Daylight Performance in a Low-energy Atrium Building in Hot Humid Climate

Atria are now one of the most important strategies for the design of energy-efficient buildings. Using atria have become very popular in modern buildings, particularly large commercial buildings, such as hotels, shopping malls and office headquarters. Most of the existing atrium buildings in the world are top-lit with fully transparent glazed roof system. This type of atrium is not energy efficient for hot humid regions; because the main design problems that affect the thermal and energy performance in atria which located in hot humid regions are over lighting and overheating due to roof glazing system which are typically horizontal top-lit. Based on previous research, the use of clerestory windows instead of skylight is a good strategy for controlling direct sunlight and improving the human comfort conditions in hot humid atria. This paper aims to examine the impact of this type of fenestration of window (clerestory) on the amount of daylight obtained in the atrium and its adjacent rooms. A 4-story conceptual low energy atrium form is developed based on the vernacular design features of hot humid regions, to be used for computer modelling studies under overcast sky conditions. Several atrium cases, characterized by different ranges of width and different heights of clerestory, are analysed to predict Average Daylight Factor (ADF), in the spaces, developed through computer simulation using Radiance in IES. The result of this research shows that, there is a direct relationship between variations rate of ADF and variations rate of clerestory height (h); in atria with the same width, the variations rate of the Average Daylight Factor at the atrium floor and office rooms are approximately equal to the variations rate of clerestory height.

Keywords:

daylight , atrium buildings , clerestory window , hot humid region