Electro/Telecom Industry Trends
February 2004
Increasing Energy Efficiencies With Lighting Controls
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Lighting controls have come a long way from the simple on-off snap switch that most people are familiar with. Many options are now available that are designed to decrease the amount of energy waste by eliminating unnecessary light usage. From dimmer controls and timers to occupancy sensors, these controls help commercial and home users alike meet their lighting needs while minimizing energy consumption.
Lighting plays an integral role in any building’s operating performance. For example, in large buildings, where electric illumination is used extensively, the heat given off when electricity is converted to light can increase the load on air-conditioning systems, further increasing energy usage. That is why lighting control systems are a key part of the design and construction of many new commercial buildings. By using a variety of automatic and manual controls, these building are better able to reduce the use of unnecessary lights and therefore lower their energy bills.
One type of automatic control used extensively in newer buildings is the occupancy sensor. At one time available only as a mechanical sensor that reacted to the opening of a door, today’s occupancy sensors use ultrasonic or infrared technology to detect the presence of people through movement, heat, or sound. Lights are only made available when there are people in the room to use them, and are automatically turned off or dimmed a few minutes after the sensor stops detecting the presence of people.
Timers are another way to control light output. In their simplest form, timers can be used to automatically turn lights on and off at fixed times. More complex kinds of timers can be used with other types of technologies. For example, timers with dimmer controls allow building managers to automatically dim or raise light levels at predetermined times based on known usage patterns in order to save energy.
Dimmer controls offer another way to save energy by providing users with a way to either automatically or manually lower light output levels. Once only available for incandescent lamps, dimmer controls are now also being used with fluorescent lamps, thanks to the availability of new electronic ballasts that provide this functionality. This is especially important in office spaces, where fluorescent lamps are used extensively.
Combined with photosensors, dimmers can also be used to adjust the output of electric lighting based on how much daylighting (sunlight entering a space through windows and skylights) is available. Photosensor-dimmer controls maximize the effectiveness of daylighting, so that electric lighting output is increased as outside light diminishes. These controls can also reduce electric lighting output when more daylight is available.
Used on their own, photosensors are applied effectively to control light in outdoor areas. Here, they can be used to prevent lighting use during daylight hours. Motion sensors can also be used with photosensors, keeping lights turned off during daylight hours and only illuminating them at night when people are present.
Today, government agencies and lighting manufacturers are at work creating new and more efficient lighting control systems. One type of system being developed is known as demand responsive lighting. At the core of the system are load-shedding ballasts that allow for the reduction of fluorescent lighting power requirements during times of peak energy demand. Used in combination with dimmer controls and daylighting, demand responsive lighting promises to help building owners save money by reducing power usage at times of the day when energy costs are higher. Just as importantly, it offers a way to help stabilize the electrical grid, an important consideration during times when the threat of rolling blackouts remains imminent.