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
From the viewpoints of environmental conservation and energy efficiency,seawater-source heat pump system(SWHP) to provide district cooling and heating is applied in coastal areas.Based on the system,a heat transfer mo...From the viewpoints of environmental conservation and energy efficiency,seawater-source heat pump system(SWHP) to provide district cooling and heating is applied in coastal areas.Based on the system,a heat transfer model was established for cast heat exchanger(CHE) adopted by SWHP systems.The CHE consists of pipes immersed in the seawater and used for transferring heat between the seawater and the heat exchanger pipes of SWHP system.An experimental study was carried out to test the validity of the model.A program was developed in VB language and the effects of inlet temperature,flow rate of the secondary refrigerant and length of CHE on the results were investigated.The results of the numerical simulation are in consistence with the experiments in both winter and summer conditions.As a result,application of SWHP systems with CHE in coastal areas in China is feasible due to the favorable geographical conditions and environment.展开更多
The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is...The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.展开更多
To confirm the rheological characteristic of sewage in the research and application of urban sewage source heat pump system, the viscosity of sewage was investigated. The tube-type rheometer was used in this experimen...To confirm the rheological characteristic of sewage in the research and application of urban sewage source heat pump system, the viscosity of sewage was investigated. The tube-type rheometer was used in this experimental study, and the sewage was treated as homogeneous non-Newtonian fluid. In addition, the relational expression between viscosity parameters was developed, and the function of apparent viscosity was obtained. It is concluded that the viscosity characteristic of sewage is influenced largely by complex mixture in sewage, and the sewage has the characteristic of sheared densification fluid.展开更多
A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results, in which the solar collector was combined serially with a ground-coupled heat pump (GCHP). The uni...A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results, in which the solar collector was combined serially with a ground-coupled heat pump (GCHP). The universal optimal equations were solved by the constrained variable metric method considering both the per-formance and economics. Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating. The results indicated a system coefficient of performance (COP) of 3.9 for the optimal method under the serial heating mode, and 3.2 for the conventional one. In addition, the optimum solution also showed advantages in energy and cost saving, leading to a 16.7% improvement in the heat pump performance at 17.2% less energy consumption and 11.8% lower annual cost, respectively.展开更多
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Project(2006BAJ04A15-03) supported by the National Science and Technology Pillar Program during the Eleventh Five-year Plan Period
文摘From the viewpoints of environmental conservation and energy efficiency,seawater-source heat pump system(SWHP) to provide district cooling and heating is applied in coastal areas.Based on the system,a heat transfer model was established for cast heat exchanger(CHE) adopted by SWHP systems.The CHE consists of pipes immersed in the seawater and used for transferring heat between the seawater and the heat exchanger pipes of SWHP system.An experimental study was carried out to test the validity of the model.A program was developed in VB language and the effects of inlet temperature,flow rate of the secondary refrigerant and length of CHE on the results were investigated.The results of the numerical simulation are in consistence with the experiments in both winter and summer conditions.As a result,application of SWHP systems with CHE in coastal areas in China is feasible due to the favorable geographical conditions and environment.
基金Project(2012BAJ06B04)supported by"12th Five-Year Plan"National science and Technology,ChinaProject(2014-228)supported by Department of Housing and Urban Rural Development of Hebei,China
文摘The energy efficiency monitoring is an essential precondition for ground source heat pump system's controlling and energy saving operation. Based on the data monitoring applied in the school building, this work is focused on the parameters acquisition and operation analysis of the GSHP system in Tangshan. Results show the average COPs(coefficient of performance) are2.85 and 2.70 in summer and winter, respectively, and heat(cold) unbalance underground existed after whole year operation. The analysis of data also indicates that the direct borehole air-conditioning saved some power consumption obviously in the early stage of summer and energy saving of the GSHP system depended remarkably on its operation and management level. Besides the observation points of ground temperature are laid for a large-scale GSHP system, and the hydraulic balance of the pipes group needs to be concerned specially in safeguarding better reliability.
基金Sponsored by the National Natural Science Foundation of China (Grant No.50578048)
文摘To confirm the rheological characteristic of sewage in the research and application of urban sewage source heat pump system, the viscosity of sewage was investigated. The tube-type rheometer was used in this experimental study, and the sewage was treated as homogeneous non-Newtonian fluid. In addition, the relational expression between viscosity parameters was developed, and the function of apparent viscosity was obtained. It is concluded that the viscosity characteristic of sewage is influenced largely by complex mixture in sewage, and the sewage has the characteristic of sheared densification fluid.
基金Supported by National Major Project of Scientific and Technical Programs of China During the 11th Five-Year Plan Period (No. 2006BAJ03A06)Tianjin Municipal Project for Science and Technology Development Plan (No. 06YFSYSF03600).
文摘A mathematical optimization model was set up for a ground-solar combined system based on in-situ experimental results, in which the solar collector was combined serially with a ground-coupled heat pump (GCHP). The universal optimal equations were solved by the constrained variable metric method considering both the per-formance and economics. Then the model was applied to a specific case concerning an actual solar assisted GCHP system for space heating. The results indicated a system coefficient of performance (COP) of 3.9 for the optimal method under the serial heating mode, and 3.2 for the conventional one. In addition, the optimum solution also showed advantages in energy and cost saving, leading to a 16.7% improvement in the heat pump performance at 17.2% less energy consumption and 11.8% lower annual cost, respectively.
