Heat storage system

Abstract

A heat storage system is provided that is capable of being manufactured at lower cost and has higher heat transmission efficiency. A heat storage system includes a heat storage material having a higher specific gravity in a solid phase than in a liquid phase, a heat storage tank for containing the heat storage material, a cooling side heat exchanger arranged at an upper section inside the heat storage tank and for cooling the heat storage material, a heating side heat exchanger arranged at a lower section inside the heat storage tank and for heating the heat storage material, and a wall surface heater for heating a side wall of the heat storage tank.

What is claimed is: 
     
         1 . A heat storage system, comprising:
 a heat storage material having a higher specific gravity in a solid phase than in a liquid phase;   a heat storage tank for containing the heat storage material;   a cooling side heat exchanger arranged at an upper section inside the heat storage tank and for cooling the heat storage material;   a heating side heat exchanger arranged at a lower section inside the heat storage tank and for heating the heat storage material; and   a wall surface heater for heating a side wall of the heat storage tank.   
     
     
         2 . The heat storage system according to  claim 1 , wherein a mixed salt of an amorphous composition is used as the heat storage material, the mixed salt becoming a solid-liquid coexisting state at a minimum temperature of the heat storage T min . 
     
     
         3 . The heat storage system according to  claim 1 , further comprising:
 an auxiliary heater provided at a lower section inside the heat storage tank and for forming a fluid passage for allowing the heat storage material, which becomes the liquid phase from the solid phase due to heating by the heating side heat exchanger, to escape upwardly.   
     
     
         4 . The heat storage system according to  claim 1 , wherein the heating side heat exchanger is arranged at a bottom surface of the heat storage tank, and formed by a plate like heat exchanger inside which a flow channel is arranged for flowing a heat medium for heating. 
     
     
         5 . The heat storage system according to  claim 1 , wherein the cooling side heat exchanger has a cooling surface made of glass. 
     
     
         6 . The heat storage system according to  claim 1 , further comprising:
 a solid phase exfoliation unit for allowing the heat storage material, which is cooled by the cooling side heat exchanger and becomes the solid phase, to exfoliate from the cooling side heat exchanger.   
     
     
         7 . The heat storage system according to  claim 6 , wherein the solid phase exfoliation unit is provided with a circulating pump for suctioning the heat storage material in the liquid phase inside the heat storage tank, discharging the suctioned heat storage material into the heat storage tank, and flowing the heat storage material so as to allow the heat storage material, which becomes the solid phase, to exfoliate from the cooling side heat exchanger. 
     
     
         8 . The heat storage system according to  claim 6 , wherein the solid phase exfoliation unit is provided with a bubble generation device for generating bubble below the cooling side heat exchanger inside the heat storage tank, and allowing the heat storage material, which becomes the solid phase, to exfoliate from the cooling side heat exchanger by the generated bubble. 
     
     
         9 . The heat storage system according to  claim 6 , wherein the cooling side heat exchanger is formed by a heat transfer tube for flowing the heat medium for the cooling, and
 the solid phase exfoliation unit comprises:   a slide plate in which a heat transfer tube insertion hole for inserting the heat transfer tube is formed; and   an actuator for slidably translating the slide plate in a longitudinal direction of the heat transfer tube inserted in the heat transfer tube insertion hole so as to allow the heat storage material in the solid phase, which adheres to a surface of the heat transfer tube, to exfoliate.   
     
     
         10 . The heat storage system according to  claim 6 , wherein the solid phase exfoliation unit comprises a solid piece which is added to the heat storage material for colliding with the cooling side heat exchanger due to a flow of the heat storage material in the liquid phase, and allowing the heat storage material, which becomes the solid phase, to exfoliate from the cooling side heat exchanger. 
     
     
         11 . The heat storage system according to  claim 1 , further comprising:
 an exfoliating material in a liquid phase provided inside the heat storage tank, the exfoliating material having a smaller specific gravity then the heat storage material in the liquid phase, and not mixing with the heat storage material, and   the exfoliating material being arranged such that the cooling side heat exchanger arranged inside the heat storage tank is covered by the exfoliating material.   
     
     
         12 . The heat storage system according to  claim 1 , wherein the heat medium at high temperature is introduced into the cooling side heat exchanger when heating the heat storage material, and the heat storage material is heated by both the cooling side heat exchanger and the heating side heat exchanger.