| 摘要 |
PROBLEM TO BE SOLVED: To suppress wasteful energy consumption when hot water is stored in a hot water storage tank more than necessary.SOLUTION: A boiling control unit 123, when a residual hot water amount in a hot water storage tank 11 becomes equal to or less than a lower limit level, starts a boiling operation for heating hot water stored at a lower part of the hot water storage tank 11 and returning it to an upper part of the hot water storage tank 11 by operating a tank circulation pump 66 and a heat pump 51, and when the hot water amount stored in the hot water storage tank 11 becomes equal to or greater than a boiling completion level, finishes the boiling operation. A boiling completion level setting unit 127, at the start of the boiling operation, sets the boiling completion level according to a difference between an actual hot water tapping accumulated value in a predetermined time zone and a total hot water tapping amount index value (an average value or a maximum value of the total hot water tapping amount in the predetermined time zone during the past 7 days).SELECTED DRAWING: Figure 1 |
