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Chinese Journal of Chemical Engineering 2023年第3期55卷 20-33页

作者： Xinhao Li Qing Ye Jinlong Li Lingqiang Yan Xue Jian Licheng Xie Jianyu Zhang Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology School of Petrochemical EngineeringChangzhou UniversityChangzhou 213164China Changzhou University Huaide College Changzhou 213164China College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310000China

The conventional distillation is hard to accomplish the separation of acetonitrile/ethyl acetate/n-hexane mixture. Herein, a heterogeneous azeotropic distillation(HAD) without adding entrainer is proposed to separate ternary mixture. The proposed scheme is optimized via the simulated annealing algorithm and minimum total annual cost(TAC) is used as objective functions. To minimize energy consumption,heat pump is added on the basis of optimal heterogeneous azeotropic distillation and heat integration technology is used to further improve the energy recovery. The TAC, gas emission, energy consumption and exergy destruction are used to discuss the economy and environmental protection of processes.Among all the processes, the heat pump with higher preheating temperature(HPT) assisted HAD process by combining with heat integration(HAD-HPT-HI) has best performances on economic, environment,energy and exergy. Compared with conventional HAD process, the HAD-HPT-HI achieves the reductions of 52.17%, 68.86%, 65.87% and 65.46% on TAC, total energy consumption, gas emissions and exergy destruction, respectively.

关键词： Heterogeneous azeotropic distillation Energy-saving SA algorithm heat pump

Geometric heat pump:Controlling thermal transport with time-dependent modulations

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Frontiers of physics 2022年第1期17卷 155-168页

作者： Zi Wang Luqin Wang Jiangzhi Chen Chen Wang Jie Ren Center for Phononics and Thermal Energy Science China-EU Joint Lab on NanophononicsShanghai Key Laboratory of Special Artificial Microstructure Materials and TechnologySchool of Physics Science and EngineeringTongji UniversityShanghai200092China Department of Physics Zhejiang Normal UniversityJinhua321004China

The second law of thermodynamics dictates that heat simultaneously flows from the hot to cold bath on average. To go beyond this picture, a range of works in the past decade show that, other than the average dynamical heat flux determined by instantaneous thermal bias, a non-trivial flux contribution of intrinsic geometric origin is generally present in temporally driven systems. This additional heat flux provides a free lunch for the pumped heat and could even drive heat against the bias. We review here the emergence and development of this so called “geometric heat pump”, originating from the topological geometric phase effect, and cover various quantum and classical transport systems with different internal dynamics. The generalization from the adiabatic to the non-adiabatic regime and the application of control theory are also discussed. Then, we briefly discuss the symmetry restriction on the heat pump effect, such as duality, supersymmetry and time-reversal symmetry. Finally, we examine open problems concerning the geometric heat pump process and elucidate their prospective significance in devising thermal machines with high performance.

关键词： geometric phase heat pump stochastic heat transport non-adiabatic control

Preliminary design method for absorber pipe length of tunnel lining ground heat exchangers based on energy efficiency of heat pump

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Underground Space 2022年第6期7卷 1156-1174页

作者： Chenglin Li Guozhu Zhang Qi Zhang Yongli Xie Xiaohua Liu Shiding Cao Bin Wei Institute of Geotechnical Engineering Southeast UniversityNanjing 210096China School of Civil Engineering Southeast UniversityNanjing 210096China Shenzhen Transportation Design&Research Institute Co. LtdShenzhen 518003China

