A Numerical Investigation on the Influence of a Combined Desk Local Exhaust Ventilation System on COVID-19 Dispersion and Indoor Thermal Comfort in Classrooms

Providing a healthy environment in schools, particularly during a global pandemic, is crucial to saving occupants’ lives and reducing infection rates. This paper proposes a novel desk local exhaust ventilation (DLEV) system that uses a local exhaust diffuser integrated into a classroom desk. The performance of the system in providing a healthy and comfortable indoor thermal environment and reducing the risk of COVID-19 infection was assessed numerically. The assessment combined indoor thermal comfort indices and the bioaerosol dispersion behavior of airborne particles. The study was completed in a typical classroom layout, in which the results show that the DLEV system meets thermal comfort requirements by maintaining the gradients of vertical temperature within an acceptable range. The DLEV system increases the air motion in the breathing zone while keeping it within the recommended range of <0.25 m/s. The PMV and PPD indices are within recommended comfort levels for all but three occupants. Most notably, the DLEV system substantially reduces the concentration of bioaerosols, especially around the occupants’ head. This system works by capturing and removing the virus-rich aerosols exhaled by infected subjects before they disperse in the classroom. This lowers the risk of infection among healthy subjects. These findings confirm the effectiveness of the DLEV system in enhancing both thermal comfort and indoor air quality, making it suitable for environments where specific goals regarding occupants’ health and thermal management are required, such as in a classroom of healthy and infected subjects.