How electrical professionals can analyze emerging LED technologies
The early years of any technology are invariably the most exciting, as we welcome a whole new way of doing things that is simpler, faster, or more efficient. But with that excitement typically comes some degree of confusion, as we grope our way (without standards or a yardstick) toward familiarity with a technology we don't yet fully understand — all with the market moving at warp speed to keep pace with the latest developments.
That's essentially what's happening today with solid-state lighting (SSL), lighting applications that include light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or light-emitting polymers. As news spreads of SSL's unique advantages — which, in addition to energy efficiency, include directionality, controllability, vibration resistance, long life, and aesthetic appeal — the number of LED products flooding the market is increasing at a dizzying pace. Although some of these products are quite good, many are not. This creates an environment where it's difficult for anyone to tell the wheat from the chaff — and too much chaff can make consumers wary of the technology altogether. For more information on how to analyze emerging LED technologies, see Checklist for Today's SSL Market on page 11.
Compounding the problem, many SSL manufacturers have a tendency to get carried away when it comes to writing their product literature. This has been revealed repeatedly in DOE's CALiPER program, which supports the continuous, unbiased testing of a wide array of LED products available for general illumination. Since it began in October 2006, CALiPER testing has found inaccurate or misleading literature for many LED products — more than half of all those tested in CALiPER Round 9, which was completed in October 2009. Although there's been improvement since the early CALiPER rounds, this percentage is still too high.
Getting on the same page
To address the problem of exaggerated product claims, DOE launched an initiative in December 2008 called SSL Quality Advocates, which was developed jointly with the Next Generation Lighting Industry Alliance. SSL Quality Advocates is a voluntary pledge program to ensure the accurate representation of LED lighting in the marketplace — not only in product labeling, packaging, and literature, but also on press releases and manufacturers' data sheets. The ultimate goal of SSL Quality Advocates is to facilitate consumer adoption of SSL and, in so doing, avoid the kinds of missteps that prevented compact fluorescent lamps (CFLs) from catching on in the 1990s.
The SSL Quality Advocates program is open to all who manufacture, sell, or recommend LED lighting. At the heart of the initiative is a new, standardized Lighting Facts label, similar to the U.S. Food and Drug Administration's Nutrition Facts label, that can be affixed on LED products, packaging, or literature. This Lighting Facts label (Graphic above) provides a simple, consumer-friendly summary of verifiable product performance data, as measured by the new industry standard for testing photometric performance, IES LM-79-2008.
Manufacturers who take the Lighting Facts pledge agree to follow the guidelines and use the Lighting Facts label, which reports SSL product performance results in five areas: lumens, efficacy, watts, correlated color temperature, and color rendering index. Other partners (buyers, contractors, lighting designers, distributors, retailers, utilities, and efficiency organizations) agree to look for and use products that bear this label. Promoting accurate reporting of LED product performance in this way is crucial to consumer acceptance. Negative experiences can adversely affect consumer attitudes for many years, as we learned from the market introduction of CFLs. To find out more about the SSL Quality Advocates initiative, visit www.ssl.energy.gov/advocates.html.
Putting LEDs to the test
Ongoing CALiPER test results provide a report card on the current status of SSL technology, indicating areas of strength as well as weakness, with each CALiPER summary report conveying the findings of a particular round of testing. What has CALiPER shown so far? On the positive side, there are more LED products that approach, match, and sometimes even exceed the light output levels, distribution, and color quality of similar lamps and luminaires that use traditional sources, such as incandescent, halogen, and CFL.
The previously mentioned profusion of inaccurate or misleading product claims proves to be much more negative. Especially troubling is the fact that equivalency claims for LED replacement lamps (e.g., “compare to standard 60W bulb,” “directly replaces 35W halogen”) are almost always false and misleading.
Even though it's generally agreed that LED replacement lamps don't take full advantage of SSL technology, which works best with fixtures designed specifically for LEDs, the fact remains that there are millions of conventional luminaires already in use — luminaires that will be in use for many years to come. This means LED replacement lamps will be a sizable market in the near future.
Overall, a wide range of performance has been found among LED replacement lamps. Some products clearly represent viable replacements for incandescent, halogen, or CFL lamps; others fall short of manufacturer claims. In general, they perform quite well with respect to efficacy, color quality, and intensity, but not necessarily so well when it comes to total light output, power factors, and accuracy of product ratings. To stay on top of the latest CALiPER test results and market trends, visit www.ssl.energy.gov/caliper.html.
The Gateway to SSL success
Another effective way to advance our understanding of the emerging SSL market is to systematically test LED products in real-life situations and make the results available to the public. That's exactly what DOE's Gateway demonstrations do. They showcase high-performance LED products for general illumination in a variety of commercial and residential applications — from highway bridges and supermarket parking lots to city streetlights, parking garages, and residential homes.
Gateway results provide real-life experience and data on state-of-the-art product performance and cost effectiveness. For each completed Gateway project, DOE publishes a summary brief as well as a detailed report that includes analysis of data collected, projected energy savings, payback analysis, and user feedback. To download Gateway reports and briefs — or to learn more about the Gateway program — visit www.ssl.energy.gov/gatewaydemos.html.
Although the learning curve for SSL is a steep one, its ascent is well underway — and the climb is being facilitated by an ever-growing body of reliable information. Gateway demonstrations, CALiPER testing results, Lighting Facts label data, and lists of design competition winners (Photo 1 on page 10 and Photo 2) enable buyers to make more well-informed choices. They also help ensure that as LED lighting products pour into the marketplace at this crucial early stage, the first impressions they make will be positive ones.
Brodrick, Ph.D., is the solid-state lighting portfolio manager for the U.S. Department of Energy, Washington, D.C. He can be reached at firstname.lastname@example.org.
Sidebar: Checklist for Today's SSL Market
Making use of the growing arsenal of information, analysis, and reports available in the industry, it can still be a challenge to stay current with a market that's as fast-moving as solid-state lighting (SSL) is today. The following checklist provides a quick and handy resource for analyzing emerging LED technologies.
What are the delivered lumens?
What is the real input power?
Do you have LM-79 photometric reports and IES files from an independent testing lab?
What is the color rendering index (CRI) at each color temperature?
How do you ensure color consistency among fixtures built today or a year from now? Over the life of a product?
Does the thermal management system keep the LED junction temperature below specified maximums in all applications?
May I see at least two samples of the same correlated color temperature (CCT)?
Were your chromaticity measurements performed according to LM-79 by an independent lab?
Is there a written binning policy?
Is there a written end-of-life policy? How will spares be made available?
Do all system components from SSL manufacturers have a warranty and labor to fix/replace?
How long is the warranty? What exactly is covered?
Has LM-80 testing been performed by your LED or LED module manufacturer? What does it say about lumen maintenance?
Whose LEDs are being used?