回热对跨临界CO2热泵系统性能影响的实验研究

本文实验研究了回热器的回热率对跨临界CO2热泵系统性能的影响。结果表明:在一定压缩机频率下,随着排气压力的升高,系统制热量和COPh都存在最大值,并分别存在对应最大制热量和最大COPh的最优排气压力;在25Hz压缩机频率下,系统在低排气压力下运行时,引入回热器才能提高系统COPh,且引入回热器可在较低排气压力下,获得更高的系统COPh;在一定压缩机频率下,系统分别存在最大制热量、最高出水温度和最大COPh对应的最优回热率.在本实验条件下,如果以系统获得最大COPh为设计目标,系统回热率取15%左右为宜;如果以系统获得最高出水温度为设计目标,系统回热率取5%左右为宜。

Experimental Study on the Compacts of Regenerative Heat on the Performance of the Transcritical CO2 Heat Pump System

The compacts of regenerative heating rate of recuperator on the performance of a transcritical CO2 heat pump system were experimentally investigated in this work.The results indicate that at a fixed compressor frequency,the heating capacity and the COPh of the system both existed peak values with the increase of discharge pressure,and there existed the optimal discharge pressures corresponding to the maximum heating capacity and the maximum COPh,respectively.At the compressor frequency of 25 Hz,the system COPh can be improved when operated at low discharge pressure by using recuperator.And the use of recuperator can make the system obtain higher COPh at lower discharge pressure.Moreover,at the same compressor frequency,there existed the optimal regenerative heating rates corresponding to the maximum heating capacity,the highest water outlet temperature and the maximum COPh,respectively.Under the experimental conditions,if the design target is to make the system obtain the maximum COPh,the system regenerative heating rate should achieve about 15%;if the design target is to make the system provide the highest water outlet temperature,the system regenerative heating rate should attain about 5%.The research results can provide a reference for the design and application of recuperator in CO2 heat pump system.