A new way to have sunlight produce hydrogen has been perfected in a University of Delaware lab. The inventor, Erik Koepf, has designed a reactor that works at ultra-high temperatures and that uses zinc oxide and water to produce hydrogen at a potentially industrial scale without reforming fossil fuels, as it’s done in the industry nowadays.
The University’s fuel cell bus project is already using hydrogen for power. Ajay Prasad, professor of mechanical engineering and director of UD’s Center for Fuel Cell Research, and one of Koepf’s advisors, sees immediate use in his hydrogen generation technology.
“People have been trying for years to generate hydrogen renewably from sunlight, and Erik’s reactor takes us closer to that goal,” he says.
Erik’s reactor uses many disciplines including fluid mechanics, heat transfer, reaction kinetics and experimental design. It resembles a large cylinder made of layers of ultra-high temperature insulation and ceramic materials and has a quartz window on top, to withstand the heat of 10,000 suns that will power the reaction. The reactor’s geometry is conical.
The reactor is already installed in Switzerland at the Swiss Federal Institute of Technology in Zurich, where Kopf is now testing it in real life situations.
What actually happens inside the reactor
When zinc oxide powder is fed inside through 15 hoppers perched on top of the device, it will touch the preheated ceramic layer of the reactor and will get decomposed into pure zinc vapor. Water will then be reacted with the zinc vapor to produce hydrogen.
Basically, the chemical reaction looks like this:
2ZnO + heat → 2Zn + O2
2Zn + 2H2O → 2ZnO + 2H2
“Essentially, we take zinc oxide powder and thermochemically store the energy of the sun in it, then bottle it,” explained Koepf, whose work is funded mainly through the Federal Transit Administration, a part of the U.S. Department of Transportation. “Zinc in and of itself is a very valuable fuel that can be used in batteries and fuel cells, among other things, even if you don’t create hydrogen.”
As you can see from the chemical reaction above, after the it is done, the zinc oxide can be recycled again and again for countless cycles. Neat.
Koepf is very confident that his technology will one time power the world and will be applied at an industrial scale to produce hydrogen from natural elements like sunlight, zinc and water. What can be cleaner than this?