Analysis of a Concept for a Low Wind Speed Tolerant Axial Wind Turbine

In this paper, the authors analyze a design for a wind tower intended for areas of low wind speeds. The wind tower consists of a combination of several rooftop size turbines arranged alongside a cylindrical structure that acts as a Wind Deflecting Structure (WDS). The WDS amplifies the effective wind speed thus allowing the turbine rotors to operate under lower ambient wind speeds. Analyses were performed using simple models as well as more sophisticated CFD methods employing Steady and Unsteady Reynolds Averaged Navier-Stokes methodology. The effect of the wind amplification was shown on a commercial small wind turbine power output map. Also, a wind turbine rotor flow was computed as operating alongside the WDS and compared to the computed operation of isolated turbines at equal effective and ambient wind velocities. The computational analyses of this work suggest that the power output of isolated rooftop wind turbines deployed at low to moderate wind speed may be matched by installing wind turbines alongside a cylindrical wind deflecting structure operating at lower wind speeds. Other benefits of the arrangement are also enumerated.