Advances Made in Hydrogen Storage

Researchers have completed work on a crucial component for an experimental hydrogen storage system for cars, part of efforts to reduce pollution and the use of fossil fuels in transportation.

The system uses a fine metal powder to absorb hydrogen gas under high pressure. When the powder absorbs hydrogen, it becomes a "metal hydride," and the process is called "hydriding." By then decreasing the pressure in the vessel or warming the metal hydride, the hydrogen can be released to drive a fuel cell or engine.
A complication in perfecting the technology, however, is that the hydriding process generates heat, which hinders the absorption process and prevents the hydrogen storage vessel from being filled rapidly, says Issam Mudawar, a Purdue Univ. professor of mechanical engineering who leads the work with research assistant professor Timothée Pourpoint and doctoral student Milan Visaria.

Issam Mudawar, at left, a Purdue professor of mechanical engineering, and doctoral student Milan Visaria display their first- and second-generation heat exchangers, a crucial component of a hydrogen storage system for cars. The final design is a coil of stainless steel tubing that fits inside a hydrogen storage "pressure vessel" 4 inches in diameter. Purdue has filed a final patent on the heat exchanger. Photo by: Andrew Hancock

"If you're driving your hydrogen car, you can't wait an hour at the filling station," Mudawar says. "For this system to be practical, you have to be able to cool the hydride efficiently so that the storage vessel can be filled within five minutes with enough fuel to drive 300 miles." Read more.