Heat storage device

Abstract

To provide a heat storage device that eliminates the need of a complicated mechanism which requires a high manufacturing cost, can be compactified, and can supply a large amount of heat immediately by quickly changing the phase of the whole latent heat storage material after the latent heat storage material encapsulated in a container is nucleated.SOLUTION: A heat storage device 10 includes: a seed crystal part 12 storing an overcool prevention medium 15; a heat storage part 11 storing a latent heat storage material 16 communicated to the seed crystal part intermittently; heat transfer means for transferring heat to the latent heat storage material; and a pressing member 18 for compressing the latent heat storage material 16. After a liquid phase latent heat storage material 16L comes into contact with a solid phase latent heat storage material 16S of the seed crystal part 12 and is nucleated, the pressing member 18 is controlled to perform operation of compressing the liquid phase latent heat storage material 16L.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present invention relates to a heat storage device, and more particularly to a heat storage device using a latent heat storage material and a nucleation means. [Background technology]

[0002] BACKGROUND ART Various heat storage devices have been proposed in the past that temporarily store thermal energy emitted from a moving body such as a vehicle in a heat storage material and use it when starting the engine in order to promote warm-up, improve fuel efficiency, purify exhaust gases, and improve heating performance.

[0003] For example, Patent Document 1 describes a heat storage device that includes a sealed container made of a flexible material, a heat storage element made of a latent heat storage material sealed in the sealed container and capable of storing heat in a supercooled state, a supercooling release member that is installed in the sealed container and changes shape as the sealed container deforms to release the supercooled state of the heat storage element, a heat exchange chamber that houses multiple sealed containers and circulates a heat transfer medium from the object to be warmed up to perform heat exchange between the heat transfer medium and the heat storage element in the sealed container, and a pressurizing mechanism that simultaneously pressurizes and deforms the multiple sealed containers housed in the heat exchange chamber.

[0004] The heat storage principle of supercooled latent heat storage materials such as those described in Patent Document 1 is that when the material is heated above its melting point in a solid phase, it transforms into a liquid phase. This liquid phase does not recrystallize even when cooled below its melting point, but remains in a supercooled state, and the heat absorbed during heating is stored as latent heat. When it is desired to utilize this absorbed heat, the material is nucleated to break down the supercooled state, which initiates recrystallization, and the stored latent heat can be extracted as dissipated heat accompanying the state change from liquid to solid.

[0005] In order to nucleate a liquid-phase latent heat storage material in a supercooled state at any timing and cause it to change into a solid phase, it is known to change the shape of an elastic metal piece in contact with the liquid-phase latent heat storage material, or to bring the liquid-phase latent heat storage material into contact with a seed crystal, etc. In order to stably maintain the seed crystal, it is known to use a supercooling prevention agent that forcibly changes the phase of the heat storage material to a solid below its melting point. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-54162 Summary of the Invention [Problem to be solved by the invention]

[0007] Considering the installation of a latent heat storage material in a vehicle, a large amount of energy is required, which increases the capacity of the latent heat storage material. However, in the case of a supercooled latent heat storage material, once nucleation begins, the phase change propagates and heat is released, but the propagation speed is slow. Therefore, if nucleation occurs from one end of the latent heat storage material sealed in a container, it takes several tens of seconds for the nucleation to reach the opposite end, which poses a problem that the heat cannot be released quickly and supplied when needed.

[0008] Patent Document 1 describes that by producing a large number of sealed containers filled with latent heat storage material and equipped with cooling release members inside, and housing them in a heat storage device, the volume of the latent heat storage material nucleated by a single nucleation means is reduced, and the shape of all of the cooling release members is deformed at once using a pressure mechanism, the entire latent heat storage material in the heat storage device can be rapidly phase-changed and heat can be released. However, providing a large number of such sealed containers increases manufacturing costs, and there are problems in that the device becomes larger in size compared to the capacity of the latent heat storage material.

