KES - Kite Energy Scheme

Lead Research Organisation: Imperial College London
Department Name: Aeronautics

Abstract

Accurate knowledge of the aerodynamic forces, particularly drag and the limits of the lift coefficient for stable operation are essential for the design of an efficient kite energy system. The system in the present project also involves autonomous manoeuvring of the kite and therefore knowledge of control derivatives is very important. Lift, pitch and roll moments induced by small changes in camber at the trailing edge, and downward curvature at the tips (anhedral) will therefore be studied. Because of the importance of drag, effort will also be directed to the minimisation of the parasitic drag of the bridle lines. The Imperial College contribution to the project will measure the above listed aerodynamic forces under controlled wind tunnel conditions at reduced scale. The results will be compared with field testing experience obtained in another section of the project and then used as inputs to the analysis tool which predicts the operational characteristics of the kite energy system. The second contribution from Imperial College will be to extend and validate the modelling of the kite aerodynamics under orbiting and manoeuvring conditions, in particular developing the wake modelling to achieve greater accuracy and understanding of the issues raised by running two kites with operational overlap in the system, and to consider effects of mean wind shear and turbulence.

Planned Impact

The UK offshore wind sector is projected to grow to £8bn by 2020 so the economic benefits estimated to result from the new kite energy modelling tool could be considerable across the UK investment. Research results will be communicated through the project partners and publication in relevant journals.

Publications

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Description A key finding of the wind tunnel testing has been that the drag coefficient of an open-nose aerofoil section suitable for use as sections of a ram-air parafoil does not deteriorate as much as expected from the clean closed aerofoil performance. This is important for energy capture efficiency..
Exploitation Route They may be relevant to other uses of parafoils, including recreational use and possible defence use.
Sectors Aerospace, Defence and Marine,Energy,Leisure Activities, including Sports, Recreation and Tourism

 
Description A major finding of the wind tunnel testing has been the changes in drag coefficient of an aerofoil cross-section of a ram-air inflated parafoil between the condition when the leading edge region was partial open to provide inflation at close to total pressure conditions compared with the same aerofoil section with the leading edge closed. This was communicated in a report to the industrial partners who were designing the kite system for efficient wind energy capture. As at 2022 - Kite Power Systems (KPS) and their IP were acquired by a Norwegian company Kitemill in 2020. Kitemill have continued this kite power development but with significant changes in the design of the kite itself from the ram-air parafoil design which Imperial College tested in the large wind tunnel to a more conventional rigid wing. Successful test flights have been completed during 2021 leading to the Kitemill report that the system is now close to commercialisation.'
First Year Of Impact 2018
Sector Energy
Impact Types Economic