Heat management in polymer electrolyte membrane fuel cells (PEMFCs) plays a vital role in stack performance and durability, and overall system efficiency A computational model assembled by the authors has been used to study the heat generated and distributed in single cell and two cell PEMFC stacks with a focus on temperature variation on the external surfaces of the stack under different heat loads An infrared thermal imaging camera was used to experimentally validate the results using a polymer fuel cell stack assembled in the authors laboratory The model and the assembled stack were run under various operating conditions of gas flow rate temperature and heat load In general good agreement with an average variance of temperature less than 5% was achieved between the model and the experiment Results showed that the temperature variation on the outer faces of the stacks is influenced not only by convective heat transfer through the gas flow channels but also by the heat lost via natural convection and conductive heat transfer between different components Furthermore results obtained from the two cell stack showed that by increasing the number of cells from one to two the temperature variation in the stack increases and therefore thermal management becomes increasingly significant (C) 2010 Professor T Nejat Veziroglu Published by Elsevier Ltd All rights reserved