Difference between revisions of "Wind Energy - Physics"

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<math>10^{3}</math> = k kilo = 1,000 = thousands  
 
<math>10^{3}</math> = k kilo = 1,000 = thousands  
  
10 6 = M mega = 1,000,000 = millions  
+
<math>10^{6}</math> = M mega = 1,000,000 = millions  
  
10 9 = G giga = 1,000,000,000  
+
<math>10^{9}</math> = G giga = 1,000,000,000  
  
10 12 = T tera = 1,000,000,000,000  
+
<math>10^{12}</math> = T tera = 1,000,000,000,000  
  
10 15 = P peta = 1,000,000,000,000,000
+
<math>10^{15}</math> = P peta = 1,000,000,000,000,000

Revision as of 16:29, 17 May 2011

Wind Power

The power P of a wind-stream, crossing an area A with velocity v is given by

 

It varies proportional to air density , to the crossed area A and to the cube of wind velocity v

The Power P is the kinetic energy

of the air-mass m crossing the area during a time interval

.

Because power is energy per time unit, combining the two equations leads back to the primary mentioned basic relationship of wind energy utilisation


The power of a wind-stream is transformed into mechanical energy by a wind turbine through slowing down the moving air-mass which is crossing the rotor area. For a complete extraction of power, the air-mass would have to be stopped completely, leaving no space for the following air-masses.

Unit abbreviations

m = metre = 3.28 ft.
HP = horsepower
s = second
J = Joule
h = hour
cal = calorie
N = Newton
toe = tonnes of oil equivalent
W = Watt
Hz = Hertz (cycles per second)







= p pico = 1/1000,000,000,000

 = n nano = 1/1000,000,000

= µ micro = 1/1000,000

= m milli = 1/1000

= k kilo = 1,000 = thousands

= M mega = 1,000,000 = millions

= G giga = 1,000,000,000

= T tera = 1,000,000,000,000

= P peta = 1,000,000,000,000,000