HEAT PUMP TYPE WATER HEATER

摘要

PURPOSE:To make it possible to shorten a defrosting operation and at the same time, to prevent the lowering of the effective temperature of hot water in a hot water storage tank resulting from the defrosting operation by a method wherein a forward pipe of a water circulating circuit is connected to the lower part of the center of the side surface of the hot water storage tank while a backward pipe is connected to a part near the bottom of the side surface of the tank and a circulation pump is operated even during the defrosting cycle. CONSTITUTION:When a sensor 20 detects frosting during the operation of a heat pump 2, a four-way changeover valve 21 forms the defrosting cycle. In this case, the hot water of a suitable temperature in the hot water storage tank is supplied to a heat exchanger 6 to heat a heat medium by operating continuously the circulation pump 11' so that the defrosting action terminates in an extremely short period of time and the actual heating time for the heat medium is improved sharply. Further, cold water circulating through the hot water storage tank 1 during the defrosting cycle enters the tank from the bottom and the temperature in the tank is not lowered by the cold water. The hot water in the tank 1 is supplied from the bottom during the heating operation of the heat pump and it is possible to heat uniformly the entire region of the tank by convection.