Electrical heat loss control for building perimeter employing plural heaters

A building perimeter heat loss control for a building of the kind having a multiplicity of electrical heaters located around the periphery of the building, adjacent to the outside walls of the building, with the heaters arranged in N zones each including a plurality of heaters along one wall, the perimeter heat loss control comprising:

• N radiant heat responsive heat flow sensors, one for each zone, each heat flow sensor facing the outside wall for its zone in spaced relation thereto, which heat flow sensor generates a wall heat rate signal representative of the rate of heat flow through the wall of its zone;
• N thermal sensors, one for each zone, each thermal sensor positioned adjacent one of the heaters in its zone in spaced relation thereto, which thermal sensor generates a heater heat rate signal representative of the rate of heat generation by the heaters in its zone;
• N comparator means, one for each zone, to which both of the heat rate signals for that zone are supplied, for generating an error signal representative of deviation of the differential between the rate of heat flow through the wall of the rate of heat generation from the heaters in the zone relative to a predetermined preset differential;
• and N power control means, one for each zone, each power control means coupled to the comparator means and the heaters for its zone, for controlling electrical energization of the heaters in its zone in response to the error signal from the comparator means for its zone, increasing or decreasing energization of the heaters in its zone to maintain the error signal approximately at zero.