Technology has made commercial lighting smart, starting with automated controls. Instead of flipping switches in a utility closet, facility managers can program lights to activate at designated times and days. They can be linked to occupancy and daylight sensors and controlled by zones on one or several floors. Though this type of system—in which a central control panel choreographs every action and receives feedback from sensors—remains popular, lighting is becoming even smarter.
With a distributed intelligence approach, lighting systems no longer have a single mission control station. Rather, they act more like ant colonies, where members work independently, but in concert with the overall goals of the community. Control zones are smaller and greater in number, and individual luminaires can make their own decisions when to switch “on” or “off,” or dim, thanks to integrated sensors and controls.
One such strategy is to enable individual devices—sensors, dimmers, and luminaires—to behave autonomously, while belonging to a flexible and scalable system, says Dave Ranieri, vice president of Acuity Brands. “You can control [devices] individually, or you can group them together into small networks and control them by room or zone” with a simple CAT-5 cable, he says. “If you change the space, all you have to do is unplug them and plug them in again.”
For its 2012 office renovation in Newport Beach, Calif., DPR Construction chose a mix of controls and LED fixtures to conserve energy and to reach its target of LEED-CI Gold certification. Occupancy sensors were located every six to eight workstations, in hallways, and in common rooms, while daylighting sensors were positioned along the glazed perimeter of the open-plan office to automate dimming. Employees control their tasklighting on their computers or smartphones. The overall light level can be set at 30 percent of full power, thanks to ample daylight, and energy usage has been well below the requirements of California’s Title 24.
With solid-state lighting, systems with a sensor and controller at the individual LED fixture are becoming more common. Enlighted Inc., a Silicon Valley clean-tech startup, offers one such system. Occupancy, ambient light, and temperature data are collected from each fixture through a wireless relay and sent to a central data collector and dashboard, which then sets the control for each fixture. In 2012, a lighting retrofit of the LEED-certified San Jose City Hall outfitted with Enlighted’s system achieved an energy savings of 53 percent.
Implementing control networks can be easier on renovation projects than in new construction, if plenum access is available. Networks with low-voltage plug-and-play or wireless components can be installed during the retrofit. For new construction projects, lighting control networks may be more sophisticated and require upstream planning and coordination in the design-bid-construction process, Ranieri says. Coordinated space planning during the design stage can help ensure that controls are tailored to specific conditions such as daylighting, occupancy patterns, and other factors that affect lighting needs.
The main factor driving these technologies is LEDs, which are well suited for digital control. They turn on instantly and, unlike fluorescents, consume less energy when dimmed. Their long life encourages owners to employ an advanced control strategy from the outset—if the fixtures will last up to 20 years, they may as well optimize their systems with state-of-the-art controls. Ranieri believes LEDs’ greatest benefit is the way that they are driving advancements in control technology. “It’s on a much bigger scale than just changing sources,” he says. “There are so many emerging technologies they are enabling, in the way of optics, communications, and controls,” that are making LEDs more efficient, precise, and responsive.
Meanwhile, regulations are also contributing to the momentum. “The next big driver is the energy codes, which are requiring more and more controls,” says Len Sciarra, a sustainable design leader at Gensler. “Two [code] editions ago … there was very limited control required.” The 2012 International Energy Conservation Code requires occupancy sensors in various space types, including classrooms, restrooms, and private offices. Sensors must turn lights off within 30 minutes of vacancy, and lighting in daylight zones must be controlled separately.
Gensler devised a comprehensive lighting control strategy for the LEED Platinum–certified headquarters of Johnson Controls, in Glendale, Wis. Not only does the networked lighting scheme allow for individual control of workspaces, but it also operates on the company’s Metasys building management platform, which monitors and coordinates building systems across its campus—the next step in controls and integration with HVAC and other building systems. “In the old days,” Sciarra says, “the mechanical system didn’t care if a room was full or empty—only if it was 72 degrees. What you’re able to do now is take information from the occupancy sensor, developed for the light fixture, to inform the chiller and air handler [operations] and ventilation. That’s where you’re getting the integration—it’s all on one computer.”
Ranieri agrees that systems integration is a trend that “the more intelligent buildings” are following, though standardized communication protocols would accelerate it. In addition to interfacing with HVAC, intelligent lighting can also communicate with the electric grid. California’s Title 24 requires retail buildings with sales floors exceeding 50,000 square feet to reduce lighting loads automatically when utilities issue a demand-response signal at times of peak demand; this requirement will soon apply to all commercial buildings exceeding 10,000 square feet.
A 2010 California Energy Commission study investigated the performance of three commercially available lighting control systems (Lutron, Universal Lighting Technologies, and Convia/A Herman Miller Company) during utility demand-response tests. “Relative to normal levels of operation,” the study notes, “demand savings of up to approximately 35 percent were achieved during testing.”
The grid itself is changing to better reap the savings from smart lighting systems. Currently, electricity from the grid is delivered in alternating current (AC) form, while lighting devices use direct current (DC) power. The conversion wastes energy, adds complexity, and creates potential failure points. The EMerge Alliance, an open industry association based in San Ramon, Calif., promotes open standards that would effectively create DC microgrids throughout commercial buildings, eliminating the conversions. EMerge estimates that LEDs integrated with a DC microgrid can gain a 10 to 15 percent increase in efficiency. Wider adoption of DC distribution could spur wider LED adoption, and vice versa.
Ranieri foresees digital lighting systems not just receiving signals from the grid but sending them upstream. “When you take this intelligence and bring it down to a lighting or device level, you can send signals back to the grid that say, ‘If you’ve got to do load shedding, this is a critical system.’ Or ‘This can go down to 50 percent but not below.’ … It’s feasible.”
Installing wired lighting networks can be costly and challenging, particularly in existing buildings. Wireless systems show promise for both retrofits and new construction. EnOcean, a German company, manufactures wireless switches and sensors that harvest small amounts of solar energy to function, eliminating the need for batteries. It spearheads the EnOcean Alliance, a consortium of manufacturers that has developed equipment profiles to operate at compatible radio frequencies, known as the EnOcean standard. The Squaire, a 1.57-million-square-foot hotel, office, and transit complex that opened in 2011 adjacent to Frankfurt Airport, uses 12,000 EnOcean-standard switches and sensors to manage lighting, heating, and room shading systems.
If these systems sound like a brave new world, they are, but they won’t be adopted overnight. While the technology is developing rapidly, new construction has been sluggish, which has limited market penetration. Ambitious control systems remain most attractive for facilities with intensive lighting demand, such as hotels, or even projects that anticipate having longer payback periods, including schools, government buildings, and large offices. As construction picks up, however, the shift will accelerate. In a few years, hyper-intelligent lighting could seem just average.