Energy and Indoor Air Quality Analysis of Mixed Air and Displacement Ventilation Systems

Indoor pollutants and particles pose a threat to human health as people spend 90% of their time in indoor spaces. A proper ventilation system should be able to remove indoor air pollutants, reduce particle depositions, at the lowest energy consumption by that system. In this work, particle concentrations and depositions are presented for two ventilation configurations (1) Displacement Ventilation (DV) and (2) the conventional ceiling supply and return. From previous work, energy analysis conducted showed that DV systems supported by chilled ceilings were able to supply cooling and reduce the total energy demand by 53% than the conventional system. Nonetheless, with this energy reduction, the DV system cannot remove as much particles as the conventional ceiling supply and return, causing more particles to deposit which is a problem as deposited particles can resurface again when there are floor disturbances like walking and vacuuming. To benefit from the energy reductions of the DV system supported by the chilled ceiling, a recommendation of a reversed DV system was numerically studied, showing lower particle depositions and concentration.