Comparative study on energy efficiency of low GWP refrigerants in domestic refrigerators with capacity modulation

Abstract

The ever rapid rise in the number of refrigerators causes a dramatic increase in energy demand and emissions, which represents a small but growing contribution to overall global warming. To mitigate the greenhouse gas emission and energy efficiency, high efficiency linear compressor with capacity modulation and low global warming potential (GWP) refrigerants can be considered for use in refrigerators. This paper presents a comparative study on energy efficiency of R717 (ammonia), R600a (iso-butane), R1234yf and R134a in domestic refrigerators using an oil-free linear compressor. The results show that for given operation conditions, R717 has the highest resonant frequency, power input, cooling capacity while R600a has the lowest. R717 has the potential to be used the proposed linear compressor where there is no contact between the corrosive refrigerant with copper windings. This can significantly improve the energy efficiency ratio (EER) with low cost and minimal environmental impact compared with R134a. R600a requires a larger capacity compressor to achieve the same cooling capacity as R717, R1234yf, and R134a. R1234yf can be considered as an ideal drop-in alternative to R134a for an existing refrigerator because of the similar system performance to R134a.