A novel SOFC-MHR (metal hydride reactor)-Engine hybrid energy conversion system fueled with alternative fuels is proposed and modelled in this present study. The MHR is introduced into the hybrid system for H2 addition by waste heat recovery. The dynamic modelling is performed to investigate the transient response of the proposed hybrid energy conversion system. The results show that the SOFC has a relatively slow dynamic behavior while the engine has the fast dynamic behavior. Besides, the SOFC dominates the transient responses of the hybrid system because that the engine fuel directly comes from the FC off-gas. Therefore, it is found that the addition of H2 by MHR not only extends the system power output, but also improves the dynamics of the hybrid system due to the enhanced autonomy of the engine with fast transient response. When the H2 addition is χ=2.0, the hybrid system can quickly reach the stable power output within 5 s, indicating that the hybrid system presents superior dynamic behaviors and is promising for mobile applications.
Keywords SOFC, metal hydride reactor, engine, dynamic modelling