Hydrocarbon Blends and Blends of HFC-134a-HC600a as Drop In Refrigerants for Small Capacity Commercial Refrigeration Appliance - An Experimental Study

The awareness to protect the environment from the harmful effects of CFCs has motivated the refrigeration scientists and engineers to study alternative refrigerants to replace the CFCs even in the existing units. This paper presents a thermodynamic study of hydrocarbon blends (Propane/lsobutane) and blends of HFC-134a-HC-600a as a possible "drop-in" (some electrical component to be changed to make the appliance safe) substitute to CFC-12. Thermodynamic properties of these mixtures needed for the analysis have been computed using "Refprop". An extensive experimental work has been carried out to evaluate the performance of the proposed blends for small capacity commercial refrigeration appliances such as bottle coolers. The quantity of refrigerant charge has been determined experimentally for the minimum energy consumption for the best composition. The results show that the hydrocarbon blend with 50 percent by mass of isobutane and HFC-134a-HC-600a mixture are potential drop-in candidates. The hydrocarbon blend consumes about 12% less energy in comparison to HFC-134a-HC-600a. However, these refrigerants are flammable which require some changes in electrical components to make the appliance safe.