Flipping the Switch
The latest energy-efficient lighting technologies are all designed to provide better light for less cost.
Tuesday, March 06, 2012
By Lori Lovely
There’s more than one way to do anything, believes Larry Leetzow, president of Magnaray International, a division of World Institute of Lighting and Development Corp. in Bradenton, FL. One way to reduce absenteeism while increasing employee productivity is to provide workers with control over their environment through lighting.
Employee productivity may be a “soft issue” that’s hard to quantify, but lowering electric consumption through energy-efficient lighting is clear cut. With quality lighting appropriate for the application, as determined by a lighting designer—per the recommendation by the Illuminating Engineering Society, Leetzow says businesses can expect to see 25–30% in energy savings on top of increased productivity.
According to a US Department of Labor, Bureau of Labor Statistics study in 2010, Americans spend more time at work than any other activity—other than sleeping—and the hours spent at work continue to rise every year. Not only are we working longer hours, but more people are working in offices or other workstation environments that require artificial light. Providing properly illuminated work environments conducive to productivity is one way to make money; using energy-efficient lighting is a way to save money.
The Quality of Light Is Not Strained
Light is visually perceived radiant energy. Quality light incorporates the right amount and the right color of light with glare control.
“Energy efficiency involves visual quality,” explains Leetzow. “It’s about quality versus quantity. It’s the most important thing. If you have quality lighting, you have energy efficiency.”
The right kind of lighting makes it possible to reduce the amount of light by one-third, thereby using one-third less energy, while still being able to “see details.”
Quality light addresses color, glare, uniformity, and control. “You want a 4,100 Kelvin temperature lamp,” indicates Leetzow, “because that will provide a balanced red-green-blue spectrum; it’s neutral.” Light rated higher than 4,100°K is blue and cold, while light rated less than 4,100°K is red and warm.
When the University of Kansas needed lighting for its new sustainable Center for Design Research, projected to be the first LEED (Leadership in Energy and Environmental Design) Platinum building in Lawrence, KS, it chose Halo LED (light-emitting diode) downlights from Cooper Lighting, a subsidiary of Cooper Industries PLC, a global electrical products manufacturer. The Energy Star-qualified recessed housing features an All-Pro Rl7 LED module trim that provides benefits such as savings, ample light output, easy installation, and extended life up to 50,000 hours, resulting in less maintenance. The dimmable lights also provide a warm white color temperature of 3,000°K, delivering over 600 lumens while consuming less than 15 W.
Portfolio LED downlights from Cooper Lighting come in a range of color temperatures from 2,700°K to 4,000°K. Color variation is within the three-step MacAdam ellipses, ensuring color consistency. The 4-inch and 6-inch round and square aperture Energy Star-qualified lights feature a diffused optical system for light control and low aperture brightness. The wall-wash fixtures feature a two-stage reflector system that produces high levels of vertical illumination on the wall with minimal source brightness. A curved transitional lens design further reduces LED source brightness, distributing light more evenly.
While Cooper Lighting is introducing new LED fixtures, John Noel, of Energy & Environment, says what’s old is new again: T8 lights.
“T12 [lights] and magnetic ballasts were replaced with T8-electronic, especially in California and Hawaii,” he says. “The vast majority of fluorescents are high-efficiency F32 T8s that use a standard 32-watt T8 bulb and electronic ballast.”
But the new F28, which uses the same standard bulb in a 4-foot fluorescent, when matched with a high-efficiency electronic ballast, now draws 48-W (as opposed to 58-W) and still produces within 4% of the same light.
“It’s more vibrant—whiter and brighter than the old T8—because we bumped up the CRI [color rendering index],” says Noel.
Noel also mentions a retrofit Energy & Environment did a few years ago. He acknowledges a “slight lumen loss” of 4–6%, but says there was an appreciable gain in light, due to the color rendering. The F28s produced “the same amount of light, better-quality light, using less energy.”
Another economic advantage of the F28 is that it has better life expectancy than its predecessors. Noel compares its rating of 28,000 lamp hours to F32 and T12 ratings of 20,000 lamp hours. It costs more, he admits, but “there’s a big bump in life and a 4-watt-per-lamp savings; you pick up an extra couple watts because the ballast efficiency is enhanced.”
