IB Wind and Wave Power

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IB Wind and Wave Power

• Mark Kapron, Luc LaLonde, Scott Johnstun

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Wind Power

• A wind generator is commonly know as a wind
  turbine.
• Unlike a fan, producing wind with the help of
  electricity, the wind turbines produce
  electricity with the help of wind.

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How Do They Work?

• A gust of wind blows through the blades of the
  turbine causing it to rotate, which creates large
  amounts of kinetic energy.
• This kinetic energy turns a shaft, which in turn
  turns the generator and creates electrical
  energy.

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(No Transcript)
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Power Generated by Wind

• Albert Betz was a German physicist who in 1919
  concluded that no wind turbine can convert more
  than 16/27 (59.3) of the kinetic energy of the
  wind into mechanical energy turning a rotor. To
  this day this is known as the Betz Limit or Betz'
  Law. This limit has nothing to do with
  inefficiencies in the generator, but in the very
  nature of wind turbines themselves.

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Proof?
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But seriously

• You cant convert all of the kinetic energy in
  the area of the circle that the blades cover
  because some of the wind will pass through
  without interacting with the system.

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Problem Solving Wind

• Wind power 1/2 x Swept Area x Air Density x
  Velocity3
• The world's largest wind turbine generator has a
  rotor blade diameter of 126 meters and a rotor
  sweep area of 12470 m2. The turbines are also
  moving at a speed of 14m/s. Find the power
  produced by the turbines.
• The air is situated at sea level, so it equals
  1.23kg/m3 Wind Power 0.5 x 12,470 m2 x 1.23
  kg/m3 x (143) m3/s3
• Wind power 21,000,000 Watts or 21 MW.

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Not Drawn to Scale
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Part 2 Wave Power

• Clean energy produced by using the power of
  oceanic waves. Around the world, day and night,
  waves produce a tremendous amount of untapped
  energy. Methods of harnessing this energy are
  being discovered rapidly.

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Various Methods to Harness Wave Energy
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Methods to Harness the Energy
This is the Oscillating Water Column Method
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More on the OWC

• About 36 kW of power potential per 1 meter wave
  front.
• You must assume a rectangular profile of the
  wave, since waves are not rectangular this
  potential cannot be reached.

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Wave Energy Problems

• The best place to put these devices is usually in
  the areas of the ocean with the strongest waves,
  but these places are also the most difficult to
  set up the generators, and maintain them.
• Oceanic waves are generally too slow (frequency)
  to rotate a turbine efficiently.
• The electric cables that bring the energy to the
  mainland could also be a possible threat to sea
  life. Tests on this are currently being conducted
  to see if it would really be a problem.
• Like wind turbines, wave energy converting
  devices are currently expensive.

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Yes, that says friction
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Wave Energy Equation

• Power Per Unit Length0.5A2?gv
• A Area of the waves cross-section
• ? Density of water
• g 9.8 m/s2
• v Velocity of the wave
• You might also see the potential energy stored in
  one wavelength as Ep.5A2??gL

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Proof
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Sample Problem
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• Activity time