Cold storage material

Abstract

A cold storage material according to the present disclosure comprises: at least one salt which is selected from the group consisting of a carboxylic acid tetra-n-butyl ammonium salt and a carboxylic acid tetra-n-butyl phosphonium salt; water; a porous substance; a silver compound; and an alcohol. The salt contains an anionic atomic group that has two or more oxygen atoms. The alcohol contains at least one selected from the group consisting of a monohydric alcohol having 3 to 5 carbon atoms and a dihydric alcohol having 3 to 6 carbon atoms. The molar ratio of the content of the alcohol to the content of the salt is 0.1 to 0.9%.

Description

Cold storage material

[0001] The present disclosure relates to a regenerator material.

[0002] Patent Document 1 relates to a supercooling removal device for an ice thermal storage device or the like used in air conditioning of buildings or in the production or processing of food that is cooled or refrigerated at ice temperature.

[0003] Patent Document 2 relates to a heat storage agent used in air conditioning equipment such as heaters and coolers or cooling equipment for food, etc., and a method for preparing the heat storage agent.

[0004] Japanese Patent Laid-Open No. 5-187673 Japanese Patent Laid-Open No. 2007-246778

[0005] The present disclosure provides a cold storage material that is advantageous from the viewpoint of enabling cold storage with low power consumption and long-term cold storage by storing cold for a limited time.

[0006] The cold storage material of the present disclosure comprises: at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts; water; a porous substance; a silver compound; and an alcohol, wherein the salt contains an anionic atomic group having two or more oxygen atoms; the alcohol contains at least one selected from the group consisting of monohydric alcohols having 3 to 5 carbon atoms and dihydric alcohols having 3 to 6 carbon atoms; and the molar ratio of the alcohol content to the salt content is 0.1 to 0.9%.

[0007] The cold storage material of the present disclosure is capable of rapid cold storage with a small degree of supercooling, and can ensure a large amount of cold storage in a specified cold storage time. As a result, the cold storage material of the present disclosure is advantageous in that it can store cold with low power consumption while storing cold for a limited time to enable long-term cold retention.

[0008] Graph showing the characteristics of the cold storage material when it is released into the cold according to the first embodiment. FIG.

[0009] (Knowledge, etc., that Formed the Basis of the Present Disclosure) At the time the present inventors arrived at the present disclosure, certain requirements existed for cold storage under narrow operating temperature ranges in applications such as food production or processing processes and air conditioning systems. Examples of narrow operating temperature ranges include cold storage at approximately 5°C and cold release at approximately 11°C. For example, when a semi-clathrate hydrate-based cold storage material is used for such cold storage, it may be required that supercooling be released and crystallization be completed at a small degree of supercooling. However, in large-scale cold storage systems, heat exchange requires time. For this reason, there was a problem that a small degree of supercooling would result in insufficient crystal growth rate for cold storage in a large amount of cold storage material, and cold storage would not be completed within the specified time. Therefore, the industry believed that it would be difficult to use a large amount of semi-clathrate hydrate-based cold storage material for applications requiring cold storage under the above-mentioned narrow operating temperature range.

[0010] Under these circumstances, the present inventors have been researching day and night for additives that can promote crystal growth in a specific cold storage material that stores cold through the crystal growth of semiclathrate hydrate. During this research, the present inventors have newly discovered that a combination of a porous substance, a silver compound, and a specific alcohol can promote crystal growth, which constitutes the subject of the present disclosure.

[0011] Therefore, the present disclosure provides an advantageous cold storage material that contains at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts, and that enables cold storage with low power consumption while storing cold for a limited period of time, thereby enabling long-term cold storage.

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially identical configurations may be omitted. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0013] (First Embodiment) Hereinafter, a first embodiment will be described with reference to FIG.

[0014] [1-1. Configuration] The cold storage material in embodiment 1 includes at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts, water, a porous substance, a silver compound, and an alcohol. The salt includes an anionic atomic group having two or more oxygen atoms. The alcohol includes at least one selected from the group consisting of monohydric alcohols having 3 to 5 carbon atoms and dihydric alcohols having 3 to 6 carbon atoms. In the cold storage material, the molar ratio of the alcohol content to the salt content is 0.1 to 0.9%.

[0015] Semiclathrate hydrate is formed during cold storage in a cold storage material. In this specification, clathrate hydrate refers to a crystal formed when water molecules, which are host molecules, form cage-like crystals through hydrogen bonds, and a guest substance, which is a substance other than water, is enclosed within the cage-like crystal. In addition, semiclathrate hydrate is a crystal formed when a guest substance participates in the hydrogen bond network of water molecules. The concentration at which water molecules and guest substance form a hydrate in just the right amount is called the congruent concentration. In cold storage materials in which clathrate hydrate and semiclathrate hydrate are formed, the concentration of the guest substance in the cold storage material can be adjusted to the congruent concentration or close to the congruent concentration.

