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A Review on Technologies for the Use of CO2 as a Working Fluid in Refrigeration and Power Cycles
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作者 Orelien T. Boupda Hyacinthe D. Tessemo +3 位作者 Isidore B. Nkounda Fongang Francklin G. Nyami Frederic Lontsi Thomas Djiako 《Energy and Power Engineering》 2024年第6期217-256,共40页
The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its ther... The use of carbon dioxide as a working fluid has been the subject of extensive studies in recent years, particularly in the field of refrigeration where it is at the heart of research to replace CFC and HCFC. Its thermodynamic properties make it a fluid of choice in the efficient use of energy at low and medium temperatures in engine cycles. However, the performance of transcritical CO2 cycles weakens under high temperature and pressure conditions, especially in refrigeration systems;On the other hand, this disadvantage becomes rather interesting in engine cycles where CO2 can be used as an alternative to the organic working fluid in small and medium-sized electrical systems for low quality or waste heat sources. In order to improve the performance of systems operating with CO2 in the field of refrigeration and electricity production, research has made it possible to develop several concepts, of which this article deals with a review of the state of the art, followed by analyzes in-depth and critical of the various developments to the most recent modifications in these fields. Detailed discussions on the performance and technical characteristics of the different evolutions are also highlighted as well as the factors affecting the overall performance of the systems studied. Finally, perspectives on the future development of the use of CO2 in these different cycles are presented. 展开更多
关键词 refrigeration Cycle Power Cycle System Performance Transcritical CO2 Cycles Working Fluid
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Experimental Analysis of the Performances of Unit Refrigeration Systems Based on Parallel Compressors with Consideration of the Volumetric and Isentropic Efficiency 被引量:8
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作者 Daoming Shen Chao Gui +1 位作者 Jinhong Xia Songtao Xue 《Fluid Dynamics & Materials Processing》 EI 2020年第3期489-500,共12页
The performances of a refrigeration unit relying on compressors working in parallel have been investigated considering the influence of the compressor volumetric efficiency and isentropic efficiency on the compression... The performances of a refrigeration unit relying on compressors working in parallel have been investigated considering the influence of the compressor volumetric efficiency and isentropic efficiency on the compression ratio.Moreover,the following influential factors have been taken into account:evaporation temperature,condensation temperature and compressor suction-exhaust pressure ratio for different opening conditions of the compressor.The following quantities have been selected as the unit performance measurement indicators:refrigeration capacity,energy efficiency ratio(COP),compressor power consumption,and refrigerant flow rate.The experimental results indicate that the system refrigeration capacity and COP decrease with a decrease in evaporation temperature,increase of condensation temperature,and increase in pressure ratio.The refrigerant flow rate increases with the increase in evaporation temperature,decrease in condensing temperature and increase in pressure ratio.The compressor power consumption increases with the increase in condensing temperature and increase in pressure ratio,but is not significantly affected by the evaporation temperature. 展开更多
关键词 Parallel compressor unit evaporation temperature condensation temperature pressure ratio refrigeration capacity energy efficiency ratio(COP)
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Effect of an Internal Heat Exchanger on the Performances of a Double Evaporator Ejector Refrigeration Cycle
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作者 Rachedi Khadraoui Latra Boumaraf Philippe Haberschill 《Fluid Dynamics & Materials Processing》 EI 2023年第5期1115-1128,共14页
A theoretical investigation is presented about a double evaporator ejector refrigeration cycle(DEERC).Special attention is paid to take into account the influence of the sub-cooling and superheating effects induced by... A theoretical investigation is presented about a double evaporator ejector refrigeration cycle(DEERC).Special attention is paid to take into account the influence of the sub-cooling and superheating effects induced by an internal heat exchanger(IHX).The ejector is introduced into the baseline cycle in order to mitigate the throttling process losses and increase the compressor suction pressure.Moreover,the IHX has the structure of a concentric counter-flow type heat exchanger and is intentionally used to ensure that the fluid at the compressor inlet is vapor.To assess accurately the influence of the IHX on the DEERC performance,a mathematical model is derived in the frame of the dominant one-dimensional theory for ejectors.The model also accounts for the friction effect in the ejector mixing section.The equations of this model are solved using an Engineering Equation Solver(EES)for different fluids.These are:R134a as baseline fluid and other environment friendly refrigerants used for comparison,namely,R1234yf,R1234ze,R600,R600a,R290,R717 and R1270.The simulation results show that the DEERC with an IHX can achieve COP(the coefficient of performance)improvements from 5.2 until 10%. 展开更多
