A Reintroduction to Induction Lighting
- By Christine Beitenhaus
- 07/01/08
About 30 years ago a new lighting technology became available without much fanfare, but it only gained popularity after being reintroduced in the 1990s. Induction lighting technology, similar to fluorescent lighting, “offers a life span of up to 100,000 hours, outlasting 100 incandescent bulbs, five HID lights, or five typical fluorescent lamp changes,” according to information from Full Spectrum Solutions. With induction lighting’s obvious benefits of a long lifespan and little-to-no maintenance, are college campuses rushing out to switch over?
How It Works
Induction lighting is based off the principle that a gas discharge through magnetism can produce light. Basically, mercury vapor, located in the discharge vessel, is excited with the creation of a magnetic field inside the lamp vessel, producing invisible ultraviolet light. Visible light is then produced when the ultraviolet light passes through a phosphor coating on the surface of the tube. There is no electrical connection within the bulb, thus the generation of light is achieved through electromagnetic induction.
Benefits and Drawbacks
According to Dae Hur, HID product manager, strategic marketing for Philips Lighting Company, the lack of electrodes means, “the system’s life is much longer than conventional light sources. If the system components are designed properly, in terms of thermal management, then the system average rated life will be about 100,000 hours.” This long life translates into lower maintenance, a benefit to colleges who often recoup their initial costs through time from use of these lighting systems. Often, the only drawback to these systems is the initial cost, so it has been important for colleges and cities using induction lighting to show the rate of return. “Sacramento Municipal District does a lot of case studies, and they were trying to show the payback in the long life,” commented Steve Beede, market development manager at Lutron. “They were showing the energy efficiency and the long life. It does have a high price to it right now, and they are trying to show the benefits in the payback in the life of the bulb.” Joelle Kolhagen, marketing director for Full Spectrum Solutions, added to that point. “It’s maintenance free; you’re not going to have to mess with it once it is up. There aren’t the maintenance charges of someone going out and having to change your bulbs,” she explained.
Induction lighting technology has other benefits. Induction lighting can be turned on and off without waiting, like a typical halide fixture. Philip’s QL induction lighting system “is instant on/instant restrike, which is helpful during power outages,” stated Hur. Most induction lighting systems also have very good optics. “It replicates natural daylight, so it isn’t glowy orange,” said Kolhagen. The phosphors are similar to a traditional fluorescent system’s, providing great white light of CRI 80 with a choice of color temperatures. Beede also mentioned that an induction light puts out more lumens than an individual fluorescent light, although “a typical fluorescent fixture will have six lights compared to the one incandescent light in its fixture.”
Where It Works
According to Beede, induction lighting operates well at a range of temperatures, including lower temperatures. He suggested, “These systems work great for outdoor applications, places where you don’t want to be doing a lot of maintenance. This includes places where you want to have a good deal of light, like parking garages.”
Kolhagen noted that Full Spectrum Solutions works with the University of California, Davis, which has recently been redoing some parking garages. “We have different options for controlling [our induction lighting systems],” she stated. “Some of the fixtures have daylight sensors so that the light is off during the day.” The fixtures installed in the UC Davis parking garages can be dimmed to 50 percent when no one is using the facility. The lighting returns to 100 percent when someone comes in. “The parking fixtures do go down to 50 percent, so you still have the light for safety issues. At 50 percent, the light is still pretty bright,” she added.
Induction lighting fixtures are often going to be used in place of sodium or metal halide fixtures. This means you will see induction lighting showing up in streets, walkways, garages, tunnels, and wet environments. Induction lighting has even made the jump to indoor lighting.
Who Is Using It
Colleges who have been using induction lighting systems include UC Davis; Bryant College in Smithfield, RI; Lebanon Valley College in Annville, PA; and Texas Lutheran University in Seguin, TX. Another university that has been installing and testing out induction lighting systems is the University of Michigan.
Moji Navvab, associate professor of architecture for the University of Michigan, stated that the University was first attracted to the use of induction lighting because of the light output, life of the source, and color temperature. The University is currently using wall-mounted pack lights for entries and exits, pathway and street lighting, and loading docks. He stated that they are hoping to use induction lighting systems in parking structures soon.
Navvab and the University have also done tests on the lights in the Sustainable Design Research Laboratory, which is within the University of Michigan’s Taubman College of Architecture and Urban Planning. They’ve tested “the amount of lumens or light output and the duration of exposure required or needed to make the noticeable difference for the users’ vision conditions under nighttime conditions.” He went on to explain, “You do not need 100 Lux (lumen per m.-sq.) or 10 Fc (lumen per ft.-sq.) illuminance levels to illuminate the pathway at night, and these sources, given their specific spectral characteristics, do make a major visual impact at night for viewing and color recognition.
“We have a very special data collection system that allows us to record the lighting condition at night in a dynamic way while walking or driving,” he continued. “We measure the scotopic and photopic illuminance simultaneously and evaluate the lighting conditions at night.”
So far, their testing has not found any drawbacks. Navvab also pointed out that what originally attracted the University to induction lighting systems has become a benefit as well. “Also, I have to say they do fully comply with the EPA and other regulations that already exist for CFL and LED as well.”
While the University of Michigan already has the lighting in several different applications, Navvab was quick to say that there are more applications they would like to try. These include, “combining with solar and wind, which is in progress right now. We have tested a prototype in the city of Ann Arbor for parks.” Other applications include a wall-mounted system with a sensor and dimming options within the City Farmer’s Market.
Future Uses
While induction lighting has come a long way since the early 1990s, expect it to continue to develop and show up in new places in the coming years. When discussing where the University of Michigan would consider using induction lighting in the future, Navvab suggested bringing the lighting indoors with smaller sources and dimming options.
Beede agreed. He stated, “In order for it to get into a multi-purpose space, you’re really going to need to get a full range of control on it.” Based off the lamp output, Beede also felt induction lighting will make a jump to retail in the future. “You’ll see it in a lot of high bay applications, warehouses, big box retailers where on and off are all you need.”
Kolhagen also felt that induction lighting will also make it into many more applications in the future. “I definitely see it expanding,” she said. “We’ll be seeing it in a lot more applications, especially retail.” Of course, she mentioned, “It’s always been there [on the market], but there is some lighting technology that is getting more news. We’re going to see a number of people going towards [induction lighting] in the next year or so.” Other technology, like LED, is out there, “but it doesn’t feel like it’s there yet because there’s price point and optics issues.”
If more universities and colleges who have been testing induction lighting recently feel the way the University of Michigan does, then her predictions may just come true.