Numerical evaluation of the effect of air distribution system and location on performance of a portable air cleaner

Indoor air quality (IAQ) has been an important issue in air conditioning researches. Ventilation and air cleaning are two approaches to improve the air quality in closed spaces. Portable air cleaners (PACs) are devices, which are very efficient in removing air pollutants and recently have gained much attention in IAQ applications. In this study, a numerical study was developed to investigate the gas removal of a portable air cleaner under different air distribution systems. SF6 was used as a tracer gas to model the dispersion of gaseous pollutants in a simulated office involving a thermal manikin as an occupant. Clean air delivery rate (CADR) exposure reduction effectiveness and age of air are the concepts that were used to evaluate the air cleaner performance. Simulation results showed that the cleaner was more efficient under mixing and the wall-mounted system and did not perform well under under-floor air distribution system (UFAD) system. Location of the device is a key parameter affecting its air purification when there is a ventilation system, and it had great influence on CADR in UFAD and mixing system. The cleaner must be located in high concentration zones, which have high age of air.