Patent ID: 7037610

Claim:
A fuel cell system, comprising: a fuel cell having a hydrogen rich fuel inlet, an oxygen rich oxidant inlet, an anode tail gas outlet, and a cathode gas outlet; a source of hydrogen rich fuel connected to said hydrogen rich fuel inlet; a source of oxygen rich gas for said oxygen rich oxidant inlet; and at least one humidifier interposed between at least one of said sources and its associated inlet and having a reactant flow path interconnecting said one source and said associated inlet in heat exchange relation with an energy containing medium flow oath, and a source of aqueous material con- nected to said reactant flow path for introducing liquid aqueous material into said reactant flow oath to be vaporized therein; said energy containing medium flow path being connected to one of said outlets to receive a heated fluid therefrom to provide heat of vaporization to said liquid aqueous material by heat exchange between said flow paths wherein there are two said humidifiers having their reactant flow paths connected in series.