Theoretical investigation on an ejector–expansion refrigeration cycle using zeotropic mixture R290/R600a for applications in domestic refrigerator/freezers

This paper presents a modified vapor–compression refrigeration cycle (MVRC) for applications in domestic refrigerator/freezers using zeotropic mixture R290/R600a. In the MVRC cycle, an ejector and a phase separator are added based on a traditional vapor–compression refrigeration cycle (TVRC) to improve the cycle performance. The coefficient of performance COP, volumetric cooling capacity, exergy loss and exergy efficiency are theoretically investigated for the MVRC cycle and compared with the TVRC cycle. The results show that the MVRC cycle outperforms the TVRC cycle under all given operating conditions and the advantage is more obvious at lower evaporating temperature, lower subcooling temperature and higher condensing temperature. Specifically, the COP and volumetric cooling capacity can be improved maximally by 16.71% and 34.97%, respectively. The exergy efficiency can be raised maximally by 6.71% and the total exergy loss can be reduced maximally by 24.47%. The further simulation results indicate that there exists an optimal mixture composition for the MVRC cycle that could obtain the maximum COP.