Method for forming crystal nucleus in latent heat storage material and heat storage device

A heat storage device comprising:

• a latent heat storage material containing a solvent and a dissolved substance, the solvent containing water as a main ingredient, the latent heat storage material that retains latent heat when the latent heat storage material is in a supercooled state;
• a container containing the latent heat storage material in the supercooled state in which the latent heat storage material is maintained in a liquid state below a freezing point of the latent heat storage material while not becoming a solid;
• a heater adapted to heat part of the latent heat storage material in the supercooled state to separate out an anhydride of the dissolved substance;
• and
• a droplet feeder adapted to supply a droplet comprising water to the anhydride or a surface of the latent heat storage material on which the anhydride is located, to terminate the supercooled state of the latent heat storage material, and make the latent heat storage material dissipate heat, wherein
• the container has a space in contact with the surface of the latent heat storage material therein,
• the heater is adapted to heat the part of the latent heat storage material in the supercooled state by heating the space or the surface, to evaporate part of the solvent from the surface, and separate out the anhydride of the dissolved substance, and
• the droplet feeder includes a space cooler that cools the space to form the droplet by condensing moisture contained in the space.