Patent ID: 8056341

Claim:
A method of storing heat energy in a body of graphite at an elevated temperature and recovering the heat energy therefrom, comprising the steps of: heating an inner region of the body of graphite when it is required to store the heat energy and recovering the stored heat energy, when it is required to be recovered, wherein the heating step comprises passing an electric current through a resistor disposed in a bore or well in the inner region of the body of graphite, so as to cause its temperature to rise, and wherein the resistor is electrically isolated from the body of graphite by means of a layer of electrically insulating material provided between a substantial portion of an inner surface of the bore or well and the resistor, so as to ensure that most of the electric current flows through a desired region or area or proportion of the internal surface of the bore or well located in a position within the body of solid graphite material and remote from the surface thereof.