Heat storage device and method of using latent heat storage material

Abstract

A heat storage device includes a pair of electrodes; an alternating-current power source that applies an alternating-current voltage to the pair of electrodes; and a latent heat storage material that is disposed between the pair of electrodes, a supercooled state of the latent heat storage material being maintained by the alternating-current voltage.

What is claimed is: 
     
         1 . A heat storage device comprising:
 a pair of electrodes;   an alternating-current power source that applies an alternating-current voltage to the pair of electrodes; and   a latent heat storage material that is disposed between the pair of electrodes, the latent heat storage material being maintained in a supercooled state by the alternating-current voltage.   
     
     
         2 . The heat storage device according to  claim 1 , wherein each of the pair of electrodes includes an electrode main body having electrical conductivity and an insulation layer coating a surface of the electrode main body. 
     
     
         3 . The heat storage device according to  claim 2 , wherein the alternating-current voltage is in a range of 2 V to 35 V. 
     
     
         4 . The heat storage device according to  claim 1 , wherein a frequency of the alternating-current voltage is in a range of 10 kHz to 100 kHz. 
     
     
         5 . The heat storage device according to  claim 1 , wherein the alternating-current power source applies the alternating-current voltage to the pair of electrodes to maintain the supercooled state of the latent heat storage material, and then further stops application of the alternating-current voltage to release the supercooled state of the latent heat storage material. 
     
     
         6 . The heat storage device according to  claim 1 , further comprising a temperature sensor that directly or indirectly detects a temperature of the latent heat storage material, wherein
 the alternating-current power source includes a variable frequency power source, and   a frequency of the alternating-current voltage is changed in accordance with the detected temperature.   
     
     
         7 . The heat storage device according to  claim 1 , further comprising a temperature sensor that directly or indirectly detects a temperature of the latent heat storage material, wherein
 the alternating-current power source includes a variable voltage power source, and   the alternating-current voltage is changed in accordance with the detected temperature.   
     
     
         8 . The heat storage device according to  claim 1 , further comprising a temperature sensor that directly or indirectly detects a temperature of the latent heat storage material, wherein
 the alternating-current power source selects whether or not the alternating-current voltage is applied to the pair of electrodes in accordance with the detected temperature.   
     
     
         9 . The heat storage device according to  claim 8 , wherein in a case where the temperature of the latent heat storage material is higher than a freezing point of the latent heat storage material, the alternating-current power source does not apply the alternating-current voltage to the pair of electrodes, and in a case where the temperature of the latent heat storage material is equal to or lower than the freezing point of the latent heat storage material, the alternating-current power source applies the alternating-current voltage to the pair of electrodes. 
     
     
         10 . The heat storage device according to  claim 1 , wherein after heat is applied to the latent heat storage material from outside of the heat storage device, the alternating-current power source applies the alternating-current voltage to the pair of electrodes to maintain the supercooled state of the latent heat storage material. 
     
     
         11 . The heat storage device according to  claim 1 , wherein the latent heat storage material contains a hydrated salt or sugar alcohol. 
     
     
         12 . The heat storage device according to  claim 1 , wherein the latent heat storage material is sodium acetate trihydrate. 
     
     
         13 . A method of using a latent heat storage material, comprising:
 applying heat to a latent heat storage material disposed between a pair of electrodes to melt the latent heat storage material;   after the melted latent heat storage material enters a supercooled state, applying an alternating-current voltage to the pair of electrodes to maintain the supercooled state of the latent heat storage material while the latent heat storage material retains the heat; and   stopping application of the alternating-current voltage to release the supercooled state of the latent heat storage material, allowing the heat to be released from the latent heat storage material.