Chemical heat storage device

Abstract

To provide a chemical heat storage device which can inhibit loss of radiation heat from a chemical heat storage medium held in a storage container to improve heat storage efficiency during heat exchange in chemical heat storage.SOLUTION: In order to achieve the above object, a chemical heat storage device includes: a heat storage medium; a heat exchange part which conducts heat exchange between the heat storage medium and a heat medium fluid; and a storage container which stores the heat storage medium and the heat exchange part. A first heat reflection member which is disposed spaced apart from an inner wall of the storage container is provided between the heat storage medium and the storage container. The chemical heat storage device enables radiation heat occurring from the heat storage medium due to the heat exchange to return to the heat storage medium side by the first heat reflection member. Further, the first heat reflection member is disposed spaced apart from the inner wall of the storage container to inhibit absorption of reaction heat into the storage container and thereby attain further heat insulation effect.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chemical heat storage device. [Background technology]

[0002] Factories, waste incineration plants, and other facilities generate huge amounts of waste heat, and from the perspective of energy conservation and the effective use of unused energy, research and development is being conducted on heat storage systems that store and utilize this waste heat. In particular, chemical heat storage, which utilizes the chemical reaction of a substance, is known to have a much higher heat storage density than sensible heat storage or latent heat storage, and if the substance is stable before and after the chemical reaction, there is almost no heat loss, and no heat loss occurs during long-term heat storage.

[0003] For example, Patent Document 1 discloses a chemical heat storage reactor that stores thermal energy such as waste heat in a chemical heat storage material that accumulates thermal energy in the form of a chemical reaction, and stores the stored chemical heat storage material or transports it to a place where thermal energy is required for use. Patent Document 1 describes, as a specific example of chemical heat storage, a system that uses a calcium hydroxide-based heat storage material as a chemical heat storage material in order to efficiently store high-temperature waste heat exceeding 400 degrees. When high-temperature waste heat is supplied to calcium hydroxide as a heat supply fluid, calcium oxide is produced by a dehydration reaction, and since this reaction is an endothermic reaction, it manifests as a heat storage effect. On the other hand, when water (water vapor) is supplied as a heat receiving fluid, calcium oxide produces calcium hydroxide by a hydration reaction, and since this reaction is an exothermic reaction, it manifests as a heat dissipation effect. Patent document 1 also discloses an apparatus in which multiple fluid (heat supply fluid / heat receiving fluid) flow paths are arranged alternately with multiple chemical heat storage materials within a storage container, and heat receiving and dissipating plates are arranged along the fluid flow paths to increase the efficiency of heat exchange between the chemical heat storage material and the fluid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-118315 A Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional chemical heat storage devices, waste heat was effectively utilized by selecting a chemical heat storage material and by improving the heat exchange efficiency between the chemical heat storage material and the fluid. However, in order to store high-temperature waste heat exceeding 400 degrees, heat exchange is naturally performed at high temperatures, and the radiation heat loss from the holding member itself that holds the chemical heat storage material cannot be ignored. Therefore, an object of the present invention is to provide a chemical heat storage device that can suppress radiant heat loss from a chemical heat storage material held in a storage container during heat exchange in chemical heat storage, thereby improving heat storage efficiency. [Means for solving the problem]

[0006] As a result of thorough investigation into the above problems, the inventors discovered that in a chemical heat storage device, the heat storage efficiency can be improved by providing a heat reflective member that suppresses radiation between the storage container and the chemical heat storage material, and thus completed the present invention. That is, the present invention relates to the following chemical heat storage device.

