Experimental Study of Energy Consumption by Removing the Defrost Heating Element in Domestic Vapor Compression Refrigeration Cycles

In this article, we optimize the energy consumption in the defrost cycle of a domestic refrigerator-freezer. In this refrigerator-freezer, the parallel two-stage compression (PTC) cycle is used. These systems have an automatic defrost mode and are designed so that the thaw from moisture on the evaporators is melted by the electronic board command . The heating elements are 220 V and their use for defrosting consumes 145 W of power, which causes a lot of heat and power consumption and increases energy consumption. In this study, in a domestic compression refrigerator-freezer, we use a Brushless direct current (BLDC) fan to defrost the fresh food compartment evaporator (FFCE) when the compressor shuts down, which is automatically set at a preset time and frequency. In this type of domestic refrigerator-freezer, due to the low temperature in the evaporator of the FFCE and its small volume, the heating element can be removed to defrost in the FFCE. Defrosting in the FFCE section will be done by the evaporator fan. The equipment used in the refrigerator-freezer cycle includes variable speed compressor, condenser, dryer, three-way valve, FFCE, and Freezer compartment evaporator (FZCE). R-600a refrigerant is used in the refrigerator-freezer cycle. The refrigerator-freezer is tested in a laboratory refrigerator-freezer with an ambient temperature of 25 °C, in accordance with international standards (IEC 62552). The energy consumption of this refrigerator-freezer according to the relevant standard is equal to 320 kWh/ year, which has an A + + energy consumption grade.