| Researchers at the Oak Ridge National Laboratory (ORNL) have demonstrated a new, more efficient method of using solar energy in commercial buildings called "hybrid solar lighting (HSL)". ORNL's HSL system collects and concentrates sunlight into multiple large-core optical fibers and routes the light to several hybrid luminaires (light fixtures) that distribute both sunlight and electric light into rooms. Using conventional dimming ballasts, the electric (typically fluorescent) lights are dimmed in accordance with the amount of distributed sunlight available. For a single story applications, a total lumen distribution efficiency of over 50% was recorded for the initial prototype having optical fibers an average of 6 m (19.5 ft) in length. The total electrical power displacement of the 1 m2 HSL proof-of-concept prototype is estimated to be between 522 - 2350 watts per 1000 W/m2 of incident solar resource depending on the type of electric lights being used in conjunction with the distributed sunlight. By adding the reductions in heat gain associated with reduced electric lamp use and predicted performance improvements achieved by a system redesign, the electrical power displaced in a commercial prototype could rise to between 702 - 3160 W (peak)/m2 of collected sunlight not including any additional electrical power that can be generated using the otherwise wasted IR energy. The color temperature and chromaticity values of the distributed sunlight emerging from the optical fibers closely matches natural sunlight and will vary slightly depending on the day, time, atmospheric conditions, and system configuration. For more information, visit www.ornl.gov/hybridlighting or call Mr. Jeff Muhs Director of Solar Energy R&D at 1(865)946-1281.
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