Innovative design of a sea wave energy harnesser

Abstract

The aim of this research is to design and develop a simple, light and cost-effective wave energy conversion device. The mass to power ratio is of importance to achieve high working efficiency. In addition proper control concept is proposed for various sea wave conditions to manage the system optimally. The potential wave resource in South Africa is enormous as there are over 2000 km of coastline with an annual wave height average of 2-3 m. One of the most efficient wave energy extractor is the hinged wave energy converter (HIWEC) whereby the wave force is applied to a responsive mechanism able to resist the working force of the waves. The hinged mechanism used in this project is of the power take-off (PTO) type. The PTO captures the wave energy and then between the wave’s time intervals transfers it to be converted and stored. Control of the response of the HIWEC can be achieved through active tuning of the PTO. As wave energy is intermittent, the supplied electrical power will show strong variations unless an energy storage system is available. The energy storage system consists of several series connected gas accumulators, placed in the hydraulic circuit to produce a smoothing effect.