两种自然冷源过冷对热泵制热性能影响的对比

Comparison of the Heating Performance of Heat Pumps based on Two Types of Natural Sub-cooling

利用自然冷源过冷能够改善热泵的低温制热性能。本文提出主路过冷和辅助回路过冷两种利用自然冷源过冷的循环原理,对其进行理论分析,并搭建了实验台。针对R32为工质的蒸气压缩式热泵进行实验,研究热泵在主路过冷、辅助回路过冷及单级运行模式下,排气温度、制热量、制热COP等参数的变化规律。结果表明:在冷凝温度为40℃,蒸发温度为-20～5℃,吸气过热度为5℃的条件下,当过冷体积流量增加0.02 m^3/h时,主路过冷系统与辅助回路过冷系统的排气温度分别降低6.8℃和8.2℃;制热量分别降低6.4%和10%;制热COP分别降低2.5%和5%。

The heating performance of a heat pump can be improved by using a natural cold source.In this study,two types of sub-cooling systems with natural cold source were proposed:main loop and by-pass loop.A theoretical analysis was conducted and an integrated test bench for an R32 vapor compression heat pump was built.Running parameters such as the discharge temperature,heating capacity and heating coefficient of performance(COP)were investigated in the test bench based on three operation modes:main loop sub-cooling,by-pass loop sub-cooling,and a single-stage system.The results showed that for the main loop and by-pass loop sub-cooling systems,under the condition of condensing temperature 40℃,evaporating temperature-20~5℃and vapor suction super heat 5℃,when the sub-cooling volume flow rate increased 0.02 m^3/h,the discharge temperature was reduced to 6.8℃and 8.2℃,respectively.In addition,the heating capacity was reduced by 6.4%and 10%,and the heating COP was reduced by 2.5%and 5%,respectively.