Thermal storge medium using a hydrate and apparatus thereof, and method for producing the thermal storage medium

Abstract

The best mode aims to provide a thermal storage medium that improves the efficiency of heat exchange between the thermal storage medium and the cooling medium liquid in the cooling medium body, and that prevents supercool of the aqueous solution which produces hydrate. A large thermal storage capacity is attained using the latent heat of hydrate in the cooling medium body. By forming slurry of hydrate, the fluidability of the hydrate increases the efficiency of the heat exchange with cooling medium liquid. By sealing fine particles in the cooling medium body, the super-cool of aqueous solution is prevented. By changing position of the cooling medium body or by other means, the aqueous solution is agitated to keep the fine particles disperse and float in the aqueous solution, thus preventing the degradation of effect to prevent supercooling. Furthermore, a method for producing hydrate cooling medium body that can be generated at higher temperatures than the temperature of ice without using a thermal storage medium is suitably used in thermal storage system such as air-conditioners without using a special coolant.

What is claimed is:  
     
         1 . A thermal storage apparatus for using a hydrate thermal storage medium comprising: 
 a storage tank for storing a cooling medium liquid;    a refrigerating machine, connected with the storage tank via a pipe for cooling the cooling medium liquid, the cooling medium liquid circulating between the storage tank and the refrigerating machine;    a thermal storage body immersed in the cooling medium liquid, wherein the thermal storage medium comprising, 
 a hermetically sealed container,  
 an aqueous solution filled in the hermetically sealed container, to generate at least one selected from the group consisting of a primary hydrate and a secondary hydrate, wherein the primary hydrate has smaller hydration number and smaller heat capacity than the secondary hydrate, the secondary hydrate has larger hydration number and larger heat capacity than the primary hydrate,  
 fine particles to prevent the aqueous solution from super-cooling, the fine particles being contained in the hermetically sealed container.  
   
     
     
         2 . The thermal storage apparatus according to  claim 1 , further comprising container drive means for changing position of the container and moving the container in the cooling medium liquid to disperse the fine particles in the container.  
     
     
         3 . The thermal storage apparatus according to  claim 2 , wherein the container drive means comprises a fluid mechanism to change position of the container or to move the container by fluidizing the cooling medium liquid in the storage tank.  
     
     
         4 . The thermal storage apparatus according to  claim 2 , wherein the container drive means comprises an air-injection mechanism to change position of the container or to move the container by injecting air into the cooling medium liquid in the storage tank and by ascending air bubbles.  
     
     
         5 . The thermal storage apparatus according to  claim 2 , wherein the container drive means comprises a mechanical drive mechanism for mechanically changing position of the container or moving the container.  
     
     
         6 . The thermal storage apparatus according to  claim 1 , wherein the container of the thermal storage medium floats freely in the cooling medium liquid in the storage tank.  
     
     
         7 . The thermal storage apparatus according to  claim 1 , wherein the container of the thermal storage medium is supported in the storage tank in a free-rotational mode.  
     
     
         8 . The thermal storage apparatus according to  claim 1 , wherein the container of the storage tank provides at least one piece of blade members outside of the container, to promote changing position of the container or moving the container.  
     
     
         9 . The thermal storage apparatus according to  claim 1 , wherein the aqueous solution filled in the hermetically sealed container contains a guest compound, where the generation temperature of at least one selected from the group consisting of the primary hydrate and the secondary hydrate varies in accordance with the concentration of the aqueous solution.  
     
     
         10 . The thermal storage apparatus according to  claim 1 , wherein the fine particles have a diameter size of 100 μm or less.  
     
     
         11 . The thermal storage apparatus according to  claim 1 , wherein the fine particles have a diameter size of 10 μm or less.  
     
     
         12 . The thermal storage apparatus according to  claim 1 , wherein the fine particles have a diameter size of 100 μm or less, and the fine particles in the aqueous solution have a concentration of 0.1 mg/l or more.  
     
     
         13 . A hydrate thermal storage medium comprising: 
 an aqueous solution containing a guest compound to generate a hydrate slurry by cooling; and,    a corrosion inhibitor.    
     
     
         14 . The hydrate thermal storage medium according to  claim 13 , wherein the contained corrosion inhibitor is 5,000 wt.ppm or less of concentration.  
     
