Potential of solid oxide fuel cells as marine engine assisted by combined cooling and power cogeneration systems

•Four cogeneration systems integrated with solid oxide fuel cell are proposed.•Waste heat recovery systems were adopted for cooling and power cogeneration.•Multi-objective optimization of four integrated systems.•Energy, exergy, economic and environmental performance analyses were conducted. Switching to solid oxide fuel cell-gas turbine in marine applications can contribute to carbon reduction strategy. Integrating waste heat recovery technology can potentially meet the required cooling and power demands. This paper presents four combined cooling and power systems, each combining solid oxide fuel cell-gas turbine, supercritical CO2 cycle, and refrigeration cycle integration. First, the thermodynamic models of the four systems were constructed. Next, the performance of each integrated system was studied based on energy, exergy, economic, and environmental metrics. A multi-objective optimization approach was then applied to each system, balancing efficiency with cost. Results showed that the environmental penalty cost rate was 5.24 $/h at a fuel molar flow rate of 1.4 mol/s. The solid oxide fuel cell-gas turbine, regenerative supercritical CO2 Brayton cycle, and ejector expansion refrigeration cycle system offers the lowest cost rate of 44.40 $/h. Meanwhile, the solid oxide fuel cell-gas turbine, regenerative supercritical CO2 Brayton cycle, and absorption refrigeration cycle system achieves the highest energy efficiency (77.35 %) and cooling capacity (86.39 kW), indicating superior thermodynamic performance. This article provides a reference for the application of the solid oxide fuel cell-waste heat recovery system in marine transportation.