To further improve the utilization efficiency of solar energy and the performance of solar heat pump heating systems,a new heating mode of a solar air-source heat pump（SASHP）is proposed,and the characteristics and p...To further improve the utilization efficiency of solar energy and the performance of solar heat pump heating systems,a new heating mode of a solar air-source heat pump（SASHP）is proposed,and the characteristics and performance of the heat pump part of this new heating system are studied.Based on a SASHP with 10 kW,the mathematical model of this system is built,and the characteristics and performance are concluded from the simulation analysis at different environmental temperatures and output water temperatures.The results show that the performance of heat pumps can be greatly improved based on the new SASHP.When the environmental temperature is 7 ℃,the coefficient of performance（COP）of the air-source heat pump（ASHP）can be increased by 26% at most.This paper sets up a base for further study on the heating system with this new SASHP in the heating season.展开更多
A new ground source heat pump system combined with radiant heating/cooling is proposed, and the principles and the advantages of the system are analyzed. A demonstration of the system is applied to a rebuilt building...A new ground source heat pump system combined with radiant heating/cooling is proposed, and the principles and the advantages of the system are analyzed. A demonstration of the system is applied to a rebuilt building： Xijindu exhibition hall, which is located in Zhenjiang city in China. Numerical studies on the thermal comfort and energy consumption of the system are carded out by using TRNSYS software. The results indicate that the system with the radiant floor method or the radiant ceiling method shows good thermal comfort without mechanical ventilation in winter. However, the system with either of the methods should add mechanical ventilation to ensure good comfort in summer. At the same level of thermal comfort, it can also be found that the annual energy consumption of the radiant ceiling system is less than that of the radiant floor system.展开更多
A district heating and hot water supply system is presented which synthetically utilizes geothermal energy,solar thermal energy and natural gas thermal energy.The multi-energy utilization system has been set at the ne...A district heating and hot water supply system is presented which synthetically utilizes geothermal energy,solar thermal energy and natural gas thermal energy.The multi-energy utilization system has been set at the new campus of Tianjin Polytechnic University(TPU),A couple of deep geothermal wells which are 2 300 m in depth were dug,Deep geothermal energy cascade utilization is achieved by two stages of plate heat exchangers(PHE) and two stages of water source heat pumps(WSHP).Shallow geothermal energy is used in assistant heating by two ground coupled heat pumps(GCHPs) with 580 vertical ground wells which are 120 m in depth.Solar thermal energy collected by vacuum tube arrays(VTAs) and geothermal energy are complementarily utilized to make domestic hot water.Superfluous solar energy can be stored in shallow soil for the GCHP utilization.The system can use fossil fuel thermal energy by two natural gas boilers(NGB) to assist in heating and making hot water.The heating energy efficiency was measured in the winter of 2010-2011.The coefficients of performance(COP) under different heating conditions are discussed.The performance of hot water production is tested in a local typical winter day and the solar thermal energy utilization factor is presented.The rusults show that the average system COP is 5.75 or 4.96 under different working conditions,and the typical solar energy utilization factor is 0.324.展开更多
An air source heat pump system (ASHPS) used in an office building is set up and studied experimentally. Its operating performance in winter is evaluated based on test data and a comparative discussion is given on the ...An air source heat pump system (ASHPS) used in an office building is set up and studied experimentally. Its operating performance in winter is evaluated based on test data and a comparative discussion is given on the effect of climate conditions and heating load ratio on the operation behavior. Then heating capacity variation caused by evaporator frosting is analyzed as well. Finally, the defrosting parameters and the technical feasibility are studied for a constant heating demand. The experimental results indicate that both the outlet water temperature drop and the system COP should be taken into account when setting defrosting parameters, and ASHPS is a viable technology for space heating and hot-water production in winter in Tianjin, which can maintain the room temperature above 19 ℃ when the outdoor temperature is -2 ℃.展开更多
The distributed energy system has achieved significant attention in respect of its application for singlebuilding cooling and heating.Researching on the life cycle environmental impact of distributed energy systems(DE...The distributed energy system has achieved significant attention in respect of its application for singlebuilding cooling and heating.Researching on the life cycle environmental impact of distributed energy systems(DES)is of great significance to encourage and guide the development of DES in China.However,the environmental performance of distributed energy systems in a building cooling and heating has not yet been carefully analyzed.In this study,based on the standards of ISO14040-2006 and ISO14044-2006,a life-cycle assessment(LCA)of a DES was conducted to quantify its environmental impact and a conventional energy system(CES)was used as the benchmark.GaBi 8 software was used for the LCA.And the Centre of Environmental Science(CML)method and Eco-indicator 99(EI 99)method were used for environmental impact assessment of midpoint and endpoint levels respectively.The results indicated that the DES showed a better life-cycle performance in the usage phase compared to the CES.The life-cycle performance of the DES was better than that of the CES both at the midpoint and endpoint levels in view of the whole lifespan.It is because the CES to DES indicator ratios for acidification potential,eutrophication potential,and global warming potential are 1.5,1.5,and 1.6,respectively at the midpoint level.And about the two types of impact indicators of ecosystem quality and human health at the endpoint level,the CES and DES ratios of the other indicators are greater than1 excepting the carcinogenicity and ozone depletion indicators.The human health threat for the DES was mainly caused by energy consumption during the usage phase.A sensitivity analysis showed that the climate change and inhalable inorganic matter varied by 1.3%and 6.1%as the electricity increased by 10%.When the natural gas increased by 10%,the climate change and inhalable inorganic matter increased by 6.3%and 3.4%,respectively.The human health threat and environmental damage caused by the DES could be significantly reduced by the optimization of natural gas and electricity consumption.展开更多
基金The National Natural Science Foundation of China(No.50676018)the National Key Technology R&D Program of China during the 11th Five-Year Plan Period(No.2008BAJ12B02)
文摘To further improve the utilization efficiency of solar energy and the performance of solar heat pump heating systems,a new heating mode of a solar air-source heat pump（SASHP）is proposed,and the characteristics and performance of the heat pump part of this new heating system are studied.Based on a SASHP with 10 kW,the mathematical model of this system is built,and the characteristics and performance are concluded from the simulation analysis at different environmental temperatures and output water temperatures.The results show that the performance of heat pumps can be greatly improved based on the new SASHP.When the environmental temperature is 7 ℃,the coefficient of performance（COP）of the air-source heat pump（ASHP）can be increased by 26% at most.This paper sets up a base for further study on the heating system with this new SASHP in the heating season.
