homemade practical 3kw wind turbine generator

[Salah Al-doais]

hi guys:
I have been interested in wind turbine energy for more than 2 years,yet I have not built my own .
i am living in Sana'a where air density is lower than normal.but in the area where I live the wind speed is good(or seems to me).
I plane for only 2 blade rotor with 3 m length for each blade.ending up with 6 m diameter rotor which is surprised to be much higher than I need with assumed min wind speed of 10 m/s
with of low Co value of 0.3 as my math I should have about:
P equals:3*3*3.14*0.97*.5*10*10*10/1000 which makes about 13.70 kw and by considering Cp:
we end up with 13.7*0.3 which makes about 4.11kw.?
what are my chances ?? the most I worry about is low wind speed below that 10m/s.
your help is of great appreciation.

[Rob Beckers]

Hi Salah,

Welcome to the forums!
Looks like Sana'h is at 2250m altitude. That's high! Air density is only about 80% of what it is at sea level. Your numbers look about right regarding power.

For energy production it's the average wind speed for your area that counts. To get an idea of what to expect from a turbine that is something you may want to look into. Normally a Weibull distribution is used for wind speed, so once you know the average wind speed the distribution can be approximated, and by multiplying that with the expected power curve (output for each wind speed) you'll get energy production.

By the way, every company that has attempted 2-bladed wind turbines has come to regret it. For a hobby project it doesn't matter too much, but keep in mind that 2 blades invites a number of issues.

-RoB-

[Salah Al-doais]

thank you Rob for the response,
I have a little concern about the power control, assuming that my cut-in wind speed is about 5 m/s and rated speed is 10m/s and cut-out speed is 15m/s how would the turbine react when below rated speed is dominating..