Glaring Reality
Glare, a common issue in offices, causes visual discomfort and fatigue. Lighting designs for offices must take computers and other office equipment into consideration, as well as sunlight from windows and skylights. Aiming 70% of available light up for ambient lighting and 30% down for task lighting is one method of glare control. Indirect ambient light, bouncing light off the ceiling, can eliminate unwanted reflection and save energy.
One successful approach in solving lighting design problems is the task/ambient concept. By providing a low level of ambient illumination for most areas and strategically placing task lighting in work stations, it conserves energy while providing the necessary amount of light where needed.
Standards established by the Illuminating Engineering Society of North America, the recognized technical authority on illumination, dictate 50–75 foot-candles of light at workstations and 20–30 foot-candles for ambient lighting.
“Daylight is a light source,” states Bill McShane, director of sales for the Sustainable Lighting Division of Philips Lighting. To make use of it, he says new buildings are being constructed differently, from geographical orientation to the inclusion of light wells and skylights. New designs that include atriums, window access, and less-enclosed space leverage natural daylight.
When supplementing daylight with artificial light sources, the key is uniformity. Uniformity is important because the eye works on the brightest spot it sees, Leetzow explains. “Eyes react to a bright window or other peripheral light. You can bleach the retina due to ambient light.”
It’s all about the contrast level: more intense light creates more shadows and contrast, which cause fatigue. “You need uniformity of light so the eye doesn’t fight intensity differences,” he adds.
To achieve visually balanced light, some offices incorporate the use of parabolic louvers in fluorescent troffers. Daylight harvesting systems with sensors near windows that send signals to dimming systems can adjust the light appropriately.
Linear fluorescents reduce or eliminate shadows in offices, Leetzow says. Conversely, LEDs don’t have proper diffusers to scatter or break up light. “LED task lights are effective if the glare point is below the eyes and the output is smooth and even, but fluorescents work better for ambient lighting,” he says. “It all has to do with positioning and the type of light.”
Control Freak
Integrating a control system to dim or turn off electric lighting with daylight harvesting can also significantly reduce energy consumption. Dimming saves money—as much as 30–40% of lighting costs. Standard office lighting is always 100% on or off, and when lights are dimmed instead of being fully on, savings can be gained.
Personal control allows individuals to customize the level and performance of lighting to suit their individual needs. Depending on the occupant, lighting levels can be adjusted, whether it be the focused light needed for high-tech industrial situations—where young workers stare at computer monitors all day long—or when less light is needed.
Personalization of workspace lighting can be limited by the management because luminaires can be programmed by the management and the facility manager can set limits or fine-tune areas, or rely on a universal default level. Features can be selectively deactivated where impractical—such as turning off daylight harvesting in conference rooms that have no windows. Whatever the settings, personal automated sensors detect light levels and determine occupation of space by high-frequency motion detection that is sensitive enough to detect breathing and air movement.
The benefit of using lighting in task-oriented applications is the ability to position light where you want it. By bringing lighting down to the area, light sources can be positioned closer to the user’s desk, meaning that at work stations, lights no longer have to be placed in the ceiling. Instead, the customer can have a customized, workstation-centric lighting system.
Spare Change
Change is difficult, especially when it’s expensive. The price point for LEDs is much higher, in part because the technology is still in its infancy. As such, the return on investment (ROI) depends on the installation—although a reduction in the staff needed for implementation (LED’s eliminate the need to hire an electrician) payback can be seen in three to five years.
A key factor in the surge of interest in LEDs is LEED. But LED isn’t the only option for energy-efficient retrofits. Cooper Lighting introduced a series of four Metalux fluorescent retrofit kits designed to meet today’s energy guidelines and improve light quality. Consisting of architecturally inspired designs, they offer a wide range of features that save energy, time, and money when compared with T8 or T5 luminaire options.
Incorporating the latest optical, energy-saving lamp and ballast technology in order to use less energy without any loss of light, the kits feature Ready-Set, the industry’s first patented captive and secure self-tapping screws. With pre-wired ballast and assembly, they’re easy to install in under 10 minutes and fit into most existing luminaires, so upgrading troffers and parabolics as shallow as 3 1/2 inches is possible. The kits provide up to 60% energy savings over standard three- or four-lamp T12 or T8 luminaires.
LEED is one form of encouragement to adopt an energy-efficient lighting system. Incentives from federal and state governments are other inducements. McShane points to new IES guidelines and energy code changes for new construction that will “change the industry,” but he sees 99% of the opportunities in retrofit.
