WorldWideScience

Sample records for satellite refrigerator heat

  1. The APL Satellite Refrigerator Program.

    Science.gov (United States)

    1981-07-01

    36: Fotonic sensor fibers................................ 72 Fig. 37: Vibration levels for S/N 4.......................... 73L Fig. 38: Displacers of...available. This was later achieved by using a Fotonic sensor. 70 The noise level was measured by placing an operating unit in the center of a room...with the refrigerator in operation. To measure this displacement, a Fotonic sensor was mounted on an independent surface with the sensor probe

  2. Sorption Refrigeration / Heat Pump Cycles

    Science.gov (United States)

    Saha, Bidyut Baran; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    Over the past few decades there have been considerable efforts to use adsorption (solid/vapor) for cooling and heat pump applications, but intensified efforts were initiated only since the imposition of international restrictions on the production and use of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons). Up to now, only the desiccant evaporative cooling system of the open type has achieved commercial use, predominantly in the United States. Closed-type adsorption refrigeration and heat pump systems are rarely seen in the market, or are still in the laboratory testing stage. Promising recent development have been made in Japan for the use of porous metal hydrides and composite adsorbents. In this paper, a short description of adsorption theories along with an overview of present status and future development trends of thermally powered adsorption refrigeration cycles are outlined putting emphasis on experimental achievements. This paper also addressed some advanced absorption cycles having relatively higher COP, and also summarizes fundamental concepts of GAX cycles and various GAX cycles developed for heat pump applications.

  3. Refrigerant charge management in a heat pump water heater

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jie; Hampton, Justin W.

    2016-07-05

    Heat pumps that heat or cool a space and that also heat water, refrigerant management systems for such heat pumps, and methods of managing refrigerant charge. Various embodiments remove idle refrigerant from a heat exchanger that is not needed for transferring heat by opening a refrigerant recovery valve and delivering the idle refrigerant from the heat exchanger to an inlet port on the compressor. The heat exchanger can be isolated by closing an electronic expansion valve, actuating a refrigerant management valve, or both. Refrigerant charge can be controlled by controlling how much refrigerant is drawn from the heat exchanger, by letting some refrigerant back into the heat exchanger, or both. Heat pumps can be operated in different modes of operation, and various components can be interconnected with refrigerant conduit. Some embodiments deliver refrigerant gas to the heat exchanger and drive liquid refrigerant out prior to isolating the heat exchanger.

  4. Heat driven refrigeration cycle at low temperatures

    Institute of Scientific and Technical Information of China (English)

    HE Yijian; HONG Ronghua; CHEN Guangming

    2005-01-01

    Absorption refrigeration cycle can be driven by low-grade thermal energy, such as solar energy, geothermal energy and waste heat. It is beneficial to save energy and protect environment. However, the applications of traditional absorption refrigeration cycle are greatly restricted because they cannot achieve low refrigeration temperature. A new absorption refrigeration cycle is investigated in this paper, which is driven by low-grade energy and can get deep low refrigeration temperature. The mixture refrigerant R23+R134a and an absorbent DMF are used as its working fluid. The theoretical results indicate that the new cycle can achieve -62℃ refrigeration temperature when the generation temperature is only 160℃. This refrigeration temperature is much lower than that obtained by traditional absorption refrigeration cycle. Refrigeration temperature of -47.3℃ has been successfully achieved by experiment for this new cycle at the generation temperature of 157℃, which is the lowest temperature obtained by absorption refrigeration system reported in the literature up to now. The theoretical and experimental results prove that new cycle can achieve rather low refrigeration temperature.

  5. Mountain Plains Learning Experience Guide: Heating, Refrigeration, & Air Conditioning.

    Science.gov (United States)

    Carey, John

    This Heating, Refrigeration, and Air Conditioning course is comprised of eleven individualized units: (1) Refrigeration Tools, Materials, and Refrigerant; (2) Basic Heating and Air Conditioning; (3) Sealed System Repairs; (4) Basic Refrigeration Systems; (5) Compression Systems and Compressors; (6) Refrigeration Controls; (7) Electric Circuit…

  6. Boiling Heat Transfer to Halogenated Hydrocarbon Refrigerants

    Science.gov (United States)

    Yoshida, Suguru; Fujita, Yasunobu

    The current state of knowledge on heat transfer to boiling refrigerants (halogenated hydrocarbons) in a pool and flowing inside a horizontal tube is reviewed with an emphasis on information relevant to the design of refrigerant evaporators, and some recommendations are made for future research. The review covers two-phase flow pattern, heat transfer characteristics, correlation of heat transfer coefficient, influence of oil, heat transfer augmentation, boiling from tube-bundle, influence of return bend, burnout heat flux, film boiling, dryout and post-dryout heat transfer.

  7. Waste Heat Recapture from Supermarket Refrigeration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A [ORNL

    2011-11-01

    The objective of this project was to determine the potential energy savings associated with improved utilization of waste heat from supermarket refrigeration systems. Existing and advanced strategies for waste heat recovery in supermarkets were analyzed, including options from advanced sources such as combined heat and power (CHP), micro-turbines and fuel cells.

  8. Refrigeration Playbook. Heat Reclaim; Optimizing Heat Rejection and Refrigeration Heat Reclaim for Supermarket Energy Conservation

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Chuck [CTA Architects Engineers, Boise, ID (United States); Nelson, Eric [CTA Architects Engineers, Boise, ID (United States); Armer, James [CTA Architects Engineers, Boise, ID (United States); Johnson, Tim [CTA Architects Engineers, Boise, ID (United States); Hirsch, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Doebber, Ian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    The purpose of this playbook and accompanying spreadsheets is to generalize the detailed CBP analysis and to put tools in the hands of experienced refrigeration designers to evaluate multiple applications of refrigeration waste heat reclaim across the United States. Supermarkets with large portfolios of similar buildings can use these tools to assess the impact of large-scale implementation of heat reclaim systems. In addition, the playbook provides best practices for implementing heat reclaim systems to achieve the best long-term performance possible. It includes guidance on operations and maintenance as well as measurement and verification.

  9. Quantum heat engines and refrigerators: continuous devices.

    Science.gov (United States)

    Kosloff, Ronnie; Levy, Amikam

    2014-01-01

    Quantum thermodynamics supplies a consistent description of quantum heat engines and refrigerators up to a single few-level system coupled to the environment. Once the environment is split into three (a hot, cold, and work reservoir), a heat engine can operate. The device converts the positive gain into power, with the gain obtained from population inversion between the components of the device. Reversing the operation transforms the device into a quantum refrigerator. The quantum tricycle, a device connected by three external leads to three heat reservoirs, is used as a template for engines and refrigerators. The equation of motion for the heat currents and power can be derived from first principles. Only a global description of the coupling of the device to the reservoirs is consistent with the first and second laws of thermodynamics. Optimization of the devices leads to a balanced set of parameters in which the couplings to the three reservoirs are of the same order and the external driving field is in resonance. When analyzing refrigerators, one needs to devote special attention to a dynamical version of the third law of thermodynamics. Bounds on the rate of cooling when Tc→0 are obtained by optimizing the cooling current. All refrigerators as Tc→0 show universal behavior. The dynamical version of the third law imposes restrictions on the scaling as Tc→0 of the relaxation rate γc and heat capacity cV of the cold bath.

  10. Significance of the non-aceatropic binary refrigerants, when used in heat pumps and refrigeration plants

    Energy Technology Data Exchange (ETDEWEB)

    Kruse, H.; Jakobs, R. (Hannover Univ. (Germany, F.R.). Abt. Kaeltetechnik)

    1977-01-01

    The use of binary refrigerants in refrigerating systems and heat pumps is more economical than the use of conventional refrigerants. They are particularly suitable for heat pumps. This is illustrated by a a test plant in the basis of thermodynamic cycles and properties.

  11. Literature survey of heat transfer enhancement techniques in refrigeration applications

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, M.K.; Shome, B. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

    1994-05-01

    A survey has been performed of the technical and patent literature on enhanced heat transfer of refrigerants in pool boiling, forced convection evaporation, and condensation. Extensive bibliographies of the technical literature and patents are given. Many passive and active techniques were examined for pure refrigerants, refrigerant-oil mixtures, and refrigerant mixtures. The citations were categorized according to enhancement technique, heat transfer mode, and tube or shell side focus. The effects of the enhancement techniques relative to smooth and/or pure refrigerants were illustrated through the discussion of selected papers. Patented enhancement techniques also are discussed. Enhanced heat transfer has demonstrated significant improvements in performance in many refrigerant applications. However, refrigerant mixtures and refrigerant-oil mixtures have not been studied extensively; no research has been performed with enhanced refrigerant mixtures with oil. Most studies have been of the parametric type; there has been inadequate examination of the fundamental processes governing enhanced refrigerant heat transfer, but some modeling is being done and correlations developed. It is clear that an enhancement technique must be optimized for the refrigerant and operating condition. Fundamental processes governing the heat transfer must be examined if models for enhancement techniques are to be developed; these models could provide the method to optimize a surface. Refrigerant mixtures, with and without oil present, must be studied with enhancement devices; there is too little known to be able to estimate the effects of mixtures (particularly NARMs) with enhanced heat transfer. Other conclusions and recommendations are offered.

  12. IEA Annex 26: Advanced Supermarket Refrigeration/Heat Recovery Systems

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, VAN

    2003-05-19

    With increased concern about the impact of refrigerant leakage on global warming, a number of new supermarket refrigeration system configurations requiring significantly less refrigerant charge are being considered. In order to help promote the development of advanced systems and expand the knowledge base for energy-efficient supermarket technology, the International Energy Agency (IEA) established IEA Annex 26 (Advanced Supermarket Refrigeration/Heat Recovery Systems) under the ''IEA Implementing Agreement on Heat Pumping Technologies''. Annex 26 focuses on demonstrating and documenting the energy saving and environmental benefits of advanced systems design for food refrigeration and space heating and cooling for supermarkets. Advanced in this context means systems that use less energy, require less refrigerant and produce lower refrigerant emissions. Stated another way, the goal is to identify supermarket refrigeration and HVAC technology options that reduce the total equivalent warming impact (TEWI) of supermarkets by reducing both system energy use (increasing efficiency) and reducing total refrigerant charge. The Annex has five participating countries: Canada, Denmark, Sweden, the United Kingdom, and the United States. The working program of the Annex has involved analytical and experimental investigation of several candidate system design approaches to determine their potential to reduce refrigerant usage and energy consumption. Advanced refrigeration system types investigated include the following: distributed compressor systems--small parallel compressor racks are located in close proximity to the food display cases they serve thus significantly shortening the connecting refrigerant line lengths; secondary loop systems--one or more central chillers are used to refrigerate a secondary coolant (e.g. brine, ice slurry, or CO2) that is pumped to the food display cases on the sales floor; self-contained display cases--each food display case

  13. Significance of the non-aceotropic binary refrigerants, when used in heat pumps and refrigeration plants

    Energy Technology Data Exchange (ETDEWEB)

    Jakobs, R. (Technische Univ. Hannover (Germany, F.R.). Abt. Kaeltetechnik); Kruse, H.

    1977-07-01

    For heat pumps, peak energy economy and heat control are important factors for a successful competition with the traditional heating methods. It is demonstrated that non-aceotropic refrigerant mixtures provide considerable advantages for heat pump applications. For this reason, it is proposed to give careful consideration to such mixtures when using heat pump installations. A pilot refrigeration plant designed for technical studies on the plant was mounted at the Technical University of Hannover (FRG). This plant is briefly described.

  14. Two stage sorption type cryogenic refrigerator including heat regeneration system

    Science.gov (United States)

    Jones, Jack A.; Wen, Liang-Chi; Bard, Steven

    1989-01-01

    A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system is disclosed. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

  15. Refrigeration, Heating & Air Conditioning. Post Secondary Curriculum Guide.

    Science.gov (United States)

    Garrison, Joe C.; And Others

    This curriculum guide was designed for use in postsecondary refrigeration, heating and air conditioning education programs in Georgia. Its purpose is to provide for the development of entry level skills in refrigeration, heating, and air conditioning in the areas of air conditioning knowledge, theoretical structure, tool usage, diagnostic ability,…

  16. INFLUENCE OF REFRIGERANT DISTRIBUTION ON HEAT TRANSFER IN EVAPORATORS

    Institute of Scientific and Technical Information of China (English)

    高原; 田怀璋; 曾艳; 袁秀玲

    2003-01-01

    Objective To prevent the maldistribution of two-phase refrigerant in dry expansion evaporators composed of parallel coils, a distributor is needed to supply refrigerant into the coils. Methods A simplified model of dry expansion evaporator was proposed. The flow and heat transfer in distributing pipes and evaporator coils were simulated with a numerical method. Results The heat flow rate decreases while the refrigerant is distributed unequally to evaporator coils. Conclusion In order to maintain the heat flow rate, larger heat transfer area should be arranged to make up the effect of maldistribution. The larger the discrepancy of mass flow rate is, the more heat transfer area is needed.

  17. Advanced Supermarket Refrigeration/ Heat Recovery Systems - Workshop Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Lundqvist, P.

    2001-06-15

    This CD ROM brings together proceedings of the Annex 26 Workshop 'Advanced Supermarket Refrigeration/ Heat Recovery Systems' held in Sweden, 2-3 October 2000. Sessions at the workshop were: Session 1: The supermarket as a system, Session 2: Analysis and modeling, Session 3: Field experiences, Session 4: Energy-efficient equipment. Annex 26 investigates candidate advanced system design approaches to determine their potential to reduce refrigerant usage and energy consumption for both refrigeration and heating/ air conditioning in supermarkets. Advanced supermarket refrigeration system concepts to be considered include, but are not limited to secondary loop systems, distributed compressors systems, and self-contained display cases.

  18. Profile: Department of Refrigeration and Heat Pump Technology

    NARCIS (Netherlands)

    Sluis, S.M. van der

    2000-01-01

    The activities in the fields of refrigeration and heatpumps are concentrated within TNO Environment, Energy and Process Innovation, Apeldoorn, and specifically within the Department of Refrigeration and Heat Pump Technology. The aim of this department is to develop, implement and test: — systems for

  19. Profile: Department of Refrigeration and Heat Pump Technology

    NARCIS (Netherlands)

    Sluis, S.M. van der

    2000-01-01

    The activities in the fields of refrigeration and heatpumps are concentrated within TNO Environment, Energy and Process Innovation, Apeldoorn, and specifically within the Department of Refrigeration and Heat Pump Technology. The aim of this department is to develop, implement and test: — systems for

  20. Cool sound: the future of refrigeration? Thermodynamic and heat transfer issues in thermoacoustic refrigeration

    Science.gov (United States)

    Herman, C.; Travnicek, Z.

    2006-04-01

    During the past two decades the thermoacoustic refrigeration and prime mover cycles gained importance in a variety of refrigeration applications. Acoustic work, sound, can be used to generate temperature differences that allow the transport of heat from a low temperature reservoir to an ambient at higher temperature, thus forming a thermoacoustic refrigeration system. The thermoacoustic energy pumping cycle can also be reversed: temperature difference imposed along the stack plates can lead to sound generation. In this situation the thermoacoustic system operates as a prime mover. Sound generated by means of this thermoacoustic energy conversion process can be utilized to drive different types of refrigeration devices that require oscillatory flow for their operation, such as thermoacoustic refrigerators, pulse tubes and Stirling engines. In order for a thermoacoustic refrigeration or prime mover system as well as a thermoacoustic prime mover driving a non-thermoacoustic refrigeration system to be competitive on the current market, it has to be optimized in order to improve its overall performance. Optimization can involve improving the performance of the entire system as well as its components. The paper addresses some of the thermodynamic and heat transfer issues relevant in improving the performance of the thermoacoustic system, such as optimization for maximum COP, maximum cooling load and the role of the heat exchangers. Results obtained using the two optimization criteria are contrasted in the paper to illustrate the complexity of the optimization process.

  1. The optimization of Stirling refrigerator and Stirling heat engine

    Science.gov (United States)

    Zhu, Xin-Mei

    2007-03-01

    The optimization of an irreversible Stirling refrigerator or a Stirling heat engine is an important research subject for a long time. Taking into account of the influence of mixed thermal resistance and regeneration loss in the performance study, we have derived the optimal relation of both of them. For Stirling refrigerator, we have deduced the optimal relation between the thermal resistance coefficient and the efficiency. To the Stirling heat engine, we have deduced the optimal relation between the power output and the efficiency. The conclusions obtained mirror the observed performance of the Stirling refrigerator or the Stirling heat engine quite well. Thus, the results may provide a new theoretical guidance to the optimal design and the selection of optimal operating condition of the Stirling refrigerator or the Stirling heat engine.

  2. Advanced Supermarket Refrigeration/Heat Recovery Systems. Country Report, Denmark

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard; Christensen, K. G.

    Annex 26 is the first international project under the IEA Heat Pump Programme that links refrigeration and heat pump technology. Recovering heat from advanced supermarket refrigeration systems for space and water heating seems obvious and is beneficial for owners and operators. Because the great...... conclusions as far energy conservation and TEWI reduction is concerned. The conclusion justify that advanced supermarket systems with heat recovery should receive great attention and support. And there is still further research needed in several areas. The Annex also included a thorough system analyses...

  3. Advanced Supermarket Refrigeration / Heat Recovery Systems. Annex 26

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-06-01

    This CD-ROM contains the proceedings (16 papers) of a workshop (held in Stockholm, Sweden, 2-3 October 2000) on Advanced Supermarket Refrigeration/ Heat Recovery Systems. Sessions at the workshop discussed: The supermarket as a system, Analysis and modelling, Field experiences and Energy-efficient equipment. The 16 papers presented at the workshop provide a useful information source for all involved in supermarket refrigeration.

  4. Dynamic Heat Transfer Model of Refrigerated Foodstuff

    DEFF Research Database (Denmark)

    Cai, Junping; Risum, Jørgen; Thybo, Claus

    2006-01-01

    Commercial refrigerating systems need to be defrosted regularly to maintain a satisfactory performance. When defrosting the evaporator coil, the air temperature inside the display cabinet will increase, and float outside the normal temperature range for a period of time, the question is what...... as what is the optimal defrost scheme from food quality point of view are answered. This will serve as a prerequisite of designing of optimal control scheme for the commercial refrigeration system, aiming at optimizing a weighed cost function of both food quality and overall energy consumption of system....

  5. Four K refrigerators with a new compact heat exchanger

    Science.gov (United States)

    Longsworth, R. C.; Steyert, W. A.

    1985-01-01

    Two refrigerators have been developed which have nominal cpacities of 0.25M and 0.5W at 4.2K. These use standard two stage Displex sup R expanders and compressors combined with a new compact heat exchanger which is concentric with the expander cylinder. These refrigerators can be used to cool superconducting electronic devices by direct attachment to the 4K heat station, or they can be plugged into the neck of a liquid helium superconducting magnet cryostat where they can cool the radiation shields and reliquefy helium.

  6. Heat powered refrigeration compressor. Semi-annual technical report

    Energy Technology Data Exchange (ETDEWEB)

    Goad, R.R.

    1981-01-01

    The objective of this program is to develop and improve the design of previously started prototypes of the Heat Powered Refrigeration Compressor. To build this prototype and ready it for testing by the University of Evansville is another goal. This prototype will be of similar capacity as the compressor that will eventually be commercially produced. This unit can operate on almost any moderate temperature water heat source. This heat source could include such applications as industrial waste heat, solar, wood burning stove, resistance electrical heat produced by a windmill, or even perhaps heat put out by the condenser of another refrigeration system. Work performed in the past four months has consisted of: engineering of HX-1; comparisons of specifications from different companies to ensure state of the art applications of parts for project; coordinating project requirements with machine shop; designing condenser; and partial assembly of HX-1.

  7. Generalized Performance Characteristics of Refrigeration and Heat Pump Systems

    Directory of Open Access Journals (Sweden)

    Mahmoud Huleihil

    2010-01-01

    Full Text Available A finite-time generic model to describe the behavior of real refrigeration systems is discussed. The model accounts for finite heat transfer rates, heat leaks, and friction as different sources of dissipation. The performance characteristics are cast in terms of cooling rate (r versus coefficient of performance (w. For comparison purposes, various types of refrigeration/heat pump systems are considered: the thermoelectric refrigerator, the reverse Brayton cycle, and the reverse Rankine cycle. Although the dissipation mechanisms are different (e.g., heat leak and Joule heating in the thermoelectric refrigerator, isentropic losses in the reverse Brayton cycle, and limits arising from the equation of state in the reverse Rankine cycle, the r−w characteristic curves have a general loop shape. There are four limiting types of operation: open circuit in which both r and w vanish in the limit of slow operation; short circuit in which again r and w vanish but in the limit of fast operation; maximum r; maximum w. The behavior of the considered systems is explained by means of the proposed model. The derived formulae could be used for a quick estimation of w and the temperatures of the working fluid at the hot and cold sides.

  8. TESTING OF REFRIGERANT MIXTURES IN RESIDENTIAL HEAT PUMPS

    Science.gov (United States)

    The report gives results of an investigation of four possibilities for replacing Hydrochlorofluorocarbon-22 (HCFC-22) with the non-ozone-depleting new refrigerants R-407D and R-407C in residential heat pumps. The first and simplest scenario was a retrofit with no hardware modific...

  9. An Analysis of the Air Conditioning, Refrigerating and Heating Occupation.

    Science.gov (United States)

    Frass, Melvin R.; Krause, Marvin

    The general purpose of the occupational analysis is to provide workable, basic information dealing with the many and varied duties performed in the air conditioning, refrigerating, and heating occupation. The document opens with a brief introduction followed by a job description. The bulk of the document is presented in table form. Six duties are…

  10. Air Conditioning, Heating, and Refrigeration. Competency-Based Curriculum Manual.

    Science.gov (United States)

    Gourley, Frank A., Jr.

    This manual was developed to serve as an aid to administrators and instructors involved with postsecondary air conditioning, heating, and refrigeration programs. The first of six chapters contains general information on program implementation, the curriculum design, facilities and equipment requirements, and textbooks and references. Chapter 2…

  11. State Skill Standards: Heating, Ventilation, Air Conditioning, and Refrigeration

    Science.gov (United States)

    Ball, Larry; Soukup, Dennis

    2006-01-01

    The Department of Education has undertaken an ambitious effort to develop statewide career and technical education skill standards. The standards in this document are for Heating, Ventilation, Air Conditioning and Refrigeration (HVAC&R) programs and are designed to clearly state what the student should know and be able to do upon completion of…

  12. Heating, Air-Conditioning, and Refrigeration Technician. National Skill Standards.

    Science.gov (United States)

    Vocational Technical Education Consortium of States, Decatur, GA.

    This guide contains information on the knowledge and skills identified by industry as essential to the job performance of heating, air-conditioning, and refrigeration technicians. It is intended to assist training providers in public and private institutions, as well as in industry, to develop and implement training that will provide workers with…

  13. Characteristics of a Refrigeration Cycle Using a Zeotropic Refrigerant Mixture with a Temperature Glide Shift Heat Exchanger

    Science.gov (United States)

    Endoh, Kazuhiro; Matsushima, Hiroaki; Nonaka, Masayuki

    HFC zeotropic refrigerant mixture R-407C is one of the promising alternatives for HCFC-22. We have found that the coefficient of performance (COP) of the refrigeration cycle using R-407C is improved by installing a temperature glide shift heat exchanger (TGSX) which takes advantage of zeotropic characteristics to an air-conditioner. We obtained the characteristics of a refrigeration cycle of experimental apparatus with comparison to those of a fundamental refrigeration cycle based on the refrigerant thermodynamic properties. We concluded that the COP improvement ratio of experimental apparatus with the TGSX to that without the TGSX is greater than that ratio which is calculated from the fundamental refrigeration cycle. This proved to be caused by the pressure loss of low pressure side which is not taken into account in the fundamental refrigeration cycle.

  14. 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.

  15. Heat Transfer Performance of Absorber of Absorption Refrigerating Machine

    Science.gov (United States)

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

    Experimental studies on heat transfer performance of absorber for lithium bromide-water absorption refrigerating machine are presented in this paper. Experimental apparatus for 35 kW evaporator and absorber, and outer grooved tubes are used. As a result, over-al1 coefficient of heat transmission of absorber has a maximum value, in the case of heat transfer area ratio of absorber to evaporator, is about 0.8. Heat transfer rate of absorber is increased by 60% by using the outer grooved tube compared with the plane surfaced tube.

  16. Dynamic Heat Transfer Model of Refrigerated Foodstuff

    DEFF Research Database (Denmark)

    Cai, Junping; Risum, Jørgen; Thybo, Claus

    2006-01-01

    their temperature relation. This paper discusses the dynamic heat transfer model of foodstuff inside the display cabinet, one-dimensional dynamic model is developed, and the Explicit Finite Difference Method is applied, to handle the unsteady heat transfer problem with phase change, as well as time varying boundary...

  17. Recent evolutions of refrigerating machineries and heat pumps; Evolutions recentes des machines a froid et thermopompes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This book of proceedings reports on 10 papers (or series of transparencies) concerning some recent developments about refrigerating machineries and heat pumps as used in space heating, air-conditioning and industrial refrigeration. Various aspects are developed: thermodynamic cycles, thermal performances, dimensioning, modeling, refrigerants substitution, design of flanged exchangers, compressors etc.. (J.S.)

  18. Experimental study on heat transfer performance of pulsating heat pipe with refrigerants

    Science.gov (United States)

    Wang, Xingyu; Jia, Li

    2016-10-01

    The effects of different refrigerants on heat transfer performance of pulsating heat pipe (PHP) are investigated experimentally. The working temperature of pulsating heat pipe is kept in the range of 20°C-50°C. The startup time of the pulsating heat pipe with refrigerants can be shorter than 4 min, when heating power is in the range of 10W?100W. The startup time decreases with heating power. Thermal resistances of PHP with filling ratio 20.55% were obviously larger than those with other filling ratios. Thermal resistance of the PHP with R134a is much smaller than that with R404A and R600a. It indicates that the heat transfer ability of R134a is better. In addition, a correlation to predict thermal resistance of PHP with refrigerants was suggested.

  19. Possibility of using adsorption refrigeration unit in district heating network

    Science.gov (United States)

    Grzebielec, Andrzej; Rusowicz, Artur; Jaworski, Maciej; Laskowski, Rafał

    2015-09-01

    Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  20. Intermittent duty solar refrigerator assisted by heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hindi, R.R.; Khalifa, A.M.A.; Akyurt, M.

    1988-01-01

    The design of a solar operated intermittent-duty aqua-ammonia type of absorption refrigerator is described. The generator is heated by an integral acetone heat pipe, the evaporator of which is in the form of a low-thermal-mass flat plate collector. The condenser is air cooled. The absorber is likewise cooled via a second R22 heat-pipe system by convection/radiation panels. Initial test results for the collector-generator loop are reported for a single-glazed collector. A discussion of overall performance is presented.

  1. Investigation of two-phase heat transfer coefficients of argon-freon cryogenic mixed refrigerants

    Science.gov (United States)

    Baek, Seungwhan; Lee, Cheonkyu; Jeong, Sangkwon

    2014-11-01

    Mixed refrigerant Joule Thomson refrigerators are widely used in various kinds of cryogenic systems these days. Although heat transfer coefficient estimation for a multi-phase and multi-component fluid in the cryogenic temperature range is necessarily required in the heat exchanger design of mixed refrigerant Joule Thomson refrigerators, it has been rarely discussed so far. In this paper, condensation and evaporation heat transfer coefficients of argon-freon mixed refrigerant are measured in a microchannel heat exchanger. A Printed Circuit Heat Exchanger (PCHE) with 340 μm hydraulic diameter has been developed as a compact microchannel heat exchanger and utilized in the experiment. Several two-phase heat transfer coefficient correlations are examined to discuss the experimental measurement results. The result of this paper shows that cryogenic two-phase mixed refrigerant heat transfer coefficients can be estimated by conventional two-phase heat transfer coefficient correlations.

  2. Symposium on advances in refrigeration and heat pump technology. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Elmegaard, B.; Brix, W.; Ryhl Kaern, M. (and others)

    2012-06-15

    Technical University of Denmark - Department of Mechanical Engineering, Danish Technological Institute, and the Danish Energy Association in collaboration hosted a two-day symposium covering advances in refrigeration and heat pump technology on the 15th and 16th of May 2012. These proceedings are the formal documentation of the lectures that were given over the two days on several topics of significant relevance for the future development of technology for cooling and heating application. The focus was on both the industrial development of solutions for domestic, commercial and industrial applications in the near future as well as the scientific and engineering research in the more distant years to come. Applications of compression technology, phase changing materials and magnetic refrigeration were presented as well as novel results for selection of working fluids and design of cycles, development of components and cycles. (LN)

  3. Research and application of CO2 refrigeration and heat pump cycle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The environmental problem caused by refrigerant has become the focus all over the world.As the most typical natural refrigerant,CO2,of course,becomes the research focus.This paper introduces the development and application status of CO2 refrigeration and heat pump technology.The researches on CO2 refrigeration and heat pump,carried out by Thermal Energy Research Institute,Tianjin University,also are presented in this paper.

  4. Research and application of CO2 refrigeration and heat pump cycle

    Institute of Scientific and Technical Information of China (English)

    TIAN Hua; YANG Zhao; LI MinXia; MA YiTai

    2009-01-01

    The environmental problem caused by refrigerant has become the focus all over the world. As the most typical natural refrigerant, CO2, of course, becomes the research focus. This paper introduces the develop-ment and application status of CO2 refrigeration and heat pump technology. The researches on CO2 refrig-eration and heat pump, carried out by Thermal Energy Research Institute, Tianjin University, also are pre-sented in this paper.

  5. Possibility of using adsorption refrigeration unit in district heating network

    Directory of Open Access Journals (Sweden)

    Grzebielec Andrzej

    2015-09-01

    Full Text Available Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.

  6. A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus

    Energy Technology Data Exchange (ETDEWEB)

    Raustad, Richard A. [Florida Solar Energy Center

    2013-01-01

    This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

  7. Refrigerant Control Strategies for Residential Air-Conditioning and Heat-Pump System

    Institute of Scientific and Technical Information of China (English)

    SU Shun-yu; ZHANG Chun-zhi; CHEN Jian

    2009-01-01

    This paper simulated the optimal refrigerant charge inventory of a refrigeration system in air-con-ditioning operation and heat-pump operation respectively,and studied the refrigerant control strategies in this system.The void fraction in two-phase fluid region was calculated by Harms model.And based on distributed parameter model and Harms model,the refrigerant charge inventory in condenser and evaporator were calculated and analyzed in air-conditioning conditions and heat-pump conditions,respectively.The calculating results of dif-ferent refrigerant mass between refrigeration and heating conditions indicate that the optimal refrigerant charge inventory in heat-pump conditions is lower than that in air-eonditioning conditions.To avoid the decrease of COP due to the surplus refrigerant in heating conditions,we introduced the liquid reservoir control method and associate capillary control method.Both of them could increase the heating capacity of the air-source heat pump-The difference of optimal refrigerant charge inventory in air-conditioning and heat-pump system can be controlled by the liquid reservoir or the associate capillary.

  8. 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

    International work on refrigerants is aiming at phasing out HFC. The solution might be natural refrigerants. Within 15-20 years, when present heat pumps for district heating in Sweden are likely not in service any longer, it might still be good economy to install new heat pumps since only the machines need to be replaced. This report describes the possibilities to use natural refrigerants. A first screening resulted in further study on some hydrocarbons, ammonia and carbon dioxide. Water was considered to require too large volumes. In present plants it is practically not possible to use any natural refrigerants, partly because the compressors are not adapted. In new plants the situation is different. Today it is technically possible to install new heat pumps in the studied size, 15 MW{sub th}, using ammonia or hydrocarbons as refrigerant. But likely it is very difficult to get permits from authorities since the refrigerants are toxic or highly flammable. There is substantial international research on using carbon dioxide, and this refrigerant is also used in some applications. Carbon dioxide is used at high pressure and in a trans-critical process. Surprisingly, it turned out that one compressor manufacturer considers it possible to supply a heat pump for district heating within 5 years. This development has taken place in Russia, mainly for domestic use. Thus, within 15 to 20 years there will probably exist a technique where carbon dioxide is used. However, more development is needed. Additionally, low district heating return temperatures are also needed to get an acceptable COP. The investment cost for a heat pump installation is considered to be approx. 30 % higher when using ammonia or propane compared to using R134a. When using carbon dioxide there is in the longer run potential to get lower cost than for R134a. The COPs are almost identical if the systems are properly designed. In the carbon dioxide case the COP is somewhat lower, but has a potential for

  9. System for vaporizing carbon dioxide utilizing the heat by-product of the refrigeration system as a heat source

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, H.L.

    1980-12-23

    The present invention is directed to a carbonation and refrigeration system wherein the heat of the refrigerant output side of the refrigeration compressor is utilized to vaporize liquid carbon dioxide into CO/sub 2/ gas which is introduced into a liquid product. The carbonation and refrigeration system successfully utilizes the heat of the refrigerant to vaporize the CO/sub 2/ liquid regardless of the cooling demand of the system caused by seasonal temperature variations. For example during the winter months when the cooling demand is as low as 10% of the cooling demand in the summer, the carbonation and refrigeration system operates effectively to vaporize the CO/sub 2/ liquid by means of a heat exchanger and a desuperheater which are connected in communication with the superheated vapor emerging from the output side of a refrigeration compressor. In addition, the carbonation and refrigeration system of the present invention cools more efficiently by extracting some of the heat from the condensed refrigerant entering the receiver of the refrigeration system. In this manner, the refrigeration compressor can operate more efficiently.

  10. Two-statge sorption type cryogenic refrigerator including heat regeneration system

    Science.gov (United States)

    Jones, Jack A. (Inventor); Wen, Liang-Chi (Inventor); Bard, Steven (Inventor)

    1989-01-01

    A lower stage chemisorption refrigeration system physically and functionally coupled to an upper stage physical adsorption refrigeration system. Waste heat generated by the lower stage cycle is regenerated to fuel the upper stage cycle thereby greatly improving the energy efficiency of a two-stage sorption refrigerator. The two stages are joined by disposing a first pressurization chamber providing a high pressure flow of a first refrigerant for the lower stage refrigeration cycle within a second pressurization chamber providing a high pressure flow of a second refrigerant for the upper stage refrigeration cycle. The first pressurization chamber is separated from the second pressurization chamber by a gas-gap thermal switch which at times is filled with a thermoconductive fluid to allow conduction of heat from the first pressurization chamber to the second pressurization chamber.

  11. Refrigeration, heating and air conditioning pocket book 2012; Kaelte, Waerme, Klima. Taschenbuch 2012

    Energy Technology Data Exchange (ETDEWEB)

    Schaedlich, Sylvia (ed.)

    2011-07-01

    The refrigeration, heating and air conditioning pocket book 2012 contains a calendar of important events and technical fairs. A publication of this type requires constant updating, and this is what was done in this pocket book. The technical documentation contains the following aspects: General working basis; special working basis of refrigeration; coolants; refrigeration; air-conditioning technology; heating technology; measurement and control technology; general information.

  12. Optimal configuration for a finite low-temperature source refrigerator cycle with heat transfer law

    Directory of Open Access Journals (Sweden)

    Jun Li, Lingen Chen, Yanlin Ge, Fengrui Sun

    2016-01-01

    Full Text Available The optimal configuration of a refrigeration cycle operating between a finite low-temperature source and an infinite high-temperature sink are derived by using finite time thermodynamics based on a complex heat transfer law, including Newtonian heat transfer law, linear phenomenological heat transfer law, radiative heat transfer law, Dulong-Petit heat transfer law, generalized convective heat transfer law and generalized radiative heat transfer law. In the refrigeration cycle model the only irreversibility of finite rate heat transfer is considered. The optimal relation between cooling load and coefficient of performance (COP of the refrigeration cycle is also derived by using an equivalent temperature of low-temperature source. The obtained results include those with various heat transfer laws and infinite low-temperature source, and can provide some theoretical guidelines for the designs of practical refrigerators.

  13. Pressure drop characteristics of cryogenic mixed refrigerant at macro and micro channel heat exchangers

    Science.gov (United States)

    Baek, Seungwhan; Jeong, Sangkwon; Hwang, Gyuwan

    2012-12-01

    Mixed Refrigerant-Joule Thomson (MR-JT) refrigerators are widely used in various kinds of cryogenic systems these days. The temperature glide effect is one of the major features of using mixed refrigerants since a recuperative heat exchanger in a MR-JT refrigerator is utilized for mostly two-phase flow. Although a pressure drop estimation for a multi-phase and multi-component fluid in the cryogenic temperature range is necessarily required in MR-JT refrigerator heat exchanger designs, it has been rarely discussed so far. In this paper, macro heat exchangers and micro heat exchangers are compared in order to investigate the pressure drop characteristics in the experimental MR-JT refrigerator operation. The tube in tube heat exchanger (TTHE) is a well-known macro-channel heat exchanger in MR-JT refrigeration. Printed Circuit Heat Exchangers (PCHEs) have been developed as a compact heat exchanger with micro size channels. Several two-phase pressure drop correlations are examined to discuss the experimental pressure measurement results. The result of this paper shows that cryogenic mixed refrigerant pressure drop can be estimated with conventional two-phase pressure drop correlations if an appropriate flow pattern is identified.

  14. Criterion-Referenced Test (CRT) Items for Air Conditioning, Heating and Refrigeration.

    Science.gov (United States)

    Davis, Diane, Ed.

    These criterion-referenced test (CRT) items for air conditioning, heating, and refrigeration are keyed to the Missouri Air Conditioning, Heating, and Refrigeration Competency Profile. The items are designed to work with both the Vocational Instructional Management System and Vocational Administrative Management System. For word processing and…

  15. SIMULATION OF NON-AZEOTROPIC REFRIGERANT MIXTURES FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER WITH COUNTERCURRENT HEAT EXCHANGES

    Science.gov (United States)

    The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. This RF is housed in a stan...

  16. Boiling heat transfer of refrigerant R-21 in upward flow in plate-fin heat exchanger

    Science.gov (United States)

    Kuznetsov, V. V.; Shamirzaev, A. S.

    2015-11-01

    The article presents the results of experimental investigation of boiling heat transfer of refrigerant R-21 in upward flow in a vertical plate-fin heat exchanger with transverse size of the channels that is smaller than the capillary constant. The heat transfer coefficients obtained in ranges of small mass velocities and low heat fluxes, which are typical of the industry, have been poorly studied yet. The characteristic patterns of the upward liquid-vapor flow in the heat exchanger channels and the regions of their existence are detected. The obtained data show a weak dependence of heat transfer coefficient on equilibrium vapor quality, mass flow rate, and heat flux density and do not correspond to calculations by the known heat transfer models. A possible reason for this behavior is a decisive influence of evaporation of thin liquid films on the heat transfer at low heat flux.

  17. Quantum Thermodynamics in Strong Coupling: Heat Transport and Refrigeration

    Directory of Open Access Journals (Sweden)

    Gil Katz

    2016-05-01

    Full Text Available The performance characteristics of a heat rectifier and a heat pump are studied in a non-Markovian framework. The device is constructed from a molecule connected to a hot and cold reservoir. The heat baths are modelled using the stochastic surrogate Hamiltonian method. The molecule is modelled by an asymmetric double-well potential. Each well is semi-locally connected to a heat bath composed of spins. The dynamics are driven by a combined system–bath Hamiltonian. The temperature of the baths is regulated by a secondary spin bath composed of identical spins in thermal equilibrium. A random swap operation exchange spins between the primary and secondary baths. The combined system is studied in various system–bath coupling strengths. In all cases, the average heat current always flows from the hot towards the cold bath in accordance with the second law of thermodynamics. The asymmetry of the double well generates a rectifying effect, meaning that when the left and right baths are exchanged the heat current follows the hot-to-cold direction. The heat current is larger when the high frequency is coupled to the hot bath. Adding an external driving field can reverse the transport direction. Such a refrigeration effect is modelled by a periodic driving field in resonance with the frequency difference of the two potential wells. A minimal driving amplitude is required to overcome the heat leak effect. In the strong driving regime the cooling power is non-monotonic with the system–bath coupling.

  18. Simulation methods of rocket fuel refrigerating with liquid nitrogen and intermediate heat carrier

    Directory of Open Access Journals (Sweden)

    O. E. Denisov

    2014-01-01

    Full Text Available Temperature preparation of liquid propellant components (LPC before fueling the tanks of rocket and space technology is the one of the operations performed by ground technological complexes on cosmodromes. Refrigeration of high-boiling LPC is needed to increase its density and to create cold reserve for compensation of heat flows existing during fueling and prelaunch operations of space rockets.The method and results of simulation of LPC refrigeration in the recuperative heat exchangers with heat carrier which is refrigerated by-turn with liquid nitrogen sparging. The refrigerating system consists of two tanks (for the chilled coolant and LPC, LPC and heat carrier circulation loops with heat exchanger and system of heat carrier refrigeration in its tank with bubbler. Application of intermediate heat carrier between LPC and liquid nitrogen allows to avoid LPC crystallization on cold surfaces of the heat exchanger.Simulation of such systems performance is necessary to determine its basic design and functional parameters ensuring effective refrigerating of liquid propellant components, time and the amount of liquid nitrogen spent on refrigeration operation. Creating a simulator is quite complicated because of the need to take into consideration many different heat exchange processes occurring in the system. Also, to determine the influence of various parameters on occurring processes it is necessary to take into consideration the dependence of all heat exchange parameters on each other: heat emission coefficients, heat transfer coefficients, heat flow amounts, etc.The paper offers an overview of 10 references to foreign and Russian publications on separate issues and processes occurring in liquids refrigerating, including LPC refrigeration with liquid nitrogen. Concluded the need to define the LPC refrigerating conditions to minimize cost of liquid nitrogen. The experimental data presented in these publications is conformed with the application of

  19. Experimental performance evaluation of heat pump by using CO2 as a refrigerant

    Science.gov (United States)

    Venkatesh, V. K.; Basavaraju, M. G.; Sreenivas Rao, K. V.

    2016-09-01

    In this experiment the refrigerant used is CO2 which is naturally available, eco friendly, economical, non toxic, non flammable and non corrosive. Its Ozone Depletion Potential (ODP) is zero and minimum Global Warming Potential (GWP). The performance evaluation of prototype vapor compression heat pump model was performed and evaluated the different parameters like COP (Co-efficient of performance), LMTD (Logarithmic mean temperature difference) and outlet water temperature of condenser. The experiment is carried out for two different condensers by varying mass flow rate and pressure. The water in the shell side was heated by absorbing heat from refrigerants in the tube side of condensers by counter flow heat exchanging method. The experimental result indicates fairly good COP with the use of CO2 refrigerant. These advantages of CO2 as a refrigerant favors the replacement for globally used refrigerant with CO2.

  20. Advanced Supermarket Refrigeration/Heat Recovery Systems Vol 1 - Executive Summary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-15

    Annex 26 is the first international project under the IEA Heat Pump Programme that links refrigeration and heat pump technology. Recovering heat from advanced supermarket refrigeration systems for space and water heating purposes seems obvious and is beneficial for owners and operators. Because there are world-wide a great number of supermarkets that offer frozen and chilled food under further growth of this sector may be expected, the amount of energy used for refrigeration is enormous and will likely increase substantially in the near future. This volume of the IEA Annex 26 final report contains a detailed summary of the Annex activities including principal conclusions from each participant.

  1. Influence of the Water-Cooled Heat Exchanger on the Performance of a Pulse Tube Refrigerator

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2017-02-01

    Full Text Available The water-cooled heat exchanger is one of the key components in a pulse tube refrigerator. Its heat exchange effectiveness directly influences the cooling performance of the refrigerator. However, effective heat exchange does not always result in a good performance, because excessively reinforced heat exchange can lead to additional flow loss. In this paper, seven different water-cooled heat exchangers were designed to explore the best configuration for a large-capacity pulse tube refrigerator. Results indicated that the heat exchanger invented by Hu always offered a better performance than that of finned and traditional shell-tube types. For a refrigerator with a working frequency of 50 Hz, the best hydraulic diameter is less than 1 mm.

  2. Thermodynamic optimization of heat-driven refrigerators in the transient regime

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, J.V.C.; Parise, J.A.R.; Ledezma, G.A.; Bianchi, M.V.A.

    2000-02-01

    The present work introduces a transient endoreversible model of a heat-driven refrigeration plant, which is driven by a fuel-burning heater. The model consists of a combustion chamber with negligible heat loss to the ambient, a refrigerator with three finite-size heat exchangers, namely, the evaporator between the refrigeration load and refrigerant, the condenser between the refrigerant and the ambient, and the generator between the combustion chamber and the refrigerant, and finally the refrigerated space. The total thermal conductance of the three heat exchangers is fixed. A thermodynamic optimization of the absorption cycle is then performed, reporting the operating conditions for minimum time to reach a prescribed cold-space temperature, thus maximum refrigeration rate, specifically, the optimal mass fuel flow rate and the optimal way of allocating the thermal conductance inventory. Half of the total supply of thermal conductance has to be divided equally between the generator and evaporator and the other half allocated to the condenser, for optimal operation. A narrow range of fuel flow rates lead to the minimum time to achieve a prescribed cold-space temperature, thus stressing the importance of the transient analysis. Appropriate dimensionless groups were identified and the generalized results are reported in dimensionless charts.

  3. Energy and exergy analysis of heat pump using R744/R32 refrigerant mixture

    Directory of Open Access Journals (Sweden)

    Wang Fang

    2014-01-01

    Full Text Available An energy and exergy analysis of heat pump with blends of refrigerant mixture R744/R32 was carried out. The coefficient of performance and exergy efficiency of the system were studied with different mass fraction of R744 in the blends and different heat source temperatures. The volumetric heat capacity, condensing pressure, discharge temperature, and compression ratio were also investigated. The results indicate that at a certain concentration (15/85 by mass, the blends achieve better performance, and are superior to those of R22, the results also show that the new refrigerant mixture is an attractive option for promising alternative refrigerant.

  4. COP improvement of refrigerator/freezers, air-conditioners, and heat pumps using nonazeotropic refrigerant mixtures

    Science.gov (United States)

    Westra, Douglas G.

    1993-01-01

    With the February, 1992 announcement by President Bush to move the deadline for outlawing CFC (chloro-fluoro-carbon) refrigerants from the year 2000 to the year 1996, the refrigeration and air-conditioning industries have been accelerating their efforts to find alternative refrigerants. Many of the alternative refrigerants being evaluated require synthetic lubricants, are less efficient, and have toxicity problems. One option to developing new, alternative refrigerants is to combine existing non-CFC refrigerants to form a nonazeotropic mixture, with the concentration optimized for the given application so that system COP (Coefficient Of Performance) may be maintained or even improved. This paper will discuss the dilemma that industry is facing regarding CFC phase-out and the problems associated with CFC alternatives presently under development. A definition of nonazeotropic mixtures will be provided, and the characteristics and COP benefits of nonazeotropic refrigerant mixtures will be explained using thermodynamic principles. Limitations and disadvantages of nonazeotropic mixtures will be discussed, and example systems using such mixtures will be reviewed.

  5. Performance evaluation of a vapor compression heat pump cycle using binary zeotropic refrigerant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Shigeru; Yara, Tomoyasu

    1999-07-01

    The HCFC refrigerants such as R22 have been used widely as working fluids in refrigeration and air-conditioning systems until now. These refrigerants, however, should be phased out early in the next century to prevent the depletion of the ozone layer. In this situation, binary and/or ternary mixtures composed of HFC and/or natural refrigerants have attracted a great deal of attention due to the following possibilities: (1) to improve the coefficient of performance, COP, by utilizing the temperature glide during phase change processes; (2) to keep the system in more suitable condition for given temperature levels of heat source and heat sink by selecting the combination and composition of refrigerants, etc. From this point of view, in the present study, the performance prediction of a vapor compression heat pump cycle using binary zeotropic refrigerant mixtures is carried out to clarify the effects of the combination of refrigerants, the composition of refrigerants and the size of heat exchangers on COP. In the prediction calculation, a vapor compression heat pump cycle, which consists of a compressor, a vertical plate-fin condenser, an expansion valve, a liquid-vapor separator and a vertical plate-fin evaporator is treated, and the following assumptions are employed: (1) the compression process is isentropic, (2) the expansion process is isenthalpic, (3) the refrigerant is a saturated liquid at the condenser outlet and a superheated vapor at the evaporator outlet, (4) the pressure drop in the condenser is negligible, while that in the evaporator is considered, (5) the local heat transfer characteristics in heat exchangers are considered. The prediction calculation is done for the binary zeotropic refrigerant mixtures of HFC134a/HCFC123 on condition that the heat source water temperature at the condenser outlet, the heat sink water temperature at the evaporator inlet, the water temperature change through condenser and evaporator, the heat load of condenser, the

  6. Mini-channel evaporator/heat pipe assembly for a chip cooling vapor compression refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Guilherme B.; Barbosa, Jader R. Jr.; Prata, Alvaro T. [Polo - Research Laboratories for Emerging Technologies in Cooling and Thermophysics, Department of Mechanical Engineering, Campus Universitario, Trindade, Federal University of Santa Catarina, Florianopolis, SC 88040900 (Brazil)

    2010-11-15

    We investigate a novel evaporator design for a small-scale refrigeration system whose function is to assist the existing heat pipe technology currently used in chip cooling of portable computers. A heat transfer model for the evaporator/heat pipe assembly was devised specifically for sizing the evaporator in order to keep the chip surface temperature below a certain value. A prototype was tested with R-600a at saturation temperatures of 45 and 55 C, mass flow rates between 0.5 and 1.5 kg h{sup -1} and heat transfer rates between 30 and 60 W. The experimental results demonstrated that the average refrigerant-side heat transfer coefficient is more sensitive to a change in the refrigerant mass flux than to changes in the saturation temperature and heat transfer rate. The agreement between the calculated heat transfer coefficient and the data was within {+-}10% for the conditions evaluated. (author)

  7. From Consumption to Prosumption - Operational Cost Optimization for Refrigeration System With Heat Waste Recovery

    DEFF Research Database (Denmark)

    Minko, Tomasz; Garcia, Jesus Lago; Bendtsen, Jan Dimon;

    2017-01-01

    Implementation of liquid cooling transforms a refrigeration system into a combined cooling and heating system. Reclaimed heat can be used for building heating purposes or can be sold. Carbon dioxide based refrigeration systems are considered to have a particularly high potential for becoming ecient...... heat energy producers. In this paper a CO2 system that operates in the subcritical region is examined. Modelling approach is presented, and used for operation optimisation by way of non-linear model predictive control techniques. Assuming that the heat is sold when using both objective functions...

  8. Operation and maintenance of Fermilab`s satellite refrigerator expansion engines

    Energy Technology Data Exchange (ETDEWEB)

    Soyars, W.M.

    1996-09-01

    Fermilab`s superconducting Tevatron accelerator is cooled to liquid helium temperatures by 24 satellite refrigerators, each of which uses for normal operations a reciprocating `wet` expansion engine. These expanders are basically Process System (formerly Koch) Model 1400 expanders installed in standalone cryostats designed by Fermilab. This paper will summarize recent experience with operations and maintenance of these expansion engines. Some of the statistics presented will include total engine hours, mean time between major and minor maintenance, and frequent causes of major maintenance.

  9. AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Muhammad Asmail Eleiwi

    2013-05-01

    Full Text Available Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle.  Two cases of  vapor compression refrigeration cycle were takenin this paper:  the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin  the second case the vapor compressionrefrigeration cycle with heat exchanger ; in these two cases, the temperatureat each point of  a vapor compressionrefrigeration cycle, the low and the high pressure ,the indoor temperature andthe outdoor temperature were measured at each time at compressor speed 1450 rpmand 2900 rpm for each blower speed 1, blower speed 2 and blower speed 3.Therefrigerant fluid was used in the vapor compression refrigeration cycle withoutIHE and with IHE is R134a..

  10. Regeneration tests of a room temperature magnetic refrigerator and heat pump

    CERN Document Server

    Brown, G V

    2014-01-01

    A magnetic heat pump apparatus consisting of a solid magnetic refrigerant, gadolinium, and a liquid regenerator column of ethanol and water has been tested. Utilizing a 7T field, it produced a maximum temperature span of 80 K, and in separate tests, a lowest temperature of 241 K and a highest temperature of 328 K. Thermocouples, placed at intervals along the regenerator tube, permitted measurement of the temperature distribution in the regenerator fluid. No attempt was made to extract refrigeration from the device, but analysis of the temperature distributions shows that 34 watts of refrigeration was produced.

