Pneumatic Air Compression Wave Energy Converter (PAC-WEC) for Low-Energy Wave Climates

This study describes the modelling, fabrication, and experimental evaluation of a magnetically levitated pneumatic wave energy converter (PAC‑WEC) designed specifically for low‑energy wave climates. A coupled hydromechanical–pneumatic model was developed to represent the motion of a magnetically levitated oscillating disc under regular wave excitation, the resulting air‑pressure variations, and the flow conditions at the turbine inlet. A fully 3D‑printed laboratory‑scale prototype was tested under 12 controlled wave states (H = 0.10–0.20 m, T = 0.25–1.50 s), yielding airflow velocities of between 3.54 and 11.12 m/s with strong sensitivity to the wave height and period. Through complementary computational fluid dynamics optimisation, an eight‑blade turbine configuration with a 180° flow orientation was identified as the most torque‑efficient design. Based on the measured airflow velocities, the estimated electrical power output reached approximately 3.6 W under short‑period, large‑amplitude wave conditions, whereas it decreased to about 0.12 W under long‑period, small‑ amplitude waves, with these two operational extremes corresponding to volumetric energy densities of roughly 227 W/m³ and 7 W/m³, respectively. The results demonstrate that the integration of magnetic levitation with pneumatic compression provides a viable, friction‑reduced conversion pathway for low‑energy seas and provides a validated foundation for the development of compact, near‑shore wave energy systems.