Energy and IAQ impacts of CO2-based demand-controlled ventilation

This study examines the effectiveness of using carbon dioxide-based, demand-controlled ventilation (DCV) to provide adequate indoor air quality with minimum energy use. A detailed building energy analysis program (ENERPASS) was combined with a contaminant-level prediction program (CONTAM87) to perform the analysis. The combined program was used to evaluate the annual heating and cooling energy consumption and carbon dioxide and formaldehyde concentrations. The assessment was made on a mid-sized commercial building designed to comply with ASHRAE Standard 90.1. Three separate heating, ventilating, and air-conditioning (HVAC) systems were studied: single zone (i.e., multiple roof-top units), multizone, and variable air volume (VAV). The simulations were made for five ventilation control strategies: fixed ventilation; building return air controlled to 1,000 ppm and 800 ppm; floor return air controlled to 1,000 ppm; and each zone controlled to 1,000 ppm.