

    Science.gov (United States)

    AAI Corp., Baltimore, MD.

    This report covers a two-year and seven-month solar space heating and cooling experiment conducted at the Timonium Elementary School, Timonium, Maryland. The system was designed to provide a minimum of 50 percent of the energy required during the heating season and to determine the feasibility of using solar energy to power absorption-type…

  17. Heat Pipe Technology

    Science.gov (United States)

    1981-01-01

    The heat pipe, a sealed chamber whose walls are lined with a "wick," a thin capillary network containing a working fluid in liquid form was developed for a heat distribution system for non-rotating satellites. Use of the heat pipe provides a continuous heat transfer mechanism. "Heat tubes" that improve temperature control in plastics manufacturing equipment incorporated the heat pipe technology. James M. Stewart, an independent consultant, patented the heat tubes he developed and granted a license to Kona Corporation. The Kona Nozzle for heaterless injection molding gets heat for its operation from an external source and has no internal heating bands, reducing machine maintenance and also eliminating electrical hazards associated with heater bands. The nozzles are used by Eastman Kodak, Bic Pen Corporation, Polaroid, Tupperware, Ford Motor Company, RCA, and Western Electric in the molding of their products.

  18. EPR and optical absorption characteristics of sodic plagioclase from granite pegmatite in Kadavur, India

    Science.gov (United States)

    Anand, S. Vijay; Pandian, M. S.; Mithira, S.; Ravikumar, R. V. S. S. N.; Sambasiva Rao, P.

    The electron paramagnetic resonance (EPR) spectra of sodic plagioclase from dykes of granitic pegmatite occurring in the Kadavur area, Tamil Nadu, India, were examined at room temperature to identify paramagnetic impurities in a "low plagioclase" using EPR and optical techniques. The EPR spectra showed the presence of Fe(III) and Mn(II) impurities. After heating the plagioclase samples for various durations at 600 °C, it has been observed that the concentration of Mn(II) remained as such in one sample but completely disappeared in another sample, while there was no change in Fe(III) ion concentration after the heat treatment in either sample. Optical absorption spectra also showed Fe(II) and Fe(III) in addition to Ti(III) impurities in sodic plagioclase before heating, while after heating the relative concentration of Fe(II) and Fe(III) changed, accompanied by the disappearance of Ti(III).

  19. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Petroleo (IMP) and CENICA.

  20. The effect of volatility on percutaneous absorption.

    Science.gov (United States)

    Rouse, Nicole C; Maibach, Howard I

    2016-01-01

    Topically applied chemicals may volatilize, or evaporate, from skin leaving behind a chemical residue with new percutaneous absorptive capabilities. Understanding volatilization of topical medications, such as sunscreens, fragrances, insect repellants, cosmetics and other commonly applied topicals may have implications for their safety and efficacy. A systematic review of English language articles from 1979 to 2014 was performed using key search terms. Articles were evaluated to assess the relationship between volatility and percutaneous absorption. A total of 12 articles were selected and reviewed. Key findings were that absorption is enhanced when coupled with a volatile substance, occlusion prevents evaporation and increases absorption, high ventilation increases volatilization and reduces absorption, and pH of skin has an affect on a chemical's volatility. The articles also brought to light that different methods may have an affect on volatility: different body regions; in vivo vs. in vitro; human vs. Data suggest that volatility is crucial for determining safety and efficacy of cutaneous exposures and therapies. Few articles have been documented reporting evaporation in the context of percutaneous absorption, and of those published, great variability exists in methods. Further investigation of volatility is needed to properly evaluate its role in percutaneous absorption.

  1. Basic heat transfer

    CERN Document Server

    Bacon, D H

    2013-01-01

    Basic Heat Transfer aims to help readers use a computer to solve heat transfer problems and to promote greater understanding by changing data values and observing the effects, which are necessary in design and optimization calculations.The book is concerned with applications including insulation and heating in buildings and pipes, temperature distributions in solids for steady state and transient conditions, the determination of surface heat transfer coefficients for convection in various situations, radiation heat transfer in grey body problems, the use of finned surfaces, and simple heat exc

  2. Ideal Heat Exchange System

    Science.gov (United States)

    Tsirlin, A. M.

    2017-09-01

    The requirements with which a heat exchange system should comply in order that at certain values of the total contact surface and heat load the entropy production in it should be minimal have been determined. It has been shown that this system can serve as a standard for real systems of irreversible heat exchange. We have found the conditions for physical realizability of a heat exchange system in which heat exchange occurs by a law linear with respect to the temperature difference between contacting flows. Analogous conditions are given without deriving for the case of heat exchange by the Fourier law.

  3. Microscale Regenerative Heat Exchanger

    Science.gov (United States)

    Moran, Matthew E.; Stelter, Stephan; Stelter, Manfred

    2006-01-01

    The device described herein is designed primarily for use as a regenerative heat exchanger in a miniature Stirling engine or Stirling-cycle heat pump. A regenerative heat exchanger (sometimes called, simply, a "regenerator" in the Stirling-engine art) is basically a thermal capacitor: Its role in the Stirling cycle is to alternately accept heat from, then deliver heat to, an oscillating flow of a working fluid between compression and expansion volumes, without introducing an excessive pressure drop. These volumes are at different temperatures, and conduction of heat between these volumes is undesirable because it reduces the energy-conversion efficiency of the Stirling cycle.

  4. Size-controlled heating ability of CoFe2O4 nanoparticles for hyperthermia applications

    Science.gov (United States)

    Phong, P. T.; Phuc, N. X.; Nam, P. H.; Chien, N. V.; Dung, D. D.; Linh, P. H.

