Putting unused hydrogen back into the system. . .

By Gary S. Vasilash

Although there is a concern regarding fuel efficiency when it comes to petroleum-powered vehicles, when using alternative forms of “fuel,” like hydrogen, making sure that the most is made of it is arguably even more important—after all, the price of hydrogen in the U.S. is over $30 per kilogram, with a kilogram being approximately equivalent to a gallon of gasoline.

To that end, ZF has developed a hydrogen recirculation blower.

Essentially, it recirculates unused hydrogen back into the fuel cell by using a an electric motor that can operate at speeds up to 100,000 rpm to essentially blow the hydrogen back into the stack.

Because at the outgoing side of the fuel cell stack there is water (that’s the emissions from a hydrogen fuel cell: air contains oxygen, and as you recall from high school chemistry, hydrogen + oxygen form H₂O) there is a water separator that not only keeps things from getting all wet, but serves as a coolant.

The recirculator has been engineered for use in commercial vehicles and will undoubtedly find application in Europe, where more fuel cell electric trucks are being introduced.

The price of hydrogen in Europe is competitive with the cost of fuels for thermal engines, and the amount of time it takes to refuel a hydrogen vehicle is approximately that of a liquid-fueled truck (compared to the l-o-n-g time to recharge a battery electric truck), so it makes sense that fleet operators would be interested in hydrogen as they lower their carbon emissions.

Just imagine how important this would be in places where hydrogen is exceedingly expensive compared to other fuels.