Technology Spotlight: SSL Lighting Update

Low-powered LEDs are used for applications such as exit signs, the green power button on a computer or a red blinking light on a video camera. (Artwork by Energy Star)

High-powered LEDs, used for area lighting, combine multiple illuminator LEDs inside a fixture to produce white light. (Artwork by Energy Star)

Making light from electricity is one of the least-efficient conversions of energy we use, and it accounts for about 22 percent of U.S. electricity consumption, according to the Department of Energy (DOE). So the push is on to develop and commercialize more-efficient lighting sources.

Balancing lighting's primary purpose—enabling us to see well—with energy efficiency is not easy. Beyond just seeing, light is used to set the mood and style, create corporate identities, enhance the appearance of products, influence health, provide security and more.

Incentives, standards, codes and laws are being used to increase the energy efficiency of lighting systems. Much of that effort is devoted to light-emitting diodes (LEDs), or as DOE prefers, solid state lighting (SSL).

Overcoming market barriers

LEDs are a rapidly evolving technology, and the difference between what happens in the research lab and what is available in the marketplace can be great. Generally speaking, whatever you knew about LEDs six months ago is now obsolete, and enthusiastic marketing material may be misleading. How can you tell if this technology ready for your application now?

Both lighting and lighting controls manufacturers are constantly improving their products. LEDs show great promise for providing high-quality, energy-efficient light over a broad range of applications, but no one technology is best for all uses. Even in the applications where LEDs perform well, their current efficiency in delivered light is very close to compact fluorescent technology, and the first cost can be prohibitive. In addition to providing quality light, the system must be affordable to find a broad market.

Finding a way to provide lighting professionals and consumers with a meaningful comparison between conventional lighting and alternative technologies is another major obstacle to mainstreaming LEDs. Unlike incandescent lights and CFLs, LEDs distribute light—and heat—in a specific direction and can produce many shades of color. 

Working with researchers, manufacturers and professional organizations, the DOE Solid State Lighting group developed relevant standards that took effect in 2008. Energy Star now includes selected LED products for specific applications. The standards help customers to understand the products' performance and have realistic expectations about them.

Understanding the technology

Despite advertising claims, LED lighting at its best is not intended to fit existing fixtures. A well-designed LED luminaire is part of a package that optimizes LED light. It includes the LEDs, the driver (similar to a ballast), the fixture and reflectors or lenses to distribute the light and a heat sink. Thermal management is a big issue for high-power or high-brightness (HB) devices designed for general illumination, but much less so for low-powered novelty lighting.

With long lamp life claims of 35,000-50,000 hours or more, customers worry about how to deal with premature failures. Will matching replacements be available or will the technology be so far ahead that the whole system would need to be replaced?

The best place to begin research on LEDs is DOE’s Solid State Lighting Portfolio. It offers basic information on how the technology works, best applications, standards and testing, the CALiPER testing results and much more.

The CALiPER project is especially helpful because it tests and rates the performance of currently available LED products and shows how big the difference can be between laboratory results and real world use. It also compares products to traditional technologies.

Workshops are announced and information from previous events and other publications is available. You can register to receive free updates about the technology by email. A section is devoted to the "L Prize" which will be awarded to developers of an LED replacement for the traditional 60-watt incandescent lamp.

Energy Star products available

In the fall of 2008 the Energy Star program launched their program for white LEDs. The following product categories are now eligible for the Energy Star label. These are good applications for introducing LED technology to your facility:

• Under-cabinet kitchen lighting

• Portable task/desk lighting

• Recessed, surface and pendant-mounted down-lights

• Ceiling-mounted luminaires with diffusers

• Cove lighting

• Surface-mounted luminaires with directional head(s)

• Outdoor wall-mounted porch lights

• Outdoor step lights

• Outdoor pathway lights

• Outdoor pole/arm-mounted decorative luminaires

• Wall wash luminaires

• Bollards

SSL advocates

Other organizations and programs are working to bring LED lighting into mainstream use, too. Many are partners with the DOE program, including:

• Next Generation Lighting Industry Alliance (NGLIA) – The partnership formed SSL Quality Advocates, an initiative that developed a new, easy-to-understand and -compare, lighting performance label. 

• Illuminating Engineering Society of North America (IESNA) – The recognized technical authority on illumination.

• International Association of Lighting Designers (IALD) – Dedicated to the very highest standards in lighting design.

Other resources

• The Lighting Research Center, Rensselaer Polytechnic Institute – In addition to basic research, its ASSIST program works to bring LED technology to commercial production with appropriate testing and applications.

• LEDs Magazine – Focuses on technologies and applications of LEDs including an annual Buyers guide.

There is no simple answer to whether LED lighting makes sense for a given application and facility today. Do your homework to understand the technology better and keep up with new developments. Regard advertising with caution, be clear about what you want, ask for testing results and read warranties carefully.

Resources

Energy Star

Solid State Lighting Portfolio

L Prize

Next Generation Lighting Industry Alliance

SSL Quality Advocates

Illuminating Engineering Society of North America

Resources (cont.)

International Association of Lighting Designers

Lighting Research Center, Rensselaer Polytechnic Institute

ASSIST program

LEDs Magazine

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