Optimizing Air-Supply Parameters to Minimize Contaminant Concentrations in the Breathing Zone Using Proper Orthogonal Decomposition

Document Type

Conference Proceeding

Publication Date

1-1-2026

Abstract

Supply air parameters, such as flow rate, flow direction, and diffuser type, govern the diffusion of indoor particulate matter and influence the transmission of droplets. Particles of different size ranges respond differently to the ventilation parameters. In this study, rooms with various particulate sources and ventilation parameters were modeled with transient CFD simulation to understand the behavior of droplet nuclei across multiple ventilation scenarios. The design of air supply parameters with trial and error and experimental methods is inefficient and time-consuming for modeling particulate matter, and they cannot be used to identify the optimal air supply parameters. Therefore, in this paper, proper orthogonal decomposition (POD) is applied to study ventilation parameters in a mixing ventilation system, aiming to reduce particulate contamination in the breathing zone of occupants. This study employed POD in steady-state mode. The experiment was conducted in an office with five adjustable supply inlets and two ceiling-mounted exhaust vents. Measured airflow and concentration fields were then compared with those from computational fluid dynamics (CFD) simulations, providing validation of the numerical model. Droplet nuclei concentration in the human breathing zone was selected as a design objective to optimize air supply parameters. Design parameters (such as mass flow rate) were considered, and the design parameters' sensitivity was analyzed by orthogonal cases to understand the optimized scenario. By considering the angle of dispersion of exhaled droplet nuclei in the room, the appropriate ventilation parameters can reduce the concentration of droplet nuclei, thereby enhancing traditional ventilation parameters for more advanced control of HVAC systems.

Publication Source (Journal or Book title)

ASHRAE Transactions

First Page

867

Last Page

875

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