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Journal of Materials Science and Chemical Engineering 2020年第11期8卷 33-42页

作者： Atsuhiro Ichinose Kazuki Kuwata Takehiro Esaki Takayuki Matsuda Noriyuki Kobayashi Nagoya University Furo-cho Chikusa-ku Nagoya Aichi Japan

We herein evaluate the use of a chemical heat pump (CHP) for upgrading waste heat. CaCl2 was used in the system of CHP. We evaluated the heat storage and heat releasing of CHP, and confirmed the practicality from the experimental results. The reactor module employed was an aluminum plate-tube heat exchanger with corrugated fins, and the CaCl2 powder was in the form of a packed bed. Heat storage operation and heat dissipation operation are performed at the same time and supplied to the heat demand destination. At this time, an environmental heat source can be used during the heat radiation operation, and the heat output can release more heat than the heat input during heat storage. The heat discharging and charging characteristics of the reactor module were evaluated experimentally. The coefficient of performance (COP) was calculated for the heat upgrading cycle, and the heat output in the system was determined. A COP of 1.42 and output of 650 W/L, based on the heat exchanger volume, were obtained using a 600 s change time for the heat pump.

关键词： Chemical Heat Pump CaCl2/H2O Hydration Reaction Heat Pump Cycle coefficient of performance

Analysis of performance and optimum configuration of two-stage semiconductor thermoelectric module

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Chinese Physics B 2008年第4期17卷 1349-1354页

作者：李开振梁瑞生魏正军 School of Information and Photoelectric Science and Technology South China Normal University

In this paper, the theoretical analysis and simulating calculation were conducted for a basic two-stage semiconductor thermoelectric module, which contains one thermocouple in the second stage and several thermocouples in the first stage. The study focused on the configuration of the two-stage semiconductor thermoelectric cooler, especially investigating the influences of some parameters, such as the current I1 of the first stage, the area A1 of every thermocouple and the number n of thermocouples in the first stage, on the cooling performance of the module. The obtained results of analysis indicate that changing the current I1 of the first stage, the area A1 of thermocouples and the number n of thermocouples in the first stage can improve the cooling performance of the module. These results can be used to optimize the configuration of the two-stage semiconductor thermoelectric module and provide guides for the design and application of thermoelectric cooler.

关键词： thermocouples coefficient of performance cooling capacity

Exploring heating performance of gas engine heat pump with heat recovery

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Journal of Central South University 2016年第8期23卷 1931-1936页

作者：董付江刘凤国李先庭尤学一赵冬芳 School of Energy and Safety Engineering Tianjin Chengjian University School of Architecture Tsinghua University School of Environmental Science and Engineering Tianjin University

In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1400-2600 r/min）, ambient air temperature（2.4-17.8 ℃） and condenser water inlet temperature（30-50℃）. The results show that as engine speed increases from 1400 r/min to 2600 r/min, the total heating capacity and energy consumption increase by about 30% and 89%, respectively; while the heat pump coefficient of performance（COP） and system primary energy ratio（PER） decrease by 44% and 31%, respectively. With the increase of ambient air temperature from 2.4 ℃ to 17.8 ℃, the heat pump COP and system PER increase by 32% and 19%, respectively. Moreover, the heat pump COP and system PER decrease by 27% and 15%, respectively, when the condenser water inlet temperature changes from 30 ℃ to 50 ℃. So, it is obvious that the effect of engine speed on the performance is more significant than the effects of ambient air temperature and condenser water inlet temperature.

关键词： gas engine heat pump coefficient of performance primary energy ratio heating mode heat recovery

Thermodynamic Analysis of Liquefied Natural Gas(LNG)Production Cycle in APCI Process

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Journal of Thermal Science 2012年第6期21卷 564-571页

作者： Shahrooz Abbasi Nezhad Bezhan Shabani Majid Soleimani Department of Mechanical Engineering Langroud BranchIslamic Azad UniversityLangroudIran

The appropriate production of liquefied natural gas(LNG)with least consuming energy and maximum efficiency is quite *** this paper,LNG production cycle by means of APCI Process has been *** equilibrium equations and exergy equilibrium equations of each equipment in the APCI cycle were *** equipments are described using rigorous thermodynamics and no significant simplification is *** some operating parameters as key parameters,influences of these parameters on coefficient of performance(COP)and exergy efficiency of the cascading cycle were *** results indicate that COP and exergy efficiency will be improved with the increasing of the inlet pressure of MR(mixed refrigerant)compressors,the decreasing of the NG and MR after precooling process,outlet pressure of turbine,inlet temperature of MR compressor and NG temperature after cooling in main cryogenic heat exchanger(MCHE).The COP and exergy efficiency of the APCI cycle will be above 2% and 40%,respectively,after optimizing the key parameters.

