Experimental investigation of semi-submersible platform combined with point-absorber array

Highlights: • Provides a program for experimental investigation of floating point-absorber array. • The efficiency of the floating converter is better than a single floater at a low wave period. • The staggered arrangement of floaters is beneficial for power output. • Floaters' elimination effect can improve the platform's motion responses. The deep ocean contains abundant wave energy but the sea condition is complex for people to obtain ocean energy. Therefore, how to develop a floating wave energy converter that adapts to the severe environment of the deep ocean has become a hot research topic recently. In this paper, a point-absorber array is installed on a three-pontoon semi-submersible platform and a model experiment of such a system is conducted under regular and irregular waves. And, a simplified hydraulic power take-off (PTO) system is adopted to convert wave energy into potential energy of load inserts. Results show that such a combination increases pitch and heave, but the surge is suppressed under certain circumstances. The maximum hydraulic efficiency of the point-absorber array is 35.2%, and the max overall efficiency is 11.1%. Additionally, by comparing performance of each floater in the array, the staggered arrangement of floaters is more conducive to energy harvest.