Solar power: future bright for new system
Copyright 1999, Environmental News Network
December 30, 1999
By Environmental News Network staff
An energy system that uses the visible portion of the solar spectrum to light buildings and the non-visible portion to generate electricity has the potential to make solar power a dominant player in the energy marketplace.
"By possibly tripling the electrical power displacement efficiency and lowering the cost of solar energy by more than a factor of two, full-spectrum solar energy systems are poised to revolutionize the solar industry," said Jeff Muhs, a researcher at Oak Ridge National Laboratory in Tennessee.
A roof-mounted tracking system separates the visible and non-visible portions of the sun's rays and pipes the visible portion of the spectrum, via cylindrical, large-core optical fibers, to light fixtures inside buildings. The non-visible portion is used to generate electricity.
The light fixtures, called hybrid luminaries, use both natural light and electrically generated light to maintain consistent lighting inside a building. Thus, when it is dark outside, lights remain on inside.
"Since lighting is the single largest electrical power use in commercial buildings, it makes sense to use sunlight directly for lighting rather than converting it into electricity only to reconvert close to 30 percent back to light," said Muhs.
The new technology also concentrates photovoltaic cells in the near-infrared portion of the spectrum, where they are most efficient at converting sunlight into energy.
This full-spectrum system is a part of new approach to solar power aimed at eliminating fossil fuels as an energy source for commercial buildings.
"Zero-energy-buildings will optimally combine solar energy technologies with energy-efficient construction techniques to create cost-effective buildings that have a zero net need for fossil fuel energy on an annual basis," said Muhs.
The technology has already excited Oak Ridge partners such as Translight LLC of Pomfret, Connecticut, a manufacturer of large-core optical fibers.
"Our analysis indicates that there is a realistic opportunity to achieve simple paybacks in less than five years using this hybrid approach to solar energy," said Translight director Hanafi Fraval.