  11. Microchannel heat exchanger for two-phase Mixed Refrigerant Joule Thomson process

    Science.gov (United States)

    Baek, Seungwhan; Lee, Jisung; Lee, Cheonkyu; Jeong, Sangkwon

    2014-01-01

    Mixed Refrigerant Joule Thomson (MR-JT) refrigerators are widely used in various kinds of cryogenic systems these days. Printed Circuit Heat Exchanger (PCHE) is one of the promising cryogenic compact recuperators for MR-JT refrigerators due to its compactness, high NTU and robustness. However, PCHE composed with microchannel bundles can cause flow mal-distribution, and it can cause the degradation of thermal performance of the system. To mitigate the flow mal-distribution problem, the cross link (or intra-layer bypass) can be adapted to parallel microchannels. Two heat exchangers are fabricated in this study; one has straight channels, and the other one has intra-layer bypass structure between channels to enhance the flow distribution. The MR-JT refrigerators are operated with these two heat exchanger and the no-load temperatures are compared. The lower no load temperature achieved with the intra-layer bypass structured heat exchanger. The results indicate that the flow mal-distribution in the microchannel heat exchanger can be mitigated with intra-layer bypass structure, and relaxation of flow mal-distribution in the heat exchanger guarantee the MR-JT refrigerator's performance.

  12. Prediction of condensation heat transfer of low GWP refrigerants inside smooth horizontal tube

    Science.gov (United States)

    Hossain, Md. Anowar; Afroz, Hasan M. M.; Talukder, Shaon; Miyara, Akio

    2016-07-01

    The present research work observed the experimental and analytical results of two phase condensation heat transfer of the refrigerants R1234ze(E), R32, R410A, and R1234ze(E)/R32 mixtures inside a smooth horizontal tube. A water heated double tube horizontal heat exchanger with effective length of 3.6m and inner diameter of 4.35mm is used to take place the experiment. Mass flux and the saturation temperature are the design variables under which the experiment is carried out whose values varying from the range 160 to 400 Kg m-2s-1 and 30°C to 45°C, respectively. A new correlation for pure refrigerant has been proposed to predict the heat transfer inside a smooth horizontal tube by investigating the experimental data. The newly proposed correlation and some other existing correlations of condensation heat transfer for pure refrigerant have been used to predict the condensation heat transfer of R1234ze(E), R32, R410A and dimethyl ether (DME) and compared the results. The comparison allows that the proposed model of pure refrigerant offered a better performance for all the refrigerants. All the experimental data can be predicted within a 10.2% mean deviation by using the proposed correlation.

  13. Combined Cycle for Power Generation and Refrigeration Using Low Temperature Heat Sources

    OpenAIRE

    Vijay Chauhan; P. Anil Kishan; Sateesh Gedupudi

    2014-01-01

    A combined refrigeration and power cycle, which uses ammonia-water as the working fluid, is proposed by combining Rankine and vapour absorption cycles with an advantage of varying refrigeration capacity to power output ratio. The study investigates the usage of low temperature heat sources for the cycle operation. Results of parametric analysis are presented, which show the scope for optimization. Results of thermodynamic optimization of the cycle for second law efficiency performed using gen...

  14. Numerical simulation of the effects of a suction line heat exchanger on vapor compression refrigeration cycle performance

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ji Hwan; Park, Sang Goo; Sarker, Debasish [Pusan National University, Busan (Korea, Republic of); Chang, Keun Sun [Sunmoon University, Asan (Korea, Republic of)

    2012-04-15

    Most modern refrigerators incorporate heat transfer between the refrigerant in a capillary tube and the refrigerant in a suction line. This heat transfer is achieved by a non-adiabatic capillary tube called a capillary tube-suction line heat exchanger and is supposed to improve the performance of the small vapor compression refrigeration cycle by removing some enthalpy of the refrigerant at the evaporator entrance. To investigate the effects of this heat transfer on the refrigeration cycle, a computer program was developed based on conservation equations of mass, momentum, and energy. The non-adiabatic capillary tube model is based on a homogeneous two-phase flow model. The simulation results show that both the location and length of the heat exchange section influence the coefficient of performance (COP) as well as the cooling capacity. It is noteworthy that the influence was not monotonic; that is, the performance may be deteriorated under certain conditions.

  15. Quantum Stirling heat engine and refrigerator with single and coupled spin systems

    Science.gov (United States)

    Huang, Xiao-Li; Niu, Xin-Ya; Xiu, Xiao-Ming; Yi, Xue-Xi

    2014-02-01

    We study the reversible quantum Stirling cycle with a single spin or two coupled spins as the working substance. With the single spin as the working substance, we find that under certain conditions the reversed cycle of a heat engine is NOT a refrigerator, this feature holds true for a Stirling heat engine with an ion trapped in a shallow potential as its working substance. The efficiency of quantum Stirling heat engine can be higher than the efficiency of the Carnot engine, but the performance coefficient of the quantum Stirling refrigerator is always lower than its classical counterpart. With two coupled spins as the working substance, we find that a heat engine can turn to a refrigerator due to the increasing of the coupling constant, this can be explained by the properties of the isothermal line in the magnetic field-entropy plane.

  16. Current status of the problem of heat pumps and refrigerating devices

    Science.gov (United States)

    Vasiliev, L. L.

    2010-09-01

    In connection with the limited energy reserves in the Republic of Belarus, it is expedient to use sorption heat pumps and refrigerators in heating and refrigeration supply systems. Such heat engines possess a unique capability of utilizing the heat of low-temperature energy sources: water ponds, groundwater, and waste water and steam in combination with traditional heaters of rooms (boilers, furnaces, etc.). Adsorption reversible heat pumps developed at the A. V. Luikov Heat and Mass Transfer Institute of the National Academy of Sciences of Belarus make it possible to obtain 20 to 30 kW/m3 of thermal energy and up to 5 kW/m3 of cold. Such heat pumps save up to 15-20% of primary energy (fuel) for production of electricity, heat, and cold.

  17. Advanced Supermarket Refrigeration - Heat Recovery Systems. Annex 26. Final report. Volume 2. Country reports

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-04-01

    Annex 26 has produced three deliverables: (1) Workshop (October 2000) proceedings Stockholm, Sweden, on CD-ROM (HPP-AN26-1); (2) Final report, Volume 1, Executive Summary, as report (HPP-AN26-2); and (3) Final report, Volume 2, Country reports (described in this record). Each of these reports, available from the HPC, provide valuable information for practitioners (designers, installers) and manufacturers of supermarket refrigeration systems. Annex 26 is the first international project under the IEA Heat Pump Programme that links refrigeration and heat pump technology. Recovering heat from advanced supermarket refrigeration systems for space and water heating purposes seems obvious and is beneficial for owners and operators. Because there are world-wide a great number of supermarkets that offer frozen and chilled food and further growth of this sector may be expected, the amount of energy used for refrigeration is enormous and will likely increase substantially in the near future. Annex 26 analysed several advanced supermarket refrigeration systems and came to remarkable conclusions as far as energy conservation and TEWI reduction is concerned. The conclusions justify that advanced supermarket systems with heat recovery should receive great attention and support. And there is still further research needed in several areas. The Annex also included a thorough system cost analyses and proposals for cost reductions are given.

  18. Advanced Supermarket Refrigeration - Heat Recovery Systems. Annex 26. Final report. Volume 1. Executive summary

    Energy Technology Data Exchange (ETDEWEB)

    Baxter, Van D. (ed.) [Oak Ridge National Laboratory ORNL, Oak Ridge, TN (United States)

    2003-04-01

    Annex 26 has produced three deliverables: (1) Workshop (October 2000) proceedings Stockholm, Sweden, on CD-ROM (HPP-AN26-1); (2) Final report, described in this record; and (3) Final report, Volume 2, Country reports, on CD-ROM (HPP-AN26-3). Each of these reports, available from the HPC, provide valuable information for practitioners (designers, installers) and manufacturers of supermarket refrigeration systems. Annex 26 is the first international project under the IEA Heat Pump Programme that links refrigeration and heat pump technology. Recovering heat from advanced supermarket refrigeration systems for space and water heating purposes seems obvious and is beneficial for owners and operators. Because there are world-wide a great number of supermarkets that offer frozen and chilled food and further growth of this sector may be expected, the amount of energy used for refrigeration is enormous and will likely increase substantially in the near future. Annex 26 analysed several advanced supermarket refrigeration systems and came to remarkable conclusions as far as energy conservation and TEWI reduction is concerned. The conclusions justify that advanced supermarket systems with heat recovery should receive great attention and support. And there is still further research needed in several areas. The Annex also included a thorough system cost analyses and proposals for cost reductions are given.

  19. Heat transfer in forced convection boiling of oil-non-azeotropic binary refrigerant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sami, S.M.; Tulej, P.; Fang, L. (Moncton Univ., NB (Canada))

    1993-12-01

    In this paper, the results of the heat transfer, forced convection, boiling characteristics of non-azeotropic refrigerant mixtures and oil are presented. This includes heat transfer coefficients for pure and binary mixtures under boiling conditions outside enhanced surface tubing. Local convective heat transfer coefficients have been determined using a modified Wilson-plot technique. Heat transfer correlations were established as a function of the binary mixture mass flow rate, and oil concentration, as well as key flow parameters. (author)

  20. Effect of heat transfer on the performance of thermoelectric generator-driven thermoelectric refrigerator system

    Science.gov (United States)

    Chen, Lingen; Meng, Fankai; Sun, Fengrui

    2012-01-01

    A model of thermoelectric generator-driven thermoelectric refrigerator with external heat transfer is proposed. The performance of the combined thermoelectric refrigerator device obeying Newton's heat transfer law is analyzed using the combination of finite time thermodynamics and non-equilibrium thermodynamics. Two analytical formulae for cooling load vs. working electrical current, and the coefficient of performance (COP) vs. working electrical current, are derived. For a fixed total heat transfer surface area of four heat exchangers, the allocations of the heat transfer surface area among the four heat exchangers are optimized for maximizing the cooling load and the coefficient of performance (COP) of the combined thermoelectric refrigerator device. For a fixed total number of thermoelectric elements, the ratio of number of thermoelectric elements of the generator to the total number of thermoelectric elements is also optimized for maximizing both the cooling load and the COP of the combined thermoelectric refrigerator device. The influences of thermoelectric element allocation and heat transfer area allocation are analyzed by detailed numerical examples. Optimum working electrical current for maximum cooling load and COP at different total number of thermoelectric elements and different total heat transfer area are obtained, respectively.

  1. Wet compression versus dry compression in heat pumps working with pure refrigerants or non-azeotropic binary mixtures for different heating applications

    Energy Technology Data Exchange (ETDEWEB)

    Vorster, P.P.J.; Meyer, J.P. [Rand Afrikaans University, Auckland Park (South Africa). Dept. of Mechanical Engineering

    2000-06-01

    Wet compression versus dry compression in heat pumps working with pure refrigerants or non-azeotropic binary mixtures is investigated in this paper. In total 34 pure refrigerants as well as 31 non-azeotropic binary mixtures at different concentrations are considered. This resulted in approximately 300 different mixtures being analysed. The pure refrigerants were analysed for three different heating applications found in practice: the heating of swimming pool water, heating air for interior space heating, and the heating of water for domestic use. The investigation was conducted with cycle analyses calculating performances at different wet and dry compressor inlet values. Use was made of thermodynamic refrigerant properties calculated from a computer database. It was concluded that for both pure and non-azeotropic refrigerants analysed, all those with re-entrant saturation vapour lines produce better heating COPs when the refrigerant is superheated before entering the compressor. Only a few of the refrigerants with bell-shaped T-s curves consistently produce higher heating COPs when wet compression is used. However, their heating capacities decrease while the compressor displacement rates increase. It was concluded that in general dry compression is more favourable than wet compression. From the few exceptions that do exist, some manage to produce very high COP{sub h}'s while retaining competitive heating capacities. A by-product of this study is that from the vast amount of refrigerant mixtures analysed valuable knowledge was gathered regarding refrigerants not commonly used in the applications considered. (author)

  2. Performance investigation of a waste heat driven pressurized adsorption refrigeration cycle

    Science.gov (United States)

    Habib, K.

    2015-12-01

    This article presents performance investigation of a waste heat driven two bed pressurised adsorption refrigeration system. In this study, highly porous activated carbon (AC) of type Maxsorb III has been selected as adsorbent while n-butane, R-134a, R410a, R507a and carbon dioxide (CO2) are chosen as refrigerants. All the five refrigerants work at above atmospheric pressure. Among the five pairs studied, the best pairs will be identified which will be used to provide sufficient cooling capacity for a driving heat source temperature above 60°C. Results indicate that for a driving source temperature above 60°C, AC-R410a pair provides highest cooling capacity while AC-CO2 pairs works better when the heat source temperature falls below 60°C.

  3. Operational characteristics of single-particle heat engines and refrigerators with time-asymmetric protocol

    Science.gov (United States)

    Pal, P. S.; Saha, Arnab; Jayannavar, A. M.

    2016-09-01

    We have studied the single-particle heat engine and refrigerator driven by time-asymmetric protocol of finite duration. Our system consists of a particle in a harmonic trap with time-periodic strength that drives the particle cyclically between two baths. Each cycle consists of two isothermal steps at different temperatures and two adiabatic steps connecting them. The system works in irreversible mode of operation even in the quasistatic regime. This is indicated by finite entropy production even in the large cycle time limit. Consequently, Carnot efficiency for heat engine or Carnot coefficient of performance (COP) for refrigerators is not achievable. We further analyzed the phase diagram of heat engines and refrigerators. They are sensitive to time-asymmetry of the protocol. Phase diagram shows several interesting features, often counterintuitive. The distribution of stochastic efficiency and COP is broad and exhibits power-law tails.

  4. A study on multifunction heat pipe type high efficient adsorption refrigerator using compound adsorbent-ammonia

    Institute of Scientific and Technical Information of China (English)

    LU Zisheng; WANG Ruzhu; WANG Liwei; CHEN Chuanjuan

    2006-01-01

    A multifunction heat pipe adsorption refrigerator is designed, which uses solidified compound adsorbent of CaCl2 and activated carbon as adsorbent. Two work conditions, ice-maker driven by the exhaust heat from diesel engine and air-condi- tioning powered by solar energy, are studied. SCP (specific cooling power) and COP (coefficient of per- formance) for different conditions are analyzed. The optimum average SCP and COP for the refrigerator powered by waste heat of diesel engine are 770.4 W/kg and 0.39 at about -20℃ evaporating tem- perature. The optimum average SCP and COP for the refrigerator powered by solar energy are 524.2 W/kg and 0.27 at about 5.6℃ evaporating tempera- ture.

  5. Exergy analysis of heating, refrigerating and air conditioning methods and applications

    CERN Document Server

    Dincer, Ibrahim

    2015-01-01

    Improve and optimize efficiency of HVAC and related energy systems from an exergy perspective. From fundamentals to advanced applications, Exergy Analysis of Heating, Air Conditioning, and Refrigeration provides readers with a clear and concise description of exergy analysis and its many uses. Focusing on the application of exergy methods to the primary technologies for heating, refrigerating, and air conditioning, Ibrahim Dincer and Marc A. Rosen demonstrate exactly how exergy can help improve and optimize efficiency, environmental performance, and cost-effectiveness. The book also discusses the analysis tools available, and includes many comprehensive case studies on current and emerging systems and technologies for real-world examples. From introducing exergy and thermodynamic fundamentals to presenting the use of exergy methods for heating, refrigeration, and air conditioning systems, this book equips any researcher or practicing engineer with the tools needed to learn and master the application of exergy...

  6. Numerical simulation of simultaneous heat and moisture transfer in a domestic refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Laguerre, O.; Benamara, S. [Cemagref, Refrigeration Process Engineering, Cemagref, BP. 44, 92163 Antony Cedex (France); Flick, D. [AgroParisTech, UMR 1145 Genie Industriel Alimentaire, F-91300 Massy (France)

    2010-11-15

    This study was carried out in order to gain a better insight into evaporation and condensation phenomena due to natural convection in a domestic refrigerator without a fan. A model refrigerator loaded with moist cylinders was studied initially. CFD simulations took into account air flow, heat transfer (convection, conduction and radiation) and mass transfer (water evaporation and condensation). The numerical results were compared with the experimental values. The position where evaporation and condensation occur was generally well predicted in spite of the fact that simulation underestimates the experimental values. The numerical methodology developed was then applied to a real refrigerator loaded with unpackaged products (susceptible to dehydration). The same phenomena as those in the model refrigerator were observed: condensation on the product located near to the evaporator, dehydration of the products located near the door and at the top. (author)

  7. Cooling load optimization of an irreversible refrigerator with combined heat transfer

    Directory of Open Access Journals (Sweden)

    M. El Haj Assad

    2013-01-01

    Full Text Available In this work a mathematical model to study the performance of an irreversible refrigerator has been presented with the consideration of heat exchange by combined convection and radiation. The external irreversibility effects due to finite rate heat transfer as well as the effects of internal dissipations have been considered in the analysis. The relation between the cooling load and the coefficient of performance of the refrigerator has been derived. Furthermore an expression for the maximum cooling rate has been derived. The parameters that affect the cooling load have been investigated. The cooling load has been discussed and the effect of internal irreversibility has been investigated.

  8. Low GWP Refrigerants Modelling Study for a Room Air Conditioner Having Microchannel Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Bhandari, Mahabir S [ORNL

    2016-01-01

    Microchannel heat exchangers (MHX) have found great successes in residential and commercial air conditioning applications, being compact heat exchangers, to reduce refrigerant charge and material cost. This investigation aims to extend the application of MHXs in split, room air conditioners (RAC), per fundamental heat exchanger and system modelling. For this paper, microchannel condenser and evaporator models were developed, using a segment-to-segment modelling approach. The microchannel heat exchanger models were integrated to a system design model. The system model is able to predict the performance indices, such as cooling capacity, efficiency, sensible heat ratio, etc. Using the calibrated system and heat exchanger models, we evaluated numerous low GWP (global warming potential) refrigerants. The predicted system performance indices, e.g. cooling efficiency, compressor discharge temperature, and required compressor displacement volume etc., are compared. Suitable replacements for R22 and R-410A for the room air conditioner application are recommended.

  9. Evaluation of non-azeotropic mixtures containing HFOs as potential refrigerants in refrigeration and high-temperature heat pump systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the increasing environmental concern on global warming, hydrofluoro-olefin (HFOs), possessing low GWP, has attracted great attention of many researchers recently. In this study, non-azeotropic mixtures composed of HFOs (HFO-1234yf, HFO-1234ze(z), HFO-1234ze(e) and HFO-1234zf) are developed to substitute for HFC-134a and CFC-114 in air-conditioning and high-temperature heat pump systems, respectively. The cycle performances were evaluated by an improved theoretical cy-cle evaluation methodology. The results showed that all the mixtures proposed herein were favorable refrigerants with excel-lent thermodynamic cycle performances. M1A presented lower discharge temperature and pressure ratio and higher COPc than that of HFC-134a. The volumetric cooling capacity was similar to HFC-134a. It can be served as a good environmentally friendly alternative to replace HFC-134a. M3H delivered similar discharge temperature as CFC-114 did. And the COPh was 3% higher. It exhibits excellent cycle performance in high-temperature heat pump and is a promising refrigerant to substitute for CFC-114. And the gliding temperature differences enable them to exhibit better coefficient of performance by matching the sink/source temperature in practice. Because the toxicity, flammability and other properties are not investigated in detail, ex-tensive toxicity and flammability testing needs to be conducted before they are used in a particular application.

  10. Reprint of : Three-terminal heat engine and refrigerator based on superlattices

    Science.gov (United States)

    Choi, Yunjin; Jordan, Andrew N.

    2016-08-01

    We propose a three-terminal heat engine based on semiconductor superlattices for energy harvesting. The periodicity of the superlattice structure creates an energy miniband, giving an energy window for allowed electron transport. We find that this device delivers a large power, nearly twice than the heat engine based on quantum wells, with a small reduction of efficiency. This engine also works as a refrigerator in a different regime of the system's parameters. The thermoelectric performance of the refrigerator is analyzed, including the cooling power and coefficient of performance in the optimized condition. We also calculate phonon heat current through the system and explore the reduction of phonon heat current compared to the bulk material. The direct phonon heat current is negligible at low temperatures, but dominates over the electronic at room temperature and we discuss ways to reduce it.

  11. Optimal Cooling Load and COP Relationship of a Four-Heat-Reservoir Endoreversible Absorption Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Chih Wu

    2004-06-01

    Full Text Available Abstract: On the basis of a four-heat-reservoir endoreversible absorption refrigeration cycle model, another linear heat transfer law [i.e., the heat-flux] is adopted, the fundamental optimal relation between the coefficient of performance (COP and the cooling load, as well as the maximum cooling load and the corresponding COP of the cycle coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics or thermodynamic optimization. The optimal distribution of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of an absorption refrigeration cycle.

  12. 49 CFR 176.93 - Vehicles having refrigerating or heating equipment.

    Science.gov (United States)

    2010-10-01

    ... HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS... Transported on Board Ferry Vessels § 176.93 Vehicles having refrigerating or heating equipment. (a) A... (flammable gas) material, or diesel oil as fuel, may be transported on a ferry vessel. However, the...

  13. Heating, Air Conditioning and Refrigeration. Vocational Education Curriculum Guide. Industrial and Technical Education.

    Science.gov (United States)

    West Virginia State Vocational Curriculum Lab., Cedar Lakes.

    This curriculum guide contains 17 units that provides the basic curriculum components required to develop lesson plans for the heating, air conditioning, and refrigeration curriculum. The guide is not intended to be a complete, self-contained curriculum, but instead provides the teacher with a number of informational items related to the learning…

  14. Adapting CHP Software to suit the modelling of heat pump and refrigeration systems

    NARCIS (Netherlands)

    Verschoor, M.J.E.

    1998-01-01

    The role of heat pumps and refrigeration machines as integrated parts of energy supply systems is increasing as a result of the search for systems which supply the desired amounts and types of energy in an energy-efficient manner. Tools to support engineers in designing, analysing and optimising suc

  15. Adapting CHP Software to suit the modelling of heat pump and refrigeration systems

    NARCIS (Netherlands)

    Verschoor, M.J.E.

    1998-01-01

    The role of heat pumps and refrigeration machines as integrated parts of energy supply systems is increasing as a result of the search for systems which supply the desired amounts and types of energy in an energy-efficient manner. Tools to support engineers in designing, analysing and optimising

  16. TRANSIENT AND STEADY STATE STUDY OF PURE AND MIXED REFRIGERANTS IN A RESIDENTIAL HEAT PUMP

    Science.gov (United States)

    The report gives results of an experimental and theoretical investigation of the transient and steady state performance of a residential air-conditioning/heat pump (AC/HP) operating with different refrigerants. (NOTE: The project was motivated by environmental concerns related to...

  17. TRANSIENT AND STEADY STATE STUDY OF PURE AND MIXED REFRIGERANTS IN A RESIDENTIAL HEAT PUMP

    Science.gov (United States)

    The report gives results of an experimental and theoretical investigation of the transient and steady state performance of a residential air-conditioning/heat pump (AC/HP) operating with different refrigerants. (NOTE: The project was motivated by environmental concerns related to...

  18. Utilization of process energy from supermarket refrigeration systems. Coupling of cooling and heating; Prozessenergienutzung von Supermarktkaelteanlagen. Kaelte-Waerme-Kopplung

    Energy Technology Data Exchange (ETDEWEB)

    Wirsching, Alexander [TEKO Gesellschaft fuer Kaeltetechnik mbH, Altenstadt (Germany). Technologie und Kommunikation

    2010-03-15

    The efficiency is defined as the relation between utility and expenditure. Thus, it is obvious for the specialist of refrigeration to tackle with the expenditure (energy consumption) since the utilization conventionally is defined as the produced/need cooling performance of a refrigeration plant. If refrigeration plants are regarded according to their function (withdrawal of heat from a refrigeration chamber and delivery to the environment), the heating system is the producer of the requirement for cooling in 'the winter' (heating season). Thus, the refrigeration plant perhaps already has a marvellous efficiency, and the separate heating system too - however in interaction. The broad view moves into the focus. The possible approaches and effects are described in the contribution under consideration using the example of a Discount supermarket with a sales area of 800 square meters and a requirement of cooling of more than 30 kW.

  19. 2012 International Conference on Medical Physics and Biomedical Engineering Thermal Economic Analysis on LiBr Refrigeration -Heat Pump System Applied in CCHP System

    Science.gov (United States)

    Zhang, CuiZhen; Yang, Mo; Lu, Mei; Zhu, Jiaxian; Xu, Wendong

    LiBr refrigeration cooling water contains a lot of low-temperature heat source, can use this part of the heat source heat boiler feed water. This paper introduced LiBr refrigeration - heat pump system which recovery heat of the LiBr refrigeration cooling water by heat pump system to heat the feed water of boiler. Hot economic analysis on the system has been performed based on the experimental data. Results show that LiBr refrigeration-heat pump system brings 26.6 percent decrease in primary energy rate consumption comparing with the combined heat and power production system(CHP) and separate generation of cold;

  20. Commercial Refrigeration: Heat Transfer Optimization and Energy Reduction, Measurement and Verification of a Liquid Refrigerant Pump System Retrofit

    Energy Technology Data Exchange (ETDEWEB)

    Gaul, Chris [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sheppy, Michael [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-03-22

    This study describes the test results of a Refrigerant Pump System integrated into a commercial supermarket direct expansion (DX) vapor compression refrigeration system. The Liquid Refrigerant Pump System retrofit (patent-pending; application number 13/964,198) was introduced to NREL in August 2014 by CTA Architects Engineers.

  1. Refrigeration. Heat Transfer. Part I: Evaporators and Condensers

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation.......The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation....

  2. Two-phase Flow Ejector as Water Refrigerant by Using Waste Heat

    Science.gov (United States)

    Yamanaka, H.; Nakagawa, M.

    2013-04-01

    Energy saving and the use of clean energy sources have recently become significant issues. It is expected that clean energy sources such as solar panels and fuel cells will be installed in many private dwellings. However, when electrical power is generated, exhaust heat is simultaneously produced. Especially for the summer season, the development of refrigeration systems that can use this waste heat is highly desirable. One approach is an ejector that can reduce the mechanical compression work required in a normal refrigeration cycle. We focus on the use of water as a refrigerant, since this can be safely implemented in private dwellings. Although the energy conversion efficiency is low, it is promising because it can use heat that would otherwise be discarded. However, a steam ejector refrigeration cycle requires a large amount of energy to change saturated water into vapour. Thus, we propose a more efficient two-phase flow ejector cycle. Experiments were carried out in which the quality of the two-phase flow from a tank was varied, and the efficiency of the ejector and nozzle was determined. The results show that a vacuum state can be achieved and suction exerted with a two-phase flow state at the ejector nozzle inlet.

  3. Carbon dioxide as refrigerant for tap water heat pumps: A comparison with the traditional solution

    Energy Technology Data Exchange (ETDEWEB)

    Cecchinato, Luca; Corradi, Marco; Fornasieri, Ezio; Zamboni, Lorenzo [Dipartimento di Fisica Tecnica, Universita degli Studi di Padova, Via Venezia, 1 I-35131 Padova (Italy)

    2005-12-01

    Increased concern about the environmental impact of the refrigeration technology is leading toward design solutions aimed at improving the energy efficiency of the related applications, using eco-friendly refrigerants, i.e. ozone-friendly and with the least possible global warming potential (GWP). In this respect, carbon dioxide (ASHRAE R744) is seen today as one of the most promising refrigerants and is raising great interest in industrial and scientific fields. In the present work, the plant options are investigated, which are related to the design of air/water heat pumps for tap water using CO{sub 2}. A comparison is made, in terms of energy efficiency, between a system working with CO{sub 2} and a similar one working with HFC R134a; such a comparison is carried out by means of a simulation model of a refrigerating machine/heat pump, characterized by a detailed representation of the heat exchangers, based on their subdivision into elementary volumes. Results show that carbon dioxide is an interesting substitute for synthetic fluids, if the design of the system is focused to take advantage of its properties. (author)

  4. Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan ZHANG; Xingqun ZHANG; Yunguang CHEN; Xiuling YUAN

    2008-01-01

    Based on experimental results of ternary non-azeotropic refrigerant mixture R417A flowing and boiling in one smooth and two internally grooved horizontal tubes with different geometrical parameters, a boiling heat transfer correlations was developed for refrigerant mix-tures flowing inside micro-fin tubes by applying the enhancement factor in the present modified-Kattan model which was modified by the experimental data of R417A in a smooth tube. The comparison between the calculation and the experimental results indicates that the prediction by the present correlations is in good agreement with the experiment of refrigerant mixtures inside different micro-fin tubes with a standard deviation of ± 30% for vapor qualities below 80%.

  5. Market Assessment for Residential Refrigerator-Freezer with Novel Rotating Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Sikes, Karen [CSRA International, Inc., Fairfax, VA (United States); Blackburn, Julia [CSRA International, Inc., Fairfax, VA (United States); Grubbs, Tyler [CSRA International, Inc., Fairfax, VA (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Momen, Ayyoub [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-01

    Despite a steady record of energy efficiency improvements in residential refrigerators and freezers over recent decades, these products still account for 4% of the site energy consumption for the average U.S. household. The Oak Ridge National Laboratory (ORNL) – along with partners Sandia National Laboratories (SNL) and the University of Maryland – are pursuing further efficiency improvements in this market sector by using a novel/prototype rotating heat exchanger (RHX) based on a Sandia Cooler technology as an evaporator in a residential refrigerator-freezer. The purpose of this study is to investigate the market potential of refrigerator-freezer products equipped with RHX evaporators in the United States, including projections of maximum annual market share and unit shipments and maximum direct and indirect job creation.

  6. Environmental relevance of natural refrigerants in heat pumps; Umweltrelevanz natuerlicher Kaeltemittel in Waermepumpen

    Energy Technology Data Exchange (ETDEWEB)

    Zogg, M. [Bundesamt fuer Energie, Oberburg (Switzerland)

    2000-04-01

    On behalf of the Federal Office for energy in a global ecological balance the environmental compatibility of natural refrigerants is compared with the influence of fluorocarbons for heat pumps, water chillers, brine chillers and the supermarket refrigeration. In this paper the environmental relevance of the use of the natural refrigerants propane and CO{sub 2} is compared with fluorocarbons R 134a, R 407C, 404A and Isceon 59. (orig.) [German] Im Auftrag des Bundesamts fuer Energie wurden in einer umfassenden Oekobilanz die Umweltvertraeglichkeit natuerlicher Kaeltemittel mit den heute ueblichen Fluorkohlenwasserstoffen fuer Waermepumpen, Kaltwassersaetze, Solesaetze und die Supermarktkuehlung verglichen. In diesem Beitrag wird daraus die Umweltrelevanz der Verwendung der natuerlichen Kaeltemittel Propan und CO{sub 2} anstelle der Fluorkohlenwasserstoffe R 134a, R 407C, R 404A und Isceon 59 in Waermepumpen aufgezeigt. (orig.)

  7. A Cooling System for an Automobile Based on Vapour Absorption Refrigeration Cycle Using Waste Heat of an Engine.

    Directory of Open Access Journals (Sweden)

    Satish K. Maurya

    2014-03-01

    Full Text Available Now a days the air conditioning system of cars is mainly uses “Vapour Compression Refrigerant System” (VCRS which absorbs and removes heat from the interior of the car that is the space to be cooled and rejects the heat to atmosphere. In vapour compression refrigerant system, the system utilizes power from engine shaft as the input power to drive the compressor of the refrigeration system, hence the engine has to produce extra work to run the compressor of the refrigerating system utilizing extra amount of fuel. This loss of power of the vehicle for refrigeration can be neglected by utilizing another refrigeration system i.e. a “Vapour Absorption Refrigerant System”. As well known thing about VAS that these machines required low grade energy for operation. Hence in such types of system, a physicochemical process replaces the mechanical process of the Vapour Compression Refrigerant System by using energy in the form of heat rather than mechanical work. This heat obtained from the exhaust of high power internal combustion engines.

  8. Theoretical study of heat pump system using CO2/dimethylether as refrigerant

    Directory of Open Access Journals (Sweden)

    Fan Xiao-Wei

    2013-01-01

    Full Text Available Nowadays, HCFC22 is widely used in heat pump systems in China, which should be phased out in the future. Thus, eco-friendly mixture CO2/dimethylether is proposed to replace HCFC22. Compared with pure CO2 and pure dimethylether, the mixture can reduce the heat rejection pressure, and suppress the flammability and explosivity of pure dimethylether. According to the Chinese National Standards on heat pump water heater and space heating system, performances of the subcritical heat pump system are discussed and compared with those of the HCFC22 system. It can be concluded that CO2 /dimethylether mixture works efficiently as a refrigerant for heat pumps with a large heat-sink temperature rise. When mass fraction of dimethylether is increased, the heat rejection pressure is reduced. Under the nominal working condition, there is an optimal mixture mass fraction of 28/72 of CO2/dimethylether for water heater application under conventional condensation pressure, 3/97 for space heating application. For water heater application, both the heating coefficient of performance and volumetric heating capacity increase by 17.90% and 2.74%, respectively, compared with those of HCFC22 systems. For space heating application, the heating coefficient of performance increases by 8.44% while volumetric heating capacity decreases by 34.76%, compared with those of HCFC22 systems. As the superheat degree increases, both the heating coefficient of performance and volumetric heating capacity tend to decrease.

  9. High Effectiveness Heat Exchanger for Cryogenic Refrigerators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an innovative high performance cryogenic heat exchanger manufactured of titanium by photo-etching and diffusion bonding. This is a parallel plate design...

  10. Fermilab energy saver refrigeration system tests

    Energy Technology Data Exchange (ETDEWEB)

    Theilacker, J.; Rode, C.; Makara, J.; Richied, D.; Leninger, M.; Ferry, R.; Mizicko, D.; Misek, J.

    1981-06-01

    The Energy Saver Refrigeration System is based on the concept of a central helium liquefier (5000 l/hr) providing liquid to 24 satellite refrigerators (966 W at 4.6/degree/K), which operate as amplifiers with a gain of 12. This concept was tested, cooling two 125 m long strings of superconducting magnets. The test was run using one satellite refrigerator operating as the ''central liquefier'', shipping liquid helium through a 250 m long transfer line to a second satellite refrigerator, which in turn cooled the magnets. In addition to testing the satellite concept, the heat loads of the magnets and transfer line were also measured. 3 refs.

  11. Heat Transfer in Nucleate Pool Boiling of Binary and Ternary Refrigerant Mixtures

    Institute of Scientific and Technical Information of China (English)

    赵耀华; 刁彦华; 鹤田隆治; 西川日出男

    2004-01-01

    Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants, HFC-134a, HFC-32, and HFC-125, their binary and ternary mixtures under saturated conditions at 0.9MPa. Compared to pure components, both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixture, the accuracy of the correlations varied considerably with mixtures and the heat flux. Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome. For ternary mixture, the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points, and their concentration difference had important effects on boiling heat transfer coefficients.

  12. Trends in the development of fluid-operated heat transfer devices for refrigerant feed pumps and heat pumps using non-azeotropic binary-fluid refrigerants with special regard to the problem of CFCs. Entwicklungstendenzen fluessigkeitsbeaufschlagter Waermeuebertrager fuer Kaelte- und Waermepumpenanlagen mit nichtazeotropen Zweistoffkaeltemitteln unter Beruecksichtigung der FCKW-Problematik

    Energy Technology Data Exchange (ETDEWEB)

    Goebel, F.

    1991-06-12

    In the construction of binary-fluid refrigerant heat transfer devices as evaporators and condensers in heat pumps for the cooling of waste heat flows, the hydraulic diametre of the media flows is decisive. By means of the flow against refrigerant-carrying tubes, heat transfer systems can be assigned to different categories. The heat transfer in a heat exchanger is determined by quantities such as water speed and flow conditions in refrigerant-carrying tubes. (VT)

  13. Properties of new refrigerants and predictions for condensation heat transfer enhancement with low-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Stegou-Sagia, A. [National Technical University of Athens (Greece). Dept. of Mechanical Engineering

    1996-12-01

    The present article provides a review of thermophysical properties research of environmentally acceptable refrigerants. In recent years, it has become evident that common CFC type refrigerants can cause serious environmental damage when released into the atmosphere. The group of HFCs (HFC-32, HFC-125, HFC-134a, HFC-152a) with no chlorine atom in their chemical formulae and quite short atmospheric lifetime may be promising alternatives to CFCs. A compilation of properties is given which may be used to obtain arithmetic expressions for the vapour pressure, saturated liquid density, viscosity, latent heat of vaporization, saturated liquid thermal conductivity, and surface tension of these hydrofluorocarbons. For easily available comparisons, the results are presented in diagrams illustrating the dependence of thermophysical data on temperature at the saturated state. (author)

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

    Science.gov (United States)

    Imai, Yosuke; Ohashi, Toshinori; Okamoto, Hiroaki; Hihara, Eiji; Kawakami, Ryuichiro

    On conventional gas heat pump(GHP), waste heat from gas engine that uses as driving source is emitted into outside. So from the standpoint of efficient use of waste heat, it is assumed that waste heat from gas engine is used as driving source of absorption chiller, and high temperature condensate refrigerant in GHP is subcooled to middle temperature by cold source from absorption cycle, and as a result, GHP makes more efficiency. However, in equipping GHP with absorption cycle, downsizing and high-efficiency of absorption cycle is required. In this study, air-cooled subcooled adiabatic absorber is focused and physical phenomenon in it is analyzed, and finally one perception of the optimized designing is shown.

  15. Simulation studies of the behaviour of a heat pipe-assisted solar absorption refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hindi, R.R.; Khalifa, A.M.A.; Akyurt, M.

    1988-01-01

    Simulation work on an intermittent-duty, heat pipe-assisted, solar-operated aqua-ammonia absorption refrigerator is reported. The low-thermal mass collector is the integral evaporator of an acetone-copper heat pipe which delivers the collected energy isothermally to a distant generator. The shell-and-tube type generator receives the energy by vapour condensation. The condenser is air cooled. A separate R-22/steel heat-pipe system serves to cool the absorber tanks via a radiation/convection panel. Heat and mass balances are outlined on several units. The resulting equations are solved for day and night operation. It is concluded that both the initial solution (absorbent) concentration and the absorber temperature must be kept low for adequate ice production.

  16. REACH. Refrigeration Units.

    Science.gov (United States)

    Snow, Rufus; And Others

    As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of refrigeration. The instructional units focus on refrigeration fundamentals, tubing and pipe, refrigerants, troubleshooting, window air conditioning, and…

  17. Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load

    Science.gov (United States)

    Garcia, Sam; Meagher, Daniel; Linza, Robert; Saheli, Fariborz; Vargas, Gerardo; Lauterbach, John; Reis, Carl; Ganni, Venkatarao (Rao); Homan, Jonathan

    2008-01-01

    NASA s Johnson Space Center (JSC) Building 32 houses two large thermal-vacuum chambers (Chamber A and Chamber B). Within these chambers are liquid nitrogen shrouds to provide a thermal environment and helium panels which operate at 20K to provide cryopumping. Some amount of air leakage into the chambers during tests is inevitable. This causes "air fouling" of the helium panel surfaces due to the components of the air that adhere to the panels. The air fouling causes the emittance of the helium panels to increase during tests. The increase in helium panel emittance increases the heat load on the helium refrigerator that supplies the 20K helium for those panels. Planning for thermal-vacuum tests should account for this increase to make sure that the helium refrigerator capacity will not be exceeded over the duration of a test. During a recent test conducted in Chamber B a known-size air leak was introduced to the chamber. Emittance change of the helium panels and the affect on the helium refrigerator was characterized. A description of the test and the results will be presented.

  18. Prediction of two-phase pressure drop in heat exchanger for mixed refrigerant Joule-Thomson cryocooler

    Science.gov (United States)

    Ardhapurkar, P. M.; Atrey, M. D.

    2015-12-01

    The overall efficiency of a mixed refrigerant Joule-Thomson (MR J-T) cryocooler is governed by the performance of the recuperative heat exchanger. In the heat exchanger, the hot stream of the mixed refrigerant undergoes condensation at high pressure while the cold stream gets evaporated at low pressure. The pressure drop in the low pressure stream is crucial since it directly influences the achievable refrigeration temperature. However, experimental and theoretical studies related to two-phase pressure drop in mixtures at cryogenic temperatures, are limited. Therefore, the design of an efficient MR J-T cryocooler is a challenging task due to the lack of predictive tools. In the present work, the existing empirical correlations, which are commonly used for the prediction of pressure drop in the case of pure refrigerants, evaporating at near ambient conditions, are assessed for the mixed refrigerants. Experiments are carried out to measure the overall pressure drop in the evaporating cold stream of the tube-in-tube helically coiled heat exchanger. The predicted frictional pressure drop in the heat exchanger is compared with the experimental data. The suggested empirical correlations can be used to predict the hydraulic performance of the heat exchanger.

  19. Thermodynamic analysis of a refrigeration cycle using regenerative heat exchanger - suction/liquid line

    Energy Technology Data Exchange (ETDEWEB)

    Tebchirani, Tarik Linhares; Matos, Rudmar Serafim [Pos graduate Programme in Mechanical Engineering (PGMEC), Universidade Federal do Parana, Curitiba, PR (Brazil)], e-mails: tarik@utfpr.edu.br, rudmar@demec.ufpr.br

    2010-07-01

    This paper presents results from thermodynamic comparison of a conventional compression cycle and a steam cycle that uses a heat exchanger countercurrent (liquid line/suction line) in an air conditioning system split. The main objective is to study the relationship between the COP and the mass variation of refrigerant to the effectiveness of the heat exchanger. The papers presented in the literature discuss the matter in a theoretical way, are summarized in tables of rare loss statements without specification of methods. The methodology of work is based on testing of an air conditioner operating conventionally and also with the heat exchanger for the determination of values and parameters of interest. The tests were performed in a thermal chamber with temperature controlled and equipped with a data acquisition system for reading and storage results. The refrigerant was R22. Besides making possible an assessment of the feasibility of cost-benefit thermodynamics, it is suggested a different method for installing the equipment type split. (author)

  20. PROCESSES OF HEAT-MASS-TRANSFER IN APPARATUS OF SOLAR ABSORBING REFRIGERATION SYSTEMS

    Directory of Open Access Journals (Sweden)

    Doroshenko A.V.

    2014-12-01

    Full Text Available Ideology of development of the solar refrigeration systems and systems of air-conditioning, based on the use of absorbing cycle and solar energy for the regeneration of absorbent solution, is presented in the article. The processes of joint heat-mass-transfer are considered in the direct and indirect types of evaporated coolers taking into account the phenomenon of re-condensation of aquatic steams at the low temperature evaporated cooling of environments. The pre-liminary analysis of possibilities of the solar systems is executed as it applies in relation to the tasks of cooling of envi-ronments and air-conditioning systems.

  1. A Comparative Cycle and Refrigerant Simulation Procedure Applied on Air-Water Heat Pumps

    DEFF Research Database (Denmark)

    Mader, Gunda; Palm, Björn; Elmegaard, Brian

    2012-01-01

    the evaluation to a single set of components. A special focus is on the heat exchanger sizes as a dominant influence on the cycle efficiency. Varying sizes are taken into account using a design of experiment factorization to determine a quadratic regression model for the energy efficiency. In combination...... with component cost correlations a constrained non-linear optimization problem is formulated and solved. Strengths and weaknesses of the proposed procedure are discussed in regard of its ability to help in systematically identifying promising combinations of cycle layout and refrigerant....

  2. Solar-driven absorption refrigeration system with heating support; Solarbetriebene Absorptions-Kaeltemaschine mit Heizungsunterstuetzung

    Energy Technology Data Exchange (ETDEWEB)

    Hilgenberg, Ch. [Ingenieurbuero IEM AG, Gwatt-Thun (Switzerland)

    2004-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project involving the replacement of a 250 kW air-conditioning system at a branch of the Bernese Cantonal Bank in Thun, Switzerland. The new system is described, which provides partial air-conditioning using two mini-absorber machines with a total capacity of 92 kW. Part of the heat needed for the absorber refrigeration machines is provided in summer by 100 m{sup 2} of solar collectors. The results of monitoring and measurements made in 2002 and 2003 are presented and commented on. The main arguments for the use of solar heat as a means of generating cold are presented, and the use of the solar energy to provide heating and hot water generation in the transition period between summer and winter is mentioned. Public interest in this innovative use of solar energy is commented on.

  3. Numerical studies on sizing/ rating of plate fin heat exchangers for a modified Claude cycle based helium liquefier/ refrigerator

    Science.gov (United States)

    Goyal, M.; Chakravarty, A.; Atrey, M. D.

    2017-02-01

    Performance of modern helium refrigeration/ liquefaction systems depends significantly on the effectiveness of heat exchangers. Generally, compact plate fin heat exchangers (PFHE) having very high effectiveness (>0.95) are used in such systems. Apart from basic fluid film resistances, various secondary parameters influence the sizing/ rating of these heat exchangers. In the present paper, sizing calculations are performed, using in-house developed numerical models/ codes, for a set of high effectiveness PFHE for a modified Claude cycle based helium liquefier/ refrigerator operating in the refrigeration mode without liquid nitrogen (LN2) pre-cooling. The combined effects of secondary parameters like axial heat conduction through the heat exchanger metal matrix, parasitic heat in-leak from surroundings and variation in the fluid/ metal properties are taken care of in the sizing calculation. Numerical studies are carried out to predict the off-design performance of the PFHEs in the refrigeration mode with LN2 pre-cooling. Iterative process cycle calculations are also carried out to obtain the inlet/ exit state points of the heat exchangers.

  4. Use of non-azeotropic binary refrigerants in heat pumps. Die Verwendung von nichtazeotropen Zweistoff-Kaeltemitteln in Waermepumpen

    Energy Technology Data Exchange (ETDEWEB)

    Jakobs, R.M.

    Because of their special mixture properties concerning operating performance, energy and constructional effort, non-azeotropic refrigerant mixtures have got particular advantages for use in heat pumps. Especially in processes with sliding temperatures at heat exchange, mixtures are superior to the straight refrigerants, being able to better adapt to the temperature distribution of the external media at evaporation and condensation, thus reducing the exergy losses. For this purpose heat exchangers are required, however, allowing equilibrium changes of phase, i.e. the vapor and liquid phases have to be intensively mixed. For the theoretical analysis and for evaluation of the experimental results a program library is set up containing materials data, cyclic process and evaluation codes. As a result of the theoretical analysis six combinations of refrigerants were chosen, promising particular advantages if used in heat pumps. For performing operational measurements a test stand was built allowing to make extensive temperature, pressure and output measurements in order to compare straight refrigerants and refrigerant mixtures.

  5. Tuning the heat transfer medium and operating conditions in magnetic refrigeration

    Science.gov (United States)

    Ghahremani, Mohammadreza; Aslani, Amir; Siddique, Abid; Bennett, Lawrence H.; Della Torre, Edward

    2016-07-01

    A new experimental test bed has been designed, built, and tested to evaluate the effect of the system's parameters on a reciprocating Active Magnetic Regenerator (AMR) near room temperature. Bulk gadolinium was used as the refrigerant, silicon oil as the heat transfer medium, and a magnetic field of 1.3 T was cycled. This study focuses on the methodology of single stage AMR operation conditions to get a high temperature span near room temperature. Herein, the main objective is not to report the absolute maximum attainable temperature span seen in an AMR system, but rather to find the system's optimal operating conditions to reach that maximum span. The results of this research show that there is a optimal operating frequency, heat transfer fluid flow rate, flow duration, and displaced volume ratio in any AMR system. By optimizing these parameters in our AMR apparatus the temperature span between the hot and cold ends increased by 24%. The optimized values are system dependent and need to be determined and measured for any AMR system by following the procedures that are introduced in this research. It is expected that such optimization will permit the design of a more efficient magnetic refrigeration system.

  6. Prediction of Heat Transfer Characteristics of Binary Refrigerant Mixtures in a Falling Film Type Plate-fin Evaporator

    Science.gov (United States)

    Yara, Tomoyasu; Koyama, Shigeru

    This paper deals with the characteristics of heat transfer and pressure drop of R 22, R 134a pure refrigerant and R 134a/R123 refrigerant mixtures in a falling film type plate-fin evaporator. The refrigerants have been tested in the ranges of heat flux from 3 to 20 kW/m2 and mass velocity from 50 to 100 kg/m2s. It is clarified that heat transfer characteristics of evaporation in the present experimental range are not affected by shear stress. Taking the fin efficiency into consideration, a correlation equation of heat transfer coefficient is proposed. The characteristic of pressure drop is also proposed by modifying friction factor of Soliman's equation. Furthermore, a prediction model for evaporation of mixtures in a plate fin heat exchanger is developed based on the assumption that the phase equilibrium in a cross-section of the refrigerant path is established. The prediction results are in good agreement with the experimental data.

  7. Heat Transfer Analysis of a Flat-plate Solar Collector Running a Solid Adsorption Refrigerator

    Directory of Open Access Journals (Sweden)

    S. Thiao

    2014-05-01

    Full Text Available Adsorption solar cooling appears to have prospect in the tropical countries. The present study is a theoretical investigation of the performance of a solar adsorption refrigerator using a flat-plate solar collector. The values of glass cover and absorber plate temperatures obtained from numerical solutions of heat balance equations are used to predict the solar coefficient of performance of the solar refrigerator. The simulation technique takes into account the variations of ambient temperature and solar radiation along the day. The effects of optical parameters of the glass cover such as absorption and transmission coefficients on glass cover and absorber plate temperatures and consequently on the coefficient of performance are analyzed. As a result, it is found that the absorber plate temperature is less to the absorption coefficient than the cover glass temperature. Also the thermal radiation exchange has more effect on the cover glass temperature. The higher values of COP are obtained between 11 and 13 h during the morning when the temperatures of the absorber plate and the ambient temperatures increase. Moreover the COP increases with the coefficient of transmission of the glass cover but the main parameter acting on the variations of the COP remains the temperature of the evaporator.

  8. Alternative refrigerants performance in plate heat condenser for air conditioning; Scambiatori compatti per il condizionamento ambientale

    Energy Technology Data Exchange (ETDEWEB)

    Boccardi, G.; Celata, G.P.; Marchesi Donati, F. [ENEA, Rome (Italy). Inst. of Thermal-Fluid Dynamics; Cumo, M. [Rome Univ. La Sapienza, Rome (Italy). Dept. of Nuclear Engineering and Energy Conversion; Gerosa, A. [Rome Univ. Tor Vergata, Rome (Italy). Dept. of Mechanical Engineering; Zorzin, A. [R and D Alfa Laval Artec Spa Vicenza, Vicenza (Italy)

    1999-12-01

    An experimental campaign on plate heat exchangers, used as evaporators and condenser in domestic refrigeration loops is presented in this paper. The research's purpose is to test the influence of some thermal-hydraulic parameters on the global overall heat transfer coefficient. R134a, R407C, R410A, and R22 are the fluids tested under reference thermal conditions. The experimental tests allows one to withdraw conclusions on the substitution effect on the thermal and global efficiency of the plant. Also, a new method for calculating the thermodynamical mixture parameters is applied to the condensation of mixtures R407C and R410A and its benefit evaluated. The refrigerant loop overall performance and the condenser global heat transfer coefficient are the parameters chosen to enlighten the characteristics of the alternative refrigerants (R134a, R407C, and R410A) with respect to the fluid that they are supposed to substitute (R22). [Italian] Scambiatori a piastre compatti impiegati come evaporatori e condensatori nei circuiti frigoriferi, sono l'oggetto della ricerca presentata in questo articolo. L'efficienza termica di tali componenti e' valutata in condizioni di riferimento commerciali. I refrigeranti utilizzati sono tre fluidi proposti per sostituire l'R22, un Hcfc, attualmente il refrigerante piu' utilizzato nel condizionamento ambientale. Una serie di prove condotte con quest'ultimo fluido consente di studiare gli effetti della sostituzione del fluido di progetto sulle prestazioni sia degli scambiatori, sia piu' in generale, dell'intero circuito frigorifero. In particolare sono state studiate le prestazioni di due coppie di evaporatori e condensatori in termini di coefficiente globale di scambio termico e di Cop dell'impianto. Nel presente lavoro e' inoltre presentato e utilizzato un metodo termodinamico per il calcolo della temperatura di saturazione per le miscele zeotropiche in bifase; uno dei refrigeranti

  9. Low Heat-Leak YBCO Leads for Satellite-Borne ADR Magnets Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future satellite missions carrying X-ray spectrometers will be cooled to milliKelvin temperatures by multi-stage Adiabatic Demagnetization Refrigerators (ADR),...

