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Operation Performance of Central Solar heating System with Seasonal Storage Water Tank in Harbin

湖南大学学报（自然科学版） 2009年第S1期36卷 111-114页

作者： YE Ling1,JIANG Yi-qiang1,YAO Yang1,ZHANG Shi-cong2(1.institute of heat pump and air conditioning technology,Harbin institute of technology,Harbin,Heilongjiang 150090,China 2.institute of Built Environment and Energy Efficiency,China Academy of Building Research,Beijing 100013,China) institute of heat pump and air conditioning technology Harbin Institute of Technology Harbin 150090 China institute of Built Environment and Energy Efficiency China Academy of Building Research Beijing 100013 China

This paper presented a preliminary research on the central solar heating system with seasonal storage(CSHSSS)used in cold climate in China.A mathematical model of the solar energy seasonal storage water tank used in the central solar heating system was firstly developed based on energy conservation.This was followed by the simulation of the CSHSSS used in a two-floor villa in Harbin,and analysis of the impacts on storage water temperature of tank volume,solar collector area,tank burial depth,insulation thickness around the tank,etc.The results show there is a relatively economical tank volume to optimize the system efficiency,which decreases with increasing tank volume at the constant collector area,and increases with increasing collector area at the constant tank volume.Furthermore,the insulation thickness has obvious effect on avoiding heat loss,while the tank burial depth doesn't.In addition,the relationship between the solar collector efficiency and storage water temperature is also obtained,it decreases quickly with increasing storing water temperature,and then increases slowly after starting space heating system.These may be helpful for relevant design and optimization in cold climates in China and all over the world.

关键词： central solar heating system with seasonal storage(CSHSSS) simulation system efficiency storage water tank villa

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Operating performance of novel reverse-cycle defrosting method based on thermal energy storage for air source heat pump

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Journal of Central South University 2011年第6期18卷 2163-2169页

作者：董建锴姜益强姚杨张雪丹 institute of heat pump and air conditioning of technology Harbin Institute of Technology

To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) method based on thermal energy storage to eliminate frost off the outdoor coil surface was developed. Comparative experiments using both the stand reverse cycle defrosting (SRCD) method and the NRCD method were carried out on an experimental ASHP unit with a nominal 2.5 kW heating capacity. The results indicate that during defrosting operation, using the NRCD method improves discharge and suction pressures by 0.24 MPa and 0.19 MPa, respectively, shortens defrosting duration by 60%, and reduces the defrosting energy consumption by 48.1% in the experimental environment, compared with those by the use of SRCD method. Therefore, using the NRCD method can shorten the defrosting duration, improve the indoor thermal comfort, and reduce the defrosting energy consumption in defrosting.

关键词：逆循环除霜除霜方法空气源热泵热能储存经营业绩对比实验持续时间能源消耗

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Energy and Exergy Analysis of a Cooling/Power Cogeneration Ejector Refrigeration System

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Journal of Thermal Science 2022年第2期31卷 448-462页

作者： YANG Mengke LI Xiuzhen WANG Lin YUAN Junfei WANG Zhanwei LIANG Kunfeng institute of Refrigeration and air conditioning Henan University of Science and TechnologyLuoyang 471023China

The organic Rankine cycle is introduced into the conventional ejector refrigeration(CER)system to establish the low-grade heat-driven cooling/power cogeneration ejector refrigeration(CPC-ER)system using the isobutane as the refrigerant.In comparison with the CER system where external power is consumed by the circulating pump,the power output from the CPC-ER system is more than the power consumption of its circulating pump so that a portion of net power is derived from the CPC-ER system.Based on the mathematical model of thermodynamics,energy and exergy analysis of the CPC-ER system is carried out and compared with the CER system.The results reveal that the equivalent coefficient of performance(COP)of the CPC-ER system is 41.14%to 71.30%higher than that of the CER system,and the exergy efficiency of the CPC-ER system is 1.32 to 1.49 times higher than that of the CER system.Both the power produced by the turbine and the total exergy output from the CPC-ER system approach the maximum,as the generating temperature in the generator is up to 80°C.The CPC-ER system has the higher energy utilization efficiency than the CER system,and it is suitable for the cooling and power-required places with low-grade thermal sources.