关键词： LNG APCI process coefficient of performance Exergy efficiency

Solar thermoelectric generator and thermoelectric cooler performance:analysis and comparison using a different shape geometry

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Clean Energy 2023年第6期7卷 1233-1246页

作者： ALkhadher Khalil Smail Sahnoun Ahmed Elhassnaoui Said Yadir Abdellatif Obbadi Youssef Errami Laboratory:Electronics Instrumentation and EnergyFaculty of SciencesChouaib Doukkali UniversityEl JadidaMorocco National School of Applied Sciences—ENSABM Sultan Moulay Slimane University—Beni MallalMorocco Laboratory of Materials ProcessesEnvironment and QualityENSACadi Ayyad UniversitySafiMorocco

Thermoelectric devices are one of the technologies used either to generate electricity by applying a temperature difference using thermal energy or as a heating/cooling system by applying an electrical *** number of materials required to produce a product is an important factor in determining its *** costs associated with these materials,as well as their availability and quality,play a crucial role in price determination by *** this context,a method that employs a uniform volume distribution was *** approach enabled the analysis to focus on other variables,thereby promoting a more precise and relevant evaluation of overall *** on the finite element method,this study investigated the influence of geometric shape,including Rect-leg,Y-leg,Pin-leg and X-leg designs,on the performance of solar thermoelectric generators and thermoelectric *** study was conducted considering the same hot alumina junction surface that receives solar radiation;however,the ef-fective surface,which corresponded to the heat flow area and had a similar area near the exposed surface,varied depending on the chosen leg geometry,thus impacting the heat flux due to the variation in thermal *** the case of a solar thermoelectric generator,the Rect-leg model,having the same effective surface area,presented the lowest heat loss value resulting from convection and radiation in the heat spreader and the hot alumina *** the same conditions,the Y-leg showed the highest *** Rect-leg design generated,by using thermal and optical concentration,the highest output power of 0.028 and 0.054 W,and efficiency of 3.47%and 4.7%,respectively,whereas the Y-leg generated lower values of 0.006523 and 0.018744 W for power,and 2.83%and 2.71%for efficiency,*** the case of the thermoelectric coolers,the Y-leg generated the highest temperature difference between the hot and cold sides of 67.28 K at an electric current value

关键词： solar thermoelectric generators heat loss thermoelectric coolers coefficient of performance leg geometry same leg volume performance

performance optimization analysis of a thermoelectric refrigerator with two resonances

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Chinese Physics B 2011年第3期20卷 110-114页

作者：罗小光何济洲 Department of Physics Nanchang University

Based on electron transport theory, the performance of kx and kr filtered thermoelectric refrigerators with two resonances are studied in this paper. The performance characteristic curves between the cooling rate and the coefficient of performance are plotted by numerical calculation. It is shown that the maximum cooling rate of the thermoelectric refrigerator with two resonances increases but the maximum coefficient of performance decreases compared with those with one resonance. No matter which resonance mechanism is used （kx or kr filtered）, the cooling rate and the performance coefficient of the kr filtered refrigerator are much better than those of the kx filtered one.

关键词： thermoelectric refrigerator two resonances cooling rate coefficient of performance

Experimental Investigation on the performance of Heat Pump Operating with Copper and Alumina Nanofluids

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Computers, Materials & Continua 2021年第3期66卷 2843-2856页

作者： Faizan Ahmed Waqar Ahmed Khan Jamal Nayfeh Mechanical Engineering Department College of EngineeringPrince Mohammad Bin Fahd UniversityAl Khobar31952Saudi Arabia

In the present study,an attempt ismade to enhance the performance of heat pump by utilizing two types of nanofluids namely,copper and alumina *** nanofluids were employed around the evaporator coil of the heat *** nanofluids were used to enhance the heat input to the system by means of providing an external jacket around the evaporator *** the nanofluids were prepared in three volume fractions 1%,2%and 5%.Water was chosen as the base *** performance of the heat pump was assessed by calculating the coefficient of performance of the system when it was operated with and without nanofluid jacket.A significant enhancement in the coefficient of performance was noticed when copper and alumina nanofluids were employed in the ***,the coefficient of performance was found to have a direct relationship with the tested volume *** the highest volume fraction of 5%,the performance of the heat pump was found to enhance by 23%with alumina nanofluid,while for copper nanofluid,a very significant enhancement in performance by 72%was ***,utilizing of nanofluids in heat pumps can be very beneficial towards performance enhancement and the idea can also be extended to other thermal systems such as steam power plant,automobile radiator,industrial heat exchangers and refrigeration systems.

