A water and thermal management model for a Ballard PEM fuel cell stack was developed to investigate its performance. A general calculation methodology was developed to implement this model. Knowing a set of gas feeding conditions (i.e., pressure, temperature, flow rate) and stack physical conditions (i.e., channel geometry, heat transfer coefficients, operating current), the model could provide information regarding the reaction products (i.e., water and heat), stack power, stack temperature, and system efficiency, thereby assisting the designer in achieving the best thermal and water management. Furthermore, if the stack undergoes a perturbation, such as the initial start-up, quick change in current, or a shutdown, the model could predict the dynamic information regarding stack temperature, cell voltage, and power as a function of time. (c) 2005 Elsevier B.V. All rights reserved.