High temperature thermochemical hydrogen cycles for solar heat sources

Some of the criteria required for high temperature thermochemical hydrogen cycles to couple efficiently with solar heat sources are defined. Some of the experimentally validated cycles that have been developed over the years in terms of these criteria are examined and potential cycles that are being considered for the higher temperatures potentially available from solar concentrators are discussed. Cycles discussed include oxide-sulfate cycles, halide hydrolysis cycles, direct decomposition of H/sub 2/O and CO/sub 2/, oxide cycles, and sulfuric acid-metal sulfate cycles. (WHK