Research Project Summary Information
Efficient PV- Powered LED Outdoor Light(ST8282-1)
TerraSolar USA, Inc.
Current technology provides a range of lamps for outdoor lighting solutions, incandescent, fluorescent, sodium vapor, and metal halide. All have limitations with respect to photovoltaic (PV) power: incandescent lamps are inefficient; sodium vapors have poor color rendition; and metal halides require complicated ballasts for battery operation and are difficult to start in cold weather. Fluorescent technology is an improvement over incandescent technology but light emitting diodes (LEDs) have the best efficiency in converting electrical energy input (watts) to light output (lumens) of any small lighting device. LEDs have extremely long lifetimes, 20 years or more, and LEDs are powered by low voltage DC so they can be operated on batteries with minimal electronics.
The Contractor shall (1) develop a mounting scheme that accepts diodes (plastic housing that focuses high output transparent plastic case) without attached lenses; (2) design and produce a lens and mirror system to convert the 15-degree divergence to a 60-degree cone of light; (3) develop and optimize the NiMH battery and control circuit used for charging the lighting system's batteries and controlling the illumination period and brightness of the light; and (4) develop a commercialization plan.
Benefits include energy savings associated with replacing sodium, metal halide, fluorescent and incandescent lamp sources with PV-powered LEDs for outdoor lighting.
The Contractor completed the work tasks and achieved the project goals. The prototype SPE fixture developed by RPI’s Lighting Research Center provides 1563.2 lumens, with a color correlated temperature of 2981, CRI of 64 (acceptable for outdoor lighting), and total system efficiency of 63.4 lumens/watt. The high efficiencies were achieved by optimizing LED selection (20 SPE LED modules), housing design, lens design, heat sink, and optimizing the driver input power (using only 24 watts). (The closest market competitor is the CREE WW LED with a light output of 1339.6 lumens and total system efficiency of 44.1 lumens/watt.) RPI intends to license the technology to interested manufacturers.
TerraSolar USA, Inc.
44 Court St., Tower B
Brooklyn, NY 11201
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R&D - Buildings Research