Zinc Oxide Solar Reactor could be a Renewable Source of Hydrogen

05 Apr 2012

Solar Zinc

Erik Koepf, a University of Delaware doctoral candidate in mechanical engineering, has designed a novel reactor that employs highly concentrated sunlight and zinc oxide powder to produce solar hydrogen.

The reactor, which resembles a large cylinder, is comprised of layers of advanced, ultra-high temperature insulation and ceramic materials. It measures roughly 2 feet by 3 feet and weighs a hefty 1,750 pounds.

The conical geometry of the reactor’ design uses gravity to feed zinc oxide powder (the reactant) into the system through 15 hoppers perched on top of the device using special gears and a custom built control assembly Koepf developed at UD. Cooling blocks embedded in the structure keep the motors, a quartz window and the aperture ring, where the sunlight enters, cool.

“The idea is to create a small, well-insulated cavity and subject it to highly concentrated sunlight from above,” explained Koepf.

Koepf has been testing the main control systems for his reactor in Spencer Laboratory for months. The missing ingredient, however, has been sunlight. Beginning April 5, he will spend six weeks testing the prototype’s effectiveness for the first time at the Swiss Federal Institute of Technology in Zurich.

During testing, light concentrated to simulate the energy of 10,000 suns will be focused down into the reactor, sending the temperature within soaring to over 3,000 degrees Fahrenheit, nearly one-third the temperature of the sun’s surface. Once hot, the hoppers will feed zinc oxide powder (a benign substance resembling baking soda) onto the ceramic layer, causing a reaction that decomposes the powder into pure zinc vapor. In a subsequent step, the zinc will be reacted with water to produce solar hydrogen.

“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.

One interesting feature of the reactor is that, in theory, the zinc oxide byproduct created during the reaction will be re-usable, making the project self-sustaining.

Source: PhysOrg.com

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