| 摘要 |
PURPOSE:To moderate the peak of electric power load, by a method wherein a required period of time of supplying electric power to a heating element is calculated on the basis of a set point of hot water amount and a detected value of feed water temperature, and a power-supplying peration is started by a timer so that said period of time is fully elapsed at the time of finishing a night power supplying operation. CONSTITUTION:A calculator 7 calculates the required period of time of supplying power through the formula (T-t)XV, where V is a set point of the amount of hot water used which is set for the next day by a hot water amount setting means 5, (t) is the temperature value detected by a feed water temperature sensor 6, and T is the hot water temperature. The timer 8 starts the supply of power to the heating element 9 so that the required power-supplying period of time is fully elapsed at the time of finishing the night power supplying operation. As a result, the amount of hot water left unused is reduced, and a larger amount of hot water is stored at a temperature of not higher than that in a heated-up condition, and accordingly, heat loss due to radiation can be reduced. In addition, since power is supplied in a later part of the night power supplying hour, the peak of electric power load can be moderated, and power-transmitting efficiency can be enhanced. |
