Abstract: The invention relates to a heterogeneous structure for energy accumulation-dissipation (10), the structure being constituted by a porous capillary solid matrix (11) of open capillary porosity and of controlled topology, with capillary passages (12) of varying section and/or mutually interconnected to form labyrinths, and by a liquid (13) surrounding the porous capillary matrix and defining a liquid/solid separation surface, with the matrix (11) being lyophobic relative to said liquid. The area of the separation surface then varies isothermally and reversibly as a function of the external pressure to which the heterogeneous structure (10) is subjected.