Rotor Diameter (\( D_r = \sqrt{\frac{8 P_e}{\pi \rho \xi V^3}} \)):

Where:

• \( D_r \) is the rotor diameter, in meters (m).
• \( P_e \) is the electrical power, in watts (W).
• \( \rho \) is the air density, 1.25 kg/m³.
• \( \xi \) is the overall system efficiency, typically 0.2.
• \( V \) is the wind velocity, in meters per second (m/s).