  10. Performance Characteristics of Hybrid Cycle Combined Absorption Heat Transformer and Absorption Refrigerating Machine

    Science.gov (United States)

    Iyoki, Shigeki; Otsuka, Shin-Ichi; Uemura, Tadashi

    In this paper, four kinds of hybrid cycles which combined the single-stage absorption refrigerating machine and four kinds of absorption heat transformers were proposed. It is possible that each of these hybrid cycles gets high temperature and low temperature from one cycle, simultaneously. As basic cycle of absorption heat transformer, the following were chosen: two kinds of single-stage absorption heat transformer and two kinds of two-stage absorption heat transformer. As a working medium-absorbent system, H2O-LiBr system, H2O-LiBr-LiNO3 system, H2O-LiBr-LiNO3-LiCl system, H2O-LiBr-C2H6O2 system and H2O-LiNO3-LiCl system were adopted. Using these five kinds of working medium-absorbent system, the performance characteristics of four kinds of hybrid cycle were simulated. And the performance characteristics of these cycles were compared.

  11. Performance evaluation of heat pump system using R744/R161 mixture refrigerant

    Directory of Open Access Journals (Sweden)

    Zhang Xian-Ping

    2014-01-01

    Full Text Available As an efficient and energy conservation technology, heat pumps working with R22, which are scheduled to be phased out by Montreal Protocol, are widely used in China at present. The global deteriorating ecology environment would accelerate the phase-out time of R22 in developing countries. Therefore, as a matter of urgency, an eco-friendly substitute should be investigated in order to replace R22. Under this context, and with a consideration of the environmental protection, R744/R161 mixture refrigerant is proposed. R744/R161 mixture refrigerant’s condensation pressure is reduced and its flammability and explosivity are suppressed. A thermodynamic model is developed, and under the given working conditions, the performances of subcritical heat pump system using R744/R161 mixture of variable mass fraction are discussed and compared with those of the R22 system. The optimal mass fraction of R744/R161 is given, which corresponds to a maximal heating coefficient of performance. The simulation results show that R744/R161 mixture can work as a competitive alternative to R22 in heat pump system.

  12. Heat pumps: which refrigerant will win?; Welche Kaeltemittel werden sich durchsetzen?

    Energy Technology Data Exchange (ETDEWEB)

    Genath, B.

    2004-07-01

    This article discusses the alternatives available to the refrigeration industry when new regulations concerning the use of hydrochlorofluorocarbons (HCFC) come into force. The alternatives include water, carbon dioxide, iso-butane and propene. Work being done in Europe and America is discussed and examples of installations using these alternative refrigerants are described. Global Warming and the persistence of the refrigerants in the atmosphere are discussed, as is their flammability. Further environmentally-relative characteristics of the various refrigerants are listed.

  13. Fundamentals of Refrigeration; Air Conditioning and Heating Mechanics 1--Appliance Repair 2: 9013.01 and 9025.05.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    Providing the student with an understanding of the basic refrigeration fundamentals, the course introduces the various types of tools and equipment used in this trade. The course consists of 90 clock hours and is organized into six instructional blocks. The student will gain an understanding of trade terminology, heat and temperature, transfer of…

  14. A PERFORMANCE EVALUATION OF A VARIABLE SPEED, MIXED REFRIGERANT HEAT PUMP. SUMMARY. EPA/600/SR-92/053

    Science.gov (United States)

    The performance of an innovative heat pump, equipped with a distillation column to shift the composition of a zeotropic refrigerant mixture, was evaluated. The results of U.S. Department of Energy (DOE) rating tests and seasonal energy calcuations are reported with the main cycl...

  15. A PERFORMANCE EVALUATION OF A VARIABLE SPEED, MIXED REFRIGERANT HEAT PUMP. SUMMARY. EPA/600/SR-92/053

    Science.gov (United States)

    The performance of an innovative heat pump, equipped with a distillation column to shift the composition of a zeotropic refrigerant mixture, was evaluated. The results of U.S. Department of Energy (DOE) rating tests and seasonal energy calcuations are reported with the main cycl...

  16. Heating control strategy in fresh air processor matched with variable refrigerant flow air conditioning system

    Energy Technology Data Exchange (ETDEWEB)

    Tu Qiu, E-mail: tuqiuky@163.co [Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Guangzhou 510640 (China) and Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Science, Guangzhou 510640 (China); Mao Shoubo; Feng Yuhai; Guo Defang [Haier Air-Conditioning Electronic Co. Ltd., Qingdao 266510 (China)

    2011-07-15

    Highlights: {yields} A set of fresh air processor matched with VRF AC has been designed. {yields} The heating control model of variable condensation temperature target has been presented {yields} The control strategy can realize reliable running, high control accuracy and energy-saving. {yields} The control model is universal for fresh air processors with different capacities. -- Abstract: The fresh air processor (FAP), matched with the variable refrigerant flow air conditioning system (VRF AC), has been developed. Two control methods were adopted to control the system running and air outlet temperature, contrastively. The first method is that the running frequency in heating mode is adjusted in terms of the ordinary control method of VRF, i.e., constant condensation temperature. The experiment demonstrates the control method is not feasible. For nominal heating under different static pressure and defrosting under 200 Pa static pressure, the system fluctuates frequently. And for high temperature heating, the air outlet temperature far exceeds the target temperature. Furthermore, the control model of variable condensation temperature target has been presented, and the heat transfer correction factor is introduced into the control model. And the control parameters in the model are determined by experiment. The control model is universal for FAPs with different capacities by identifying and choosing the heat transfer correction factor in the control program. For low temperature heating, the method of switching rotation speed of the motor can be adopted to enhance air outlet temperature to 22 {sup o}C. The control strategy can provide guide for the design and application of FAP.

  17. Cooling, freezing and heating with the air cycle: air as the ultimate green refrigerant

    NARCIS (Netherlands)

    Verschoor, M.J.E.

    2000-01-01

    Due to the recent concern about the damage that CFCs cause to the environment (ozone layer, global warming) and the absence of commonly acceptable alternative refrigerants, the search for alternative refrigeration concepts is going on. Air as refrigerant in the Joule-Brayton cycle (air cycle) is one

  18. A simplified model of heat transfer in heat exchangers and stack plates of thermoacoustic refrigerators

    Science.gov (United States)

    Herman, Cila; Chen, Yuwen

    2006-08-01

    A simplified model of heat transfer was developed to investigate the thermal behavior of heat exchangers and stack plates of thermoacoustic devices. The model took advantage of previous results describing the thermal behavior of the thermoacoustic core and heat transfer in oscillating flow to study the performance of heat exchangers attached to the core. The configuration considered is a flat tube (with a working fluid flowing in the tube) of the thickness of the stack plate attached to both ends of the stack plate. Geometrical and operational parameters as well as thermophysical properties of the heat exchangers, transport fluids in the heat exchangers, stack plate and the thermoacoustic working fluid were organized into dimensionless groups that allowed accounting for their impact on the performance of the heat exchangers. Two types of thermal boundary conditions were considered: constant temperature and constant heat flux along the heat exchanger tubes. Numerical simulations were carried out with the model introduced in the paper. The temperature distributions and heat fluxes near the edge of the stack plate were found to be nonlinear. The influence of system parameters on the thermal performance of the heat exchangers was analyzed.

  19. Thermodynamic optimization of mixed refrigerant Joule- Thomson systems constrained by heat transfer considerations

    Science.gov (United States)

    Hinze, J. F.; Klein, S. A.; Nellis, G. F.

    2015-12-01

    Mixed refrigerant (MR) working fluids can significantly increase the cooling capacity of a Joule-Thomson (JT) cycle. The optimization of MRJT systems has been the subject of substantial research. However, most optimization techniques do not model the recuperator in sufficient detail. For example, the recuperator is usually assumed to have a heat transfer coefficient that does not vary with the mixture. Ongoing work at the University of Wisconsin-Madison has shown that the heat transfer coefficients for two-phase flow are approximately three times greater than for a single phase mixture when the mixture quality is between 15% and 85%. As a result, a system that optimizes a MR without also requiring that the flow be in this quality range may require an extremely large recuperator or not achieve the performance predicted by the model. To ensure optimal performance of the JT cycle, the MR should be selected such that it is entirely two-phase within the recuperator. To determine the optimal MR composition, a parametric study was conducted assuming a thermodynamically ideal cycle. The results of the parametric study are graphically presented on a contour plot in the parameter space consisting of the extremes of the qualities that exist within the recuperator. The contours show constant values of the normalized refrigeration power. This ‘map’ shows the effect of MR composition on the cycle performance and it can be used to select the MR that provides a high cooling load while also constraining the recuperator to be two phase. The predicted best MR composition can be used as a starting point for experimentally determining the best MR.

  20. Improvement of xenon purification system using a combination of a pulse tube refrigerator and a coaxial heat exchanger

    CERN Document Server

    Chen, Wan-Ting; Cussonneau, J -P; Donnard, J; Duval, S; Lemaire, O; Calloch, M Le; Ray, P Le; Mohamad-Hadi, A -F; Morteau, E; Oger, T; Scotto-Lavina, L; Stutzmann, J -S; Thers, D; Briend, P; Haruyama, T; Mihara, S; Tauchi, T

    2012-01-01

    We have developed a compact cryogenic system with a pulse tube refrigerator and a coaxial heat exchanger. This liquefaction-purification system not only saves the cooling power used to reach high gaseous recirculation rate, but also reduces the impurity level with high speed. The heat exchanger operates with an efficiency of 99%, which indicates the possibility for fast xenon gas recirculation in a highpressurized large-scale xenon storage with much less thermal losses.

  1. Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

    OpenAIRE

    Zhenying Zhang; Lili Tian; Yanhua Chen; Lirui Tong

    2014-01-01

    The effect of the internal heat exchanger (IHE) on the performance of the transcritical carbon dioxide refrigeration cycle with an expander is analyzed theoretically on the basis of the first and second laws of thermodynamics. The possible parameters affecting system efficiency such as heat rejection pressure, gas cooler outlet temperature, evaporating temperature, expander isentropic efficiency and IHE effectiveness are investigated. It is found that the IHE addition in the carbon dioxide re...

  2. Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2014-11-01

    Full Text Available The effect of the internal heat exchanger (IHE on the performance of the transcritical carbon dioxide refrigeration cycle with an expander is analyzed theoretically on the basis of the first and second laws of thermodynamics. The possible parameters affecting system efficiency such as heat rejection pressure, gas cooler outlet temperature, evaporating temperature, expander isentropic efficiency and IHE effectiveness are investigated. It is found that the IHE addition in the carbon dioxide refrigeration cycle with an expander increases the specific cooling capacity and compression work, and decreases the optimum heat rejection pressure and the expander output power. An IHE addition does not always improve the system performance in the refrigeration cycle with an expander. The throttle valve cycle with IHE provides a 5.6% to 17% increase in maximum COP compared to that of the basic cycle. For the ideal expander cycle with IHE, the maximum COP is approximately 12.3% to 16.1% lower than the maximum COP of the cycle without IHE. Whether the energy efficiency of the cycle by IHE can be improved depends on the isentropic efficiency level of the expander. The use of IHE is only applicable in the cases of lower expander isentropic efficiencies or higher gas cooler exit temperatures for the refrigeration cycle with an expander from the view of energy efficiency.

  3. Heat transfer and pressure drop performance of smooth and internally finned tubes with oil and refrigerant 22 mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Schlager, L.M. (Indiana-Purdue Univ., Ft. Wayne, IN (US)); Pate, M.B. (Iowa State Univ., Ames, IA (US)); Bergles, A.E. (Rensselaer Polytechnic Inst., Troy, NY (US))

    1989-01-01

    The overall performance of a smooth tube and two augmented tubes is compared by using an enhancement performance ratio, defined as the ratio of heat transfer enhancement to pressure drop increase. The augmented tubes are compared to the smooth tube with pure R-22 and with mixtures of R-22 plus 150-or 300-SUS naphthenic mineral oil. Additionally, the performance of all three tubes with refrigerant-oil mixtures is compared to performance of the same tube with pure refrigerant. Various oil concentrations up to 5% by weight were tested and mass flux was varied from 92,000 to 294,000 lb/h{circle dot}ft{sup 2} (125 to 400 kg/m{sup 2}{circle dot}s). Nominal evaporation conditions were 37{degrees}F(3{degrees}C) with inlet and outlet qualities of 15% and 85%, respectively. The condensation conditions were 105{degrees}F (41{degrees}C) with inlet and outlet qualities of 85% and 15%, respectively. The enhancement performance ratio of the micro-fin tube is consistently higher than that of the low-fin tube with either pure refrigerant or refrigerant-oil mixtures. With pure refrigerant, the enhancement performance ratio of the augmented tubes is generally greater than unity, indicating improved performance relative to a smooth tube.

  4. Exergoeconomic optimization of an irreversible regenerated air refrigerator with constant-temperature heat reservoirs

    Directory of Open Access Journals (Sweden)

    Yi Zhang, Lingeng Chen, Guozhong Chai

    2015-01-01

    Full Text Available Based on the finite time exergoeconomic method, the performance analysis and optimization of an irreversible regenerated air refrigerator cycle are carried out by taking the profit rate as the optimization objective. The profit rate is defined as the difference between the revenue rate of output exergy and the cost rate of input exergy. The analytical expression for profit rate is derived, taking into account several irreversibilities, such as heat resistance, losses due to the pressure drop and the effects of non-isentropic expansion as well as compression. The influences of several parameters such as the temperature ratio of reservoirs, the efficiencies of both compressor and expander, the pressure recovery coefficient and so on are discussed by numerical examples. According to the simulation results, the double-maximum profit rate can be achieved when the pressure ratio and the distributions of heat conductance reach their optimal values respectively. By varying the price ratio, the relationship between the profit rate objective and other objectives can be established and the implementation of profit rate as objective can achieve higher COP compared to the cases using ecological function and cooling load as objectives.

  5. Irreversible three-heat-source refrigerator with heat transfer law of Q{alpha}{delta}(T{sup -1}) and its performance optimization based on ECOP criterion

    Energy Technology Data Exchange (ETDEWEB)

    Ngouateu Wouagfack, Paiguy Armand [University of Dschang, L2MSP, Department of Physics, PO Box 67, Dschang (Cameroon); Tchinda, Rene [University of Dschang, LISIE, University Institute of Technology Fotso Victor, PO Box 134, Bandjoun (Cameroon)

    2011-11-15

    The new thermo-ecological optimization of an absorption system for cooling applications operating between three temperature levels with the linear phenomenological heat transfer law of Q{alpha}{delta}(T{sup -} {sup 1}) has been performed by taking account the losses of heat resistance, internal irreversibility and leakage. The considered objective function is the ecological coefficient of performance (ECOP) and is defined as the cooling load per unit loss rate of availability. The comparative analysis with the ecological optimization criterion (E) defined in the literature and also with the cooling load optimization criterion (R) has been carried out to prove the utility of the new thermo-ecological optimization criterion (ECOP) for three-heat-source refrigerators with linear phenomenological heat transfer law. The results show that the three-heat-source refrigeration cycle working at maximum ECOP conditions has a significant advantage in terms of entropy production rate and coefficient of performance over the maximum E and maximum R conditions. The obtained results may provide a general theoretical tool for the thermo-ecological design of absorption refrigerator. (orig.)

  6. Energy efficient skating rink by heat recovery and CO2 refrigerant; Energiezuinige schaatsbaan door warmteterugwinning en CO2-koudedrager

    Energy Technology Data Exchange (ETDEWEB)

    Mooi, R. [IBK Compac, Houten (Netherlands)

    2009-03-15

    In October 2008 a new indoor skating rink was opened in Enschede, Netherlands. The refrigeration plant for this skating rink was designed, delivered and installed by IBK Compac. CO2 was chosen as the secondary refrigerant; CO2 is easily detectable, sustainable and - above all - very energy efficient, since less pumping energy is required and pipes with a smaller diameter can be used. The waste heat of the refrigeration plant is used for the Zamboni (ice resurfacer), for the central heating system and for the unique floor heating system, which is located under the skating rink. [Dutch] In oktober 2008 werd in Enschede de IJsbaan Twente geopend. Het werd een geheel overdekte schaatsbaan, waarvoor IBK Compac de koude-installatie heeft ontworpen, geleverd en geinstalleerd. Gekozen werd voor CO2 als secundaire koudedrager. CO2 is goed detecteerbaar, duurzaam en vooral zeer energie-efficient doordat er minder pompenergie nodig is en er leidingen met een kleinere diameter kunnen worden gebruikt. De restwarmte van de koelinstallatie wordt o.a. benut voor de dweilmachine (Zamboni), voor het cv-blok en voor het unieke vloerverwarmingssysteem dat onder de ijsbaan ligt.

  7. Numerical optimization of a transcritical CO2/propylene cascaded refrigeration-heat pump system with economizer in HT cycle

    Indian Academy of Sciences (India)

    Alok Manas Dubey; Suresh Kumar; Ghanshyam Das Agrawal

    2015-04-01

    Use of organic refrigerants such as Hydrochlorofluorocarbons and Chlorofluorocarbons have been criticized for their adverse impact on the Earth's protective ozone layer and for their significant global warming potential (GWP). CO2 has been receiving great concern as an alternative refrigerant. Cascade refrigeration systems employing CO2 are used for low temperature applications. Being a low critical temperature fluid CO2 transcritical cascade systems offer low COP for a given application. Parallel compression economization is one of the promising cycle modifications to improve the COP of transcritical CO2 cascaded systems. In this paper, transcritical CO2/propylene cascade system with parallel compression economization in the HT cycle has been analysed for cooling/heating applications. An enhancement in COP of 9% has been predicted. Thermodynamic analysis on R744-R1270 cascade refrigeration system has been performed to determine the optimal value of the various design parameters of the system. The design parameters included are: gas cooler outlet temperature and intermediate temperature in the high temperature circuit and evaporator temperature and temperature difference in the cascade condenser in the low temperature circuit.

  8. Carbon-ammonia pairs for adsorption refrigeration applications: ice making, air conditioning and heat pumping

    Energy Technology Data Exchange (ETDEWEB)

    Tamainot-Telto, Z.; Metcalf, S.J.; Critoph, R.E.; Zhong, Y.; Thorpe, R. [School of Engineering, University of Warwick, Gibbet Hall Road, Coventry CV4 7AL (United Kingdom)

    2009-09-15

    A thermodynamic cycle model is used to select an optimum adsorbent-refrigerant pair in respect of a chosen figure of merit that could be the cooling production (MJ m{sup -3}), the heating production (MJ m{sup -3}) or the coefficient of performance (COP). This model is based mainly on the adsorption equilibrium equations of the adsorbent-refrigerant pair and heat flows. The simulation results of 26 various activated carbon-ammonia pairs for three cycles (single bed, two-bed and infinite number of beds) are presented at typical conditions for ice making, air conditioning and heat pumping applications. The driving temperature varies from 80 C to 200 C. The carbon absorbents investigated are mainly coconut shell and coal based types in multiple forms: monolithic, granular, compacted granular, fibre, compacted fibre, cloth, compacted cloth and powder. Considering a two-bed cycle, the best thermal performances based on power density are obtained with the monolithic carbon KOH-AC, with a driving temperature of 100 C; the cooling production is about 66 MJ m{sup -3} (COP = 0.45) and 151 MJ m{sup -3} (COP = 0.61) for ice making and air conditioning respectively; the heating production is about 236 MJ m{sup -3} (COP = 1.50). (author) [French] Un modele du cycle thermodynamique est utilise pour selectionner le meilleur couple adsorbant-ammoniac sur la base de la production frigorifique (MJ m{sup -3}), la production de chaleur (MJ m{sup -3}) ou bien le coefficient de performance (COP). Ce modele est essentiellement base sur les equations d'etat de l'adsorption (adsorbant-ammoniac). Les resultats de simulation de 26 differents couples charbon actif-ammoniac sont presentes pour des conditions typiques de fabrication de la glace, de climatisation et de pompe a chaleur. La temperature de generation varie de 80 C a 200 C. Les simulations sont effectuees pour trois types de cycle: lit unique, deux-lits et un nombre infini de lits. Les charbons actifs etudies sont

  9. Thermoacoustic engines and refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.

    1996-12-31

    This report is a transcript of a practice lecture given in preparation for a review lecture on the operation of thermoacoustic engines and refrigerators. The author begins by a brief review of the thermodynamic principles underlying the operation of thermoacoustic engines and refrigerators. Remember from thermodynamics class that there are two kinds of heat engines, the heat engine or the prime mover which produces work from heat, and the refrigerator or heat pump that uses work to pump heat. The device operates between two thermal reservoirs at temperatures T{sub hot} and T{sub cold}. In the heat engine, heat flows into the device from the reservoir at T{sub hot}, produces work, and delivers waste heat into the reservoir at T{sub cold}. In the refrigerator, work flows into the device, lifting heat Q{sub cold} from reservoir at T{sub cold} and rejecting waste heat into the reservoir at T{sub hot}.

  10. Thermoacoustic engines and refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.

    1996-12-31

    This report is a transcript of a practice lecture given in preparation for a review lecture on the operation of thermoacoustic engines and refrigerators. The author begins by a brief review of the thermodynamic principles underlying the operation of thermoacoustic engines and refrigerators. Remember from thermodynamics class that there are two kinds of heat engines, the heat engine or the prime mover which produces work from heat, and the refrigerator or heat pump that uses work to pump heat. The device operates between two thermal reservoirs at temperatures T{sub hot} and T{sub cold}. In the heat engine, heat flows into the device from the reservoir at T{sub hot}, produces work, and delivers waste heat into the reservoir at T{sub cold}. In the refrigerator, work flows into the device, lifting heat Q{sub cold} from reservoir at T{sub cold} and rejecting waste heat into the reservoir at T{sub hot}.

  11. Initialization with diabatic heating from satellite-derived rainfall

    Science.gov (United States)

    Ma, Leiming; Chan, Johnny; Davidson, Noel E.; Turk, Joe

    2007-07-01

    In this paper, a new technique is proposed to improve initialization of a tropical cyclone (TC) prediction model using diabatic heating profiles estimated from a combination of both infrared satellite cloud imagery and satellite-derived rainfall. The method is termed Rainfall-defined Diabatic Heating, RDH. To examine the RDH performance, initialization and forecast experiments are made with the Australia Bureau of Meteorology Research Centre (BMRC) Tropical Cyclone — Limited Area Prediction System (TC-LAPS) for the case of TC Chris, which made landfall on the west coast of Australia during 3-6 Feb 2002. RDH is performed in three steps: 1) based on previous observational and numerical studies, reference diabatic heating profiles are firstly classified into three kinds: convective, stratiform or composite types; 2) NRL (Naval Research Laboratory) 3-hourly gridded satellite rainfall estimates are categorized as one of the three types according to the rain rate; 3) within a nudging phase of 24 h, the model-generated heating at each grid point during the integration is replaced by the reference heating profiles on the basis of the satellite-observed cloud top temperature and rainfall type. The results of sensitivity experiments show that RDH has a positive impact on the model initialization of TC Chris. The heating profiles generated by the model within the observed rainfall area show agreement with that of reference heating. That is, maximum heating is located in the lower troposphere for convective rainfall, and in the upper troposphere for stratiform rainfall. In response to the replaced heating and its impact on the TC structure, the model initial condition and forecasts of the track and intensity are improved.

  12. Investigation of Urban Heat Stress from Satellite Atmospheric Profiles

    Science.gov (United States)

    Hu, L.; Brunsell, N. A.

    2014-12-01

    Heat stress is the leading cause of weather-related human mortality in the United States and in many countries world-wide. Heat stress is usually enhanced by the urban heat island effect. Here, we investigate the ability to use remotely sensed atmospheric profiles to detect and monitor heat stress in the urban environment. MODIS atmospheric profiles at 5 km are used to quantify the spatial distribution of heat stress across Chicago during summer periods from 2003-2013. Four heat stress indices are investigated (Discomfort Index (DI), NWS Heat Index (HI), Humidex, and Simplified Wet Bulb Globe Temperature (SWBGT)) from the near-surface temperature and humidity observed at ground sites and retrieved from satellite atmospheric profiles. The heat stress climatology indicates that the urban effects are similar to the heat stress in top 5% hot days and 11 summers during the daytime. There is a lack of relationship between urban fraction and the heat stress on the warmest nights. The nighttime heat stress in the hottest 5% suggests a larger stress compared to the normal conditions during 11 summers. A case study of the heat wave in 2012 is assessed to identify the key pre-heat wave spatial patterns, which may potentially apply to predict future high heat-stress events. In addition, the role of the temporal persistence on the spatial dynamics of the heat wave is also examined. This research illustrates the spatial heat pattern under normal and heat wave conditions, which may help to make public heat health protection strategies. Also, the remotely sensed temperature and humidity information are invaluable to assess urban heat island impact spatially and temporally.

  13. Boiling heat-transfer coefficient variation for R407C inside horizontal tubes of a refrigerating vapour-compression plant's shell-and-tube evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Torrella, Enrique [Department of Applied Thermodynamics, Camino de Vera, 14, Polytechnic University of Valencia, E-46022 Valencia (Spain); Navarro-Esbri, Joaquin; Cabello, Ramon [Department of Technology, Campus de Riu Sec,University Jaume I, E-12071 Castellon (Spain)

    2006-03-01

    The present paper presents experimental results obtained from a refrigerating vapour-compression plant's shell-and-tube (1-2) evaporator working with R407C. Several tests have been carried out to study the influence of the evaporating pressure and the refrigerant's mass flow rate on the refrigerant's boiling heat-transfer coefficient inside horizontal tubes. This work has been performed by analyzing the variations of the evaporator's overall thermal-resistance, computed using the effectiveness-NTU method, considering the influence of pressure drops and glide at the evaporator, and finally transferring the results and conclusions to the boiling heat-transfer coefficient. It has been observed that the variations of the boiling heat-transfer coefficient show a dependence on the evaporating temperature and the refrigerant's mass-flow rate, which has been analyzed in the test range. [Author].

  14. Internal heat exchange in an ejector-compression solar refrigeration system with R142b

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Joge I; Estrada, Claudio A; Best, Roberto [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico); Dorantes Ruben, J [Departamento de Energia, UNAM Azcapotzalco, Mexico, D.F. (Mexico)

    2000-07-01

    One way to use more efficiently the actual energy transfer in the ejector-compression system, is the use of heat exchangers between some of the components. The inclusion of two heat exchangers, preheater and precooler, is considered in a basic ejector-compression refrigeration system with refrigerant 142b. This study accounts for the energy and exergy efficiencies. COP and {epsilon}, according to parameter variations such as ejector efficiency, generation temperature with different superheating, condensation temperature and heat exchangers effectiveness. As known, the most important parameters in ejector-compression system analysis are the entrain-ment ratio U and system efficiencies COP and {epsilon}. The highest system COP and {epsilon}, as the entrainment ratio U, correspond to the highest exchangers effectiveness, highest superheating generator temperatures, highest ejector efficiency and lowest condenser temperature. For the COP and {epsilon} ratios, their maxima correspond to the same independent variables aforementioned for one of the higher superheating generator temperatures. In this case, this result indicates that the exergy efficiency {epsilon} does not contradict the information given by energy efficiency COP. So, to select correctly and optimum design condition, is enough to employ the COP ratio, which maximum value for the data shown corresponds to a superheating generator temperature of about 110 Celsius degrees, that can only be reached by evacuated tubular collectors or CPC solar concentrators. [Spanish] Una forma de usar mas eficientemente la transferencia real de energia en el sistema eyector-compresion es el uso de intercambiadores de calor entre algunos de los componentes. La inclusion de dos intercambiadores de calor precalentador y pre-enfriador se considera en un sistema de refrigeracion eyector-compresion con refrigerante 142b. Este estudio toma en cuenta las eficiencias de energia y exergia, COP y {epsilon}, de acuerdo con las variaciones

  15. To the design of water-admitted heat exchangers for compression-type heat pumps with non-azetropic binary refrigerants. Zur Gestaltung von wasserbeaufschlagten Waermeuebertragern fuer Kompressionswaermepumpen mit nichtazeotropen Zweistoffkaeltemitteln

    Energy Technology Data Exchange (ETDEWEB)

    Heinrich, G. (Technische Univ., Dresden (Germany, F.R.). Sektion Energieumwandlung); Hempel, O. (ILKA Luft- und Kaeltetechnik Dresden GmbH (Germany, F.R.))

    1990-11-01

    The approximation to the 'Lorenz'-process by using of non-azeotropic refrigerant mixtures in heat pumps demands the proper design of evaporator and condenser with priority. Besides the adaption of interior temperature behaviours on exterior mass flows, the limiting of refrigerant pressure losses (specially in the evaporator) is important. Cross-counter flow heat exchangers are better suitable than a counter-flow heat exchanger to guarantee these two conditions. (orig.).

  16. Effect of heat recovery water heater system on the performance of residential split air conditioner using hydrocarbon refrigerant (HCR22)

    Science.gov (United States)

    Aziz, A.; Thalal; Amri, I.; Herisiswanto; Mainil, A. K.

    2017-09-01

    This This paper presents the performance of residential split air conditioner (RSAC) using hydrocarbon refrigerant (HCR22) as the effect on the use of heat recovery water heater system (HRWHS). In this study, RSAC was modified with addition of dummy condenser (trombone coil type) as heat recovery water heater system (HRWHS). This HRWHS is installed between a compressor and a condenser by absorbing a part of condenser waste heat. The results show that RSAC with HRWHS is adequate to generate hot water with the temperature range about 46.58˚C - 48.81˚C when compared to without HRWHS and the use of dummy condenser does not give significant effect to the split air conditioner performance. When the use of HRWHS, the refrigerant charge has increase about 19.05%, the compressor power consumption has slightly increase about 1.42% where cooling capacity almost the same with slightly different about 0.39%. The condenser heat rejection is lower about 2.68% and the COP has slightly increased about 1.05% when compared to without HRWHS. The use of HRWHS provide free hot water, it means there is energy saving for heating water without negative impact to the system performance of RSAC.

  17. Accuracy of surface heat fluxes from observations of operational satellites

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Sugimori, Y.

    with uncertainties for same flux values resulting from climatological ship observations. For net satellite derived heat flux varying from 0 to 300 w/m sup(2) the uncertainties were found to be of the order of 50-90 w/m sup(2). For the same range of flux values...

  18. Compare Energy Use in Variable Refrigerant Flow Heat Pumps Field Demonstration and Computer Model

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Chandan; Raustad, Richard

    2013-07-01

    Variable Refrigerant Flow (VRF) heat pumps are often regarded as energy efficient air-conditioning systems which offer electricity savings as well as reduction in peak electric demand while providing improved individual zone setpoint control. One of the key advantages of VRF systems is minimal duct losses which provide significant reduction in energy use and duct space. However, there is limited data available to show their actual performance in the field. Since VRF systems are increasingly gaining market share in the US, it is highly desirable to have more actual field performance data of these systems. An effort was made in this direction to monitor VRF system performance over an extended period of time in a US national lab test facility. Due to increasing demand by the energy modeling community, an empirical model to simulate VRF systems was implemented in the building simulation program EnergyPlus. This paper presents the comparison of energy consumption as measured in the national lab and as predicted by the program. For increased accuracy in the comparison, a customized weather file was created by using measured outdoor temperature and relative humidity at the test facility. Other inputs to the model included building construction, VRF system model based on lab measured performance, occupancy of the building, lighting/plug loads, and thermostat set-points etc. Infiltration model inputs were adjusted in the beginning to tune the computer model and then subsequent field measurements were compared to the simulation results. Differences between the computer model results and actual field measurements are discussed. The computer generated VRF performance closely resembled the field measurements.

  19. Technical Subtopic 2.1: Modeling Variable Refrigerant Flow Heat Pump and Heat Recovery Equipment in EnergyPlus

    Energy Technology Data Exchange (ETDEWEB)

    Raustad, Richard; Nigusse, Bereket; Domitrovic, Ron

    2013-09-30

    The University of Central Florida/Florida Solar Energy Center, in cooperation with the Electric Power Research Institute and several variable-refrigerant-flow heat pump (VRF HP) manufacturers, provided a detailed computer model for a VRF HP system in the United States Department of Energy's (U.S. DOE) EnergyPlus? building energy simulation tool. Detailed laboratory testing and field demonstrations were performed to measure equipment performance and compare this performance to both the manufacturer's data and that predicted by the use of this new model through computer simulation. The project goal was to investigate the complex interactions of VRF HP systems from an HVAC system perspective, and explore the operational characteristics of this HVAC system type within a laboratory and real world building environment. Detailed laboratory testing of this advanced HVAC system provided invaluable performance information which does not currently exist in the form required for proper analysis and modeling. This information will also be useful for developing and/or supporting test standards for VRF HP systems. Field testing VRF HP systems also provided performance and operational information pertaining to installation, system configuration, and operational controls. Information collected from both laboratory and field tests were then used to create and validate the VRF HP system computer model which, in turn, provides architects, engineers, and building owners the confidence necessary to accurately and reliably perform building energy simulations. This new VRF HP model is available in the current public release version of DOE?s EnergyPlus software and can be used to investigate building energy use in both new and existing building stock. The general laboratory testing did not use the AHRI Standard 1230 test procedure and instead used an approach designed to measure the field installed full-load operating performance. This projects test methodology used the air

  20. Entropy Assessment on Environmental Influence of Condense Heat in Recovery System in Air-Conditioning Refrigerating Machine

    Institute of Scientific and Technical Information of China (English)

    TANG Wen-wu; WANG Han-qing

    2009-01-01

    This paper presented an entropy evaluation method for the influences of condense heat recovery system on the environment.Aiming at the damage of the condense heat to the environment,an entropy of re-source loss and an emission entropy from the condense heat recovery system in the air conditioning refrigerating machine were introduced.For the evaluation of the entropies,we developed a new algorithm for the parameter i-dentifieation.called the composite influence coefficient,based on the Least Squares Support Vector Machine method.By simulation,the numerical experiments shows that the Least Squares Support Vector Machine method is one of the powerful methods for the parameter identification to compute the damage entropy of the condense heat,with the largest training error being-0.025(the relative error being-3.56%),and the biggest test error being 0.015(the relative error being 2.5%).

  1. Waste heat usage in commercial refrigeration systems - Energy analysis of two retail outlets; Abwaermenutzung in der gewerblichen Kaelte. Energetische Analyse von zwei Verkaufsstellen - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Erb, M.; Gutzwiller, S.

    2009-09-15

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of an analysis made on the use of waste heat produced by the refrigeration systems in two retail stores. The results of field measurements made in two installations in Migros and Coop supermarkets are presented. The efficiencies of heat recovery determined for the refrigeration systems are presented and discussed. The electro-thermal amplification factors (ETV) of the systems determined for the two installations are discussed. Basically, the authors are of the opinion that the ETV noted are very good. In both installations, heat recovery is energetically and ecologically very efficient. The factors leading to a high ETV are discussed and recommendations for the planning of such heat-recovery systems are made. An appendix includes schematics of the refrigeration systems in the two stores.

  2. About Solar Refrigeration

    Directory of Open Access Journals (Sweden)

    Laura Coroiu

    2008-05-01

    Full Text Available This paper has the purpose to unfold the results of all researches which proved before that the solar energy constitutes itself as an ideal resource for heating application that necessitate lower temperature,e.g. the heating of a certain space or the preparation ofthe domestic hot water. The refrigeration systems, which are based on the nontoxic refrigerants for the environment, offer a sustained advantage when compared to the other types of the refrigerants. But, whichever might be the case, the use of the energy associated to the operation of the refrigeration system and with the impact that it has upon the environment, as well as the association with its production and distribution, have often a bigger importance than the selection of the refrigerant. In order to minimize the impact which the operation of the refrigeration systems exerts upon the environment, it is recommended that there should be checked all thepossibilities of using a pure source of energy.

  3. 渔船动力余热制冷技术%Refrigeration Technology Utilizing Engine Waste Heat in Fishing Vessels

    Institute of Scientific and Technical Information of China (English)

    陈少杰; 陈光明

    2014-01-01

    Ice and compression refrigeration are normally used to preserve caught fish on fishing vessels.At the same time, waste heat dissipated in hot exhaust gas on fishing vessels is rejected to the atmosphere.Utilizing the vast amount of the waste energy for refrigeration is both economical and energy saving.Three kinds of heat driven refrigeration cycles as adsorption, absorption and ejection are introduced in this paper.Advantages and disadvantages of the three cycles are analyzed based on the working condition of ice making on fishing ves_sels.Emphases have been made on the feasibility of transforming the existing compression refrigeration cycle on fishing vessels by ejection technology.The result shows that 54.5﹪ of fuel for refrigeration system can be saved after combining ejection and compression cycle and the transforming cost can be recovered in 1 year.%渔船通常需要带冰或使用压缩式制冷来满足渔获冷藏保鲜的需要,而渔船发动机尾气中有大量的热能被排放到环境中去,利用渔船发动机尾气余热制冷是一种既经济又节能的好方法。本文介绍了吸附式﹑吸收式和喷射式三种热能驱动的制冷循环,并针对渔船制冰工况对这三种循环在渔船中应用的优缺点进行了分析;重点讨论了使用喷射式制冷技术对渔船现有压缩式制冷系统进行改造的可行性。研究结果表明,将喷射制冷与压缩制冷结合,可减少渔船制冷系统燃料消耗54.5﹪,在1年内即可收回改造成本。

  4. Simultaneous heat and mass transfer of a packed distillation column for ammonia-water absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Sieres, Jaime; Vazquez, Manuel [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales de Vigo, Universidad de Vigo, Campus Lagoas-Marcosende, N circle 9, 36200, Vigo (Spain)

    2002-10-01

    This paper presents a study on the NH{sub 3}-H{sub 2}O distillation process using a packed column with liquid reflux from the condenser in an absorption refrigeration system. A differential mathematical model has been developed on the basis of mass and energy balances and the heat and mass transfer equations. A net molar flux between the liquid and vapour phases has been considered in the mass transfer equation, which obviates the need to assume equimolar counter-diffusion. The model equations have been solved using the finite-difference method. Results obtained for a specific application are shown, including parameter distributions along the column length. The influence of rectifying and stripping lengths, mass and heat transfer coefficients and volumetric heat rejection from the column, on the distillate ammonia concentration has been analysed. (authors)

  5. Non-linear model predictive supervisory controller for building, air handling unit with recuperator and refrigeration system with heat waste recovery

    DEFF Research Database (Denmark)

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

    2016-01-01

    In this paper we examine a supermarket system. In order to grasp the most important dynamics we present a model that includes the single zone building thermal envelope with its heating, cooling and ventilation. Moreover we include heat waste recovery from the refrigeration high pressure side. The...

  6. Effect of Fin Geometry on Condensation Heat Transfer of Refrigerant R134a on Enhanced Finned Tubes

    Science.gov (United States)

    Takahashi, Hiroyuki; Saeki, Chikara; Koyama, Shigeru

    This paper presents the experimental results on the outside condensation heat tral1sfer coefficient of horizontal enhanced filmed tubes. Three different fin geometry types of three-dimensional enhanced finned tubes were tested. A low-fin-tube (LFT) 19 fin-per-inch (fpi) was also tested for reference. Experimental refrigerant used was R134a. The heat tral1sfer coefficient test was carried out at a condensing temperature of 40°C, at a cooling water velocity of 1.5 m/s, and the heat flux of 10 to 110 kW/m2K. The outside condensation heat transfer coefficient of all three dimensional enhanced finned tubes were approximately 1.9 times higher than that of LFTl9fpi at high heat flux range. In low heat flux range, the enhanced finned tube of small circumferential segmentation pitches at the fin tip was shown the highest outside heat transfer coefficient for all tubes tested.

  7. Design and Thermodynamic Analysis of a Steam Ejector Refrigeration/Heat Pump System for Naval Surface Ship Applications

    Directory of Open Access Journals (Sweden)

    Cüneyt Ezgi

    2015-12-01

    Full Text Available Naval surface ships should use thermally driven heating and cooling technologies to continue the Navy’s leadership role in protecting the marine environment. Steam ejector refrigeration (SER or steam ejector heat pump (SEHP systems are thermally driven heating and cooling technologies and seem to be a promising technology to reduce emissions for heating and cooling on board naval surface ships. In this study, design and thermodynamic analysis of a seawater cooled SER and SEHP as an HVAC system for a naval surface ship application are presented and compared with those of a current typical naval ship system case, an H2O-LiBr absorption heat pump and a vapour-compression heat pump. The off-design study estimated the coefficient of performances (COPs were 0.29–0.11 for the cooling mode and 1.29–1.11 for the heating mode, depending on the pressure of the exhaust gas boiler at off-design conditions. In the system operating at the exhaust gas boiler pressure of 0.2 MPa, the optimum area ratio obtained was 23.30.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-15

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

  9. Technical Subtopic 2.1: Modeling Variable Refrigerant Flow Heat Pump and Heat Recovery Equipment in EnergyPlus

    Energy Technology Data Exchange (ETDEWEB)

    Raustad, Richard; Nigusse, Bereket; Domitrovic, Ron

    2013-09-30

    The University of Central Florida/Florida Solar Energy Center, in cooperation with the Electric Power Research Institute and several variable-refrigerant-flow heat pump (VRF HP) manufacturers, provided a detailed computer model for a VRF HP system in the United States Department of Energy's (U.S. DOE) EnergyPlus? building energy simulation tool. Detailed laboratory testing and field demonstrations were performed to measure equipment performance and compare this performance to both the manufacturer's data and that predicted by the use of this new model through computer simulation. The project goal was to investigate the complex interactions of VRF HP systems from an HVAC system perspective, and explore the operational characteristics of this HVAC system type within a laboratory and real world building environment. Detailed laboratory testing of this advanced HVAC system provided invaluable performance information which does not currently exist in the form required for proper analysis and modeling. This information will also be useful for developing and/or supporting test standards for VRF HP systems. Field testing VRF HP systems also provided performance and operational information pertaining to installation, system configuration, and operational controls. Information collected from both laboratory and field tests were then used to create and validate the VRF HP system computer model which, in turn, provides architects, engineers, and building owners the confidence necessary to accurately and reliably perform building energy simulations. This new VRF HP model is available in the current public release version of DOE?s EnergyPlus software and can be used to investigate building energy use in both new and existing building stock. The general laboratory testing did not use the AHRI Standard 1230 test procedure and instead used an approach designed to measure the field installed full-load operating performance. This projects test methodology used the air

  10. Heat and Charge Current Fluctuations and the Time-Dependent Coefficient of Performance for a Nanoscale Refrigerator

    Science.gov (United States)

    Okada, Hiroki; Utsumi, Yasuhiro

    2017-02-01

    We theoretically investigate the coefficient of performance (COP) of a mesoscopic thermoelectric refrigerator realized by using a tunnel junction. We analyze the influence of particle and heat current fluctuations on the COP out of the equilibrium regime. We calculate the average COP by using full counting statistics and find that it depends on the measurement time τ. The deviation from the macroscopic COP value can be expressed with the Skellam distribution at all times. This result enables us to improve the Gaussian approximation valid within the linear response regime, which cannot predict the average COP in the limit of τ → 0. We illustrate the time dependence of the average COP and find that in the short-time regime, the average COP possesses a minimum. In order to confirm the physical consistency far from equilibrium, we propose checking the correlation coefficient between the particle and the heat currents in addition to the positivity of the entropy production rate.

  11. Economic analysis of wind-powered refrigeration cooling/water-heating systems in food processing. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Garling, W.S.; Harper, M.R.; Merchant-Geuder, L.; Welch, M.

    1980-03-01

    Potential applications of wind energy include not only large central turbines that can be utilized by utilities, but also dispersed systems for farms and other applications. The US Departments of Energy (DOE) and Agriculture (USDA) currently are establishing the feasibility of wind energy use in applications where the energy can be used as available, or stored in a simple form. These applications include production of hot water for rural sanitation, heating and cooling of rural structures and products, drying agricultural products, and irrigation. This study, funded by USDA, analyzed the economic feasibility of wind power in refrigeration cooling and water heating systems in food processing plants. Types of plants included were meat and poultry, dairy, fruit and vegetable, and aquaculture.

  12. 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.

  13. Variable conductance heat pipe technology. [research project resulting in heat pipe experiment on OAO-3 satellite

    Science.gov (United States)

    Anderson, W. T.; Edwards, D. K.; Eninger, J. E.; Marcus, B. D.

    1974-01-01

    A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included.

  14. Design and simulation of heat pumps and A/C equipment using pure and mixed refrigerants with MoMo (Modular Modelling)

    Energy Technology Data Exchange (ETDEWEB)

    Bensafi, A. [CETIAT, Centre Technique des Industries Aerauliques et Thermiques, 69 - Villeurbanne (France)

    1999-07-01

    An approach to the steady-state simulation of A/C, heat pumping and refrigerating equipment is presented. Novel features of the proposed model are the strategy and formalism adopted. Individual mathematical models for component design are dynamically linked to enable the simulation of a vapour compression cycle. This paper introduces some of the component modules, which can be used for pure as well as mixed refrigerants. Because numerous models can be used for specific pieces of equipment making up the whole refrigerating/heating unit, the Modular Modeling approach leads to a flexible and evolutive structure. The effects of operating conditions, refrigerant charge, or component geometrical parameters on cycle performance can then be examined. Because actual test data are used to 'calibrate' the component modules, very accurate results are obtained. The proposed model is validated with experimental results. Discrepancies smaller than 5% are obtained on the cooling duty and COP. An air conditioning unit using high pressure refrigerant R410A is optimised to illustrate the use of the model. (authors)

  15. Project BEST Vocational English as a Second Language Curriculum: Communication Skills in Training and Employment in Heating, Refrigeration, and Air Conditioning.

    Science.gov (United States)

    Herman, Barbara; Pankratz, David

    Information is provided on the Vocational English as a Second Language (VESL) component of Oakton Community College's Project BEST (Building Energy Systems Technology), a bilingual vocational training program designed to teach limited English proficient students of Polish or Hispanic origin the basics of heating, refrigeration, and air…

  16. Determination of optimum working conditions R22 and R404A refrigerant mixtures in heat-pumps using Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Comakli, K.; Simsek, F.; Comakli, O.; Sahin, B. [Ataturk University, Mechanical Engineering Department, 25240 Erzurum (Turkey)

    2009-11-15

    In this study, refrigerants R22 and R404A five of their binary mixtures which contain about 0%, 25%, 50%, 75% and 100% mass fractions of R404A were tested. It is investigated experimentally the effects of gas mixture rate, evaporator air inlet temperature (from 24 to 32 C), evaporator air mass flow rate (from 0.58 to 0.74 kg/s), condenser air inlet temperature (from 22 to 34 C) and condenser air mass flow rate (from 0.57 to 0.73 kg/s) on the coefficient of performance (COP) and exergetic efficiency values of vapor compression heat-pump systems. To determine the effect of the chosen parameters on the system and optimum working conditions, an experimental design method suggested by Genichi Taguchi was used. In this study, it was observed that the most effective parameters are found to be the condenser air inlet temperature for COP and exergetic efficiency. (author)

  17. Combined refrigeration / heat pump installation at the St. Jakob Arena in Basle; Kombinierte Kaelte- / Waermepumpen- Verdichter-Anlage in der Eissporthalle St. Jakob ARENA, 4142 Muenchenstein, Basel

    Energy Technology Data Exchange (ETDEWEB)

    Frey, P. [P. Frey and Partner, Beratende Ingenieure und Planer, Wilen bei Wil (Switzerland); Bertozzi, L. [Ingenieurbuero Bertozzi, Ingenieurbuero fuer Haustechnik, Chur (Switzerland)

    2003-07-01

    This intermediate report for the Swiss Federal Office of Energy describes the combined refrigeration and heat-pump unit in use at the new 'St. Jakob Arena' ice-sport-centre near Basle, Switzerland, which includes an indoor ice-rink. The centre has been equipped with an ammonia-based refrigeration system with two reciprocating compressors, which can be run in parallel or as part of a 2-stage-process. The two modes of operation are described. In the 'parallel' operating mode, both compressors are used for cold production only. In the '2-stage' operating mode, one compressor acts as the lower stage for cold production an the second as the upper stage for heat production using the rejected heat from condenser of the first stage as a heat source. Data is presented on the system's performance during the first operational season of the installation.

  18. Research and development of utilization technology of solar thermal system for industrial and other use. Development of system of advanced heat process type (chemical refrigeration and cold storage system using solar heat); Sangyoyo nado solar system jitsuyoka gijutsu kaihatsu. Advanced heat process gata system no kaihatsu (taiyonetsu reito reizo no kaihatsu)

    Energy Technology Data Exchange (ETDEWEB)

    Takita, M. [New Energy and Industrial Technology Development Organization, Tokyo (Japan)

    1994-12-01

    Described herein are the results of the FY1994 research program for chemical refrigeration and cold storage system using solar heat. The study on refrigeration materials are aimed at development of new hydrogen-occluding alloys which show good hydrogenation equilibrium characteristics and reactivity at temperature required for stand-alone refrigeration systems aided by solar heat, and still new hydrogen-occluding alloys operable at refrigeration temperature for lower-temperature systems. For the refrigeration materials capable of producing low-temperature heat of -10{degree}C at a regeneration temperature of 140{degree}C produced by solar heat, a La-Ni-Mn-Al alloy is selected for high-temperature use and a La-Y-Ni-Mn alloy for low-temperature use. The study on technology for refrigeration modules develops high-efficiency heat exchangers for refrigeration and regeneration, compatible with the hydrogen-occluding alloys. It also develops air-and water-cooling techniques for hydrogen-occluding alloys, where air is used as the heat source. The test apparatus is designed, installed and operated, to attain a low temperature of -10{degree}C or lower with a heat source of 140{degree}C and air heat source of 28{degree}C. 7 figs.

  19. Stirling Refrigerator

    Science.gov (United States)

    Kagawa, Noboru

    A Stirling cooler (refrigerator) was proposed in 1862 and the first Stirling cooler was put on market in 1955. Since then, many Stirling coolers have been developed and marketed as cryocoolers. Recently, Stirling cycle machines for heating and cooling at near-ambient temperatures between 173 and 400K, are recognized as promising candidates for alternative system which are more compatible with people and the Earth. The ideal cycles of Stirling cycle machine offer the highest thermal efficiencies and the working fluids do not cause serious environmental problems of ozone depletion and global warming. In this review, the basic thermodynamics of Stirling cycle are briefly described to quantify the attractive cycle performance. The fundamentals to realize actual Stirling coolers and heat pumps are introduced in detail. The current status of the Stirling cycle machine technologies is reviewed. Some machines have almost achieved the target performance. Also, duplex-Stirling-cycle and Vuilleumier-cycle machines and their performance are introduced.

  20. Low Global Warming Potential Refrigerants for Commercial Refrigeration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sharma, Vishaldeep [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Abdelaziz, Omar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Supermarket refrigeration systems account for approximately 50% of supermarket energy use, placing this class of equipment among the highest energy consumers in the commercial building domain. In addition, the commonly used refrigeration system in supermarket applications is the multiplex direct expansion (DX) system, which is prone to refrigerant leaks due to its long lengths of refrigerant piping. This leakage reduces the efficiency of the system and increases the impact of the system on the environment. The high Global Warming Potential (GWP) of the hydrofluorocarbon (HFC) refrigerants commonly used in these systems, coupled with the large refrigerant charge and the high refrigerant leakage rates leads to significant direct emissions of greenhouse gases into the atmosphere. Environmental concerns are driving regulations for the heating, ventilating, air-conditioning and refrigeration (HVAC&R) industry towards lower GWP alternatives to HFC refrigerants. Existing lower GWP refrigerant alternatives include hydrocarbons, such as propane (R-290) and isobutane (R-600a), as well as carbon dioxide (R-744), ammonia (R-717), and R-32. In addition, new lower GWP refrigerant alternatives are currently being developed by refrigerant manufacturers, including hydrofluoro-olefin (HFO) and unsaturated hydrochlorofluorocarbon (HCFO) refrigerants. The selection of an appropriate refrigerant for a given refrigeration application should be based on several factors, including the GWP of the refrigerant, the energy consumption of the refrigeration system over its operating lifetime, and leakage of refrigerant over the system lifetime. For example, focusing on energy efficiency alone may overlook the significant environmental impact of refrigerant leakage; while focusing on GWP alone might result in lower efficiency systems that result in higher indirect impact over the equipment lifetime. Thus, the objective of this Collaborative Research and Development Agreement (CRADA) between

  1. Refrigerant recycling apparatus, method and system

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, J.P.; Gordon, R.F.

