| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the load of a compressor in the start of a freeze proofing operation in a heat pump type water heater. <P>SOLUTION: The heat pump type water heater comprises a by-pass circuit 16 for connecting the outlet side of the compressor 10 to the inlet side of an evaporator 13 and an on-off valve 17 for opening and closing the by-pass circuit 16. By opening the on-off valve 17 in the finish of the freeze proofing operation, a high-temperature high-pressure refrigerant on the outlet side of the compressor 10 flows directly (namely, without a water refrigerant heat exchanger 11 or the like) to the evaporator 13 side via the by-pass circuit 16 in the finish of the freeze proofing operation. Thus, dryness can be increased by increasing the temperature and pressure of the refrigerant existing in the evaporator 13 or a vapor/liquid separator 14. Therefore, liquid compression is avoided in the start of the freeze proofing operation, and the load of the compressor can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
