A latent heat storage material is in the form of a composite material
formed of a phase-change material to store latent heat and graphite
flakes incorporated therein to improve thermal conductivity. The graphite
flakes are distinguished by a high aspect ratio and a high anisotropy of
thermal conductivity. The volume content of graphite flakes in the latent
heat storage material is between 10 and 40%. The composite material can
be obtained by mixing the components or infiltrating a bed containing
graphite flakes with a liquid phase-change material. The graphite flakes
are preferably aligned during mixing with the phase-change material by
shaking or tamping, etc., so that the thermal conductivity in the
direction that is advantageous for the individual application is
maximized. A latent heat storage unit containing the material and
processes for producing the material and the unit and processes for using
the material, are also provided.