[0007] In order to solve the above problems, the chemical heat storage device of the present invention is a chemical heat storage device which, during heat storage, heats a heat storage medium to separate it into a heat storage product and a produced fluid, and, during heat release, reacts the heat storage product with a reactive fluid to produce the heat storage medium, and is characterized in that it comprises the heat storage medium, a heat exchange section through which a heat transfer fluid passes and which exchanges heat between the heat storage medium and the heat transfer fluid, and a storage container which contains the heat storage medium and the heat exchange section and has a supply port for supplying the heat transfer fluid from the outside to the heat exchange section, and a discharge port for discharging the heat transfer fluid that has exchanged heat with the heat storage medium to the outside, and a first heat reflecting member is provided between the heat storage medium and the storage container, and the first heat reflecting member is arranged at a distance from the inner wall of the storage container.

[0008] According to this chemical heat storage device, the radiant heat generated by heat exchange from the heat storage medium can be returned to the heat storage medium by the first heat reflecting member. In addition, by disposing the first heat reflecting member away from the inner wall of the storage container, the absorption of the radiant heat by the storage container is suppressed, and an air layer is formed between the first heat reflecting member and the storage container, thereby obtaining a further heat insulating effect.

[0009] Furthermore, in one embodiment of the chemical heat storage device of the present invention, the first heat reflecting member has a first ventilation part. In chemical heat storage, which requires the bonding and desorption of the chemical heat storage material and the product / reaction fluid, it is desirable to increase the degree of freedom of movement of the gas after the reaction while at the same time providing heat insulation. With this feature, a path for the product fluid after the reaction is formed, making it possible to separate the heat storage medium and the product gas.

[0010] Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that the first ventilation portion of the first heat reflecting member is a slit or a hole formed in the first heat reflecting member. According to this feature, a movement path for the product fluid after the reaction can be formed with a simple structure.

[0011] Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that a second heat reflecting member is provided between the first heat reflecting member and the storage container, and the second heat reflecting member is arranged at a distance from both the first heat reflecting member and the inner wall of the storage container. According to this feature, the radiant heat emitted from the first heat reflecting member and the first ventilation portion can be returned to the heat storage medium side by the second heat reflecting member, thereby further improving the heat shielding effect.

[0012] Furthermore, one embodiment of the chemical heat storage device of the present invention is characterized in that the second heat reflecting member has a second ventilation portion, and the second ventilation portion is arranged so as not to overlap with the first ventilation portion of the first heat reflecting member. According to this feature, the radiant heat emitted from the first ventilation part can be returned to the heat storage medium side by the second heat reflecting member without passing through the second ventilation part, thereby further improving the heat shielding effect. Effect of the Invention

[0013] According to the chemical heat storage device of the present invention, it is possible to suppress the release of heat to the storage container due to radiation from the heat storage medium held in the storage container during heat storage, thereby improving the heat storage efficiency. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic explanatory diagram showing a structure of a chemical heat storage device according to a first embodiment of the present invention. [Diagram 2] FIG. 4 is a schematic explanatory diagram showing the structure of a chemical heat storage device according to a second embodiment of the present invention. [Diagram 3] FIG. 11 is a schematic explanatory diagram showing the structure of a chemical heat storage device according to a third embodiment of the present invention. [Figure 4] FIG. 11 is a schematic explanatory diagram showing the structure of a chemical heat storage device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0016] [Chemical heat storage device] The chemical heat storage device of the present invention is a chemical heat storage device that, during heat storage, heats the heat storage medium to separate it into a heat storage product and a produced fluid, and, during heat release, reacts the heat storage product with a reactive fluid to produce the heat storage medium.The device is capable of storing waste heat generated from factories, waste incineration plants, etc. in the heat storage medium and transporting it to areas where heat is needed.

[0017] The heat storage device of the present invention is configured to include a heat storage medium, a heat exchange section through which a heat transfer fluid passes and which exchanges heat between the heat storage medium and the heat transfer fluid, and a storage container that houses the heat storage medium and the heat exchange section and has a supply port for supplying the heat transfer fluid from the outside to the heat exchange section, and a discharge port for discharging the heat transfer fluid that has exchanged heat with the heat storage medium to the outside, and a first heat reflecting member that is arranged between the heat storage medium and the storage container and spaced apart from the inner wall of the storage container.

