Why is the surface area in the blades of windmills so small? I can think of dozens of windmill designs where the surface area would be tens of times bigger with the same building costs, and yet all the windmills have this same crappy design. Why? Someone explain this to me, i dont get it
two reasons..the bigger the blades the faster it turns..which is not what you want for a windmill of that type..and bigger the blade the more damage to the system in high winds
just because the blades are turning slow doesnt mean the generator inside is turning that slow..by using the proper gearing system inside the generator is turning more revs than the blades..just like an altenater on a car does
because by using the proper gearing inside we can make the inner part turn many times faster than the blades themselves which is the main system of generating power - - - Updated - - - and also the faster the blades turn the louder the noise
riiiiight....... but if the goal is to produce the maximum amount of energy then why is that important? And i seriously doubt the noise is the issue here.
wind turbines is another example of the failure of liberals, democrats, and republicans. Billions of public tax money diverted to a failed source of energy.
Thank you for this comment. It was just what i was looking for. And secondly, im not so sure about that, i think it might make sense some day. With the right technology.
That gearing ratio does not change because the blades are turning faster... the inner gears would just be turning even faster, generating even more electricity. I second the OP's question.
The blades of Wind Turbines are replaced every 10 years, give or take a few years. The Wind Turbine blades are 35 tons or more of fiberglass, it takes a lot of energy and raw materials to make one Wind Turbine. To make a Wind Turbine you need oil, you can not construct a Wind Turbine without oil, it takes energy to melt sand into fiberglass (2000`-3000`f), it takes chemicals such as propene which only comes from oil. Green Energy uses more oil and natural resources at a faster rate than all other forms of Energy. When there is no more oil, we can not make Wind Turbines. Using more faster is not Green nor Renewable, depleting natural resources at a faster rate is not Green nor Renewable nor Sustainable.
thats what i said..its not the speed of the blades ..by using the gears you make the turbine turn faster..
You can make those blades out of cloth if you want to xd Thats a silly argument. - - - Updated - - - t The speed is irrelevant here, what matters is the maximum amount of energy you can get out of it.
speed of the blades doesnt determine the amount of electricity it puts out..the blades are not in direct drive with the turbine..they rotate at different speeds..just like a car ..lets say your engine is running at 3500 rpms..do you tires turn 3500? no they are slower..why gears in the transmission and rear end..so reverse the gearing and this is how the blades turn slower than the turbine
Higher surface area actually does not increase efficiency much beyond a certain point. The narrow blades already greatly reduce the speed of the wind passing by. Making the blades thicker would not help as much, since the blade is at an angle, and the additional surface area would be collecting the wind that has already been slowed by the leading edge of the turbine. You also have to consider the speed at which the blade spins. It actually has an effective surface area to collect wind greater than that when the turbine is not moving. I am sure there are trade-offs when making the blades thicker or longer, and I think it is safe to assume that engineers have carefully considered all this for the most practical design.
After a lot of reading the answer seems to be a combination of things, all of which have been mentioned I think. The addition of blades adds efficiency, but at a diminishing return. So if you have 1 blade and add a 2nd, it is 6% more efficient say, but adding a third is 3 a fifth is 1.5 etc. This greater efficiency can turn a hub harder/faster, but this means a LOT more wear and tear evidently, not to mention noise (which I couldn't care less about). So they cost a lot more, and they wear out quicker with more blades. In short, the return does not justify the output. 3 long thinnish blades appear to have an optimal return. The "fat part" of the blade face is a lot bigger than it looks like too.
At high wind speeds, turbines with larger blades are unstable...but to answer your question. There are several factors that affect voltage produced, but we'll just focus on the Bernoulli Effect.. This involves the lift and drag components of the surface area of the blade and the angle of the blade. A greater surface area creates more drag because the resistant air has more area to push against...the angle of the blade also has a significant effect on drag.
Smaller surface means less air resistance. Old Dutch wind mills have the ability to change the pitch of the wicks and also the amount of surface by changing lining with ropes. Can the pitch of the blades on modern wind turbines change in angle? And the gear box also.
