Piezoelectricity and You.

Sustainability got sexier last week at the opening of Surya in London. The Club4Climate project is London’s first taste of eco-friendly clubbing, making clubbers happy in the knowledge that their organic beverage-induced booty shaking can generate 60% of the energy needed to run the club. The venue’s most exciting innovation is the piezoelectric dancefloor, which uses quartz crystals and ceramics to turn clubbers’ movement into electricity!

Previously seen in the Sustainable Dance Club in Rotterdam, this is Britain’s first exposure to such technology. The rest of the power needed will come from a wind turbine and solar energy system, with any surplus used to power private homes in the area. The club will also be installing the latest air flush, waterless urinals, low flush toilets and automatic taps to ensure maximum water saving plus less greedy air conditioning units.

The project is clearly trying to affect behavior on a much wider scale, too, requiring patrons to sign a 10-point manifesto on entry, giving free entry to anyone who can prove that they walked or cycled to the venue, and encouraging as many other clubs as possible to adopt his philosophy.

Property developer Andrew Charalambous is behind Club4Climate, appearing in character as ‘Dr Earth‘ to be more down with the kids. He says the club aims to ’stop preaching to people and use an inclusive philosophy to create the revolution [needed] to combat climate change.’ A Club4Climate island is also planned for 2010, although how clubbers will transport themselves to the island hasn’t been mentioned.

In another shining example of using what you have  for power generation, a Netherlands train station is using a revolving door to produce electricity. The Natuurcafe La Port in the train station expects the coming and going of patrons to provide 4,600 kWh a year. So, while the coffee powers the customers, the customers are powering the coffee shop.

The door uses a generator that harvests the kinetic energy produced when the door spins and a supercapacitor to store the energy. The energy is used to power the cafe's LED lights. When the lights use up the stored energy from the door, the station's main energy supply takes over. For the curious, the station has a display that shows the amount of energy generated as customers walk in and out.

While 4,600 kWh is a small amount compared to a train station's total energy needs, it's great to see a large building harvesting renewable energy from as many sources as possible. These types of kinetic energy generators could go a long way if they're consistently implemented in both new buildings and renovation projects.

Piezoelectricity is the ability of some materials (notably crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) to generate an electric field or electric potential[1]  in response to applied mechanical strain. The effect is closely related to a change of polarization density within the material's volume. If the material is not short-circuited, the applied stress/strain induces a voltage across the material. However, if the circuit is closed the energy will be quickly released. So in order to run an electric load (such as a light bulb) on a piezoelectric device, the applied mechanical stress must oscillate back and forth. For example, if you had such a device in your shoes you could charge your cell phone while walking but not while standing. The word is derived from the Greek piezo or piezein (πιέζειν), which means to squeeze or press.

The piezoelectric effect is reversible in that materials exhibiting the direct piezoelectric effect (the production of an electric potential when stress is applied) also exhibit the reverse piezoelectric effect (the production of stress and/or strain when an electric field is applied). For example, lead zirconate titanate crystals will exhibit a maximum shape change of about 0.1% of the original dimension.

The effect finds useful applications such as the production and detection of sound, generation of high voltages, electronic frequency generation, microbalances, and ultra fine focusing of optical assemblies. It is also the basis of a number of scientific instrumental techniques with atomic resolution, the scanning probe microscopies such as STM, AFM, MTA, SNOM, etc., and everyday uses such as acting as the ignition source for cigarette lighters and push-start propane barbecues.