Efficient Lighting Technology
Upgrade your Industrial Lighting
Older fluorescent lighting systems use T12 lamps, which are easy to identify because of their large diameter tubes (1.5 inches). An effective way to upgrade lighting in areas with T12 lamps is to keep the existing fixtures, but replace the T12 lamps and magnetic ballasts with T8 lamps and electronic ballasts. By changing lamps on a one for one basis, savings of up to 40 percent can be achieved. T8 lamps are thinner (1 in. tube diameter), produce higher quality light and use less energy than T12 lamps. The light output of a T8 lamp will also decline slower than T12 lamps; at 40 percent of their rated life T12 lamps produce 80 percent of their original output whereas T8 lamps produce 90 percent. Longer lamp life and less lumen depreciation mean lower maintenance costs. Employee productivity increases because the light quality is higher.
Magnetic v. Electronic Ballasts
T12 Lamps use magnetic ballasts to maintain the correct current in the lamp, while T8 lamps require electronic ballasts to operate. So switching ballasts is necessary when upgrading to T8 efficient lighting technology. High frequency electronic ballasts (20,000 to 50,000 Hz) perform better and are more reliable than magnetic ballasts (60Hz). The higher frequency allows the lamp to operate more efficiently as less input wattage is required for the same lumen output.
A major consideration when selecting ballasts is the ballast factor, which is the percentage of lumens from a lamp that is operated by the actual ballast being used, compared to the lumens from the same type lamp powered by standard benchmark ballast. Magnetic ballasts operate at about 90% ballast factor, while electronic ballasts can be designed to have a low (around 70%), normal (around 85 to 95%), or high (above 100%) ballast factor. The lumen output of a lamp is calculated by multiplying the ballast factor by the lumen rating of the lamp. A lower ballast factor also means less input wattage is needed to power the lamp. During a retrofit, money and energy can be saved by selecting the correct ballast for higher or lower lumen output/energy use as required by the space being lit.
Retrofitting also provides an opportunity to clean or replace the fixture's reflector. The old reflectors have a coating that may have degraded significantly over time or may be dirty and need cleaned. Most existing reflectors are made of steel and coated with white paint that initially reflects 89% of the light striking it. Over time the reflectivity may degrade, but if cleaned will likely approach 85% efficiency. If the coating has degrading too much, a new aluminum specular reflector (86%), aluminum white paint reflector (91%) or aluminum Miror 4 reflector (95%) may be installed. Aluminum white paint reflectors diffuse light, while mirror 4 reflectors efficiently redirect the light to different locations in the space. A more efficient reflector means more light reaches the intended area, which may allow the use of low ballast factor ballast or fewer lamps in each fixture.
Lenses and Louvers
The lens is the plastic or glass material covering the fixture opening. They can allow the light to pass through unaffected, or can control the distribution pattern of the light. During a retrofit the lens can be cleaned or changed to a more efficient type. Changing the type of lens allows the fixture to provide a wider and more uniform distribution. This may enable the use of fewer fixtures in a space or fewer lamps in each fixture. These modifications result in lower energy consumption while maintaining or improving light levels.
High-intensity-discharge (HID) light systems are used in the majority of high-bay applications (indoor spaces with high ceilings.) High-bay areas are found in warehouses, manufacturing facilities, parking garages, large retail stores and athletic/entertainment arenas. Metal halide and high pressure sodium are the two most common HID lamps and operate by striking an arc through vaporized metal. The development of high intensity fluorescent lamps and effectively shaped, high efficiency reflectors allow fluorescent fixtures to be used instead of HID lighting in high-bay areas.
HIF light fixtures feature higher lamp and ballast system efficacy and greater fixture efficiency, which means more light is produced using less electricity. Replacing HID with HIF high-bays can total up to a 45-65 percent reduction in energy usage and cost.
Longer Functional Life
Both HID and fluorescent lights lose some of their light output as they age. This is known as lumen depreciation and with HID lighting it can approach 40 percent over the lifetime of the lamp. Fluorescent lamps will lose less than 10 percent of their light output. While HID lamps are rated to last 20,000 hours, lumen depreciation will require that the lamp is replaced to maintain acceptable light levels. A fluorescent lamp will maintain the required light level for almost all of its 24,000 hr lifetime.
