demand control ventilation

Indoor carbon dioxide (CO2) concentrations have played a role in discussions of ventilation and indoor air quality (IAQ) since the 18th century. Those discussions have evolved over the years to focus on the impacts of CO2 concentrations on building occupants, how these concentrations relate to occupant perception of bioeffluents, the use of indoor CO2 concentrations to estimate ventilation rates, and CO2–based demand control ventilation. This paper reviews how indoor CO2 has been dealt with in ventilation and IAQ standards in the context of these issues.

Most HVAC systems are designed to supply air based on assumed (usually maximal) rather than actual occupancy, therefore often resulting in over-ventilation. The concept and theories of demand-controlled ventilation (DCV), which are to find better ventilation strategies according to actual occupancy, have been developed for more than two decades and have been applied to many situations. However, a certain type of room (i.e. short-term occupied room) seems to have been neglected in the literature of DCV.

In the light of ever increasing oil prices and rapidly depleting fossil fuel resources, energyconservation strategies in buildings become popular and necessary design goals. However, it is important to note that resulting poor ventilation in the occupied zones at part-load operating conditions or even unanticipated peak-load conditions due to a different occupancy pattern can often lead to major problems associated with poor Indoor Air Quality (IAQ).

The paper presents part of the outcomes from the project set up by the Polish Committee forScientific Research and devoted to development of the recommended control strategies forDemand Controlled Ventilation (DCV) systems in Poland. The performance of both differentCO2-based occupancy detection algorithms for online demand controlled ventilation systemsand different methods of digital filtration of signals have been studied.

In France, ventilation in new residential buildings must be designed and dimensioned according to the Health regulation (Arrêté du 24 mars 1982) which is basically based on required extract air flow rates. Two points are to be noticed : 1) The extract flo