Your Questions About Wind Turbines For Home Use
Robert asks…
How to build a home wind turbine to replicate a commercial one?
I am doing a school project and need to build a wind turbine with the same dimensions as a commercial one. Any help would be appreciated along with some references.
admin answers:
The most important thing is to have LOTS and LOTS of money.
If you are a billionaire, that would be a good start.
Charles asks…
Why are wind turbines built with blades stationed vertically?
Wind turbines are built like a clock, with the blades stationed vertically. However, this seems to limit it – the blades only spin when wind is blowing in two directions.
However, if the blades were placed horizontally, spinning like a merry-go-round, it seems like it would be much more effective. If constructed in this manner, wind could blow in all directions and move the blades.
admin answers:
Hey Michael, Ben is correct about the vertical type turbines. The reason none of the power companies use them, is because they are horribly inefficient. Most of the energy absorbed by the downwind blade is used forcine the upwind blade back into position for the next cycle, and very little is left to produce power. Typically, this type of wind turbine, called a Darrieus Rotor, is about 5 to 8 % efficient, meaning less than 1/15th of the winds power is converted into useable torque, or electricity, and the rest is just wasted churning the blade around in the wind. Horizontal units, and in particular the 2 or 3 blade units generally operate at about 30 to 35 % efficiency, or about 6 times more efficient than a comperably sized Darrieus Rotor. The smaller home sized units like ours have a tail that constantly turns the unit to face the wind regardless of where it is coming from. Older farm type turbines with 12 or 15 blades on them usually worked this way too. That type of turbine, with the multitude of wide flat blades were almost never used for electrcity generation, they were also not very efficient. In most cases, they were used to pump water, and in that way what was needed more than efficiency was low wind start up torque. The large multiple blades worked better for this, but tended to stall out in higher winds. Electrical generating wind turbines work much better in high winds and at high RPM’s, so fewer blades is ideal for this.
The really large utility sized turbines you see that have no tail are either fixed to face one direction where the wind is almost always blowing from, like along the coast, or they have a small anemometer on top that senses the winds direction, and a computer uses a small gear motor to physically turn the unit to face the wind if necessary. These are typical in the midwest. Darrieus Rotors, and their close cousin, the Savonius Rotor, are really neat looking devices, and they are great for small garden pond pumps or outdoor garden lighting, but they are ill equipped to produce enough power to run even a household refrigerator. There is a great article at the American Wind Energy Associations website written by Mick Sagrillo about this, if you want to learn more, check it out. Mick is considered by many in the renewable energy world to be the modern day guru on wind power. Take care Micheal, Rudydoo
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