Observation s on Performance of Commonly Used Shading Devices in Tall Office Buildings of Dhaka

Abstract

Solar radiation is a major source of heat gain for building in the tropics. Large vertical surfaces of tall buildings are exposed to solar radiation and needs to be controlled in view of generating desirable indoor environment. Solar shading is one among the many strategies in dealing with overheating problem in a tropical city like Dhaka. External shading device is the most efficient solar control as it cuts off solar radiation before reaching the window. This paper presents a simulation study of evaluating performance of shading devices on windows in the context of Dhaka (Latitude 23.5°N). Six selected shading devices were evaluated based on percentage of shaded area on windowpane and energy saving potential of shading devices. Simulation results showed that the design of the shading devices need to be explored for desired performance. The results also indicated that depth and spacing of overhangs as well as depth, spacing and angle of vertical fins have significant effect on shading performance. Modification of these parameters may make the shading devices effective in different orientations at the desired periods.