Improved energy efficiency for HFC134a domestic refrigerator retrofitted with hydrocarbon mixture (HC290/HC600a) as drop-in substitute

In India, more than 80% of the domestic refrigerators utilize HFC134a as refrigerant, due to its excellent thermodynamic and thermo-physical properties. But, HFC134a has a high global warming potential (GWP) of 1300. This paper presents experimental results of an energy-efficient hydrocarbon (HC) mixture consisting of 45% HC290 and 55% HC600a as a drop-in substitute for HFC134a at various mass charges of 40 g, 50 g, 70 g and 90 g in domestic refrigerators. The experiments were carried out in a 165-litre domestic refrigerator using HFC134a with synthetic oil as lubricant. The performance characteristics such as COP, energy consumption, pull-down time and discharge temperature of HC mixture were measured and compared with those of HFC134a. During the experimentation the ambient temperature was maintained at 30 ± 2°C. The results showed that the 70 g mixture has better COP, lower power consumption, lower pull-down time and lower discharge temperature than HFC134a. The miscibility of synthetic oil with HC refrigerant mixture was also found to be good.