Outdoor lighting controls is undergoing a mini-revolution that offers new design and selling opportunities while challenging electrical professionals to stay on top of technological change.
Traditionally, outdoor lighting control was relatively simple. A typical scheme featured a controller providing automatic ON/OFF based on time of day (using an astronomical time switch) or daylight (photosensor). The luminaires were typically controlled at the circuit level with no individual luminaire control.
Commercial building energy codes imposing requirements for more advanced sequence of operations, coupled with greater controllability of LED lighting, have resulted in outdoor lighting control design becoming more sophisticated.
Energy codes and outdoor lighting control
ASHRAE/IES 90.1-2010, the national energy standard, requires all outdoor lighting be controlled by a photosensor. Building façade and landscape lighting must be controlled by a time switch that turns the lights OFF at some point during the night.
The energy standard also requires all outdoor lighting power—other than building façade and landscape lighting, but including advertising signage—be reduced by at least 30% after normal business operations based on a schedule or occupancy.
Parking garage lighting power must be reduced by at least 30% based on occupancy, with control zones limited to 3,600 sq.ft. Daylight harvesting and separate control for daylight transition areas (i.e., entrances and exits) must be implemented.
These simple requirements, created to save energy, have had a big impact on the world of outdoor lighting control, increasing demand for sensors, individual luminaire control and controllability. This in turn has increased demand for good design and commissioning.
While not all states have adopted an energy code at least as stringent as ASHRAE/IES 90.1-2010, the products and experience developed around compliance provide ready-to-go solutions for other states as well as existing buildings.
Today’s product offering from manufacturers offers electrical professionals a spread of choices for outdoor lighting control with distinct capabilities.
A lowest-cost solution for outdoor lighting may include circuit-level, contactor-based switching of luminaires grouped in functionally appropriate control zones, each with its own schedule and/or photosensor as needed. The lighting would be controlled at a panel. If the lighting is dimmable, control wiring must be run the luminaires.
A more robust solution might include luminaires with attached control devices that provide individual multi-level occupancy- and daylight-based luminaire control. The photosensor activates the lighting, while the occupancy sensor raises/lower light output and electrical input based on occupancy. In a parking lot, for example, this solution would be appropriate for area lighting, while signage and security lighting could be operated dusk to dawn using a photosensor of a limited time of night using a schedule.
The most advanced solution in terms of capabilities is an integrated wireless control system that provides ON/OFF and dimming implementing daylight-, occupancy- and time-based strategies. In a parking lot, for example, the area lighting could be zoned and controlled as individual luminaires or groups, while the signage lighting could be controlled on a schedule and security lighting dimmed as individual luminaires or groups.
Occupancy-based multi-level outdoor lighting control is a relatively new phenomenon. Currently, options are limited to passive-infrared (PIR) detection. These options may expand in the future to include options for digital imaging (non-recording video), which offers more precise detection in the dynamic outdoor environment.
While the LED continues to displace other light sources in many applications including outdoor lighting, it will not eliminate the need for control; in fact, it facilitates the adoption of greater flexibility. Intelligent multilevel control is well suited to LED lighting due to the inherent controllability of the digital LED source.
Wireless lighting control
Wireless control demand and technology continues to advance at a rapid rate due to its advantages of allowing devices to communicate without costly installation of wiring. It offers further advantages of two-way communication and individual luminaire control.
Two-way communication creates two distinct capabilities. Operators can calibrate/recalibrate the system, change schedules and distribute commands from a central point. Many wireless control solutions incorporate intelligence enabling the capture of performance data that can be reported to a central point for maintenance, performance and security purposes. Systems such as these are supported by a web-based interface that enables operators to remotely visualize real-time performance, set schedules, zone luminaires in groups, and generate custom reports that can optimize management of outdoor lighting as an asset. Some offer GPS-location capability allowing operators to understand what is happening at each control point and where that point is, which can be highly useful for maintenance of street, public space and large area lighting.
Because it’s a relatively young technology, it’s unclear as to what the best and most reliable methods are at this point. ZigBee, 6LoWPAN, proprietary and cellular approaches are all on in various stages of implementation.
What’s best for your application?
Selecting the optimal solution involves evaluating necessary control sequence of operations, need for multilevel control, configurability and information needs for predictive maintenance, energy analysis and security. The selected control solution should be able to reliably deliver the desired feature set.
During their decision-making, electrical professionals should consider outdoor lighting control not as an isolated system but part of the total building lighting control system. With the integration of luminaires and controls, the traditional view of these as two separate items is changing to one that regards lighting as a system. In existing building lighting upgrades, controls should be considered as part of a lighting and control solution supported by utility rebates that recognize controls as well as lighting. With intelligence, communication and the ability to collect data, today’s lighting can be viewed as systems that deliver sensing, decision-making, control and prediction. Electrical professionals involved in the selection and delivery of outdoor lighting controls should stay educated on what’s new and how it works to continue offering the best value to clients.