One of the beloved clichés in conceptual green design is to magically embed energy generation capacity into really mundane actions. Design students like to think that jumpy urban warrior energy - from running or skateboarding - can be harnessed in order to power little devices cleverly strapped to one's person. It's a seductive idea, and piezoelectricity is occasionally cited as a way of pulling it off. It's even been prototyped: while he was working on wearable computing at MIT, Thad Starner looked into making shoes with piezoelectrics embedded in the soles, so that each step would generate a little jolt of electricity.
Roughly speaking, piezoelectrics generate a voltage by pressing or deforming very small crystals. But much as we'd like to line our floors and socks with the stuff, it in fact doesn't add up to enough energy to power anything of substance. One of the many things that piezoelectrics can do, however, is generate enough energy to send a brief wireless RF signal. This is exactly the concept behind EnOcean's very cool batteryless technology: in essence, EnOcean captures the energy generated by your finger as it presses a switch, and uses it to turn a light on or off. This means that no longer do we need to build wires into the walls at all, and well-established technology is used to do something totally banal in a completely new way. The result is real dematerialization, the most compelling fact being that the technology's greenness didn't end up being the energy generated, but the materials (and consequent energy) no longer needed to run the system.
Even more interesting is the way that EnOcean enables architectural flexibility. The material rigidity of buildings makes them difficult to modify, and flexibility is more important than we think: a huge percentage of our building waste comes from the renovations and changes that we make as our needs change.
i used to play around with sound-activated relays as a kid. with the technology available now, i wonder if it would be possible to:
1. say "red bulb!"
2. the "switch" uses the energy of the sound you have just emanated (and understands which device you refer to by analysing the sound pattern) to send a small radio burst "only" the red bulb, which comes on.
3. no need to go and press any switch. I mean, no wires and...NO SWITCHES either!
I've never heard of piezoelectrics. Thanks for an interesting post! I do, however, have a an issue with the application for this technology.
If one were to use these switches, one would still have to wire the light fixtures and power the receivers for the RF signal. While integrating these switches may reduce the total amount of actual wire on a per job basis, thereby reducing the materials (and consequent energy), I wonder how much extra energy would be needed to keep the receivers in an "always-on" state. That's one of the nice things about lights: when you turn them off they don't use energy :^)
Is there a design in the works for the fixtures that would work with this type of switch?
I worked for a while in an old warehouse that had been converted into offices. They had to run electric wires over the brick walls.
Designers and architects would have probably preferred this alternative, and it could cost a lot less: fewer materials, and no need to hire people to install them. Moving lights would be easier too.
Intellectually drafted article. seems to grab attention at once.The writer has a good knowledge of the subject and makes reading interesting.
I spent some time in the u.s. navy. One of the oldest and most relaible techonlogies was what is called a sound powered phone. These phones work on the concept of piezoelectricity, in that the sound waves generated by your voice speaking into the handset cause a crytal to vibrate, outputting a small electrical signal which matches your voice waves exactly. This signal travels down a set of wires to a corrosponding handset at at an amazingly far interval and causes the corresponding pizeo crytal in the receiving handset to generate sound waves in the exact opposite way. And vice versa. No outside electricity is required. The tech is at least 50 years old, and perhaps older. They are used mainly in damage control activities, but work in any manner. The tech is out there and working. im sure it could be modded to do all sorts of wonderful things. The problem is that the handssets themselves are large and unweildy,although the possibility of redesign is out there.
I foresee the toilet seats made of this material.
Let's use our buttocks to move the technical progress forward!
Dawn, this is interesting. Of course lights themselves would still need to be wired, but this could make reconfiguring large spaces easier. When offices, warehouses, etc. change their layout, the lights often remain in place, but the switching needs to change. It's appalling to learn what goes into making wire, especially the insulation. If this reduces the use of cable, and encourages adaptive reuse of buildings, that would be great.
I thought you might be intrested in another human powered device:
The "Suspended-load Backpack" converts mechanical energy from walking into electricity - up to 7.4 Watts - more than enough energy to power portable electronic devices for soldiers, field researchers or disaster relief-workers.
In addition to the push button energy harvesters that Dawn wrote about, EnOcean also converts process energy from indoor ambient light into electrical energy to power a wide variety of sensors. This enables one to sense the environment and assists in the delivery of resources or utilities when and where needed. Example - moisture sensors in the lawn (self contained, powered by light) instruct the irrigation system when and how long to water rather than simply by preprogrammed timers. Brightness sensors in a room dim a light to consume less electricity and generate less heat. Outdoor temperature sensors detect freezing pipes and shut off valves. You can see additional ideas at www.enocean.com
There is a US company that has had battery-less wireless switches on the market for more than a year. You can see them on www.LightningSwitch.com . These guys use a piezoelectric from NASA. You can buy a set for about $50. Some friends of mine have them since last Christmas and they really are quite impressive.
If anybody is interested in the enocean products; TDC (part of the Abacus Group) have the UK franchise for all enocean transmitters and receivers. Please see our website www.tdc.co.uk/enocean or call on +44 (0)1256 332800 for further information