Impacts of orientation on daylighting in high-rise office buildings in Malaysia

Orientation is one of the important factors in building design to use daylight and ‎conserve energy. Well-orientated buildings maximise daylight reception through ‎building facades and reduce the need for artificial lighting. Reasonable daylighting usage in office buildings is an important part of an architect’s designing process, which leads to lesser electricity consumption as well as providing a visual and thermal comfort for the occupants. Orientation is an important factor in passive design strategies. This paper focuses on the orientation effect on daylighting into office rooms. The research method of this study was simulation which is performed on a hypothetical model on a 25 storey high-rise office building in Malaysia. All simulations were carried out in the IES-VE software that uses RADIANCE program for illuminance calculations. To evaluate the daylight in various conditions, a new index SAZ was introduced which assesses daylight factor (DF) and absolute Lux. Results showed similar SAZ in CIE overcast sky in various orientations; whereas, in sunny sky due to sun path in Malaysia, different results showed northern and southern rooms have the best illuminance distribution. However, the similar window form and size in four orientations lead to more energy consumption for artificial lighting and cooling loads.