    2018-02-01

    The magnetic properties and heating capacity of cobalt ferrite (CoFe2O4) nanoparticles 13-24 nm in size were studied. Results showed that the specific absorption rate of the nanoparticles strongly depended on their magnetic properties and particle size. Specific absorption rate values decreased with increased particle size, and the smallest CoFe2O4 nanoparticles (13.5 nm) exhibited the highest specific absorption rate. The mechanism underlying the decrease in specific absorption rate of the CoFe2O4 nanoparticles with increased particle size was also discussed.

  5. Cogeneration with gas turbines. Use of heat pipe type exchangers for the energy recuperation of exhausted gases; Cogeracao com turbinas a gas. O uso de trocador tipo tubos de calor (heat pipe) para a recuperacao energetica dos gases de exaustao

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, Jose Luz; Balestieri, Jose A.P.; Tanisho, Petronio Masanobu; Zanardi, Mauricio Araujo; Murcia, Nelson [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia

    1995-07-01

    Gas turbine cogeneration systems are being widely used in the simultaneous production of electricity and useful heat. Several devices can be indicated to the recovery of exhaust gas heat from gas turbine systems, for example heat recovery steam generators, boiling-water heaters, absorption refrigerating systems (cooled water), drying systems (heated air), each one indicated for a specific use of recovery heat. In this paper it is proposed the use of heat pipes exchangers in the recovery of exhaust gas heat to produce heated water to be used in a process. Heat pipes are devices that has high thermal conductance that can be used to reduce thermal losses to the environment. The use of heat pipes in these types of equipment can provide heat recoveries of high efficiency since both fluid flows are external and there are less contamination risks between the hot and cold streams. (author)

  6. Gas treating absorption theory and practice

    CERN Document Server

    Eimer, Dag

    2014-01-01

    Gas Treating: Absorption Theory and Practice provides an introduction to the treatment of natural gas, synthesis gas and flue gas, addressing why it is necessary and the challenges involved.  The book concentrates in particular on the absorption-desorption process and mass transfer coupled with chemical reaction. Following a general introduction to gas treatment, the chemistry of CO2, H2S and amine systems is described, and selected topics from physical chemistry with relevance to gas treating are presented. Thereafter the absorption process is discussed in detail, column hardware is explain

  7. Psychological absorption. Affect investment in marijuana intoxication.

    Science.gov (United States)

    Fabian, W D; Fishkin, S M

    1991-01-01

    Absorption (a trait capacity for total attentional involvement) was reported to increase during episodes of marijuana intoxication. Several subsets of the absorption scale items specifically characterized marijuana intoxication, and groups of users and nonusers showed differential affective involvement with these experiences. Additionally, within the drug-using group, a positive correlation between frequency of marijuana use and affective ratings of these experiences was found. The findings support the hypothesis that a specific type of alteration in consciousness that enhances capacity for total attentional involvement (absorption) characterizes marijuana intoxication, and that this enhancement may act as a reinforcer, possibly influencing future use.

  8. Coherent Absorption of N00N States.

    Science.gov (United States)

    Roger, Thomas; Restuccia, Sara; Lyons, Ashley; Giovannini, Daniel; Romero, Jacquiline; Jeffers, John; Padgett, Miles; Faccio, Daniele

    2016-07-08

    Recent results in deeply subwavelength thickness films demonstrate coherent control and logical gate operations with both classical and single-photon light sources. However, quantum processing and devices typically involve more than one photon and nontrivial input quantum states. Here we experimentally investigate two-photon N00N state coherent absorption in a multilayer graphene film. Depending on the N00N state input phase, it is possible to selectively choose between single- or two-photon absorption of the input state in the graphene film. These results demonstrate that coherent absorption in the quantum regime exhibits unique features, opening up applications in multiphoton spectroscopy and imaging.

  9. HYDRATION PATTERN IN THE HEAT

    Directory of Open Access Journals (Sweden)

    O Hue

    2014-10-01

    Full Text Available To investigate thermal response, hydration behaviour and performance over flatwater kayaking races in tropical conditions (36.8°C and 68 % rh. Five internationally-ranked subjects participated in the 2012 Surfski Ocean Racing World Cup in Guadeloupe to the “Ze Caribbean Race 2012” [i.e., a 35-km downwind race]. Core temperature (T°C and heart rate (HR were measured using portable telemetry units whereas water intake was deduced from backpacks absorption. The kayakers were asked to rate both their comfort sensation and thermal sensation on a scale before and after the race. The performance was related to an increase in T°C, high HR and low water intake (WI; and (2 high values of final T°C were related to high pre T°C and greater increases in T°C being obtained with low pre T°C and (3 WI being related to high pre T°C. The present study demonstrated that the fastest kayakers were those able to paddle at the highest intensities, increasing their T°C and drinking little water without any interference from thermal sensations. Water intake was positively related to pre-race T°C, which reinforces the importance of beginning surfski races with a low T°C. This study demonstrated that well-trained kayakers drinking ad libitum were able to anticipate their intensity/heat storage ratio to prevent heat illness and severe dehydration and maintain high performance.

  10. Integrated reactive absorption process for synthesis of fatty esters.

    Science.gov (United States)

    Kiss, Anton Alexandru; Bildea, Costin Sorin

    2011-01-01

    Reactive separations using green catalysts offer great opportunities for manufacturing fatty esters, involved in specialty chemicals and biodiesel production. Integrating reaction and separation into one unit provides key benefits such as: simplified operation, no waste, reduced capital investment and low operating costs. This work presents a novel heat-integrated reactive absorption process that eliminates all conventional catalyst related operations, efficiently uses the raw materials and equipment, and considerably reduces the energy requirements for biodiesel production--85% lower as compared to the base case. Rigorous simulations based on experimental results were carried out using Aspen Plus and Dynamics. Despite the high degree of integration, the process is well controllable using an efficient control structure proposed in this work. The main results are provided for a plant producing 10 ktpy fatty acid methyl esters from methanol and waste vegetable oil with high free fatty acids content, using sulfated zirconia as solid acid catalyst. Copyright © 2010 Elsevier Ltd. All rights reserved.

