Abstract: A polyphase composition for the storage of heat or cold utilizing the latent heat of fusion of a salt hydrate continuous phase intimately intermixed with a hydrated hydraulic cement continuous phase and wherein said continuous phases are optionally in contact with a discontinuous crystalline phase comprising a nucleating component and wherein the composition is enveloped, contained, or packaged within a vapor impermeable material.

Abstract: A thermal storage structure and process for making the same comprising a base material of a substantially open cell structure, with the pores interconnected and open to the surface. The open cell structure may be a volcanic rock or alternatively may be a synthetically made structure such as foamed glass, foamed concrete or foamed metal. The open cell material is completely saturated with a latent heat storage component such as a salt-hydrate or eutectic salts. In the process of making the latent heat storage structure, the latent heat storage component is melted in a container and the open cell structure is placed therein, whereupon the melt is spontaneously imbibed by the structure, replacing the air in the open cell structure with the liquid latent heat storage component. The structure, after cooling, is packaged or encapsulated with a vapor impermeable material.