[0018] First embodiment 1 is a schematic explanatory diagram showing the structure of a heat storage device 1a according to a first embodiment of the present invention. The heat storage device 1a includes a storage container 2 that stores a heat storage medium 4 and a holding member 5 that holds the heat storage medium 4. The storage container 2 is provided with a heat exchange section 3 inside which a heat transfer fluid from the outside passes and exchanges heat with the heat storage medium 4. The storage container 2 is also provided with a fluid supply port 8 for supplying the heat transfer fluid from the outside and a fluid discharge port 9 for discharging the heat transfer fluid to the outside. Furthermore, a first heat reflecting member 6 is disposed between the storage container 2 and the holding member 5, spaced apart from the inner wall of the storage container 2. Each component will be described in detail below.

[0019] (heat storage medium) The heat storage medium 4 is a chemical substance that is separated into a heat storage product and a generated fluid when heated, and releases heat by the reverse reaction. For example, calcium oxide (CaO) and water vapor (H 2 O), calcium chloride (CaCl 2 ) and water vapor (H 2 O), calcium bromide (CaBr 2 ) and water vapor (H 2 O), calcium iodide (CaI 2 ) and water vapor (H 2 O), magnesium oxide (MgO) and water vapor (H 2 O), magnesium chloride (MgCl 2 ) and water vapor (H 2 O), zinc chloride (ZnCl 2 ) and water vapor (H 2 O), strontium chloride (SrCl 2) and ammonia (NH 3 ), Strontium bromide (SrBr 2 ) and ammonia (NH 3 ), calcium oxide (CaO) and carbon dioxide (CO 2 ), magnesium oxide (MgO) and carbon dioxide (CO 2 From the viewpoint of ease of handling, it is preferable that the heat storage medium 4 uses water vapor as the product fluid and the reactant fluid. In addition, since the chemical heat storage device of the present invention is configured to be particularly effective when chemically storing heat at high temperatures, it is preferable to use, as the heat storage medium 4 of the present invention, a combination of calcium oxide and water vapor (400 to 500 degrees) or a combination of magnesium oxide and water vapor (300 to 400 degrees) as the heat storage product and product fluid capable of chemically storing heat at high temperatures.

[0020] The structure and shape of the heat storage medium 4 in the present invention are not particularly limited, and may be a powder, a compact formed from powder, or the heat storage medium 4 supported on a porous body.

[0021] The structure of the holding member 5 for holding the heat storage medium 4 is not particularly limited as long as it is a structure that holds the heat storage medium 4 in the storage container 2 and enables heat exchange between the heat storage medium 4 and the heat exchange section 3. Although Fig. 1 shows an example of a structure in which the heat storage medium 4 is stored in one container, the present invention is not limited thereto, and for example, a configuration in which a plurality of box-shaped containers or tray-shaped containers storing the heat storage medium 4 are stacked may be used. Furthermore, the material of the holding member 5 is not particularly limited as long as it can withstand high-temperature treatment.

[0022] (Storage container) The storage container 2 is configured to store the heat storage medium 4 and is made of a sealable structure. The storage container 2 has a heat exchange section 3 through which a fluid passes for transferring heat between the heat storage medium 4 stored therein and the outside, a fluid supply port 8 for supplying a heat transfer fluid from the outside for performing heat exchange to the heat exchange section 3, and a fluid discharge port 9 for discharging the fluid from the heat exchange section 3.

[0023] The heat exchange section 3 may be of any shape as long as it can transfer heat between the heat storage medium 4 stored inside the holding member 5 and a heat transfer fluid from the outside. For example, it may be composed of a heat exchange tube arranged in a serpentine manner inside the holding member 5, or a double cylindrical inner tube portion for the holding member 5.

