Fuel cells can deliver clean, reliable, and uninterrupted power nearly 100 percent of the time. Fuel cells offer the advantage of efficiency by converting chemical energy directly to electricity. They have no moving parts, thereby eliminating failures associated with pumps, blowers, heat exchangers, and other systems. All fuel cells, particularly high-temperature fuel cells, require spent fuel/waste heat recovery subsystems, and low-temperature fuel cells require fuel reforming subsystems that lower the efficiency of the entire system.
Although solid-oxide fuel cells (SOFCs) provide durability and economic advantages over liquid electrolytic fuel cells, SOFCs at present typically operate at high temperatures, and therefore require a means for disposing of the released heat. As such, they may become bulky, noisy, and comprise several moving parts that require frequent maintenance. Systems that combine SOFCs and molten carbon fuel cell characteristics contain a liquid, which gives rise to corrosion and electrolyte loss.
This invention provides a fully integrated hybrid system by using two fuel cells in tandem. The SOFC is used to electro-chemically introduce oxygen into a fuel stream to supercharge the fuel stream with oxygen for more efficient thermodynamic conversion by a low-temperature fuel cell.
The tandem system would combine the advantages of both high-temperature and low-temperature fuel cells without the disadvantages of each. In addition, the tandem system would be modular and scalable for use in the transportation and propulsion power sectors, and should further be adaptable to hydrogen co-generation in industrial settings.