A novel microscale combustor-heat exchanger (CHX) for hydrogen storage applications is presented in this dissertation. The design of the CHX is motivated by its application to two particular systems for automotive use- those that utilize metal hydrides (MH) and cryo-adsorbents (CA) to store hydrogen. Thermal energy needs to be supplied to the MH bed to raise its temperature to 170 oC in order to desorb hydrogen for use in a fuel cell. On the other hand, in a CA system, hydrogen gas that exits the storage tank needs to be heated to a minimum temperature of-40 oC prior to entering the fuel cell. During cold start conditions, heat exchange with ambient air or with the fuel cell coolant is insufficient to provide this minimum temperature, thereby requiring an additional source of thermal energy. For both storage systems, the required thermal energy can be provided by oxidizing a small amount of hydrogen and transferring the heat from combustion to the working fluid, which is an oil in a MH system and hydrogen in a CA system. The CHX presented herein is a compact and highly efficient way of providing the required thermal energy rate. The µCHX is comprised of repeating unit cells that each perform identical unit operations, namely (a) catalytic combustion of a hydrogen-air mixture, (b) transfer of produced thermal

Effect of wall thermal conductivity on the performance of Swiss roll combustors using ammonia pretreated Pt catalyst for catalytic reaction