  11. CO2 CAPTURE BY ABSORPTION WITH POTASSIUM CARBONATE

    Energy Technology Data Exchange (ETDEWEB)

    Gary T. Rochelle; Eric Chen; J.Tim Cullinane; Marcus Hilliard; Jennifer Lu; Babatunde Oyenekan; Ross Dugas

    2004-07-29

    The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. CO{sub 2} mass transfer rates are second order in piperazine concentration and increase with ionic strength. Modeling of stripper performance suggests that 5 m K{sup +}/2.5 m PZ will require 25 to 46% less heat than 7 m MEA. The first pilot plant campaign was completed on June 24. The CO{sub 2} penetration through the absorber with 20 feet of Flexipac{trademark} 1Y varied from 0.6 to 16% as the inlet CO{sub 2} varied from 3 to 12% CO{sub 2} and the gas rate varied from 0.5 to 3 kg/m{sup 2}-s.

  12. Thermally induced nonlinear optical absorption in metamaterial perfect absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Guddala, Sriram, E-mail: sguddala@iitk.ac.in; Kumar, Raghwendra; Ramakrishna, S. Anantha [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2015-03-16

    A metamaterial perfect absorber consisting of a tri-layer (Al/ZnS/Al) metal-dielectric-metal system with top aluminium nano-disks was fabricated by laser-interference lithography and lift-off processing. The metamaterial absorber had peak resonant absorbance at 1090 nm and showed nonlinear absorption for 600ps laser pulses at 1064 nm wavelength. A nonlinear saturation of reflectance was measured to be dependent on the average laser power incident and not the peak laser intensity. The nonlinear behaviour is shown to arise from the heating due to the absorbed radiation and photo-thermal changes in the dielectric properties of aluminium. The metamaterial absorber is seen to be damage resistant at large laser intensities of 25 MW/cm{sup 2}.

  13. Economical analysis of combined fuel cell generators and absorption chillers

    Directory of Open Access Journals (Sweden)

    M. Morsy El-Gohary

    2013-06-01

    Full Text Available This paper presents a co-generation system based on combined heat and power for commercial units. For installation of a co-generation system, certain estimates for this site should be performed through making assessments of electrical loads, domestic water, and thermal demand. This includes domestic hot water, selection of the type of power generator, fuel cell, and the type of air conditioning system, and absorption chillers. As a matter of fact, the co-generation system has demonstrated good results for both major aspects, economic and environmental. From the environmental point of view, this can be considered as an ideal solution for problems concerned with the usage of Chlorofluoro carbons. On the other hand, from the economic point of view, the cost analysis has revealed that the proposed system saves 4% of total cost through using the co-generation system.

  14. Feasibility of waste heat recovery concepts for geothermal refrigeration and air conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, R.

    1986-01-01

    This paper presents the qualitative feasibility of two waste heat recovery concepts for geothermal refrigeration and air conditioning. The high temperature available at shallow depths of abandoned or dry wells in oil fields and the natural gas which is being flared without any use near oil producing wells, can be used as heat input for vapour absorption cooling systems. Depending upon the quantity and quality of low grade heat from these sources, conventional refrigerant-absorbent combinations, e.g. water-lithium bromide and ammonia-water may be used for refrigeration and air conditioning purposes in the basic vapour absorption systems.

  15. Analysis of advanced conceptual designs for single-family-sized absorption chillers. Annual report

    Energy Technology Data Exchange (ETDEWEB)

    1978-09-27

    The objectives of the research reported is to develop and analyze new concepts for absorption cycles to improve the performance or reduce the cost of a 3-ton absorption chiller that can be used with solar collected heat. New refrigerant-absorbent pairs are investigated, as are additives to currently used refrigerant-absorbent pairs. Results are given of a literature search on those topics. An initial screening is reported to check the values of the heats of mixing of candidate refrigerants and adsorbents, and also to screen several candidate absorbents against water as a refrigerant. A modified apparatus and procedures for measurement of refrigerant-absorbent solubilities are described. Pressure-temperature-composition data for the R-22/E-181 pair were measured. Based on theory and the information found in the literature, a set of criteria and guidelines was developed that gives the desirable properties of the refrigerants, absorbents, and pairs. (LEW)

  16. Thermal changes in the absorption spectra of blood with supravascular infrared laser irradiation in vivo

    Science.gov (United States)

    Zalesskaya, G. A.; Astaf'eva, L. G.; Batai, L. E.

    2011-09-01

    We have studied the effect of laser radiation (λ = 1960 nm, power density from 6 to 25 W/cm2) on the absorption spectra of rat blood with supravascular irradiation. We have established that absorption of laser radiation leads to a decrease in the degree of oxygen saturation of mixed venous blood due to its heating. We have estimated the initial heating temperatures of venous blood and the surface of the irradiated tissue using an optothermal model, taking into account the characteristics of the laser radiation and the optical and thermal characteristics of the biological tissue. We consider the effect of radiation-induced thermal dissociation of oxyhemoglobin on the oxygen transport characteristics of the blood and metabolic processes.

  17. Moisture absorption and bakeout characteristics of rigid-flexible multilayer printed wiring boards

    Energy Technology Data Exchange (ETDEWEB)

    Lula, J.W.

    1991-01-01

    Moisture absorption and bakeout characteristics of Allied-Signal Inc., Kansas City Division (KCD) rigid-flexible printed wiring boards were determined. It was found that test specimens had absorbed 0.95 weight percent moisture when equilibrated to a 50 percent RH, 25{degree}C environment. Heating those equilibrated specimens in a 120{degree}C static air oven removed 92 percent of this absorbed moisture in 24 h. Heating the samples in a 80{degree}C static air oven removed only 64 percent of the absorbed moisture at the end of 24 h. A 120{degree}C vacuum bake removed moisture at essentially the same rate with parylene slowed the absorption rate by approximately 50 percent but did not appreciably affect the equilibrium moisture content or the drying rate.

