The polymer electrolyte membrane fuel cell is being proposed for a number of power
generation systems. With regard to replacing conventional technologies, they offer many
advantages including quiet operation with low emissions. However, the key issue for the
success of fuel cell system will be a superior operational efficiency. The associated subsystems
for controlling fuel cell stack thermal and water management contribute
significantly to the reduction in stack weight and volume and increase the associated
operational parasitic losses. In this thesis a novel fuel cell operational method has been
proposed which utilises a combined humidification and cooling mechanism based on the
direct injection of liquid water to the cathode flow-field. Several analyses were performed
to investigate critical issues for the workable concept of such an EC, or evaporatively
cooled, fuel cell system. [Continues.