Process for manufacture of a latent heat storage device

A process for the preparation of latent heat storage composites is provided. The process comprises the steps of preparation of an expanded graphite material with a bulk density between 5 and 200 grams/liter which is readily wetted by a liquid phase change material, preparation of a pre-compressed matrix or a packed bed of the expanded graphite material, and manufacture of a latent heat storage composite by infiltration of the matrix or a packed bed with a phase change material in a liquid state.