Outdoor lighting controls
While there are exciting advancements in wireless lighting controls for interior applications, outdoor controls are also undergoing a mini-revolution. Traditionally, outdoor lighting control was relatively simple. A typical scheme featured a controller providing an automatic on-off system based on time of day of an astronomical time switch or a 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. While LEDs continue to displace other light sources in many applications (including outdoor lighting), they do not eliminate the need for control. Fortunately, intelligent multi-level control is well-suited to LED lighting due to the inherent controllability of the digital source.
Energy codes and outdoor lighting control
The American Society of Heating, Refrigerating, and Air-conditioning Engineers/Illuminating Engineering Society of North America (ASHRAE/IES) 90.1-2010, Energy Standard for Buildings Except Low-rise Residential Buildings, 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—reduced by 30 per cent after normal business operations (based on schedule or occupancy).
Parking garage lighting power must be reduced by at least 30 per cent based on occupancy, with control zones limited to 334 m2 (3600 sf). Daylight harvesting and separate controls for day-transition areas (i.e. entrances and exits) must be implemented.
Created to save energy, these simple requirements have had a big impact on the world of outdoor lighting control, increasing demand for sensors, individual luminaire control, and controllability. This has increased demand for good design and commissioning.
While not all local codes have adopted requirements as stringent as ASHRAE/IES 90.1-2010, the products and experience developed around compliance provide ready-to-go solutions for both new construction and existing buildings.
Control options
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, or photosensors as needed. Therefore, the lighting would be controlled at a panel if the lighting is dimmable; control wiring must run the luminaires.
A better solution might include luminaires with attached control devices providing 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. For example, in a parking lot, this solution would be appropriate for area lighting, while signage and security lighting could be operated during dusk and dawn using a photosensor or a limited time of night that is based on a schedule.
The most advanced solution in terms of capabilities is an integrated wireless control system that provides an on/off mechanism and dimming implementing daylight-, occupancy-, and time-based strategies. In a parking lot, 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. Options are generally limited to passive-infrared (PIR) detection. These options may expand in the future to include options for digital imaging (i.e. non-recording video), which offers more precise detection in the dynamic outdoor environment.
Wireless lighting control for outside
Again, 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 provides further advantages of two-way communication and individual luminaire control.
Two-way communication creates two distinct capabilities. Operators can recalibrate the system, change schedules, and distribute commands from a central point. Many wireless control solutions incorporate intelligence enabling the capture of performance data, which can be reported to a central point for maintenance, performance, and security purposes. Systems such as these are supported by a web-based interface, enabling operators to remotely visualize real-time performance, set schedules, zone luminaires in groups, and generate custom reports optimizing management of outdoor lighting as an asset. Some offer GPS-location capabilities, allowing operators to understand what is happening at each control point and where that point is—this can be highly useful for maintenance of street, public space, and large area lighting.
Whether the lighting control application is wireless devices inside or use outdoors, selecting the optimal solution involves evaluating necessary control sequence of operations, need for multi-level control, configurability, and data for predictive maintenance, energy analysis, and security. The selected control solution should be able to deliver the desired feature set.
During decision-making, one should consider outdoor lighting controls not in isolation, but rather as 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. In existing building lighting upgrades, controls should be considered as part of a lighting and control solution supported by utility rebates recognizing controls as well as lighting.
Conclusion
With intelligence, communication and the ability to collect data, today’s lighting can be viewed as systems delivering sensing, decision-making, control, and prediction. Electrical professionals involved in the selection and delivery of lighting controls should stay educated on what is new and how it works to continue offering the best value to clients.
Craig DiLouie, a lighting industry journalist, educator, and marketing consultant, is principal of Calgary-based ZING Communications. He is the education director for the Lighting Controls Association. DiLouie can be contacted via e-mail at cdilouie@zinginc.com.