[0024] The fluid supply port 8 and the fluid discharge port 9 may be arranged on different surfaces of the storage container 2, or on the same surface. For example, as shown in Fig. 1, the fluid supply port 8 may be provided on the lower part of the storage container 2 and the fluid discharge port 9 may be provided on the upper part of the storage container 2 along the central axis of the storage container 2. In addition, by providing the fluid supply port 8 and the fluid discharge port 9 on the same surface of the storage container 2 and supplying and discharging the fluid on one surface, the structure of the heat storage device 1a as a whole becomes compact, and therefore it becomes possible to expand the options for the installation location of the heat storage device 1.

[0025] The storage container 2 is also provided with an air opening 10 for discharging the product fluid generated from the heat storage medium 4 during heat storage to the atmosphere, and an air supply port 11 for supplying a reaction fluid that reacts with the heat storage product during heat dissipation. In the heat storage device 1a of the first embodiment, the air opening 10 and the air supply port 11 use the same vent port, but they may be provided at different positions.

[0026] The air vent 10 is opened during heat storage and is configured to discharge the produced fluid generated from the heat storage medium 4 to the outside of the storage container 2, but a liquid receiving tank for coagulating and recovering the produced fluid may also be provided. By providing the air vent 10, the produced fluid is discharged to the outside, eliminating the need to provide a liquid receiving tank for coagulating and recovering the produced fluid, and eliminating the need to transport the produced fluid from the heat supply area to the heat demand area. This has the advantages of making the device more compact and reducing transportation costs.

[0027] The air supply port 11 is opened during heat dissipation to supply the reaction fluid to the storage container 2, and is connected to a supply unit (not shown) for supplying the reaction fluid during heat dissipation.

[0028] The heat transfer fluid is preferably a fluid such as a gas or liquid, as long as it has a temperature that can supply heat to the heat storage medium 4. Furthermore, from the viewpoint of ease of handling, it is particularly preferable to use a gas.

[0029] (First heat reflecting member) The first heat reflecting member 6 is provided between the storage container 2 and the heat storage medium 4 and is disposed at a distance from the inner wall of the storage container 2 .

[0030] The first heat reflecting member 6 is configured to reflect the radiant heat emitted from the holding member 5 that holds the heat storage medium 4 during heat storage back toward the heat storage medium 4. By providing the first heat reflecting member 6, it becomes possible to suppress the absorption of radiant heat into the storage container 2, improving the heat storage effect. In addition, by arranging the first heat reflecting member 6 away from the inner wall of the storage container 2, an air layer is formed between the first heat reflecting member 6 and the storage container 2, and an even more insulating effect is obtained.

[0031] The specific structure of the first heat reflecting member 6 is not particularly limited as long as it is a structure for reflecting the radiant heat emitted from the holding member 5 toward the heat storage medium 4, and may be, for example, a box-shaped structure that surrounds the entire holding member 5, or a cylindrical structure arranged to surround the periphery of the holding member 5, as shown in Fig. 1. The first heat reflecting member 6 may also be a combination of a cylindrical structure that surrounds the periphery of the holding member 5 and a structure that covers either the top or bottom of the holding member 5. Furthermore, the first heat reflecting member 6 may have a structure having a curved surface so that heat is effectively collected toward the heat storage medium 4.

[0032] The first heat reflecting member 6 is made of a material capable of reflecting radiant heat. Examples of such materials include metals such as aluminum, iron, copper, brass, silver, gold, platinum, nickel, stainless steel, chromium, and tungsten. Examples of non-metals include quartz glass, alumina ceramics, magnesia ceramics, and fireproof bricks.

[0033] In addition, it is desirable to select the first heat reflecting member 6 in the present invention taking into consideration the emissivity of the material. Due to the relationship of reflectivity = 1 - emissivity, the lower the emissivity, the higher the reflectivity of the material. Emissivity is a value defined in JIS Z 8117 as the ratio of the radiant emittance of a radiator to the radiant emittance of a black body at the same temperature as the radiator, and the measured emissivity is obtained by, for example, spectral emissivity measurement using FTIR as specified in JIS R 1801. Note that emissivity is a parameter that depends on temperature. The emissivity of a material also depends on the surface condition of the material. The less uneven the surface, the lower the emissivity. Therefore, particularly for metal materials, a polished surface is more preferable than an oxidized or rough surface. The first heat reflecting member 6 in the present invention is made of a material having an emissivity of 0.5 or less, more preferably 0.1 or less, and even more preferably 0.05 or less, at the temperature during heat storage.

