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Ppt fly wheel- navin kohli

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Short term backup power through flywheel Storage System

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Ppt fly wheel- navin kohli

  1. 1. Short-term Back- up Power through Flywheel Energy Storage System By Navin kumar Kohli navinkkohli@gmail.com Presentation at JJTU in July 2012
  2. 2. Flywheel • A flywheel, in essence is a mechanical battery - simply a mass rotating about an axis. • Flywheels store energy mechanically in the form of kinetic energy. They take an electrical input to accelerate the rotor up to speed by using the built-in motor, and return the electrical energy by using this same motor as a generator. • They may still prove to serve us as an important component on tomorrow's vehicles and future energy needs.
  3. 3. Flywheel • Provide continuous energy when the energy source is not continuous. • Deliver energy at rates beyond the ability of an energy source. • Control the orientation of a mechanical system.
  4. 4. Introduction • Flywheel energy storage systems store kinetic energy (i.e. energy produced by motion) by constantly spinning a compact rotor in a low- friction environment. • When short-term back-up power is required (i.e. when utility power fluctuates or is lost), the rotor's inertia allows it to continue spinning and the resulting kinetic energy is converted to electricity.
  5. 5. Flywheel Technology • Integrates the function of a motor, flywheel rotor and generator into a single integrated system. • The motor, which uses electric current from the utility grid to provide energy to rotate the flywheel, spins constantly to maintain a ready source of kinetic energy.
  6. 6. Flywheel Technology contd  The generator then converts the kinetic energy of the flywheel into electricity. This integration of functionality reduces the cost and increases product efficiency.  The flywheel rotor spins in a near frictionless environment, created by Active Power's patented magnetic bearing technology.
  7. 7. Principles • The efficiency in the chamber is further enhanced by the creation of a rough vacuum, which reduces drag on the spinning flywheel. • As power is transferred to the load, the flywheel's speed decreases. Additional current is then supplied to the field coil to ensure that the voltage output remains constant throughout discharge. • This enables the flywheel system to provide ride through power during power disturbances.
  8. 8. Flywheel Technology
  9. 9. Stored Energy • Stored energy = sum of kinetic energy of individual mass elements that comprise the flywheel Kinetic Energy = 1/2*I*w2 , where I = moment of inertia (ability of an obeject to resist changes in its rotational velocity) w = rotational velocity (rpm) I = k*M*R2 (M=mass; R=radius); k = inertial constant (depends on shape)
  10. 10. Inertial constants for different shapes • Wheel loaded at rim (bike tire); k = 1 solid disk of uniform thickness; k = 1/2 solid sphere; k = 2/5 spherical shell; k = 2/3 thin rectangular rod; k = ½ • In order to optimize the energy to mass ratio, the flywheel needs to spin at the maximum possible speed. Because kinetic energy only increases linearly with Mass but goes as the square of the rotational speed.
  11. 11. Contd • Rapidly rotating objects are subject to centrifugal forces that can rip them apart. Centrifugal force for a rotating object goes as M*R*w2 . • Thus while dense material can store more energy it is also subject to higher centrifugal force and thus fails at lower rotational speeds than low density material. Therefore the tensile strenghth is more important than the density of the material.
  12. 12. Flywheel Energy Storage System (FES) • In addition to energy density, flywheel energy storage systems (FES) also offer several important advantages over chemical energy storage. The rate at which energy can be exchanged into or out of the battery is limited only by the motor-generator design. • Therefore, it is possible to withdraw large amounts of energy in a far shorter time than with traditional chemical batteries.
  13. 13. Act as Gyroscope • When used in vehicles, flywheels also act as gyroscopes, since their angular momentum is typically of a similar order of magnitude as the forces acting on the moving vehicle. • This property may be detrimental to the vehicle's handling characteristics while turning. On the other hand, this property could be utilized to keep the car balanced so as to keep it from rolling over during sharp turns.
  14. 14. Advantages • Flywheels store energy very efficiently (high turn-around efficiency) and have the potential for very high specific power compared with batteries. • Flywheels have very high output potential and relatively long life. Flywheels are relatively unaffected by ambient temperature extremes.
  15. 15. Disadvantages • Current flywheels have low specific energy. There are safety concerns associated with flywheels due to their high speed rotor and the possibility of it breaking loose & releasing all of it's energy in an uncontrolled manner. • Flywheels are a less mature technology than chemical batteries, and the current cost is too high to make them competitive in the market.
  16. 16. Conclusion • Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage systems for a variety of applications, including automobiles, economical rural electrification systems, and stand-alone, remote power units commonly used in the telecommunications industry. • Recent advances in the mechanical properties of composites has rekindled interest in using the inertia of a spinning wheel to store energy.
  17. 17. REFERENCES • Processes and Materials of Manufacture by R.A. LINDBERG • www.edufive.com/seminartopics.html • www.pcmag.com/encyclopedia • www.me.sc.edu • http://newtechpapers.com/MEpapers2.html
  18. 18. Thank you Navin Kumar Kohli navinkkohli@gmail.com

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