Efficiency Goals
May 1, 2009 12:00 PM, By Donald Graham
Education institutions can save energy with smart lighting choices.
- Controllability
Significant advances have been made in lighting control. The days of turning light switches on and off manually (or forgetting to do so) are nearly gone. Occupancy-sensing and lighting-level technologies enable school buildings to more closely match lighting levels to actual needs. They also limit use to only those times that spaces are occupied.
Advanced lighting controls even can be programmed to bring several levels of light to different areas in the same space. For example, the front of a computer classroom may be awash in light when the teacher uses a whiteboard, while rows of pendant fixtures above computer monitors at student workstations are lighted dimly.
Another lighting-control factor affecting schools is the move toward simplicity. If the controls are too complex for teachers to master, the system won't be used, and the benefits are lost. Therefore, simplifying lighting controls has become a high priority. When a lighting system requires little human intervention and is self-regulating, an educator can focus on teaching and other important tasks.
In addition, some control systems benefit maintenance programs by monitoring and calculating the expended service life of lamps and alerting workers when the appropriate replacement time arrives. They also will pinpoint the location of burnt-out lamps and monitor power consumption.
- Lighting equipment
Most lighting equipment and control manufacturers have embraced sustainable and green products, and the advances made have been not just in efficiency. Technology advances in types of lighting fixture materials, such as high optic lens and the combination of various styles of fixtures — pendants and recessed — also reduce glare and improve uniformity. These advancements deliver the appropriate level of illumination to where it is needed.
Providing electronic dimming ballasts is the optimum strategy for energy savings and controlling the desired light level for each activity. Dimming ballasts will increase installation costs, but as technology improves and demand increases, costs will drop. Dimming ballasts would be the preferred choice when used with daylight harvesting controls to provide gradual lighting adjustments.
A suitable alternative to full-range dimming is electronic step ballast technology. The ballast can control light levels through programmed increments. This can be effective in many applications where reduced light levels are required but where fine control, as afforded by full-range dimming ballasts, is not needed. Conference rooms and some classroom spaces are typical applications. However, if daylight controls are used, changes in light levels may be less subtle with step ballasts. Either full dimming or step ballasts with programmed circuitry will work well with occupancy sensors; even with frequent on/off starts, the lamp life can be maintained.
New lamp technology is producing lamps with a smaller diameter; T-5 lamps are a mere 0.67 inches in diameter. This newer fluorescent technology with higher light output and smaller diameters offers improved fixture efficiencies. Combining this new technology with the improved light-reflecting surfaces of reflectors and optic system materials contributes to greater overall fixture efficiencies.
With all the new energy-efficient technology and equipment, education administrators have a prime opportunity to work with their architects to increase the use of natural light and be in a good position to recommend the most efficient lighting strategy for their schools.
Graham, LC, LEED AP, is an associate with Erdman Anthony, Harrisburg, Pa., a multidisciplinary firm that specializes in infrastructure engineering and support services.
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