     
         15 . The hydrate thermal storage medium according to  claim 13 , wherein the guest compound is one selected from the group consisting of a tetra-n-butylammonium salt, a tetra-iso-amylammonium salt, a tetra-iso-butylphosphonium salt, and a tri-iso-amylsulfonium salt.  
     
     
         16 . A method for producing a hydrate thermal storage medium comprising the steps of: 
 (a) preparing an aqueous solution containing a guest compound to generate at least one selected from the group consisting of a primary hydrate and a secondary hydrate, wherein the primary hydrate has smaller hydration number and smaller heat capacity than the secondary hydrate, the secondary hydrate has larger hydration number and larger heat capacity than the primary hydrate; and,    (b) cooling the aqueous solution to produce at least one selected from the group consisting of the primary hydrate and the secondary hydrate.    
     
     
         17 . The method according to  claim 16 , wherein the aqueous solution is cooled at a rate of 6 kcal/hr-kg or more.  
     
     
         18 . The method according to  claim 16 , wherein the aqueous solution contains the guest compound at a concentration of from 10 to 26 wt. %.  
     
     
         19 . The method according to  claim 16 , wherein the aqueous solution is cooled to a temperature range of from 5° C. to 8° C.  
     
     
         20 . The method according to  claim 16 , wherein the guest compound is one selected from the group consisting of a tetra-n-butylammonium salt, a tetra-iso-amylammonium salt, a tetra-iso-butylphosphonium salt, or a tri-iso-amylsulfonium salt.  
     
     
         21 . A method for producing a hydrate slurry comprising the steps of: 
 (a) preparing an aqueous solution containing a guest compound by cooling, to generate at least one selected from the group consisting of a primary hydrate and a secondary hydrate, wherein the primary hydrate has smaller hydration number and smaller heat capacity than the secondary hydrate, the secondary hydrate has larger hydration number and larger heat capacity than the primary hydrate,and,    (b) cooling the aqueous solution and contacting nucleus particles as nucleus of the hydrate particles with the aqueous solution to produce the hydrate particles consisting of the primary hydrate and the secondary hydrate.    
     
     
         22 . The method according to  claim 21 , wherein the nucleus particles comprise hydrate particles.  
     
     
         23 . The method according to  claim 21 , wherein the nucleus particles comprise fine particles.  
     
     
         24 . The method according to  claim 21 , wherein the nucleus particles have a diameter size of 300 μm or less.  
     
     
         25 . The method according to  claim 21 , wherein the nucleus particles have a diameter size of 100 μm or less.  
     
     
         26 . The method according to  claim 21 , wherein the nucleus particles have a diameter size of 10 μm or less.  
     
     
         27 . The method according to  claim 21 , wherein the nucleus particles have a diameter size of 10 μm or less and the nucleus particles in the aqueous solution have a concentration of 0.1 mg/l or more.  
     
     
         28 . The method according to  claim 21 , wherein the nucleus particles comprise fine particles having heavier specific gravity than the specific gravity of the aqueous solution, and wherein the step of contacting the nucleus particles with the aqueous solution comprises dispersing and floating the nucleus particles in the aqueous solution.  
     
     
         29 . The method according to  claim 21 , wherein the step of contacting the nucleus particles with the aqueous solution comprises dispersing and floating the nucleus particles precipitated in the aqueous solution.  
     
     
         30 . The method according to  claim 21 , wherein the specific gravity of the nucleus particles is almost equal with the specific gravity of the aqueous solution, and the nucleus particles are dispersed and floated in the aqueous solution.  
     
     
         31 . The method according to  claim 21 , wherein the step of contacting the nucleus particles with the aqueous solution comprises the step of agitating the aqueous solution containing the nucleus particles.  
     
     
         32 . The method according to  claim 21 , wherein the step of contacting the nucleus particles with the aqueous solution comprises the step of contacting the aqueous solution with members to which surface the nucleus particles adhere.  
     
     
         33 . An apparatus for producing hydrate slurry by cooling an aqueous solution containing a guest compound and by generating hydrate particles comprising: 
 a generation heat exchanger having a heat transfer surface for cooling the aqueous solution and cooling the aqueous solution by contacting the aqueous solution with the heat transfer surface; and,    a nucleus particles supply mechanism for supplying the nucleus particles as nuclei of the hydrate particles to the aqueous solution passing through the generation heat exchanger.    
     
