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Sample records for absorption refrigeration cycle

  1. 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.

  2. Modeling of a Von Platen-Munters diffusion absorption refrigeration cycle

    Science.gov (United States)

    Agostini, Bruno; Agostini, Francesco; Habert, Mathieu

    2016-09-01

    This article presents a thermodynamical model of a Von-Platen diffusion absorption refrigeration cycle for power electronics applications. It is first validated by comparison with data available in the literature for the classical water-ammonia-helium cycle for commercial absorption fridges. Then new operating conditions corresponding to specific ABB applications, namely high ambient temperature and new organic fluids combinations compatible with aluminium are simulated and discussed. The target application is to cool power electronics converters in harsh environments with high ambient temperature by providing refrigeration without compressor, for passive components losses of about 500 W, with a compact and low cost solution.

  3. INJECTING ABSORPTION REFRIGERATION CYCLE%引射吸收式制冷循环

    Institute of Scientific and Technical Information of China (English)

    苏芬仙; 敖越; 等

    2001-01-01

    提出了引射吸收式制冷循环。它可以强化吸收,而且可以扩大吸收式制冷的应用领域。分析了引射吸收式制冷循环,提出了参数选择方法,分析了影响引射式吸收制冷循环中吸收过程的因素并与喷淋吸收过程进行了比较。%A new injecting absorption refrigeration cycle is put forward.The new refrigeration cycle can consolidate absorption of the absorption process and at the same time,the absorption refrigeration cycle can be used in more areas.The new refrigeration cycle is analyzed.A method of choosing the parameters is given.The factors are decribed which affect the absorption process.A comparison with the traditional absorption process is also made.

  4. 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.

  5. Comparison of the Performances of NH3-H20 and Libr-H2O Vapour Absorption Refrigeration Cycles

    Directory of Open Access Journals (Sweden)

    Prof. Nilesh B. Totla

    2016-04-01

    Full Text Available Developments in absorption cooling technology present an opportunity to achieve significant improvements on micro-scale to buildings, cooling, heating and power systems for residential and light commercial buildings. Their resultant effects are effective, energy efficient and economical. This study therefore contributes an important knowledge and method in the development, fabrication and application of an absorption refrigerator as a better alternative to the commonly used compressor refrigerators. Two fluid gas absorption refrigerators use electric based heater installed generator and no moving parts, such as pumps and compressors, and operate at a single system pressure. In this paper the performances analysis of the NH3-H2O and possible alternative cycles as lithium bromide-water are compared in respect of the (COP and different operating conditioning. The highest COP was found as a function of the absorber, generator, condenser, and evaporating temperature. This paper compares the performance of vapour absorption refrigeration cycles that are used for refrigeration temperatures below 0°C. Since the most common vapour absorption refrigeration systems use ammonia-water solution with ammonia as the refrigerant and water as the absorbent, research has been devoted to improvement of the performance of ammonia-water absorption refrigeration systems in recent years.

  6. Modelling the absorption refrigeration cycle using partially miscible working fluids by group contribution methods

    Science.gov (United States)

    Larkeche, O.; Meniai, A.-H.; Cachot, T.

    2012-06-01

    The present study concerns the cycle performance modelling of a particular configuration of an absorption refrigeration machine based on phase separation as well as development of a strategy for computer aided design of absorbents. The model uses predictive methods based on the group contribution concept for the computation of the thermodynamic phase equilibria involved such as liquid-liquid and vapour-liquid as well as enthalpy-concentration diagrams. The proposed absorbents computer-aided design strategy is based on the exploration of a number of structural group combinations obtained from a selected set of functional groups, according to the chemistry laws. The model was tested on four different absorbent-refrigerant pairs reported in the literature, namely (benzyl ethyl amine-glycerol), (water-hexanoic acid), (water-2-hexanone) and (water-ethyl propionate) as well as on pairs where the absorbent compound is generated by the proposed absorbent design strategy and the refrigerant is water. The results show that quite good values of the coefficient of performance (COP) can be obtained, indicating that this cycle configuration is promising and energetically efficient, mainly due to hardware savings, i.e. absence of condenser. However, other working fluid combinations have to be tested using the proposed model.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-03-01

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

  8. 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.

  9. Absorption cycle commercial refrigerator using wood burning cook stove; Geladeira de absorcao acionada por fogao a lenha

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Jose Tomaz Vieira; Martins, Gilberto [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia

    1990-12-31

    The current utilization of wood burning cook stoves in Brazil and the socio-economical profile of their users were surveyed. A traditional heavy-mass wood-burning cook stove was studied as a thermal equipment. Simple changes in the geometry of the combustion chamber were suggested to improve the cooking efficiency. A closed two-phase thermosyphon using water as working fluid was designed, built and connected between the combustion chamber of the cook stove and a depressurized absorption refrigeration system to determine the heat flux and the temperature level. A commercial refrigerator unit, using the absorption cycle, was coupled with the wood stove through the thermosyphon. The overall results of the coupling point to successful country-side applications. (author) 12 refs., 9 figs., 4 tabs.

  10. 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.

  11. Thermodynamic modelling of a double-effect LiBr-H2O absorption refrigeration cycle

    Science.gov (United States)

    Iranmanesh, A.; Mehrabian, M. A.

    2012-12-01

    The goal of this paper is to estimate the conductance of components required to achieve the approach temperatures, and gain insights into a double-effect absorption chiller using LiBr-H2O solution as the working fluid. An in-house computer program is developed to simulate the cycle. Conductance of all components is evaluated based on the approach temperatures assumed as input parameters. The effect of input data on the cycle performance and the exergetic efficiency are investigated.

  12. 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.

  13. Thermodynamical comparison and analysis of electric compression refrigeration cycle and absorption refrigeration cycle%电压缩式制冷循环与吸收式制冷循环的热力学比较分析

    Institute of Scientific and Technical Information of China (English)

    冯丽洁; 付林; 张世钢; 江亿

    2012-01-01

    Applying the exergy efficiency and exergy loss analysis method, calculates and compares the exergy efficiency between the electric compression refrigeration cycle and the single-effect absorption refrigeration cycle and the exergy losses of each part of the two cycles under the typical condition. The results show that the exergy efficiency of the two cycles is basically the same when the generator temperature and the heat source temperature are appropriately selected; most part of exercy losses of the electric compression refrigeration cycle occur in the compressor, and most part of exercy losses of the single-effect absorption refrigeration cycle occur in the absorber and generator. Discusses the improving methods for the two cycles.%采用(火用)效率与炯损失分析方法,计算比较了电压缩式制冷循环与单效吸收式制冷循环的(火用)效率及两种制冷循环在典型工况下各环节的(火用)损失.结果表明,当采用合适的发生器温度和热源温度时,两种制冷循环的(火用)效率基本相同;电压缩式制冷循环的主要(火用)损失发生在压缩机环节,吸收式制冷循环的主要(火用)损失发生在吸收器和发生器.讨论了两种制冷循环的改进途径.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  15. Development and proof-testing of advanced absorption refrigeration cycle concepts. Report on Phases 1 and 1A

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-03-01

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

  16. 一个新的吸收-喷射复合制冷循环%A NOVEL COMBINED EJECTOR-ABSORPTION REFRIGERATION CYCLE

    Institute of Scientific and Technical Information of China (English)

    洪大良; 唐黎明; 邹云霞; 何一坚; 陈光明

    2011-01-01

    提出了一个新的吸收-喷射复合制冷循环.在新循环中,部分冷凝器出口的饱和液态制冷剂被冷剂泵加压到制冷剂在发生温度下对应的饱和压力,这股高压制冷剂液体在一个沸腾器里被加热成饱和高压蒸气后将预热器出口的过热制冷剂蒸气引射到冷凝压力.由于在新循环中发生压力可以比冷凝压力低,因此该系统可以利用较低品位的热量制取低温下的冷量.研究结果表明:新循环可以利用比传统两级吸收式制冷循环温度更低的热源,制取同一温度下的冷量.此外,在蒸发温度或发生温度较低时,新循环的COP比单效循环高得多;当发生温度或蒸发温度较高时,新循环和传统单效循环的COP相同.%To make refrigeration at low temperature with low-grade heat source, a novel combined ejector-absorption refrigeration cycle was proposed in this paper. In the new cycle, part of saturated liquid refrigerant from the condenser was pumped to saturated pressure of the refrigerant at generation temperature. This stream was heated into saturated vapor in a boiler and injected the superheating refrigerant vapor from a preheater to condenser pressure. Since the generation pressure is lower than condenser pressure in the new cycle, the system can make refrigeration at low temperature with low-grade heat source. The research results show that the generation temperature of the new cycle is even lower than that of the conventional two-stage absorption refrigeration cycle to make refrigeration at the same low temperature. In addition, the COP of the new cycle is much higher than that of single-effect cycle at the low refrigeration temperature and generation temperature. If the refrigeration temperature or the temperature of heat source is high enough, the COP of the new cycle is the same as that of the conventional single-effect cycle.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Study on High Efficient Absorption Refrigerator Using Multi-effect Cycle

    Science.gov (United States)

    Inoue, Naoyuki; Irie, Tomoyoshi; Saito, Kiyoshi; Kawai, Sunao

    Double effect chillers are commonly used as cooling machines for air condition. Great efforts have been making to improve the efficiency for a long time, and now the COP is very near to the limitation of double effect cycles. Triple effect cycles are expected for the next step beyond double effect cycles, but have some problems of high temperature and high pressure in the high stage generator. High temperature of absorbent causes corrosion problem and high vapor pressure over atmospheric pressure causes the restriction of legal regulation. This paper deals with many types of triple effect cycles. The temperature and dew point of the high stage generator are analyzed, several types are selected for low dew point, and one of them is more analyzed in detail.

  2. 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.

  3. Simulation of a new combined absorption-compression refrigeration cycle%一种新型吸收-压缩复合制冷循环模拟

    Institute of Scientific and Technical Information of China (English)

    唐鹏武; 陈光明; 唐黎明; 刘利华

    2011-01-01

    A program compiled by Visual Basic language was used to simulate a new combined absorption-compression refrigeration cycle for performance research, including the effect of generation temperature , evaporation temperature, condensation temperature, heat flux and refrigeration capacity on system performance which was compared with a conventional vapour compression refrigeration cycle. Simulation results show that when generation temperature increases, the coefficient of performance ( COP) of new cycle increases first and then decreases. When evaporation temperature or heat flux increases, the COP of new cycle increases. When condensation temperature or refrigeration capacity increases, the COP of new cycle decreases. Under most simulation conditions, the COP of new cycle can be 10% higher than that of conventional vapour compression refrigeration cycle. The new cycle can not only reduce air conditioning load greatly, but also provide the possibility of efficient utilization of low grade energy such as solar energy.%为了对一种新型吸收-压缩复合制冷循环的性能进行模拟,使用Visual Basic语言自行编制了一个程序.该程序模拟了发生温度、蒸发温度、冷凝温度、加热量、制冷量对系统性能的影响,并将其性能与传统蒸气压缩式制冷循环作了对比.模拟结果表明:当发生温度升高时,新循环的制冷系数先增大后减小;当蒸发温度升高或加热量增大时,新循环的制冷系数增大;当冷凝温度升高或制冷量增大时,新循环的制冷系数减小.在大部分假定工况下,新循环的制冷系数比传统蒸气压缩式循环的高10%以上.新循环的提出不仅能够大幅度减少空调电力负荷,还为太阳能等低品位能源的高效利用提供了可能.

  4. 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...

  5. 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.

  6. Artificial neural network analysis of triple effect absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Hajizadeh Aghdam, A. [Department of Mechanical Engineering, Islamic Azad University (Iran, Islamic Republic of)], email: a.hajizadeh@iaukashan.ac.ir; Nazmara, H.; Farzaneh, B. [Department of Mechanical Engineering, University of Tabriz (Iran, Islamic Republic of)], email: h.nazmara@nioec.org, email: b_farzaneh_ms@yahoo.com

    2011-07-01

    In this study, artificial neural networks are utilized to predict the performance of triple effect series and parallel flow absorption refrigeration systems, with lithium bromide/water as the working fluid. Important parameters such as high generator and evaporator temperatures were varied and their effects on the performance characteristics of the refrigeration unit were observed. Absorption refrigeration systems make energy savings possible because they can use heat energy to produce cooling, in place of the electricity used for conventional vapour compression chillers. In addition, non-conventional sources of energy (such as solar, waste heat, and geothermal) can be utilized as their primary energy input. Moreover, absorption units use environmentally friendly working fluid pairs instead of CFCs and HCFCs, which affect the ozone layer. Triple effect absorption cycles were analysed. Results apply for both series and parallel flow systems. A relative preference for parallel-flow over series-flow is also shown.

  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. The use of absorption refrigeration systems in combined cycle power plants; Empleo de sistemas de refrigeracion por absorcion en plantas de ciclo combinado

    Energy Technology Data Exchange (ETDEWEB)

    Romero Paredes, H.; Ambriz, J.J.; Vargas, M.; Godinez, M.; Gomez, F.; Valdez, L.; Pantoja, G. [Universidad Autonoma Metropolitana, Unidad Iztapalapa, Departamento de Ingenieria de Procesos e Hidraulica, Mexico D. F. (Mexico)

    1995-12-31

    Day after day the electric power generation tends to be done in the most efficient way in order to diminish the generation costs and the rate of environmental pollution per KWh generated. This paper discusses the application of absorption refrigeration systems for the cooling of the air entering the compressor of a gas turbine in a combined cycle, in order to increase the mass air flow and with it the turbine output. The flows with remanent energy content that are not used in a combined cycle can be used for the operation of the absorption refrigeration system. This way, the required thermal energy for the cooling system is free. With this system it is possible to raise the gas turbine generation output from 5% to 25%. [Espanol] La generacion electrica dia con dia pretende realizarse de la manera mas eficiente posible con el objeto de disminuir los costos de generacion y la tasa de contaminacion ambiental por Kwh generado. En el presente trabajo se introduce la aplicacion de sistemas de refrigeracion por absorcion para el enfriamiento del aire de entrada al compresor de la turbina de gas de un ciclo combinado, con el objeto de aumentar el flujo masico del aire y con ello la potencia de salida de la turbina. Las corrientes con contenido remanente de energia termica que no se usan en una planta de ciclo combinado pueden servir para operar el sistema de refrigeracion por absorcion. De esta manera, la energia termica requerida para el sistema de enfriamiento es gratuita. Con este sistema es posible incrementar la potencia de generacion de la turbina de gas de 5 a 25%.

  9. 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).

  10. The Absorption Refrigerator as a Thermal Transformer

    Science.gov (United States)

    Herrmann, F.

    2009-01-01

    The absorption refrigerator can be considered a thermal transformer, that is, a device that is analogous to the electric transformer. The analogy is based on the correspondence between the extensive quantities, entropy and electric charge and the intensive variables, temperature and electric potential. (Contains 1 footnote and 6 figures.)

  11. The Absorption Refrigerator as a Thermal Transformer

    Science.gov (United States)

    Herrmann, F.

    2009-01-01

    The absorption refrigerator can be considered a thermal transformer, that is, a device that is analogous to the electric transformer. The analogy is based on the correspondence between the extensive quantities, entropy and electric charge and the intensive variables, temperature and electric potential. (Contains 1 footnote and 6 figures.)

  12. Compression-absorption cascade refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-04-01

    This paper describes the study carried out to analyse a refrigeration system in cascade with a compression system at the low temperature stage and an absorption system at the high temperature stage to generate cooling at low temperatures, as well as the possibility of powering it by means of a cogeneration system. CO{sub 2} and NH{sub 3} have been considered as refrigerants in the compression stage and the pair NH{sub 3}-H{sub 2}O in the absorption stage. The analysis has been realized by means of a mathematical model of the refrigeration system implemented in a computer program and taking into account the characteristic operating conditions of a cogeneration system with gas engines. The paper presents the results obtained regarding the performance of the refrigeration system and the adaptability between the power requirements of the refrigeration system and the power supplied by the cogeneration system taking into account the present Spanish Regulations about the use of cogeneration systems. [Author].

  13. An Exergy Analysis of LiBr-Water Absorption Refrigerators

    Science.gov (United States)

    Asano, Hitoshi; Fujii, Terushige; Wang, Xiao; Origane, Takafumi; Katayama, Masatoshi; Inoue, Umeo

    Absorption refrigerators are very efficient as a heat recovery unit in a co-generation system.In order to design an absorption refrigerator for an arbitrary heat source properly, it is important to consider not only quantity but also quality of heat flow. The evaluation of exergy loss in each component is also effective for the improvement of system. This paper deals with the exergy analysis on a LiBr-water absorption refrigerator consisted of a single-and a double-effect cycle driven by the exhaust gas of the micro gas turbine with the output power of about 30 kW. Moreover, exergy loss in absorption process was eva1uated. As a result, it was shown that 80% of the exergy loss in an absorber was caused in absorption process, and the exergy loss decreased with decreasing the change in solution concentration in absorber. In these calculated results,the maximum cooling load of 77.8 kW was obtained from the exhaust gas with the temperature of 2900°C by utilizing both a single-and a double-effect cycles in combination. The energy and exergy efficiency of the system was 88.0% and 25.6%, respectively.

  14. COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM

    OpenAIRE

    2005-01-01

    In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures.

  15. Short Time Cycles of Purely Quantum Refrigerators

    CERN Document Server

    Feldmann, Tova

    2012-01-01

    Four stroke Otto refrigerator cycles with no classical analogue are studied. Extremely short cycle times with respect to the internal time scale of the working medium characterize these refrigerators. Therefore these cycles are termed sudden. The sudden cycles are characterized by the stable limit cycle which is the invariant of the global cycle propagator. During their operation the state of the working medium possesses significant coherence which is not erased in the equilibration segments due to the very short time allocated. This characteristic is reflected in a difference between the energy entropy and the Von Neumann entropy of the working medium. A classification scheme for sudden refrigerators is developed allowing simple approximations for the cooling power and coefficient of performance.

  16. Thermodynamic evaluation of new absorbent mixtures of lithium bromide and organic salts for absorption refrigeration machines

    Energy Technology Data Exchange (ETDEWEB)

    Donate, Marina; Rodriguez, Luis; Lucas, Antonio De; Rodriguez, Juan F. [Department of Chemical Engineering, University of Castilla-La Mancha, Avda. de Camilo Jose Cela s/n, 13004 Ciudad Real (Spain)

    2006-01-01

    Mixtures of lithium bromide and organic salts of sodium and potassium (formate, acetate and lactate) have been evaluated as alternative absorbents for absorption refrigeration machines. The main objective is to overpass the limitations of lithium bromide and improve the characteristics and the efficiency of the refrigeration cycle. In order to select the mixture that presents better properties for its employment in absorption refrigeration cycles, a thermodynamic analysis have been done. Density, viscosity, enthalpies of dilution, solubility and vapour pressure data of the proposed mixtures have been measured. A simulation program has been developed to evaluate temperatures, heats exchanged in the different sections and the efficiency of the cycle. (author)

  17. Performance bound for quantum absorption refrigerators

    Science.gov (United States)

    Correa, Luis A.; Palao, José P.; Adesso, Gerardo; Alonso, Daniel

    2013-04-01

    An implementation of quantum absorption chillers with three qubits has been recently proposed that is ideally able to reach the Carnot performance regime. Here we study the working efficiency of such self-contained refrigerators, adopting a consistent treatment of dissipation effects. We demonstrate that the coefficient of performance at maximum cooling power is upper bounded by 3/4 of the Carnot performance. The result is independent of the details of the system and the equilibrium temperatures of the external baths. We provide design prescriptions that saturate the bound in the limit of a large difference between the operating temperatures. Our study suggests that delocalized dissipation, which must be taken into account for a proper modeling of the machine-baths interaction, is a fundamental source of irreversibility which prevents the refrigerator from approaching the Carnot performance arbitrarily closely in practice. The potential role of quantum correlations in the operation of these machines is also investigated.

  18. Computational Model of a Biomass Driven Absorption Refrigeration System

    Directory of Open Access Journals (Sweden)

    Munyeowaji Mbikan

    2017-02-01

    Full Text Available The impact of vapour compression refrigeration is the main push for scientists to find an alternative sustainable technology. Vapour absorption is an ideal technology which makes use of waste heat or renewable heat, such as biomass, to drive absorption chillers from medium to large applications. In this paper, the aim was to investigate the feasibility of a biomass driven aqua-ammonia absorption system. An estimation of the solid biomass fuel quantity required to provide heat for the operation of a vapour absorption refrigeration cycle (VARC is presented; the quantity of biomass required depends on the fuel density and the efficiency of the combustion and heat transfer systems. A single-stage aqua-ammonia refrigeration system analysis routine was developed to evaluate the system performance and ascertain the rate of energy transfer required to operate the system, and hence, the biomass quantity needed. In conclusion, this study demonstrated the results of the performance of a computational model of an aqua-ammonia system under a range of parameters. The model showed good agreement with published experimental data.

  19. Thermodynamic Analysis of Combined Vapor Compression and Vapor Absorption Refrigeration System

    Directory of Open Access Journals (Sweden)

    AAMIR SHAIKH

    2017-07-01

    Full Text Available Two of the popular refrigeration cycles, VC (Vapor Compression, and VA (Vapor Absorption are used extensively for refrigeration purposes. In this paper, a system is proposed that works using both cycles powered by an IC (Internal Combustion engine, where mechanical energy is used to run the VC cycle while exhaust gasses are used to operate the VA cycle. The VC cycle works on R12 refrigerant while LiBr-H2O combination is selected for operation of VA cycle. Firstly, the refrigeration system is modeled, followed by a parametric study to investigate the impacts of various operating parameters on the system performance. The results exhibit that for maximum chilling and overall performance, the condenser and evaporator pressures in the VC cycle are obtained as 710 and 340 kPa, respectively, whereas generator and absorber temperatures in VA cycle are 85 and 20oC, respectively

  20. Performance comparison of magnetic refrigeration cycles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, F.C.; Chen, G.L.; Murphy, R.W.; Mei, V.C.

    1990-01-01

    Magnetic refrigeration has been used for cryogenic cooling at temperatures near absolute zero for many years. In these cases, a single-step adiabatic demagnetization method that does not provide continuous refrigeration is commonly used. The possibilities of providing continuous cooling through magnetic refrigeration cycles and of extending the range of applications above near-absolute-zero temperatures have been investigated only in recent years. This paper reports the results of a parametric performance study of three magnetic refrigeration cycles using four rare-earth magnetic materials operating near their respective Curie temperatures. The thermodynamic cycles employed are the magnetic-equivalent Carnot, Ericsson, and ideal regenerative cycles, and the four magnetic materials are terbium, holmium, erbium, and thulium. Our findings show that the Carnot cycle is not possible for cases of temperature lift beyond 10 K for a magnetic field variation of Tesla, that the performance and capacity of an ideal regenerative cycle are higher than that of the corresponding Ericsson cycle, and that the magnetocaloric effects of erbium and thulium seem to be too weak for practical applications. 14 refs., 14 figs.

  1. 两种新型太阳能吸收式制冷循环系统%Two Types of New Solar-Absorption Refrigeration Cycle System

    Institute of Scientific and Technical Information of China (English)

    李志生; 曾涛; 郭初

    2014-01-01

    介绍了太阳能制冷的实现途径和太阳能吸收式制冷系统的研究现状,分析了传统型太阳能吸收式制冷系统的缺点与存在的问题,提出了两种新型太阳能吸收式制冷系统:即在传统的系统基础上增加了压缩式热泵系统(新型A);在太阳能集热器中加入相变蓄能材料,且将热泵系统的蒸发器与太阳能集热器合为一体(新型B)。详细介绍了两种新型系统的工作原理,分析了的系统优缺点。新型系统可以较好利用太阳能实现制冷,能解决传统型系统存在的弊端,为太阳能空调系统的优化提供了新的研究方向。%The realization ways of the solar cooling is introduced, as well as the current research status of solar-absorption refrigeration system. The shortcomings and problems in the traditional solar-absorption refrigeration system are analyzed, proposing two types of new solar-absorption refrigeration system, including model A - system adding a compression heat pump system based on the traditional system; model B - system adding the phase-change energy storage material in solar collector, and com-bining the heat pump system’s evaporator and solar collector together. The working principles of new sys-tems are expounded in details, with analysis on strengths and weaknesses of systems. The new systems can better use solar energy to realize refrigeration, and can solve the drawbacks of the traditional system, pro-vides a new research direction for the optimization of solar air conditioning system.

  2. Coefficient of Performance Enhancement of Refrigeration Cycles

    Directory of Open Access Journals (Sweden)

    Eng. Naser R. M. AL-Ajmi

    2015-03-01

    Full Text Available Refrigerator is one of the home appliance utilizing mechanical vapor compression cycle in its process. Performance of the systems become the main issue and many researches are still ongoing to evaluate and improve the efficiency of any used system. Therefore, this paper presents an experimental investigation of the performance of the refrigeration cycles. A small rrefrigerator is used as the test rig. The Coefficient of Performance (COP is studied by using different condenser designs and under varying evaporator loads. Three condenser designs are used in present work. These condensers are regular condenser of domestic refrigerator, condenser with copper plain tubes (Cond.1 and condenser with copper tubes welded with stainless steel flat plate (Cond.2. pressures and temperatures measurements of each point in the refrigeration cycle are collected in order to evaluate the refrigerator performance. The results showed that the average COP of Cond.1 and Cond.2 are increased up to 20 % and 14% respectively more than regular condenser design under no load. The evaporator load effects on the machine performance, where the COP of the machine increases with the increase of the evaporator load.

  3. Mapping of optimum operating condition for LiBr–water refrigeration cycles

    Indian Academy of Sciences (India)

    NILESH A MALI; SUNIL S BHAGWAT

    2017-02-01

    In this work, optimum operating condition maps are generated covering wide ranges of refrigeration and sink temperatures for single- and double-effect LiBr–water vapour absorption refrigeration cycle. These optimum condition maps will be useful to choose optimum operating conditions while designing LiBr–water cycle for desired applications. Methodology for generating such maps is discussed in detail, which can also beused for other absorption refrigeration cycles with various working fluids. Three configurations of LiBr–water absorption refrigeration cycles, single effect, double-effect series flow and double-effect parallel flow, are analysed with the most accurate thermodynamic property correlation available in the literature. Sensitivity of cycle performance to various operating variables such as generator, absorber and condenser temperatures is determined. Second law analysis shows that when a higher temperature heat source is available, double-effect cycles are more effective over single effect as they have higher coefficient of performance.

  4. Design and Simulation of an Absorption Diffusion Solar Refrigeration Unit

    Directory of Open Access Journals (Sweden)

    B. Chaouachi

    2007-01-01

    Full Text Available The purpose of this study was the design and the simulation of an absorption diffusion refrigerator using solar as source of energy, for domestic use. The design holds account about the climatic conditions and the unit cost due to technical constraints imposed by the technology of the various components of the installation such as the solar generator, the condenser, the absorber and the evaporator. Mass and energy conservation equations were developed for each component of the cycle and solved numerically. The obtained results showed, that the new designed mono pressure absorption cycle of ammonia was suitable well for the cold production by means of the solar energy and that with a simple plate collector we can reach a power, of the order of 900 watts sufficient for domestic use.

  5. 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...

  6. Performance of an irreversible quantum refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    He Ji-Zhou; Ouyang Wei-Pin; Wu Xin

    2006-01-01

    A new model of a quantum refrigeration cycle composed of two adiabatic and two isomagnetic field processes is established. The working substance in the cycle consists of many non-interacting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semi-group approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate, and power input, are given. It is found that the coefficient of performance of this cycle is in the closest analogy to that of the classical Carnot cycle. Furthermore, at high temperatures the optimal relations of the cooling rate and the maximum cooling rate are analysed in detail. Some performance characteristic curves of the cycle are plotted, such as the cooling rate versus the maximum ratio between high and low "temperatures" of the working substances, the maximum cooling rate versus the ratio between high and low "magnetic fields" and the "temperature" ratio between high and low reservoirs. The obtained results are further generalized and discussed, so that they may be directly applied to describing the performance of the quantum refrigerator using spin-J systems as the working substance. Finally, the optimum characteristics of the quantum Carnot and Ericsson refrigeration cycles are derived by analogy.

  7. 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.

  8. THERMODYNAMIC ANALYSIS AND SIMULATION OF A NEW COMBINED POWER AND REFRIGERATION CYCLE USING ARTIFICIAL NEURAL NETWORK

    Directory of Open Access Journals (Sweden)

    Hossein Rezvantalab

    2011-01-01

    Full Text Available In this study, a new combined power and refrigeration cycle is proposed, which combines the Rankine and absorption refrigeration cycles. Using a binary ammonia-water mixture as the working fluid, this combined cycle produces both power and refrigeration output simultaneously by employing only one external heat source. In order to achieve the highest possible exergy efficiency, a secondary turbine is inserted to expand the hot weak solution leaving the boiler. Moreover, an artificial neural network (ANN is used to simulate the thermodynamic properties and the relationship between the input thermodynamic variables on the cycle performance. It is shown that turbine inlet pressure, as well as heat source and refrigeration temperatures have significant effects on the net power output, refrigeration output and exergy efficiency of the combined cycle. In addition, the results of ANN are in excellent agreement with the mathematical simulation and cover a wider range for evaluation of cycle performance.

  9. Energy and Exergy Analysis of Vapour Absorption Refrigeration Cycle—A Review

    Science.gov (United States)

    Kanabar, Bhaveshkumar Kantilal; Ramani, Bharatkumar Maganbhai

    2016-07-01

    In recent years, an energy crisis and the energy consumption have become global problems which restrict the sustainable growth. In these scenarios the scientific energy recovery and the utilization of various kinds of waste heat become very important. The waste heat can be utilized in many ways and one of the best practices is to use it for vapour absorption refrigeration system. To ensure efficient working of absorption cycle and utilization of optimum heat, exergy is the best tool for analysis. This paper provides the comprehensive picture of research and development of absorption refrigeration technology, practical and theoretical analysis with different arrangements of the cycle.

  10. Analysis of Refrigeration Cycle Performance with an Ejector

    OpenAIRE

    Wani J. R.; Baheta Aklilu T.; Woldeyohannes Abraham D.; Hassan Suhaimi

    2016-01-01

    A conventional refrigeration cycle uses expansion device between the condenser and the evaporator which has losses during the expansion process. A refrigeration cycle with ejector is a promising modification to improve the performance of conventional refrigeration cycle. The ejector is used to recover some of the available work so that the compressor suction pressure increases. To investigate the enhancement a model with R134a refrigerant was developed. To solve the set of equations and simul...

  11. Performance Characteristics of Absorption Hybrid Cycle Introduced Compressor

    Science.gov (United States)

    Iyoki, Shigeki; Kotani, Yuji; Uemura, Tadashi

    In this paper, four kinds of absorption hybrid cycle which introduced the compressor in the absorption cycle were proposed. As basic cycle of absorption refrigerating machine, the following were chosen: two kinds of single-stage absorption refrigerating machine and two kinds of double effect absorption refrigerating machine. As a working medium-absorbent system, NH3-H2O system, C2H5NH2-H2O system and C2H5NH2-H2O-LiBr system were adopted. Using these three kinds of working medium-absorbent system, the performance characteristics of four kinds of absorption hybrid cycle were simulated. And the performance characteristics of these cycles were compared.

  12. Compact Claude cycle refrigerator for laboratory use

    Science.gov (United States)

    Hiersaki, Y.; Kaneko, M.; Munekata, T.; Baba, Y.; Matsubara, Y.; Yasukochi, K.

    1983-12-01

    A Claude cycle refrigerator with a three stage reciprocating expansion engine is described. Instead of a cam mechanism, valves are driven directly by magnetic solenoids operated by means of a micro processor control system. A swash plate mechanism is used to convert reciprocating motion of the expander pistons to rotary motion. A refrigeration capacity of 8 watts was achieved at 4.5 K with the operating pressure of 1.1 MPa and flow rate of 2.4 g/sec.. An effect of overintake operation was studied. Experimental results show that the efficiency of the expander has a peak point in the region of overintake operation with constant cycle speed, which agrees with theoretical results. The electrically controlled valve system is useful to vary the valve timing to achieve an optimum condition of operation.

  13. Compact Claude cycle refrigerator for laboratory use

    Science.gov (United States)

    Hiersaki, Y.; Kaneko, M.; Munekata, T.; Baba, Y.; Matsubara, Y.; Yasukochi, K.

    1983-01-01

    A Claude cycle refrigerator with a three stage reciprocating expansion engine is described. Instead of a cam mechanism, valves are driven directly by magnetic solenoids operated by means of a micro processor control system. A swash plate mechanism is used to convert reciprocating motion of the expander pistons to rotary motion. A refrigeration capacity of 8 watts was achieved at 4.5 K with the operating pressure of 1.1 MPa and flow rate of 2.4 g/sec.. An effect of overintake operation was studied. Experimental results show that the efficiency of the expander has a peak point in the region of overintake operation with constant cycle speed, which agrees with theoretical results. The electrically controlled valve system is useful to vary the valve timing to achieve an optimum condition of operation.

  14. COMPARISON OF ENERGY AND EXERGY EFFICIENCIES OF ABSORPTION REFRIGERATION SYSTEM WITH MECHANICAL COMPRESSION REFRIGERATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Gülay YAKAR

    2005-02-01

    Full Text Available In this study, energy and exergy analysis of absorption refrigeration system using LiBr- water and mechanical compression refrigeration system using R134-a were performed at different evaporation temperatures. The results are presented in tables and figures.

  15. A Cold Cycle Dilution Refrigerator for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The cold cycle dilution refrigerator is a continuous refrigerator capable of cooling to temperatures below 100 mK that makes use of a novel thermal magnetic pump....

  16. 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.

  17. Regenerative characteristics of magnetic or gas Stirling refrigeration cycle

    Science.gov (United States)

    Chen, J.; Yan, Z.

    A general criterion to distinguish whether a Stirling refrigeration cycle possesses the condition of perfect regeneration is given. It is proven using the criterion that a Stirling refrigeration cycle using a simple paramagnetic or ferromagnetic material as the working substance possesses the condition of perfect regeneration, as does a Stirling refrigeration cycle using an ideal or van der Waals gas as the working substance. However, a Stirling refrigeration cycle using a gas which is described by the Redlich-Kwong, Beattie-Bridgeman, Benedict-Webb-Rubin, Dieterici, Berthelot, or Martin-Hou equation as the working substance does not possess the condition of perfect regeneration and its coefficient of performance is always smaller than that of the Carnot refrigeration cycle for the same temperature range. Moreover, the effect of non-perfect regeneration on the level of refrigeration and the coefficient of performance of a Stirling refrigeration cycle is expounded using a strict equation of state.

  18. Open cycle liquid desiccant dehumidifier and hybrid solar/electric absorption refrigeration system. Annual report, January 1993--December 1993. Calendar year 1993

    Energy Technology Data Exchange (ETDEWEB)

    Nimmo, B.G.; Thornbloom, M.D.

    1995-04-01

    This annual report presents work performed during calendar year 1993 by the Florida Solar Energy Center under contract to the US Department of Energy. Two distinctively different solar powered indoor climate control systems were analyzed: the open cycle liquid desiccant dehumidifier, and an improved efficiency absorption system which may be fired by flat plate solar collectors. Both tasks represent new directions relative to prior FSEC research in Solar Cooling and Dehumidification.

  19. Analysis of Refrigeration Cycle Performance with an Ejector

    Directory of Open Access Journals (Sweden)

    Wani J. R.

    2016-01-01

    Full Text Available A conventional refrigeration cycle uses expansion device between the condenser and the evaporator which has losses during the expansion process. A refrigeration cycle with ejector is a promising modification to improve the performance of conventional refrigeration cycle. The ejector is used to recover some of the available work so that the compressor suction pressure increases. To investigate the enhancement a model with R134a refrigerant was developed. To solve the set of equations and simulate the cycle performance a subroutine was written on engineering equation solver (EES environment. At specific conditions, the refrigerant properties are obtained from EES. At the design conditions the ejector refrigeration cycle achieved 5.141 COP compared to 4.609 COP of the conventional refrigeration cycle. This means that ejector refrigeration cycle offers better COP with 10.35% improvement compared to conventional refrigeration cycle. Parametric analysis of ejector refrigeration cycle indicated that COP was influenced significantly by evaporator and condenser temperatures, entrainment ratio and diffuser efficiency.

  20. 新型太阳能吸收式制冷循环系统性能分析%ON THE PERFORMANCE ANALYSIS OF A NEW ABSORPTION REFRIGERATION CYCLE SYSTEM FOR SOLAR ENERGY

    Institute of Scientific and Technical Information of China (English)

    刘丽; 孔兵; 张迪凡

    2015-01-01

    On the basis of the traditional two-level lithium bromide absorption refrigeration cycle, considering that the heat can be increased by the temperature difference, this paper proposes a new absorption refrigeration cycle driven by solar energy to an-alyze and calculate the influence of the system thermal coefficient COP as well as available temperature difference made by the heat source under the low-voltage generator pressure (intermediate pressure) and intermediate solution concentration change. The results show that, within the scope of the occurrence of the heat source temperature of 85℃-95℃, the intermediate pressure be-tween 1.6KPa (12mmHg) and 2.2KPa (16.5mmHg) can obtain the new value which has a higher thermodynamic cycle coeffi-cient and the temperature difference of a larger heat source.%在传统两级溴化锂吸收式制冷循环的基础上,从增大热源可利用温差考虑,提出了一种由太阳能驱动的新型吸收式制冷循环,分析计算了低压发生器压力(中间压力)和中间溶液浓度变化对系统热力系数COP和热源可利用温差的影响。结果表明,在发生热源温度85℃~95℃的范围内,中间压力在1.6KPa (12mmHg)和2.2KPa (16.5mmHg)之间取值新型循环有较高的热力系数和较大的热源可利用温差。

  1. 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.

  2. Fundamental Study of Absorption Cycle without Electric Solution Pump

    Science.gov (United States)

    Tsujimori, Atsushi; Sato, Kazuo; Nakao, Kazushige; Ohgushi, Tetsuro; Katsuta, Masafumi

    The absorption refrigerant cycle has been used in Japan, as energy shortage problem is more and more serious and environmental protection is of increasing importance. This type of air conditioner and chiller consume less electric power input than the electric one. However, the absorption refrigerator of large cooling capacity consumes some electric power with the required facility. Then in this research, the absorption cycle without the electric solution pump is proposed using a capillary pump and the possibility of making this cycle running using LiBr solution as a working fluid is investigated. As a result, it was found that the absorption cycle could be reached using a capillary wick in the generator to circulate the refrigerant and kept the strong and weak solution low pressure.

  3. Research on performance of mixed absorption refrigeration for solar air-conditioning

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel lithium bromide/water mixed absorption refrigeration cycle that is suitable for the utilization of solar air-conditioning and can overcome the drawbacks of low system overall efficiency of traditional solar absorption refrigeration air-condition systems is presented.The accessorial high pressure generator was added in the cycle.The lithium bromide solution flowing out from the high pressure generator was mixed with the solution from the low pressure absorber to increase lithium bromide solution concentration and decrease pressure in the high pressure absorber.The performance of a mixed absorption refrigeration cycle was analyzed.The theoretical analysis shows that the highest COP is 0.61,while the highest available temperature difference of heat resource is 33.2℃.The whole coefficient of performance of the solar air-conditioning using mixed absorption cycle is 94.5% higher than that of two-stage absorption.The advantages of solar air-conditioning can be markedly made use of by the cycle.

  4. 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.

  5. Research on a New Type of Solar-driven Air-cooled NH3H2O Absorption Refrigeration Cycle%新型太阳能风冷氨水吸收式制冷循环的研究

    Institute of Scientific and Technical Information of China (English)

    任秀宏; 王林

    2012-01-01

    A new type of solar-driven air-cooled NH3H2O absorption refrigeration cycle was proposed. It have rectification e-quipment for purifying ammonia steam and recovers heat from rectifier and absorber. By these realizing small size, air - cooled and the effective use of solar energy. So the coefficient of performance (COP) is increased compared with traditional models. Based on energy conservation, solution mass conservation and ammonia components mass conservation,the thermodynamic math-ematic model of each component is established. Then cycle performance is calculated by writing programs. The effect of main operation parameters(heat source temperature, evaporating temperature,condensing temperature)on the coefficient of performance ( COP) was studied, laying the foundation for optimization design and operation of refrigeration system.%提出一种新型太阳能风冷氨水吸收式制冷循环系统,该系统设置精馏器提纯氨蒸汽,并有效回收精馏器精馏热及中温吸收器吸收热,实现对太阳能的有效利用以及机组风冷化和小型化,与传统系统相比其系统性能系数(COP)显著提高.基于能量守恒、溶液质量守恒和氨组分质量守恒建立系统各部件热力学数学模型,在此基础上编写程序对系统循环特性进行理论计算,分析热源温度、蒸发温度、冷凝温度等参数对系统COP的影响,为系统优化设计及建立最优运行方案提供理论支持.

  6. Applying design of experiments to a compression refrigeration cycle

    Directory of Open Access Journals (Sweden)

    Nuno Ricardo Costa

    2015-12-01

    Full Text Available Refrigeration cycles are used in a large diversity of industrial and domestic (residential and non-residential equipment and their efficiency depend on several variables. To better understanding of how controllable variables impact on a compression refrigeration cycle efficiency, statistically designed experiments were conducted and data were analyzed. A quadratic polynomial model was fitted to Coefficient of Performance and variable settings to maximize cycle efficiency identified. Results give confidence to use the illustrated approach for refrigeration cycle design and operation improvement purposes.

  7. New Regenerative Cycle for Vapor Compression Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Mark J. Bergander

    2005-08-29

    second step of compression. In the proposed system, the compressor compresses the vapor only to 50-60% of the final pressure, while the additional compression is provided by a jet device using internal potential energy of the working fluid flow. Therefore, the amount of mechanical energy required by a compressor is significantly reduced, resulting in the increase of efficiency (either COP or EER). The novelty of the cycle is in the equipment and in the way the multi-staging is accomplished. The anticipated result will be a new refrigeration system that requires less energy to accomplish a cooling task. The application of this technology will be for more efficient designs of: (1) Industrial chillers, (2) Refrigeration plants, (3) Heat pumps, (4) Gas Liquefaction plants, (5) Cryogenic systems.

  8. A cold ejector for closed-cycle helium refrigerators

    Science.gov (United States)

    Johnson, D. L.; Daggett, D. L.

    1987-11-01

    The test results are presented of an initial cold helium ejector design that can be installed on a closed cycle refrigerator to provide refrigeration at temperatures below 4.2 K. The ejector, test apparatus, instrumentation, and test results are described. Tests were conducted both at room temperature and at cryogenic temperatures to provide operational experience with the ejector as well as for future use in the subsequent design of an ejector that will provide refrigeration at temperatures below 3 K.

  9. A cold ejector for closed-cycle helium refrigerators

    Science.gov (United States)

    Johnson, D. L.; Daggett, D. L.

    1987-01-01

    The test results are presented of an initial cold helium ejector design that can be installed on a closed cycle refrigerator to provide refrigeration at temperatures below 4.2 K. The ejector, test apparatus, instrumentation, and test results are described. Tests were conducted both at room temperature and at cryogenic temperatures to provide operational experience with the ejector as well as for future use in the subsequent design of an ejector that will provide refrigeration at temperatures below 3 K.

  10. Modeling And Experimental Analysis Of Generator In Vapour Absorption Refrigeration System

    Directory of Open Access Journals (Sweden)

    Christy V Vazhappilly

    2013-09-01

    Full Text Available A breadboard prototype of an absorption system for refrigeration using heat from the exhaust-gases is to be designed, built and tested. In the commercial vapour absorption refrigeration system a heating coil generator system has been employed to vaporize the ammonia efrigerant. In the present work, the heating coil generator system has been replaced by the frame plate type heat exchanger. The exhaust gases from the IC engine have been utilized to vaporize the ammonia refrigerant. The available heat in the exhaust gases has to be estimated based on actual I.C-Engine driving cycles. The frame plate type heat exchanger has to be modeled and flow analysis inside the heat exchanger has to be analyzed. In addition, the recoverable energy of the exhaust gases is to be analyzed for representative Internal Combustion Engine.