[0016] The regenerator material has a predetermined melting point, which can be measured using a differential scanning calorimeter (DSC), as is well known in the regenerator material art.

[0017] FIG. 1 is a graph showing the characteristics of a pre-crystallized cold storage material when it is released to cool. In FIG. 1, the horizontal and vertical axes represent time t and temperature T, respectively. In section E of FIG. 1, the temperature of the cold storage material is maintained at a temperature below the crystallization temperature. For example, the cold storage material is placed inside a cold storage tank, and a refrigerant is stored around the cold storage material inside the cold storage tank. The temperature of the refrigerant stored around the cold storage material is adjusted to a temperature below the crystallization temperature so that the temperature of the cold storage material is maintained at a temperature below the crystallization temperature. The refrigerant is, for example, water.

[0018] Next, a high-temperature refrigerant is supplied into the cold storage tank, gradually warming the cold storage material (see section F in Fig. 1). For example, when a high-temperature refrigerant is supplied into the cold storage tank at the end of section E, i.e., the beginning of section F, the temperature around the cold storage material gradually increases.

[0019] When the temperature of the cold storage material reaches its melting point Tm, the temperature of the cold storage material is maintained near the melting point Tm. See section G in Figure 1. If there is no cold storage material in the cold storage tank, the temperature of the refrigerant stored in the cold storage tank will continuously rise as shown in section Z in Figure 1. On the other hand, if there is cold storage material in the cold storage tank, the temperature of the refrigerant stored in the cold storage tank will be maintained near the melting point Tm of the cold storage material in section G. In this way, the cold storage material exerts its cold storage effect. At the end of section G, the crystals in the cold storage material melt and disappear. As a result, the cold storage material liquefies. It can be understood that the longer the time in section G during which the temperature of the cold storage material is maintained near the melting point Tm, the higher the cold release performance of the cold storage material.

[0020] Thereafter, the temperature of the liquefied regenerator material rises to become equal to the temperature of the high-temperature refrigerant supplied into the regenerator tank (see section H in FIG. 1).

[0021] The regenerator material can be cooled and reused.

[0022] The cold storage material satisfies, for example, the following conditions (I) and (II). When the cold storage material satisfies these conditions, it can be advantageously used in food production or food processing processes, or in air conditioning for cooling. Condition (I): The cold storage material can store cold at a temperature of about 5°C or higher. Condition (II): The cold storage material can release cold using latent heat at about 11°C, and has a latent heat amount of 165 kJ / kg or higher.

[0023] Regarding condition (I), for example, in a food production or processing process or an air conditioning system for cooling, the temperature at which a refrigerant cooled in a refrigerator using late-night power is supplied to a cold storage tank to crystallize the cold storage material and store cold is approximately 5°C. If the set temperature of the refrigerator is below 5°C, there is a possibility that the refrigerant will freeze due to variations in the operating conditions of the refrigerator. It is desirable to satisfy condition (I) from the viewpoint of preventing the refrigerant from freezing.

[0024] Regarding condition (II), in food production or processing processes or air conditioning systems, cooling must occur at a temperature of approximately 11°C. For example, a refrigerant that stores cold energy using latent electricity during the day passes through a circulation path between the cold storage tank and the object to be cooled and returns to the cold storage tank at a temperature of approximately 11°C or higher. Since a cold storage material must cool such a cold storage material, it is important that it be capable of releasing cold using latent heat at approximately 11°C. For example, the melting point of n-pentadecane is 9.9°C, and the amount of latent heat associated with the melting of n-pentadecane is 164 kJ / kg. Therefore, when condition (II) is satisfied, a cold storage material is likely to be superior in terms of cold storage performance to a cold storage material containing n-pentadecane.

[0025] Thus, according to the cold storage material of the present disclosure, the difference between the cold storage temperature and the cold release temperature can be adjusted to approximately 6°C. Considering the inevitable supercooling of the cold storage material, the melting point of the cold storage material can be set to a temperature 1°C lower than the cold release temperature according to the usage conditions. It is also important that the cold storage temperature is at least 5°C lower than the melting point of the cold storage material. If the cold storage temperature needs to be adjusted to be lower than the melting point of the cold storage material by more than 5°C, the power consumption of the refrigerator will increase, which is not advantageous from the perspective of energy conservation.

[0026] In the art, the heat of fusion is also called the latent heat.

[0027] In the salt of the cold storage material, the anionic atomic group is not limited to a specific atomic group as long as it has two or more oxygen atoms. The anionic atomic group is, for example, a carboxylic acid (carboxylate ion) having six or fewer carbon atoms. The anionic atomic group may include 2-ethylbutanoate. In this case, the cold storage material is likely to satisfy the above conditions (I) and (II).

