Demand controlled ventilation (DCV) is a feedback control method to maintain indoor air quality that automatically adjusts the ventilation rate provided to a space in response to changes in conditions such as occupant number or indoor pollutant concentration.
Standard HVAC system design uses fixed airflow rates to calculate the outdoor air (OA) required in a space.
[3] Demand control ventilation is an attractive alternative to standard design in these situations because DCV systems only supply the outdoor airflow necessary to serve the occupants in a space.
[4] Such a control sequence is supported by a pollutant sensor (e.g. carbon dioxide sensor), a variable frequency drive (VFD) on the fan supplying the zone, individual VAV boxes with reheat serving each space in the zone, and airflow measuring stations.
[1] In this proposed system, the HVAC equipment is to run continuously when the space is occupied, then cycle on and off to maintain indoor air quality during inoccupancy.