Numerical and experimental analysis of the power output performance of a point absorber WEC for nearshore wave conditions
Jonathan Everett, Vladislav Sorokin, Colin Whittaker, Kean C. Aw
Abstract
A single-degree-of-freedom Wave Energy Converter (WEC) that harvests energy from heave and surge motion of waves in nearshore conditions has been designed. The device targets supplying energy to aquafarms and attaches to an existing structure. The device consists of a buoy that slides up and down with waves along a linear rail, with this linear motion converted into the high-frequency rotation of a generator using magnetic coupling. The effects of mounting orientation (angle of linear rail to the vertical) of the device on the power output were studied for a range of wave parameters. A scale model was manufactured and tested in a wave flume, using mono-frequency waves in intermediate water depths. The study reveals that increasing the mounting orientation angle enhances power output across all tested frequencies. The results show a power increase of up to 50% with a 45-degree mounting angle compared to 0 degrees, with an average increase of 35% across the considered frequencies. Time-domain modelling in Simulink complements the experimental investigations, providing similar results to the experimental study. In summary, this study demonstrates the efficacy of the designed single-degree-of-freedom WEC for energy harvesting in nearshore conditions, emphasising the critical role of mounting orientation in maximising power generation. • A wave energy converter that provides electricity to aquafarms is developed. • The point absorber uses magnetic coupling and a linear to rotational mechanism. • Increasing the device’s angle with respect to vertical maximises power output. • Experimental results show 12.6 W of power output with a 6.4 kg moving mass.