关键词 refrigeration cycle double evaporator EJECTOR IHX performance improvement environment-friendlyrefrigerants
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Performance Analysis of a Solar Continuous Adsorption Refrigeration System
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作者 Kolthoum Missaoui Nader Frikha +2 位作者 Abdelhamid Kheiri Slimane Gabsi Mohammed El Ganaoui 《Fluid Dynamics & Materials Processing》 EI 2023年第4期1067-1081,共15页
A study is conducted on the performances of a solar powered continuous-adsorption refrigerator considering two particular days as references cases,namely,the summer solstice(June 21st)and the autumn equinox(September ... A study is conducted on the performances of a solar powered continuous-adsorption refrigerator considering two particular days as references cases,namely,the summer solstice(June 21st)and the autumn equinox(September 21st).The cooling capacity,system performance coefficient and the daily rate of available cooling energy are assessed.The main goal is to compare the performances of a solar adsorption chiller equipped with a hot water tank(HWT)with an equivalent system relying on solar collectors with no heat storage module.The daily cooling rates for the solar refrigerator are found to be 102.4 kWh and 74.3 kWh,respectively,on June 21st and on September 21st,using a total collector’s area of 43.47 m2.The corresponding values for the adsorption chiller equipped with a hot water tank of 2 m3(and using a total collector’s area of 72.45 m2),are 127.1 kWh and 106.13 kWh,respectively. 展开更多
关键词 Solar continuous adsorption refrigerator dynamic energetic study system performance hot water tank CPC collector thorough system variable heat source
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Studies on Benign Working Pairs for Adsorption Refrigeration 被引量:1
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作者 崔群 陈海军 姚虎卿 《Journal of Southeast University(English Edition)》 EI CAS 2002年第3期283-288,共6页
Water and ethanol were selected as refrigerants, 13x molecular sieve, silica gel, activated carbon and adsorbents NA and NB prepared by authors were selected as adsorbents, and the performance of adsorption working pa... Water and ethanol were selected as refrigerants, 13x molecular sieve, silica gel, activated carbon and adsorbents NA and NB prepared by authors were selected as adsorbents, and the performance of adsorption working pairs in adsorption refrigeration system was studied. The adsorption isotherms of adsorbents (NA and NB) were obtained by high vacuum gravimetric method. Desorption properties of adsorbents were analyzed and compared by thermal analysis method. The performance parameters of adsorption refrigerat... 展开更多
关键词 adsorption refrigeration working pairs ISOTHERM refrigeration volume
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Aqueous ammonia solution cooling absorption refrigeration driven by fishing boat diesel exhaust heat 被引量:5
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作者 陈亚平 林陈敏 田莹 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期333-338,共6页
A solution cooling absorption(SCA)approach is proposed to modify the aqueous ammonia absorption refrigerat-ion cycle using the strong solution from the absorber to cool the forepart of the absorption in the cycle fo... A solution cooling absorption(SCA)approach is proposed to modify the aqueous ammonia absorption refrigerat-ion cycle using the strong solution from the absorber to cool the forepart of the absorption in the cycle for reclaiming some portion of absorption heat.As a consequence of raised temperature at the inlet,the strong solution partially boils at the outlet of the solution heat exchanger,and diminishes the thermal heat consumption of the heat source.The calculation results show that the coefficient of performance(COP)of this modified cycle is about 28.3% higher than that of the traditional cycle under typical conditions;while the required heat transfer area of the total heat exchangers of the cycle is somewhat less than that of the traditional one.The capacity of refrigeration with the new absorption cycle is more than doubled in contrast to the adsorption scheme with an identical configuration.It is sufficient to supply a fishing boat the chilling capacity for preservation of fishing products with the modified cycle chiller driven by its diesel engine exhaust. 展开更多
