Abstract
With the increasing global demand for energy and environmental awareness, the interest in sustainable energy solutions has grown over the last years including wave energy. In this thesis there is a literature study on Wave Energy Converters (WEC) and a theory chapter on the power in ocean waves. The thesis work was done in in collaboration with CorPower Ocean (CPO), an innovative company developing a WEC. Two buoy shapes, both with two different weights were investigated and a comparison made on the effect of latching on power absorption. The work can be separated into two main parts, a numerical simulation and experimental tests.
A numerical model incorporated with a mathematical description of CPO Power Take-off (PTO) physics was used to simulate and obtain numerical results on the buoy behaviour in select sea states. The benefit of latching was obtained by comparing passively heaving buoys to latch controlled buoys. The simulation model was used for various analysis of the system.
Experiments were performed at 1:30 scale on the same buoys in a tank facility. Information about the hydrodynamics of the buoy, motion and power absorption was obtained and the effect of latching on the power absorption found. Results on natural period and radiation damping were obtained and a drag coefficient was estimated.
The results show that phase control by latching can substantially increase the power absorption of a point absorber and broaden the range of waves it can operate in. Agreement was found in the numerical model and the experiments when investigating the benefit of latching compared to passively heaving.