  11. 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.

  12. Experimental Investigation on an Absorption Refrigerator Driven by Solar Cells

    Directory of Open Access Journals (Sweden)

    Zi-Jie Chien

    2013-01-01

    Full Text Available This experiment is to study an absorption refrigerator driven by solar cells. Hand-held or carried in vehicle can be powered by solar energy in places without power. In the evenings or rainy days, it is powered by storage battery, and it can be directly powered by alternating current (AC power supply if available, and the storage battery can be charged full as a backup supply. The proposed system was tested by the alternation of solar irradiance 550 to 700 W/m2 as solar energy and 500ml ambient temperature water as cooling load. After 160 minutes, the proposal refrigerator can maintain the temperature at 5–8°C, and the coefficient of performance (COP of NH3-H2O absorption refrigeration system is about 0.25. Therefore, this system can be expected to be used in remote areas for refrigeration of food and beverages in outdoor activities in remote and desert areas or long-distance road transportation of food or low temperature refrigeration of vaccine to avoid the deterioration of the food or the vaccines.

  13. Cavity-enhanced absorption for optical refrigeration

    CERN Document Server

    Seletskiy, Denis V; Sheik-Bahae, Mansoor

    2009-01-01

    A 20-fold increase over the single path optical absorption is demonstrated with a low loss medium placed in a resonant cavity. This has been applied to laser cooling of Yb:ZBLAN glass resulting in 90% absorption of the incident pump light. A coupled-cavity scheme to achieve active optical impedance matching is analyzed.

  14. Applying design of experiments to a compression refrigeration cycle

    OpenAIRE

    Nuno Ricardo Costa; João Garcia

    2015-01-01

    Refrigeration cycles are used in a large diversity of industrial and domestic (residential and non-residential) equipment and their efficiency depend on several variables. To better understanding of how controllable variables impact on a compression refrigeration cycle efficiency, statistically designed experiments were conducted and data were analyzed. A quadratic polynomial model was fitted to Coefficient of Performance and variable settings to maximize cycle efficiency identified. Results ...

  15. Lanthanide Al-Ni base Ericsson cycle magnetic refrigerants

    Science.gov (United States)

    Gschneidner, Jr., Karl A.; Takeya, Hiroyuki

    1995-10-31

    A magnetic refrigerant for a magnetic refrigerator using the Ericsson thermodynamic cycle comprises DyAlNi and (Gd.sub.0.54 Er.sub.0.46)AlNi alloys having a relatively constant .DELTA.Tmc over a wide temperature range.

  16. 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.

  17. Absorber-evaporator unit for an absorption-refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Hallatt, R.J.; Rorschach, R.L.

    1965-01-26

    This low temperature absorption-refrigeration system uses an absorber-evaporator. A conduit is connected between the upper portion of the absorber and the lower portion of the evaporator to conduct inert gas from the absorber to the evaporator. A second conduit connects the upper portion of the evaporator to the lower portion of the absorber and a blower in this conduit circulates the inert gas through the closed system. By placing the blower between the evaporator ad the absorber, the pressure in the evaporator is maintained at a minimum so that the working temperature is as low as possible. The medium to be cooled by the refrigerant is circulated through a heat exchanger located within the evaporator, whereby the latent heat of vaporization of the liquid refrigerant is employed to cool the outside medium. (2 claims)

  18. 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.

  19. Nanofibrous membrane-based absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

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

  20. 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.

  1. Modelling of the generation phase of an absorption cooling cycle operating intermittently; Modelisation de la phase generation d'un cycle de refrigeration par absorption solaire a fonctionnement intermittent

    Energy Technology Data Exchange (ETDEWEB)

    Boukhchana, Yasmina; Fellah, Ali; Ben Brahim, Ammar [Unite de Recherche, Thermodynamique Appliquee (99/UR/11-21), Universite de Gabes, Ecole Nationale d' ingenieurs, 6072 Gabes (Tunisia)

    2011-01-15

    No abstract prepared. [French] La modelisation en regime dynamique de la phase generation d'une installation frigorifique a absorption solaire a fonctionnement intermittent utilisant le couple ammoniac/eau a ete elaboree. L'etude basee sur l'intermittence du fonctionnement a permis d'elaborer, a travers les bilans matieres et thermiques, un modele thermodynamique reliant les temperatures, les debits et les fractions massiques dans les differents compartiments. Des journees ensoleillees representatives des quatre saisons de l'annee ont ete considerees. Les variations du taux d'ensoleillement, des temperatures et des concentrations ont ete explorees. Les resultats ont montre, moyennant les hypotheses adoptees en particulier a pression de fonctionnement constante, que la demarche proposee a permis d'avoir une temperature de generation autour de 135 C et une temperature de condensation de 60 C. Ces temperatures sont atteinte par l'adaptation de la convection naturelle a l'air pour le fonctionnement du condenseur. (orig.)

  2. 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.

  3. 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.

  4. Industrial refrigeration by absorption/compression; Refrigeracion industrial por absorcion/compresion

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Delgado, Ramon; Heard, Christopher Lionel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The use of the absorption/compression refrigeration in the industrial area is analyzed. It is estimated than in Mexico 50% of the food is wasted for lack of refrigeration in the producing centers and by the inefficient distribution system, as well as for the hot climate. The functioning of the absorption refrigeration and the hybrid system absorption/compression which can operate with the two thermodynamic cycles in variable proportions, depending on the specific application, looking for operational advantages and energy efficiency is described. This type of technology could be applied in Mexico due to the lack of industrial refrigeration and to the need of substituting compressors in some companies which have up to 20 years of use [Espanol] Se analiza el uso de la refrigeracion por absorcion/compresion en el area industrial. En Mexico se estima que se desperdicia el 50% de los alimentos por falta de refrigeracion en los centros productores y por el deficiente sistema de distribucion, asi como por el clima calido. Se describe el funcionamiento de la refrigeracion por absorcion y la refrigeracion por absorcion/compresion o sistema hibrido, el cual puede funcionar con los dos tipos de ciclos termodinamicos, en proporciones variables, dependiendo de la aplicacion especifica, buscando ventajas de operacion y eficiencia energetica. Este tipo de tecnologia podria aplicarse en Mexico debido a la falta de refrigeracion industrial y a la necesidad de sustituir compresores en algunas empresas los cuales tienen hasta 20 anos de uso

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Performance of Gas Purge System of Absorption Refrigerating Machine

    Science.gov (United States)

    Kunugi, Yoshifumi; Ouchi, Tomihisa; Usui, Sanpei; Sugimoto, Shigeo

    Experimental studies on performance of two gas purge systems for the lithium bromide-water absorption refrigerating machine are presented in this paper. The first purge system is that the solution flow entrains the incondensable gas from the absorber in the first purge chamber, then the incondesable gas from the condenser in the second purge chamber. The second purge system is that the solution flow entrains the incondensable gas, separates it in the separator, and then returns to the refrigerating machine through the inverted U tube. As a result, purged gas rate of both gas purge systems conforms to the theoretical equation ; S=V0(P-P0), where S is purged gas rate, V0 is exhaust gas rate, P is pressure of purge chamber, and P0 is saturated vapor pressure of solution.

  10. 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.

  11. A Dynamic Model of a Vapor Compression Refrigeration Cycle using Zeotropic Refrigerant Mixtures

    Science.gov (United States)

    Unezaki, Fumitake; Matsuoka, Fumio

    In order to prove the effectiveness of the developed model, reported in the first report, about dynamics of a vapor compression refrigeration cycle with zeotropic refrigerant mixtures, simulation results are compared with the experimental results obtained for R-407C (R-32/R-125/R-134a=23/25/52wt%).The simulation results are consistent well with the experimental results. As a result of the numerical analysis of dynamic characteristics of composition changing, the variation of compositions in the refrigeration cycle is caused by the variation of the existing compositions of accumulator. The time constant of the composition is approximately equal to the time constant of the pressure and the mass distribution.

  12. 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.

  13. Extending the market for cogeneration with absorption refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Langreck, J. [Colibri, Vaals (Netherlands); Pruiksma, E. [Stork Thermeq, Hengelo (Netherlands)

    1999-07-01

    The use of heat generated by cogeneration plants for absorption refrigeration plants (ARPs) is discussed in this article, and the advantages of the combination of cogeneration and ARPs are reported. Details are given of the two different types of ARPs, its operation, the importance of the food industry and industries that need cooling as a market for ARP, and recent cogeneration-ARP systems such as that installed in a margarine production plant in Rotterdam. The use of the fluegases from cogeneration plants and heat flows from chemical plants to drive ARPs are considered. (UK)

  14. Simulator for design absorption refrigeration system; Simulador para projeto de ciclos de refrigeracao por absorcao

    Energy Technology Data Exchange (ETDEWEB)

    Morejon, C.F.M.; Brum, N. de C. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Mecanica]. E-mails: Camilo_freddy@hotmail.com; Nisio@serv.com.ufrj.br

    2000-07-01

    This work presents a development of a thermal fluid dynamics model and a solution of a steady state absorption refrigeration cycle, with ammonia water as the working fluid. Analytical thermodynamics models expressing the enthalpy in function of pressure, temperature and composition (h=f(P,T,x)), are used with the aim to design all of the cycle devices, moved by any type of energy such as solar, natural gas, steam or electrical energy (Morejon and Hackenberg, 1978). The development of the analysis is carried out by the application of thermal fluid dynamics concepts together with a detailed study of the heat and mass transfer in the different cycle stages. The thermodynamic cycle model, obtained from equation of state for ammonia - water mixtures (Ziegker and Trepp, 1984), is represented by the relation h - x (enthalpy-composition) for different pressures and temperatures. The obtained models are used to implement computational codes in MAPLE-V facilitating the design and simulation of refrigeration system. This study can be applied in the systems of air conditioning and refrigeration chambers design. (author)

  15. A Method to Predict the Composition of Zeotropic Refrigerant Mixtures Circulating in a Refrigeration Cycle

    Science.gov (United States)

    Sumida, Yoshihiro; Okazaki, Takashi; Tanaka, Naoki

    A theoretical analysis is developed to predict the composition of zeotropic refrigerant mixtures circulating in a refrigeration cycle. The composition is calculated by considering the composition distribution in the cycle and mass conservation of the each component of the mixtures. The composition distribution in the gas-liquid two phase region is calculated with an assumption of local equilibrium in each phase. The predicted compositions are also compared with experimental results, which are obtained for R-407C (23wt% R-32/25wt% R-125/52wt% R-134a). The theoretical analysis shows that the composition distributions of the more volatile components, R-32 and R-125, in the two-phase regions are lower than the initial1y charged compositions. As a result, the circulating fractions of R-32 and R-125 are slightly larger than the charged fractions when appropriate amount of refrigerant is charged in the cycle. This difference increases with addition of more refrigerants, which results in the presence of liquid in the accumulator. The theoretical analysis shows good agreement with the experimental results.

  16. 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

  17. 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.

  18. Evaluation of Enthalpy Diagrams for NH3-H2O Absorption Refrigerator

    Science.gov (United States)

    Takei, Toshitaka; Saito, Kiyoshi; Kawai, Sunao

    The protection of environment is becoming a grave problem nowadays and an absorption refrigerator, which does not use fleon as a refrigerant, is acquiring a close attention. Among the absorption refrigerators, a number of ammonia-water absorption refrigerators are being used in realm such as refrigeration and ice accumulation, since this type of refrigerator can produce below zero degree products. It is essential to conduct an investigation on the characteristics of ammonia-water absorption refrigerator in detail by means of computer simulation in order to realize low cost, highly efficient operation. Unfortunately, there have been number of problems in order to conduct computer simulations. Firstly, Merkel's achievements of enthalpy diagram does not give the relational equations. And secondly, although relational equation are being proposed by Ziegler, simpler equations that can be applied to computer simulation are yet to be proposed. In this research, simper equations based on Ziegler's equations have been derived to make computer simulation concerning the performance of ammonia-water absorption refrigerator possible-Both results of computer simulations using simple equations and Merkel's enthalpy diagram respectively, have been compared with the actual experimental data of one staged ammonia-water absorption refrigerator. Consequently, it is clarified that the results from Ziegler's equations agree with experimental data better than those from Merkel's enthalpy diagram.

  19. Solar Absorption Refrigeration System for Air-Conditioning of a Classroom Building in Northern India

    Science.gov (United States)

    Agrawal, Tanmay; Varun; Kumar, Anoop

    2015-10-01

    Air-conditioning is a basic tool to provide human thermal comfort in a building space. The primary aim of the present work is to design an air-conditioning system based on vapour absorption cycle that utilizes a renewable energy source for its operation. The building under consideration is a classroom of dimensions 18.5 m × 13 m × 4.5 m located in Hamirpur district of Himachal Pradesh in India. For this purpose, cooling load of the building was calculated first by using cooling load temperature difference method to estimate cooling capacity of the air-conditioning system. Coefficient of performance of the refrigeration system was computed for various values of strong and weak solution concentration. In this work, a solar collector is also designed to provide required amount of heat energy by the absorption system. This heat energy is taken from solar energy which makes this system eco-friendly and sustainable. A computer program was written in MATLAB to calculate the design parameters. Results were obtained for various values of solution concentrations throughout the year. Cost analysis has also been carried out to compare absorption refrigeration system with conventional vapour compression cycle based air-conditioners.

  20. Parametric optimum design of an irreversible spin quantum refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    Lin Bi-Hong; Chen Jin-Can

    2005-01-01

    The general performance characteristics of an irreversible quantum refrigeration cycle using many non-interacting spin-1/2 systems as the working substance and consisting of two adiabatic and two isomagnetic field processes are investigated, based on the quantum master equation and semi-group approach. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to the finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of the temperatures of the working substance and the times spent on the two isomagnetic field processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is also analysed in detail. The results obtained here are further generalized, so that they may be directly used to describe the performance of the quantum refrigeration cycle using spin-J systems as the working substance.

  1. Water- Lithium Bromide-γ- Butyrolactone Absorption Refrigerating Machine

    Science.gov (United States)

    Iyoki, Shigeki; Uemura, Tadashi

    This investigation was carried out in order to find corrosion inhibitors which would be effective in controlling the corrosion for the water-lithium bromide-γ-butyrolactone (20 moles water/1 mole γ-butyrolactone) absorption refrigerating machine. The experiments were carried out on continuous boiling test, intermittent boiling test and galvanic corrosion test with the use of organic inhibitors and inorganic inhibitors in γ-butyrolactone aqueous solution of lithium bromide. The metals used in these corrosion tests were mainly SS 41 and copper. From these experimental results, the most suitable corrosion inhibitors for SS 41 and copper in γ-butyrolactone aqueous solution of lithium bromide Were recognized to be benzotriazole, tolyltriazole and lithium molybdate.

  2. Ammonia-water absorption refrigeration systems with flooded evaporators

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Sieres, Jaime [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Vigo, Campus Lagoas-Marcosende No. 9, 36310 Vigo (Spain)

    2006-12-15

    The harmful effects of water accumulation in the evaporator in ammonia-water absorption refrigeration systems (AARS) with flooded evaporators are a crucial issue. In this paper, the effects of the ammonia purification and the liquid entrainment and blow-down from the evaporator in AARS are analyzed. A mathematical model based on a single stage system with complete condensation has been developed. The ammonia purification is evaluated by means of the Murphree efficiencies of the stripping and rectifying sections of the distillation column. The entrainment and blow-down are taking into account considering the corresponding flow rates as a fraction of the dry vapour at the evaporator outlet. The influence of the distillation column components efficiency on the attainable distillate concentration and the effects of the distillate concentration and the liquid entrainment and blow-down on the system operating conditions and performance are analyzed and quantified. If no liquid entrainment or blow-down is considered, very high efficiencies in the distillation column are required. Small values of liquid entrainment or blow-down fractions increase significantly the operating range of the absorption system. If high values of the blow-down fraction are required, then a heat exchanger should be added to the system in order to recover the refrigeration capacity of the blow-down by additional subcooling of the liquid from the condenser. For a fixed value of the distillation column efficiency, an optimum value of the liquid blow-down fraction exists. Moreover, an optimum combination of generation temperature, reflux ratio and blow-down fraction can be found, which should be considered in designing and controlling an AARS. (author)

  3. Refrigeration cycle for cryogenic separation of hydrogen from coke oven gas

    Institute of Scientific and Technical Information of China (English)

    Kun CHANG; Qing LI; Qiang LI

    2008-01-01

    Ten billion cubic meters of hydrogen are dissip-ated to the environment along with the emission of coke-oven gas every year in China. A novel cryogenic separation of hydrogen from coke oven gas is proposed to separate the hydrogen and liquefy it simultaneously, and the cooling capacity is supplied by two refrigeration cycles. The perform-ance of the ideal vapor refrigeration cycle is analyzed with methane and nitrogen as refrigerant respectively. The results show that the coefficient of performance (COP) of methane refrigeration cycle is 2.7 times that of nitrogen refrigeration cycle, and the figure of merit (FOM) of methane refrigera-tion cycle is 1.6 times that of nitrogen refrigeration cycle. The performance of ideal gas refrigeration cycle is also analyzed with neon, hydrogen and helium as refrigerant respectively. The results show that both the coefficient of performance and figure of merit of neon refrigeration cycle is the highest. It is thermodynamically possible to arrange the refrigeration cycle with methane and neon as refrigerant, respectively.

  4. Theoretical Study on CO2 Transcritical Cycle Combined Ejector Cycle Refrigeration System

    Institute of Scientific and Technical Information of China (English)

    卢苇; 马一太; 李敏霞; 查世彤

    2003-01-01

    Chlorofluorocarbons(CFCs) or hydrochlorofluorocarbons(HCFCs) are as main refrigerants used in traditional refrigeration systems driven by electricity from burning fossil fuels, which is regarded as one of the major reasons for ozone depletion (man-made refrigerants emission) and global warming (CO2 emission). So people pay more and more attention to natural refrigerants and energy saving technologies. An innovative system combining CO2 transcritical cycle with ejector cycle is proposed in this paper. The CO2 compression sub-cycle is powered by electricity with the characteristics of relatively high temperature in the gas cooler (defined as an intercooler by the proposed system). In order to recover the waste heat, an ejector sub-cycle operating with the natural refrigerants (NH3, H2O) is employed. The two sub-cycles are connected by an intercooler. This combined cycle joins the advantages of the two cycles together and eliminates the disadvantages. The influences of the evaporation temperature in CO2 compression sub-cycle, the evaporation temperature in the ejector sub-cycle, the temperature in the intercooler and the condensation temperature in the proposed system performance are discussed theoretically in this study. In addition, some unique features of the system are presented.

  5. New Regenerative Cycle for Vapor Compression Refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Bergander, Mark J [Magnetic Development, Inc.; Butrymowicz, Dariusz [Polish Academy of Scinces

    2010-01-26

    This project was a continuation of Category 1 project, completed in August 2005. Following the successful bench model demonstration of the technical feasibility and economic viability, the main objective in this stage was to fabricate the prototype of the heat pump, working on the new thermodynamic cycle. This required further research to increase the system efficiency to the level consistent with theoretical analysis of the cycle. Another group of objectives was to provide the foundation for commercialization and included documentation of the manufacturing process, preparing the business plan, organizing sales network and raising the private capital necessary to acquire production facilities.

  6. Development of Low Global Warming Potential Refrigerant Solutions for Commercial Refrigeration Systems using a Life Cycle Climate Performance Design Tool

    Energy Technology Data Exchange (ETDEWEB)

    Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Vineyard, Edward Allan [ORNL

    2012-01-01

    Commercial refrigeration systems are known to be prone to high leak rates and to consume large amounts of electricity. As such, direct emissions related to refrigerant leakage and indirect emissions resulting from primary energy consumption contribute greatly to their Life Cycle Climate Performance (LCCP). In this paper, an LCCP design tool is used to evaluate the performance of a typical commercial refrigeration system with alternative refrigerants and minor system modifications to provide lower Global Warming Potential (GWP) refrigerant solutions with improved LCCP compared to baseline systems. The LCCP design tool accounts for system performance, ambient temperature, and system load; system performance is evaluated using a validated vapor compression system simulation tool while ambient temperature and system load are devised from a widely used building energy modeling tool (EnergyPlus). The LCCP design tool also accounts for the change in hourly electricity emission rate to yield an accurate prediction of indirect emissions. The analysis shows that conventional commercial refrigeration system life cycle emissions are largely due to direct emissions associated with refrigerant leaks and that system efficiency plays a smaller role in the LCCP. However, as a transition occurs to low GWP refrigerants, the indirect emissions become more relevant. Low GWP refrigerants may not be suitable for drop-in replacements in conventional commercial refrigeration systems; however some mixtures may be introduced as transitional drop-in replacements. These transitional refrigerants have a significantly lower GWP than baseline refrigerants and as such, improved LCCP. The paper concludes with a brief discussion on the tradeoffs between refrigerant GWP, efficiency and capacity.

  7. 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

  8. Analysis of Transient Behavior of a Vapor Compression Refrigeration Cycle

    Science.gov (United States)

    Fukushima, Toshihiko; Miyamoto, Seigo

    A mathematical model for a vapor compression refrigeration cycle for automotive air conditioner is developed, which basically consists of compressor, condenser, receiver, expansion valve, evaporator, suction pressure control valve and piping. The main purpose of this model is to provide the designer with a tool for improving cooling capacity and investigating capacity control of the refrigeration cycle at transient conditions. A lumped parameter system is used for the mathematical model of the condenser and the evaporator, that is obtained with volume integral of the equation of continuity and energy over a bounded volume region. The compressor model and the piping models are also lumped parameter systems, and heat capacity of their walls are taken into account. The theoretical solutions of this model are in good agreement with the experimental results.

  9. Gas Vapor Injection on Refrigerant Cycle Using Piston Technology

    OpenAIRE

    Colmek, Sophie; Goderneaux, Laurent

    2012-01-01

    Gas vapor injection on refrigerant cycle is always used with Scroll, Rotary or others compressors technology to improve efficiency of the system at low and high ambient temperatures. Probably this kind of compressor is more adapted than the piston technology owing to their mechanical system. In this paper, we present the challenge of vapor injection realized on piston technology compressor range non for improving the cooling capacity of the system but to maintain the compressor temperature in...

  10. Mathematical Model of a Lithium-Bromide/Water Absorption Refrigeration System Equipped with an Adiabatic Absorber

    Directory of Open Access Journals (Sweden)

    Salem M. Osta-Omar

    2016-11-01

    Full Text Available The objective of this paper is to develop a mathematical model for thermodynamic analysis of an absorption refrigeration system equipped with an adiabatic absorber using a lithium-bromide/water (LiBr/water pair as the working fluid. The working temperature of the generator, adiabatic absorber, condenser, evaporator, the cooling capacity of the system, and the ratio of the solution mass flow rate at the circulation pump to that at the solution pump are used as input data. The model evaluates the thermodynamic properties of all state points, the heat transfer in each component, the various mass flow rates, and the coefficient of performance (COP of the cycle. The results are used to investigate the effect of key parameters on the overall performance of the system. For instance, increasing the generator temperatures and decreasing the adiabatic absorber temperatures can increase the COP of the cycle. The results of this mathematical model can be used for designing and sizing new LiBr/water absorption refrigeration systems equipped with an adiabatic absorber or for optimizing existing aforementioned systems.

  11. A LiBr-H2O Absorption Refrigerator Incorporating a Thermally Activated Solution Pumping Mechanism

    Directory of Open Access Journals (Sweden)

    Ian W. Eames

    2017-02-01

    Full Text Available This paper provides an illustrated description of a proposed LiBr-H2O vapour absorption refrigerator which uses a thermally activated solution pumping mechanism that combines controlled variations in generator vapour pressure with changes it produces in static-head pressure difference to circulate the absorbent solution between the generator and absorber vessels. The proposed system is different and potentially more efficient than a bubble pump system previously proposed and avoids the need for an electrically powered circulation pump found in most conventional LiBr absorption refrigerators. The paper goes on to provide a sample set of calculations that show that the coefficient of performance values of the proposed cycle are similar to those found for conventional cycles. The theoretical results compare favourably with some preliminary experimental results, which are also presented for the first time in this paper. The paper ends by proposing an outline design for an innovative steam valve, which is a key component needed to control the solution pumping mechanism.

  12. Performance of a new refrigeration cycle using refrigerant mixture R32/R134a for residential air-conditioner applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianyong; Yu, Jianlin [Department of Refrigeration and Cryogenic Engineering, School of Energy and Power Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2008-07-01

    In this paper, a new refrigeration cycle (NRC) using the binary non-azeotropic refrigerant mixture R32/R134a is presented, which can be an alternative refrigeration cycle applied in residential air-conditioner. In the NRC, refrigerant circuit of the evaporator is separated into two branches. Because the non-azeotropic mixture has the characteristic of temperature glide, an important benefit of such configuration is that the Lorentz cycle can be realized. Compared with that of conventional cycle configuration, the new cycle efficiency can be improved. The calculating results show that, in the conventional refrigeration cycle (CRC), the mixture R32/R134a has a close performance to that is obtainable with pure refrigerant R22. However, the mixture R32/R134a in the NRC will result in a better performance. The maximal COP can be improved in a range of 8-9% over that of the CRC, and the volumetric refrigerating capacity can be approximately increased by 9.5%. (author)

  13. Cycle Analysis using Exhaust Heat of SOFC and Turbine Combined Cycle by Absorption Chiller

    Science.gov (United States)

    Takezawa, Shinya; Wakahara, Kenji; Araki, Takuto; Onda, Kazuo; Nagata, Susumu

    A power generating efficiency of solid oxide fuel cell (SOFC) and gas turbine combined cycle is fairly high. However, the exhaust gas temperature of the combined cycle is still high, about 300°C. So it should be recovered for energy saving, for example, by absorption chiller. The energy demand for refrigeration cooling is recently increasing year by year in Japan. Then, we propose here a cogeneration system by series connection of SOFC, gas turbine and LiBr absorption chiller to convert the exhaust heat to the cooling heat. As a result of cycle analysis of the combined system with 500kW class SOFC, the bottoming single-effect absorption chiller can produce the refrigerating capacity of about 120kW, and the double-effect absorption chiller can produce a little higher refrigerating capacity of about 130kW without any additional fuel. But the double-effect absorption chiller became more expensive and complex than the single-effect chiller.

  14. Computational Evaluation of Mixtures of Hydrofluorocarbons and Deep Eutectic Solvents for Absorption Refrigeration Systems.

    Science.gov (United States)

    Abedin, Rubaiyet; Heidarian, Sharareh; Flake, John C; Hung, Francisco R

    2017-08-24

    We used computational tools to evaluate three working fluid mixtures for single-effect absorption refrigeration systems, where the generator (desorber) is powered by waste or solar heat. The mixtures studied here resulted from combining a widely used hydrofluorocarbon (HFC) refrigerant, R134a, with three common deep eutectic solvents (DESs) formed by mixing choline chloride (hydrogen bond acceptor, HBA) with urea, glycerol, or ethylene glycol as the hydrogen bond donor (HBD) species. The COSMOtherm/TmoleX software package was used in combination with refrigerant data from NIST/REFPROP, to perform a thermodynamic evaluation of absorption refrigeration cycles using the proposed working fluid mixtures. Afterward, classical MD simulations of the three mixtures were performed to gain insight on these systems at the molecular level. Larger cycle efficiencies are obtained when R134a is combined with choline chloride and ethylene glycol, followed by the system where glycerol is the HBD, and finally that where the HBD is urea. MD simulations indicate that the local density profiles of all species exhibit very sharp variations in systems containing glycerol or urea; furthermore, the Henry's law constants of R134a in these two systems are larger than those observed for the HFC in choline chloride and ethylene glycol, indicating that R134a is more soluble in the latter DES. Interaction energies indicate that the R134a-R134a interactions are weaker in the system where ethylene glycol is the HBD, as compared to in the other DES. Radial distribution functions confirm that in all systems, the DES species do not form strong directional interactions (e.g., hydrogen bonds) with the R134a molecules. Relatively strong interactions are observed between the Cl anions and the hydrogen atoms in R134a; however, the atom-atom interactions between R134a and the cation and HBD species are weaker and do not play a significant role in the solvation of the refrigerant. In all systems, R134a has

  15. Computational tool for simulation of power and refrigeration cycles

    Science.gov (United States)

    Córdoba Tuta, E.; Reyes Orozco, M.

    2016-07-01

    Small improvement in thermal efficiency of power cycles brings huge cost savings in the production of electricity, for that reason have a tool for simulation of power cycles allows modeling the optimal changes for a best performance. There is also a big boom in research Organic Rankine Cycle (ORC), which aims to get electricity at low power through cogeneration, in which the working fluid is usually a refrigerant. A tool to design the elements of an ORC cycle and the selection of the working fluid would be helpful, because sources of heat from cogeneration are very different and in each case would be a custom design. In this work the development of a multiplatform software for the simulation of power cycles and refrigeration, which was implemented in the C ++ language and includes a graphical interface which was developed using multiplatform environment Qt and runs on operating systems Windows and Linux. The tool allows the design of custom power cycles, selection the type of fluid (thermodynamic properties are calculated through CoolProp library), calculate the plant efficiency, identify the fractions of flow in each branch and finally generates a report very educational in pdf format via the LaTeX tool.

  16. Using engine exhaust gas as energy source for an absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Manzela, Andre Aleixo [PETROBRAS, Exploration and Production, Av. Rui Barbosa, 1940 - 3 andar, 27915-012 - Macae - RJ (Brazil); Hanriot, Sergio Morais; Cabezas-Gomez, Luben; Sodre, Jose Ricardo [Pontifical Catholic University of Minas Gerais, Department of Mechanical Engineering, Av. Dom Jose Gaspar, 500, 30535-610 - Belo Horizonte - MG (Brazil)

    2010-04-15

    This work presents an experimental study of an ammonia-water absorption refrigeration system using the exhaust of an internal combustion engine as energy source. The exhaust gas energy availability and the impact of the absorption refrigeration system on engine performance, exhaust emissions, and power economy are evaluated. A production automotive engine was tested in a bench test dynamometer, with the absorption refrigeration system adapted to the exhaust pipe. The engine was tested for 25%, 50%, 75% and wide-open throttle valve. The refrigerator reached a steady state temperature between 4 and 13 C about 3 h after system start up, depending on engine throttle valve opening. The calculated exhaust gas energy availability suggests the cooling capacity can be highly improved for a dedicated system. Exhaust hydrocarbon emissions were higher when the refrigeration system was installed in the engine exhaust, but carbon monoxide emissions were reduced, while carbon dioxide concentration remained practically unaltered. (author)

  17. 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.

  18. Study of optimal discharge pressure of compressor in CO_2 refrigerating trans-critical cycle

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, a carbon dioxide trans-critical refrigerating system which is different from a conventional subcritical refrigerating cycle was studied. The trans-critical carbon dioxide refrigerating systems are based on the Gustav Lorntzen cycle. Emphasis was focused on how to determine the optimal discharge pressure of compressor in CO2 trans-critical cycle. The factors related with the optimal discharge pressure were analyzed. A formula was developed based on cycle simulation, which could be used to pred...

  19. Control structure selection for vapor compression refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xiaohong; Li, Shaoyuan [Shanghai Jiao Tong Univ., Shanghai (China). Dept. of Automation; Shandong Jianzhu Univ., Jinan (China). School of Information and Electrical Engineering; Cai, Wenjian; Ding, Xudong [Nanyang Technological Univ., Singapore (Singapore). School of Electrical and Electronic Engineering

    2013-07-01

    A control structure selection criterion which can be used to evaluate the control performance of different control structures for the vapor compression refrigeration cycle is proposed in this paper. The calculation results of the proposed criterion based on the different reduction models are utilized to determine the optimized control model structure. The effectiveness of the criterion is verified by the control effects of the model predictive control (MPC) controllers which are designed based on different model structures. The response of the different controllers applied on the actual vapor compression refrigeration system indicate that the best model structure is in consistent with the one obtained by the proposed structure selection criterion which is a trade-off between computation complexity and control performance.

  20. Industrial ammonia absorption refrigeration plants in combination with gas engines; Groupes de refrigeration industriels a absorption d'ammoniac combines avec des moteurs a gaz

    Energy Technology Data Exchange (ETDEWEB)

    Bassols, J. [Colibri bv (Netherlands); Sahu, J. [Gas Natural SDG, S.A. (Spain)

    2000-07-01

    In many industrial sectors, co-generation systems with gas turbines or engines and ammonia absorption refrigeration plants are being introduced for the simultaneous production of electricity and refrigeration in order to meet the energy requirements inherent to each process and to reduce the operating costs. The different possibilities to link the absorption refrigeration plant to the cogeneration system and to the consumers are described. Different examples of realised projects are used to illustrate the different systems. Despite the fact that, compared to compression refrigeration machines, ARP's have lower COP (coefficient of performance) and higher investment costs, the advantage of using thermal energy as a driving energy instead of electricity makes the combination cogeneration-ARP very attractive. The plants can easily be integrated into an existing refrigeration installation. The full automatic control systems provide a trouble-free operation. Because most of the components of an ARP are heat exchangers, the plants only need little maintenance and are not susceptible to trouble. For their maintenance, no special knowledge is necessary. Plants working with NH{sub 3}-H{sub 2}O use ammonia as a refrigerant, which is a natural and environment-friendly fluid. (authors)

  1. An active thermal compensator for closed-cycle helium refrigerators

    Science.gov (United States)

    Jennings, D. E.; Hillman, J. J.

    1977-01-01

    A technique was developed for reducing the amplitude of the temperature oscillation in He closed-cyle refrigerators. The device uses a semiconductor diode as a heating element to actively supply a small oscillating input of heat at a point between the laser and the cold-tip to cancel the heat oscillations due to the refrigerator. It was found that the heater diode could drive the temperature of the heat sink more effectively, i.e., with lower current and therefore less heat, if the heat sink was insulated slightly from the rest of the mount. A sine-wave generator was used to drive the programmable supply which provided the offset current to the heater diode. By matching the frequency and phase of the oscillator to that of the refrigerator cycle, and by adjusting the amplitude of the oscillator signal, the temperature fluctuations at the laser could be minimized. Residual fluctuations were about 0.003K peak-to-peak, at an operating temperature of 9.5K.

  2. 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。

  3. 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.)

  4. Exergy analysis of vapor compression refrigeration cycle with two-stage and intercooler

    Science.gov (United States)

    Kılıç, Bayram

    2012-07-01

    In this study, exergy analyses of vapor compression refrigeration cycle with two-stage and intercooler using refrigerants R507, R407c, R404a were carried out. The necessary thermodynamic values for analyses were calculated by Solkane program. The coefficient of performance, exergetic efficiency and total irreversibility rate of the system in the different operating conditions for these refrigerants were investigated. The coefficient of performance, exergetic efficiency and total irreversibility rate for alternative refrigerants were compared.

  5. Exergy analysis of vapor compression refrigeration cycle with two-stage and intercooler

    Energy Technology Data Exchange (ETDEWEB)

    Kilic, Bayram [Mehmet Akif Ersoy University, Bucak Emin Guelmez Vocational School, Bucak, Burdur (Turkey)

    2012-07-15

    In this study, exergy analyses of vapor compression refrigeration cycle with two-stage and intercooler using refrigerants R507, R407c, R404a were carried out. The necessary thermodynamic values for analyses were calculated by Solkane program. The coefficient of performance, exergetic efficiency and total irreversibility rate of the system in the different operating conditions for these refrigerants were investigated. The coefficient of performance, exergetic efficiency and total irreversibility rate for alternative refrigerants were compared. (orig.)

  6. Frequency Response Adaptive Control of a Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Jens G. Balchen

    1989-01-01

    Full Text Available A technique for the adaptation of controller parameters in a single control loop based upon the estimation of frequency response parameters has been presented in an earlier paper. This paper contains an extension and a generalization of the first method and results in a more versatile solution which is applicable to a wider range of process characteristics. The application of this adaptive control technique is illustrated by a laboratory refrigeration cycle in which the evaporator pressure controls the speed of the compressor.

  7. Experimental investigation of the ecological hybrid refrigeration cycle

    Science.gov (United States)

    Cyklis, Piotr; Kantor, Ryszard; Ryncarz, Tomasz; Górski, Bogusław; Duda, Roman

    2014-09-01

    The requirements for environmentally friendly refrigerants promote application of CO2 and water as working fluids. However there are two problems related to that, namely high temperature limit for CO2 in condenser due to the low critical temperature, and low temperature limit for water being the result of high triple point temperature. This can be avoided by application of the hybrid adsorption-compression system, where water is the working fluid in the adsorption high temperature cycle used to cool down the CO2 compression cycle condenser. The adsorption process is powered with a low temperature renewable heat source as solar collectors or other waste heat source. The refrigeration system integrating adsorption and compression system has been designed and constructed in the Laboratory of Thermodynamics and Thermal Machine Measurements of Cracow University of Technology. The heat source for adsorption system consists of 16 tube tulbular collectors. The CO2 compression low temperature cycle is based on two parallel compressors with frequency inverter. Energy efficiency and TEWI of this hybrid system is quite promising in comparison with the compression only systems.

  8. Experimental investigation of the ecological hybrid refrigeration cycle

    Directory of Open Access Journals (Sweden)

    Cyklis Piotr

    2014-09-01

    Full Text Available The requirements for environmentally friendly refrigerants promote application of CO2 and water as working fluids. However there are two problems related to that, namely high temperature limit for CO2 in condenser due to the low critical temperature, and low temperature limit for water being the result of high triple point temperature. This can be avoided by application of the hybrid adsorption-compression system, where water is the working fluid in the adsorption high temperature cycle used to cool down the CO2 compression cycle condenser. The adsorption process is powered with a low temperature renewable heat source as solar collectors or other waste heat source. The refrigeration system integrating adsorption and compression system has been designed and constructed in the Laboratory of Thermodynamics and Thermal Machine Measurements of Cracow University of Technology. The heat source for adsorption system consists of 16 tube tulbular collectors. The CO2 compression low temperature cycle is based on two parallel compressors with frequency inverter. Energy efficiency and TEWI of this hybrid system is quite promising in comparison with the compression only systems.

  9. 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.

  10. Cycle Simulation of HotWater Fired Absorption Chiller

    Science.gov (United States)

    Esaki, Shuji; Iramina, Kazuyasu; Kobayashi, Takahiro; Ohnou, Masayuki; Kaneko, Toshiyuki; Soga, Takashi

    The design limits were examined to determine the lowest temperature for hot water that can be used as a heat source to drive a hot water fired absorption chiller. Advantage was taken of the fact that the cycle calculation method using the minimum temperature difference is quite effective. This minimum temperature difference was the lower of the two temperature differences used to get the logarithmic mean temperature difference that need to design the evaporator, absorber, condenser and generator in an absorption refrigerator. This report proposes a new solution algorithm employing this minimum temperature difference to make a cycle simulation of the hot water fired absorption chiller. It shows the lowest usable temperature for hot water and makes clear the chilled water and cooling water temperature conditions that can provide the lowest temperature.

  11. A closed-cycle 1 K refrigeration cryostat

    Science.gov (United States)

    Wang, Chao; Lichtenwalter, Ben; Friebel, Aaron; Tang, Hong X.

    2014-11-01

    A 1 K closed-cycle cryostat has been developed to provide continuous cooling to a photon detector below 2 K. A two-stage 4 K pulse tube cryocooler is used to liquefy evacuated vapor from a 1 K pumping port to form a closed-cycle refrigeration loop. A 1 K instrumentation chamber, attached to the 1 K cooling station, is designed to operate with helium inside and provide more uniform cooling. The design of the cryostat has no direct mechanical contact between the pulse tube cryocooler heat exchangers and the 1 K cooling station resulting in almost no vibration transfer to instrumentation chamber. The cryostat can reach a no-load temperature of 1.62 K and provide 250 mW cooling power at 1.84 K.

  12. A new technology for fishing vessels: the use of ejector expansion refrigeration cycle

    Science.gov (United States)

    Memet, Feiza; Mitu, Daniela Elena

    2015-02-01

    A challenge that fishing industry is facing is the improvement of the refrigeration technology on board of fishing vessels. This paper deals with vapor compression refrigeration systems included on board of these ships. In these systems, significant thermodynamic losses are encountered in the expansion valve, during throttling process. Because it is possible to improve a thermodynamic process by decreasing irreversibility, in this paper it is used an ejector in order to reduce throttling irreversibility. A new technology results, the use of an ejector as a refrigerant expander leading to the ejector expansion refrigeration cycle. The theoretical study developed here will reveal a performance improvement of the new cycle. Also, because the traditional refrigerant used in marine refrigeration is R 134a, which presents a high value of its Global Warming Potential, the performance analysis is extended for the case of the use of other more environmentally friendly refrigerants: propane and isobutane.

  13. Compression-absorption (resorption) refrigerating machinery. Modeling of reactors; Machine frigorifique a compression-absorption (resorption). Modelisation des reacteurs

    Energy Technology Data Exchange (ETDEWEB)

    Lottin, O.; Feidt, M.; Benelmir, R. [LEMTA-UHP Nancy-1, 54 - Vandoeuvre-les-Nancy (France)

    1997-12-31

    This paper is a series of transparencies presenting a comparative study of the thermal performances of different types of refrigerating machineries: di-thermal with vapor compression, tri-thermal with moto-compressor, with ejector, with free piston, adsorption-type, resorption-type, absorption-type, compression-absorption-type. A prototype of ammonia-water compression-absorption heat pump is presented and modeled. (J.S.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Corbaz, C.; Utz, C.

    2005-07-01

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

  15. First Law Analysis of a Two-stage Ejector-vapor Compression Refrigeration Cycle working with R404A

    National Research Council Canada - National Science Library

    Feiza Memet; Daniela-Elena Mitu

    2011-01-01

    The traditional two-stage vapor compression refrigeration cycle might be replaced by a two-stage ejector-vapor compression refrigeration cycle if it is aimed the decrease of irreversibility during expansion...

  16. High performance heat pump absorption cycles

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.; Longo, G.; Rossetto, L.

    1988-10-01

    Absorption heat pumps can provide high performances when operating in suitable cycles with multiple effects. This report describes some multistage cycles and evaluates the coefficient of performance realistically obtainable both in winter and summer working conditions.

  17. 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.

  18. Thermodynamic Analysis and Comparison on Low Temperature CO2-NH3 Cascade Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    查世彤; 马一太; 申江; 李敏霞

    2003-01-01

    This paper is focused on the cascade refrigeration cycle using natural refrigerant CO2-NH3. The properties of refrigerants CO2 and NH3 are introduced and analyzed.CO2 has the advantage in low stage of cascade refrigeration cycle due to its good characteristics and properties. The thermodynamic analysis results of the CO2-NH3 cascade refrigeration cycle demonstrates that the cycle has an optimum condensation temperature of low stage and also has an optimum flow rate ratio.By comparing with the R13-R22 and NH3-NH3 cascade refrigeration cycles, the mass flow rate ratio of CO2-NH3 is larger than those of R13-R22 and NH3-NH3, the theoretical COP of CO2-NH3 cascade refrigeration cycle is larger than that of the R13-R22 cascade cycle and smaller than that of the NH3-NH3 cascade cycle. But the real COP of CO2-NH3 cascade cycle will be higher than those of R13-R22 and NH3-NH3 because the specific volume of CO2 at low temperature does not change much and its dynamic viscosity is also small.

  19. 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..

