The present invention concerns an area-measured material (sheet material) (10) comprising a continuous surface portion (frames) and a void content (12) of at least 25%, preferably 50% or more in relation to the total area covered by the area-measured material (sheet material). The continuous surface portion frames consists totally or partially of hollow structures, tubes or capillaries (13) tailored to transport a fluid medium. These hollow structures are docked to at least one collector (11). Both textile sheet material with hollow fibres, sheets, films, panels or composite structures of sheets, films or panels with hollow structures as tubes or capillaries can be used as well as grids with elongated ribbon-like elements. These area-measured materials (sheet materials) can be used for instance to absorb and/or store and/or transport and/or to discharge energy, in particular, if the “energy density” is low. The absorbed energy can be converted into any other kind of energy.