Aero-structural design, manufacturing and testing of a 1 kW roof-top wind turbine blade for a hybrid wind-solar system

This paper highlights the aerodynamics and structural design of a 1 kW rooftop wind turbine with a robust mounting capable of supporting the turbine at a high wind speed of 59.5 m/s with the objective of maximum power production at an 11 m/s wind speed prevailing over a two storey building. The wind turbine blade has been designed using the Gottingen 682 airfoil and blade element momentum theory. A numerical model with shear stress transport (SST) k-omega turbulence model based on computational fluid dynamics is implemented to calculate the power generating capacity. The turbine produced a maximum shaft power output of 1.1 kW at 550 rpm, corresponding to an 11 m/s rated wind speed. Composite wind turbine blades are manufactured using glass fiber and an epoxy matrix through a vacuum bagging technique. Static structural analysis is performed for the rated, cut-off and extreme wind speeds, and the corresponding tip deflections are 0.74 mm, 3.96 mm and 22.85 mm respectively. Under the extreme wind speed, a maximum flap wise bending stress of 14.5 MPa occurs on the pressure surface and a compressive stress of 13.5 MPa arises near the root, which has a safety factor of 2.37. The total weight of the composite blade based on computation and fabrication is 887 g and 895 g, respectively. In order to study the dynamic behaviour, modal analysis is performed and checked for resonance conditions through the Campbell diagram.