CFD investigation on wind power harvesting from small-scale wind turbines for powering residential buildings in New Zealand

Abstract

As an alternative solution, wind power could be harnessed by designing and implementing small-scale wind turbines for distributed power generation. In this work, 3-dimensional time-domain numerical simulations, based on the Reynolds-Average Navier-Strokes (RANS) model, are conducted for two categories of small-scale wind turbines, i.e. drag force- (Savonius) and lift force-driven (Darrieus) ones, while placing them at a flat surface and a step height, respectively. The present results confirmed that placing a small-scale wind turbine at a step height can improve the maximum power output, respectively, approximately 219.2% for the Savonius wind turbine and 121.0% for the Darrieus wind turbine operating at their optimum stage; moreover, the corresponding peak power spectral density of the turbine torque is improved by 173.9% and 83.6%, respectively. In addition, the power generated from the wind flow could reduce the CO2 emission. It has been observed that the Savonius turbine could reduce the annual CO2 emission by 3,738.9–19,857.8 kg and that of Darrieus turbines by 4,919.6–26,128.8 kg. This study demonstrated the benefits of adopting forward facing steps to improve wind turbine performance in a typical urban environment.