The use of metal hydrides as a cooling source for divers

This investigation has verified the feasibility of using the latent heats of absorption and desorption of hydrogen from various metal alloy pairs as a compact cooling source. These metal hydride pairs were found to provide a fully regenerative cooling capability which can be easily recharged between missions. A thermal analysis of combat swimmer operations indicated that approximately 100 watts of cooling capacity is required to offset the environmental heat load through a diver´s suit when swimming in water temperatures up to 38°C. A worst case assessment of initial absorption/desorption testing indicates that this cooling capacity is obtainable with less than 2.3 kilograms (5 pounds) of metal hydride. The proper selection of a high pressure metal hydride with a latent heat capacity during desorption of 36 kJ per gram mole of hydrogen could reduce this weight requirement to as little as 1.4 kilograms (3 pounds).