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Volume Matching Control: Leave the Outdoor Air Damper Wide Open.


pdf icon Volume Matching Control: Leave the Outdoor Air Damper Wide Open. (330 K)
Seem, J. E.; House, J. M.; Klaassen, C. J.

ASHRAE Journal, Vol. 40, No. 2, 58-60, February 1998.

Keywords:

air flow; air handling unit; indoor air quality

Abstract:

Traditional air-handling unit (AHU) control systems link the position of the exhaust air damper, recirculation air damper, and outdoor air damper. This can negatively impact indoor air quality if the exhaust air duct is located near a pollution source. This paper presents a new controls system for VAV AHU's that use volume matching to control the return fan. The New control system links only the position of the exhaust air damper and recirculation air damper. During occupied times, the outdoor air damper is in the fully open position. Simulation laboratory, and field results are presented to compare the new control system and a traditional control system. The results demonstrte that the new control system can prevent air from entering the AHU through the exhaust air damper for conditions that cause the phenomenon with the traditional control system.