直流变频热泵热水器系统性能的影响因素研究

Research on Performance Factors of Direct-current Variable Frequency Heat Pump Water Heater

对R410a直流变频热泵热水器系统性能的影响因素进行了试验研究。结果发现：环境温度、进水温度不变时，在相同的水温温升区间内，压缩机以较高频率运行，膨胀阀保持相应的开度时，可以使系统的加热时间最短，耗电量最低。同时为了降低排气压力，随水温升高，压缩机频率应随之降低，电子膨胀阀应增大开度。另外，在环境温度22℃、进水温度20℃时，保持出水温度55℃以上，出水流量从1．8L／min增加到3．8L／min，系统制热量和COP随之增高，而且出水流量只有在3．0～4．0L／min时，系统才有最高的COP值，保持在4．0以上。

In this paper, performance factors of a R410a direct-current variable frequency heat pump water heater are experimentally studied. It is found that when ambient temperature and inlet water temperature are constant, compressor is worked at higher frequency and Electric Expansion Valve （EEV） is kept at a corresponding opening, the shortest heating time and the least power consumption of the system can be got at the same range of water temperature rise. At the same time, in order to reduce discharge pressure, compressor frequency should be reduced and EEV opening should be increased with water temperature increasing. In addition, at ambient temperature22℃ and inlet water temperature 20℃, outlet water temperature is kept above 55℃, When the outlet water flow is increased from 1.8L/min to 3.8L/min, the heat capacity and COP of the system are improved corresponding. And only when the outlet water flow is between 3.0 L/min and 4.0 L/min, the COP of the system can be achieved the maximum value and kept above 4.0.