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. The control strategy is mainly intended to reduce the energy use by heating, cooling, and ventilation systems compared to buildings that use open-loop controls with constant ventilation rates.
Common reference standards for ventilation:
Carbon dioxide sensors monitor carbon dioxide levels in a space by strategic placement. The placement of the sensors should be able to provide an accurate representation of the space, usually placed in a return duct or on the wall. As the sensor reads the increasing amount of carbon dioxide levels in a space, the ventilation increases to dilute the levels. When the space is unoccupied, the sensor reads normal levels, and continues to supply the unoccupying rate for airflow. The amount of air supplied is determined by the building owner standards, along with the designer and ASHRAE Standard 62.1.