A numerical study of indoor air quality and thermal comfort under six kinds of air diffusion

Correct air dffusion, as well as the proper quantity of conditioned air, is essential for good air quality and comfortable conditions in forced-ventilation systems. Research has been carried out to study local indoor air quality and thermal comfort in an office under six kinds of air diffusion for summer cooling conditions. The discomfort due to indoor air quality is calculated by the olf and decipol, the units for perceived air quality, and discomfort due to draft is calculated by a comfort equation accounting for turbulence intensity. The distributions of decipol and draft are computed by an airflow computer program based on a low-Reynolds-number k-e model of turbulence. It can be concluded that a fresh air change rate of five is required to maintain less than 20% dissatisfaction due to air quality, even though it is a low-olf office. The percentage of dissatisfied people due to draft is smaller than 15% in the occupied zone in all cases. Outlet location and diffuser characteristics are very important for indoor air quality and thermal comfort.