Determination of the minimum total weight is the main criterion in the design of a solid state hydrogen storage device for mobile or portable applications. The design should address additional requirements such as storage capacity, charge/discharge rates, space constraints, coolant temperature and hydrogen supply pressure. The typical metal hydride based storage device studied here consists of several filters to distribute hydrogen gas, and heat exchanger tubes to cool or heat the hydride bed based on whether hydrogen is absorbed or desorbed. The total weight of the system includes hydrogen storage material, heat exchanger tubes and associated heat transfer media, porous sintered filters and the cylindrical outer container. Systematic simulation of the heat and mass transfer during hydrogen sorption has been carried out for different feasible configurations. LaNi5 is used as the representative hydriding alloy in the device as its sorption performance is limited by heat transfer in the bed. The effect of geometric parameters on total system weight and charging time are plotted at specified operating conditions. These plots are used for the design of hydrogen storage devices with minimum system weight satisfying the imposed constraints. © 2009 by ASME.