How to Calculate the Energy Efficiency of Lighting in an Industrial Facility
Efficient lighting is a great way to save energy in an industrial facility. Lighting is relatively easy to improve compared to other energy efficiency measures such as adding insulation and improving the HVAC system. To calculate the efficiency of a lighting design, you must not only look at how much electricity is used, but whether energy efficiency can be increased by using different lamp types, rearranging their placement and implementing automatic controls.
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Instructions
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Instructions
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Determine how much energy is currently used on lighting. The architectural drawings should include a lighting schedule that lists the specific lamps used in each room. Obtain all power ratings for all of the lamps from the manufacturer data, and add them together to obtain the total power used by lighting.
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Evaluate possible savings from changing the types of lamps. The efficiency of industrial lights varies based on how much light they give off (given in lumens) in relation to how much energy they consume (given in watts). The efficiency of lights range from under 20 lumens per watt for incandescent lamps to up to 185 lumens per watt for low pressure sodium lamps.
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Evaluate the placement of lighting fixtures. An important part of evaluating the efficacy of lighting in a facility is to ask whether lamps are appropriately placed, or whether fixtures can be rearranged to provide a brighter environment for an equal amount of power. The intensity of light decreases exponentially in relationship to distance from the source.
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Evaluate use of automatic lighting controls. It is just as important to turn lights off when not in use as it is to have efficient light fixtures. Because occupancy patterns within industrial facilities are sometimes unpredictable, occupancy sensors will help save energy in rooms with irregular traffic. Rooms exposed to windows may benefit from daylight controls, which can save energy by dimming or turning off lights when there is sufficient daylight streaming in.
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Tally up the estimates of possible savings. The energy-efficiency of lighting for a facility is given by the energy that is used by the current lighting arrangement divided by the energy that would be used for an optimal lighting strategy. The number this yields represents the fraction of energy spent on lighting that unnecessarily goes to waste.
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