CO_(2)/HCs混合工质亚临界与跨临界循环的性能分析

Performance analysis of subcritical and transcritical cycles of CO_(2)/HCs mixture refrigerant

为了研究CO_(2)/HCs混合工质应用于热泵系统的性能,建立单级带节流阀亚临界循环和跨临界循环数学模型,分析了CO_(2)/R170,CO_(2)/R1270,CO_(2)/R290,CO_(2)/RC2704种混合工质的特性、不同混合工质配比对循环制冷系数COP和高压压力的影响,以及蒸发温度和冷凝温度对循环性能的影响。结果表明:在亚临界循环中,性能最好的是CO_(2)/RC270,COP c峰值为2.92,COP h峰值为3.92,质量比在0.1/0.9左右,COP c和COP h分别比其他2种工质高出了9%、26%和7.1%、18%。在跨临界循环中,CO_(2)/R1270当质量比为0.96/0.04时,COP c最大值为3.2,COP h最大值为4.2;CO_(2)/R290能有效降低高压压力,当循环的高压压力在7.5 MPa下时,CO_(2)/R290的质量比为0.9/0.1时COP最大,达到2.9,与纯CO_(2)在相同高压压力下相比,COP提高了93%。

In order to study the performance of CO_(2)/HCs mixture refrigerant applied to heat pump systems,mathematical models of subcritical and transcritical cycles of single-stage throttle valves were established.The characteristics of CO_(2)/R170,CO_(2)/R1270,CO_(2)/R290,CO_(2)/RC270 were analyzed,the effects of different ratios of mixture refrigerant on the coefficient of performance(COP)and high pressure were analyzed,and the effects of evaporation temperature and condensation temperature on system performance were analyzed.The results show that in the subcritical cycle,CO_(2)/RC270 has the best performance,with COP c peak value of 2.92 and COP h peak value of 3.92.When the mass fraction ratio is about 0.1/0.9,COP c and COP h are 9%,26%and 7.1%,18%,respectively,higher than the other two working fluids.In the transcritical cycle,when the ratio of CO_(2)/R1270 is 0.96/0.04,the maximum value of COP c is 3.2 and the maximum value of COP h is 4.2;CO_(2)/R290 can effectively reduce the high pressure,when the high pressure of the system is below 7.5 MPa,the maximum value of COP reaches 2.9 when the ratio of CO_(2)/R290 is 0.9/0.1,which is 93%higher than pure CO_(2) at the same high pressure.