[0009] In view of the above problems, the present invention aims to provide a heat storage device that does not require a complex mechanism that increases manufacturing costs, can be made compact, and can quickly supply a large amount of heat by quickly changing the phase of the entire latent heat storage material after the latent heat storage material sealed in the container nucleates. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention provides a heat storage device comprising a container in which a latent heat storage material is sealed, a heat transfer means to the latent heat storage material, a nucleation means for breaking down the supercooled state of the latent heat storage material, the nucleation means being arranged in the container, and a pressurization means for pressurizing the latent heat storage material, the pressurization means performing an operation of pressurizing the latent heat storage material following nucleation of the latent heat storage material by the nucleation means. [Effects of the Invention]

[0011] According to the present invention, the liquid phase latent heat storage material sealed in the container is nucleated by a nucleation means, and then the latent heat storage material in the container is pressurized by a pressure means that can be constructed with a simple mechanism.Surprisingly, phase changes begin at multiple locations other than the location where nucleation occurred by the nucleation means, and therefore the entire latent heat storage material in the container becomes solid in a short period of time, making it possible to quickly supply large amounts of heat when heat is needed. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view schematically showing a first embodiment of a heat storage device according to the present invention. [Figure 2A] FIG. 3 is a flow diagram for schematically explaining heat storage and heat release in the heat storage device shown in FIG. [Figure 2B] FIG. 3 is a flow diagram for schematically explaining heat storage and heat release in the heat storage device shown in FIG. [Figure 3] FIG. 4 is a cross-sectional view schematically showing another embodiment of a heat storage device according to the present invention. [Figure 4] FIG. 5 is a flow diagram for schematically explaining heat storage and heat release in a second embodiment of the heat storage device according to the present invention. [Figure 5] FIG. 2 is a schematic diagram showing the state change of a latent heat storage material in a solidification rate test of a comparative example (no pressure applied). [Figure 6] FIG. 2 is a schematic diagram showing the state change of the latent heat storage material in a solidification rate test of the latent heat storage material of the example (applied pressure). DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat storage device according to the present invention will now be described with reference to the accompanying drawings.

[0014] [Heat storage device of the first embodiment] 1, the heat storage device 10 of the first embodiment mainly includes a heat storage container 11 in which a latent heat storage material 16 is sealed, and a seed crystal container 12 that contains a supercooling prevention medium 15 as nucleation means. In addition, an on-off valve 13 such as a solenoid valve is provided between the heat storage container 11 and the seed crystal container 12, which allows the liquid phase latent heat storage material 16 to intermittently communicate between the heat storage container 11 and the seed crystal container 12, and the seed crystal container 12 also contains the latent heat storage material 16. Opening and closing of the on-off valve 13 is controlled by a control circuit (not shown) of the heat storage device 10.

[0015] The heat storage container 11 and the seed crystal container 12 are not entirely filled with the latent heat storage material 16, and have a gas phase 17. The gas phase 17 is not particularly limited, but may contain, for example, air, an inert gas, or nitrogen. The volumetric proportion of the gas phase 17 in the heat storage container 11 is not particularly limited as long as it is a proportion that allows pressurization of the latent heat storage material 16 in the heat storage container 11, as described below, but is preferably 2 to 10%, and more preferably 5 to 10%, for example, in consideration of the volume change between the solid phase and the liquid phase.

[0016] The latent heat storage material 16 is not particularly limited as long as it is a substance that changes into a liquid phase when heated above its melting point in a solid phase, and then remains in a supercooled liquid state even when cooled below its melting point, and can store the heat absorbed during heating as latent heat. For example, calcium chloride hydrate, sodium acetate hydrate, sodium sulfate hydrate, etc. are preferred.

[0017] The heat storage container 11 and the seed crystal container 12 may be capable of withstanding the heating and cooling required to change the phase of the latent heat storage material 16 between the solid and liquid phases, and may be made of the same material and structure as containers for accommodating latent heat storage materials in conventional heat storage devices. For example, materials such as stainless steel, aluminum alloy, and brass, which have good thermal conductivity, may be used, and the structure may be a rectangular parallelepiped or any other three-dimensional shape. Furthermore, a heat transfer unit (not shown), such as a fin for increasing the heat transfer area, may be attached to the outer periphery of the heat storage device 10 as a heat transfer means to the latent heat storage material 16. Fin-shaped fins, corrugated fins, or the like may be used as the fins.

