Power performance of canted blades for a vertical axis wind turbine

Small scale vertical axis wind turbines have a number of advantages for deployment in an urban environment but are subject to highly varying thrust and radial aerodynamic forces. Helical blade shapes for vertical axis wind turbines can reduce load fluctuations during turbine operation; however, a helix has complicated three-dimensional geometry that can be difficult to manufacture resulting in expensive blades. A new blade configuration based on twisted straight blades that are mounted at an angle to the vertical, a cant, has been developed and tested in a wind tunnel in a number of different configurations and conditions. They offer the benefits of distributing the fluctuating aerodynamic loads, but incorporate a linear axis so that they can be manufactured at a comparable cost to simple straight blades. The power performance data from the tunnel testing show that canted blades have comparable power output to similar straight blades and that aerodynamic fences can be used to improve power performance.