Enhancing Energy Efficiency in High-Speed Craft: A Trigeneration Energy Recovery System for LNG-Fuelled Vessels in the Mediterranean Sea

This work presents an integrated energy recovery system for high-speed craft, which was developed to improve fuel efficiency and reduce emissions in maritime transport. The proposed system consists of three subsystems: cold energy recovery from LNG vaporisation, an organic Rankine cycle, and a Seebeck effect generator for waste heat utilisation. A comparative evaluation of five organic fluids was conducted to identify the optimal working fluid for both the cold energy and organic Rankine subsystems, with R1233zd(E) giving the highest efficiency. The results indicate that the proposed energy recovery system can reduce fuel consumption and emissions, achieving CO₂-equivalent reductions of up to 1,784.7 tons annually. These findings highlight the potential of combined energy recovery technologies in aligning maritime operations with increasingly stringent environmental regulations.