Multi-vent module-based adaptive ventilation to reduce cross-contamination among indoor occupants

Infectious respiratory diseases are known to have high levels of airborne transmissibility. However, traditional ventilation methods based on perfect mixing often lead to the diffusion of airborne pathogens. A ventilation method that can reduce air mixing is necessary. The ventilation system should also be able to adapt to changes in the use scenario of a given room. For this reason, a new type of ventilation method, referred to as multi-vent module-based adaptive ventilation (MAV), is proposed, and its performance in contaminant diffusion control is evaluated in this study. Computational fluid dynamics (CFD) is applied to investigate the contaminant distribution in a two-desk office with MAV. Tracer gas (CO2) is used to simulate coughed contaminants from an infected person. For three different MAV air distributions (vertical, parallel, and cross mode) and traditional mixing ventilation (MV), the contaminant concentration distributions and contaminant variations in the oronasal areas of the occupants are compared. The results show that MAV results in a smaller contaminant diffusion area and lower contaminant diffusion speed. Furthermore, MAV can reduce the peak contaminant concentrations at the oronasal areas of the occupants to 12% of that of MV. The levels of performance of the three MAV modes are different because of the different airflow patterns that they create. For the tested location of the infected person, the vertical mode has the best performance. The average cumulative inhalation of contaminants in the vertical mode is 23.7% lower than that in the cross mode and 36.5% lower than that in the parallel mode.