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Testing the Crestwing energy converter at Aalborg University


Crestwing´s absorption capacity has been tested in Aalborg University´s wave tank, mostly in irregular 2D waves, in 2008 by the University's Department of Civil Engineering. 

                                                                                                                                                                                               

              

 

 

 

 

 

 

 

The purpose of the study at AAU was to develop the Crestwing concept under different physical configurations and setups, and through optimization of the efficiency to define the concept.

Extract from the conclusion of the AAU Final Report

Based on power production tests over all the 5 standard waves states showed that in the assumed length scale of 1:30 the device can achieve an overall efficiency (the ratio between the mechanical power available to the PTO system and the power in the waves arriving at the width of the device, averaged over long time, i.e. a year) of 37 %.Based on an established non-dimensional power matrix for the device the effect of device size on overall efficiency was analyzed. It was found that increasing the size from the approx. 70 m (corresponding to the assumed length scale of 1:30) to 100-110 m would increase the overall efficiency by approx. 40 % if no limitations were put on the installed capacity.

 

Estimated energy production after the test session (December2008), based on the detailed development of the WEC and especially on the optimization of scale (power matrix), has demonstrated the potential annual energy intake from a full scale plant in the North Sea to approx.1000MWh.

In summary, the conclusion is positive with a test result showing that Crestwing concept is among the most efficient flow concepts.

Power matrix

 

 

Testing the Crestwing energy converter at DHI, Hoersholm, Denmark

The Crestwing has in 2010/11 been tested in DHI’s deep water tank, mostly in irregular 3D waves,  at a scale that is a sufficient basis for planning and realization of a full scale plant at a selected site.

Concerning future calculation and construction, the Response Amplitude Operators (RAOs) for movements, PTO Rod Forces, Mooring forces, hull and hinge forces were determined for all tests.

With the Crestwing final test, the Crestwing-concept is tested and developed on shore in a scale that is sufficient as a basis for planning and realization of the full scale plant at selected site.

The conclusive summary is positive with a test which proves, that the Crestwing-concept after the final test on DHI is among the most efficient floating WEC installations worldwide


The tests at DHI were primarily oriented toward construction including a safe and feasible method for anchoring and secondarily a good efficiency. We reached a low anchoring load which only slightly increased from sea state two meters. The forces in the PTO system were under the optimized test process, not increasing with increasing wave height.

The test was primarily oriented towards a safe and feasible method for anchoring and secondarily on an optimization of the absorber efficiency. The obtained absorber efficiencies confirmed the AAU process results.

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Crestwing on DHI

RAOs

                                                                     


                                                                                                                                                                             

 

Crestwing final test follow-up offshore

Crestwing at a scale of 1:5 is being tested on site at Frederikshavn in the period October 2011 to June 2012.

The purpose of the project "Crestwing final test follow-up offshore" is to demonstrate Crestwing off shore based on the recently completed DHI project "project Crestwing final test".


The aim of the trials are testing offshore and completing the DHI test 2010/2011 through:

  • testing of the mooring system off shore under the influence of currents and wind
  • testing the hull off shore under the influence of the currents and wind
  • testing and adjustment of the developed PTO system 
  • testing of the electricity-producing PTO system offshore.

Through "Project Crestwing final test", we have developed a planning and design tool, and one purpose for "Crestwing final test follow-up offshore" is the calibration of this tool through the offshore process.

 

        Waveenergyfyn Nyborg afd. Kissendrupvej 15 5800 Nyborg / Frederikshavn afd Cilovej 8 9900 Frederikshavn