  18. Nonlinear Absorptions of CdSeTe Quantum Dots under Ultrafast Laser Radiation

    Directory of Open Access Journals (Sweden)

    Zhijun Chai

    2016-01-01

    Full Text Available The oil-soluble alloyed CdSeTe quantum dots (QDs are prepared by the electrostatic method. The basic properties of synthesized CdSeTe QDs are characterized by UV-Vis absorption spectroscopy, photoluminescence spectroscopy, inductively coupled plasma mass spectrometry, and transmission electron microscope. The off-resonant nonlinear optical properties of CdSeTe QDs are studied by femtosecond Z-scan at 1 kHz (low-repetition rate and 84 MHz (high-repetition rate. Nonlinear absorption coefficients are calculated under different femtosecond laser excitations. Due to the long luminescent lifetime of CdSeTe QDs, under the conditions of high-repetition rate, for open-aperture curve, heat accumulation and bleaching of ground state are responsible for the decrease of two-photon absorption (TPA coefficient.

  19. Temperature effect on nitrogen-induced absorption of oxygen in the Herzberg continuum

    Science.gov (United States)

    Shardanand, MR.

    1978-01-01

    The effect of temperature on the total absorption of O2 induced by collisions with N2 has been measured at various temperatures in the Herzberg continuum using a one-meter normal-incidence grating monochromator. It is observed that absorption increases as the temperature decreases, which is ascribed to changes in the rate of formation of the dimers O2-O2 and O2-N2. The interaction constants for these dimers are determined as functions of temperature and then utilized to calculate the heats of dissociation of O2-O2 and O2-N2. Their respective values are found to be 0.0146 + or - 0.001 and 0.425 + or - 0.002 eV. Also, the interaction constants for these dimers measured at 200 + or - 1 K are utilized to investigate their effect on the absorption of solar radiation in the stratosphere.

  20. Sound, infrasound, and sonic boom absorption by atmospheric clouds.

    Science.gov (United States)

    Baudoin, Michaël; Coulouvrat, François; Thomas, Jean-Louis

    2011-09-01

    This study quantifies the influence of atmospheric clouds on propagation of sound and infrasound, based on an existing model [Gubaidulin and Nigmatulin, Int. J. Multiphase Flow 26, 207-228 (2000)]. Clouds are considered as a dilute and polydisperse suspension of liquid water droplets within a mixture of dry air and water vapor, both considered as perfect gases. The model is limited to low and medium altitude clouds, with a small ice content. Four physical mechanisms are taken into account: viscoinertial effects, heat transfer, water phase changes (evaporation and condensation), and vapor diffusion. Physical properties of atmospheric clouds (altitude, thickness, water content and droplet size distribution) are collected, along with values of the thermodynamical coefficients. Different types of clouds have been selected. Quantitative evaluation shows that, for low audible and infrasound frequencies, absorption within clouds is several orders of magnitude larger than classical absorption. The importance of phase changes and vapor diffusion is outlined. Finally, numerical simulations for nonlinear propagation of sonic booms indicate that, for thick clouds, attenuation can lead to a very large decay of the boom at the ground level. © 2011 Acoustical Society of America

  1. Modeling Broadband X-Ray Absorption of Massive Star Winds

    Science.gov (United States)

    Leutenegger, Maurice A.; Cohen,David H.; Zsargo, Janos; Martell, Erin M.; MacArthur, James P.; Owocki, Stanley P.; Gagne, Marc; Hillier, D. John

    2010-01-01

    We present a method for computing the net transition of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral ISM tabulation. Preliminary modeling of Chandra grating data indicates that the X-ray hardness trend of OB stars with spectral subtype cars largely be understood as a wind absorption effect.

  2. Absorption fluids data survey: Final report on foreign data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Gutraj, J.M.; Zawacki, T.S.

    1987-04-01

    In a 12-month evaluation, 300 different foreign publications containing data that relate to properties of binary, ternary, and multicomponent absorption fluids were identified; from these publications, 127 were selected as sources of relevant foreign data. Fluids covered include combinations of each of 20 different refrigerant compounds, with one or more of 41 single, 13 binary, and 6 ternary absorbent compounds. Generally, the 20 refrigerants are divided among the following categories of chemical compounds - INORGANIC 2, ORGANIC 18 (amines 2, alcohols 5, halogenated 10 and hydrocarbons 1). Likewise, the single absorbent compounds generally are subdivided as follows - INORGANIC 11, ORGANIC 30 (alcohols 7, ethers 4, alcohol-ethers 1, amides 2, amines 1, esters 7, ketones 2, acids 1 and others 5). The binary and ternary absorbents are various mixtures of two or more single absorbent compounds. Coarse screening and evaluations were performed. Data gaps for key fluids are summarized and unresolved conflicts in data are noted. Results show that with very few exceptions, all candidate fluids for development activities dealing with advanced absorption heat pump concepts have data gaps that must be addressed in the near future.

  3. Absorption fluids data survey: Final report on worldwide data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Gutraj, J.M.; Zawacki, T.S.

