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Experimental Determination of Optimum Design Configuration for Micro Wind Turbines at Low Wind Speeds

This paper reports experiments and theory on some small wind turbines of rotor diameter 100 cm and less. Discrepancies in power performance have been found from predictions of blade element theory. Wind tunnel experiments showed that performance depends on the solidity of the fixed diameter rotor due to the dependence of Reynolds number on chord length. In particular, power output is lower than theory predicts on wind speed less than about 10m/s. For turbine rotors of constant diameter, output depends on solidity. In general, at low wind speeds, rotors with greater solidity give a higher output than with less solidity. This is due to the difference in Reynolds number, which itself is associated with chord length. The optimum value of Reynolds number for such small turbines is 100,000.