[0028] In the cold storage material, the ratio of the salt content to the water content is not limited to a specific value. This ratio is, for example, 2% or more and 4% or less on a molar basis. When the water and tetra-n-butylammonium carboxylate salt or the water and tetra-n-butylphosphonium carboxylate salt form a semiclathrate hydrate in the cold storage material in an adequate amount, the melting point and latent heat of the cold storage material can be maximized. The salt concentration when the water and salt form a semiclathrate hydrate in an adequate amount is also called the congruent concentration. When the ratio of the salt content to the water content is 2% or more and 4% or less on a molar basis, the salt concentration in the cold storage material is easily adjusted to the congruent concentration or close to the congruent concentration.

[0029] The porous material is not limited to a specific porous material. Clusters of regularly arranged water molecules derived from semiclathrate hydrate generated during cold storage tend to remain in the pores of the porous material even after the cold storage material is exposed to cold. During cold storage after exposure to cold, semiclathrate hydrate tends to be generated starting from these clusters.

[0030] The porous material includes, for example, activated carbon, which is available at a relatively low cost and can reduce the manufacturing cost of the regenerator material.

[0031] Activated carbon has, for example, a basic surface. For example, activated carbon removed from a regenerator material is washed and then dispersed in pure water. If the pH of the dispersion is basic, it can be determined that the activated carbon has a basic surface.

[0032] The activated carbon may be, for example, one that dissolves at least one element selected from the group consisting of Na and K into the water of the cold storage material. The activated carbon may be, for example, one that dissolves at least one element selected from the group consisting of Na and K into the pure water when dispersed in pure water.

[0033] The porous substance may be a carbon-based porous material other than activated carbon, such as mesoporous carbon.

[0034] The cold storage material may contain dissolved Na. The concentration of Na dissolved in the cold storage material is not limited to a specific value. The concentration is, for example, 3 mg / L or more. At least a portion of the Na dissolved in the cold storage material may be derived from activated carbon, which is a porous material.

[0035] The cold storage material may contain dissolved potassium. The concentration of potassium dissolved in the cold storage material is not limited to a specific value. The concentration is, for example, 20 mg / L or more. At least a portion of the potassium dissolved in the cold storage material may be derived from activated carbon, which is a porous material.

[0036] The content of the porous substance in the regenerator material is not limited to a specific value. The content is, for example, 2 mass % or less. In this case, the condition (II) is more likely to be satisfied.

[0037] In the regenerator material, the size of the porous substance is not limited to a specific value. The porous substance may contain particles having a maximum diameter of, for example, 1 mm or more. The porous substance may also contain particles having a maximum diameter of less than 1 mm.

[0038] The porous material may be, for example, submerged in the liquid regenerator material, or a portion of the porous material may be suspended in the liquid regenerator material.

[0039] The silver compound in the regenerator material is not limited to a specific compound, and may include, for example, at least one selected from the group consisting of AgO, AgO, AgCO, AgPO, AgF, AgSO, AgCrO, AgWO, and a silver carboxylate having 5 or less carbon atoms.

[0040] The content of the silver compound in the regenerator material is not limited to a specific value, and the ratio of the content of the silver compound to the content of the salt is, for example, 0.05% or more and 0.10% or less on a molar basis.

[0041] The alcohol in the regenerator material is not limited to a specific alcohol, as long as it includes at least one selected from the group consisting of monohydric alcohols having 3 to 5 carbon atoms and dihydric alcohols having 3 to 6 carbon atoms. The number of carbon atoms in the monohydric alcohol may be 3 to 4, and the number of carbon atoms in the dihydric alcohol may be 3 to 4. The alcohol preferably includes at least one selected from the group consisting of 1-propanol, iso-propanol, 1,3-propanediol, 1-butanol, 2-butanol, 1,4-butanediol, 1-pentanol, and 1,6-hexanediol.

[0042] The molar ratio of the alcohol content to the salt content in the regenerator material may be 0.1 to 0.8%, 0.1 to 0.7%, or 0.1 to 0.6%.

[0043] The cold storage material may further contain additives other than the above-mentioned salt, water, porous substance, silver compound, and alcohol. Examples of the additives include a supercooling inhibitor, a thickener, and a preservative.

[0044] The cold accumulator may not contain any additives, that is, the cold accumulator may be composed only of the above salt, water, a porous substance, a silver compound, and the above alcohol.

[0045] The cold storage material can be produced by mixing the above salt, water, a porous substance, a silver compound, and the above alcohol.

[0046] [1-2. Operation] The operation and function of the regenerator material in the first embodiment will be described.

[0047] When using a cold storage material, the material is repeatedly cooled and then allowed to cool. During the cold storage, crystals of the semiclathrate hydrate of the salt can be formed at a small degree of supercooling. Crystallization can be completed quickly at a temperature slightly below the melting point of the semiclathrate hydrate of the salt.

[0048] Upon cooling, decomposition of the semiclathrate hydrate of the salt occurs. Therefore, upon cooling, most of the semiclathrate hydrate of the salt having a low melting point is likely to decompose at a temperature slightly higher than the melting point of the semiclathrate hydrate of the salt. For example, 85% or more of the semiclathrate hydrate of the salt can decompose at a temperature 1° C. higher than the melting point of the semiclathrate hydrate of the salt.

