The Power of Wind

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					   The Power of Wind

By: Anthony, Michelle, and Emily
             Vogt
Blast from the past
   Charles F. Brush’s 60 foot,
   80,000 pound turbine that
   supplied 12kW of power to
   350 incandescent lights, 2
   arc lights, and a number
   of motors at his home for
   20 years.




             Classic ‘Dutch
             Style’ Wind Mills




                                 In 1941, a full-scale futuristic looking wind turbine was built on
                                 a mountain top in Vermont and hooked up to the system of the
                                 Vermont Public Service Corporation as an auxiliary power
                                 source. Mounted on a 110 foot steel tower, its twin 56-foot
                                 blades were designed to develop 1,2Kw at a wind velocity of
                                 30 mph. Under favorable conditions, it actually developed
                                 1,4Kw.
 Currently the biggest and most powerful
 wind turbine in the world is the Enercon E-
 126 wind turbine (pictured above)
 generating 6Mw.

The MadLev is a magnetically levitated wind turbine
that can generate one Gigawatt of power (enough to
power 750,000 homes) and delivers clean power for
less than one cent per kilowatt hour using this wind
turbine.
Magnetic levitation is a very efficient method of
capturing wind energy. The blades of the turbine are
suspended on a cushion of air, and the energy is
directed to linear generators with minimal fiction
losses. The MagLev wind turbine was invented by
Ed Mazur, a researcher of variable renewable
energy sources since 1981. There are already
several MagLev wind turbines in operation in China.

       The M.A.R.S. (Magenn Power Air Rotor
       System) is an interesting device that is
       capable of harnessing the power of the wind
       (pretty much like how a windmill works) to
       generate electricity, sending that power
       down a 330 meter tether rope for immediate
       consumption. Since the M.A.R.S. is filled
       with helium, it is capable of flying much
       higher than other wind turbines in order to
       gain access to higher wind speeds.


       The E1500 model turbine is a home windmill and
       sports a very unique wing design that operates
       with low vibration and at wind speeds as low as 1.6
       m/sec. The efficiency specs on the turbine are
       vague — “43% power performance at optimum
       wind speeds”.
•   Assumptions:
                                                 Betz Law
•   v 1 = The average wind speed through the rotor area is the average of the undisturbed wind speed before the wind
    turbine,
•   v 2 = The wind speed after the passage through the rotor plane

•   The mass of the air streaming through the rotor during one second is

                                                       m = ρ F (v 1 +v 2 )/2
•   m = mass per second
•   ρ = density of air
•   F = swept rotor area
•   [(v 1 +v 2 )/2] = average wind speed through the rotor area.

                                                                                        Wind power going glam.
•      According to Newton's second law:
        – The power extracted from the wind by the rotor is equal to the mass times the drop in the wind speed squared:

                                                                P = (1/2) m (v 1 2 - v 2 2 )


•      Substituting m into this expression from the first equation we get the following expression for the power extracted from the
       wind:


                                                      P = ( ρ/4) (v 1 2 - v 2 2 ) (v 1 +v 2 ) F

•      Now, let us compare our result with the total power in the undisturbed wind streaming through exactly the same area F,
       with no rotor blocking the wind. We call this power P 0 :


                                                            P 0 = (ρ/2) v 1 3 F


•      The ratio between the power we extract from the wind and the power in the undisturbed wind is then:


                                           (P/P 0 ) = (1/2) (1 - (v 2 / v 1 ) 2 ) (1 + (v 2 / v 1 ))

•      We may plot P/P0 as a function of v 2 /v 1 :

    We can see that the function reaches its
    maximum for v 2 /v 1 = 1/3, and that the
    maximum value for the power extracted from
    the wind is 59% or 16/27 of the total power
    in the wind.
Diagram
  maximum amount of energy we
  can get from the demonstration
              model
• The entire surface is 1.6cm * 6.1cm * 60blades
• density of the air in phoenix
• The speed of the fan is about 14mph which
  converts to 6.25856mps
• The maximum amount of energy possible from
  under these conditions is? 5.6watts
• From the equation Watts = Volts * Amps we get
  Watts = (1.1)(0.002)=0.0022Watts

				
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posted:7/27/2012
language:English
pages:7