Modeling the thermal and indoor air quality performance of vertical displacement ventilation systems.

To predict the thermal and indoor air quality performance of vertical displacement ventilation systems using two-zone modeling, it is necessary to account for the different nature of the air flow due to thermal and contaminant mixing within these zones. Two zone modeling of vertical displacement ventilation was performed assuming piston flow in the clean zone, uniform mixing in the dirty zone, and no recirculation between the zones except via heat source plumes. The resulting equations for air change effectiveness and contaminant removal effectiveness more closely match observed vertical displacement ventilation performance than previous studies, especially under non-isothermal conditions with heat sources.