Comparative performance analysis of R600a and R436a as an alternative of R134a refrigerant in a domestic refrigerator

Abstract

R134a is the most widely used refrigerant in domestic refrigerators. R134a is a Hydrofluorocarbon (HFC) with high GWP of 1430 and hence, it must be phase out soon under the Kyoto protocol. Hydrocarbon (HC) refrigerants have zero ODP and very low GWP. In the present work, an experimental investigation has been made with HC refrigerant R600a (isobutane) and Hydrocarbon mixture (HCM) refrigerant R436a (composed of R290 and R600a in the ratio of 54:46 by weight) as an alternative to R134a refrigerant in 170 L domestic refrigerator. The performance characteristics such as coefficient of performance (COP), energy consumption, pull down time, discharge temperature, pressure ratio and evaporator inlet temperature of R600a and R436a were compared with those of R134a. The system was modified by replacing HFC compressor with HC compressor and using optimized capillary. In the modified system, for 45g of R436a, the power consumption reduces by 41.66% as compared to R134a in original system also it reduces by 15.66% than optimized charge of R600a in modified system. COP for optimized charge of R436a with modified system increases by 60.25% than R134a and 27.11% R600a.Pull down time for R436a also reduces considerably than R134a and R600a. The overall performance has proved that the R436a refrigerant could be the best long term alternative to phase out R134a.