Fuel cells evaporatively cooled with water carried in passageways

A fuel cell power plant including a stack of fuel cells, each fuel cell comprising:

• an electrolyte having cathode and anode catalysts disposed on opposite sides thereof;
• a fuel reactant gas flow field plate having fuel reactant gas flow channels along a first surface thereof;
• an oxidant reactant gas flow field plate having oxidant reactant gas flow channels on a first surface thereof;
• at least one of said flow field plates being porous and hydrophilic;
• a water passageway disposed on a second surface of said at least one flow field plate which is opposite to said first surface thereof, said water passageway either being (a) dead-ended within the corresponding fuel cell or (b) vented, said water passageway consisting of either (c) a groove in said at least one plate or (d) a material contiguous with substantially all of said second surface, said material being conductive and hydrophilic and having an in-plane permeability to water,
• said fuel cell power plant further comprising:
• a source of fuel in fluid communication with said fuel reactant gas flow channels;
• a source of air in fluid communication with said oxidant reactant gas flow channels;
• and
• a condenser connected to a reactant gas exit of said at least one of said reactant gas flow field plates of each of said fuel cells, the condensate of said condenser in fluid communication with a proximal end of the water passageway in each of said fuel cells, whereby water migrates from said water passageways through said at least one hydrophilic, porous reactant gas flow field plates into the reactant gas channels thereof, and is evaporated by heat generated in said fuel cells to cool said fuel cells, the water therein being recycled through said condenser to return to said passageways.