NOVELTY - A fuel cell (1) having anode (3) and cathode (4) separated from one another and evaporator cooler to adjust moisture and temperature of fuel and oxidant (9) for the fuel cell, has heat exchanger plate with dry and wet sides impervious to water, fuel, and oxidant and forms parts of interconnected dry (7) and wet (8) working channels.    USE - Used as fuel cell.    ADVANTAGE - The invention has increased operation efficiency.    DETAILED DESCRIPTION - The fuel cell comprises heat exchanger plate with dry and wet sides impervious to water, fuel, and oxidant and forms parts of interconnected dry and wet working channels with the dry working channel being on the dry side and the wet working channel being on the wet side and further forms part of product channel(s) (6) separated from the dry and wet working channels. The fuel passes through the dry working channel and then the wet working channel in which the fuel picks up moisture vapor from water evaporation that cools the heat exchanger plate and the cooled plate cooling the fuel passing through the dry working channel. The oxidant passes through the product channel to be cooled by the plate and being directed to the cathode where water is produced and some of this water is directed to wet the wet side and the wet working channel.    An INDEPENDENT CLAIM is also included for a method to adjust moisture and temperature of fuel and oxidant in the fuel cell comprising positioning an anode separator with the heat exchanger plate to form fuel passageway between the anode and the second side of the plate; wetting the second side of the plate with water; passing fuel first by the dry side of the plate of the anode separator; passing the fuel by the wet side of the plate of the anode separator; adding moisture to the fuel in the fuel passageway; positioning a cathode separator with the heat exchanger plate; wetting the second side of the plate of the cathode separator with water; passing oxidant first by the dry side of the plate of the cathode separator to cool the oxidant; passing the oxidant by the wet side of the plate of the cathode separator to evaporate water to cool the plate of the cathode separator plate thus cooling the oxidant on its dry side; cooling the cathode with the cool oxidant; and using water produced at the cathode to wet the wet sides of the respective heat exchanger plates of the anode and cathode separators.    DESCRIPTION OF DRAWING(S) - The figure is a schematic representation of a fuel cell system with evaporative cooling methods for humidifying and adjusting the temperature of reactant streams.    Fuel cell (1)    Electrolyte membrane (2)    Anode (3)    Cathode (4)    Product channel (6)    dry working channel (7)    Wet working channel (8)    Oxidant (9)    Hydrogen (11)    Water distribution system (12)    Barriers (42)