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
Preliminary investigation shows that air sourced type heat pumps by energy efficiency are competitive with gas boilers having 93% of coefficient of performance （COP） if heat pumps are used in climatic zones, having ...Preliminary investigation shows that air sourced type heat pumps by energy efficiency are competitive with gas boilers having 93% of coefficient of performance （COP） if heat pumps are used in climatic zones, having outside air temperature higher than （-3 ℃ to -5 ℃）. But, in such conditions the heat pump＇s evaporator is covered by ice crust, which cuts off the flow of outside air-heat source through the evaporator of heat pump. For avoiding stating problems it is recommended to use as heat source a mixture of waste warm gases. In this article a high efficiency heating-cooling system is developed, consisting of warm gases mixture sourced heat pump, heating boiler operating simultaneously with heat pump and solar air heater. The heating demand of the served house is shared between boiler and heat pump. Instead of outside air the warm gases mixture enters into evaporator of heat pump. A new construction of heat exchanger was developed. The article presents the structure and principle of operation, as well as the method for optimization and design of suggested system. Analysis proved high energy efficiency and cost effectiveness of the new system.展开更多
ASHP （air source heat pump） water heater is a renewable and energy efficient device used for sanitary hot water production. The system comprises of a storage tank and heat pump connected by pipes. These major units ...ASHP （air source heat pump） water heater is a renewable and energy efficient device used for sanitary hot water production. The system comprises of a storage tank and heat pump connected by pipes. These major units can either be compact as in the integrated model or split as in the retro-fit model. In this research, the analysis of energy losses was performed using SIRAC （the Southern African refrigeration and air conditioning） residential split type heat pump of 1.2 kW input power to retrofit a 200 liter high pressure kwikhot storage tank without hot water being drawn off for the entire monitoring period. Likewise to experimentally determine the losses DAS （data acquisition system） was designed and built to measure Ta （ambient temperature; RH-relative humidity）, RH, To （ASHP outlet water temperature）, Ti （ASHP inlet water temperature） and Vh. （volume of water heated by ASHP unit）.The results showed that the heat energy gain to compensate standby losses could range from 1.8 kWh to 2.1 kWh with the corresponding electrical energy used by ASHP water heater ranging from 0.55 kWh to 0.66 kWh. The standby losses depend primarily on the Vh, the Ta and the RH while the influence of （To - Ti） is secondary. The results can be of valuable interest to manufacturer of retrofit ASHP unit for hot water production when matching the electrical energy required to compensate for the standby losses.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 ℃.
文摘Preliminary investigation shows that air sourced type heat pumps by energy efficiency are competitive with gas boilers having 93% of coefficient of performance （COP） if heat pumps are used in climatic zones, having outside air temperature higher than （-3 ℃ to -5 ℃）. But, in such conditions the heat pump＇s evaporator is covered by ice crust, which cuts off the flow of outside air-heat source through the evaporator of heat pump. For avoiding stating problems it is recommended to use as heat source a mixture of waste warm gases. In this article a high efficiency heating-cooling system is developed, consisting of warm gases mixture sourced heat pump, heating boiler operating simultaneously with heat pump and solar air heater. The heating demand of the served house is shared between boiler and heat pump. Instead of outside air the warm gases mixture enters into evaporator of heat pump. A new construction of heat exchanger was developed. The article presents the structure and principle of operation, as well as the method for optimization and design of suggested system. Analysis proved high energy efficiency and cost effectiveness of the new system.
文摘ASHP （air source heat pump） water heater is a renewable and energy efficient device used for sanitary hot water production. The system comprises of a storage tank and heat pump connected by pipes. These major units can either be compact as in the integrated model or split as in the retro-fit model. In this research, the analysis of energy losses was performed using SIRAC （the Southern African refrigeration and air conditioning） residential split type heat pump of 1.2 kW input power to retrofit a 200 liter high pressure kwikhot storage tank without hot water being drawn off for the entire monitoring period. Likewise to experimentally determine the losses DAS （data acquisition system） was designed and built to measure Ta （ambient temperature; RH-relative humidity）, RH, To （ASHP outlet water temperature）, Ti （ASHP inlet water temperature） and Vh. （volume of water heated by ASHP unit）.The results showed that the heat energy gain to compensate standby losses could range from 1.8 kWh to 2.1 kWh with the corresponding electrical energy used by ASHP water heater ranging from 0.55 kWh to 0.66 kWh. The standby losses depend primarily on the Vh, the Ta and the RH while the influence of （To - Ti） is secondary. The results can be of valuable interest to manufacturer of retrofit ASHP unit for hot water production when matching the electrical energy required to compensate for the standby losses.
