| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater capable of sufficiently boiling up the water within a time frame without generating system-down caused by an over-load state in a case when an operating frequency of a compressor is changed by the change in watering temperature, or without impairing of the reliability of the compressor caused by high pressure, liquid-back and high and low pressure difference. <P>SOLUTION: This heat pump water heater wherein the operating frequency of the compressor is variable, comprises an outside air temperature detecting means for detecting the outside air temperature, a watering temperature detecting means for detecting the watering temperature to be supplied to a heat exchanger for supplying the hot water, and a frequency determining means for determining the operating frequency of the compressor. The frequency determining means determines a target frequency of the compressor on the basis of the outside air temperature detected by the outside air temperature detecting means and the watering temperature detected by the watering temperature detecting means, and the frequency of the compressor is raised in stages by every specific time when the target frequency of the compressor is increased by the change in the watering temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
