Vertical Axis Windmill Turbines

The little brother of the HAWT, the Vertical Axis Windmill Turbine, or VAWT, is a lesser known type of windmill. In HAWT design, there is a basic concept, not much variation, a typical model. In VAWT design, there are three basic models: Darius, Lenz2, and the Savonius.

The Savonius is a drag-type turbine, which means it works in the same way as a cup anemometer. The blades on a Savonius can't rotate faster then the speed of the wind, so they generate a high torque. They are the most inefficient VAWT design, because of the drag technology. They generally cannot self-start. These are best suited for grinding grain or pumping water.

The Darrieus turbine uses lift-technology. It is better suited for electricity generation than Savonius. They generate less torque.

A Lenz2 turbine is a hybrid between the two. It uses both lift and drag technology in a safe, efficient, slow running turbine. It is the newest species of VAWT, created my Ed Lenz over a course of four years.

Of course, this is only a snippit of information on each type. We will get into more specifics on each type later, as well as my theories on design. 

Darrieus Turbine

Lenz2 Turbine

Savonius Turbine