以空气源热泵热水机组为实验研究对象，通过改变电子膨胀阀开度，研究压缩机吸气状态对系统性能的影响，研究结果表明：(1) 在加热前期（水箱平均温度20~30 ℃），膨胀阀开度越大，系统COP（能效比）越大；在加热后期（水箱平均温度40~55 ℃），膨胀阀开度越大，系统COP越小；(2) 压缩机吸气带液可以有效改善冷凝器的换热性能，提高总换热系数，但在加热后期，压缩机大量吸气带液时，制冷剂质量流量降低造成的影响更大，因此系统制热量先上升后下降；(3) 以压缩机吸气过热度为控制对象调节电子膨胀阀，使压缩机处于少量吸气带液状态，可以有效提高系统COP。

The performance of an airsource heat pump water heaterwith different opening of electronic expansion valve is analyzed in this paper.The results show that the COP of the system is in direct proportion to the opening with the average temperature of cistern at 20~30 ℃,while it becomes in inverse proportion to the opening with the average temperature of cistern at 40~55 ℃.Although the compression with liquid refrigerant could effectively improve the performance of heat exchange in the condenser,the superabundant liquid refrigerant will lead to the decrease of the mass flow,which results in reduced heating capacity after an initial ascent.Controlling the electronic expansion valve by the superheated temperature in the suction of compressor can create a refrigerant status with a small amount of liquid in compressor,resulting in an increase in the COP of system.

TK124

上海市动力工程多相流动与传热重点实验室(13DZ2260900)