IJEETC. InternationalJournalof. ElectricalandElectronicEngineering& Telecommunications.

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1 IJEETC InternationalJournalof ElectricalandElectronicEngineering& Telecommunications

2 Int. J. Elec&Electr.Eng&Telecoms Himanshu Gaurav et al., 2015 Research Paper ISSN Special Issue, Vol. 1, No. 2, July 2015 National Conference on Emerging Trends in Electronics & Communication (ETEC-2015) 2015 IJEETC. All Rights Reserved ENERGY HARVESING THROUGH SMART GYM Himanshu Gaurav 1 *, Kavindra Singh Nikhurpa 1, Dhruva Chaudhary 1 and Wasim Feroz 1 *Corresponding Author: Himanshu Gaurav, himanshu.gaurav1994@gmail.com This paper proposes a new concept of energy harvesting through smart gym. With the advent of new technology and gadgets, power requirement is increasing day by day. Thus, new energy harvesting methods are high in demand. The advances have allowed numerous ways for power harvesting systems in practical applications in order to meet the power demand. The use of piezoelectric crystal is to generate electric output from surrounding vibrations. Piezoelectric materials have a crystalline structure that they can convert mechanical energy into electrical charge and is vice-versa. These materials have the ability to absorb mechanical energy from their surroundings, usually ambient vibration, and transform it into electrical energy that can be used to power other devices. We can also harvest energy by converting kinetic energy into electrical energy. This can be achieved by using electric generator. Another material that we can utilize to generate electrical energy is electro active polymer. Electroactive polymers produce an electrical current from a change in shape or size as they are stretched or relaxed and displays higher performance in terms of energy density and efficiency than traditional transducer materials and have a lower production cost. In this paper, we discuss about many researches that has been performed in the area of power harvesting. Keywords: Piezoelectric material, Electric generator, Electro active polymer, Voltage booster, Battery INTRODUCTION Man has needed and used energy at an increasing rate for his purpose. Due to this a lot of energy resources have been exhausted and wasted. The utilization of waste energy of foot power with human locomotion is very much relevant for highly populated countries where the roads, railway stations, bus stands, temples, etc. The human bio-energy being wasted if it can be made possible for utilization it will be very useful energy sources. Walking is the most common activity in day to day life. While walking, the person loses energy to the surface in the form of vibration. This energy can be tapped and converted to electrical form. Piezoelectric crystals convert the mechanical 1 Faculty of Engineering, University Malaysia Sarawak (UNIMAS), Kota Samarahan 94300, Sarawak, Malaysia. 37

3 vibrations into electrical energy. When piezoelectric crystals are subjected to vibration they generate avery small voltage, commonly known as piezoelectricity. It has a crystalline structure that converts an applied vibration into an electrical energy. The piezoelectric effect exists in two properties: The first is the direct piezoelectric effect that describes the material s ability to transform mechanical strain into electrical charge. The second form is the converse effect, which is the ability to convert an applied electrical potential into mechanical strain energy. These properties allow the material to function as a power harvesting medium. The produced output voltage is in the form of AC. Then it can be converted to DC by passing it through Rectifier circuit. For harvesting kinetic energy from various gym equipment such as treadmill and bicycle machine, we will be using electric generators Figure 1: Energy Harvesting Through SMART GYM that will convert kinetic energy into electrical energy. An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output. A generator does not actually create electrical energy. It uses the mechanical energy supplied to it to force the movement of electric charges present in the wire of its windings through an external electric circuit. This flow of electric charges constitutes the output electric current supplied by the generator. There are two types of generators, one is ac generator and other is dc generator. Whatever may be the types of generators, it always converts mechanical power to electrical power. An ac generator produces alternating power. A dc generator produces direct power. Both of these generators produce electrical power, based on same fundamental principle of Faraday s law of electromagnetic induction. According to this law, when a conductor moves in a magnetic field it cuts magnetic lines force, due to which an emf is induced in the conductor. The magnitude of this induced emf depends upon the rate of change of flux (magnetic line force) linkage with the conductor. This emf will cause a current to flow if the conductor circuit is closed. We can also extract energy from gym equipment like leg press or bench press more efficiently by applying Electroactive Polymers which produce an electrical current from a change in shape or size. Other materials, such as piezoelectric ceramics which produce electricity resulting from mechanical pressure have different limitations. Not only do they often contain undesirable lead compounds. They are also relatively stiff and require a heavy and rigid connecting structure linking them to energy sources. 38

