Adaptive defrost methods for improving defrosting efficiency of household refrigerator

The defrosting method of the conventional household refrigerator increases freezer temperature during the defrosting operation, and defrosting efficiency reduces because the heater consumes more power than the amount of frost on the surface of the heat exchanger. To solve this problem, three defrost heater control methods, applicable to refrigerators equipped with conduction and radiation heaters, are being proposed. The control methods were classified as a method of simultaneously pulsating two heaters, method of individually pulsating two heaters, and method of step-by-step reduction of radiation heater power. The operation effect of each heater on freezer temperature was analyzed. For the three methods, a heater control optimization process was performed to reduce the temperature increase in the freezer. The power consumed by the heater was minimized and defrosting efficiency improved. The Best performance was observed when two heaters pulsated individually. For this method, the variation in freezer temperature, between before and after the defrost process, was reduced from approximately 11 °C to 5 °C. Additionally, the defrosting efficiency improved by 15%.