An enhancement of the daylighting from side-window using two-section venetian blind

In the tropics, daylighting from a side window requires shading to intercept direct sunlight from entering the window whilst allowing penetration of daylight from sky. Daylighting from a double-pane glazed window with enclosed horizontal slats has long been investigated under different climates and locations. In this paper, a double-pane window with the slats that were separated into two sections (lower and upper sections) was investigated for its daylight application in tropical climate. A series of full-scale experiments and simulations were conducted under real tropical skies and by which the slats in each section were tilted to different angles. Through the yearly simulations, performance of the two-section slat window was evaluated in terms of "useful daylight illuminance" (UDI), average interior daylight illuminance (ADI), and reduced light power density (LPD) of a dimmable lighting system. The results show that the two-section slat window can enhance the daylight use in the building by increasing more useful daylight illuminance, and providing better uniformity of the interior daylight distribution than the single-section slat window.