To provide a heat pump water heater having an inexpensive configuration and being easily achieved as a product.
The heat pump water heater is provided with a refrigeration cycle unit 1 constituted by annularly connecting a compressor 2, a heat exchanger 3 for hot water supply, a decompression device 4 and an air heat exchanger 6; an internal heat exchanger 8 for performing heat exchange between a refrigerant from a refrigerant outlet side of the heat exchanger 3 for hot water supply to an inlet side of the decompression device 4 and a refrigerant from a refrigerant outlet side of the air heat exchanger 6 to a suction side of the compressor 2; and a bypass circuit 28 for connecting the refrigerant outlet side of the heat exchanger 3 for hot water supply to the outlet side of the decompression device 4. Water is circulated from a bottom part of a storage tank 11 in the heat exchanger 3 for hot water supply by a boiling-up pump 10, and the water inside the storage tank 11 is heated and stored as hot water. The heat pump water heater is further provided with a heat exchange quantity control means 29 for controlling the heat exchange quantity of the internal heat exchanger 8 based on at least one of flowing-in water temperature of water flowing in the heat exchanger 3 for hot water supply and the outside air temperature. Thus, the heat exchange quantity of the internal heat exchanger 8 can be accurately controlled in a more inexpensive method.
NAKATANI KAZUO
Hiroki Naito
Daisuke Nagano
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