Design of a new point absorber with a fully submerged toroidal shape

A new point absorber, equipped with a fully submerged toroidal shape, is designed to increase the power production of the WEC device, by properly matching the heave natural period of the floating buoy with the prevailing sea states at the deployment site. A non-linear time-domain model is developed and applied to assess the Annualised Energy Production and perform the strength check of the tensioned line, connecting the floating buoy to the Power Take-Off unit, lying on the seabed. Two candidate deployment sites, located in the Mediterranean Sea and in the Atlantic Ocean, are chosen for the possible deployment of a wave farm and the toroidal shape main dimensions are selected accordingly. Hence, a comparative analysis between a reference point absorber, consisting of a floating hemispherical buoy, and the new WEC device is performed to investigate the incidence of the proposed layout on the Annualised Energy Production. Finally, both Ultimate and Fatigue Limit State criteria are embodied for the strength check of the connection line. The new layout allows properly tuning the device heave natural period and increasing up to 60% the Annualised Energy Production, as regards the reference configuration, so making the marine energy more competitive on the international market.