| 摘要 |
<p>A method of controlling a space heating system having a plurality of electrical resistance heaters includes the steps of computing the aggregate number of resistance heaters required to be energized to raise the actual temperature within a space to a set point temperature. This aggregate number may have integer and fractional components. One of the resistance heaters, denominated a controlled heater, is adapted both for continuous energization or for modulated control by intermittent energization. A group of second resistance heaters is adapted for continuous, staged energization, this group including a number of heaters equal to the integer component. Energization of the heaters comprising this group is preferably sequential after the lapse of a preselected interstage time delay between energization of the controlled heater and the first heater of the group. Similarly, time delays will be interposed between the time of energization of the first heater of the group and the times of energization of succeeding heaters in the group. The aggregate number is repetitively recomputed, and the heaters comprising the group of second heaters are successively energized or de-energized in a quantity equal to the integer component. The controlled heater is energized for an average time which is equal to the fractional component. As the actual temperature approaches the set point temperature such that the integer component becomes zero, all heaters in the group are de-energized and when the actual temperature is equal to the set point temperature, the controlled heater is also de-energized.</p> |
