Thermal Behavior of an Air Cooled PEM Fuel Cell Stack

Abstract

Thermal behavior of a 1 kW, air cooled PEM fuel cell stack was analyzed and simulated. Operation of the stack under various scenarios was simulated such as start-up from room temperature, steady state at full and half load and sudden changes of load (from full to half load and reverse), under constant or variable flow rate of the cooling air. In variable power load operation, the stack temperature is not constant. One interesting finding of this analysis is that liquid water occurs at the outlet whenever the stack temperature falls below 60{degree sign}C, although the nominal operating conditions were selected such that there is no liquid water at the outlet at steady state operation. The results also indicate that this particular stack has insufficient heat exchange area with cooling air resulting in relatively large cooling air flow rates and low temperatures.