| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem where, when a conventional heat pump water heater is made responsive to a heat pump water heater for a cold region using carbon dioxide as a cooling medium, a high-pressure side cooling medium circulation quantity cannot be obtained by gas injection, and heating capability is lowered. <P>SOLUTION: This heat pump water heater is provided with: a refrigeration cycle composed by annularly connecting a two-stage compressor 4, a radiator 5 for carrying out heat-exchange between a cooling medium and a load-side medium circulating a water heater circuit 12, an expansion valve 6, and an evaporator 7; a high/low pressure heat exchanger 8 for carrying out heat exchange between the cooling medium flowing between the radiator 5 and the expansion valve 6, and the cooling medium flowing between the evaporator 7 and the two-stage compressor 4; an injection circuit 9 branched from a part between the radiator 5 and the high/lower pressure heat exchanger 8 and connected to an intermediate connection part 2; and an expansion valve 10 for the injection circuit arranged in the injection circuit 9. The heat pump water heater is structured to set a ratio of an excluded volume of a high stage-side compression mechanism 3 to an excluded volume of a low stage-side compression mechanism 1 to 0.6-0.8. <P>COPYRIGHT: (C)2008,JPO&INPIT |
