OR-10-026 -- A New Reverse Cycle Defrost Design Concept for Refrigerators PDF

Refrigerators have been becoming more energy efficient in recent years. However, there is little research work on refrigerator defrosting. Refrigerators generally still use electrical resistance heating elements for defrost. In Asia, particularly in Japan and Taiwan, a lot of refrigerator condensers are attached to the refrigerator side panels, with heat dissipation through the panels. This design saves refrigerator space, but is not very energy efficient. Applying a typical heat pump type cycle reversal for defrosting would cause the condenser panels to become cold, and moisture might condense on the surface of the side panels and run down to the floor. A novel reverse cycle system was designed to completely by-pass the condenser, thus avoiding moisture condensation on the side panels. Qualitative laboratory test data indicated that the reverse cycle defrosting concept worked as expected, and it was found to be more energy efficient than the conventional direct electric heating defrost method.

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