The hydrodynamic performance of a heaving point absorber as a wave energy converter near a large body is studied through numerical modeling. First the study is performed for an individual point absorber in the absence of large structure and the results are compared with the results available in the literature. Next, the performance of a point absorber floating in the vicinity of a large body, which is considered as a fixed vertical wall, is investigated. The efficiency of the power absorption in regular and irregular seas is examined based on different floater sizes, floater shapes, drafts, wave heading angle and positioning of the floater. Numerical simulations are based on hydrodynamic forces and coefficients, obtained with the commercial software WAMIT.

No abstract

While renewable energy is generally considered to be a well-researched field, wave energy converters (WECs) are still in early industrial stages, for example due to high costs, even though the potential of WECs in countries such as the UK is very high. Apart from the power plant location, the amount of power generated by a wave energy converter is also highly influenced by the efficiency of both the energy transfer from the wave to the plant’s generator and the power take-off (PTO) itself. Improving on any of these aspects therefore increases the power output and economic attractiveness. Based on a commercial development project by the NEMOS GmbH in Germany, this paper presents a more efficient means of connecting a floater and a rotary PTO based on a free traction mechanism consisting of a custom belt and matching pulley. In addition to regular longitudinal forces, the belt system can transfer transversal forces of up to 14 % of its pulling force and allowing run-in angles up to 8°. First tests show an average efficiency to 99.6 % in wet conditions. The paper lays out the theoretical background of the new design and discusses existing alternatives, before detailing the taken approach to design and optimization. The results are validated and compared to an existing rope design and a benchmark flat belt.