| 摘要 |
<p>Before defrosting operation, a heat pump type hot water supply device performs high-temperature liquid introducing operation for introducing a high-temperature liquid (including water) into a liquid-refrigerant heat exchanger (5), and during the defrosting operation, the heat pump type hot water supply device performs a bypass circulating operation for circulating, through bypass piping (13), the liquid flowing out of the liquid-refrigerant heat exchanger (5). When the temperature of the liquid flowing into the liquid-refrigerant heat exchanger (5) is not higher than a predetermined level for a predetermined time period, freezing preventing operation for preventing freezing of outgoing piping (3A) leading to the liquid-refrigerant heat exchanger (5) is performed by circulating the liquid, which has flown out of the liquid-refrigerant heat exchanger (5), through the bypass piping (13) at a flow rate less than the flow rate in a boiling operation. After the freezing preventing operation, defrosting operation is performed. Even if the heat pump type hot water supply device is operated in an environment in which the temperature of outside air is very low, stable boiling operation can be performed with water in piping from prevented from freezing.</p> |
