Light on your wallet: top lighting solutions for managers. (Ductape).
Managers should investigate "smart" fluorescent light fixtures with integrated sensors to help provide energy savings. The Ergolight office lighting and control system from Ledalite provides work-specific lighting with a three-lamp fixture in each cubicle. Two lamps provide down light on the task and one lamp positions light on the ceiling. Dimming ballasts, connected to a daylight sensor and an occupancy sensor, operate the lamps. Occupants control light level from their computer.
LaMar Lighting (www.lamarlighting.com) manufactures a series of Occu-Smart fixtures equipped with occupancy sensors, which can keep lamps at a low light level and switch to a high level during occupancy. The fixtures are ideal for corridors, stairwells, restrooms and other areas where maximum light levels are nor constantly required.
Automated lighting controls decrease hours of use, reducing kWh and cost, and occupancy sensors control lighting in spaces not continuously occupied. The newest occupancy recognition controls require no manual adjustments, cutting costly commissioning time. These adaptive sensors contain microprocessors that analyze activity and adjust both sensitivity and time delay settings to meet the needs of the controlled area. Sensors now incorporate zero-crossing relays to prevent the problem of in-rush current that occurs with electronic ballasts rated with total harmonic distortion (THD) less than 20 percent. These relays sense the 60 Hz waveform of the power line and delay closing the contacts until the next zero-crossing where no current flows, preventing in-rush. Many major lighting product manufacturers offer such automated solutions.
Photocells are electrical switching devices that operate when light falls on them, used to turn outdoor lighting systems on and off at dusk and at dawn. The least expensive photocells use cadmium sulfide cells, but they degrade from exposure to sunlight and lose sensitivity after only a few years of service. The resulting energy savings are reduced when photocell sensitivity is degraded.
Electronic photocells using solid-state, silicon phototransistors that do not lose sensitivity can be used to teplace cadmium sulfide cells. The solid-state photocells last longer and easily return the initial cost investment with energy and labor savings. Managers and owners seeking to trim outdoor lighting expenditures would be best served to seek solutions affording more flexibility and cost-effectiveness.
Cove lighting systems can be upgraded with T5 fluorescent lamps (5/8-inch diameter) and their ballasts, which are 12-18 percent more efficient than T8 lamps. They provide higher light output in confined applications and more usable lumens per watt.
All lamps in the standard T5 family have the same surface brightness. No matter what length lamp is used to fill out the length of the cove (549, 849, 1149 or 1449 mm), brightness is uniform. The high bulb-wall brightness, however, limits use to applications where the bulb is not visible or in high ceilings. A flexible, new ballast from Advance (www.advancetransformer.com) can power one or two standard T5 lamps of any wattage (14,21,28 or 35 watt).
For brighter coves and other indirect lighting applications, T5HO lamps are recommended. They have the same physical measurements as the lower wattage, standard T5 lamps, but provide higher lumen output. Half the number of lamps can be used, because they generate nearly twice the light output of the standard T5 and nearly twice the light output of T8 or T12 systems.
The surface brightness of T5HO varies with various wattages (24, 39, 54 or 80 watt) and the lamps operate on different currents, so each lamp wattage requires a unique ballast. They are about 10-15 percent less efficient than standard T5 lamps and up to 8 percent less efficient than T8 systems.
New compact fluorescent lamps (CFL) that use mercury in combination with other metals to form an amalgam are a major improvement. The amalgam makes the lamps less sensitive to the effects of temperature and position. Most "triple" tubes are amalgam.
Screw-base compact fluorescent lamps include three models from MaxLire (www.maxlite.com) that can be used in high-ceiling applications to replace 200-300 watt incandescent lamps. Each model has an efficiency of 65 lumens-per-watt (LPW) and a rated life of 10,000 hours.
A new four-pin, 57-watt rapid-start CFL, rated at 4,300 lumens is designed for high ceilings. Several electronic ballasts are available, and Osram-Sylvania offers a matching lamp and ballast system.
Two major improvements in metal halide lamps are driving the trend to white light by replacing high-wattage incandescent and halogen sources. Ceramic arc tube metal halide (CMH) lamps from Philips use the same ceramic material used in high-pressure sodium arc tubes, which eliminates color shift and spectral variations.
CMH lamps are available from 50 to 400 watt with either warm (3000K) or cool (4000K) color temperature with color-rendering (CRI) ratings up to 92. Applications include downlights for lobbies and atria of hospitality spaces, and lighting merchandise.
Standard metal halide in the 175-1000 watt range make up 70 percent of existing applications and will be replaced by CMH or pulse-start (PS) lamps, such as models from Venture. Pulse-start arc tubes are started by a high voltage pulse (4 kV).
The best PS lamp performance results from formed body arc tubes, which have uniform geometry and higher fill pressures. Improved temperature control reduces lamp-to-lamp color shift and other design changes result in up to 80 percent higher lumen maintenance, up to 110 lumens-per-watt lamp efficacy, 50 percent faster warm-up and re-strike, longer life, and more consistent lamp-to-lamp color.
New light-emitting diode (LED) exit signs are energy-efficient (5 watts), cavity-lighted units aesthetically pleasing for any building application. New generation LEDs are higher quality, longer life and about 30 times brighter than first generation devices. Because of their long life, LED exit lights also reduce maintenance costs. A new solid-state, light-emitting capacitor exit sign design from LightPanel (www.lightpanel.com) uses one-quarter watt and is rated for 30-year life.
While rising energy costs and the need to be more energy efficient pose challenges to owners and managers, implementing even the smallest lighting changes can make a huge difference.
John Fetters (firstname.lastname@example.org) is a certified lighting efficiency professional and principal of Effective Lighting Solutions, Inc., a lighting consulting firm specializing in energy-effective lighting solutions.
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|Publication:||Journal of Property Management|
|Date:||May 1, 2003|
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