Theoretical study of an internal auto-cascade refrigeration cycle using mixture R290/R600

This paper proposes a novel internal auto-cascade refrigeration cycle (IARC) operating with the zeotropic mixture of R290/R600 for domestic refrigerator-freezers. In the IARC system, a cascade heat exchanger associated with a phase separator is introduced to achieve auto refrigerant cascade refrigeration and enhance the overall system performance. The performances of the IARC are evaluated by using the developed mathematical model, and then compared with that of the conventional refrigeration cycle (CRC). According to the simulation results, the IARC with R290/R600 has 9.5-21.1% improvement in coefficient of performance (COP), 14.9-34.1% improvement in volumetric refrigeration capacity compared with those of the CRC under the same given operating conditions. The performance characteristics of the IARC may show its promise in domestic refrigerator-freezers applications.