Heat pump water heater with auxiliary heat source

摘要

PROBLEM TO BE SOLVED: To provide such a heat pump water heater with an auxiliary heat source machine as can reduce a running cost.SOLUTION: A heat pump water heater with an auxiliary heat source machine performs a hot water storage by a heat pump operation in accordance with the prediction of a hot-water supply use, and the hot water can be stored at least at a first preset temperature and at a second preset higher temperature. In a hot water storage operation to a bathtub and a hot water feeding operation, a target hot water storage heat quantity and the hot water feeding time are set from the prediction of the hot water use. In the case where the target hot water storage heat quantity is less than the maximum hot water storage heat quantity at the first preset temperature, the hot water storage operation is performed at the first preset temperature. In the case where the target hot water storage heat quantity is more than the maximum hot water storage heat quantity at the first preset temperature, the COP of the heat pump operation is calculated. In the case where the COP is at or more than a predetermined value, the hot water storage operation and a hot water supply operation are so performed a plurality of times before the hot water feeding time as to reach a target hot water storage heat quantity. In the case where the COP is less than a predetermined value, the hot water storage operation is performed to reach the target hot water storage heat quantity at the second preset temperature.SELECTED DRAWING: Figure 3