Adaptive Placement of Portable Air Cleaners under Changing Contaminant Sources

¹ Department of Construction Management, Louisiana State University, USA.
² Department of Computer Science, Louisiana State University, USA.

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Abstract. Indoor air quality is increasingly compromised by various sources of contamination, including particulate matter (PM2.5) emitted from multiple sources. In a large classroom with multiple contaminant sources, installing portable air cleaners is important to achieve the required indoor air quality by reducing contaminant concentrations at breathing level. However, contaminant sources and their locations are not fixed and may change across space and occupancy conditions. This source-location variability complicates the placement of air cleaners. Therefore, in this study, a parametric CFD investigation was conducted across three occupant distribution models (uniform, clumped, and random) and two corresponding air purifier placement configurations. Occupant locations were sampled using a Monte Carlo framework, and the resulting source configurations were modeled using Computational Fluid Dynamics (CFD) with the RNG k-e turbulence model to simulate contaminant transport. Particle trajectories for PM_2.5 were tracked with a Lagrangian Discrete Phase Model (DPM). Results across five simulated cases show that airflow-aligned placement maintained higher breathing-zone performance, while randomized source distributions and greater numbers of infected occupants degraded it. A corner placement of the portable air cleaners (PACs) resulted in a 27% reduction in mean breathing-zone particle concentration compared with central placement. The corner configuration also reduces the relative infection risk term by approximately 26%, although it operates at a lower nominal Clean Air Delivery Rate than the central configuration.