    1993-07-13

    A refrigerant recycling apparatus for recovery and purification of refrigerant is described comprising: (a) an input conduit system for connecting a refrigerant source to the refrigerant recycling apparatus; (b) a first disposable filter capable of removing moisture and particulates from the refrigerant, said disposable filter being located such that the filter is easily accessible for service; (c) a primary heat exchanger configured so as to provide heat to the refrigerant thereby causing the refrigerant to be vaporized; (d) a secondary heat exchanger for further heating of the refrigerant to further assist in vaporization of the refrigerant; (e) an expansion valve located prior in line to said primary and secondary heat exchangers for controlling the flow of the refrigerant and reducing the pressure of the refrigerant, thereby allowing the refrigerant to expand to a predominantly gaseous state; (f) a separator for removing oil from the refrigerant; (g) a compressor pump having a vacuum producing inlet and a pressure producing outlet, the pump being a hermetically sealed, lubricated-for-life positive displacement pump; (h) a condenser for cooling the refrigerant; (i) a second disposable filter for removing moisture, acids, and other particulates from the refrigerant passing there through, said disposable filter being located in an area easily accessible for servicing; (j) an interconnecting conduit system for interconnecting the input conduit system, the first and second disposable filters, the heat exchangers, the compressor pump, the condenser, the expansion valve, and the refrigerant source; (k) a moisture indicator located after the second disposable filter, for measuring the degree of moisture present within the refrigerant after the refrigerant has flowed through the second disposable filter.

  2. Enhancement of heat transfer in condensation of refrigerant vapor on horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, O.P.; Khizhnyakov, S.V. (Northwestern Polytechnic Inst. (SU))

    1991-01-01

    This paper reports on the technique for predicting the heat transfer coefficients in film condensation of Freons on horizontal tubes with different fin geometries that has been improved. The suggested technique allows for the spatial orientation of the different parts of the heat transfer area, the capillary contraction of condensate, and its holdup on the bottom zone of the horizontal tube.

  3. Experimental results for hydrocarbon refrigerant vaporization inside brazed plate heat exchangers at high pressure

    DEFF Research Database (Denmark)

    Desideri, Adriano; Ommen, Torben Schmidt; Wronski, Jorrit;

    2016-01-01

    In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low qualitywaste thermal energy from industrial processes has been steadily growing. Micro ORC systems are normally equippedwith brazed plate heat exchangers which allows for efficient heat tra...

  4. Design and fabrication of a 3-D printable counter-low/precipitation heat exchanger for use with a novel off-grid solid state refrigeration system

    Science.gov (United States)

    Ryan, Sean Thomas

    Off-grid refrigeration technologies are currently limited to either vapor-compression cycles driven by photovoltaics or solar thermal absorption cycles. Rebound Technologies has recently developed a novel off-grid refrigeration system called Sunchill(TM) for agricultural applications in humid environments in the developing world. The Sunchill(TM) refrigeration system utilizes the daily high and low temperatures to drive a 24 hour refrigeration cycle. Cooling is provided by the dissolution of an endothermic salt, sodium carbonate decahydrate. Once the salt is solvated and cooling is delivered to freshly harvest crops, the system is "recharged" in a multi-step process that relies on a solar collector, an air-gap membrane unit and a heat exchanger. The heat exchanger, which is the focus of this thesis, is required to remove 36.6 MJ of heat over a twelve hour period in order to "recharge" the system. The heat exchanger is also required to transfer heat from a fresh water stream to a cold brine solution to generate the cold water necessary to submerse and cool harvested crops. To provide a sustainable technology to the target community, the feasibility of fabricating the heat exchanger via the low cost 3-D printing method of fused filament fabrication (FFF) was examined. This thesis presents the design, development, and manufacturing considerations that were performed in support of developing a waterproof, counter-flow, 3-D printable heat exchanger. Initial geometries and performance were modeled by constructing a linear thermal resistance network with truncating temperatures of 30°C (saturated brine temperature) and 18°C (average daily low temperature). The required surface area of the heat exchanger was found to be 20.46 m2 to remove the required 36.6 MJ of heat. Iterative print tests were conducted to arrive at the wall thickness, hexagon shape, and double wall structure of the heat exchanger. A laboratory-scale heat exchanger was fabricated using a Lulzbot Taz 4

  5. Satellite air temperature estimation for monitoring the canopy layer heat island of Milan

    DEFF Research Database (Denmark)

    Pichierri, Manuele; Bonafoni, Stefania; Biondi, Riccardo

    2012-01-01

    2007 and 2010 were processed. Analysis of the canopy layer heat island (CLHI) maps during summer months reveals an average heat island effect of 3–4K during nighttime (with some peaks around 5K) and a weak CLHI intensity during daytime. In addition, the satellite maps reveal a well defined island shape......In this work, satellite maps of the urban heat island of Milan are produced using satellite-based infrared sensor data. For this aim, we developed suitable algorithms employing satellite brightness temperatures for the direct air temperature estimation 2 m above the surface (canopy layer), showing...

  6. Refrigerated display cabinets; Butikskyla

    Energy Technology Data Exchange (ETDEWEB)

    Fahlen, Per

    2000-07-01

    This report summarizes experience from SP research and assignments regarding refrigerated transport and storage of food, mainly in the retail sector. It presents the fundamentals of heat and mass transfer in display cabinets with special focus on indirect systems and secondary refrigerants. Moreover, the report includes a brief account of basic food hygiene and the related regulations. The material has been compiled for educational purposes in the Masters program at Chalmers Technical University.

  7. Use of Disinfectants and Sanitizers in Heating, Ventilation, Air Conditioning, and Refrigeration Systems

    Science.gov (United States)

    This letter is to brings attention several concerns that the Agency has regarding the use of sanitizer and/or disinfectant products, and other types of antimicrobial products, to treat the surfaces of heating, ventilation

  8. Multi-Bed Multi-Stage Adsorption Refrigeration Cycle-Reducing Driving Heat Source Temperature

    Science.gov (United States)

    Alam, K. C. Amanul; Akahira, Akira; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao; Saha, Bidyut Baran; Koyama, Shigeru; Ng, Kim Choon; Chua, Hui Tong

    The study aims at designing a multi-bed multi-stage adsorption chiller that can be driven by waste heat at near ambient temperature. The chiller is designed such a way that it can be switched into different modes depending on the driving heat source temperature. Stage regeneration techniques have been applied to operate the chiller by relatively low temperature heat source. Driving heat source temperature is validated by simulated data and the performances obtained from different modes are compared. In terms of COP (Coefficient of performance),the chiller shows best performance in conventional single-stage mode for driving heat source temperature greater than 60°C, two stage mode for driving source temperature between 42 and 60°C,in three-stage mode for driving source temperature less than 42°C. In terms of cooling capacity, it shows the best performance in single-stage mode for heat source temperature greater than 70°C. The mass recovery process in single-stage mode is also examined. It is seen that the mass recovery process improve cooling capacity significantly, specially for the low regenerating temperature region.

  9. Performance of a fast response miniature Adiabatic Demagnetisation Refrigerator using a single crystal tungsten magnetoresistive heat switch

    Science.gov (United States)

    Bartlett, J.; Hardy, G.; Hepburn, I. D.

    2015-12-01

    The performance of a fast thermal response miniature Adiabatic Demagnetisation Refrigerator (ADR) is presented. The miniature ADR is comprised of a fast thermal response Chromium Potassium Alum (CPA) salt pill, two superconducting magnets and unconventionally, a single crystal tungsten magnetoresistive (MR) heat switch. The development of this ADR is a result of the ongoing development of a continuously operating millikelvin cryocooler (mKCC), which will use only magnetoresistive heat switches. The design and performance of the MR heat switch developed for the mKCC and used in the miniature ADR is presented in this paper; the heat switch has a measured Residual Resistivity Ratio of 32,000 ± 3000 and an estimated switching ratio (on thermal conductivity divided by the off thermal conductivity) of 15,200 at 3.6 K and 38,800 at 0.2 K when using a 3 T magnetic field. The performance of the miniature ADR operating from a 3.6 K bath is presented, demonstrating that a complete cycle (magnetisation, cooling to the bath and demagnetisation) can be accomplished in 82 s. A magnet current step test, conducted when the ADR is cold and fully demagnetised, has shown the thermal response of the ADR to be sub-second. The measured hold times of the ADR with just parasitic heat load are given, ranging from 3 min at 0.2 K with 13.14 μW of parasitics, to 924 min at 3 K with 4.55 μW of parasitics. The cooling power has been measured for operating temperatures in the range 0.25-3 K by applying an additional heat load to the ADR via a heater, in order to reduce the hold time to 3 min (i.e. approximately double the recycle time); the maximum cooling power of the miniature ADR (in addition to parasitic load) when operating at 250 mK is 20 μW, which increases to 45 μW at 300 mK and continues to increase linearly to nearly 1.1 mW at 3 K. To conclude, the predicted performance of a tandem continuous ADR utilising two of the miniature ADRs is presented.

  10. Evaporation of alternative refrigerants to R 22 in technical shell and tube heat exchangers; Verdampfung von Ersatzkaeltemitteln fuer R 22 in technischen Rohrbuendel-Waermeaustauschern

    Energy Technology Data Exchange (ETDEWEB)

    Bonekamp, S. [Henkel KGaA, Duesseldorf (Germany)

    2000-05-01

    The refrigerant mixtures R 404A, R 407C, R 410A and R 507 and the pure fluids R 134a, ammonia, propane and propene are mainly recommended for substituting R 22. This report shows the results of heat transfer calculations for these refrigerants over a wide application range for flooded and for direct expansion evaporation. To determine the best substitute for R 22 the heat transfer areas are compared and a ranking for both types of evaporators is presented. (orig.) [German] Als Ersatz fuer R 22 werden hauptsaechlich die Kaeltemittelgemische R 404A, R 407C, R 410A und R 507 sowie die reinen Stoffe R 134a, Ammoniak, Propan und Propen diskutiert. Diese Arbeit stellt Berechnungsergebnisse fuer die verschiedenen Ersatzkaeltemittel in einem grossen technischen Anwendungsbereich sowohl fuer ueberflutete als auch fuer Einspritz-Verdampfer vor. Der Vergleich der ermittelten Waermeaustauschflaechen liefert fuer beide Verdampfungsarten eine Reihenfolge fuer die Verwendbarkeit als Austauschstoff fuer R 22. (orig.)

  11. EHD enhancement of boiling/condensation, heat transfer of alternate refrigerants. Final Report for 1993-1999

    Energy Technology Data Exchange (ETDEWEB)

    Ohadi, M. M.

    1999-09-01

    The goal was to address the feasibility of frost control by the EHD technique for operating conditions and geometries of significance to refrigeration. The objective of the experimental investigation was to demonstrate by experiment the feasibility of the EHD technique for control of frost on a cold surface under operating conditions of direct significance to refrigeration applications.

  12. Heat recovery system to power an onboard NH{sub 3}-H{sub 2}O absorption refrigeration plant in trawler chiller fishing vessels

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, J.; Vales, A.; Vazquez, M. [Escuela Tecnica Superior de Ingenieros Industriales, Vigo (Spain). Area de Maquinas y Motores Termikcos

    1998-12-01

    This paper is concerned with the design, modelling and parametric analysis of a gas-to-thermal fluid heat recovery system from engine exhausts in a trawler chiller fishing vessel to power an NH{sub 3}-H{sub 2}O absorption refrigeration plant for onboard cooling production. Synthetic oil was used as heat transfer fluid and recirculated. The major components of the system are fluid-to-solution and gas-to-fluid heat exchangers. Both heat exchangers and the complete system have been modelled. Models are implemented in several computer programs. These models have been used to study the influence of geometric design parameters and thermal operating conditions on heat exchangers and system thermal performance. The analysis of the results allowed us to find the optimum thermal operating conditions that minimise total heat transfer area. Optimal design based on real data was performed and the operating function of exhaust gases by-pass control was obtained and is presented. (author)

  13. Energetic evaluation of an internal heat exchanger in a CO{sub 2} transcritical refrigeration plant using experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Torrella, E. [Department of Applied Thermodynamics, Camino de Vera 14, Polytechnic University of Valencia, E-46022 Valencia (Spain); Sanchez, D.; Llopis, R.; Cabello, R. [Department of Mechanical Engineering and Construction, Campus de Riu Sec, Jaume I University, E-12071 Castellon (Spain)

    2011-01-15

    The performance of an Internal Heat Exchanger (IHX) operating in a CO{sub 2} transcritical refrigeration plant is analysed, from an energetic point of view, in this work. The evaluation is based on experimental data by contrasting the performance of the plant working with (44 tests) and without the IHX (46 tests) at the same operating conditions. The experimental evaluation covers three evaporating levels (-5, -10 and -15 C), at two different gas-cooler outlet temperatures each (31, 34 C), for a wide range of gas-cooler operating pressures (74.5-105.9 bar). The thermal effectiveness of the IHX is empirically analysed for the different operating conditions in the first part of the paper. Moreover, the relation of its effectiveness with the operating parameters is presented. The second part is devoted to analyse the modification of the energetic performance of the plant caused by the IHX. The results show a maximum increment on cooling capacity of 12%, an increment of the efficiency of the plant up to 12% and a maximum increase on discharge temperature of 10 C at -15 C of evaporating temperature. (author)

  14. 基于R125工质热泵循环的理论分析%Theoretical Analysis of R125 as Refrigerant of Heat Pump

    Institute of Scientific and Technical Information of China (English)

    黄峻伟; 王华; 王辉涛; 李俊贤; 唐千喻

    2011-01-01

    This thesis has analyzed the cycle process of heat pump, on this basis, the mathematical model of heat pump with regenerator internal heat exchanger is constructed. Theoretical analysis of R125 as refrigerant of heat pump. After systematical calculating and analyzing the cycle performance of the heat pump charged with R125 and several types under standard operating condition and variable operating conditions, The results show that the coefficient of performance with R125 is better than R22 under standard, thus R125 can be regarded as a promising alternative of refrigerant heat pump.%通过对热泵循环流程的分析,构建了带有回热器热泵的数理模型.理论分析了以R125为工质的热泵系统,并对R125及几种热泵工质在标准工况和变工况下的循环性能进行了系统的理论计算及分析.结果表明,在标准工况下,R125制热系数优于R22,是极有潜力的热泵替代工质.

  15. High Performance Cascading Adsorption Refrigeration Cycle with Internal Heat Recovery Driven by a Low Grade Heat Source Temperature

    Directory of Open Access Journals (Sweden)

    Yuki Ueda

    2009-11-01

    Full Text Available This paper presents the performance of an advanced cascading adsorption cycle that utilizes a driven heat source temperature between 90–130 ºC. The cycle consists of four beds that contain silica gel as an adsorber fill. Two of the beds work in a single stage cycle that is driven by an external heat source, while the other two beds work in a mass recovery cycle that is driven by waste heat of sensible and adsorption heat of the high temperature cycle. The performances, in terms of the coefficient of performance (COP and the specific cooling power (SCP, are compared with conventional cascading-without-mass-recovery and single-stage cycles. The paper also presents the effect of the adsorbent mass on performance. The results show that the proposed cycle with mass recovery produces as high of a COP as the COP that is produced by the conventional cascading cycle. However, it produces a lower SCP than that of the single-stage cycle.

  16. Geothermal Heat Flux Underneath Ice Sheets Estimated From Magnetic Satellite Data

    DEFF Research Database (Denmark)

    Fox Maule, Cathrine; Purucker, M.E.; Olsen, Nils

    The geothermal heat flux is an important factor in the dynamics of ice sheets, and it is one of the important parameters in the thermal budgets of subglacial lakes. We have used satellite magnetic data to estimate the geothermal heat flux underneath the ice sheets in Antarctica and Greenland....... By using satellite data, we are able to make heat flux maps covering the entire Antarctic continent and all of Greenland. We find that the heat flux varies from less than 50 to more than 150~mW/m2 underneath the ice sheets. To validate our results, we have compared our heat flux estimate with geologic...

  17. Support of NASA ADR/ Cross-Enterprise NRA Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling from 10K to 50mK, Development of a Heat Switch

    Science.gov (United States)

    Richards, Paul L.

    2005-01-01

    Mechanical heat switches are used in conjunction with sorption refrigerators, adiabatic demagnetization refrigerators and for other cryogenic tasks including the pre-cooling cryogenic systems. They use a mechanical actuator which closes Au plated Cu jaws on an Au plated Cu bar. The thermal conductance in the closed position is essentially independent of the area of the jaws and proportional to the force applied. It varies linearly with T. It is approximately 10mW/K for 200 N at 1.5K. In some applications, the heat switch can be driven from outside the cryostat by a rotating rod and a screw. Such heat switches are available commercially from several sources. In other applications, including systems for space, it is desirable to drive the switch using a cold linear motor, or solenoid. Superconducting windings are used at temperatures s 4.2K to minimize power dissipation, but are not appropriate for pre-cooling a system at higher temperatures. This project was intended to improve the design of solenoid activated mechanical heat switches and to provide such switches as required to support the development of Advanced Adiabatic Demagnetization Refrigerators for Continuous Cooling from 10 K to 50 mK at GSFC. By the time funding began in 5/1/01, the immediate need for mechanical heat switches at GSFC had subsided but, at the same time, the opportunity had arisen to improve the design of mechanical heat switching by incorporating a "latching solenoid". In this device, the solenoid current is required only for changing the state of the switch and not during the whole time that the switch is closed.

  18. Refrigerant Selection for Cascade Water-to-water Heat Pump%复叠式水水热泵的制冷剂筛选

    Institute of Scientific and Technical Information of China (English)

    赵海波; 杨昭

    2012-01-01

    结合我国现行制冷剂标准,按照环境相容性、安全性、热工循环性能原则进行了高温复叠式热泵循环的制冷剂筛选,对不同制冷剂组合进行了计算和分析.结果表明,高低温侧制冷剂可采用R245fa/R134a、R245fa/R420A、R245fa/R413A、R245ca/R420A等组合.若进一步考虑制冷剂获得的容易程度、经济性等因素时,可选择R245fa/R134a组合.%Based on China National Standard-Number Designation and Safety Classification of Refrigerants, refrigerant for the cascade water-to-water heat pump were selected according to principles of environmental-friendly, safety and thermodynamic cycle performances. Different refrigerant combinations for high- and low-temperature cycles in the cascade heat pump were calculated and compared. Results show that combinations of R245fa/R134a, R245fa/R420A, R245fa/R413A, R245ca/R420A are better for the cascade heat pump. It also shows that, considering easy access and economy of refrigerants, R245fa/R134a combination will be a better choice.

  19. 混合制冷工质核态沸腾的传热研究%Heat transfer in nucleate pool boiling of binary and ternary refrigerant mixtures

    Institute of Scientific and Technical Information of China (English)

    赵耀华; 刁彦华; 鹤田隆治; 西川日出男

    2004-01-01

    Heat transfer coefficients in nucleate pool boiling were measured on a horizontal copper surface for refrigerants,HFC-134a,HFC-32,and HFC-125,their binary and ternary mixtures under saturated conditions at 0.9MPa.Compared to pure components,both binary and ternary mixtures showed lower heat transfer coefficients.This deterioration was more pronounced as heat flux was increased.Experimental data were compared with some empirical and semi-empirical correlations available in literature.For binary mixture,the accuracy of the correlations varied considerably with mixtures and the heat flux.Experimental data for HFC-32/134a/125 were also compared with available correlated equation obtained by Thome.For ternary mixture,the boiling range of binary mixture composed by the pure fluids with the lowest and the medium boiling points,and their concentration difference had important effects on boiling heat transfer coefficients.

  20. Condensation Heat-Transfer Measurements of Refrigerants on Externally Enhanced Tubes.

    Science.gov (United States)

    1987-06-01

    fins (m 2) as Coefficient used in eqn. 5.6 At Area of smooth tube (same as Ao) (m 2) cb Fraction of tube surface flooded C, Sieder -Tate-type...modified Wilson plot method was used to process all data. The Sieder -Tate-type equation (eqn. 4.6)- was used for the inside heat-transfer coefficient. A...Flux 2.535E+04 (W/m𔃼) Tube-metal thermal conduc. 385.0 (W/m.K) Sieder -Tate constant 0.0280 UNCERTAINTY ANALYSIS: VARIABLE PERCENT UNCERTAINTY Mass

  1. Determination of a Vapor Compression Refrigeration System Refrigerant Charge

    Institute of Scientific and Technical Information of China (English)

    YangChun-Xin; DangChao-Bin

    1995-01-01

    A physical model is established in this paper to describe the heat transfer and two phase flow of a refrigerant in the evaporator and condenser of a vapor compression refrigeration system.The model in then used to determine the refrigerant charge in vapor compression units.The model is used for a sensitivity analysis to determine the effect that varing design parameters on the refrigerant charge,The model is also used to evaluate the effect of refrigerant charge and the thermal physical properties on the refrigeration cycle,The predicted value of the refigerant charge and experimental data agree well The model and the method presented in this paper could be used to design vapour compression units such as domestic refrigeratirs and air conditioners.

  2. Energy saving in heat exchangers of industrial refrigeration systems; Ahorro de energia en intercambiadores de calor en los sistemas de refrigeracion industrial

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, A.; Romero Paredes, Hernando; Ambriz, Juan Jose [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D. F. (Mexico)

    1994-12-31

    This paper presents the energy losses of the heat exchangers utilized in industrial refrigeration systems . The effects of the different scaling products on the heat transfer rates are presented and the energy not transferred because of them is evaluated. A simplified method for the evaluation is developed and applied to the evaporators and condensers more frequently employed in the industrial refrigeration systems. The internal and external heat transfer coefficients are evaluated in different types of heat exchangers. The energy losses as a function of the scale thickness on the heat exchanger is shown. [Espanol] El trabajo presenta las perdidas energeticas que se tienen en los intercambiadores de calor usados en los sistemas de refrigeracion industrial. Se presentan los efectos que tienen los diferentes incrustantes en las tasas de transferencia de calor y se evalua la energia que no se transfiere causada por aquellos. Se desarrolla un metodo simplificado de evaluacion y se aplica a los evaporadores y condensadores mas comunes empleados en los sistemas de refrigeracion industrial. Se evaluan los coeficientes internos y externos en diferentes tipos de intercambiadores. Se muestran las perdidas energeticas en funcion del espesor del incrustante en la pared del intercambiador.

  3. Cycling Joule Thomson refrigerator

    Science.gov (United States)

    Tward, E.

    1983-01-01

    A symmetrical adsorption pump/compressor system having a pair of mirror image legs and a Joule Thomson expander, or valve, interposed between the legs thereof for providing a, efficient refrigeration cycle is described. The system further includes a plurality of gas operational heat switches adapted selectively to transfer heat from a thermal load and to transfer or discharge heat through a heat projector, such as a radiator or the like. The heat switches comprise heat pressurizable chambers adapted for alternate pressurization in response to adsorption and desorption of a pressurizing gas confined therein.

  4. Novel method using Dubinin-Astakhov theory in sorption reactor design for refrigeration and heat pump applications

    OpenAIRE

    Tamainot-Telto, Zacharie

    2016-01-01

    This paper presents new methodology that is based on a single given adsorbent-refrigerant pair characteristic (such as activated carbon 208C) leading to the characterization of the same adsorbent (activated carbon 208C) with various refrigerants such as Water, Methanol, Ethanol, R723 (azeotropic mixture of 60% Ammonia and 40% Dimethyl Ether), Dimethyl Ether (DME) and Carbon Dioxide (R744). Overall, the results obtained with both Methanol and Carbon Dioxide (R744) show that the new method pred...

  5. Malone refrigeration

    Science.gov (United States)

    Swift, G. W.

    Malone refrigeration is the use of a liquid near its critical point, without evaporation, as the working fluid in a refrigeration cycle such as the Stirling cycle. We discuss relevant properties of appropriate liquids, and we describe two Malone refrigerators. The first, which was completed several years ago, established the basic principles of use for liquids in such cycles. The second, now under construction, is a linear, free-piston machine.

  6. Survival of Campylobacter spp. in poultry meat preparations subjected to freezing, refrigeration, minor salt concentration, and heat treatment.

    Science.gov (United States)

    Sampers, Imca; Habib, Ihab; De Zutter, Lieven; Dumoulin, Ann; Uyttendaele, Mieke

    2010-02-28

    The survival of Campylobacter spp. under defined conditions of freezing (-22 degrees C) was studied in naturally contaminated chicken skin and minced chicken meat. A decline of approximately one log(10) cfu/g was observed after 1 day of freezing. No further significant reduction was achieved by prolonged storage in the freezer, although a tendency for further gradual reduction of the numbers of Campylobacter spp. present was noted. Campylobacter spp. could still be detected qualitatively (per 0.1g) after 84 days. In a second part of this study, the survival of Campylobacter spp. in a typical minced meat preparation (minced meat supplemented with 1.5% salt (NaCl)) stored at refrigeration (4 degrees C) or frozen (-22 degrees C) was studied. No significant reduction of the pathogen was observed if the minced chicken meat was kept at 4 degrees C for 14 days, opposite to approximately one log(10) cfu/g reduction after 1 day when the minced meat preparation was stored in the freezer (-22 degrees C) for 14 days. The latter reduction is imputed to the effect of freezing as mentioned above and not due to the supplementation of NaCl to minced meat or the combination of NaCl and freezing, because similar reductions of Campylobacter spp. were noticed when minced meat (without addition of NaCl) was frozen. Finally, in a third part of the study, the survival of Campylobacter spp. subjected to a heat treatment, conform to consumer-based pan-frying, in inoculated (4.5+/-0.2 cfu/g) as well as naturally contaminated chicken burgers (2.1+/-0.1 cfu/g) was studied. The Campylobacter spp. numbers declined after 2 min (internal temperature reached circa 38 degrees C), where after 4 min (internal temperature reached circa 57.5 degrees C) they dropped below detectable levels (<10 cfu/g).

  7. Experimental validation of a new sorption refrigerator heated by natural gas; Validacao experimental de um refigerador de sorcao aquecido por gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Maria E. Vieira da; Medeiros, Marcelo R.Q. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Schwarzer, Klemens [Universidade de Ciencias Aplicadas de Aachen (Germany); Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    This article presents the experimental results that validate the operation of a new refrigerator in sorption cycle that uses natural gas as its heat source. The project was financed by the RedeGasEnergia of the Petroleo Brasileiro Company - PETROBRAS and by Brazilian agency Agencia Brasileira Financiadora de Estudos e Projetos - FINEP. The refrigeration cycle has two phases: heating/desorption and cooling/adsorption. The materials used were the zeolite 13X and water. The system components, designed for this project, were: two adsorbers, two burners, one condenser and one evaporator. In the heating phase, the burners were turned on to heat up the adsorbers. The adsorbate was released in the vapor phase e flew to the condenser. After its condensation, the liquid moved by the action of gravity to the evaporator. When the burners were turned off, the adsorbers started to cool down due to natural convection and radiation to the ambient. With the decrease of temperature in the adsorbers, the adsorption process began and temperatures below 0 deg C (ice making) were measured in the evaporator. The equipment showed good thermal performance and temperatures near -4 deg C were measured in the evaporator. To produce 5 kg of ice, 0,123 kg of natural gas was used. (author)

  8. Elastic thickness and heat flux estimates for the uranian satellite Ariel

    Science.gov (United States)

    Peterson, G.; Nimmo, F.; Schenk, P.

    2015-04-01

    The surface of Ariel, an icy satellite orbiting Uranus, shows extensional tectonic features suggesting an episode of endogenic heating in the satellite's past. Using topography derived from stereo-photoclinometry, we identified flexural uplift at a rift zone suggesting elastic thickness values in the range 3.8-4.4 km. We estimate the temperature at the base of the lithosphere to be in the range 99-146 K, depending on the strain rate assumed, with corresponding heat fluxes of 28-92 mW/m2. Neither tidal heating, assuming Ariel's current eccentricity, nor radiogenic heat production from the silicate core are enough to cause the inferred heat fluxes. None of three proposed ancient mean-motion resonances produce equilibrium tidal heating values in excess of 4.3 mW/m2. Thus, the origin of the inferred high heat fluxes is currently mysterious.

  9. 低GWP制冷剂在住宅热泵系统中的性能%The Performance of Low GWP Refrigerants in a Residential Heat Pump System

    Institute of Scientific and Technical Information of China (English)

    周子成

    2015-01-01

    R410A是当前住宅热泵系统中的主要制冷剂之一。它的臭氧消耗潜能值为零,但是其全球气候变暖潜能值高达2088.找寻替代R410A的低GWP制冷剂已成为制冷空调业的一个重要任务。本文综述直接充灌试验方法和已取得的部分成果,%R410A is one of the main refrigerants used today for residential air conditioning and heat pump systems. It has zero ozone depletion potential but its global warming potential is high to 2088. Looking for new low GWP refriger-ants alternatives to replace R410A has become one of the most important goals of refrigeration and air conditioning in-dustry. In this paper,the drop-in test method and some results that have been achieved so far are summarized.

  10. Short-Cycle Adsorption Refrigerator

    Science.gov (United States)

    Chan, C. K.

    1988-01-01

    Modular adsorption/Joule-Thomson-effect refrigerator offers fast regeneration; adsorption/desorption cycle time expected to be 1 minute. Pressurized hydrogen generated by bank of compressor modules during heating phase passes through system of check valves and expands in Joule-Thomson junction as it enters refrigeration chamber. Hydrogen absorbs heat from load before it is sucked out by another bank of compressor modules in cooling phase.

  11. Evaluation of specific heat peak and half-width for magnetic regenerative materials (RCuO) of 4K refrigerator; 4K reitoki yo jisei chikureizai kagobutsu (RCuO) no hinetsu piku to hannehaba no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, S.; Nakane, H.; Hashimoto, T.; Sakagami, H. [Kogakuin Univ., Tokyo (Japan); Okamura, M. [Toshiba Corp., Tokyo (Japan); Numazawa, T. [National Research Inst. for Metals, Tokyo (Japan)

    1999-11-10

    For material selection in the multistory structure regeneration vessel of the GM refrigerating machine, we have the meaning in which specific heat peak value and half-value width of material are important. It announced specific heat peak-half-value width characteristics of rare earth magnetic material RSb. For the purpose of searching new regeneration material it improves a refrigerating capacity of refrigerating machine for 4K, it evaluated R{sub 2}BaCuO{sub 5} mainly noticed as superconducting material and R{sub 2}Cu{sub 2}O{sub 5} specific heat peak and half-value width as a magnetic material, which covered the specific heat characteristics of helium in low temperature. (NEDO)

  12. 线性唯象传热时不可逆卡诺制冷机的生态学最优性能%Ecological Optimization for Irreversible Carnot Refrigerator with another liner heat transfer law

    Institute of Scientific and Technical Information of China (English)

    朱小芹; 眭永兴

    2014-01-01

    以反映制冷机制冷率与熵产率之间最佳折衷的“生态学”准则为目标,综合考虑热阻、热漏及工质内不可逆性,导出了时不可逆制冷机的生态学最优性能,由数值算例对不同损失情况下制冷机的性能变化规律进行了比较分析,本文结果对实际制冷机的设计工作具有一定的理论指导意义。%Considering comprehensively the effect of heat-resistance,heat leak and internal irreversibility on the performance of Carnot refrigerator,the optimal ecological performance of Carnot refrigerator with another liner heat transfer law is derived by taking an ecological optimization criterion as the objective,which consists of maximizing a function representing the best compromise between the refrigeration rate and entropy produc-tion rate of refrigerator.Detailed numerical examples show the effect of different losses on the optimal per-formance of the irreversible refrigerator.The results can provide some theoretical guidance for the designs of practical refrigerator.

  13. Study on Jet-Compression Hybrid Refrigeration Cycle Driven by Heat and Power%热-电驱动喷射压缩复合制冷循环特性研究

    Institute of Scientific and Technical Information of China (English)

    王林; 谈莹莹; 梁坤峰; 安方涛; 陈宁

    2014-01-01

    Autocascade refrigeration can achieve lower refrigeration temperature easily,but it totally consumes high grade energy and its COP is low.Jet refrigeration can achieve the refrigeration effect by utilizing low grade heat sources.However,its refrigeration temperature is high.In order to utilize low grade heat to the domain of cryogenic freezing,jet/compression hybrid refrigeration cycle with mixed refrigerants driven by low grade heat and power was presented.The new cycle contributes to improving the efficiency of refrigeration significantly and achieving lower refrigeration temperature.On a basis of its mathematical model,the influences of compression ratio of the ejector and compressor on mechanical and thermal coefficient of performance(COPme/COPth) were analyzed.The results indicate that refrigeration efficiency of the hybrid refrigeration cycle is much higher than that of the traditional autocascade refrigeration cycle.%自复叠制冷循环具有获得制冷温度低优点,但其完全消耗的是高品位电能或机械能;喷射制冷具有利用低品位低温热源(60~100℃)制取冷量、且制冷温度较高时制冷效率高等优点,但难以获得较低制冷温度.因此,为了实现低品位热在低温冷冻领域高效利用并节省高品位电能,本文提出一种由低品位低温热源与电能联合驱动的混合工质喷射/压缩复合制冷循环.建立组成新循环各部件热力学数学模型,分析喷射器压缩比和压缩机压缩比对复合式制冷循环的热性能系数和机械性能系数影响,并与传统的自复叠制冷循环特性进行比较分析.研究表明,低品位热源与电能联合驱动喷射/压缩复合制冷循环较传统自复叠制冷循环可显著提高制冷效率并获得更低制冷温度.

  14. Experimental study of no-frost refrigerator. Part 1: heat transfer through the walls; Estudo experimental de um refrigerador no-frost. Parte 1: transferencia de calor atraves das paredes

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Joaquim Manoel [Escola Tecnica Federal de Santa Catarina, Sao Jose, SC (Brazil)]. E-mail: joaquim@nrva.ufsc.br; Melo, Claudio; Vieira, Luis Antonio Torquato [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica

    2000-07-01

    This paper approaches the heat transfer in permanent regimen trough the walls of a no-frost refrigerator with two compartments with forced internal ventilation. The presented methodology allows the determination of thermal resistances of the walls externally. Also, the heating effect due to the compressor, the condenser and the air distribution between the compartments are investigated.

  15. Refrigeration a history

    CERN Document Server

    Gantz, Carroll

    2015-01-01

    For thousands of years, humans coped with heat by harvesting and storing natural ice and devising natural cooling systems that utilized ventilation and evaporation. By the mid 1800s, people began developing huge refrigeration machines to manufacture ice. By the early 1900s, engineers developed electric domestic refrigerators, which by 1927 were affordable convenient household appliances. By then, an increasingly sophisticated public demanded more modern-looking appliances than engineers could produce, and a new breed of designers entered the manufacturing world to provide them. During the Depr

  16. Accelerated life tests of specimen heat pipe from Communication Technology Satellite (CTS) project

    Science.gov (United States)

    Tower, L. K.; Kaufman, W. B.

    1977-01-01

    A gas-loaded variable conductance heat pipe of stainless steel with methanol working fluid identical to one now on the CTS satellite was life tested in the laboratory at accelerated conditions for 14 200 hours, equivalent to about 70 000 hours at flight conditions. The noncondensible gas inventory increased about 20 percent over the original charge. The observed gas increase is estimated to increase operating temperature by about 2.2 C, insufficient to harm the electronic gear cooled by the heat pipes in the satellite. Tests of maximum heat input against evaporator elevation agree well with the manufacturer's predictions.

  17. A review of pulse tube refrigeration

    Science.gov (United States)

    Radebaugh, Ray

    This paper reviews the development of the three types of pulse tube refrigerators: basic, resonant, and orifice types. The principles of operation are given. It is shown that the pulse tube refrigerator is a variation of the Stirling-cycle refrigerator, where the moving displacer is substituted by a heat transfer mechanism or by an orifice to bring about the proper phase shifts between pressure and mass flow rate. A harmonic analysis with phasors is described which gives reasonable results for the refrigeration power, yet is simple enough to make clear the processes which give rise to the refrigeration. The efficiency and refrigeration power are compared with those of other refrigeration cycles. A brief review is given of the research being done at various laboratories on both one- and two-stage pulse tubes. A preliminary assessment of the role of pulse tube refrigerators is discussed.

  18. 制冷剂流量控制法在风冷热泵除霜中的应用%Application of Refrigerant Flux Control Method in Air-cooled Heat Pump Defrosting

    Institute of Scientific and Technical Information of China (English)

    苏顺玉; 田甜; 陈俭

    2011-01-01

    Based on the difference of refrigerant flux between refrigeration operating condition and heating operating condition in a heat-pump air-conditioning system, the refrigerant flux in the heat-pump air-conditioning system was controlled by refrigerant flux control method. And the combined method with refrigerant flux control and hot gas bypass defrosting was applied in heat-pump defrosting. The results show that the heat-pump air-conditioning cycling system with refrigerant flux control can be used to restrain or retard frosting in the surface of outdoor heat-exchanger while this system works in order. When the surface of outdoor heat-exchanger was already covered with frost, this system could be used to accelerate defrosting or shorten defrosting time.%根据热泵空调系统中制冷工况和制热工况时制冷剂流量的差别,采用制冷剂流量控制法对热泵空调系统中的制冷剂流量进行控制,并将制冷剂流量控制法与热气旁通法除霜相结合应用于热泵除霜过程中。结果表明,在控制制冷剂流量的热泵空调系统中,系统正常运行时,该循环系统能抑制或减缓室外换热器表面的结霜;当室外换热器表面结霜时,则可加速除霜,缩短除霜时间。

  19. Satellite Ocean Heat Content Suite from 2015-07-01 to 2015-07-31 (NCEI Accession 0139408)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  20. Satellite Ocean Heat Content Suite from 2015-10-01 to 2015-10-31 (NCEI Accession 0139415)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  1. Satellite Ocean Heat Content Suite from 2013-05-01 to 2013-05-31 (NCEI Accession 0139509)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  2. Satellite Ocean Heat Content Suite from 2014-01-01 to 2014-01-31 (NCEI Accession 0139519)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  3. Satellite Ocean Heat Content Suite from 2014-09-01 to 2014-09-30 (NCEI Accession 0139314)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  4. Satellite Ocean Heat Content Suite from 2013-10-01 to 2013-10-31 (NCEI Accession 0139513)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  5. Satellite Ocean Heat Content Suite from 2013-07-01 to 2013-07-31 (NCEI Accession 0139511)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  6. Satellite Ocean Heat Content Suite from 2016-02-01 to 2016-02-29 (NCEI Accession 0144930)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  7. Satellite Ocean Heat Content Suite from 2013-12-01 to 2013-12-31 (NCEI Accession 0139518)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  8. Satellite Ocean Heat Content Suite from 2014-07-01 to 2014-07-31 (NCEI Accession 0139262)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  9. Satellite Ocean Heat Content Suite from 2016-08-01 to 2016-08-31 (NCEI Accession 0156473)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  10. Satellite Ocean Heat Content Suite from 2016-01-01 to 2016-01-31 (NCEI Accession 0141305)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  11. Satellite Ocean Heat Content Suite from 2013-02-01 to 2013-02-28 (NCEI Accession 0139506)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  12. Satellite Ocean Heat Content Suite from 2015-11-01 to 2015-11-30 (NCEI Accession 0139416)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  13. Satellite Ocean Heat Content Suite from 2013-01-01 to 2013-01-31 (NCEI Accession 0139505)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  14. Satellite Ocean Heat Content Suite from 2016-04-01 to 2016-04-30 (NCEI Accession 0149717)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  15. Satellite Ocean Heat Content Suite from 2012-09-01 to 2012-09-30 (NCEI Accession 0139501)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  16. Satellite Ocean Heat Content Suite from 2014-10-01 to 2014-10-31 (NCEI Accession 0139388)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  17. Satellite Ocean Heat Content Suite from 2014-03-01 to 2014-03-31 (NCEI Accession 0139520)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  18. Satellite Ocean Heat Content Suite from 2016-06-01 to 2016-06-30 (NCEI Accession 0155212)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  19. Satellite Ocean Heat Content Suite from 2012-12-01 to 2012-12-30 (NCEI Accession 0139504)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  20. Satellite Ocean Heat Content Suite from 2014-12-01 to 2014-12-31 (NCEI Accession 0139390)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  1. Satellite Ocean Heat Content Suite from 2015-03-01 to 2015-03-31 (NCEI Accession 0139404)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  2. Satellite Ocean Heat Content Suite from 2014-05-01 to 2014-05-31 (NCEI Accession 0139522)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  3. Satellite Ocean Heat Content Suite from 2015-06-01 to 2015-06-30 (NCEI Accession 0139407)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  4. Satellite Ocean Heat Content Suite from 2015-12-01 to 2015-12-31 (NCEI Accession 0140097)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  5. Satellite Ocean Heat Content Suite from 2013-08-01 to 2013-08-31 (NCEI Accession 0139512)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  6. Satellite Ocean Heat Content Suite from 2012-11-01 to 2012-11-30 (NCEI Accession 0139503)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  7. Satellite Ocean Heat Content Suite from 2013-04-01 to 2013-04-30 (NCEI Accession 0139508)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  8. Satellite Ocean Heat Content Suite from 2016-07-01 to 2016-07-31 (NCEI Accession 0156208)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  9. Satellite Ocean Heat Content Suite from 2015-04-01 to 2015-04-30 (NCEI Accession 0139405)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  10. Satellite Ocean Heat Content Suite from 2016-05-01 to 2016-05-31 (NCEI Accession 0152451)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  11. Satellite Ocean Heat Content Suite from 2013-03-01 to 2013-03-31 (NCEI Accession 0139507)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  12. Satellite Ocean Heat Content Suite from 2015-08-01 to 2015-08-31 (NCEI Accession 0139409)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  13. Satellite Ocean Heat Content Suite from 2013-09-01 to 2013-09-27 (NCEI Accession 0139523)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  14. Satellite Ocean Heat Content Suite from 2014-06-01 to 2014-06-30 (NCEI Accession 0139525)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  15. Satellite Ocean Heat Content Suite from 2016-03-01 to 2016-03-30 (NCEI Accession 0145951)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  16. Satellite Ocean Heat Content Suite from 2012-08-27 to 2012-08-31 (NCEI Accession 0139500)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  17. Satellite Ocean Heat Content Suite from 2015-05-01 to 2015-05-31 (NCEI Accession 0139406)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  18. Satellite Ocean Heat Content Suite from 2012-10-01 to 2012-10-31 (NCEI Accession 0139502)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  19. Satellite Ocean Heat Content Suite from 2014-04-01 to 2014-04-30 (NCEI Accession 0139521)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  20. Satellite Ocean Heat Content Suite from 2014-02-01 to 2014-02-28 (NCEI Accession 0139524)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  1. Satellite Ocean Heat Content Suite from 2015-02-01 to 2015-02-28 (NCEI Accession 0139403)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  2. Satellite Ocean Heat Content Suite from 2014-11-01 to 2014-11-30 (NCEI Accession 0139389)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  3. Satellite Ocean Heat Content Suite from 2013-06-01 to 2013-06-30 (NCEI Accession 0139510)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  4. Satellite Ocean Heat Content Suite from 2016-09-01 to 2016-09-30 (NCEI Accession 0156679)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  5. Satellite Ocean Heat Content Suite from 2013-11-01 to 2013-11-30 (NCEI Accession 0139517)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  6. Satellite Ocean Heat Content Suite from 2014-08-01 to 2014-08-31 (NCEI Accession 0139313)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) Product generated by NOAA National Environmental Satellite, Data, and...

  7. Satellite Ocean Heat Content Suite from 2015-09-01 to 2015-09-30 (NCEI Accession 0139410)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  8. Satellite Ocean Heat Content Suite from 2015-01-01 to 2015-01-31 (NCEI Accession 0139402)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains an operational Satellite Ocean Heat Content Suite (SOHCS) product generated by NOAA National Environmental Satellite, Data, and...

  9. Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Latent Heating Profiles

    Science.gov (United States)

    Grecu, Mircea; Olson, William S.; Shie, Chung-Lin; L'Ecuyer, Tristan S.; Tao, Wei-Kuo

    2009-01-01

    In this study, satellite passive microwave sensor observations from the TRMM Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates. 2

  10. 2015 German refrigeration and air conditioning meeting. Abstracts; Deutsche Kaelte- und Klimatagung 2015. Kurzfassungen

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    The volume contains the abstracts of the 2015 German refrigeration and air conditioning meeting in 5 chapters: cryo-technology, fundamentals of materials for refrigeration engineering and heat pump technology, facilities and components for the refrigeration and heat pump technology; application of refrigeration engineering; air conditioning technology and heat pump application.

  11. Heat flux anomalies in Antarctica revealed from satellite magnetic data

    DEFF Research Database (Denmark)

    Maule, Cathrine Fox; Purucker, Michael E.; Olsen, Nils

    2005-01-01

    The geothermal heat flux is an important factor in the dynamics of ice sheets; it affects the occurrence of subglacial lakes, the onset of ice streams, and mass losses from the ice sheet base. Because direct heat flux measurements in ice-covered regions are difficult to obtain, we developed a met...

  12. Performance modeling of optical refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Mills, G.; Mord, A. [Ball Aerospace and Technologies Corp., Boulder, CO (United States). Cryogenic and Thermal Engineering

    2006-02-15

    Optical refrigeration using anti-Stokes fluorescence in solids has several advantages over more conventional techniques including low mass, low volume, low cost and no vibration. It also has the potential of allowing miniature cryocoolers on the scale of a few cubic centimeters. It has been the topic of analysis and experimental work by several organizations. In 2003, we demonstrated the first optical refrigerator. We have developed a comprehensive system-level performance model of optical refrigerators. Our current version models the refrigeration cycle based on the fluorescent material emission and absorption data at ambient and reduced temperature for the Ytterbium-ZBLAN glass (Yb:ZBLAN) cooling material. It also includes the heat transfer into the refrigerator cooling assembly due to radiation and conduction. In this paper, we report on modeling results which reveal the interplay between size, power input, and cooling load. This interplay results in practical size limitations using Yb:ZBLAN. (author)

  13. Superfluid thermodynamic cycle refrigerator

    Science.gov (United States)

    Swift, Gregory W.; Kotsubo, Vincent Y.

    1992-01-01

    A cryogenic refrigerator cools a heat source by cyclically concentrating and diluting the amount of .sup.3 He in a single phase .sup.3 He-.sup.4 He solution. The .sup.3 He in superfluid .sup.4 He acts in a manner of an ideal gas in a vacuum. Thus, refrigeration is obtained using any conventional thermal cycle, but preferably a Stirling or Carnot cycle. A single phase solution of liquid .sup.3 He at an initial concentration in superfluid .sup.4 He is contained in a first variable volume connected to a second variable volume through a superleak device that enables free passage of .sup.4 He while restricting passage of .sup.3 He. The .sup.3 He is compressed (concentrated) and expanded (diluted) in a phased manner to carry out the selected thermal cycle to remove heat from the heat load for cooling below 1 K.

  14. 2014 German refrigeration and air conditioning meeting. Proceedings; Deutsche Kaelte- und Klimatagung 2014. Tagungsbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    The proceedings of the 2014 German refrigeration and air conditioning meeting contain contributions on the following topics: cryotechnology, fundamentals and materials for the refrigeration and heat pump technology, devices and components for the refrigeration and heat pump technology, applications of refrigeration technologies, air conditioning technology and heat pump applications, cryotechnology in biology and medicine, heat transfer and ventilation, guidelines and legal topics, refrigerant fluid - oil mixtures, control and surveillance, simulation and control, ambient air.

  15. Floating loop method for cooling integrated motors and inverters using hot liquid refrigerant

    Science.gov (United States)

    Hsu, John S.; Ayers, Curtis W.; Coomer, Chester; Marlino, Laura D.

    2007-03-20

    A method for cooling vehicle components using the vehicle air conditioning system comprising the steps of: tapping the hot liquid refrigerant of said air conditioning system, flooding a heat exchanger in the vehicle component with said hot liquid refrigerant, evaporating said hot liquid refrigerant into hot vapor refrigerant using the heat from said vehicle component, and returning said hot vapor refrigerant to the hot vapor refrigerant line in said vehicle air conditioning system.

  16. Two-Phase Flow in High-Heat-Flux Micro-Channel Heat Sink for Refrigeration Cooling Applications. Part 1: Micro-Channel Heat Sink for Direct Refrigeration Cooling

    Science.gov (United States)

    2008-09-01

    relation [Shah and London (1978), Incropera and Dewitt (2002)]: Boiling and Two-Phase Flow Laboratory 21 AP,pg = L- fsp.,G 2V, (1.3.4) where f,,.,Reg = 24...1.4.1) where q is the fin efficiency. Since the top wall is adiabatic, the fin efficiency is given by [ Incropera and Dewitt (2002)] tanh (m Hh...phase convection heat transfer coefficient prevalent in the highly subcooled inlet is given by the relation ( Incropera and Dewitt, 2002) Nu = -h D

  17. 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.

  18. 液化天然气(LNG)冷藏车冷量回收换热器的设计%The design of heat exchanger for cold energy recover in LNG refrigerated truck

    Institute of Scientific and Technical Information of China (English)

    张哲; 郭永刚; 田津津; 毛力

    2012-01-01

    Liquid natural gas (LNG) can provide plenty of cold energy when it is used as the fuel. The cold energy can be recovered and utilized in refrigerated track refrigeration. LNC refrigerated truck can effectively save energy and avoid the ozone layer depletion and greenhouse effect. Traditionally, cold energy is recovered after direct gasification of LNG, which is happened in cold energy recover heat exchanger. However, frost is easily formed in the heat exchanger surface in this system and cause the performance of heat exchanger to decline. This paper proposed a method, which heat pipe technology was used to recover the cold energy released by UVG and achieve refrigeration in refrigerated truck. Besides, a new type of heat - pipe - based heat exchanger for LNG cold energy recover was designed. The new type of heat exchanger has high efficiency and compact characteristic.%液化天然气(LNG)用做优质“绿色”汽车燃料的同时,还具有大量的冷能,该冷能可回收用于冷藏车制冷,LNG冷藏车是一种节能环保型汽车.在LNG冷藏车冷量回收系统中,传统的方式是将LNG在换热器中直接气化,并向空气释放冷量,但这种方式中的换热器表面易结霜,对其性能造成很大危害.文中提出了采用热管技术回收LNG冷量并用于冷藏车制冷的方法;设计了新型的热管式LNG冷量回收换热器,该新型换热器具有高效、紧凑等特点.

  19. Refrigeration Showcases

    Science.gov (United States)

    1997-01-01

    Through the Technology Affiliates Program at the Jet Propulsion Laboratory (JPL), valuable modifications were made to refrigerator displays built by Displaymor Manufacturing Company, Inc. By working with JPL, Displaymor could address stiffer requirements that ensure the freshness of foods. The application of the space technology meant that the small business would be able to continue to market its cases without incurring expenses that could threaten the viability of the business, and the future of several dozen jobs. Research and development improvements in air flow distribution and refrigeration coil technology contributed greatly to certifying Displaymor's showcases given the new federal regulations. These modifications resulted in a refrigerator case that will keep foods cooler, longer. Such changes maintained the openness of the display, critical to customer visibility and accessibility, impulse buying, and cross-merchandising.

  20. Available energy analysis of new tandem double-capillary tube refrigeration system for refrigerator-freezers

    Institute of Scientific and Technical Information of China (English)

    Maogang HE; Xinzhou SONG; Ying ZHANG; Jiantao ZHANG

    2008-01-01

    A new tandem double-capillary tube refri-geration system for refrigerator-freezers is proposed. A capillary tube was added between the two evaporators in the fresh and frozen food storage chests to raise the evaporation temperature of the refrigerating chamber, and reduce the heat exchange temperature difference and the available energy loss. Peng-Robinson (P-R) equation of state was adopted to calculate the thermodynamic properties of the refrigerants, and the available energy analysis of the vapor compression refrigeration cycle was programmed to calculate the thermodynamic perfor-mances of the new and the conventional refrigeration cycle of the refrigerator-freezer. The calculation results show that the available energy efficiency of the conven-tional refrigeration cycle of the refrigerator-freezer is 21.20% and 20.57%, respectively when the refrigerant is R12 and R134a, while that of the double-capillary tube refrigeration cycle of the refrigerator-freezer is 23.97% and 23.44%, respectively. By comparison, the available energy efficiency of the new refrigeration system increases by 13.07% and 13.95%, respectively.

  1. THERMODYNAMIC ANALYSIS OF REFRIGERANT MIXTURES IN VAPOR COMPRESSION REFRIGERATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Erol ARCAKLIOĞLU

    2003-02-01

    Full Text Available In this study, performance analysis of vapor-compression refrigeration system with suction/liquid line heat exchanger has been realized with the calculations of the coefficient of performance, and volumetric refrigeration capacity values using different refrigerant mixtures. Refrigerants R12, R22, and R502 of CFCs, R134a, R152a, R125, R143a, and R32 of HFCs, R600a, and R290 of HCs, and their binary, ternary, and mixtures of different mass ratios have been used as working fluids. In order to decrease global pollution due to CFCs in accordance with Montreal Protocol in 1987, it is considered to use the refrigerant mixtures of HFCs, and HCs instead of CFCs (R12, R22, and R502. For this reason, the performance comparison of the new mixtures with CFC refrigerants has been done in the frame of this study. To compare the performance values, constant temperature method has been used. Thermodynamic properties of refrigerants that were used in the performance calculations have been taken from REFPROP 6.01. For this aim, new software has written in FORTRAN programing language using sub-programs of REFPROP, and all related calculations of performance have been achieved by this software.

