Marine air-conditioning systems face high energy consumption, particularly in humid marine environments. This study is an experimental investigation of the effects of rotating wheel speed and regeneration temperature on the performance of the system, which is a dual-stage desiccant dehumidification fresh-air pre-treatment system using ship waste heat as the regeneration heat source and seawater-assisted cooling to improve the efficiency of energy use. The results showed that the dehumidification capacity and efficiency of the system improved with an increase in the rotating wheel speed from 6 to 10 r/h and in the regeneration temperature from 80 °C to 110 °C. Optimal performance was achieved with a rotating wheel speed of 10 r/h and a regeneration temperature of 110 °C, balancing the maximum dehumidification capacity, energy efficiency, and waste heat utilization.

This study evaluates integrated shipboard freshwater production and fresh air pretreatment on a 20,000 TEU-class container vessel, addressing its freshwater demand and the inefficient recovery of exhaust waste heat from the main engine. The system integrates rotary dehumidification, seawater condensation, and water purification. A theoretical model was developed to evaluate the system performance, incorporating design, thermodynamic modeling, parameter optimization, and adaptability analyses under various operating conditions. The results indicate that under optimal conditions (seawater at 25 °C, outlet temperature difference of 2 °C), the single-stage system is predicted to produce approximately 1.45 m³ of freshwater per day, meeting 20.7% of the vessel’s freshwater requirement. The auxiliary electrical energy consumption, estimated based on standard engineering correlations, is 1–1.5 kWh/m³, representing a 70–80% reduction compared to conventional reverse osmosis systems (3–6 kWh/m³). The sensitivity coefficient for seawater temperature was −0.334, whereas that for output temperature was −0.167. A two-stage series configuration has the potential to further improve the demand satisfaction rate to 41–61%. Overall, the proposed system enables the cascade utilization of ship waste heat and functional integration of air pretreatment and freshwater production, offering a promising auxiliary engineering solution for energy conservation, emission reduction, and onboard freshwater self-sufficiency in marine applications.