COMPARISON AND ANALYSIS ON MULTI-OBJECTIVES OF CASCADE REFRIGERATION SYSTEM USING CO_2 AS LOW TEMPERATURE CYCLE REFRIGERANT

摘要

In this paper, based on the thermodynamics, economy and environment cascade refrigeration systems of R290, R32, R717 and R404A as high-temperature cycle refrigerant respectively, CO_2 as low-temperature cycle refrigerant are compared and analyzed in multiple target. It is concluded that, under the same conditions, the cascade refrigeration system using R717 as high-temperature circuit refrigerant has higher thermal efficiency, better economy and more friendly environment compared to the other three cascade refrigeration systems. R290/CO_2 and R32/CO_2 cascade refrigeration systems have similar thermal efficiency and friendly environment, but the R290/CO_2 cascade refrigeration system has better economy. The coefficient of performance, economyand environment of the R404A/CO_2 cascade refrigeration system compared with that of the R717/CO_2, R290/CO_2 and R32/CO_2 cascade refrigeration system respectively decreace by 14.1%, 7.5%, 13.7%, 8.0%, 5.0%, 7.8% and 6.6%, 4.4%, 6.8%.