Vertical!

I was ambling through an article on the use of vertical axis wind turbines in new age buildings and came across (amidst a mess of calculations) some different designs for vertical turbines. It seems that some of them use a tunnel effect and some design the blades to shed wind. The tunnel is far better for single direction wind because the returning blades don't have to go against the wind at all. The other style "Savonius" is designed to shed wind which is less efficient but doesn't rely on the direction of wind making it useful for areas that have rapidly changing wind directions. I would think that the wind tunnel version is not worth making because a horizontal axis turbine would be better, although the article discusses the incorporation of these turbines into buildings and a horizontal axis turbine would be difficult to put on a building due to many factors.