| 摘要 |
PURPOSE:To prevent a heat-collecting pump from being burned, by providing a controller for changing over to commercial electric power in accordance with the output of a solar cell, in a solar heat collector wherein a heat-collecting pump is driven by a solar cell. CONSTITUTION:A relay switch 5 is closed to constitute a circuit comprises of the solar cell 1 and a dummy resistor 3, and the electric power generated by the solar cell 1 is monitored by an electric energy meter 4. When the electric power generated is not lower than the first set point (namely, when electric power sufficient for starting the heat-collecting pump is generated), the relay switch 5 is opened, while a relay switch 6 is closed to connect the solar cell 1 and the heat-collecting pump 2 to each other. The pump 2 started is constantly monitored through the electric energy meter 4, and when the electric power generated becomes not higher than the second set point, the relay switch 6 is opened to stop the operation of the pump 2 by the solar cell 1. Simultaneously, the relay switch 5 is closed, and it is monitored that the electric power generated by the solar cell 1 again reaches a value sufficient for operating the pump 2. |