Many ongoing tunnel projects provide a favorable opportunity for the investigation and application of tunnel lining ground heat exchangers(GHEs).Tunnel lining GHEs can be connected to a heat pump to extract geothermal energy for heating and cooling buildings.Numerous studies have focused on the thermal performance of tunnel lining GHEs;however,the studies on the interaction between heat pumps and tunnel lining GHEs are relatively rare.In this study,a coupled heat transfer model of heat pumps and tunnel lining GHEs was proposed and then calibrated based on in situ test results.The model was used to evaluate the energy efficiency of a heat pump with tunnel lining GHEs under different conditions.The results show that the energy efficiency ratio(EER)increases exponentially with the absorber pipe length and thermal conductivity of the surrounding rock.The EER is governed by the convection heat transfer coefficient,which varies exponentially;meanwhile,the EER decreases approximately linearly with the annual average air temperature in the tunnel.Different types of heat pumps affect the EER significantly,and the EER of a Type-3 heat pump is higher than that of a Type-1 heat pump by 27.1%.Based on the aforementioned results,an empirical formula for the EER and absorber pipe length was established.Moreover,a preliminary design method for the absorber pipe length based on this empirical formula was developed.The method was employed to determine the appropriate absorber pipe length for the tunnel lining GHEs in the Shapu tunnel in Shenzhen,China.Finally,groups of absorber pipe layouts with a pipe spacing of 0.5 m,area of 135 m2,and length of 293.5 m were preliminarily determined.

关键词： Geothermal energy Tunnel lining GHEs Coupled heat transfer model heat pump Energy efficiency

Experimental Analyses of Moderately High-Temperature heat pump Systems with R245fa and R1233zd(E)

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Energy Engineering 2022年第6期119卷 2231-2242页

作者： Ting Chen Oh Kyung Kwon State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou310027China Clean Energy R&D Department Korea Institute of Industrial TechnologyCheonan31056Republic of Korea

With the limited production and use of R245fa,environmentally friendly refrigerant has attracted the attention of researchers.Due to the similar thermal characteristics,R1233zd(E)is considered to be an ideal substitute for R245fa in heat pump systems.In this study,the performance and economic analysis of heat pump systems with R245fa and R1233zd(E)as refrigerants are carried out.The results show that the total cost of R1233zd(E)system is more than 10%higher than that of R245fa system under the same heating load.With the increase of condensation temperature,the heating capacity of both systems decreases,and with the increase of evaporation temperature,the heating capacity increases.The variation trend of coefficient of performance(COP)of the two systems is similar to that of heating capacity.Under the same operating conditions,the COP of R1233zd(E)system is 19.2%higher than that of R245fa system,and the volumetric heat capacity of R1233zd(E)is 9.0%–13.9%lower than that of R245fa.The economic analysis results show that the investment cost of R1233zd(E)system is low under the same heat load.

关键词： heat pump R1233zd(E) R245fa performance comparison economic analysis

Performance testing of a heat pump system with auxiliary hot water under different ambient temperatures

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Energy and Built Environment

Energy and Built Environment 2022年第3期3卷 316-326页

作者： Xuejuan Li Yunfeng Wang Ming Li Mengxiao Hang Wenkui Zhao Decheng Kong Gaofei Yin Solar Energy Research Institute Yunnan Normal UniversityKunming 650500China Key Laboratory of Solar heating and Cooling Technology of Yunnan Provincial Universities Kunming 650500China

In recent decades,solar collector and heat pump combinations have been widely applied to supply heat and hot water,such as in heat supply and power generation for domestic and commercial buildings and relevant applications in the manufacturing and agricultural industries.However,the solar-assisted heat pumps already in extensive use may undergo system performance deterioration in a cold environment.To solve this problem,we designed a heat pump system assisted with hot water where a water medium was used to store energy to assist the operation of the heat pump at low temperatures.Three factors were comprehensively considered:the opening degree of the electronic expansion valve,the temperature of the low-temperature heat source,and the auxiliary hot water temperature.Crossover experiments were designed with three levels for each factor,and 36 groups of experiments were carried out.The results showed that as the auxiliary hot water temperature increased,the heating capacity and the coefficient of performance also increased.Thus,the overall working efficiency of the system improved.According to the orthogonal test,the most important influencing factor of system performance was the auxiliary hot water temperature,followed by the ambient temperature and opening degree of the electronic expansion valve.These results fully demonstrated that the addition of auxiliary hot water could dramatically improve system performance.In addition,optimization of the opening degree of the electronic expansion valve produced different results,indicating that the optimal value ranged from 50%−75%.

