Abstract: A thermal storage system employing a fluid having a relatively high boiling point and capable of storage in separate phases, together with a substantial quantity of a chemically-compatible solid thermal storage medium.

Abstract: Heat is stored by melting a mixture of salts contained in compartments between an inner and an outer tube and radial copper fins which taper in radial outward direction. The molten salts solidify upon passage of relatively cold water through the inner tube, but formation of salt deposits on the fins is deferred so that liquid salt interfaces directly with the fins for an extended period of time during heat extraction.

Abstract: A quantity of aluminum is in heat exchange contact with a potassium loop and a steam/water loop. The potassium loop includes a solar energy collector and the solar-heated potassium melts the aluminum to store thermal energy as latent heat of fusion. The steam/water loop extracts steam at 1,000.degree. F. as long as at least some of the aluminum is in the molten state. The steam/water loop includes a steam power turbogenerator unit as user; the quantity of aluminum should suffice to yield, upon resolidification, sufficient heat to satisfy the energy demand of the unit during night time.