[0049] [1-3. Effects, etc.] As described above, in this embodiment, the cold storage material includes at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts, water, a porous substance, a silver compound, and an alcohol. The salt includes an anionic atomic group having two or more oxygen atoms. The alcohol includes at least one selected from the group consisting of monohydric alcohols having 3 to 5 carbon atoms and dihydric alcohols having 3 to 6 carbon atoms. In the cold storage material, the molar ratio of the alcohol content to the salt content is 0.1 to 0.9%.

[0050] The cold storage material of the present disclosure is capable of rapid cold storage with a small degree of supercooling, and can ensure a large amount of cold storage in a specified cold storage time. As a result, the cold storage material of the present disclosure is advantageous in that it can store cold with low power consumption while storing cold for a limited time to enable long-term cold retention.

[0051] As in this embodiment, the alcohol may include at least one selected from the group consisting of 1-propanol, iso-propanol, 1,3-propanediol, 1-butanol, 2-butanol, 1,4-butanediol, 1-pentanol, and 1,6-hexanediol. In this case, rapid cold storage with a small degree of supercooling is more easily achieved, and a large amount of cold storage is more easily secured within a specified cold storage time.

[0052] As in this embodiment, the porous material may contain activated carbon, which is inexpensive and therefore tends to reduce the manufacturing cost of the regenerator material.

[0053] As in this embodiment, the activated carbon may have a basic surface, in which case crystals of semiclathrate hydrates of the above salts are more likely to form even at a small degree of supercooling.

[0054] As in the present embodiment, the activated carbon may be such that at least one element selected from the group consisting of Na and K is eluted into the water of the cold storage material. In this case, crystals of semiclathrate hydrate of the above salt are more likely to be generated at a small degree of supercooling.

[0055] As in the present embodiment, the regenerator material may have 3 mg / L or more of Na dissolved therein, in which case the crystals of the semiclathrate hydrate of the salt are more likely to be formed at a small degree of supercooling.

[0056] As in this embodiment, the regenerator material may have 20 mg / L or more of dissolved K. In this case, crystals of the semiclathrate hydrate of the salt are more likely to be formed at a small degree of supercooling.

[0057] As in this embodiment, the anionic atomic group may be a carboxylic acid (carboxylate ion) having six or fewer carbon atoms. In this case, the melting point of the semiclathrate hydrate crystals of tetra-n-butylammonium salt or tetra-n-butylphosphonium salt is easily adjusted to about 10°C or less. In this case, semiclathrate hydrate crystals are more likely to be formed at a small degree of supercooling. This enables rapid cold storage at a small degree of supercooling, making it easier to ensure a large amount of cold storage for a specified cold storage time. This is advantageous from the perspective of enabling cold storage with low power consumption while enabling long-term cold storage by storing cold in a limited time.

[0058] As in this embodiment, the anionic atomic group may be 2-ethylbutanoate. In this case, the decomposition temperatures of the semiclathrate hydrates of tetra-n-butylammonium carboxylate and tetra-n-butylphosphonium carboxylate are approximately 9.9°C and approximately 8.3°C, respectively. In addition, the latent heats of the semiclathrate hydrates of tetra-n-butylammonium carboxylate and tetra-n-butylphosphonium carboxylate are approximately 200 kJ / kg and approximately 195 kJ / kg, respectively. In this case, semiclathrate hydrate crystals are more likely to be formed with a small degree of supercooling. In addition, the amount of latent heat that can be stored as cold energy in the cold storage material is likely to be large. This is advantageous from the viewpoint of enabling cold storage with low power consumption while enabling long-term cold storage by storing cold for a limited time.

[0059] As in this embodiment, the silver compound may contain at least one selected from the group consisting of AgO, AgO, AgCO, AgPO, AgF, AgSO, AgCrO, AgWO, and silver carboxylates having five or fewer carbon atoms. In this case, semiclathrate hydrate crystals of the above salts are more likely to form at low supercooling degrees. This allows for rapid cold storage at low supercooling degrees, making it easier to ensure a large amount of cold storage for a given cold storage time. This is advantageous from the perspective of enabling cold storage with low power consumption while enabling long-term cold storage by storing cold for a limited time.

[0060] Second Embodiment Hereinafter, a second embodiment will be described with reference to FIG.

[0061] FIG. 2 shows a cold energy storage system 1a according to the second embodiment.

[0062] The cold storage system 1a includes a cold storage tank 10, a refrigerator 20, a cooling target 30, a first circulation path 22, and a second circulation path 32. A refrigerant 11 is stored inside the cold storage tank 10. The refrigerant 11 is, for example, water. The cold storage tank 10 can be placed, for example, in a food factory or the basement of a building. A plurality of cold storage modules 12 are arranged inside the cold storage tank 10. The plurality of cold storage modules 12 are immersed in the refrigerant 11. The cold storage module 12 includes, for example, a resin container having a rectangular parallelepiped outer shape and the above-mentioned cold storage material housed inside the container. The thickness of the plate material forming the container is, for example, 3 mm or less. The cold storage material housed inside the container of the cold storage module 12 has, for example, a thickness of 20 mm or less in a solid state.

