| 摘要 |
PURPOSE:To enhabce the efficiency in collecting solar heat, by a method wherein the amount of sunshine is detected, and a pump is controlled to operate in a condition as close as possible to a continuous operation. CONSTITUTION:The water heater is a forced circulation type water heater utilizing solar heat, wherein a photo-switch 5 is provided to operate the pump 4 when the illuminance of the sunshine supplied to a collector 2 becomes not lower than a predetermined value, and to stop the pump 4 when said illuminance becomes not higher than a predetermined value. Accordingly, whenever the amount of sundhine required to heat a heat-transmitting medium passed through the collector 2 is available, the pump 4 is operated so that the solar heat can be recovered. Therefore, it is possible to obercome the conventional problem that the recovery of the solar heat is delayed due to stoppage of the pump 4 when the amount of sunshine is sufficient and that the efficiency in utilizing the solar heat is lowered due to the release of heat from the collector 2 in such an occasion, and accordingly, the efficiency in collecting heat can be enhanced. In addition, since the pump 4 is controlled in accordance with the irradiation of the sunshine, the construction of the circuit becomes extremely simple. |
