| 摘要 |
PURPOSE:To make it possible to drain water even at the time of a power failure by a method wherein the inlet port and the outlet port of a heat collector are connected to each other through a water draining circuit including a normally closed type solenoid valve and a normally open type solenoid valve arranged parallel to each other. CONSTITUTION:When a circulation pump 4 is energized in response to the outputs of an insolation sensor 6 and a low temperature sensor 7, the water in a heat accumulation tank 2 circulates such that it is supplied to a heat collector 1 from a forward pipe 3a and after being heated by solar heat, it returns to the tank 2 through a backward pipe 3b. In this case, the water draining circuit 14 including the normally closed type solenoid valve 12 and the normally open type solenoid valve 13 connected to circulation pipes 11a and 11b in parallel relationship with each other are connected between the forward pipe 3a and the backward pipe 3b. With the above arrangement, in case where the water in the solar heat utilizing system is drained from the system for the prevention of freezing, the solenoid valve 12 is opened while when an electrical power failure takes place, the solenoid valve 13 is turned OFF to open to thereby drain the water from the system. |
