Performance evaluation on an internal auto-cascade refrigeration cycle with mixture refrigerant R290/R600a

This paper proposes an internal auto-cascade refrigeration cycle (IARC) operating with the zeotropic mixture of R290/R600a or 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. Performances of the IARC are evaluated by using a developed mathematical model, and then compared with that of the conventional refrigeration cycle (CRC). According to the simulation results, the IARC with R290/R600a has 7.8-13.3% improvement in coefficient of performance (COP), 10.2-17.1% improvement in volumetric refrigeration capacity and 7.4-12.3% reduction in pressure ratio of compressor compared with those of the CRC under the same given operating conditions. The further simulation results of the IARC using refrigerant R290/R600 also indicate that the performances of COP, volumetric refrigeration capacity and pressure ratio of compressor could be further improved. The performance characteristics of the IARC may show its promise in domestic refrigerator-freezers applications.