Assessment of IEC Normal Turbulence Model and Modelling of the Wind Turbulence Intensity for Small Wind Turbine Design in Tropical Area: Case of the Coastal Region of Benin

Abstract

The wind turbulence intensity observed on a site have an influence the wind turbine energy production and the lifetime of the blades. It is therefore primordial to master this parameter for the optimization of the production. So therefore, this study is interested on the modelling of the wind turbulence intensity at 10 m above the ground on the coast of Benin. Four years of wind data measured on the site of Cotonou Port Authority (PAC) from 2011 to 2014 and recorded with a temporal resolution of 10 min were used. From the transport equation of turbulent kinetic energy followed by a numerical simulation based on the Nelder-Mead algorithm developed under the Matlab software, we proposed five new models for estimating the wind turbulence intensity. The results of the different simulations reveal that four of proposed models and based on the roughness, the speed of friction and the length of Obukhov better fit the data, during the periods of January, April, June, July, August, September and December. The estimators of the Root Mean Square Error (RMSE) and the Mean Absolute Error (MAE) vary from (0.02; 0.01) in December to (0.09; 0.07) in August. As for the model which is a function of roughness and the wind shear coefficient (expressed only according to the wind speed), it gives better performance whatever the time of the year and the atmosphere stability conditions. The estimations errors are included between (0.02; 0.01) obtained in December and (0.08; 0.06) observed in March. A comparative study between the existing models in the literature and the best model proposed in this study showed that only this model gives the best adjustment with the data. It can therefore be used on the sites where turbulence is influenced by the roughness and the atmosphere stability. Finally, from this model a new wind turbine design class has been proposed for the site of Cotonou. It takes into account the actual levels of turbulence observed and thus allow to optimize the energy production. ©2020. CBIORE-IJRED. All rights reserved

Study and Design of a Horizontal Axis Wind Turbine (0.5 kW) Using Software Solid Works

“…In the case of this study the average turbulence index I is equal to 0.2 according the works to Donnou et al [21].…”

Design of Vertical Axis Wind Turbine Darrieus Type (H- Darrieus Rotor) of 0.20 KW from the Software Topsolid

“…In Benin, according to the work of Awanou et al [10], Houekpoheha et al [11], Akpo et al [12], Salami et al [13], Donnou et al [14], the southern coastal region of the country is likely to be home to wind installations for small and large-scale electricity generation. However, this region is exposed to fluctuations in wind speed and direction that could slow down the proper functioning of wind turbines, according to the work of Donnou et al [15]. To cope with these difficulties, vertical axis wind turbines (VAWTs), which are devices with the advantage of being insensitive to changes in wind direction, having a smaller number of components with very low noise emissions and a three-dimensional structural design, are therefore positioned as a credible alternative [7].…”