  2. Education in Helium Refrigeration

    Science.gov (United States)

    Gistau Baguer, G. M.

    2004-06-01

    On the one hand, at the end of the time I was active in helium refrigeration, I noticed that cryogenics was stepping into places where it was not yet used. For example, a conventional accelerator, operating at room temperature, was to be upgraded to reach higher particle energy. On the other hand, I was a little bit worried to let what I had so passionately learned during these years to be lost. Retirement made time available, and I came gradually to the idea to teach about what was my basic job. I thought also about other kinds of people who could be interested in such lessons: operators of refrigerators or liquefiers who, often by lack of time, did not get a proper introduction to their job when they started, young engineers who begin to work in cryogenics… and so on. Consequently, I have assembled a series of lessons about helium refrigeration. As the audiences have different levels of knowledge in the field of cryogenics, I looked for a way of teaching that is acceptable for all of them. The course is split into theory of heat exchangers, refrigeration cycles, technology and operation of main components, process control, and helium purity.

  3. The Technique and Application of Heating and Refrigeration by Geothermal Energy%地热能供暖制冷技术及应用

    Institute of Scientific and Technical Information of China (English)

    宫自强; 张云鹏; 侯艳

    2012-01-01

    Based on the current energy crisis, this article discussed the possib!!ity of construction energy conservation by comprehensive utilization of geothermal energy. It also discussed the multi - applications for geothermal energy refrigeration, geothermal energy heat- ing and geothermal energy water supply by one system.%本文从我国的能源现状出发,讨论了如何通过地热能综合利用来实现建筑节能。探讨了如何采用一机多用的方案,使其既能用于地热能制冷,又可以用于地热能采暖和热水供给。

  4. Refrigeration Servicing.

    Science.gov (United States)

    Hamilton, Donald L.; And Others

    This self-study course is designed to familiarize Marine enlisted personnel with the services required to be performed on refrigeration equipment. The course contains four study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the unit. The study units are divided into numbered work…

  5. REFRIG-12: A graphics-augmented interactive program for designing vapor-compression refrigeration/heat pump cycles

    Science.gov (United States)

    Davis, B. W.

    1984-09-01

    REFRIG-12 is an interactive program that serves as a tool for designing and analyzing thermodynamic vapor compression refrigeration/heatpump cycles. Graphic and alphanumeric responses to design decisions are displayed simultaneously on separate monitors. Temperature-Entropy property coordinates are used to describe the thermodynamic processes Freon-12 undergoes as it passes through the various mechanical components which ultimately produce the cycle. The processes are displayed graphically as the user makes the decisions to design a refrigeration cycle. When a design has been completed, REFRIG-12 offers the user an opportunity to make changes. The effects of design changes become graphically discernible through successive overlays on the graphics monitor. DOTPLOT can be executed to produce a hard copy of the graphics monitor display. Summaries of the cycle performance, pertinent energy transfers, and other engineering consequences of the design specifications can also be presented - at user option - on both the CRT and the printer. REFRIG-12 is organized so that a relatively small main program controls 25 subroutines. Each subroutine has stand alone characteristics and may be used with programs having other primary purposes. The subroutines can be conveniently merged (or chained) into system memory as needed.

  6. Study, optimization, and design of a laser heat engine. [for satellite applications

    Science.gov (United States)

    Taussig, R. T.; Cassady, P. E.; Zumdieck, J. F.

    1978-01-01

    Laser heat engine concepts, proposed for satellite applications, are analyzed to determine which engine concept best meets the requirements of high efficiency (50 percent or better), continuous operation in space using near-term technology. The analysis of laser heat engines includes the thermodynamic cycles, engine design, laser power sources, collector/concentrator optics, receiving windows, absorbers, working fluids, electricity generation, and heat rejection. Specific engine concepts, optimized according to thermal efficiency, are rated by their technological availability and scaling to higher powers. A near-term experimental demonstration of the laser heat engine concept appears feasible utilizing an Otto cycle powered by CO2 laser radiation coupled into the engine through a diamond window. Higher cycle temperatures, higher efficiencies, and scalability to larger sizes appear to be achievable from a laser heat engine design based on the Brayton cycle and powered by a CO laser.

  7. Energy saving and waste heat recovery within the refrigeration and cold storage sector in Lithuania. Final report for fact finding mission

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    This is the final report for the Fact Finding Mission, which is the first part of the demonstration project in Energy Saving and Waste Heat recovery within the Refrigeration and Cold Storage Sector in Lithuania. The purpose of this first part of the project, The Fact Finding Mission, is the identification and recommendation of one (possibly two) companies for implementation of a demonstration project. The recommendation is based partly on the strictly technical possibilities of implementation of a demonstration project within Energy Saving and Waste Heat Recovery, but also on the interest of the companies in the implementation of this type of measures as well as their possibilities of financing. The result of The Fact Finding Mission is a recommendation for the implementation of a demonstration project at the slaughtering and meat processing company `Taurage Maistas`, for which it is estimated that there are good possibilities of implementing measures for reduction of the energy consumption and utilisation of the generated waste heat. Also, the company is considered by the authorities to be a financially well functioning company. For examples a privatisation process has already been carried out and within a few years the company has turned a deficit to a profit and increased the turnover by approx. 33%. (EG)

  8. Not all counterclockwise thermodynamic cycles are refrigerators

    Science.gov (United States)

    Dickerson, R. H.; Mottmann, J.

    2016-06-01

    Clockwise cycles on PV diagrams always represent heat engines. It is therefore tempting to assume that counterclockwise cycles always represent refrigerators. This common assumption is incorrect: most counterclockwise cycles cannot be refrigerators. This surprising result is explored here for quasi-static ideal gas cycles, and the necessary conditions for refrigeration cycles are clarified. Three logically self-consistent criteria can be used to determine if a counterclockwise cycle is a refrigerator. The most fundamental test compares the counterclockwise cycle with a correctly determined corresponding Carnot cycle. Other criteria we employ include a widely accepted description of the functional behavior of refrigerators, and a corollary to the second law that limits a refrigerator's coefficient of performance.

  9. Refrigeration and Food Safety

    Science.gov (United States)

    ... Standard Forms FSIS United States Department of Agriculture Food Safety and Inspection Service About FSIS District Offices Careers ... Viewer (JSR 286) Actions ${title} Loading... Refrigeration and Food Safety History of Refrigeration Importance of Refrigeration Types of ...

  10. Analysis of Combined Power and Refrigeration Generation Using the Carbon Dioxide Thermodynamic Cycle to Recover the Waste Heat of an Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Shunsen Wang

    2014-01-01

    Full Text Available A novel thermodynamic system is proposed to recover the waste heat of an internal combustion engine (ICE by integrating the transcritical carbon dioxide (CO2 refrigeration cycle with the supercritical CO2 power cycle, and eight kinds of integration schemes are developed. The key parameters of the system are optimized through a genetic algorithm to achieve optimum matching with different variables and schemes, as well as the maximum net power output (Wnet. The results indicate that replacing a single-turbine scheme with a double-turbine scheme can significantly enhance the net power output (Wnet and lower the inlet pressure of the power turbine (P4. With the same exhaust parameters of ICE, the maximum Wnet of the double-turbines scheme is 40%–50% higher than that of the single-turbine scheme. Replacing a single-stage compression scheme with a double-stage compression scheme can also lower the value of P4, while it could not always significantly enhance the value of Wnet. Except for the power consumption of air conditioning, the net power output of this thermodynamic system can reach up to 13%–35% of the engine power when it is used to recover the exhaust heat of internal combustion engines.

  11. Research on rotary kiln surface heat absorption refrigeration technology%水泥回转窑筒体表面余热吸收式制冷技术研究

    Institute of Scientific and Technical Information of China (English)

    陈华东

    2014-01-01

    Cement production industry is a high energy consumption industry, and the loss rate of rotary kiln surface in whole imput en-ergy is high up to 10%. By setting heat gathering cover on rotary kiln surface, 100℃hot water can be gained. Using the hot water in lithium bromide absorption refrigeration unit, cooling capacity of 1 516 kW can be obtained. Compared with ordinary air-conditioning and electric compressor refrigeration technology, refrigeration by lithium bromide absorption refrigeration technology using rotary kiln surface waste heat can save 200,000 RMB every summer.%水泥生产是一个高耗能的行业,回转窑筒体表面的余热损失可达输入能量的10%。通过在回转窑表面布置集热罩,可得到平均温度为100℃的热水。这些热水用于溴化锂吸收式制冷机组,可以得到制冷量1516 kW,相较于普通空调和电动压缩机制冷技术,采用溴化锂吸收式制冷技术回收回转窑表面余热进行制冷每年夏天可以节省20万元左右电费。

  12. 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.

  13. Evaluation and Application of Satellite-Based Latent Heating Profile Estimation Methods

    Science.gov (United States)

    Olson, William S.; Grecu, Mircea; Yang, Song; Tao, Wei-Kuo

    2004-01-01

    In recent years, methods for estimating atmospheric latent heating vertical structure from both passive and active microwave remote sensing have matured to the point where quantitative evaluation of these methods is the next logical step. Two approaches for heating algorithm evaluation are proposed: First, application of heating algorithms to synthetic data, based upon cloud-resolving model simulations, can be used to test the internal consistency of heating estimates in the absence of systematic errors in physical assumptions. Second, comparisons of satellite-retrieved vertical heating structures to independent ground-based estimates, such as rawinsonde-derived analyses of heating, provide an additional test. The two approaches are complementary, since systematic errors in heating indicated by the second approach may be confirmed by the first. A passive microwave and combined passive/active microwave heating retrieval algorithm are evaluated using the described approaches. In general, the passive microwave algorithm heating profile estimates are subject to biases due to the limited vertical heating structure information contained in the passive microwave observations. These biases may be partly overcome by including more environment-specific a priori information into the algorithm s database of candidate solution profiles. The combined passive/active microwave algorithm utilizes the much higher-resolution vertical structure information provided by spaceborne radar data to produce less biased estimates; however, the global spatio-temporal sampling by spaceborne radar is limited. In the present study, the passive/active microwave algorithm is used to construct a more physically-consistent and environment-specific set of candidate solution profiles for the passive microwave algorithm and to help evaluate errors in the passive algorithm s heating estimates. Although satellite estimates of latent heating are based upon instantaneous, footprint- scale data, suppression

  14. 两级双效溴化锂制冷-热泵复合循环%Hybrid Two-stage and Double-effect Lithium Bromide Refrigeration-heat Pump Compound Cycle

    Institute of Scientific and Technical Information of China (English)

    黄少君; 卢玫; 朱家贤; 李凌

    2012-01-01

    在热电冷联产系统中,溴化锂吸收式制冷机在制冷过程中排放了大量的废热,这些废热品味低,难以直接回收利用.在此提出了两级双效溴化锂制冷-热泵复合循环,该循环具有冷凝温度较高的特点,便于直接回收冷凝排放热.系统以背压汽轮机的背压蒸汽为热源,制冷的同时利用循环所排出的废热加热锅炉补充水至较高温度.以具有相同功效的双效溴冷机与单效溴化锂热泵联合运行作为对比循环,制冷-热泵复合循环系统省去了一台蒸发器与冷凝器,减少了两个换热温差,并且通过热力计算、能量分析和(火用)分析表明,该循环的能量利用率与(火用)效率均有很大的提高,(火用)效率比对比循环提高了45%.%CCHP system, The waste heat quantity emitted from lithium bromide absorption refrigeration is large and low grade, so it is difficult to use directly. This paper proposes a hybrid two-stage and double-effect Lithium Bromide refrigeration - heat pump compound cycle. In this cycle, the condenser could emit higher temperature heat, which could increase the utilization rate of emitted waste heat. The cycle's heat source is the back pressure steam, and it can take advantage of the low-grade thermal energy emitted from the refrigeration process to heat up the boiler make-up water. This paper takes existiag double-effect lithium bromide absorption refrigeration and the single effect lithium bromide heat pump as contrast, the refrigeration - heat pump compound cycle system omits an evaporator and a condenser, which could decrease the temperature difference in heat exchange. And the energy analysis and the exergy analysis show that the compound cycle can improve exergy efficiency and energy utilization efficiency.

  15. Managing Refrigerant Emissions

    Science.gov (United States)

    Access information on EPA's efforts to address ozone layer depletion by reducing emissions of refrigerants from stationary refrigeration and air conditioning systems and motor vehicle air conditioning systems.

  16. 利用汽车余热的吸收式制冷系统的研究%Study on LiBr Absorption Refrigeration System with Automotive Engines’ Exhausted Heat

    Institute of Scientific and Technical Information of China (English)

    李小华; 唐景立

    2013-01-01

      根据奇瑞A3轿车空调系统和冷却水及排气系统的结构特点,结合溴化锂吸收式制冷系统的工作原理,提出将汽车排气管和发动机冷却水箱进行结构改造作为溴化锂吸收式制冷机的发生器,代替传统的汽车空调系统和发动机的冷却系统。并应用工程热力学、传热学和流体力学的方法对溴化锂吸收式制冷机和现有的空调系统进行热力计算和各传热设备的传热面积计算,并进行了比较,结果表明:单效溴化锂吸收式冷热水机组在汽车空调系统中的应用是可行的,并且溴化锂制冷机组结构紧凑,使原有的汽车空调系统小型化。%Based on the structure and characteristic of automotive refrigeration system and engine circulation cooling water system and exhausted heat system, combing the working principle of lithium bromide absorption refrigeration system, the authors used the automotive exhaust pipe and cooling water tank improved as the generator of the lithium bromide absorption refrigeration system, which might realize the objective with the lithium bromide absorption hot-cold water unit to replace the automobile air conditioning refrigeration and heating system and the automobile engine cooling system. The methods of thermodynamics, heat transfer, and hydrodynamics are used to do the computation of the thermodynamic and the heat transfer area of the lithium bromide absorption refrigeration system. And has carried on the comparison with the existing air-conditioning system, the results show LiBr Absorption Refrigeration System with Automotive Engines’ Exhausted Heat is feasible, and its system structure is simple.

  17. Low-temperature magnetic refrigerator

    Science.gov (United States)

    Barclay, John A.

    1985-01-01

    The disclosure is directed to a low temperature 4 to 20 K. refrigeration apparatus and method utilizing a ring of magnetic material moving through a magnetic field. Heat exchange is accomplished in and out of the magnetic field to appropriately utilize the device to execute Carnot and Stirling cycles.

  18. Influence of Oil on Refrigerant Evaporator Performance

    Science.gov (United States)

    Kim, Jong-Soo; Nagata, Karsuya; Katsuta, Masafumi; Tomosugi, Hiroyuki; Kikuchi, Kouichiro; Horichi, Toshiaki

    In vapor compression refrigeration system using oil-lubricated compressors, some amount of oil is always circulated through the system. Oil circulation can have a significant influence on the evaporator performance of automotive air conditioner which is especially required to cool quickly the car interior after a period standing in the sun. An experimental investigation was carried out an electrically heated horizontal tube to measure local heat transfer coefficients for various flow rates and heat fluxes during forced convection boiling of pure refrigerant R12 and refrigerant-oil mixtures (0-11% oil concentration by weight) and the results were compared with oil free performance. Local heat transfer coefficients increased at the region of low vapor quality by the addition of oil. On the other hand, because the oil-rich liquid film was formed on the heat transfer surface, heat transfer coefficients gradually decreased as the vapor quality became higher. Average heat transfer coefficient reached a maximum at about 4% oil concentration and this trend agreed well with the results of Green and Furse. Previous correlations, using the properties of the refrigerant-oil mixture, could not predict satisfactorily the local heat transfer coefficients data. New correlation modified by oil concentration factor was developed for predicting the corresponding heat transfer coefficient for refrigerant-oil mixture convection boiling. The maximum percent deviation between predicted and measured heat transfer coefficient was within ±30%.

  19. Satellite DNA Modulates Gene Expression in the Beetle Tribolium castaneum after Heat Stress.

    Science.gov (United States)

    Feliciello, Isidoro; Akrap, Ivana; Ugarković, Đurđica

    2015-08-01

    Non-coding repetitive DNAs have been proposed to perform a gene regulatory role, however for tandemly repeated satellite DNA no such role was defined until now. Here we provide the first evidence for a role of satellite DNA in the modulation of gene expression under specific environmental conditions. The major satellite DNA TCAST1 in the beetle Tribolium castaneum is preferentially located within pericentromeric heterochromatin but is also dispersed as single repeats or short arrays in the vicinity of protein-coding genes within euchromatin. Our results show enhanced suppression of activity of TCAST1-associated genes and slower recovery of their activity after long-term heat stress relative to the same genes without associated TCAST1 satellite DNA elements. The level of gene suppression is not influenced by the distance of TCAST1 elements from the associated genes up to 40 kb from the genes' transcription start sites, but it does depend on the copy number of TCAST1 repeats within an element, being stronger for the higher number of copies. The enhanced gene suppression correlates with the enrichment of the repressive histone marks H3K9me2/3 at dispersed TCAST1 elements and their flanking regions as well as with increased expression of TCAST1 satellite DNA. The results reveal transient, RNAi based heterochromatin formation at dispersed TCAST1 repeats and their proximal regions as a mechanism responsible for enhanced silencing of TCAST1-associated genes. Differences in the pattern of distribution of TCAST1 elements contribute to gene expression diversity among T. castaneum strains after long-term heat stress and might have an impact on adaptation to different environmental conditions.

  20. Satellite DNA Modulates Gene Expression in the Beetle Tribolium castaneum after Heat Stress.

    Directory of Open Access Journals (Sweden)

    Isidoro Feliciello

    2015-08-01

    Full Text Available Non-coding repetitive DNAs have been proposed to perform a gene regulatory role, however for tandemly repeated satellite DNA no such role was defined until now. Here we provide the first evidence for a role of satellite DNA in the modulation of gene expression under specific environmental conditions. The major satellite DNA TCAST1 in the beetle Tribolium castaneum is preferentially located within pericentromeric heterochromatin but is also dispersed as single repeats or short arrays in the vicinity of protein-coding genes within euchromatin. Our results show enhanced suppression of activity of TCAST1-associated genes and slower recovery of their activity after long-term heat stress relative to the same genes without associated TCAST1 satellite DNA elements. The level of gene suppression is not influenced by the distance of TCAST1 elements from the associated genes up to 40 kb from the genes' transcription start sites, but it does depend on the copy number of TCAST1 repeats within an element, being stronger for the higher number of copies. The enhanced gene suppression correlates with the enrichment of the repressive histone marks H3K9me2/3 at dispersed TCAST1 elements and their flanking regions as well as with increased expression of TCAST1 satellite DNA. The results reveal transient, RNAi based heterochromatin formation at dispersed TCAST1 repeats and their proximal regions as a mechanism responsible for enhanced silencing of TCAST1-associated genes. Differences in the pattern of distribution of TCAST1 elements contribute to gene expression diversity among T. castaneum strains after long-term heat stress and might have an impact on adaptation to different environmental conditions.

  1. A versatile magnetic refrigeration test device.

    Science.gov (United States)

    Bahl, C R H; Petersen, T F; Pryds, N; Smith, A

    2008-09-01

    A magnetic refrigeration test device has been built and tested. The device allows variation and control of many important experimental parameters, such as the type of heat transfer fluid, the movement of the heat transfer fluid, the timing of the refrigeration cycle, and the magnitude of the applied magnetic field. An advanced two-dimensional numerical model has previously been implemented in order to help in the optimization of the design of a refrigeration test device. Qualitative agreement between the results from model and the experimental results is demonstrated for each of the four different parameter variations mentioned above.

  2. A versatile magnetic refrigeration test device

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Petersen, Thomas Frank; Pryds, Nini

    2008-01-01

    A magnetic refrigeration test device has been built and tested. The device allows variation and control of many important experimental parameters, such as the type of heat transfer fluid, the movement of the heat transfer fluid, the timing of the refrigeration cycle, and the magnitude...... of the applied magnetic field. An advanced two-dimensional numerical model has previously been implemented in order to help in the optimization of the design of a refrigeration test device. Qualitative agreement between the results from model and the experimental results is demonstrated for each of the four...

  3. 微通道换热器在制冷空调系统中的应用分析%Application analysis for micro - channel heat exchanger in refrigeration and air - conditioning system

    Institute of Scientific and Technical Information of China (English)

    张超; 刘婷; 周光辉

    2011-01-01

    The implementation of new energy consumption standard on June 1, 2010 has further promoted the refrigeration and air - conditioning industry upgrade. Micro - channel heat exchanger with many characteristics such as small volume, light weight, compact structure, sustaining high operating pressure, low thermal resistance and good effect on heat transfer has been gradually applied in automotive, household and commercial refrigeration and air - conditioning system. However, the domestic studies in this field start later than the foreign one, and the theoretical and experimental research are scarce. In this paper, the previous research of micro - channel heat exchanger in refrigeration and air - conditioning system was summarized and analyzed. And the difficulties in the field were pointed out, which could provide references for further application of micro - channel heat exchanger in refrigeration and air - conditioning system.%2010年6月1日实施的新能耗标准进一步推动了制冷空调行业的升级,微通道换热器以其体积小、重量轻、结构紧凑、耐高压、热阻低、换热效果好等特点开始逐步在汽车制冷空调系统、家用和商用制冷空调系统中得以应用.然而,国内在该领域的研究比国外起步晚,理论和实验研究都比较缺乏.文中对微通道换热器在制冷空调系统中的应用研究进行了总结分析,指出了该研究领域的研究热点,为其进一步的应用研究提供了参考.

  4. Air-to-water heat pumps, business for refrigeration systems experts. Marketing of energy-efficient technology; Luft/Wasser-Waermepumpen. Ein Geschaeft fuer Kaelteanlagenbauer. Vermarktung von energieeffizienter Technik

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2009-01-15

    Many providers of refrigerating systems are already active in the private customer market offering split systems. There are less of them in the field of air-to-water heat pumps although this is also a growing market, and some producers of the air conditioning sector are already offering complete solutions. The contribution presents some sales arguments, outlines marketing tools for fitters - illustrated by the example of one provider -, and closes with a short market review. (orig.)

  5. Optimizing the Thermoacoustic Pulse Tube Refrigerator Performances

    Directory of Open Access Journals (Sweden)

    E. V. Blagin

    2014-01-01

    Full Text Available The article deals with research and optimization of the thermoacoustic pulse tube refrigerator to reach a cryogenic temperature level. The refrigerator is considered as a thermoacoustic converter based on the modified Stirling cycle with helium working fluid. A sound pressure generator runs as a compressor. Plant model comprises an inner heat exchanger, a regenerative heat exchanger, a pulse tube, hot and cold heat exchangers at its ends, an inertial tube with the throttle, and a reservoir. A model to calculate the pulse tube thermoacoustic refrigerator using the DeltaEC software package has been developed to be a basis for calculation techniques of the pulse tube refrigerator. Momentum, continuity, and energy equations for helium refrigerant are solved according to calculation algorithm taking into account the porosity of regenerator and heat exchangers. Optimization of the main geometric parameters resulted in decreasing temperature of cold heat exchanger by 41,7 K. After optimization this value became equal to 115,01 K. The following parameters have been optimized: diameters of the feeding and pulse tube and heat exchangers, regenerator, lengths of the regenerator and pulse and inertial tubes, as well as initial pressure. Besides, global minimum of temperatures has been searched at a point of local minima corresponding to the optimal values of abovementioned parameters. A global-local minima difference is 0,1%. Optimized geometric and working parameters of the thermoacoustic pulse tube refrigerator are presented.

  6. Satellite-based detection of global urban heat-island temperature influence

    Science.gov (United States)

    Gallo, K.P.; Adegoke, Jimmy O.; Owen, T.W.; Elvidge, C.D.

    2002-01-01

    This study utilizes a satellite-based methodology to assess the urban heat-island influence during warm season months for over 4400 stations included in the Global Historical Climatology Network of climate stations. The methodology includes local and regional satellite retrievals of an indicator of the presence green photosynthetically active vegetation at and around the stations. The difference in local and regional samples of the normalized difference vegetation index (NDVI) is used to estimate differences in mean air temperature. Stations classified as urban averaged 0.90??C (N. Hemisphere) and 0.92??C (S. Hemisphere) warmer than the surrounding environment on the basis of the NDVI-derived temperature estimates. Additionally, stations classified as rural averaged 0.19??C (N. Hemisphere) and 0.16??C (S. Hemisphere) warmer than the surrounding environment. The NDVI-derived temperature estimates were found to be in reasonable agreement with temperature differences observed between climate stations. The results suggest that satellite-derived data sets can be used to estimate the urban heat-island temperature influence on a global basis and that a more detailed analysis of rural stations and their surrounding environment may be necessary to assure that temperature trends derived from assumed rural environments are not influenced by changes in land use/land cover. Copyright 2002 by the American Geophysical Union.

  7. A predictive model that describes the effect of prolonged heating at 70 to 90 degrees C and subsequent incubation at refrigeration temperatures on growth from spores and toxigenesis by nonproteolytic Clostridium botulinum in the presence of lysozyme.

    Science.gov (United States)

    Fernández, P S; Peck, M W

    1999-08-01

    Refrigerated processed foods of extended durability such as cook-chill and sous-vide foods rely on a minimal heat treatment at 70 to 95 degrees C and then storage at a refrigeration temperature for safety and preservation. These foods are not sterile and are intended to have an extended shelf life, often up to 42 days. The principal microbiological hazard in foods of this type is growth of and toxin production by nonproteolytic Clostridium botulinum. Lysozyme has been shown to increase the measured heat resistance of nonproteolytic C. botulinum spores. However, the heat treatment guidelines for prevention of risk of botulism in these products have not taken into consideration the effect of lysozyme, which can be present in many foods. In order to assess the botulism hazard, the effect of heat treatments at 70, 75, 80, 85, and 90 degrees C combined with refrigerated storage for up to 90 days on growth from 10(6) spores of nonproteolytic C. botulinum (types B, E, and F) in an anaerobic meat medium containing 2,400 U of lysozyme per ml (50 microg per ml) was studied. Provided that the storage temperature was no higher than 8 degrees C, the following heat treatments each prevented growth and toxin production during 90 days; 70 degrees C for >/=2,545 min, 75 degrees C for >/=463 min, 80 degrees C for >/=230 min, 85 degrees C for >/=84 min, and 90 degrees C for >/=33.5 min. A factorial experimental design allowed development of a predictive model that described the incubation time required before the first sample showed growth, as a function of heating temperature (70 to 90 degrees C), period of heat treatment (up to 2,545 min), and incubation temperature (5 to 25 degrees C). Predictions from the model provided a valid description of the data used to generate the model and agreed with observations made previously.

  8. The use of new refrigerants in high-temperature heat pumps for heating water up to 80 degrees C in chocolate factories; L`utilisation des nouveaux frigorigenes en pompes a chaleur a haute temperature : production d`eau chaude a 80 degres C en chocolaterie

    Energy Technology Data Exchange (ETDEWEB)

    Blaise; Dutto [EDF, 75 - Paris (France); Lindt; Michel [Safrair (France)

    1992-12-31

    A cascade refrigeration system utilizing a new refrigerant, R142b (difluorochloroethane), in heating and cooling of water with heat pumps, was described. R142b has been extensively tested by Electricite de France (EDF) since 1984. The heat-carrying fluid can produce hot air or water up to 90 degrees C from a source between 30 and 50 degrees C. It is non-toxic and has low ozone depleting potential and low global warming potential. The utilisation of R142b along with R22 in the industrial heat pumps installations of a French chocolate factory with demanding needs in both hot and cold water have demonstrated that it is possible to produce hot water in the range of 50 to 80 degrees C without CFCs in heat pump installations. 1 tab., 1 fig.

  9. Detection of the urban heat island in Beijing using HJ-1B satellite imagery

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Satellite images are used extensively in studying the urban heat island(UHI) phenomenon.We evaluated the suitability of thermal infrared(TIR) data from the HJ-1B satellite for detecting UHI using a case study in Beijing.Two modified algorithms for retrieving the land surface temperature(LST) from HJ-1B data were tested.The results were compared with LST images derived from a Landsat TM thermal band and the MODIS LST output.The spatial pattern of UHI generated using HJ-1B data matched well with that produced using TM and MODIS data.Of the two algorithms,the mono-window algorithm performed better but further tests are necessary.With more frequent coverage than TM and higher spatial resolution than MODIS,the HJ-1B TIR data present a unique opportunity to study thermal environments in cities in China and neighboring countries.

  10. 扩散吸收式制冷系统中板式换热器综合传热性能分析%Heat Transfer Performances of Plate Heat Exchangers Used in Diffusion-Absorption Refrigeration System

    Institute of Scientific and Technical Information of China (English)

    王寒栋

    2012-01-01

    在一种太阳能驱动、采用喷雾吸收器并以板式换热器作为主要换热部件的LiNO3-NH3-He三工质扩散吸收式制冷系统中,根据试验测得的运行参数,以溶液的p-t-x西方程及物性方程、传热基础理论等为依据,提出了计算溶液换热器中溶液流量的方法,并利用综合传热系数k、传热单元数N_TU与换热器效率s研究了板式换热器作为LiN03-NH3-He扩散吸收式制冷系统发生器、冷凝器、溶液热交换器、溶液冷却器时的换热性能.试验与分析表明,板式换热器的换热面积及其内部流道中的流量(流速)对其综合传热性能具有较大影响;在介质流量一定时,板式换热器不宜考虑过大的面积预留量;板式溶液换热器内部流道宜采用多流程布置形式以强化传热、提高换热效率.%A LiNO3-NH3-He diffusion-absorption refrigeration system driven by solar energy is introduced, in which a spray absorber is used to enhance the heat and mass transfer, and plate heat exchangers (PHEs) used as generator, condenser, solution heat exchanger (SHE) and solution cooler, respectively. Besides, solution flow rates in the system are evaluated based on p-t-x and physical property equations of LiNO3-NH3 solution, principles of heat transfer, and parameters such as pressure, temperatures and flow rates. Heat transfer performances are also investigated according to the overall heat transfer coefficient k, number of heat transfer units NTU and heat exchanger efficiency ε. Experiments and analysis show that, in LiNO3-NH3-He diffusion-absorption refrigeration system, heat transfer area and solution flow rates of PHEs affect the overall heat transfer performance of the PHEs. Therefore, extra size on PHE is not recommended if the solution flow rate is kept constant, and inner passageways of PHEs should adopt multi-pass to enhance heat transfer.

  11. COMPUTER SIMULATION OF A STIRLING REFRIGERATING MACHINE

    Directory of Open Access Journals (Sweden)

    V.V. Trandafilov

    2015-10-01

    Full Text Available In present numerical research, the mathematical model for precise performance simulation and detailed behavior of Stirling refrigerating machine is considered. The mathematical model for alpha Stirling refrigerating machine with helium as the working fluid will be useful in optimization of these machines mechanical design. Complete non-linear mathematical model of the machine, including thermodynamics of helium, and heat transfer from the walls, as well as heat transfer and gas resistance in the regenerator is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. Important design parameters are varied and their effect on Stirling refrigerating machine performance determined. The simulation results of Stirling refrigerating machine which include heat transfer and coefficient of performance are presented.

  12. ARTI refrigerant database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M.

    1996-11-15

    The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

  13. ARTI refrigerant database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M.

    1996-07-01

    The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

  14. ARTI refrigerant database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

    1999-01-01

    The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilities access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

  15. Relationship between composition of mixture charged and that in circulation in an auto refrigerant cascade and a J-T refrigerator operating in liquid refrigerant supply mode

    Science.gov (United States)

    Sreenivas, Bura; Nayak, H. Gurudath; Venkatarathnam, G.

    2017-01-01

    The composition of the refrigerant mixture in circulation during steady state operation of J-T and allied refrigerators is not the same as that charged due to liquid hold up in the heat exchangers and phase separators, as well as the differential solubility of different refrigerant components in the compressor lubricating oil. The performance of refrigerators/liquefiers operating on mixed refrigerant cycles is dependent on the mixture composition. It is therefore important to charge the right mixture that results in an optimum composition in circulation during steady state operation. The relationship between the charged and circulating composition has been experimentally studied in a J-T refrigerator operating in the liquid refrigerant supply (LRS) mode and an auto refrigerant cascade refrigerator (with a phase separator) operating in the gas refrigerant supply (GRS) mode. The results of the study are presented in this work. The results show that the method presented earlier for J-T refrigerators operating in GRS mode is also applicable in the case of refrigerators studied in this work.

  16. THE RESULTS OF THE STUDY BOILING POINT OUT OZONE-SAFE REFRIGERANT R410A IN THE EVAPORATORS OF REFRIGERATING MACHINES

    Directory of Open Access Journals (Sweden)

    V. G. Bukin

    2012-01-01

    Full Text Available The results of experimental research boiling heat transfer of ozone-friendly R410A refrigerant in evaporators machines and the possibility of its use in place of the prohibited refrigerant R22.

  17. Magnetocaloric Refrigeration.

    Science.gov (United States)

    1987-03-01

    material having a magnetocaloric effect. Larger temperature spans require a cycle with some type of heat exchange. One such cycle is the Brayton cycle... heat capacity of the rare-earth metals, which had a small magnetocaloric effect at the higher temperatures. In order to optimize the small... magnetocaloric effect and minimize the heat capacities of the inactive rare- earth metals while they are being cooled to their Curie points, half the volume of

  18. An experimental study on refrigerant distribution in a two row/four pass parallel flow minichannel heat exchanger

    Science.gov (United States)

    Byun, Ho-Won; Kim, Nae-Hyun

    2016-10-01

    R-410A distribution was experimentally studied for a parallel flow evaporator having two row/four pass configuration. The evaporator has inlet, intermediate and row-crossing headers. Tests were conducted for the mass flux from 70 to 130 kg/m2s with the quality at the inlet of 0.2 and exit superheat 5 °C. Significant heat transfer degradation (13-40 %) was realized for the two row/four pass configuration due to flow mal-distribution. Of the three insert hole sizes, 4.0 mm hole yielded the least heat transfer degradation followed by 6.0 and 2.0 mm holes. At the inlet header, more liquid flowed into upstream channels. At the intermediate headers, more liquid was supplied into downstream channels. Similar flow distribution was obtained before and after the row crossing header. Header pressure drops were obtained by subtracting the flat tube pressure drops and other minor pressure drops from measured pressure drops.

  19. Adsorption refrigeration-green cooling driven by low grade thermal energy

    Institute of Scientific and Technical Information of China (English)

    WANG Ruzhu; WANG Liwei

    2005-01-01

    As a type of environmental benign refrigeration technology powered by low grade thermal energy, adsorption refrigeration have aroused more and more attention in recent years. In this paper, the research frontiers of adsorption refrigeration, including adsorbent, adsorption theory, heat recovery process, technology of adsorber, the research achievements, and the development achievements, are summarized. Typical systems for adsorption refrigeration research facing to applications in the recent years are presented. Future applications of adsorption refrigeration are analysed.

  20. Effect of nanofluid on thermal performance of heat pipe with two evaporators; application to satellite equipment cooling

    Science.gov (United States)

    Mashaei, P. R.; Shahryari, M.

    2015-06-01

    A study on the behavior of nanofluid in a cylindrical heat pipe with two heat sources is performed to analyze the nanofluid application in heat-dissipating satellite equipment cooling. Pure water, Al2O3-water and TiO2-water nanofluids are used as working fluids. An analytical modeling is presented to predict the wall temperature profile for the heat pipe assuming saturated vapor and conduction heat transfer for porous media and wall, respectively. The effects of particle concentration levels (φ=0 (distilled water), 2, 4, and 8%), particle diameters (dp=10, 20, and 40 nm) on the local wall temperature, heat transfer coefficient, thermal resistance, and the size of the heat pipe are investigated. It is observed that the better wall temperature uniformity can be achieved using nanofluid which results in lower temperature difference between evaporators and condenser sections. Results reveal that applying nanoparticle with smaller size and higher concentration level increases heat transfer coefficient remarkably by reducing thermal resistance of saturated porous media. It is also found that the presence of nanoparticles in water can lead to a reduction in weight of heat pipe, and thus satellite, under nearly identical condition. The findings of this paper prove the potential of nanofluid in satellite equipment cooling application.

  1. Impact of cosmological satellites on the vertical heating of the Milky Way disc

    CERN Document Server

    Moetazedian, R

    2015-01-01

    We present a high resolution study of the impact of realistic satellite galaxies, extracted from cosmological simulations of Milky Way haloes including 6 Aquarius suites and Via Lactea \\rom{2}, on the dynamics of the galactic disc. The initial conditions for the multi-component Milky Way galaxy were generated using the GalIC code, to ensure a system in real equilibrium state prior to addition of satellites. The candidate subhaloes that came closer than 25 kpc to the centre of the host DM haloes, with initial mass $M_\\textrm{tid}$ $\\ge$ 10$^{8}$=0.003 $M_\\textrm{tid}$/$M_\\textrm{disc}$, were identified, inserted into our high resolution N-body simulations and evolved for 2 Gyrs. We quantified the vertical heating due to such impacts by measuring the disc thickness, root-mean-square of $z$-coordinate, and vertical velocity dispersion $\\sigma_{z}^{2}$ across the disc. According to our analysis the strength of the heating is strongly dependent on the high mass end of the subhalo distribution from the cosmological...

  2. Development of a Hydrogen and Heat Storage System for Satellite Applications

    Science.gov (United States)

    Reissner, Alexander; Pawelke, Roland; Hummel, Stefan; Gerger, Joachim; Lutz, Matthias; Farnes, Jarle; Vik, Arild; Wernhus, Ivar; Svendsen, Tjalve; Schautz, Max; Geneste, Xavier

    2014-08-01

    Next generation telecommunication satellites will demand increasingly more power in the range of 30 kW or more within the next 10 years. Battery technology that can sustain 30 kW for an eclipse length of up to 72 minutes will represent a major impact on the total mass of the satellite, even with new Li-ion battery technologies. Regenerative fuel cell systems (RFCS) were identified years ago as a possible alternative to rechargeable batteries. They consist of a dedicated fuel cell unit for electricity generation and a dedicated electrolyser which regenerates the fuel cell reactants hydrogen and oxygen from the fuel cell reaction product water. All units are integrated in a closed loop system. Nevertheless, one major drawback has been identified by several independent system studies [4,5], namely the need to dissipate large amounts of heat from the fuel cell during Eclipse. This in turn requires massive thermal hardware (mainly large radiators) that can contribute up to 50% of the system mass. FOTEC has suggested the use of metal hydrides as combined hydrogen and heat storage system to overcome this issue and is currently manufacturing a technology demonstrator within an ongoing ESA project. The status of these developments is outlined in this paper.

  3. Refrigerating machine oil

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, K.

    1981-03-17

    Refrigerating machine oil to be filled in a sealed motorcompressor unit constituting a refrigerating cycle system including an electric refrigerator, an electric cold-storage box, a small-scaled electric refrigerating show-case, a small-scaled electric cold-storage show-case and the like, is arranged to have a specifically enhanced property, in which smaller initial driving power consumption of the sealed motor-compressor and easier supply of the predetermined amount of the refrigerating machine oil to the refrigerating system are both guaranteed even in a rather low environmental temperature condition.

  4. Mathematical analysis of a Vuilleumier refrigerator.

    Science.gov (United States)

    Sherman, A.

    1971-01-01

    A comprehensive analysis of the Vuilleumier refrigerator was conducted. This analysis includes the effects of nonisothermal gas heat addition and rejection, hot and cold regenerator inefficiencies, conduction losses, and gas leakage losses. A computer program was written which solves the equations resulting from the analysis. The program calculates internal pressures, temperatures, and gas flow rates as functions of refrigerator crank angle, as well as overall refrigerator cooling load and power input. Comparisons between the program results and available data show good agreement, with a marked improvement over the predictions of the ideal model.

  5. Two-phase flow in refrigeration systems

    CERN Document Server

    Gu, Junjie; Gan, Zhongxue

    2013-01-01

    Two-Phase Flow in Refrigeration Systems presents recent developments from the authors' extensive research programs on two-phase flow in refrigeration systems. This book covers advanced mass and heat transfer and vapor compression refrigeration systems and shows how the performance of an automotive air-conditioning system is affected through results obtained experimentally and theoretically, specifically with consideration of two-phase flow and oil concentration. The book is ideal for university postgraduate students as a textbook, researchers and professors as an academic reference book, and b

  6. Mathematical analysis of a Vuilleumier refrigerator.

    Science.gov (United States)

    Sherman, A.

    1971-01-01

    A comprehensive analysis of the Vuilleumier refrigerator was conducted. This analysis includes the effects of nonisothermal gas heat addition and rejection, hot and cold regenerator inefficiencies, conduction losses, and gas leakage losses. A computer program was written which solves the equations resulting from the analysis. The program calculates internal pressures, temperatures, and gas flow rates as functions of refrigerator crank angle, as well as overall refrigerator cooling load and power input. Comparisons between the program results and available data show good agreement, with a marked improvement over the predictions of the ideal model.

  7. Modelling refrigerant distribution in microchannel evaporators

    DEFF Research Database (Denmark)

    Brix, Wiebke; Kærn, Martin Ryhl; Elmegaard, Brian

    2009-01-01

    The effects of refrigerant maldistribution in parallel evaporator channels on the heat exchanger performance are investigated numerically. For this purpose a 1D steady state model of refrigerant R134a evaporating in a microchannel tube is built and validated against other evaporator models. A study...... of the refrigerant distribution is carried out for two channels in parallel and for two different cases. In the first case maldistribution of the inlet quality into the channels is considered, and in the second case a non-uniform airflow on the secondary side is considered. In both cases the total mixed superheat...

  8. 平行流蒸发器制冷剂侧的换热性能研究%Research and Analysis on Heat Transfer Performance of Refrigerant- side of Parallel Flow Type Evaporator

    Institute of Scientific and Technical Information of China (English)

    楼江燕; 楼华山

    2011-01-01

    Parallel flow type the micro-channel flat tube is evaporator is a compact heat exchanger. Heat and mass transfer of the refrigerant in a subject which is complex but full of application value. According to the experimen- tal study of 38 mm parallel flow evaporator in a car in this paper, it finds out that heat transfer performance achieves to the best when the refrigerant volume flow is 0.42 (L/min). Meanwhile, with the help of CFD (Compu- tational Fluid Dynamics) numerical simulation analysis, it has shown that setting the throttle ring in current collec- tor can not only control the uniform distribution of refrigerant in the flat tube but also effectively improve the heat transfer performance. The result provides a theoretical reference for the optimization design of 38 mm parallel flow type evaporator.%平行流蒸发器是紧凑型换热器,制冷剂在微通道扁管的传热与传质是一个复杂、但有应用价值的课题.本文针对某车38mm平行流蒸发器的实验研究发现:制冷剂体积流量为0.42L/min时,换热性能达到最佳;同时借助CFD(ComputationalFluidDynamics)数值模拟分析得知:在集流管处设置节流环,可以控制制冷剂在各扁管的分布均匀,亦是提高换热性能的有效手段。为38mm平行流式蒸发器的优化设计提供理论参考.

  9. Cogeneration in breweries analysis and simulation of systems for simultaneous generation of power, heat and refrigeration using natural gas; Sistemas de refrigeracao a partir da cogeracao: analise e simulacao de propostas para o caso de cervejarias utilizando gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, Antonio Garrido

    1998-07-01

    The present work analyses some proposals of cogeneration systems for the simultaneous generation of power, heat and refrigeration in a brewery. The requirements of steam, refrigeration and electricity, as well as the production of beer in a plant of the Antarctica Company, located in Jaguariuna - SP were collected monthly for the year of 1997. Three conceptions of systems using two gas turbines with heat recovery steam generator were then proposed to meet the surveyed demand. The proposals differ in the refrigeration system: the first one uses a traditional ammonia compression system while the second uses an ammonia absorption system, the third proposal is a combination of the compression and absorption systems. These proposals are compared to the present configuration which purchases electricity from the Public Utility for power and refrigeration (using an ammonia compression)system, and fuel oil to generate steam for process heat. The technical, economical and environmental feasibility of the proposals, as well as of the present configuration are discussed on the basis of mass balances, energy balances (first law of Thermodynamics), exergy fluxes (second law analysis), operational and capital cost, based on simulation of the performance of each configuration proposed to meet the monthly electricity, steam and refrigeration requirements for the referred plant. The turbines were chosen so as to meet the peek energy demand of the plant and two cases were simulated for each proposal: turbine operational meets only the demand of the plant and turbine operates at full load, selling electricity for the Public utility. Results obtained show that the current operational costs are higher than any of the proposals presented. The high capital costs of the proposals, though,make them less interesting financially. The simulation of the case of excess electricity to the Public Utility is very attractive, considering the cost of natural gas 3,38 U$/M btu and the fare of 40 U

  10. Anomalous Brownian refrigerator

    Science.gov (United States)

    Rana, Shubhashis; Pal, P. S.; Saha, Arnab; Jayannavar, A. M.

    2016-02-01

    We present a detailed study of a Brownian particle driven by Carnot-type refrigerating protocol operating between two thermal baths. Both the underdamped as well as the overdamped limits are investigated. The particle is in a harmonic potential with time-periodic strength that drives the system cyclically between the baths. Each cycle consists of two isothermal steps at different temperatures and two adiabatic steps connecting them. Besides working as a stochastic refrigerator, it is shown analytically that in the quasistatic regime the system can also act as stochastic heater, depending on the bath temperatures. Interestingly, in non-quasistatic regime, our system can even work as a stochastic heat engine for certain range of cycle time and bath temperatures. We show that the operation of this engine is not reliable. The fluctuations of stochastic efficiency/coefficient of performance (COP) dominate their mean values. Their distributions show power law tails, however the exponents are not universal. Our study reveals that microscopic machines are not the microscopic equivalent of the macroscopic machines that we come across in our daily life. We find that there is no one to one correspondence between the performance of our system under engine protocol and its reverse.

  11. ARTI Refrigerant Database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

    1994-05-27

    The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern.

  12. Holographic Refrigerator

    CERN Document Server

    Nakamura, Shin

    2013-01-01

    We define an effective temperature and study its properties for a class of out-of-equilibrium steady states in a heat bath. Our analysis is based on the AdS/CFT correspondence, and examples include systems driven by applied electric fields and branes dragged in plasmas. We found that the effective temperature can be lower than that of the heat bath and that the out-of-equilibrium noise can be smaller than that in equilibrium. We show that a generalization of the fluctuation-dissipation relation holds for the effective temperature. In particular, we generalize the Johnson-Nyquist relation for large electric field.

  13. Theoretical study and design of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane and intended for cooling of gas transported in a gas-main pipeline

    KAUST Repository

    Petrenko, V.O.

    2011-11-01

    This paper describes the construction and performance of a novel combined system intended for natural gas transportation and power production, and for cooling of gas transported in a gas-main pipeline. The proposed system includes a gas turbine compressor, a combined electrogenerating plant and an ejector refrigeration unit operating with a hydrocarbon refrigerant. The combined electrogenerating plant consists of a high-temperature steam-power cycle and a low-temperature hydrocarbon vapor power cycle, which together comprise a binary vapor system. The combined system is designed for the highest possible effectiveness of power generation and could find wide application in gas-transmission systems of gas-main pipelines. Application of the proposed system would enable year-round power generation and provide cooling of natural gas during periods of high ambient temperature operation. This paper presents the main results of a theoretical study and design performance specifications of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane. © 2010 Elsevier Ltd and IIR. All rights reserved.

  14. Development of Magnetic Refrigerator

    Science.gov (United States)

    Ogiwara, Hiroyasu; Nakagome, Hideki; Kuriyama, Tohru

    A series of R & D of magnetic refrigerators has been done in order to realize an advanced type cryocooler for superconducting magnets of maglev trains and MRI medical system. As a result of efforts on both the magnetic refrigerator and superconducting magnets, a parasitic type magnetic refrigeration system was proposed.

  15. Thermo-refrigerating machineries. Classification; Machines thermofrigorifiques. Classification

    Energy Technology Data Exchange (ETDEWEB)

    Duminil, M. [Association Francaise du Froid (AFF), 75 - Paris (France)

    2002-07-01

    Thermo-refrigerating systems transfer the heat extracted from a cold source towards a heat source and consume thermal energy from a third source. This article proposes a classification of thermo-refrigerating systems in three categories: the systems with a changing state working fluid (physical change of the refrigerant: dissociable systems, integrated systems (ejection systems, sorption systems); chemical change of the refrigerant), the systems where the working fluid stays in the same physical state (dissociable systems (Brayton, Siemens, Stirling and Ericsson cycles), integrated systems (Vuilleumier cycle systems, thermochemical systems)) and the other systems (Seebeck thermoelectric generator with Peltier effect modules). Dissociable thermo-refrigerating systems are made of the grouping of two separate thermal machines: a thermal engine and a mechanical-refrigerating machine. (J.S.)

  16. Fully automated extraction and analysis of surface Urban Heat Island patterns from moderate resolution satellite images

    Science.gov (United States)

    Keramitsoglou, I.; Kiranoudis, C. T.

    2012-04-01

    Comparison of thermal patterns across different cities is hampered by the lack of an appropriate methodology to extract the patterns and characterize them. What is more, increased attention by the urban climate community has been expressed to assess the magnitude and dynamics of the surface Urban Heat Island effect and to identify environmental impacts of large cities and "megacities". Motivated by this need, we propose an innovative object-based image analysis procedure to extract thermal patterns for the quantitative analysis of satellite-derived land surface temperature maps. The spatial and thermal attributes associated with these objects are then calculated and used for the analyses of the intensity, the position and the spatial extent of SUHIs. The output eventually builds up and populates a database with comparable and consistent attributes, allowing comparisons between cities as well as urban climate studies. The methodology is demonstrated over the Greater Athens Area, Greece, with more than 3000 LST images acquired by MODIS over a decade being analyzed. The approach can be potentially applied to current and future (e.g. Sentinel-3) level-2 satellite-derived land surface temperature maps of 1km spatial resolution acquired over continental and coastal cities.

  17. Magnetic refrigeration materials

    Institute of Scientific and Technical Information of China (English)

    戴闻; 沈保根; 高政祥

    2001-01-01

    Magnetic refrigeration has drawn much attention because of its greater efficiency and higher reliability than the traditional gas-cycle refrigeration technology. Recently, a kind of new materials with a giant magnetocaloric effect in the subroom temperature range, Gd5 (Six Ge1- x)4, was discovered, which boosts the search for high-performance magnetic refrigerants. However, the intermetallic compounds Gd5 (SixGe1 - x )4 belong to the first order transition materials; their performance in practical magnetic refrigeration cycles remains controversial. In this paper the developing tendency of the refrigerants are discussed on the basis of our work.

  18. A Predictive Model That Describes the Effect of Prolonged Heating at 70 to 90°C and Subsequent Incubation at Refrigeration Temperatures on Growth from Spores and Toxigenesis by Nonproteolytic Clostridium botulinum in the Presence of Lysozyme

    Science.gov (United States)

    Fernández, Pablo S.; Peck, Michael W.

    1999-01-01

    Refrigerated processed foods of extended durability such as cook-chill and sous-vide foods rely on a minimal heat treatment at 70 to 95°C and then storage at a refrigeration temperature for safety and preservation. These foods are not sterile and are intended to have an extended shelf life, often up to 42 days. The principal microbiological hazard in foods of this type is growth of and toxin production by nonproteolytic Clostridium botulinum. Lysozyme has been shown to increase the measured heat resistance of nonproteolytic C. botulinum spores. However, the heat treatment guidelines for prevention of risk of botulism in these products have not taken into consideration the effect of lysozyme, which can be present in many foods. In order to assess the botulism hazard, the effect of heat treatments at 70, 75, 80, 85, and 90°C combined with refrigerated storage for up to 90 days on growth from 106 spores of nonproteolytic C. botulinum (types B, E, and F) in an anaerobic meat medium containing 2,400 U of lysozyme per ml (50 μg per ml) was studied. Provided that the storage temperature was no higher than 8°C, the following heat treatments each prevented growth and toxin production during 90 days; 70°C for ≥2,545 min, 75°C for ≥463 min, 80°C for ≥230 min, 85°C for ≥84 min, and 90°C for ≥33.5 min. A factorial experimental design allowed development of a predictive model that described the incubation time required before the first sample showed growth, as a function of heating temperature (70 to 90°C), period of heat treatment (up to 2,545 min), and incubation temperature (5 to 25°C). Predictions from the model provided a valid description of the data used to generate the model and agreed with observations made previously. PMID:10427033

  19. Prediction Of Refrigerant Thermodynamic Properties By Equations Of State

    OpenAIRE

    Moshfeghian, Mahmood Moshfeghian, Mahmood

    1992-01-01

    The ability of three equations of state (EOS) for calculating the thermodynamic properties of refrigerants has been studied for 35 pure component refrigerants. Three equations of state studied were the Soave-Redlich-Kwong (SRK), Peng-Robinson (PR) and Parameters From Group Contribution (PFGC). For each refrigerant, the vapor pressure, saturated vapor volume, saturated liquid density, and heat of vaporization were calculated and compared with the values reported in the ASHRAE hand-book. For...

