Energy Harvesting ‘Piezo-tree’ Concept

Energy Harvesting ‘Piezo-tree’ Concept.

As the leaves move in the wind energy is generated, this is then converted into electric energy. The flapping motion of the leaves is attributed to instability of the aero-elastic system. The “Piezo-tree” has been made using flexible piezoelectric material Polyvinylidene Fluoride (PVDF).

 

 The device is able to convert the energy in wind into electric power whilst remaining light, low-cost, and easily scaled.

 

In the prototype, the flexible plate and film are driven to oscillate just as a flag or leaf might flap in the wind. The flapping motion is attributed to instability of the aero-elastic system. When creating the piezo-tree, researches used the flexible piezoelectric material Polyvinylidene Fluoride (PVDF) as the basic component, as it could withstand unpredictable wind strength. The basic design is to clamp one edge of PVDF element to a cylinder bluff body and leave the other edge free. When the wind crosses this bluff body, it will lead to a vortex shedding and the periodic pressure difference will drive the piezo-leaf to bend in the downstream of the air wake, synchronously. AC signal is collected from the flapping piezo-leaf, which is working on a periodic bending model, and the electrical energy is stored in a capacitor after rectifying it with a full-wave bridge.

 

 

 

 

However, because of the weak piezoelectric strain coefficient of PVDF, the preliminary Piezo-Leaf Generator's power level was just about 100 pW, unable to drive even a common LED. Then, researchers tried to attach a piece of plastic film to the end of the leaf along the direction of air flow, which showed about 100 times increase of power in the same condition. A series of experiments were conducted using attachments of various shape, area, density and flexibility of plastic and polymer film producing different results in the level of power.

 

 Sure the artificial trees are inspired by real trees, and SolarBotanic's Nanoleaves convert sunlight into energy just like tree leaves, but the energy user is not the leaf or the tree itself. To convert sunlight into energy, the Nanoleaves contain photothermovoltaic cells, that convert the whole spectrum of light, even light we can't see, like radiation, into electricity,

Nano piezo electric generators in the twigs and branches, simultaneously convert wind into millions of Pico watts. The more the wind blows, the more the leaves move (flap frequency), the more the Nano piezo generators are stimulated to make more energy, and then you have trillions of Pico watts!

Another fascinating SolarBotanic technology is used to separate the carbon dioxide from other elements in the air. It involves biomimicry of the human lung. The device at the bottom of the tree below has a fixed carrier in the membrane that enables only the "good" air molecules to convert to energy.

Right now, two main kinds of trees are drawn up. One, the broad leaf trees, can provide between 33500 kWh and 7000kWh per year, in addition to providing shade, breeze, and beautty. Another biomimicry design, the Octopus root system, secures the broad leaf trees in the ground.
SolarBotanic's ever green trees provide between 2500kWh and 7000kWh per year. These trees are good for mountainous regions and hill sides, as they provide good sound absorbers.
SolarBotanics has also planned a variety of smaller artificial shrubs for your smaller electrical needs, like household appliances. SolarBotanic has Nanoleaf roof and wall carpets that can be easily installed with various leaf designs.
As you can see, SolarBotanic trees and leaves have many functions besides providing energy.

 

Additionally, design optimization studies found that a particular vertical stalk, horizontal leaf arrangement could increase power output by an order of magnitude. This is a massive, ten-fold improvement over current leaf-stalk arrangements. As a simple, robust, and easily scaled device, the "piezo-tree" would serve as an effective and unique power generator in a variety of environments. For practical application the researchers hope to build plant-like devices with hundreds or thousands of piezo-leaves.

The movement of leaves is responsible for generating energy. They convert wind energy into electrical energy. The flapping motion of the leaves causes the instability of the aero-elastic system. The main constituent of the “Piezo-tree” is of Polyvinylidene Fluoride (PVDF) which is a flexible piezoelectric material.

 

 

 

 

 The Piezo Tree

 

 

The field of piezo technology is extensive and has many branches. The "piezo tree" already bears numerous fruits, but continues to develop new blossoms. Piezo elements serve, for instance, as filters for electromagnetic waves (surface acoustic wave filters, filter ceramics).

They convert electromagnetic signals into sound (loudspeakers, buzzers) and vice versa (telephone microphones, knock sensors), and they transform mechanical pressure into electrical signals (batteryless wireless technology, piezo igniter). Some elements serve as ultrasonic sensors, while others create ultrasound in echo sounders, in medical diagnostics, in flow-rate meters or for fluid atomization. Piezo actuators are a new, fast-growing branch that enables applications ranging from piezo injector valves right up to powerful piezo motors. Such motors are already available, for instance, from Elliptec Resonant Actuator AG—a start-up that emerged from Siemens—for the toy and consumer market. Multilayer actuators are also suitable for a completely new type of power window for automobiles that contains integrated sensor technology

Siemens was also the leader in developing piezo transducers for ultrasound diagnostics in healthcare and for the first inkjet printers, in which a jet of ink was ejected from thin piezo tubes. Corporate Research provided the momentum for many of these innovations. For example, Andreas Kappel, who had previously worked on the development of piezo inkjet printers and has registered numerous patents since the 1990s, also gave piezo injectors a very big push. He developed hydraulic translators that could increase the stroke of a piezo actuator and compensate for changes of length due to temperature. "The inkjet printer tubes are fundamentally nothing other than mini injection nozzles," says Kappel, who received the coveted Siemens accolade "Inventor of the Year" in 2002.

Another coup was pulled off by the Piezo Laboratory, in the form of the surface acoustic wave (SAW) filter made of lithium niobate, which replaced electromagnetic filters in Grundig television sets in 1977 and markedly improved picture and sound quality. Unlike the large, costly 100 kHz filters for telecommunications technology, SAWs were small and inexpensive. Although they quickly became popular, they didn’t make real money until the mobile phone boom took off. "Mobile phones would be unthinkable without SAWs," says Guntersdorfer.

In 1989, the piezo team scored a huge success in automotive engineering with the knock sensor, an electronic ear for the engine that optimizes fuel efficiency. "There are now 40 million engines equipped with Siemens knock sensors worldwide," reports physicist Randolf Mock. Mock considerably advanced the development of the sensor by means of computerized simulations.
Batteryless radio technology is a new development from the "piezo works." By simply pressing a light switch, a piezoelectric energy transducer is able to generate enough energy to transmit a radio signal to the light source. In 2001, Siemens employees founded start-up EnOcean in order to market the invention. In the meantime, other ideas have been implemented, including a tire sensor that works without batteries.