A spatial prototype of natural ventilation in underground public spaces combining courtyard with wind tower

Abstract

Ventilation is the basis of controlling thermal comfort and air quality in underground spaces. Natural ventilation based on spatial designs can introduce wind, light, and scenery to improve environmental health and spatial experience, and reduce health risks and energy consumption of mechanical ventilation. This paper proposes a spatial prototype that combines courtyard with wind tower, two common spatial forms connecting aboveground and underground, and can provide effective natural ventilation to underground public spaces. Computational fluid dynamics simulations and genetic optimization were conducted in the common architectural software Rhinoceros and Grasshopper. First, spatial defects are identified and optimized by analysing the simulation results. Then, geometric variables of the spatial form that obviously affect the ventilation performance were selected and automatically optimized with the target of air volume per hour. Finally, three key issues for natural ventilation of underground public spaces are discussed including human comfort, air distribution, and ventilation reliability. This paper explores the coupling between the spatial form and ventilation performance of underground public spaces, which not only alleviates the potential conflict between energy saving and environmental health, but also provides an integrated design pattern to create more open, flexible, natural and sustainable underground spaces.