TA-23-C057 – The Impact of Thermally Adaptive Light Louvers Attached to Clerestories on Indoor Natural-Light Performance During the Winter Season PDF

Daylighting can decrease annual building energy consumption by minimizing electrical lighting. However, daylight and sunlight can cause unwanted heat gain and glare. Therefore, shading devices and light redirecting devices such as light louvers are usually attached to windows to control heat gain and glare. Fixed angle light louvers aren’t optimized for the changing sun angles throughout the year but are easier to maintain due to the absence of moving parts. Dynamic, adjustable light louvers on the other hand are better at addressing a range of sun angles but are more costly to maintain due to moving mechanical parts. This research project examined the performance of a dynamic, adjustable light louver using thermally adaptive material which allows the light louver to adjust to seasonal differences based on temperature but without any moving mechanical components. Utilizing an experimental set up in Lawrence, Kansas, this project compared the daylight distribution performances between a fixed horizontal light louver, fixed curved light louver, and a thermally adaptive light louver attached to a south facing clerestory window over the course of a year. The initial winter season findings showed the thermally adaptive louvers performed the best in meeting a daylight factor of 2% to 5%. The thermally adaptive louvers met this range by 23.1% of the time compared to just 18.5% for the fixed horizontal louvers and 18.1% for the fixed curved louvers at horizontal tabletop level.