Fully enclosed multi-axis inertial reaction mechanisms for wave energy conversion

This paper introduces a novel concept for wave energy conversion, using fully enclosed appropriate internal body configurations, which provide inertial reaction against the motion of an external vessel. In this way, reliability, robustness and survivability under extreme weather conditions – a fundamental prerequisite for wave energy converters – can be achieved. Acting under the excitation of the waves, the external vessel is subjected to a simultaneous surge and pitch motion in all directions, ensuring maximum wave energy capture in comparison to other wave energy converters like point heave absorbers. The internal body is suspended from the external vessel body in such an appropriate geometrical configuration, that a symmetric four-bar mechanism is essentially formed. The main advantage of this suspension geometry is that a linear trajectory results for the centre of the mass of the suspended body with respect to the external vessel, enabling the introduction of a quite simple form of a Power Take Off (PTO) design. Thus, because of this simplicity and symmetry of the suspension geometry and of the PTO mechanism, the fundamental restrictions of other linear, pendulum or gyroscopic variants on inertial reacting bodies are significantly removed