Analyzing microcogeneration systems based on LT-PEMFC and HT-PEMFC by energy balances

This paper focuses on the performance analysis of microcogeneration systems based on the integration between a reforming unit (RFU), consisting of a natural gas steam reforming, and a power unit, based on the PEM fuel cell technology. The analysis has been carried out considering, as power unit, three different PEM fuel cells: a low temperature PEM fuel cell with Nafion™ membrane (LT-FC) operating at 67 °C, a high temperature PEM fuel cell with a membrane based on polybenzimidazole material doped with phosphoric acid (HT-FC1) operating at 160 °C, and a high temperature PEM fuel cell that uses aromatic polyether polymers/copolymers bearing pyridine units doped with phosphoric acid as electrolyte (HT-FC2) operating at 180 °C. udy has been conducted by using numerical models tuned by experimental data measured in test benches developed at University of Cassino. zing the power units able to provide a maximum electric power of 2.5 kW (this size allows to satisfy the electric and thermal energy demand of an Italian household), two designing criteria have been considered. s have shown that the integrated systems based on the HT-FCs are characterized by high electric efficiency (40%) and cogeneration efficiency (79%). er, the thermal power recovered decreases with the stacks operating temperature, thus the highest cogeneration efficiency (80%) is obtained by the microcogeneration system based on low temperature fuel cells. However, the availability of high temperature heat makes the HT-FC an attractive solution for the cogeneration/trigeneration systems development.