Sridhar Condoor of Saint Louis University has developed a tubular turbine for tight spaces; it has no central shaft, so it can be mounted over existing structures like chimneys, cell-phone masts, or yes, as Ariel at CleanTechnica put it,
Its hollowness allows it to be placed around existing objects— so you could literally have a tree-hugging turbine.
The New Scientist describes it:
The outside of the turbine is a cylinder that is incised with inlets to catch the wind from any direction and toothed on the inside to drive a gear that powers a generator.
A cylindrical frame within allows the main cylinder to rotate freely and can be mounted around another object - either vertically or horizontally. That makes it possible to install without needing clear space, and could even provide a way to hide ugly features, the patent says.
Systems, apparatus and methods for generating power from fluid motion, such as wind are provided. The apparatus is a wing-shaped airfoil with cup-shaped indentations that allow the airfoil to harness wind energy throughout a wide range of wind speeds and from different wind directions. The indentations harness wind energy at low wind speeds while the wing-shape generates a lifting force at high wind speeds to harness wind energy. The system comprises one or more of the devices configured in a hollow, generally cylindrical, shape and connected to a ring frame. The system rotates about an axis running through the center of the ring frame. The rotational motion of the system generates electrical power via a generator. The method is a method for generating electrical power from the rotational motion of the system.
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