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 and ), consis...