基金The National Natural Science Foundation of China(No. 51036001 )the Natural Science Foundation of Jiangsu Province(No. BK2010043)
文摘A new ground source heat pump system combined with radiant heating/cooling is proposed, and the principles and the advantages of the system are analyzed. A demonstration of the system is applied to a rebuilt building： Xijindu exhibition hall, which is located in Zhenjiang city in China. Numerical studies on the thermal comfort and energy consumption of the system are carded out by using TRNSYS software. The results indicate that the system with the radiant floor method or the radiant ceiling method shows good thermal comfort without mechanical ventilation in winter. However, the system with either of the methods should add mechanical ventilation to ensure good comfort in summer. At the same level of thermal comfort, it can also be found that the annual energy consumption of the radiant ceiling system is less than that of the radiant floor system.
基金Project(2010DFA72740-06) supported by International Science & Technology Cooperation Program of China
文摘A district heating and hot water supply system is presented which synthetically utilizes geothermal energy,solar thermal energy and natural gas thermal energy.The multi-energy utilization system has been set at the new campus of Tianjin Polytechnic University(TPU),A couple of deep geothermal wells which are 2 300 m in depth were dug,Deep geothermal energy cascade utilization is achieved by two stages of plate heat exchangers(PHE) and two stages of water source heat pumps(WSHP).Shallow geothermal energy is used in assistant heating by two ground coupled heat pumps(GCHPs) with 580 vertical ground wells which are 120 m in depth.Solar thermal energy collected by vacuum tube arrays(VTAs) and geothermal energy are complementarily utilized to make domestic hot water.Superfluous solar energy can be stored in shallow soil for the GCHP utilization.The system can use fossil fuel thermal energy by two natural gas boilers(NGB) to assist in heating and making hot water.The heating energy efficiency was measured in the winter of 2010-2011.The coefficients of performance(COP) under different heating conditions are discussed.The performance of hot water production is tested in a local typical winter day and the solar thermal energy utilization factor is presented.The rusults show that the average system COP is 5.75 or 4.96 under different working conditions,and the typical solar energy utilization factor is 0.324.
基金Supported bythe"11th Five-Year Plan"for National Plans of Major Technology Projects
文摘An air source heat pump system (ASHPS) used in an office building is set up and studied experimentally. Its operating performance in winter is evaluated based on test data and a comparative discussion is given on the effect of climate conditions and heating load ratio on the operation behavior. Then heating capacity variation caused by evaporator frosting is analyzed as well. Finally, the defrosting parameters and the technical feasibility are studied for a constant heating demand. The experimental results indicate that both the outlet water temperature drop and the system COP should be taken into account when setting defrosting parameters, and ASHPS is a viable technology for space heating and hot-water production in winter in Tianjin, which can maintain the room temperature above 19 ℃ when the outdoor temperature is -2 ℃.
基金Projects(51676209,22008265)supported by the National Natural Science Foundation of ChinaProjects(2020JJ6072,2021JJ50007)supported by the Hunan Province Natural Science Foundation,China。
文摘The distributed energy system has achieved significant attention in respect of its application for singlebuilding cooling and heating.Researching on the life cycle environmental impact of distributed energy systems(DES)is of great significance to encourage and guide the development of DES in China.However,the environmental performance of distributed energy systems in a building cooling and heating has not yet been carefully analyzed.In this study,based on the standards of ISO14040-2006 and ISO14044-2006,a life-cycle assessment(LCA)of a DES was conducted to quantify its environmental impact and a conventional energy system(CES)was used as the benchmark.GaBi 8 software was used for the LCA.And the Centre of Environmental Science(CML)method and Eco-indicator 99(EI 99)method were used for environmental impact assessment of midpoint and endpoint levels respectively.The results indicated that the DES showed a better life-cycle performance in the usage phase compared to the CES.The life-cycle performance of the DES was better than that of the CES both at the midpoint and endpoint levels in view of the whole lifespan.It is because the CES to DES indicator ratios for acidification potential,eutrophication potential,and global warming potential are 1.5,1.5,and 1.6,respectively at the midpoint level.And about the two types of impact indicators of ecosystem quality and human health at the endpoint level,the CES and DES ratios of the other indicators are greater than1 excepting the carcinogenicity and ozone depletion indicators.The human health threat for the DES was mainly caused by energy consumption during the usage phase.A sensitivity analysis showed that the climate change and inhalable inorganic matter varied by 1.3%and 6.1%as the electricity increased by 10%.When the natural gas increased by 10%,the climate change and inhalable inorganic matter increased by 6.3%and 3.4%,respectively.The human health threat and environmental damage caused by the DES could be significantly reduced by the optimization of natural gas and electricity consumption.