    1988-02-01

    Over 500 different worldwide publications containing data that relate to properties of binary, ternary, and multicomponent absorption fluids have been identified; from these publications, 278 were selected as primary sources of relevant data. Fluids covered include combinations of 38 different refrigerant compounds, as well as of 131 single, 42 binary, and 14 ternary absorbent compounds. Generally, the 38 refrigerants are divided among the following categories of chemical compounds: inorganic, 3; organic, 35 (amines, 4; alcohols, 5; halogenated, 25; and hydrocarbons, 1). The single absorbent compounds generally are subdivided as follows: inorganic, 48; organic, 83 (alcohols, 10; ethers, 5; alcohol-ethers, 3; amides, 9; amines, 4; amine-alcohols, 1; esters, 21; ketones, 5; acids, 4; aldehydes, 1; and others, 20). The binary and ternary absorbents are various mixtures of two or more single absorbent compounds. Coarse screening and evaluations were performed. Data gaps for key fluids are summarized and unresolved conflicts in data are noted. Results show that, with very few exceptions, all candidate fluids for development activities dealing with advanced absorption heat pump concepts have data gaps that must be addressed in the near future. 44 figs., 6 tabs.

  4. Absorption fluids data survey: final report on USA data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S.

    1986-05-01

    In an 8-month evaluation, 150 different US publications containing data that relate to properties of binary, ternary, and multicomponent absorption fluids were identified; from these publications, 67 were selected as primary sources of relevant US data. Fluids covered include combinations of 25 different refrigerant compounds, as well as of 67 single, 30 binary, and 4 ternary absorbent compounds. Generally, the 25 refrigerants are divided among the following categories of chemical compounds - INORGANIC 3, ORGANIC 22 (amines 3, alcohols 3, halogenated 16). Likewise, the single absorbent compounds generally are subdivided as follows - INORGANIC 31, ORGANIC 48 (alcohols 6, ethers 5, alcohol-ethers 2, amines 8, amines 3, amine-alcohol 1, esters 9, ketones 5, acids 3, aldehyde 1, others 4). The binary and ternary absorbents are various mixtures of two or more single absorbent compounds. Coarse screening and evaluations were performed. Data gaps for key fluids are summarized and unresolved conflicts in data are noted. Results show that, with very few exceptions, all candidate fluids for development activities dealing with advanced absorption heat pump concepts have data gaps that must be addressed in the near future.

  5. Studies on Steam Absorption Chillers Performance at a Cogeneration Plant

    Directory of Open Access Journals (Sweden)

    Abd Majid Mohd Amin

    2014-07-01

    Full Text Available Absorption chillers at cogeneration plants generate chilled water using steam supplied by heat recovery steam generators. The chillers can be of either single-effect or double effect configuration and the coefficient of performance (COP depends on the selection made. The COP varies from 0.7 to 1.2 depending on the types of chillers. Single effect chillers normally have COP in the range of 0.68 to 0.79. Double effect chillers COP are higher and can reach 1.2. However due to factors such as inappropriate operations and maintenance practices, COP could drop over a period of time. In this work the performances of double effect steam absorption chillers at a cogeneration plant were studied. The study revealed that during the period of eleven years of operation the COP of the chillers deteriorated from 1.25 to 0.6. Regression models on the operation data indicated that the state of deterioration was projected to persist. Hence, it would be recommended that the chillers be considered for replacement since they had already undergone a series of costly repairs.

  6. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... Be Prepared Safe Citizen Day Organize Important Medical Information ER Checklists Preparing for Emergencies Be ready to ... anyone can be affected. Here you will find information about heat cramps and heat stroke and exhaustion. ...

  7. Heat Roadmap Europe

    DEFF Research Database (Denmark)

    David, Andrei; Mathiesen, Brian Vad; Averfalk, Helge

    2017-01-01

    The Heat Roadmap Europe (HRE) studies estimated a potential increase of the district heating (DH) share to 50% of the entire heat demand by 2050, with approximately 25–30% of it being supplied using large-scale electric heat pumps. This study builds on this potential and aims to document...... that such developments can begin now with technologies currently available. We present a database and the status of the technology and its ability of expansion to other European locations by reviewing experiences aimed at further research or application in the heating industry. This is based on a survey of the existing...... capacity of electric large-scale heat pumps with more than 1 MW thermal output, operating in European DH systems. The survey is the first database of its kind containing the technical characteristics of these heat pumps, and provides the basis for the analysis of this paper. By quantifying the heat sources...

  8. Convective heat transfer

    CERN Document Server

    Kakac, Sadik; Pramuanjaroenkij, Anchasa

    2014-01-01

    Intended for readers who have taken a basic heat transfer course and have a basic knowledge of thermodynamics, heat transfer, fluid mechanics, and differential equations, Convective Heat Transfer, Third Edition provides an overview of phenomenological convective heat transfer. This book combines applications of engineering with the basic concepts of convection. It offers a clear and balanced presentation of essential topics using both traditional and numerical methods. The text addresses emerging science and technology matters, and highlights biomedical applications and energy technologies. What’s New in the Third Edition: Includes updated chapters and two new chapters on heat transfer in microchannels and heat transfer with nanofluids Expands problem sets and introduces new correlations and solved examples Provides more coverage of numerical/computer methods The third edition details the new research areas of heat transfer in microchannels and the enhancement of convective heat transfer with nanofluids....

  9. Heat resistant microorganism

    NARCIS (Netherlands)

    Berendsen, Erwin M.; Bennik, Maria H.J.; Kuipers, Oscar

    2015-01-01

    The invention relates to a kit and methods and means for the determination of the presence of heat resistant organisms. The invention further relates to the provision organisms wherein the heat resistance is modulated.

  10. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... heat stroke and exhaustion. Heat Cramps Symptoms include muscle spasms, usually in the legs and stomach area. ... Z Teeth (Dental Emergencies) Sprains and Strains Head Injury Resources Home Safety Checklist ACEP Coloring Book Download ...