关键词 aqueous ammonia absorption refrigeration solution cooling absorption waste heat recovery heat and mass transfer coefficient of performance
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OPTIMAL PERFORMANCE OF THERMOELECTRIC REFRIGERATION SYSTEM USING ENTROPY GENERATION MINIMIZATION METHOD 被引量:2
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作者 曹业玲 夏文庆 余莉 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第4期339-343,共5页
With the entropy generation minimization (EGM) method, the thermodynamical performance optimization in a thermoelectric refrigeration system is studied. The optimization is affected by the irreversibility of heat tr... With the entropy generation minimization (EGM) method, the thermodynamical performance optimization in a thermoelectric refrigeration system is studied. The optimization is affected by the irreversibility of heat transfer caused by finite temperature differences, the heat leak between external heat reservoirs and the internal dissipation of working fluids. EGM is taken as an objective function for the optimization. The objective function and design parameters are obtained. Optimal performance curves are presented by thermal and electronic parameters. Effects of these parameters on general and optimal performances are investigated. Results are helpful in determining optimal design conditions in real thermoelectric refrigeration systems. 展开更多
关键词 thermoelectric refrigeration system entropy generation minimization finite-time thermodynamics
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Performance analysis of aircraft low-power thermoelectric refrigeration system 被引量:2
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作者 张兴娟 王羽白 《Journal of Southeast University(English Edition)》 EI CAS 2010年第2期372-374,共3页
An optimal design method for an aircraft low-power thermoelectric refrigeration system(TRS)is proposed using an existing experimental model as the research platform under given aircraft flight conditions.The variati... An optimal design method for an aircraft low-power thermoelectric refrigeration system(TRS)is proposed using an existing experimental model as the research platform under given aircraft flight conditions.The variation curves of the cooling capacities and the refrigeration coefficients of the system running at three flight altitudes are investigated.The performance of the system is evaluated by the minimum-entropy-generation method and the performance penalty is also calculated.The power variation curves of the cooling system are obtained by an electric power experiment.The peak values of these curves are less than the maximal electric power supply of airborne equipment,proving that the use of the low-power TRS for airborne equipment is feasible.The COP,cooling capacity and entropy generation of the system are relative to the flight altitude and the current of the TRS.Through the analyses of these data,the optimal values of the COP are obtained,and the optimization measures are proposed to maximize the use of the advantages of the TRS. 展开更多
关键词 thermoelectric refrigeration entropy generation anal-ysis aircraft cooling system performance penalty
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Magnetic and magnetocaloric effect of Er_(20)Ho_(20)Dy_(20)Cu_(20)Ni_(20)high-entropy metallic glass
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作者 于世霖 田路 +4 位作者 王俊峰 赵新国 李达 莫兆军 李昺 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期602-606,共5页
Er_(20)Ho_(20)Dy_(20)Cu_(20)Ni_(20)high-entropy metallic glass exhibited excellent magnetic refrigeration material with a wide temperature range and high refrigeration capacity(RC)was reported.Er_(20)Ho_(20)Dy_(20)Cu_... Er_(20)Ho_(20)Dy_(20)Cu_(20)Ni_(20)high-entropy metallic glass exhibited excellent magnetic refrigeration material with a wide temperature range and high refrigeration capacity(RC)was reported.Er_(20)Ho_(20)Dy_(20)Cu_(20)Ni_(20)high-entropy metallic glass was observed with typical spin glass behavior around 15.5 K.In addition,we find that the magnetic entropy change(-△S_(M))originates from the sample undergoing a ferromagnetic(FM)to paramagnetic(PM)transition around 20 K.Under a field change from 0 T to 7 T,the value of maximum magnetic entropy change(-△S_(M)^(max))reaches 12.5 J/kg·K,and the corresponding value of RC reaches 487.7 J/kg in the temperature range from 6 K to 60 K.The large RC and wide temperature range make the Er_(20)Ho_(20)Dy_(20)Cu_(20)Ni_(20)high-entropy metallic glass be a promising material for application in magnetic refrigerators. 展开更多
关键词 magnetic materials magnetocaloric effect high-entropy metallic glass magnetic refrigeration large refrigeration capacity
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Effect of cerium ion(Ⅲ) on corrosion resistance of organic-inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment
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作者 肖围 缪畅 +1 位作者 黄雄 满瑞林 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第11期3847-3854,共8页
Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed ... Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements. 展开更多
关键词 aluminum-tube organic-inorganic hybrid coating corrosion resistance cerium ion(Ⅲ) refrigeration equipment
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APPLICATION POSSIBILITY OF BINARY NONAZEOTROPIC REFRIGERANT IN JET REFRIGERATION *
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作者 张于峰 张利民 +1 位作者 李灿华 孙萍 《Transactions of Tianjin University》 EI CAS 1998年第1期26-30,共5页
This paper analyzes the possibility of applying binary nonazeotropic refrigerants in the jet refrigeration cycle. The thermodynamic cycle performance of two kinds of working pairs (R30/R142b, R30/R124) are calculated ... This paper analyzes the possibility of applying binary nonazeotropic refrigerants in the jet refrigeration cycle. The thermodynamic cycle performance of two kinds of working pairs (R30/R142b, R30/R124) are calculated using the EOS of PR equation of state, and the results are discussed. The theoretical calculations indicate that refrigerating quality can be improved if the binary mixtures evaporate just in the low temperature region. The character of the rejecter to compress two phase medium supports the possibility of this kind of cycle. 展开更多
关键词 jet refrigeration evaporating in low temperature region vapour liquid two phase compression binary nonazeotropic refrigerant
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Development of 400-μW cryogen-free dilution refrigerators for quantum experiments
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作者 关翔 樊洁 +2 位作者 边勇波 程智刚 姬忠庆 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第7期28-35,共8页
We have successfully developed cryogen-free dilution refrigerators with medium cooling power that can be applied to quantum experiments. Breakthroughs have been made in some key technologies and components of heat swi... We have successfully developed cryogen-free dilution refrigerators with medium cooling power that can be applied to quantum experiments. Breakthroughs have been made in some key technologies and components of heat switches and dilution units. Our prototype has been running continuously and stably for more than 100 hours below 10 m K, with a minimum temperature of 7.6 m K and a cooling power of 450 μW at 100 m K. At the same time, we have also made progress in the application of dilution refrigerators, such as quantum computing, low-temperature detector, and magnet integration. These indicators and test results indicate good prospects for application in physics, astronomy, and quantum information. 展开更多
关键词 cryogen-free dilution refrigerator quantum computing low-temperature detector superconducting magnet
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Optimization performance of quantum endoreversible Otto machines with dual-squeezed reservoirs
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作者 Haoguang Liu 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期198-204,共7页
We consider a quantum endoreversible Otto engine cycle and its inverse operation-Otto refrigeration cycle,employing two-level systems as the working substance and operating in dual-squeezed reservoirs.We demonstrate t... We consider a quantum endoreversible Otto engine cycle and its inverse operation-Otto refrigeration cycle,employing two-level systems as the working substance and operating in dual-squeezed reservoirs.We demonstrate that the efficiency of heat engines at maximum work output and the coefficient of performance for refrigerators at the maximum c criterion will degenerate toη-=η_(C)/(2-η_(C))andε-=(√9+8ε_(C)-3)/2 when symmetric squeezing is satisfied,respectively.We also investigated the influences of squeezing degree on the performance optimization of quantum Otto heat engines at the maximum work output and refrigerators at the maximum X criterion.These analytical results show that the efficiency of heat engines at maximum work output and the coefficient of performance for refrigerators at the maximum X criterion can be improved,reduced or even inhibited in asymmetric squeezing.Furthermore,we also find that the efficiency of quantum Otto heat engines at maximum work output is lower than that obtained from the Otto heat engines based on a single harmonic oscillator system.However,the coefficient of performance of the corresponding refrigerator is higher. 展开更多
关键词 quantum Otto heat engine quantum Otto refrigerator optimization performance dual-squeezed reservoirs
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Intermodal Competition: Cargo Airships versus Long-Haul Trucking for Perishable Commodities
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作者 Barry Everett Prentice 《Journal of Transportation Technologies》 2024年第2期195-211,共17页
Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne... Intermodal competition changes with changes in technology, economics, and environmental concerns. Trucks and airships are generally considered not to be competitors, but this depends on the distance of haul. The tonne-kilometer cost of trucking rises much more quickly with distance than it does the cost of a cargo airship. At some distance, the two modes are direct substitutes. The costs of the Mexico-Canada refrigerated truck supply chain are compared with the costs of a 100t-lift, electrically-powered airship. The flight characteristics of the Hindenburg Zeppelin are used as a model for a modern cargo airship. The supply chain cost of trucking tomatoes is used to test the theorical proposition. The cost difference works out to about US10¢/kg (5¢/lb) advantage for trucking Mexican tomatoes to Canada. However, this cost disadvantage of the airship could be made up by their vibrationless ride, better air circulation and one-day service versus four days by truck. This alternative form of transportation could have a positive impact on worldwide north-south distribution of food. Airships can overcome trade barriers and distance to open new markets for perishable food exports. In addition, they would reduce the carbon emissions of transport. Canada imports 160,000 refrigerated truckloads of fruits and vegetables by from the southern US and Mexico. With an average driving distance of 3,000 km, these trucks emit 606,000 MT of CO<sub>2</sub> annually. Airships powered by hydrogen fuel cells would have zero-carbon emissions. Markets are not yet incorporating the environmental advantage of airships in any freight comparison, but inevitably this will be important. 展开更多
关键词 AIRSHIP Refrigerated Trucks Mexico Tomatoes Carbon-emissions Perishables
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Cooling High Power Dissipating Artificial Intelligence (AI) Chips Using Refrigerant
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作者 Waheeb Mukatash Hussameddine Kabbani +4 位作者 Jochem Marc Massalt Matthew Moscoso Merari Mejia Robles Tyler Yang Charlie Nino 《Journal of Electronics Cooling and Thermal Control》 2024年第2期35-49,共15页
High power dissipating artificial intelligence (AI) chips require significant cooling to operate at maximum performance. Current trends regarding the integration of AI, as well as the power/cooling demands of high-per... High power dissipating artificial intelligence (AI) chips require significant cooling to operate at maximum performance. Current trends regarding the integration of AI, as well as the power/cooling demands of high-performing server systems pose an immense thermal challenge for cooling. The use of refrigerants as a direct-to-chip cooling method is investigated as a potential cooling solution for cooling AI chips. Using a vapor compression refrigeration system (VCRS), the coolant temperature will be sub-ambient thereby increasing the total cooling capacity. Coupled with the implementation of a direct-to-chip boiler, using refrigerants to cool AI server systems can materialize as a potential solution for current AI server cooling demands. In this study, a comparison of 8 different refrigerants: R-134a, R-153a, R-717, R-508B, R-22, R-12, R-410a, and R-1234yf is analyzed for optimal performance. A control theoretical VCRS model is created to assess variable refrigerants under the same operational conditions. From this model, the coefficient of performance (COP), required mass flow rate of refrigerant, work required by the compressor, and overall heat transfer coefficient is determined for all 8 refrigerants. Lastly, a comprehensive analysis is provided to determine the most optimal refrigerants for cooling applications. R-717, commonly known as Ammonia, was found to have the highest COP value thus proving to be the optimal refrigerant for cooling AI chips and high-performing server applications. 展开更多
关键词 Artificial Intelligence Thermal Control Server Systems Vapor Compression refrigeration Cycle Server Cooling
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Performance analysis of ammonia-water absorption/compression combined refrigeration cycle 被引量:1
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作者 鲍帅阳 杜垲 +2 位作者 蔡星辰 牛晓峰 武云龙 《Journal of Southeast University(English Edition)》 EI CAS 2014年第1期60-67,共8页
In view of different compressor adding ways in the ammonia-water absorption/compression combined refrigeration AWA /CCR cycle combining the Schulz state equation of the ammonia-water solution the theoretical analysis ... In view of different compressor adding ways in the ammonia-water absorption/compression combined refrigeration AWA /CCR cycle combining the Schulz state equation of the ammonia-water solution the theoretical analysis and calculations on two combination ways by adding the compressor in the high-pressure area and in the low-pressure area are conducted respectively.The effects of several factors including the evaporation temperature Te heat-source temperature Th as well as the cooling water temperature Tw on the equivalent heat consumption in compression qCW heat consumption in absorption qG and the system coefficient of performance COP are analyzed under the two combination configurations.The results show that the effect of the equivalent heat consumption in compression on the COP is less than that of the heat consumption in absorption.Besides the compressor set in the high-pressure area uses more energy than that in the low-pressure area. Moreover the compressor in the low-pressure area is superior to that in the high-pressure area with respect to the COP. Under the given intermediate pressure there is an optimum heat-source temperature corresponding to the maximum COP of the AWA/CCR cycle. 展开更多
