http://en.wikipedia.org/wiki/Savonius_wind_turbine

that link sums it up. Cheaper and more reliable, but less efficient

In most things I try and get efficiency, but when I build a solar collector or a windmill, I primarily want reliability and a cheap build....one can always increase the surface area of a solar collector with more units, if they are cheap to build.

The same with windmills, build a second one or build it bigger!!! If its cheap to make!!

When collecting completely free energy, is silly to waste thousands of $$$$$ just on the grounds of efficiency!!!! When a larger/more of them, but cheap unit will catch the same amount of energy as the expensive smaller one!!!

The end result is the amount of energy captured and the sum total of the financial investment!!!

Of course if you are a millionaire, then expensive is good.....

To quote from the article you linked:-

Savonius turbines are used whenever cost or reliability is much more important than efficiency.

I can admit that in some cases, cost and reliability are the watchwords. Airfoil type of systems seems to be the winners in these large windfarms. I suspect that if you built a high S-rotor it would have so much drag that the cost advantage may well vanish with the structure costs.

this site is devoted to them

http://www.berezin.com/jeff/Savonius%20Wind%20%20Turbine%20News.htm

http://www.ettridgewindturbine.com/

http://www.motherearthnews.com/Renewable-Energy/1974-03-01/The-Savonius-Super-Rotor.aspx

Good Answer-my vote for you. I've found it very useful as I've been toying with the idea of building vertical axis wind turbines for quite a while and your post has triggered a strong will to get down to build one or more! This is particularly useful for home and village applications-regardless of efficiency, the cost is affordable for a variety of uses at "POINT-OF-APPLICATION".

Thanks again.

Sri Ramakrishna, I share your passion for designing a wind turbine for rural India. The only windmills other than the big electricity generating grid connected machines on wind farms which I have seen in our country are the old wind pumps. I think these are vintage 19th century design. Surely we can build a better turbine today. I wish we could meet and talk in more detail. I am in Trivandrum.

I am in the process of adapting the Savonius windmill (S-Rotor type).Immediately I have something useful on hand, I'll update you through CR4. Unfortunately,I am not a team man, as I have found myself effective only when working alone and at my own unhurried pace. Please bear with me till then.

Regards

D.Ramakrishna Naidu

I understand your need to work alone. However as you are in Chennai you might approach Centre for Wind Energy Technology (C-WET), which is the governmental agency for wind energy research, and has its headquarters in Chennai. They may help you. I wrote to them once, but no reply. Any way wishing you luck.

"I wrote to them once, but no reply."

Precisely the reason why I don't waste time hanging around in the "Reception" halls of these grandiose institutes and their chauvinistic "Scientists". I had recently sent details of my idea of a proposal of great national and international importance, responding to their advertisement calling for ideas and proposals for development assistance. They agreed it was a great idea but indicated their inability to take it up!! This is despite the fact that the idea had International acceptance and a very gigantic American corporate was willing to take it up. I was not willing to give it to anybody other than to my own countrymen and have paid the price for "Misplaced" patriotism.

There is nothing better than "SELF HELP IS THE BEST HELP". So I am happy to plod on for the sake of humanity. Thanks anyway for your encouragement.

hi,

Thanks for your interest.

Yes, an S-rotor installed high enough may cause drag which might be difficult to handle. But then the idea here becomes reworking the material, and accordingly the design of the turbine, so that the wind-gen sustains strong wind current apart from enjoying the maximum torque.

What I wanted to know about the S-Rotor and its Applications is the parameters which Savonius considered while proposing the Persian model as against the European model of HAWTs. What he must have had as a premise is imagination for me until I get my hands on the original article.

Till then, waiting...waiting...