The genius of solar lighting is self-evident—you've got your zillion-lumens light source right there in the sky. It's the medium that presents the challenge: how to direct and spread the light effectively? We've seen some great low-tech solar lamps manufactured for the developing world. The popular solar-LED-powered D.Lite, for instance, holds a charge from the sun or an electrical outlet. And the clever Liter of Light uses a water bottle ensconced in a roof tile to create an insta-skylamp.
To light an interior completely, though, requires more than a vending machine's worth of Dasani strung together on the ceiling. We need serious optics for that! Enter the London-based venture Sunportal, which says it's found an efficient way to pipe sunlight through a space, allowing you to light a building both efficiently and effectively.
Sunportal's Active Sunlight Collector (basically a giant reflector) tracks the path of the sun and bounces light upward into a concentrator, which focuses the reflected light into a small aperture. This concentrated sunlight then passes through a series of pipes that distribute the light evenly through the building. The company uses relay lenses in the pipes to maintain the light's intensity. They also coat the tubes with an "infrared-cut coating," which is supposed to prevent heat loss and gain during transmission. Because the Active Sunlight Collector also tracks the sun when it's cloudy, Sunportal claims that their system works even on overcast days.
Sunlight bender and relay lenses, part of a system installed in a South Korea power plant.
According to their website, the company currently has a few dozen dealers in Europe and North America, plus a few installations in South Korea, in a steel mill, a subway, and a power plant.
In combination with regular old PV, Sunportal's system could be one more smart strategy for net-zero buildings (assuming the cost isn't prohibitive). Traditional sunshades and solar orientation will obviously never go out, but how cool would it be to flip a switch that turns on the sun?
All images courtesy of Sunportal
The sunlight concentrator.
The solar pipe with relay lenses.