On-demand ventilation control: a new approach to demand-controlled ventilation.

In this paper a new strategy for controlling ventilation systems is described. The strategy provides fresh air at a flow rate proportional to an estimate of the rate at which occupants generate carbon dioxide. Thus, the ventilation rate is nearly proportional to the occupant density even under transient conditions. Properties of the new strategy are described, and the performance is compared to a concentration regulating strategy in a simulation. The new strategy is shown to respond faster to a change in the occupant density and to keep the concentration at or below a threshold.