Waste heat cascade utilisation of solid oxide fuel cell for marine applications

Abstract To cope effectively with the world’s energy shortage and environmental pollution, a fuel cell combined with waste heat recovery technology has gradually become the best option for large ship power generation equipment. In this investigation, a combined system comprising a solid-oxide-fuel-cell-gas-turbine subsystem, supercritical carbon dioxide cycle, organic Rankine cycle, ammonia-water absorption refrigeration cycle, and high-pressure reverse osmosis desalination plant is introduced and analysed. Not only the power output of the system is calculated, but also the contribution of cold energy is considered by calculating its equivalent power. The results illustrate that the equivalent net output and thermal efficiency of the system are 278.82 kW and 67.03%, respectively. Compared with the solid oxide fuel cell, the power output increases by 86.35 kW and the fuel efficiency increases by 20.7%. Additionally, the system can provide 5.95 kW of cold energy and 0.94 m3/h of fresh water for the crew under the condition of maximum power output. To summarize, the proposed novel system design can realize the combined production of cold energy, electric energy, and fresh water, and it exhibits the characteristics of high efficiency and cleanliness.