Wind Turbine Blade Design
Why do irrigation windmills (on farms) have a higher blade surface area than electrical generation turbines?
It seems strange that the rotor chosen for most electrical turbines is a three-blade design. I don’t understand why a much higher surface area design (i.e. the rotor of an irrigation windmill — the ones you see pictured in any Americana photo of a large farm) is not employed to catch a larger amount of wind. Does it have to do with bird mortality? Also, do electrical turbines have any ability to steer directly into the wind, as you see a weather vane do?
Wind turbine generators definitely have the ability to change their direction according to wind conditions. On the very large turbines, there is usually a smaller weather station on the top of the nacelle to measure wind speed and direction. Inside the nacelle (that’s the ‘body’ of the turbine, on top of the tower, to which the blades attach), the turbine control computers direct motors to adjust the turbine into the wind.
The control computers also adjust the pitch of the turbine blades, to catch more or less wind, depending on power output and wind conditions. This is very similar to the propeller technology used on airplanes.
The old-time windmills of the Americana era are simple fixed-blade designs that were intended to be cheap and withstand a large range of wind conditions.
In modern wind turbines, each blade is a highly engineered, carefully controlled, very expensive device. And, each blade is HUGE compared to the little windmill blades. Long-term studies have compared many different blade designs, and found that 3 blades is the most acceptable tradeoff considering cost, performance, reliability, and ability to extract useful energy from the wind.
Vertical Offset Wind Generator Blade Design – Part #1
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Windmax HY400 500 Watt Max 12-Volt 5-Blade Residential Wind Generator Kit $649.00 Advantages of 5-blade wind turbines over 3-blade wind turbines 1) 5-blade wind turbines will greatly improve annual energy production in low wind conditions. For areas with average wind speeds of 11 MPH (5m/s). If you compare annual energy output to conventional 3-blade wind turbine, there is an increase of annual energy output of more than 60%. 2) 5-blade wind turbines will dramatically improve … |
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Windmax HY1000-5 1,000 Watt Max 24-Volt 5-Blade Residential Wind Generator Kit $1,099.00 Advantages of 5-blade wind turbines over 3-blade wind turbines 1) 5-blade wind turbines will greatly improve annual energy production in low wind conditions. For areas with average wind speeds of 11 MPH (5m/s). If you compare annual energy output to conventional 3-blade wind turbine, there is an increase of annual energy output of more than 60%. 2) 5-blade wind turbines will dramatically improve t… |