More Control Options
While HID light sources must warm up for about five minutes, fluorescent lighting systems turn on instantly. This allows for a fluorescent lighting system to be turned on and off in response to a control system such as occupancy sensors. Fluorescent high-bay fixtures also allow for greater control of the light level produced by using multiple circuits so individual lamps in the fixture can be turned on or off. Dimming ballasts can also be used to vary the light levels without the increasing the fixture's wiring complexity.
Incandescent lamps are typically used for down lighting in commercial facilities. While they light up instantly and provide a warm light with excellent color rendition, they are extremely inefficient. Most incandescent lamps produce around only 15 lumens per watt because only five percent of the energy consumed is converted into light. Incandescent lamps also have a short lifespan of around 750 to 2,500 hours. This means the operating cost of an incandescent lamp is high due to both inefficient energy consumption and the labor time needed for replacing them as they frequently burn out.
Compact Fluorescent Lamps
A compact fluorescent lamp will produce the same amount of light as an equivalent incandescent, but use approximately 25 percent of the wattage. The majority of compact fluorescent lamps are also expected to last 10,000 hours or more. They can replace incandescent used for most applications: table lamps, down lights, sconces, recessed cans, flood lights, track lighting and even general lighting.
Lighting Emitting Diodes
LED lamps save even more energy and last significantly longer than compact fluorescent lamps. They also emit no UV and contain no mercury. A particular advantage over compact fluorescent lamps is their ability to dim smoothly through. While more expensive than compact fluorescent lamps, prices are coming down rapidly as this lighting technology improves.
LED light sources use a semiconductor diode to produce light instead of the tungsten filament in incandescent lamps. The diode has positively and negatively charged areas inside of it. By applying a voltage to the diode with the positive end hooked up to the negative area and the negative end hooked up to the positive area, the electrons inside become excited and jump from the positively charged to negatively charged areas. This process is very efficient; most of the energy consumed is emitted as light instead of heat.
The two most common uses of LED's are for lighting retrofits are for use in exit signs and traffic signal lights. All new traffic signals and exit signs are almost exclusively manufactured with LED's. LED's are also increasingly used in signage and linear applications that used to be provided by neon lights.
LED's are the most efficient way to power an exit sign as they consume 90 percent less energy than incandescent exit signs. LED exit signs require around 2 watts of input wattage, compared to up to 40 watts for an incandescent exit sign. Although the wattage is lower relative to other lights in a building, since they are on continuously, LED exit signs can pay for themselves in under 4 years. They also save on maintenance due to their extended lifetime compared to incandescent lamps, further reducing the payback period. LED exit lights are typically designed with strips of LED's where the light is reflected out of the face of the exit sign or the LED's can be placed directly behind the face of the exit sign for illumination. During a lighting retrofit, either a new sign can replace an older sign or a retrofit kit where an LED lamp is screwed into the existing base can be used. Although the retrofit solution is less expensive, the new LED exit lamp may not have adequate illumination.
Traffic Signal Lights
Most cities in the United States have replaced their incandescent traffic lights with LED units because they save energy, are brighter and last for much longer than incandescent or halogen lamps. A traffic light using 3 100-watt incandescent lamps operating 24 hours a day will use 2.4 kilowatt-hours per day. If power costs 8 cents per kilowatt-hour, one traffic signal costs about 58 cents a day, or about $210 per year. If there are eight signals per intersection, that's almost $1,683 per year in electricity costs. LED bulbs consume 15 or 20 watts instead of 100, so the electricity costs are lowered by 80 percent. LEDs arrays fill the entire hole and have equal brightness across the entire surface, making it brighter. LED traffic signals last up to five times longer than incandescent signals, this means that technicians are dispatched less often, which lowers labor costs.
LED's mounted on flexible materials can be used to quickly retrofit a wide variety of signs that use neon lamps. LED's use 80 percent less energy and last five times longer than neon lighting. LED's can operate without flickering in a wide variety of temperatures and even cold start instantly. LEDs also light the sign better by eliminating shadows and hot spots on the face of the sign.
Lighting controls reduce the hours of operation of the lighting system by turning the lights off or down when full light output is not necessary. This can save 25 percent or more in most building areas.
Lighting controls take many forms such as occupancy sensors, photo-cells, timers, dimming systems and or more sophisticated controls systems that can be tied into a building automation system. The type of controls chosen is dependent the specific needs of the areas being lit by the lighting system.
Primary Control Strategies
Occupancy sensing: the lights are turned on and off or dimmed by sensing motion
Learn more about Lighting Upgrades and Retrofits.