The thermodynamic implications of conducting the solar combined ZnO-reduction and CH4-reforming under stoichiometric and non-stoichiometric conditions are examined. For a solar flux concentration ratio of 5000 and for a solar cavity-receiver operating at 1300 K, the solar thermal conversion efficiency is 55 percent for a stoichiometric molar ratio of ZnO and CH4, and decreases by 50 percent when using excess methane by a factor 10 over the stoichiometric molar amount. A technical solution for operating a gas-solid vortex-flow solar reactor under stoichiometric conditions was established by using a pulsed-feed of methane to carry out the particles of ZnO. Using this technique, nearly stoichiometric operation was demonstrated with a prototype reactor in a high-flux solar furnace, thereby opening up a means for efficient conversion of sunlight into chemical fuels.

Issue Section:
Technical Papers
Keywords:
solar absorber-convertors, solar energy concentrators, solar heating, furnaces, chemical energy conversion, fuel, vortices, thermodynamics, thermal analysis
Topics:
Cavities, Furnaces, Methane, Particulate matter, Solar energy, Temperature, Vortex flow, Fuels, Solar chemistry, Flow (Dynamics), Engineering prototypes
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