  11. Heating patterns produced by shortwave diathermy applicators in tissue substitute models.

    Science.gov (United States)

    Lehmann, J F; McDougall, J A; Guy, A W; Warren, C G; Esselman, P C

    1983-12-01

    To be a deep-heating modality, shortwave diathermy applicators have to heat the musculature more than the subcutaneous fat. In this study, commercially available and prototype shortwave diathermy applicators were tested using tissue substitute models which allow rapid thermographic scanning of the initial linear transient temperature rise in the subcutaneous fat and muscle. The specific absorption rates (SAR) of the electromagnetic radiation were calculated throughout the tissues. Great differences were found in the deep-heating capability of these applicators. Some of the applicators heated the subcutaneous fat more than the muscle, while others were more efficient in heating the musculature.

  12. Connecting X-ray absorption and 21 cm neutral hydrogen absorption in obscured radio AGN

    Science.gov (United States)

    Moss, V. A.; Allison, J. R.; Sadler, E. M.; Urquhart, R.; Soria, R.; Callingham, J. R.; Curran, S. J.; Musaeva, A.; Mahony, E. K.; Glowacki, M.; Farrell, S. A.; Bannister, K. W.; Chippendale, A. P.; Edwards, P. G.; Harvey-Smith, L.; Heywood, I.; Hotan, A. W.; Indermuehle, B. T.; Lenc, E.; Marvil, J.; McConnell, D.; Reynolds, J. E.; Voronkov, M. A.; Wark, R. M.; Whiting, M. T.

    2017-11-01

    Many radio galaxies show the presence of dense and dusty gas near the active nucleus. This can be traced by both 21 cm H I absorption and soft X-ray absorption, offering new insight into the physical nature of the circumnuclear medium of these distant galaxies. To better understand this relationship, we investigate soft X-ray absorption as an indicator for the detection of associated H I absorption, as part of preparation for the First Large Absorption Survey in H I to be undertaken with the Australian Square Kilometre Array Pathfinder (ASKAP). We present the results of our pilot study using the Boolardy Engineering Test Array, a precursor to ASKAP, to search for new absorption detections in radio sources brighter than 1 Jy that also feature soft X-ray absorption. Based on this pilot survey, we detected H I absorption towards the radio source PKS 1657-298 at a redshift of z = 0.42. This source also features the highest X-ray absorption ratio of our pilot sample by a factor of 3, which is consistent with our general findings that X-ray absorption predicates the presence of dense neutral gas. By comparing the X-ray properties of active galactic nuclei with and without detection of H I absorption at radio wavelengths, we find that X-ray hardness ratio and H I absorption optical depth are correlated at a statistical significance of 4.71σ. We conclude by considering the impact of these findings on future radio and X-ray absorption studies.

  13. Heat storage for a bus petrol internal-combustion engine

    Science.gov (United States)

    Vasiliev, Leonard L.; Burak, Victor S.; Kulakov, Andry G.; Mishkinis, Donatas A.; Bohan, Pavel V.

    The heat storage (HS) system for pre-heating a bus petrol internal combustion engine to starting was mathematically modelled and experimentally investigated. The development of such devices is an extremely urgent problem especially for regions with a cold climate. We discuss how HS works on the effect of absorption and rejection of heat energy at a solid-liquid phase change of a HS substance. In the first part of the paper a numerical method to calculate the HS mass-dimensional parameters and their characteristics are described. In the experimental part of the paper results are given of experiments on the pre-heating device aiding to start a carburettor engine under operational conditions and analysis of data received. Practical confirmation of the theoretical development of HS devices for a bus engine for starting by pre-heating is given.

  14. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    Energy Technology Data Exchange (ETDEWEB)

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  15. ONE OF THE WAYS TO RISE THE EFFICIENCY OF THE KISHINEV TOWN HEAT AND POWER STATIONS

    Directory of Open Access Journals (Sweden)

    Maximuk E.P.

    2010-04-01

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

  16. Vapor Jet Ejector Used to Generate Free Waste Heat Driven Cooling in Military Environmental Cooling Units

    Science.gov (United States)

    2012-07-01

    2164, Page 1 International Refrigeration and Air Conditioning Conference at Purdue, July 16-19, 2012 Vapor Jet Ejector Used to Generate Free...heat driven vapor jet ejector cooling cycle is a very promising approach to produce ‘free’ cooling by utilizing low-grade energy sources. The...mechanism behind ejector -based waste heat cooling is very different from absorption or adsorption cooling technologies that are also aimed at producing heat

  17. Heat generation in laser irradiated tissue.

    Science.gov (United States)

    Welch, A J; Pearce, J A; Diller, K R; Yoon, G; Cheong, W F

    1989-02-01

    Many medical applications involving lasers rely upon the generation of heat within the tissue for the desired therapeutic effect. Determination of the absorbed light energy in tissue is difficult in many cases. Although UV wavelengths of the excimer laser and 10.6 microns wavelength of the CO2 laser are absorbed within the first 20 microns of soft tissue, visible and near infrared wavelengths are scattered as well as absorbed. Typically, multiple scattering is a significant factor in the distribution of light in tissue and the resulting heat source term. An improved model is presented for estimating heat generation due to the absorption of a collimated (axisymmetric) laser beam and scattered light at each point r and z in tissue. Heat generated within tissue is a function of the laser power, the shape and size of the incident beam and the optical properties of the tissue at the irradiation wavelength. Key to the calculation of heat source strength is accurate estimation of the light distribution. Methods for experimentally determining the optical parameters of tissue are discussed in the context of the improved model.