  20. Refrigeration arrangement and methods for reducing charge migration

    Science.gov (United States)

    Litch, Andrew D.; Wu, Guolian

    2017-04-11

    A refrigerator appliance including a refrigerant circuit between a condenser, an evaporator, and a compressor that includes two conduits and pressure reducing devices arranged in parallel between the evaporator and the condenser. The appliance also includes a valve system to direct refrigerant through one, both or none of the conduits and pressure reducing devices, and a heat exchanging member in thermal contact with either one pressure reducing device, or one conduit between the pressure reducing device and the valve system.

  1. Satellite and ground-based sensors for the Urban Heat Island analysis in the city of Rome

    DEFF Research Database (Denmark)

    Fabrizi, Roberto; Bonafoni, Stefania; Biondi, Riccardo

    2010-01-01

    In this work, the trend of the Urban Heat Island (UHI) of Rome is analyzed by both ground-based weather stations and a satellite-based infrared sensor. First, we have developed a suitable algorithm employing satellite brightness temperatures for the estimation of the air temperature belonging...... to the layer of air closest to the surface. UHI spatial characteristics have been assessed using air temperatures measured by both weather stations and brightness temperature maps from the Advanced Along Track Scanning Radiometer (AATSR) on board ENVISAT polar-orbiting satellite. In total, 634 daytime...... and nighttime scenes taken between 2003 and 2006 have been processed. Analysis of the Canopy Layer Heat Island (CLHI) during summer months reveals a mean growth in magnitude of 3-4 K during nighttime and a negative or almost zero CLHI intensity during daytime, confirmed by the weather stations. © 2010...

  2. Determination of regional surface heat fluxes over heterogeneous landscapes by integrating satellite remote sensing with boundary layer observations

    NARCIS (Netherlands)

    Ma, Y.M.

    2006-01-01

    Keywords: satellite remote sensing, surface layer observations, atmospheric boundary layer observations, land surface variables, vegetation variables, land surface heat fluxes, validation, heterogeneous landscape, GAME/Tibet

  3. Thermoacoustically driven refrigerator with double thermoacoustic-Stirling cycles

    Science.gov (United States)

    Luo, Ercang; Dai, Wei; Zhang, Yong; Ling, Hong

    2006-02-01

    Recently, considerable research efforts have been made to search substitution technologies for chlorofluorocarbon-based vapor compression cycles due to the concern over environmental issues. This letter introduces a helium-based thermoacoustic refrigeration system, which is a thermoacoustic-Stirling refrigerator driven by a thermoacoustic-Stirling heat engine, for domestic refrigeration purpose. In the regenerators of both the refrigerator and the prime mover, helium gas experiences near to reversible high efficiency Stirling process. At the operating point with 3.0MPa mean pressure, 57.7Hz frequency, and 2.2kW heat input, the experimental cooler provides a lowest temperature of -64.4°C and 250W cooling power at -22.1°C. These results show good potential of the system to be an alternative in near future for domestic refrigeration with advantages of environment-friendliness, no moving parts, and heat driven mechanism.

  4. State of the art and trends of commercial refrigerators in shopping centers and supermarkets

    Energy Technology Data Exchange (ETDEWEB)

    Riesenbeck, G. van.

    1988-02-01

    Continuously increasing supplies of refrigerated food are a technical and economic challenge to the manufacturers of commercial refrigerators. Efforts have so far been going into the optimization of interconnected subsystems and the improvement of energy utilization, waste heat utilization (space heating, tap water heating, hot gas defrosting), low-temperature liquefaction, and electronic control systems (refrigerator units, central timers, compressor capacity for interconnected operation). Future efforts and present developments are dedicated to the improvement of heat recovery systems for heating purposes, the increase of efficiencies (multi-stage compression, flooded evaporators), monitoring of refrigerant losses, and the use of computerized control systems as well as of bigger compact control DDC systems. (HWJ).

  5. CO2 as a refrigerant

    CERN Document Server

    2014-01-01

    A first edition, the IIR guide “CO2 as a Refrigerant” highlights the application of carbon dioxide in supermarkets, industrial freezers, refrigerated transport, and cold stores as well as ice rinks, chillers, air conditioning systems, data centers and heat pumps. This guide is for design and development engineers needing instruction and inspiration as well as non-technical experts seeking background information on a specific topic. Written by Dr A.B. Pearson, a well-known expert in the field who has considerable experience in the use of CO2 as a refrigerant. Main topics: Thermophysical properties of CO2 – Exposure to CO2, safety precautions – CO2 Plant Design – CO2 applications – Future prospects – Standards and regulations – Bibliography.

  6. Elevated Heat Pump hypothesis validation by using satellite data and CMIP5 climate model simulations

    Science.gov (United States)

    Biondi, R.; Cagnazzo, C.; Cairo, F.; Fierli, F.

    2016-12-01

    Air pollution assumes an important role for the health of the south Asian countries population due to the increasing emission of atmospheric pollutants connected to the population growth and industrial development. At the same time the monsoon rainfall trends and patterns have been changed causing serious economic and societal impacts. In this study we have analyzed the link between the aerosols and the monsoon system focusing the attention on a specific mechanism: the Elevated Heat Pump (EHP) hypothesis. According to the EHP the load of dust, organic carbon and black carbon in the pre-monsoon season over the Indo-Gangetic Plain and the foothills of the Himalayas induces enhanced warming in the middle and upper troposphere and changes the convection patterns. As a consequence the rainfall over northern India in late spring and early summer increases and the rainfall in all India in late summer decreases. However, there are still debated conclusions and large uncertainties in this proposed mechanism with ambiguity and uncertainties coming from the lack of real observations and to the consistency of the measurements. By using Historical Natural runs of 3 different Coupled Model Intercomparison Project Phase 5 (CMIP5) models with interactive aerosol loading, we have analysed the variation of precipitation and atmospheric temperature in correspondence to high and low aerosol load years in a time range of 160 years. For deepening the study and validating the model results, we have also included in our analyses the International Satellite Cloud Climatology Project (ISCCP) Deep Convective Tracking Database and the GPS Radio Occultation (RO) measurements. Our preliminary results with models and the two satellite measurements do not show significant evidence of EHP in terms of convection patterns, while the middle and upper troposphere thermal structure is consistent with previous findings.

  7. Assessment of ionospheric Joule heating by GUMICS-4 MHD simulation, AMIE, and satellite-based statistics: towards a synthesis

    Directory of Open Access Journals (Sweden)

    M. Palmroth

    2005-09-01

    Full Text Available We investigate the Northern Hemisphere Joule heating from several observational and computational sources with the purpose of calibrating a previously identified functional dependence between solar wind parameters and ionospheric total energy consumption computed from a global magnetohydrodynamic (MHD simulation (Grand Unified Magnetosphere Ionosphere Coupling Simulation, GUMICS-4. In this paper, the calibration focuses on determining the amount and temporal characteristics of Northern Hemisphere Joule heating. Joule heating during a substorm is estimated from global observations, including electric fields provided by Super Dual Auroral Network (SuperDARN and Pedersen conductances given by the ultraviolet (UV and X-ray imagers on board the Polar satellite. Furthermore, Joule heating is assessed from several activity index proxies, large statistical surveys, assimilative data methods (AMIE, and the global MHD simulation GUMICS-4. We show that the temporal and spatial variation of the Joule heating computed from the GUMICS-4 simulation is consistent with observational and statistical methods. However, the different observational methods do not give a consistent estimate for the magnitude of the global Joule heating. We suggest that multiplying the GUMICS-4 total Joule heating by a factor of 10 approximates the observed Joule heating reasonably well. The lesser amount of Joule heating in GUMICS-4 is essentially caused by weaker Region 2 currents and polar cap potentials. We also show by theoretical arguments that multiplying independent measurements of averaged electric fields and Pedersen conductances yields an overestimation of Joule heating.

    Keywords. Ionosphere (Auroral ionosphere; Modeling and forecasting; Electric fields and currents

  8. Assessment of ionospheric Joule heating by GUMICS-4 MHD simulation, AMIE, and satellite-based statistics: towards a synthesis

    Science.gov (United States)

    Palmroth, M.; Janhunen, P.; Pulkkinen, T. I.; Aksnes, A.; Lu, G.; Østgaard, N.; Watermann, J.; Reeves, G. D.; Germany, G. A.

    2005-09-01

    We investigate the Northern Hemisphere Joule heating from several observational and computational sources with the purpose of calibrating a previously identified functional dependence between solar wind parameters and ionospheric total energy consumption computed from a global magnetohydrodynamic (MHD) simulation (Grand Unified Magnetosphere Ionosphere Coupling Simulation, GUMICS-4). In this paper, the calibration focuses on determining the amount and temporal characteristics of Northern Hemisphere Joule heating. Joule heating during a substorm is estimated from global observations, including electric fields provided by Super Dual Auroral Network (SuperDARN) and Pedersen conductances given by the ultraviolet (UV) and X-ray imagers on board the Polar satellite. Furthermore, Joule heating is assessed from several activity index proxies, large statistical surveys, assimilative data methods (AMIE), and the global MHD simulation GUMICS-4. We show that the temporal and spatial variation of the Joule heating computed from the GUMICS-4 simulation is consistent with observational and statistical methods. However, the different observational methods do not give a consistent estimate for the magnitude of the global Joule heating. We suggest that multiplying the GUMICS-4 total Joule heating by a factor of 10 approximates the observed Joule heating reasonably well. The lesser amount of Joule heating in GUMICS-4 is essentially caused by weaker Region 2 currents and polar cap potentials. We also show by theoretical arguments that multiplying independent measurements of averaged electric fields and Pedersen conductances yields an overestimation of Joule heating. Keywords. Ionosphere (Auroral ionosphere; Modeling and forecasting; Electric fields and currents)

  9. Experimental study of a three-adsorber sorption refrigerator for utilization of renewable sources of energy

    Science.gov (United States)

    Tsitovich, A. P.

    2013-03-01

    A three-adsorber refrigerator has been created and experimentally tested, in which use is made of a composite sorbent consisting of activated carbon fiber and alkali salts. This sorbent has a high capacity of storage of refrigeration characteristic of chemical coolers and a high sorption rate characteristic of adsorption refrigerators. The sorbent structure makes it possible to effect a convective intrapore process of cooling of the sorbent through intense two-phase heat transfer. A three-adsorber refrigerator has a higher refrigeration efficiency and smaller mass and overall dimensions than a traditional two-stage four-adsorber refrigerator.

  10. Non-linear and adaptive control of a refrigeration system

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Larsen, Lars F. S.

    2011-01-01

    In a refrigeration process heat is absorbed in an evaporator by evaporating a flow of liquid refrigerant at low pressure and temperature. Controlling the evaporator inlet valve and the compressor in such a way that a high degree of liquid filling in the evaporator is obtained at all compressor...... are capable of adapting to variety of systems. This paper proposes a novel method for superheat and capacity control of refrigeration systems; namely by controlling the superheat by the compressor speed and capacity by the refrigerant flow. A new low order nonlinear model of the evaporator is developed...

  11. 制冷装置用管壳式换热器清洁度管控研究%The Research of Management and Control the Cleanliness of Shell-and-tube Heat-exchanger Used in Refrigeration Equipment

    Institute of Scientific and Technical Information of China (English)

    周艳彬; 王少军; 杨久子

    2014-01-01

    This paper describes the importance of cleanliness to refrigeration equipment of central air-conditioning. Aiming at the shell-and-tube heat exchanger, it analyzes the pollution resource, and mainly discusses the control method and measurement of the cleanliness level from the perspectives of the design structure, the parts processing, and the shell-and-tube heat exchanger process.%本文讲述了清洁度对于中央空调制冷主机的重要性。针对管壳式换热器,分析了污染杂质来源,并从设计结构、零部件加工和管壳式换热器总成工艺三方面重点讨论其清洁度控制方法和措施。

  12. 重型卡车朗肯-朗肯制冷系统热力学研究%Theoretical Study on the Rankine-Rankine Refrigeration Cycle System Driven by Heavy Truck Waste Heat

    Institute of Scientific and Technical Information of China (English)

    王令宝; 卜宪标; 李华山; 马伟斌

    2014-01-01

    本文针对重型卡车发动机冷却液余热工况,采用R245fa作为循环工质建立了朗肯-朗肯制冷系统,剖析了此系统的基本原理和结构特点,根据系统分析建立了数学模型,模拟分析了发生温度、冷凝温度、蒸发温度对系统性能的影响。结果表明:在发生温度85℃、冷凝温度50℃、蒸发温度5℃时,系统COP达到0.254,虽然此系统的效率要低于相同工况下的吸收制冷循环,但是朗肯-朗肯制冷系统相对于吸收制冷系统具有尺寸小、易于控制和快速响应等优点,利用朗肯-朗肯循环回收重型卡车发动机冷却液余热迚行制冷是可行的。%The paper established a Rankine-Rankine refrigeration cycle system driven by heavy truck engine coolant waste heat, which uses R245fa as working medium. The basic principle and structural characteristics of the system are analyzed. According to the system analysis, the mathematical model is established. The effects of generating temperature, condensation temperature and evaporation temperature on the system performance are investigated. The COP reaches 0.254, when the generating temperature is 85oC, the condensation temperature is 50oC and the evaporation temperature is 5oC. The Rankine-Rankine refrigeration cycle system has the advantages of small size, easy to control and fast response, although the COP is lower than that of the absorption refrigeration under the same condition. We can believe that Rankine-Rankine refrigeration cycle system is feasible to recovery engine coolant waste heat.

  13. 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

  14. Performance of a residential heat pump operating with a non-azeotropic binary refrigerant mixture - an interim report. [R22 vs non-azeotropic binary mixture of R13B1 and R152a

    Energy Technology Data Exchange (ETDEWEB)

    Didion, D.; Mulroy, W.

    1984-01-01

    This report presents results of laboratory measurement of the performance change of a substantially unmodified residential heat pump designed for R22 when charged with a non-azeotropic, binary mixture of R13B1 and R152a. Results are presented for various sizes of fixed expansion devices. The effect of gliding temperature in the saturation zone was found to be small. The effect of composition shift by flash distillation in the accumulator was found to measurably improve low temperature heating performance. There appears to be an inherent trade-off when operating an unmodified heat pump with mixtures so as to increase capacity at lower temperatures. This trade-off is that as the evaporator pressure decreases and refrigerant begins to flood through to the accumulator and thus allowing the composition shift to occur, the subcooling on the high pressure side also decreases causing a decrease in the available latent enthalpy difference. A possible solution to this problem might be to increase the amount of initial charge. This would cause on increase in head pressures which could be a problem in the cooling mode. A possible solution to this excessive head pressure problem would be to incorporate a receiver in the system in the branch line just ahead of the expansion device for the outdoor coil. Thus, when this coil is acting as an evaporator (i.e., heating mode) the stored refrigerant would be released into the circulating system allowing for more composition shift to occur. Such a solution will be pursued as one of the items of study during the next phase of this project. 9 refs., 11 figs., 1 tab.

  15. Ferroelectric Stirling-Cycle Refrigerator

    Science.gov (United States)

    Jalink, Antony, Jr. (Inventor); Hellbaum, Richard F. (Inventor); Rohrbach, Wayne W. (Inventor)

    1999-01-01

    A Stirling-cycle refrigerator has a three-pump configuration and pumping sequence, in which one pump serves as a compressor. one pump serves as an expander, and one pump serves as a displacer. The pumps are ferroelectrically actuated diaphragm pumps which are coordinated by synchronizing the ferroelectric-actuator voltages in such a way that the net effect of the displacer is to reduce the deleterious effect of dead space; that is, to circulate a greater fraction of the working fluid through the heat exchangers than would be possible by use of the compressor and expander alone. In addition. the displacer can be controlled separately to make the flow of working fluid in the heat exchangers turbulent (to increase the rate of transfer of heat at the cost of greater resistance to flow) or laminar (to decrease the resistance to flow at the cost of a lower heat-transfer rate).

  16. Magnetic Refrigeration – an Energy Efficient Technology for the Future

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Smith, Anders; Pryds, Nini

    2009-01-01

    Magnetic refrigeration is an emerging technology that has the potential to significantly reduce the energy consumption in the refrigeration sector. The technology relies on the heating and cooling of magnetic materials upon the application and removal of a magnetic field, respectively....... This magnetocaloric effect is inherent to all magnetic materials, but manifests itself stronger in some materials. The thermodynamically reversible nature of the magnetocaloric effect holds out the promise of a more energy efficient method of refrigeration compared to conventional compressor technology. Coupling...... this with an absence of ozone depleting and greenhouse contributing gasses gives magnetic refrigeration the potential to become an environmentally sustainable technology. The magnetic refrigeration group at Risø DTU aims to demonstrate the technology in a prototype magnetic refrigeration device. Our work spans a wide...

  17. Magnetic Refrigeration – an Energy Efficient Technology for the Future

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Smith, Anders; Pryds, Nini

    2009-01-01

    Magnetic refrigeration is an emerging technology that has the potential to significantly reduce the energy consumption in the refrigeration sector. The technology relies on the heating and cooling of magnetic materials upon the application and removal of a magnetic field, respectively....... This magnetocaloric effect is inherent to all magnetic materials, but manifests itself stronger in some materials. The thermodynamically reversible nature of the magnetocaloric effect holds out the promise of a more energy efficient method of refrigeration compared to conventional compressor technology. Coupling...... this with an absence of ozone depleting and greenhouse contributing gasses gives magnetic refrigeration the potential to become an environmentally sustainable technology. The magnetic refrigeration group at Risø DTU aims to demonstrate the technology in a prototype magnetic refrigeration device. Our work spans a wide...

  18. Study on Dynamic Characteristics of Ammonia Refrigerator System

    Science.gov (United States)

    Nakashima, Minoru; Ikegami, Yasuyuki; Hirao, Yasuhiro; Sudoh, Gaku; Shingoh, Masashi; Uehara, Haruo

    The dynamic characteristics of ammonia refrigerator system are observed when the expansion valve's opening is slightly changed. The refrigerator system is constructed with the reciprocal compressor, the plate type heat exchanger for the condenser and the evaporator, and the expansion valve. A simple simulation model for this refrigerator system is proposed to develop the computer-simulator of this ammonia refrigerator system and those simulation results are compared to above experimental results. For the development of the computer-simulator, simple but useful models, which can represent the dynamic characteristics of the refrigerator, are adopted for each components of the refrigerator system. The simulation shows the overall good agreement with experiment, without the time constant in the variation of the temperature at the evaporator outlet.

  19. Performance Enhancement Technology for the Vapor Compression Refrigeration Cycle

    Science.gov (United States)

    Man'o, Tatsunori

    High efficiency refrigerator have been developed. For energy saving that is concerned with against global warming, performance enhancement of vapor compression refrigerator is required in field of air condition and refrigeration facility. In this paper, a review of recent performance enhancement technologies for the vapor compression refrigeration cycle is presented. This review contains high performance cycles of large sized centrifugal chiller, small to middle sized chiller and packaged air conditioner. Moreover, researches and developments of the refrigeration cycle recovering throttling loss, applications of ejector to boost in compressor suction pressure and to recirculate vapor refrigerant in the evaporator for heat transfer enhancement, and applications of expander to employ expansion work for compression work, are reviewed.

  20. Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Hessell, Edward

    2013-12-31

    The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

  1. Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Hessell, Edward Thomas [Chemtura Corporation, Middlebury, CT (United States)

    2013-12-31

    The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

  2. High-efficient thermochemical sorption refrigeration driven by low-grade thermal energy

    Institute of Scientific and Technical Information of China (English)

    LI TingXian; WANG RuZhu; WANG LiWei

    2009-01-01

    Thermochemical sorption refrigeration powered by low-grade thermal energy is one of the en ergy-saving and environment friendly green refrigeration technologies. The operation principle of sorption refrigeration system is based on the thermal effects of reversible physicochemical reaction processes between sorbents and refrigerants. This paper presents the developing study on the differ ent thermochemical sorption refrigeration cycles, and some representative high-efficient thermo chemical sorption refrigeration cycles were evaluated and analyzed based on the conventional single-effect sorption cycle. These advanced sorption refrigeration cycles mainly include the heat and mass recovery sorption cycle, double-effect sorption cycle, multi-effect sorption cycle, combined douhie-way sorption cycle, and double-effect and double-way sorption cycle with internal heat recovery.Moreover, the developing tendency of the thermochemical sorption refrigeration is also predicted in this paper.

  3. Evaluation of zeotropic refrigerants based on nonlinear relationship between temperature and enthalpy

    Institute of Scientific and Technical Information of China (English)

    ZHAO Li; GAO Pan

    2006-01-01

    In order to evaluate cycling characters of zeotropic refrigerants in air-conditioning operation, and to reveal distribution rules of temperature difference between refrigerants and heat transfer fluids in condenser and evaporator, theoretical researches were carried out based on nonlinear relationship between temperature and enthalpy in period of refrigerants' phase change. Firstly, a phase changing model of refrigerants was built, and refrigerants state parameters were decided in the air-conditioning operation.Secondly, the state equation of refrigerants was applied for computing relationship between temperature and enthalpy, else based on some suppositions, temperature differences between 15 sorts of refrigerants and heat-transfer fluids were gotten too. Through concluding those temperature differences changing in condenser and evaporator, some rules were found. Lastly, after calculating and comparing the additive exergy loss among15 sorts of refrigerants, which resulted from the changing of temperature difference, their cycling characters evaluation were presented.

  4. A Satellite-Derived Climatological Analysis of Urban Heat Island over Shanghai during 2000–2013

    Directory of Open Access Journals (Sweden)

    Weijiao Huang

    2017-06-01

    Full Text Available The urban heat island is generally conducted based on ground observations of air temperature and remotely sensing of land surface temperature (LST. Satellite remotely sensed LST has the advantages of global coverage and consistent periodicity, which overcomes the weakness of ground observations related to sparse distributions and costs. For human related studies and urban climatology, canopy layer urban heat island (CUHI based on air temperatures is extremely important. This study has employed remote sensing methodology to produce monthly CUHI climatology maps during the period 2000–2013, revealing the spatiotemporal characteristics of daytime and nighttime CUHI during this period of rapid urbanization in Shanghai. Using stepwise linear regression, daytime and nighttime air temperatures at the four overpass times of Terra/Aqua were estimated based on time series of Terra/Aqua-MODIS LST and other auxiliary variables including enhanced vegetation index, normalized difference water index, solar zenith angle and distance to coast. The validation results indicate that the models produced an accuracy of 1.6–2.6 °C RMSE for the four overpass times of Terra/Aqua. The models based on Terra LST showed higher accuracy than those based on Aqua LST, and nighttime air temperature estimation had higher accuracy than daytime. The seasonal analysis shows daytime CUHI is strongest in summer and weakest in winter, while nighttime CUHI is weakest in summer and strongest in autumn. The annual mean daytime CUHI during 2000–2013 is 1.0 and 2.2 °C for Terra and Aqua overpass, respectively. The annual mean nighttime CUHI is about 1.0 °C for both Terra and Aqua overpass. The resultant CUHI climatology maps provide a spatiotemporal quantification of CUHI with emphasis on temperature gradients. This study has provided information of relevance to urban planners and environmental managers for assessing and monitoring urban thermal environments which are constantly

  5. ARTI refrigerant database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M.

    1997-02-01

    The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufacturers and those using alterative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on various refrigerants. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.

  6. ARTI refrigerant database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M. [Calm (James M.), Great Falls, VA (United States)

    1998-08-01

    The Refrigerant Database is an information system on alternative refrigerants, associated lubricants, and their use in air conditioning and refrigeration. It consolidates and facilitates access to property, compatibility, environmental, safety, application and other information. It provides corresponding information on older refrigerants, to assist manufactures and those using alternative refrigerants, to make comparisons and determine differences. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included, though some may be added at a later date. The database identifies sources of specific information on many refrigerants including propane, ammonia, water, carbon dioxide, propylene, ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, polyolester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents. They are included to accelerate availability of the information and will be completed or replaced in future updates.

  7. Heat Pump Cycle Performance Analysis and Flammability Study of the CO2/DME Mixture Refrigerant%CO2/DME混合工质热泵循环性能分析及可燃性研究

    Institute of Scientific and Technical Information of China (English)

    刘学武; 覃旭松; 杜永强; 关西文; 陈申

    2015-01-01

    The drying process is energy saving, efficient and environmental friendly. For solving the problem of high pressure in the transcritical CO2 heat pump cycle, the system of a transcritical heat pump drying cycle with an alternative refrigerant CO2/DME for CO2 is proposed. The performance of the system at different mass fractions of CO2 and DME in the mixtures is theoretically calculated and compared to the pure CO2. For the flammability of the DME, the standard test method ASTM E681-09 for concentration limits of flammability of chemicals was made. The results indicated that, at a certain mass ratio of the mixture refrigerant, there is a optimum pressure for the system. At the low concentration of DME, the mixture refrigerant CO2/DME has optimum performance with a mass ratio of 90/10. With the increasing of DME concentration, the COPh deceases slightly and then increases continually. With the mixture refrigerant CO2/DME has a mass ratio of 90/10, the optimized high side pressure of the transcritical CO2/DME decreased by 23 percent verse the pure CO2 heat pump cycle and the heating coefficient of performance (COPh) is increased by about 3.1 percent. DME flammability deceases as the CO2 added. The critical suppression explosion ratio point is reached at a volume ratio (CO2/DME) of 7.2. When the volume ratio larger than the critical point, the mixture refrigerant will not get explosion no matter how much air is added. It can be safely used.%针对跨临界CO2热泵循环压力高的问题,提出了以CO2/DME混合制冷剂替代纯CO2制冷剂的跨临界热泵循环系统。通过理论计算了不同配比下系统循环性能,并与纯CO2工质性能进行对比;为解决DME可燃性问题,实验测试并研究了混合工质爆炸极限。研究结果表明:在确定的混合工质配比下,系统存在最优压力使COPh最大;随DME质量比的增加,系统最优压力下降,而COPh先小幅下降而后持续增加;CO2/DME 质量配比在90

  8. Exergoeconomic Analysis of a Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Durriye Bilge

    2004-01-01

    Full Text Available The exergoeconomic theory is applied to a two stage vapour compression refrigeration cycle. An exergy-aided cost analysis, taking into account pressure drops and heat gain/loss for all of the components in the refrigeration system as well as the pipe connections, has been made. Exergoeconomic factors, showing whether the monetary expenditures mostly originate from capital investment and Operating and Maintenance (O&M costs or from exergy destruction and exergy loss, are found and shown in the form of tables. The true cost of the heat drawn from cold room, which is the product of a refrigeration sytem, has been calculated. In this way, it will be possible to reflect the cost of cold room storage to the market price of the goods completely and precisely.

  9. An adiabatic demagnetization refrigerator for SIRTF

    Science.gov (United States)

    Timbie, P. T.; Bernstein, G. M.; Richards, P. L.

    1989-02-01

    An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the multiband imaging photometer of the Space Infrared Telescope Facility (SIRTF). One such refrigerator has been built which uses a ferric ammonium alum salt pill suspended by nylon threads in a 3-T solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is less than 0.5 microW. The system has a hold time at 0.1K of more than 12 h. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built at a SIRTF prototype to fly on a ballon-borne telescope. It will use a ferromagnetic shield. The possibility of using a high-Tc solenoid-actuated heat switch is also discussed.

  10. Sura heating facility transmissions to the CASSIOPE/e-POP satellite

    Science.gov (United States)

    James, H. G.; Frolov, V. L.; Andreeva, E. S.; Padokhin, A. M.; Siefring, C. L.

    2017-02-01

    Throughout a nighttime pass of the CASSIOPE satellite at an altitude of about 1300 km above the Sura heating facility, transmission of O-mode radiation from Sura to the enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument on CASSIOPE was maintained. Also, during this pass, continuous VHF/UHF transmission from the e-POP Coherent Electromagnetic Radio Tomography radio beacon to three coordinated ground receivers in the Sura vicinity was achieved. Tomography of the VHF/UHF received wave data based on total electron content permitted the two-dimensional distribution of ionospheric ambient electron plasma frequency fpe to be determined in the latitude-altitude space between Sura and CASSIOPE. The foF2 values about 0.1 MHz above the Sura pump frequency of 4.3 MHz were measured by the tomography. We examine the question of whether the observations can be explained on the basis of classic propagation in a smooth ionosphere. Tracing of rays from Sura toward CASSIOPE orbital locations finds most rays reflected away from the topside by the patchy ionospheric structure in bottomside fpe. It is concluded that O-mode ducting in underdense field-aligned irregularities is responsible for maintaining the transionospheric transmission across the 2 min pass. O- to Z-mode "radio-window" conversion in the F region bottomside is not required to explain these data.

  11. Trend Assessment of Spatio-Temporal Change of Tehran Heat Island Using Satellite Images

    Science.gov (United States)

    Saradjian, M. R.; Sherafati, Sh.

    2015-12-01

    Numerous investigations on Urban Heat Island (UHI) show that land cover change is the main factor of increasing Land Surface Temperature (LST) in urban areas, especially conversion of vegetation and bare soil to concrete, asphalt and other man-made structures. On the other hand, other human activities like those which cause to burning fossil fuels, that increase the amount of carbon dioxide, may raise temperature in global scale in comparison with small scales (urban areas). In this study, multiple satellite images with different spatial and temporal resolutions have been used to determine Land Surface Temperature (LST) variability in Tehran metropolitan area. High temporal resolution of AVHRR images have been used as the main data source when investigating temperature variability in the urban area. The analysis shows that UHI appears more significant at afternoon and night hours. But the urban class temperature is almost equal to its surrounding vegetation and bare soil classes at around noon. It also reveals that there is no specific difference in UHI intense during the days throughout the year. However, it can be concluded that in the process of city expansion in years, UHI has been grown both spatially and in magnitude. In order to locate land-cover types and relate them to LST, Thematic Mapper (TM) images have been exploited. The influence of elevation on the LST has also been studied, using digital elevation model derived from SRTM database.

  12. TREND ASSESSMENT OF SPATIO-TEMPORAL CHANGE OF TEHRAN HEAT ISLAND USING SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    M. R. Saradjian

    2015-12-01

    Full Text Available Numerous investigations on Urban Heat Island (UHI show that land cover change is the main factor of increasing Land Surface Temperature (LST in urban areas, especially conversion of vegetation and bare soil to concrete, asphalt and other man-made structures. On the other hand, other human activities like those which cause to burning fossil fuels, that increase the amount of carbon dioxide, may raise temperature in global scale in comparison with small scales (urban areas. In this study, multiple satellite images with different spatial and temporal resolutions have been used to determine Land Surface Temperature (LST variability in Tehran metropolitan area. High temporal resolution of AVHRR images have been used as the main data source when investigating temperature variability in the urban area. The analysis shows that UHI appears more significant at afternoon and night hours. But the urban class temperature is almost equal to its surrounding vegetation and bare soil classes at around noon. It also reveals that there is no specific difference in UHI intense during the days throughout the year. However, it can be concluded that in the process of city expansion in years, UHI has been grown both spatially and in magnitude. In order to locate land-cover types and relate them to LST, Thematic Mapper (TM images have been exploited. The influence of elevation on the LST has also been studied, using digital elevation model derived from SRTM database.

  13. Computer model of the refrigeration system of an ice rink

    Energy Technology Data Exchange (ETDEWEB)

    Teyssedou, G.; Zmeureanu, R. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Giguere, D. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Technology Centre

    2008-07-01

    This paper presented a refrigeration system model of an existing ice rink using a component approach. The chillers, the ice-concrete slab and the controller were the 3 main components used in the simulations which were performed using both open and closed loop systems. The simulated ice rink refrigeration system was based on measurements taken in an existing indoor ice rink located in Montreal, Quebec. Measurements of the refrigeration system included electricity demand; heat flux on the ice sheet; exterior air temperature; ice temperature; return brine temperature; brine temperature at the pump; brine temperature at both evaporator exits; and refrigerant temperature and pressure at the expansion and condenser valve exits. Simulation results and measurements were found to be in good agreement. A computer model of the refrigeration system was developed using the TRNSYS 16 program. The refrigeration system was composed of 2 chillers using refrigerant R-22. The impact of heat recovery from the condensers on the energy demand for sanitary water heating was also estimated. The potential reduction of equivalent carbon dioxide emissions was calculated using the total equivalent warming impact (TEWI) criterion in an effort to estimate the refrigeration impact on global warming. 12 refs., 4 tabs., 12 figs.

  14. OPTIMAL SYSNTHESIS PROCESSES OF LOW-TEMPERATURE CONDENSATION ASSOCIATED OIL GAS PLANT REFRIGERATION SYSTEM

    Directory of Open Access Journals (Sweden)

    O. Ostapenko

    2015-10-01

    Full Text Available Design of modern high-efficient systems is a key priority for the Energy Sector of Ukraine. The cooling technological streams of gas and oil refineries, including air coolers, water cooling and refrigeration systems for specific refrigerants are the objectives of the present study. Improvement of the refrigeration unit with refrigerant separation into fractions is mandatory in order to increase cooling capacity, lowering the boiling point of coolant and increasing the coefficient of target hydrocarbons extraction from the associated gas flow. In this paper it is shown that cooling temperature plays significant role in low-temperature condensation process. Two operation modes for refrigeration unit were proposed: permanent, in which the concentration of the refrigerant mixture does not change and dynamic, in which the concentration of refrigerant mixtures depends on the ambient temperature. Based on the analysis of exergy losses the optimal concentration of refrigerant mixtures propane/ethane for both modes of operation of the refrigeration unit has been determined. On the basis of the conducted pinch-analysis the modification of refrigeration unit with refrigerant separation into fractions was developed. Additional recuperative heat exchangers for utilization heat were added to the scheme. Several important measures to increase the mass flow rate of refrigerant through the second section of the refrigeration centrifugal compressor from 22.5 to 25 kg/s without violating the agreed operational mode of the compressor sections were implemented.

  15. A closed-cycle dilution refrigerator for space applications

    Science.gov (United States)

    Chaudhry, Gunaranjan; Volpe, Angela; Camus, Philippe; Triqueneaux, Sébastien; Vermeulen, Gerard

    2012-10-01

    We discuss the development of a gravity-insensitive dilution refrigerator adapted from the open-cycle refrigerator used for the Planck mission. Since the 3He and 4He components are circulated (the 4He by a fountain-effect pump operating at about 2 K, the 3He by a compressor at room temperature) rather than ejected into space, the lifetime of a closed-cycle refrigerator is not limited by the quantity of 3He and 4He available. In this work, we concentrate on the design and performance of the cold end (counterflow heat exchanger and mixing chamber) of the refrigerator. We discuss the sizing of the heat exchanger and present cooling power measurements. We detail the working of the fountain pump. We also briefly touch upon some practical issues including the choice of a 3He compressor and the pre-cooling requirements for the dilution refrigerator.

  16. Refrigerated Warehouse Demand Response Strategy Guide

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Doug [VaCom Technologies, San Luis Obispo, CA (United States); Castillo, Rafael [VaCom Technologies, San Luis Obispo, CA (United States); Larson, Kyle [VaCom Technologies, San Luis Obispo, CA (United States); Dobbs, Brian [VaCom Technologies, San Luis Obispo, CA (United States); Olsen, Daniel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-11-01

    This guide summarizes demand response measures that can be implemented in refrigerated warehouses. In an appendix, it also addresses related energy efficiency opportunities. Reducing overall grid demand during peak periods and energy consumption has benefits for facility operators, grid operators, utility companies, and society. State wide demand response potential for the refrigerated warehouse sector in California is estimated to be over 22.1 Megawatts. Two categories of demand response strategies are described in this guide: load shifting and load shedding. Load shifting can be accomplished via pre-cooling, capacity limiting, and battery charger load management. Load shedding can be achieved by lighting reduction, demand defrost and defrost termination, infiltration reduction, and shutting down miscellaneous equipment. Estimation of the costs and benefits of demand response participation yields simple payback periods of 2-4 years. To improve demand response performance, it’s suggested to install air curtains and another form of infiltration barrier, such as a rollup door, for the passageways. Further modifications to increase efficiency of the refrigeration unit are also analyzed. A larger condenser can maintain the minimum saturated condensing temperature (SCT) for more hours of the day. Lowering the SCT reduces the compressor lift, which results in an overall increase in refrigeration system capacity and energy efficiency. Another way of saving energy in refrigerated warehouses is eliminating the use of under-floor resistance heaters. A more energy efficient alternative to resistance heaters is to utilize the heat that is being rejected from the condenser through a heat exchanger. These energy efficiency measures improve efficiency either by reducing the required electric energy input for the refrigeration system, by helping to curtail the refrigeration load on the system, or by reducing both the load and required energy input.

  17. Functional Nanomaterials Useful for Magnetic Refrigeration Systems

    Science.gov (United States)

    Aslani, Amir

    Magnetic refrigeration is an emerging energy efficient and environmentally friendly refrigeration technology. The principle of magnetic refrigeration is based on the effect of varying a magnetic field on the temperature change of a magnetocaloric material (refrigerant). By applying a magnetic field, the magnetic moments of a magnetic material tend to align parallel to it, and the thermal energy released in this process heats the material. Reversibly, the magnetic moments become randomly oriented when the magnetic field is removed, and the material cools down. The heating and the cooling of a refrigerant in response to a changing magnetic field is similar to the heating and the cooling of a gaseous medium in response to an adiabatic compression and expansion in a conventional refrigeration system. One requirement to make a practical magnetic refrigerator is to have a large temperature change per unit of applied magnetic field, with sufficiently wide operating temperature. So far, no commercially viable magnetic refrigerator has been built primarily due to the low temperature change of bulk refrigerants, the added burden of hysteresis, and the system's low cooling capacity. The purpose of this dissertation is to explore magnetic refrigeration system. First, the Active Magnetic Regenerator (AMR) system built by Shir et al at the GWU's Institute for Magnetics Research (IMR) is optimized by tuning the heat transfer medium parameters and system's operating conditions. Next, by reviewing literature and works done so far on refrigerants, a number of materials that may be suitable to be used in magnetic refrigeration technology were identified. Theoretical work by Bennett et al showed an enhancement in magnetocaloric effect of magnetic nanoparticles. Research was performed on functional magnetic nanoparticles and their use in magnetic refrigeration technology. Different aspects such as the size, shape, chemical composition, structure and interaction of the nanoparticle with

  18. Performance characteristics of pulse tube refrigerators

    Science.gov (United States)

    Huang, B. J.; Tzeng, T. M.

    In the present study experiments were carried out to investigate the performance characteristics of pulse tube refrigerators. It was found that the cool-down time tc during the transient or start-up period is dominated by the time constant of the pulse tube wall τpt and that the dynamics of a basic pulse tube (BPT) refrigerator approaches that of a first-order system. For steady state operation, the cold-end temperature TL was found to vary with τpt, and the cooling load QL increases monotonically with increasing τpt. This indicates that heat pumped by the gas from the cold to the hot end increases with decreasing hpt (i.e. less energy exchange between the gas and wall). The process of heat storage or release of the pulse tube wall is thus shown to have a negative effect on the performance of a BPT refrigerator. It was thus found experimentally that the gas compression/expansion process inside the pulse tube, which is similar to a Brayton cycle but lies between isothermal and adiabatic, can explain the performance of BPT refrigerators. The present experiment also shows that the performance of a pulse tube refrigerator at transient and steady states is mainly dominated by the time constant of the pulse tube wall τpt.

  19. Experimental study on neon refrigeration system using commercial helium compressor

    Science.gov (United States)

    Ko, Junseok; Kim, Hyobong; Hong, Yong-Ju; Yeom, Hankil; Koh, Deuk-Yong; Park, Seong-Je

    2012-06-01

    In this study, we developed neon refrigeration system using commercial helium compressor which was originally designed for GM cryocooler. We performed this research as precedent study before developing neon refrigeration system for small-scale hydrogen liquefaction system. The developed system is based on precooled Linde-Hampson system with liquid nitrogen as precoolant. Design parameters of heat exchangers are determined from thermodynamic cycle analysis with operating pressure of 2 MPa and 0.4 MPa. Heat exchangers have concentric-tube heat exchanger configuration and orifice is used as Joule- Thomson expansion device. In experiments, pressure, temperature, mass flow rate and compressor input power are measured as charging pressure. With experimental results, the characteristics of heat exchanger, Joule-Thomson expansion and refrigeration effect are discussed. The developed neon refrigeration system shows the lowest temperature of 43.9 K.

  20. 自动复叠制冷系统非共沸混合工质的换热模拟%Heat Transfer Simulation of Non-azeotropic Mixtures Automatic Cascade Refrigeration System

    Institute of Scientific and Technical Information of China (English)

    马冰奇; 陈秋燕; 张俊强

    2015-01-01

    In this paper , the cascade refrigeration system , refrigerant R22 will be replaceed with environmental working medium R410a.The heat transfer of the R410a/R23/R14 in the evaporation temperature of -110℃is sim-ulated by Ansys simulation , the working pairs according to the maximum separation rate are selected .Finnally calcu-late the feasibility of using simulation R410a instead of R22.%本文将复叠式制冷系统中制冷剂R22换成环保工质R410a,并且应用Ansys仿真模拟自动复叠制冷系统的蒸发温度为-110℃时非共沸混合工质R410a/R23/R14的换热情况,筛选出最大分离率对应的工质对及其配比,验证R410a代替R22的可行性。

  1. Experimental Study of Heat and Mass Transfer Enhancement of Absorption Refrigeration by Mechanical Vibration%机械振动强化吸收式制冷传热传质的实验研究

    Institute of Scientific and Technical Information of China (English)

    申江; 邹国文; 王建民; Josephine Lau; 申子奇; 孙欢

    2016-01-01

    Effects of mechanical vibration on the heat and mass transfer process of absorption refrigerating system had been researched in this paper. A performance appraisal test bench was set up, thus an electrodynamics vibration generator was installed on the bottom of the absorption refrigerating machine to add vertical vibration into the system. Enhancement effects of vibration frequencies and amplitude on the heat and mass transfer process of absorption refrigerating machine were analyzed respectively. The results showed that when amplitude was constant, vibration frequencies had a strong effect on enhancement effect; and under the optimum spray volume and same vibration frequency, the enhancement effect of vibration would be reduced with too high or too low vibration amplitude. And in the range of test, frequency ranges for the best enhancement effect was 20-30 Hz, in these conditions, the enhancement effect of heat transfer could be 8%-20%, the enhancement effect of mass transfer could be 10% -25%, and cooling capacity increased by 12% -18%.%本文对机械振动强化吸收式制冷传热传质进行实验研究。搭建了一套综合的性能研究实验台,在吸收式制冷机的底部安装了一个电动振动机,使机组在垂直方向上产生振动,分别对振动频率和振幅两个因素对机组性能强化的效果进行实验分析,得出结论:振幅相同时,振动频率对强化效果的影响较大;而在最佳喷淋量下,频率相同时,振幅太大或太小,振动的强化效果都会下降。且在实验范围内,得到最佳强化效果的频率段为20~30 Hz,此时传热的强化效果可达到8%~20%,传质的强化效果可达到10%~25%,制冷量可提高12%~18%。

  2. Molecular modeling of fluoropropene refrigerants.

    Science.gov (United States)

    Raabe, Gabriele

    2012-05-17

    Different fluoropropenes are currently considered as refrigerants, either as pure compounds or as components in low GWP (global warming potential) refrigerant mixtures. Due to their limited commercial production, experimental data for the thermophysical properties of fluoropropenes and their mixtures are in general rare, which hampers the exploration of their performance in technical applications. In principle, molecular simulation can be used to predict the relevant properties of refrigerants and refrigerant blends, provided that adequate intermolecular potential functions ("force fields") are available. In our earlier work (Raabe, G.; Maginn, E. J., J. Phys. Chem. B2010, 114, 10133-10142), we introduced a transferable force field for fluoropropenes comprising the compounds 3,3,3-trifluoro-1-propene (HFO-1243zf), 2,3,3,3-tetrafluoro-1-propene (HFO-1234yf), and hexafluoro-1-propene (HFO-1216). In this paper, we provide an extension of the force field model to the trans- and cis-1,3,3,3-tetrafluoro-1-propene (HFO-1234ze(E), HFO-1234ze) and the cis-1,2,3,3,3-pentafluoro-1-propene (HFO-1225ye(Z)) as well as revised simulation results for HFO-1216. We present Gibbs ensemble simulation results on the vapor pressures, saturated densities, and heats of vaporization of these compounds in comparison with experimental results. The simulation results show that the force field model enables reliable predictions of the properties of the different fluoropropenes and also reproduces well the differing vapor-liquid coexistence and vapor pressure curve of the cis- and trans-isomers of 1,3,3,3-tetrafluoro-1-propene, HFO-1234ze and HFO-1234ze(E). For these two isomers, we also present molecular dynamics simulation studies on their local structure.

  3. An innovative ecological hybrid refrigeration cycle for high power refrigeration facility

    Directory of Open Access Journals (Sweden)

    Cyklis Piotr

    2015-09-01

    Full Text Available Searching for new refrigerants is one of the most significant scientific problems in refrigeration. There are ecological refrigerants commonly known: H2O and CO2. H2O and CO2 known as natural refrigerants, but they have problems:a high freezing point of H2O and a low triple point of CO2. These problems can be solved by the application of a hybrid sorption-compression refrigeration cycle. The cycle combines the application possibility of H2O in the high temperature sorption stage and the low temperature application of CO2 in the compression stage. This solution gives significant energy savings in comparison with the two-stage compressor cycle and with the one-stage transcritical CO2 cycle. Besides, the sorption cycle may be powered by low temperature waste heat or renewable heat. This is an original idea of the authors. In the paper an analysis of the possible extension of this solution for high capacity industrial refrigeration is presented. The estimated energy savings as well as TEWI (Total Equivalent Warming Impact index for ecological gains are calculated.

  4. 回质回热吸附式制冷循环的热力学分析与方案优选%Thermodynamic analysis of mass and heat recovery adsorption refrigeration cycles and scheme selection

    Institute of Scientific and Technical Information of China (English)

    徐圣知; 王丽伟; 王如竹

    2016-01-01

    吸附式制冷是一种能利用低品位热能的节能环保的制冷方式。在空调工况下,硅胶-水回质回热系统应用最多。为了解在特定工况下选择何种循环能提升系统性能,应用热力学第一与第二定律评价指标分析了基本循环、回质循环、回质回热循环的COP、㶲效率、循环熵产。分析表明,回质循环存在推荐最高热源温度和最优热源温度,回质回热循环存在推荐最低热源温度和最优热源温度。例如对于典型夏季空调工况热源温度90℃、蒸发温度10℃、冷凝温度40℃,回质循环的推荐最高热源温度为93℃,高于实际热源温度90℃,选用回质循环更合适而非回质回热循环。最后,对制冷机组的分析表明给出的方法和推荐工作温度区间能针对实际系统给出方案优选和系统控制的指导性建议。%Adsorption refrigeration is an energy-saving and environmental-friendly refrigerating method, which can utilize low-grade thermal energy. Under air-conditioning working conditions, silica gel-water mass and heat recovery systems are most often used. In order to understand which kind of cycle can improve the performance of the system under specific working conditions, the evaluating indicators of the first and the second laws of thermodynamics were adopted to analyze the COP, the exergetic efficiency and the cycle entropy production of the basic cycle, mass recovery cycle and mass and heat recovery cycle. The analysis showed that only when the heating source temperature was relatively low, the COP of mass recovery cycle was remarkably higher than that of basic cycle. The COP of mass and heat recovery cycle was significantly higher than that of mass recovery cycle only when the heating source temperature was relatively high. Consequently, the mass recovery cycle had its recommended highest heating source temperature and optimum heating source temperature, while the mass and heat recovery

  5. Two-watt, 4-Kelvin closed cycle refrigerator performance

    Science.gov (United States)

    Britcliffe, M.

    1987-01-01

    A 2-watt, 4-K helium refrigerator using the Gifford-McMahon/Joule Thomson cycle is described. The unit features a removable displacer cylinder and high-efficiency, low-pressure drop heat exchangers. These improvements result in a 100 percent increase in cooling power over the existing Deep Space Network system. The effects of the heat exchanger efficiency and Gifford-McMahon expander performance on refrigerator capacity are also discussed.

  6. Absorption refrigeration cycle driven by waste heat using R124-DMAC as working fluids%基于R124-DMAC为工质对的余热吸收式制冷

    Institute of Scientific and Technical Information of China (English)

    李星; 徐士鸣; 李见波

    2015-01-01

    Energy saving and emission reduction technologies for vehicles have been paid more attention in recent years, and it is necessary to investigate how to efficiently recover and utilize the waste heat from vehicle engines to drive automotive air conditioning system. Based on that, a full air-cooled bubble absorption refrigeration test system with 3 kW cooling capacity driven by waste heat, using R124-DMAC as working fluids was designed and built. In the system, engine exhaust gas was simulated by heated air. Operating parameters were tested through changing heat source temperature, chilled water temperature and pump flow rate. The maximum COP of the system could reach 0.54 under the condition of generator temperature 100℃ and evaporating temperature−4℃. Heat source and chilled water temperatures had an important effect on cooling capacity and COP, and this system had good stability. However when evaporating temperature was below 5℃, a rectification unit should be considered in order to improve cooling effects. Additionally, this experiment proved that the air-cooled bubble absorber worked well, providing theoretical support for the refrigeration system driven by waste heat in vehicle air conditioning.%设计并搭建了制冷量为3 kW、以R124-DMAC为工质、采用电热高温空气模拟发动机排气废热的空冷鼓泡吸收制冷实验系统,通过改变热空气进口温度、冷冻水温度和浓溶泵流率测试系统工作参数的变化趋势。实验结果表明,当发生器稀溶液出口温度约为100℃时,蒸发温度为−4℃,系统COP值最大可达到约0.54,而且实验系统稳定性较好;影响系统制冷量和COP值的主要参数是热空气进口温度和冷冻水温度;当蒸发温度低于5℃时,为了提高制冷效果需考虑设置精馏装置。

  7. Copper Oxide Nanoparticles for Advanced Refrigerant Thermophysical Properties: Mathematical Modeling

    Directory of Open Access Journals (Sweden)

    S. A. Fadhilah

    2014-01-01

    Full Text Available In modern days, refrigeration systems are important for industrial and domestic applications. The systems consume more electricity as compared to other appliances. The refrigeration systems have been investigated thoroughly in many ways to reduce the energy consumption. Hence, nanorefrigerant which is one kind of nanofluids has been introduced as a superior properties refrigerant that increased the heat transfer rate in the refrigeration system. Many types of materials could be used as the nanoparticles to be suspended into the conventional refrigerants. In this study, the effect of the suspended copper oxide (CuO nanoparticles into the 1,1,1,2-tetrafluoroethane, R-134a is investigated by using mathematical modeling. The investigation includes the thermal conductivity, dynamic viscosity, and heat transfer rate of the nanorefrigerant in a tube of evaporator. The results show enhanced thermophysical properties of nanorefrigerant compared to the conventional refrigerant. These advanced thermophysical properties increased the heat transfer rate in the tube. The nanorefrigerant could be a potential working fluid to be used in the refrigeration system to increase the heat transfer characteristics and save the energy usage.

  8. Thermoeconomic optimization of subcooled and superheated vapor compression refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Selbas, Resat; Kizilkan, OEnder; Sencan, Arzu [Technical Education Faculty, Department of Mechanical Education, Sueleyman Demirel University, Isparta 32260 (Turkey)

    2006-09-15

    An exergy-based thermoeconomic optimization application is applied to a subcooled and superheated vapor compression refrigeration system. The advantage of using the exergy method of thermoeconomic optimization is that various elements of the system - i.e., condenser, evaporator, subcooling and superheating heat exchangers - can be optimized on their own. The application consists of determining the optimum heat exchanger areas with the corresponding optimum subcooling and superheating temperatures. A cost function is specified for the optimum conditions. All calculations are made for three refrigerants: R22, R134a, and R407c. Thermodynamic properties of refrigerants are formulated using the Artificial Neural Network methodology. (author)

  9. Performance characteristics and optimal analysis of a nonlinear diode refrigerator

    Institute of Scientific and Technical Information of China (English)

    Wang Xiu-Mei; He Ji-Zhou; Liang Hong-Ni

    2011-01-01

    This paper establishes a model of a nonlinear diode refrigerator consisting of two diodes switched in the opposite directions and located in two heat reservoirs with different temperatures. Based on the theory of thermal fluctuations, the expressions of the heat flux absorbed from the heat reservoirs are derived. After the heat leak between the two reservoirs is considered, the cooling rate and the coefficient of performance are obtained analytically. The influence of the heat leak and the temperature ratio on the performance characteristics of the refrigerator is analysed in detail.

