SBIR-STTR Award

A program for the development of a hydrogen generator for use with pem fuel cells in UUV applications is proposed. Hydrogen is generated by reacting alkali and alkali-earth metal hydrides with water. Pure hydrogen and alkali-alkali earth metal oxides or hydroxides are formed. Energy densities may exceed lkwhr/lb of reactants. Generation is not affected by vehicle position or motion. The proposed development addresses: 1. The problem of uniformity and completeness of reactant utilization. 2. Control of hydrogen generation rate (load responsive generation). 3. Volume expansion of solid reactants. 4. Dissipation of reaction heat. The solid hydride reactant is distributed for this purpose in a cartridge of corrugated and perporated sheet metal. Strands of wicking material are placed in contact of the hydride and wicking pads placed on either side of the assembly. The cartridge is placed in a pressure vessel. Water is metered to the vessel and dlstributed rapidly by wicking throughout the cartridge generating hydrogen as required by the load (load responsive). In addition, water is vaporized by the heat generated in the reaction and condensed on the reactor walls or cooling coils before being recycled by wicking. The volume expansion taking place during the conversion is taken up by the corrugated sheet metal structure. The hydrogen generator to be developed under the proposed program, if combined with pem fuel cells for power generation, offers energy densmes substantially superior to batterbs in UUVand hand or man portable applications.

A program for the development of a hydrogen generator for use with PEM fuel cells in UUV applications is proposed. Pressurized hydrogen is generated by reacting alkali-metal hydrides with water to be derived from the PEM fuel cell. Energy densities approach 1 Kw-hr/lb. The proposed effort is concerned with the design, fabrication, and evaluation of a generator with 50 Kw-hr. capacity capable of sustaining PEM cell operation at the 3 KW output level. The hydrogen generator is gas cooled, unaffected by vehicle position and motion and serves as a precursor for a generator to be developed for the 21" vessel. Furthermore, under the proposed effort, subsystem design and test data are being developed, which are aimed at maximizing space utilization. This information is incorporated in the design of a generator with 500 Kw-hr. capacity to be used in the 44" vessel. Anticipated

Benefits:
The hydrogen generator to be developed under the proposed program, if combined with PEM fuel cells for power generation, offers energy densities substantially superior to batteries in UUV, man portable, or standby applications.