A 1-D model has been developed to evaluate various designs of metal hydride reactors with planar, cylindrical or spherical geometry. It simulates a cycling loop (absorption-desorption) focusing attention on the heat transfer inside the hydride bed, which is considered the ratelimiting factor. We have validated this model with experimental data collected on two reactors, respectively, containing 1 and 25g of LaNi5, the second being equipped with aluminium foam. The simulation program reproduces accurately our experimental results. The impact of the foam cell size has been studied. According to our model, the use of aluminium foam allows the reactor diameter to be increased by 7.5 times, without losing its performance. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.