Investigation of Performance of Low GWP Alternative to R134a in Centrifugal Chiller

Abstract

Abstract Climate change concerns have made the engineering community care more about environmentally friendly working fluids. Currently, the fluid R134a, which has a high global warming potential, is widely used in chiller applications. In this study, several low GWP working fluids, R450A, R513A, R1224yd(Z), and R1234ze(E), are investigated numerically as alternatives to R134a for comparison of their performance under different operating conditions in a centrifugal chiller application. Both the system level performance and component level performance are presented. Increasing the condensing temperature or decreasing the evaporating temperature can lead to a higher compressor power, and thus a lower COP can be obtained. The effect of superheat is trivial for the system level performance. R1224yd(Z) has the lowest value of volumetric capacity, and R513A has a higher value as compared with the baseline. As for retrofit, R1224yd(Z) can only produce $$\\sim 20$$ % of the baseline cooling capacity. As for the compressor size, the R1224yd(Z) value is more than double as compared with the baseline R134a one, and R513A has a compressor size closest to that of the baseline R134a. R450A and R1234z(E) have a slightly higher value in terms of the compressor size. In general, R513A is the best candidate as an R134a alternative.