It’s common knowledge that one of the easiest ways to save energy is to shut off lights when they are not in use. Even so, the lighting controls market accounts for a fraction of the overall lighting industry. The market is small, despite the benefits of control technology, because in the past energy consumption was not a high priority. In addition, frequently turning lights on and off reduces the lifetime of light bulbs by as much as three times. LED lighting eliminates traditional lifetime issues and is aligned to enable a rapid growth in the lighting controls market.
On its own, quality LED lighting can provide energy savings of 30% over fluorescent, and 65% over HID fixtures. When combined with controls and sensors, LED fixtures can further reduce energy consumption without compromising lifetime. As an example, the Dole Foods Atwater California sub-zero cold storage warehouse documented a 95% reduction in energy use with LED fixtures and smart controls.
Because, LED lighting is a solid-state technology with lowvoltage operation and instant turn-on, it is intimately compatible with digital control and sensor technologies. But navigating the process of controls selection and integration can be complex. Here are a few basics that everyone should understand.
Types of Sensors
Motion sensing is the most valuable way to maximize energy savings, by turning lights off as soon as people leave. There are multiple technologies available and cost depends largely on technology selection and how it is implemented. Some of the current technologies include:
• Passive infrared: senses body heat;
• Ultrasonic: senses objects;
• Sound: senses noise.
Systems that combine multiple technologies into a single system provide more robust solutions, but also increase system costs.
Daylight harvesting is growing in popularity and is very useful in applications that have significant window and/or skylight exposure. This approach senses when natural daylight is available and automatically reduces the use of artificial lighting. When combined with occupancy sensors, this strategy can provide a powerful solution for gaining additional energy savings from the lighting system.
The location of sensors can also have a big impact on performance for both occupancy and daylight harvesting strategies. Sensors can be mounted directly to the fixture or can be standalone. Standalone sensors can be placed in an optimum position for controlling fixtures, including locations where there may be no fixture. The drawback is that these standalone sensor installations require additional wiring and power. Better performance is usually associated with a higher density of sensors and carefully placed sensors, while costs favor a more dispersed solution. This density/cost dynamic can lead to a wide range of performance levels depending on whether density or cost takes precedence. Care must be taken in the design phase to ensure the correct value is delivered to the end customer.
Wired vs Wireless
Once the sensor types and locations have been determined there are several interconnectivity considerations. One is the link between the sensor and the fixture, and the other is the link between the sensor/control system and an energy management system.