Catalytic combustion of hydrogen—IV. Fabrication of prototype catalytic heaters and their operating properties

Two prototypes of catalytic heaters operating on hydrogen were fabricated and their performances were tested for combustion efficiency and temperature distribution over the catalyst surface. A heater in which hydrogen was mostly introduced from the bottom of a catalyst body exhibited substantial temperature uniformity and achieved a high combustion efficiency. The hydrogen fuelled catalytic heater offers an adjustable heat output ranging from 0 to 1.5 kcal cm^?2 h^?1 with Pt-impregnated nickel foam as a catalyst. The composite oxide of Co, Mn and Ag yielded slightly inferior results but sustained smooth hydrogen combustion. Detailed experiments were conducted for the investigation of changes in local combustion efficiency, local amount of air entrained from the ambience, and local surface temperature with the vertical position from the catalyst bottom.