压缩机频率对R410A/R410A复叠式热泵系统性能的试验研究

Experimental study on compressor frequency performance of R410A/R410A cascade heat pump system

通过搭建R410A/R410A复叠式热泵系统试验台对比了在改变高温级或低温级压缩机频率下热泵系统性能的的变化情况,结果表明:在同一工况下,压缩机频率由50 Hz增加到80 Hz,高温级压缩机频率改变时的最小复叠温差仍大于低温级压缩机频率改变时的最大复叠温差;在系统运行未达到最高COP时,增加低温级压缩机频率所带来COP的升高或降低在数值上明显大于增加高温级压缩机频率,且低温级压缩机频率改变时COP的峰值也明显高于改变高温级压缩机的频率;为了更好地研究低温压缩机频率对复叠热泵系统性能的影响,通过对比试验发现改变高温级或低温级压缩机频率时的COP曲线均呈现先增大后减小的趋势,COP达到峰值时,高温级压缩机的最佳频率为53 Hz,低温级压缩机的最佳频率随蒸发工况的降低而降低,压缩机的最佳频率只能使系统在该工况下达到最高COP,在最佳频率下运行的系统COP所能达到的峰值仍然由所处工况决定。

By building the R410A/R410A cascade heat pump system test bench,the change of the performance of the heat pump system was compared by changing the frequency of the high temperature or low temperature compressor.The results show that under the same working conditions,the compressor frequency was increased from 50 Hz to 80 Hz.The min.cascade temperature difference when the high-temperature compressor frequency was changed was still greater than the max.cascade temperature difference when the frequency of the low-temperature compressor was changed;and when the system operation did not reach the highest COP,the increase or decrease of COP brought by increase of the low-temperature compressor frequency was significantly greater than increase of high-temperature compressor frequency,and the peak of COP when the low-temperature compressor frequency was changed was also significantly greater than that when the high-temperature compressor frequency was changed;In order to better study the effect of low-temperature compressor frequency on the performance of cascade heat pump system,it was found through comparison that the COP curves when the high-temperature or low-temperature compressor frequency was changed all presented the trend of first increase and then decrease.When the COP reached the peak,the optimal frequency of high-temperature compressor was 53 Hz,and the optimal frequency of the low-temperature compressor decreased with the decrease of evaporation condition.The optimal frequency of the compressor could only make the system reach the highest COP under this condition,and the peak that the COP of the system operating at the optimal frequency could achieve was still determined by the operating conditions.