Study on Efficient and Stable Energy Conversion Method of Oscillating Water Column Device Based on Energy Storage Valve Control

Despite extensive research on the performance of Oscillating Water Columns (OWC) over the years, issues with low energy conversion efficiency and unstable power generation have not been addressed. In this study, a novel OWC energy conversion system is proposed based on the working principle of energy storage valve control. The system utilizes accumulators and valve groups to enhance the stability of energy conversion. The hydrodynamic model of the OWC system and the pneumatic model of the novel power take-off (PTO) system are developed using numerical simulations. Building on this, the impact of the incident wave period, wave height, and air chamber opening ratio on the system’s total hydrodynamic performance are examined. The results from the hydrodynamic analysis are subsequently used as input conditions to evaluate the proposed PTO system’s performance. The results show that the hydrodynamic efficiency of the system presents a tendency to increase and then decrease with the increase in the incident wave period, and an optimal period exists. The air chamber opening ratio has a notable influence on the hydrodynamic characteristics of the OWC system, and the larger system damping could be set to achieve a higher capture efficiency in the low-frequency water environment. The incident wave height has a lesser effect on the hydrodynamic characteristics and the resonant period of the device. The designed novel PTO system can effectively improve the energy conversion stability of the OWC device, the flow volatility through the turbine can be reduced by 53.49%, and the output power volatility can be reduced by 25.46% compared with the conventional PTO system.