The proposed technology is a revolutionary vertical axis wind turbine (VAWT) that solves three major problems associated with wind turbines today. The first is high manufacturing/maintenance costs, the second is low efficiency, and the third is safety in stormy weathers. The developed turbine, fig (1) consists of a disc(s) and flat surface blades that can rotate about vertical shafts parallel to the main turbine shaft. The blades can only rotate relative to the disc(s) in one direction, and are restrained from rotating in the other direction by pin(s) (or other means) attached to the disc(s). As the wind flows over the turbine blades the restrained blades generate rotational torques, while the non-restrained blades are in opposing position to the turbine motion. Typically, the presence of opposing blades in vertical axis wind turbines is responsible for their lower efficiency compared to Horizontal axis wind turbines. In our design, the opposing blades (the non-restrained blades) will be rotated out of the way by the wind, thus eliminate the opposing forces. In addition, as the opposing blades are being rotated by the wind, they gain momentum that is transferred to the turbine disc(s) through a pin(s) or can be stored to energize the blade at low wind speeds. Preliminary calculations of that energy is estimated at 35% of the turbine total energy.
A unique braking system of the present invention is an aerodynamic brake. In stormy weathers to stop the rotating turbine, the restraining pins will (1) be removed and the blades will be free to rotate to align with the wind direction producing zero torque that will stop the turbine rotation, fig (1D), (2) restrain the blades in position normal to the wind direction thus produce equal load on the blades that generate torques that cancel each other, fig (1C). The uniqueness of this braking system is that the turbine blades are stress free. In conclusion: (a) the use of flat blades reduce the expensive manufacturing/ maintenance typical of VAWT airfoil blades, (b) the dynamic blades will improve the turbine efficiency by removing the resistance of the opposing blades and impart additional momentum, and (c) the aerodynamic brakes automatically align/ restrain the blades with the wind direction/ normal to wind direction producing zero net torque.