  20. Refrigerator with variable capacity compressor and cycle priming action through capacity control and associated methods

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Alberto Regio; Litch, Andrew D.; Wu, Guolian

    2016-03-15

    A refrigerator appliance (and associated method) that includes a condenser, evaporator and a multi-capacity compressor. The appliance also includes a pressure reducing device arranged within an evaporator-condenser refrigerant circuit, and a valve system for directing or restricting refrigerant flow through the device. The appliance further includes a controller for operating the compressor upon the initiation of a compressor ON-cycle at a priming capacity above a nominal capacity for a predetermined or calculated duration.

  1. A thermodynamic review of cryogenic refrigeration cycles for liquefaction of natural gas

    Science.gov (United States)

    Chang, Ho-Myung

    2015-12-01

    A thermodynamic review is presented on cryogenic refrigeration cycles for the liquefaction process of natural gas. The main purpose of this review is to examine the thermodynamic structure of various cycles and provide a theoretical basis for selecting a cycle in accordance with different needs and design criteria. Based on existing or proposed liquefaction processes, sixteen ideal cycles are selected and the optimal conditions to achieve their best thermodynamic performance are investigated. The selected cycles include standard and modified versions of Joule-Thomson (JT) cycle, Brayton cycle, and their combined cycle with pure refrigerants (PR) or mixed refrigerants (MR). Full details of the cycles are presented and discussed in terms of FOM (figure of merit) and thermodynamic irreversibility. In addition, a new method of nomenclature is proposed to clearly identify the structure of cycles by abbreviation.

  2. The Use of Water Vapor as a Refrigerant: Impact of Cycle Modifications on Commercial Viability

    Energy Technology Data Exchange (ETDEWEB)

    Brandon F. Lachner, Jr.; Gregory F. Nellis; Douglas T. Reindl

    2004-08-30

    This project investigated the economic viability of using water as the refrigerant in a 1000-ton chiller application. The most attractive water cycle configuration was found to be a flash-intercooled, two-stage cycle using centrifugal compressors and direct contact heat exchangers. Component level models were developed that could be used to predict the size and performance of the compressors and heat exchangers in this cycle as well as in a baseline, R-134a refrigeration cycle consistent with chillers in use today. A survey of several chiller manufacturers provided information that was used to validate and refine these component models. The component models were integrated into cycle models that were subsequently used to investigate the life-cycle costs of both an R-134a and water refrigeration cycle. It was found that the first cost associated with the water as a refrigerant cycle greatly exceeded the savings in operating costs associated with its somewhat higher COP. Therefore, the water refrigeration cycle is not an economically attractive option to today's R-134a refrigeration system. There are a number of other issues, most notably the requirements associated with purging non-condensable gases that accumulate in a direct contact heat exchanger, which will further reduce the economic viability of the water cycle.

  3. FUZZY THERMOECONOMIC APPROACH TO NANOFLUID SELECTION IN VAPOR COMPRESSION REFRIGERATION CYCLE

    Directory of Open Access Journals (Sweden)

    D. Kuleshov

    2014-06-01

    Full Text Available The working fluid selection in the vapour compression refrigeration cycles has been studied as a fuzzy thermoeconomic optimization problem. Three criteria: thermodynamic (COP Coefficient Of Performance, economic (LCC Life Cycle Cost, and ecologic (GWP – Global Warming Potential are chosen as target functions. The decision variables X as an information characteristics of desired refrigerant are presented by its critical parameters and normal boiling temperature. Local criteria are expressed via thermodynamic properties restored from information characteristics of refrigerant X, as well as life cycle costs are calculated by the standard economic relationships. GWP values are taken from the refrigerant database. Class of substances under consideration is presented by the natural refrigerant R600a embedded with nanostructured materials.

  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. A closed cycle cascade Joule Thomson refrigerator for cooling Josephson junction magnetometers

    Science.gov (United States)

    Tward, E.; Sarwinski, R.

    1985-01-01

    A closed cycle cascade Joule Thomson refrigerator designed to cool Josephson Junction magnetometers to liquid helium temperature is being developed. The refrigerator incorporates 4 stages of cooling using the working fluids CF4 and He. The high pressure gases are provided by a small compressor designed for this purpose. The upper stages have been operated and performance will be described.

  6. Thermodynamic simulation of a rotating Ericsson-cycle magnetic refrigerator without a regenerator

    Science.gov (United States)

    Hakuraku, Y.

    1987-09-01

    A magnetic Ericsson cycle, which consists of two isothermal stages and two isofield stages, is generally thought to require regenerators. However, a new concept makes it possible to realize magnetic refrigerators capable of executing an Ericsson-cycle without using regenerators. The basic principle lies in directly linking the two isofield changes by transferring heat between the isofield stages through heat paths rather than through regenerators. A fundamental configuration is proposed for a rotating magnetic refrigerator that operates based on this concept. A simulation of the thermodynamic cycle in this simplified refrigerator model shows that the system is theoretically feasible.

  7. Prediction of refrigerant absorption and onset of natural convection in lubricant oil

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Jader R.; Marcelino Neto, Moises A. [Department of Mechanical Engineering, Federal University of Santa Catarina, Florianopolis, SC 88040900 (Brazil); Thoma, Stefan M. [Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology, Sonneggstrasse 3, 8092 Zurich (Switzerland)

    2008-11-15

    Refrigerant absorption and mixing in lubricant oil are important in the design of refrigeration compressors and refrigeration systems. Experimental work is reported on absorption of R-134a vapour through the top interface of an initially stagnant layer of pure lubricant oil. Since the liquid refrigerant is heavier than the oil, mixing is enhanced due to natural mass convection. In the present paper, the behaviour of the liquid temperature during absorption is described based on measurements carried out in a test rig consisting of a transparent 70 mm ID, 150 mm long, vertical glass tube through which absorption can be directly observed. Transient liquid temperatures were measured at three different heights in the test section (two in the vapour, one in the liquid). The experimental work is complemented by a theoretical analysis of the critical time for the onset of mass transfer induced Rayleigh instability. The model is based on a critical mass transfer Rayleigh number criterion widely reported in the literature and takes into account the variation of physical properties in the liquid layer. The critical time for the onset of natural mass convection increases with decreasing system pressure as a result of a lower equilibrium concentration at the vapour-liquid interface. (author)

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

    Science.gov (United States)

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

    2015-07-01

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

  9. Geothermal absorption refrigeration for food processing industries. Final report, December 13, 1976--November 13, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Harris, R.L.; Olson, G.K.; Mah, C.S.; Bujalski, J.H.

    1977-11-01

    The first step in the economic analysis of the integration of geothermally powered absorption refrigeration into a food processing plant was an evaluation of the potential geothermal sites in the Western United States. The evaluation covered availability of raw materials, transportation, adequate geothermal source, labor, and other requirements for food processing plants. Several attractive geothermal sites were identified--Raft River, Idaho; Sespe Hot Springs, California; Vale Hot Springs, Oregon; Weisler-Crane Creek, Idaho; Cosco Hot Springs, California; and the Imperial Valley, California. The most economically attractive food processing industry was then matched to the site based on its particular energy, raw material, and transportation requirements. The more promising food processors identified were for frozen potato or vegetable products, freeze-dried products, and meat processing. For the refrigeration temperature range of +32/sup 0/F to -40/sup 0/F and geothermal temperature range of 212/sup 0/F to 300/sup 0/F, an absorption refrigeration system had to be identified, designed, and evaluated. Both the conventional ammonia/water and an organic absorption refrigeration system using monochlorodifluoromethane (R-22) as the refrigerant and dimethyl formamide (DMF) as the absorbent were studied. In general, only a 60/sup 0/F to 100/sup 0/F temperature drop would be effectively used for refrigeration leaving the remainder of the allowable temperature drop available for other use. The economic evaluation of the geothermal system installed in a food processing plant required the comparison of several principal alternatives. These alternatives were evaluated for three different food processing plants located at their optimum geothermal site: a forzen potato product processing plant located at Raft River, Idaho; a freeze-dried product plant located at Sespe Hot Springs, California; a beef slaughter operation located in the Imperial Valley of California. (JGB)

  10. 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.

  11. Study of optimal discharge pressure of compressor in CO2 refrigerating trans-critical cycle

    Institute of Scientific and Technical Information of China (English)

    Fu Liehu; Wang Ruixiang; Li Qingdong; Wu Yezheng

    2008-01-01

    In this paper, a carbon dioxide trans-critical refrigerating system which is different from a conventional subcritical refrigerating cycle was studied. The trans-critical carbon dioxide refrigerating systems are based on the Gustav Lorntzen cycle. Emphasis was focused on how to determine the optimal discharge pressure of compressor in CO2 trans-critical cycle. The factors related with the optimal discharge pressure were analyzed. A formula was developed based on cycle simulation, which could be used to predict the optimal discharge pressure of a basic CO2 trans-critical cycle. After further studies on CO2 trans-critical cycles with a regenerator or expander, two more formulas were also developed. These formulas could provide an access to improve the COP of CO2 trans-critical cycle.

  12. 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)

  13. Thermodynamic Investigation of Two-Stage Absorption Refrigeration System Connected by a Compressor

    Directory of Open Access Journals (Sweden)

    L. Kairouani

    2005-01-01

    Full Text Available The present work is to analyze a two-stage cycle based on the ammonia-water absorption system, with intermediate compression. The two generators of the system are heated by geothermal energy at low temperature. The study shows that this system makes it possible at lower generator temperature, under the limits permitted by the systems suggested up to now. For Tg = 335 K, Tc = Ta = 308 K and Te = 263 K, based on the electric consumption, the system efficiency is 8.2. The comparative study of the hybrid system and vapor compression systems shows the superiority of the proposed system. Supplied by the geothermal sources of the Tunisian south, the system makes it possible to obtain for a pilot geothermal station, a production of 75 tons of ice per day. The greenhouse gas emissions should thus be reduced by about 2.38 tons of CO2 per day. Therefore, based on the typical geothermal energy sources in Tunisia which present a global refrigeration potential of 4.4 MW, the daily quantity of ice that could be produced is about 865 tons. The greenhouse gas emissions should thus be reduced by about 10,000 tons of CO2 per year.

  14. 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.

  15. Evaluation of a system of refrigeration with absorption cycle using the direct burning of natural gas for tropical fruits storage; Avaliacao de um sistema de refrigeracao com ciclo de absorcao utilizando a queima direta de gas natural para armazenamento de frutas tropicais

    Energy Technology Data Exchange (ETDEWEB)

    Bartolomeu, Lair S.; Torres, Ednildo A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Escola Politecnica. Lab. de Energia e Gas; Silva, Gabriel F. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil); Martins, Ronaldo M. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Materiais. CQDM; Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Gerencia de Tecnologia do Gas Natural. Rede GasEnergia

    2004-07-01

    This work has the purpose to analyze an alternative method in the conservation of tropical fruits in chamber cooled through the technology of use of the natural gas as energy source. The study it was carried through in chiller of absorption, Robur model, of 5TR, which meets in the campus of the Federal University of Sergipe (UFS/LEG). The energy analysis had as objective to study the process involving the cycle and its components. Of the analysis of first law was gotten a power of refrigeration of 8,8 kW and a COP=0,32 and the analysis of second law {beta}=0,29. The exergetic analysis had for intention to evaluate the amount and the quality of the energy in the system. The heat generator was the component that presented the biggest irreversibility, whose relation with the total irreversibility was about 70%. In the absorber the lesser exergetic efficiency was verified. Project is supported by the GasEnergia/PETROBRAS. (author)

  16. 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.

  17. Overview of Ionic Liquids Used as Working Fluids in Absorption Cycles

    Directory of Open Access Journals (Sweden)

    Mehrdad Khamooshi

    2013-01-01

    Full Text Available The cycle performance of refrigeration cycles depends not only on their configuration, but also on thermodynamic properties of working pairs regularly composed of refrigerant and absorbent. The commonly used working pairs in absorption cycles are aqueous solutions of either lithium bromide water or ammonia water. However, corrosion, crystallization, high working pressure, and toxicity are their major disadvantages in industrial applications. Therefore, seeking more advantageous working pairs with good thermal stability, with minimum corrosion, and without crystallization has become the research focus in the past two decades. Ionic liquids (ILs are room-temperature melting salts that can remain in the liquid state at near or below room temperature. ILs have attracted considerable attention due to their unique properties, such as negligible vapor pressure, nonflammability, thermal stability, good solubility, low melting points, and staying in the liquid state over a wide temperature range from room temperature to about 300°C. The previously mentioned highly favorable properties of ILs motivated us for carrying out the present research and reviewing the available ILs found in the literature as the working fluids of absorption cycles. Absorption cycles contain absorption heat pumps, absorption chillers, and absorption transformers.

  18. Detection Method of the Circulating Composition in a Refrigeration Cycle with Ternary Zeotropic Refrigerant Mixture R-407C

    Science.gov (United States)

    Sumida, Yoshihiro; Okazaki, Takashi; Ueno, Yoshio

    A composition sensing circuit (CS circuit) which detects the circulating composition of the ternary zeotropic refrigerant mixture R-407C in a refrigeration cycle has been developed. The CS circuit consists of a heat exchanger, a capillary tube, two temperature detectors and one pressure detector. The circulating composition is calculated from the temperature and pressure in the circuit and the vapor-liquid equilibria for R-32/R-125/R-134a mixtures together with the approximated relation between mass fractions of R-32 and R-125. The experiments were also carried out to evaluate the accuracy of calculation. The results indicated that the difference between the calculated and measured composition was within 1% f or R-32 and R-125 and within 2% for R-134a in the circulating composition range from 17/20/63 wt% to29/30/41 wt% This difference corresponds to less than 0.5°C in the saturation temperature. This method is therefore applicable to performance stabilization and reliability improvement of the refrigeration cycle with R-407C.

  19. Development of the cold end of a gravity-insensitive closed cycle dilution refrigerator

    Science.gov (United States)

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

    2012-06-01

    This work presents the experimental results and analytical modelling of the cold end of a closed-cycle gravity-insensitive dilution refrigerator adapted from the open-cycle dilution refrigerator used for the Planck mission. The refrigerator is designed to provide 1 μW of cooling at a temperature of 50 mK. The cold end of the refrigerator comprises a counterflow heat exchanger (which pre-cools the 3He and 4He components down from a temperature of about 1 K to below 100 mK), a mixing chamber and a load heat exchanger at about 50 mK. We discuss the counterflow heat exchanger designs that were considered and present experimental results. The best configuration shows a cooling power of 1 μW at 45 mK. We develop analytical models for the heat exchangers and the mixing chamber and compare them with experimental data.

  20. The control system of the ecological hybrid two stages refrigerating cycle

    Directory of Open Access Journals (Sweden)

    Cyklis Piotr

    2016-01-01

    Full Text Available The compression anticlockwise cycle is mostly used for refrigeration. However due to the environmental regulations, the use of classic refrigerants: F-gases is limited by international agreements. Therefore the combined compression-adsorption hybrid cycle with natural liquids: water/carbon dioxide working as the energy carriers is a promising solution. This allows to utilize the solar or waste energy for the refrigeration purpose. In this paper application of the solar collectors as the energy source for the adsorption cycle, coupled with the low temperature (LT refrigerating carbon dioxide compression cycle is shown. The control of the system is an essential issue to reduce the electric power consumption. The control of the solar heat supply and water sprayed cooling tower, for the adsorption cycle re-cooling, is presented in this paper. The designed control system and algorithm is related to the LT compression cycle, which operates according to the need of cold for the refrigeration chamber. The results of the laboratory investigations of the full system, showing the reduction of the energy consumption and maximum utilization of the solar heat for different control methods are presented.

  1. An open cycle absorption heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.; Longo, G.A. (Padua Univ. (Italy)); Piccininni, F. (Politecnico di Bari (Italy). Ist. di Fisica Tecnica)

    1992-09-01

    By using absorption dehumidification it is possible to obtain an open cycle absorption heat pump fed by a natural gas burner. The machine couples great simplicity with very good thermodynamic performance. The main feature is the recovery of the latent heat of the air flow. The open cycle heat pump is applied here to building heating, internal temperature 20[sup o]C, relative humidity 50%, with forced ventilation. The system has essentially a packed tower bed for dehumidification, a regenerator fed by a natural gas burner, connected to a condenser, and some heat exchangers. (author).

  2. Status of field testing of a small absorption refrigerating machine; Stand der Felderprobung einer Kleinabsorptions-Kaeltemaschine

    Energy Technology Data Exchange (ETDEWEB)

    Safarik, M.; Richter, L. [Institut fuer Luft- und Kaeltetechnik GmbH, Dresden (Germany); Weidner, G.; Otto, M. [EAW Energieanlagenbau GmbH, Westenfeld (Germany); Naumann, F.; Moeckel, F. [Hochschule fuer Technik, Wirtschaft und Kultur Leipzig (F.H.) (Germany)

    2005-07-01

    The performance efficiency and the reliability of the small absorption refrigerating machine WGRACL SE 15 are investigated by the scientific study of three plants in real operation. The systems distinguish themselves by peripheral components which allow gaining experience with the use of absorption refrigerating machines under different frame conditions. One plant could already be operated with good results during the summer 2005. Further results are expected for the cold season 2006. (orig.)

  3. The performance characteristics of an irreversible quantum Otto harmonic refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    HE JiZhou; HE Xian; TANG Wei

    2009-01-01

    In this paper,an irreversible quantum Otto refrigeration cycle working with harmonic systems is estab-lished.Base on Heisenberg quantum master equation,the equations of motion for the set of harmonic systems thermodynamic observables are derived.The simulated diagrams of the quantum Otto refrig-eration cycle are plotted.The relationship between average power of friction,cooling rate,power input,and the time of adiabatic process is analyzed by using numerical calculation.Moreover,the influence of the heat conductance and the time of iso-frequency process on the performance of the cycle is dis-cussed.

  4. The performance characteristics of an irreversible quantum Otto harmonic refrigeration cycle

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In this paper, an irreversible quantum Otto refrigeration cycle working with harmonic systems is established. Base on Heisenberg quantum master equation, the equations of motion for the set of harmonic systems thermodynamic observables are derived. The simulated diagrams of the quantum Otto refrigeration cycle are plotted. The relationship between average power of friction, cooling rate, power input, and the time of adiabatic process is analyzed by using numerical calculation. Moreover, the influence of the heat conductance and the time of iso-frequency process on the performance of the cycle is discussed.

  5. A closed cycle 3He- 4He dilution refrigerator insensitive to gravity

    Science.gov (United States)

    Martin, Florian; Vermeulen, Gerard; Camus, Philippe; Benoit, Alain

    2010-09-01

    The cooling power and the lifetime of an open cycle dilution refrigerator as developed for the Planck mission (100 nW at 100 mK during 30 months) are limited by the quantity of the helium isotopes carried on the satellite at launch, because the helium mixture obtained after the dilution process is rejected into space. Future space missions require to increase the cooling power and lifetime significantly (1 μW at 50 mK during 5 years). Therefore we are extending the open cycle dilution refrigerator with a helium isotope separator operating at 1 K to close the cycle. A first prototype to demonstrate the principle of the closed cycle dilution refrigerator has been tested and a cooling power of 1 μW at temperatures below 60 mK has been obtained. We present the apparatus and the experimental results and give some elements for its integration in a complete cooling chain. The advantages (continuous operation, absence of magnetic field, less weight) of a closed cycle dilution refrigerator with respect to an adiabatic demagnetization refrigerator are also discussed.

  6. Optimal thermoeconomic performance of an irreversible regenerative ferromagnetic Ericsson refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhichao [College of Physical Science and Technology, Xiamen University, Xiamen 361005 (China); Guo, Juncheng [College of Physics and Information Engineering, Fuzhou University, Fuzhou, 350116 China (China); Lin, Guoxing, E-mail: gxlin@xmu.edu.cn [College of Physical Science and Technology, Xiamen University, Xiamen 361005 (China); Chen, Jincan [College of Physical Science and Technology, Xiamen University, Xiamen 361005 (China)

    2016-07-01

    On the basis of the Langevin theory of classical statistical mechanics, the magnetization, entropy, and iso-field heat capacity of ferromagnetic materials are analyzed and their mathematical expressions are derived. An irreversible regenerative Ericsson refrigeration cycle by using a ferromagnetic material as the working substance is established, in which finite heat capacity rates of low and high temperature reservoirs, non-perfect regenerative heat of the refrigeration cycle, additional regenerative heat loss, etc. are taken into account. Based on the regenerative refrigeration cycle model, a thermoeconomic function is introduced as one objective function and optimized with respect to the temperatures of the working substance in the two iso-thermal processes. By means of numerical calculation, the effects of the effective factor of the heat exchangers in high/low temperature reservoir sides, efficiency of the regenerator, heat capacity rate of the low temperature reservoir, and applied magnetic field on the optimal thermoeconomic function as well as the corresponding cooling rate and coefficient of performance are revealed. The results obtained in this paper can provide some theoretical guidance for the optimal design of actual regenerative magnetic refrigerator cycle. - Highlights: • Thermodynamic performance of ferromagnetic material is analyzed. • An irreversible regenerative ferromagnetic Ericsson refrigeration cycle is set up. • The thermoeconomic objective function is introduced and optimized. • Impacts of the thermoeconomic and other parameters are discussed.

  7. Optimal analysis on the performance of an irreversible harmonic quantum Brayton refrigeration cycle.

    Science.gov (United States)

    Lin, Bihong; Chen, Jincan

    2003-11-01

    An irreversible model of a quantum refrigeration cycle working with many noninteracting harmonic oscillators is established. The refrigeration cycle consists of two adiabatic and two constant-frequency processes. The general performance characteristics of the cycle are investigated, based on the quantum master equation and the semigroup approach. The expressions for several important performance parameters such as the coefficient of performance, cooling rate, power input, and rate of entropy production are derived. By using numerical solutions, the cooling rate of the refrigeration cycle subject to finite cycle duration is optimized. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal region of the coefficient of performance and the optimal ranges of temperatures of the working substance and times spent on the two constant-frequency processes are determined. Moreover, the optimal performance of the cycle in the high-temperature limit is compared with that of a classical Brayton refrigerator working with an ideal gas. The results obtained here show that in the high-temperature limit a harmonic quantum Brayton cycle may be equivalent to a classical Brayton cycle.

  8. Advancement of Double Effect Absorption Cycle by Input of Low Temperture Waste Heat

    Science.gov (United States)

    Kojima, Hiroshi; Akisawa, Atsushi; Kashiwagi, Takao

    Energy conservation is becoming important for global environmental protection. New simple techniques of more efficiently using the waste heat of gas co-generation systems for refrigeration are required. This paper proposes a new method of using low temperature waste heat below 100°C for refrigeration. In the new method, the low temperature waste heat is fed into the weak solution line of the double effect absorption cycle directly via an auxiliary heat exchanger. In this paper, first, the location of the auxiliary waste heat recovery heat exchanger on the solution line was studied for each solution flow type of double effect absorption cycle. Then six promising methods of recovering waste heat were selected, and moreover, the basic model was constructed and the effect of input of the low temperature waste heat was investigated for each selected method.

  9. Exergoeconomic performance optimization for a steady-flow endoreversible refrigeration model including six typical cycles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lingen; Kan, Xuxian; Sun, Fengrui; Wu, Feng [College of Naval Architecture and Power, Naval University of Engineering, Wuhan 430033 (China)

    2013-07-01

    The operation of a universal steady flow endoreversible refrigeration cycle model consisting of a constant thermal-capacity heating branch, two constant thermal-capacity cooling branches and two adiabatic branches is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the refrigeration cycle is investigated by taking profit rate optimization criterion as the objective. The relations between the profit rate and the temperature ratio of working fluid, between the COP (coefficient of performance) and the temperature ratio of working fluid, as well as the optimal relation between profit rate and the COP of the cycle are derived. The focus of this paper is to search the compromised optimization between economics (profit rate) and the utilization factor (COP) for endoreversible refrigeration cycles, by searching the optimum COP at maximum profit, which is termed as the finite-time exergoeconomic performance bound. Moreover, performance analysis and optimization of the model are carried out in order to investigate the effect of cycle process on the performance of the cycles using numerical example. The results obtained herein include the performance characteristics of endoreversible Carnot, Diesel, Otto, Atkinson, Dual and Brayton refrigeration cycles.

  10. Exergoeconomic performance optimization for a steady-flow endoreversible refrigeration model including six typical cycles

    Directory of Open Access Journals (Sweden)

    Lingen Chen, Xuxian Kan, Fengrui Sun, Feng Wu

    2013-01-01

    Full Text Available The operation of a universal steady flow endoreversible refrigeration cycle model consisting of a constant thermal-capacity heating branch, two constant thermal-capacity cooling branches and two adiabatic branches is viewed as a production process with exergy as its output. The finite time exergoeconomic performance optimization of the refrigeration cycle is investigated by taking profit rate optimization criterion as the objective. The relations between the profit rate and the temperature ratio of working fluid, between the COP (coefficient of performance and the temperature ratio of working fluid, as well as the optimal relation between profit rate and the COP of the cycle are derived. The focus of this paper is to search the compromised optimization between economics (profit rate and the utilization factor (COP for endoreversible refrigeration cycles, by searching the optimum COP at maximum profit, which is termed as the finite-time exergoeconomic performance bound. Moreover, performance analysis and optimization of the model are carried out in order to investigate the effect of cycle process on the performance of the cycles using numerical example. The results obtained herein include the performance characteristics of endoreversible Carnot, Diesel, Otto, Atkinson, Dual and Brayton refrigeration cycles.

  11. Mixed refrigerant cycle with neon, hydrogen, and helium for cooling sc power transmission lines

    Science.gov (United States)

    Kloeppel, S.; Dittmar, N.; Haberstroh, Ch; Quack, H.

    2017-02-01

    The use of superconductors in very long power transmission lines requires a reliable and effective cooling. Since the use of cryocoolers does not appear feasible for very long distances, a cryogenic refrigeration cycle needs to be developed. For cooling superconducting cables based on MgB2 (T c = 39 K), liquid hydrogen (LH2) is the obvious cooling agent. For recooling LH2, one would need a refrigeration cycle providing temperatures at around 20 K. For this purpose, one could propose the use of a helium refrigeration cycle. But the very low molecular weight of helium restricts the use of turbo compressors, which limits the overall efficiency. In order to increase the molecular weight of the refrigerant a mixture of cryogens could be used, allowing the use of a turbo compressor. Temperatures below the triple point of neon are achieved by phase separation. This paper presents a possible layout of a refrigeration cycle utilizing a three component mixture of neon, hydrogen, and helium.

  12. A Preisach-Based Nonequilibrium Methodology for Simulating Performance of Hysteretic Magnetic Refrigeration Cycles

    Science.gov (United States)

    Brown, Timothy D.; Bruno, Nickolaus M.; Chen, Jing-Han; Karaman, Ibrahim; Ross, Joseph H.; Shamberger, Patrick J.

    2015-09-01

    In giant magnetocaloric effect (GMCE) materials a large entropy change couples to a magnetostructural first-order phase transition, potentially providing a basis for magnetic refrigeration cycles. However, hysteresis loss greatly reduces the availability of refrigeration work in such cycles. Here, we present a methodology combining a Preisach model for rate-independent hysteresis with a thermodynamic analysis of nonequilibrium phase transformations which, for GMCE materials exhibiting hysteresis, allows an evaluation of refrigeration work and efficiency terms for an arbitrary cycle. Using simplified but physically meaningful descriptors for the magnetic and thermal properties of a Ni45Co5Mn36.6In13.4 at.% single-crystal alloy, we relate these work/efficiency terms to fundamental material properties, demonstrating the method's use as a materials design tool. Following a simple two-parameter model for the alloy's hysteresis properties, we compute and interpret the effect of each parameter on the cyclic refrigeration work and efficiency terms. We show that hysteresis loss is a critical concern in cycles based on GMCE systems, since the resultant lost work can reduce the refrigeration work to zero; however, we also find that the lost work may be mitigated by modifying other aspects of the transition, such as the width over which the one-way transformation occurs.

  13. Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

    Science.gov (United States)

    Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

    2016-02-01

    A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

  14. Quantum refrigeration cycles using spin-1/2 systems as the working substance.

    Science.gov (United States)

    He, Jizhou; Chen, Jincan; Hua, Ben

    2002-03-01

    The cycle model of a quantum refrigerator composed of two isothermal and two isomagnetic field processes is established. The working substance in the cycle consists of many noninteracting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semigroup approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate, and power input, are given. Especially, the case at high temperatures is analyzed in detail. The results obtained are further generalized and discussed, so that they may be directly used to describe the performance of the quantum refrigerator using spin-J systems as the working substance. Finally, the optimum characteristics of the quantum Carnot refrigerator are derived simply.

  15. Simulation of an air conditioning absorption refrigeration system in a co-generation process combining a proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Pilatowsky, I.; Gamboa, S.A.; Rivera, W. [Centro de Investigacion en Energia - UNAM, Temixco, Morelos (Mexico); Romero, R.J. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas - UAEM, Cuernavaca, Morelos (Mexico); Isaza, C.A. [Universidad Pontificia Bolivariana, Medellin (Colombia). Instituto de Energia y Termodinamica; Sebastian, P.J. [Centro de Investigacion en Energia - UNAM, Temixco, Morelos (Mexico); Cuerpo Academico de Energia y Sustentabilidad-UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Moreira, J. [Cuerpo Academico de Energia y Sustentabilidad-UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-10-15

    In this work, a computer simulation program was developed to determine the optimum operating conditions of an air conditioning system during the co-generation process. A 1 kW PEMFC was considered in this study with a chemical/electrical theoretical efficiency of 40% and a thermal efficiency of 30% applying an electrical load of 100%. A refrigeration-absorption cycle (RAC) operating with monomethylamine-water solutions (MMA-WS), with low vapor generation temperatures (up to 80 C) is proposed in this work. The computer simulation was based on the refrigeration production capacity at the maximum power capacity of the PEMFC. Heat losses between the fuel cell and the absorption air conditioning system at standard operating conditions were considered to be negligible. The results showed the feasibility of using PEMFC for cooling, increasing the total efficiency of the fuel cell system. (author)

  16. Small quantum absorption refrigerator in the transient regime: Time scales, enhanced cooling, and entanglement.

    Science.gov (United States)

    Brask, Jonatan Bohr; Brunner, Nicolas

    2015-12-01

    A small quantum absorption refrigerator, consisting of three qubits, is discussed in the transient regime. We discuss time scales for coherent dynamics, damping, and approach to the steady state, and we study cooling and entanglement. We observe that cooling can be enhanced in the transient regime, in the sense that lower temperatures can be achieved compared to the steady-state regime. This is a consequence of coherent dynamics but can occur even when this dynamics is strongly damped by the dissipative thermal environment, and we note that precise control over couplings or timing is not needed to achieve enhanced cooling. We also show that the amount of entanglement present in the refrigerator can be much larger in the transient regime compared to the steady state. These results are of relevance to future implementations of quantum thermal machines.

  17. Modeling and Control of a Double-effect Absorption Refrigerating Machine

    Science.gov (United States)

    Hihara, Eiji; Yamamoto, Yuuji; Saito, Takamoto; Nagaoka, Yoshikazu; Nishiyama, Noriyuki

    Because the heat capacity of absorption refrigerating machines is large compared with vapor compression refrigerating machines, the dynamic characteristics at the change in cooling load conditions are problems to be improved. The control method of energy input and of weak solution flow rate following cooling load variations was investigated. As the changes in cooling load and cooling capacity are moderate, the optimal operation conditions corresponding to the cooling load can be estimated with steady state characteristics. If the relation between the cooling load and the optimal operation conditions is well known, a feed forward control can be employed. In this report a new control algorithm, which is called MOL (Multi-variable Open Loop) control, is proposed. Comparing the MOL control with the conventional chilled water outlet temperature proportional control, the MOL control enables the smooth changes in cooling capacity and the reduction in fuel consumption.

  18. Performance of Generator of Absorption Refrigerating Machine Powered by Hot Water

    Science.gov (United States)

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

    For 70 kW generator of absorption refrigerating machine powered by the hot water, lifted liquid rate of the bubble lift pump has a maximum value at some vapor flow rate of refrigerant and hot water inlet temperature. This is in agreement with results of small size bubble lift pump. Maximum lifted liquid rate G0 is correlated by the equation G0 = 5, 000σ1.5, where σ is the degree of submergence. In this case, diameter of pump tube was 41.6mm, and length of it were 1,300 and 1,500mm. The range of hot water inlet temperature was 78 - 100°C. Multitube heat flux of first generator is about two times that of second generator at the same superheat.

  19. First Law Analysis of a Two-stage Ejector-vapor Compression Refrigeration Cycle working with R404A

    OpenAIRE

    Feiza Memet; Daniela-Elena Mitu

    2011-01-01

    The traditional two-stage vapor compression refrigeration cycle might be replaced by a two-stage ejector-vapor compression refrigeration cycle if it is aimed the decrease of irreversibility during expansion. In this respect, the expansion valve is changed with an ejector. The performance improvement is searched in the case of choosing R404A as a refrigerant. Using the ejector as an expansion device ensures a higher value for COP compared to the traditional case. On the basis...

  20. Thermodynamics of a vapor-compression refrigeration cycle with mechanical subcooling

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, S.M. (King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Mechanical Engineering)

    1994-06-01

    A vapor-compression refrigeration cycle with a mechanical subcooling loop to increase system performance and reduce energy consumption is investigated by using both the first and second laws of thermodynamics. Although the first-law approach shows improvement in the system coefficient of performance with an increase in the temperature difference between the condenser and evaporator, it fails to locate sources of losses. A second-law analysis has been carried out for both the simple and vapor-compression refrigeration cycle with a mechanical subcooling loop. The performance significantly improved by reducing the irreversibilities due to the expansion process. (author)

  1. 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

  2. Experimental simulation of a magnetic refrigeration cycle in high magnetic fields

    Science.gov (United States)

    Dilmieva, E. T.; Kamantsev, A. P.; Koledov, V. V.; Mashirov, A. V.; Shavrov, V. G.; Cwik, J.; Tereshina, I. S.

    2016-01-01

    The complete magnetic refrigeration cycle has been simulated on a sample of gadolinium in magnetic fields of a Bitter coil magnet up to 12 T. The total change of temperature of the sample during the cycle is a consequence of magnetic refrigeration, and the dependence of the magnetization of the sample on the magnetic field exhibits a hysteretic behavior. This makes it possible to determine the work done by the magnetic field on the sample during the magnetic refrigeration cycle and to calculate the coefficient of performance of the process. In a magnetic field of 2 T near the Curie temperature of gadolinium, the coefficient of performance of the magnetic refrigeration is found to be 92. With an increase in the magnetic field, the coefficient of performance of the process decreases sharply down to 15 in a magnetic field of 12 T. The reasons, for which the coefficient of performance of the magnetic refrigeration is significantly below the fundamental limitations imposed by the reversed Carnot theorem, have been discussed.

  3. Analysis of engineering cycles power, refrigerating and gas liquefaction plant

    CERN Document Server

    Haywood, R W

    1991-01-01

    Extensively revised, updated and expanded, the fourth edition of this popular text provides a rigorous analytical treatment of modern energy conversion plant. Notable for both its theoretical and practical treatment of conventional and nuclear power plant, and its studies of refrigerating and gas-liquefaction plant. This fourth edition now includes material on topics of increasing concern in the fields of energy 'saving' and reduction of environmental pollution. This increased coverage deals specifically with the following areas: CHP (cogeneration) plant, studies of both gas and coal burning p

  4. Status of the Closed-Cycle Dilution Refrigerator Development for Space Astrophysics

    Science.gov (United States)

    Camus, Philippe; Vermeulen, Gérard; Volpe, Angela; Triqueneaux, Sébastien; Benoit, Alain; Butterworth, James; d'Escrivan, Stéphane; Tirolien, Thierry

    2014-09-01

    The closed-cycle dilution refrigerator for space applications is an on-going development to improve the performance of the open-cycle dilution refrigerator successfully used on the Planck mission. This solution has been considered in various projects in X-ray and far-infrared space instruments for astrophysics (ATHENA, SPICA) and in advanced studies for future CMB polarization surveys (COrE). It is shown that for sub-Kelvin applications, this refrigerator is fully competitive with some ADR-based solutions. Compared to ADR, the main advantages are (1) a stable cooling power adapted to long uninterrupted sky surveys (2) a low mass of the coldest stages (3) the absence of magnetic field. We present the current status of the development and discuss the options for the He compressor.

  5. Design, Fabrication and Performance Evaluation of a Micro-Absorption Refrigerator

    Directory of Open Access Journals (Sweden)

    Hyginus .U. Ugwu

    2012-11-01

    Full Text Available Developments in absorption cooling technology present an opportunity to achieve significant improvements on micro-scale to buildings, cooling, heating and power systems for residential and light commercial buildings. Their resultant effects are effective, energy efficient and economical. This study therefore contributes an important knowledge and method in the development, fabrication and application of an absorption refrigerator as a better alternative to the commonly used compressor refrigerators. In its embodiment, the work focuses on the design and fabrication of the absorption chiller system with low or no vibration since there are virtually no moving parts. Also, it dovetailed into the selection of a suitable refrigerant that is economically friendly in order to reduce or eliminate its ozone depleting effect. Consequently, the design was fabricated using adapted locally sourced materials. This is to encourage local ingenuity and to reduce cost of production comparable to already made custom-imported ones. It is designed to be simple, handy and readily available to be used by anyone in case of malfunctioning and for easy relocation. Though, the main limitation of the system fabricated is the long time it uses to achieve cooling, the performance of the machine generally is very efficient as its calculated coefficient of performance ( C.O.P is 1.21, which compared favourably well with the literature value of 1.00-2.00. Also, the total cost including an over-head of 30% of the machine was estimated at forty-one thousand, two hundred and fifty-nine (N41,259.40 naira, forty kobo only based on current price structure compared to an equivalent custom-made-imported type estimated at between sixty to seventy thousand (N60,000.00 to N70,000.00 naira. Hence, the machine is affordable to all, and is highly recommended for local entrepreneurs for mass production because of its cost effectiveness, simplicity and availability of spare parts.

  6. Optimal thermoeconomic performance of an irreversible regenerative ferromagnetic Ericsson refrigeration cycle

    Science.gov (United States)

    Xu, Zhichao; Guo, Juncheng; Lin, Guoxing; Chen, Jincan

    2016-07-01

    On the basis of the Langevin theory of classical statistical mechanics, the magnetization, entropy, and iso-field heat capacity of ferromagnetic materials are analyzed and their mathematical expressions are derived. An irreversible regenerative Ericsson refrigeration cycle by using a ferromagnetic material as the working substance is established, in which finite heat capacity rates of low and high temperature reservoirs, non-perfect regenerative heat of the refrigeration cycle, additional regenerative heat loss, etc. are taken into account. Based on the regenerative refrigeration cycle model, a thermoeconomic function is introduced as one objective function and optimized with respect to the temperatures of the working substance in the two iso-thermal processes. By means of numerical calculation, the effects of the effective factor of the heat exchangers in high/low temperature reservoir sides, efficiency of the regenerator, heat capacity rate of the low temperature reservoir, and applied magnetic field on the optimal thermoeconomic function as well as the corresponding cooling rate and coefficient of performance are revealed. The results obtained in this paper can provide some theoretical guidance for the optimal design of actual regenerative magnetic refrigerator cycle.

  7. An Automated Ac Susceptibility Set up Fabricated Using a Closed-Cycle Helium Refrigerator

    CERN Document Server

    Kundu, S

    2011-01-01

    We have described here the design and operation of an automated ac susceptibility set up using a closed cycle helium refrigerator. This set up is useful for measuring linear and nonlinear magnetic susceptibilities of various magnetic materials. The working temperature range is 2 K to 300 K. The overall sensitivity of the set up is found to be 10-3 emu.

  8. 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.

  9. Cycle simulation of the low-temperature triple-effect absorption chiller with vapor compression unit

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.S.; Lee, H.

    1999-07-01

    The construction of a triple-effect absorption chiller machine using the lithium bromide-water solution as a working fluid is strongly limited by corrosion problems caused by the high generator temperature. In this work, three new cycles having the additional vapor compression units were suggested in order to lower the generator temperature of a triple-effect absorption chiller. Each new cycle has one compressor located at the different position which was used to elevate the pressure of the refrigerant vapor. Computer simulations were carried out in order to examine both the basic triple-effect cycle and three new cycles. All types of triple-effect absorption chiller cycles were found to be able to lower the temperature of high-temperature generator to the more favorable operation range. The COPs of three cycles calculated by considering the additional compressor works showed a small level of decrease or increase compared with that of the basic triple-effect cycle. Consequently, a low-temperature triple-effect absorption chiller can be possibly constructed by adapting one of three new cycles. A great advantage of these new cycles over the basic one is that the conventionally used lithium bromide-water solution can be successfully used as a working fluid without the danger of corrosion.

  10. Thermodynamic Analysis of an Absorption/Compression Refrigeration System Using Geothermal Energy

    Directory of Open Access Journals (Sweden)

    L. Kairouani

    2005-01-01

    Full Text Available This article presents the potential use and exploration of geothermal energy for cooling applications using a combined absorption/compression system. The considered system uses R134a for the compression part and the cool water-ammonia for the absorption part of the installation. The geothermal temperature source is in the range 343-349K, the condensation temperature is 308 K, and in order to produce ice, the R134a evaporation temperature is 263 K. The COP is about 5.4. Therefore, based on the typical geothermal energy sources in Tunisia which present a refrigeration potential power of 9.1 MW, the quantity of ice that could be produced is about 82 tons per hour. The greenhouse gas emissions should thus be reduced by about 5884 tons of CO2 per year, which represents (59%.

  11. Optimization of operation of energy supply systems with co-generation and absorption refrigeration

    Directory of Open Access Journals (Sweden)

    Stojiljković Mirko M.

    2012-01-01

    Full Text Available Co-generation systems, together with absorption refrigeration and thermal storage, can result in substantial benefits from the economic, energy and environmental point of view. Optimization of operation of such systems is important as a component of the entire optimization process in pre-construction phases, but also for short-term energy production planning and system control. This paper proposes an approach for operational optimization of energy supply systems with small or medium scale co-generation, additional boilers and heat pumps, absorption and compression refrigeration, thermal energy storage and interconnection to the electric utility grid. In this case, the objective is to minimize annual costs related to the plant operation. The optimization problem is defined as mixed integer nonlinear and solved combining modern stochastic techniques: genetic algorithms and simulated annealing with linear programming using the object oriented “ESO-MS” software solution for simulation and optimization of energy supply systems, developed as a part of this research. This approach is applied to optimize a hypothetical plant that might be used to supply a real residential settlement in Niš, Serbia. Results are compared to the ones obtained after transforming the problem to mixed 0-1 linear and applying the branch and bound method.

  12. 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.

  13. The Research on Programmable Control System of Lithium-Bromide Absorption Refrigerating Air Conditioner Based on the Network

    Directory of Open Access Journals (Sweden)

    Sun Lunan

    2016-01-01

    Full Text Available This article regard the solar lithium-bromide absorption refrigerating air conditioning system as the research object, and it was conducting adequate research of the working principle of lithium bromide absorption refrigerating machine, also it was analyzing the requirements of control system about solar energy air conditioning. Then the solar energy air conditioning control system was designed based on PLC, this system was given priority to field bus control system, and the remote monitoring is complementary, which was combining the network remote monitoring technology. So that it realized the automatic control and intelligent control of new lithium bromide absorption refrigerating air conditioning system with solar energy, also, it ensured the control system can automatically detect and adjust when the external conditions was random changing, to make air conditioning work effectively and steadily, ultimately ,it has great research significance to research the air conditioning control system with solar energy.

  14. Optimal Design and Operation of Helium Refrigeration Systems Using the Ganni Cycle

    Science.gov (United States)

    Ganni, V.; Knudsen, P.

