A 3D Study of the Darrieus Wind Turbine with Auxiliary Blades and Economic Analysis Based on an Optimal Design from a Parametric Investigation

Abstract

Due to the high consumption of energy in recent years and global efforts to replace fossil fuels with clean energy, the need for high-efficiency renewable energy systems has become necessary. Small VAWTs are suitable candidates for clean energy production, due to their advantages over other power systems; nevertheless, their aerodynamic performance is modest. This paper attempts to improve the Darrieus VAWT performance by examining the turbine design parameters through the CFD method by adopting the SST k-ω turbulence model and finding the optimum turbine by utilizing the Kriging optimization model. Finally, by using the suggested optimized turbine, the economic analysis conducted to assess the total net present cost indicated the ideal hybrid power. The CFD results from different parameters show that the three-bladed turbine achieved maximum Cp and turbine with σ = 1.2 and optimal Cp by 34.4% compared to the medium solidity. The symmetrical airfoil t/c of 21% registered 19% and 48% performance enhancement at λ = 2.5 in comparison to t/c = 15% and 12%, respectively. Increasing the H/D ratio results in a better performance at the initial TSR, while a low H/D attained the highest Cp value. The stall condition can be delayed in low TSRs with toe-out blades upstream and obtained an increase of 22.4% in power obtained by β= −6° compared to the zero pitch angle. The assistance of auxiliary blades working in a wider range of TSR is shown and the turbine starting power augmented by 75.8%. The Kriging optimization model predicted the optimal Cp = 0.457, which can be attained with an optimal turbine with N = 3, σ = 1.2, NACA 0021 airfoil, AR = 0.8, and β= −6° operating at λ = 2.8. Finally, the results of the economic analysis indicate that the hybrid energy system consisting of a VAWT, a battery, and a converter can be applied for satisfying the site load demand with a lower net present cost and cost of energy compared to other feasible hybrid energy systems.