Wave Energy Converter Integrated with Breakwater: Experimental Investigation of Hydrodynamic Efficiency

Wave energy conversion integrated with breakwaters can share costs between coastal barriers and energy production, thereby improving the cost-effectiveness of wave power generation. An Oscillating Water Column (OWC) design for the wave energy integrated breakwater is chosen, as there are no moving parts underwater, and the material used is marine concrete. These choices will significantly reduce the required maintenance and any corrosion damage to the Wave Energy Converter (WEC). The OWC device is integrated into a caisson breakwater and designed as a fixed bottom-standing structure. The long-term objective of this study is to perform experimental model testing of an OWC WEC breakwater design. These tests quantify the errors found in experimental testing due to friction losses and present the results deemed valid according to energy conservation. The incoming incident wave is separated from the outgoing reflected wave in the post-processing of the wave data. The power absorbed by the OWC is computed by multiplying the average flow rate of the oscillating water inside the chamber by the pressure differential across a damper. Energy balance is used to analyze the friction losses in the system that is unaccounted for. The incident and reflected wave measurements are conducted using the incident and reflected wave decomposition from Lin and Huang's four-probe method. We study the Capture Width Ratio (CWR – ratio of absorbed power to incident power on width of device) for various damping levels and wave frequencies. The results depict the CWR reaching close to its maximum of 2 for 3 damping levels. A comparison is made between the damping levels as the mid-damping level has the highest peak, and the highest damping level provides a wider range of power absorption in terms of frequencies or wavelengths.