[0018] The seed crystal container 12 is provided with a filter unit 14 that divides the container into two compartments. One of the two compartments is not in contact with the flow path of the on-off valve 13, and a supercooling prevention medium 15 is disposed in this compartment that is not in contact with the flow path of the on-off valve 13. The filter unit 14 is not particularly limited as long as it allows the latent heat storage material 16 to pass freely but does not allow the supercooling prevention medium 15 to pass through; for example, a sponge, a metal mesh, a nonwoven fabric, or the like can be used. The filter unit 14 can prevent the supercooling prevention medium 15 from migrating to the other compartment in the seed crystal container 12 that is in contact with the flow path of the on-off valve 13, and therefore the supercooling prevention medium 15 can be stored in the seed crystal container 12.

[0019] The supercooling prevention medium 15 is not particularly limited as long as it is a substance that forcibly changes the phase of the latent heat storage material 16 to a solid at a temperature below its melting point. For example, a porous body carrying a salt of an alkaline earth metal that is insoluble or poorly soluble in water is preferred.

[0020] As the alkaline earth metal, strontium, barium, etc. are preferred from the viewpoint of exhibiting an excellent supercooling prevention effect as a supercooling inhibitor and generating a salt that is insoluble or poorly soluble in water. Furthermore, as the alkaline earth metal salt that is insoluble or poorly soluble in water, strontium sulfate, strontium carbonate, barium sulfate, barium carbonate, etc. are preferred.

[0021] The porous body is not particularly limited as long as it has pores capable of supporting the supercooling inhibitor, but may be, for example, activated carbon, an organic porous body such as a porous resin membrane, or an inorganic porous body such as porous ceramic, zeolite, or silica gel. Activated carbon is sometimes broadly classified by the type of raw material, and may be wood-based or coal-based, for example, coconut shell, coal, or petroleum pitch. The shape of the porous body is not particularly limited, and may be, for example, granular, rectangular, plate-like, or pellet-like.

[0022] In this way, by using a supercooling prevention medium 15 in which a supercooling prevention agent, which is a salt that is insoluble or poorly soluble in water, is supported on a porous body, it is possible to prevent the supercooling prevention agent from flowing out of the porous body of the supercooling prevention medium 15, passing through the flow path of the opening / closing valve 13, and being mixed into the heat storage container 11 that contains the latent heat storage material 16.

[0023] In this specification, "insoluble in water" refers to a substance whose solubility in 100 g of water at room temperature (25°C) is 0.01 g or less. "Slightly soluble in water" refers to a substance whose solubility in 100 g of water at room temperature (25°C) is 0.1 g or less but more than 0.01 g. The solubility of strontium sulfate is 0.014 g / 100 ml of water, making it slightly soluble in water. The solubility of strontium carbonate is 0.0011 g / 100 ml of water, making it insoluble in water. The solubility of barium sulfate is 2.5 x 10 -4 g / 100 ml of water and is insoluble in water.

[0024] The heat storage container 11 is provided with a pressing member 18 that is slidably disposed relative to the inner circumferential surface of the heat storage container 11 in order to pressurize the latent heat storage material 16 in the heat storage container 11. The pressing member 18 can pressurize the latent heat storage material 16 by sliding within the heat storage container 11 toward the on-off valve 13, and can release the pressure on the latent heat storage material 16 by sliding toward the opposite side of the on-off valve 13. Such operations are controlled by a control circuit (not shown) of the heat storage device 10. The pressing member 18 is preferably made of the same material as the heat storage container 11 and the seed crystal container 12. Such a pressing member 18 allows the heat storage device 10 to be made compact without a complex structure, and allows the latent heat storage material 16 to be pressurized with simple control.

