Demand-controlled ventilation
Illustrated Guide to Ventilation (BG 2/2009), compiled by Kevin Pennycook and published by BSRIA in 2009, states in relation to demand-controlled ventilation: ‘Where a zone within a building is supplied with a fixed ventilation rate and the level of occupancy vary greatly the potential exists for the use of demand-controlled ventilation. This approach varies the ventilation rate in relation to the level of occupancy in a specific zone. This allows for reductions in energy consumption during periods of low occupancy. Potential applications for demand-controlled ventilation include meeting or conference rooms and lecture halls along with general office accommodation if occupancy levels are variable. The most common method of inferring occupancy levels is through the use of CO2 sensors. Occupants expel metabolic CO2; by measuring CO2 within a building zone levels of occupancy can be inferred and the ventilation rate varied accordingly. The relationship between CO2 level and ventilation rate can be set depending on the desired level of indoor air quality.’
--BSRIA
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