R404A在螺杆式制冷机组中替代R22的性能研究

对比分析制冷剂R22和R404A应用于螺杆式压缩机的制冷量、功耗、EER和排气温度及其所需内容积比值的差异。结果表明,当冷凝温度为38℃,蒸发温度在-50~10℃范围内变化时,与R22相比,R404A的制冷量降低0%~17.6%,EER降低11.8%~23.1%,功耗增加7.0%~14.7%,系统压比和所需的内容积比值相差在10%以内,R404A与R22在同一螺杆式压缩机上可以相互替换使用,不需要改变螺杆式压缩机的内容积比值。机组冷冻水出口温度在-18~10.5℃范围内变化时,机组性能参数(制冷量、功率、EER)变化曲线基本与随蒸发温度变化的性能参数曲线类似。R404A在系统含水量、清洁度、密封性、使用的冷冻油等方面与R22有所不同,在生产和应用中需要加以注意。

Performance study on screw refrigeration unit using R404Aas substitute of R22

The differences between R22 and R404 A applied to screw refrigeration compressors are analyzed contrastively,including the cooling capacity,power consumption,EER,exhaust temperature and the required inner volume ratio.The results show that,under the condition of condensing temperature of 38℃,when evaporating temperature changes from-50℃to 10℃,compared with R22,the cooling capacity of R404 A is reduced by0%-17.6%,EERis reduced by 11.8%-23.1%,power consumption is increased by 7%-14.7%,and the differences of system pressure ratio and the required inner volume ratio are both within 10%.R404 A and R22 can be substituted for the same screw compressor without changing the inner volume ratio of the screw compressor.When the temperature of frozen water changes from-18℃to 10.5℃in the same screw unit,the change curves of units＇ performance parameters（cooling capacity,power,EER）are basically similar to the ones changing with the evaporating temperature.And the water content,cleanliness,sealing and refrigerant oil of R404 A system are different from those of R22,which need some attentions in the production and application.