[0063] 2, a plurality of cases 14 are arranged inside the cold storage tank 10. Inside the cases 14, a plurality of cold storage modules 12 are arranged at predetermined intervals.

[0064] The first circulation path 22 is disposed between the refrigerator 20 and the cold storage tank 10. For example, a pump (not shown) is disposed in the first circulation path 22. During cold storage operation of the cold storage system 1a, operation of the pump causes the refrigerant 11 to circulate between the refrigerator 20 and the cold storage tank 10 through the first circulation path 22, as indicated by the solid arrows in Fig. 2. Heat exchange between the refrigerant 11 cooled by the refrigerator 20 and the cold storage module 12 crystallizes the cold storage material inside the cold storage module 12, and latent heat is stored as cold energy. During cold storage operation of the cold storage system 1a, the refrigerator 20 is operated, for example, using latent power.

[0065] The second circulation path 32 is disposed between the object to be cooled 30 and the cold storage tank 10. For example, a pump (not shown) is disposed in the second circulation path 32. During the cold-discharge operation of the cold storage system 1a, the pump operates to circulate the refrigerant 11 between the object to be cooled 30 and the cold storage tank 10 through the second circulation path 32, as indicated by the dashed arrows in FIG. 2 . Through heat exchange between the refrigerant 11 heated in the object to be cooled 30 and the cold storage module 12, the cold stored as latent heat in the cold storage material inside the cold storage module 12 is released to the refrigerant 11, thereby discharging the cold. The cold-discharge operation of the cold storage system 1a can be performed, for example, during the daytime, when temperatures tend to be high. The object to be cooled 30 is disposed, for example, at a production site in a food factory or indoors in a building. In the cold storage system 1a, not only the sensible heat of the refrigerant 11 but also the latent heat of the cold storage material can be utilized, which facilitates the storage of a large amount of cold in the cold storage tank 10.

[0066] The number of cold storage modules 12 arranged inside the cold storage tank 10 is not limited to a specific value. The shape of the cold storage module 12 is not limited to a rectangular parallelepiped and may be other shapes. The size of the cold storage module 12 is not limited to a specific size. In the cold storage system 1a, the dimensions and shape of the case 14 are not limited to a specific embodiment. In the cold storage system 1a, the case 14 may be omitted, and multiple cold storage modules 12 may be directly arranged inside the cold storage tank 10. In order to increase the amount of cold energy that can be stored in the cold storage tank 10, it is advantageous for the volume of the cold storage material present inside the cold storage tank 10 to be large. The volume of the cold storage material present inside the cold storage tank 10 can be determined taking into account the balance between the amount of cold energy and manufacturing costs.

[0067] For example, when the cold storage tank 10 is installed in a food factory or the basement of a building, rapid heat exchange between the refrigerant and the cold storage material is important from the viewpoint of rapid cold storage at night and rapid cold release during the day. Therefore, a large surface area for the cold storage module 12 is advantageous. For example, the cold storage module 12 is desirably configured to be thin, with small dimensions in a specific direction, and have a large surface area. Therefore, it is advantageous for the cold storage material contained inside the container of the cold storage module 12 to have a small thickness in its solid state. In addition, it is advantageous for the plate material forming the container of the cold storage module 12 to have a small thickness.

[0068] (Additional Notes) The above disclosure discloses the following technologies. (Technology 1) A cold storage material comprising: at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts; water; a porous substance; a silver compound; and an alcohol, wherein the salt contains an anionic atomic group having two or more oxygen atoms, and the alcohol includes at least one selected from the group consisting of monohydric alcohols having 3 to 5 carbon atoms and dihydric alcohols having 3 to 6 carbon atoms, and the molar ratio of the alcohol content to the salt content is 0.1 to 0.9%. (Technology 2) The cold storage material according to Technology 1, wherein the alcohol includes at least one selected from the group consisting of 1-propanol, iso-propanol, 1,3-propanediol, 1-butanol, 2-butanol, 1,4-butanediol, 1-pentanol, and 1,6-hexanediol. (Technology 3) The cold accumulator material according to Technology 1 or 2, wherein the porous substance includes activated carbon. (Technology 4) The cold accumulator material according to Technology 3, wherein the activated carbon has a basic surface. (Technology 5) The cold accumulator material according to Technology 3 or 4, wherein the activated carbon has at least one element selected from the group consisting of Na and K eluted into the water. (Technology 6) The cold accumulator material according to any one of Technology 1 to 5, wherein 3 mg / L or more of Na is dissolved. (Technology 7) The cold accumulator material according to any one of Technology 1 to 6, wherein 20 mg / L or more of K is dissolved. (Technology 8) The cold accumulator material according to any one of Technology 1 to 7, wherein the atomic group is a carboxylic acid having 6 or less carbon atoms. (Technology 9) The cold accumulator material according to Technology 8, wherein the atomic group is 2-ethylbutanoate. (Technology 10) The cold storage material according to any one of Techniques 1 to 9, wherein the silver compound includes at least one selected from the group consisting of Ag2O, AgO, Ag2CO3, Ag3PO4, AgF, Ag2SO4, Ag2CrO4, Ag2WO4, and a silver carboxylate having 5 or less carbon atoms.

