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ENERGY HARVESTING USING PIEZOELECTRIC MATERIAL

RAHUL SINGH ABHISHEK RITU SINGH BIPIN SINGH

UNDER THE GUIDENCE:MR. AJAY SWAROOP RATURI

Table of Contents

What is the Piezoelectric Effect

Piezoelectric Effect is the ability of certain materials to generate an electric charge in response to applied mechanical stress.Materials which generate an electric potential in response to mechanical stress are considered to be piezoelectric materials.

Piezoelectricity, discovered by Curie brothers in 1880, originated from the Greek word piezenin, meaning, to press.

The original meaning of the word piezoelectric implies Pressure electricity the generation of electric field from applied pressure.Piezoelectricity-HistoryPierre CurieJacques CurieWorking:-

The Process is based on fundamental structure of a crystal lattice. Crystals generally have a charge balance where negative and positive charges precisely nullify each other out along the rigid planes of the crystal lattice. When this charge balance is disrupted by an external force, such as, applying physical stress to a crystal, the energy is transferred by electric charge carriers, creating a surface charge density, which can be collected via electrodes. PIEZOELECTRIC MATERIALS

Bouncing floors in night clubs can be fitted with piezoelectric material so that the energy can be generated using the force produced by dancing people. This power can be used for lightning and operating the sound system.

piezoelectric crystalArrays can be placed underneath sidewalks,stairwells, and pretty much anyother high traffic area to powerstreet lights.

Crystals laid down under keys of mobile unit and keyboard.For every key pressed vibrations are created.These vibrations can be used for charging purposes.

POWER GENERATING BOOTS OR SHOESIdea was researched in US.To power the battlefield equipment by generators embedded in soldier boots.Idea was abandoned due to the discomfort

GYMS AND WORKPLACESVibrations caused from machines in the gym.At workplaces, piezoelectric crystal are laid in the chairs for storing energy.Utilizing the vibrations in the vehicle like clutches, gears etc.

Positioning of piezoelectric circuitAs piezoelectricity is a dynamic process, the material should be positioned in the places were larger and more variable pressure is exerted during walking. Those places are shown in Fig. together with the first prototype. In this prototype single layers of electro-active material were placed on the top of the sole.

As a dynamic process, the material reacts to pressure variations and the generated voltage changes when the pressure on it increases or decreases.

the experimental setup developed for testing the material performance: a shaker applies force to the piezoelectric material at different frequencies and forces.The voltage is recorded on the digital oscilloscope and the energy stored in a battery.

After the placement of the piezoelectric films into the soles , preliminary test are performed by simple jumps. Fig. shows the voltage change when a single jump is applied to a 28 m thick PVDF sample.

This circuit consists of a rectifier bridge based on four Schottky barrier diodes.These diodes have a forward bias voltage drop near 0.33 V, which is an advantage for this application, as it means that for potential values larger than 0.66V (two diodes) it is possible to use the full wave configuration.With p/n junction diodes, this value would be approximately 1.4V.

Many materials, both natural and synthetic, exhibit piezoelectricity: Naturally occurring crystals Berlinite (AlPO4), a rare phosphate mineral that is structurally identical to quartz Sucrose (table sugar) Quartz(SiO2)Rochelle salt Topaz Tourmaline-group minerals

Other natural materials Biological materials exhibiting piezoelectric properties include: Tendon Silk Wood due to piezoelectric texture Enamel Dentin DNA Synthetic crystals Gallium orthophosphate (GaPO4), a quartz analogic crystal Langasite (La3Ga5SiO14), a quartz analogic crystal Polymers Polyvinylidene fluoride (PVDF)

PIEZOELECTRIC MATERIALS CLASSIFICATION

22This technology is tested in California and Israel and have proved successful.

This is an excellent alternative to reach the increasing demands for electricity.

We conclude that it should be implemented in India also to accelerate the development.