     
         34 . The apparatus according to  claim 33 , wherein the nucleus particles supply mechanism comprises a supply mechanism for supplying the hydrate particles.  
     
     
         35 . The apparatus according to  claim 33 , wherein the nucleus particles supply mechanism comprises a hydrate particle generation mechanism capable of operation independent from the generation heat exchanger.  
     
     
         36 . The apparatus according to  claim 33 , wherein the nucleus particles supply mechanism comprises a storage tank holding a part of the hydrate slurry produced in the generation heat exchanger.  
     
     
         37 . The apparatus according to  claim 33 , wherein the nucleus particles supply mechanism comprises a nucleus particle recovery mechanism for recovering the nucleus particles precipitated in the aqueous solution and for supplying the recovered nucleus particles to the generation heat exchanger.  
     
     
         38 . An apparatus for producing a hydrate slurry by cooling an aqueous solution containing a guest compound, to generate a primary hydrate and a secondary hydrate, wherein the primary hydrate has smaller hydration number and smaller heat capacity than the secondary hydrate, the secondary hydrate has larger hydration number and larger heat capacity than the primary hydrate by generating hydrate particles, comprising: 
 a generation heat exchanger having a heat transfer surface for cooling the aqueous solution and cooling the aqueous solution by the contacting the aqueous solution with the heat transfer surface; and,    at least one part of a surface of members, wherein the surface contacts with the aqueous solution in the generation heat exchanger, and wherein nucleus particles as nuclei of the hydrate particles adhere to the surface.    
     
     
         39 . The apparatus according to  claim 38 , wherein the generation heat exchanger comprises: 
 a cylindrical heat transfer surface,    a separation blade member rotating, simultaneously with contacting and sliding on the heat transfer surface for separating the hydrate generated on the heat transfer surface, and,    a surface of the separation blade member having a surface adhered by the nucleus particles.    
     
     
         40 . An apparatus for producing a hydrate slurry by cooling an aqueous solution containing a guest compound and by generating hydrate particles, comprising: 
 a generation heat exchanger having a heat transfer surface for cooling the aqueous solution and cooling the aqueous solution by contacting the aqueous solution with the heat transfer surface; and,    an agitation mechanism for dispersing and floating the nucleus particles as nuclei of the hydrate particles in the aqueous solution.    
     
     
         41 . A Hydrate thermal storage medium comprising: 
 an aqueous solution filled in the hermetically sealed container, to generate at least one selected from the group consisting of a primary hydrate and a secondary hydrate, wherein the primary hydrate has smaller hydration number and smaller heat capacity than the secondary hydrate, the secondary hydrate has larger hydration number and larger heat capacity than the primary hydrate.    
     
     
         42 . The thermal storage medium according to  claim 41 , wherein the aqueous solution contains the guest compound, the concentration being from 10% to 26%.  
     
     
         43 . The thermal storage medium according to  claim 41 , wherein the guest compound contained in the aqueous solution is one selected from the group consisting of a tetra-n-butylammonium salt, a tetra-iso-amylammonium salt, a tetra-iso-butylphosphonium salt, and a tri-iso-amylsulfonium salt.  
     
     
         44 . A hydrate cold thermal storage transporting medium comprising: 
 a primary hydrate and a secondary hydrate, wherein the primary hydrate has smaller hydration number and smaller heat capacity than the secondary hydrate, the secondary hydrate has larger hydration number and larger heat capacity than the primary hydrate.    
     
     
         45 . The hydrate cold thermal storage transporting medium according to  claim 44 , wherein the aqueous solution contains the guest compound, the concentration being from 10% to 26%.  
     
     
         46 . The hydrate cold thermal storage transporting medium according to  claim 44 , wherein the guest compound contained in the aqueous solution is one selected from the group consisting of a tetra-n-butylammonium salt, a tetra-iso-amylammonium salt, a tetra-iso-butylphosphonium salt, and a tri-iso-amylsulfonium salt.  
     
     
         47 . The hydrate thermal storage medium according to  claim 13 , wherein the contained corrosion inhibitor is at least one selected from the group consisting of sodium nitrite, sodium sulfite, sodium pyrophosphate, and benzotriazole.  
     
     
         48 . The method according to  claim 16 , the aqueous solution is cooled to generation temperature or less of the secondary hydrate.