Contaminant behavior and distribution in mechanically ventilated multi-zone building

Abstract

When HVAC systems are not the source of indoor air pollution, they influence movement of contaminants within multi-zone buildings through air redistribution by ducted networks or by pressure differentials across zonal partitions. Current design, operation and maintenance procedures of HVAC systems have been unable to deal with this problem effectively and contemporary issues of weaponized contaminants emerges as a new threat to the health and lives of occupants. The objective of this research is to investigate the behavior and distribution of indoor air contaminants in mechanically ventilated multi-zone buildings. This was achieved through simulations of a theoretical multi-zone buildings and a Case Study. Influencing parameters such as Outdoor Air Fraction; Pressurization; Filter Efficiency; Filter Location; Local Exhaust Ventilation; Source Location and Inter-zonal Air Flow were investigated individually and collectively. Their singular effects on the migration phenomena were weighted and ranked, in order to give an insight into their quantitative impacts. Results showed that even with multiple Air Handling Units, parameters have varying degrees of influence depending on the architectural and mechanical configuration of the building, inter-zonal airflow, source location, filtration and exhausting. Guidelines in the form of recommendations were suggested to assist designers and building operators in retrofitting existing buildings or in future designs of buildings.