DEVELOPMENT OF A COMPRESSOR-LESS REFRIGERATOR WITH A COOKER USING LIQUEFIED PETROLEUM GAS

Abstract

This research was conducted to provide a system capable of utilizing liquefied petroleum gas (LPG) at optimum performance to conserve energy and reduce pollution in the atmosphere in terms of refrigerating items and cooking. It compared the refrigerating properties of LPG with R600 in a refrigerator. The refrigerator used was fabricated to a size of 440 by 510 by 640 mm3 having its external structure made of mild steel, internal structure of aluminum and polystyrene as the insulation material. R600 and LPG were subjected to no load and loading condition while the temperature and pressure were monitored in other to determine the output characteristics. These characteristics includes the work-done, refrigerating capacity and coefficient of performance of the refrigerator. The compressor less refrigerator was achieved by eliminating the compressor and condenser from the system and passing the pressurized LPG through the capillary tube of small internal diameter while the pressure of LPG decreased due to expansion and phase change which occurs in an isenthalpic condition. Due to phase change from liquid to gas, latent heat of evaporization was gained by the liquid refrigerant and the temperature decreased. In this way LPG produced refrigerating effect in the refrigerator and its performance was evaluated through boiling of water on the cooker using LPG. Result from the comparison of R600 and LPG using a vapour compression refrigerator showed that R600 performed better than LPG but LPG could also serve as a good refrigerant in the area of refrigeration. The result from the compressor-less refrigerator performance when subjected to both gas and liquid charging of LPG showed that the liquid charging was more effective as it was able to absorb more latent heat from the refrigerated space and reduced the evaporator temperature. The relationship established between the cooling effect of LPG in the vapour compression refrigerator and in the compressor-less refrigerator was that the compressorless refrigerator had a faster cooling effect in a short duration of time and not requiring the use of electricity to function. Also the increase in the amount of water boiled or increase in the duration of time spent cooking simultaneously increased the cooling rate of the items in the refrigerator. The results obtained from the vapour compression refrigerator and the compressor-less refrigerator, show that LPG is a good refrigerant.