Integrated design for underground space environment control of subway stations with atriums using piston ventilation

Abstract

In subway stations, the piston effect plays an important role in enhancing ventilation to improve subway environment and reduce energy consumption. However, it may induce negative impacts on environmental health and thermal comfort, i.e. air pollution and strong wind. Traditionally, the architecture and ventilation systems are designed separately, and normal ventilation design follows architectural layout. Actually, the architecture design can have a significant influence on the ventilation performance, e.g. airflow pattern. Therefore, this study aims to integrate the design pattern of the architecture with an appropriate ventilation system. A typical subway station of Nanjing (in China) was considered. A dynamic-mesh based computational fluid dynamics (CFD) method was adopted to simulate ventilation performance in the presence of piston effect. Field measurements were conducted to validate the numerical method. New measures were proposed from the perspectives of architectural design to improve the ventilation effect, including enlarging atrium space, adding atrium vents and funnel-shaped exits, etc. The numerical results show that the optimal architectural design could provide a significant improvement towards the airflow environment and ventilation efficiency while avoiding serious air pollution. The proposed integrated-design pattern could further facilitate the creation of an ‘energy-saving’ and ‘healthy’ underground space environment.