The efficiency of an oscillating water column (OWC) device for offshore wave energy conversion is affected by several parameters related to: a) the climate environmental conditions at the deployment location; b) the hydrodynamic characteristics of the OWC device as they are related to the design of the oscillating chamber; c) the characteristics of the installed air turbine; and d) the device’s position in the array relevant to the wave train propagation.
In practice, the geometry of an OWC is determined for the maximum energy potential sea state. Moreover, the position of the OWC array is fixed at the deployment location, thus the OWC cannot be adapted by itself to maximize the energy absorption at each different sea state. However, the air turbine characteristics in each oscillating chamber can vary rapidly, according to the frequency of the incoming wave, using an air turbine with pitch control.
The examined sea location of the present study is close to Sicily Island at the Mediterranean Sea. The environmental conditions of the examined location are defined by on site wave records. This study presents the methodology for the optimal Wells air turbine design at a given design sea state. Furthermore, passive rotor blade pitch control is investigated for maximizing the performance of the WEC system for several sea states.