    2010-04-01

    The constant pressure ratio process, as implemented in the floating pressure—Ganni cycle, is a new variation to prior cryogenic refrigeration and liquefaction cycle designs that allows for optimal operation and design of helium refrigeration systems. This cycle is based upon the traditional equipment used for helium refrigeration system designs, i.e., constant volume displacement compression and critical flow expansion devices. It takes advantage of the fact that for a given load, the expander sets the compressor discharge pressure and the compressor sets its own suction pressure. This cycle not only provides an essentially constant system Carnot efficiency over a wide load range, but invalidates the traditional philosophy that the (`TS') design condition is the optimal operating condition for a given load using the as-built hardware. As such, the Floating Pressure-Ganni Cycle is a solution to reduce the energy consumption while increasing the reliability, flexibility and stability of these systems over a wide operating range and different operating modes and is applicable to most of the existing plants. This paper explains the basic theory behind this cycle operation and contrasts it to the traditional operational philosophies presently used.

  15. OPTIMAL DESIGN AND OPERATION OF HELIUM REFRIGERATION SYSTEMS USING THE GANNI CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Venkatarao Ganni, Peter Knudsen

    2010-04-01

    The constant pressure ratio process, as implemented in the floating pressure - Ganni cycle, is a new variation to prior cryogenic refrigeration and liquefaction cycle designs that allows for optimal operation and design of helium refrigeration systems. This cycle is based upon the traditional equipment used for helium refrigeration system designs, i.e., constant volume displacement compression and critical flow expansion devices. It takes advantage of the fact that for a given load, the expander sets the compressor discharge pressure and the compressor sets its own suction pressure. This cycle not only provides an essentially constant system Carnot efficiency over a wide load range, but invalidates the traditional philosophy that the (‘TS’) design condition is the optimal operating condition for a given load using the as-built hardware. As such, the Floating Pressure- Ganni Cycle is a solution to reduce the energy consumption while increasing the reliability, flexibility and stability of these systems over a wide operating range and different operating modes and is applicable to most of the existing plants. This paper explains the basic theory behind this cycle operation and contrasts it to the traditional operational philosophies presently used.

  16. 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.

  17. Thermodynamic Analysis of Double-Stage Compression Transcritical CO2 Refrigeration Cycles with an Expander

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2015-04-01

    Full Text Available Four different double-compression CO2 transcritical refrigeration cycles are studied: double-compression external intercooler cycle (DCEI, double-compression external intercooler cycle with an expander (DCEIE, double-compression flash intercooler cycle (DCFI, double-compression flash intercooler cycle with an expander (DCFIE. The results showed that the optimum gas cooler pressure and optimum intermediate pressure of the flash intercooler cycles are lower than that of the external intercooler cycle. The use of an expander in the DCEI cycle leads to a decrease of the optimum gas cooler pressure and little variation of the optimum intermediate pressure. However, the replacement of the throttle valve with an expander in the DCFI cycle results in little variation of the optimal gas cooler pressure and an increase of the optimum intermediate pressure. The DCFI cycle outperforms the DCEI cycle under all the chosen operating conditions. The DCEIE cycle outperforms the DCFIE cycle when the evaporating temperature exceeds 0 °C or the gas cooler outlet temperature surpasses 35 °C. When the gas cooler exit temperature varies from 32 °C to 48 °C, the DCEI cycle, DCEIE cycle, DCFI cycle and DCFIE cycle yield averaged 4.6%, 29.2%, 12.9% and 22.3% COP improvement, respectively, over the basic cycle.

  18. Impact of cycle-hysteresis interactions on the performance of giant magnetocaloric effect refrigerants

    Science.gov (United States)

    Brown, T. D.; Karaman, I.; Shamberger, P. J.

    2016-07-01

    Magnetic refrigeration technology based on the giant magnetocaloric effect in solid-state refrigerants is known qualitatively to be limited by dissipative mechanisms accompanying hysteresis in the magneto-structural solid-solid phase transition. In this paper, we quantitatively explore the dependence of cycle performance metrics (cooling power, temperature span, work input, and fractional Carnot efficiency) on hysteresis properties (thermal hysteresis, one-way transition width) of the magneto-structural phase transition in a Ni45Co5Mn36.6In13.4 alloy system. We investigate a variety of Ericsson-type magnetic refrigeration cycles, using a Preisach-based non-equilibrium thermodynamic framework to model the evolution of the alloy's magnetic and thermal properties. Performance metrics are found to depend strongly on hysteresis parameters, regardless of the cycle chosen. However, for a given hysteresis parameter set, the material's transformation temperatures determine a unique cycle that maximizes efficiency. For the model system used undergoing Ericsson cycles with 5 and 1.5 {{T}} maximum field constraint, fractional Carnot efficiencies in excess of 0.9 require thermal hysteresis below 1.5 {{K}} and 0.5 {{K}}, respectively. We conclude briefly with some general materials considerations for mitigating these hysteresis inefficiencies through microstructure design and other materials processing strategies.

  19. Static Analysis of Double Effect Adsorption Refrigeration Cycle Using Silica gel/Water Pair

    Science.gov (United States)

    Marlinda; Miyazaki, Takahiko; Ueda, Yuki; Akisawa, Atsushi

    In this paper,a static analysis of double effect adsorption refrigeration cycle utilizing condensation heat is discussed. Double effect adsorption refrigeration cycle consists of two cycles, High Temperature Cycle (HTC) which is driven from external heat sources, and Low Temperature Cycle (LTC) which is driven by condensation heat from HTC. Both of HTC and LTC are using silica gel and water as working pairs. The effect of heat source temperature on cycle performance was investigated in terms of coefficient of performance (COP) and specific cooling energy (SCE). Results showed that double effect cycle would produce higher COP than single effect cycle for driving temperature observed between 80-150°C with the same operating condition. However, the value of SCE is lower than single effect, despite that the SCE of double effect cycle is improved with heat source temperature higher than 100°C. Further, it was also observed that adsorbent mass ratio of HTC and LTC affected performance of chiller. When adsorbent mass ratio of HTC and LTC was unity, it was found that SCE and COP took the maximum.

  20. Performance evaluation of combined ejector LiBr/H2O absorption cooling cycle

    Directory of Open Access Journals (Sweden)

    Hasan Sh. Majdi

    2016-03-01

    Full Text Available The objective of this work is to develop a computer simulation program to evaluate the performance of solar-assited combined ejector absorption (single-effect cooling system using LiBr/H2O as a working fluid and operating under steady-state conditions. The ejector possess no moving parts and is simple and reliable, which makes it attractive for combination with single-stage absorption cycle for further improvement to the system's performance. In this research, improvement to the system is achieved by utilizing the potential kinetic energy of the ejector to enhance refrigeration efficiency. The effects of the entrainment ratio of the ejector, operating temperature, on the thermal loads, and system performance have been investigated. The results showed that the evaporator and condenser loads, post-addition of the ejector, is found to be permanently higher than that in the basic cycle, which indicates a significant enhancement of the proposed cycle and the cooling capacity of the system increasing with the increase in evaporator temperature and entrainment ratio. The COP of the modified cycle is improved by up to 60 % compared with that of the basic cycle at the given condition. This process stabilizes the refrigeration system, enhanced its function, and enabled the system to work under higher condenser temperatures.

  1. Numerical Study on the Design of Microchannel Evaporators for Ejector Refrigeration Cycles

    OpenAIRE

    Lawrence, Neal; Elbel, Stefan

    2016-01-01

    Two-phase ejectors are devices capable of improving the performance of refrigeration and air conditioning cycles by means of expansion work recovery. Ejector studies often focus on the design and performance of the two-phase ejector and the effect it can have on the performance of the ejector cycle. However, the ejector is not the only component of the system that can have a significant influence on the performance of the ejector cycle. Recent experimental work has shown that the effect of ev...

  2. Performance of V-type Stirling-cycle refrigerator for different working fluids

    Energy Technology Data Exchange (ETDEWEB)

    Tekin, Yusuf; Ataer, Omer Ercan [Erciyes University, Engineering Faculty, Mechanical Engineering Department, Melikgazi, 38 039 Kayseri (Turkey)

    2010-01-15

    The thermodynamic analysis of a V-type Stirling-cycle Refrigerator (VSR) is performed for air, hydrogen and helium as the working fluid and the performance of the VSR is investigated. The V-type Stirling-cycle refrigerator consists of expansion and compression spaces, cooler, heater and regenerator, and it is assumed that the control volumes are subjected to a periodic mass flow. The basic equations of the VSR are derived for per unit crank angle, so time does not appear in the equations. A computer program is prepared in FORTRAN, and the basic equations are solved iteratively. The mass, temperature and density of working fluid in each control volume are calculated for different charge pressures, engine speeds, and for fixed heater and cooler surface temperatures. The work, instantaneous pressure and the COP of the VSR are calculated. The results are obtained for different working fluids, and given by diagrams. (author)

  3. Mechanism of refrigeration cycle on laser cooling of solids

    Institute of Scientific and Technical Information of China (English)

    Youhua Jia; Biao Zhong; Jianping Yin

    2012-01-01

    A simple model is developed to study the laser cooling of solids. The condition of laser cooling of a solid is developed. By using some parameters of the Yb3+ ion, which is most widely used in laser cooling, we then calculate the cooling power and the cooling efficiency. In order to make a more precise analysis, the effect of fluorescent reabsorption, which is unavoidable in the cooling process, is discussed using the random walk model. Taking Tm3+ ion as an example, we derive the average number of absorption events and determine the change in quantum efficiency due to reabsorption. Finally, we obtain the red-shift of the fluorescent wavelength and the requirement of sample dimension.%A simple model is developed to study the laser cooling of solids.The condition of laser cooling of a solid is developed.By using some parameters of the Yb3+ ion,which is most widely used in laser cooling,we then calculate the cooling power and the cooling efficiency.In order to make a more precise analysis,the effect of fluorescent reabsorption,which is unavoidable in the cooling process,is discussed using the random walk model.Taking Tm3+ ion as an example,we derive the average number of absorption events and determine the change in quantum efficiency due to reabsorption.Finally,we obtain the red-shift of the fluorescent wavelength and the requirement of sample dimension.

  4. Effects of leakage through clearance seals on the performance of a 10 K Stirling-cycle refrigerator

    Science.gov (United States)

    Keung, C. S.; Lindale, E.

    1985-01-01

    The use of clearance seals is essential to achieve long life, wear free operation of Stirling cycle cryogenic refrigerators. The effect of leakage through clearance seals on the performance of such a refrigerator operating at temperatures ranging from 20 K down to 10 K was determined. The ability of a Stirling cycle refrigerator to achieve 10 K with clearance seals was successfully demonstrated. It is indicated that the leakage flow undergoes gap regeneration before reaching the cold expansion volume. A simple model of gap regeneration was used to estimate the regeneration loss due to the leakage flow. This regeneration process minimizes the loss in refrigerator performance caused by the clearance seal leakage. It is found that clearance seals remain effective down to a refrigeration temperature of 10 K.

  5. 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.

  6. Cogen-absorption plants for refrigeration purposes and turbine air inlet cooling

    Energy Technology Data Exchange (ETDEWEB)

    Langreck, Juergen [Colibri bv (Netherlands)

    2000-04-01

    Most cogeneration systems produce power and heat but with absorption refrigeration plants (ARP) the products are power and 'cold'. An ARP driven by heat from a turbine exhaust can provide the cooling for the inlet air with very low consumption of electricity, consequently there is a significant increase in power output from the cogeneration unit. Two different ARP systems are currently available but the author describes only the ammonia-water system, which can achieve temperatures down to -60 degrees C. The article discusses the principle behind ARP, the capital cost and returns on investment, how the cogeneration plant is linked to the ARP, ARP for turbine inlet air cooling, and the potential applications of cogeneration-ARP.

  7. Helium compressors for closed-cycle, 4.5-Kelvin refrigerators

    Science.gov (United States)

    Hanson, T. R.

    1992-01-01

    An improved helium compressor for traveling-wave maser and closed-cycle refrigerator systems was developed and is currently being supplied to the DSN. This new 5-hp compressor package is designed to replace the current 3-hp DSN compressors. The new compressor package was designed to retrofit into the existing 3-hp compressor frame and reuse many of the same components, therefore saving the cost of documenting and fabricating these components when implementing a new 5-hp compressor.

  8. COP Prediction of an ejector refrigeration cycle combined with a vapour compression cycle for automotive air conditioning

    Directory of Open Access Journals (Sweden)

    Nat Suvarnakuta

    2014-03-01

    Full Text Available This paper presents the COP prediction of an ejector refrigeration cycle combined with a vapour compression cycle for automotive air conditioning. Using computational fluid dynamics (CFD technique, the performance of an ejector was analyzed in term of the entrainment ratio (Rm and critical back pressure (CBP. The results from this study were compared with a previous study of combined ejector refrigeration system for automotive air conditioning application [1] which the entrainment ratio (Rm were predicted from one-dimensional (1-D equation. The performance of an ejector (Rm and CBP from CFD and onedimensional method were analyzed and used as database for a mathematical modeling. In order to predict the COP of the combined system, a set of mathematical equations was developed using EES. The operating conditions are chosen accordingly as, intercooler temperature between 15 ๐ C and 25 ๐ C, condenser temperature equal to 35 ๐ C and evaporator temperature equal to 5 ๐ C. However, when generator temperatures are 80 ๐ C, 85 ๐ C and 90 ๐ C, the results showed average relative errors of the COP of an ejector refrigeration cycle (COPej, between CFD and 1-D are 44.64%, 50.47% and 59.68% respectively, and between CFD and 1-D NEW are 1.54%, 0.08% and 6.49% respectively.

  9. First Law Analysis of a Two-stage Ejector-vapor Compression Refrigeration Cycle working with R404A

    Directory of Open Access Journals (Sweden)

    Feiza Memet

    2011-10-01

    Full Text Available The traditional two-stage vapor compression refrigeration cycle might be replaced by a two-stage ejector-vapor compression refrigeration cycle if it is aimed the decrease of irreversibility during expansion. In this respect, the expansion valve is changed with an ejector. The performance improvement is searched in the case of choosing R404A as a refrigerant. Using the ejector as an expansion device ensures a higher value for COP compared to the traditional case. On the basis of the ejector approach it possible to identify the highest COP value for a given condensation temperature, when the evaporation temperature varies.

  10. Industrial refrigeration with high efficiency absorption; Refrigeracion industrial por absorcion de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Ayala Delgado, R.; Heard, C. L. [Instituto de Investigaciones Electricas, Cuernavaca, (Mexico); Pardubicki, J. [LAJ International, Mexico D. F. (Mexico)

    1995-12-31

    The absorption refrigeration ammonia-lithium nitrate offers great advantages compared with the mechanical compression refrigeration with ammonia as well as with the absorption ammonia-water refrigeration. With heat temperatures of 1000 to 1400 Celsius degrees, for instance low pressure steam the generation of cold at low temperatures (-100 to -200 Celsius degrees) is possible. The system has less components and is much less expensive than the ammonia-water equipment with a price very similar to the ammonia mechanical compression equipment. The equipment consists of five main heat exchangers and a solution pump, resulting in a high reliability of its operation, requiring a minimum maintenance. The operation cost depends directly of the cost of the energy source. In case of using residual heat the operation cost is only the maintenance cost. Nowadays the cost of the electric energy is below the production cost, which can be a short term situation. In time terms of the comparable useful life time of an absorption refrigeration system (in excess of 20 years), it is reasonable to think that the operation costs will be less than the operation costs of an equipment with mechanical compression. To this day it is available a demonstration unit to exhibit the system in industrial plants with different energy sources. [Espanol] La refrigeracion por absorcion amoniaco/nitrato de litio ofrece grandes ventajas comparada tanto con la refrigeracion por compresion mecanica con amoniaco como con la refrigeracion por absorcion amoniaco/agua. Este sistema es mas eficiente y sencillo que el sistema de amoniaco/agua. Con calor de temperatura (100 a 140 grados centigrados por ejemplo vapor de baja presion, se permite la generacion de frio a temperaturas bajas (-10 a -20 grados centigrados). El sistema tiene menos componentes y es mucho mas barato que equipo de amoniaco/agua con un precio muy similar a sistemas por compresion mecanica de amoniaco. El sistema consiste en cinco

  11. Parametric optimum analysis of an irreversible Ericsson cryogenic refrigeration cycle working with an ideal Fermi gas

    Indian Academy of Sciences (India)

    Bihong Lin; Yingru Zhao; Jincan Chen

    2008-05-01

    An irreversible model of an Ericsson cryogenic refrigeration cycle working with an ideal Fermi gas is established, which is composed of two isothermal and two isobaric processes. The influence of both the quantum degeneracy and the finite-rate heat transfer between the working fluid and the heat reservoirs on the performance of the cycle is investigated, based on the theory of statistical mechanics and thermodynamic properties of an ideal Fermi gas. The inherent regeneration losses of the cycle are analyzed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. Especially, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit is discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Ericsson refrigeration cycles working with the Fermi and classical gases are revealed.

  12. Profit rate performance optimization for a generalized irreversible combined refrigeration cycle

    Indian Academy of Sciences (India)

    Kang Ma; Lingen Chen; Fengrui Sun

    2009-10-01

    Finite-time exergoeconomic performance of a Newtonian heat transfer law system generalized irreversible combined refrigeration cycle model with finite-rate heat transfer, heat leakage and internal irreversibility is presented in this paper. The operation of the generalized irreversible combined refrigeration cycle is viewed as a production process with exergy as its output. The performance optimization of the cycle is performed by taking profit as the objective. The optimal profit rate, optimal COP (coefficient of performance), as well as the relation between the optimal profit rate and COP of the cycle are derived. The focus of this paper is to obtain the compromise optimization between economics (profit rate) and the energy utilization factor (COP) for the cycle, by searching the optimum COP at maximum profit rate, which is termed as the finite time exergoeconomic performance bound. Moreover, the effects of various factors, including heat leakage, internal irreversibility and the price ratio, on the profit rate performance of the cycle are analysed by detailed numerical examples.

  13. 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....

  14. The optimal performance of a quantum refrigeration cycle working with harmonic oscillators

    CERN Document Server

    Lin Bi Hong; Hua Ben

    2003-01-01

    The cycle model of a quantum refrigeration cycle working with many non-interacting harmonic oscillators and consisting of two isothermal and two constant-frequency processes is established. Based on the quantum master equation and semi-group approach, the general performance of the cycle is investigated. Expressions for some important performance parameters, such as the coefficient of performance, cooling rate, power input, and rate of the entropy production, are derived. Several interesting cases are discussed and, especially, the optimal performance of the cycle at high temperatures is discussed in detail. Some important characteristic curves of the cycle, such as the cooling rate versus coefficient of performance curves, the power input versus coefficient of performance curves, the cooling rate versus power input curves, and so on, are presented. The maximum cooling rate and the corresponding coefficient of performance are calculated. Other optimal performances are also analysed. The results obtained here ...

  15. A closed-cycle refrigerator for cooling maser amplifiers below 4 Kelvin

    Science.gov (United States)

    Britcliffe, M.

    1989-01-01

    A helium refrigerator utilizing the Gifford-McMahon/Joule-Thomson (GM/JT) cycle was designed and tested to demonstrate the feasibility of using small closed-cycle refrigerators as an alternative to batch-filled cryostats for operating temperatures below 4 K. The systems could be used to cool low-noise microwave maser amplifiers located in large parabolic antennas. These antennas tilt vertically, making conventional liquid-filled dewars difficult to use. The system could also be used for a non-tilting beam waveguide antenna to reduce the helium consumption of a liquid helium cryostat. The prototype system is adjustable to provide 700 mW of cooling at 2.5 K to 3 W at 4.3 K. Performance of the unit is not significantly affected by physical orientation. The volume occupied by the refrigerator is less than 0.1 cu m. Two JT expansion stages are used to maximize cooling capacity per unit mass flow. The heat exchangers were designed to produce minimum pressure drop in the return gas stream. Pressure drop for the entire JT return circuit is less than 5 kpa at a mass flow of 0.06 g/sec when operating at 2.5 K.

  16. Development of vapor compression refrigeration cycle with a natural-circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, Takashi; Sumida, Yoshihiro; Matsushita, Akihiro

    1999-07-01

    Vapor compression refrigeration cycle with a natural-circulation loop (VCNC) has been developed to save energy for an air conditioner of shelters of electronic facilities. VCNC consists of a compressor, a condenser, a liquid pipe, an evaporator, a gas pipe, an accumulator and three valves. VCNC has two operating modes; vapor compression mode and natural-circulation mode, which are easily changed by the values. The experiments were carried out to evaluate the cycle performance in natural-circulation mode, and calculations were performed to examine the energy consumption of VCNC using the profile of seasonal environmental temperature in Tokyo. The experimental results indicated that the cooling capacity in natural-circulation mode depended on the amount of charged refrigerant and took a maximum value in the case that the refrigerant at the outlet of the evaporator became saturated vapor. Also, the cooling capacity in natural-circulation mode linearly increased as the outdoor temperature decreased. The calculated results indicated that the operating ratio of the compressor of VCNC was approximately 70% smaller than that of conventional air conditioners (VC). Furthermore, the energy consumption of VCNC was approximately 50% lower than that of VC.

  17. Performance analysis of irreversible quantum Stirling cryogenic refrigeration cycles and their parametric optimum criteria

    Science.gov (United States)

    Lin, Bihong; Chen, Jincan

    2006-08-01

    The influence of both the quantum degeneracy and the finite-rate heat transfer between the working substance and the heat reservoirs on the optimal performance of an irreversible Stirling cryogenic refrigeration cycle using an ideal Fermi or Bose gas as the working substance is investigated, based on the theory of statistical mechanics and thermodynamic properties of ideal quantum gases. The inherent regeneration losses of the cycle are analysed. Expressions for several important performance parameters such as the coefficient of performance, cooling rate and power input are derived. By using numerical solutions, the cooling rate of the cycle is optimized for a given power input. The maximum cooling rate and the corresponding parameters are calculated numerically. The optimal regions of the coefficient of performance and power input are determined. In particular, the optimal performance of the cycle in the strong and weak gas degeneracy cases and the high temperature limit are discussed in detail. The analytic expressions of some optimized parameters are derived. Some optimum criteria are given. The distinctions and connections between the Stirling refrigeration cycles working with the ideal quantum and classical gases are revealed.

  18. Performance Analysis of Solar Combined Ejector-Vapor Compression Cycle Using Environmental Friendly Refrigerants

    Directory of Open Access Journals (Sweden)

    A. B. Kasaeian

    2013-04-01

    Full Text Available In this study, a new model of a solar combined ejector-vapor compression refrigeration system has been considered. The system is equipped with an internal heat exchanger to enhance the performance of the cycle. The effects of working fluid and operating conditions on the system performance including COP, entrainment ratio (ω, compression ratio (rp and exergy efficiency were investigated. Some working fluids suggested are: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e and R1234ze(z. The results show that R114 and R1234ze(e yield the highest COP and exergy efficiency followed by R123, R245fa, R365mfc, R141b, R152a and R600a. It is noticed that the COP value of the new solar ejector-vapor compression refrigeration cycle is higher than that of the conventional ejector cycle with R1234ze(e for all operating conditions. This paper also demonstrates that R1234ze(e will be a suitable refrigerant in the solar combined ejector-vapor compression refrigeration system, due to its environmental friendly properties and better performance. ABSTRAK: Kajian ini menganalisa model baru sistem penyejukan mampatan gabungan ejektor-wap solar.Sistem ini dilengkapi dengan penukar haba dalaman untuk meningkatkan prestasi kitaran.Kesan bendalir bekerja dan keadaan operasi pada prestasi sistem termasuk COP, nisbah pemerangkapan (ω, nisbah mampatan (rp dan kecekapan eksergi telah disiasat.Beberapa bendalir bekerja yang dicadangkan adalah: R114, R141b, R123, R245fa, R600a, R365mfc, R1234ze(e dan R1234ze(z.Hasil kajian menunjukkan R114 dan R1234ze(e menghasilkan COP dan kecekapan eksergi tertinggi diikuti oleh R123, R245fa, R365mfc, R141b, R152a dan R600a.Didapati nilai COP kitaran penyejukan mampatan bagi ejektor-wap solar baru adalah lebih tinggi daripada kitaran ejektor konvensional dengan R1234ze(e bagi semua keadaan operasi.Kertas kerja ini juga menunjukkan bahawa R1234ze(e boleh menjadi penyejuk yang sesuai dalam sistem penyejukan mampatan gabungan ejektor

  19. An analysis of the performance of an ejector refrigeration cycle working with R134a

    Science.gov (United States)

    Memet, F.; Preda, A.

    2015-11-01

    In the context of recent developments in the field of energy, the aspect related to energy consumption is of great importance for specialists. Many industries rely on refrigeration technologies, a great challenge being expressed by attempts in energy savings in this sector. In this respect, efforts oriented towards efficient industrial refrigeration systems have revealed the necessity of a proper design. The most commonly used method of cooling is based on vapor compression cycles. Compared to vapor compression refrigeration systems, an ejector refrigeration system shows an inferior performance, indicated by the Coefficient of Performance of the cycle, but it is more attractive from energy saving point of view. In this respect, the present study deals with a theoretically analysis of an Ejector Refrigeration System, started with the presentation of the typical ejector design. It is stated that ejector refrigeration is a thermally driven system which requires low grade thermal energy for its working. After a short description of the analyzed system, are given equations for thermal loads and Coefficient of Performance calculation, on First Law basis. The working fluid considered in this research is Freon R134a. The developed study is focused on the effect of generating temperature variation on the Coefficient of Performance (COP) and on the work input to the pump when the cooling effect, the condensation temperature, the evaporation temperature and the reference state temperature are kept constant. Are obtained results in the following conditions: the condensation temperature is tc = 33°C, the evaporation temperature is te = 3°C, the reference state temperature is to = 23°C. The generating temperature varies in the range 82 ÷ 92°C and the cooling effect is 1 kW. Also, are known the isentropic efficiencies of the ejector, which are 0.90, and the isentropic efficiency of the pump, which is 0.75. Calculation will reveal that the Coefficient of Performance is

  20. 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)

  1. A Review on Diffusion Absorption Refrigeration Technology%扩散吸收式制冷技术进展

    Institute of Scientific and Technical Information of China (English)

    曹园树; 李华山; 龙臻; 卜宪标; 马伟斌

    2014-01-01

    The diffusion absorption refrigeration (DAR) that could use low-grade thermal sources such as solar energy and waste heat, etc, is an environmental-friendly and energy-efficient technology and thus has a very promising prospect. By reviewing the latest researches around the world, this paper introduces the main findings for the DAR technology from three aspects including working fluid selection, cycle thermodynamic analysis as well as system improvement and optimization. Also, the development trends and future research directions of the DAR technology are presented. Some research works done by our team are also summarized.%扩散吸收式制冷(Diffusion Absorption Refrigeration,DAR)能够利用低品位能源如太阳能和余热等,是一种有利于环保和能源高效利用的技术,具有十分广阔的应用前景。结合国内外的最新研究动态,本文从工质选择、循环热力学分析、系统改进与优化研究三个方面介绍扩散吸收式制冷技术的主要研究成果,并对扩散吸收式制冷技术的发展趋势以及未来研究方向进行展望。同时,对本课题组关于扩散吸收式制冷所做的工作也进行了总结。

  2. Experimental Study of the Effects of the Cycle Characteristics on the Refrigerant-Induced Noise in System Air-Conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Weui Bong [Pusan National University, Busan (Korea, Republic of); Han, Hyung Suk; Mo, Jin Yong; Lee, Jae Kwon [Samsung Electronics, Suwon (Korea, Republic of)

    2007-07-15

    The main sources of the refrigerant-induced noise can be classified 2 types according to its characteristics. One is due to the cyclic characteristics such as quality, velocity of the refrigerant, pressure drop and mass flow rate. The other is due to the structural characteristics such as distributed path pipe layout, distributor and expansion device. In this paper, the effects of cycle characteristics on the noise of multi-type system air-conditioner are investigated experimentally. In the indoor unit of multi-type air-conditioner, the variation of noise is examined when the in-flowing and out-flowing refrigerant to the indoor unit are 2-phase state according to its cycle control. And several factors are recommended in order to reduce the refrigerant-induced noise of the air-conditioner.

  3. Exergy Analysis of a Subcritical Refrigeration Cycle with an Improved Impulse Turbo Expander

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2014-08-01

    Full Text Available The impulse turbo expander (ITE is employed to replace the throttling valve in the vapor compression refrigeration cycle to improve the system performance. An improved ITE and the corresponding cycle are presented. In the new cycle, the ITE not only acts as an expansion device with work extraction, but also serves as an economizer with vapor injection. An increase of 20% in the isentropic efficiency can be attained for the improved ITE compared with the conventional ITE owing to the reduction of the friction losses of the rotor. The performance of the novel cycle is investigated based on energy and exergy analysis. A correlation of the optimum intermediate pressure in terms of ITE efficiency is developed. The improved ITE cycle increases the exergy efficiency by 1.4%–6.1% over the conventional ITE cycle, 4.6%–8.3% over the economizer cycle and 7.2%–21.6% over the base cycle. Furthermore, the improved ITE cycle is also preferred due to its lower exergy loss.

  4. Proceedings of the 1993 non-fluorocarbon insulation, refrigeration and air conditioning technology workshop

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    Sessions included: HFC blown polyurethanes, carbon dioxide blown foam and extruded polystyrenes, plastic foam insulations, evacuated panel insulation, refrigeration and air conditioning, absorption and adsorption and stirling cycle refrigeration, innovative cooling technologies, and natural refrigerants. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  5. Flow field analysis of high-speed helium turboexpander for cryogenic refrigeration and liquefaction cycles

    Science.gov (United States)

    Sam, Ashish Alex; Ghosh, Parthasarathi

    2017-03-01

    Turboexpander constitutes one of the vital components of Claude cycle based helium refrigerators and liquefiers that are gaining increasing technological importance. These turboexpanders which are of radial inflow in configuration are generally high-speed micro turbines, due to the low molecular weight and density of helium. Any improvement in efficiency of these machines requires a detailed understanding of the flow field. Computational Fluid Dynamics analysis (CFD) has emerged as a necessary tool for the determination of the flow fields in cryogenic turboexpanders, which is often not possible through experiments. In the present work three-dimensional transient flow analysis of a cryogenic turboexpander for helium refrigeration and liquefaction cycles were performed using Ansys CFX®, to understand the flow field of a high-speed helium turboexpander, which in turn will help in taking appropriate decisions regarding modifications of established design methodology for improved efficiency of these machines. The turboexpander is designed based on Balje's nsds diagram and the inverse design blade profile generation formalism prescribed by Hasselgruber and Balje. The analyses include the study of several losses, their origins, the increase in entropy due to these losses, quantification of losses and the effects of various geometrical parameters on these losses. Through the flow field analysis it was observed that in the nozzle, flow separation at the nozzle blade suction side and trailing edge vortices resulted in loss generation, which calls for better nozzle blade profile. The turbine wheel flow field analysis revealed that the significant geometrical parameters of the turbine wheel blade like blade inlet angle, blade profile, tip clearance height and trailing edge thickness need to be optimised for improved performance of the turboexpander. The detailed flow field analysis in this paper can be used to improve the mean line design methodology for turboexpanders used

  6. 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.

  7. Thermodynamic study of air-cycle and mercury-vapor-cycle systems for refrigerating cooling air for turbines or other components

    Science.gov (United States)

    Nachtigall, Alfred J; Freche, John C; Esgar, Jack B

    1956-01-01

    An analysis of air refrigeration systems indicated that air cycles are generally less satisfactory than simple heat exchangers unless high component efficiencies and high values of heat-exchanger effectiveness can be obtained. A system employing a mercury-vapor cycle appears to be feasible for refrigerating air that must enter the system at temperature levels of approximately 1500 degrees R, and this cycle is more efficient than the air cycle. Weight of the systems was not considered. The analysis of the systems is presented in a generalized dimensionless form.

  8. Traveling-wave maser closed-cycle refrigerator data acquisition and display system

    Science.gov (United States)

    Fowler, L.; Britcliffe, M.

    1987-01-01

    A data acquisition and display system that automatically monitors the performance of the 4.5-K closed-cycle refrigerators used to cryogenically cool traveling-wave masers is described. The system displays and stores operating parameters for the purpose of providing status information, failure prediction, and analysis. A prototype of this system will be installed at Deep Space Network 12 in the near future. The advantages of using commercial data acquisition hardware with installed operating systems and BASIC programs for this application are discussed.

  9. Traveling-wave maser closed-cycle refrigerator data acquisition and display system

    Science.gov (United States)

    Fowler, L.; Britcliffe, M.

    1987-11-01

    A data acquisition and display system that automatically monitors the performance of the 4.5-K closed-cycle refrigerators used to cryogenically cool traveling-wave masers is described. The system displays and stores operating parameters for the purpose of providing status information, failure prediction, and analysis. A prototype of this system will be installed at Deep Space Network 12 in the near future. The advantages of using commercial data acquisition hardware with installed operating systems and BASIC programs for this application are discussed.

  10. Application of Absorption Refrigeration in the Coal Mine & Fluent Simulation%吸收式制冷在深部矿井高温热害处理中的应用与FLUENT模拟计算

    Institute of Scientific and Technical Information of China (English)

    杨前明; 杜雪

    2015-01-01

    For mine deep heat damage problem, effective use of low-grade waste heat of the Swallet, as the driving heat absorption refrigeration constructed absorption refrigeration, resolve deep coal thermal damage circulatory system through the use of deep water source heat pump heated gushing, so lithium bromide absorption chiller cooling at the same time on the working surface, as the heat absorption refrigeration cycle using design using auxiliary heating source heat pump to drive the refrigeration unit Swallet system. Fluent use of numerical simulation of the text, comparative analysis of the effect of coal mine deep under the best air cooling conditions, to provide a theoretical basis for the absorption refrigeration technology in actual use in deep.%针对煤矿深部热害问题,提出了利用矿井涌水中的低品位废热,作为吸收式制冷的驱动热源,构建了吸收式制冷循环系统解决煤矿深部开采工作面热害问题。依据煤矿深井开采工作面热舒适度要求,对制冷降温系统热参数进行估算;运用Fluent数值模拟,对比分析出最佳送风条件下的煤矿深井制冷效果。理论分析与数值模拟结果表明了采用吸收式制冷循环解决煤矿深井开采工作面热害问题可行性。

  11. Mass transfer characteristics of a structured packing for ammonia rectification in ammonia-water absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Sieres, Jaime; Fernandez-Seara, Jose [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende N9, 36310 Vigo (Spain)

    2007-01-15

    In ammonia-water absorption refrigeration systems a purification process of the vapours produced in the generator is required. One type of equipment to carry out the purification process is a packed column. However, detailed experimental studies at the normal operating conditions found in ammonia-water absorption refrigeration systems have not been found. An experimental facility has been designed and built to study the ammonia-water rectification in packed columns. Experimental tests have been performed at the normal operating conditions found in the high-pressure stage of a small power ammonia-water absorption refrigeration system. In this paper, the experimental set-up is described and experimental results of the height equivalent to a theoretical plate (HETP) and the volumetric mass transfer coefficient of a rectifying section with the Sulzer BX packing are presented. The HETP values and the experimental mass transfer coefficients are compared with different data and correlations proposed in the literature; it has been found that the differences are appreciable. (author)

  12. 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)

  13. Second Law of Thermodynamics Analysis of Transcritical Carbon Dioxide Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    杨俊兰; 马一太; 管海清; 李敏霞

    2004-01-01

    In order to identify the locations of irreversible loss within the transcritical carbon dioxide refrigeration cycle with an expansion turbine, a method with respect to the second law of thermodynamics based on exergy analysis model is applied. The effects of heat rejection pressures, outlet temperatures of gas cooler and evaporating temperatures on the exergy loss, exergy efficiency and the coefficient of performance (COP) of the expansion turbine cycle are analyzed. It is found that the great percentages of exergy losses take place in the gas cooler and compressor. Moreover, heat rejection pressures, outlet temperatures of gas cooler and evaporating temperatures have strong influence on the exergy efficiency, COP and the exergy loss of each component. The analysis shows that there exists an optimal heat rejection pressure corresponding to the maximum exergy efficiency and COP, respectively. The results are of significance in providing theoretical basis for optimal design and the control of the transcritical carbon dioxide system with an expansion turbine.

  14. Comparative study of cycle modification strategies for trans-critical CO2 refrigeration cycle for warm climatic conditions

    Directory of Open Access Journals (Sweden)

    Simarpreet Singh

    2016-03-01

    Full Text Available This paper presents a comparative study of performance of six prominent modifications on the basic trans-critical CO2 refrigeration system to investigate their suitability to high ambient temperature application (35–55 °C. To explore the application in chiller, domestic refrigeration and air cooling the evaporator temperature chosen are −10 °C, 0 °C and 10 °C respectively. In general the cycle modifications have a positive effect on the overall COP of the system. However, to comprehend practicability of these modifications for three application areas, a few other parameters which affect design and operation are also included in the study. These are compressor discharge pressure and temperature, mass flow rate, interstage pressure for multi-stage operation and exergy destruction. Effect of real time constraints like approach temperature, pressure drop in gas cooler, compressors efficieny, degree of superheat, expanders efficiency and effectivenesss of intermediate heat exchanger are also incorporated. Interrelation between these parameters are brought out from the study.

  15. 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.

  16. 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.

  17. Integrated vacuum absorption steam cycle gas separation

    Science.gov (United States)

    Chen, Shiaguo; Lu, Yonggi; Rostam-Abadi, Massoud

    2011-11-22

    Methods and systems for separating a targeted gas from a gas stream emitted from a power plant. The gas stream is brought into contact with an absorption solution to preferentially absorb the targeted gas to be separated from the gas stream so that an absorbed gas is present within the absorption solution. This provides a gas-rich solution, which is introduced into a stripper. Low pressure exhaust steam from a low pressure steam turbine of the power plant is injected into the stripper with the gas-rich solution. The absorbed gas from the gas-rich solution is stripped in the stripper using the injected low pressure steam to provide a gas stream containing the targeted gas. The stripper is at or near vacuum. Water vapor in a gas stream from the stripper is condensed in a condenser operating at a pressure lower than the stripper to concentrate the targeted gas. Condensed water is separated from the concentrated targeted gas.

  18. Performance Analysis of a Double-effect Adsorption Refrigeration Cycle with a Silica Gel/Water Working Pair

    Directory of Open Access Journals (Sweden)

    Atsushi Akisawa

    2010-10-01

    Full Text Available A numerical investigation of the double-effect adsorption refrigeration cycle is examined in this manuscript. The proposed cycle is based on the cascading adsorption cycle, where condensation heat that is produced in the top cycle is utilized as the driving heat source for the bottom cycle. The results show that the double-effect cycle produces a higher coefficient of performance (COP as compared to that of the conventional single-stage cycle for driving temperatures between 100 °C and 150 °C in which the average cycle chilled water temperature is fixed at 9 °C. Moreover, the COP of the double-effect cycle is more than twice that of the single-stage cycle when the temperature reaches 130 °C. It is also observed that the adsorbent mass ratio of the high temperature cycle (HTC to the low temperature cycle (LTC affects the performance of the double-effect adsorption refrigeration cycle.

  19. 回热式制冷循环的热力学分析%Thermodynamic Analysis of Regenerative Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    徐冉冉; 刘红敏

    2016-01-01

    回热循环能够实现较大的回热要求,确保制冷系统的正常运行,提高制冷系统的性能。本文介绍了火用的概念和火用分析方法。对回热式制冷循环各过程进行了热力学分析和计算,并对回热制冷循环和无回热循环进行了比较。通过探讨在循环的各过程的热力学损失,找出了损失最大的过程并提出改进的方法。%Regenerative cycle can achieve large regenerative requirements, ensure the normal operation of the re-frigeration system, and improve the performance of the refrigeration system. This paper introduces the concept of ex-ergy and exergy analysis method. For regenerative refrigeration cycle each process has carried on the analysis and cal-culation of the thermodynamic, and regenerative refrigeration cycle and non regenerative cycle are compared. By dis-cussing thermodynamic loss in circulation of each process, the process of finding out the greatest loss and improved method is put forward.

  20. Performance of Organic Rankine Cycle in Different Refrigerants for Low Temperature Geothermal using Delphi Program

    Directory of Open Access Journals (Sweden)

    Prabowo .

    2010-01-01

    Full Text Available A software has been developed in a Windows-based Delphi programming for analyzing the influence of the transport and thermodynamic properties of the refrigerants on the performance of the Organic Rankine Cycle (ORC. Its user-friendly drag and drop icon format and excellent color graphics make it an interactive tool for teaching and the preliminary design of the ORC system. The research was carried out by analyzing the performance of the system components and the overall ORC based on the several working fluids within R22, R123, R134a and RC318. The pressure of evaporator was varied in two steps 7 and 12 bar, while the condenser was kept constant pressure at 1 bar. The turbine inlet temperature was varied in the range 100 0C to 140 0C where the various isentropic efficiency inputs were applied for pump and turbine. By increasing turbine inlet temperature, R22 has the highest turbine work output and cycle efficiency. Contrary, RC318 has the lowest cycle efficiency and decreases trend with enhancing in turbine inlet temperature. RC318 has low latent heat of vaporization thus vaporizes under relatively very low evaporator heat supply.

  1. Hampson’s type cryocoolers with distributed Joule-Thomson effect for mixed refrigerants closed cycle

    Science.gov (United States)

    Maytal, Ben-Zion

    2014-05-01

    Most previous studies on Joule-Thomson cryocoolers of mixed refrigerants in a closed cycle focus on the Linde kind recuperator. The present study focuses on four constructions of Hampson’s kind miniature Joule-Thomson cryocoolers based on finned capillary tubes. The frictional pressure drop along the tubes plays the role of distributed Joule-Thomson expansion so that an additional orifice or any throttle at the cold end is eliminated. The high pressure tube is a throttle and a channel of recuperation at the same time. These coolers are tested within two closed cycle systems of different compressors and different compositions of mixed coolants. All tests were driven by the same level of discharge pressure (2.9 MPa) while the associated suction pressures and the associated reached temperatures are dependent on each particular cryocooler and on the closed cycle system. The mixture of higher specific cooling capacity cannot reach temperatures below 80 K when driven by the smaller compressor. The other mixture of lower specific cooling capacity driven by the larger compressor reaches lower temperatures. The examined parameters are the cooldown period and the reachable temperatures by each cryocooler.

  2. Advancement of Double Effect Absorption Cycle by Input of Low Temperature Waste Heat

    Science.gov (United States)

    Kojima, Hiroshi; Edera, Masaru; Nakamura, Makoto; Oka, Masahiro; Akisawa, Atsushi; Kashiwagi, Takao

    Energy conservation is becoming important for global environmental protection. New simple techniques of more efficient1y using the waste heat of gas co-generation systems for refrigerationare required. In first report, a new method of using the low temperature waste heat for refrigeration was proposed, and the basic characteristics of the promising methods of recovering waste heat were c1arified. In this report, the more detailed simulation model of the series flow type double effect absorption refrigerator with auxiliary heat exchanger was constructed and the static characteristics were investigated. Then experiments on this advanced absorption refrigerator were carried out, and the results of the calculation and experiments were compared and discussed. Moreover, the betterment of the simulation model of this advanced absorption refrigerator was carried out.

  3. 溴化锂吸收式制冷机模拟实验教学系统设计%Design of simulating experimental teaching system for LiBr absorption-type refrigerating machines

    Institute of Scientific and Technical Information of China (English)

    王美霞; 邵莉; 韩吉田

    2011-01-01

    A simulation experimental system for absorption-type refrigerating machines was designed based on the ACAD and Visual Basic software. The use of the system can not only complete structure model of absorption-type refrigerating machine and thermal calculation for the absorption-type refrigerating cycle, but also simulate the PID control system and realize intelligent controls. The experimental system has the friendly man-machine interface beneficial to the students' operating and understanding, thereby decreasing the students' difficulties in learning and improving the experiment teaching effect.%利用ACAD和Visual Basic软件对溴化锂吸收式制冷机组进行实验教学仿真系统设计,可以完成机组结构剖析、循环热力计算和控制回路模拟等演示实验.实验系统采用友好的人机交互界面,便于操作和理解,既降低了学习难度,又提高了实验教学的效果.

