Vertical Axis Wind Turbine Performance Based on Rotor Blade Radius

Significant amount of lately research is focused on improving performance of Darrieus type vertical-axis wind turbines (VAWT). This research explains the impact of rotor blade radius on tip-speed ratio, rotational frequency, starting wind speed, manufacturing costs and performance coefficient of Darrieus VAWT. To support the proposed explanations, a prototype with variable rotor blade radius was developed and tested in a wind tunnel. The conclusion is that blade radius should be decreased as much as possible until performance coefficient starts decreasing.