Novel Design and Performance of Domestic Refrigerators

Domestic refrigerators are significant users of energy due to their continuous operation. The compressor is the single largest energy consumer in a refrigeration appliance and its selection is fundamental to achieve a higher system performance. This paper focuses on the compressor in the domestic refrigerator and specifically, compressor performance at refrigerator typical operating conditions has been investigated. An analysis of the compressor isentropic efficiency for various compressor displacements (4cc to 11cc) was carried out. A theoretical model for a refrigerator was developed to investigate the influence of compressor displacement, evaporating temperature and ambient temperature on system efficiency. The results have shown that the energy consumption of refrigerators is strongly influenced by ambient temperature and larger compressors are significantly more efficient. An energy reduction of 17% was obtained by replacing the smaller 4cc compressor by an 8cc model in the system considered. The excess cooling capacity produced by large compressors can be stored as thermal cooling energy in a phase change material and used to increase the refrigerator autonomy without power supply.