Wireless Energy Harvesting Technology Can Cut Fuel Bills

Energy harvesting is a technology that uses the existing environment as a source for energy rather than drawing on mains electricity or batteries. But a growing group of companies are combining this with wireless technology to help building management systems reduce energy consumption even further.

The group is known as the Enocean Alliance and its 150 members have been installing this technology for a couple of years now and it is already in more than 150,000 buildings. Results from schools and hotels have seen energy bills cut by twenty to thirty per cent and a recent installation at student accommodation in the UK saw savings of forty per cent.

Energy Harvesting Technologies

Alliance members basically use three types of energy harvesting. The first is one that can be used in domestic building as well as offices for saving on cabling costs for lighting or remote electrical switches. Rather than having wires sending the signal from, say, a light switch to the light itself, this is done by a wireless signal. The act of flicking the switch generates enough electricity to send the wireless signal.

The second two methods of energy harvesting are more suitable for sensors for measuring, say, room temperature or humidity, or even detecting whether a room is occupied or not. One of them uses the normal room lighting to power a solar cell and can store enough electricity when the lights are on to work for days in the dark. The other uses temperature differences to generate the electricity. To work, the temperature between one face and the other must be more than four degrees celcius, which can be achieved by say attaching it to a radiator.

The beauty of these is that they can be retrofitted quickly in hotel rooms, for example, with no wiring involved. In fact, some recent installations have been done during the normal cleaning of a room between occupants.

Energy Savings

This green energy technology has already produced some impressive results. “Hotels are a big market,” Graham Martin, chairman of the Enocean Alliance, told Suite 101. “There is a lot of wasted energy in hotels. You can easily save twenty per cent in heating and cooling costs. And you can retrofit it without closing the building.”

At the University of Kent at Canterbury in the UK, the technology was fitted to the windows in student bedrooms and just turned the heating off whenever the window was opened. This alone cut the energy bill for the halls of residence by forty per cent.

For new domestic buildings, Martin reckons that this technology can save 200 to 300 metres of cable in a normal sized house.

Future for Green Energy

The progress of wireless energy harvesting technology is still progressing and Barclays Bank is in the process of installing it at 500 locations around the UK. The Enocean Alliance is also trying to get the technology ratified as a formal standard by the IEC though Martin said that the number of installations already made it a de facto standard.

(Source energy-conservation.suite101.com, 21.05.2010)