  4. A detailed analysis of entropy production and improvement of the thermodynamic cycle of an adsorption refrigerating plant

    Science.gov (United States)

    Okunev, B. N.; Safonov, M. S.

    2006-07-01

    A thermodynamic analysis of an adsorption refrigerating plant with closed loops for a working substance and auxiliary liquid heat carrier has been carried out in application to the adsorption pair “water-CaCl2 impregnated into the pores of a silica gel.” Using the obtained periodic solutions of the system of energy-balance equations for the heat carrier and the sorbent layer, the most thermodynamically effective modes of operation of the refrigerating plant have been determined as functions of governing parameters. The entropy production in various modules of the plant is calculated, and the main sources of entropy generation are revealed. This made it possible to suggest an improved scheme of an adsorption refrigerating cycle with regenerative heat exchangers connected at the inlet and outlet from the adsorbers. The possibility of a considerable increase in the coefficient of thermodynamic efficiency in such a system has been justified.

  5. A Theoretical Comparative Study on Nanorefrigerant Performance in a Single-Stage Vapor-Compression Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Melih Aktas

    2015-01-01

    Full Text Available The topic of nanofluid heat transfer is certainly of interest to the heat transfer community. Nanorefrigerants are a type of nanofluids that are mixtures of nanoparticles and pure refrigerants. This paper focuses on five different nanorefrigerants with Al2O3 nanoparticles and their pure fluids: R12, R134a, R430a, R436a, and R600a. The coefficient of performance (COP and compressor work for various evaporation and condensation temperatures are investigated. A method is developed to estimate the performance characteristics of nanorefrigerants in the refrigerant cycles for the nonsuperheating/subcooling case and superheating/subcooling case. The enthalpy of nanorefrigerants is obtained through the density. The validation process of the proposed method was accomplished with the available data in the literature. The results indicate that COP is enhanced by adding nanoparticles to the pure refrigerant and maximum values obtained using the R600a/Al2O3 mixture.

  6. Performance analysis of 404a/508b Cascade Refrigeration cycle for low temperature

    Directory of Open Access Journals (Sweden)

    DEVANSHU PYASI

    2011-08-01

    Full Text Available This paper presents analytical results of analyzing blends of Hfc refrigerants such as 404a and 508b in Cascade Refrigeration System. Refrigerant blend 508b is a low boiling refrigerant and advantageous in low stage of cascade refrigeration system whereas 404a is used in high stage of cascade refrigeration system because of its high boiling point which is suitable for high temperature circuit. The analysis includes three basic parameters as :Evaporator temperature(Te,Condenser temperature (Tc, and temperature difference in cascade condenser (Dt .These parameters are varied one by one up to a limited range keeping other parameters constant and theeffect of these parameters on system COP , exergetic efficiency, mass flow ratio etc is analyzed. Analysis results also give the optimum values of the evaporator, condenser and cascade condenser temperature.

  7. 太阳能驱动吸收式与吸附式制冷技术的比较分析研究%Comparison and Analytical Investigation of Solar Powered Absorption Refrigeration and Adsorption Refrigeration

    Institute of Scientific and Technical Information of China (English)

    朱斌祥; 孙李; 喻志强; 徐军; 牛晓文

    2016-01-01

    介绍了太阳能吸收式制冷技术与吸附式制冷技术,并对这2种技术的原理特性、应用领域、工质对、系统结构、效率损失等问题进行了比较分析研究。研究表明:吸收式技术制冷系数高,但吸附式制冷对驱动热源的温度要求低;2种制冷技术的制冷性能与集热器、发生器、吸收器、吸附床和工质对等的特性密切相关。本文为提高太阳能制冷的效率和应用领域、促进太阳能制冷技术的发展提供了一定的技术方向和理论参考。%The current technology of solar absorption refrigeration and adsorption refrigeration were introduced and compared in aspects of principle and properties,application area,working medium pairs,systematic structure and efficiency.It was shown that refrigeration coefficient of absorption refrigeration is higher,however adsorption refrigeration has lower requirement for driving heat source.Furthermore performance of these two refrigeration technology was highly related to collector,generator,absorber,adsorbent bed,working medium pairs and etc.This paper offers technical direction and theoretical reference for efficiency improvement, broaden of application and technology development of solar powered refrigeration.

  8. 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.

  9. 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.

  10. Computational Analysis of Silica gel-Water Adsorption Refrigeration Cycle with Mass Recovery

    Science.gov (United States)

    Akahira, Akira; Alam, K. C. Amanul; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    The study aims at clarifying the performance of silica gel-water adsorption refrigeration cycle with mass recovery process.Two kinds of heat exchanger were examined and the performances were compared with each other. One type of heat exchanger was a spiral tube and it was immersed in a low temperature thermostatic bath. The other was coil-shaped double tube heat exchanger using two tubes. The emulsion was circulated to make ice continuously. These systems were operated under various cooling conditions (flow rates of the emulsion and brine temperatures). The effects of the tube materials (fluororesin and non-fluororesin) and thickness were also examined. Slurry ice was formed continuously without adhesion of ice to the cooling wall under certain conditions. Using the fluororesin tube prevented ice from the adhesion and it enlarged the range of the cooling conditions under which slurry ice was formed continuously. Furthermore, by making thickness of the tube thinner and increasing the heat transfer coefficient on the outside of the tube, ice was made continuously without lowering the rate of ice formation at a higher brine temperature.

  11. 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...

  12. 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.

  13. Thermoeconomic Analysis of a Single and Double-Effect LiBr/H2O Absorption Refrigeration System

    Directory of Open Access Journals (Sweden)

    Silvia Azucena Nebra

    2009-06-01

    Full Text Available

    The aim of this work is to carry out a thermoeconomic analysis of a single and double-effect LiBr/H2O absorption refrigeration system. The methodology of functional analysis with negentropy is used. The exergetic cost of the main product, the cooling cost, was calculated as a function of the exergy of the heat source. Two cases were analyzed for each system: the first considers a direct-fired system while the second considers a hot-water driven system for the single-effect system and a steam-driven system for the double effect system as part of a cogeneration system. As expected, the resultant exergetic cost of the main product was higher for the direct-fired system.

    • This paper is an updated version of a paper published in the ECOS'08 proceedings. 

  14. 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)

  15. Additional parameter in evaluating the performance of intermittent solar refrigerators

    Energy Technology Data Exchange (ETDEWEB)

    El-Shaarawi, M.A.I.; Ramadan, R.A.

    1988-01-01

    The parameters which have been considered by previous investigators in evaluating the performance of intermittent solar refrigerators are: the maximum attainable generator temperature, the condensing temperature and the initial solution conditions. The present investigation shows that an additional parameter, viz. the temperature of the condensate at the beginning of the absorption process, should be taken into consideration. Results of a thermodynamic analysis for the theoretical constant-temperature-absorption refrigeration cycle reveal that this parameter has considerable influence on the performance of intermittent solar refrigerators utilizing an ammonia-water solution as the working fluid.

  16. 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.

  17. Simple uniaxial pressure device for ac-susceptibility measurements suitable for closed cycle refrigerator system.

    Science.gov (United States)

    Arumugam, S; Manivannan, N; Murugeswari, A

    2007-06-01

    A simple design of the uniaxial pressure device for the measurement of ac-susceptibility at low temperatures using closed cycle refrigerator system is presented for the first time. This device consists of disc micrometer, spring holder attachment, uniaxial pressure cell, and the ac-susceptibility coil wound on stycast bobbin. It can work under pressure till 0.5 GPa and at the temperature range of 30-300 K. The performance of the system at ambient pressure is tested and calibrated with standard paramagnetic salts [Gd(2)O(3), Er(2)O(3), and Fe(NH(4)SO(4))(2)6H(2)O], Fe(3)O(4), Gd metal, Dy metal, superconductor (YBa(2)Cu(3)O(7)), manganite (La(1.85)Ba(0.15)MnO(3)), and spin glass material (Pr(0.8)Sr(0.2)MnO(3)). The performance of the uniaxial pressure device is demonstrated by investigating the uniaxial pressure dependence of La(1.85)Ba(0.15)MnO(3) single crystal with P||c axis. The Curie temperature (T(c)) decreases as a function of pressure with P||c axis (dT(c)dP(||c axis)=-11.65 KGPa) up to 46 MPa. The design is simple, is user friendly, and does not require pressure calibration. Measurement can even be made on thin and small size oriented crystals. The failure of the coil is remote under uniaxial pressure. The present setup can be used as a multipurpose uniaxial pressure device for the measurement of Hall effect and thermoelectric power with a small modification in the pressure cell.

  18. 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.

  19. 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.

  20. 复合制冷循环间冷系统制冷剂/工质的选择论证%A Selection Demonstration of Refrigerant/Medium for Compound Refrigerating Cycle of Indirect Air Cooling System

    Institute of Scientific and Technical Information of China (English)

    杨善让; 雷扬; 赵波; 盛杰; 陈立军

    2012-01-01

    该文旨在从目前80余种制冷剂(包括替代工质)中筛选出能满足复合制冷循环间冷系统f以下简称复间冷)要求的中间传热介质(制冷剂/工质)。筛选步骤如下:1)按制冷剂的臭氧损耗潜势和全球变暖潜势挑选出满足环保要求的“环保型制冷剂”;2)根据环保型制冷剂的物性对复间冷要求的满足程度,挑出合适度比较高的若干种;3)从前两轮筛选出的制冷剂/工质挑出做功能力最大者。最终氨成为3轮筛选唯一胜出的自然物质。考虑到氨的气味对人的呼吸道有刺激性,条件具备时可燃可爆,故再次仔细分析了其安全性,指出其燃爆可防、易防,拟定了相应防范措施,并列举了应用实例。全文结论为:氨物性对复间冷的合适度最高,环境最友好,安全可靠,性价比高。作为复间冷的制冷剂/工质,氨虽非最佳,但目前尚无更佳的替代物。%This paper aims at sieving out the intermediate heat transfer medium (namely refrigerant/medium) for the compound refrigerating cycle from more than 80 refrigerants, which are capable of meeting the compound refrigerating cycle's demands. The sieve course are comprised of 3-steps: 1)According to the values of ozone depletion potential (ODP) and global warming potential (GWP) of refrigerants sifted the so called "environment protection type refrigerant" which meet the environment protection requirements; 2) Based on property parameters of the environment protection type refrigerants/ mediums select those refrigerants which are in accord with requirements of compound refrigerating cycle of indirect air cooling system; 3)The third criterion is that the power capability of medium in inverse refrigerating cycle is the maximum of all the mediums selected by the first and second round of the sifting. At last, the ammonia became the only natural materials which satisfy all

  1. Effect of Internal Heat Recovery in Ammonia-Water Absorption Cooling Cycles: Exergy and Structural Analysis

    Directory of Open Access Journals (Sweden)

    Miquel Nogués

    2009-03-01

    Full Text Available First and second law analysis have been conducted for three low temperature driven ammonia-water absorption cooling cycles with increasing internal heat recovery. Based on the results of exergy analysis the structural analysis has been achieved. The obtained Coefficients of Structural Bonds (CSB consider how the irreversibility of the whole cycle is affected by a change in the irreversibility related to an efficiency improvement of a single component. Trends for the different configurations are similar, while quantitative differences among the main heat exchangers are considerable. The highest values of the CSB are found for the refrigerant heat exchanger. Also the evaporator, the condenser, the generator and the absorber show values higher than unity. The lowest CSB’s are obtained in the solution heat exchanger. In general, CSB’s decrease with increasing efficiency. That means that for very efficient heat exchangers, a further improvement looks less attractive. The dephlegmator is an exception as it shows a singularity of the CSB value due to its complex interactions with the other components. Once the CSB’s are obtained for the main components, they can be used in the structural method of the thermoeconomic optimisation. This method enables us to find the optimum design of a component in a straightforward calculation.

  2. Study of thermodynamic properties of HFC refrigerant mixtures for Loretz-cycled niew generation air-conditioning equipment; Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsu rikigaku seishitsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, K.; Sato, H. [Keio University, Tokyo (Japan). Faculty of Science and Technology

    1997-02-01

    This paper describes thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipment. Equipment has been completed for simultaneous measurement of density and vapor-liquid equilibrium property, accurate measurement of latent heat of vaporization, and accurate measurement of specific heat at constant pressure in liquid phase. Final adjustment and preliminary measurements are currently conducted. Through analytical investigation using actually measured data of thermodynamic properties of HFC refrigerant mixtures, five state equations were obtained, i.e., modified Peng-Robinson state equation which can reproduce the vapor-liquid equilibrium property of refrigerant mixtures, modified Patel-Teja state equation, Helmholtz function type state equation which is applicable in the whole fluid region of refrigerant mixtures, and so on. An evaluation test equipment has been fabricated as a trial for Lorentz-cycled air-conditioning equipments using HFC refrigerant mixtures, and demonstration test is conducted to confirm the validity. 9 refs., 5 figs.

  3. 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.

  4. 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.

  5. Shock isolator for operating a diode laser on a closed-cycle refrigerator

    Science.gov (United States)

    Jennings, D. E. (Inventor)

    1979-01-01

    A diode laser mounted within a helium refrigerator is mounted using a braided copper ground strap which provides good impact shock isolation from the refrigerator cold-tip while also providing a good thermal link to the cold-tip. The diode mount also contains a rigid stand-off assembly consisting of alternate sections of nylon and copper which serve as cold stations to improve thermal isolation from the vaccum housing mounting structure. Included in the mount is a Pb-In alloy wafer inserted between the cold-tip and the diode to damp temperature fluctuations occurring at the cold-tip.

  6. Experimental study on solar-powered adsorption refrigeration cycle with activated alumina and activated carbon as adsorbent

    Directory of Open Access Journals (Sweden)

    Himsar Ambarita

    2016-03-01

    Full Text Available Typical adsorbent applied in solar-powered adsorption refrigeration cycle is activated carbon. It is known that activated alumina shows a higher adsorption capacity when it is tested in the laboratory using a constant radiation heat flux. In this study, solar-powered adsorption refrigeration cycle with generator filled by different adsorbents has been tested by exposing to solar radiation in Medan city of Indonesia. The generator is heated using a flat-plate type solar collector with a dimension of 0.5 m×0.5 m. Four cases experiments of solar-powered adsorption cycle were carried out, they are with generator filled by 100% activated alumina (named as 100AA, by a mixed of 75% activated alumina and 25% activated carbon (75AA, by a mixed of 25% activated alumina and 75% activated carbon (25AA, and filled by 100% activated carbon. Each case was tested for three days. The temperature and pressure history and the performance have been presented and analyzed. The results show that the average COP of 100AA, 75AA, 25AA, and 100AC is 0.054, 0.056, 0.06, and 0.074, respectively. The main conclusion can be drawn is that for Indonesian condition and flat-plate type solar collector the pair of activated carbon and methanol is the better than activated alumina.

  7. Analysis of Decentralized Control for Absorption Cycle Heat Pumps

    DEFF Research Database (Denmark)

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

    2015-01-01

    Email Print Request Permissions This paper investigates decentralized control structures for absorption cycle heat pumps and a dynamic nonlinear model of a single-effect LiBr-water absorption system is used as case study. The model has four controllable inputs, which can be used to stabilize...... the operation of the heat pump under different load conditions. Different feasible input-output pairings are analyzed by computation of relative gain array matrices and scaled condition numbers, which indicate the best pairing choice and the potential of each input-output set. Further, it is possible...... to minimize the effect of cross couplings and improve stability with the right pairing of input and output. Simulation of selected candidate input-output pairings demonstrate that decentralized control can provide stable operation of the heat pump....

  8. Study of a Vuilleumier cycle cryogenic refrigerator for detector cooling on the limb scanning infrared radiometer

    Science.gov (United States)

    Russo, S. C.

    1976-01-01

    A program to detect and monitor the presence of trace constituents in the earth's atmosphere by using the Limb Scanning Infrared Radiometer (LSIR) is reported. The LSIR, which makes radiometric measurements of the earth's limb radiance profile from a space platform, contains a detector assembly that must be cooled to a temperature of 65 + or - 2 K. The feasibility of cooling the NASA-type detector package with Vuilleumier (VM) cryogenic refrigerator was investigated to develop a preliminary conceptual design of a VM refrigerator that is compatible with a flight-type LSIR instrument. The scope of the LSIR program consists of analytical and design work to establish the size, weight, power consumption, interface requirements, and other important characteristics of a cryogenic cooler that would meet the requirements of the LSIR. The cryogenic cooling requirements under the conditions that NASA specified were defined. Following this, a parametric performance analysis was performed to define the interrelationships between refrigeration characteristics and mission requirements. This effort led to the selection of an optimum refrigerator design for the LSIR mission.

  9. Static Characteristics of Absorption Chiller-Heater Supplying Cold and Hot Water Simultaneously

    Science.gov (United States)

    Inoue, Naoyuki; Irie, Tomoyoshi

    Absorption chiller-heaters which can supply both chilled water and hot water at the same time, are used for cooling and heating air conditioning systems. In this paper, we classified absorption cold and hot water generating cycles and control methods, studied these absorption cycles by cycle simulation. In economizer cycle, condensed refrigerant which heats hot water is transported to cooling cycle and used effectively for cooling chilled water, Concerning with transported condensed refrigerant, there are two methods, all condensed refrigerant or required refrigerant for cooling are transported to cooling cycle, and required refrigerant method is better for energy saving. Adding improvement of solution control to this economizer cycle, simultaneous cold and hot water supplying chiller-heaters have good characteristics of energy saving in the all region.

  10. 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.

  11. Evaluation of combined effect of organic and inorganic inhibitors on the metals used in absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, M.H.; Back, K.K. [Hyundai Heavy Industries Co. Ltd., Ulsan (Korea, Republic of). Hyundai Industrial Research Inst.

    1999-11-01

    To develop environment-friendly inhibitors for the metals used in the absorption refrigeration system, inhibition efficiencies of six different combinations of inhibitors were evaluated in 64wt%LiBr solution at 160 C. Double and triple combinations of inhibitors, such as lithium molybdate (Li{sub 2}MoO{sub 4}, inorganic), lithium hydroxide (LiOH, inorganic), and benzotriazole (BTA, organic) were evaluated for their efficiencies in corrosion inhibition of copper and mild steel. Results from weight-loss tests showed that the double inhibitor combinations were less effective for topper than for mild steel, whereas the triple inhibitor combination of 0.2wt%LiOH + 0.02wt%Li{sub 2}MoO{sub 4} + 0.05wt%BTA was most effective and it showed much better performance than any other double inhibitor combinations including the commercial products. This formula, of which inhibition efficiency was predicted to be about 83% for copper and 96% for mild steel, can replace the commercial grade inhibitors containing lithium chromate (Li{sub 2}CrO{sub 4})

  12. Experimental investigation of mass transfer performance with some random packings for ammonia rectification in ammonia-water absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Sieres, Jaime; Fernandez-Seara, Jose [Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, University of Vigo, Campus Lagoas-Marcosende No 9, 36310 Vigo (Spain)

    2007-07-15

    In ammonia water absorption refrigeration systems (AARS) a high efficiency purification process to remove the water content from the generated vapour is of great importance. One type of equipment to carry out this process is a packed column. Any type of detailed analysis of a packed column requires the calculation of mass transfer coefficients. Therefore, the correlations to obtain these coefficients become an essential tool for an accurate analysis and design of these devices. An experimental facility has been designed and built to analyze the ammonia-water rectification process in packed columns. In this paper a brief description of the experimental facility is given and the variables required to analyze the column performance are explained. An analytical method to determine mass transfer coefficients from the experimental data is developed. Results of mass transfer coefficients for 15 mm glass Raschig rings, (1)/(2){sup ''} ceramic Berl saddles and (1)/(2)'' ceramic Novalox saddles random packings are reported. The experimental results are compared with different mass transfer correlations proposed in the literature. In the paper corrected correlations are proposed for the packings considered. These correlations could be used to analyze and design a packed column for AARS. (author)

  13. Feasibility and Basic Design of Solar Integrated Absorption Refrigeration for an Industry

    KAUST Repository

    Akhtar, Saad

    2015-08-28

    This paper presents a review of existing solar cooling technologies and a feasibility study of a solar absorption cooling system for a packaging facility at Tetrapak Lahore, Pakistan. The review includes brief description of existing chiller technologies and solar collectors. The case study includes analysis of the solar potential and design of the cooling system at considered site. The design calculations upon which the feasibility analysis is carried out are solar collector area and type, cooling capacity, cooling area. A comparison is made between solar cooling potential of Pakistan and existing sites all across the globe. Finally an economic analysis is carried out to demonstrate the financial viability of the new cooling system.

  14. Predicting CO2 Solubility in Imidazole Ionic Liquids for Use in Absorption Refrigeration Systems by Using the Group Contribution Equation of State Method

    Science.gov (United States)

    Wu, Wei-Dong; Wu, Jun; Hou, Yong; Su, Lin; Zhang, Hua

    2017-09-01

    Traditional absorption refrigeration such as H2O-LiBr- and NH3-H2O-based refrigeration has limited applications because of several issues, including crystallization, corrosion, and large volume. CO2-ionic liquids (ILs) as new absorption working pairs were investigated in this study. The objective was to use the group contribution equation of state (GC-EOS) method to predict the solubilities of binary systems containing high-pressure CO2-imidazole bis(trifluoromethanesulfonimide) ILs and to investigate the applicability and accuracy of the GC-EOS model. The results showed that at pressures up to 11.0 MPa and temperatures of 273 K to 400 K, the CO2 solubility in the ILs increased with increasing system pressure but decreased with increasing temperature, and its variation rate was lower at higher pressures or temperatures. Also, CO2 solubility increased in the order of [emim][Tf2N] families resulted in higher CO_{2 } solubility. The model prediction of CO2 solubility in the four different ILs showed reasonable consistency with the corresponding experimental results from the literature; the largest deviation was 5.7 % for CO2-[emim][Tf2N]. Therefore, it can be concluded that the GC-EOS model is a promising theoretical solution that can be used to search for suitable CO2-IL working pairs for absorption refrigeration systems.

  15. Evaluation of minimum desorption temperatures of thermal compressors in adsorption refrigeration cycles

    Energy Technology Data Exchange (ETDEWEB)

    Saha, B.B.; El-Sharkawy, I.I.; Chakraborty, A.; Koyama, S.; Srinivasan, K. [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen Kasuga, Fukuoka 816-8580 (Japan); Banker, N.D.; Dutta, P. [Department of Mechanical Engineering, Indian Institute of Science, Bangalore (India); Prasad, M. [Thermal Systems Division, ISRO Satellite Centre, Bangalore (India)

    2006-11-15

    The purpose of this paper is to identify the minimum desorption temperatures required to operate thermally driven adsorption beds of a solid sorption refrigeration system. The method is based on the evaluation of uptake efficiency of the adsorption bed and estimating there from conditions under which the compressor ceases to provide any throughput. The difference in the densities of the refrigerant between the inlet and outlet, the adsorption characteristics of the adsorbate-refrigerant pair and the void volume in the thermal compressor are the contributors to the manifestation of the desorption state. Among them, the void volume is a controllable parameter whose role is analogous to the clearance volume in a positive displacement compressor. The methodology has been tested out with three systems, namely, silica gel+water, activated carbon fiber+ethanol and activated carbon+HFC 134a systems. It is shown that waste heat at as low as 60{sup o}C can operate these systems which make them good energy conservation devices through recovery of low grade process waste heat. (author)

  16. Effect of Suction Nozzle Pressure Drop on the Performance of an Ejector-Expansion Transcritical CO2 Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2014-08-01

    Full Text Available The basic transcritical CO2 systems exhibit low energy efficiency due to their large throttling loss. Replacing the throttle valve with an ejector is an effective measure for recovering some of the energy lost in the expansion process. In this paper, a thermodynamic model of the ejector-expansion transcritical CO2 refrigeration cycle is developed. The effect of the suction nozzle pressure drop (SNPD on the cycle performance is discussed. The results indicate that the SNPD has little impact on entrainment ratio. There exists an optimum SNPD which gives a maximum recovered pressure and COP under a specified condition. The value of the optimum SNPD mainly depends on the efficiencies of the motive nozzle and the suction nozzle, but it is essentially independent of evaporating temperature and gas cooler outlet temperature. Through optimizing the value of SNPD, the maximum COP of the ejector-expansion cycle can be up to 45.1% higher than that of the basic cycle. The exergy loss of the ejector-expansion cycle is reduced about 43.0% compared with the basic cycle.

  17. A four-level quantum refrigeration cycle%四能级量子制冷循环

    Institute of Scientific and Technical Information of China (English)

    何弦; 何济洲; 肖宇玲

    2012-01-01

    本文提出以两个qubit量子纠缠系统为工质的四能级制冷循环模型,基于量子热力学第一定律和热纠缠概念,分析了在循环中系统与外界交换的热量、输入功、制冷系数等热力学参数与量子纠缠之间的关系,结果表明:制冷系数等高线图是环状曲线,随纠缠比r增加而非单调变化;当相互作用常数J比较小时,量子制冷机运行区间在c_1〉c_2,当增加J值时,制冷机运行区间在c1〉c2和c1%A four-level entangled quantum refrigeration cycle working with a two-qubit entangled system is proposed in this paper.Based on the first law of quantum thermodynamics and the concept of thermal entanglement,the relation between the quantum entanglement and the several thermodynamic quantities such as the heat transfer,the input work and the coefficient of performance is analyzed.It is found that the isoline of the coefficient of performance is the loop line and it no longer monotonically changes with the ratio of entanglement;in a small exchange constant J the operation region of the refrigerator is c1 〉 c2 and in a larger exchange constant J the operation region of the refrigerator may be c1 〉 c2 or c1 〈c2;the maximal coefficient of performance increases as the exchange constant increases.

  18. Comparative evaluation of the intermediate systems employed in two-stage refrigeration cycles driven by compound compressors

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-03-15

    This work presents an experimental evaluation, from an energy analysis point of view, for two of the most used inter-stage systems in two-stage vapour compression cycles driven by compound compressors: the direct liquid injection and subcooler systems. The evaluation considers the two-stage cycle with no intermediate systems as reference cycle, and was performed on a plant driven by a compound compressor using the refrigerant R404A for an evaporating temperature range of -36 to -20 C and for a condensing temperature range of 30-47 C. The analysis of the results shows that the inter-stage systems determine the performance of the energy parameters, which are discussed in the paper. The configuration yielding the best results was the two-stage compression cycle with subcooler, since the cooling capacity and COP values for this configuration were the highest. Conversely, the two-stage compression cycle working with direct liquid injection showed lower performance from an energy point of view, though this configuration allows a substantial reduction of the discharge temperature. (author)

  19. Application of a solar refrigeration system by absorption for the air conditioning of buildings

    Energy Technology Data Exchange (ETDEWEB)

    Machielsen, Cees H. M [Delft University of Technology, Mekelweg (Netherlands); Hagendijk, Andre E [Consultancy and Research (Netherlands)

    2000-07-01

    This paper describes the Sofri project, a cooperation between Ceeran Ltd and The Delft University of Technology. The main objective of this project is to develop the necessary knowledge and experience to commercialize solar-assisted air conditioning and dehumidification systems in the Dutch Caribbean. The project is motivated by the present needs of the Dutch Caribbean for renewable energy sources and the fact that the Caribbean has a high and uniform insolation throughout the year. Furthermore, hotels and offices in this area use more than 40% of their energy for air-conditioning purposes. Therefore solar-assisted air conditioning systems are a logic approach in reducing the energy demand and to lower the peak electricity reducing the energy demands for the local power station. Ceeran Ltd has the objective to reach full commercialization of the proposed technologies in the Dutch Caribbean. The research is concentrated on liquid absorption machines and solar collection systems such as flat plates with selective surfaces, heat pipe evacuated tubes flat plate collectors, and Compound Parabolic Concentrators. The first demonstration unit is planned to be installed in an office building in Curacao. The installation consists of a 35 kW LiBr/H{sub 2}O absorption machine driven by 100 m{sup 2} flat pate collectors with a gas backup system. The system will provide comfort air-conditioning for this these type of office buildings during daytime. [Spanish] Este documento describe el proyecto SOFRI, una cooperacion entre Ceeran, Ltd, y la Universidad Tecnologica del Delft. El principal objetivo de este proyecto es el de desarrollar el conocimiento necesario y la experiencia para comercializar los sistemas de aire acondicionado y deshumidificacion ayudados por la energia solar en el Caribe Holandes. Este proyecto ha sido motivado por las actuales necesidades del Caribe Holandes de fuentes de energia renovable y por el hecho de que el Caribe tiene una alta y uniforme insolacion

  20. Absorption Cycle Heat Pump Model for Control Design

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  1. Solutions for Liquid Nitrogen Pre-Cooling in Helium Refrigeration Cycles

    CERN Document Server

    Wagner, U

    2000-01-01

    Pre-cooling of helium by means of liquid nitrogen is the oldest and one of the most common process features used in helium liquefiers and refrigerators. Its two principle tasks are to allow or increase the rate of pure liquefaction, and to permit the initial cool-down of large masses to about 80 K. Several arrangements for the pre-cooling process are possible depending on the desired application. Each arrangement has its proper advantages and drawbacks. The aim of this paper is to review the possible process solutions for liquid nitrogen pre-cooling and their particularities.

  2. Neon helium mixtures as a refrigerant for the FCC beam screen cooling: comparison of cycle design options

    Science.gov (United States)

    Kloeppel, S.; Quack, H.; Haberstroh, C.; Holdener, F.

    2015-12-01

    In the course of the studies for the next generation particle accelerators, in this case the Future Circular Collider for hadron-hadron interaction (FCC-hh), different aspects are being investigated. One of these is the heat load on the beam screen, which results mainly from the synchrotron radiation. In case of the FCC-hh, a heat load of 6 MW is expected. The heat has to be absorbed at 40 to 60 K due to vacuum restrictions. In this range, refrigeration is possible with both helium and neon. Our investigations are focused on a mixed refrigerant of these two components, which combines the advantages of both. Especially promising is the possible substitution of the oil flooded screw compressors by more efficient turbo compressors. This paper investigates different flow schemes and mixture compositions with respect to complexity and efficiency. Furthermore, thermodynamic aspects, e.g. whether to use cold or warm secondary cycle compressors are discussed. Additionally, parameters of the main compressor are established.

  3. 制冷剂循环性能对比及物性分析%Comparison Analysis of Cycle Performance and Characteristic Parameters of Refrigerants

    Institute of Scientific and Technical Information of China (English)

    王洪利; 田景瑞; 刘慧琴

    2012-01-01

    In the refrigeration and air conditioning and heat pump industry, freon - based ODP and GWP refrigerant problems, the systems energy efficiency and alternative refrigerants become a hot topic in the forefront of modem technology. Through an extensive literature research and theoretical analysis of the current commonly used refrigerant cycle performance of the basic physical properties and gives a more comprehensive analysis and the basic properties of the lubricant and the refrigerant and oil solubility, gave in-depth study, as related to the screening and alternative refrigerants to provide basic data.%在制冷空调和热泵行业,基于氟利昂制冷剂的ODP和GWP问题,使系统的节能和制冷剂的替代成为当代科技前沿的热点.本文通过调研以及理论分析,对当前常用制冷剂的基本物性和循环性能给出了一个较全面的分析,并且对润滑油基本物性以及制冷剂与润滑油互溶问题作了深入研究,为相关制冷剂的筛选和替代研究提供了理论基础.

  4. A new type mixture refrigeration auto-cascade cycle with partial condensation and separation reflux exchanger and its preliminary experimental test

    Science.gov (United States)

    Wu, J. F.; Gong, M. Q.; Liu, J. L.; Luo, E. C.; Qi, Y. F.; Hu, Q. G.

    2002-05-01

    A new type of mixture refrigeration cycle with reflux exchanger is presented in this paper. In this cycle, a new type of L-V separator with inner heat and mass transfer is employed to replace the combination of conventional L-V separator or complicated rectifier and succeeding heat exchanger used in traditional auto-cascade cycle or Kleemenko cycle. A prototype is developed based on this refrigeration cycle. The thermodynamic performance is discussed as well as some other specifications such as cost, reliability, etc. The experimental results show that this prototype can reach 74 W at 135 K and 265 W at 171 K with a nominal input power of 1.5 HP.

  5. A Possible 1.8 K Refrigeration Cycle for the Large Hadron Collider

    CERN Document Server

    Millet, F; Tavian, L; Wagner, U

    1998-01-01

    The Large Hadron Collider (LHC) under construction at the European Laboratory for Particle Physics, CERN, will make use of superconducting magnets operating below 2.0 K. This requires, for each of the eight future cryogenic installations, an isothermal cooling capacity of up to 2.4 kW obtained by vaporisation of helium II at 1.6 kPa and 1.8 K. The process design for this cooling duty has to satisfy several demands. It has to be adapted to four already existing as well as to four new refrigerators. It must cover a dynamic range of one to three, and it must to allow continuous pump-down from 4.5 K to 1.8 K. A possible solution, as presented in this paper, includes a combination of cold centrifugal and warm volumetric compressors. It is characterised by a low thermal load on the refrigerator, and a large range of adaptability to different operation modes. The expected power factor for 1.8 K cooling is given, and the proposed control strategy is explained.

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

    Directory of Open Access Journals (Sweden)

    Jonathan Ibarra-Bahena

    2014-02-01

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

  7. Performance studies on mechanical + adsorption hybrid compression refrigeration cycles with HFC 134a

    Energy Technology Data Exchange (ETDEWEB)

    Banker, N.D.; Dutta, P.; Srinivasan, K. [Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560 012 (India); Prasad, M. [Thermal Systems Division, ISRO Satellite Centre, Bangalore 560 017 (India)

    2008-12-15

    This paper presents the results of an investigation on the efficacy of hybrid compression process for refrigerant HFC 134a in cooling applications. The conventional mechanical compression is supplemented by thermal compression using a string of adsorption compressors. Activated carbon is the adsorbent for the thermal compression segment. The alternatives of bottoming either mechanical or thermal compression stages are investigated. It is shown that almost 40% energy saving is realizable by carrying out a part of the compression in a thermal compressor compared to the case when the entire compression is carried out in a single-stage mechanical compressor. The hybrid compression is feasible even when low grade heat is available. Some performance indictors are defined and evaluated for various configurations. (author)

  8. 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.

  9. Energetic and Exergetic Analysis of an Ejector-Expansion Refrigeration Cycle Using the Working Fluid R32

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2015-07-01

    Full Text Available The performance characteristics of an ejector-expansion refrigeration cycle (EEC using R32 have been investigated in comparison with that using R134a. The coefficient of performance (COP, the exergy destruction, the exergy efficiency and the suction nozzle pressure drop (SNPD are discussed. The results show that the application of an ejector instead of a throttle valve in R32 cycle decreases the cycle’s total exergy destruction by 8.84%–15.84% in comparison with the basic cycle (BC. The R32 EEC provides 5.22%–13.77% COP improvement and 5.13%–13.83% exergy efficiency improvement respectively over the BC for the given ranges of evaporating and condensing temperatures. There exists an optimum suction nozzle pressure drop (SNPD which gives a maximum system COP and volumetric cooling capacity (VCC under a specified condition. The value of the optimum SNPD mainly depends on the efficiencies of the ejector components, but is virtually independent of evaporating temperature and condensing temperature. In addition, the improvement of the component efficiency, especially the efficiencies of diffusion nozzle and the motive nozzle, can enhance the EEC performance.

  10. 烟气型吸收式制冷机的变工况特性研究%Off-Design Performance of an Exhaust-Fired Absorption Refrigerator

    Institute of Scientific and Technical Information of China (English)

    郑剑娇; 郭培军; 隋军; 韩巍; 石文星; 金红光

    2012-01-01

    基于分布式冷热电联产系统变工况运行的实际需要,建立了烟气型双效溴化锂吸收式制冷机的变工况模型。制冷机变工况模拟计算时,保持浓溶液流量及换热系数(高压发生器除外)不变,得到了烟气进口温度、烟气流量及冷却水进口温度变化时的制冷机各重要性能参数曲线,发现当烟气流量低于50%时,COP下降较快,冷却水进口温度降低时有利于制冷机运行,但是要注意防止浓溶液结晶。制冷机额定工况模拟计算时,与已有文献进行对比,验证模型的可靠性。%This paper proposed a mathematical model to simulate the off-design performance of an exhaust-fired double-effect absorption refrigerator in a CCHP (Combined cooling, heating and power) system. Effects of exhaust gas inlet temperature and flow rate , cooling water inlet temperature on the performance of absorption refrigerator have been investigated, with the assumptions of constant value of strong solution flow rate and heat transfer coefficients. When the exhaust gas flow ratio is below 50%, COP drops quickly. The decrease of cooling water inlet temperature can improve the performance of absorption refrigerator, with the prevention of solution crystallization. The model has been compared with a published model to validate.

  11. Comparative Study on Solar Collector’s Configuration for an Ejector-Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Raffles Senjaya

    2008-05-01

    Full Text Available Solar collector’s configuration plays important role on solar-powered refrigeration systems to work as heat source for generator. Three types of solar collector consisting of flat plate, evacuated tube, and compound parabolic solar collectors are compared to investigate their performances. The performances consist of the behavior of heat which can be absorbed by the collectors, heat loss from the collectors and outlet temperature of working fluid at several slopes of the solar collectors. The new accurate analysis method of heat transfer is conducted to predict the performance of the solar collectors. The analysis is based on several assumptions, i.e. sky condition at Bandung is clear and not raining from 08.00 until 17.00 and thermal resistance at cover and absorber plate is negligible. The numerical calculation results confirm that performance of the evacuated tubes solar collector at the same operating conditions is higher than the others. For the case of an evacuated-tubes solar collector system with aperture area of 3.5 m2, the maximum heat which can be absorbed is 3992 W for the highest solar intensity of 970 W/m2 at 12.00 and horizontal position of the solar collector. At this condition, the highest outlet temperature of water is 347.15 K with mass flow rate 0.02 kg/s and inlet temperature 298 K.

  12. Analysis of a combined power and refrigeration cycle by the exergy method

    Energy Technology Data Exchange (ETDEWEB)

    Vidal, A. [Posgrado en Ingenieria (Energia), sede CIE-UNAM, Privada Xochicalco s/n, col. Centro, 62580, Temixco, Morelos (Mexico)]. E-mail: avs@cie.unam.mx; Best, R. [Centro de Investigacion en Energia, CIE-UNAM, Privada Xochicalco s/n, col. Centro, 62580, Temixco, Morelos (Mexico); Rivero, R. [Instituto Mexicano del Petroleo, Grupo de Exergia, Eje Central Lazaro Cardenas No. 152, 07730, Mexico D.F. (Mexico); Facultad de Ingenieria, UNAM, Ciudad Universitaria, Mexico D.F. (Mexico); Cervantes, J. [Facultad de Ingenieria, UNAM, Ciudad Universitaria, Mexico D.F. (Mexico)

    2006-12-15

    The exergy analysis method was applied in order to evaluate the new combined cycle proposed by Goswami [Solar thermal technology: present status and ideas for the future. Energy Sources 1998;20:137-45], using Hasan-Goswami-Vijayaraghavan parameters. This new combined cycle was proposed to produce both power and cooling simultaneously with only one heat source and using ammonia-water mixture as the working fluid. The simulation of the cycle was carried out in the process simulator ASPEN Plus. The Redlich-Kwong-Soave equation of state was used to calculate the thermodynamic properties. The cycle was simulated as a reversible as well as an irreversible process to clearly show the effect of the irreversibilities in each component of the cycle. At the irreversible process two cases were considered, changing the environmental temperature. However, in order to know the performance of the new cycle at different conditions of operation, the second irreversible case was analyzed varying the rectification temperatures, the isentropic efficiency of the turbine and the return temperature of the chilled water. Exergy effectiveness values of {approx}53% and {approx}51% were obtained for the irreversible cycles; with heat input requirements at temperatures of 125 and 150 deg. C. Solar collectors or waste heat are suggested as heat sources to operate the cy0009c.

  13. Supersonic two-phase flow of CO{sub 2} through converging-diverging nozzles for the ejector refrigeration cycle

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Masafumi [Department of Mechanical and Structural System Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi City, Aichi 441-8580 (Japan); Berana, Menandro Serrano [Department of Mechanical and Structural System Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi City, Aichi 441-8580 (Japan); Department of Mechanical Engineering, University of the Philippines, Diliman, Quezon City 1101 (Philippines); Kishine, Akinori [Machine Tool Division, Murata Machinery, Ltd., 2 Nakajima, Hashizume, Inuyama City, Aichi 484-8502 (Japan)

    2009-09-15

    CO{sub 2} is environmentally friendly, safe and more suitable to ejector refrigeration cycle than to vapor compression cycle. Supersonic two-phase flow of CO{sub 2} in the diverging sections of rectangular converging-diverging nozzles was investigated. The divergence angles with significant variation of decompression were 0.076 , 0.153 , 0.306 and 0.612 . This paper presents experimental decompression phenomena which can be used in designing nozzles and an assessment of Isentropic Homogeneous Equilibrium (IHE). Inlet conditions around 6-9 MPa, 20-37 C were used to resemble ejector nozzles of coolers and heat pumps. For inlet temperature around 37 C, throat decompression boiling from the saturated liquid line, supersonic decompression and IHE solution were obtained for the two large divergence angles. For divergence angles larger than 0.306 , decompression curves for inlet temperature above 35 C approached IHE curves. For divergence angles smaller than 0.306 or for nozzles with inlet temperature below 35 C, IHE had no solution. (author)

  14. Experimental Investigation of a Three-Bed Adsorption Refrigeration Chiller Employing an Advanced Mass Recovery Cycle

    Directory of Open Access Journals (Sweden)

    Atsushi Akisawa

    2009-07-01

    Full Text Available The performance of an advanced three-bed adsorption chiller with a mass recovery cycle has been experimentally investigated in the present study. The temperature and pressure of various components of the chiller were monitored to observe the dynamic behaviour of the chiller. The performances in terms of the coefficient of performance (COP and specific cooling power (SCP were compared with a conventional single stage. The results show that the proposed cycle produces COP and SCP values superior to those of the conventional single stage cycle for heat source temperature below 75 °C.

  15. 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.

  16. 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

    Honeywell and the Oak Ridge National Laboratory (ORNL) is to develop a Life Cycle Climate Performance (LCCP) modeling tool for optimally designing HVAC&R equipment with lower life cycle greenhouse gas emissions, and the selection of alternative working fluids that reduce the greenhouse gas emissions of HVAC&R equipment. In addition, an experimental evaluation program is used to measure the coefficient of performance (COP) and refrigerating capacity of various refrigerant candidates, which have differing GWP values, in commercial refrigeration equipment. Through a cooperative effort between industry and government, alternative working fluids will be chosen based on maximum reduction in greenhouse gases at minimal cost impact to the consumer. This project will ultimately result in advancing the goals of reducing greenhouse gas emissions through the use of low GWP working fluids and technologies for HVAC&R and appliance equipment, resulting in cost-competitive products and systems.

