Full spectrum hybrid lighting for commercial buildings

G.O. Schlegel, S.A. Klein, and W.A. Beckman, Solar Energy Laboratory, USA
B.D. Wood, Department of Mechanical Engineering, University of Nevada, USA
J.D. Muhs, Oak Ridge National Laboratory, USA

Keywords

hybrid lighting, full spectrum, solar energy, commercial buildings, infrared, visible, thermal photovoltaic cell, daylighting, concentrating collector, optical fibers, luminaire, TRNSYS, SMARTS2

Abstract

Hybrid lighting is a new approach to lighting that integrates light from natural and electric sources. Hybrid lighting systems collect and distribute the visible portion of sunlight using large-core optical fibers and combine it with electrically-generated light in existing light fixtures. The natural and electric light sources work in unison to light commercial buildings where lighting represents the single largest user of electricity. The infrared (IR) portion of the solar spectrum is used to generate electricity using thermal photovoltaic cells.

Full-spectrum solar energy system targets in commercial buildings are costs under 1.00 $US/W, simple paybacks of between 2 - 5 years, and electrical energy displacement costs under 0.05$US/kWh by 2005 in most parts of the USA. Accordingly, it is expected to more than double the efficiency, affordability, and market penetration of solar energy when compared to other options such as solar electric technologies and conventional daylighting strategies.

Estimates indicate that by the year 2020 widespread use of full-spectrum solar energy systems will lead to: energy savings ranging from 10 x 109 kWh to 30 x 109 kWh; economic benefits exceeding $5 billion; and reductions in carbon emissions of greater than 5 megatons each year in the United States alone. Worldwide, these impacts will likely increase by an order of magnitude. The U.S. estimate alone equates to approximately 40% of the U.S. Department of Energy’s Lighting R&D Portfolio goal for the year 2020.