In order to study the effect of PCMs deterioration on their thermodynamic properties, some capsules were intentionally subjected to damage in laboratory. Placed between two glass slides, PCMs were sheared manually by moving the slides in order to simulate the shear forces of the mixing process. After, the damaged capsules were observed by Scanning Electron Micro- scopy (SEM ZEISS Supra 40 VP) in the same conditions than the non-damaged PCMs.