A new concept for a mini ducted wind turbine system

Wind energy is foreseen to represent one of the most important drivers in the transition to a clean energy system. On one hand, the major trend is to increase the turbines’ height and rotor size so as to improve the economy of scale. On the other hand, another approach that is receiving large interest is the so-called Ducted Wind Turbines that allows to significantly improve the turbines performance with reduced dimensions aiming at designing systems that could be integrated in the urban environment. This paper studies the optimal configuration of a mini- Ducted Wind Turbine by analysing, through numerical simulation and critical discussions, several different configurations varying the most critical geometric features of the system. The impact of such changes is analysed at varying wind speed and direction so as to also test the omnidirectionality of the system. Results of the final model are then compared with a similar turbine installed in open field showing that thanks to the mini Ducted Wind Turbine system is possible to exploit up to 432% more energy than a traditional system. Nevertheless, the final system still does not present a full omnidirectionality as it experiences an inversion of flux for wind directions that are contrary to the turbine axis. Finally the numerical simulations have been validated through the wind tunnel tests. The results show that for low air velocity 5–6 m/s, there is a perfect correspondence between the numerical and experimental values and the relative percentage difference between the two methods is less than 1%.