4 After conversion of different energies into electrical energy, we will require some kind of storage device to store electrical charge for further use. For this purpose, we will be using Nickel Cadmium Battery which is more efficient than other storage devices available. The nickel cadmium battery (NiCd battery or NiCad battery) is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes. The abbreviation Ni-Cd is derived from the chemical symbols of nickel (Ni) and cadmium (Cd): the abbreviation NiCad is a registered trademark of SAFT Corporation, although this brand name is commonly used to describe all Ni Cd batteries. Ni-Cd batteries are made in a wide range of sizes and capacities, from portable sealed types interchangeable with carbon-zinc dry cells, to large ventilated cells used for standby power and motivepower. Compared with other types of rechargeable cells they offer good cycle life and capacity, good performance at low temperatures, and work well at high discharge rates (using the cell capacity in one hour or less).however, the materials are more costly than types such as the lead acid battery, and the cells have higher self-discharge rates than some other types. Sealed Ni-Cd batteries require no maintenance. The superior capacity of the Nickel-metal hydride batteries, and more recently their lower cost, has largely supplanted their use. Further, the environmental impact of the disposal of the heavy metal cadmium has contributed considerably to the reduction in their use. Within the European Union, they can now only be supplied for replacement purposes although they can be supplied for certain specified types of new equipment such as medical devices. OUR APPROACH In this paper, we are going to discuss about numerous methods to convert a traditional gym into Smart Gym which can exploit the great potential of human bio-energy. Piezoelectric material [1-7] can convert vibration from footsteps into electrical energy. In order to achieve this, piezoelectric materials are placed under special flooring of tiles which are made up of rubber so as when the movement is felt by the material they can generate the electricity. When a person steps on them, then by piezoelectric effect small charge is built up. So the energy generated by one human would be too less but if the number of steps on these kinds of tiles increases then energy produced by it would increase too. When a person steps on such tiles piezoelectric crystal under the tiles would experience some mechanical stress which makes electric charge to build up on crystal s surface which can be collected by use of electrodes. The produced electrical energy from the piezoelectric crystal is very low in the order of 2-3volts and is in ac form. It can be converted into dc by using rectifier and is initially stored in a 2v rechargeable battery through a charge controller,since it is not possible to charge a 12V battery through crystal output. In order to increase the voltage, the boost converter circuit Figure 2: Conversion of Vibration Energy into Electric Energy 39

5 is used. The use of boost converter is to increase the level of voltage ranges about 12V and is stored in a 12V battery. We can utilize electric generator [8-11] in gym machines (like treadmill, bicycle) to convert human power (i.e., mechanical energy) into electrical energy. Electric generator is attached to the pedal (in case of bicycle machine) or other moving parts (in case of other gym machines). When the human power is applied, the respective conductor rotates and cuts the magnetic flux, dynamically induced emf is produced in it according to Faraday s law of electromagnetic induction. This emf causes a current to flow if the conductor circuit is closed. This output is then fed to the rectifier (in case of ac generator) and then it is amplified using voltage booster and finally stored in battery. An average healthy human can produce approximately 75 Watts (0.1 horsepower) for Figure 3: Special Flooring of Tiles Using Piezoelectric Material Figure 4: Conversion of Kinetic Energy into Electric Energy a full eight hour period, while a first class athlete can produce approximately 298 Watts (0.4 horsepower) for a similar period. Therefore, the power generated by this method is efficient and can be further used for general purposes. We can use Electroactive Polymer [12-13] in stretching gym equipment (such as leg press, bench press) to generate electrical energy. One of the main reason of applying Electroactive polymers in such equipment is their property to produce an electrical current from a change in shape or size as they are stretched or relaxed and displays higher performance in terms of energy density and efficiency than traditional transducer materials and have a lower production cost. The most popular type of electroactive polymer is dielectric elastomers. These are thin sheets of elastic insulators coated with Figure 5: Dielectric Elastomer 40