关键词： heat pump Energy reservation Auxiliary System performance

The role of heat pump in heating decarbonization for China carbon neutrality

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碳中和(英文)

碳中和(英文) 2022年第1期1卷 1-17页

作者： Hongzhi YAN Ruzhu WANG Chuan Zhang Zhenyuan Xu Bin Hu Zhao Shao Institution of Refrigeration and Cryogenics MOE Engineering Research Center of Solar EnergyShanghai Jiao Tong UniversityShanghai 200240China Institute of Energy Peking University5 Yiheyuan RoadBeijing 100871China

heating decarbonization is a major challenge for China to meet its 2060 carbon neutral commitment,yet most existing studies on China’s carbon neutrality focus on supply side(e.g.,grid decarbonization,zero-carbon fuel)rather than demand side(e.g.,heating and cooling in buildings and industry).In terms of end use energy consumption,heating and cooling accounts for 50% of the total energy consumption,and heat pumps would be an effective driver for heating decarbonization along with the decarbonization on power generation side.Previous study has discussed the underestimated role of the heat pump in achieving China’s goal of carbon neutrality by 2060.In this paper,various investigation and assessments on heat pumps from research to applications are presented.The maximum decarbonization potential from heat pump in a carbon neutral China future could reach around 1532Mton and 670Mton for buildings and industrial heating respectively,which show nearly 2 billion tons CO_(2) emission reduction,20% current CO_(2) emission in China.Moreover,a region-specific technology roadmap for heat pump development in China is suggested.With collaborated efforts from government incentive,technology R&D,and market regulation,heat pump could play a significant role in China’s 2060 carbon neutrality.

关键词： Carbon neutrality heat pump heating decarbonization Techno-economic assessment Technological roadmap Building heating Industrial heating

Resistance-capacitance model of the capillary heat exchanger in subway tunnels

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Energy and Built Environment

Energy and Built Environment 2024年第1期5卷 1-8页

作者： Zhen Tong Hao Wu Yiming Guan Yongming Ji Songtao Hu School of Environmental and Municipal Engineering Qingdao University of TechnologyQingdao 266033China

The subway operation generates a large amount of waste heat,which will lead to a disruption of the underground thermal balance.To remove the heat,a ground source heat pump system adopting capillary net as the front-end heat exchanger can be built in the tunnels to recycle the waste heat and use it for building heating.Different simulation method was used to analyze the heat transfer process in the tunnel and the surrounding rock.The existing simulation method usually takes a long time for calculation and can not be used for a real-time regulation of the system.Based on the concept of thermoelectric analogy,a resistance-capacitance(RC)model was proposed for rapid prediction and analysis on the heat transfer of the capillary net in subway tunnel.The annual thermal response in the tunnel was analyzed,and the influence of the tunnel air temperature and the capillary inlet water temperature was examined using this model.The maximum heat transfer flux of the capillary in summer(release heat)and in winter(extract heat)was 55.27 W/m 2 and 38.33 W/m 2,respectively.The effect of capillary inlet water temperature was more remarkable than that of the tunnel air temperature on the capillary heat exchange process.

关键词： Subway tunnel heat pump Capillary heat exchanger Resistance-capacitance model

Critical assessment of R410A alternatives for mini-split air conditioners in the Egyptian market

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Energy and Built Environment

Energy and Built Environment 2024年第3期5卷 426-445页

作者： Omar M.Zaki Omar Abdelaziz Mechanical Power Engineering Department Faculty of EngineeringCairo UniversityGiza 12613Egypt Department of Mechanical Engineering The American University in CairoAUC AvenueNew Cairo 11835Egypt

