Experimental studies of isobutane (R600a) as the refrigerant in domestic refrigeration system

This paper presents an experimental study on the performance of a domestic vapor-compression refrigeration system with isobutane (R600a) as the refrigerant. The input power of the compressor varied between 230 and 300 W, while the amount of the charged refrigerant was about 150 g. The expansion and heat transfer components of the system were capillary tubes and plate heat exchangers, respectively. The refrigeration temperatures were set at about 4 and −10 °C to simulate the situations of the cold storage and the freezing applications. Both normal and extreme conditions were investigated in this work. In the cold storage application, two capillary tubes in parallel gave better performances than a single tube. The proper sizes of the tube are between 4 and 4.5 m in length, and 0.7 mm in internal diameter in the cold storage application, while in the freezing application they are between 4.5 and 5 m in length, and 0.6 mm in internal diameter. The coefficients of performance of the system lie between 1.2 and 4.5 in the cold storage application and between 0.8 and 3.5 in the freezing application, which are comparable with those of the system with R-12 and R-22 as the refrigerant. In general, the refrigeration capacity increases with the refrigeration loads.