Patent ID: 7802438
Filing Date: 2010-09-28
Classification: F24F,G05D

Abstract:
1. A method for controlling an airflow output of a Variable Air Volume (VAV) box in a VAV temperature control system, the method relying on a PID control having a proportional term, an integral term, and a derivative term, the method comprising: measuring room temperature; measuring airflow output of the VAV box; calculating a temperature error between the room temperature and a temperature setpoint; selecting one of at least three distinct regions of operation based at least in part on the temperature error, wherein each region has a predetermined gain set, the regions including a first region when the temperature error exceeds a temperature threshold value, a second region when the temperature error is less than the temperature threshold value but outside of a deadband around the temperature setpoint, and a third region when the temperature error is within the deadband; calculating a PID output using a gain set associated with the selected region; calculating an airflow setpoint using the calculated PID output; and controlling operation of an airflow control damper of the VAV box based on the airflow setpoint and the measured airflow output of the VAV box to control the airflow output of the VAV box.