| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control method of a heat pump water heater capable of controlling the distribution of a refrigerant quantity in a refrigerating cycle used in the heat pump water heater without using a container having a volume to store a refrigerant such as an accumulator, and performing high outside air and high temperature boiling-up operation without increasing the withstand pressure of a refrigerant circuit and elemental components in the heat pump water heater. <P>SOLUTION: This heat pump water heater comprises a refrigerating cycle constituted by connecting a compressor, a radiator, a first expansion valve and an evaporator by refrigerant piping, a branch flow channel branching the refrigerating piping at a place from the radiator to the first expansion valve, and reconnecting the refrigerant piping at a place from the first expansion valve to the evaporator, and a high and low pressure heat exchanger for exchanging heat between a high-pressure refrigerant flowing in the branch flow channel and a low-pressure refrigerant sucked to the compressor, and an opening of the first expansion valve is adjusted to be reduced when discharge pressure is higher than prescribed pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT |
