Experimental study on airflow characteristics and temperature distribution in non-unidirectional cleanrooms for electronic industry

A non-unidirectional airflow cleanroom in electronic industries is prone to be challenged by the wide spread of hot air and contaminants dissipated from process tools to surrounding area, resulting from the collision of the uprising hot air current from the tools and the downward cold air from ceilings. To effectively remove the dissipated heat and maintain the required cleanliness level, we proposed an innovative fan dry coil unit (FDCU) return air system (referring to Fig. 1 and Fig. 2), consisting of ceiling-supply grilles and ceiling-return fans/coils, and demonstrated that the FDCU-return air system can effectively eliminate sub-micron particles from the cleanroom, compared with a conventional ceiling-supply and wall-return air system [1]. This study further investigated the effect of the heat dissipation from the tools on airflow characteristics and temperature distribution in the FDCU-return and wall-return airflow type cleanrooms. Comparisons of velocity vector, turbulence intensity, and temperature distribution between the FDCU-return air system and the conventional wall-return air system were presented. The results showed that the FDCU-return air system can significantly provide better air motion characteristics and temperature distribution in a high heat source case in comparison with the wall-return air system.