“Between lack of new construction, inventory of existing buildings, and legislation regarding energy usage like we’re seeing in New York City, a lot of buildings need to be updated,” he says. As tenants move out, he believes buildings will have to be updated or leases will be affected.
“The barrier to LED technology is cost,” admits McShane, “but it’s a growing concept. The technology is rapidly changing; they’re emitting more light, wattage is increasing. They have longer life and controls make an LED solution more cost-effective because it reduces the kilowatt draw. Controllability is appealing.”
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Photo: Terridian
For LEDs, ROI depends on installation. |
In the future, McShane envisions new efficient designs that reduce kilowatt draw even more. Fortunately, he adds, LED technology is being “future-proofed.” When a lamp and ballast are changed out, they are no longer thrown away; they’re upgradeable. It’s one of the things Philips has been working on. Since 2007, the company has spent billions in LED research.
Another innovation looming in the not-too-distant future is a computer system with lighting that could be used to direct traffic or lead to open spaces in a parking garage.
“Sensors can be added to the control system to direct traffic,” envisions McShane. “You have to keep an open mind to coming technology.”
As a one-stop shop that offers turnkey services and maintains direct ties to lighting manufacturers, Philips designs, installs, and maintains systems for its customers.
“LED is not a panacea,” indicates McShane. “It’s not for every application. Standard [light] sources are still popular, but they’re in decline as LED for offices is on the rise. The LED high-bay is widely accepted, but still costly. However, it provides benefits such as reduced maintenance, longer life, proper footcandles, and its lumen output is growing. It will outpace the efficiency of standard sources soon.”
LED prices may be coming down and lumens per watt increasing dramatically, but Noel believes that the price is still too high and applications are too few.
“LED makes sense for flood lights, Christmas lights, cool environments, street lights, truck lights, and directionals—specific niches—but it’s hard to get low-priced good distribution with LED.”
Noel believes the future lies in hybrid solutions for mixed use.
“It’s the way to go,” he says.
Noel mentions a country club in Atlanta that recently underwent a hybrid lighting retrofit that dropped the energy consumption of just its clubhouse from 185,000 kWh to 31,000 kWh. LEDs were used in the floodlights, chandeliers, and sconces. Downlights recessed in the ceiling were both LED and CFL (compact fluorescent lamp) in 20 W and 60 W incandescent. Despite those savings, Noel believes that “for the best energy efficiency, we need comprehensive solutions that include building control, HVAC, insulation, and windows.”
In the Cold Light of Day
In a hybrid application for a supermarket, Noel would use fluorescents around the perimeter and in the ceiling, while using LEDs as cooler lights to illuminate items. In fact, according to Joe Martin, vice president and general manager for Precision-Paragon, the latest trend in LED lighting is retrofit for cold storage distribution facilities.
“The best opportunity is for distributors of food products such as pizza and ice cream, where freezers are kept at negative 20.”
In those conditions, LEDs work better than traditional light sources because they are “almost instantly on,” explains Martin, while linear fluorescents can take up to an hour to turn on in the cold temperatures. In fact, the cold storage environment helps heat sinking, an issue with LEDs that makes them less suitable for some other applications.
Another benefit is integrated controls that allow the management to reduce burn hours.
“You can capture tremendous savings,” says Martin. Not only does it save money when the lights are off, it also reduces the cost of the refrigeration load because lights create heat.
The controls also allow management to focus light on specific aisles with individual fixture control.
“Different users want different things, but most don’t need all the aisles lit if no one is in them,” he adds.
Although the LED fixtures are typically more expensive, Martin says a reasonable investment-grade payback can be expected for a retrofit.
“Payback is under three years—an average of two to two-and-a-half years, with a 40% ROI. It reduces wasted energy and the associated cost.”
In fact, it’s been so well-received because of good performance that Precision-Paragon is rolling it out to other facilities as well.
“Several are already taking advantage of it,” says Martin. “The performance advantage in the freezer makes it the best technology for this application. The challenge is that other technology works in other applications at lower cost. Linear fluorescents have a lower first-cost production in commercial and industrial applications, especially in retrofit, where the energy reduction must pay for all costs—as opposed to new construction, where you already have labor costs built in.”
Author's Bio: Writer Lori Lovely focuses on topics related to transportation and technology.
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