Wireless Lighting Controls Reach the Tipping Point
One of the key obstacles to deploying intelligent lighting controls systems in existing buildings is the cost of running low-voltage control wiring and the disruption it causes. However, a recent study from Pike Research predicts significant growth in this retrofit market – citing the office, education, and retail sectors specifically.
Wireless lighting controls are the breakthrough technology making standalone lighting controls, as well as networked building energy management systems, practical in many retrofits. A sophisticated wireless mesh network can even provide lighting control where wired systems are impossible. By offering flexibility in positioning and repositioning sensors, wireless systems can maximize energy savings now and save on future remodels.
Intelligent lighting controls basics
Wireless lighting controls send radio-frequency (RF) signals through the air. The most-basic system comprises a sensor (a manual switch, photocell, occupancy sensor, etc.) that sends a command to an actuator, usually a relay or dimmer. Some wireless lighting control systems employ multiple sensors or interface with another network, like a home area network (HAN) or building automation system (BAS). This way wireless lighting controls can exchange signals with keycards and other security sensors, HVAC and water controls, computers, smartphones, plug controls, etc.
Even simple wireless controls devices can communicate over distances of 20 to 100 meters indoors, even through building materials, though communication range will diminish. Powerful systems used outdoors, with a clear line-of-sight, operate over 200 to perhaps 1000 meters. For large buildings and for area and streetlighting, signal range can be extended almost indefinitely by installing signal repeaters or deploying a wireless mesh network.
Wireless lighting controls systems use several different languages, or protocols, to communicate, which fall into two basic categories: proprietary and nonproprietary. A proprietary protocol is used by a single manufacturer and the specifier must choose products from that manufacturer’s line. The advantage is that the one manufacturer warrantees all components and their interoperability and can furnish the complete control system.
Proprietary protocols, used by manufacturers such as Lutron Electronics and WattStopper, are common in standalone, or peer-to-peer, applications: the most popular being an occupancy sensor or photocell with a receiver/relay at the wall switch. “It’s particularly beneficial with retrofits,” according to D.J. Wolbert, product manager for wireless devices at Lutron Electronics “It takes about 15 minutes to install and is coming to a price point that makes it very cost competitive versus wired options, just on a materials basis.”
Lutron Electronics is marketing the PowPak luminaire with integrated wireless lighting controls to save energy in commercial back-of-house areas like stairwells. “That is low-hanging fruit: those systems are generally on 24/7, 365 days a year. With solutions like this you can easily save over 80% of the energy used in that stairwell today.”
ZigBee, Z-Wave, EnOcean, WiFi
Nonproprietary control protocols are not-quite open source and/or licensed for use by several manufacturers. They offer wider arrays of interoperable products and ready integration into BAS networks. “Leviton chose EnOcean for interoperability – 200 companies subscribe to the standard,” said Bob Freshman, Leviton Manufacturing marketing manager for lighting and energy solutions. “Plus EnOcean sensors are self-powered using tiny PV panels or kinetic energy: no batteries needed.”
Campuses, area lighting, roadways, and large buildings like warehouses suggest more-sophisticated nonproprietary protocols that enable mesh networking. For instance, the Zigbee protocol used by Crestron and Sensor Switch. In mesh networks there is no set path for control messages to follow. Like the Internet, signals are communicated via intermediary devices like routers and network gateways. One main advantage is reliability: if a router fails, the signal can still get through via another interconnected device – known as “self-healing.” These highly intelligent systems can also log usage data and report lamp burnouts or other component failures via the web.
On the small scale, HANs also use a wireless mesh architecture, spurred by the utilities’ deployment of wireless smart meters/smart grid technology. Though popular, ZigBee faces several competitors (e.g., Z-Wave, Wi-Fi, and HomePlug) for home area networking.
This year Google entered the fray with its smartphone-based Android@home automation networking standard (based on the 6LowPAN protocol), and may enter smart grid networking, as well. Verizon (Z-Wave), Rogers (Zigbee), and Time Warner Cable (Zigbee) are the first North American telecom providers launching home automation lines.
Tech Note: The Illuminating Engineering Society of North America offers a Technical Memorandum on lighting control protocols, both wired and wireless. To download IES TM-23-11 Lighting Controls Protocols for free, click here.
Written by Lois I. Hutchinson