Wireless Lighting Controls Make Retrofits Practical PER Buildings Program The Problem Lighting accounts for about 35 percent of the electricity used in California's commercial buildings. Digital lighting controls that allow daylight harvesting, occupancy control, and per- sonal control (allowing individuals to adjust lighting in their own areas) could reduce that percent dramatically. However, retrofitting these systems into existing facilities is not often done because it is expensive and disruptive. The Solution An innovative wirelesslighting-control, monitoring, and manage- ment system developed by Adura Technologies is easy to install, cost-effective, and can provide significant energy savings (Figure 1). It eliminates the costly and time-consuming installation of control wiring and can be easily installed by facilities personnel or contractors. The technology was originally developed at the Cen- ter for the Built Environment at the University of California at Berkeley (UCB) with funding from the California Energy Com- mission's Public Interest Energy Research (PIER) Program. With venture capital funding, it is now being developed by Adura. The system has been successfully installed in several pilot applications and will be fully commercialized by 2009. Features and Benefits The heart of the system is Adura's wireless relay transceiver/ microprocessor unit. These devices, called LightPoints, are installed inside a fluorescent light fixture and can control the ballasts individually or in zones. The system's capabilities are similar to those provided by existing Digital Addressable Lighting Interface products, but without the need for wiring. The LightPoints are linked together wirelessly and communi- cate in a configuration known as a mesh network. In a mesh network, data are routed among the different Light- Points so that there are multiple, redundant paths through the network, allowing communication between two LightPoints that might have no direct link to each other because of some transient problem. It also makes it possible for large distances to be covered, despite limited transmitting power, because the LightPoints can hand off data to one another. The system is tied together by web-based software that con- figures and sends commands to the proper devices. The sys- tem currently includes wireless, battery-powered wall switches and can also be controlled via software. Future plans call for /* \ we LAN = local area network. Technical Brief WWW.energy Ca.gov/research wireless occupancy and photo sensors, and switches that don't require batteries but instead make use of the mechanical en- ergy of pushing the switch. The benefits of this wireless approach include energy savings through economical application of multiple lighting-control strategies, ease of installation, and the ability to reconfigure the system as the needs of the space change. Saves energy. Energy savings come from the ability to provide scheduling, occupancy, daylight, and personal control. In 2005, a prototype installation of personal controls involving 33 light fixtures at a UCB building showed a 65 percent reduction in lighting energy. It was found that energy efficiency and occu- pant satisfaction could be increased by simply allowing the oc- cupants to control the overhead lighting in their personal space according to their individual needs. Research has shown that personal control is best used when lighting fixtures are dedi- cated to the individuals who will control them, to avoid conflict with neighbors who may have different visual preferences. Currently, the Adura system is being used at two UCB li- braries (Figure 2). The two projects, installed for $28,000, are expected to cut annual electricity use by a combined 170 megawatt-hours (MWh) and will pay for themselves in less than a year. In the Moffitt Library, the system allows the lighting to be scheduled according to the nuances of an aca- demic schedule—allowing different hours for exam periods, holidays, and recess—through a web interface. In the Doe Library, the system turns off the fluorescent lights during the day when daylight is provided by a series of skylights. Previ- ously, the lights were on 24/7 in both facilities. Figure 1: Elements of a wireless lighting-control system N The lighting-control system being developed by Adura Technologies features a set of Controllers and switches that Communicate with One another wirelessly Over a network with multiple redundant paths. Ongoing research will add photosensors and Occupancy sensors to the mix. t- Internal Ethemet LAN Web-based (tº Adura interface |fa gateway s: > 8, *, *, [A]