Energy harvesting devices converting ambient energy into electrical energy have attracted much interest in both the military and commercial sectors. Some systems convert motion, such as that of ocean waves, into electricity to be used by oceanographic monitoring sensors for autonomous operation. Future applications may include high power output devices (or arrays of such devices) deployed at remote locations to serve as reliable power stations for large systems. Another application is in wearable electronics, where energy harvesting devices can power or recharge cellphones, mobile computers, radio communication equipment, etc. All of these devices must be sufficiently robust to endure long-term exposure to hostile environments and have a broad range of dynamic sensitivity to exploit the entire spectrum of wave motions. There are different ways to generate kinetic energy like: Hydraulics, piezoelectric, etc. However, we will focus more on piezoelectricity as it is the process that is used in kinetic tiles.
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Piezoelectricity is the electric charge that accumulates in certain solid materials (such as crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical stress. The word piezoelectricity means electricity resulting from pressure [18].
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Piezoelectricity is a form of electricity that is mainly produced due to pressure. When pressure or stress is put on certain materials, an electric charge is produced and is stored. This is the basic principal behind piezoelectricity. In order to use them in real life applications piezoelectric sensors are made that produce a voltage change when there is a change in either pressure, temperature or strain. These sensors help in determining the measurement of the charge produced. Piezoelectricity is the basic science used in kinetic tiles. When pressure is put on the tiles by the human step, they produce electricity which is then stored and can be used to provide electricity [11].
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The piezoelectric effect is understood as the linear electromechanical interaction between the mechanical and the electrical state in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process in that materials exhibiting the direct piezoelectric effect (the internal generation of electrical charge resulting from an applied mechanical force) also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field) [13].
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How is it Generated?
Piezoelectricity
What Do The Experts Say?
Our expert is Dr. Oomman Varghese, who is an associate professor at the University of Houston. He specializes in nano structured materials, excitonic solar cells, solar fuel generation and environmental sensing. According to Dr. Varghese, piezoelectrics is a very broad field on electrics. He states that the kinetic tiles project is based on the concept of piezoelectricity. He also said that piezoelectrics is an old source of energy but it is a relatively untapped source of electricity. According to Dr. Varghese, the advantage of this technology is that it is highly resourceful with a very small carbon footprint. He believes that its maintenance costs and the durability of the tiles might outweigh the initial investment and the savings. He also states that piezoelectricity was mostly used as a detection scale rather than a form of energy and electricity. Dr. Varghese highly encourages the research on piezoelectricity as a source of electricity, but according to him piezoelectricity usually produces a low current supply with a very high voltage which is a problem in electricity generation.