CFD simulation study of the performance of personalized ventilation system with coaxial air supply device

School of Mechanical Engineering, Tongji University, Shanghai, China

^* Corresponding author: gaonaiping@tongji.edu.cn

Abstract

Personalized ventilation (PV) has significant potential in improving inhaled air quality, accommodating individual thermal preferences, and reducing energy consumption. However, the performance of PV system is greatly dependent on the structure of the supply air terminal device (ATD) and the resulting airflow patterns. In this study, we introduce a novel PV system equipped with a coaxial double air outlet, designed to achieve a specific velocity profile by modulating the flow rates from both internal and external outlets. The performance of this PV system is investigated using CFD (Computational Fluid Dynamics) simulations in a typical office room with mixing ventilation (MV). To accurately reflect the airflow distributions around occupants, a life-size computational thermal manikin (CTM) is employed. This paper studies the influence of different flow ratios (e.g., 0-1) of the ATD on the inhaled air quality and local thermal comfort of occupant. The results demonstrate that optimizing the velocity profile to a “top-hat” distribution can improve ventilation effectiveness by about 10% compared to a uniform velocity distribution. This study provides valuable references for designing PV systems in different application scenarios.