Experimental studies on the PTO system of a novelfloating wave energy converter

Experimental studies were carried out on the power-take off (PTO) system of a novel floating wave energy converter with a built-in cross-flow turbine. The pitching motion of the device causes a column of water to rise and fall periodically in a caisson which creates a bi-directional flow. The cross flow turbine uses this bi-directional flow to rotate in one direction only. The PTO system was experimented using a 6 DOF ocean simulator at a model to prototype scale of 1:3. The experiments were conducted for varying pitch angles, moment of inertia on shaft, wave periods, and rotational speeds. It was found that for all pitching angles, the device had optimum response at a wave period of 3 seconds. A moment of inertia of 0.053 kgm2 was found to be appropriate for all test cases. Peak hydraulic efficiencies between 35% - 45% were obtained for the range of 40 – 50 rpm for most test cases.