  10. Satellite combined heat and power plants and their legal autonomy; Satelliten-BHKW und deren rechtliche Eigenstaendigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Loibl, Helmut [Kanzlei Paluka Sobola Loibl und Partner, Regensburg (Germany). Abt. Erneuerbare Energien

    2014-04-15

    Since the landmark decision by the German Court of Justice concerning the term ''plant'' in the context of biogas plants it should be clear beyond doubt that satellite combined heat and power plants (CHPs) are legally autonomous plants pursuant to Para. 3 No. 1 of the Renewable Energy Law (EEG). What has yet to be finally resolved are the conditions under which satellite CHPs are to be regarded as autonomous. This will be a question of distance on the one hand and of operation autonomy on the other. In the individual case both these factors will have to be assessed from the perspective of an average objective, informed citizen. To the extent that its heat and electricity are being utilised in a meaningful manner, the plant's autonomy will be beyond doubt, at least in operational terms. Regarding the remuneration to be paid for satellite CHPs the only case requiring special consideration is when a CHP falls under the EEG of 2012. In this case Para. 1 Section 1 Sentence 2 EEG provides that the remuneration for the CHP in question is to be calculated as if there was a single overall plant. To the extent that none of the CHPs fall under the EEG of 2012, the ruling remains that there is a separate entitlement to remuneration for each satellite CHP. This also holds in cases where satellite CHPs that were commissioned after 1 January 2012 are relocated. When a satellite CHP is replaced by a new one, the rate and duration of remuneration remain unchanged. However, when a new satellite CHP is added to an existing satellite CHP via a gas collector line it is to be treated according to the decisions of the Federal Court of Justice concerning biogas plant extensions: It falls under the law that applies to the existing CHP and has an entitlement to a new minimum remuneration period, albeit subject to the degression rate provided by the EEG version in question.

  11. Two-stage magnetic refrigerator for astronomical applications with reservoir temperatures above 4 K

    Science.gov (United States)

    Hagmann, C.; Richards, P. L.

    We propose a novel adiabatic demagnetization refrigerator (ADR) to produce temperatures as low as 100 mK starting from a high temperature reservoir between 4 and 8 K. The high temperature reservoir for the ADR can be provided by a mechanical cooler or an unpumped liquid helium bath. This refrigerator can be used to cool bolometric infrared detectors for low background astronomy from mountain tops, balloons or satellites, as well as to cool cryogenic X-ray detectors. The two-stage ADR consists of a single magnet with a paramagnetic chromic caesium alum (CCA) salt pill to produce the low temperature and paramagnetic gadolinium gallium garnet (GGG) as the first stage to intercept heat from the high temperature reservoir. Thermal contact between the paramagnets and the reservoir during magnetization is made with a mechanical heat switch. The ADR is suspended with Kevlar cords under tension for high mechanical stiffness and low parasitic heat leak. In a single cycle, the ADR maintains a temperature of 100 mK for 10-100 h. This time depends strongly on the magnetic field and reservoir temperature but not on the volume of the paramagnetic material as long as the heat leak is dominated by the suspension.

  12. A two-stage magnetic refrigerator for astronomical applications with reservoir temperatures above 4 K

    Science.gov (United States)

    Hagmann, C.; Richards, P. L.

    1993-02-01

    We propose a novel adiabatic demagnetization refrigerator (ADR) to produce temperatures as low as 100 mK starting from a high temperature reservoir between 4 and 8 K. The high temperature reservoir for the ADR can be provided by a mechanical cooler or an unpumped liquid helium bath. This refrigerator can be used to cool bolometric infrared detectors for low background astronomy from mountain tops, balloons or satellites as well as to cool cryogenic x-ray detectors. The two-stage ADR consists of a single magnet with a paramagnetic chromic-cesium-alum (CCA) salt pill to produce the low temperature and paramagnetic gadolinium-gallium-garnet (GGG) as the first stage to intercept heat from the high temperature reservoir. Thermal contact between the paramagnets and the reservoir during magnetization is made with a mechanical heat switch. The ADR is suspended with Kevlar chords under tension for high mechanical stiffness and low parasitic heat leak. In a single cycle, the ADR maintains a temperature of 100 mK for 10 to 100 hours. This time depends strongly on the magnetic field and reservoir temperature but not on the volume of the paramagnetic material as long as the heat leak is dominated by the suspension.

  13. Pulse Tube Refrigerator

    Science.gov (United States)

    Matsubara, Yoichi

    The pulse tube refrigerator is one of the regenerative cycle refrigerators such as Stirling cycle or Gifford-McMahon cycle which gives the cooling temperature below 150 K down to liquid helium temperature. In 1963, W. E. Gifford invented a simple refrigeration cycle which is composed of compressor, regenerator and simple tube named as pulse tube which gives a similar function of the expander in Stirling or Gifford-McMahon cycle. The thermodynamically performance of this pulse tube refrigerator is inferior to that of other regenerative cycles. In 1984, however, Mikulin and coworkers made a significant advance in pulse tube configuration called as orifice pulse tube. After this, several modifications of the pulse tube hot end configuration have been developed. With those modifications, the thermodynamic performance of the pulse tube refrigerator became the same order to that of Stirling and Gifford-McMahon refrigerator. This article reviews the brief history of the pulse tube refrigerator development in the view point of its thermodynamically efficiency. Simplified theories of the energy flow in the pulse tube have also been described.

  14. The toxicity of refrigerants

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M.

    1996-07-01

    This paper presents toxicity data and exposure limits for refrigerants. The data address both acute (short-term, single exposure) and chronic (long-term, repeated exposure) effects, with emphasis on the former. The refrigerants covered include those in common use for the last decade, those used as components in alternatives, and selected candidates for future replacements. The paper also reviews the toxicity indicators used in both safety standards and building, mechanical, and fire codes. It then outlines current classification methods for refrigerant safety and relates them to standard and code usage.

  15. Listeria monocytogenes survival in refrigerator dill pickles.

    Science.gov (United States)

    Kim, Jin Kyung; D'Sa, Elaine M; Harrison, Mark A; Harrison, Judy A; Andress, Elizabeth L

    2005-11-01

    Listeria monocytogenes can survive and grow in refrigerated foods with pH values of approximately 4.0 to 5.0 and salt concentrations of 3 to 4%. Home-fermented refrigerator dill pickles fit this description. Contamination of this product with L. monocytogenes could cause serious problems because these items are not heated prior to consumption. L. monocytogenes survival and growth patterns were investigated in refrigerator dill pickles at 1.3, 3.8, and 7.6% salt concentrations. Pickling cucumbers were dipped into an inoculum of L. monocytogenes, brine mixtures were added, and cucumbers were held at room temperature for 1 week and then refrigerated for up to 3 months. The pH, NaCl percentage, titratable acidity percentage, and total populations of Listeria and aerobic, psychrotrophic, and lactic acid bacteria were measured at the addition of brine, after 2, 4, and 7 days of storage at room temperature, and then weekly during refrigerated storage. The initial Listeria population was 5.4 to 5.6 log CFU/cm2 on cucumber surfaces and 3.9 to 4.6 log CFU/g internally. There was an approximate 0.3- to 1-log increase during room temperature fermentation followed by a population decline during refrigerator storage, with a greater decrease in the brines with the highest NaCl concentration. Up to 49 days, the internal tissue of pickles with 1.3, 3.8, or 7.6% salt concentrations were presumptively positive for L. monocytogenes by the enrichment method, and at 91 days the surfaces of such pickles were still positive for L. monocytogenes. Populations of total aerobes and lactic acid bacteria increased during room temperature storage and decreased gradually during refrigerated storage.

  16. Ecological optimization for an irreversible magnetic Ericsson refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    Wang Hao; Wu Guo-Xing

    2013-01-01

    An irreversible Ericsson refrigeration cycle model is established,in which multi-irreversibilities such as finite-rate heat transfer,regenerative loss,heat leakage,and the efficiency of the regenerator are taken into account.Expressions for several important performance parameters,such as the cooling rate,coefficient of performance (COP),power input,exergy output rate,entropy generation rate,and ecological function are derived.The influences of the heat leakage and the time of the regenerative processes on the ecological performance of the refrigerator are analyzed.The optimal regions of the ecological function,cooling rate,and COP are determined and evaluated.Furthermore,some important parameter relations of the refrigerator are revealed and discussed in detail.The results obtained here have general significance and will be helpful in gaining a deep understanding of the magnetic Ericsson refrigeration cycle.

  17. Evaluation of vapor compression cycles using nonazeotropic refrigerant mixtures

    Science.gov (United States)

    Merriam, Richard L.

    A comprehensive investigation is carried out, on a systematic and consistent basis, to explore a range of advanced heat pump cycle concepts using nonazeotropic refrigerants for COP enhancement and capacity modulation along with the trade-offs associated with refrigerant mixture selection. The objectives of the study were to: identify candidate nonazeotropic mixtures and advanced heat pump cycle concepts with emphasis on their potential for single-speed capacity modulation with mixture composition control; assess the effect of conjunction with nonazeotropic mixture cycles; evaluate the cycles analytically and recommend the most promising cycles and mixtures for further development; and provide recommendations relating to the needs for additional refrigerant property data, experimental studies of basic heat transfer phenomena with mixed refrigerants, development of system components, and/or more detailed modeling of specific components.

  18. 92 K thermoacoustically driven pulse tube refrigerator

    Institute of Scientific and Technical Information of China (English)

    TANG Ke; CHEN Guobang; JIN Tao; KONG Bo; BAO Rui; QIU Limin; GAN Zhihua

    2004-01-01

    @@ A thermoacoustic prime mover, instead of a mechanical compressor, was firstly proposed in 1990 by Radebaugh and Swift et al. to drive a pulse tube refrigerator [1]. The so-called thermoacoustically driven pulse tube refrigerator (TADPTR) has a number of advantages. First,it is characterized by its long-term stable operation for it has no moving components. Besides, solar energy and waste fuel gas can be adopted as its driving source. Utilization of low-grade energy not only improves its overall thermal efficiency, but also is most attractively applicable to the case which is short of electricity but abundant in heat energy. The potential applications, such as thermoacoustic natural gas liquefier, are under development[2].It burns part of natural gas to drive a pulse tube refrigerator whose cooling capacity is then used to liquefy the rest natural gas.

  19. Basics of Low-temperature Refrigeration

    CERN Document Server

    Alekseev, A

    2014-01-01

    This chapter gives an overview of the principles of low temperature refrigeration and the thermodynamics behind it. Basic cryogenic processes - Joule-Thomoson process, Brayton process as well as Claude process - are described and compared. A typical helium laboratory refrigerator based on Claude process is used as a typical example of a low-temperature refrigeration system. A description of the hardware components for helium liquefaction is an important part of this paper, because the design of the main hardware components (compressors, turbines, heat exchangers, pumps, adsorbers, etc.) provides the input for cost calculation, as well as enables to estimate the reliability of the plant and the maintenance expenses. All these numbers are necessary to calculate the economics of a low temperature application.

  20. Characterization of urban heat island effects over Asian megacities with hourly LST maps derived from Japanese geostationary satellite data

    Science.gov (United States)

    Oyoshi, K.; Tamura, M.

    2009-12-01

    Asian countries are expected to continue economic growth with high rate and urban structure can be transformed dramatically. Urbanization and increase in anthropogenic energy consumption cause urban heat island effect. And, Heat island effect increases cooling cost in summer and induces health problem such as heat stroke. Remotely sensed data can be powerful tool to characterize urban area and measure urban thermal conditions, because it is able to capture spatio-temporal variations in urban environments. Japanese geostationary meteorological satellite, MTSAT which covers east Asia and the western Pacific region from 140 degrees East above the equator was launched in February 2005. MTSAT provides hourly visible and thermal infrared image, and hourly Land Surface Temperature (LST) can be retrieved. Therefore, compared to polar orbiting satellites such as MODIS or AVHRR, MTSAT is expected to characterize urban thermal conditions in much detailed temporal scale. In this study, in order to evaluate thermal conditions over Asian megacities with MTSAT data, we investigated methodology for monitoring urban LST with satellite data and characterize thermal conditions by using hourly LST data. Firstly, LST were retrieved from MTSAT thermal infrared data with split-window algorithm, and it was confirmed that MTSAT is able to capture hourly spatio-temporal changes and detect urban heat island effects. Then, we constructed LST database of Asian megacities and the database was open to public on the WWW (http://eiserv.uee.kyoto-u.ac.jp/MTSAT/LST/index_e.php). Finally, by using developed LST database, characteristics of hourly temperature changes of Asian megacities were compared and categorized. And it is found that these characteristics were depend on urban structure of each city. Near-real time land surface temperature (LST) monitoring system on the WWW. Latest LST images of Asian megacities are displayed on the top page.

  1. Flow-synchronous field motion refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Hassen, Charles N.

    2017-08-22

    An improved method to manage the flow of heat in an active regenerator in a magnetocaloric or an electrocaloric heat-pump refrigeration system, in which heat exchange fluid moves synchronously with the motion of a magnetic or electric field. Only a portion of the length of the active regenerator bed is introduced to or removed from the field at one time, and the heat exchange fluid flows from the cold side toward the hot side while the magnetic or electric field moves along the active regenerator bed.

  2. Combined Refrigeration Cycle for Thermal Power Plant Using Low Grade Waste Steam

    Directory of Open Access Journals (Sweden)

    Satish Maurya*,

    2014-02-01

    Full Text Available Now a days, In most of the thermal power plant, where low-pressure steam is being exhausted to the atmosphere as a waste steam. This waste heat could be use to operate many small preheating or cooling equipments or small scale plants. There are many refrigeration systems present for refrigeration and air condition purpose. Such as air refrigeration, vapour compression, vapour absorption etc. In this paper we have presented the concept of combined vapour absorption and vapour compression refrigeration system. We present about the idea discuss here that how a vapour absorption and vapour compression can be used together as one complete working refrigeration plant. By using such concept of refrigeration we can improve the co-efficient of performance of whole plant by minimizing the input. We can also named the system as waste heat recovery refrigeration system.

  3. Performance Characteristics of Vapor Compression Refrigeration Cycle Based on Ericsson Cycle

    Science.gov (United States)

    Ino, Nobumi; Kishi, Takayuki; Nishio, Toshio

    The purpose of this research and investigation is to confirm and clarify the performance characteristics of the vapor compression refrigeration cycle based on the Ericsson Cycle (referred to hereinafter as "this cycle" in this paper). The theoretical analysis and comparison in performance of the conventional refrigeration cycle with this cycle using 12 different but typical refrigerants, produced the following essential and interesting results, i.e., (1) there are conditions for maximizing the COP of this cycle using the expansion valve, (2)both the COP and refrigeration capacity using this cycle showed improvement for all refrigerants other than R717 and R32, (3)the improvement rate for the COP and the refrigeration capacity becomes larger as the specific heat ratio at the gas outlet point of the regenerative heat exchanger becomes smaller, with the rate value differing according to the type of refrigerant.

  4. The Effects of Internal and External Irreversibility of a Vapor Compression Refrigeration Cycle

    Science.gov (United States)

    Wang, Fu-Jen; Chiou, Jeng-Shing

    The concept of finite-time thermodynamics is employed to investigate the optimal refrigeration rate for an irreversible refrigeration cycle. The heat transfer between the system (internal) fluid and cooling (external) fluid takes place at the actual heat exchanger, which has the finite-size heat transfer area and the realistic heat transfer effectiveness. The internal irreversibility results from the compression process and the expansion process are also considered. The optimal refrigeration rate is calculated and expressed in terms of the irreversibility parameter (Ir), coefficient of performance (COP), the time ratio(γ) of heat transfer processes and the effectiveness of heat exchanger. The derived COP which consider both the external and internal irreversibility can thus be considered as the benchmark value for a practical refrigeration cycle, and the parametric study can provide the basis for both determination of optimal operating conditions and design of a practical refrigeration cycle.

  5. Energy conservation in refrigerating machines by combining of thermo-static expansion valve and interior heat transfer material; Energieeinsparung in Kaelteanlagen durch Kombination von thermostatischem Expansionsventil und innerem Waermeuebertrager

    Energy Technology Data Exchange (ETDEWEB)

    Tambovtsev, Alexander

    2007-12-15

    The invention of the refrigerating machine enables to generate cold energy in any needed amount and at any desired temperature. However, cold energy generation requires driving energy. The target of this dissertation is to reduce the energy consumption of refrigerating plants considerably by means of an intelligent combination of the thermo-static expansion valve and the interior heat transfer medium. This combination should not deteriorate the reliability nor incur additional costs. Until today the two known components thermo-static expansion valve and interior heat transfer medium are considered as incompatible, because the simple connection of both components leads to an unstable control behaviour. After a detailed analysis of the causes for this instability the hypothesis is made, a stable working area can be found by means of a deliberate ''deterioration'' of the internal heat transfer medium. This ''deterioration'' can be e.g. a bypass of a part of the high-pressure flow or a parallel flow arrangement of the flows in the heat transfer medium. This hypothesis was primarily proved by experiments, but also by simulation calculations. A test stand was set-up for this purpose, which was used to test various configurations and control strategies. A considerable reduction of the energy consumption compared to conventional arrangements was achieved. (orig.) [German] Die Erfindung der Kaeltemaschine macht es moeglich, dass heute zu beliebiger Zeit Kaelte in benoetigter Menge und gewuenschter Temperatur erzeugt werden kann. Aber fuer die Kaelteerzeugung braucht man Antriebsenergie. Das Ziel dieser Doktorarbeit besteht darin, mit einer intelligenten Kombination von thermostatischem Expansionsventil (TEV) und innerem Waermeuebertrager (IWUe) den Energieverbrauch von Kaelteanlagen deutlich zu verringern, ohne dass dies zu einer Verschlechterung der Zuverlaessigkeit oder wesentlichen Mehrkosten fuehrt. Bis heute gelten die beiden

  6. 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

    exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...... and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... and quantitatively with increasing available total heat transfer area. These optimization results allowed to find a “practical” value of the total heat transfer area, i.e. no benefits can be obtained by increasing the available total heat transfer area above this value since the minimal total exergy loss value...

  7. Public Refrigerated Warehouses

    Data.gov (United States)

    Department of Homeland Security — The International Association of Refrigerated Warehouses (IARW) came into existence in 1891 when a number of conventional warehousemen took on the demands of storing...

  8. Modeling Supermarket Refrigeration Systems with EnergyPlus

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, Therese K [ORNL; Baxter, Van D [ORNL

    2010-01-01

    Supermarket refrigeration capabilities were first added to EnergyPlus in 2004. At that time, it was possible to model a direct expansion (DX) rack system with multiple refrigerated cases. The basic simulation software handles all the building energy uses, typically on a 5 to 10 minute time step throughout the period of interest. The original refrigeration module included the ability to model the sensible and latent interactions between the refrigerated cases and the building HVAC system, along with some basic heat recovery capabilities. Over the last few years, the refrigeration module has been expanded to handle more complex systems, such as secondary loops, shared condensers, cascade condensers, subcoolers, and walk-in coolers exchanging energy with multiple conditioned zones.

  9. Overview of RICOR tactical cryogenic refrigerators for space missions

    Science.gov (United States)

    Riabzev, Sergey; Filis, Avishai; Livni, Dorit; Regev, Itai; Segal, Victor; Gover, Dan

    2016-05-01

    Cryogenic refrigerators represent a significant enabling technology for Earth and Space science enterprises. Many of the space instruments require cryogenic refrigeration to enable the use of advanced detectors to explore a wide range of phenomena from space. RICOR refrigerators involved in various space missions are overviewed in this paper, starting in 1994 with "Clementine" Moon mission, till the latest ExoMars mission launched in 2016. RICOR tactical rotary refrigerators have been incorporated in many space instruments, after passing qualification, life time, thermal management testing and flight acceptance. The tactical to space customization framework includes an extensive characterization and qualification test program to validate reliability, the design of thermal interfacing with a detector, vibration export control, efficient heat dissipation in a vacuum environment, robustness, mounting design, compliance with outgassing requirements and strict performance screening. Current RICOR development is focused on dedicated ultra-long-life, highly reliable, space cryogenic refrigerator based on a Pulse Tube design

  10. PIPER Continuous Adiabatic Demagnetization Refrigerator

    Science.gov (United States)

    Kimball, Mark O.; Shirron, Peter J.; Canavan, Edgar R.; James, Bryan L.; Sampson, Michael A.; Letmate, Richard V.

    2017-01-01

    We report upon the development and testing of a 4-stage adiabatic demagnetization refrigerator (ADR) capable of continuous cooling at 0.100 Kelvin. This cooler is being built to cool the detector array aboard NASA's Primordial Inflation Polarization Explorer (PIPER) observatory. The goal of this balloon mission is to measure the primordial gravitational waves that should exist if the theory of cosmological inflation is correct. At altitude, the ADR will hold the array of transition-edge sensors at 100 mK continuously while periodically rejecting heat to a 1.2 K pumped helium bath. During testing on ground, the array is held at the same temperature but heat is rejected to a 4.2 K helium bath indicating the flexibility in this coolers design.

  11. Anomalous Brownian Refrigerator

    OpenAIRE

    Rana, Shubhashis; Pal, P. S.; Saha, Arnab; Jayannavar, A. M.

    2015-01-01

    We present a detailed study of a Brownian particle driven by Carnot-type refrigerating protocol operating between two thermal baths. Both the underdamped as well as the overdamped limits are investigated. The particle is in a harmonic potential with time-periodic strength that drives the particle cyclically between the baths. Each cycle consists of two isothermal steps at different temperatures and two adiabatic steps connecting them. Besides working as a stochastic refrigerator, it is shown ...

  12. Refrigeration systems and applications

    CERN Document Server

    Dincer, Ibrahim

    2010-01-01

    Refrigeration Systems and Applications, 2nd edition offers a comprehensive treatise that addresses real-life technical and operational problems, enabling the reader to gain an understanding of the fundamental principles and the practical applications of refrigeration technology. New and unique analysis techniques (including exergy as a potential tool), models, correlations, procedures and applications are covered, and recent developments in the field are included - many of which are taken from the author's own research activities in this area. The book also includes so

  13. Refrigerants and heat carrier fluids on a betain basis. A natural solution for preventing environmental, toxicity and corrosion problems in heating and cooling systems; Kaelte- und Waermetraeger auf Betain-Basis. Natuerliche Loesung fuer Umwelt-, Toxizitaets- und Korrosionsprobleme in Heiz- und Kuehlsystemen

    Energy Technology Data Exchange (ETDEWEB)

    Willems, B.P.M.; Jokinen, J.

    2004-05-01

    Toxic liquids and environmental hazards in buildings and industrial plants are accepted less than ever today. So far, technical problems prevented substitution of glycol-based heat carrier fluids by brines or vegetable oils. A new refrigerant on the basis of betain has overcome these problems. (orig.) [German] Fluessigkeitstoxizitaet und Umweltrisiken in Gebaeuden und Industrieanlagen werden immer weniger akzeptiert. Der Ersatz Glykol-basierter Waermetraeger durch Fluessigkeiten auf Salz-Basis oder durch Pflanzenoel scheiterte bislang an technischen Schwierigkeiten. Ein neuerer Kaeltetraeger auf Betain-Basis hat diese Probleme ueberwunden. (orig.)

  14. Effects of Plasma Drag on Low Earth Orbiting Satellites due to Heating of Earth's Atmosphere by Coronal Mass Ejections

    CERN Document Server

    Nwankwo, Victor U J

    2013-01-01

    Solar events, such as coronal mass ejections (CMEs) and solar flares, heat up the upper atmosphere and near-Earth space environment. Due to this heating and expansion of the outer atmosphere by the energetic ultraviolet, X-ray and particles expelled from the sun, the low Earth-Orbiting satellites (LEOS) become vulnerable to an enhanced drag force by the ions and molecules of the expanded atmosphere. Out of various types of perturbations, Earth directed CMEs play the most significant role. They are more frequent and intense during the active (solar maximum) phase of the sun's approximately 11-year cycle. As we are approaching another solar maximum later in 2013, it may be instructive to analyse the effects of the past solar cycles on the orbiting satellites using the archival data of space environment parameters as indicators. In this paper, we compute the plasma drag on a model LEOS due to the atmospheric heating by CMEs and other solar events as a function of the solar parameters. Using the current forecast ...

  15. Components of near-surface energy balance derived from satellite soundings – Part 2: Latent heat flux

    Directory of Open Access Journals (Sweden)

    K. Mallick

    2014-06-01

    Full Text Available This paper introduces a relatively simple method for recovering global fields of latent heat flux. The method focuses on specifying Bowen ratio estimates through exploiting air temperature and vapour pressure measurements obtained from infra-red soundings of the AIRS (Atmospheric Infrared Sounder sensor onboard the NASA-Aqua platform. Through combining these Bowen ratio retrievals with satellite surface net available energy data we have specified estimates of global surface latent heat flux at the 1° by 1° scale. These estimates were evaluated against data from 30 terrestrial tower flux sites covering a broad spectrum of biomes. Taking monthly average 13:30 h data for 2003, this revealed a relatively good agreement between the satellite and tower measurements of latent heat flux, with a pooled root mean square deviation of 79 W m−2, and no significant bias. However, this success partly arose as a product of the under specification of the AIRS Bowen ratio compensating for the under specification of the AIRS net available energy.

  16. Modeling tectonic heat flow and source rock maturity in the Rub' Al-Khali Basin (Saudi Arabia), with the help of GOCE satellite gravity data

    NARCIS (Netherlands)

    Abdul Fattah, R.; Meekes, S.; Bouman, J.; Ebbing, J.; Haagmans, R.

    2014-01-01

    A 3D basin modeling study was carried out to reconstruct the regional heat flow and source rock maturity in the Rub'al-Khali basin. Gravity gradient data from the GOCE satellite were used to model deep structures, such as the Moho interface. Tectonic heat flow was modeled using the GOCE-based Moho i

  17. E-education in Refrigeration Technologies for Students and Technicians in the Workplace

    Science.gov (United States)

    Lenaerts, Marnik; Schreurs, Marc; Reulens, Walter

    2011-01-01

    The demand for broadly educated engineers, installers and service technicians is growing because of the strong growth in refrigeration, air conditioning and heating. The rapid technological evolution makes it impossible for a school or training centre to invest in all HVAC (heating ventilation and air conditioning) and refrigeration fields. It is…

  18. 制冷用水平管降膜蒸发器管束换热特性数值模拟%Numerical Simulation of the Heat Transfer Performance of Horizontal Falling Film Evaporator in the Large Refrigeration Systems

    Institute of Scientific and Technical Information of China (English)

    杨培志; 张营; 李晓

    2015-01-01

    A theoretical thermodynamic model with distributed parameters was developed for simulating the falling film heat transfer performance,and in this model the effect of film breakdown (or dry patch)is considered.In this simulation ,the distribu-tion of dry patch,average falling film factor is obtained,and the effect of the tube bundle layout,refrigerant mass flow rate,tube pitch,the flooded tube row amount is also analyzed.This study is a contribution for the design of horizontal falling film evaporators and promote their application in the field of refrigeration and air conditioning.%采用分布参数法建立水平管降膜蒸发器管束换热模型,模拟计算了水平管降膜蒸发器不同管程布置下换热管干斑分布和平均降膜因子,并进行比较分析;并在下进上出的管程布置形式下研究了制冷剂流量、管间距、满液区排管数对蒸发器换热性能的影响。本文的研究为水平管降膜蒸发器的设计提供理论指导,促进其在制冷空调领域的推广应用。

  19. Characteristics of a Mixed Refrigerant Vapor Compression Cycle

    Science.gov (United States)

    Hihara, Eiji; Muneta, Yoshihiro; Saito, Takamoto

    In comparison with conventional refrigerants, the use of non-azeotropic binary mixtures of refrigerants in vapor compression refrigerating systems can result in extension of the application limits, higher reliability, and savings in power consumption. This paper discusses the high temperature heat pump system performance operating with mixed refrigerants. In order to survey the system performances with various mixtures, six kinds of mixtures are examined : R22-R1l4, R22-R11, R12-R114, R12-R11, R 12-R113, and R22-R12. Thermodynamic properties of the first five mixtures are calculated from the Peng-Robinson equation of state with the mixing rules proposed by Ototake, and R22-R12 mixtures by the BWR type equation of state proposed by Kagawa et al. When counter-flow heat exchangers with large surface areas are used for the evaporator and the condenser, the temperature differences between the refrigerant and the heat sink / source fluids can be reduced, and so the energy waste resulting from irreversible heat trasfer can be reduced. Comparing the mixed refrigerants with the pure ones by fixing the refrigerant temperature at the evaporator inlet and the dewpoint temperature at the condenser, higher coefficients of performance (COP), lower condensing pressures, and lower pressure ratios in the refrigerant compressor can be realized. But the performances of the mixtures with R114 as a less volatile component are not so good. When the heat transfer surface area is not large, the mean temperature difference becomes large. If the dewpoint temperatures at the evaporator and the condenser fixed, the range of composition for the improvement of the COP is restricted.

  20. Nucleate Pool Boiling Heat Transfer Characteristics of Refrigerant/Oil Mixture with Diamond Nanoparticles%含油金刚石纳米制冷剂的核态池沸腾换热特性

    Institute of Scientific and Technical Information of China (English)

    庄大伟; 彭浩; 胡海涛; 丁国良; 朱禹

    2011-01-01

    研究了含油金刚石纳米制冷剂(即由制冷剂R113、润滑油VG68和金刚石纳米颗粒组成的纳米流体)的核态池沸腾换热特性,分析了金刚石纳米颗粒对含油制冷剂核态池沸腾换热的影响.实验中饱和压力为101.3 kPa;热流密度为10~80 kW/m2;纳米油(纳米颗粒和润滑油的混合物)的质量分数为0~5%;在纳米油中金刚石纳米颗粒的质量分数为0~15%.实验结果表明:金刚石纳米颗粒增强了含油制冷剂的池沸腾换热,在测试工况下换热系数最大可增加63.4%,并且增加幅度随纳米油中纳米颗粒质量分数的增加而增加,随纳米油质量分数的降低而增加.开发了含油纳米制冷剂池沸腾换热关联式,关联式预测值与94%的实验数据偏差在±20%以内.%Nucleate pool boiling heat transfer characteristics of refrigerant/oil mixture with diamond nanop-articles were investigated experimentally. The refrigerant is R113 and the oil is VG68. The experimental conditions include a saturation pressure of 101. 3 kPa, heat fluxes from 10 to 80 kW · m-2, nanoparticles concentrations in the nanoparticles/oil suspension from 0 to 15 %, and nanoparticles/oil suspension concentrations from 0 to 5 %. The experimental results indicate that the nucleate pool boiling heat transfer coefficient of R113/oil mixture with diamond nanoparticles is larger than that of R113/oil mixture by maximum of 63. 4% under the present experimental conditions, and the enhancement increases with the increase of nanoparticles concentration in the nanoparticles/oil suspension and decreases with the increase of nanoparticles/oil suspension concentration. A correlation for predicting the nucleate pool boiling heat transfer coefficient of refrigerant/oil mixture with nanoparticles was proposed. The predicted values of the new correlation can agree with 94% of the experimental data of R113/oil mixture with diamond nanoparticles in the present study within the

  1. Miscibility comparison for three refrigerant mixtures and four component refrigerants

    Energy Technology Data Exchange (ETDEWEB)

    Kang, H.M.; Pate, M.B.

    1999-07-01

    Miscibility data were taken and compared for seven different refrigerants when mixed with the same polyol ester (POE) lubricant. Four of the seven refrigerants were single-component refrigerants while three of the refrigerants were mixtures composed of various combinations of the pure refrigerants. The purpose of this research was to investigate the difference in miscibility characteristics between refrigerant mixtures and their respective component refrigerants. The POE lubricant was a penta erythritol mixed-acid type POE which has a viscosity ISO32. The four pure refrigerants were R-32, R-125, R-134a, and R-143a and the three refrigerant mixtures were R-404A, R407C, and R-410A. The miscibility tests were performed in a test facility consisting of a series of miniature test cells submerged in a constant temperature bath. The test cells were constructed to allow for complete visibility of the refrigerant/lubricant mixtures under all test conditions. The tests were performed over a concentration range of 0 to 100% and a temperature range of {minus}40 to 194 F. The miscibility test results for refrigerant mixtures are compared to component refrigerants. In all cases, the refrigerant mixtures appear to have better miscibility than their most immiscible pure component.

  2. 微通道内非共沸混合制冷剂的流动沸腾特性%Investigation on flow boiling heat transfer of non-azeotropic refrigerant mixture in microchannel

    Institute of Scientific and Technical Information of China (English)

    吕凤勇; 马虎根; 何红萍; 齐鲁山

    2012-01-01

    采用了3种不同组分比例的R32/R134a工质在0.86 mm的微通道中进行了传热特性和阻力特性的实验研究,考察了非共沸工质不同组分比例对微通道换热特性的影响。实验结果表明:在组分质量分数比为35%/65%时,核态沸腾在小干度下换热效果最好;干度较大时,组分比例对换热的影响效果降低。在大质量流量下传热阻力效应的影响不再明显。在压降方面,组分比为15%/85%的相对压降最大,其它两种组分的压降较小。%The heat transfer characteristics in microchannel 0.86 mm in diameter for refrigerant mixture R32/R134a with three different mass proportions were studied and the effect of non-azeotropic working media with different mass proportions on heart transfer in the microchannel was investigated.The experiment result showed that when mass proportion was 35%/65%,flow boiling heat transfer was the best at low dryness fraction,while the effect of mass proportion on heat transfer was not obvious at high dryness fraction.Heat transfer resistance effect was not obvious at a high mass flux.Pressure drop was the largest when mass proportion was 15%/85%,and for the other two mass proportions,25%/75% and 35%/65%,pressure drop was relatively smaller.

  3. Foreign Examples of Energy Saving in Refrigerating Machine

    Energy Technology Data Exchange (ETDEWEB)

    Editor [Korea Energy Management Corporation, Yongin (Korea)

    2001-07-01

    Gram A/S Company of Denmark developed the low energy-consuming refrigerator for house, LER200. This refrigerator achieved lots of energy saving through improving insulation and cooling devices. As results from the research for one year and the field-testing for 120 housings, this refrigerator saved energy 70% more than the ordinary refrigerator and 40% more than most energy efficient refrigerators in Danish market. Such a type of household refrigerator consumes less than 0.3kWh of electricity at average for 24 hours. An energy saving refrigerating equipment that had been awarded a prize was established in Albany Port Authority Cold of Western Australia. The energy saving features in this equipment is under-floor heating system using heat recovery, an evaporative condenser, low energy consuming hot gas thawing devices, and computer control system. This is one of the first low temperature refrigerating systems using environment-friendly refrigerant. The refrigerating warehouse, which is located in the south 450km from Peth, has a stock of agricultural products for export. The energy saving characteristics of this project is to be applicable to other equipment and to have possibilities of a great energy saving in the application of refrigerating. Mitsubishi Heavy Industries, LTD and Miratomirai Geothermal Supply have collaborated the project that developed the absorption chiller, which had the same steam-consuming rate (3.9kg/h frozen ton) of the largest capacity (5000 frozen ton) of a steam turbine turbo chiller in the world through reexamining a heat reservoir since 1996. The new absorption chiller has begun to be operated after August 1999. Though actual test after operating, its freezing capacity and efficiency were validated to be more than the design specification. Asakawa sewage disposal plant of Hino in Tokyo Japan established a waste heat recovery system for scrubber water. This system has a heat exchanger to treat hot wastewater and an adsorption chiller to

  4. Application of Cryocoolers to a Vintage Dilution Refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Schmitt, Richard; Smith, Gary; Ruschman, Mark; /Fermilab; Beaty, Jim; /Minnesota U.

    2011-06-06

    A dilution refrigerator is required for 50mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80K and at 4K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

  5. Application of cryocoolers to a vintage dilution refrigerator

    Science.gov (United States)

    Schmitt, Richard L.; Smith, Gary; Ruschman, Mark; Beaty, Jim

    2012-06-01

    A dilution refrigerator is required for 50 mK detector operation of CDMS (Cryogenic Dark Matter Search). Besides shielding the dilution refrigerator itself, the liquid nitrogen shield and liquid helium bath in the refrigerator cool the detector cryostat heat shields and cool electronics, resulting in significant external heat loads at 80 K and at 4 K. An Oxford Instruments Kelvinox 400 has served this role for ten years but required daily transfers of liquid nitrogen and liquid helium. Complicating the cryogen supply is the location 800 meters below ground in an RF shielded, class 10000 clean room at Soudan, MN. Nitrogen and helium re-liquefiers using cryocoolers were installed outside the clean room and continuously condense room temperature gas and return the liquids to the dilution refrigerator through a transfer line. This paper will describe the design, installation, controls and performance of liquefaction systems.

  6. Horizontal dilution refrigerator for use in intense proton beams

    CERN Document Server

    Bywater, J A; Crabb, D G

    1982-01-01

    A fast loading high-power horizontal dilution refrigerator insert has been built for use in the Michigan polarized proton target (PPT V). This PPT will be used in measurements of spin effects in high P/sub perpendicular to / elastic p-p scattering at the Brookhaven AGS. The cooling power is compared with the existing interchangeable /sup 3/He evaporation insert, and with similar dilution refrigerators at CERN and Bonn. The relative merits of these two types of refrigerators in absorbing the heat loads of high intensity beams is discussed.

  7. Automatic control study of the icing research tunnel refrigeration system

    Science.gov (United States)

    Kieffer, Arthur W.; Soeder, Ronald H.

    1991-01-01

    The Icing Research Tunnel (IRT) at the NASA Lewis Research Center is a subsonic, closed-return atmospheric tunnel. The tunnel includes a heat exchanger and a refrigeration plant to achieve the desired air temperature and a spray system to generate the type of icing conditions that would be encountered by aircraft. At the present time, the tunnel air temperature is controlled by manual adjustment of freon refrigerant flow control valves. An upgrade of this facility calls for these control valves to be adjusted by an automatic controller. The digital computer simulation of the IRT refrigeration plant and the automatic controller that was used in the simulation are discussed.

  8. Dynamic simulator of helium refrigeration system; Hemiumu reitoki doteki shumyureta

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimura, H.; Mori, M.; Miyake, A. [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)

    1999-06-07

    The helium refrigerator has various operation modes. Therefore, it is insufficient for developing the refrigerating machine only by the static simulator, which simulates only one design point. It is necessary to carry out the design, which can deal with the change of the operation mode and construction of the appropriate controllability of the system. The construction of the dynamic simulator is required in the reason. This time, the heat exchanger in the helium refrigerator cool-down was unsteadily analyzed, and it was compared with the measured value. (NEDO)

  9. Identifying and monitoring urban heat island in Bucharest using satellite time series and low cost meteorological sensors

    Science.gov (United States)

    Sandric, Ionut; Onose, Diana; Vanau, Gabriel; Ioja, Cristian

    2016-04-01

    The present study is focusing on the identification of urban heat island in Bucharest using both remote sensing products and low cost temperature sensors. The urban heat island in Bucharest was analyzed through a network of sensors located in 56 points (47 inside the administrative boundary of the city, 9 outside) 2009-2011. The network lost progressively its initial density, but was reformed during a new phase, 2013-2015. Time series satellite images from MODIS were intersected with the sensors for both phases. Statistical analysis were conducted to identify the temporal and spatial pattern of extreme temperatures in Bucharest. Several environmental factors like albedou, presence and absence of vegetation were used to fit a regression model between MODIS satellite products sensors in order to upscale the temperatures values recorded by MODIS For Bucharest, an important role for air temperature values in urban environments proved to have the local environmental conditions that leads to differences in air temperature at Bucharest city scale between 3-5 °C (both in the summer and in the winter). The UHI maps shows a good correlation with the presence of green areas. Differences in air temperature between higher tree density areas and isolated trees can reach much higher values, averages over 24 h periods still are in the 3-5 °C range The results have been obtained within the project UCLIMESA (Urban Heat Island Monitoring under Present and Future Climate), ongoing between 2013 and 2015 in the framework of the Programme for Research-DevelopmentInnovation for Space Technology and Advanced Research (STAR), administrated by the Romanian Space Agency Keywords: time series, urban heat island

  10. Autostructurizing solid phase of a refrigerant as a multi-functional low-temperature unit of a cooler

    Energy Technology Data Exchange (ETDEWEB)

    Dvornitsyn, A. [NITKriogenmash, Odessa (Ukraine). Technology Research Institute; Naer, V.; Rozhentsev, A. [Odessa State Academy of Refrigeration (Ukraine)

    2004-08-01

    It has been shown that under certain conditions the solid phase of a refrigerant with a peculiar internal capillary-porous structure can be formed in the working circuit of a refrigerating machine. That solid porous phase does not cease circulation of the refrigerant and possess a unique ability to bring its dimensions and internal structure in correspondence with internal and external heat flows that turns it at once into an auto-adjusted combined 'throttling-heat exchanging' unit of the refrigerating machine. The discovered effect opens a prospect of new advanced technologies developing in the field of refrigeration engineering and cryogenics. (author)

  11. ARTI Refrigerant Database

    Energy Technology Data Exchange (ETDEWEB)

    Cain, J.M. (Calm (James M.), Great Falls, VA (United States))

    1993-04-30

    The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents to accelerate availability of the information and will be completed or replaced in future updates.

  12. Downhole pulse tube refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    Swift, G.; Gardner, D. [Los Alamos National Lab., NM (United States). Condensed Matter and Thermal Physics Group

    1997-12-01

    This report summarizes a preliminary design study to explore the plausibility of using pulse tube refrigeration to cool instruments in a hot down-hole environment. The original motivation was to maintain Dave Reagor`s high-temperature superconducting electronics at 75 K, but the study has evolved to include three target design criteria: cooling at 30 C in a 300 C environment, cooling at 75 K in a 50 C environment, cooling at both 75 K and 30 C in a 250 C environment. These specific temperatures were chosen arbitrarily, as representative of what is possible. The primary goals are low cost, reliability, and small package diameter. Pulse-tube refrigeration is a rapidly growing sub-field of cryogenic refrigeration. The pulse tube refrigerator has recently become the simplest, cheapest, most rugged and reliable low-power cryocooler. The authors expect this technology will be applicable downhole because of the ratio of hot to cold temperatures (in absolute units, such as Kelvin) of interest in deep drilling is comparable to the ratios routinely achieved with cryogenic pulse-tube refrigerators.

  13. ARTI Refrigerant Database

    Energy Technology Data Exchange (ETDEWEB)

    Cain, J.M. [Calm (James M.), Great Falls, VA (United States)

    1993-04-30

    The Refrigerant Database consolidates and facilitates access to information to assist industry in developing equipment using alternative refrigerants. The underlying purpose is to accelerate phase out of chemical compounds of environmental concern. The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air-conditioning and refrigeration equipment. The complete documents are not included. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R-717 (ammonia), ethers, and others as well as azeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents addressing compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. Incomplete citations or abstracts are provided for some documents to accelerate availability of the information and will be completed or replaced in future updates.

  14. Mixed layer heat budget of Kuroshio-Tango Triangle using satellite and ship observations

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Akiyama, M.; Sugimori, Y; Wuwa, J.; Okada, Y; Siripong, A

    Using a three dimensional heat flux model, variation of heat storage in the mixed layer of a triangular oceanic area, embedded in the Kuroshio has been studied for a period of a few days in the month of November, 1983. For the estimation of vertical...

  15. Upper ocean heat budget of western-north Pacific using satellite and ship observations

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Sugimori, Y.; Akiyama, M.

    of the Kuroshio box model, the net surface heat flux for the box is -1.4 x 10@u10@@ watt. Though there is a general view that Kuroshio act as an effective feeder for the surface heat loss for this region in the present case it is found that for 10-days mean period...

  16. Condensation of refrigerants flowing inside smooth and corrugated tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hinton, D.L. [Tennessee State Univ., Nashville, TN (United States); Conklin, J.C.; Vineyard, E.A. [Oak Ridge National Lab., TN (United States)

    1995-07-01

    Because heat exchanger thermal performance has a direct fluence on the overall cycle performance of vapor-compression refrigeration machinery,enhanced heat transfer surfaces are of interest to improve the efficiency of heat pumps and air conditioners. We investigated R-22 and a nonazeotropic refrigerant mixture (NARM) of 75% R-143a and 25% R-124 (by mass) to study their thermal performance in a condenser made of conventional smooth tubes and another condenser made of corrugated, or spirally indented, tubes. We investigated the condensing heat transfer and pressure drop characteristics in an experimental test loop model of a domestic beat pump system employing a variable speed compressor. The refrigerant circulates inside the central tube and the water circulates in the annulus. At refrigerant mass fluxes of approximately 275--300 kg/m{sup 2}s, the measured irreversible pressure drop of the corrugated surface was 23% higher than that of the smooth surface for the R-22. At refrigerant mass fluxes of 350-370 kg/m{sup 2}s, the irreversible pressure drop of the corrugated surface was 36% higher than that of the smooth surface for the NARM. The average heat transfer coefficient for the corrugated surface for R-22 was roughly 40% higher than that for the smooth tube surface at refrigerant mass fluxes of 275--295 kg/m{sup 2}s. The average heat transfer coefficient for the corrugated surface for the NARM was typically 70% higher than that for the smooth tube surface at refrigerant mass fluxes of 340--385 kg/m{sup 2}s.

  17. Pulse tube refrigerator; Parusukan reitoki

    Energy Technology Data Exchange (ETDEWEB)

    Hozumi, Yoshikazu [University of Tsukuba, Tsukuba (Japan); Shiraishi, Masao [Hiroshima University, Hiroshima (Japan)

    1999-06-05

    In the cryogenic field, high temperature superconductivity and research and development of the peripheral technology are popular. Refrigerating machine development of the very low temperature is also one of the results. Research and development are mainly advanced as a refrigerating machine of the center for the aerospace plane installation. There is special and small very low temperature refrigerating machine called 'the pulse tube refrigerating machine' of which the practical application is also recently being attempted for the semiconductor cooling using high temperature superconductivity. At present, the basic research of elucidation of refrigeration phenomenon of pulse tube refrigerating machine and development of high-performance pulse tube refrigerating machine is carried out by experiment in the Ministry of International Trade and Industry Mechanical Engineering Lab., Agency of Industrial Sci. and Technology and numerical simulation in Chiyoda Corp. In this report, the pulse tube refrigerating machine is introduced, and the application in the chemical engineering field is considered. (NEDO)

  18. Exergy Analysis of a Combined Power and Ejector Refrigeration Cycle Driven by Low-temperature Heat Sources%低温热源喷射式发电制冷复合系统的(火用)分析

    Institute of Scientific and Technical Information of China (English)

    郑彬; 翁一武

    2011-01-01

    Exergy analysis was carried out for a novel combined power and ejector refrigeration cycle driven by low-temperature heat sources based on the second law of thermodynamics, while a numerical simulation performed for the system using R600a as the working fluid. Results show that under typical heat source conditions such as the inlet temperature Ths=420 K, mass flow mhs =0.2 kg/s and generating temperature Tg =370 K, the system may produce 2.74 kW of net power output (Wnet), 11. 99 kW of refrigeration output (Qe), with an exergy efficiency ηexergy up to 25.83% and energy utilization efficiency ηu up to 45.34%.The cycle exergy loss mainly occurs in the steam generator and ejector. When Tg increases, both Wnet and ηexergy drop slightly, whereas Qe and ηu show a trend of first increase and then decrease due to the variation of mass flow. The energy utilization efficiency ηu reaches maximum while Tg=370 K.%根据热力学第二定律,对一种新型低温热源喷射式发电制冷复合系统进行了(火用)分析,并以R600a作为工质对系统进行了仿真计算.结果表明:在热源入口温度为420 K、热源热水流量为0.2kg/s、热源蒸发温度为370 K的标准工况下,系统净发电量为2.74 kW,系统制冷量为11.99 kw,系统的(火用)效率达到25.83%,系统能量利用率为45.34%;系统(火用)损失主要发生在蒸汽发生器和喷射器中.在热源蒸发温度提高过程中,系统内部工质流量发生改变,导致系统净发电量和(火用)效率小幅下降,制冷量和能量利用率先增后降.当热源蒸发温度为370 K时,系统能量利用率达到最大值.

  19. ARTI Refrigerant Database

    Energy Technology Data Exchange (ETDEWEB)

    Calm, J.M.

    1992-11-09

    The database provides bibliographic citations and abstracts for publications that may be useful in research and design of air- conditioning and refrigeration equipment. The database identifies sources of specific information on R-32, R-123, R-124, R-125, R-134, R-134a, R-141b, R-142b, R-143a, R-152a, R-245ca, R-290 (propane), R- 717 (ammonia), ethers, and others as well as azeotropic and zeotropic and zeotropic blends of these fluids. It addresses lubricants including alkylbenzene, polyalkylene glycol, ester, and other synthetics as well as mineral oils. It also references documents on compatibility of refrigerants and lubricants with metals, plastics, elastomers, motor insulation, and other materials used in refrigerant circuits. A computerized version is available that includes retrieval software.

  20. Energy efficiency in refrigerated transport

    NARCIS (Netherlands)

    Gerwen, R.J.M. van; Sluis, S.M. van der; Schiphouwer, H.

    1998-01-01

    In refrigerated road transport, 10 to 40 `)/0 of the total energy consumption is related to refrigeration. However, energy consumption and energy efficiency of refrigerated transport equipment is rarely mentioned in the discussions about energy saving, potentials in road transport. Two main approach

  1. Exergy analysis of magnetic refrigeration

    CERN Document Server

    Lucia, Umberto

    2010-01-01

    One of the main challenges of the industry today is to face its impact on global warming considering that the greenhouse effect problem is not be solved completely yet. Magnetic refrigeration represents an environment-safe refrigeration technology. The magnetic refrigeration is analysed using the second law analysis and introducing exergy in order to obtain a model for engineering application.

  2. The vapor compression refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Pannkoke, T.

    1995-11-01

    This article is a review of the basic principles of a cycle widely used to create the refrigeration effect that provides both human comfort and process cooling. While a semantic differentiation often is made for cooling and dehumidifying air for human comfort (air conditioning) and cooling for products and processes (refrigeration), all mechanical cooling applications depend on the previously mentioned refrigeration effect.

  3. Refrigeration Playbook: Natural Refrigerants; Selecting and Designing Energy-Efficient Commercial Refrigeration Systems That Use Low Global Warming Potential Refrigerants

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Caleb [CTA Architects Engineers, Boise, ID (United States); Reis, Chuck [CTA Architects Engineers, Boise, ID (United States); Nelson, Eric [CTA Architects Engineers, Boise, ID (United States); Armer, James [CTA Architects Engineers, Boise, ID (United States); Arthur, Rob [CTA Architects Engineers, Boise, ID (United States); Heath, Richard [CTA Architects Engineers, Boise, ID (United States); Rono, James [CTA Architects Engineers, Boise, ID (United States); Hirsch, Adam [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Doebber, Ian [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    This report provides guidance for selecting and designing energy efficient commercial refrigeration systems using low global warming potential refrigerants. Refrigeration systems are generally the largest energy end use in a supermarket type building, often accounting for more than half of a building's energy consumption.

  4. Designing a magnet for magnetic refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerk, R.

    2010-03-15

    This thesis investigates the design and optimization of a permanent magnet assembly for use in a magnetic refrigeration device. The heart of magnetic refrigeration is the adiabatic temperature change in the magnetocaloric material which is caused by the magnetic field. In order to design an ideal magnet assembly the magnetocaloric materials and the refrigeration process itself and their properties and performance as a function of magnetic field are investigated. For the magnetocaloric materials it is the magnetization, specific heat capacity and adiabatic temperature that are investigated as functions of the magnetic field. Following this the process utilized by a magnetic refrigerator to provide cooling is investigated using a publicly available one dimensional numerical model. This process is called active magnetic regeneration (AMR). The aim is to determine the performance of the AMR as a function of the magnetic field in order to learn the properties of the optimal magnet assembly. The performance of the AMR as a function of the synchronization and width of the magnetic field with respect to the AMR cycle, the ramp rate and maximum value of the magnetic field are investigated. Other published magnet designs used in magnetic refrigeration devices are also evaluated, using a figure of merit based on the properties of the investigated magnetocaloric materials, to learn the properties of the best magnet designs to date. Following this investigation the Halbach cylinder, which is a hollow permanent magnet cylinder with a rotating remanent flux density, is investigated in detail as it forms the basis of many magnet designs used in magnetic refrigeration. Here the optimal dimensions of a Halbach cylinder, as well as analytical calculations of the magnetic field for a Halbach cylinder of infinite length, are presented. Once it has been determined which properties are desirable for a magnet used in magnetic refrigeration the design of a new magnet is described. This is

  5. Portable refrigerant charge meter and method for determining the actual refrigerant charge in HVAC systems

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Zhiming; Abdelaziz, Omar; LaClair, Tim L.

