Power and hydrogen production from ammonia in a micro-thermophotovoltaic device integrated with a micro-reformer

Power and hydrogen (H2) production by burning and reforming ammonia (NH3) in a micro-TPV (microscale-thermophotovoltaic) device integrated with a micro-reformer is studied experimentally. A heat-recirculating micro-emitter with the cyclone and helical adapters that enhance the residence time of fed fuel-air mixtures and uniform burning burns H2-added NH3-air mixtures. A micro-reformer that converts NH3 to H2 using ruthenium as a catalyst surrounds the micro-emitter as a heat source. The micro-reformer is surrounded by a chamber, the inner and outer walls of which have installations of gallium antimonide photovoltaic cells and cooling fins. For the micro-reformer-integrated micro-TPV device the maximum overall efficiency of 8.1% with electrical power of 4.5 W and the maximum NH3 conversion rate of 96.0% with the H2 production rate of 22.6 W (based on lower heating value) are obtained, indicating that the overall efficiency is remarkably enhanced compared with 2.0% when the micro-TPV device operates alone. This supports the potential of improving the overall efficiency of a micro-TPV device through integrating it with a micro-reformer. Also, the feasibility of using NH3 as a carbon-free fuel for both burning and reforming in practical micro power and H2 generation devices has been demonstrated.