Theoretical analysis of R1234ze(E), R152a, and R1234ze(E)/R152a mixtures as replacements of R134a in vapor compression system

In this article, R1234ze(E), R152a, and three mixtures M1, M2, and M3 composed of R152a and R1234ze(E) (in the ratio of 60:40, 50:50, and 40:60, by mass, respectively) as drop-in replacements of R134a in vapor compression system were theoretically analyzed. The performance of the vapor compression system was compared in terms of compressor discharge temperature, volumetric cooling capacity, cooling capacity, compressor power consumption, and coefficient of performance. The results showed that R152a had better coefficient of performance as well as nearly equal volumetric cooling capacity and cooling capacity compared to R134a; however, flammable R152a running with high compressor discharge temperature was restricted. Cooling capacity of R1234ze(E) was far lower than that of R134a. M2 was selected as the best alternative for R134a. Volumetric cooling capacity of M2 and R134a was similar so that M2 can be used in R134a vapor compressor system without modifying compressor. Coefficient of performance of M2 was higher than that of R134a by about 3% with 7% lower cooling capacity and 10% lower compressor power consumption. Compressor discharge temperature of M2 was higher than that of R134a by about 2°C–5°C. It was concluded that M2 can primely be an energy conservation and environmental protection alternative to R134a in vapor compression system.