Exploitation of thermochemical cycles based on solid oxide redox systems for thermochemical storage of solar heat. Part 5: Testing of porous ceramic honeycomb and foam cascades based on cobalt and manganese oxides for hybrid sensible/thermochemical heat s

Having previously identified the Co3O4/CoO and Mn2O3/Mn3O4 redox pairs as the most promising single-oxide systems for solar energy thermochemical storage, lab-scale (∅ 25 mm), Co3O4- and Mn2O3-coated, porous cordierite honeycombs and foams were prepared and tested with respect to their thermochemical characteristics in one- and two-oxides cascaded configurations employing redox oxide quantities in the range 15-150 g. For such Co3O4-loaded cascades thermochemical storage was clearly demonstrated as heat uptake/release at constant temperature under proper testing conditions. Besides, the additive effect of thermochemical on sensible storage within the same storage volume was visualized. The operating conditions of cascades including both Co3O4 and Mn2O3 were dictated by the redox behaviour of the Mn2O3/Mn3O4 pair. Under proper conditions, such two-oxides-cascades could undergo cyclic reduction-oxidation and operate in complementary temperature ranges during oxidation; however the thermal effects of only the CoO oxidation reaction could be materialized into temperature rise of the air stream exiting the cascade.