Zusammensetzung zur Wärmespeicherung

A heat storage composition comprises sodium sulfate decahydrate as main component, a supercooling inhibitor, and as a solid-liquid separation inhibitor, hydraulic calcium sulfate and/or calcium sulfate dihydrate in an amount of 2-15% by weight based on the whole weight of the composition, whereby the solid-liquid separation, i.e. the sedimentation of the anhydrous sodium sulfate during the phase transition, is effectively prevented and the long-term stability is improved. The long-term stability of the composition can be more improved by addition of a silica series of thickener.