http://www.cansolair.com/wimdphotos/large_top%20(1).jpg

I got intrigued by this system when I read about it in Dr. Bruno Eck's book on Fans. Unfortunately, although he mentioned the location of the experimental model's first erection, he did not mention the name of the inventor and gave no reference, so for some time I could go no further. Then I happened to pick up the Wind Power volume of the UN proceedings on New Sources of Energy and there it was.

Thus stimulated, I began to analyze the system. I completely neglected parasitic losses because I was only interested in induced losses, that is losses inherent in this type of system - one in which the wind turbine also acts as a centrifugal inducer. The problem, in short, is that minimum momentum loss in the air exhausted from the blades corresponds to the point of zero power output; the details are in my worksheet in the directory mentioned above, or ask and I will email it to you direct.

Depending on the orientation of the exit nozzles on the turbine-blade tips, what I call pneumatic efficiency reaches a maximum of 73% with the nozzles pointing anti-spinward, and 30% with radial exit of the induced air. This efficiency can be regarded as the percentage of the Betz limit that could be extracted with NO PARASITIC LOSSES. As others have already commented, parasitic losses can reasonably be expected to be high in this kind of rig.

Even so, it has one sterling quality lacking in every other type of turbine - namely that it is self-braking and, within generous limits, self-regulating even with fixed output nozzles. If the output nozzles can be re-oriented, say by a flyweight, from tangential to radial, the braking effect is enormous. This would be a great advantage in an area where the wind is strong and gusty, especially one where the turbogenerator set must operate unattended. Antarctica and mountain-peak communication relay sites come to mind.