The development of fan filter unit with flow rate feedback control in a cleanroom


A new type of fan filter unit (FFU) systems was developed and evaluated in this study. Capable of controlling the volume airflow rate through a networked feedback control system, the innovative smart FFU systems can supply much more uniform airflow distribution at the exit of the FFUs than common FFUs that are commercially available in the market. The development of the smart FFU was described and the comparisons of exit airflow velocities between the smart FFU and other conventional FFUs were made. The measurements have shown that the velocity uniformity values of the exit airflow of the smart FFUs were less than 5.0% while the conventional FFUs showed the uniformity values in the range of 14.0–28.0%. In addition, the test results in this study demonstrate that smart FFU systems are capable of reaching preset airflow rates relatively quickly, i.e., within 5 s, and maintaining the stable airflow supply to the cleanroom. Author(s): Chen, J.J., C.H. Lan, M.S. Jeng, and T. Xu in Building and Environment, 42:3556-3561.