To some project teams, “daylighting” means using glass area to admit direct sunlight, period. Yet there are better approaches to illuminating building interiors. Often, the sun’s direct rays are the last thing you need for effective daylighting. Sunlight comes with high solar heat gain—measured as solar heat gain coefficient (SHGC) for various types of glazing and translucent materials—and can lead to glare, occupant thermal discomfort, and material degradation caused by ultraviolet (UV) light.
Building occupants and owners want useful, uniform light, not high-contrast or high-heat sources, according to surveys like the seminal study led by the University of Washington (https://tinyurl.com/zhpx7h3). That’s why controlled and redirected sunlight almost always provides the best approach, while direct rays may be counted among the least desirable techniques. Building surfaces and enclosures receiving direct sunlight need solar control systems, including shading devices such as overhangs and fins that may be opaque or translucent, solid or louvered, according to the Best Practices Manual published by the Collaborative for High Performance Schools. Canopies, window films, and insulated glazing units (IGUs) with internal louvers may also be required. Façades and areas facing north, on the other hand, need ways to maximize daylight harvest.
After reading this article, you should be able to:
+ DISCUSS the benefits and ideal kinds of daylighting illumination desired for such interiors as workplaces, libraries, and museums.
+ DESCRIBE the types of enclosure technologies and wholebuilding design approaches for maximizing beneficial daylighting.
+ LIST techniques for improving daylighting performance.
+ COMPARE the methods or materials commonly used in daylighting applications.