NATURAL VENTILATION STUDIES OF EXTERNAL AND INTERNAL ENVIRONMENT OF HDB FLATS

Abstract

This paper is a study of natural ventilation of high rise public residential housing in Singapore through the use of nonstandard computational fluid dynamics (CFD) simulations. A new innovative methodology will be used to simulate the external and internal environment at the same time, made possible by recent developments in CFD technology. With that, the study attempts to explore the relationship between outdoor and indoor wind velocities, termed as the wind velocity ratio in the paper, as well as analyse factors that affect indoor natural ventilation. A 3D model of a generic typology is derived based on to-date HDB layouts and configurations, which includes the surrounding environment as well as typical interior of the apartment block. Apartment units based on a generic 4-room flat are tested at different floor heights and different orientation based on two prevailing winds. Different points within a unit are also tested in both cases where the main entrance door is opened and closed. Results based on the different variables are tabulated and analysed. Comparisons between simulations reveal that wind velocity at apartment facade does not directly correspond to apartment height as wind flow pattern is affected by massing of the apartment block. It was found that indoor wind velocity is affected by the availability of space between openings in units and nearby external obstructions. The positions within units also differ in amount of wind received because of the varying wind path through the interior. The results also validated the positive co-relationship between interior openings and wind velocity ratio. Due to several limitations, the paper serves as a basis and framework for future studies, and provides recommendations of how it can be further developed to constitute a design guideline for future public residential housing.