    2017-08-08

    A refrigerant charge meter and a method for determining the actual refrigerant charge in HVAC systems are described. The meter includes means for determining an optimum refrigerant charge from system subcooling and system component parameters. The meter also includes means for determining the ratio of the actual refrigerant charge to the optimum refrigerant charge. Finally, the meter includes means for determining the actual refrigerant charge from the optimum refrigerant charge and the ratio of the actual refrigerant charge to the optimum refrigerant charge.

  6. Quantum-enhanced absorption refrigerators

    CERN Document Server

    Correa, Luis A; Alonso, Daniel; Adesso, Gerardo

    2014-01-01

    Thermodynamics is a branch of science blessed by an unparalleled combination of generality of scope and formal simplicity. Based on few natural assumptions together with the four laws, it sets the boundaries between possible and impossible in macroscopic aggregates of matter. This triggered groundbreaking achievements in physics, chemistry and engineering over the last two centuries. Close analogues of those fundamental laws are now being established at the level of individual quantum systems, thus placing limits on the operation of quantum-mechanical devices. Here we study quantum absorption refrigerators, which are driven by heat rather than external work. We establish thermodynamic performance bounds for these machines and investigate their quantum origin. We also show how those bounds may be pushed beyond what is classically achievable, by suitably tailoring the environmental fluctuations via quantum reservoir engineering techniques. Such superefficient quantum-enhanced cooling realises a promising step t...

  7. Phase change stores heat. Use of new fluids as a heat transfer medium in air conditioning and refrigeration technology; Phasenuebergang speichert Waerme. Neue Fluide als Waermetraeger in der Klima- und Kaeltetechnologie einsetzen

    Energy Technology Data Exchange (ETDEWEB)

    Hirn, Gerhard

    2012-07-01

    When it comes to transporting heat from boilers to heating surfaces or supplying cooling energy to cooling ceilings, water has proved to be an excellent heat transfer medium. However, in some application areas it is now facing competition: various research groups are working on heat transfer fluids that have at least double the energy density. Phase change materials such as paraffin, which are finely distributed in water, store heat when they melt and release it again when they solidify.

  8. General performance characteristics of an irreversible ferromagnetic Stirling refrigeration cycle

    NARCIS (Netherlands)

    Lin, G.; Bruck, E.H.; Tegus, O.; Zhang, L.

    2004-01-01

    A new magnetic-refrigeration-cycle model using ferromagnetic materials as a cyclic working substance is set up, in which finite-rate heat transfer, heat leak and regeneration time are taken into account. On the basis of the thermodynamic properties of a ferromagnetic material, the general performanc

  9. Stirling cycle engine and refrigeration systems

    Science.gov (United States)

    Higa, W. H. (Inventor)

    1976-01-01

    A Stirling cycle heat engine is disclosed in which displacer motion is controlled as a function of the working fluid pressure P sub 1 and a substantially constant pressure P sub 0. The heat engine includes an auxiliary chamber at the constant pressure P sub 0. An end surface of a displacer piston is disposed in the auxiliary chamber. During the compression portion of the engine cycle when P sub 1 rises above P sub 0 the displacer forces the working fluid to pass from the cold chamber to the hot chamber of the engine. During the expansion portion of the engine cycle the heated working fluid in the hot chamber does work by pushing down on the engine's drive piston. As the working fluid pressure P sub 1 drops below P sub 0 the displacer forces most of the working fluid in the hot chamber to pass through the regenerator to the cold chamber. The engine is easily combinable with a refrigeration section to provide a refrigeration system in which the engine's single drive piston serves both the engine and the refrigeration section.

  10. Active magnetic refrigerants based on Gd-Si-Ge material and refrigeration apparatus and process

    Science.gov (United States)

    Gschneidner, Jr., Karl A.; Pecharsky, Vitalij K.

    1998-04-28

    Active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or less than 0.5, as a magnetic refrigerant that exhibits a reversible ferromagnetic/antiferromagnetic or ferromagnetic-II/ferromagnetic-I first order phase transition and extraordinary magneto-thermal properties, such as a giant magnetocaloric effect, that renders the refrigerant more efficient and useful than existing magnetic refrigerants for commercialization of magnetic regenerators. The reversible first order phase transition is tunable from approximately 30 K to approximately 290 K (near room temperature) and above by compositional adjustments. The active magnetic regenerator and method can function for refrigerating, air conditioning, and liquefying low temperature cryogens with significantly improved efficiency and operating temperature range from approximately 10 K to 300 K and above. Also an active magnetic regenerator and method using Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4, where x is equal to or greater than 0.5, as a magnetic heater/refrigerant that exhibits a reversible ferromagnetic/paramagnetic second order phase transition with large magneto-thermal properties, such as a large magnetocaloric effect that permits the commercialization of a magnetic heat pump and/or refrigerant. This second order phase transition is tunable from approximately 280 K (near room temperature) to approximately 350 K by composition adjustments. The active magnetic regenerator and method can function for low level heating for climate control for buildings, homes and automobile, and chemical processing.

  11. Refrigerating machine operating characteristics under various mixed refrigerant mass charges

    Energy Technology Data Exchange (ETDEWEB)

    Rozhentsev, Andrey [Far Eastern State Transport University of the Russian Federation, Seryshev street, 47, 680021 Khabarovsk (Russian Federation)

    2008-11-15

    This paper reports the results of experimental investigation of a low-temperature Joule-Thomson refrigerating machine, working by use of a non-azeotropic mixture of refrigerants and with a single-stage hermetic compressor. The temperature, hydraulic and power performance of the machine are determined experimentally in relation to the mixed refrigerant (MR) mass charge. Variations of the MR refrigerating machine operating performance with the working mixture mass charge are found to be considerably different from the analogous performance variations of a refrigerating machine charged with a pure refrigerant. The peculiarities of those relationships are analyzed theoretically. The specific value of a minimum acceptable MR mass charge for the investigated system and its correlation with internal processes in the machine loop are established as well. If the refrigerant mixture mass charges are below the minimum ones, the temperature and power performance of the MR machine differ essentially from the design performance and such operating modes are considered inadmissible. (author)

  12. Investigations on a Thermoacoustic Refrigerator

    CERN Document Server

    Dhuley, Ram C

    2016-01-01

    Thermoacoustic Refrigerators use acoustic power for generating cold temperatures. Development of refrigerators based on the thermoacoustic technology is a novel solution to the present day need of cooling, without causing environmental hazards. With added advantages such as minimal moving parts and absence of CFC refrigerants, these devices can attain low temperatures maintaining a compact size. The present work describes an in-depth theoretical analysis of standing wave thermoacoustic refrigerators. This consists of detailed parametric studies, transient state analysis, and a design using an available simulation software. Design and construction of a thermoacoustic refrigerator using a commercially available electro-dynamic motor is also presented.

  13. Dimensioning of flanged heat exchangers using the CYRANO software: pure refrigerants and mixtures; Dimensionnement des batteries a ailettes a l`aide du logiciel CYRANO: frigorigenes purs et melanges

    Energy Technology Data Exchange (ETDEWEB)

    Bensafi, A.; Borg, S. [CETIAT, Centre Technique des Industries Aerauliques et Thermiques, 69 - Villeurbanne (France)

    1997-12-31

    A software for the dimensioning and simulation of flanged heat exchangers is presented. This software divides the exchanger into pipe sections in which local values of physical properties of fluids and thermal exchange coefficients are used, and for which individual thermal-hydraulic performances are determined. CYRANO can be used for condensers, evaporators and monophase exchanges, with refrigerants like water, R22, R134a and R32/R125/R134a mixtures. The software can be used also in the case of specified complex circuits, equipped with smooth or grooved pipes and with smooth continuous, corrugated or slatted flanges with non-homogeneous air temperature and velocity distributions. The validation of CYRANO was performed on 7 exchangers with and without humidity condensation on the flanges. Comparisons with test results show that the average of errors in exchanged powers is of about 5%, and of about 30% in the case of internal pressure drops. Some simulations of exchangers with HFC mixtures are also presented. (J.S.) 34 refs.

  14. Visualized design on double -effect LiBr- H2O refrigerator driven by waste heat cloud%烟气型双效溴化锂制冷机的可视化设计

    Institute of Scientific and Technical Information of China (English)

    吴永飞; 沈致和

    2012-01-01

    According to related thermal properties models of LiBr - H2O, a numerical method which can ascertain the tem perature of LiBr - H2O based on its enthalpy and concentration was put forward. Moreover, a visualized design program for the double - effect LiBr - H2O refrigerator driven by waste heat cloud was developed. This program provided a convenient and fast so lution for engineering design.%根据溴化锂水溶液的相关物性计算模型,提出了当已知溴化锂溶液比焓和浓度时求其温度的计算机解法,并针对烟气型双效并联溴化锂吸收式制冷机组,利用Visual Basic面向对象的编程技术编制了其可视化设计程序,为工程上设计计算提供了一种高效、快捷的解决方法.

  15. 新型建筑制冷采暖热水一体化系统及模型分析%New Integrated Solar System of Refrigeration and Heating with Hot Water for Building and Model Analysis

    Institute of Scientific and Technical Information of China (English)

    山石泉; 李媛

    2016-01-01

    立足于节能减排的大背景,提出一种新型的制冷采暖热水一体化系统。基于 DeST 软件平台模拟的气象数据,通过建立系统各个模块的模型对系统的节能性、经济性以及 CO2减排性进行了分析,结果表明一体化系统有显著的节能及环保性。如果能大规模使用,会有可观的经济与社会效益。%Based on the background of energy saving and emission reduction, a new type of integrat-ed solar system for refrigeration and heating with hot water is proposed. Based on the meteorological data from DeST software simulation platform, the energy saving, economy and CO2 emission reduction of the sys-tem is analyzed by establishing the system model of the various parts of the system. The results show that the integrated system has obvious energy saving property and environmental protection property. If it can be used on a large scale, there will be considerable economic and social benefits.

  16. Field testing of high-efficiency supermarket refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D. (Foster-Miller, Inc., Waltham, MA (United States))

    1992-12-01

    The Electric Power Research Institute (EPRI) has undertaken a field test to quantify the performance of high-efficiency supermarket refrigeration. The initial work on this project was presented in EPRI report CU-6268 Supermarket Refrigeration Modeling and Field Demonstration.'' The information given here was generated through continued testing at the field test site. The field test was conducted at a supermarket owned by Safeway Stores, Inc., that was located in Menlo Park, CA. Testing was performed with the existing conventional refrigeration system and a high-efficiency multiplex refrigeration system that was installed for these tests. The results of the testing showed that the high-efficiency multiplex system reduced refrigeration energy consumption by 23.9% and peak electric demand for refrigeration by 30.0%. Analyses of these savings showed that the largest portion was due to the use of high-efficiency compressors (29.5% of total saving). Floating head pressure control, ambient and mechanical subcooling, compressor multiplexing and hot gas defrost accounted for 50% of total savings. The remainder of the savings (20.5%) were attributed to the use of an evaporative condenser. Tests were also conducted with several retrofit technologies. The most promising results were obtained with external liquid-suction heat exchangers installed at the outlets of the display cases. Favorable paybacks were calculated for these exchangers when they were used with very low and low temperature refrigeration.

  17. Neon turbo-Brayton cycle refrigerator for HTS power machines

    Science.gov (United States)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  18. Fundamentals of Refrigeration.

    Science.gov (United States)

    Sutliff, Ronald D.; And Others

    This self-study course is designed to familiarize Marine enlisted personnel with the principles of the refrigeration process. The course contains five study units. Each study unit begins with a general objective, which is a statement of what the student should learn from the unit. The study units are divided into numbered work units, each…

  19. Data use investigations for applications Explorer Mission A (Heat Capacity Mapping Mission): HCMM's role in studies of the urban heat island, Great Lakes thermal phenomena and radiometric calibration of satellite data. [Buffalo, Syracuse, and Rochester New York and Lake Ontario

    Science.gov (United States)

    Schott, J. R. (Principal Investigator); Schimminger, E. W.

    1981-01-01

    The utility of data from NASA'a heat capacity mapping mission satellite for studies of the urban heat island, thermal phenomena in large lakes and radiometric calibration of satellite sensors was assessed. The data were found to be of significant value in all cases. Using HCMM data, the existence and microstructure of the heat island can be observed and associated with land cover within the urban complex. The formation and development of the thermal bar in the Great Lakes can be observed and quantitatively mapped using HCMM data. In addition, the thermal patterns observed can be associated with water quality variations observed both from other remote sensing platforms and in situ. The imaging radiometer on-board the HCMM satellite is shown to be calibratible to within about 1.1 C of actual surface temperatures. These findings, as well as the analytical procedures used in studying the HCMM data, are included.

  20. Indirect refrigeration systems with natural refrigerants

    DEFF Research Database (Denmark)

    Knudsen, Hans Jørgen Høgaard; Christensen, Kim Gardø; Jensen, Per Henrik

    1998-01-01

    Heat transfer for boiling and condensing carbon dioxide has been investigated.Heat transfer for carbon dioxide evaporating inside pipe has been measured and compared with Shah's correlation. The measured heat transfer coefficient is much higher than the value determined with the correlation.A shell...

  1. Performance characteristic of a Stirling refrigeration cycle in micro/nano scale

    Science.gov (United States)

    Nie, Wenjie; He, Jizhou; Du, Jianqiang

    2009-02-01

    The aim of the paper is to present the performance characteristics of a Stirling refrigeration cycle in micro/nano scale, in which the working substance of cycle is an ideal Maxwellian gas. Due to the quantum boundary effect on the gas particles confined in the finite domain, the cycle no longer possesses the condition of perfect regeneration. The inherent regenerative losses, the refrigeration heat and coefficient of performance (COP) of the cycle are derived. It is found that, for the micro/nano scaled Stirling refrigeration cycle devices, the refrigeration heat and COP of cycle all depend on the surface area of the system (boundary of cycle) besides the temperature of the heat reservoirs, the volume of system and other parameters, while for the macro scaled refrigeration cycle devices, the refrigeration heat and COP of cycle are independent of the surface area of the system. Variations of the refrigeration heat ratio rR and the COP ratio rε with the temperature ratio τ and volume ratio rV for the different surface area ratio rA are examined, which reveals the influence of the boundary of cycle on the performance of a micro/nano scaled Stirling refrigeration cycle. The results are useful for designing of a micro/nano scaled Stirling cycle device and may conduce to confirming experimentally the quantum boundary effect in the micro/nano scaled devices.

  2. Optimal low symmetric dissipation Carnot engines and refrigerators.

    Science.gov (United States)

    de Tomás, C; Hernández, A Calvo; Roco, J M M

    2012-01-01

    A unified optimization criterion for Carnot engines and refrigerators is proposed. It consists of maximizing the product of the heat absorbed by the working system times the efficiency per unit time of the device, either the engine or the refrigerator. This criterion can be applied to both low symmetric dissipation Carnot engines and refrigerators. For engines the criterion coincides with the maximum power criterion and then the Curzon-Ahlborn efficiency η(CA)=1-√T(c)/T(h) is recovered, where T(h) and T(c) are the temperatures of the hot and cold reservoirs, respectively [Esposito, Kawai, Lindenberg, and Van den Broeck, Phys. Rev. Lett. 105, 150603 (2010)]. For refrigerators the criterion provides the counterpart of Curzon-Ahlborn efficiency for refrigerators ε(CA)=[1/(√1-(T(c)/T(h))]-1, first derived by Yan and Chen for the particular case of an endoreversible Carnot-type refrigerator with linear (Newtonian) finite heat transfer laws [Yan and Chen, J. Phys. D: Appl. Phys. 23, 136 (1990)].

  3. Satellite-Observed Urbanization Characters in Shanghai, China: Aerosols, Urban Heat Island Effect, and Land–Atmosphere Interactions

    Directory of Open Access Journals (Sweden)

    Gary Pereira

    2011-01-01

    Full Text Available Urbanization reflects how human-activities affect natural climate system. Accurately assessing the urban system by comparing it with the nearby rural regions helps to identify the impacts of urbanization. This work uses the recent satellite observed aerosol, skin temperature, land cover, albedo, cloud fraction and water vapor measurements to reveal how the city of Shanghai, one of the biggest, dense urban areas in East Asia, affects land surface and atmosphere conditions. In addition, the National Aeronautics and Space Administration (NASA ground observations from AErosol RObotic NETwork (AERONET is also used to reveal diurnal, seasonal, and interannual variations of the heavy aerosol load over Shanghai region. Furthermore, Shanghai reduces surface albedo, total column water vapor, cloud fraction and increases land skin temperature than rural region. These observations prove that Shanghai significantly modifies local and regional land surface physical properties as well as physical processes, which lead to the urban heat island effect (UHI.

  4. Mathematical model of an air-filled alpha stirling refrigerator

    Science.gov (United States)

    McFarlane, Patrick; Semperlotti, Fabio; Sen, Mihir

    2013-10-01

    This work develops a mathematical model for an alpha Stirling refrigerator with air as the working fluid and will be useful in optimizing the mechanical design of these machines. Two pistons cyclically compress and expand air while moving sinusoidally in separate chambers connected by a regenerator, thus creating a temperature difference across the system. A complete non-linear mathematical model of the machine, including air thermodynamics, and heat transfer from the walls, as well as heat transfer and fluid resistance in the regenerator, is developed. Non-dimensional groups are derived, and the mathematical model is numerically solved. The heat transfer and work are found for both chambers, and the coefficient of performance of each chamber is calculated. Important design parameters are varied and their effect on refrigerator performance determined. This sensitivity analysis, which shows what the significant parameters are, is a useful tool for the design of practical Stirling refrigeration systems.

  5. World's first ejector cycle for mobile refrigerators to stop global warming

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Hirotsugu [Denso Corporation, Kariya (Japan); Gyoeroeg, Tibor [DENSO AUTOMOTIVE Deutschland GmbH, Eching (Germany)

    2010-07-01

    The development of energy-saving technologies is in great demand recently to stop global warming. We are committed to developing the Ejector Cycle as an energy-saving technology for refrigerators and air conditioners. The ejector, which is an energy-saving technological innovation, improves the efficiency of the refrigeration cycle by effectively using the expansion energy that is lost in the conventional vapor-compression cycle, and is applicable to almost all vapor-compression refrigerating air conditioners, thus improving the efficiency of the refrigeration cycle. Concerning the application of the Ejector Cycle in truck-transport refrigerators, we released Ejector Cycle products for large and medium-size freezer trucks, which have been favorably accepted by customers in 2003. Simultaneously we also developed the domestic water supply system using heat pump with natural refrigerant (CO{sub 2}). We developed a new Ejector Cycle, completed in 2007 a cool box which uses the refrigeration cycle of the mobile air-conditioning system to cool drinks and the commercial compact refrigerator. In 2008 a domestic water supply heat pump system using a heat pump with the natural refrigerant CO{sub 2} and the next-generation Ejector Cycle II that substantially improves performance was brought to the market. A new generation of Ejector Cycle is under development which will significantly improve the efficiency of mobile air conditioning systems (orig.)

  6. An overview of adsorptive processes in refrigeration systems

    Directory of Open Access Journals (Sweden)

    Wolak Eliza

    2016-01-01

    Full Text Available Economic reasons and quest for new solutions based on recovering the energy have provoked an increase of interest in the adsorption technology in the refrigeration industry. The confirmation can be the fact that number of published research is on rise. Adsorption appliances may turn out to be an alternative to compression-type coolers. They use ecological chemical agents instead of substances which are aggressive and harmful to the environment. For regeneration of adsorptive refrigeration systems one can use cheap energy in a form of: industrial waste heat, energy of solar radiation and cheap electric power. The paper presents principles of operation as well as advantages and disadvantages of adsorptive refrigeration systems. Basing on literature the most frequently used adsorbent – adsorbate systems – which are employed in refrigeration industry – have been characterized. A review of construction solutions of systems on both laboratory and industrial scale has been made.

  7. 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.

  8. Transitions between refrigeration regions in extremely short quantum cycles

    Science.gov (United States)

    Feldmann, Tova; Kosloff, Ronnie

    2016-05-01

    The relation between the geometry of refrigeration cycles and their performance is explored. The model studied is based on a coupled spin system. Small cycle times, termed sudden refrigerators, develop coherence and inner friction. We explore the interplay between coherence and energy of the working medium employing a family of sudden cycles with decreasing cycle times. At the point of maximum coherence the cycle changes geometry. This region of cycle times is characterized by a dissipative resonance where heat is dissipated both to the hot and cold baths. We rationalize the change of geometry of the cycle as a result of a half-integer quantization which maximizes coherence. From this point on, increasing or decreasing the cycle time, eventually leads to refrigeration cycles. The transition point between refrigerators and short circuit cycles is characterized by a transition from finite to singular dynamical temperature. Extremely short cycle times reach a universal limit where all cycles types are equivalent.

  9. A Dynamic Model of a Vapor Compression Refrigeration Cycle

    Science.gov (United States)

    Yasuda, Hiromu; Yanagisawa, Tetsuji; Izushi, Minetoshi

    A dynamic model of a vapor compression refrigeration cycle composed of a compressor with a high-pressure chamber, cross finned heat exchangers, an expansion valve and pipes is developed. In order to prove the effectiveness of the model, start-up simulation results are compared with experimental result obtained for a prototype refrigeration cycle. In these experiments, the refrigerant mass distribution in the refrigeration cycle is set and two start-up operations are performed. One operation is called "hot-start", which means starting-up from a high temperature in the compressor chamber. The other is called "cold-start", which means starting-up from a low temperature. The simulation results well support the experimental results for both operations and prove the effectiveness of the developed model.

  10. Satellite-Supported Modeling of the Relationships between Urban Heat Island and Land Use/Cover Changes

    Science.gov (United States)

    Vahmani, P.; Ban-Weiss, G. A.

    2015-12-01

    Reliable assessment of the primary causes of urban heat island (UHI) and the efficiency of various heat mitigation strategies requires accurate prediction of urban temperatures and realistic representation of land surface physical characteristics in models. In this study, we expand the capabilities of the Weather Research and Forecasting (WRF) model and the Urban Canopy Model (UCM) by implementing high-resolution real-time satellite observations of green vegetation fraction (GVF), leaf area index (LAI), and albedo. We use MODIS-based GVF, LAI, and albedo to replace constant values that are assumed for urban pixels and climatological values that are used for non-urban pixels in the default WRF-UCM. Utilizing the improved model, summertime climate of Los Angeles is simulated over the span of three years (2010-2012). Next, thermal sensitivity of urban climate to anthropogenic land use/cover is assessed via replacing current urban cover with pre-development vegetation cover, consisting of shrubland and grassland. Surrounding undeveloped areas and inverse distance weighting method are utilized to estimate GVF and LAI of pre-development vegetation cover. Our analysis of diurnal and nocturnal surface and air temperatures shows cooling effects of urbanization in neighborhoods with high fractions of irrigated vegetation. However, urban warming is consistently detected over industrial/commercial and high-intensity residential areas. In addition to well-known mechanisms such as a shift in surface energy partitioning, high heat storage in urban material, and inefficiency of urban surfaces in transferring convective heat from the surface to the boundary layer, our results show decreased wind speed and sea breeze also contribute to the UHI intensity. We further evaluate the interactions between UHI and replacing irrigated and imported vegetation with non-irrigated native vegetation as a water conservation strategy in water-stressed Los Angeles metropolitan area.

  11. Evaporation of refrigerant HFC 407C on plain tubes or at an improved surface; Evaporation du refrigerant HFC 407C sur des tubes lisses ou a surface amelioree

    Energy Technology Data Exchange (ETDEWEB)

    Zuercher, O.; Favrat, D.; Thome, J.R.; Kattan, N.; Nidegger, E. [Ecole polytechnique federale, Lab. d`energetique industrielle, Lausanne (Switzerland)

    1996-11-15

    The substitution of CFC refrigerants in refrigeration systems, heat pumps and organic Rankine cycles for heat recovery, requires good methods for predicting heat transfer of substitute fluids. The measurements in the LENI test facility (concentric tubes with water flowing in a counter-current flow) with HFC 407C, HFC 134a, HCFC 123, HFC 404a and HFC/HCFC 402A provide a new data bank for new refrigerants, and allow a coherent comparison with old refrigerants CFC 11, CFC 12, CFC/HCFC 502 and with existing correlations. The existing correlations were found to be inadequate. Because of this work, an improved flow pattern map and flow boiling model were developed, which resulted in a substantial progress in the accurate predict of heat transfer in plain, horizontal tubes for refrigerants without oil. The Kattan et al. correlation was programmed to calculate and compare predicted heat transfer coefficients to the new HFC 407C test data. The flow pattern map proposed by Kattan et al. was also programmed and compared to flow regimes observed for HFC 407C. It predicted the HFC 407C flow pattern data quite accurately. The original objective of the HFC 407C measurements was the validation of the Kattan et al. correlation applied to a zeotropic refrigerant blend. Local flow boiling heat transfer coefficients were measured for HFC 407C evaporating inside a microfin and a plain tube. In addition, microfin heat transfer augmentation relative to a plain tube was investigated. The presence of oil in the evaporator had a complex effect on heat transfer coefficients. Local flow boiling heat transfer coefficients were measured for refrigerant HFC 407C ester oil mixtures (Mobil EAL Arctic 68). A new thermodynamic approach for modeling mixtures of zeotropic refrigerant blends and lubricating oils was also developed. (author) figs., tabs., 14 refs.

  12. Performance of R-410A Alternative Refrigerants in a Reciprocating Compressor Designed for Air Conditioning Applications

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Som S [ORNL; Vineyard, Edward Allan [ORNL; Mumpower, Kevin [Bristol Compressors International, Inc.

    2016-01-01

    In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. After successfully completing the first phase of the program in December 2013, AHRI launched a second phase of the Low-GWP AREP in 2014 to continue research in areas that were not previously addressed, including refrigerants in high ambient conditions, refrigerants in applications not tested in the first phase, and new refrigerants identified since testing for the program began. Although the Ozone Depletion Potential of R-410A is zero, this refrigerant is under scrutiny due to its high GWP. Several candidate alternative refrigerants have already demonstrated low global warming potential. Performance of these low-GWP alternative refrigerants is being evaluated for Air conditioning and heat pump applications to ensure acceptable system capacity and efficiency. This paper reports the results of a series of compressor calorimeter tests conducted for the second phase of the AREP to evaluate the performance of R-410A alternative refrigerants in a reciprocating compressor designed for air conditioning systems. It compares performance of alternative refrigerants ARM-71A, L41-1, DR-5A, D2Y-60, and R-32 to that of R-410A over a wide range of operating conditions. The tests showed that, in general, cooling capacities were slightly lower (except for the R-32), but energy efficiency ratios (EER) of the alternative refrigerants were comparable to that of R-410A.

  13. Experimental And Numerical Investigations of Ejector Jet Refrigeration System With Primary Stream Swirl

    OpenAIRE

    Parveen Banu, Jiautheen; Mallikarjuna, Jawali Maharudrappa; Mani, Annamalai

    2016-01-01

    Among the various heat powered refrigerated systems, vapour jet refrigeration system (VJRS) is attractive because of its simple and rugged nature. Ejector is a key component in VJRS and the performance of the whole system depends on the effective performance of the ejector. Ejector can be operated with low grade energy by utilizing the heat from solar energy, waste heat from industrial exhaust, automobile exhaust, etc, at minimum temperature of about 60°C[1]. Besides that, this system requir...

  14. A model for exergy analysis and thermodynamic bounds of Stirling refrigerators

    Science.gov (United States)

    Razani, A.; Dodson, C.; Roberts, T.

    2010-04-01

    A thermodynamic model based on exergy flow through a Stirling Refrigerator is developed. Important irreversibilities of the refrigerator due to external heat transfer with the reservoirs, heat leak, flow and heat transfer in regenerator are included in the model. Expansion and compression efficiencies are introduced in the model to account for the losses in these processes. The effect of a control phase shift between the mass flow rate and pressure across regenerator on the performance of the refrigerator is presented. Analytical solutions representing important quantities in the design of Stirling refrigerators such as the load curve, cooling power and efficiency in terms of basic system input parameters are developed. Thermodynamic bounds for the performance of Stirling refrigerators are obtained. Results indicating a compromise between cooling power and efficiency that are dependent on the constraint of the system are presented and discussed.

  15. Condensation of refrigerants on vertical fluted tubes

    Energy Technology Data Exchange (ETDEWEB)

    Combs, S.K.; Mailen, G.S.; Murphy, R.W.

    1978-08-01

    Experiments were run to determine heat transfer performance of single vertical fluted tubes with selected fluids condensing on the outside. Working fluids included six fluorocarbons (Refrigerants 11, 21, 22, 113, 114, and 115) and a hydrocarbon (Refrigerant 600a or isobutane). The nine test tubes were of 2.54-cm (1-in.) nominal outside diameter and 1.2 m (4 ft) in length with from 0 (smooth) to 60 axial flutes. Condensing heat transfer coefficients ranged from 620 to 7900 W/m/sup 2/ . K (110 to 1400 Btu/hr . ft/sup 2/ . /sup 0/F) over the heat flux range of 2000 to 43,000 W/m/sup 2/ (920 to 13,600 Btu/hr . ft/sup 2/). All parameters are based on total condensing surface area. The data show that, for a given heat flux, a fluted tube can increase condensing coefficients up to 6.0 times smooth tube values. Further heat transfer enhancement was achieved by the use of drainage skirts on fluted tubes; these skirts effectively divided the 1.2-m (4-ft) tubes into two, four, and eight equal condensing lengths.

  16. Satellite and Opacity Effects on Resonance Line Shapes Produced from Short-Pulse Laser Heated Foils

    Energy Technology Data Exchange (ETDEWEB)

    Shepherd, R; Audebert, P; Chen, H-K; Fournier, K B; Peyreusse, O; Moon, S; Lee, R W; Price, D; Klein, L; Gauthier, J C; Springer, P

    2002-12-03

    We measure the He-like, time-resolved emission from thin foils consisting of 250 {angstrom} of carbon-250 {angstrom} of aluminum and 500 {angstrom} aluminum illuminated with a 150 fs laser pulse at an intensity of 1 x 10{sup 19} W/cm{sup 2}. Dielectronic satellite contributions to the 1s{sup 2}-1s2p({sup 1}P), 1s{sup 2}-1s3p({sup 1}P), and 1s{sup 2}1s4p({sup 1}P) line intensities are modeled using the configuration averaged code AVERROES and is found to be significant for all three resonance lines. The contribution of opacity broadening is inferred from the data and found to be significant only in the 1s{sup 2}-1s2p({sup 1}P).

  17. Investigation of the "Elevated Heat Pump" hypothesis of the Asian monsoon using satellite observations

    OpenAIRE

    M. M. Wonsick; Pinker, R.T.; Ma, Y.

    2013-01-01

    In recent years, the "Elevated Heat Pump" (EHP) hypothesis has been a topic of intensive research and controversy. It postulates that aerosol-induced anomalous mid- and upper-tropospheric warming above the Tibetan Plateau leads to an early onset and intensification of Asian monsoon rainfall. The finding is primarily based on results from a NASA Finite-Volume General Circulation Model run with and without radiative forcing from different types of aerosols. In particular, black carbon emissions...

  18. Investigation of the "elevated heat pump" hypothesis of the Asian monsoon using satellite observations

    OpenAIRE

    M. M. Wonsick; Pinker, R.T.; Ma, Y.

    2014-01-01

    The "elevated heat pump" (EHP) hypothesis has been a topic of intensive research and controversy. It postulates that aerosol-induced anomalous mid- and upper-tropospheric warming in the Himalayan foothills and above the Tibetan Plateau leads to an early onset and intensification of Asian monsoon rainfall. This finding is primarily based on results from a NASA finite-volume general circulation model run with and without radiative forcing from different types of aerosols. In p...

  19. Estimation of surface latent heat fluxes from IRS-P4/MSMR satellite data

    Indian Academy of Sciences (India)

    Randhir Singh; B Simon; P C Joshi

    2001-09-01

    The brightness temperatures of the Microwave sensor MSMR (Multichannel Scanning Microwave Radiometer) launched in May 1999 onboard Indian Oceansat-1 IRS-P4 are used to develop a direct retrieval method for latent heat ux by multivariate regression technique. The MSMR measures the microwave radiances at 8 channels at frequencies of 6.6, 10.7, 18 and 21 GHz at both vertical and horizontal polarizations. It is found that the surface LHF (Latent Heat Flux) is sensitive to all the channels. The coeficients were derived using the National Centre for Environmental Prediction (NCEP) reanalysis data of three months: July, September, November of 1999. The NCEP daily analyzed latent heat uxes and brightness temperatures observed by MSMR were used to derive the coeficients. Validity of the derived coeficients was checked with in situ observations over the Indian Ocean and with NCEP analyzed LHF for global points. The LHF derived directly from the MSMR brightness temperature (Tb) yielded an accuracy of 35 watt/m2. LHF was also computed by applying bulk formula using the geophysical parameters extracted from MSMR. In this case the errors were higher apparently due to the errors involved in derivation of the geophysical parameters.

  20. Investigation of the "Elevated Heat Pump" hypothesis of the Asian monsoon using satellite observations

    Directory of Open Access Journals (Sweden)

    M. M. Wonsick

    2013-04-01

    Full Text Available In recent years, the "Elevated Heat Pump" (EHP hypothesis has been a topic of intensive research and controversy. It postulates that aerosol-induced anomalous mid- and upper-tropospheric warming above the Tibetan Plateau leads to an early onset and intensification of Asian monsoon rainfall. The finding is primarily based on results from a NASA Finite-Volume General Circulation Model run with and without radiative forcing from different types of aerosols. In particular, black carbon emissions from sources in Northern India and dust from Western China, Afghanistan, Pakistan, and Southwest Asia affected the modeled anomalous heating. Since the initial discussion of the EHP hypothesis in 2006, the aerosol-monsoon relationship has been addressed using various modeling and observational techniques. The current study takes an observational approach to detect signatures of the "Elevated Heat Pump" effect in the cloud cover and cloud type distributions as derived from Meteosat-5 observations over the Asian Monsoon region, supplemented with temperature data from the NCEP/NCAR Reanalysis and precipitation data from the Global Precipitation Climatology Project (GPCP. Cloud, convection, precipitation, and temperature features for the highest-aerosol years are compared with lower-aerosol content years during the period 2000–2005. Predicted precipitation features in China and Korea are found to be consistent with the hypothesis, but the early onset and intensification of monsoon rainfall over India are not observed. It is proposed that model inaccuracies and/or indirect aerosol effects caused the disagreement between observed and hypothesized behavior.

  1. Magnetic refrigeration: an eco-friendly technology for the refrigeration at room temperature

    Science.gov (United States)

    Aprea, C.; Greco, A.; Maiorino, A.; Masselli, C.

    2015-11-01

    Magnetic refrigeration is an emerging, environment-friendly technology based on a magnetic solid that acts as a refrigerant by magneto-caloric effect (MCE). In the case of ferromagnetic materials MCE is a warming as the magnetic moments of the atom are aligned by the application of a magnetic field, and the corresponding cooling upon removal of the magnetic field. There are two types of magnetic phase changes that may occur at the Curie point: first order magnetic transition (FOMT) and second order magnetic transition (SOMT). The reference cycle for magnetic refrigeration is AMR (Active Magnetic Regenerative cycle) where the magnetic material matrix works both as a refrigerating medium and as a heat regenerating medium, while the fluid flowing in the porous matrix works as a heat transfer medium. Regeneration can be accomplished by blowing a heat transfer fluid in a reciprocating fashion through the regenerator made of magnetocaloric material that is alternately magnetized and demagnetized. In this paper, attention is directed towards the near room-temperature range. We compare the energetic performance of a commercial R134a refrigeration plant to that of a magnetic refrigerator working with an AMR cycle. Attention is devoted to the evaluation of the environmental impact in terms of a greenhouse effect. The comparison is performed in term of TEWI index (Total Equivalent Warming Impact) that takes into account both direct and indirect contributions to global warming. In this paper the AMR cycle works with different magnetic refrigerants: pure gadolinium, second order phase magnetic transition (Pr0.45Sr0.35MnO3) and first order phase magnetic transition alloys (Gd5Si2Ge2, LaFe11.384Mn0.356Si1.26H1.52, LaFe1105Co0.94Si110 and MnFeP0.45As0.55). The comparison, carried out by means of a mathematical model, clearly shows that GdSi2Ge2 and LaFe11.384Mn0.356Si1.26H1.52 has a TEWI index always lower than that of a vapor compression plant. Furthermore, the TEWI of the AMR

  2. Analysis of room temperature magnetic regenerative refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Shir, F.; Mavriplis, C.; Bennett, L.H.; Torre, E.D. [George Washington University, Washington, DC (United States). Institute for Magnetics Research

    2005-06-01

    Results of a room temperature magnetic refrigeration test bed and an analysis using a computational model are presented. A detailed demonstration of the four sequential processes in the transient magnetocaloric regeneration process of a magnetic material is presented. The temperature profile during the transient approach to steady state operation was measured in detail. A 5 {sup o}C evolution of the difference of temperature between the hot end and the cold end of the magnetocaloric bed due to regeneration is reported. A model is developed for the heat transfer and fluid mechanics of the four sequential processes in each cycle of thermal wave propagation in the regenerative bed combined with the magnetocaloric effect. The basic equations that can be used in simulation of magnetic refrigeration systems are derived and the design parameters are discussed. (author)

  3. Transport Refrigeration Technician: Apprenticeship Course Outline. Apprenticeship and Industry Training. 4112

    Science.gov (United States)

    Alberta Advanced Education and Technology, 2012

    2012-01-01

    The graduate of the Transport Refrigeration Technician apprenticeship program is a certified journeyperson who will be able: (1) to diagnose repair, maintain and operate transport refrigeration equipment used to heat or cool the load as well as of diesel engines, APUs and other prime movers; (2) to use tools and equipment in order to carry out…

  4. Optimization of Multi-layer Active Magnetic Regenerator towards Compact and Efficient Refrigeration

    DEFF Research Database (Denmark)

    Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein

    2016-01-01

    Magnetic refrigerators can theoretically be more efficient than current vapor compression systems and use no vapor refrigerants with global warming potential. The core component, the active magnetic regenerator (AMR) operates based on the magnetocaloric effect of magnetic materials and the heat...

  5. CONCEPT OF AUTOMATIC CONTROL SYSTEM FOR IMPROVING THE EFFICIENCY OF THE ABSORPTION REFRIGERATING UNITS

    Directory of Open Access Journals (Sweden)

    O. Titlova

    2016-12-01

    Full Text Available The general concept of the automatic control systems constructing for increasing the efficiency of the artificial cold production process in the absorption refrigerating units is substantiated. The described automatic control systems provides necessary degree of the ammonia vapor purification from the water in all absorption refrigerating units modes and minimizes heat loss from the dephlegmator surface.

  6. Multilayer Thermionic Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Mahan, G.D.

    1999-08-30

    A review is presented of our program to construct an efficient solid state refrigerator based on thermionic emission of electrons over periodic barriers in the solid. The experimental program is to construct a simple device with one barrier layer using a three layers: metal-semiconductor-metal. The theoretical program is doing calculations to determine: (i) the optimal layer thickness, and (ii) the thermal conductivity.

  7. Autonomous solar refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Bougard, J.; Vokaert, D. (Faculte Polytechnique de Mons, Universite Libre de Bruxelles (Belgium))

    1982-11-01

    A compression refrigerator, fed by a flat solar pannel and composed of two thermal machines, working on a Rankine-Hirn cycle, is described. Mechanical energy is transferred by a double effect free-piston which is at the same time engine, pump, compressor and electric generator for auxiliaries. Freon R12 or R114 is used as the working fluid. Performances of a prototype are given. Investment for a classical unit, fed by a photovoltaic pannel would be more than twice.

  8. Continuous Magnetic Refrigerators for Cooling in the 0.05 to 10 K Range

    Science.gov (United States)

    Shirron, Peter; DiPirro, Michael; Canavan, Edgar; Tuttle, James; Panek, John; Jackson, Michael; King, Todd; Numazawa, Takenori; Krebs, Carolyn (Technical Monitor)

    2001-01-01

    Low temperature refrigeration is an increasingly vital technology for NASA's Space Science program since most detectors being developed for x-ray, IR and sub-millimeter missions must be cooled to below 100 mK in order to meet the requirements for energy and spatial resolution. For space applications, magnetic refrigeration has an inherent advantage over alternative techniques because it does not depend on gravity. Adiabatic demagnetization refrigerators, or ADRs, are relatively simple, solid state devices. The basic elements are a magnetocaloric refrigerant (usually an encapsulated paramagnetic salt) located in the bore of a superconducting magnet, and a heat switch linking the salt to a heat sink. The alignment of magnetic spins with the magnetic field causes the refrigerant to warm as the magnetic field increases and cool as the field decreases. Thus the simple process of magnetizing the refrigerant to high field with the heat switch closed, then demagnetizing it with the heat switch open allows one to obtain temperatures well below 100 mK using a heat sink as warm as 4.2 K. The refrigerant can maintain a low temperature for a length of time depending on the applied and parasitic heat loads, its mass, and the initial magnetic field strength. Typically ADRs are designed for 12-24 hours of hold time, after which they must be warmed up and recycled.

  9. Ecological balance for supermarket refrigeration in Switzerland; Oekobilanz fuer Supermarkt-Kaelteanlagen in der Schweiz

    Energy Technology Data Exchange (ETDEWEB)

    Frischknecht, R. [ESU-services, Uster (Switzerland)

    2000-04-01

    In the context of an ecological balance of heat pumps and refrigeration plants for the area supermarket cooling was stated that in respect of the environmental the greenhouse effect and ozone depletion give first priority to the selection of the refrigerant and the consistent minimization of the losses of refrigerant. The monitoring of the losses of refrigerant can be strongly improved. (orig.) [German] Im Rahmen einer Oekobilanz von Waermepumpen und Kaelteanlagen wurde fuer den Bereich Supermarktkaelte festgestellt, dass bei den Umweltwirkungen Treibhauseffekt und Ozonschichtabbau der Wahl des Kaeltemittels und der konsequenten Minimierung der Kaeltemittelverluste erste Prioritaet zukommt. Das Monitoring der Kaeltemittelverluste ist stark verbesserungsfaehig. (orig.)

  10. Development of a thermodynamic model for a cold cycle 3He-4He dilution refrigerator

    Science.gov (United States)

    Mueller, B. W.; Miller, F. K.

    2016-10-01

    A thermodynamic model of a 3He-4He cold cycle dilution refrigerator with no actively-driven mechanical components is developed and investigated. The refrigerator employs a reversible superfluid magnetic pump, passive check valves, a phase separation chamber, and a series of recuperative heat exchangers to continuously circulate 3He-4He and maintain a 3He concentration gradient across the mixing chamber. The model predicts cooling power and mixing chamber temperature for a range of design and operating parameters, allowing an evaluation of feasibility for potential 3He-4He cold cycle dilution refrigerator prototype designs. Model simulations for a prototype refrigerator design are presented.

  11. Research and Development Roadmap For Next-Generation Low-Global Warming Potential Refrigerants

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-07-01

    The Department of Energy commissioned this roadmap to establish a set of high-priority research and development (R&D) activities that will accelerate the transition to low-GWP refrigerants across the entire heating, ventilation, air-conditioning and refrigeration (HVAC&R) industry. The schedule of R&D activities occurs within an accelerated five-year timeframe, and covers several prominent equipment types. The roadmap is organized around four primary objectives to: assess and mitigate safety risks, characterize refrigerant properties, understand efficiency and environmental tradeoffs, and support new refrigerant and equipment development.

  12. Dilution Refrigeration of Multi-Ton Cold Masses

    CERN Document Server

    Wikus, P; CERN. Geneva

    2007-01-01

    Dilution refrigeration is the only means to provide continuous cooling at temperatures below 250 mK. Future experiments featuring multi-ton cold masses require a new generation of dilution refrigeration systems, capable of providing a heat sink below 10 mK at cooling powers which exceed the performance of present systems considerably. This thesis presents some advances towards dilution refrigeration of multi-ton masses in this temperature range. A new method using numerical simulation to predict the cooling power of a dilution refrigerator of a given design has been developed in the framework of this thesis project. This method does not only allow to take into account the differences between an actual and an ideal continuous heat exchanger, but also to quantify the impact of an additional heat load on an intermediate section of the dilute stream. In addition, transient behavior can be simulated. The numerical model has been experimentally verified with a dilution refrigeration system which has been designed, ...

  13. Investigation of the "elevated heat pump" hypothesis of the Asian monsoon using satellite observations

    Science.gov (United States)

    Wonsick, M. M.; Pinker, R. T.; Ma, Y.

    2014-08-01

    The "elevated heat pump" (EHP) hypothesis has been a topic of intensive research and controversy. It postulates that aerosol-induced anomalous mid- and upper-tropospheric warming in the Himalayan foothills and above the Tibetan Plateau leads to an early onset and intensification of Asian monsoon rainfall. This finding is primarily based on results from a NASA finite-volume general circulation model run with and without radiative forcing from different types of aerosols. In particular, black carbon emissions from sources in northern India and dust from Western China, Afghanistan, Pakistan, the Thar Desert, and the Arabian Peninsula drive the modeled anomalous heating. Since the initial discussion of the EHP hypothesis in 2006, the aerosol-monsoon relationship has been investigated using various modeling and observational techniques. The current study takes a novel observational approach to detect signatures of the "elevated heat pump" effect on convection, precipitation, and temperature for contrasting aerosol content years during the period of 2000-2012. The analysis benefits from unique high-resolution convection information inferred from Meteosat-5 observations as available through 2005. Additional data sources include temperature data from the NCEP/NCAR Reanalysis and the European Reanalysis (ERA-Interim) precipitation data from the Global Precipitation Climatology Project (GPCP), aerosol optical depth from the Multi-angle Imaging Spectroradiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS), and aerosol optical properties from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) aerosol reanalysis. Anomalous upper-tropospheric warming and the early onset and intensification of the Indian monsoon were not consistently observed during the years with high loads of absorbing aerosols. Possibly, model assumptions and/or unaccounted semi-direct aerosol effects caused the disagreement between observed and hypothesized

  14. 制冷系统不同表面能微通道的流动沸腾传热特性试验%Flowing boiling heat transfer characteristics test for microchannels with different surface energy in refrigeration system

    Institute of Scientific and Technical Information of China (English)

    罗小平; 邓聪; 冯振飞; 周建阳

    2016-01-01

    With the development of many applications in modern industrial system and equipment, the ability to dissipate a large amount of heat from small surface area has been becoming increasingly urgent. Flow boiling in microchannels provides unique advantages when applied in micro-module equipment. Therefore, the microchannel heat exchangers have a broad industrial and market prospects for their high heat transfer coefficients and appreciable reduction in weight and volume. Flow boiling heat transfer in microchannels becomes one of popular researching hot spots. But the researches about flow boiling in microchannels with different surface energy are still lacked and further researches are needed. In this study, the current experiments fabricated 3 different modules with the identical sizes of 240 mm × 400 mm × 7.5 mm and with the different surface energy. Flow boiling experiments were conducted with the refrigerant R141b in a test module containing 22 microchannels which were 2 mm wide and 1 mm deep. During the experiments, the heat flux imposed on the aluminum substrate varied from 9 to 26 kW/m2 and the mass flux flowing into the channel varied from 50 to 583 kg/(m2·s). The effects of the microchannels with different energy on boiling heat transfer under a certain pressure were experimentally investigated with different heat flux and mass flux. The results showed that the thermodynamic equilibrium quality increased fairly linearly with axial variation, with the slope inversely proportional to mass flow rate. The two-phase boiling heat transfer came earlier when mass flow rate was smaller and the increase of mass flow rate was beneficial to boiling heat transfer, but leading to the increasing of the length of the subcooled region. Heat transfer coefficient was relatively stable in the saturated boiling region of the microchannels and had a tendency to decrease along the flow direction due to the rise of gas phase proportion. Compared to the microchannels with the

  15. Pythagorean means and Carnot machines: When music meets heat

    CERN Document Server

    Johal, Ramandeep S

    2016-01-01

    Some interesting relations between Pythagorean means (arithmetic, geometric and harmonic means) and the coefficients of performance of reversible Carnot machines (heat engine, refrigerator and heat pump) are discussed.

  16. Coefficient of performance of Stirling refrigerators

    Science.gov (United States)

    E Mungan, Carl

    2017-09-01

    Stirling coolers transfer heat in or out of the working fluid during all four stages of their operation, and their coefficient of performance depends on whether the non-isothermal heat exchanges are performed reversibly or irreversibly. Both of these possibilities can in principle be arranged. Notably, if the working fluid is an ideal gas, the input of energy in the form of heat during one isochoric step is equal in magnitude to the output during the other isochoric step in the cycle. The theoretical performance of the fridge can then attain the reversible Carnot limit if a regenerator is used, which is a high heat capacity material through which the gas flows. Various Stirling refrigerator configurations are analysed in this article at a level of presentation suitable for an introductory undergraduate thermodynamics course.

  17. Japanese activities in refrigeration technology

    Science.gov (United States)

    Fujita, T.; Ohtsuka, T.; Ishizaki, Y.

    This paper reviews recent activities in refrigeration technology in Japan. The projects described are stimulated by growing industrial needs or form part of large national projects. The JNR project on the MAGLEV train is currently the most powerful activity and it demands knowledge in all the different disciplines of cryogenics in particular on various scales of refrigeration. Research activities are also directed towards the development of Stirling cycle and magnetic refrigerators for applications in a wider area.

  18. ALTERNATIVE REFRIGERANT R-134A

    Directory of Open Access Journals (Sweden)

    Rasim KARABACAK

    1997-03-01

    Full Text Available Because of the big damages on the ozone layer given by the refrigerants cloroflorocarbons that has been used up to now, new alternative gases should be developped and product at once. In this study, some informations about alternative to presently used CFCs, R-134A refrigerant's characteristics and its suitability to cooling systems is given. As it would be understood from these informations there is no objection on using alternative R-134A refrigerant

  19. The LSST Camera 500 watt -130 degC Mixed Refrigerant Cooling System

    Energy Technology Data Exchange (ETDEWEB)

    Bowden, Gordon B.; Langton, Brian J.; /SLAC; Little, William A.; /MMR-Technologies, Mountain View, CA; Powers, Jacob R; Schindler, Rafe H.; /SLAC; Spektor, Sam; /MMR-Technologies, Mountain View, CA

    2014-05-28

    The LSST Camera has a higher cryogenic heat load than previous CCD telescope cameras due to its large size (634 mm diameter focal plane, 3.2 Giga pixels) and its close coupled front-end electronics operating at low temperature inside the cryostat. Various refrigeration technologies are considered for this telescope/camera environment. MMR-Technology’s Mixed Refrigerant technology was chosen. A collaboration with that company was started in 2009. The system, based on a cluster of Joule-Thomson refrigerators running a special blend of mixed refrigerants is described. Both the advantages and problems of applying this technology to telescope camera refrigeration are discussed. Test results from a prototype refrigerator running in a realistic telescope configuration are reported. Current and future stages of the development program are described. (auth)

  20. The application of satellite data to study the effects of latent heat release on cyclones

    Science.gov (United States)

    Clark, J. H. E.

    1984-01-01

    Generalized energetics were studied for nonlinear inviscid symmetric instability (SI). It was found that the linear theory fails to predict the stability in certain cases where the basic state is transitional between stability and instability. The initial growth of the SI perturbations can be fairly well approximated by linear theory, but the long time nonlinear evaluations will be bonded energetically if the SI region is finite. However, a further extension of the energetics to conditional symmetric instability (CSI) shows that the nonlinear evolution of circulation will energetically depend much more on the precipitation in a complicated way. By treating the latent heat as a source which is implicitly related to the motion field, the existence, uniqueness and stability of steady viscous (CSI) circulations are studied. Viscous CSI circulations are proved to be unique and asymptotically stable when the heat sources are weak and less sensitive to the motion perturbations. By considering the fact that moist updrafts are narrow and using eddy viscosity of 0(1,000 m squared/s) the stability criterion suggests that some frontal rainbands were probably dominated by the CSI mechanism even in their mature quasi-steady stage.