  17. Properties and Cycle Performance of Refrigerant Blends Operating Near and Above the Refrigerant Critical Point, Task 2: Air Conditioner System Study

    Energy Technology Data Exchange (ETDEWEB)

    Piotr A. Domanski; W. Vance Payne

    2002-10-31

    The main goal of this project was to investigate and compare the performance of an R410A air conditioner to that of an R22 air conditioner, with specific interest in performance at high ambient temperatures at which the condenser of the R410A system may be operating above the refrigerant's critical point. Part 1 of this project consisted of conducting comprehensive measurements of thermophysical for refrigerant R125 and refrigerant blends R410A and R507A and developing new equation of state formulations and mixture models for predicting thermophysical properties of HFC refrigerant blends. Part 2 of this project conducted performance measurements of split-system, 3-ton R22 and R410A residential air conditioners in the 80 to 135 F (27.8 to 57.2 C) outdoor temperature range and development of a system performance model. The performance data was used in preparing a beta version of EVAP-COND, a windows-based simulation package for predicting performance of finned-tube evaporators and condensers. The modeling portion of this project also included the formulation of a model for an air-conditioner equipped with a thermal expansion valve (TXV). Capacity and energy efficiency ratio (EER) were measured and compared. The R22 system's performance was measured over the outdoor ambient temperature range of 80 to 135 F (27.8 to 57.2 C). The same test range was planned for the R410A system. However, the compressor's safety system cut off the compressor at the 135.0 F (57.2 C) test temperature. The highest measurement on this system was at 130.0 F (54.4 C). Subsequently, a custom-manufactured R410A compressor with a disabled safety system and a more powerful motor was installed and performance was measured at outdoor temperatures up to 155.0 F (68.3 C). Both systems had similar capacity and EER performance at 82.0 F (27.8 C). The capacity and EER degradation of both systems were nearly linearly dependent with rising ambient outdoor ambient test temperatures. The

  18. Studi Variasi Flowrate Refrigerant pada Sistem Organic Rankine Cycle dengan Fluida Kerja R-123

    Directory of Open Access Journals (Sweden)

    Aria Halim Pamungkas

    2013-09-01

    Full Text Available Saat ini kelangkaan sumber energi fosil telah menjadi isu utama di seluruh dunia. Hal tersebut memberikan dampak yang signifikan di setiap aspek kehidupan dan salah satunya adalah di bidang pembangkit listrik. Salah satu sistem pembangkit listrik yang tidak menggunakan energi fosil adalah Organic rankine cycle (ORC. Pada penelitian ini dilakukan dengan metode eksperimental pada suatu sistem Organic rankine cycle yang telah dibangun. Penelitian ini yang divariasikan adalah flowrate dari fluida kerja dalam hal ini R-123. Variasi flowrate yang digunakan yaitu 3-1 GPM (Galon per menit dengan penurunan 0,5 GPM setiap pengambilan data. Hasil yang didapatkan dari penelitian ini berupa grafik–grafik daya pada turbin, kondensor, pompa dan evaporator, efisiensi siklus dan back work ratio  fungsi flowrate fluida kerja. Efisiensi siklus tertinggi adalah 5,86% yang terjadi pada flowrate 3 GPM dan efisiensi siklus terendah adalah 4,32% yang terjadi pada flowrate 1 GPM.

  19. Magnetic Refrigeration and the Magnetocaloric Effect

    DEFF Research Database (Denmark)

    Petersen, Thomas Frank; Pryds, Nini; Smith, Anders

    2006-01-01

    Magnetic refrigeration at room temperature is an emerging technology for refrigeration, which promises low energy consumption and is environmentalle friendly. Magnetic refrigeration is based on the magnetocaloric effect, which manifests itself as a reversibel increase in temperature when magnetic...... material are plased in a magnetic field. This paper introduces and describes magnetic refrigeration cycles and the magnetocaloric effect, and shows how magnetic refrigeration can be an alternative to vapour-compression refrigeration,. A review of the Danish research on magnetic refrigeration at Risø...

  20. Study and control of the optimal generation temperature in NH{sub 3}-H{sub 2}O absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Seara, Jose; Vazquez, Manuel [Escuela Tecnica Superior de Ingenieros Industriales, Area de Maquinas y Motores Termicos, Vigo (Spain)

    2001-02-01

    This paper presents the results of a study on the optimal generator temperature (OGT) in single stage NH{sub 3}-H{sub 2}O Absorption Refrigeration Systems (AARS). It is well known that the generation temperature affects the AARS's Coefficient of Performance (COP) and that there is a temperature value, called optimal generation temperature, for which the COP is maximum. Therefore, to develop new control strategies designed to maintain the optimal temperature in the system generator, it is necessary to study the dependency of this temperature on thermal operating conditions and system design parameters. One such type of study has been carried out here by means of a parametric analysis, using a simple model implemented in a computer program. Based on the results obtained a novel control system that works on two separated control-loops has been designed. The proposed control system maintains a constant temperature in the space to refrigerate as well as the optimal temperature in the system generator. (Author)

  1. Absorptive capacity, technological innovation, and product life cycle: a system dynamics model

    National Research Council Canada - National Science Library

    Zou, Bo; Guo, Feng; Guo, Jinyu

    2016-01-01

    .... Based on interviews with 24 Chinese firms, this study develops a system-dynamics model that incorporates an important feedback loop among absorptive capacity, technological innovation, and product life cycle (PLC...

  2. 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 ...

  3. Calculation procedure to determine average mass transfer coefficients in packed columns from experimental data for ammonia-water absorption refrigeration systems

    Energy Technology Data Exchange (ETDEWEB)

    Sieres, Jaime; Fernandez-Seara, Jose [University of Vigo, Area de Maquinas y Motores Termicos, E.T.S. de Ingenieros Industriales, Vigo (Spain)

    2008-08-15

    The ammonia purification process is critical in ammonia-water absorption refrigeration systems. In this paper, a detailed and a simplified analytical model are presented to characterize the performance of the ammonia rectification process in packed columns. The detailed model is based on mass and energy balances and simultaneous heat and mass transfer equations. The simplified model is derived and compared with the detailed model. The range of applicability of the simplified model is determined. A calculation procedure based on the simplified model is developed to determine the volumetric mass transfer coefficients in the vapour phase from experimental data. Finally, the proposed model and other simple calculation methods found in the general literature are compared. (orig.)

  4. 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)

  5. Theoretical and Experimental Study on the Enhancement Effect of Mechanical Vibration on Absorption Refrigeration%机械振动对吸收式制冷强化作用的理论与试验研究

    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

    针对吸收式制冷机的传热传质过程,提出了一种通过振动来强化其过程的方法。搭建了相关的试验台,将一台吸收式制冷机组放置在一个电动振动台上,电动振动台的频率和振幅可调节,对吸收式制冷机组在振动情况下的运行情况进行了试验研究,探究振动对其传热传质的强化效果。%A new method of enhancing the heat and mass transfer process of absorption refrigerating machine by adding vibration into the system.Relevant test bench had been set up thus an absorption refrigerating unit was put on the top of the vibration table and the frequency and amplitude of the vibration table can be regulated to change the running conditions of the absorption refriger-ating unit to explore the effects of vibration on the heat and mass transfer process of absorption refrigerating machine.

  6. Experimental Study of Ambient Air Temperature Effects on The Performance of a General Vapor-Compression Refrigeration Cycle

    Directory of Open Access Journals (Sweden)

    Ayad T. Mustafa

    2013-05-01

    Full Text Available         In this work an experimental study for the vapor – compression refrigeration cycle has been performed under temperature range of  9.7-32°C. The effect of      varying temperature on heat exchangers pressures, cooling capacity, net power consumption, and coefficient of performance COP are studied .                                   The results indicated that condenser pressure, evaporator pressure, and power consumption increased with the increase of temperature. The data also indicated that cooling capacity increased as temperature increased until 15.6°C then after it decreased with further temperature increase. Also COP follow the same tread of cooling capacity.                                                                                                              

  7. 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.

  8. 渔船氨水吸收式制冷系统的建模和理论运行特性分析%Simulation and theoretical operation characteristics analysis of ammonia-water absorption refrigeration system for fishing boat

    Institute of Scientific and Technical Information of China (English)

    倪锦; 顾锦鸿; 沈建

    2012-01-01

    根据渔船节能减排的需求,设计了一种新型的渔船氨水吸收式制冷系统,利用渔船余热实现渔船的制冰、蓄冷和工作区域供冷,解决了渔船上鱼类的保鲜和冷藏,改善船上工作环境.建立了渔船氨水吸收式制冷的热力学模型和性能评价指标,在此基础上采用序贯模块法迭代求解,实现了渔船氨水吸收式制冷系统的仿真,同时进一步研究了不同操作条件下制冷系统的运行特性,最终获得了烟气温度、流量和三通阀开度等参数变化时各用户端功率的变化规律.该系统模型可指导渔船制冷系统的功率分配,为优化渔船制冷系统的运行参数、实现低碳渔船提供理论基础.%A new type of fishing boat ammonia-water absorption refrigeration system considering the characteristics of fishing boat was designed.It drove by exhaust gas from the fishing boat's engine,it could realize ice-making,cool storage and environment cooling,the fishing boat refrigeration system could not only serve for fish cold storage and fish fresh-keeping,but also serve for fishing boat's environment cooling.The thermodynamic mathematical model and evaluation index for fishing boat ammonia-water absorption refrigeration system were established,the sequential modular approach was applied to solving ammonia-water absorption refrigeration system,so the simulation of ammonia-water absorption refrigeration system for fishing boat was realized.The refrigeration system's operation characteristics under different gas parameters and different three-way valve's operating conditions were investigated,Results shown that the system's operation characteristics could not only give fishing boat refrigeration system's power assignment,but also lay theoretical foundation for fishing boat refrigeration system's operation optimization and low carbon emission fishing boat.

  9. 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.

  10. Thermodynamic Analysis on Sub-cooling Process in CO2 Trans-critical Refrigeration Cycle%二氧化碳跨临界制冷循环过冷却过程热力学分析

    Institute of Scientific and Technical Information of China (English)

    邓帅; 王如竹; 代彦军

    2013-01-01

    The feasibility of applying the sub-cooling technology to the CO2 trans-critical cycle was discussed, and the performance of new cycle was analyzed as well. Particularly, sub-cooling conversed from solar thermal energy was analyzed through simulation for possible applications. The calculation results show that cooling COP of the cycle reached to 4.00 and can be increased by 45.0%when temperature difference of sub-cooling is 5℃ in summer. While sub-cooling is realized by a solar-driven absorption refrigeration cycle and the driving temperature is 94℃, the assisted cooling capacity transformed from regenerative energy reached to 33%of the total cooling capacity. The difference in the sub-cooling process between conventional refrigerants subcritical cycle and CO2 trans-critical cycle was also discussed briefly.%本文探讨了过冷却技术应用于二氧化碳跨临界制冷循环的可行性,并对更新后的循环进行了性能分析,特别对太阳能应用于过冷却过程进行了模拟分析,最后通过现场实验对性能提升效果进行了验证。理论循环计算显示夏季5℃过冷可使循环COP达到4.00,制冷性能提升45%;当使用太阳能驱动的吸收式制冷循环产生过冷时,驱动温度为94℃时,可再生能源转化的辅助制冷量占总制冷量的比例可达33%。过冷热力过程在二氧化碳跨临界制冷循环中与在常规制冷剂亚临界制冷循环中有所不同,故本文对这种异同进行了适当的讨论。

  11. Performance characteristics of a magnetic Ericsson refrigeration cycle using Gd{sub x}Dy{sub 1−x} as the working substance

    Energy Technology Data Exchange (ETDEWEB)

    Diguet, Gildas, E-mail: diguet_gildas@yahoo.fr; Lin, Guoxing, E-mail: gxlin@xmu.edu.cn; Chen, Jincan, E-mail: jcchen@xmu.edu.cn

    2014-01-15

    Based on the experimental isothermal entropy change of the magnetic materials Gd{sub x}Dy{sub 1−x}, the thermodynamic performance of a regeneration Ericsson refrigeration cycle is evaluated and analyzed. The effects of non-perfect regeneration on the cyclic performance are highlighted. For a room temperature hot reservoir, the cooling quantity, non-perfect regeneration heat quantity, and net cooling quantity of the established regeneration Ericsson refrigeration cycle are calculated as a function of the cold reservoir temperature. Furthermore, for several typical compositions x of the Gd{sub x}Dy{sub 1−x} alloys, the values of the cooling quantity, non-perfect regeneration heat quantity, work input, net cooling quantity, and coefficient of performance (COP) are listed for given temperatures of the cold reservoir. The cyclic performance of the Gd{sub x}Dy{sub 1−x} alloys with different composition x is compared and some significant analyses are provided. - Highlights: • We examine the thermodynamics properties of the magnetocaloric alloys Gd{sub x}Dy{sub 1−x}. • We model a magnetic Ericsson cycle with regeneration process. • Calculations are based on experimental isothermal entropies change. • A cold reservoir temperature limit was found depending on ‘x’ composition value and operating conditions. • Lowest ‘x’ composition values have larger COP but lower net cooling quantities.

  12. 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.

  13. Integrating giant microwave absorption with magnetic refrigeration in one multifunctional intermetallic compound of LaFe(11.6)Si(1.4)C(0.2)H(1.7).

    Science.gov (United States)

    Song, Ning-Ning; Ke, Ya-Jiao; Yang, Hai-Tao; Zhang, Hu; Zhang, Xiang-Qun; Shen, Bao-Gen; Cheng, Zhao-Hua

    2013-01-01

    Both microwave absorption and magnetocaloric effect (MCE) are two essential performances of magnetic materials. We observe that LaFe(11.6)Si(1.4)C(0.2)H(1.7) intermetallic compound exhibits the advantages of both giant microwave absorption exceeding -42 dB and magnetic entropy change of -20 Jkg(-1)K(-1). The excellent electromagnetic wave absorption results from the large magnetic loss and dielectric loss as well as the efficient complementarity between relative permittivity and permeability. The giant MCE effect in this material provides an ideal technique for cooling the MAMs to avoid temperature increase and infrared radiation during microwave absorption. Our finding suggests that we can integrate the giant microwave absorption with magnetic refrigeration in one multifunctional material. This integration not only advances our understanding of the correlation between microwave absorption and MCE, but also can open a new avenue to exploit microwave devices and electromagnetic stealth.

  14. 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.

  15. 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。

  16. Thermodynamic equation of state approach for the choice of working fluids of absorption cooling cycles

    Science.gov (United States)

    Gomez, A. L.; Mansoori, G. A.

    1983-01-01

    A methodology is developed for the application of thermodynamic equations of state of fluids and fluid mixtures in evaluating working fluid combinations of absorption cooling cycles. Thermodynamic phase equilibrium formulation of this methodology is presented. In the application of this approach for the comparative study and choice of working fluids, the Redlich-Kwong equation of state is used for a number of possible working fluid combinations for solar absorption cooling cycles. It is demonstrated that when limited experimental data are at hand this approach could be a useful screening technique for potential working fluid combinations.

  17. 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.

  18. 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.

  19. 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.

  20. High Efficiency Refrigeration Process Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A refrigeration cycle is proposed for development which can reduce compressor work and increase cooling effect, by eliminating a portion of the irreversabilities...

  1. 新型双重热化学吸附制冷热力循环研究%Study on an Innovative Combined Double-Way Thermochemical Sorption Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    李廷贤; 王如竹; 陈恒; 王丽伟

    2011-01-01

    本文提出了一种全新的基于吸附-再吸附技术的双重热化学吸附制冷热力循环.实验研究表明该新型双重热化学吸附制冷热力循环用于制冷空调领域是完全可行的,在每次循环过程中仅从外界热源输入一次高温解吸热,就可以实现吸附制冷和再吸附制冷两次制冷过程;相对传统热化学再吸附制冷循环和吸附制冷循环,双重热化学吸附制冷热力循环可显著提高吸附制冷系统的工作性能,在相同制冷剂循环量下,双重热化学吸附制冷循环可将制冷系数COPi分别提高60%和167%.%In this paper, an innovative combined double-way thermochemical sorption refrigeration cycle based on adsorption and resorption processes is proposed. Experimental results showed that the presented combined double-way sorption cycle is feasible for refrigeration application, and two cold productions (adsorption refrigeration and resorption refrigeration) can be obtained during one cycle at the expense of only one heat input from an external heat source. In comparison with conventional thermochemical resorption cycle or adsorption cycle, the double-way sorption cycle has a distinct advantage of higher Coefficient of Performance (COP). At the same cycled mass of refrigerant, the ideal COP can be improved by 60% and 167% when compared with conventional resorption cycle and adsorption cycle, respectively.

  2. ExPerimental Research on Vibrating Effect for AbsorPtion Refrigeration%振动对于吸收式制冷影响的实验研究

    Institute of Scientific and Technical Information of China (English)

    申江; 董斌; Josephine LaU; 申子奇; 王建民

    2014-01-01

    利用已搭建的装有电动振动系统的溴化锂吸收式制冷实验台,对溴冷机各主要部件的性能进行实验分析。主要分析振动对于吸收式制冷过程中传热和制冷性能的影响。通过实验数据的处理和分析可以看出;在低频振动状态下,蒸发器﹑吸收器内的换热效果均优于静止的情形,表明低频振动有利于强化换热,同时增加了机组制冷量,提高了机组 COP 值。%Lithium bromide absorption refrigeration testing with an electric vibrating system was established.Making use of the testing, performance of major parts of LiBr absorption chiller is analyzed.The main purpose is to analyze the effect of vibration on the performance of heat transfer and cooling during absorption refrigeration.The results indicate that compared with static conditions, the heat transfer property of the absorber and the evaporator has a better performance under vibrating conditions.The vibration contributes to heat transfer enhancement, increases refrigerating capacity and improves the COP.

  3. 太阳能单效溴化锂吸收式制冷空调技术研究现状%Research Status of Solar Single-effect Lithium Bromide Absorption Refrigeration and Air Conditioning Technology

    Institute of Scientific and Technical Information of China (English)

    周兴法; 谢应明; 谢振兴

    2014-01-01

    In view of the solar single-effect lithium bromide absorption refrigeration and air conditioning technology , which is used mostly in solar refrigeration technology at present , the solar collectors that are available for solar refrigeration are introduced in detail,large amounts of the cases of experimental study and simulation analysis are enumerated ,and finally a novel solar refrige-ration system with bubble pump is presented .Because of its several advantages such as quiet , small volume, energy conserva-tion,and cooling heat recovery ,it is an important development direction of solar absorption refrigeration system in terms of minia-turization.%针对目前太阳能制冷技术中应用最多的太阳能单效溴化锂吸收式制冷空调技术,介绍各种可用于太阳能制冷空调的集热器,列举大量的太阳能单效溴化锂吸收式制冷空调系统的试验研究和模拟分析的案例,最后提出一个新型太阳能无泵溴化锂吸收式制冷空调系统。该系统具有运行安静、体积小、节能、可回收冷却热等优点,是太阳能吸收式制冷系统小型化的一个重要发展方向。

  4. Modeling and Analysis of Basic Chemical Adsorption Refrigeration Cycle%基本循环化学吸附式制冷建模与分析

    Institute of Scientific and Technical Information of China (English)

    冯玉坤; 杨晓; 马连湘

    2015-01-01

    在分析基本吸附制冷循环的基础上,建立了吸附制冷热力过程中的计算表达式。采用Matlab/Simulink模拟手段对氯化钙-氨制冷工况对制冷性能的影响进行了热力计算及分析。本文研究了不同解吸终了温度、蒸发温度、冷凝温度、吸附终了温度对系统COP的影响。经过分析发现,解吸终了温度在90℃附近时系统COP达到最大值,提高蒸发温度,降低冷凝温度和吸附终了温度有利于系统COP的提高。%Based on the analysis of the basic adsorption refrigeration cycle, the heat energy equation in the process of adsorption refrigeration is listed. The model of the CaCl2-NH3 refrigeration condition is based on the Matlab, which is calculated and analyzed for the influence of the cooling performance. In this text, it affects the COP of the system, at different desorption temperatures, evaporating temperatures, condensing temperatures, adsorption temperatures. Discover that the COP of the system, will have a maximum value when the desorption temperature around 90℃,and will be greater when raising the evaporation temperature, lower the condensation temperature and adsorption temperature.

  5. 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.

  6. Efficiency Calculations For a Magnetic Refrigerator Operating Between 2K and 10K

    Science.gov (United States)

    Helvensteijn, Ben P. M.; Kashani, A.; Kittel, P.; Sperans, Joel (Technical Monitor)

    1994-01-01

    An adiabatic demagnetization refrigerator (ADR) is being developed at NASA-Ames Research Center. The ADR will operate between 2 K and 10 K and will provide 50 mW of cooling at 2 K. The refrigerant in the ADR is Gadolinium Gallium Garnet (GGG). Absorption of heat at 2 K and heat rejection at 10 K in this fully static refrigerator is made possible by the incorporation of 2 K and 10 K heat switches. Physical layout and experimental results are presented in a parallel paper. The present paper discusses the thermal losses associated with components of the ADR as they occur in various parts of the refrigeration cycle. The results are summarized in terms of a prediction for the ADR efficiency.

  7. 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.

  8. Experimental evaluation of the inter-stage conditions of a two-stage refrigeration cycle using a compound compressor

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-03-15

    The aim of the present paper is to detail an analysis, based on experimental data, of the inter-stage working conditions of a two-stage vapour compression facility equipped with a compound compressor, which operates with the most usual inter-stage configurations (two-stage with direct liquid injection and two-stage with subcooler) in medium- and low-capacity commercial refrigeration applications. The experimental analysis is performed in an evaporating temperature range between -36 and -20 C, and in a condensing temperature range between 30 and 47 C, using one of the fluids most widely-used in Europe for low-temperature applications, the R-404a. The inter-stage working temperature/pressure obtained in the tests has been contrasted with the two usual criterion of the optimum working conditions definition: the arithmetical mean of the refrigerant condensing and evaporating temperatures and the criterion of equal pressure ratios in both stages. This paper presents the differences and affinities with the criterion and analyses the influence of the intermediate systems (direct liquid injection and subcooler) on the inter-stage operating conditions. (author)

  9. CO2跨临界喷射制冷循环计算分析%Calculation and analysis on transcritical ejector refrigeration cycle with CO2

    Institute of Scientific and Technical Information of China (English)

    王菲; 杨勇; 沈胜强

    2013-01-01

    The research on transcritical ejector refrigeration cycle with CO2 is rarely reported.In this study,a thermodynamic model for a transcritical ejector refrigeration cycle is established.The changes of ejector entrainment ratio,the cycle performance coefficient (COP) and effective performance coefficient (COPm) with cooler pressure,cooler outlet temperature,heater pressure,heater outlet temperature and evaporation temperature are presented.As the cooler pressure increases,the entrainment ratio of ejector decrease,the cycle COP and COPm first increase and then decrease,with optimum values at some cooler pressures.As the outlet temperature of cooler increases,both values of COP and COPm decrease.With the increase of heater pressure,heater outlet temperature and evaporation temperature,the ejector entrainment ratio,the cycle COP and COPm are improved,while the cycle COP decreases with the increase of heater outlet temperature.%目前还很少有关于CO2跨临界喷射式制冷循环的研究.本文对CO2跨临界喷射制冷循环建立了热力学模型,计算了在不同的冷却压力、冷却器出口温度、加热器压力、加热器出口温度及蒸发温度下,喷射器的喷射系数、跨临界喷射制冷循环性能系数(COP)和有效性能系数(COPm)的变化趋势.结果表明:随着冷却器压力的升高,喷射器的喷射系数减小,循环的COP和COPm值先增大后减小,在某个冷却压力下存在最优值;提高冷却器的出口温度,循环的COP和COPm值均降低;提高加热器压力、加热器出口温度及蒸发温度均能增大喷射器的喷射系数和循环的COPm值.

  10. Evaluation Analysis of the CO2 Emission and Absorption Life Cycle for Precast Concrete in Korea

    Directory of Open Access Journals (Sweden)

    Taehyoung Kim

    2016-07-01

    Full Text Available To comply with recent international trends and initiatives, and in order to help achieve sustainable development, Korea has established a greenhouse gas (GHG emission reduction target of 37% (851 million tons of the business as usual (BAU rate by 2030. Regarding environmentally-oriented standards such as the IGCC (International Green Construction Code, there are also rising demands for the assessment on CO2 emissions during the life cycle in accordance with ISO (International Standardization Organization’s Standard 14040. At present, precast concrete (PC engineering-related studies primarily cover structural and construction aspects, including improvement of structural performance in the joint, introduction of pre-stressed concrete and development of half PC. In the manufacture of PC, steam curing is mostly used for the early-strength development of concrete. In steam curing, a large amount of CO2 is produced, causing an environmental problem. Therefore, this study proposes a method to assess CO2 emissions (including absorption throughout the PC life cycle by using a life cycle assessment (LCA method. Using the proposed assessment method, CO2 emissions during the life cycle of a precast concrete girder (PCG were assessed. In addition, CO2 absorption was assessed against a PCG using conventional carbonation and CO2 absorption-related models. As a result, the CO2 emissions throughout the life cycle of the PCG were 1365.6 (kg-CO2/1 PCG. The CO2 emissions during the production of raw materials among the CO2 emissions throughout the life cycle of the PCG were 1390 (kg-CO2/1 PCG, accounting for a high portion to total CO2 emissions (nearly 90%. In contrast, the transportation and manufacture stages were 1% and 10%, respectively, having little effect on total CO2 emissions. Among the use of the PCG, CO2 absorption was mostly decided by the CO2 diffusion coefficient and the amount of CO2 absorption by cement paste. The CO2 absorption by carbonation

  11. Absorptive capacity, technological innovation, and product life cycle: a system dynamics model.

    Science.gov (United States)

    Zou, Bo; Guo, Feng; Guo, Jinyu

    2016-01-01

    While past research has recognized the importance of the dynamic nature of absorptive capacity, there is limited knowledge on how to generate a fair and comprehensive analytical framework. Based on interviews with 24 Chinese firms, this study develops a system-dynamics model that incorporates an important feedback loop among absorptive capacity, technological innovation, and product life cycle (PLC). The simulation results reveal that (1) PLC affects the dynamic process of absorptive capacity; (2) the absorptive capacity of a firm peaks in the growth stage of PLC, and (3) the market demand at different PLC stages is the main driving force in firms' technological innovations. This study also explores a sensitivity simulation using the variables of (1) time spent in founding an external knowledge network, (2) research and development period, and (3) knowledge diversity. The sensitivity simulation results show that the changes of these three variables have a greater impact on absorptive capacity and technological innovation during growth and maturity stages than in the introduction and declining stages of PLC. We provide suggestions on how firms can adjust management policies to improve their absorptive capacity and technological innovation performance during different PLC stages.

  12. Combined vapor compression/absorption heat pump cycles for engine-driven heat pumps

    Science.gov (United States)

    Radermacher, Reinhard; Herold, Keith E.; Howe, Lawrence A.

    1988-12-01

    The performance of three combined absorption/vapor compression cycles for gas-fired internal combustion engine driven heat pumps was theoretically assessed. Two cycles were selected for the preliminary design of breadboard systems using only off-the-shelf components. The first cycle, based on the working pair ammonia/water, is termed the simple-cycle. The second cycle, based on the working pair lithium-bromide/water, is termed the compressor enhanced double-effect chiller. Both cycles are found to be technically feasible. The coefficient of performance and the capacity are increased by up to 21 percent for cooling in the first case (compressor efficiency of 0.7) and by up to 14 percent in the second (compressor efficiency of 0.5). Both were compared against the engine drive R22 vapor compression heat pump. The performance of actual machinery for both cycles is, in the current design, hampered by the fact that the desired oil-free compressors have poor isentropic efficiencies. Oil lubricated compressors together with very effective oil separators would improve the performance of the combined LiBr/water cycle to 23 percent.

  13. Sistema de refrigeración solar por absorción para la comunidad de Kumay en Ecuador; Solar absorption refrigeration system for Kumay community in Ecuador

    Directory of Open Access Journals (Sweden)

    José Antonio Romero Paguay

    2015-04-01

    Full Text Available En el Ecuador existen muchas zonas aisladas, no electrificadas aún, especialmente en la provincia de Pastaza, en este artículo se presenta un sistema de refrigeración por absorción solar  como una alternativa para la climatización de un consultorio médico en la Comunidad de Kumay. Se realiza el cálculo de la estimación de carga térmica en el consultorio médico empleando el software Carrier E20, el cual arroja una necesidad de enfriamiento de 10 kW o 2,84 toneladas de refrigeración (TR. El sistema de refrigeración por absorción con energía solar propuesto está formado por una máquina de absorción, simple efecto de la marca ClimateWell 10, con 10 kW de potencia de enfriamiento que utiliza como absorbente el par cloruro de litio y agua, requiriéndose un área de captación de energía solar de 30 m2 que será entregada con diez colectores de tubos alvacío marca Thermomax, Modelo Solamax 30. In Ecuador there are many non-electrified remote areas, especially in the province of Pastaza, in this article a solar absorption cooling system is presented as an alternative for the air conditioning of a doctor's office (medical clinic in Community Kumay. The calculation of the estimated thermal load on the doctor's office is done using the software Carrier E20, which throws a necessity of cooling of 10 kW or 2,84 tons of refrigeration. The solar cooling system consist in an absorption machine of single effect, ClimateWell 10, with 10 kW of cooling power that uses as absorbent the lithium chloride and water pair, this system  required an area of reception of solar energy of 30 m2 that will be given with 10 vacuum tube collectors Thermomax, Model Solamax 30.

  14. Performance Analysis of a Modified Novel Absorption-compression Hybrid GAX Cycle%一种改进的吸收-压缩混合GAX制冷循环理论性能分析

    Institute of Scientific and Technical Information of China (English)

    陈光明; 石玉琦; 洪大良

    2016-01-01

    吸收式制冷是热能利用的重要形式之一,氨吸收式制冷中的 GAX(发生–吸收热交换器)循环具有相对较高的效率,吸收–压缩耦合的混合GAX循环可以进一步提高GAX循环效率。为了应对GAX循环中GAXA(发生–吸收热交换器吸收器)和GAXG(发生–吸收热交换器发生器)热量匹配问题,提出了一个改进的吸收–压缩混合 GAX 循环。研究了蒸发温度、冷凝温度、放气范围和换热温差对新循环和基础GAX 循环的影响。新循环较基础 GAX 循环性能在大部分工况下有显著提升,COP 提高可达30%以上,尽管如此,模拟现实新循环仍具有一定的适用范围。%Absorption refrigeration is one of the most important method on utilizing thermal energy. GAX (generator-absorber heat exchanger) cycle has a relatively high performance in ammonia absorption refrigeration family. Absorption-compression coupled hybrid GAX cycle can further improve the efficiency of GAX cycle. In order to solve the heat marching problem of GAXA (generator-absorber heat exchanger absorber) and GAXG (generator-absorber heat exchanger generator) heat exchangers, a modified novel absorption-compression hybrid GAX cycle was proposed. Effect of evaporation temperature, cooling temperature, degassing range and approach temperature on performance of new cycle and basic GAX cycle was studied. Performance of new cycle has a significant improvement, compared to basic GAX cycle, which 30% improvement can be achieved. Nevertheless, the scope of application of the new cycle varies with working conditions.

  15. Simulated performance of biomass gasification based combined power and refrigeration plant for community scale application

    Science.gov (United States)

    Chattopadhyay, S.; Mondal, P.; Ghosh, S.

    2016-07-01

    Thermal performance analysis and sizing of a biomass gasification based combined power and refrigeration plant (CPR) is reported in this study. The plant is capable of producing 100 kWe of electrical output while simultaneously producing a refrigeration effect, varying from 28-68 ton of refrigeration (TR). The topping gas turbine cycle is an indirectly heated all-air cycle. A combustor heat exchanger duplex (CHX) unit burns producer gas and transfer heat to air. This arrangement avoids complex gas cleaning requirements for the biomass-derived producer gas. The exhaust air of the topping GT is utilized to run a bottoming ammonia absorption refrigeration (AAR) cycle via a heat recovery steam generator (HRSG), steam produced in the HRSG supplying heat to the generator of the refrigeration cycle. Effects of major operating parameters like topping cycle pressure ratio (rp) and turbine inlet temperature (TIT) on the energetic performance of the plant are studied. Energetic performance of the plant is evaluated via energy efficiency, required biomass consumption and fuel energy savings ratio (FESR). The FESR calculation method is significant for indicating the savings in fuel of a combined power and process heat plant instead of separate plants for power and process heat. The study reveals that, topping cycle attains maximum power efficiency of 30%in pressure ratio range of 8-10. Up to a certain value of pressure ratio the required air flow rate through the GT unit decreases with increase in pressure ratio and then increases with further increase in pressure ratio. The capacity of refrigeration of the AAR unit initially decreases up to a certain value of topping GT cycle pressure ratio and then increases with further increase in pressure ratio. The FESR is found to be maximized at a pressure ratio of 9 (when TIT=1100°C), the maximum value being 53%. The FESR is higher for higher TIT. The heat exchanger sizing is also influenced by the topping cycle pressure ratio and GT-TIT.

  16. Improvement of the COP of the LiBr-Water Double-Effect Absorption Cycles

    Science.gov (United States)

    Shitara, Atsushi

    Prevention of the global warming has called for a great necessity for energy saving. This applies to the improvement of the COP of absorption chiller-heaters. We started the development of the high efficiency gas-fired double-effect absorption chiller-heater using LiBr-H2O to achieve target performance in short or middle term. To maintain marketability, the volume of the high efficiency machine has been set below the equal to the conventional machine. The absorption cycle technology for improving the COP and the element technology for downsizing the machine is necessary in this development. In this study, the former is investigated. In this report, first of all the target performance has been set at cooling COP of 1.35(on HHV), which is 0.35 higher than the COP of 1.0 for conventional machines in the market. This COP of 1.35 is practically close to the maximum limit achievable by double-effect absorption chiller-heater. Next, the design condition of each element to achieve the target performance and the effect of each mean to improve the COP are investigated. Moreover, as a result of comparing the various flows(series, parallel, reverse)to which the each mean is applied, it has been found the optimum cycle is the parallel flow.

  17. Performance Analysis of CO2 Transcritical Compression Cycle and Freon Refrigeration Cycle%CO2跨临界循环和氟利昂制冷剂循环性能分析

    Institute of Scientific and Technical Information of China (English)

    曾宪阳; 王洪利; 马一太

    2011-01-01

    Based on refrigerants R134a, R290 and CO2, the performance comparison of three kinds of single stage compression cycle and two stage cycle were employed.The results shows that the performances COP of all cycles are gradually increased with the evaporation temperature and compressor efficiency increasing, and the single stage CO2 transcritical cycle has an optimal discharge pressure.Replace the throttle with an expander can significantly improve the system coefficient of performance of CO2 transcritical cycle.The low stage compressor efficiency has an important effect on the performance of two stage compression cycle than the high stage compressor efficiency and the CO2 transcritical cycle has a higher optimal intermediate pressure than other cycles.Some fundamental data were obtained for improving cycle performance and developing the CO2 refrigeration air-conditioning and heat pump water heater products.%本文以R134a、R290和CO2制冷剂为研究对象,分别对三种单、双级循环的性能进行对比.结果表明,随蒸发温度增加、压缩机效率升高和冷凝器出口温度降低,所有循环性能均提高,单级CO2循环存在最优排气压力;用膨胀机代替节流阀可以显著提高CO2跨临界循环COP;低压级压缩机的效率比高压级压缩机对系统性能影响明显.双级循环中,CO2循环最优中间压力远高于其它两种循环.本研究为高效、节能的空调和热泵产品开发提供基础资料.

  18. 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.

  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. 一种新型自复叠制冷循环特性研究%Characteristics of a Novel Autocascade Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    王林; 谈莹莹; 梁坤峰; 崔晓龙

    2012-01-01

    The novel autocascade refrigeration cycle (ARC) is developed. The setup of the ejector in the outlet of the liquid flowing from the vapor-liquid separator effectively recovers the throttle loss which was caused by the throttle valve, increases the suction pressure of the low boiling point composition at the inlet of the compressor and achieves lower refrigeration temperature. Based on the thermodynamic models on components, the influences of condensing temperature, composition ratio of mixtures and compression ratio of the compressor on the characteristics of the novel ARC is analyzed. The results indicate that refrigeration temperature obtained from the novel ARC is 10-20℃ lower than that from the traditonal ARC, while COP of them is almost the same.%提出一种新型自复叠制冷循环,通过设置喷射器,利用高压高沸点液态制冷剂引射低压低沸点气态制冷剂,充分回收高沸点组分的节流损失,提高压缩机吸气口处低沸点组分的吸气压力并获取更低制冷温度。建立了组成系统部件热力学数学模型,分析了冷凝温度、混合工质配比和压缩比等参数对传统自复叠制冷循环和新型自复叠制冷循环的工作特性影响。研究表明,新型自复叠制冷循环制冷效率与传统自复叠制冷循环相当,但前者所获得制冷温度比后者所获得制冷温度可降低约10~20℃

  1. A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides.

    Science.gov (United States)

    Powell, J R; Salzano, F J; Yu, W S; Milau, J S

    1976-07-23

    A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output.

  2. 两次节流循环在氨制冷系统的效率分析%Efficiency analysis on the cycle with flash intercooler in ammonia refrigeration system

    Institute of Scientific and Technical Information of China (English)

    张建一; 陈海洋

    2012-01-01

    his paper analyzed the two - stage compression refrigeration cycle with different intercoolers. The refrigeration coefficients of cycles with shell - and - coil intercooler and flash intercooler were calculated based on a case of cold store. The results show that theoretical refrigeration coefficient.increased by 1.3% and the refrigeration coefficient for the case increased by 0. 7% -0.8% when shell - and - coil intercooler was replaced by Dash intercooler in two - stage compression cycle. The theoretical power consumption of refrigeration cycle with flash intercooler will decrease 5kW than that with shell - and - coil intercooler under full capacity. The initial investment cost will also reduce if flash intercooler is adopted in two - stage compression system.%文中分析不同节流方式下的两级压缩制冷循环.基于冷库实例,计算出了制冷循环在一次节流和二次节流方式下的制冷系数.结果显示,使用两次节流制冷循环,理论制冷系数提高了1.3%,冷库实例制冷系数提高了0.7%-0.8%.两次节流制冷系统在满负荷下运行时,压缩机消耗的理论功率比一次节流下降5kW.使用两次节流方式的制冷系统,在初投资费用上也有所降低.

  3. Design and Optimization on Simulation System of Mine CO2 Open Loop Cycle Refrigeration%矿用CO2开放式制冷仿真系统设计与优化

    Institute of Scientific and Technical Information of China (English)

    曹利波

    2013-01-01

    According to the importance of the CO2 open loop cycle refrigeration applied to the rescue cabin, the refuge chamber and other limited airtight space, the FLOWMASTER simulation software of the thermal fluid system was applied to design the simulation system of the CO2 open loop cycle refrigeration applied to a limited airtight space. Under the conditions to meet the designed refrigeration value and the pressure drop and temperature drop at the inlet and outlet of the pneumatic blower, the tube length of the evaporator was optimized and the optimum length of the evaporator was obtained. Meanwhile the refrigeration system features and the different refrigeration value under the non designed performances were checked.The test certification was conducted on the refrigeration simulation system.The simulated value and the test value were well fitted and the simulation accuracy and precision of the system were verified.%针对CO2开放式制冷在避难硐室、救生舱等有限密闭空间中应用的重要性,利用FLOWMASTER热流体计算仿真软件,设计了一种用于有限密闭空间的CO2开放式制冷仿真系统,在满足设计制冷量和气动风机进出口压降、温降的条件下,对蒸发器管长进行优化,获得了最佳蒸发器长度,同时对非设计工况下的制冷系统特性及不同制冷量进行校核,并对该制冷仿真系统进行了试验验证,仿真值与试验值吻合良好,验证了系统仿真的准确性和精确性.

  4. Thermodynamic analysis of transcritical CO2 refrigeration cycle with different expansion device%采用不同膨胀机构的跨临界CO2循环性能分析

    Institute of Scientific and Technical Information of China (English)

    马娟丽; 刘昌海; 侯予

    2012-01-01

    运用热力学第一定律和第二定律对跨临界CO2基本循环、膨胀机循环、喷射器循环和涡流管循环进行了分析,计算了各循环各个部件的(火用)损失,比较了各循环性能系数和总(火用)损失.计算结果表明,采用膨胀机、喷射器和涡流管等膨胀设备代替基本循环中的节流阀后,由于这些改进膨胀设备的(火用)损失小于基本循环节流阀的(火用)损失,同时改进循环中压缩机的(火用)损失小于基本循环的压缩机(火用)损失,从而减小了循环总(火用)损失,提高了循环的COP.膨胀机循环的COP远大于其它跨临界CO2循环,其次为喷射器循环和涡流管循环.%A comparative study on transcritical carbon dioxide refrigeration cycle respectively with throttling valve,expander,ejector and vortex tube was performed by the first and second laws of thermodynamics in theory. And these cycles' COP and exergy losses were investigated. It is found that the exergy loss of other expansion devices is less than the exergy loss of throttling valve. The exergy loss of compressor in transcritical carbon dioxide refrigeration cycle with other expansion devices is less than the exergy loss of compressor in transcritical carbon dioxide refrigeration cycle with throttling valve. Thus the total exergy loss of these cycles with other expansion devices is less than the total exergy loss of cycle with throttling valve, and the COP of these cycles with other expansion devices is higher than the COP of cycle with throttling valve. The COP of transcritical carbon dioxide refrigeration cycle with expander is much higher than that of other cycles, then transcritical carbon dioxide refrigeration cycle with ejector and with vortex tube.

  5. 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.

  6. Analysis on CO2 Refrigeration Cycle with High Pressure Gas Vortex Expansion for Low Temperature%高压气体涡流膨胀的CO2低温制冷循环分析

    Institute of Scientific and Technical Information of China (English)

    赵家华; 宁静红

    2016-01-01

    通过设计高压气体涡流膨胀的CO2低温制冷循环,对其进行热力性能分析,并与两级节流中间完全冷却的CO2低温制冷循环的性能进行对比,得出高压气体涡流膨胀的CO2低温制冷循环存在获得最大性能系数的最优的高压压力。提高蒸发温度与中间压力,增大冷气流质量比,减少进入蒸发器的冷气流质量比,降低气体冷却器出口温度,均可提高高压气体涡流膨胀的CO2低温制冷循环的性能系数。在冷气流的质量比为0.6,冷气流进入蒸发器的质量比为0.2时,高压气体涡流膨胀的CO2低温制冷循环的最佳的性能系数较两级节流中间完全冷却的CO2低温制冷循环最佳的性能系数提高36.4%。随着气体冷却器出口温度的升高,高压气体涡流膨胀的CO2低温制冷循环的性能系数较两级节流中间完全冷却的CO2低温制冷循环的性能系数降低的幅度小。%The CO2 refrigeration cycle with high pressure gas vortex expansion for low temperature is designed. The thermal performances of this CO2 refrigeration cycle with high pressure gas vortex expansion for low temperature are analyzed and compared with that of the CO2 low temperature refrigeration cycle of two-stage throttle and complete cooling in middle. The following conclusions are obtained. The CO2 refrigeration cycle with high pressure gas vortex expansion for low temperature has the maximum coefficient of performance ( COP) at the optimal high pressure. The coefficient of performances of the CO2 refrigeration cycle with high pressure gas vortex expansion for low temperature can be improved by increasing the evaporation temperature, the middle pressure and the mass ratio of cold gas, by reducing the mass ratio of cold gas into evaporator, as well as by decreasing the temperature of gas-cooler out-let. At the mass ratio of cold gas is 0. 6 and the mass ratio of cold gas into evaporator is 0. 2, the maximum coeffi-cient of performance of

  7. 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.

  8. 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.

  9. Cogeneration with gas turbine associated to the absorption refrigeration system: a computer program for exergy economics analysis; Cogeracao com turbina a gas associada ao sistema de refrigeracao por absorcao: um programa computacional para analise exergoeconomica

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Julio Santana [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Matematica] E-mail: santana@feg.unesp.br; Silveira, Jose Luz; Balestieri, Jose Antonio Perrella [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Energia

    2000-07-01

    This paper presents the development of a computer program for exergy and economic analysis of cogeneration systems applying gas turbine associated to the absorption refrigeration system. The computer program selects gas turbine systems viewing the operation under thermal parity through a data base composed by gas turbines commercially available in the market, under the ISO (International Standard Organization). The computer program corrects the system performance parameters selected for the installation local conditions. The exergy and economic analysis are made based on the lowest exergy manufacturing cost where the best system is considered. A case study of the computer program application is presented.

