Comparative studies of ejector-expansion vapor compression refrigeration cycles for applications in domestic refrigerator-freezers

EVRCs (ejector-expansion vapor-compression refrigeration cycles) applied in domestic refrigerator-freezers have been concerned duo to their potentials of improving cycle performance. However, the previously presented EVRCs with various cycle configurations are still limited to favorable performance improvement. Therefore, further development is required to promote the use of EVRCs. This paper summarizes the existing EVRCs for promising applications in domestic refrigerator-freezers. Considering the limited capacity of the existing EVRCs to enhance cycle performance, we further present a novel MEVRC (modified EVRC), in which the use of the two-phase ejector to more efficiently recover the expansion work would significantly enhance the overall system performance. A mathematical model is developed to carry out comparative simulation studies between different EVRCs. According to the results of the simulation for the EVRCs using the refrigerant R600a, the MEVRC can reach a highest pressure lift ratio of the ejector and give most excellent performance improvements in the COP (coefficient of performance) and the volumetric refrigeration capacity compared with the other EVRCs. Therefore, the potential use of MEVRC deserves further experimental validation. The present study aims to provide a deep insight into EVRCs and contribute to the development of ejector expansion refrigeration technologies in domestic refrigeration.