Improvement on Energy Consumption of Household Refrigerator

In this work, a household refrigerator was fabricated and improvement on its energy consumption, by means of a composite insulation, was examined. The refrigerator was constructed with a cooler, which is made of 1.7 mm-thick plastic as its outer insulation. The outer, middle, and inner insulations of the cooler serve as the outer, middle, and inner walls, respectively, of the refrigerator. The inner insulation is 0.6mm-thick polystyrene and the middle insulation was originally 60mm-thick styro foam. After the initial experiment with the styro foam, it (the styro foam) was removed and replaced in succession with other insulations, namely rigid polyurethane foam, expanded polyurethane foam, fibre glass, and composite insulations, for which the experiments were successively repeated. The results indicated that the refrigerator with composite insulation consumed the least amount of energy of 0.195 kWh/day and it also had the lowest value of heat flux of 0.130 W/m2. The results obtained from the experiments on instantaneous heat flux and instantaneous temperature further revealed that of all the insulations considered in the present work, the refrigerator with composite insulation has the highest capacity to retain heat in the refrigerating chamber of the refrigerator. The inference is that the use of composite insulation can reduce energy consumption of a household refrigerator.