Proton-exchange membrane fuel cells with ejector-type anodic recirculation systems

Based on 150-kW fuel cell data and from the perspective of the anodic recirculation system (ARS) structure, this study added additional hydrogen recirculation components to meet the low-power hydrogen supply and recirculation of high-power stacks. Three different ARSs, namely, a parallel system, series system, and dual-ejector system, were established and integrated with the fuel cell. The ejector condensation model was established in this study because of the self-humidification function of high-power stacks. It was found that the parallel, series, and dual-ejector systems could achieve 5-100% power output of the stack and significantly decrease the power consumption of the hydrogen pump. In comparison to the series system, the parallel system exhibits a 15.8% improvement in stoichiometric ratio and a 14.8% enhancement in hydrogen recirculation ratio. The doubleejector system could reduce costs and increase the net output power of a proton-exchange membrane fuel cells (PEMFC) system by using an ejector instead of a hydrogen pump. In addition, the stoichiometric ratio of the dual-ejector system exhibits a 5.9% increase compared to that of the parallel system. Therefore, the dual-ejector system was the most promising.