PURPOSE: To effect heat exchange efficiently and enable to utilize high-temperature hot-water quickly by a method wherein the main body of the hot-water reserving tank is provided with a heat exchanging jacket, the inlet port of heat medium, the outlet port of heat medium and an inflow path switching valve.
CONSTITUTION: When the temperature T1 of the hot-water in the main body 10 of the hot-water reserving tank is lower than a set temperature T2 (for instance the hot-water supplying temperature is 45°C), the inflow path switching valve 18 and an outflow path switching valve 19 are opened to the side of the upper divided jacket 12 by a control signal outputted from a control unit 21 based on the detecting signal of a hot-water temperature detector 20. Consequently, the heat medium is circulated through a pump 8, a heat collector 6, the upper jacket 12 and the pump 8 sequentially. As a result, water in the hot-water reserving tank 10, which is located above the lower rim of the upper divided jacket 12, is only heated concentrically due to heat exchage and, accordingly, the high- temperature hot-water may be obtained quickly. When the temperature T1 of the hot-water in the hot-water reserving tank 10 is higher than the set temperature T2, the inflow path switching valve 18 and the outflow path switching valve 19 are opened to the side of the lower divided jacket 13.
SONE KUNIYOSHI
KODAMA MASUO
