Numerical study of the effects of moving person velocity on personalized ventilation

Abstract

Personalized ventilation (PV), based on the concept of task/ambient ventilation, decouples fresh air from re-circulated air so as to improve personal exposure effectiveness (PEE) in breathing zones. Personalized air, supplied by PV air terminal devices (ATDs), penetrates the air plume around the human body in order to improve inhaled air quality in an energy efficient manner. The advantages of PV have been examined in different kinds of buildings and climates. However, very few studies have focused on the effects of moving person on PV because of the difficulties in controlling the experimental conditions. A moving person will cause the changes of pressure field and velocity field around him, which will influence the personalized air flow. Computational fluid dynamics (CFD) method is used to investigate the effects of moving person on personalized air flow and inhaled air quality of another person sitting towards the PV ATD. Unsteady state simulations and dynamic meshes are employed to simulate the movement of a walking person. Computational PEE is utilized as an evaluation index. Based on the numerical results, the impact of moving velocity on computational PEE is assessed. © 2008 ASHRAE.