Indoor Natural Light Performance of Clerestory Mounted Dynamic Thermally Adaptive Light Louvers

Abstract

Regulating the amount of sunlight entering a building is advantageous for various reasons. In regions with hot and sunny climates, excessive solar heat gain can increase the cooling load. Conversely, in cold climates or seasons, solar heat from south-facing windows can help heat buildings. As people become more conscious of the need for energy efficiency and environmentally friendly design, daylighting has become an important design factor. This thesis examines the effectiveness of passive daylight systems using thermally adaptive materials that interact with outdoor ambient temperatures. Existing literature has demonstrated the efficiency of both passive and active daylighting systems. However, these systems combined have yet to be sufficiently investigated for a quantitative understanding of their performance in moderating daylighting to acceptable levels inside buildings. The research focuses on developing a dynamic thermally adaptive light louver that bridges the gaps between passive and active light louver systems. In the following chapters, an analysis of a clerestory (without light louvers) and different light louver configurations (fixed flat light louver, fixed curved light louver, and dynamic thermally adaptive light louver), and their impact on daylight factors in various seasons is presented. The results showed that the fixed, curved, and dynamic thermally adaptive light louvers performed exceptionally well. During winter, the dynamic thermally adaptive light louvers curve downward to control daylight entry, resulting in the highest compliance rates with daylight factor codes. In spring, fixed flat and curved light louvers improved daylight factors, with curved louvers showing better performance. All light louvers increased daylight availability in summer, with the dynamic thermally adaptive louvers achieving the highest levels. Fall saw improvements with fixed flat and curved light louvers, while the dynamic adaptive louvers showed slightly lower performance. Overall, the fixed curved and dynamic adaptive light louvers outperformed the base case and fixed flat louvers throughout the year, with the dynamic adaptive louvers demonstrating adaptability to changing conditions. These findings highlight the effectiveness of different light louver configurations in enhancing daylight distribution and compliance with industry standards, assisting designers and professionals in selecting suitable systems.