Degradation of membranes in fuel cells (10) due to dehydration by relatively dry incoming reactant gases is avoided through the use of a heater/humidifier (36) and/or (40) in the incoming reactant streams, (12,14). At least one of the humidifiers (36,40) i...

A body (6) of a heat exchanger is provided with a plurality of heat receiving fluid passages (10A) having openings directed upward. A header (1) is fitted to the top of the body (6). The header (1) has a bottom plate (1B) having a plurality of through hole...