[0025] The heat storage and heat release of the heat storage device 10 having such a configuration will be described with reference to Figures 2A and 2B. First, in the heat storage device 10 in a state where heat storage is complete and heat release is not yet performed, as shown in Figure 2A(a), the on-off valve 13 is closed and liquid-phase latent heat storage material 16L is contained in the heat storage container 11. Since a supercooling prevention medium 15 is placed in the seed crystal container 12, the inside of the seed crystal container 12 contains solid-phase latent heat storage material 16S, i.e., a seed crystal. In addition, the pressing member 18 is positioned so that the latent heat storage material 16 in the heat storage container 11 is under atmospheric pressure.

[0026] Next, when heat is to be released from the heat storage device 10, as shown in Fig. 2A(b), when the on-off valve 13 of the heat storage device 10 is opened, the liquid phase latent heat storage material 16L in the heat storage container 11 flows into the seed crystal container 12 and comes into contact with the solid phase latent heat storage material 16S that serves as the seed crystal in the seed crystal container 12. As a result, the liquid phase latent heat storage material 16L in contact with the seed crystal nucleates and begins to solidify, and heat release begins.

[0027] 2A(c), by sliding the pressing member 18 of the heat storage container 11 toward the on-off valve 13 side to pressurize the liquid phase latent heat storage material 16L, the liquid phase latent heat storage material 16L starts to solidify without coming into contact with the seed crystal at a plurality of other locations in the heat storage container 11, in addition to the location that contacted the seed crystal. Therefore, the liquid phase latent heat storage material 16L in the heat storage container 11 does not gradually become solid from the seed crystal container 12 side toward the opposite side, but solid phase latent heat storage material 16S is generated at a plurality of locations, and all of it becomes solid in a short period of time.

[0028] Once nucleation begins in the latent heat storage material 16, the phase change propagates and heat is released, but because the propagation speed is slow, if nucleation occurs from one end of the heat storage container 11, it takes several tens of seconds for the nuclei to reach the opposite end, which means that heat cannot be released quickly and supplied when needed from the heat storage device 10. In this embodiment, as described above, after opening the on-off valve 13, the pressing member 18 is subsequently slid to pressurize the liquid phase latent heat storage material 16L, so that all of the liquid phase latent heat storage material 16L in the heat storage container 11 can be converted into solid phase latent heat storage material 16S in a short time, and therefore a large amount of heat begins to be generated immediately, making it possible to quickly supply heat from the heat storage device 10 when heat is needed.

[0029] The distance by which the pressing member 18 is slid is not particularly limited as long as it is a distance that can apply pressure to the liquid-phase latent heat storage material 16L that has come into contact with the seed crystal and nucleated to such an extent that solidification begins even in areas that are not in contact with the seed crystal, but for example, a distance that can compress the volume inside the heat storage container 11 to 95% or less is preferable. If the volume inside the heat storage container 11 is compressed too much, the repulsive force that pushes back the pressing member 18 becomes too large, so a distance of 85% or more is preferable.

[0030] 2B(d), the heat storage container 11 contains the solid-phase latent heat storage material 16S. In this state, heat storage begins in the heat storage device 10. Because the heat storage container 11 and the seed crystal container 12 both contain the solid-phase latent heat storage material 16S, the open / close valve 13 cannot be closed.

[0031] When heat storage is completed, as shown in Fig. 2B(e), the latent heat storage material 16 in the heat storage container 11 and the seed crystal container 12 is heated to a temperature equal to or higher than the melting point, and therefore both become liquid-phase latent heat storage material 16L. When this state is reached, as shown in Fig. 2B(f), the pressing member 18 is slid toward the opposite side from the opening / closing valve 13 and returned to its original position, releasing the pressure on the liquid-phase latent heat storage material 16L and closing the opening / closing valve 13.

[0032] Thereafter, when the heat storage device 10 is cooled to below its melting point, the latent heat storage material 16 in the seed crystal container 12 changes to a solid phase because the supercooling prevention medium 15 is disposed therein. Therefore, as shown in FIG. 2A(a), the latent heat storage material 16 again becomes ready to release heat. In this way, the heat storage device 10 of this embodiment can repeatedly release and store heat.

