Study on Spray Enhanced Heat Transfer Performance in Offshore Hydraulic Liquid Piston Compressed Air Energy Storage System

Offshore wind power is a promising renewable source, yet its intermittency requires efficient, large‐scale storage. This study proposes a seawater‐based dual‐chamber hydraulic liquid piston compressed air energy storage system directly coupled with an oscillating wind turbine. A coupled thermodynamic‐bond‐graph model is developed to represent multipath heat transfer among air, spray droplets, seawater, and chamber walls. Parametric analysis is conducted on seawater flow rate, spray flow rate, and spray angle. Results indicate that at a seawater flow rate of 300 L min −1 , spray flow of 20 L min −1 , and spray angle of 90°, compression and expansion efficiencies reach 92.2% and 94.3%, while the indicated efficiency (IE) and round‐trip efficiency (RTE) attain 81.9% and 61.9%. Increasing spray flow strengthens heat transfer and raises IE and RTE to 84.1% and 63.83%. Spray angle exerts a nonmonotonic effect, with 90° providing optimal droplet distribution and the highest efficiencies. These results confirm that spray‐assisted thermal management, with seawater as both piston and heat sink, is an effective approach to achieving near‐isothermal performance and high cycle efficiency in offshore energy storage.