New Energy-Saving Fiber Optic Lighting System Lights Up Public Spaces
Date: Jun 06, 2013 Source: DOE Success Story (
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Challenge
Accent lighting accounts for 0.19 quadrillion Btus (quads) of energy used each year in the UnitedStates. It differs from general lighting in that the light is more directed, comes in smaller lumen packages, requires more specific color characteristics, and uses instant on/re-strike with no detectable delay between switching. The most common accent light is the 50W MR-16 halogen, which is used in the majority of accent lighting because it delivers the centerbeam candle power (CBCP) and cone angle desirable for most applications. CBCP ranges from 1200 to 20000, with a range of 40 to 8 degrees of cone angle between "flood" and "high-bay spot" accent light applications. The CBCP and cone angle are chosen in order to get a desired brightness ratio (typically 3:1 or more) between the object being illuminated and the ambient light.
As public sentiment and regulations are driving consumers toward lighting choices that save energy and reduce environmental impacts, new solutions that meet these lighting requirements are needed. However, they must also have a low first cost—the biggest challenge for energy efficient lighting systems for all applications. More energy efficient technologies existed, but did not satisfy both technical and cost requirements. The major problem for compact fluorescent (CFL) lamps is low brightness, which means that a tight beam cannot be formed. The major problem for metal halide (MH) lamps is the inability to scale to very low wattages and the prohibitive cost of buying one lamp and one ballast per light point.
Innovating Solutions
Energy Focus received DOE EERE SBIR Phase I and II funding for two separate projects to tackle these challenges. The first project was aimed at developing the crucial instant-on feature of the lights. The second sought to lower the cost of producing the lighting system so that the technology would be more competitive with standard technologies from a first-cost standpoint.
In Phase I of the first project, a series of lamp and ballast design tests were conducted to
determine the starting characteristics needed to have instant light-starting while preserving
80% of system efficiency. Lamp parameters that were tested included electrode design, fill gas type, and fill gas pressure. Ballast characteristics such as starting pulse voltage, pulse width, pulse repetition, and minimum warm-up drive current were also determined in this phase. In Phase II, final lamp parameters were determined through structured engineering tests on lamp body size, wall thickness, and inner wall shape. The gas and electrodes were optimized for manufacturability, and the ballast concept was developed into a manufacturable design.
in Phase I of the second project, the goal was to reduce the cost of a high intensity discharge distributed accent lighting systems by optimizing fabrication of the system's plastic optical fiber component, reducing the cost per point below conventional halogen sources. Eight new polymer processing approaches aimed at reducing cure time were identified and assessed, with two of the alternatives offering dramatically reduced post-extrusion processing time and lower costs. In
Phase II, the two reduced-cost polymer processing alternatives were further developed.
Energy Focus received additional support for developing these new lighting solutions from
other U.S. government agencies, including the Departments of Defense and Commerce. In 2006, the company installed its lighting systems in engineering control rooms, hangar bays, berths, welldecks, and weatherdeck locations on three U.S. Navy ships, replacing fluorescent and incandescent lighting. Nine-month sea trials were then conducted, demonstrating lower maintenance costs with no failures during the tials, increased lifetime, increased efficiency to greater than 30 lumens per Watt, and improved lighting (daylight spectrum).
