Minimizing solar insolation in high-rise buildings through self-shaded form

Abstract

High-rise buildings experiences overheating conditions especially in hot humid tropics. For a high-rise built form, vertical surfaces receive the most critical impact from solar radiation. This study examines the effect of geometric high-rise forms against the amount of solar insolation received by the external surfaces, and the generation of self-shading strategies where high-rise buildings form are selfshaded from solar insolation during the required period. The study is divided into two main parts and conducted using building simulation program ‘ECOTECT V5.2b’. The first part is on the evaluation of the effect of geometric shapes based on annual total solar insolation received on the entire exposed vertical surfaces. Circular and square generic shapes with their variations in width-to-length ratio and building orientations are generated. Circular and square shapes with width-to-length ratio 1:1 received the lowest annual total solar insolation. They are selected as the optimum shapes. The second part is the modification of stepped inverted geometry method involving four different depths of self-shading projections to building height. Each floor are experimented based on direct and diffuse components of solar insolation received on vertical surfaces for three different design-days. The simulation results revealed that significant reduction of 60% direct solar insolation could be achieved by self-shading projection ratio of 1.00, 0.75 and 0.25 on east, west, north and south wall respectively. Circular shape with varying wall orientations and curvatures performed better compared to square shape. With appropriate attentions given to the proportion of geometric shapes and self-shading projection ratio, the impact of solar radiation on high-rise building shape can be minimised. Hence, it can be assumed that the energy consumption used for cooling load can also be reduced.