Although many laboratory cleanroom air distribution systems have unique arrangements, some features are common. In general, medium pressure duct designs are not applicable to cleanrooms. Typically, the area above the cleanroom ceiling is an equalizing plenum, supplying clean air from high-performance filters. Process and personnel heat and contaminants are removed as the air flows through the room and exits through a grated floor. An air passageway under the floor brings the air back to the fan(s), which return it to the plenum to complete the cycle. Heat is removed from this air stream by an air conditioner positioned in the return duct. Before being mixed into the clean room supply air, make-up air is also conditioned by this air conditioner or a second one. [Kruse, 1991; Takenami et al., 1994]
Large ducts and plenums reduce power consumption but require large spaces. High-velocity duct systems are not the most energy efficient because even slight increases in pressure drops translate into large energy costs. The configuration of air recirculation, heat removal, and make-up air conditioning is highly sensitive to climate, local energy costs, and the class of the cleanroom. Extensive analyses are recommended to optimize these system interactions for each installation. [Kruse, 1991; Takenami et al., 1994]
Vertical laminar flow cleanroom
Horizontal laminar flow cleanroom
