Electromagnetic induction in energy harvesting applications
Sept 26, 2013
So....you take a scientific principle that is so well understood it can be considered mundane. You then have two options with it:
a. You do something mundane with it, as derivative as anyone would expect...
b. You do something unexpected, something that turns possibilities into a tangible reality.
Take electromagnetic induction for instance. I learnt about it at elementary school and most likely, so did you. You would move a permanent magnet inside a copper coil and the changing magnetic field would induce a voltage in the coil; connect a lamp at the end of the coil and you'd see it light up when the magnet moved.
Basic demonstration of electromagnetic induction
Since 1830, when Michael Faraday and Joseph Henry independently discovered electromagnetic induction, the most common application has been the bicycle dynamo (or alternator, more correctly, as these devices generate alternating current). Although inefficient, this has been a reliable, easy to manufacture device that has kept bicycle lights going in the night for decades, with incremental innovations realised as, in reality, who really cared enough to fund the making of a better bicycle dynamo?
A bottle dynamo, from Bosch
According to recent IDTechEx research on the topic of electrodynamic energy harvesting, almost 20 million devices will be sold in 2024 that will not be bicycle generators. Instead, they will be wireless switches, energy harvesters enabling wireless sensing in transport, industrial and building automation, devices that put the common alternator to work in market segments that there was previously no use for it. Source: Energy Harvesting and Storage for Electronic Devices 2014-2024: Forecasts, Technologies, Players.
Examples of applications: Induction in energy harvesting
The Seiko Kinetic watches were a good example of using the principle of generating energy from movement in a small scale, with a storage device such as a rechargeable battery or a capacitor, used side by side with the generator, in order to store electrical energy for later use.
A very interesting prototype, shaped like an AA battery was demonstrated back in 2010 by Brother Inc. of Japan, enabling the replacement of batteries in devices such as remote controls, without the need for changing the battery hubs in remotes.
Brother's AA shaped energy harvester
The best known electrodynamic harvester is the device of EnOcean GmbH that is usually installed into wireless light switches in building infrastructure. The device harvests energy when the switch is pressed and allows a plug-and-play switch design with no need for rewiring, making retrofitting of buildings a very simple task.
The EnOcean ECO 200 energy converter for motion energy harvesting
In industrial automation applications, where more robust designs are required, Perpetuum has made available its vibration harvester, most recently seen in application in the railway sector. In June 2013, Perpetuum won a contract to supply Southeastern Railways with energy harvester powered wireless sensors to monitor the wear of wheel bearings for 148 Trains. The generators produce 10mW - 15mW of continuous power for the duration of the journey while sensor systems collect vibration data which is transmitted wirelessly to a database where software algorithms look for the signatures of bearing and wheel wear.
Perpetuum wireless sensor powered by vibration harvesting, for monitoring bearing and wheelwear in trains
Market changes from 2015 onwards
As can be seen from the following graph, taken from the latest IDTechEx report on energy harvesting, dynamos will remain the dominant market segment for induction based harvesters in the short term, but in later years (from 2016 onwards) we will witness a significant change in the balance of the markets, with industrial and building applications growing faster and claiming larger market shares.
Market value for electrodynamic energy harvesters, 2013-2015
To hear presentations from Bosch and Perpetuum, as well as many others movers and shakers in the energy harvesting scene, attend the forthcoming IDTechEx conference, Energy Harvesting & Storage taking place on November 20-21 at the Santa Clara Convention Center - www.EnergyHarvestingUSA.com .
For more information, contact Corinne Jennings at c.jennings@IDTechEx.com +44 (0)1223 813703.