关键词 AMMONIA-WATER ABSORPTION compression refrigeration combined refrigeration cycle coefficient of performance COP
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Rare Earths and Magnetic Refrigeration 被引量:20
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作者 Karl A Gschneidner Vitalij K Pecharsky 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第6期641-647,共7页
Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrige... Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed. 展开更多
关键词 magnetic refrigeration magnetocaloric effect GADOLINIUM Gd5 Si1- x Gex 4 La Fe 13 - x Six Hy Nd2 Fe14 B permanent magnets active magnetic regenerator cycle rare earths
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Mixed refrigerant composition shift due to throttle valves opening in auto cascade refrigeration system 被引量:5
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作者 许雄文 刘金平 曹乐 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第1期199-204,共6页
Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition of mixed refrigerant has a great effect on the performance of the system. Based on the assumption of ... Auto cascade refrigeration(ACR) cycle with phase separators is widely used in the cryogenic system. The composition 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 concentration 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. 展开更多
关键词 Auto cascade refrigeration Composition shift THROTTLE
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Experimental Study of Air Conditioning Unit of Evaporative Cooling Assisted Mechanical Refrigeration 被引量:3
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作者 HUANG Xiang,XU Fang-cheng,WU Jun-mei(Xi’an polytechnic University,Xi’an,Shaanxi 710048,China) 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2009年第S1期106-110,共5页
The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analy... The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was conducted and analyzed.The test shows that making full use of the evaporative cooling "free cooling" in Spring and Autumn seasons can fully meet the requirements of air-conditioned comfort through the switch of the function in different seasons.Taking into account the evaporative cooling fan and pump energy consumption,compared with the traditional mechanical refrigeration system,more than 80 percent of energy can be saved,and the energy efficiency ratio of the Unit(EER)is as high as 7.63.Using the two stages of indirect evaporative cooling to pre-cool the new wind in summer,under the conditions of the same air supply temperature requirements,0.83 kg/s chilled water saved can be equivalent to the traditional mechanical refrigeration system,and when the new wind ratio up to 50 percent,more than 10 percent load was reduced in mechanical refrigeration system.The overall EER increased about 35 percent. 展开更多
关键词 EVAPORATIVE COOLING mechanical refrigeration AIR-CONDITIONING unit EER
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Thermodynamic optimization for a quantum thermoacoustic refrigeration micro-cycle 被引量:3
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作者 E Qing WU Feng +1 位作者 CHEN Lin-gen QIU Yi-nan 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第9期2754-2762,共9页
A model of quantum thermoacoustic refrigeration micro-cycle(QTARMC)is established in which heat leakage is considered.A single particle contained in a one-dimensional harmonic potential well is studied,and the system ... A model of quantum thermoacoustic refrigeration micro-cycle(QTARMC)is established in which heat leakage is considered.A single particle contained in a one-dimensional harmonic potential well is studied,and the system consists of countless replicas.Each particle is confined in its own potential well,whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions.Based on the Schrodinger equation,the expressions of coefficient of performance(COP)and cooling rate for the refrigerator are obtained.Effects of heat leakage on the optimal performance are discussed.The optimal performance region of the refrigeration cycle is obtained by the using ofΩobjective function.The results obtained can enrich the thermoacoustic theory and expand the application of quantum thermodynamics. 展开更多
关键词 thermoacoustic refrigeration quantum mechanics thermal phonon performance optimization finite time thermodynamics
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