[0034] [Other aspects of the heat storage device] Another embodiment of the heat storage device will be exemplified below. Second embodiment FIG. 2 is a schematic explanatory diagram showing the structure of a heat storage device 1b according to a second embodiment of the present invention. This heat storage device 1b is configured such that a first ventilation part 61 is provided on the first heat reflecting member 6 in the heat storage device 1a of the first embodiment. In chemical heat storage that requires bonding and desorption of the chemical heat storage material and the product / reaction fluid, it is desirable to increase the degree of freedom of gas movement while at the same time providing heat insulation. According to this heat storage device 1b, a movement path for the product fluid after reaction is formed, so that the heat storage medium and the product fluid are efficiently separated, and the heat exchange efficiency can be improved.

[0035] In the heat storage device 1b of the second embodiment, the first ventilation portion 61 can be provided in the first heat reflection member 6 by arranging a plurality of plate-like members in a louver shape as shown in FIG. 2, or by opening slits or holes as ventilation openings in the plate-like members. In particular, it is preferable that the first ventilation portion 61 in the present invention is configured by providing a ventilation hole in a plate-shaped member. With this configuration, it is possible to induce separation of the product fluid from the heat storage medium with a simple configuration.

[0036] [Third embodiment] FIG. 3 is a schematic explanatory diagram showing the structure of a heat storage device 1c according to a third embodiment of the present invention. This heat storage device 1c is configured such that in the heat storage device 1b of the first embodiment, a second heat reflecting member 7 is provided outside the first heat reflecting member 6, and the second heat reflecting member 7 is disposed at a distance from the inner wall of the storage container 2 and the first heat reflecting member 6. According to this heat storage device 1c, the radiant heat emitted through the first heat reflecting member 6 or the radiant heat emitted from the first ventilation section 61 can also be reflected toward the heat storage medium 4, thereby further improving the heat storage effect.

[0037] The specific structure of the second heat reflecting member 7 is not particularly limited as long as it is configured to reflect the radiant heat emitted from the holding member 5 toward the heat storage medium 4, similarly to the above-mentioned first heat reflecting member 6, and may be, for example, a box-shaped structure surrounding the entire holding member 5 or a cylindrical structure arranged to surround the periphery of the holding member 5. The second heat reflecting member 7 may also be configured by combining a cylindrical structure surrounding the periphery of the holding member 5 with a structure covering either the top or bottom of the holding member 5. Furthermore, the second heat reflecting member 7 may have a structure having a curved surface so that heat is effectively collected toward the heat storage medium 4.

[0038] The second heat reflecting member 7 is made of a material capable of reflecting radiant heat. Examples of such materials include metals such as aluminum, iron, copper, brass, silver, gold, platinum, nickel, stainless steel, chromium, and tungsten. Examples of non-metals include quartz glass, alumina ceramics, magnesia ceramics, and fireproof bricks.

[0039] Moreover, it is desirable to select the material for the second heat reflecting member 7 in the present invention in consideration of the emissivity of the material. The second heat reflecting member 7 in the present invention is made of a material having an emissivity of 0.5 or less, more preferably 0.1 or less, and even more preferably 0.05 or less, at the temperature during heat storage. The second heat reflecting member 7 and the first heat reflecting member 6 may be made of the same material or different materials.

