Modeling a hybrid Rankine-cycle/fuel-cell underwater propulsion system based on aluminum-water combustion

► Underwater propulsion using aluminum-water combustion for high energy density. ► Included SOFC for eliminating H2 venting, improved efficiency, depth independence. ► Developed scaling methods to link thermodynamics to system energy density. ► 2.5- to 7-fold range improvement over batteries with aluminum combustor system. ► 3- to 4-fold improvement over batteries (and no H2 venting) when SOFC is added.