Performance investigation of an ejector expansion refrigeration system working on different alternative refrigerants to R134a

In this paper, the performance characteristics of an ejector-expansion refrigeration cycle using six low GWP alternative refrigerants for R134a are presented through the first and second laws of thermodynamics. The ejector is modelled by assuming a constant-mixing pressure. The investigated refrigerants are compared based on the optimum ejector area ratio, discharge temperature, volumetric cooling capacity (VCC), coefficient of performance (COP) and exergy efficiency (eta(ex)). The drop-in analysis is considered based on the same operating/designing parameters, and the VCC, COP and eta(ex) improvements over the conventional refrigeration cycle are presented. The improvements in COP and VCC are between 7.914%-18.46% and 5.712%-22.82%, respectively, for the investigated range of evaporating and condensing temperatures. These values are higher than that of R134a by about 21% and 16%, respectively. The VCC using R1234yf is very close to R134a with a maximum reduction of 6.5%. Therefore, R1234yf refrigerant appears to be the best alternative to R134a in an ejector-expansion system with an appreciable COP and eta ex devaluation. R152a outperforms R134a in terms of COP and eta ex, thus it is a suitable alternative to R134a except for safety.

Automated summary

This paper presents the performance characteristics of an ejector-expansion refrigeration cycle using six low GWP alternative refrigerants for R134a. The refrigerants are compared based on various parameters such as ejector area ratio, discharge temperature, volumetric cooling capacity, coefficient of performance, and exergy efficiency. The results show that R1234yf and R152a are suitable alternatives to R134a in terms of performance improvement.