Exploitation of thermochemical cycles based on solid oxide redox systems for thermochemical storage of solar heat. Part 3: Cobalt oxide monolithic porous structures as integrated thermochemical reactors/heat exchangers

Dilatometry experiments under the same temperature-programmed conditions with the TGA ones revealed that during redox cycling, “chemically”-induced stresses are developed due to the expansion/contraction of the cobalt oxide lattice during oxygen release/uptake respectively. These stresses are superimposed to “thermal-only” ones due to temperature cycling and under certain circumstances can lead to structure deformation and fracture. In this respect “open” porous structures like the particular foams proposed and tested in this work have an advantage since their large void space can reversibly accommodate and “buffer” the large volume expansion much better.