Experimental performance evaluation of the dual-evaporator ejector refrigeration system using environmentally friendly refrigerants of R1234ze(E), ND, R515a, R456a, and R516a as a replacement for R134a

Abstract

The main goal of this study was to determine the effects of the entrainment ratio (ER) and condensing temperature (CT) on the performance of a dual evaporator ejector system (DEES) operating on environmentally friendly, low-GWP (Global Warming Potential) refrigerants of R1234ze(E), ND, R515a, R456a, and R516a as a replacement for R134a. The effects of various CTs and ERs on the DEES system performance were evaluated. It was revealed that when the ER increased from 0.1 to 0.9, the Coefficient of Performance (COP) decreased by 26%. Besides, in ejector refrigeration systems, ER values can be changed by using smart technologies, so the desired cooling capacities can be adjusted from DEES. The experiments based on condensing temperature were carried at the ER where the cooling capacities of both evaporators were very close to each other. The results demonstrated that the COP of R1234ze(E) and R515a were higher than that of R134a, and their performance was insufficient in terms of cooling capacity. The total cooling capacities of the DEES with R515a and R1234ze(E) were 11% and 5% lower, respectively, than that of the DEES with R134a, and the COPs of the DEES with R515a and R1234ze(E) were 1% and 9% higher, respectively, than that of the DEES with R134a. Furthermore, the performance parameters obtained from R516a were found to be very close to those of R134a. The COP and cooling capacity of the DEES with R516a were 7% higher and 2% lower, respectively, than that of the DEES with R134a. Finally, considering the GWP values, R516a was the best alternative to R134a among the considered refrigerants.