Theoretical analysis of a double ejector-expansion autocascade refrigeration cycle using hydrocarbon mixture R290/R170

This paper proposed a double ejector-expansion autocascade refrigeration cycle (DEARC) using hydrocarbon mixture R290/R170 for applications in low-temperature freezers. In DEARC, the two ejectors are introduced to reduce the thermodynamic loss in throttling process. The performances of the traditional autocascade refrigeration cycle (ARC), single ejector-expansion autocascade refrigeration cycle (EARC) and DEARC are compared, and several important parameters for DEARC are also discussed in detail. The results indicate that DEARC is feasible and there are obvious performances improvements on theCOP, volumetric refrigeration capacity and exergic efficiency. Especially, in DEARC, the COP increases by 97.9% and 29.6% at most compared to that of ARC and EARC, respectively, the volumetric refrigeration capacity is 334.8% and 188.6% higher than that of the two cycles. In general, the DEARC provides obvious performance improvement and produces better actual operation benefit. The potential practical advantages may be worth further attention in future studies.