Sunday, March 11, 2007

Active Solar for Lighting

Solar lighting Basics
Illustration of a solar hybrid lighting system: sunlight collector and tracking system, light distribution system, and hybrid luminator with controller.

Solar hybrid lighting system.

Research under way at Oak Ridge National Laboratory (ORNL) could lead to entirely new, highly energy-efficient ways of lighting buildings using the power of sunlight. This new technology, called Hybrid Solar Lighting, (HSL) would use sunlight to simultaneously light interior spaces and generate electricity.

Hybrid solar lighting makes better use of sunlight in its natural form and specifically targets the energy consumed by electric lights—the largest consumer of electricity in commercial buildings. Electric lighting accounts for more than a third of all electricity consumed for commercial use in the United States.

HSL, currently in the research and development phase, would use a specially designed collector to focus natural, full-spectrum sunlight into optical cables while simultaneously converting otherwise wasted infrared energy into electricity. The optical cables would then deliver the full-spectrum sunlight to light fixtures throughout a building. Additionally, HSL would convert sunlight to electricity much more efficiently than conventional solar technologies.

In a solar lighting and power system, the roof-mounted concentrators collect sunlight and distribute it through the optical fibers (enlargement) to hybrid lighting fixtures in the building's interior. The system also produces electricity for supplemental lighting or other uses.

Illustration of the components of a solar hybrid system installed in a commerical office.

Solar hybrid lighting system in commercial building.

There are currently two proposed applications for hybrid solar lighting systems. First, hybrid lighting systems are being developed for use in commercial buildings to displace electric lighting, which consumes a large portion of electricity in commercial buildings. The figure below illustrates one system configuration being developed for this application.

Second, researchers are investigating the use of HSL as a key component in new hybrid solar photobioreactors that sequester carbon via enhanced photosynthetic-based bio-processing at power plants, illustrated below. This concept is explained in further detail in the Hybrid Solar Lighting for Photosynthetic-based Carbon Sequestration at Power Plants poster.

U.S. Department of Energy

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