In recent years, the demand for higher cleanliness and air quality control of the indoor environment is increasing especially during the manufacturing process. Although different design standards and codes were adapted worldwide, the air flow pattern analysis still dominates the design process. The parameters affecting the design process were cross-examined, including the air change rate, clean room sizes and layout, air supply and exhaust ports layout, unbalanced supply and exhaust air volume (QR=1.2QS), until system optimization is achieved. Furthermore, FFU system with 0.46m/s air speed was identified to be appropriate for injection module designs. In order not to increase manufacturing cost, the FFU can be design with three-fiered speed control to provide energy efficiency with space flexibility. However, in low-speed operation, the slightly positive pressure cannot be maintained properly and should be avoided to operate in unconditioned rooms.

In various industries, specialized filters with activated carbon are used for adsorbing mercury from air-flows. MRT has eight such Activated CarbonFilters (ACFs) in one of their devices. The main purpose of research is tostudy the flow in the ACF filter and suggest a mathematical model for the complete system through which an improved design can be found.Simulation of a single ACF illustrates how the current system’s air flow does not cover the whole filter leaving part of the carbon bed unused forthe adsorption. This is validated by experimental data. A theoretical studybased on a mathematical model is made and the improved air flow pattern of a re-designed ACF is presented. An additional improvement is that byswitching inlet and outlet the usable time of the filters is prolonged.