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

New LED fixtures with replaceable modules and large heat sinks areas, which extend the life of the light source, are being used in a variety of applications to save energy.

Photo: Journée Lighting

Codes for Smarter Buildings

Beyond today's flexible, easy-to-use control systems, energy codes are driving the adoption of intelligent lighting, says Pete J. Horton, vice president of market development with WattStopper. "Bi-level lighting, a requirement for California Title 24, EPACT 2005, and now part of ASHRAE 90.1-2010, provides for off, medium and high levels of lighting," he explains. In addition, ASHRAE 90.1-2010 will require automatic plug-load controls for 50 percent of receptacles, including those on modular partitions.

"State energy codes require efficient lighting sources measured in watts per square foot, automatic shutoff, usually an occupancy sensor or timer, manual on-off control, and multilevel lighting control," Horton adds. These measures also cut lighting costs from $0.40 to $0.60 per square foot to $0.15 to $0.25, depending on hours of use, occupancy and utility rates. A few municipalities even mandate daylighting: Seattle, for example, has stringent standards for natural light indoors under its 2009 Energy Code that require individual controls or daylight- or occupant-sensing automatic controls.

Other codes and standards driving the industry toward energy-efficient lighting and daylighting include the new LEED Version 3, which outlines a provision for lighting controls that enable occupant adjustments to meet both individual and group preferences. Title 24, California's energy code, now requires "Smart Grid" demand-response controls in retail stores of 50,000 square feet or more.

It's more than codes, of course, pushing project teams to focus on illumination. The main impetus? "Operating cost," says Scott Schuetter, energy engineer with the Energy Center of Wisconsin, Madison, WI. "Lighting comprises around 20 percent of a commercial building's energy use, and replacement is a costeffective means of reducing energy usage, with paybacks of typically around a year."

Application is Everything

Lighting control system at the Department of Energy's Research Support Facility at the National Renewable Energy Laboratory

Photo: RNL Design/Frank Ooms

The big question is how to maximize resources, minimize upfront costs and optimize energy use. Because many aspects of design and application bear directly on system efficiency, careful attention to as many factors as possible will help assure success.

While general design rules - maximizing natural light, for example - can seem appealing, the most fundamental determinant of efficient lighting design strategy is project type. The chart at right shows the range of required lumen levels for specific areas in commercial property types, devised by Rensselaer Polytechnic Institute's Lighting Research Center as guidelines for architectural applications of LED devices. The lower end of each range, indicated by a bar, represents the ideal, where lighting operates at 100 percent efficiency; the high end of the range represents 50 percent efficiency.

"The first step, without doubt, is to understand the needs of the client and the building. Inefficiencies in lighting energy use are related to systems that don't match how the building will be used," says Andrew Corney, sustainable design director with WSP Flack+Kurtz division Built Ecology, San Francisco, CA. "The second task is to understand the client's expectations: How do they expect to use and control their environment, and who is going to be making decisions about the quality of the light environment and its suitability?" The third task, Corney adds, is to select the products and approach that best meet the project needs.

 

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Originally published in GreenSource
Originally published in September 2010

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