Density stabilized phase change material

The invention claims a is thermo generator phase-change material, comprising wherein the salt and an effective amount hydrous material is composed of the metal nitrate and metal nitrate of IA of a II or III, or a material is an wherein when of an phase, wherein liquid phase concentration and solid phase density of about same. The invention further claims a method for preparing such in the process of material containing same the phase-change material thermo generator.