Part one: a novel model of HTPEM-based micro-combined heat and power fuel cell system

Fuel cell-based combined heat and power (CHP) systems have received increasing attention during the last decade. This is mainly due to the high efficiencies obtainable on even a small-scale system basis. The current paper focuses on the development of a complete model of a system consisting of the high-temperature proton exchange membrane (HTPEM) fuel cell stack based on PBI membranes, steam-reforming reactor, burner, heat reservoir and other auxiliary equipment included in a typical reforming-based fuel cell system. The model is implemented in the MatlabsSimulink environment enabling both static system integration as well as dynamical control strategies to be evaluated. All results of the submodels correspond well with experimental results obtained. Additionally, a novel system integration of an HTPEM fuel cell and a steam reforming-based fuel processing unit is presented. The total energy utilization efficiency of the system modeled is as high as 902100%LHV depending on the operating point chosen, whereas the electrical efficiency can be up to 45%LHV. This is more than 30% better than the best low-temperature PEM-based systems demonstrated today.