带经济器和蓄热器的空气源热泵性能实验研究

Experimental Study on Performance of Air Source Heat Pump with Economizer and Heat Accumulator

针对空气源热泵在我国北方严寒期存在热量供需矛盾、运行性能差的问题,构建了带经济器和蓄热器的超低温空气源热泵系统,深度利用制冷剂余热改善热泵低温运行特性。同时针对R22等氢氯氟烃类制冷剂使用受限的问题,以环保工质R417a替代R22进行对比实验,分析在不同环境温度和不同工作模式下的运行性能。实验结果表明,低温蓄热器可以大幅提高热泵系统在极寒天气下的制热量和能效比(Coefficient Of Performance,COP),在-30℃下R22和R417a的COP分别可达2.44和2.32,制热量可达5.75 kW和5.35 kW,除霜时间缩短了26.6%和25.2%。使用R417a时的系统制热量和COP虽略有下降,但是压缩机排气温度、压力均较低,有利于提高系统在低温环境下运行的安全性。

To address the issue of the contradition between heat supply and demand and poor operating performance of air-source heat pumps during the severe cold periods in northern China,a super-low temperature air-source heat pump system with an economizer and a heat accumulator was built to fully utilize the surplus heat of refrigerant and improve the low-temperature operation characteristics of the heat pump.In addition,in response to the restricted use of hydrochlorofluorocarbons such as R22,a comparative experiment was conducted using the environmentally friendly refrigerant R417a to analyze the designed operational performance under different environmental temperatures and working modes.The experimental results showed that the low-temperature heat accumulator device can significantly improve the heating capacity and Coefficient of Performance(COP)of the heat pump system in extremely cold weather.The COP of R22 and R417a can reach 2.44 and 2.32 respectively,and the heating capacity can reach 5.75 kW and 5.35 kW at-30℃.The defrosting time was reduced by 26.6%and 25.2%.Although there was a slight decrease in heating capacity and COP when using the R417a system,the exhaust temperature and pressure of the compressor were lower,which was beneficial for improving the safety of the system in low-temperature environments.