关键词： Nanoparticles copper nanofluid alumina nanofluid heat pump coefficient of performance

Analysis of influence of the length of ground heat exchangers on the operation characteristics and economy of ground source heat pumps

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Energy and Built Environment 2021年第2期2卷 127-136页

作者： Hongzhi Zhang Zongwei Han Lingyan Yang Jiawei Yuan Xinlu Cheng Mingzhen Ji Gui Li SEP Key Laboratory of Eco-Industry School of MetallurgyNortheastern UniversityShenyang 110819China China Academy of Building Research Beijing 100013China

A three-dimensional finite element dynamic simulation platform of the ground source heat pump system(GSHPS)is *** to the outlet temperature of ground heat exchangers(GHEs)required by the code in summer and winter,the calculated minimum buried depth of GHEs meeting the requirements is 60 m,when the number of borehole is *** using the established platform,the annual operation performance and cost of the GSHPS under different buried pipe depths are *** results show that the deeper the buried depth of GHEs is,the better the heat exchange effect of GHEs *** with the GHEs with 60 m buried depth,when the buried depth of GHEs is 65 m,70 m,75 m and 80 m,the average coefficient of performance(COP)of the unit increases by 4.1%,6.3%,7.7%and 8.2%in cooling period and 1.0%,1.6%,1.8%and 1.9%in heating period,*** the performance and initial investment of the GHSPS comprehensively,the optimal buried depth of GHEs is 60 ***,considering the performance the system and the total cost of the system running for 20 years comprehensively,the optimal buried depth of GHEs is 70 m.

关键词： Buried depth Dynamic simulation coefficient of performance Economic analysis

Frost-resistant embankments with a novel ground source heat pump system

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Research in Cold and Arid Regions 2024年第6期16卷 292-301页

作者： TianFei Hu Li Wang TengFei Wang TieCheng Sun TianFeng Li State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuangHebei 050043China School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuangHebei 050043China Key Laboratory of High-Speed Railway Engineering Southwest Jiaotong UniversityMinistry of EducationChengduSichuan 610031China

This study introduces a novel artificial heating technique aimed at addressing frost heave issues in embankments on frozen ground,offering a sustainable *** evaluations assessed various heating systems,including boilers,heat pumps,solar heaters,and electric heaters,focusing on their thermal performance and *** study subsequently designed and implemented a direct-expansion ground source heat pump(DX-GSHP)system as the primary heat source for embankment *** testing confirmed the DX-GSHP system's ability to maintain a heat-supply temperature above 40℃ and a heat-absorption temperature below -3.5℃,effectively extracting geothermal energy for transfer to the topsoil *** a demonstrated coefficient of performance(COP)of 3.49,the DX-GSHP system not only proves its energy efficiency but also suggests a potential role in reducing the strain on electricity supply *** of DX-GSHPs,with heating capacities ranging from 1.0 to 2.0 kW and spaced at intervals of 2.0-4.0 m,provides a rapid thermal response to frost heave in singletrack railway embankments,thereby potentially mitigating frost-induced damage in cold climate regions.

关键词： Frost heave Embankment Artificial heating Ground source heat pump coefficient of performance

Thermodynamic Comparison Analysis on CO_2 Transcritical Reverse Cycles with IHX or Expander

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Transactions of Tianjin University 2005年第2期11卷 110-114页

作者：管海清马一太杨俊兰李敏霞 School of Mechanical Engineering Tianjin University Tianjin 300072 China

To improve the coefficient of performance （COP） of CO2 transcritical reverse cycle and determine the most efficient cycle, comparison analysis on （single-and） two-stage CO2 transcritical cycles with internal heat exchanger （IHX） or expander is presented adopting the principle of thermodynamics. Results indicate that the COP of four cycles,namely single-stage compression with IHX （SI）, single-stage compression with expander （SE）, two-stage compression with IHX （TI） and two-stage compression with expander （TE）, can be ranged as TE>SE>TI>SI. It presents that adopting an expander to recover expansion power is the primary method to improve the COP of CO2 transcritical reverse cycle if the efficiency of the expander is up to a certain value. Under supposed operating condition, where the outlet temperature of gas cooler is 35 ℃ and the evaporating temperature is 5 ℃, the COP of TE cycle is about 4200 higher than that of SI cycle when the expander efficiency is 0.6 and the degree of superheat of IHX is 15 ℃. Therefore TE cycle is the most recommendatory one and it is better to adopt TE in those high-cooling capacity systems because its technology cost will be higher.

关键词： CO_2 transcritical reverse cycle internal heat exchanger expander coefficient of performance