Even with the most advanced lighting products, there's a tradeoff. You can have bright lights, you can have energy-efficient lights, you can have "full-spectrum" light, but short of bringing actual sunlight inside, you probably aren't going to get all three. Skylights and solar tubes can direct sunlight down inside from the roof of the building, but their effectiveness diminishes as the sun moves across the sky, especially in the winter, when the sun is at a lower angle.
However, by using a system of moveable mirrors, which are directed by a solar-powered GPS device, inside a skylight, natural daylight can be brought into a building virtually all day long, giving workers or residents the benefit of not just free lighting, but the natural richness of the sun's rays.
The difference between the passive daylighting systems (such as a conventional skylight or windows), and active daylighting systems, such as the SunTracker from Ciralight, is that instead of having some points throughout the day when the daylight is low, or other points when the light is glaring, they provide not only even lighting throughout the day, but they do so at a bright enough level that electric lighting can be turned off in many cases.
At the heart of the SunTracker system, a series of three mirrors, mounted to a moving frame under a polycarbonate dome, direct sunlight down through a diffusion lens (which distributes the sunlight instead of focusing it on a single point) into the building. An attached solar-powered GPS controller determines the exact location of the unit in relation to the sun, and keeps the mirror array angled to the sun throughout the day (also using solar energy), allowing it to direct the maximum amount of daylight from just after sunrise to just before sunset.
According to Ciralight, SunTrackers will deliver up to 300% more sunlight than passive skylights, which could make the difference between having to use electric lighting or not during the day.
Daylighting isn't simply for reducing the dependence on electrical lighting, as natural lighting has been shown to be related to enhancing human health, as well as increasing productivity and boosting morale. In retail settings, daylighting has been linked to increased sales, and to increased test scores and grades for students in schools with daylighting.
Currently, the SunTracker is available in a 4'x4' or 4'x8' size, with several different choices of diffusion lens, and are offered with optional security bars or a roller shade system (to reduce the amount of light entering the room on demand).
Find out more about this active daylighting system from Ciralight.