In this study,the potential implementation of three different low-GWP refrigerants(R32,R452B,and R454B)as replacements for R410A was investigated.The study was performed using a simulation tool developed by the authors called RACHP-Lab,which is a vapor compression system simulation tool developed based on physics-based simulation for typical mini-split air conditioners.The simulation study was carried out and validated using experimental performance data of 10 different air conditioning units available in the Egyptian market.The units included fixed-speed or variable-speed compressors and operated in cooling or heating modes.Drop-in replace-ment with the new refrigerants was carried out.For R32,the capacity increased between 4.9%and 13%for cooling cases,and 6.3%and 12.4%for heating cases.However,COP did not improve in all cases.For R452B and R454B with direct replacement,the capacity nearly remained the same,with an increase of COP between 1.6%and 8.0%.Soft optimization was also conducted on cooling cases where compressor suction superheat,condenser subcooling,and compressor volumetric speed were optimized to maximize COP while maintaining the original capacity of R410A.R32 showed an improvement of COP over R410A between 4.6%and 15.5%,while for R452B and R454B between 2.2%and 13.2%.

关键词： Air conditioner heat pump Alternative refrigerants Vapor compression cycle modeling

Thermodynamic Evaluation of Transcritical CO_(2) heat pump Considering Temperature Matching under the Constraint of heat Transfer Pinch Point

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Journal of Thermal Science 2021年第3期30卷 869-879页

作者： LIU Ruijian GAO Fengling LIANG Kunfeng WANG Lin WANG Moran MI Guoqiang LI Yachao Institute of Refrigeration and Air-Conditioning Henan University of Science and TechnologyLuoyang 471003China

The non-linear temperature glide in the supercritical CO_(2) cooling process makes the heat transfer pinch point of heat exchanger show multiplicity,like size,location distribution and quantity,which makes the thermodynamic performance of the CO_(2) transcritical cycle more complex and eventually affects the evaluation of the optimal operating state of the system.Based on the second law of thermodynamics and the constraints of heat transfer pinch,a thermodynamic evaluation method of CO_(2) transcritical heat pump system was proposed according to the degree of temperature matching.The influence mechanism of multi-characteristic change of heat transfer pinch point on temperature matching degree and the effect of temperature matching degree on thermodynamic performance of CO_(2) transcritical heat pump system were discussed.The relationship between temperature matching degree,COP and exergy efficiency of the system was analyzed.It is considered that the change of temperature matching index value can clearly characterize the change trends of COP and exergy efficiency.That is,the smaller the temperature matching degree is,the closer the temperature distribution of heat transfer fluids on both sides of the heat exchanger is to Lorenz cycle,and the greater the COP and exergy efficiency are.Furthermore,by monitoring the outlet temperature of the CO_(2) cooler,which has an essential relationship with the temperature matching degree during the heat exchange process,the deviation between actual and optimal working condition can be judged online,which is beneficial to real-time evaluation of the working state of the system.

关键词： heat pump CO_(2)transcritical cycle temperature matching degree exergy COP pinch point

Experimental Analysis of a Solar Energy Storage heat pump System

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Journal of Thermal Science 2021年第5期30卷 1491-1502页

作者： CHEN Haifei LI Guiqiang LING Yueyue FU Jie WANG Yunjie YANG Jie JIANG Lyulin ALI Badiei ZHANG Yang School of Petroleum Engineering Changzhou UniversityChangzhou 233016China School of Engineering University of HullHull HU67RXUK School of Aeronautics and Astronautics Purdue UniversityWest Lafayette 47907USA

This paper introduces a novel solar-assisted heat pump system with phase change energy storage and describes the methodology used to analyze the performance of the proposed system.A mathematical model was established for the key parts of the system including solar evaporator,condenser,phase change energy storage tank,and compressor.In parallel to the modelling work,an experimental set-up of the proposed solar energy storage heat pump system was developed.The experimental data showed that the designed system is capable of meeting cold day heating demands in rural areas of Yanbian city located in Jilin province of China.In day-time operation,the solar heat pump system stores excess energy in the energy storage tank for heating purposes.A desired indoor temperature was achieved;the average coefficient of performance of solar heat pump was identified as 4.5,and the system showed a stable performance throughout the day.In night-time operation,the energy stored in the storage tank was released through a liquid-solid change of phase in the employed phase-change material.In this way,the provision of continuous heat for ten hours was ensured within the building,and the desired indoor air conditions were achieved.

关键词： solar energy heat pump energy storage energy saving thermal performance