LEDs took center stage at this year’s festival of lights
More than 14,000 architects, engineers, designers, and end-users from around the world converged at LightFair 2005, on April 12 to 14 at the Jacob Javitz Convention Center, New York City. They came to review a variety of new products like ballasts for dimming various arc discharge lamps, and to learn about the latest in energy-efficient sources and sophisticated network control technologies.
Following last year's show trend, a large number of solid-state light sources, which include the LED (made from silicon) and the organic LED source (made from polymer), received a great deal of attention. About 80 companies exhibited LED products at this year's show, and four out of the six top new product awards, including Best of Show, went to these solid-state lights. The new product showcase featured 34 LED items, and about 30% of the exhibitors presented at least some LEDs, compared to roughly 10% last year.
The basics of LEDs are widely known. However, when it comes to the more complicated concepts related to the technology, awareness is significantly lower. Without any published standards to guide them through LED installation, lighting designers must rely on manufacturers and reps for this kind of information. Yet because wide scale application of the technology is still in its infancy, few LED-savvy industry members exist to offer designers that kind of guidance, making shows one of the few alternatives.
The advantages of LEDs were discussed everywhere at the show: somewhat efficient generation of colored (and white) light, small form factor, imperviousness to environmental condition, long life, and — most importantly — greater efficiencies in the future.
Almost on a monthly basis, manufacturers are improving the white color and the lumen output of these devices. Strategies Unlimited, a Mountain View, Calif.-based market research firm, is forecasting that the world market for LEDs will be more than $7 billion in four years.
Although they can't replace traditional light sources, LEDs are well suited for innovative, multicolor designs that require the light to graze large surfaces, yet shine exactly where it's needed.
Lamp and ballast technologies. LEDs were just one part of this comprehensive conference and exposition.
T5 and T5HO lamps, which first appeared in North America in 1996 and 1998, respectively, continue their popularity in linear fluorescent, direct/indirect, soffits, valences, wall-mount, and high-bay fixtures. With their high lumen output from a tube that's thinner than either a T8 or a T12 lamp, these lamps slip into small-profile fixtures favored by lighting designers. Although they account for only 10% of the fluorescent lamp market, T5s are growing faster than any other product in the linear fluorescent lineup.
Enhancements also continue for linear T8 fluorescent lamps. Improved barrier coatings reduce the amount of mercury in the lamps. And new releases include energy-saving and high-output models: 28W, 30W, and Super T8 lamps. One manufacturer offers a 25W, 4-foot T8 lamp that can directly replace the 32W lamp on an instant-start ballast. In addition to being energy efficient, it has a 25,000-hour average rated life at 12 hours per start, 2,400 lumens with 95% lumen maintenance, and a CRI of 85.
On the electronic ballast front, the newest models for linear fluorescent lamps offer end-of-life sensing, automatic shut-off, and a soft-start feature that extends life. One manufacturer offers the following four different lines of dimmable ballasts that can satisfy any dimming need.
The step dimming ballast uses a single control lead to change from full output to 50% power with a standard wall switch or lighting relay.
The analog 0-10V dimming ballast is meant for single zone applications where all lamps are dimmed to the same level simultaneously.
The digital dimming system enables multiple light sources — fluorescent, halogen, and incandescent — to function on the same control circuit. The system can handle as many as 250 ballasts in as many as 12 zones with 12 scenes, all on a single, low-voltage communications loop. Setup and programming are handled with a simple handheld remote or wall controller.
The DALI digital ballast system allows ballasts to be controlled or addressed individually, permitting integration with building automation systems. In addition, communications are bi-directional, providing central monitoring of ballast power, dimming levels, and identification of failed lamps and ballasts. Each DALI interface line, or loop, can have as many as 64 addresses, or ballasts.
Both the light-level-switching and analog-dimming ballasts provide impressive savings when joined to schedulers and occupancy sensors. And the two digital dimming products allow for quick configuration of zones and scenes.
Electronic dimming ballasts for HID lamps now provide continuous dimming operating at a higher efficacy, better color control, and no stroboscopic effect. One company offers an electronic ballast that can operate multiple lamps in the 250W to 400W range. The unit can deliver 23% energy savings when paired with 350W or 320W CHM lamps instead of standard 400W metal-halide lamps.
Rapid-start — now called programmed start — ballast models provide precise heating of T8 and T5 linear fluorescent lamp filaments and control the pre-heat time before applying the startup voltage. With this reduced filament stress, lamp life is appreciably extended, which is becoming increasingly important as more automatic switching is performed and performance features are aimed at replacing halogen lamps in display and accent lighting.
Metal-halide lamps are shrinking in size, allowing for more versatile and compact luminaires. Pulse-start metal-halide lamps can replace a standard lamp, resulting in fewer fixtures, faster re-strike time, and improved color uniformity. Ceramic metal-halide lamps, now available in a variety of models, including PAR20, PAR30, PAR38, and T6, provide greater light output, improved color rendering, and limited color shift.
Other issues. Daylighting design practices are maturing. A number of daylighting research centers on the West Coast have grown and expanded their services and projects. On the East Coast, the Lighting Research Center in Troy, N.Y., sends out design- and product-related data through its Daylighting Dividends program.
According to industry specialists, the need to control electric lighting when daylight is available will continue to grow for several reasons. To begin with, LEED initiatives are looking to reduce unnecessary interior and exterior lighting usage and seek to improve occupant productivity and health, incorporating daylight and natural ventilation where possible. In addition, emerging energy codes have put a greater emphasis on energy efficiency, and building owners want their spaces to be more visually comfortable.
However, until now a big deterrent to successful daylighting design has been the lack of specific deign tools. Many skylighting installations go bad — producing excessive light levels and localized thermal discomfort — because a variety of important factors were neglected. Now, an easy-to-use energy analysis program is available that considers construction details of a building, including the lighting and mechanical systems, the proposed skylight design, and the cost of energy.
The Sensor Placement and Orientation Tool software, developed under California's Public Interest Energy Efficient Research project, covers the electric and daylight performance on a building, while also optimizing the location of photoelectric sensor at windows, clearstories, or skylights. Incorrect sensor location is a major cause of poor operation in an automatic daylighting control system.
A daylighting pavilion gathered a significant number of companies that offer shading, fenestration, skylights, and related products. At the same time, the Daylighting Institute (full-day programs) and workshops covered daylighting design practices for both beginner and advanced levels.
The annual Lightfair show is sponsored by the IESNA and the IALD.
The revisions in the 2005 NEC are of particular interest to users of indoor metal-halide fixtures. According to 410.73, for all size lamps, either an enclosed fixture can be specified (with any type of lamp, including Type-E and Type-S) or an open optical fixture can be used with a socket that can only accept Type-O protected lamps. A Type-O lamp has a glass shroud, or containment, around the arc tube.
To an extent, the lighting industry applies this rule to indoor, open metal-halide fixtures that house lamps under 350W, and this new Code requirement is expected to simplify ordering of metal-halide systems. If UL adopts this requirement for MH fixture manufacturers in the future, the rule will apply nationally.