To provide a heat pump water heater capable of performing boiling-up operation of high efficiency by a heat pump, and boiling up the whole water in a hot water storage tank to a high temperature even when the water of medium temperature of comparatively high temperature, is stored in the hot water storage tank.
This heat pump water heater comprises an antifreeze liquid circulating circuit E formed by piping and connecting an antifreeze liquid circulation pump 22, a water/antifreeze liquid heat exchanger 21 and an air refrigerant heat exchanger 19, and the air refrigerant heat exchanger 19 integrally constitutes a part of the antifreeze liquid circulating circuit E. As the water of medium temperature can be allowed to pass through the water refrigerant heat exchanger 17 after being cooled by the water/antifreeze liquid heat exchanger 21, even when the hot water/water in the hot water storage tank 1 is heated to the water of medium temperature by bath reheating operation or heating operation, the water of low temperature flows to the water refrigerant heat exchanger 17 constantly in boiling-up operation, and the heat pump boiling-up operation of high efficiency can be performed at all times.
Tomoyasu Sakaguchi
Hiroki Naito