ZONE CONTROL SYSTEM PROVIDING SYNCHRONIZATION OF SYSTEM OPERATION WITH THE ZONE OF GREATEST DEMAND

摘要

A zone control system uses signals from a plurality of separate zone thermostats to determine the zone of greatest thermal load or demand. Specifically, the on-time of each thermostat signal is integrated with respect to time so that the zone of greatest demand can be determined. The thermostat signal from the zone of greatest demand is used to control a duct damper between that zone and a heating/cooling plant. To synchronize the opening of the other zone duct dampers with the duct damper of the zone of greatest demand, the length of each of the on-periods of the thermostats in the other zones is first converted to the cycle rate of the zone of greatest demand thermostat since the other thermostats are operating at different duty cycles. A microprocessor-based master zone controller uses these converted on signals to control respective zone duct dampers in the other zones coincident with the start of the thermostat on-period of the zone of greatest demand. Thus, the duty cycle of these duct control signals is equal to the duty cycles of the thermostats in the corresponding zones, but the control signals have time periods equal to that of the control signal for the zone of greatest demand.