Performance analysis of two different sizes of wind turbine rotors based on Nigerian low wind regime

Abstract

Nigeria can reduce its level of dependency on fossil fuel by making use of wind energy which is an indigenous renewable energy source for electricity generation. For large energy generation, large wind turbine is more preferable over a wind farm of smaller wind turbine units that will generate the equivalent amount of energy because, there will be loss of energy due to transmission and generation system of every turbine unit of the wind farm while the larger turbine has only one transmission and generation units. However, smaller wind turbines are generally more efficient than the bigger ones in terms of wind energy conversion and they are therefore good for small power generation. In this research work the performance of two different sizes of small wind turbine rotors, a 4-metre rotor (D4-Rotor) and a 4/5-metre one (D4/5-Rotor) were studied at 6m/s wind speed using numerical method. The POINTWISE software is used for modelling the rotor blade and meshing the flow domain. The software used for the simulation is ANSYS 20 which uses finite volume method (FVM) of analysis for solving governing flow equations. From the result of performances, the D4/5-Rotor has higher power coefficient (0.2995) than that of D4-Rotor (0.237), and this indicate about 26 per cent performance improvement of the smaller rotor. Conclusively, smaller wind turbines are more efficient than the bigger ones in terms of wind energy conversion and they are therefore good for small power generation especially in low wind regime.