[0033] Unlike the supercooling prevention medium 15 of this embodiment, if the supercooling prevention agent is not supported on a porous body, the supercooling prevention agent will be mixed into the latent heat storage material. This is because, when heat storage is completed, seed crystals consisting of a latent heat storage material and a supercooling prevention agent remain in the liquid-phase latent heat storage material 16L in the seed crystal container 12, and these seed crystals flow through the flow path of the on-off valve 13 to the liquid-phase latent heat storage material 16L in the heat storage container 21. If the supercooling prevention agent is mixed into the heat storage container 21, the liquid-phase latent heat storage material 16L in the heat storage container 21 will not reach a supercooled state, and a problem will arise in that it will no longer be able to store heat.

[0034] In the heat storage device 10 of this embodiment, the supercooling prevention agent is present in the seed crystal container 12 as the supercooling prevention medium 15 supported on a porous body, and because it is a salt that is insoluble or poorly soluble in water, it does not flow out of the porous body into the latent heat storage material, and therefore it is possible to prevent the supercooling prevention agent from being mixed into the heat storage container 21. Furthermore, because the supercooling prevention medium 15 is in a solid form like a porous body, it is possible to easily prevent its movement into the heat storage container 21 by using the filter part 14 or the like.

[0035] Furthermore, in the embodiment of the heat storage device 10 shown in Figures 1 and 2, a pressing member 18 is arranged as a means for pressurizing the latent heat storage material 16, and is slid and moved to pressurize the latent heat storage material 16. However, the present invention is not limited to this, and other configurations can be adopted as long as the latent heat storage material 16 in the heat storage container 11 can be pressurized.

[0036] For example, as shown in Fig. 3, in the heat storage device 10A, a gas cylinder 19 is installed as a means for pressurizing the latent heat storage material 16, which supplies gas to the gas phase 17 of the heat storage container 11 and recovers the gas in the gas phase 17. With this configuration, during heat release, the open / close valve 13 is opened, and then gas is supplied from the gas cylinder 19 into the heat storage container 11 to increase the pressure inside the heat storage container 11, thereby pressurizing the latent heat storage material 16. Furthermore, when heat storage is completed, the gas is recovered from inside the heat storage container 11 by the gas cylinder 19, thereby releasing the pressure of the latent heat storage material 16.

[0037] Furthermore, the heat storage device of the present invention is not limited to the above-described embodiment, and can be embodied in a wide variety of different ways. For example, in the embodiment shown in Figures 1 to 3, a seed crystal container containing a supercooling prevention medium in which a supercooling prevention agent is supported on a porous body is used as the nucleation means, but a nucleation means such as that of the second embodiment described below may also be used. Note that detailed description of the same configuration as the first embodiment will be omitted.

[0038] [Heat storage device of second embodiment] As shown in Fig. 4, the heat storage device 10A of the second embodiment mainly includes a needle valve 30 and a main container 20 that houses a seal portion 31 of the needle valve 30. The main container 20 mainly includes a cylindrical seed crystal portion 22 that houses a supercooling prevention medium 32 that carries a salt of an alkaline earth metal that is insoluble or poorly soluble in water, and a cylindrical heat storage portion 21 that is in intermittent communication with the seed crystal portion. A latent heat storage material 26 is sealed in the heat storage portion 21 and the seed crystal portion 22. Furthermore, the heat storage portion 21 and the seed crystal portion 22 are not entirely filled with the latent heat storage material 26, and a gas phase 27 is present.

[0039] The heat storage device 10B is provided with a narrowed section 23 in the center of the main container 20, the narrowed section 23 having an inner diameter smaller than that of the heat storage section 21 and the seed crystal section 22, thereby dividing the inside of the main container 20 into the heat storage section 21 and the seed crystal section 22. The seed crystal section 22 is also provided with a base end side of a needle valve 30 having a seal section 11 at its tip that moves to open and close the narrowed section 23.

