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More than a Fluorescent Copycat Rapid Advancement a Hallmark of LED Technology
June, 2009
By Ron Content
The incandescent light bulb is becoming obsolete in many parts of the world, including Canada, as regulators introduce energy efficiency standards or outright bans, and simple economics undermine the technology’s ability to compete with fluorescents and other more recent lighting innovations. CFLs (compact fluorescent lamps) and LED (light emitting diode) lighting now jockey for market share.
Upfront costs for LED lights are significantly steeper, but they can last for 30,000 to 50,000 hours. In a 12-hour, 5-day setting this could equate to more than 16 years of effective life. Switching to a technology that does not contain mercury could also save on future costs as more stringent standards for the disposal of hazardous materials are adopted.
Fluorescent and incandescent light bulbs disperse light in all directions, whereas the LED is mounted on a silicon or ceramic wafer and only emits light in one direction. This defining physical characteristic of LEDs is both a challenge and an opportunity to luminaire designers and manufacturers.
LED technology was initially seen in fluorescent equivalents, such as tube-like fixtures and recessed pot lights. In such applications the LED serves as the new filament.
However, research and development has yielded steady and fast-paced advancements – not unlike the evolution of the computer chip. ENERGY STAR currently sets a standard of 35 lumens per watt (lm/W) for lighting efficiency, but a proposal to upgrade it to 50 lm/W is expected to be adopted later this year. LED technology is similarly keeping pace.
Planar lighting is an emerging application in which LEDs do not point downward from the lamp, but face inward and shine through a high-resolution polymer plastic. With additional optical management, they emit the same amount of light as a fluorescent system but with a number of differences.
Some LED-based systems can deliver the light equivalent of a 3- or 4-lamp fluorescent system out of one 2’ x 2’ luminaire. LED lighting can help reduce glare, create softer shadows and provide the appearance of natural daylight. Emerging LED technology can even deliver two differing qualities of light – warm and daylight – via a controller that directs electricity to the luminaire as required.
LED lighting’s colour rendering performance, which is the light’s ability to display true colours as they would appear under the sun, still varies widely. ENERGY STAR sets a standard of 70 on the colour rendering index (CRI) as an acceptable level in comparison to the sun’s perfect rendering of 100. Fluorescent lighting systems typically have a CRI of 75 to 85, while some LEDs attain 90 on the CRI scale and others register in the 60s range.
The Canada Research Council is currently exploring how the quality of light affects the workplace environment. LED lighting’s adaptability for both system-wide and task oriented lighting should prove an interesting study. Ultimately, lighting technologies that reduce power consumption, improve light levels and improve the quality of light will be adopted for the long term.
Ron Content is President of GO Lighting Technologies Inc., developers, manufacturers and marketers of LED lighting. For more information, see the web site at www.goenergyeffective.com.
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