Heating energy implications of utilizing gas-phase air cleaners in buildings’ centralized air handling units

Ventilation systems are a vital component of buildings in order to ensure a healthy and comfortable environment for the occupants. In cold climate regions, ventilation systems are responsible for approximately 30% of building heat losses. In addition to outdoor pollutants (particulate matters, NO_X, etc.), indoor emissions from materials in the form of gas pollutants and emissions from occupants are the principal indoor air quality metrics for securing an acceptable indoor concentration level. Therefore, it is of great interest to study the use of gas-phase air cleaning technologies in low-energy centralized air handling units. This study focused on reducing buildings' heating requirements by recirculating indoor air while maintaining an acceptable indoor air quality level. The heating performance of a typical residential and office building in the central Swedish climate was studied by dynamic building simulations. Indoor air recirculation rates and air changes per hour were the key parameters considered during the simulation of the building's heating demand and indoor gaseous air pollution concentration. We found that introducing indoor air recirculation reduces buildings' heating demand depending on the air change rates per hour. The results show that it is possible to reduce the energy use for heating by less than approximaytely 10% and 20% for residential and office buildings, respectively and maintain acceptable indoor air quality by using gas-phase air cleaning.