[0040] [Fourth embodiment] FIG. 4 is a schematic explanatory diagram showing the structure of a heat storage device 1d according to a fourth embodiment of the present invention. This heat storage device 1d is configured such that in the heat storage device 1c of the third embodiment, a second ventilation part 71 is provided in the second heat reflecting member 7. According to this heat storage device 1d, a movement path for the product fluid after the reaction is formed in both of the two heat reflecting members, so that the heat storage medium and the product fluid can be efficiently separated, and the heat exchange efficiency can be improved.

[0041] In the heat storage device 1d of the fourth embodiment, the second heat reflection member 7 is provided with the second ventilation portion 71, which may be configured by arranging a plurality of plate-like members in a louver shape, or by opening slits or holes as ventilation openings in the plate-like members as shown in FIG. 4. In addition, it is particularly preferable that the second ventilation part 71 in the present invention has a structure and arrangement that does not overlap with the first ventilation part 61, as shown in Fig. 4. This structure allows the radiant heat emitted from the first ventilation part 61 to be returned to the heat storage medium 4 side by the second heat reflecting member 7 without passing through the second ventilation part 71 as it is, and therefore the heat shielding effect can be further improved. [Industrial Applicability]

[0042] The chemical heat storage device of the present invention is used in a method for effectively utilizing waste heat generated from factories, waste incineration plants, etc. For example, the chemical heat storage device of the present invention is used in a method for storing heat in a heat supply area where waste heat is generated, and transporting the heat storage device to a heat demand area where heat is required and dissipating the heat. It can also be used in a method for storing heat during the hours when waste heat is generated and dissipating heat during the hours when heat is required at the same installation location, such as storing heat during the day and dissipating heat at night. [Explanation of symbols]

[0043] Reference Signs List 1a, 1b, 1c, 1d...chemical heat storage device, 2...storage container, 3...heat exchange section, 4...heat storage medium, 5...holding member, 6...first heat reflecting member, 61...first ventilation section, 7...second heat reflecting member, 71...second ventilation section, 8...fluid supply port, 9...fluid discharge port, 10...atmospheric opening port, 11...air supply port

Claims

1. A chemical heat storage device that, during heat storage, heats a heat storage medium to separate it into a heat storage product and a product fluid, and, during heat release, reacts the heat storage product with a reaction fluid to generate the heat storage medium, The heat storage medium; a heat exchange section through which a heat transfer fluid passes to exchange heat between the heat storage medium and the heat transfer fluid; a storage container that stores the heat storage medium and the heat exchange unit, a first heat reflecting member is provided between the heat storage medium and the storage container; the first heat reflecting member is disposed apart from the heat storage medium, and a shielding range of the first heat reflecting member is fixed; The chemical heat storage device, wherein the first heat reflecting member is disposed at a distance from an inner wall of the storage container.

2. A chemical heat storage device which, during heat storage, heats a heat storage medium to separate it into a heat storage product and a generated fluid, and, during heat release, reacts the heat storage product with a reactive fluid to generate the heat storage medium, The heat storage medium; a heat exchange section through which a heat transfer fluid passes to exchange heat between the heat storage medium and the heat transfer fluid; a storage container that stores the heat storage medium and the heat exchange unit, a first heat reflecting member is provided between the heat storage medium and the storage container; the first heat reflecting member is disposed apart from the heat storage medium, and a shielding range of the first heat reflecting member is fixed; The chemical heat storage device, wherein the first heat reflecting member has a first ventilation portion, and an opening area of ​​the first ventilation portion is fixed.

3. The chemical heat storage device according to claim 2 , wherein the first ventilation portion is a slit or a hole formed in the first heat reflecting member.

4. A chemical heat storage device according to any one of claims 1 to 3, characterized in that a second heat reflecting member is provided between the first heat reflecting member and the storage container, and the second heat reflecting member is disposed at a distance from both the first heat reflecting member and the inner wall of the storage container.

5. The first heat reflecting member has a first ventilation portion, The chemical heat storage device according to claim 4, characterized in that the second heat reflecting member has a second ventilation portion, and the second ventilation portion is arranged so as not to overlap with the first ventilation portion of the first heat reflecting member.

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