Impact of demand controlled ventilation on indoor air quality, ventilation effectiveness and energy efficiency in a school building

Demand controlled ventilation (DCV) can reduce the energy use significantly compared to a constant air volume (CAV) system. However, there is still uncertainty about the indoor air quality (IAQ) and the ventilation effectiveness of the room. Aim of this paper is to assess the IAQ, ventilation effectiveness, local thermal comfort and energy efficiency of a DCV system in a school building. Measurements of CO2 concentrations and power consumption of the fan are conducted in two adjacent classrooms during two weeks in winter. In addition, one day measurements of air velocity in the room are carried out. The median CO2 concentration measured for all sensor positions are in the range of 850-950 ppm. The ventilation effectiveness calculated is 0,89 to 0,99. The total energy demand for the fan is reduced with 24% compared to a CAV, by controlling the air flow rate using the CO2 concentration.status: accepte