Abstract: The invention concerns a thermal storage unit with a storage container having an internal space for holding a storage medium, the internal space including a solidification zone, in which the storage medium is located following a solidification process, and an expansion zone, in which the storage medium can expand during the melting process. In order to improve this thermal storage unit so that the mechanical loads are reduced, permitting the storage container to have a simpler, cheaper constructional design, it is proposed that the storage container wall surfaces in contact with the storage medium are made of a material which is not wetted by the storage medium.

Abstract: To improve a storage heater, which comprises a storage container with a wall region for the introduction of heat and a storage medium arranged in this storage container, in order to maximize the service life and to enable it to withstand a plurality of melting and solidifying processes, the wall region is provided with recesses opening out towards the storage medium, a wall surface of the region of the wall facing the storage medium is made of a material that is not wetted by the storage medium and the facing wall surfaces in the recesses are at a distance apart such that the storage medium does not enter them in the completely liquid state due to capillarity.