  18. The Near-infrared CO Absorption Band as a Probe to the Innermost Part of an AGN-obscuring Material

    Science.gov (United States)

    Baba, Shunsuke; Nakagawa, Takao; Isobe, Naoki; Shirahata, Mai

    2018-01-01

    We performed a systematic analysis of the 4.67 μm CO ro-vibrational absorption band toward nearby active galactic nuclei (AGNs) and analyzed the absorption profiles of 10 nearby galaxies collected from the AKARI and Spitzer spectroscopic observations that show the CO absorption feature by fitting a plane-parallel local thermal equilibrium gas model. We found that CO gas is warm (200–500 K) and has a large column density ({N}{{H}}≳ {10}23 {{cm}}-2). The heating of the gas is not explicable by either UV heating or shock heating because these processes cannot represent the large column densities of the warm gas. Instead, X-ray photons from the nuclei, which can produce large columns of warm gas with up to {N}{{H}}∼ {10}24 {{cm}}-2, are the most convincing power source. The hydrogen column density estimated from the CO band is smaller than that inferred from X-ray observations. These results indicate that the region probed by the near-infrared CO absorption is in the vicinity of the nuclei and is located outside the X-ray emitting region. Furthermore, the covering factors of nearly unity required by the observed deep absorption profiles suggest that the probed region is close to the continuum source, which can be designated as the inner rim of the obscuring material around the AGN.

  19. Gintonin absorption in intestinal model systems

    Directory of Open Access Journals (Sweden)

    Byung-Hwan Lee

    2018-01-01

    Conclusion: The present study shows that gintonin could be absorbed in the intestine through transcellular and paracellular diffusion, and active transport. In addition, the lipid component of gintonin might play a key role in its intestinal absorption.

  20. Multiphoton absorption in amyloid protein fibres

    Science.gov (United States)

    Hanczyc, Piotr; Samoc, Marek; Norden, Bengt

    2013-12-01

    Fibrillization of peptides leads to the formation of amyloid fibres, which, when in large aggregates, are responsible for diseases such as Alzheimer's and Parkinson's. Here, we show that amyloids have strong nonlinear optical absorption, which is not present in native non-fibrillized protein. Z-scan and pump-probe experiments indicate that insulin and lysozyme β-amyloids, as well as α-synuclein fibres, exhibit either two-photon, three-photon or higher multiphoton absorption processes, depending on the wavelength of light. We propose that the enhanced multiphoton absorption is due to a cooperative mechanism involving through-space dipolar coupling between excited states of aromatic amino acids densely packed in the fibrous structures. This finding will provide the opportunity to develop nonlinear optical techniques to detect and study amyloid structures and also suggests that new protein-based materials with sizable multiphoton absorption could be designed for specific applications in nanotechnology, photonics and optoelectronics.

  1. The Driving Forces of Subsidiary Absorptive Capacity

    DEFF Research Database (Denmark)

    Schleimer, Stephanie C.; Pedersen, Torben

    2013-01-01

    capacity in order to compete in its focal market. The dual embeddedness of MNC subsidiaries plays a key role in this investigation, as subsidiaries belong to the MNC network and are simultaneously embedded in their host country environment. We argue that subsidiary absorptive capacity is formed...... as a purposeful response to this dual embeddedness. An analysis of marketing strategy absorptions undertaken by 213 subsidiaries reveals that MNCs can assist their subsidiaries to compete in competitive and dynamic focal markets by forming specific organizational mechanisms that are conducive to the development......The study investigates how a multinational corporation (MNC) can promote the absorptive capacity of its subsidiaries. The focus is on what drives the MNC subsidiary's ability to absorb marketing strategies that are initiated by the MNC parent, as well as how the subsidiary enacts on this absorptive...

  2. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a highly sensitive and compact monitor to measure light absorption from particulate matters. The fundamental of the proposed device is based on...

  3. Extending Organizational Antecedents Of Absorptive Capacity

    DEFF Research Database (Denmark)

    Burcharth, Ana Luiza de Araújo; Lettl, Christopher; Ulhøi, John Parm

    2015-01-01

    on organizational characteristics that encourage experimentation. Specifically, we argue that characteristics such as slack resources, tolerance for failure, willingness to cannibalize and external openness are important organizational antecedents for knowledge absorption activities as they prevent inertia. Drawing...

  4. Isolated quantum heat engine.

    Science.gov (United States)

    Fialko, O; Hallwood, D W

    2012-02-24

    We present a theoretical and numerical analysis of a quantum system that is capable of functioning as a heat engine. This system could be realized experimentally using cold bosonic atoms confined to a double well potential that is created by splitting a harmonic trap with a focused laser. The system shows thermalization, and can model a reversible heat engine cycle. This is the first demonstration of the operation of a heat engine with a finite quantum heat bath.

  5. Isolated quantum heat engine

    OpenAIRE

    Fialko, O.; Hallwood, D.

    2011-01-01

    We present a theoretical and numerical analysis of a quantum system that is capable of functioning as a heat engine. This system could be realized experimentally using cold bosonic atoms confined to a double well potential that is created by splitting a harmonic trap with a focused laser. The system shows thermalization, and can model a reversible heat engine cycle. This is the first demonstration of the operation of a heat engine with a finite quantum heat bath.

  6. Solar heat receiver

    Science.gov (United States)

    Hunt, Arlon J.; Hansen, Leif J.; Evans, David B.

    1985-01-01

    A receiver for converting solar energy to heat a gas to temperatures from 700.degree.-900.degree. C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

  7. Ultraviolet absorption cross sections of hydrogen peroxide

    Science.gov (United States)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  8. Water Absorption Behavior of Hemp Hurds Composites

    OpenAIRE

    Nadezda Stevulova; Julia Cigasova; Pavol Purcz; Ivana Schwarzova; Frantisek Kacik; Anton Geffert

    2015-01-01

    In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion) and long-term (up to 180 days) water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp an...

  9. Systemic Absorption of Nanomaterials by Oral Exposure

    DEFF Research Database (Denmark)

    Binderup, Mona-Lise; Bredsdorff, Lea; Beltoft, Vibe Meister

    This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches.......This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches....

