Wind Energy Flashcards
Factors effecting on power of a wind generator
Size of rotor blades
Speed of wind
Efficiency
Location and design of system
Equation for energy available to a wind turbine
KE (J) = 0.5 x mass (kg) velocity (m/s)2
Factors effecting wind energy available to a turbine
Density of air
Swept area of blades
Velocity of air
Density p, kg/m3
Air outside, when warmer has a lower density
Air outside, when colder has a higher density
Low temp= High density= high wind energy= more electric= more money
Swept Area of blades (Area m2)
Force is directly proportional to Area
Available wind power of wind turbine
Power= 0.5pAv3CP
Power available to wind is proportional to:
Density of air
Swept Area
Cube of velocity
Betz Limit
Max Fraction of power in wind that can be theoretically extracted for use is 16/27 or 59.3% (in reality can be anything from 40%-20%depending on the design of the system)
Other Factors effecting max energy production
Air Density
Hub Height
Reasons for Betz limit
Turbulence
Energy losses in gearbox, generator and bearings.
Wind down steam after passing through turbine
Density effect on power
P is directly proportional to density
Warm temperatures air density decrease
Cold temps air density increase
Altitude effect on power
As altitude increases air density decreases so power production reduces.
Temperature effect on power
Temp High temperatures particle move further apart so air density decreases so power decreases
