Metal hydride-based hydrogen storage devices are tested using AB(5) alloys, namely MmNi(4.6)Fe(0.4) and MmNi(4.6)Al(0.4.) Performance studies are carried out by varying the supply pressure, absorption temperature and overall heat transfer coefficient. At any given absorption temperature, hydrogen absorption rate and storage capacity are found to increase with supply pressure for both the alloys. At a supply pressure of 35 bar and a cold fluid temperature of 15 degrees C, MmNi(4.6)Fe(0.4) alloy stored about 1.6 wt%, while MmNi(4.6)Al(0.4) stored 1.3 wt%. Cold fluid temperature is found to have a significant effect on hydrogen storage capacity at lower supply pressures. The overall heat transfer coefficient has a negligible influence on the hydrogen storage capacities of both the alloys. However, higher values of overall heat transfer coefficients yield better rates of absorption and desorption. (c) 2005 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.