| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater capable of effectively using the capacity of a hot water storage tank by storing high-temperature hot water to a lower part of the hot water storage tank with a low power consumption without causing an abnormal temperature rise of a compressor. <P>SOLUTION: This heat pump water heater comprises a refrigerant main circuit formed by successively connecting at least a compressor 31, a hot water supplying heat exchanger 32, a main throttle device 33 and an evaporator 34, a hot water circuit connected to the hot water supplying heat exchanger 32, a refrigerant sub-circuit bypassing the main throttle device 33, and a control device 42. The refrigerant sub-circuit is adapted to serially connect an opening and closing valve 48 to a sub-throttle device 40. Even if incoming water temperature is raised when a boiling-up operation gets close to completion, the refrigerant at the outlet of the heat exchanger 32 is bypassed to the low-pressure side of the inlet of the evaporator 34. Therefore, hot water to be supplied can be easily heated to a high temperature while reducing the discharge pressure or discharge temperature of the compressor 31, and the heat pump can be safely and efficiently operated. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
