Nuvera Fuel Cells, Inc.

Christopher J O'Brien

Lawrence G Clawson

Mark R Hagan

A hydrogen fuel cell power system having improved efficiency comprises a fuel cell, a source of hydrogen gas, a compressor for creating a pressurized air stream, and a liquid supply which is heated by waste heat form the power system and evaporates into the pressurized air stream to produce a pressurized air and steam mixture. The pressurized air/steam mixture, which is preferably used as the oxidant in the fuel cell, is combusted with fuel in a burner to produce a high-temperature steam-laden exhaust stream. The high-temperature steam-laden exhaust stream drives an expander to produce a power output, and a power take-off from the expander uses the expander power to, for instance, drive an electrical generator, or drive other system components. The evaporation of liquid can take place external to the fuel cell, or can take place directly within the fuel cell, preferably using a cooling liquid that is directly injected into the fuel cell. The fuel cell power system advantageously uses the low-temperature waste heat of the fuel cell to evaporate liquid into the pressurized air, resulting in a steam/air mixture having a relatively large expansion potential. The systems and related methods of the invention are applicable to a wide range of fuel cell power systems, including a 'pure' or 'non-hybrid' fuel cell power system, powered by hydrogen from either an external source, such as a hydrogen storage tank, or from &#x201c;direct&#x201d; reforming of a fuel at the anode. The invention is also applicable to integrated or &#x201c;hybridized&#x201d; fuel cell power systems which contain a local fuel reformer. In these systems, the fuel cell is powered by hydrogen-containing reformate generated by the reformer.

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Watertown, MA, United States of America

Christopher J O'Brien