Integrated daylighting strategies improve energy-efficiency. Simple and cost-effective daylight redirecting devices like light shelves have gained due importance in building design since they can give a uniform and improved illuminance. Light shelves are horizontal or inclined elements placed above a window, either internally or externally, to control and redistribute incoming daylight through reflection.

Length, height, geometry and angle of light shelf, the height of the window, slope and surface properties of the ceiling, interior surface properties, sun and sky conditions of the site are the parameters that decide daylight quantity and quality from light shelves. Researchers have established that Light shelves help in the uniform distribution of daylight deeper into the room and a reduction in lighting energy consumption by varying the above parameters. Although there exist simulation studies on the visual and thermal comfort optimization of light shelves, the heat transfer phenomenon is not well understood. The control of heat generated by the lighting system needs to be studied in detail for cooling load reduction and energy savings. The study focuses on designing and operating light shelves such that maximum daylight is uniformly distributed in the interior with minimum solar gain. The main objective of this study is to develop an empirical model to predict the heat transfer mechanism of light shelves. This involves a study on heat transmission characteristics of the light shelf and methods to control this heat. The methodology adopted is experimental research, for which a scaled prototype is tested using an artificial light source under controlled conditions.

Keywords: light shelves, daylight, heat transmission, experimental research.