Experimental investigation on an energy-focused type OWC WEC array

Wave energy, as a renewable resource with vast global reserves, offers a promising solution to meet rising electricity demands and support sustainable energy transitions. However, achieving high conversion efficiency and ensuring survivability in extreme sea conditions remain significant challenges for existing wave energy converter (WEC) arrays. To address these challenges, this study presents a novel energy-focused type oscillating water column (OWC) array system that strategically exploits the multi-level wave energy concentration mechanism of parabolic walls. The system is developed within a framework that integrates a real-time wave field reassessment method, enabling optimal design of the OWC spatial layout and chamber diameter parameters, alongside a hierarchical OWC classification system (primary, secondary, and tertiary units) based on their respective positions relative to the focal point. Three distinct array layouts are designed and experimentally tested under various wave field conditions. The experimental results show significant performance improvements. Compared with the power output of a configuration with only the primary OWC, that of the array demonstrates a substantial increase. Furthermore, the 3-OWC array achieves a peak Wave-to-Wire efficiency of 63.6 % when spatially optimized, while consistently maintaining conversion rates above 25 % across all tested wave scenarios. In addition, the redistribution of hydrodynamic forces within the array configuration effectively reduces extreme wave loads on the primary OWC. Specifically, in the 5-OWC array, the wave force acting on the primary OWC is reduced by 66.7 %, confirming the system's dual capability for high-efficiency energy capture and enhanced structural resilience. Overall, the energy-focused type OWC array system shows significant potential for practical offshore power generation by combining improved energy capture capacity with enhanced system durability.