R134a空气源热泵热水器实验研究与性能分析

Experimental Investigation and Performance Analysis on R134a Air Source Heat Pump Water Heater

对一台工质为R134a的空气源热泵热水器样机进行了实验测试,研究了在环境温度为20/15℃工况下,最佳充灌量(1500 g)的70%,85%,100%和115%下的系统特性,并在最佳充灌量下研究了膨胀阀开度分别为30%,45%,60%时的系统性能。结果表明系统性能随充灌量增加呈先增大后减小趋势。膨胀阀开度对系统逐时COP影响较大,在水箱温度超过32℃时,增大膨胀阀的开度可以提高系统的COP。此外,基于实验研究,论文对系统损失进行了分析。结论表明系统主要的损失分布在压缩机和冷凝器。系统效率随着水箱温度的升高而不断减小,在开度为30%和60%下,系统效率分别下降约8%和10%左右。

Experiments of an air source heat pump water heater（ASHPWH） prototype using R134a were carried out and the effects of im- proper refrigerant charge and incorrect TXV opening on the system were analyzed. The performance of the system were measured in combi- nations of four refrigerant charges, i.e. 70% ,85% , 100% and 115% of the optimal value, and three TXV opening,i, e, 30% , 45% and 60% of full opening at ambient temperature of 20/15 ℃. The results showed that the system COP was increased to a point and then ten- ded to decrease with the increase of refrigerant charge ; the expansion valve opening had a significant impact on performance, and increas- ing the TXV opening can enhance COP when water temperature is above 32 ℃. Based on the experimental investigations, an exergy analy- sis was conducted to evaluate the thermodynamic performance of the system and components in this study. It was found that excrgy losing of the system mainly occurred in the compressor and condenser. The system exergy efficiency was decreased with the increase of water temperature, and it was decreased by 8% and 10% respectively when the expansion valve opening was 30% and 60%.