Parametric study of biomimetic design of high rise office building facades in view of optimizing natural ventilation potential in the humid tropics

Abstract

In the local context, more than half of the year wind acts as a problem for high rise buildings. Ensuring natural ventilation in high rise buildings is a challenging proposition due to gradual increase in the wind speed with augmenting altitude. This reason has added to a rapid increased use in mechanically ventilated high rise office buildings, which is contributing to the energy demand. There is a prospect for using high altitude wind for naturally ventilating high rise, by way of wind calming. The objective of this research was to explore biomimetic design concept in addressing the problem indicated. This study explores potential use of the biomorphological character of a certain type of cactus from a bottom up approach where the potential of the high altitude wind in naturally ventilating spaces. The main focus was to develop a parametric fenestration concept to maximize the use of the high altitude wind for natural ventilation in interior spaces in high rise. Simulation based analysis technique was conducted for this natural ventilation study. The factors considered for the parametric study were- Length/Depth ratio; the aperture position in the cavity and the proportional width in the arms of the cavities. The base data for wind speed were used to extrapolate the maximum wind speed at different altitudes and the data were used for the boundary limit in the simulations. The interior air flow profile were evaluated against established air flow criteria of human work space. The outcomes of the simulated data were used to deduce numerical relationships between external wind speed and aperture area in terms different Length/Depth ratios of the ‘V’ shaped cavity. This study established a new type of fenestration system to naturally ventilate high rise office buildings in the context of Dhaka city. It can be expected that this study may facilitate future development of fenestration design for the high rise office buildings, to make high rise buildings naturally ventilated leading to greater energy efficiency.