New Swanturbine Project

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The first stage of research involved the design and testing of a fully instrumented 1m diameter prototype device. It was designed to be tested in a series of towed experiments using the University Research Vessel, 'Noctiluca'. A range of flow speeds and rotational speeds were tested under controlled conditions. The performance is then measured using hydrodynamic and electrical efficiencies.

 

The prototype is a direct drive flow turbine the device is designed to operate in flows of between 3.5 and 5.5 knots and incorporates an adapted Permanent Magnet Generator [PMG]. The power rating is 1.5kW and the rated speed is 200rpm. A gearless low speed generator offers a high efficiency over a range of speeds with minimal maintenance demands through the use of novel structural and electromagnetic topologies.  A simple, robust and serviceable yawing mechanism is used for maximum flow capture and the use of patented materials, developed by Corus will form the gravity base.

The PMG is advantageous when used in this application in conjunction with blade over speed. Designing for over speed allowed a favourable compromise between starting torque and PMG efficiency. This is illustrated by an overall power coefficient of 0.24. The next phase is envisaged as a six-month installation to investigate the turbine response to tidal cycles and the long-term effect of the marine environment.

As with any energy source, the cost of producing the electricity is of primary importance. The Swanturbines design incorporates various features which are designed to allow minimum cost and optimum performance. One of these features is gearless drive train the optimised relationship between blades and generator. This was validated during the experiments and produced very high efficiencies.

The combined design philosophies; simplicity and reliability, lead to a design that is both cost effective and robust for the harsh marine environment.