Performance Evaluation of Experimental Rim-Drive Wind Turbine

The current paper discusses an on-going research effort in the performance evaluation and optimization of rim-drive wind turbines (RDWT). Unlike conventional aerofoil wind turbines, the RDWTs are designed to extract power directly from the outer rim instead of central hub. A RDWT with 25ft rotor diameter is tested for performance evaluation and maximum power extracted. The experiment is conducted at Wind Science and Engineering research center, located in Lubbock, Texas. The wind turbine is coupled to a variable speed direct drive electric generator. The induction current in the generator is optimized for different wind speeds in order to extract maximum power from the wind turbine. The experimental results are compared with two commercial aerofoil wind turbines of similar design specifications using performance evaluation data published by National Renewable Energy Laboratory. It is observed that RDWT can extract comparable and often higher amount of energy when compared with aerofoil wind turbines. The results also show that RDWT has an average power coefficient of 0.3 and can operate in wider spectrum of wind speeds than aerofoil wind turbines.