In the design of an atrium, good qualities of daylighting and thermal performance are expected. This thesis deals with a parametric study of geometric effect on the daylighting and thermal performance of three typical types of atriums, enclosed, linear and semi-enclosed, in the subtropical climatic area.

Atria have proliferated in a range of contemporary buildings and daylighting is perhaps their most valuable aspect. This thesis is an exploration of the effects of atrium facades on the daylight performance of an atrium and its adjoining spaces. It examines the effects of atrium wall surface reflectance distribution patterns, different surface types, and the location, size and proportion of fenestration and opaque areas in an atrium’s facade. The study seeks to provide knowledge that would be most useful at the early design stages of a project. The study uses Daylight Factor (DF) and Average Daylight Factor (ADF) to examine daylight levels in an atrium building. Chapters Two and Three develop an understanding of key daylighting concepts and consider specific daylight linked atrium parameters related to this study; atrium geometry and enclosing surfaces each of which is examined through an extensive literature review. Chapter Four demonstrates the effects of reflectance distributions and diffuse and specular surfaces on DFs across the atrium floor using physical scale models. Following this, in Chapter Five, the experiments are repeated using RADIANCE and results from the two methods are compared to establish their accuracies. ADF values, calculated using Littlefair’s (2002) algorithm, are also compared with those obtained from physical scale model and RADIANCE. Chapter Six establishes the range of atrium well indices in which surface reflectance distributions affect DFs. This then informs the experiments of Chapter Seven which ascertain the influence of different facade compositions (with variable and even fenestration from the atrium roof to its floor) on daylight availability in atrium buildings. To contextualise work undertaken in this thesis, the research findings are compared with data from real buildings. Finally, specific conclusions with regards to the effects of atrium facades on daylighting in atrium buildings are drawn before more wide-reaching inferences are made.