跨临界CO_(2)空气源热泵系统运行性能研究

System performance of air-source transcritical CO_(2) heat pump

搭建一套跨临界CO_(2)空气源热泵系统,研究在不同压缩机运行频率以及排气压力下循环系统的热力性能,通过实验对比分析频率和排气压力对吸气压力、等熵效率、压缩机功耗、排气温度、CO_(2)质量流量、系统制热量以及制热性能系数COP的影响。结果表明:排气压力不变时,只有吸气压力随着频率的上升而下降,排气温度、CO_(2)质量流量、系统制热量和压缩机功耗都随之增加。系统COP随着排气压力的增加先上升再下降,随着压缩机频率升高,系统COP减小,最优排气压力升高,在最优排气压力下,系统的COP达到峰值。当压缩机运行频率为80 Hz,排气压力为8.4 MPa时,此时最优等熵效率约为0.9,系统COP达到峰值为3.64。

An air-source transcritical CO_(2)heat pump system was built to study the thermal performance of the circulating system at different compressor operating frequencies and discharge pressures.Compared with the experimental results,the effects and variation laws of frequency and discharge pressure on suction pressure,isentropic efficiency,compressor power consumption,discharge temperature,CO_(2)mass flow,system heating capacity and coefficient of heating performance COP were analyzed.When the discharge pressure remains stable,with the increase of frequency,the suction pressure decreases and the discharge temperature,CO_(2)mass flow,system heating capacity and compressor power consumption increase,respectively.The system COP rises to the peak value and decreases with the increase of discharge pressure.With the increase of compressor frequency,the system COP decreases and the optimal discharge pressure increases.COP of the system reaches the peak value at the optimal discharge pressure.When the compressor operates at 80 Hz and the discharge pressure is 8.4 MPa,the optimal isentropic efficiency is about 0.9,and the heating COP reaches the peak value of 3.64.