The Future Looks Bright: Energy-Efficient Lighting Technologies

New advances in controls, fixtures, lamps and more help reduce energy costs and environmental impact.
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Sponsored by Engineered Lighting Products, Journée Lighting, Kim Lighting, and WattStopper
C.C. Sullivan

Confirming SSL Benefits

As for the industry standard, Mor explains that the Illuminating Engineering Society's LM-80 testing procedure is the main evaluation of chip performance. However, it falls short of informing the specifier how that chip will perform once it's paired with a driver and installed in a luminaire. For that reason, Mor recommends reviewing the Energy Star label, which not only analyzes LM-80 data but also compares it against heat-testing of luminaires. In addition, savvy end-users should clarify the warranty details of what is considered a failure prior to purchase.

Circling back to another SSL benefit, reduced maintenance, manufacturers like to emphasize the technology's long life, often 10 years. As such, disposable luminaires have made their way into the marketplace. Because these units are unserviceable and meant for one-time, extended use, it becomes even more critical to have proper thermal management, protection from dust and dirt intrusion and shielding from incoming power spikes.

While this "no-maintenance" product does seem attractive - and could be a good choice for easily accessible outdoor applications such as landscape or roadway lighting - the industry's overall reaction has been mixed.

First of all, if the fixtures fail prematurely, replacement may require destructive measures such as cutting into a drywall ceiling, says Willmorth, which would be unacceptable. Replacement could also impact design integrity for the lighting systems. He adds, "If the products are replaced at end of life with no control over optical performance, how can a designer be sure that the space will remain as designed down the road? In some spaces, 50,000 hours is only seven years."

Most of all, throwing away the product - aluminum, glass, plastic and all - is far from sustainable. "What we need is better innovation of replaceable parts or better recycling by the luminaire manufacturers," says Mor.

Fortunately, some manufacturers have developed LED modules and chips that are easy to replace. "Today, there are fieldreplaceable modules that are end-user and consumer-friendly," contends Journée Lighting's Alexander. "Some modules have all the electronics inside the module including the LED driver circuit, meaning that the fixture itself does not have any components onboard which can fail over time." One module, he adds, has a thumb switch to change the fixture wattage, from six to eight to 10 watts.

Moving on to another key technical issue, color rendering index or CRI - and, in some cases, its R9 value, a measure of rendering deep red colors - requires attention. While a CRI of greater than 80 is usually acceptable in general settings, for retail and critical color applications, at least 85 and perhaps as high as 92 is required. Meanwhile, levels for R9 - oftentimes weaker with LEDs - should be at least 90 for critical color settings, advises Willmorth.

When investigating color rendering, Mor cautions that manufacturers may misrepresent this data, so it's important to review the company's "color constancy" policy. "I want to make sure that luminaire is going to have constant color when I order it today, and in three years," he says.

Controls: Reducing Energy Use

Another very significant approach to reducing lighting energy use is by integrating lighting controls in new and existing projects. Whether it's a straightforward bi-level switching set-up or the use of occupancy sensors or multiple illumination levels - or a more advanced daylighting harvesting or building-automation system (BAS)-integrated scheme - energy savings are there for the taking.

"A researcher at the CLTC, the California Lighting Technology Center, captured the opportunity in 2008, saying, "If commercial buildings used existing lighting control technologies, they could see an immediate and sustainable savings of 50 to 60 percent,'" recalls WattStopper's Horton.

The simplest approach is priming occupants to use controls properly, says the lighting designer Gordon. "The most effective control in America today is a toggle switch," he says. "If you just turn off the light when you're not using it, we would save enormous amounts of energy." The next step up is bi-level lighting, Horton explains, a requirement for California Title 24, EPACT 2005, and now part of ASHRAE 90.1-2010. "This allows spaces to operate at a medium lighting level most of the day while occupants are on the phones or working with their computers," he says. "When an occupant needs a higher level of lighting, which occurs about 20 percent of the time, the occupant can raise the light levels to meet the task requirements."

Another low-tech, low-hanging opportunity is found in controlling plug loads, which includes not only task lighting but also computer monitors, coffee makers, printers and other nonessential plug-in devices. "If we could leverage the control system that turns off the lights to also control these nonessential loads, we'd get significant energy savings with very little incremental capital investment," says Horton.

 

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Originally published in GreenSource
Originally published in September 2010

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