[0040] The needle valve 30 includes, in order from its tip, a conical seal portion 31 larger than the inner diameter of the narrowed portion 23, a supercooling prevention medium 32, and a spindle 33 for moving the seal portion 31 so as to be able to open and close relative to the narrowed portion 23. The angle of the conical surface of the seal portion matches the angle of the conical surface connecting the narrowed portion 23 and the seed crystal portion 22. The opening and closing movement of the seal portion 31 relative to the narrowed portion 23 is controlled by a control circuit (not shown) of the heat storage device 10B.

[0041] The surface of sealing portion 31 is formed from an elastic material, and can close narrowed portion 23 by pressing against narrowed portion 23 of main container 20. Supercooling prevention medium 32 has a surface formed from the same elastic material as sealing portion 31, and the surface of this elastic material carries a supercooling prevention agent, a salt of an alkaline earth metal that is insoluble or poorly soluble in water.

[0042] The elastic body of the sealing portion 31 is not particularly limited as long as it can adhere to the inner surface of the narrowed portion 23 so as to block communication between the heat storage portion 21 and the seed crystal portion 22. Examples of the elastic body include rubber, elastomer, and resin. Rubber is particularly preferred because of its flexibility and durability against repeated heating and cooling. Specific examples of rubber include silicone rubber, nitrile rubber, fluororubber, and butyl rubber. Using a material with excellent flexibility can mitigate volume changes that occur when the latent heat storage material 26 undergoes a phase change and stresses that occur when the latent heat storage material 26 undergoes a phase change during the crystal growth process.

[0043] It is also preferable to use a material in which the sealing material (i.e., elastic body) of the sealing portion 31 and the carrier carrying the supercooling prevention agent of the supercooling prevention medium 32 are integrally formed from the same material. By integrally forming the sealing portion 31 and the supercooling prevention medium 32, the number of parts of the heat storage device 10B can be reduced, thereby lowering manufacturing costs, and the sealing performance of the sealing portion 31 can be ensured while the supercooling prevention medium 32 allows crystals of the supercooling prevention agent to be exposed on its surface.

[0044] The heat storage unit 21 is provided with a pressing member 28 that is slidably disposed on the inner circumferential surface of the cylindrical heat storage unit 21 in order to apply pressure to the latent heat storage material 26 inside the heat storage unit 21. The pressing member 28 can apply pressure to the latent heat storage material 26 by sliding inside the heat storage unit 21 toward the narrowed portion 23, and can release the pressure on the latent heat storage material 26 by sliding toward the opposite side from the narrowed portion 23.

[0045] Heat storage and heat release of the heat storage device 10B having such a configuration will be described with reference to Fig. 4. First, in the heat storage device 10B in a state where heat storage is completed and heat release is not yet performed, the needle valve 30 is closed and the seal portion 31 is in close contact with the narrowed portion 23, as shown in Fig. 4(a). A liquid phase latent heat storage material 26L is accommodated in the heat storage portion 21. A supercooling prevention medium 32 is arranged in the seed crystal portion 22, and therefore the inside of the seed crystal portion 22 contains a solid phase latent heat storage material 26S, i.e., a seed crystal.

[0046] Next, when heat is released from the heat storage device 10B, as shown in FIG. 4(b), the needle valve 30 is moved to open the narrowed portion 23 of the heat storage device 10B, causing the liquid-phase latent heat storage material 26L in the heat storage unit 21 to flow through the flow path 25 of the narrowed portion 23 into the seed crystal unit 22 and come into contact with the solid-phase latent heat storage material 26S that serves as the seed crystal in the seed crystal unit 22. This causes the liquid-phase latent heat storage material 26L to nucleate and begin solidification. Then, following the movement of the needle valve 30, the pressing member 28 is slid toward the narrowed portion 23 to pressurize the liquid-phase latent heat storage material 26L. As a result, the liquid-phase latent heat storage material 26L begins to solidify not only at the location where it contacted the seed crystal but also at other locations in the heat storage unit 21 without coming into contact with the seed crystal, and solid-phase latent heat storage material 16S is produced at multiple locations.

