Rechargeable cryogenic reactant storage and delivery system for fuel cell powered underwater vehicles

Abstract

A cryogenic liquid oxygen storage system for providing oxygen to a fuel cell powered underwater vehicle has been proven feasible through a research program with the Office of Naval Research. A system has been designed that meets the Navy specifications of storing 50 kg and delivering 0.1 to 100 g/min of oxygen in an unmanned underwater vehicle. The total system mass has been shown to be practical for an underwater vehicle and the oxidizer mass ratios have been shown to be significantly greater than alternative oxygen storage techniques such as chemical or high pressure gas. Waste heat from the fuel cell has been shown to be a plentiful and effective heat source for vaporizing and pre-heating cryogenically stored liquid oxygen. The pre-hazard analysis has identified the potential hazards and countermeasures have been developed that will enable the liquid oxygen system to meet the high safety standards set forth by the Navy. A system design tool has been created that integrates a cryogenic reactant storage and delivery system with fuel cell design models using Visual Basic Application language. The system design tool is useful for conducting sensitivity analyses of key design parameters on overall system performance.