This paper presents an investigation of the thermal effects during high pressure filling of a cryo-adsorptive hydrogen storage tank. The adsorbent is powdered activated carbon. A two-dimensional model is formulated, which describes hydrodynamics, heat transfer and adsorption phenomena in cylindrical tanks. Experiments with a tank containing about 10 kg of adsorbent were carried out to parameterize and validate the model. Good agreement between experiments and simulations could be obtained. Numerical results are then presented concerning filling processes. Two cooling concepts are investigated: a LN(2) cooling jacket and a recirculation system which uses the hydrogen itself as the cooling fluid. The results show that short filling times can only be achieved with the recirculation system. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.