By: Craig DiLouie
For decades, outdoor lighting was controlled using an astronomical time switch or photosensor. This allowed the luminaire to be turned on or off based on time of day or daylight. Typically, luminaires were controlled at the circuit level with no individual luminaire control. Several years ago, commercial building energy codes changed all that. Twenty-four states currently have a commercial building energy code in place at least as stringent as ASHRAE/IES 90.1-2010/2013 and the 2012/2015 International Energy Conservation Code (IECC). These codes require dusk-to-dawn lighting be turned on/off using a photocell. During operation, lighting must be automatically reduced by at least 30% after business operations or in response to occupancy. Façade/landscape lighting must be operated using a combination photocell/time switch that turns off between midnight or business closing (whichever is later) and 6:00 a.m. or business opening (whichever is earlier).
Coincident with more complex control requirements are several other significant advances. LED lighting is rapidly gaining adoption in the stationary outdoor lighting sector; its instant-on operation, relatively convenient dimmability and inherent compatibility with intelligent controls make it well suited to sophisticated control. Incorporating intelligence allows more complex control strategies that can result in better performance and deeper energy savings. Wireless communication enables networking, permitting centralized control as well as measuring and monitoring.
“It’s an exciting time in the outdoor space,” said Terry Headrick, director of marketing and product management, Eaton (eaton.com). “LED technology is finally allowing us to address all applications, from 100W-equivalent to 1,000W and higher products. Even more exciting is that we are really only scratching at the possibilities of what controlled lighting can bring.”
The LED revolution is generating numerous retrofit opportunities. Distributors interested in maximizing revenues from retrofits should consider appropriate lighting controls as part of the solution. At a minimum, the control solution could follow a similar path as that required by energy codes. That is, turn the lighting on/off based on daylight or curfew, and reduce dusk-to-dawn lighting afterhours. Beyond that, additional capabilities can be gained with intelligent wireless lighting such as detailed programming for higher energy savings and data retrieval for energy management and maintenance.
“Distributors should be pushing for controls from the start and tying the added cost to the overall fixture price and front-end energy-savings calculations,” said Bryan Pike, manager, ESCO sales, Legrand Building Control Systems (legrand.us). “Controls are a much harder sale post LED retrofit. If I were a distributor, every time I looked at a parking lot, I would be thinking that I could make $20 to $40 each for selling LED retrofits with controls.”
Control Opportunities and Trends
The two biggest opportunities and trends identified by manufacturers are dimming and information.
LED lighting is readily available with dimmable drivers. Dimming facilitates deeper energy cost savings, code compliance, and possibly reduced skyglow and light trespass. Additionally, it can extend LED product life, a significant potential boost to dimming’s value proposition.
“The biggest sales opportunities for outdoor lighting controls will come from outdoor occupancy sensors that provide dimming control and fixture control modules with integrated occupancy and daylight sensing,” said Mike Crane, senior product manager, Hubbell Control Solutions (hubbell-automation.com).
“External fixture control modules that are compliant with ANSI C136-41 [seven- and five-pin] twist-lock receptacles also provide large sales opportunities,” he continued. “Offering the new twist-lock receptacle is another sales opportunity. To ensure controls are included in outdoor retrofits, distributors should consider packaging or at least promoting controls with LED retrofit kits.”
Dimming is ideally paired with embedded intelligence, allowing more complex control strategy implementation. Time schedules and daylight are used to turn the outdoor luminaire on or off at certain times. An embedded intelligent astronomical time clock allows the schedule to be offset based on the application. It also allows varying levels of lighting reduction based on the time of night and/or occupancy. For example, luminaire output could be brightest at sunrise/sunset and automatically reduce the rest of the night.
Incorporating wireless communication enables remote centralized programming of all luminaires connected within the network, including zoning as individual luminaires or groups. It also offers metering/monitoring capabilities to produce information that can be used for ongoing energy management and maintenance. For example, monitoring with automated alerts can readily reveal “day burners” and other problems remotely, thereby improving maintenance efficiency.
“Some of these systems can offer real-time access 24/7 and provide the user with data analytics from the cloud or a dedicated server on energy usage and maintenance requirements,” said Headrick. “They can provide real-time alerts when there is a fault or failure at a light point that may need immediate attention. Wireless systems also allow the user to create multiple zones, allowing customized operating characteristics. Many of these things can’t be done with a stand-alone sensor system.”
The wireless system is typically based on a series of gateways (or network managers) that manage, monitor, and receive information from nodes (or fixture modules) embedded in or mounted on the luminaires. The gateways can be accessed by software or app on a PC, web portal, or mobile device. A majority of networks utilize a mesh or tree architecture, which features repeating and self-healing nodes. Luminaires can be programmed to operate independently or within groups. By eliminating wiring, these systems can pose a lower installed cost.
Two potential emergent trends are color-tunable luminaires and integrating sensors such as security and audio into the luminaire.
“Street and parking lot lights are spaced every 200´, and many have power all the time,” Pike explained. “In the case where there is no central control of a group of lights, there are many options for additional value. Video monitoring, motion sensing, and gunshot detection systems are being deployed in some cities.”
“The technology is definitely here today,” Crane noted. “An example is a security camera with an output interface that can be used as an input signal to a fixture control module. When the camera detects an event, it sends a signal to the fixture control module, which then flashes the fixture. If the module is a wireless module, it could broadcast the flash command to all fixtures in the area. Demand for this technology is quite high, especially for customers with high-dollar inventory in outdoor lots, such as auto dealerships.”
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