Variable air volume system control

摘要

An electronic control for positioning the damper in the air supply duct of a variable air volume system having a motor to open and close the damper, a thermostat circuit sensing temperature in a conditioned space and developing a voltage signal indicative of the temperature in the space relative to the thermostat setting, an electronic air flow sensing circuit sensing air flow into the conditioned space and developing a voltage signal indicative of air velocity, a circuit processes both signals and applies the difference between them to an electronic variable timer which effectively varies the motor speed (by varying the motor duty cycle) so said damper is moved slower as equilibrium between the space temperature and the set point of the thermostat is approached. The same voltage signals are fed into a logic circuit to determine the direction of motor rotation to determine whether the damper opens or closes.