Wireless Reliable Multicast

A portable hydrogen source for proton exchange membrane fuel cells (PEMFCs) isproposed. The design utilizes both an exothermic reaction between ammonia (NH3)and aluminum hydride (AlH3) and ammonia decomposition. This process isinitiated by catalytic decomposition of a small amount of NH3 at about 450 ¿Ctemperature and is subsequently self-sustained to provide hydrogen to the fuelcell on demand. Expected hydrogen yield is 1.7 liters per gram of reactants,representing 2.6 Wh per gram of reacting materials, computed by Army guidelines.An integrated hydrogen source package producing 300 Wh to 1000 Wh will have apackaged energy density of between 1.1 Wh and 1.6 Wh per gram of system weight.The hydrogen source will include an ammonia tank, reactor with a heating elementand AlH3 block, a control block, and tubing and passive valve arrangement. Thispackage will also include a special filter, which can absorb 20% of its mass inimpurities such as NH3, and reduce them to less than 1 ppm. The proposed effortwill include a study of reaction kinetics, optimum reactor design for heatutilization, component ratio optimization, a control system for on-demandhydrogen, and a commercial prototype with 1 kWh energy capacity.