Status of energy conversion devices

Fuel cells have emerged onto the engineering stage. The most publicized system is, of course, the Gemini fuel cell. Possibly less well known are the "pilot plant" modules (5 KW) for accomplishing the indirect fuel cell oxidation of hydrocarbons. Hydrazine/air fuel cells are being adapted for military use as "special" power supplies. Test vehicles, e.g. lift tracks, have also been built with H2/O2and N2H4/O2systems. These efforts have heped define the basic engineering and research problems which must be solved in developing a "second generation" of fuel cell power plants.