Laboratory tests on an original wave energy converter combining oscillating water column and overtopping devices

This work presents an experimental study of an original Wave Energy Converter (WEC) in which the energy is harvested by means of the Oscillating Water Column (OWC) and the Overtopping approaches. Scale-model tests were conducted in the wave flume of LABIMA at the University of Florence in the framework of the EU-FP7 MARINET project. The studied WEC embodies a classical OWC device where the water column conduct is hydraulically connected to a second oscillating column though which water overtops into a reservoir above the mean sea level. The wave energy can thus be converted by an air turbine and a low-head water turbine (Figure 1). The effectiveness of this kind of WEC was investigated in a scale-model under the excitation of regular waves for different wave height, period and steepness. The water column oscillation inside the two chambers, the overtopping of water and the free surface level in the reservoir are measured as function of the incident wave height and period. Data analysis on terms of power extracted as air flux and water discharge is performed and the capture width of the device is presented.