Thermodynamic analysis of the performance of a vapour compression refrigeration system, working withR290 and R600a mixtures

Environmentally benign natural refrigerants have recently attracted considerable attention due to refrigerant contributions to ozone depletion and global warming. In the group of natural refrigerants, hydrocarbons are most closely related to the HFCs. In addition to their zero ODP and very low GWP, they are compatible with common materials found in refrigerating systems. Therefore, in this study, a performance simulation of R290 and R600a mixtures (80/20, 70/30, 60/40 and 50/50 proportion by mass, designated by RM1, RM2, RM3 and RM4, respectively) in a vapour compression refrigeration system is conducted by the thermodynamic calculation of performance parameters using REFPROP software. The results show that the mixtures exhibit higher refrigerating eects than R134a. The average pressure ratio obtained for RM1, RM2, RM3 and RM4 was 19.5, 16.5, 14.0 and 11.8% lower than that of R134a, respectively. All the mixtures, except RM1, exhibited a low discharge pressure, which is more desirable in refrigeration systems. The COPs of the mixtures were close to that of R134a with the advantage of higher values. Generally, the overall performance of the selected mixtures was better than that of R134a. The performance of RM4 was the best in terms of low compressor work and discharge pressure, and high COP, at varying evaporating temperatures.