Design of LPG Refrigeration System and Comparative Energy Analysis with Domestic Refrigerator

Supply of continuous electricity is still not available in several areas of the country and the world. At such places, this work will be helpful for refrigreration of food, medicines, etc... In this work we have investigated the performance of a refrigerator based on liquefied petroleum gas (LPG) refrigerant since LPG is locally available and is easy to transport anywhere. LPG is a byproduct in petroleum refineries and comprises of 24.4% propane, 56.4% butane and 17.2% isobutene which have very low boiling point (lower than 0 oC). The use of LPG for refrigeration purpose can be environment friendly since it has no ozone depletion potential (ODP). Usually LPG is used as a fuel for cooking food in houses, restraurants, hotels, etc.. and the combustion products of LPG are CO2 and H2O. In this project we have designed and analysed a refrigerator using LPG as refrigerant. LPG is available in cylinders at high pressure. When this high pressure LPG is passed through the capillary tube of small internal diameter, the pressure of LPG is dropped due to expansion and phase change of LPG occurs in an isoenthalpic process. Due to phase change from liquid to gas latent heat is gained by the liquid refrigerant and the temperature drops. In this way LPG can produce refrigerating effect for a confined space. From experimental investigations, we have found that the COP of a refrigerator which uses LPG is higher than a domestic refrigerator.