复叠式制冷系统低温环路制冷剂R744(CO2)／R290的实验研究

Experimental study on R744/R290 in low-temperature circuit of cascade refrigeration system

针对工质R13的替代研究,提出了一种非共沸混合工质55%R744(CO2)/45%R290作为复叠式制冷系统低温环路的制冷剂,并在复叠式制冷实验台上进行了不同蒸发器进口温度的实验及分析.通过将该工质在各工况下的实验结论与相应工况下R13的实验结论进行对比分析,发现该物质的制冷量和制冷系数均高于R13;吸气温度、排气温度和压缩比均低于R13;当蒸发温度在-64^-67℃变化时,该物质的循环性能优于R13;在相同的初温下,当低温恒温室内空气温度降低到-55℃时,其制冷速率比R13快7.4%.

It is proposed a novel zeotrope R290（50% R744 and 45% COz） to be the refrigerant of a cascade refrigeration system in low temprature circuit. Also experiments and analysis on the different inlet tempratures of evaporator on cascade refrigeration test-bed are investigated. With comparisons of experiment results in same working condition between R290 and R13, the results show that the refrigerating capacity and coefficient of performance of R290 are higher than that of R13; the suction temperature, discharge temperature and compression ratio of R290 are lower than that of R13 ; the cycle performance of R290 is better than that of R13 when the evaporation temperature varied in -64-67 ℃ ; the refrigeration rate of R290 is higher than that of R13 by 7.4% when low indoor temperature is reduced to -55 ℃ in same initial temperature.