热泵蒸汽系统准两级压缩联合过冷器循环的性能分析及优化

Performance analysis and optimization of a coupling sub-cooler heat pump steam system in a quasi two-stage compression cycle

为了克服高压比的运行工况对能效系数(COP)、排气温度等热泵系统循环、安全性能的影响,将准两级压缩联合过冷器的循环方式引入经典的热泵蒸汽系统,在低温热源水输入温度固定为65℃、冷凝温度变化区间为115~135℃的工况下,以R245fa为工质,对经典系统及改进系统进行理论循环性能对比,并以取得更高COP为目标对改进系统的补气参数(补气率B)和过冷器参数(热源水过冷率A)进行优化。结果表明:在所考察的冷凝温度区间内,采用准两级压缩联合过冷器的循环方式下的改进系统取得了更好的循环与安全性能,当B和A的典型值分别取为0.4和0.2时,改进系统COP较经典系统平均提高了13.5%,排气温度与压缩比平均降低了1.72℃与19.2%,采用优化过的补气率和过冷率参数后,改进系统的COP可平均提高32.36%。

A sub-cooler and quasi two-stage compression cycle were introduced for classical heat pumpsteam system to overcome the negative effects on coefficient of performance(COP)and exhausttemperature of high compression ratio.Simple and revised systems were conducted in a comparativestudy on their theoretical cycle performance,at the fixed input heat source temperature of65℃andcondensing temperature range of115-135℃,using R245fa as working fluid.Then the parameters ofeconomizer(supplement rate of gas,expressed as B)and sub-cooler(sub-cooling rate of heat sourcewater,expressed as A)were optimized to achieve higher COP.The result showed that,the revisedsystem presents better cycle and safety performances,when adopting0.4and0.2as the typical valuefor B and A respectively,increasing COP value by13.5%,cutting exhaust temperature and compressionratio by1.72℃and19.2%,on average.The revised system using optimized parameters of economizerand sub-cooler can achieve a mean increase on COP of32.36%.