Lighting Systems
General Description
Lighting systems are the second largest users of electricity in commercial buildings. Industrial lighting systems are large electricity users in magnitude, but generally close to 10% of a manufacturing plant’s total electricity use. In fact, many of the same energy conservation opportunities apply to both commercial buildings and industrial facilities. Industrial lighting systems are considered to include warehouse and similar high-bay construction lighting systems. New innovations in florescent lighting and occupancy sensors make these types of systems prime candidates for energy conservation measures, with energy savings of up to 75% possible in some cases.
Modern lighting systems (i.e., luminaires) include the fixture, reflectors, lamps, ballasts, controls, and sensors. The following table describes common lights and their typical industrial application(s).
| Lamp Cost | Efficacy (lumens/W) | Lamp Life (Hours) | Uses | |
| Incandescent | low | 12-20 | 500 | Replace with compact flourescent. |
| Halogen | low | 16-35 | up to 8000 | Sometimes used as backup lighting. Low efficacy makes this a poor choice for primary light source. |
| Compact Flourescent Lightbulb (CFL) | medium | 60-72 | 6000-15000 | Almost every lighting application has a flourescent solution. Use CFLs in place of incandescent bulbs. |
| T12 Flourescent | low | 40-60 | 6000-20000 | T12's are being phased out. Replace these with high efficiency T8 or T5 |
| T8 Flourescent | low | 70-100 | 6000-20000 | This is the standard floursecent lamp for office, low-bay, and even high-bay applications. |
| T5 Flourescent | low | 80-100 | 6000-20000 | Highest efficiency common flourescent lamp. Use in offices, low-bay, and high-bay applications. |
| Mercury Vapor | low | 50-55 | 24000-30000 | Low cost/high life lamps are common, but low efficacy make these prime candidates for replacement evaluation. |
| Metal Halide | medium | 65-115 | 6000-20000 | Very good light rendering and good efficacy makes this a good choice for high and low bay applications. Compare to high output flourescents. |
| High Pressure Sodium | medium | 130-150 | 10000-24000 | Great efficacy, but average to good light rendering mean that sodium lamps are not good for high detail lighting needs. These are generally used in outdoor applications. |
| Low Pressure Sodium | high | 183-200 | 14000-18000 | Highest efficacy, but high lamp costs and poor light rendering mean that these are almost exclusively used outdoors. |
| Induction Lighting | high | 80-92 | up to 100,000 hours | Induction lights are basically flourescent lights without electrodes. Good color rendering, high efficacy, and very long life make these an interesting emerging technology. |
| Light Emitting Diode | ? | ? | ? | Emerging technology. Potential to be used in all applications due to high lamp life and high efficacy. |
Potential Energy and Cost Savings Opportunities:
The below energy conservation opportunities or energy efficiency actions (EE ACTIONS) are provided as a partial list of potential savings opportunities in your plant. They are grouped as no-to-low cost, moderate cost, and long-term cost investments. Consider each for your plant and feel free to contact us for clarification or any assistance you may need in assessing specific projects.
No-to-low cost investment
EE Action: Maintain proper illumination
Lighting levels should be appropriate for the function of the space. These acceptable levels are established by the Illuminating Engineering Society (IES). It is common to find lighting levels that are 50-200% greater than required. Where applicable, de-lamping of existing fixtures is a no-cost solution that saves significant electrical energy. Light level meters are inexpensive and should be used to survey the amount of lighting at the working surfaces.
EE ACTION: Proper maintenance and cleaning
Dust on lamps or discoloration of old lenses reduces lighting levels. Regular cleaning of light fixtures and scheduled maintenance of lighting systems can increase lighting performance, extend lamp life, and reduce fire hazards.
Moderate investment
EE ACTION: Use task lighting
Some tasks require more lighting than the general space. Rather than maintaining an overall light level in the general space, it saves energy to use localized task lighting while lighting everywhere else as required.
EE ACTION: Get rid of those old T-12 lamps
The T-12 lamp (1.5” diameter fluorescents) was the standard for numerous applications and are being phased out. Today, many energy efficient lamps are available for direct replacement; or, sometimes complete luminaire (fixture, reflectors, and lamps) replacement is most economical.
EE ACTION: Replace magnetic ballasts
Most magnetic ballasts are also being phased out and not available for purchase. Electronic ballasts generally use only a fraction of the energy as compared to magnetic ballasts; so, even with a moderate capital cost, the replacement of magnetic ballasts can have short payback periods. Upgrading lamps at the same time can save even more energy.
EE ACTION: Reduce lighting operating time with improved lighting controls
Occupancy sensors, dimming controls, time clocks, and a myriad of other controls are available for most lighting systems. In some cases, simply subdividing a lighting system with multiple circuits can allow you to reduce energy usage by turning off lights in an unoccupied or partially occupied space.
EE ACTION: Retrofit or replace entire lighting systems
Lighting technology has improved significantly over the past 5-10 years. Especially In lighting systems with long runtimes and high output levels, retrofitting old, inefficient equipment with highly efficient equipment can have payback periods less than two years. Frequently occupied areas are prime candidates for lighting retrofits. Energy reductions of 60% or more are possible.
EE ACTION: Use fluorescent lights in low-occupancy spaces
Warehouse, storage, and satellite spaces often have low occupancy rates, some as low as 10%. With typical high-bay construction, and even with the use of high efficacy lamps, like high-pressure sodium, the lighting energy is wasted when during unoccupied times. With warm-up times of up to 15 minutes, it’s not feasible to turn these lighting systems off if the space *may* be occupied soon. New advances in high output fluorescent lamps, with instant-start capabilities, are finally providing an energy efficient alternative for these spaces. In conjunction with occupancy or other sensors, it is possible to provide proper lighting levels instantly for a safe working environment. Spaces can now light only the occupied areas and conserve energy elsewhere. In some applications, energy savings can be 75% or more.
EE ACTION: Install daylight sensors with dimmable lighting
Many industrial facilities have skylights installed, but their lights still operated at full-load to ensure proper lighting levels during cloudy days. Daylight sensors can be used to measure the amount of illumination received from natural sources and then dim ballasts or turn off some or all of the artificial lights as needed.