[0069] The present disclosure will be described in more detail with reference to the following examples, but the present disclosure is not limited to the following examples.

[0070] In this example, tetra-n-butylammonium iodide was purchased from Tokyo Chemical Industry Co., Ltd. Silver nitrate was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Tetra-n-butylammonium 2-ethylbutanoate is abbreviated as "TBA-2-EB." TBA-2-EB was synthesized from the reaction of silver 2-ethylbutyrate with tetra-n-butylammonium iodide. Silver 2-ethylbutyrate was synthesized from the reaction of 2-ethylbutyric acid with silver nitrate. Tetra-n-butylammonium iodide and 2-ethylbutyric acid were purchased from Tokyo Chemical Industry Co., Ltd. Activated carbon A, an activated carbon with a basic surface, was Kuraray Co., Ltd.'s ... AgF was purchased from Sigma-Aldrich Japan LLC. Ag2CO3 was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Silver acetate was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Ag3PO4 was purchased from Sigma-Aldrich Japan LLC. Ag2CrO4 was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Ag2WO4 was purchased from Fujifilm Wako Pure Chemical Industries, Ltd.

[0071] (Example 1) As shown in Table 1, TBA-2-EB, pure water, AgO, activated carbon A, and 1-propanol were added to a screw tube having a capacity of 9 milliliters to obtain a mixture. The mixture was thoroughly stirred inside the screw tube to obtain the cold accumulator material of Example 1. The screw tube was a glass tube with a screw cap. When this cold accumulator material was in a liquid state, activated carbon A sank to the bottom of the glass tube. Activated carbon A contained particles with a maximum diameter of 1 mm or more.

[0072] (Examples 2 to 4) Cold accumulators according to Examples 2, 3, and 4 were obtained in the same manner as in Example 1, except that 1-butanol was added in place of 1-propanol in the amounts shown in Table 1. When these cold accumulators were in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0073] (Example 5) A cold accumulator according to Example 5 was obtained in the same manner as in Example 1, except that 1-pentanol was added in place of 1-propanol in the amount shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0074] (Example 6) A cold accumulator according to Example 6 was obtained in the same manner as in Example 1, except that iso-propanol was added in place of 1-propanol in the amount shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0075] (Example 7) A cold storage material according to Example 7 was obtained in the same manner as in Example 1, except that 2-butanol was added in place of 1-propanol in the amount shown in Table 1. When these cold storage materials were in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0076] (Examples 8 and 9) Cold storage materials according to Examples 8 and 9 were obtained in the same manner as in Example 1, except that 1,3-propanediol was added in place of 1-propanol in the amounts shown in Table 1. When these cold storage materials were in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0077] (Examples 10 and 11) Cold storage materials according to Examples 10 and 11 were obtained in the same manner as in Example 1, except that 1,4-butanediol was added in place of 1-propanol in the amounts shown in Table 1. When these cold storage materials were in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0078] (Example 12) A cold accumulator according to Example 12 was obtained in the same manner as in Example 1, except that 1,6-hexanediol was added in place of 1-propanol in the amount shown in Table 1. When these cold accumulators were in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0079] A cold accumulator according to Example 13 was obtained in the same manner as in Example 1, except that AgO was used instead of AgO and 1-butanol was used instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0080] (Example 14) A cold accumulator according to Example 14 was obtained in the same manner as in Example 1, except that AgO was used instead of AgO and 1,3-propanediol was used instead of 1-propanol, in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0081] A cold accumulator according to Example 15 was obtained in the same manner as in Example 1, except that AgO was used instead of AgO and 1,4-butanediol was used instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0082] (Example 16) A cold accumulator according to Example 16 was obtained in the same manner as in Example 1, except that Ag2CO3 was added instead of Ag2O and 1-butanol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0083] (Example 17) A cold accumulator according to Example 17 was obtained in the same manner as in Example 1, except that Ag2CO3 was added instead of Ag2O and 1,3-propanediol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0084] (Example 18) A cold accumulator according to Example 18 was obtained in the same manner as in Example 1, except that Ag2CO3 was added instead of Ag2O and 1,4-butanediol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0085] (Example 19) A cold accumulator according to Example 19 was obtained in the same manner as in Example 1, except that Ag acetate was added instead of AgO and 1-butanol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0086] (Example 20) A cold accumulator according to Example 20 was obtained in the same manner as in Example 1, except that Ag acetate was added instead of AgO and 1,3-propanediol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0087] (Example 21) A cold accumulator according to Example 21 was obtained in the same manner as in Example 1, except that Ag acetate was added instead of AgO and 1,4-butanediol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0088] A cold accumulator according to Example 22 was obtained in the same manner as in Example 1, except that AgPO was used instead of AgO and 1,4-butanediol was used instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0089] (Example 23) A cold accumulator according to Example 23 was obtained in the same manner as in Example 1, except that AgSO was used instead of AgO and 1,4-butanediol was used instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0090] (Example 24) A cold accumulator according to Example 24 was obtained in the same manner as in Example 1, except that AgF was added instead of AgO and 1,4-butanediol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0091] (Example 25) A cold accumulator according to Example 25 was obtained in the same manner as in Example 1, except that Ag2CrO4 was added instead of Ag2O and 1,4-butanediol was added instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0092] (Example 26) A cold accumulator according to Example 26 was obtained in the same manner as in Example 1, except that AgWO was used instead of AgO and 1,4-butanediol was used instead of 1-propanol in the amounts shown in Table 1. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0093] (Comparative Example 1) A cold accumulator according to Comparative Example 1 was obtained in the same manner as in Example 1, except that TBA-2-EB, pure water, Ag2O, and activated carbon A were added in the amounts shown in Table 2. No alcohol was added to the cold accumulator according to Comparative Example 1.