[0047] 4(c), the liquid phase latent heat storage material 26L in the heat storage unit 21 can be changed into solid phase latent heat storage material 26S in a short time. In this way, since a large amount of heat generation starts immediately after the needle valve 30 is moved, it is possible to quickly supply heat from the heat storage device 10B when heat is needed.

[0048] Until heat dissipation is complete, the latent heat storage material 26S is in solid phase inside the heat storage unit 21. In this state, heat storage is started in the heat storage device 10B. Because the latent heat storage material 26S inside both the heat storage unit 21 and the seed crystal unit 22 is in solid phase, the needle valve 30 cannot be closed.

[0049] When heat storage is completed, the latent heat storage material 26 in the heat storage section 21 and the seed crystal section 22 is heated to a temperature above its melting point, and therefore both are in the liquid phase. When this state is reached, the needle valve 30 can be closed.

[0050] Thereafter, when the heat storage device 10B is cooled to below its melting point, the latent heat storage material 26L in the seed crystal portion 22 changes to a solid phase because the supercooling prevention medium 32 is disposed therein. Therefore, the latent heat storage material 26L again becomes ready to release heat, as shown in FIG. 4(a). In this way, the heat storage device 10B of the second embodiment can repeatedly release and store heat.

[0051] Furthermore, in the first and second embodiments, the case where a seed crystal container or a seed crystal portion is provided as the nucleation means has been described, but the present invention is not limited to these, and other configurations can be adopted as long as they can nucleate the latent heat storage material. For example, as described in Patent Document 1, a shape change of an elastic metal piece can also nucleate a supercooled liquid phase latent heat storage material and change it to a solid phase. In the present invention, by nucleating the latent heat storage material using such other nucleation means and then pressurizing the latent heat storage material, as described above, the latent heat storage material can be completely solidified in a short period of time, and a large amount of heat can be quickly supplied from the heat storage device. [Example]

[0052] Examples and comparative examples of the present invention will be described below.

[0053] [Solidification rate test of latent heat storage material] A latent heat storage material and nucleation means were enclosed in a polyvinyl chloride bag (100 mm diameter, 13 mm thick). The latent heat storage material was 80.9 g of sodium acetate trihydrate (C2H3NaO2·3H2O). The nucleation means was a trigger (a metal disk) used in commercially available recycled hand warmers. The bag was then heated above 58°C, the melting point of the latent heat storage material, to liquefy the material, and then slowly cooled to room temperature. Next, the trigger was pressed with a finger from the outside of the bag, and the time it took for the latent heat storage material inside the bag to solidify was measured. The change in the state of the latent heat storage material during this time was also observed. This test was repeated five times (without pressure). The test results are shown in Table 1 and Figure 5.

[0054] In addition, after pressing the trigger from the outside of the bag, pressure was immediately applied to the bag by hand to deform it, and then it was pressed down once, and then returned to its original shape, and the time until all of the latent heat storage material inside the bag solidified was measured. Changes in the state of the latent heat storage material during this time were also observed. This test was also repeated five times (with pressure applied). The test results are shown in Table 1 and Figure 6.

[0055] [Table 1]

[0056] Figure 5 shows the chronological changes in the state of the latent heat storage material 51 in the bag 50 during a test without pressurization. The bag 50 contains a liquid latent heat storage material 51L and a trigger 52. When the trigger 52 was pressed, nucleation 53 was observed near the trigger 52, where heat was generated and solidification of the latent heat storage material 51L began (see Figure 5(a)). Solidification then proceeded radially from the nucleation point, and solid latent heat storage material 52S was observed around the trigger 52 (see Figure 5(b)). Solidification then proceeded radially from the trigger 52, gradually spreading the solid latent heat storage material 52S (see Figure 5(c)). Finally, the entire bag 50 became solid latent heat storage material 52S (see Figure 5(d)). In the test without pressurization, the average time required for the entire material to solidify was 13.8 seconds, as shown in Table 1.

