Study of a novel multi-generation system for nuclear-powered merchant ships

For ocean-going vessels, stable power production and sufficient energy supply are essential. This study proposes a nuclear-powered combined cooling, heating, power, and freshwater system. Based on a 69 MW nuclear-powered merchant ship, the system achieves cooling through steam extraction-driven absorption refrigeration cycles while innovatively integrating membrane distillation desalination units to recover low-grade waste heat from condensers. Thermodynamic analysis and cost evaluation models are established to assess system performance. Parametric analysis shows that under rated propulsion power conditions, higher split ratio and main steam pressures enhance economic performance. An optimal generator temperature for maximizing system efficiency, achieving a primary energy ratio (PER) of 39.52 %, exergy efficiency (η_ex) of 63.26 %, with a corresponding minimized levelized cost of energy (LCOE) of 0.01065$/kWh. Further exergy destruction and capital cost analyses indicate the steam generator accounts for the largest exergy loss (32.1 %), while turbine constitutes the major capital investment (36.68 %). The proposed multi-generation system demonstrates an attractive payback period of 9.3 months. Compared with the original system, the multi-generation system demonstrates superior thermodynamic and economic performance, which provides an important theoretical basis and practical guidance for the integrated design of future energy systems for nuclear-powered ships.