[0094] (Comparative Example 2) A cold storage material according to Comparative Example 2 was obtained in the same manner as in Example 1, except that TBA-2-EB, pure water, AgO, and 1,4-butanediol were added in the amounts shown in Table 2. Activated carbon A was not added to the cold storage material according to Comparative Example 2.

[0095] (Comparative Example 3) A cold accumulator according to Comparative Example 3 was obtained in the same manner as in Example 1, except that TBA-2-EB, pure water, activated carbon A, and 1,4-butanediol were added in the amounts shown in Table 2. AgO was not added to the cold accumulator according to Comparative Example 3.

[0096] (Comparative Example 4) A cold accumulator according to Comparative Example 4 was obtained in the same manner as in Example 1, except that ethanol was added in place of 1-propanol in the amount shown in Table 2. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0097] (Comparative Example 5) A cold accumulator according to Comparative Example 5 was obtained in the same manner as in Example 1, except that 1-heptanol was added instead of 1-propanol in the amount shown in Table 2. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0098] (Comparative Example 6) A cold accumulator according to Comparative Example 6 was obtained in the same manner as in Example 1, except that 1-octanol was added in place of 1-propanol in the amount shown in Table 2. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0099] (Comparative Example 7) A cold accumulator according to Comparative Example 7 was obtained in the same manner as in Example 1, except that 1,2-ethanediol was added in place of 1-propanol in the amount shown in Table 2. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0100] (Comparative Example 8) A cold accumulator according to Comparative Example 8 was obtained in the same manner as in Example 1, except that 1,7-heptanediol was added in place of 1-propanol in the amount shown in Table 2. When this cold accumulator was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0101] (Measurement of Melting Point and Latent Heat) Using a PerkinElmer Japan DSC-8500 differential scanning calorimeter, differential scanning calorimetry (DSC) was performed on approximately 10 milligrams of each sample obtained from the regenerator material according to each Example and Comparative Example. This measurement was performed by adjusting the temperature as preprogrammed. First, the temperature of the reference material was maintained at 30°C for 10 minutes. Next, the temperature of the reference material was reduced at a rate of 1°C / minute. During this cooling process, a temperature increase associated with the crystallization of the regenerator material was observed as an exothermic peak, and then the temperature of the regenerator material converged to the programmed temperature. This confirmed that the crystallization of the regenerator material was complete. After the temperature of the reference material reached minus 20°C, the temperature of the reference material was maintained at minus 20°C for 10 minutes. Then, the temperature of the reference material was increased from minus 20°C to 30°C at a rate of 1°C / minute. When the crystallized regenerator material began to melt, the temperature increase stagnated because heat was absorbed by the amount of latent heat. When the melting was completed, the temperature increase line converged to the original program line. The temperature of the endothermic peak at this time was determined to be the melting point of the regenerator material, and the amount of heat absorbed was determined to be the latent heat of the regenerator material. In this way, the melting point and latent heat of the regenerator material according to each example and each comparative example were measured using the DSC-8500. The results are shown in Table 3.

[0102] (Performance Evaluation) The cold storage materials according to each Example and Comparative Example were first heated at 20°C for 1 hour. Next, they were cooled at a temperature 5°C lower than the melting point for 10 hours. Subsequently, they were heated at a temperature 1°C higher than the melting point for 14 hours, followed by cooling at a temperature 5°C lower than the melting point for 10 hours. This 24-hour cycle was repeated 10 times. In the first hour of the 10-hour cooling period at a temperature 5°C lower than the melting point in the 24-hour cycle, if the transparent liquid phase in the cold storage material completely disappeared and the entire cold storage material turned white or crystallized, the crystallization characteristic was evaluated as "A" when this case was visually observed 7 or more times during the 10 cycles, and the entire cold storage material was completely crystallized by the 10th hour. If this case was visually observed less than 7 times during the 10 cycles, and the entire cold storage material was completely crystallized by the 10th hour, the crystallization characteristic was evaluated as "B." Furthermore, in a 24-hour cycle, if the entire regenerator material did not crystallize during 10 hours at a temperature 5° C. lower than the melting point, the crystallization characteristics were evaluated as “C.”

