4 FM quick reads on LED
1. Smart Uses for LEDs
"LEDs are not magical." That's one quote from a recent tradeshow in Chicago for lighting specifiers. While the main conversation was not aimed squarely at facility managers, there were a few tips and food for thought. If there was one take-away for facility managers it was to consider the strengths and weaknesses of a lighting source and match it appropriately with the lighting application.
Here are two misconceptions lighting designers have experienced from their clients (you!) in regards to using LEDs in commercial applications:
- LEDs are great, everywhere! When a small project with a focused application for LEDs has great success, facility managers can be tempted to want to deploy LEDs everywhere. But their attributes — chiefly their highly directional nature — and operating characteristics, make them unsuitable for a wholesale deployment without careful consideration for the needs and challenges of the application.
- LEDs last forever and are maintenance-free! While it is true that quality LEDs from proven manufacturers have shown very long lives and high-reliability, the LED module is just one component affecting maintenance. As one presenter said, there are still birds in the world, there is still dust. Lenses can still discolor with age and other components in the luminaire can fail.
Other challenges posed by LEDs are brightness and glare problems, but lighting specifiers report that facility managers are so taken with LED technology that they're willing to be more lenient on these points than perhaps they should be. Color matching is another hurdle with LEDs, as color temperatures can vary between manufacturers, or even between batches of the same product. The industry is responding to this by developing color-tunable LEDs and also seeking to develop new standards to describe the quality of the LED light output as perceived by the human eye.
LED technology has evolved to the point where it is being deployed in a broad range of applications. Some of the best ways to deploy the technology still seem to be in highly-directional applications, as well as to highlight architectural features, where the lack of radiated heat is a benefit, in very tight spaces, or on bridges or other areas where vibration is present, as LEDs are less affected by this than other light sources.
For more pros and cons of LEDs, check out this.
2. Improve The Efficiency Of The Heating And Cooling Distribution System
Today's tip from Building Operating Management comes from Daniel H. Nall of Flack + Kurtz. After available environmental resources have been fully exploited to reduce heating and cooling requirements, the next strategy is to improve the efficiency of the heating and cooling distribution system for the building.
One approach to reduced transport energy is to utilize water, to as great an extent possible, as the heat transport fluid for the building. Transport of heat by water is 4 to 10 times as energy efficient as transport by air. The trade-off for reduced transport energy, however, is the decreased effectiveness of free-cooling strategies in water based distribution systems. All water distribution systems, therefore, will be most effective in extreme climates, those that are too hot and humid to provide free cooling, or so cold that waterside free cooling is frequently effective. For these climates, a dedicated outdoor air system with heat recovery, for ventilation and dehumidification, along with a primarily hydronic sensible heating and cooling distribution system, such as fan coils, chilled beams, or radiant panels is likely the most energy efficient system selection.
For peak load operation, the efficiency of distribution systems can be significantly improved by minimizing the pressure drop against which the system must operate. For hydronic systems, pipe sizing and selection of valves is critical for minimizing flow pressure drop. Similarly, for air distribution systems, duct sizing, selection of aerodynamic flow accessories — such as turning vanes — and optimal sizing and selection of dampers are critical to minimizing pressure drop. Coils and other heat exchangers should be selected for reduced pressure drop on both the primary and secondary sides of the exchanger. Minimized approach temperature should also be considered in the selection of coils and heat exchangers. The ideal distribution system, whether air or water, should feature reduced pressure drop along with maximized temperature differential across the system.
3. Consider exterior lighting upgrades as savings source
Today's tip is to look at your exterior lighting as a source of savings. Turning off exterior lighting loads for institutional and commercial facilities is the most effective way to save energy, but it might not address the lighting needs of the general population. People need some form of exterior illumination to feel safer and more secure. Beyond functional lighting, people also need lighting that enhances the nighttime atmosphere to encourage activity and make spaces feel inviting.
Every year, building codes and green building programs require that facilities further reduce energy consumption. Advances in technology have reduced loads for interior building lighting, but only recently have manufacturers considered extending these energy savings to outside.
Because organizations use exterior lighting to provide security and aesthetic appeal, it is no surprise that managers hesitate to turn off outside lights. But the lighting system for a parking lot designed in 1970 — or even 2000 — probably is outdated by today's standards.
Replacing the key components of a high-pressure-sodium fixture with LED lamps might reduce energy consumption and deliver a reasonable payback of two-four years — or, with rebates, instantaneous payback. Managers should be sure to specify LED sources from reputable, established manufacturers who have controlled binning standards, proven heat sinks and fixtures specifically tested and designed for their LEDs.
The most efficient LEDs are cooler white. In exterior applications, cool blue color temperatures also can result in reduced allowable lighting levels. But at least in the United States, cooler light — usually anything greater than 4,100 Kelvin (K) often is perceived as uncomfortable, sterile, and institutional. Building facades appear more inviting when illuminated with a warmer light — 3,000-3,500 K — that also has a high color rendering index (CRI). A CRI greater than 80 makes the finishes of materials and objects appear more true and rich.
Managers also should take care should to select a lamp that is compatible with the project's geographic location and the connected controls. Fluorescent lamps do not like low temperatures. Dimming ballasts also generally are not fond of temperatures below 50 degrees. Induction lamps are more compatible in cold environments, tend to produce less glare, and have one of the longest life spans. But they are not dimmable, and their distribution patterns can be difficult to control through fixture optics.
4. Planning Successful Lighting Retrofits
I'm Dan Hounsell, editor of Maintenance Solutions magazine. Today's topic is, successful lighting retrofits.
Lighting retrofits are increasingly popular because of the bottom-line benefits they offer institutional and commercial facilities. San Diego State University undertook a series of lighting retrofits in recent years, and it has specified light-emitting-diode (LED) technology for five different spaces on campus, including a lecture hall, a gymnasium, and a restroom with low ceilings that required the high-quality light that LEDs could provide.
Along with an improved quality of light, dimming capabilities in the lecture hall and the ability to run gymnasium lights at 60-65 percent capacity have contributed to the university's positive experience with LEDs, says John Eaddy, associate director of physical plant.
"Our experience has been outstanding," Eaddy says.
He has found the initial cost of LEDs to be higher than the cost of more traditional fixtures, but the reduced maintenance requirements and potential for energy savings have created a potentially lucrative payback for the university. Eaddy also looks for rebates from the state or local utility to help achieve a quicker return on investment.
"When we're going out and doing these projects, we're realistically looking for no more than a 2-1/2-year payback," Eaddy says. "We've been able to quantify and actually meet that goal, 9 out of 10 applications."
Eaddy hopes the success the university has had with T8s and LEDs for indoor applications translates to exterior applications. The university has retrofitted six parking structures with 32-watt T8 lamps and is conducting a test on the use of LEDs in campus streetlights.
Lighting projects continue at San Diego State, and contributions from the university's students will play a pivotal role, given their past interest in helping collect data for planning retrofits. As Eaddy discovered, the students' passion for working together with the physical plant department benefits the facilities, their operations and the university as a whole.
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