Outside air flow controller P.D.Knoespel M.S. "Indoor air quality modeling" 1990 This component controls the flow of outside air based on the pollutant concentration calculated by the type 402 pollutant transport component. Four varieties of flow controller are in this type: a proportional controller, a purge controller, a scheduled purge controller, and a temperature-based economizer controller. For a VAV system, this type also calculates the circulation air flow based on the zone sensible load calculated by the Type 56 Multiple Zone Building Load component. The flow controller takes action based on one of three concentration values from Type 402: the maximum zone return air duct concentration, the mixed return air concentration at the air handling unit inlet, or the supply air concentration. The low limit for outside air flow is the initial value for the outside air flow set in the input deck. This enables setting a base or minimum value for an outside air flow controller and can be used to specify a constant value for outside air flow to model non-controlling ventilation systems. The maximum value for outside air flow is the initial value for circulation flow in the input deck. This value is also the constant circulation flow rate for a VAV system. This type also allows the ventilation system to be started up and shut down once each day at a scheduled time. The times are read from an input file at the beginning of the TRNSYS simulation.