  10. Optimum operating regimes of common paramagnetic refrigerants

    CERN Document Server

    Wikus, P; Figueroa-Feliciano, E

    2011-01-01

    Adiabatic Demagnetization Refrigerators (ADRs) are commonly used in cryogenic laboratories to achieve subkelvin temperatures. ADRs are also the technology of choice for several space borne instruments which make use of cryogenic microcalorimeters or bolometers {[}1-4]. For these applications, refrigerants with high ratios of cooling capacity to volume, or cooling capacity to mass are usually required. In this manuscript, two charts for the simple selection of the most suitable of several common refrigerants (CAA, CMN, CPA, DGG, FAA, GGG, GLF and MAS) are presented. These graphs are valid for single stage cycles. The selection of the refrigerants is uniquely dependent on the starting conditions of the refrigeration cycle (temperature and magnetic field density) and the desired final temperature. Only thermodynamic properties of the refrigerants have been taken into account, and other important factors such as availability and manufacturability have not been considered. (C) 2011 Elsevier Ltd. All rights reserve...

  11. 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…

  12. A Novel Absorption Cycle for Combined Water Heating, Dehumidification, and Evaporative Cooling

    Energy Technology Data Exchange (ETDEWEB)

    CHUGH, Devesh [University of Florida, Gainesville; Gluesenkamp, Kyle R [ORNL; Abdelaziz, Omar [ORNL; Moghaddam, Saeed [University of Florida, Gainesville

    2014-01-01

    In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser. The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the

  13. 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.

  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 plants using carbon dioxide as refrigerant: measuring and modelling the solubility and diffusion of carbon dioxide in polymers used as sealing materials

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Kristensen, Jakob

    2010-01-01

    Because of increased environmental pressure, there is currently a movement away from more traditional refrigerants such as HCFC's toward refrigerants with lower global warming potential such as carbon dioxide (CO2). However, the use of CO2 as a refrigerant requires a refrigeration cycle...

  16. Performance characteristics of a direct liquid feeding ejector expansion refrigeration cycle%一种喷射器膨胀直接供液制冷循环及性能分析

    Institute of Scientific and Technical Information of China (English)

    谢令; 陈光明

    2015-01-01

    很多环保制冷剂如(R1234ze(E))具有蒸发压力低的特点,影响了其制冷性能。提出了将两相喷射器作为膨胀部件,将汽液分离后的纯液体供给蒸发器的直接供液式喷射器膨胀制冷循环(EERC)。以汽车空调系统为例,研究了循环COP与单位容积制冷量,结果表明采用R1234ze(E)的EERC循环相对于采用R134a的传统循环(TRC)COP提升在22%以上,并且容积制冷量也得到大幅提升,与采用R134 a的容积制冷量的差距从33%左右减小到了6%—12%;在高冷凝温度和低蒸发温度工况下,性能改善更加明显。直接供液式EERC无论是直接用来替代现有制冷循环,还是用在环保制冷剂特别是低压环保制冷剂替代传统制冷剂的场合都是一个很好的选择。%Performance of many environmentally friendly refrigerants (eg .R1234ze(E)) in refrigera-tion cycle is greatly affectedbyits low evaporating pressure .A new cycle called direct-liquid-feeding ejector expansion refrigeration cycle ( EERC) was proposed , in which a two-phase ejector works as the only expan-sion device and totallyliquid refrigerant rather than two phase one was fed to the evaporator .Taking automo-tive air-conditioner for example, the COP improvement of the EERC using R1234ze(E) as refrigerant over the traditional cycle(TRC) using R134a as refrigerant can be obtained by more than 22%at giving condi-tions.Besides, volumetric cooling capacity gap between them can be obviously reduced from about 33%to 6%-12%.According to the result , the performance will be much better in the cases of higher condensing temperature and lower evaporating temperature .It is concluded that the direct-liquid-feeding ejector expan-sion refrigeration cycle could be a good choice when using environmentally friendly refrigerants especially with lower evaporatingpressure ones toreplace traditional refrigerants .

  17. In vitro developmental competence of pig nuclear transferred embryos: effects of GFP transfection, refrigeration, cell cycle synchronization and shapes of donor cells.

    Science.gov (United States)

    Zhang, Yun-Hai; Pan, Deng-Ke; Sun, Xiu-Zhu; Sun, Guo-Jie; Liu, Xiao-Hui; Wang, Xiao-Bo; Tian, Xing-Hua; Li, Yan; Dai, Yun-Ping; Li, Ning

    2006-08-01

    The present study was designed to evaluate the feasibility of producing pig transgenic blastocysts expressing enhanced green fluorescent protein (GFP) and to examine the effects of shape and preparation methods of donor cells on in vitro developmental ability of pig nuclear transferred embryos (NTEs). In experiment 1, the effect of GFP transfection on development of pig NTEs was evaluated. The cleavage and blastocyst rates showed no significant difference between NTEs derived from transfected and non-transfected donors. In experiment 2, the effect of different nuclear donor preparation methods on in vitro development of NTEs was examined. The cleavage rate showed no statistically significant differences among three preparation methods. The blastocyst rates of donor cells treated once at -4 degrees C and those of freshly digested cells were similar to each other (26.3% vs 17.9%). The lowest blastocyst rates (5.88%) were observed when cells cryopreserved at -196 degrees C were used as donors. In experiment 3, the effect of different cell cycle synchronization methods on the in vitro development potential of pig NTEs was evaluated. The cleavage rate of NTEs derived from cycling cells was much better than that of NTEs derived from serum-starved cells (64.4% vs 50.5%, p refrigerated pig GFP-transfected cells could be used as donors in nuclear transfer and these NTEs could be effectively developed to blastocyst stage; (ii) serum starvation of GFP-transfected cells is not required for preimplantation development of pig NTEs; and (iii) a rough surface of GFP-transfected donor cells affects fusion rate negatively but has no influence on the cleavage rate or blastocyst rate of pig NTEs.

  18. 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 ...

  19. 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.

  20. Modeling of ammonia absorption chillers integration in energy systems of process plants

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.C.; Castells, F. [Universitat Rovira i Virgili, Tarragona (Spain). Dept. d' Enginyeria Quimica; Miquel, J. [Universitat Politecnica de Catalunya (Spain). Dept. de Mecanica de Fluids

    1999-12-01

    A mathematical programming approach is proposed to study the integration of absorption chillers in combined heat and power plants. The aim of this work is to determine the economic viability of the introduction of ammonia absorption chillers in energy systems instead of using the more conventional compression cycles. This procedure selects the best refrigeration alternative taking into account both absorption and compression cycles. To select the most suitable refrigeration cycle for a given refrigeration load, it is not only necessary to model the performance of each cycle, but also to take into account the interactions between the energy system and the considered cycles, optimizing the performance of the global plant. This approach has been implemented in the computer program XV, and tested in an energy plant in the petrochemical complex of Tarragona (Catalunya, Spain). The refrigeration demands to be met are at 0 and -20{sup o}C. The results highlighted the benefit obtained with the simultaneous presence of ammonia absorption cycles and a cogeneration based energy plant. (author)

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

    OpenAIRE

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

    2014-01-01

    The development in the field of refrigeration and air conditioning systems driven by absorption cycles acquired a considerable importance recently. For commercial absorption chillers, an essential challenge for creating chiller model certainly is the shortage of components technical specifications. These kinds of specifications are usually proprietary for chillers producers. In this paper, a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equa...

  2. Coefficient of Performance Optimization of Single-Effect Lithium-Bromide Absorption Cycle Heat Pumps

    DEFF Research Database (Denmark)

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

    2015-01-01

    In this paper, we investigate the coefficient of performance (COP) of a LiBr absorption cycle heat pump under different operating conditions. The investigation is carried out using a dynamical model fitted against data recorded from an actual heat pump used for district heating in S......⊘nderborg, Denmark. Since the model is too complex to study analytically, we vary different input variables within the permissible operating range of the heat pump and evaluate COP at the resulting steady-state operating points. It is found that the best set-point for each individual input is located at an extreme......-state operation of the heat pump, while avoiding crystallization issues....

  3. Exergetic sustainability evaluation of irreversible Carnot refrigerator

    Science.gov (United States)

    Açıkkalp, Emin

    2015-10-01

    Purpose of this paper is to assess irreversible refrigeration cycle by using exergetic sustainability index. In literature, there is no application of exergetic sustainability index for the refrigerators and, indeed, this index has not been derived for refrigerators. In this study, exergetic sustainability indicator is presented for the refrigeration cycle and its relationships with other thermodynamics parameters including COP, exergy efficiency, cooling load, exergy destruction, ecological function and work input are investigated. Calculations are conducted for endoreversible and reversible cycles and then results obtained from the ecological function are compared. It is found that exergy efficiency, exergetic sustainable index reduce 47.595% and 59.689% and rising at the COP is 99.888% is obtained for endoreversible cycle. Similarly, exergy efficiency and exergetic sustainability index reduce 90.163% and 93.711% and rising of the COP is equal to 99.362%.

  4. 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%。

  5. 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.

  6. TFE-TEGDME-He扩散-吸收式制冷系统实验研究%Experimental study on a diffusion absorption refrigeration system working with TFE-TEGDME-He

    Institute of Scientific and Technical Information of China (English)

    孟凡基; 龙臻; 李华山; 卜宪标; 马伟斌

    2014-01-01

    An experimental study on a water-cooled diffusion-absorption refrigeration (DAR) machine working with TFE (2,2,2-Trifluoroethanol) as refrigerant,TEGDME (Tetraethylene Glycol Dimethyl Ether) as absorber and helium as the auxiliary inert gas was presented.It was found that when the heating temperature reaches 112 ~ 135 ℃,the averaged cooling capacity is about 0.32kW with a maximum value of 0.58kW.The actual heat transfer coefficient of each heat exchanger component is obtained,which is very helpful for further development of the DAR system with kW-level cooling capacity.%建立了一套以TFE(三氟乙醇)为制冷剂,TEGDME(二甲醚四甘醇)为吸收剂,He(氦气)为压力平衡剂的水冷式扩散-吸收制冷系统,并进行实验研究.结果表明,当热水温度达到112~135℃时,机组可正常制冷,平均制冷功率约0.32kW,最大达0.58kW;同时获取了各换热器的实际传热系数,为kW级扩散-吸收式制冷机组的设计提供理论基础.

  7. 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…

  8. 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

  9. U.S. Residential Miscellaneous Refrigeration Products: Results from Amazon Mechanical Turk Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Greenblatt, Jeffery B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Young, Scott J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Hung-Chia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Long, Timothy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beraki, Bereket [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Sarah K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pratt, Stacy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Desroches, Louis-Benoit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-04-01

    Amazon Mechanical Turk was used, for the first time, to collect statistically representative survey data from U.S. households on the presence, number, type and usage of refrigerators, freezers, and various “miscellaneous” refrigeration products (wine/beverage coolers, residential icemakers and non-vapor compression refrigerators and freezers), along with household and demographic information. Such products have been poorly studied to date, with almost no information available about shipments, stocks, capacities, energy use, etc. A total of 9,820 clean survey responses were obtained from four distinct surveys deployed in 2012. General refrigeration product survey responses were weighted to demographics in the U.S. Energy Information Administration’s Residential Energy Consumption Survey 2009 dataset. Miscellaneous refrigeration product survey responses were weighted according to demographics of product ownership found in the general refrigeration product surveys. Model number matching for a portion of miscellaneous refrigeration product responses allowed validation of refrigeration product characteristics, which enabled more accurate estimates of the penetrations of these products in U.S. households. We estimated that there were 12.3±1.0 million wine/beverage coolers, 5.5(–3.5,+3.2) million residential icemakers and 2.9(–2.5,+4.5) million non-vapor compression refrigerators in U.S. households in 2012. (All numerical results are expressed with ranges indicating the 95% confidence interval.) No evidence was found for the existence of non-vapor compression freezers. Moreover, we found that 15% of wine/beverage coolers used vapor compression cooling technology, while 85% used thermoelectric cooling technology, with the vast majority of thermoelectric units having capacities of less than 30 wine bottles (approximately 3.5 cubic feet). No evidence was found for the existence of wine/beverage coolers with absorption cooling technology. Additionally, we estimated

  10. U.S. Residential Miscellaneous Refrigeration Products: Results from Amazon Mechanical Turk Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Greenblatt, Jeffery B.; Young, Scott J.; Yang, Hung-Chia; Long, Timothy; Beraki, Bereket; Price, Sarah K.; Pratt, Stacy; Willem, Henry; Desroches, Louis-Benoit

    2013-11-14

    Amazon Mechanical Turk was used, for the first time, to collect statistically representative survey data from U.S. households on the presence, number, type and usage of refrigerators, freezers, and various “miscellaneous” refrigeration products (wine/beverage coolers, residential icemakers and non-vapor compression refrigerators and freezers), along with household and demographic information. Such products have been poorly studied to date, with almost no information available about shipments, stocks, capacities, energy use, etc. A total of 9,981 clean survey responses were obtained from five distinct surveys deployed in 2012. General refrigeration product survey responses were weighted to demographics in the U.S. Energy Information Administration’s Residential Energy Consumption Survey 2009 dataset. Miscellaneous refrigeration product survey responses were weighted according to demographics of product ownership found in the general refrigeration product surveys. Model number matching for a portion of miscellaneous refrigeration product responses allowed validation of refrigeration product characteristics, which enabled more accurate estimates of the penetrations of these products in U.S. households. We estimated that there were 12.3±1.0 million wine/beverage coolers, 5.5(–3.5,+3.2) million residential icemakers and 4.4(–2.7,+2.3) million non-vapor compression refrigerators in U.S. households in 2012. (All numerical results are expressed with ranges indicating the 95% confidence interval.) No evidence was found for the existence of non-vapor compression freezers. Moreover, we found that 15% of wine/beverage coolers used vapor compression cooling technology, while 85% used thermoelectric cooling technology, with the vast majority of thermoelectric units having capacities of less than 30 wine bottles (approximately 3.5 cubic feet). No evidence was found for the existence of wine/beverage coolers with absorption cooling technology. Additionally, we estimated

  11. 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...

  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. A review of carbon dioxide as a refrigerant in refrigeration technology

    Directory of Open Access Journals (Sweden)

    Paul Maina

    2015-09-01

    Full Text Available Tough environmental laws and stringent government policies have revolutionised the refrigeration sector, especially concerning the cycle fluid known as the refrigerant. It has been observed that only natural refrigerants are environmentally benign. When other refrigerant qualities are considered, especially those relating to toxicity and flammability, carbon dioxide emerges as the best among the natural refrigerants. However, carbon dioxide based refrigerants are not without drawbacks. Even though the use of R744 a carbon dioxide based refrigerant gas has solved the direct effect of emissions on the environment, studies to investigate the indirect effects of these systems are needed. Improvement in existing technical solutions and the formulation of additional solutions to existing R744 refrigeration problems is paramount if this technology is to be accepted by all, especially in areas with warm climates. National policies geared to green technologies are important to clear the way and provide support for these technologies. It is clear that carbon dioxide is one of the best refrigerants and as environmental regulations become more intense, it will be the ultimate refrigerant of the future.

  16. 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.

  17. New refrigeration system using CO2 vapor-solid as refrigerant

    Institute of Scientific and Technical Information of China (English)

    Dongping HUANG; Guoliang DING; Hans QUACK

    2008-01-01

    A refrigerant must be in the vapor-liquid phase in a vapor-compression refrigeration system, therefore, CO2 cannot be used as a refrigerant for temperatures lower than -56℃ because solid CO2 will form under the triple point temperature of -56℃. A refrigeration system with CO2 vapor-solid particles as refrigerant is put forward, by which a temperature lower than the triple point is achieved. An adjustable nozzle, a sublimator, a high-pressure regulating valve and a low-pressure regulat-ing valve are used to replace the conventional evaporator. Theoretical cycle analysis of the refrigeration system shows that its COP can be 50% higher than that of the conventional one.

  18. Harmful and Needless Emission of Refrigerant and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    Wu Zeqiu

    2009-01-01

    Refrigerants used in refrigerators are an important source of ozone depleting substances released into the atmosphere,and can have a significantly negative effect on the hole in the ozone layer.But most emission of refrigerants is man-made,unreasonable and needless.Since in most emission cases the refrigerants are contained in the refrigerators,we can retrieve them by some technique that changes the 'manual emission' into manual retrieving.To promote the retrieval action and diminish the pollution,society can use economic,administrative and technical countermeasures,which can create a 'good-cycle' both 'harnessing pollution and earning income simultaneously',reinforce the motive of retrieving,and retrieve most proportion of refrigerants used by all refrigerators.This 'good-cycle' method can be easily promoted,and also a valuable way to promote other forms of environmental protection.The three countermeasures have almost no social cost,even no cost at all.

  19. 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.

  20. Experience with two large-scale Hell-cryostats for a superconducting RF particle separator working in closed cycle with a 300 W refrigerator

    CERN Document Server

    Barth, W

    1976-01-01

    The contribution of the Karlsruhe Institut fur Experimental Kernphysik to the RF particle separator at the SPS/CERN consists of the two superconducting deflectors and their Hell-cryostats with the cryogenic and vacuum accessories. The cryostats have to fulfil specifications concerning tightness, thermal insulation, adjustment of the cavities to the beam and reliability. Corresponding cryogenic and RF tests are performed in Karlsruhe before a 300 W refrigerator simulating normal and emergency conditions. Following a description of cryostats design the results of these measurements are compared with the specifications. Operating experience with the cryostats in closed circuit with the refrigerator are reported. (5 refs).

  1. 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

  2. Cycle performance studies on a new HFC-161/125/143a mixture as an alternative refrigerant to R404A

    Institute of Scientific and Technical Information of China (English)

    Xiao-hong HAN; Yu QIU; Ying-jie XU; Men-yuan ZHAO; Qin WANG; Guang-ming CHEN

    2012-01-01

    In this paper,a new ternary non-azeotropic mixture of HFC-161/125/143a (0.15/0.45/0.40 in mass fraction),as a promising mixed refrigerant to R404A,is presented.The ozone depletion potential (ODP) of the new refrigerant is zero and its basic thermodynamic properties are similar to those of R404A,but its global warming potential (GWP) is much smaller than those of R507A and R404A.Meanwhile,theoretical calculations show that,under the working condition Ⅰ (the average evaporation temperature:-23 ℃,the average condensing temperature:43 ℃,the superheat temperature:28 ℃,the subcooling temperature:5 ℃),the volumetric refrigerating effect and specific refrigerating effect of the new mixture are 2.33% and 15.48% higher,respectively,than those of R404A.The coefficient of performance (COP) of the new mixture is 5.19% higher than that of R404A and the pressure ratio of the new mixture is 0.82% lower than that of R404A.Equally,under the working condition Ⅱ (the average evaporation temperature:-40 ℃,the average condensing temperature:35 ℃,the superheating temperature:30 ℃,the subcooling temperature:5 ℃),the volumetric refrigerating effect and specific refrigerating effect of the new mixture are 2.24% and 20.58% higher,respectively,than those of R404A.The COP of the new mixture is 4.60% higher than that of R404A and the pressure ratio of the new mixture is similar to that of R404A.The performances of the new mixture and R404A are compared in a vapor compressor refrigeration apparatus originally designed for R404A under several working conditions (condensing temperatures:35-45 ℃,evaporation temperatures:-40-20 ℃).Experimental results show that the new mixture can obtain a higher COP,by 6.3% to 12.1%,and a lower pressure ratio,by 1.8% to 6.6%,compared to R404A; although the discharge temperature of the new mixture is slightly higher than that of R404A.The advantages of the new mixture will be further verified in the actual system.

  3. Corrosion Problems in Absorption Chillers

    Science.gov (United States)

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  4. A Ross-Stirling spacecraft refrigerator

    Science.gov (United States)

    Walker, G.; Scott, M.; Zylstra, S.

    A spacecraft refrigerator was investigated capable of providing cooling for storage of food and biological samples in the temperature range 0-20 F with cooling capacity in the range of 1 to 2 kW, operating for long periods with great reliability. The system operated on the Stirling refrigeration cycle using the spacecraft life-support gases as the working fluid. A prototype spacecraft Stirling refrigerator was designed, built, and tested with air as the working fluid. The system performance was satisfactory, meeting the requirements specified above. Potential applications for the prototype unit are mentioned.

  5. 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.

  6. 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...

  7. Performance Analysis of Multipurpose Refrigeration System (MRS on Fishing Vessel

    Directory of Open Access Journals (Sweden)

    Ust Y.

    2016-04-01

    Full Text Available The use of efficient refrigerator/freezers helps considerably to reduce the amount of the emitted greenhouse gas. A two-circuit refrigerator-freezer cycle (RF reveals a higher energy saving potential than a conventional cycle with a single loop of serial evaporators, owing to pressure drop in each evaporator during refrigeration operation and low compression ratio. Therefore, several industrial applications and fish storage systems have been utilized by using multipurpose refrigeration cycle. That is why a theoretical performance analysis based on the exergetic performance coefficient, coefficient of performance (COP, exergy efficiency and exergy destruction ratio criteria, has been carried out for a multipurpose refrigeration system by using different refrigerants in serial and parallel operation conditions. The exergetic performance coefficient criterion is defined as the ratio of exergy output to the total exergy destruction rate (or loss rate of availability. According to the results of the study, the refrigerant R32 shows the best performance in terms of exergetic performance coefficient, COP, exergy efficiency, and exergy destruction ratio from among the other refrigerants (R1234yf, R1234ze, R404A, R407C, R410A, R143A and R502. The effects of the condenser, freezer-evaporator and refrigerator-evaporator temperatures on the exergetic performance coefficient, COP, exergy efficiency and exergy destruction ratios have been fully analyzed for the refrigerant R32.

  8. Thermodynamics of the CO2–Absorption/Desorption Section in the Integrated Gasifying Combined cycle — II. Analysis

    Directory of Open Access Journals (Sweden)

    Jaroslav KOZACZKA

    2012-06-01

    Full Text Available The thermodynamic analysis of the absorption/desorption section of the ICGC–cycle has been presented using the Second Law with special emphasis on the thermodynamic effectivity concept and usability for complex systems investigations. Essential problems have been discussed based on the classical bibliographical items on the subject. Numerical calculations have been accomplished using results obtained in the first part, which contained absorption and desorption modeling approach oriented onto thermodynamic analyzes. Additionally the special properties of dilute solutions, especially the CO2/water system, have been presented and the problem of the solute chemical concentration exergy change suggested.

  9. 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.

  10. Simulated performance of biomass gasification based combined power and refrigeration plant for community scale application

    Energy Technology Data Exchange (ETDEWEB)

    Chattopadhyay, S., E-mail: suman.mech09@gmail.com [Department of Mechanical Engineering, NIT, Agarpara, Kolkata – 700109, West Bengal (India); Mondal, P., E-mail: mondal.pradip87@gmail.com; Ghosh, S., E-mail: sudipghosh.becollege@gmail.com [Department of Mechanical Engineering, IIEST, Shibpur, Howrah – 711103, West Bengal (India)

    2016-07-12

    Thermal performance analysis and sizing of a biomass gasification based combined power and refrigeration plant (CPR) is reported in this study. The plant is capable of producing 100 kWe of electrical output while simultaneously producing a refrigeration effect, varying from 28-68 ton of refrigeration (TR). The topping gas turbine cycle is an indirectly heated all-air cycle. A combustor heat exchanger duplex (CHX) unit burns producer gas and transfer heat to air. This arrangement avoids complex gas cleaning requirements for the biomass-derived producer gas. The exhaust air of the topping GT is utilized to run a bottoming ammonia absorption refrigeration (AAR) cycle via a heat recovery steam generator (HRSG), steam produced in the HRSG supplying heat to the generator of the refrigeration cycle. Effects of major operating parameters like topping cycle pressure ratio (r{sub p}) and turbine inlet temperature (TIT) on the energetic performance of the plant are studied. Energetic performance of the plant is evaluated via energy efficiency, required biomass consumption and fuel energy savings ratio (FESR). The FESR calculation method is significant for indicating the savings in fuel of a combined power and process heat plant instead of separate plants for power and process heat. The study reveals that, topping cycle attains maximum power efficiency of 30%in pressure ratio range of 8-10. Up to a certain value of pressure ratio the required air flow rate through the GT unit decreases with increase in pressure ratio and then increases with further increase in pressure ratio. The capacity of refrigeration of the AAR unit initially decreases up to a certain value of topping GT cycle pressure ratio and then increases with further increase in pressure ratio. The FESR is found to be maximized at a pressure ratio of 9 (when TIT=1100°C), the maximum value being 53%. The FESR is higher for higher TIT. The heat exchanger sizing is also influenced by the topping cycle pressure ratio

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  12. 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.

  13. 跨临界CO2引射制冷循环运行稳定性研究%The Operation Stability Research on the Transcritical CO2 Ejector Expansion Refrigeration Cycle

    Institute of Scientific and Technical Information of China (English)

    邓建强

    2011-01-01

    Present work analyzed the operation stability of the transcritical CO2 ejector expansion refrigeration cycle. Thermodynamic models of two kinds adjusting schemes which maintain cycle stable, i.e. feedback vapor and two-stage evaporation were set up. The simulation result shows that cycle with vapor feedback adjusting control has highly similar refrigeration effect with the basic ejector expansion cycle which controlled by the entrainment ratio. The cycle with two-stage evaporation improves the refrigeration performance obviously. The adjustable district of vapor feedback control becomes narrower with the entrainment ratio decreasing. By contrast, the adjustable district of the two-stage evaporation control broadens. With regards to the vapor feedback adjusting control, considering the optimize of the COP and the wider adjustable working condition, the ejector coefficient is suitable in 0.6-0.7.%分析了跨临界CO2引射制冷循环的运行稳定性问题,对蒸气反馈和两级蒸发两种致引射系统稳定的调控方案构建了热力学模型。模拟研究表明蒸气反馈调控系统具有与基本引射循环调控引射系数致系统稳定非常相似的制冷效果。而两级蒸发调控可明显提高系统的制冷性能。引射系数越小,蒸气反馈调控的可调工况区间越窄,两级蒸发方案的可调工况区间越宽。对于蒸气反馈调控,同时考虑COP优化和具较宽的可调工况,引射系数在0.6-0.7间较合适。

  14. 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.)

  15. 太阳能水蒸气引射冷却的CO2低温制冷循环%CO2 Refrigeration Cycle of Solar Energy Water Vapor Entrainment Cooling for Low Temperature

    Institute of Scientific and Technical Information of China (English)

    宁静红; 刘圣春; 郭宪民

    2012-01-01

    为需要较低温度的用冷空间提供冷源,设计由太阳能集热循环,水蒸气喷射制冷循环,CO2低温制冷循环组成的太阳能辅助热源水蒸气喷射引射冷却的CO2低温制冷的组合循环,通过热力计算得出随着蒸发温度的升高,太阳能辐射强度的增大,集热器面积的增大,组合循环的性能提高.蒸发温度每升高1℃,组合循环的性能系数增大4.3%,太阳能辐射强度每增加1 W/m2,组合循环的性能系数增大2.8%,太阳能集热器面积每增加1 m2,组合循环的性能系数增大约6%.发生器内水蒸气温度对组合循环的性能影响不大,太阳能辐射强度、集热器面积以及喷射器引射率对组合循环的影响较大.组合循环节省运行费用,节约能源,有很好的发展前景.%The combined cycle of solar energy - driven water vapor ejector entrainment cooling CO2 refrigeration cycle is designed for providing low temperature space. This combined cycle is composed of solar energy heat-collecting cycle, water vapor e-jector refrigeration cycle and CO2 low temperature refrigeration cycle. By thermodynamic calculation, the results are obtained that the COP of combined cycle increase as the enhancing of evaporation temperature, solar energy radiant intensity and solar collector area. When the evaporation temperature increase 1℃ , the COP of combined cycle enhance about 4.3% , the radiant intensity of solar energy increase 1 W/m2, the COP of combined cycle enhance about 2. 8% , and the solar collector area increase lm2, the COP of combined cycle enhance about 6% . However, the effect of water vapor temperature in generator on the performance of combined cycle is not obvious. Moreover the effect of the solar energy radiant intensity, the solar collector area and the ejector entrainment ratio are higher on the COP of combined cycle. It is gained that the performance of combined system has obvious advantage for reducing running cost and saving energy, so

  16. Development of Exhaust Gas Driven Absorption Chiller-Heater

    Science.gov (United States)

    Inoue, Naoyuki; Endou, Tetsuya; Saito, Kiyoshi; Kawai, Sunao

    Waste heat from co-generation systems are usually recovered by hot water or steam, those are used to drive absorption refrigerators at cooling time, and those are used for heating via heat exchangers at heating time. However waste heat from micro gas turbines are discharged in the form of exhaust gas, it is simple that exhaust gas is directly supplied to absorption chiller-heaters. In the first report we studied cooling cycle, and this second paper, we evaluated various absorption heating cycles for exhaust gas driven absorption chiller-heaters, and adopted one of these cycles for the prototype machine. Also, we experimented with the prototype for wide range condition and got the heating characteristics. Based on the experimental data, we developed a simulation model of the static characteristics, and then studied how to increase the output by limited exhaust gas.

  17. Shuttle Kit Freezer Refrigeration Unit Conceptual Design

    Science.gov (United States)

    Copeland, R. J.

    1975-01-01

    The refrigerated food/medical sample storage compartment as a kit to the space shuttle orbiter is examined. To maintain the -10 F in the freezer kit, an active refrigeration unit is required, and an air cooled Stirling Cycle refrigerator was selected. The freezer kit contains two subsystems, the refrigeration unit, and the storage volume. The freezer must provide two basic capabilities in one unit. One requirement is to store 215 lbs of food which is consumed in a 30-day period by 7 people. The other requirement is to store 128.3 lbs of medical samples consisting of both urine and feces. The unit can be mounted on the lower deck of the shuttle cabin, and will occupy four standard payload module compartments on the forward bulkhead. The freezer contains four storage compartments.

  18. Defrost Temperature Termination in Supermarket Refrigeration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A [ORNL; Sharma, Vishaldeep [ORNL

    2011-11-01

    The objective of this project was to determine the potential energy savings associated with implementing demand defrost strategies to defrost supermarket refrigerated display case evaporators, as compared to the widely accepted current practice of controlling display case defrost cycles with a preset timer. The defrost heater energy use of several representative display case types was evaluated. In addition, demand defrost strategies for refrigerated display cases as well as those used in residential refrigerator/freezers were evaluated. Furthermore, it is anticipated that future work will include identifying a preferred defrost strategy, with input from Retail Energy Alliance members. Based on this strategy, a demand defrost system will be designed which is suitable for supermarket refrigerated display cases. Limited field testing of the preferred defrost strategy will be performed in a supermarket environment.

  19. 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

  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. 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

  2. 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.

  3. 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.

  4. Evaluation of the column components size on the vapour enrichment and system performance in small power NH{sub 3}-H{sub 2}O absorption refrigeration machines

    Energy Technology Data Exchange (ETDEWEB)

    Sieres, Jaime; Fernandez-Seara, Jose [Area de Maquinas y Motores Termicos, Escuela Tecnica Superior de Ingenieros Industriales, Universidad de Vigo, Vigo (Spain)

    2006-06-15

    This paper presents an analysis of the influence of the distillation column components size on the vapour enrichment and system performance in small power NH{sub 3}-H{sub 2}O absorption machines with partial condensation. It is known that ammonia enrichment is required in this type of systems; otherwise water accumulates in the evaporator and strongly deteriorates the system performance and efficiency. The distillation column analysed consists of a stripping adiabatic section below the column feed point and an adiabatic rectifying packed section over it. The partial condensation of the vapour is produced at the top of the column by means of a heat integrated rectifier with the strong solution as coolant and a water cooled rectifier. Differential mathematical models based on mass and energy balances and heat and mass transfer equations have been developed for each one of the column sections and rectifiers, which allow defining their real dimensions. Results are shown for a given practical application. Specific geometric dimensions of the column components are considered. Different distillation column configurations are analysed by selecting and discarding the use of the possible components of the column and by changing their dimensions. The analysis and comparison of the different column arrangements has been based on the system COP and on the column dimensions. (author)

  5. 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.)

  6. CO2LD: An Educational Innovation Project for Advanced Vocational Training in Refrigeration

    Science.gov (United States)

    Sánchez, Daniel; Llopis, Rodrigo; Patiño, Jorge; Cabello, Ramón; Torrella, Enrique

    2013-01-01

    Refrigeration is one of the technology sectors that has suffered the most changes in the last twenty years, because of the negative impact of the fluids used in the refrigeration cycles, i.e., refrigerants, due to their impact on the ozone layer and their contribution to global warming. As a result of their negative effects, the European Union has…

  7. 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.

  8. 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.

  9. Optimization on oil vapor condensing recovery system by mixed refrigerant cycle%基于混合制冷剂循环的油气冷凝回收系统优化

    Institute of Scientific and Technical Information of China (English)

    郭兴龙; 宋新南

    2012-01-01

    油品在储运过程中,部分轻烃组分挥发会造成资源浪费和环境污染,油气冷凝回收法以其经济性和可靠性已成为有效的油气污染控制方法之一.文中提出了一种基于混合制冷剂循环的油气冷凝回收系统,与现有的复叠式系统相比,该系统流程简单、结构紧凑、运行经济性显著.介绍了该系统的主要组成和工作原理,建立了系统热力学优化模型,以典型的挥发油气工况为输入参数,研究了混合制冷剂配比以及各级冷凝温度对系统性能的影响.研究结果表明:高沸点组分比例的提高能够降低系统能耗,一级冷凝温度对系统性能有显著影响,二级冷凝温度对系统性能影响有限,与复叠式系统相比,混合制冷剂系统的每方油气处理功耗可降低23~48%.%Light hydrocarboncompons of petroleum products can evaporate in the process of stockpiling and transportation, which cause energy consumption and enviroment pollution. Condensation has become one of the effective method for oil vapor re covery. An oil vapor condensing recovery system by mixed refrigerant cycle was proposed, which was more simpler and economi cer compared to the cascaed condesation method. The composing and principle of the mixed refrigerant cycle were presented, the thermodynamic optimization model was built up, for the typical oil vapor soure the effect of the composition of the mixed refriger ant and the various level condensating temperatures on the system was studied. The results show that with the increasing of the componet with high boil point, the power comsumption can be decreased; the effect of the first level condensing temperature is notable on the system, and that of the second level condensing temperature is limited; the power consumption can be reduced by 23-48% by the mixed refrigerant system compared to the cascaed system.

  10. 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.

  11. Optimization of energy plants including water/lithium bromide absorption chillers

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J.C.; Castells, F. [Universitat Rovira i Virgili, Dept. d' Enginyeria Quimica, Tarragona (Spain); Miquel, J. [Universitat Politecnica de Catalunya, Dept. de Mecanica de Fluids, Barcelona (Spain)

    2000-07-01

    In this paper a methodology for the optimal integration of water/lithium bromide absorption chillers in combined heat and power plants is proposed. This method is based on the economic optimisation of an energy plant that interacts with a refrigeration cycle, by using a successive linear programming technique (SLP). The aim of this paper is to study the viability of the integration of already technologically available absorption chillers in CHP plants. The results of this alternative are compared with the results obtained using the conventional way of producing chilled water, that is, using mechanical vapour compression chillers in order to select the best refrigeration cycle alternative for a given refrigeration demand. This approach is implemented in the computer program XV, and tested using the data obtained in the water/LiBr absorption chiller of Bayer in Tarragona (Catalonia, Spain). The results clearly show that absorption chillers are not only a good option when low-cost process heat is available, but also when a cogeneration system is presented. In this latter case, the absorption chiller acts as a bottoming cycle by using steam generated in the heat recovery boiler. In this way, the cogeneration size can be increased producing higher benefits than those obtained with the use of compression chillers. (Author)

  12. Steady state simulation of a double-effect steam absorption chiller

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.S.A.M.S.; Gilani, S.I.U.H. [Universiti Teknologi Petronas, Tronoh, Perak (Malaysia). Dept. of Mechanical Engineering

    2011-07-01

    Absorption cooling systems have become increasingly popular in recent years from the viewpoint of energy and environment. Despite a lower coefficient of performance (COP) as compared to the vapor compression, absorption refrigeration systems are attractive for using inexpensive waste heat, solar, geothermal or biomass energy sources for which the cost of supply is negligible in many cases. In addition absorption refrigeration uses natural substances which do not contribute towards ozone depletion and global warming. Owing to the serious environmental problems and the price of the traditional energy resources, the use of industrial waste heat or renewable energy as the driving force for vapor absorption cooling systems is continuously increasing. A steady-state model is developed to predict the performance of an absorption refrigeration system using LiBr-water as working pair. Each component of the cycle is modelled based on mass and energy balances. The design point parameters are determined. The refrigeration effect, coefficient of performance and load factor are analyzed for different heat input. Simulation is carried out and the results are compared with actual data and showed good agreement.

  13. 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.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    Ahmed Mojahid Sid Ahmed Mohammed Salih

    2014-07-01

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

  16. Construction of a 2 kW/4 K Helium Refrigerator for HT-7U

    Institute of Scientific and Technical Information of China (English)

    白红宇; 毕延芳; 王金荣; 庄明; 朱平; 张启勇; 盛林海

    2002-01-01

    Superconducting magnets of toroidal field (TF) and poloidal field (PF) of HT-7U tokamak are all made of NbTi/Cu Cable-in-Conduit Conductor (CICC), and cooled with a forced flow supercritical helium of 3.8 K. A helium refrigerator with an equivalent capacity of 2 kW/4 K will be constructed. This paper presents the design of the helium refrigerator process, the thermodynamics of the refrigeration cycle and the refrigerator equipments.

  17. Natural refrigerants. Future heat pumps for district heating; Naturliga koeldmedier. Framtida vaermepumpar foer fjaerrvaerme

    Energy Technology Data Exchange (ETDEWEB)

    Ingvarsson, Paul; Steen Ronnermark, Ingela [Fortum Teknik och Miljoe AB, Stockholm (Sweden); Eriksson, Marcus [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Chemical Engineering and Environmental Science

    2004-01-01

    improvement in components, system and external preconditions. In the future it might be more interesting to use turbine driven heat pumps instead of electric motors. The absorption process is not considered to be an alternative to replace present heat pumps, but there is a certain niche where heat source and driving energy, considering temperature levels, are more suitable for district heating. A technique that seems to be an alternative to the compression cycle is a combination of compression and absorption. Using the media pair water and ammonia might be an interesting solution and should be compared to the alternative using carbon dioxide. A further study is recommended on this subject.

  18. EXERGETIC PERFORMANCE OF A DOMESTIC REFRIGERATOR USING R12 AND ITS ALTERNATIVE REFRIGERANTS

    Directory of Open Access Journals (Sweden)

    BUKOLA O. BOLAJI

    2010-12-01

    Full Text Available Production and use of R12 and other chlorofluorocarbon refrigerants will be prohibited completely all over the world in the year 2010 due to their harmful effects on the earth’s protective ozone layer. Therefore, in this study, the exergetic performance of a domestic refrigerator using two environment-friendly refrigerants (R134a and R152a was investigated and compared with the performance of the system when R12 (an ozone depleting refrigerant was used. The effects of evaporator temperature on the coefficient of performance (COP, exergy flow destruction, exergetic efficiency and efficiency defect in the four major components of the cycle for R12, R134a and R152a were experimentally investigated. The results obtained showed that the average COP of R152a was very close to that of R12 with only 1.4% reduction, while 18.2% reduction was obtained for R134a in comparison with that of R12. The highest average exergetic efficiency of the system (41.5% was obtained using R152a at evaporator temperature of -3.0oC. The overall efficiency defect in the refrigeration cycle working with R152a is consistently better (lower than those of R12 and R134a. Generally, R152a performed better than R134a in terms of COP, exergetic efficiency and efficiency defect as R12 substitute in domestic refrigeration system.

  19. Numerical analysis on transcritical CO2 vapor compression/ejection refrigeration cycle%跨临界CO2蒸气压缩/喷射制冷循环的数值分析

    Institute of Scientific and Technical Information of China (English)

    黄惠兰; 韩美健; 李刚; 郑克敏

    2014-01-01

    为了更合理的描述喷射器扩压室内的压力变化特性,对已有的跨临界CO2蒸气压缩/喷射制冷循环的热力学模型做了改进,并对扩压室新定义了一种压力系数ηd。建立了相应的数学模型并进行数值模拟,考察了该压力系数ηd 对制冷循环喷射系数和系统性能系数COP的影响,其结果与常规的扩压效率ηk 的影响作用有很好的一致性,说明所改进的热力学模型是可行的;应用该模型分析了压力系数对相关重要参数的影响,结果表明:随压力系数的增大,喷射系数基本不变;COP、压缩机进口温度、喷射器的增压比和喷射器效率增大;压缩机出口温度和压缩比减小;当工作流体压力为9 MPa时,相关参数发生了显著的变化。该压力系数取决于系统喷射器扩压室进出口的压力,方便测量确定。研究方法能够为跨临界CO2蒸气压缩/喷射制冷循环的性能分析提供有益参考。%A thermodynamic model of transcritical CO2 vapor-compression/ejection refrigeration cy-cle was modified to display the pressure variation in diffuser chamber of the ejector. A new pressure coefficient ηd for diffuser chamber was defined. And the corresponding mathematical model was es-tablished for calculated analysis. The effects of the pressure coefficientηd to the ejector entrainment ratio and the coefficient of performance ( COP) of the refrigeration cycle were studied. The results are in good agreement with the effects of common diffuser efficiencyηk . It is shown that the modified thermodynamic model is feasible. The influences of the pressure coefficient on several important pa-rameters were investigated. The results show that the ejector entrainment ratio almost unchanged with the increasing pressure coefficient. And the cycle COP, compressor inlet temperature, ejector pres-sure ratio and ejector efficiency increase with the increasing pressure coefficient. The compressor

  20. In situ characterization of few-cycle laser pulses in transient absorption spectroscopy

    CERN Document Server

    Blättermann, Alexander; Kaldun, Andreas; Ding, Thomas; Stooß, Veit; Laux, Martin; Rebholz, Marc; Pfeifer, Thomas

    2016-01-01

    Attosecond transient absorption spectroscopy has thus far been lacking the capability to simultaneously characterize the intense laser pulses at work within a time-resolved quantum-dynamics experiment. However, precise knowledge of these pulses is key to extracting quantitative information in strong-field highly nonlinear light-matter interactions. Here, we introduce and experimentally demonstrate an ultrafast metrology tool based on the time-delay-dependent phase shift imprinted on a strong-field driven resonance. Since we analyze the signature of the laser pulse interacting with the absorbing spectroscopy target, the laser pulse duration and intensity are determined in situ. As we also show, this approach allows for the quantification of time-dependent bound-state dynamics in one and the same experiment. In the future, such experimental data will facilitate more precise tests of strong-field dynamics theories.

  1. In situ characterization of few-cycle laser pulses in transient absorption spectroscopy.

    Science.gov (United States)

    Blättermann, Alexander; Ott, Christian; Kaldun, Andreas; Ding, Thomas; Stooß, Veit; Laux, Martin; Rebholz, Marc; Pfeifer, Thomas

    2015-08-01

    Attosecond transient absorption spectroscopy has thus far been lacking the capability to simultaneously characterize the intense laser pulses at work within a time-resolved quantum-dynamics experiment. However, precise knowledge of these pulses is key to extracting quantitative information in strong-field highly nonlinear light-matter interactions. Here, we introduce and experimentally demonstrate an ultrafast metrology tool based on the time-delay-dependent phase shift imprinted on a strong-field-driven resonance. Since we analyze the signature of the laser pulse interacting with the absorbing spectroscopy target, the laser pulse duration and intensity are determined in situ. As we also show, this approach allows for the quantification of time-dependent bound-state dynamics in one and the same experiment. In the future, such experimental data will facilitate more precise tests of strong-field dynamics theories.

