Experimental analysis of installing multirotor horizontal wind turbines in a ducted wind turbine: The influence of rotor diameter and rotation on power efficiency optimization

The current study focuses on applying duct and multi-rotor wind turbines to enhance the generating capacity of a wind system arrangement in response to the expanding enthusiasm for using renewable energy sources in the municipal area. The outcome of this research can be utilized to introduce optimal turbine arrangements for a range of wind speeds related to specific regions to optimize the amount of power that can be extracted. It can produce power on standalone or in collaboration with other systems, such as Airborne and Invelox configurations. A duct speeds up the wind flow through the turbine location, while additional turbines can capture the remaining energy in the turbine's wake. For this aim, the impact of various configurations of multi-rotor wind turbines mounted on a recently designed duct was explored, followed by an investigation into enhancing the total output power. The effect of rotating direction and rotor diameter has been examined by comparing multiple arrangements to achieve the most significant output power for wind speeds ranging from 4 to 16 m/s. The outcomes prove that in high-speed winds of 12 m/s or more, mounting one rotor with a smaller diameter in the middle of two larger ones within the duct while spinning in the counter-rotating situation enhances the power efficiency by up to 95 %. Moreover, in low-speed winds of 6 m/s or lower, the three rotors with the same diameters presented the highest output, almost 2.1 times compared to the single rotor mounted in the duct throat. Considering an appropriate arrangement for multirotor wind turbines regarding privileged wind speed in the region can significantly increase generated power.