[0057] Figure 6 shows the chronological changes in the state of the latent heat storage material 51 in the bag 50 during the pressurized test. When the trigger 52 was pressed, nuclei 53 were observed near the trigger 52, where heat was generated and solidification of the latent heat storage material 51L began (see Figure 6(a)). Next, when pressure 54 was applied to the bag 50 as described above, similar nuclei 53 were observed at multiple locations away from the trigger 52 (see Figure 6(b)). Then, solidification progressed radially from each nucleated point, and the solid latent heat storage material 52S gradually spread (see Figure 6(c)). Finally, the entire bag 50 became solid latent heat storage material 52S (see Figure 6(d)). In the pressurized test, as shown in Table 1, it took an average of 9.2 seconds for the entire material to solidify.

[0058] Therefore, by applying pressure to the latent heat storage material after nucleation, the time from when the nucleation began to occur until the entire material solidified was shortened by approximately 33% compared to when no pressure was applied. Furthermore, an analysis of variance of these test results showed that the effect of pressure was statistically significant.

[0059] When the bag was pressurized in the same manner as above without pressing the trigger, the latent heat storage material in the bag remained liquid and maintained its supercooled state. From this, it can be inferred that although simply pressurizing supercooled latent heat storage material cannot nucleate the latent heat storage material, if solidification of the latent heat storage material has begun in a portion of the bag, the entire latent heat storage material in the bag becomes more likely to solidify, and it is possible to nucleate and solidify with less energy than the energy required for nucleation to break down the supercooled state. [Explanation of symbols]

[0060] 10 Heat storage device 11 Heat storage container 12 Seed crystal container 13 Opening and closing valve 14 Filter section 15 Supercooling prevention medium 16 Latent heat storage material 17 Gas Phase 18 Pressing member 19 Air Cylinder 20 Main container 21 Heat storage section 22 Seed crystal part 23 Opening and closing valve 25 flow path 26 Latent heat storage material 27 Gas Phase 28 Pressing member 30 Needle valve 31 Seal part 32 Supercooling prevention medium 33 Spindle 51 Latent heat storage material 52 Nucleator 53 Nucleus point 54 Pressurization

Claims

1. a container in which a latent heat storage material is sealed; A heat transfer means to the latent heat storage material; A nucleation means for breaking down the supercooled state of the latent heat storage material, the nucleation means being disposed in the container; a pressurizing means for pressurizing the latent heat storage material, the pressurizing means performing an operation of pressing the latent heat storage material following nucleation of the latent heat storage material by the nucleation means; A heat storage device comprising:

2. The heat storage device according to claim 1 , wherein the pressurizing means comprises a pressing member slidably disposed in a container in which the latent heat storage material is sealed.

3. the container in which the latent heat storage material is sealed includes a seed crystal portion containing a supercooling prevention medium, and a heat storage portion containing the latent heat storage material and capable of being intermittently communicated with the seed crystal portion; the nucleation means is a seed crystal portion containing the supercooling prevention medium, The heat storage device according to claim 1 or 2, wherein the pressurizing means performs an operation of pressurizing the latent heat storage material following the communication opening operation, and performs an operation of releasing the pressure on the latent heat storage material following the communication closing operation.

4. the container in which the latent heat storage material is sealed includes a seed crystal portion containing a supercooling prevention medium, and a heat storage portion containing the latent heat storage material and capable of being intermittently communicated with the seed crystal portion; the heat storage device further includes a valve having a seal portion at a tip thereof that moves between the seed crystal portion and the heat storage portion so as to be able to open and close, a base end of the valve is disposed on the seed crystal portion side of the heat storage device, and the supercooling prevention medium is disposed in a portion of the valve closer to the base end than the seal portion; The heat storage device according to claim 1 or 2, wherein the pressurizing means performs an operation of pressurizing the latent heat storage material following an opening operation of the valve, and performs an operation of releasing the pressure on the latent heat storage material following a closing operation of the valve.

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