Advanced Fenestration Systems for Improved Daylight Performance

The use of daylight to replace or supplement electric lighting in commercial buildings can result in significant energy and demand savings. High performance fenestration systems are a necessary, but not sufficient, element of any successful daylighting design that reduces lighting energy use. However, these savings may be reduced if the fenestration systems impose adverse thermal loads. New fenestration technologies have been developed over the last twenty years, aiming at controlling the intensity of the incoming solar radiation, its interior distribution and its spectral composition, as well as thermal losses and gains. Some of these have proven successful for specific or general building applications, while others are still under development and testing to understand limitations and potential benefits.

In this paper we review the state of the art of several advanced fenestration systems which, are designed to maximize the energy-saving potential of daylighting while improving comfort and visual performance, at an affordable cost. We first review the key performance issues that successful fenestration systems must address, and then review several classes of fenestration systems intended to meet those performance needs. The systems are reviewed in two categories: static and dynamic. Static systems include not only glazings, such as spectrally selective and holographic glazings, but specialized designs of light-shelves and light-pipes, while dynamic systems cover automatically operated blinds and electrochromic glazings.

We include a discussion of the research directions in this area, and how these efforts might lead to static and dynamic hardware and system solutions that fulfill the multiple roles that these systems must play in terms of energy efficiency, comfort, visual performance, health, and amenity in future buildings.