Investigation of Various Window Orientation in Daylighting Performance in Hot-Humid Climate of Subang, Malaysia

Abstract

This paper discusses the effect of window orientation on the quality of daylight in order to obtain optimum visual comfort in a lecture room in Subang-Kuala Lumpur Malaysia. Visual comfort in buildings is a vital factor to be taken into consideration and has become a priority. Research work is required in order to recognize the limitations, prospects, and challenges of orientation based on working times for daylighting strategy. The lecture room is associated with outdoor and indoor parameters including geographical location, outdoor illuminance, type of sky, orientation, room size, window to floor area, the position of window, reflectance from floor, wall and ceiling and glazing transparent. It is estimated that the window to floor area ratio in a typical lecture room is 20 percent. The investigation was carried out via Radiance in IES(Virtual Environment) for estimating the evaluated daylighting. The hourly and monthly daylight hours have simulated four cardinal orientations windows because students spend most of the daytime in the lecture room. The average amount of the outdoor illuminance in various months and selected hours of 10am, 12pm and 3pm are simulated under overcast sky and intermediate sky condition according to the Subang-Kuala Lumpur Malaysia condition. The research found that the amount of daylight reaching strongly depends on the orientation, month and time of the working hours in a lecture room. The findings in the lecture room indicate that under an intermediate sky without sun, the north-facing window can provide the best daylight throughout the year during working hours. Consequently, the paper offers to designers and building engineers as a guideline to use guidelines for determining the best orientation instead of a simulation program based on orientation, month and time.