6 stretchy electrodes. They generate energy by mechanically separating the electric charge and thereby increasing the electrical energy as the stretch condition of the elastomer is relaxed and the thickness of the sheet increases. This makes them, a kind of stretchable capacitors. It utilizes compression and expansion to harvest power from human motion without adding any physical burden. It uses transducer consisting of various stacked layers of dielectric elastomer films. The generator works by using a fluid (or gel) coupling to transfer the compression or expansion to stretching of the elastomer films, thus generating electricity. This method can produce an electrical output of approximately 0.8 joules (J) perexpansion/compression, equivalent to a power of 1 Watt. The output obtained from dielectric elastomer is amplified using voltage booster and then stored in battery. CONCLUSION The various methods of generating electricity discussed in this paper are eco-friendly and cause no pollution. They are easy to install and utilizes the human bio-energy in the most efficient way. These energy conversion methods convert a traditional gym into a Smart Gym. Despite of limitation that its installation cost is higher, the concept of Smart Gym has great scope in developing countries where youths are becoming more fitness conscious. Government can also ensure maximum energy harvesting by encouraging investors and providing the gym facility to a large number of people at a reasonable price. REFERENCES 1. Anil Kumar (2011), Electrical Power Generation Using Piezoelectric Crystal, International Journal of Scientific & Engineering Research, Vol. 2, No. 5, ISSN: Bar-Cohen Y (Ed.) (1999), Proceedings of the SPIE s Electroactive Polymer Actuators and Devices Conf., 6 th Smart Structures and Materials Symposium, Vol. 3669, pp , ISBN: Bar-Cohen Y (Ed.) (2000b), Proceedings of the SPIE s Electroactive Polymer Actuators and Devices Conf., 7 th Smart Structures and Materials Symposium, Vol. 3987, pp , ISBN: Collins L (2006), Harvesting for the World: Energy Harvesting Techniques, IEEE Power Engineer, Vol. 20, pp Crawley E F and de Luis J (1986), Use of Piezoelectric Actuators as Elements of Intelligent Structures, Present as Paper at the AIAA/ASME/ASCE/AHS Active Structures, Structural Dynamics and Materials Conference, May 19-21, San Antonio, TX. 6. Jaber Abu-Qahonq and Issa Batarseh (2000), Generalised Analysis of Soft- Switching DC-DC Convertors, in IEEE International Symposium on Circuits and Systems, May 28-31, Geneva, Switzerland. 7. Lakic (1989), Inflatable Boot Liner with Electrical Generator and Heater, Patent No Mohan Ned, Undeland, Tore M Robbins and William P (2003), Power Electronics 41

7 - Hoboken, John Wiley & Sons, Inc., ISBN: Shu Y C and Lien I C (2006), Efficiency of Energy Conversion for a Piezoelectric Power Harvesting System, Institute of Physics Publishing Journal of Micromechanics and Micro Engineering, J. Micromech. Microeng., Vol. 16, pp Thomson W T (1988),Theory of Vibration with Applications, Chapter 9, Prentice- Hall, Englewood Cliffs, NJ. 11. Ugural A C (1999),Stresses in Plates and Shells, McGraw-Hill, New York. 12. Umeda M, Nakamura K and Ueha S (1997), Energy Storage Characteristics of a Piezogenerator Using Impact Vibration, Japan Journal of Applied Physics, Vol. 36, Part 1, No. 5b, pp Vivek Kumar et al., Upgraded Ultrasonic Animal Repellent Device, Proceeding of National Conference on Striving & Thriving Towards Diffusion of Sudden Driven Research in Science and Technology for Inspired Learning, p. 268, ISBN: Wilson R E and Lissaman P B S (1974), Applied Aerodynamics of Wind Power Machines, NTIS PB , Oregon State University. 15. Zelenka J (1986), Piezoelectric Resonators and their Applications, Elsevier, Amsterdam. 42

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