[0103] (Elution test) Activated carbon A was dispersed in pure water at 20°C at a concentration of 40 g / L to obtain a dispersion. This dispersion was filtered through a syringe filter with a pore size of 0.45 μm to obtain a liquid sample. A small amount of nitric acid was added to this liquid sample, and the sample was further diluted 100 times with pure water to obtain analytical sample α.

[0104] An aqueous solution of ammonium carboxylate was obtained in the same manner as in Example 4, except that activated carbon A and a silver compound were not added. This aqueous solution was filtered through a syringe filter with a pore size of 0.45 μm to obtain a liquid sample. A small amount of nitric acid was added to this liquid sample, which was then further diluted 100 times with pure water to obtain analytical sample β.

[0105] An aqueous solution of ammonium carboxylate salt containing activated carbon A was obtained in the same manner as in Example 4, except that no silver compound was added. This aqueous solution was filtered through a syringe filter with a pore size of 0.45 μm to obtain a liquid sample. A small amount of nitric acid was added to this liquid sample, which was then further diluted 100 times with pure water to obtain analytical sample γ.

[0106] Using an Agilent Technologies Inductively Coupled Plasma Mass Spectrometer (ICP-MS) Agilent 7700, ICP-MS was performed on the analytical samples α, β, and γ, and semi-quantitative analysis of 69 elements from Li to U was performed. As a result, in analytical sample α, Na was detected at a concentration of 5 mg / L and K was detected at a concentration of 30 mg / L. In analytical sample β, the detected concentration of Na was less than 1 mg / L, and Na was essentially not detected. In analytical sample γ, Na was detected at a concentration of 6 mg / L and K was detected at a concentration of 40 mg / L. These results suggest that activated carbon A elutes Na and K into the water in the regenerator material.

[0107] It was shown that the regenerator materials according to each Example can rapidly store cold at a small degree of supercooling and can store a large amount of latent heat as cold energy in a specified cold energy storage time. On the other hand, it was shown that the regenerator materials according to each Comparative Example cannot be expected to rapidly store cold at a small degree of supercooling and are unlikely to store a large amount of latent heat as cold energy in a specified cold energy storage time.

[0108] As described above, the cold storage materials according to the examples can store cold more quickly with a smaller degree of supercooling than the cold storage materials according to the comparative examples, and can store a larger amount of latent heat as cold in a predetermined cold storage time. Therefore, the cold storage materials according to the examples are advantageous in that they can store cold with less power consumption and can keep cold for a long period of time by storing cold in a limited time.

[0109]

[0110]

[0111]

[0112] The cold storage material of the present disclosure can be used in applications where cooling or cold retention is required, such as food factories and buildings.

Claims

1. A heat storage material comprising: at least one salt selected from the group consisting of tetra-n-butylammonium carboxylates and tetra-n-butylphosphonium carboxylates; water; a porous substance; a silver compound; and an alcohol, wherein the salt contains an anionic atomic group having two or more oxygen atoms; the alcohol includes at least one selected from the group consisting of monohydric alcohols having 3 to 5 carbon atoms and dihydric alcohols having 3 to 6 carbon atoms; and the molar ratio of the alcohol content to the salt content is 0.1 to 0.9%.

2. The cold storage material according to claim 1, wherein the alcohol includes at least one selected from the group consisting of 1-propanol, iso-propanol, 1,3-propanediol, 1-butanol, 2-butanol, 1,4-butanediol, 1-pentanol, and 1,6-hexanediol.

3. The regenerator material according to claim 1, wherein the porous material includes activated carbon.

4. The regenerator material according to claim 3, wherein the activated carbon has a basic surface.

5. The regenerator material according to claim 3, wherein the activated carbon has at least one element selected from the group consisting of Na and K dissolved in the water.

6. The cold storage material according to claim 1, wherein 3 mg / L or more of Na is dissolved therein.

7. The cold storage material according to claim 1, wherein 20 mg / L or more of K is dissolved therein.

8. The regenerator material according to claim 1, wherein the atomic group is a carboxylic acid having 6 or less carbon atoms.

9. The regenerator material according to claim 1, wherein the atomic group is 2-ethylbutanoate.

10. The cold storage material according to claim 1, wherein the silver compound includes at least one selected from the group consisting of Ag2O, AgO, Ag2CO3, Ag3PO4, AgF, Ag2SO4, Ag2CrO4, Ag2WO4, and a silver carboxylate having 5 or less carbon atoms.

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