In a fuel cell system, sufficient water to supply the consumption needs of the system, particularly by the system humidifiers and fuel processor, can be obtained from the exhaust of the fuel cell stack without the use of a condenser, by controlling the operating temperature of the fuel cell stack. The operating temperature can be controlled, for example, using a controller that monitors water level in the process water reservoir and increases or decreases the operating temperature through control of the fuel cell cooling system to maintain the water level within a predetermined range representative of neutral water balance in the system.

A two-stage evaporator unit converts a liquid reactant mass flow adjustable as a function of a load presetting into a gaseous reactant mass flow. The liquid reactant mass flow is at least partially evaporated in the first stage by a heat-exchange medium, and, if appropriate is completely evaporated and subsequently superheated in the second stage. The evaporator unit is formed by the alternating stacking one on the other of foils having heat-exchange channels and by foils having reaction channels that, in each case, have at least one first and one second stage integrated in one foil. The first stage is configured as a channel with a minimized cross-sectional area which is directly connected to the inflow conduit. The first stage is operated at high coefficients of heat transmission. The total cross-section of the reaction channels in the second stage increases in the flow direction.

A heating system for a vehicle includes a reformer arrangement for producing hydrogen from a hydrocarbon/mixed material mixture, a burner arrangement for reception of hydrogen produced in the reformer arrangement and combustion thereof, and a heat exchanger arrangement for transferring combustion heat produced in the burner arrangement to a heating medium.

A mass and heat recovery system for a fuel cell power plant includes at least one fuel cell for producing electrical energy, hydrocarbon fuel processing components for producing a hydrogen rich reducing fluid for the fuel cell, and a direct mass and heat transfer device for recovering mass and heat such as water vapor leaving the plant. The fuel processing components include an auxiliary burner that provides heat to generate steam and a reformer that receives the steam mixed with a hydrocarbon fuel along with a small amount of air and converts the mixture to a hydrogen rich stream appropriate for supplying hydrogen to the anode electrode. The direct mass and heat transfer device passes a process oxidant stream upstream of the plant in mass transfer relationship with a plant exhaust stream that includes both a cathode exhaust stream and an anode exhaust stream wherein the anode exhaust stream has first been burned in the auxiliary burner so that mass and heat such as water vapor in the plant exhaust stream transfer directly through a mass transfer medium of the device to the process oxidant stream entering the plant. The device includes a separator housing for supporting the transfer medium and for preventing bulk mixing of the streams. An exemplary transfer medium such as a liquid water portion of a water saturated polyflourosulfonic ionomer selectively sorbs a fluid substance consisting of polar molecules such as water molecules from a fluid stream containing polar and non-polar molecules.

A power supply includes a fuel cell stack, a thermoelectric module and a burner module. The fuel cell stack generates a primary source of electricity and secondary source of heat. The thermoelectric module generates a secondary source of electricity. The burner module is juxtaposed to the fuel cell stack and the thermoelectric module, to provide primary heat to the system and to generate a temperature differential across the thermoelectric module, and to pre-heat a fuel and an oxidant for the fuel cell stack. The burner module is regulated to maintain a given system temperature, or when needed by the thermoelectric generator for secondary power generation.