Optimization and Demonstration of a Solid Oxide Regenerative Fuel Cell System

摘要

Single cell solid oxide regenerative fuel cells (SORFCs) have been demonstrated for over 1000 hours of operation at degradation rates as low as 0.5% per thousand hours for current densities as high as 300mA/cm{sup 2}. Efficiency levels (fuel cell power out vs. electrolysis power in) have been demonstrated in excess of 80% at 100mA/cm{sup 2}. All testing has been performed with metallic based interconnects and non-noble metal electrodes in order to limit fabrication costs for commercial considerations. The SORFC cell technology will be scaled up to a 1kW sized stack which will be demonstrated in Year 2 of the program. A self contained SORFC system requires efficient thermal management in order to maintain operating temperatures during exothermic and endothermic operational modes. The use of LiF as a phase change material (PCM) was selected as the optimum thermal storage medium by virtue of its superior thermal energy density by volume. Thermal storage experiments were performed using LiF and a simulated SORFC stack. The thermal storage concept was deemed to be technically viable for larger well insulated systems, although it would not enable a high efficiency thermally self-sufficient SORFC system at the 1 kW level.