An experimental study on particle resuspension in a room with impinging jet ventilation

Impinging jet ventilation (IJV) is a new ventilation strategy for using in public and industrial buildings with large spaces. It combines advantages of both displacement ventilation (DV) and mixing ventilation (MV). Compared with DV and MV, however, there is a potential risk associated with the IJV system, i.e., particle resuspension from the floor due to the supply air, by which the high momentum jet is directed towards the floor. In the present study, particle concentrations under different supply airflow conditions were measured in an IJV room with indoor pollutant sources. The effect of supply airflow on the resuspension of the deposited particles and the critical supply velocities causing the resuspension for different supply heights and particle sizes were analyzed by using the measured data in a model IJV room. The results show that the critical supply velocity is increased with the increase of supply height and the decrease of particle diameter. Meanwhile, in practical applications, there is little risk of the significantly degrading IAQ induced by particle resuspension via supply airflow in an IJV room. Comparing the resuspension amount caused by the supply airflow of an IJV system with that caused by an occupant walking past, a sharp rise of supply velocity in a short time span in an IJV room will not result in significantly worse IAQ.