Comparison of removal effectiveness of mixed versus displacement ventilation during vacuuming session

Abstract

In indoor spaces, floor surfaces constitute reservoirs of active particulate matter that can re-suspend in the macroclimate air. Without efficient removal mechanisms, particles carrying pathogens might compromise occupant's health through direct and indirect contamination. Integrating a proper ventilation system with the choice of appropriate design parameters plays a contributing role in efficient particle removal from the occupied space. In this work, an office space conditioned by either a mixing ventilation (MV) system or a displacement ventilation (DV) system. The aim of this study is to assess and compare the effectiveness of these systems in removing resuspended particles from the indoor space during vacuuming sessions. This was achieved by developing a transient 3D computational fluid dynamics (CFD) model. The model was validated experimentally in a climatic chamber equipped with both MV and DV systems. Good agreement was found between measured and predicted values of particles' concentration with low relative error in the order of 10%. Simulation results showed that the reversed DV configuration provided the best performance by creating effective suction effect at the floor level. The worst performance was provided by the conventional DV system since the upward DV airflow transported the resuspended particles from the floor levels to the upper breathing levels where they spread and contaminated the space. Recommendations were provided for operation of ventilation system during vacuuming session to enhance particle removal.