Under controlled conditions in an environmental chamber, 24 experiments were performed to compare the ability of a Variable-Air-Volume/Bypass Filtration System(VAV/BPFS) to remove indoor pollutants and to conserve energy with the ability of conventional Variable Air Volume(VAV) system. The specific conclusions of this paper were; first, the VAV/BPFS was more efficient than the VAV system in removing particulate matter, TVOC, and target VOCs. The total effective removal rate of PM for the VAV/BPFS was two times as high as that of the VAV system. The total effective removal rate of TVOC for the VAV/BPFS was 20 percent higher than that of the VAV system. Also each target VOC concentration was reduced by using the VAV/BPFS. Second, clean air delivery rate was increased by using VAV/BPFS due to additional filtration rate. Otherwise, the VAV/BPFS decreased outdoor supply air rate above 25 percent relative to the rate of VAV system. Third, total energy consumption by the VAV/BPFS was lower than that of the VAV system during the period with indoor thermal load, occupied time. The energy saving of the VAV/BPFS ranged from 11 to 16 percent. The VAV/BPFS improves indoor air quality more efficiently than the VAV system, and it reduced energy consumption. Retrofitting the VAV system with the VAV/BPFS was easy. The use of VAV/BPFS is, therefore, recommended for buildings with VAV system as well as for buildings at designing stage.

The oil crisis of the 1970s and the rise in oil prices motivated people to implement energy conservation strategies. Buildings were fitted with additional insulation and reduced ventilation rates. The reduction of mechanical and natural ventilation rate led to increases in indoor pollutant concentrations which resulted in increased health risks from indoor exposure to pollutants. The variable-air-volume/bypass filtration system(VAV/BPFS) is a variation of the conventional VAV systems, The VAV/BPFS is an electronically controlled system that provides cost-effective thermal comfort and acceptable indoor air quality. Under controlled conditions in a chamber, a series experiments were performed to compare the ability of a VAV/BPFS to remove indoor aerosol concentration and to reduce energy consumption with that ability of conventional VAV system. Results show that the VAV/BPFS increases the effective ventilation rate and removes indoor air pollutant, and maintains acceptable indoor air quality without sacrificing energy consumption.