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AssigneeAalto University Foundation sr
InventorsAri Seppälä, Salla Puupponen
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The present invention relates to a cold-crystallizing material having high latent heat, and a method of using the present material for heat storing. The material of the invention comprises of a phase change material and an additive which is preferably a hydrophilic polymer matrix. Preferably, sugar alcohols, such as erythritol or D-mannitol, are used as the phase change material. The polymer of the invention is preferably cross-linked and ionic, i.e. a polyelectrolyte. PCM stores a high amount of heat energy while melting and releases the stored thermal energy by cold-crystallization. Compared to previously studied cold-crystallizing materials, the latent heat of the cold-crystallizing material of the invention is considerably higher, and cold-crystallization is more repeatable in successive melting-crystallization cycles. The material can be used for heat storing. Heat energy can be released from the material by a heat pulse on demand. The method is particularly suitable for long-term heat storing.
A composition, characterized in that it comprises at least two components, one of which is a supercooling phase change material and the other a component which is capable of stabilizing the phase change material when that material is in its supercooled state and when the composition is pre-cooled to a temperature which at least substantially corresponds to the glass transition point of the composition, or which is below it, the phase change material being capable of cold-crystallizing upon heating to above its cold-crystallization temperature.
The composition according to any of the preceding claims, characterized in that the composition is capable of vitrification when temperature is lowered to the glass transition point of the composition or below it.
The composition according to any of the preceding claims, characterized in that at least one of the components of the composition is polymeric.
The composition according to any of the preceding claims, characterized in that the phase change material comprises sugar alcohol, such as erythritol, mannitol, particularly D-mannitol, xylitol, arabitol, sorbitol or threitol, or any combination of two or more of these.
The composition according to any of the preceding claims, characterized in that the additive is a polymer.
A method of storing heat, characterized by using as a heat storage material a composition which comprises at least two components, one of which is a supercooling phase change material and the other a component which is capable of stabilizing the phase change material when that material is in supercooled state, wherein the phase change material is capable of cold-crystallizing when heating it to above the cold-crystallization temperature, wherein heat can be stored in the composition by bringing it into the supercooled state and by further cooling it to a temperature which at least substantially corresponds to the glass transition point of the composition or to a temperature below it, and correspondingly releasing heat from the composition which is in supercooled state by heating it above the cold-crystallization temperature.
Dependencies are inferred from the claim text.