Comparative analysis of refrigerant performance between LPG and R134a under subtropical climate

In this investigation, a series of experiments were conducted to explore the effects of liquefied petroleum gas (LPG) mixture of 60% propane and 40% commercial butane as a drop-in auxiliary for refrigerant R134a in a household refrigerator under subtropical conditions in Bangladesh. Experiments were conducted for both continuous and cycling operating conditions with fixed surrounding air temperature of T-amb = 33 +/- 1 degrees C. Three different sets of varying tube length with variable charging level were considered. The experimental outcome determined - 17.5 degrees C as the optimum freezer air temperature with the use of 65 gm LPG and 4 m capillary tube length. A comparative analysis was conducted for R134a against LPG with charge amount. After replacing refrigerant-R134a with LPG, reduction in pull-down time, discharge temperature, and mass flow rate were found about 2.4%, 17.8%, and 20%, respectively. It can be concluded that LPG is a promising substitute to refrigerant R134a in small-scale domestic refrigerators.