The wind energy start-up evoblade, a spin-off of the Institute of Aerospace Technology (IAT) of the University of Applied Sciences Bremen, has developed a retrofittable spoiler for rotor blades with the help of Deutsche Windtechnik and Wirtschaftsförderung Bremen. The results of a side-by-side study of testing and optimising the EvoFlap now confirm that installing the spoiler can improve the aerodynamic flow in the area of the blade root, resulting in improved efficiency and performance of the system.
“Rotor blades have a significant impact on the technical and economic performance of a wind turbine,” said Dr.-Ing. Frank Kortenstedde, founder and CEO of evoblade. “By developing and optimising a retrofittable flow element, we wanted to achieve a technical and economic improvement in the properties of existing systems that leverages the advances in technical understanding.” Matthias Brandt, Director of Deutsche Windtechnik AG, added: “Even though retrofitting flow elements is not always an option, and the initial design and features of turbines are up to the system manufacturers, we are still very happy to participate in and support research projects like this that look at technologies of the future. The results are moving in the right direction and are helping the entire industry!”
Side-by-side study design with iSpin performance monitoring
The EvoFlap can be adapted to different rotor blade types. The NEG Micon NM 82 turbine type with a rated output of 1.5 MW and a rotor blade length of 40 m was selected as the basic system for the optimisation. The flow element was developed using the GFRP sandwich technique and has an overall length of 10 m. It is divided into seven segments to allow assembly directly on an installed rotor blade. “The blade does not have to be removed from the hub to allow EvoFlap to be installed, and this reduces the amount of work and costs,” Frank Kortenstedde emphasised. “Also, the blade structure is not damaged by gluing the segments onto it, and the EvoFlap blends harmoniously with the blade design.” To validate the annual energy output, the company ROMO Wind was commissioned to carry out independent performance monitoring using iSpin spinner anemometer technology. Measuring the wind speed in front of the turbine has the advantage that the reference wind speed is measured directly and undisturbed. In addition to the test system, a second (adjacent) turbine of the same type was equipped with iSpin technology as a reference system.