  10. Enhancement of Kerr nonlinearity completely without absorption

    Science.gov (United States)

    Liang, Hong; Niu, Yueping; Deng, Li; Gong, Shangqing

    2017-12-01

    We investigate the enhancement of the Kerr nonlinearity in a four-level tripod-type atomic system completely without absorption. We study the effect of the incoherent pumping on the nonlinear susceptibility of the probe field and show that compared with that without the incoherent pumping, the Kerr nonlinearity can be enhanced with completely suppressed absorption at two different probe frequencies. Thus, we can get a symmetrical enhanced Kerr nonlinearity. Particularly, all of our results are in the case of Doppler broadening.

  11. The Automation of Sound Absorption Coefficient Measurement

    OpenAIRE

    Hermawanto, Denny; Suwandi, Achmad

    2006-01-01

    By manual method, the sound absorption coefficient measurement should be done by utilizing many type of equipment such as: measuring amplifier, level recorder, band-pass filter, protactor, etc. However it caused inefficient and need longer time in processing measurement data, therefore the automation system of sound absorption coefficient has been realized. An acoustical real time analyzer type B&K 2144 has been used to record the decay of sound pressure level, thus the processing data is dri...

  12. Morphology of Southern Hemisphere Riometer Auroral Absorption

    Science.gov (United States)

    2006-06-01

    Departamento de Geofísica Universidad de Concepción, Concepción CHILE foppiano@udec.cl ABSTRACT A morphology of riometer auroral absorption is...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Departamento de Geofísica Universidad de...UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED MORPHOLOGY OF SOUTHERN HEMISPHERE RIOMETER AURORAL ABSORPTION Alberto J. Foppiano Departamento de

  13. Heavy ion irradiation effects of polymer film on absorption of light

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Noboru; Seguchi, Tadao [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Arakawa, Tetsuhito

    1997-03-01

    Ion irradiation effects on the absorption of light for three types of polymer films; polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN), and polyether-ether-ketone (PEEK) were investigated by irradiation of heavy ions with Ni{sup 4+}(15MeV), O{sup 6+}(160MeV), and Ar{sup 8+}(175MeV), and compared with electron beams(EB) irradiation. The change of absorption at 400nm by a photometer was almost proportional to total dose for ions and EB. The absorption per absorbed dose was much high in Ni{sup 4+}, but rather small in O{sup 6+} and Ar{sup 8+} irradiation, and the absorption by EB irradiation was accelerated by the temperature of polymer film during irradiation. The beam heating of materials during ion irradiation was assumed, especially for Ni ion irradiation. The heavy ion irradiation effect of polymers was thought to be much affected by the ion beam heating than the linear energy transfer(LET) of radiation source. (author)

  14. Carbon-Nanohorn Based Nanofluids for a Direct Absorption Solar Collector for Civil Application.

    Science.gov (United States)

    Moradi, A; Sani, E; Simonetti, M; Francini, F; Chiavazzo, E; Asinari, P

    2015-05-01

    Direct solar absorption has been often considered in the past as a possible solution for solar thermal collectors for residential and small commercial applications. A direct absorption could indeed improve the performance of solar collectors by skipping one step of the heat transfer mechanism in standard devices and having a more convenient temperature distribution inside the collector. Classical solar thermal collectors have a metal sheet as absorber, designed such that water has the minimum temperature in each transversal section, in order to collect as much solar thermal energy as possible. On the other hand, in a direct configuration, the hottest part of the system is the operating fluid and this allows to have a more efficient conversion. Nanofluids, i.e., fluids with a suspension of nanoparticles, such as carbon nanohorns, could be a good and innovative family of absorbing fluids owing to their higher absorption coefficient compared to the base fluid and stability under moderate temperature gradients. Moreover, carbon nanohorns offer the remarkable advantage of a reduced toxicity over other carbon nanoparticles. In this work, a three-dimensional model of the absorption phenomena in nanofluids within a cylindrical tube is coupled with a computational fluid dynamics (CFD) analysis of the flow and temperature field. Measured optical properties of nanofluids at different concentrations have been implemented in the model. Heat losses due to conduction, convection and radiation at the boundaries are considered as well.

  15. Variations in the spectral values of specific absorption of phytoplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Sathyendranath, S.; Lazzara, L.; Prieur, L.

    Absorption spectra of laboratory cultures of eight species of phytoplankton were studied. These spectra, normalized per unit of chlorophyll a concentration (specific absorption) show variability in magnitude and spectral form. Specific absorption...

  16. Heat-Related Illnesses

    Science.gov (United States)

    ... this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at Mercy Health System in Chesterfield, Missouri Heat-related illness can be caused by overexposure to the sun or any situation that involves extreme heat. Young children and the elderly are most at risk, ...

  17. Heat-Related Illnesses

    Medline Plus

    Full Text Available ... this! Home » Emergency 101 Heat-Related Illnesses Dr. Glenn Mitchell , Emergency physician at Mercy Health System in Chesterfield, Missouri Heat-related illness can be caused by overexposure to the sun or any situation that involves extreme heat. Young children and the elderly are most at risk, ...

  18. Heat roadmap China

    DEFF Research Database (Denmark)

    Xiong, Weiming; Wang, Yu; Mathiesen, Brian Vad

    2015-01-01

    District heating is regarded as a key element of energy saving actions in the Chinese national energy strategy, while space heating in China is currently still dominated by coal boilers. However, there is no existing quantitative study to analyse the future heat strategy for China. Therefore...

  19. Microwave processing heats up

    Science.gov (United States)

    Microwaves are a common appliance in many households. In the United States microwave heating is the third most popular domestic heating method food foods. Microwave heating is also a commercial food processing technology that has been applied for cooking, drying, and tempering foods. It's use in ...

  20. Single Electrode Heat Effects

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Broers, G. H. J.

    1977-01-01

    The heat evolution at a single irreversibly working electrode is treated onthe basis of the Brønsted heat principle. The resulting equation is analogous to the expression for the total heat evolution in a galvanic cellwith the exception that –DeltaS is substituted by the Peltier entropy, Delta...