  2. Optimal performance of a quantum Otto refrigerator

    Science.gov (United States)

    Abah, Obinna; Lutz, Eric

    2016-03-01

    We consider a quantum Otto refrigerator cycle of a time-dependent harmonic oscillator. We investigate the coefficient of performance at maximum figure of merit for adiabatic and nonadiabatic frequency modulations. We obtain analytical expressions for the optimal performance both in the high-temperature (classical) regime and in the low-temperature (quantum) limit. We moreover analyze the breakdown of the cooling cycle for strongly nonadiabatic driving protocols and derive analytical estimates for the minimal driving time allowed for cooling.

  3. Potential of the tractor-trailer and container segments as entry markets for a proposed refrigeration technology

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.A.; Davis, L.J.; Garrett, B.A.

    1987-05-01

    The refrigerated trailer and container segments of the transportation industry are evaluated as potential entry markets for a proposed absorption refrigeration technology. To perform this analysis the existing transportation refrigeration industry is characterized; this includes a description of the current refrigeration technology, rating systems, equipment manufacturers, maintenance requirements, and sales trends. This information indicates that the current transportation refrigeration industry is composed of two major competitors, Thermo King and Carrier. In addition, it has low profit potential, some barriers to entry and low growth potential. Data are also presented that characterize the transportation refrigeration consumers, specifically, major groups, market segmentation, consumer decision process, and buying criteria. This consumer information indicates that the majority of refrigerated trailer consumers are private carriers, and that the majority of refrigerated container consumers are shipping companies. Also, these consumers are primarily interested in buying reliable equipment at a low price, and are quite satisfied with existing refrigeration equipment.

  4. 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.

  5. Energy Absorption in a Load-Unload Cycle of Knee Implant Using Fractal Model of Rough Surfaces

    Science.gov (United States)

    Hodaei, Mohammad; Farhang, Kambiz

    2016-05-01

    Roughness measurement of knee implant surfaces is investigated. The study of roughness measurement show that the topography of knee implant surface is multi-scale and surface spectra follows a power law behavior. A magnification of rough surface topography implies that there is no difference between original and magnified profile of implant surface. For implant surface, statistical parameters such as variance of height, curvature, and slope are found to be scale-dependent. Fractal representation of implant surface shows that the size-distribution of the multi-scale contacts spots follows a power law and is characterized by the fractal dimension of implant surface. Fractal surface description of the rough surfaces of knee implant is used to obtain force-displacement relationship of the contact force. Using an approximate function through the fusion of two piecewise functions, energy absorption of a knee implant in a single cycle of load-unload is obtained.

  6. 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.

  7. 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.

  8. 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}.

  9. 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...

  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. 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

  12. 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.

  13. A novel integrated cascade absorption refrigeration technology by using waste heat in CTG’s methanation process%煤制气中甲烷化余热利用集成串级吸收式制冷新工艺

    Institute of Scientific and Technical Information of China (English)

    杨声; 梁嘉能; 杨思宇; 钱宇

    2016-01-01

    煤制气甲烷化过程中会产生大量的低温余热,这部分热量直接排放到大气,造成较大的能效损失、经济价值损失。将溴化锂吸收式制冷和氨吸收式制冷的串级制冷工艺集成到甲烷化过程中,利用低品位余热制冷,可制得−40℃的冷量用于低温甲醇洗,以替代部分常规的压缩式制冷。这样能大幅降低电耗,提高能效。以40亿立方米/年的煤制天然气为例,该串级吸收式制冷集成甲烷化过程中的低温余热用于低温甲醇洗单元供冷,减少压缩式制冷负荷16.2%,折合节省标煤1.8万吨/年,动态投资回收期1.7年左右。%Methanation process in coal to synthetic natural gas (CTG) produces a large amount of waste heat. It will cause a huge loss of economic value and energy efficiency with this part of heat emitted into the atmosphere directly. LiBr absorption refrigeration and NH3 absorption refrigeration cascade refrigeration technology (CRT) is driven by waste heat from methanation process. CRT can produce−40℃ ammonia used in rectisol which can replace a part of compression refrigeration. Thus, it can reduce power consumption significantly and increase energy utilization efficiency. For example, CRT is integrated with methanation applied in a 4 billion m3·a−1 SNG plant. As a result, 16.2% compression refrigeration load is substituted, equivalent to saving 18000 tons standard coal per year. The dynamic payback period is about 1.7 years.

  14. 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.

  15. Investigation of active-buffer pulse tube refrigerator

    Science.gov (United States)

    Zhu, Shaowei; Kakimi, Yasuhiro; Matsubara, Yoichi

    An active-buffer pulse tube refrigerator, which is a GM type pulse tube refrigerator, is described in this paper. Two or more buffers are connected at the hot end of the pulse tube through on/off valves. The main purpose of this method is to increase the efficiency. A numerical method is introduced to analyse the working process. To understand the basic mechanism, an ideal cycle is also introduced. With a prototype single stage active-buffer pulse tube refrigerator, a cooling capacity of 166 W and a percent Carnot of 13% at 80 K have been obtained.

  16. Theoretical thermodynamics analysis of cooling cycle bu advanced gas absorption using solar energy; Analisis teorico-experimental de un ciclo de refrigeracion por absorcion avanzado gax, operando con energia solar

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, V. E.; Vidal, A. S.; Garcia, C. A.; Garcia-Valladares, O.; Best, R. B.; Hernandez, J. G.; Velazquez, N. L.

    2004-07-01

    In this article a solar system of refrigeration by absorption with heat exchange generator absorber (GAX) was analyzed. A theoretical thermodynamic analysis of the energetic behavior of the GAX absorption system was made. Experimental results were obtained with generation temperatures of 190 and 220 C, the evaporation temperature was set at 9 C and temperatures of cooling fluids (air and water) were set at 30 C and 28 C, respectively. It was possible to appreciate that the GAX effect decrease whether absorber, type falling film, is operated in option of parallel flow and it was increased when the absorber was operated in option of counterflow. (Author)

  17. 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.

  18. 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.

  19. 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.

  20. 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)

  1. 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.

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

    Science.gov (United States)

    Kuu, Wei Y; Nail, Steven L

    2009-09-01

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

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. Mixed refrigerant composition shift due to throttle valves opening in auto cascade refrigeration system

    Institute of Scientific and Technical Information of China (English)

    Xiongwen Xu; Jinping Liu; Le Cao

    2015-01-01

    Auto cascade refrigeration (ACR) cycle with phase separators is widely used in the cryogenic system. The compo-sition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of infinite volume of phase separator, ACR system with one phase separator is simulated in this paper. The variation of refrigerant composition under different valves opening is obtained. A related experimental system is set up to verify the variation. The result shows that when the valve opening connected to the evaporator increases or the valve opening under the phase separator decreases, the low-boiling component concentration of the working mixture passing through the compressor and condenser increases, while the high-boiling component concentra-tion decreases. Furthermore, the variations of condensation pressure and evaporation pressure under different valves opening are also observed. This paper is helpful to deepen the understanding of ACR system.

  10. An Evaluation of the Environmental Impact of Different Commercial Supermarket Refrigeration Systems Using Low Global Warming Potential Refrigerants

    Energy Technology Data Exchange (ETDEWEB)

    Beshr, Mohamed [University of Maryland, College Park; Aute, Vikrant [University of Maryland, College Park; Abdelaziz, Omar [ORNL; Fricke, Brian A [ORNL; Radermacher, Reinhard [University of Maryland, College Park

    2014-01-01

    Commercial refrigeration systems consumed 1.21 Quads of primary energy in 2010 and are known to be a major source for refrigerant charge leakage into the environment. Thus, it is important to study the environmental impact of commercial supermarket refrigeration systems and improve their design to minimize any adverse impacts. The system s Life Cycle Climate Performance (LCCP) was presented as a comprehensive metric with the aim of calculating the equivalent mass of carbon dioxide released into the atmosphere throughout its lifetime, from construction to operation and destruction. In this paper, an open source tool for the evaluation of the LCCP of different air-conditioning and refrigeration systems is presented and used to compare the environmental impact of a typical multiplex direct expansion (DX) supermarket refrigeration systems based on three different refrigerants as follows: two hydrofluorocarbon (HFC) refrigerants (R-404A, and R-407F), and a low global warming potential (GWP) refrigerant (N-40). The comparison is performed in 8 US cities representing different climates. The hourly energy consumption of the refrigeration system, required for the calculation of the indirect emissions, is calculated using a widely used building energy modeling tool (EnergyPlus). A sensitivity analysis is performed to determine the impact of system charge and power plant emission factor on the LCCP results. Finally, we performed an uncertainty analysis to determine the uncertainty in total emissions for both R-404A and N-40 operated systems. We found that using low GWP refrigerants causes a considerable drop in the impact of uncertainty in the inputs related to direct emissions on the uncertainty of the total emissions of the system.

  11. A feasibility analysis of replacing the standard ammonia refrigeration device with the cascade NH3/CO2 refrigeration device in the food industry

    Directory of Open Access Journals (Sweden)

    Jankovich Dennis

    2015-01-01

    Full Text Available The thermodynamic analysis demonstrates the feasibility of replacing the standard ammonia refrigeration device with the cascade NH3/CO2 refrigeration device in the food industry. The main reason for replacement is to reduce the total amount of ammonia in spaces like deep-freezing chambers, daily chambers, working rooms and technical passageways. An ammonia-contaminated area is hazardous to human health and the safety of food products. Therefore the preferred reduced amount of ammonia is accumulated in the Central Refrigeration Engine Room, where the cascade NH3/CO2 device is installed as well. Furthermore, the analysis discusses and compares two left Carnot¢s refrigeration cycles, one for the standard ammonia device and the other for the cascade NH3/CO2 device. Both cycles are processes with two-stage compression and two-stage throttling. The thermodynamic analysis demonstrates that the selected refrigeration cycle is the most cost-effective process because it provides the best numerical values for the total refrigeration factor with respect to the observed refrigeration cycle. The chief analyzed influential parameters of the cascade device are: total refrigeration load, total reactive power, mean temperature of the heat exchanger, evaporating and condensing temperature of the low-temperature part.

  12. 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)

  13. 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

  14. 回热器对低温空气制冷系统性能影响的实验研究%Experimental study on effect of recuperator on air cycle refrigeration system performance

    Institute of Scientific and Technical Information of China (English)

    郭宪民; 张森林; 赵硕; 张新玉

    2014-01-01

    The performance of air cycle refrigeration system for three types of heat regenerating schemes was measured under different inlet pressures,and the effefct of the recuperator on the performance and dehumidification was also analyzed.The experimental results indicate that under the same conditions,the outlet temperature and the inlet humidity ratio of the turbine in the double recuperator system are much lower than those in the no recuperator system,and they can decrease by 8.5 ℃ and 35%,respectively.The capacity of the single and double recuperator system is much larger than that of the no recuperator system,but the first recuperator contributes slightly to the inlet humidity ratio.%随着环保问题的日益突出,空气制冷系统的理论和实验研究重新受到重视。通过对开式空气制冷系统的三种回热方案进行实验测试对比,分析了回热器对系统性能及除湿效果的影响。实验结果表明:与无回热的空气制冷系统相比,在相同的工况下,二级回热系统可大幅降低涡轮出口温度,最大降低约8.5℃,并可大幅降低涡轮进口的含湿量,最大降低约35%。同时一级回热系统和二级回热系统均可大幅增加系统的COP和制冷量,但一级回热器对涡轮进口含湿量的影响较小。

  15. 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.

  16. 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…

  17. Energy Efficiency and Environmental Impact Analyses of Supermarket Refrigeration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A [ORNL; Bansal, Pradeep [ORNL; Zha, Shitong [Hillphoenix

    2013-01-01

    This paper presents energy and life cycle climate performance (LCCP) analyses of a variety of supermarket refrigeration systems to identify designs that exhibit low environmental impact and high energy efficiency. EnergyPlus was used to model refrigeration systems in a variety of climate zones across the United States. The refrigeration systems that were modeled include the traditional multiplex DX system, cascade systems with secondary loops and the transcritical CO2 system. Furthermore, a variety of refrigerants were investigated, including R-32, R-134a, R-404A, R-1234yf, R-717, and R-744. LCCP analysis was used to determine the direct and indirect carbon dioxide emissions resulting from the operation of the various refrigeration systems over their lifetimes. Our analysis revealed that high-efficiency supermarket refrigeration systems may result in up to 44% less energy consumption and 78% reduced carbon dioxide emissions compared to the baseline multiplex DX system. This is an encouraging result for legislators, policy makers and supermarket owners to select low emission, high-efficiency commercial refrigeration system designs for future retrofit and new projects.

  18. OPTIMIZATION ANALYSIS OF THE PROCEDURE OF LIQUEFYING NATURAL GAS BY PROPANE-PRECOOLED MIXED REFRIGERANT CYCLE%带丙烷预冷的混合制冷剂循环液化天然气流程的优化分析

    Institute of Scientific and Technical Information of China (English)

    石玉美; 杨敏之; 鲁雪生; 汪荣顺

    2001-01-01

    The procedure of liquefying natural gas by propane-precooledmixed refrigerant cycle(MRC) is of the advantages as high effectiveness and relative simplification. Propane precool cycle is to precool natural gas and mixed refrigerants first, then the natural gas is further cooled and then liquefied by mixed refrigerant cycle. In the paper, through optimizing by taking the minimum power consumption of the compressor in propane precool cycle and its minimum total power consumption as the aim functions, the optimal process parameters and corresponding process performance parameters are obtained for the procedure of liquefying natural gas by propane-precooled mixed refrigerant cycle.%带丙烷预冷的混合制冷剂循环(MRC)液化天然气流程具有高效及流程相对简单的优点,丙烷预冷循环首先预冷天然气和混合制冷剂,然后由混合制冷剂循环进一步冷却天然气使其液化。本文对这种带丙烷预冷的混合制冷剂循环液化天然气流程分别以丙烷预冷循环中压缩机耗功最小、总耗功最小为目标函数进行优化,得到了最优流程参数及相应的流程性能参数。

  19. 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

  20. Effect of evaporator temperature on vapor compression refrigeration system

    Directory of Open Access Journals (Sweden)

    Abdullah A.A.A. Al-Rashed

    2011-12-01

    Full Text Available This paper presents a comparable evaluation of R600a (isobutane, R290 (propane, R134a, R22, for R410A, and R32 an optimized finned-tube evaporator, and analyzes the evaporator effect on the system coefficient of performance (COP. Results concerning the response of a refrigeration system simulation software to an increase in the amount of oil flowing with the refrigerant are presented. It is shown that there is optima of the apparent overheat value, for which either the exchanged heat or the refrigeration coefficient of performance (COP is maximized: consequently, it is not possible to optimize both the refrigeration COP and the evaporator effect. The obtained evaporator optimization results were incorporated in a conventional analysis of the vapor compression system. For a theoretical cycle analysis without accounting for evaporator effects, the COP spread for the studied refrigerants was as high as 11.7%. For cycle simulations including evaporator effects, the COP of R290 was better than that of R22 by up to 3.5%, while the remaining refrigerants performed approximately within a 2% COP band of the R22 baseline for the two condensing temperatures considered.

  1. 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.

  2. Thermal investigations of a room temperature magnetic refrigerator

    Energy Technology Data Exchange (ETDEWEB)

    Smaili, Arezki; Chiba, Younes [Ecole Nationale Polytechnique d' Alger (Algeria)], email: arezki.smaili@enp.edu.dz

    2011-07-01

    Magnetic refrigeration is a concept based on the magnetocaloric effect that some materials exhibit when the external magnetic field changes. The aim of this paper is to assess the performance of a numerical model in predicting parameters of an active magnetic regenerator refrigerator. Numerical simulations were conducted to perform a thermal analysis on an active magnetic regenerator refrigerator operating near room temperature with and without applied cooling load. Curves of temperature span, cooling capacity and thermal efficiency as functions of the operating conditions were drawn and are presented in this paper. Results showed that at fixed frequency Ql versus mf has an optimum and COP was increased with cycle frequency values. This study demonstrated that the proposed numerical model could be used to predict parameters of an active magnetic regenerator refrigerator as it provides consistent results.

  3. Synchronous temperature rate control for refrigeration with reduced energy consumption

    Science.gov (United States)

    Gomes, Alberto Regio; Keres, Stephen L.; Kuehl, Steven J.; Litch, Andrew D.; Richmond, Peter J.; Wu, Guolian

    2015-09-22

    Methods of operation for refrigerator appliance configurations with a controller, a condenser, at least one evaporator, a compressor, and two refrigeration compartments. The configuration may be equipped with a variable-speed or variable-capacity compressor, variable speed evaporator or compartment fans, a damper, and/or a dual-temperature evaporator with a valve system to control flow of refrigerant through one or more pressure reduction devices. The methods may include synchronizing alternating cycles of cooling each compartment to a temperature approximately equal to the compartment set point temperature by operation of the compressor, fans, damper and/or valve system. The methods may also include controlling the cooling rate in one or both compartments. Refrigeration compartment cooling may begin at an interval before or after when the freezer compartment reaches its lower threshold temperature. Freezer compartment cooling may begin at an interval before or after when the freezer compartment reaches its upper threshold temperature.

  4. An improved wave rotor refrigerator using an outside gas flow for recycling the expansion work

    Science.gov (United States)

    Zhao, J.; Hu, D.

    2017-03-01

    To overcome the bottleneck of traditional gas wave refrigeration, an improved wave rotor refrigerator (WRR) cycle has been proposed, in which the expansion work was recycled during the process of refrigeration. Thermodynamic analysis of the two cycles shows that the refrigeration efficiency of the improved WRR cycle has been greatly increased compared with the traditional WRR. The performance of an improved WRR was investigated by adjusting the major operational parameters, such as the rotational speed of the wave rotor, port size, and inflow overpressure. The experimental results show that pressure loss can be reduced by nearly 40 % in this improved refrigeration system. Meanwhile, a two-dimensional numerical simulation was performed to understand the wave interactions that take place inside the rotor channels.

  5. Cooling load and COP optimization of an irreversible Carnot refrigerator with spin-1/2 systems

    Directory of Open Access Journals (Sweden)

    Xiaowei Liu, Lingen Chen, Feng Wu, Fengrui Sun

    2011-09-01

    Full Text Available A model of an irreversible quantum refrigerator with working medium consisting of many non-interacting spin-1/2 systems is established in this paper. The quantum refrigeration cycle is composed of two isothermal processes and two irreversible adiabatic processes and is referred to as a spin quantum Carnot refrigeration cycle. Expressions of some important performance parameters, such as cycle period, cooling load and coefficient of performance (COP for the irreversible spin quantum Carnot refrigerator are derived, and detailed numerical examples are provided. The optimal performance of the quantum refrigerator at high temperature limit is analyzed with numerical examples. Effects of internal irreversibility and heat leakage on the performance are discussed in detail. The endoreversible case, frictionless case and the case without heat leakage are discussed in brief.

  6. Accelerated fatigue testing of aluminum refrigeration press fittings for HVAC & R applications

    OpenAIRE

    Elbel, Stefan; Duggan, Michael; LaGrotta, Tony; Raj, Sharat; Hrnjak, Pega

    2016-01-01

    Failed brazed joints causing refrigerant leakage is a multi-billion dollar problem for the global HVAC&R industry. Leaks are frequently caused due to mechanical fatigue from extreme pressure cycling, temperature cycling including exposure to freeze/thaw cycles, or vibrational wear induced from rotating electrical machinery. In this study, a new, cost-effective type of press fitting suitable for a wide variety of refrigerants and applications is investigated experimentally. Three tests to acce...

  7. Installation of a small central thermoelectric using biomass and cogeneration with absorption refrigeration system: alternative for small rural isolated communities; Instalacao de uma pequena central termeletrica a biomassa e cogeracao com sistema de refrigeracao por absorcao: alternativa para pequenas comunidades agricolas isoladas

    Energy Technology Data Exchange (ETDEWEB)

    Zukowski Junior, Joel Carlos; Marcon, Rogerio Olavo; Reys, Marcos Alves dos [Centro Universitario Luterano de Palmas (CEULP), TO (Brazil); Cortez, Luis Augusto Barbosa [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Nucleo Interdisciplinar de Planejamento Energetico (NIPE)

    2004-07-01

    The lack of electrical energy in several localities of Brazil results in a slow perspective of in terms of economic growth and scientific and technological development. In order to minimize these problems it is proposed the use of co-generation systems with small thermoelectric plants burning rice rusk (an abundant biomass in certain regions of Brazil, as for example the Tocantins State) as a heat source and to utilize the discharged steam from the turbine to generate cold through an absorption refrigeration system. The work intends to show a possible solution to the problems originated from the absence of electric power in small and isolated rural villages, also problems of processing storage of agricultural residues and to generate cold for several applications. (author)

  8. Parametric testing of a linearly driven Stirling cryogenic refrigerator

    Science.gov (United States)

    Stolfi, F. R.; Daniels, A.

    1985-05-01

    The parametric testing of a novel Stirling cycle cryogenic refrigerator which incorporates electromagnetic bearings, clearance seals and electronically controlled linear motion was studied. The last feature, which involves the use of two linear motors, position transducers and a highly accurate electronic feedback network, produces the system capability which forms the basis for the tests. The test results provide designers with an understanding of the basic operation of the Stirling cycle and give potential users some indication of the capabilities of this refrigerator under off design conditions.

  9. Materials and device concepts for electrocaloric refrigeration

    Science.gov (United States)

    Suchaneck, G.; Gerlach, G.

    2015-09-01

    Electrocaloric (EC) materials provide a solid-state cooling technology without polluting liquid refrigerants and noisy mechanical parts. Currently, basic research in this field is mainly focused on materials with a first-order phase transition exhibiting a large polarization change in a narrow temperature region near the phase transition point (Curie temperature) and, thus, a large EC effect. In this contribution, device operation above Curie temperature will be discussed. In this case, the polarization change originates from the temperature coefficient of the dielectric permittivity. To optimize material properties for EC refrigerator applications, we adapt the modified Curie-Weiss law describing a large class of ferroelectrics with a diffuse phase transition. Device performance will be evaluated based on the expected cooling power in dependence on thermodynamic cycle time, total thermal resistance and EC material thickness.

  10. 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)

  11. Energy efficient for refrigeration and air conditioning

    Directory of Open Access Journals (Sweden)

    Abdeen Mustafa Omer

    2015-03-01

    Full Text Available Over the years, all parts of a commercial refrigerator, such as the compressor, heat exchangers, refrigerant, and packaging, have been improved considerably due to the extensive research and development efforts carried out by academia and industry. However, the achieved and anticipated improvement in conventional refrigeration technology are incremental since this technology is already nearing its fundamentals limit of energy efficiency is described is ‘magnetic refrigeration’ which is an evolving cooling technology. The word ‘green’ designates more than a colour. It is a way of life, one that is becoming more and more common throughout the world. An interesting topic on ‘sustainable technologies for a greener world’ details about what each technology is and how it achieves green goals. Recently, conventional chillers using absorption technology consume energy for hot water generator but absorption chillers carry no energy saving. With the aim of providing a single point solution for this dual purpose application, a product is launched but can provide simultaneous chilling and heating using its vapour absorption technology with 40% saving in heating energy. Using energy efficiency and managing customer energy use has become an integral and valuable exercise. The reason for this is green technology helps to sustain life on earth. This not only applies to humans but to plants, animals and the rest of the ecosystem. Energy prices and consumption will always be on an upward trajectory. In fact, energy costs have steadily risen over last decade and are expected to carry on doing so as consumption grows.

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

    Science.gov (United States)

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

    2012-06-01

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

  13. 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.

  14. Construction of a 2kW/4K Helium Refrigerator for HT—7U

    Institute of Scientific and Technical Information of China (English)

    白红宇; 毕延芳; 等

    2002-01-01

    Superconducting magnets of toroidal field (TF) and poloidal field(PF) of HT-7U tokamak are all made of NbTi/Cu Cable-in-Conduit Conductor (ClCC),and cooled with a forced flow supercritical helium of 3.8K.A helium refrigerator with an equivalent capacity of 2kW/r K will be constructed.This paper presents the design of the helium refrigerator process.The thermodynamics of the refrigeration cycle and the refrigerator equipments.

  15. A Tiltable Single-Shot Miniature Dilution Refrigerator for Astrophysical Applications

    CERN Document Server

    Melhuish, Simon J; Piccirillo, Lucio

    2012-01-01

    We present a 3He / 4He dilution refrigerator designed for cooling astronomical mm-wave telescope receivers to around 100 mK. Used in combination with a Gi?fford-McMahon closed-cycle refrigerator, 4He and 3He sorption-pumped refrigerators, our cryogen-free system is capable of achieving 2 microW cooling power at 87 mK. A receiver attached directly to the telescope optics is required to rotate with respect to the downward direction. This scenario, of variable tilt, has proved difficult for typical dilution refrigerators, but our design has a geometry chosen to allow tilt to 45 degrees and beyond.

  16. 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

  17. 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。

  18. Thermodynamic Analysis of a Rankine Cycle Powered Refrigeration System Using Low-Temperature Geothermal Energy%基于有机朗肯循环的低温地热制冷系统热力学分析

    Institute of Scientific and Technical Information of China (English)

    胡冰; 马伟斌

    2014-01-01

    为有效利用低温地热资源,本文以有机朗肯-蒸汽压缩制冷系统为研究对象,建立了系统的热力学模型,分析比较了分别以R290、R600、R600a、R601、R601a和R1270为工质时的系统性能,并以系统整体COP和每kW制冷量所对应的工质流量为关键指标对工质进行了优选。分析结果表明:当地热水温度为60℃~90℃、冷凝温度为30℃~55℃、蒸发温度为-15℃~15℃时,R601是系统的最佳工质。当地热水温度为90℃,其余参数为典型工况值时,工质R601所对应的系统性能系数COP为0.49。%To efficiently utilize low-temperature geothermal energy, an organic Rankine cycle-vapor compression refrigeration (ORC-VCR) system was employed and a thermodynamic model was developed. Six working fluids of R290, R600, R600a, R601, R601a and R1270 were analyzed and evaluated in order to identify suitable working fluids which may yield high system efficiencies. The overall COP and working fluid mass flow rate of per kW cooling capacity are chosen as key performance indicators. The calculated results show that R601 is the best working fluid for the ORC-VCR system as the geothermal water temperature is between 60oC and 90oC, the condensation temperature ranges from 30oC to 55oC and the evaporation temperature varies from 30oC to 55oC. When the geothermal water temperature reaches 90oC and the other input parameters are in typical values, the overall COP of the R601 case reaches 0.49.

  19. Regulating Power from Supermarket Refrigeration

    DEFF Research Database (Denmark)

    O'Connell, Niamh; Madsen, Henrik; Pinson, Pierre

    2014-01-01

    This paper presents an analysis of the demand response capabilities of a supermarket refrigeration system, with a particular focus on the suitability for participation in the regulating power market. An ARMAX model of a supermarket refrigeration system is identified using experimental data from...... nature of demand response from refrigeration is identified as the key consideration when considering participation in the regulating power market. It is demonstrated that by restricting the operating regions of the supermarket refrigeration system, a simple relationship can be found between the available...

  20. Thermal analysis of a compound parabolic concentrator for refrigeration applications

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Naghelli; Best, Roberto [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico)

    2000-07-01

    The refrigeration system designed at the Centro de Investigacion en Energia (CIE), Mexico is able to produce, in optimal conditions, one hundred kilograms per day of ice by means of solar energy. A continuous absorption ammonia-water refrigeration cycle is employed. In its actual state, heat supply to the system is provided through a bank of evacuated tube solar collectors. Their principal difficulties encountered in this system are the indirect heat losses due to the coupling of the falling film generator to the solar heating subsystem that requires a heat transfer gradient and higher collector operating temperatures. Also the high initial cost of the evacuated tube collectors is a barrier for an economical feasible system. Currently, new types of solar collectors are being considered, more efficient and reliable, with a potentially lower cost. This type of collectors known as Compound Parabolic Collectors (CPC) succeed in working at the required temperatures for absorption refrigeration systems. Therefore, a new system is suggested and it is proposed to use a CPC array, where heat losses by the indirect heating system are avoided. In this work a simple method was developed in order to establish the energy balances in a CPC, with a steel tubular receiver without an evacuated glass shell. The receptor's model considers a bidimensional system in stationary state and it supposes a continuous medium. Four nonlinear, simultaneous equations were obtained to predict heat exchange among various components in the system. These equations were utilized in a computer program to analyze the collector performance under various operating conditions. Consequently, the prediction of temperature distribution with respect to position permits to calculate length and arrangement of the CPC for a determined refrigeration application. [Spanish] El sistema de refrigeracion en el Centro de Investigacion en Energia (CIE) Mexico es capaz de producir en condiciones optimas 100

  1. Analysis of advanced conceptual designs for single-family-sized absorption chillers. Semi-annual report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-04-05

    The objective of the research program is to develop and analyze new concepts for absorption cycles to improve the performance or reduce the cost (or both) of a 3-ton absorption chiller that can be used with solar-collected heat. New refrigerant-absorbent pairs, additives to currently used refrigerant-absorbent pairs, and modifications to the cycle are being investigated. For the initial analyses the use of a fluid at 160 to 230/sup 0/F from a solar collector as a heating source is assumed. In the initial analyses the chiller is to provide chilled water at 45/sup 0/F at full load; alternatively, if a new refrigerant-absorbent pair appears to be amenable for direct cooling of the occupied space, the temperature of the evaporator is to be 45/sup 0/F. Both water cooling and air cooling of the absorber and the condenser are being studied. The use of ambient air at 95/sup 0/F dry bulb and 75/sup 0/F wet bulb temperatures is assumed. With the water-cooled cycles, the initial and operating costs of a properly sized cooling tower will be included. The research consists of five principal tasks: (a) acquisition of information for analysis, (b) definition of criteria for selection of promising refrigerant-absorbent pairs, additives for currently used pairs, or cycle modifications, (c) preparation and analysis of conceptual designs, (d) comparison and selection of the promising new systems that warrant further study, and (e) recommendations for further research for each promising new system. Progress on each of these tasks is described. (WHK)

  2. THERMODYNAMIC PROPERTIES OF SELECTED HFC REFRIGERANTS

    Science.gov (United States)

    Hydrofluorocarbon (HFC) refrigerants are possible alternatives to replace ozone-depleting chlorofluorocarbon and hydrochlorofluorocarbon (HCFC) refrigerants. The flammability of a proposed new refrigerant is a major consideration in assessing its utility for a particular applicat...

  3. Effect of Adsorbent Diameter on the Performance of Adsorption Refrigeration

    Institute of Scientific and Technical Information of China (English)

    黄宏宇; 何兆红; 袁浩然; 小林敬幸; 赵丹丹; 窪田光宏; 郭华芳

    2014-01-01

    Adsorbents are important components in adsorption refrigeration. The diameter of an adsorbent can af-fect the heat and mass transfer of an adsorber. The effect of particle diameter on effective thermal conductivity was investigated. The heat transfer coefficient of the refrigerant and the void rate of the adsorbent layer can also affect the effective thermal conductivity of adsorbents. The performance of mass transfer in the adsorber is better when pressure drop decreases. Pressure drop decreases with increasing permeability. The permeability of the adsorbent layer can be improved with increasing adsorbent diameter. The effect of adsorbent diameter on refrigeration output power was experimentally studied. Output power initially increases and then decreases with increasing diameter under different cycle time conditions. Output power increases with decreasing cycle time under similar diameters.

  4. Refrigerator-freezer energy testing with alternative refrigerants

    Science.gov (United States)

    Vineyard, E. A.; Sand, J. R.; Miller, W. A.

    1989-07-01

    As a result of the Montreal Protocol that limits the production of ozone-depleting refrigerants, manufacturers are searching for alternatives to replace the R12 that is presently used in residential refrigerator-freezers. Before an alternative can be selected, several issues must be resolved. Among these are energy impacts, system compatibility, cost, and availability. In an effort to determine the energy impacts of some of the alternatives, energy consumption tests were performed in accordance with section 8 of the Association of Home Appliance Manufacturers (AHAM) standard for household refrigerators and household freezers. The results are presented for an 18 cubic foot (0.51 cubic meter), top-mount refrigerator-freezer with a static condenser using the following refrigerants: R12, R500, R12/Dimethyl-ether (DME), R22/R142b, and R134a. Conclusions from the AHAM test are that R500 and R12 /DME have a reduced energy consumption relative to R12 when replaced in the test unit with no modifications to the refrigeration system. Run times were slightly lower than R12 for both refrigerants indicating a higher capacity. While the R134a and R22/R142b results were less promising, changes to the refrigeration system, such as a different capillary tube or compressor, may improve performance.

  5. Experimental methods used to determine the amount of H{sub 2}O in the CO{sub 2} refrigeration cycle; Experimentelle Methoden zur Bestimmung des H{sub 2}O-Gehaltes im CO{sub 2}-Kaeltekreislauf

    Energy Technology Data Exchange (ETDEWEB)

    Petereit, Anna Katharina; Eggers, Rudolf [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Arbeitsgruppe Waerme- und Stofftransport

    2012-07-01

    Water can be added to CO{sub 2} refrigeration circuits in the course of pressure testing of the system, in the course of the filling operation and also in the operation excess of the residual moisture content of the compressor oil. This water can be solved in CO{sub 2} as well as accumulate in certain parts of the system. This results in a deterioration of the operating performance. There are two forms of water separation to be differentiated: The separation as a liquid or as a solid phase (hydrate). In order to investigate the impact of water on the refrigeration process using CO{sub 2} as a refrigerant and on the refrigerating machine oils used in the process, it is therefore important to determine the water content in the process exactly. Therefore, various measuring devices for detecting the content of water dissolved in CO{sub 2} and the content of the discharged water are installed in a CO{sub 2} pilot plant. The determination of the water content in CO{sub 2} is performed by means of a fiber-optic moisture sensor which is integrated in the system between the gas cooler and the throttle. The total water content is determined via a lot of bypass piping systems at different positions in the circuit. Due to this structure, representative sample volumes can be withdrawn while the system is still running. These probe volumes can be analyzed by means of the Karl-Fischer method. The hydrate formation is investigated by means of two optical cells which are installed behind the throttle. Based on these measurement devices, an analysis of the changed operating behavior of the CO{sub 2} refrigeration plant and a localization of possible water sinks in the circuit are performed.

  6. 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.)

  7. Computer-Aided Chemical Product Design Framework: Design of High Performance and Environmentally Friendly Refrigerants

    DEFF Research Database (Denmark)

    Cignitti, Stefano; Zhang, Lei; Gani, Rafiqul

    a driving force for the industry to continuously seek novel refrigerants as current refrigerants risk phasing out due to environmental regulations. This trend has been seen since the Kyoto Protocol in 1997 and recently from the EU regulations from 2014, which will restrict the use of some known refrigerants...... properties and needs should carefully be selected for a given heat pump cycle to ensure that an optimum refrigerant is found? How can cycle performance and environmental criteria be integrated at the product design stage and not in post-design analysis? Computer-aided product design methods enable...... the possibility of designing novel molecules, mixtures and blends, such as refrigerants through a systematic framework (Cignitti et al., 2015; Yunus et al., 2014). In this presentation a computer-aided framework is presented for chemical product design through mathematical optimization. Here, molecules, mixtures...

  8. False-Positive Clostridium difficile in Negative-Control Reactions Peak and Then Decrease with Repetitive Refrigeration of Immunoassay.

    Science.gov (United States)

    Rodriguez-Palacios, Alexander; Stämpfli, Henry R; Chang, Yung-Fu

    2014-01-01

    Aberrant false-positive reactions in negative-controls during ELISA testing for Clostridium difficile indicated the potential for false-diagnoses. Experiments with 96-well products showed a maximum peak of false-positive immunoassay reactions with the provided negative-control reagents after 5 refrigeration-to-room temperature cycles (P refrigeration cycles. Because repetitive refrigeration causes a peak of false-positives, the use of single negative-controls per ELISA run might be insufficient to monitor aberrant preanalytical false-positives if immunoassays are subject to repetitive refrigeration.

  9. Energy optimisation of domestic refrigerators

    DEFF Research Database (Denmark)

    Jakobsen, Arne; Rasmussen, Bjarne D.

    1998-01-01

    This paper describes the main results of a research project with the objective of reducing the energy consumption of domestic refrigerators by increasing the efficiency of the refrigeration system. The improvement of the system efficiency was to be obtained by:1) Introducing continuous operation...

  10. Coherent Hole-burning, Mollow Absorption Effect, and Four-wave Mixing in Cycling Transition Fe=0(←→)Fg=1 Subject to a Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    古英; 孙庆青; 龚旗煌

    2004-01-01

    @@ We investigate the quantum coherence effects of a cycling transition Fe=0(←→)Fg=1, which is saturated and probed by the circular polarized fields, and is subject to a linearly polarized field and a magnetic field.Saturation field is applied in the case of the maximum coherence between the drive Rabi frequency and magnetic field, corresponding to the electromagnetically induced absorption (EIA) with negative dispersion found by Gu et al.In a small saturation Rabi frequency, the holes are burned in two Autler-Towns peaks outside two symmetric electromagnetically induced transparency (EIT) windows due to the two-photon resonance.When the saturation Rabi frequency is comparable with the drive Rabi frequency, the holes caused by the coherent population oscillation appear in the EIA spectrum.Continuing to increase the saturation Rabi frequency, we observe several emission peaks due to the Mollow absorption effects.Simultaneously, four-wave mixing (FWM) effects in this process are discussed.In the picture of dressed states, we explain the multi-peaks of quantum efficiency of FWM in terms of the multi-photon resonance conditions.We also find a good agreement between the absorption peaks and the FMW peaks.Finally, whenever EIA, EIT, or Mollow absorption happens, the dispersion at the pump-probe detuning center is kept to be negative with increasing the saturation Rabi frequency.It means that this point is suitable to perform the superluminal light propagation experiments.

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

    KAUST Repository

    Myat, Aung

    2011-10-01

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

  12. Study on wave rotor refrigerators

    Institute of Scientific and Technical Information of China (English)

    Yuqiang DAI; Dapeng HU; Meixia DING

    2009-01-01

    As a novel generation of a rotational gas wave machine, the wave rotor refrigerator (WRR) is an unsteady flow device used for refrigeration, in whose passages pressured streams directly contact and exchange energy due to the movement of pressure waves. In this paper, the working mechanism and refrigeration principle are inves-tigated based on the one-dimensional unsteady flow theory.A basic limitation on main structural parameters and operating parameters is deduced and the wave diagram of WRR to guide designing is sketched. The main influential factors are studied through an experiment. In the DUT Gas Wave Refrigeration Studying and Development Center (GWRSDC) lab, the isentropic efficiency can now reach about 65%. The results show that the WRR is a feasible and promising technology in pressured gas refrigeration cases.

  13. 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.

  14. Progress in magnetic refrigeration and future challenges

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Pryds, Nini

    2014-01-01

    refrigerators have the potential for high efficiency. However, reported device COPs for laboratory devices are still well below commercially available vapor compression systems. In order to significantly improve AMR efficiency, several loss mechanisms must be reduced and other aspects of system design......Since a regenerative magnetic cooling cycle was first demonstrated in 1976, many developments have been made in the areas of system modeling, magnetocaloric materials and system design. Systems have gone from laboratory demonstrators using superconducting magnets to near commercial systems using...

  15. 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.

  16. Minimizing quality deteriorations of refrigerated foodstuffs as a side effect of defrosting

    DEFF Research Database (Denmark)

    Cai, Junping; Stoustrup, Jakob

    2008-01-01

    This paper proposes an optimization scheme for traditional refrigeration systems with hysteresis controllers and scheduled defrosts. It aims at minimizing the side effect of defrost cycles on the storage quality of refrigerated foodstuffs in supermarkets. By utilizing the thermal mass of air...... and products inside a display cabinet, this optimization scheme forces the compressor to work harder and cool down more prior to the scheduled defrosts, thus guaranteeing the product temperature after defrost cycles still to be within a controlled safe level....

  17. Minimizing quality deteriorations of refrigerated foodstuffs as a side effect of defrosting

    DEFF Research Database (Denmark)

    Cai, Junping; Stoustrup, Jakob

    2008-01-01

    This paper proposes an optimization scheme for traditional refrigeration systems with hysteresis controllers and scheduled defrosts. It aims at minimizing the side effect of defrost cycles on the storage quality of refrigerated foodstuffs in supermarkets. By utilizing the thermal mass of air...... and products inside a display cabinet, this optimization scheme forces the compressor to work harder and cool down more prior to the scheduled defrosts, thus guaranteeing the product temperature after defrost cycles still to be within a controlled safe level....

  18. Analyse of optimized cost of cycle refrigeration of ejector attended with solar energy using water and CO{sub 2} as fluid of work; Uma Analise de custo otimizado de ciclo refrigeracao de ejetor assistido com energia solar utilizando agua e CO{sub 2} como fluidos de trabalho

    Energy Technology Data Exchange (ETDEWEB)

    Colle, S.; Cardemil, J.; Vidal, H.; Escobar, R.

    2008-07-01

    The use of CO{sub 2} as working fluid in cooling cycles based on mechanical compression of vapour has two disadvantages. The first is that the critical temperature of CO{sub 2} is relatively low and the second is that the higher pressure of the cycle is exceedingly high, in comparison to the working fluids normally utilized in refrigeration. the conjugation of an ejector cycle using water as working fluid with a mechanical compression cycle using CO{sub 2} as working fluid is proposed in order to operate the CO{sub 2} cycle with lower pressure, with the advantage of increased coefficient of performance. One advantage of using CO{sub 2} and water is that these fluid are abundant in the environment. Another advantage is that these fluids are cheap and chemically stable, and therefore cause no effect in the ozone layer. The present work reports and economic analysis based on an analytical approach to optimize the collector area as well as the temperature of the inter cooler of the cycle. (Author)

  19. Aspects on modeled and the design of a system of refrigeration by absorption attended with solar energy; Aspectos sobre el modelado y diseno de un sistema de refrigeracion por absorcion asistido con energia solar

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Cascales, J. R.; Vera Garcia, F.; Cano Izquierdo, J. M.; Delgado Marin, J. P.; Martinez Sanchez, R.

    2008-07-01

    In this paper, we study the global modelling of an absorption system working with Br Li-H{sub 2}O. It satisfies the air-conditioning necessities of a classroom in an educational centre in Puerto Lumbreras. Murcia. This system utilises a set of solar collector to satisfy the thermal necessities of the vapour generator in the absorption system. For the dynamical simulation of the system we have used the TRNSYS software. The air-conditioned place has been modelled by using a TRNSYS module called PREBID. In this work, special attention is paid to the absorption equipment model developed by using neural networks which has been implemented in TRNSYS. The paper is closed drawing some conclusions. (Author)

  20. 磁制冷发展现状及趋势:Ⅱ磁制冷技术%DEVELOPMENT OF MAGNETIC REFRIGERATION.PART Ⅱ:MAGNETIC REFRIGERATION

    Institute of Scientific and Technical Information of China (English)

    陈远富; 陈云贵; 滕保华; 唐永柏; 付浩; 唐定骧; 涂铭旌

    2001-01-01

    The basic principle of magnetic refrigeration has been introduced.The difference between magnetic refrigeration and gas compressing refrigeration has been given and the four basic cycles of magnetic refrigeration have been summerized.Then the development of magnetic refrigerators,especially room temperature magnmetic refrigerator has been reviewed.The key technology of magnetic refrigeration has been analyzed.The potentioal market of magnetic refrigeration and the development trend have been provided.%简要介绍了磁制冷实现的原理,概括了磁制冷与气体压缩制冷的差异,比较了4种磁制冷循环的优缺点及适用场合,重点评述了室温温区磁制冷样机的研究进展,分析了磁制冷的关键技术,最后给出了磁制冷的潜在市场并展望了发展趋势。