Integrating aboveground and underground environments to enhance underground natural ventilation in the tropics: Case studies in Singapore

Ventilation is the primary solution for addressing elevated temperatures, humidity, and pollution with underground environments. Underground natural ventilation stands as a historical and promising strategy to reduce energy consumption and diminish reliance on mechanical ventilation. This study integrates aboveground and underground environments to enhance underground natural ventilation in the tropics. Initially, the study employed field measurements and computational fluid dynamics simulations to compare the natural wind environments and architectural designs of enclosed and detached condominiums in Singapore. The results demonstrate a strong correlation between the aboveground and underground wind environments in the enclosed condominium, revealing distinctive airflow patterns conducive to ample ventilation. Conversely, the basement of the detached condominium lacked natural ventilation and had tenuous connections to aboveground wind environments despite incorporating numerous skylights and side windows. Subsequently, the study proposes optimising architectural designs for row buildings through cross ventilation, sunshade, and greenery inspired by the architectural design of the enclosed condominium. Moreover, this study suggests some design strategies applicable to the tropics in hot and humid climates. These findings help architects and engineers create sustainable, natural, airy underground spaces.