| 摘要 |
<p>PURPOSE:To improve the efficiency of the titled apparatus without storing surplus hot water and to miniaturize a hot water storage tank by computing the quantity of hot water for obtaining target hot water and discriminating whether it is sufficient only by a heating element for midnight power and if it is insufficient, it is supplemented by a heating element for ordinary power. CONSTITUTION:The temperature of lower water is detected by lower temperature detecting means of a hot water storage tank whereby the necessary quantity of heat requirement and boil-up temperature are computed by computing means 14. A necessary quantity of heating is computed from a difference between the required quantity of heat and the boil-up temperature, and whether heat can be generated within a midnight power supply zone, is discriminated. In a case where heating due to ordinary power is required, power is supplied to a second heating element 9. Further, it is possible to set a target hot water temperature and a target hot water quantity by input means 32. It is also possible to provide means to set the power supply to the second heating element 9.</p> |
