Performance analysis of a novel hybrid device with floating breakwater and wave energy converter integrated

As a kind of clean energy, wave energy has attracted increasing attention in recent years. However, due to its high cost and low efficiency, wave energy has not been widely commercialized worldwide. According to previous research works, the combination of wave energy devices and floating breakwaters can reduce the cost of wave power generation devices efficiently. In this paper, a hybrid device with wave energy converter (WEC) and flexible porous floating breakwater integrated is proposed. The hydrodynamic performance of this device is studied by numerical simulation based on Reynolds-Averaged Navier–Stokes (RANS) method which has been validated through experimental results. Based on this, a series of numerical simulations are performed under different power take-off stiffness (K_PTO) and different power take-off damping coefficient (CPTO) to calculate the motion and transmission coefficient of the device. By comparing the numerical results, the influence of K_PTO and C_PTO of the hybrid device on its wave attenuation performance and energy conversion efficiency are analyzed. The results indicate that under the incident waves of period 0.56 s and 0.89 s, the recommended value of K_PTO is 3.0 N/m and 0.5 N/m respectively. While for incident waves of period 0.56 s, in order to achieve better wave attenuation performance and power generation efficiency, the recommended value of C_PTO should be between 10.55 Ns/m and 14.23 Ns/m. On this basis, the influence of the size of breakwater on the wave attenuation performance and power generation efficiency of the hybrid device is also discussed. Moreover, through a cost analysis, it can be inferred that the utilization of the baseline model is more economically viable.