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Author Topic: generating electricity through windpower  (Read 3153 times)

paul.fr

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generating electricity through windpower
« on: 03/11/2007 21:16:15 »
My goal is to one day own and live in a windmill, how efficient would the sails be at generating electricity? or would it just be better (or possible) to fit a modern turbine to the windmill?


 

Offline Alandriel

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generating electricity through windpower
« Reply #1 on: 03/11/2007 21:29:15 »
Windmill for you - water mill for me  ;D... and run the whole house on self-generated electricity  ;D ;D

Perhaps someone can answer and consider both of them. I'm certainly interested too
 

another_someone

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generating electricity through windpower
« Reply #2 on: 03/11/2007 23:21:53 »
Windmill for you - water mill for me  ;D... and run the whole house on self-generated electricity  ;D ;D

Perhaps someone can answer and consider both of them. I'm certainly interested too

Hydroelectric power is nothing new, but it is a very finite resource - there is only just so much flowing water available to generate energy for human use.  All very nice to think about it as a free supply of energy for you - but it is not so free when someone builds a watermill upstream from you, and thus consuming most of your power.  It takes a lot of land to collect the water, and allow it to fall over sufficient distance to have any meaningful amounts of energy, and if you don't own all of that land, then are you not steeling someone else's energy?
 

another_someone

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generating electricity through windpower
« Reply #3 on: 03/11/2007 23:42:58 »
My goal is to one day own and live in a windmill, how efficient would the sails be at generating electricity? or would it just be better (or possible) to fit a modern turbine to the windmill?

I don't know exactly what the relative quantitative efficiency of traditional windmills and modern wind turbines are, but the following are qualitative differences I can imagine.

Firstly, clearly, modern aerofoil design on wind turbines should be more efficient that old fashioned wind mills.  Part of this may be offset by having a greater area of sail on a windmill than the wing area of a modern wind turbine.

Secondly, the windmills are designed to turn very much slower than the new wind turbines.  This may have some advantage is reduced parasitic drag, but also creates less lift (again, offset by using greater sail area); but more specifically, the slow speed may be useful for directly turning millstones, but is too slow to directly drive electric generators.  Even modern windmills often need to be geared up to drive electric alternators, but the gearing on old fashioned windmills would have to be even greater.

This brings us to another area, the efficiency of the internal mechanisms, as frictional losses through gearing and bearings.  Modern wind turbines are designed with better materials and better mechanical design.  These could be offset by leaving the external aspects of a windmill, but replacing the internal mechanics so that they would function more efficiently.

Now for the real problems.

Modern wind turbines operate higher off the ground than old fashioned windmills.  The higher you are off the ground, the faster (and cleaner - i.e. less turbulent) the air stream you are in, and so the more energy you can extract from the air stream.

Modern wind turbines are much lighter than old fashioned windmills (I am referring here to the weight of the moving parts, not the weight of the base).  This means that modern wind turbines can more rapidly be adjusted for changes in wind direction and wind speed than could old fashioned wind turbines, and so could be operating in more optimal conditions for a higher percentage of the time in which the operate.
 

lyner

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generating electricity through windpower
« Reply #4 on: 04/11/2007 17:59:08 »
I bought a wind generator for my boat. It cost about £350 and was lousy value in terms of £ per kWh. But it is convenient and I can convince myself it is 'free energy'. It means my battery is never flat when I want to start my engine.
Great in a rare situation but, for generating my home electricity supply - 'marginal' is the kind word for it.
 

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generating electricity through windpower
« Reply #4 on: 04/11/2007 17:59:08 »

 

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