Abstract:

The influence of turbulence intensity (TI) on the tip speed ratio for maximum power coefficient, here called λ_Cp-max, is studied for a 200 kW VAWT H-rotor using logged data from a 14 month period with the H-rotor operating in wind speeds up to 9 m/s. The TI - λ_Cp-max relation is examined by dividing 10 min mean values in different turbulence intensity ranges and producing multiple C_P(λ) curves. A clear positive relation between TI and λ_Cp-max is shown and is further strengthened as possible secondary effects are examined and deemed non-essential. The established relation makes it possible to tune the control strategy to enhance the total efficiency of the turbine.