关键词： ejector refrigeration exergy power consumption equivalent COP

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Energy Planning of Beijing Towards Low-carbon,Clean and Efficient Development in 2035

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 913-928页

作者： Chengzhou Li Ningling Wang Xiaohu Shen Yumeng Zhang Zhiping Yang Xiaofeng Tong François Maréchal Ligang Wang Yongping Yang institute of Energy Power Innovation North China Electric Power UniversityBeijing 102206China School of Energy Power and Mechanical Engineering and National Research Center for Thermal Power Engineering and TechnologyNorth China Electric Power UniversityBeijing 102206China Industrial Process and Energy Systems Engineering Swiss Federal Institute of Technology in LausanneSionSwitzerland

Energy transition towards clean,efficient energy supply has been a common sense of the government and public in China.However,lacking reasonable planning will lead to undisciplined development,resource waste,and excessive investment.In this context,this paper investigates potential pathways of Beijing energy transition towards a high-level low-carbon,clean and efficient energy system in 2035 with an extended energysocpe model.Firstly,based on available data,future energy demands are predicted by a newly proposed hybrid forecasting method,which combines the traditional regression model,grey model,and support vector machine model with an entropy-based weighted factor.Secondly,the superstructure-based optimization model is employed to investigate the system configuration and operation strategy of the future Beijing energy system.Finally,the uncertainty impact of electricity price,natural gas price,hydrogen price,and the capital expenditures of electrolyzer and steam methane reforming for hydrogen applications are studied.The forecasting results show that all walks of life will witness a continuously increasing energy demand in multiple sectors of Beijing towards 2035.The planning results suggest that the imported electricity and natural gas will dominate the energy supply of Beijing in 2035 with a contribution of 86%of the energy resources consumption of 384 TWh.Moreover,the energy system presents a high end-use electrification level of 65%and high penetration of efficient technologies,which supply 119 TWh via combined heat and power,26 TWh via heat pump and 95 TWh via district heating network.The energy use of various sectors of energy resources,technologies and end-use are closely related.Hydrogen will have an increased penetration in the private mobility sector,but the locally generated hydrogen is mainly from steam methane reforming technology.

关键词： Energy transition energy planning carbonneutral demand forecasting energyscope

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循环单井与含水层的原水交换

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太阳能学报 2010年第6期31卷 743-748页

作者：倪龙姜益强姚杨马最良 institute of heat pump and air conditioning technology Harbin Institute of Technology Harbin 150090 China

建立了循环单井地下水流动和换热的数学模型,并通过现场试验的数值模拟验证了模型的正确性。采用原水交换比和原水交换负荷比定量描述了循环单井的原水交换现象。对于典型算例,循环单井的原水交换比为29.6%,原水交换负荷比为23.4%,且基... 详细信息

建立了循环单井地下水流动和换热的数学模型,并通过现场试验的数值模拟验证了模型的正确性。采用原水交换比和原水交换负荷比定量描述了循环单井的原水交换现象。对于典型算例,循环单井的原水交换比为29.6%,原水交换负荷比为23.4%,且基本不随时间变化。原水交换的存在,使得循环单井的热交换效率大大高于土壤源热泵闭式地下换热器,承担负荷的能力也显著提高。

关键词：循环单井含水层水交换负荷比土壤源热泵随时间变化热交换效率流动和换热地下换热器现场试验数学模型模拟验证定量描述正确性地下水现象数值能力典型

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Optimizing environmental insulation thickness of buildings with CHP-based district heating system based on amount of energy and energy grade

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Frontiers in Energy 2022年第4期16卷 613-628页

作者： Yumei ZHANG Pengfei JIE Chunhua LIU Jing LI School of Mechanical Engineering Beijing Institute of Petrochemical TechnologyBeijing 102617China Engineering and technology R&D Center of Clean air conditioning in Colleges of Shandong Shandong Huayu University of TechnologyDezhou 253000China China Environmental Resources technology Co. LtdBeijing 100012China

The increase of insulation thickness(IT)results in the decrease of the heat demand and heat medium temperature.A mathematical model on the optimum environmental insulation thickness(OEIT)for minimizing the annual total environmental impact was established based on the amount of energy and energy grade reduction.Besides,a case study was conducted based on a residential community with a combined heat and power(CHP)-based district heating system(DHS)in Tianjin,China.Moreover,the effect of IT on heat demand,heat medium temperature,exhaust heat,extracted heat,coal consumption,carbon dioxide(CO_(2))emissions and sulfur dioxide(SO_(2))emissions as well as the effect of three types of insulation materials(i.e.,expanded polystyrene,rock wool and glass wool)on the OEIT and minimum annual total environmental impact were studied.The results reveal that the optimization model can be used to determine the OEIT.When the OEIT of expanded polystyrene,rock wool and glass wool is used,the annual total environmental impact can be reduced by 84.563%,83.211%,and 86.104%,respectively.It can be found that glass wool is more beneficial to the environment compared with expanded polystyrene and rock wool.

