| 摘要 |
<p>A control unit has two inputs for connection to respective temperature sensors, and alternative primary and secondary outputs. It comprises a comparison circuit operative to sense the differential between the two input temperatures, switching means to render the primary and secondary outputs alternatively operable, and circuit means for controlling the switching means in dependence on said temperature differential. In a typical solar heating system employing such units a plurality of the units are connected in cascade with the secondary outputs of successive units when operable respectively energizing the next succeeding unit. The units are individually associated with a like plurality of heat stores, each sense the temperatures of a solar energy collector on the one hand and the corresponding heat store on the other hand. The primary output of each unit controls means for transferring heat from the collector to the corresponding store.</p> |
