Heat and mass transfer performances of the metal hydride beds have been predicted by solving a set of volume-averaged equations numerically both for the gas(hydrogen) and solid(metal hydride) phases. Time variations of temperature and hydrogen concentration ratio distributions have been obtained. In order to confirm the validity of the present method, an experimental result with a one-dimensional hydride beds was tested ; the calculated result agrees with the experimental one reasonably, and also from that, the rate of the hydrogen generation for the metal was dedueced. Then a series of calculation have been performed internally cooled, cylindrical-shaped beds with a metal(aluminum) fins imbedded in it. Temperature and velocity of the coolant, hydrogen pressure at the gas inlet, and the fin spacing were taken as the parameters. The rate of hydrogen absorption increases with the higher velocity and the lower temperature of the coolant, and with the decrease of the fin spacing. Increasing of the hydrogen pressure at the gas inlet also promotes the rate of absorption though the increasing of the absorption rate gradually slows down. However, the amount of the hydrogen storage per unit volume of the bed decreases with increasing of the fin spacing, which may compensate the advantage of higher absorption rate ; therefore there should be an optimum fin spacing in practical applications.