关键词： optimum environmental insulation thickness heat medium temperature energy grade extracted heat exhaust heat

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Experimental Investigation of heat Transfer in Microchannel with Inlet Cavitation Structure

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Journal of Thermal Science 2021年第1期30卷 294-301页

作者： YUAN Junfei WANG Lin WANG Zhanwei TAN Yingying institute of Refrigeration and air conditioning Henan University of Science and TechnologyLuoyang 471023China

heat transfer of R134 a through the microchannel with an inlet reentrant cavitation structure was investigated for high flux thermal management of electronic devices.The cavitating flow patterns,pressure,and heat transfer characteristics were studied in the range of effective heat fluxes from 0 to 138.4 W/cm2 with mass flow velocities from 2.12 to 5.23 m/s.A stable and ideal starting point of two phase flow and heat transfer was commendably provided by the inlet cavitation orifice.There existed an axis deviation liquid jet after the micro-orifice.The refrigeration vapor was generated from the cavitation structure but liquidized at the downstream of the channel.The wall temperature along flow orientation presented an opposite trend under the test states with or without heat input.The cavitation structure can significantly suppress the flow oscillation in microchannels and the outlet pressure fluctuation reduced about 72%compared with the fluctuation at the entrance.The heat transfer coefficient had been distinctly impacted by heat flux at lower heat input and then maintained the value nearly constant of 11.0 W/(cm^(2)·K)with the critical heat flux of 88.4 W/cm2.

关键词： heat transfer cavitation structure flow pattern pressure oscillation microchannel

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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

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Evaporating Temperature Uniformity of the Pulsating heat Pipe with Surfactant Solutions at Different Concentrations

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Journal of Thermal Science 2023年第1期32卷 183-191页

作者： BAO Kangli WANG Xuehui ZHANG Peng-E HAN Xiaohong TAN Jianming State Key Laboratory of air-conditioning Equipment and System Energy Conservation GREE Electric Appliances Inc.of ZhuhaiZhuhai 519070China Key Laboratory of Refrigeration and Cryogenic technology of Zhejiang Province Institute of Refrigeration and CryogenicsZhejiang UniversityHangzhou 310027China

The evaporating section of the pulsating heat pipe(PHP)is in direct contact with the electronics when it is used for heat dissipation,and thus the evaporating temperature uniformity has an important effect on the safe and reliable operation of electronic equipment.On the basis of these conditions,an experimental study on the evaporating temperature uniformity of the PHP with surfactant solutions at different concentrations was conducted at the heat fluxes of(1911–19427)W/m^(2).Sodium stearate was utilized for the solute;the surfactant solutions were prepared with the concentrations of 0.001 wt%,0.002 wt%,and 0.004 wt%,respectively,and the filling ratios of the PHP were 0.31,0.44 and 0.57,respectively.The experimental results revealed that under all tested working conditions,the highest temperature always appeared in the intermediate zone of the evaporating section.As the heat flux increased,the temperature differences among different zones rose initially and then reduced due to the change of the flow motion and the flow pattern.The evaporating temperature uniformity of the sodium stearate solutions-PHP was better than that of the deionized water-PHP,which suggested that the evaporating temperature uniformity might be improved through decreasing the surface tension.Furthermore,combined with the effect of surface tension and viscosity,for different filling ratios,the required concentration was different when the best evaporating temperature uniformity was achieved.To be specific,when the filling ratio were 0.31 and 0.44,the best evaporating temperature uniformity was achieved at the concentration of 0.004 wt%,while at the filling ratio of 0.57,the best evaporating temperature uniformity was attained at the concentration of 0.002 wt%.

关键词： pulsating heat pipe surface tension evaporating temperature uniformity heat transfer

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Improved method and case study of ground-coupled heat pump system design

Improved method and case study of ground-coupled heat pump s...

引用

2011 2nd International Conference on Advances in Energy Engineering(ICAEE)

作者： Zhang Xuedan Jiang Yiqiang Yao Yang institute of heat pump and air conditioning technology Harbin Institute of Technology

In this paper,the yearly performance of a library building located in Harbin,China,equipped with a ground-coupled heat pump（GCHP） system,was simulated and its ground heat exchanger（GHE） was designed in the TRNSYS 17 environment.Utilizing the hourly load simulation results,a TRNSYS model was developed to analyze underground thermal balance of the entire system,obtaining the 30-year operation conditions of the reference building.According to simulation results,annual average storage temperature,the highest and lowest inlet temperature of the heat pump,factors that influence efficiency of the system,change as the number of boreholes changes.And the optimized length of heat exchangers was studied,as well as method of determining the concentration of antifreeze in heat-transfer fluid in cold regions.

关键词： GCHP GHE TRNSYS Optimized design Underground thermal balance

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