蓄热型热泵热水器单级与复叠循环性能比较  

Performance comparison of single stage and cascade heat pump water heater with PCM

作　　者：巫江虹[1] 游少芳[1] 谢方[1] 朱钰娟[1] 肖皓斌 

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510641 [2]广东西屋康达空调有限公司,广东佛山528300

出　　处：《化工学报》2011年第7期1879-1884,共6页CIESC Journal

基　　金：广东省科技厅产学研项目(2009B090300380)~~

摘　　要：引言热泵机组的复叠循环,可以降低在寒冷气候下压缩机的压缩比,提高其制热效率[1]。Agyeni m等[2]采用石蜡为相变蓄热材料（PCM）,分析了空气源热泵热水器内部传热特性,由于石蜡的热导率较小导致蓄热放热效率较低,The energy stored and released process of cascade air source heat pump water heater with phase change material（PCM） was investigated experimentally.R404a was selected as refrigerant of low-temperature stage and R134a as refrigerant of high-temperature stage.At different ambient temperatures,heat transfer processes and variation of parameters for the single and cascade heat pump systems were compared,and the optimum ambient temperature,at which the cascade system should be switched to single stage system,was analyzed in order to guarantee the best system performance.The results showed that in the cascade system the heat transfer presented time-lag behavior and the difference of heat transfer from the condenser to PCM and to water was in the range of 7%—10%.When the opening of electronic expansion valve at high-temperature stage was increased by 10%,the heat transfer difference decreased from 18% to 6%,benefiting the heat balance of the condensation-evaporator and improving system efficiency.The cascade system took less time for energy storage than the single system.With the two cycles,the compression ratio and exhausting temperature increased as ambient temperature decreased.COP decreased as the water outlet temperature increased and increased with the ambient temperature.For this cascade system,the optimum ambient temperature for switching between the single and cascade systems was 7℃.

关 键 词：热泵热水器 复叠式循环 单级循环 COP 

分 类 号：TB657.5[一般工业技术—制冷工程]