Performance of condensing and evaporating characteristics of an auto-refrigerating cascade system

Abstract

The condensing and evaporating characteristics of an auto-refrigerating cascade cycle employing ternary zeotropic mixture R600a/R23/R14 are studied in this article. When the outlet temperature of condenser is 300 K, the composition ratio of R600a/R23/R14 in liquid mixture is 78.04/12.62/9.34, respectively. In the liquid mixture, the R600a is the dominating component. The separation mass fraction of R23 by phase separators I and II is 12.62% and 30.27%, respectively; 78.04% refrigerant R600a can be separated by phase separator I, and 9.34% refrigerant R14 is liquid. In evaporator, the composition ratio of R600a occupies 6.31%, while the low-boiling-point refrigerant R14 accounts for 45.64%. The changing of composition ratio could significantly influence the cooling loads while had a little influence on the changing of the evaporating temperature. The maximum cooling load is 85 and 50 W for composition 35/35/30 and composition 35/30/35, respectively, and the maximum coefficients of performance are 14.4% and 8.5%, respectively.