Smart device companies wage war on wire

Smart buildings can gain from devices that harvest energy from motion, light and changes in temperature

A group of companies is trying to revolutionise the way buildings operate by removing the need for excess wiring and batteries and by using energy already present in the room.

The motion of a human flicking a switch, for example, creates enough mechanical energy to transmit a wireless signal to the bulb telling it to switch on.

Other examples include light sensors that are powered by the very light they are measuring, and thermostats that can store enough energy to continue working even when the lights go off.

Enocean Alliance is a consortium of companies that use self-powered wireless technology to make products like these, helping buildings to become more efficient. Enocean is a wireless standard, like Zigbee or Bluetooth, but is designed for simple operations and minimal energy usage.

Because most of the devices they seek to replace require very little power, they only make small gains in energy efficiency. But Enocean's chief executive officer Graham Martin says the windfall gains come from the ease and flexibility of renovating buildings. Instead of having to install new wiring systems throughout a building, or hire personnel to replace batteries, organisations can simply stick the switches or monitors on the wall, avoiding any disruption to day-to-day operations.

This makes it easier for organisations to install 'smart' systems that coordinate energy output based on information about light, heat and usage in various rooms. Martin says that more than 100,000 installations have taken place and that the devices can reduce costs by up to 30% as part of a smart system.

There are critical voices: Stan Iordanov, sustainable energy engineer at PRP Architects, says the technology is likely to be more expensive up front than traditional methods, and could be less reliable as well. He also suggests that traditional wiring is more reliable, saying: "Cables connecting switches to things generally don't fail."

However, Martin insists Enocean light switches last longer than the European average for traditional switches.

He also points out that if there was a very wide uptake of such technology then carbon would be saved on the production of millions of miles of copper. "Our biggest competitor is the cable," he said.

(www.guardian.co.uk, 10.08.2010)