Published In January 2002
With energy costs continuing to skyrocket, warehouse managers are frantically seeking new methods of reducing lighting costs. Estimates that as much as 20 percent of total electrical bills may be attributed to lighting large spaces present opportunities for lighting contractors capable of reducing costs without compromising high-quality illumination. Meanwhile, new products coupled with traditional cost-saving systems are providing efficient solutions. Near- and short-term cost reductions have been achieved in a variety of commercial applications with the introduction of electronic ballasting, pulse-start metal halide lamp systems, and compact T-8 fluorescent lamps. Couple this new technology with dimmable ballasts, motion sensors, light harvesting, and an ongoing maintenance program, and savings go directly to the bottom line. Fluorescent tubes are preferable in environments where illumination is directed down long, narrow aisles surrounded by storage racks. Studies show that the installation of compact T-8 fluorescent tubes driven by electronic ballasts may reduce energy consumption by one-third or more. Since T-8 lamps last longer and deliver more consistent lumen output over the course of their lives than their T-12 cousins, end-users can expect lower maintenance costs as well. Also, more efficient output means fewer fixtures are needed. Given these factors, the cost of retrofitting could be recovered in two years. In locations demanding spot lighting, such as retail warehouses with open areas and high ceilings, a new option is pulse-start metal halide lamps. This source unites the energy and cost efficiencies of older high-pressure sodium (HPS) technology with color rendition of metal halide. Historically, HPS systems have provided excellent light output, longer lamp life, and higher efficacy than probe-start metal halide. But they produce a hazy, yellow light that is suitable only where color quality is not a consideration. Conversely, metal halide has delivered white light at the cost of operational inefficiencies. The shortcoming of metal halide is a shorter life-span, lower efficacy, and two-thirds the lumen maintenance of HPS. The product of an alliance between Advance Transformer and the major lamp manufacturers, new pulse-start metal halide lamp systems are significantly more efficient and have solved the yellow light problem. What’s new? The introduction of an igniter as a component of the ballast that replaces the lamp’s internal starting probe. Advance Transformer claims that the new ballast-lamp systems boost lamp life and lumen output by 25 to 50 percent. The lamps have increased color rendition index (CRI) of up to 85, an increase of 30 percent. Lamp manufacturers achieved the improvements by creating new arc tube chemistry and redesigning lamp shapes. The result: better light output, high lumen maintenance, and long life. Efficacy of the new units is 90 to 100, compared to HPS at 100 to 125; Lumen maintenance is within 10 percent of HPS. “Based on our evaluation, the manufacturer’s claims of increased efficiency are correct,” said Lei Deng, a research specialist at the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute, in Troy, N.Y. Though new products are driving energy saving plans, other components of a master plan can increase efficiency. Dimmable ballasts have been on the market for some time, but new technology has improved their viability. In the past, lamps had to operate at 100 percent of capacity before they could be dimmed. These days, new ballasts allow dimming ranges between 5 and 90 percent without first achieving maximum output. Couple these ballasts with light harvesting techniques that replace artificial light with natural light, and Mother Nature adds to the cost savings. An historical challenge with light harvesting has been to develop sensors that adapt to the difference between shafts of sunlight illuminating specific areas and diffused light on cloudy days. Differing levels of light intensity made measuring input, which triggers dimming, difficult to meter. However, Peter Boyce, a professor at LRC, is testing a newly created diffusion system coupled with a built-in measuring gauge that will obviate these distortions. “It works in the lab,” he said, “so now we need to test it in the field.” When motion sensors are added to the light harvesting-dimmable ballast equation, a third, energy-saving element enters the picture. A myriad of challenges still exists in the lighting of cavernous spaces. However, the industry is responding with viable alternatives that provide an informed electrical contractor with a cafeteria of reasons to discuss cost saving with energy managers. LAWRENCE is a freelance writer based in Bozman, Mont. He can be reached at firstname.lastname@example.org.