Wave Tank Testing of the Wavebob

Name of Applicant:  Wavebob Ltd.
Grant Award:  €43,200
Category:  Shared Cost R&D
Completion Date:  October 2004

Introduction

The research and development of an innovative and entirely Irish wave power device has been progressing steadily since 1998.  The Wavebob is a floating and self-reacting device that may be deployed in large arrays in deep offshore waters.  It is of a type known as an oscillating point absorber, meaning that most energy is absorbed when the natural period of oscillation is in tune with the incident waves, and that the width of the device is small with respect to the wave length.

Sea waves vary in period and in height.  A key advantage of the Wavebob is that it is fully tuneable to the prevailing wave climate and has an adjustable bandwidth.  Stroke length is also controllable; this is critically important in terms of survivability and allowing useful power to be recovered from larges waves.  As such the Wavebob is intended to be an ideal device for the sometimes very energetic seas off Ireland’s West coast.

Linear and non-linear models have been developed in-house, based on earlier hydrodynamic analysis.  These computer models have been validated using true-scale models in wave flumes and tanks, in turn increasing the accuracy of and confidence in virtual testing using the computer models.

The primary goal is to develop a practical and commercially licensable product.  The key parameters are survivability, capital and operating costs, and average annual useful power.  Once survival is assured, the goal is then to deliver useful and acceptable power to the grid at a competitive price.  In Ireland that translates to being competitive in terms of price, quality and quantity with wind power.

Survivability and capital and operating costs are being addressed in parallel R&D programmes, as are also the detailed design and testing of the (hydraulic) power take-off and control systems.  The object of the present RD&D project, part-funded by SEI, is to measure the power produced by true scale models in accurately generated wave spectra.

Current Status

The RD&D project is well advanced and the interim report submitted.  Tests have been completed at 1/50th and 1/20th scale using the facilities of the Hydraulics and Maritime Research Centre (UCC, Cork) and the large wave channel of the German Coastal Defence Centre (Hanover University and the Technical University of Braunschweig).  Analysis of the results from the tank tests correspond closely with predictions from the validated numerical models.

For further information contact:

William Dick
Wavebob Limited
Blessington
Co Wicklow

Tel:  045 865233
e-mail:  william.dick@clearpower.ie