| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the designing cost by calculating a power turning-on time to a heater by using an approximation expression which does not depend on the capacity of a hot water storage tank. SOLUTION: A hot water storage tank 1 is equipped with a supply water temperature measuring sensor 2, a remaining hot water amount level sensor 3, and a temperature sensor 4 which detects the temperature of the remaining hot water in the hot water storage tank 1. Also, an operation device to calculate a power turning-on time to a heater 5 of a specified heat capacity which is provided on the hot water storage tank 1 in order to heat the water in the hot water storage tank 1 to a specified heating temperature, and a timer which starts and ends the power turning-on to the heater based on a power turning-on time obtained by the operation device, are provided. Then, the operation device selects a proper pre-set value in response to a remaining hot water amount level in the hot water storage tank from among pre-set values which are stored in advance, and calculates a power turning-on time by an approximation expression, (a power turning-on time K (min) to the heater)=a constant x (a heating temperature -a supply water temperature-a selected value x (a remaining hot water temperature-the supply water temperature), (in this case, the constant is a numeral value which is not less than 6, and not more than 7).</p> |
