Cold storage material

Abstract

A cold storage material according to the present disclosure comprises: at least one salt that 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; activated carbon; and a silver compound. The salt contains an anionic atomic group that has two or more oxygen atoms. The activated carbon has a basic surface.

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 contains a predetermined salt and is advantageous in terms of energy saving and prolonging the cooling time.

[0006] The cold storage material according to 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; activated carbon; and a silver compound, wherein the salt contains an anionic atomic group having two or more oxygen atoms; and the surface of the activated carbon is basic.

[0007] According to the cold storage material of the present disclosure, OH is formed on the surface of the activated carbon in the cold storage material. -It is believed that ions are attracted and easily adsorbed. In addition, it is believed that the catalytic action of the silver compound easily produces tetra-n-butylammonium hydroxide semiclathrate hydrate or tetra-n-butylphosphonium hydroxide semiclathrate hydrate. Therefore, crystals of the semiclathrate hydrate of the above salt, which have a crystal structure similar to that of these semiclathrate hydrates, are easily produced even at a small degree of supercooling. The melting points of tetra-n-butylammonium hydroxide semiclathrate hydrate and tetra-n-butylphosphonium hydroxide semiclathrate hydrate are higher than the melting points of the semiclathrate hydrate of the above salt. The activated carbon and silver compound easily efficiently form semiclathrate hydrates with high melting points, even in small amounts. Therefore, most of the semiclathrate hydrate of the above salt, which has a low melting point, is easily decomposed at a temperature slightly above the melting point of the semiclathrate hydrate of the above salt. As a result, the above cold storage material can store cold with a small degree of supercooling and can store a large amount of latent heat as cold. Therefore, the above-mentioned regenerator material is advantageous from the viewpoint of energy saving and prolonging the cooling time.

[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 Forms the Basis of the Present Disclosure) At the time the present inventors arrived at the present disclosure, various attempts had been made to develop technology for eliminating supercooling in a cold storage material. It is conceivable to provide a cold storage material containing at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts. A semiclathrate hydrate of this salt has a low melting point, for example, of 20°C or less. It is conceivable to use a semiclathrate hydrate having a low melting point of 20°C or less and a semiclathrate hydrate having a high melting point of 25°C or more and having a crystalline structure similar to that of the semiclathrate hydrate having a low melting point. In this case, for example, when cooled to 5°C, the degree of supercooling of the semiclathrate hydrate having a high melting point increases to 20K or more, and crystals of the semiclathrate hydrate having a high melting point are likely to be formed. This makes it easy to eliminate supercooling of the semiclathrate hydrate having a low melting point and a crystalline structure similar to that of the semiclathrate hydrate having a high melting point. Therefore, semiclathrate hydrates with low melting points can be produced at small degrees of supercooling.

[0010] On the other hand, semiclathrate hydrates having a high melting point and mixed semiclathrate hydrates of semiclathrate hydrates having a high melting point and semiclathrate hydrates having a low melting point can be simultaneously formed. These semiclathrate hydrates cannot decompose at temperatures slightly above the melting point of the low-melting-point semiclathrate hydrate. A new problem has been discovered: when the amount of these semiclathrate hydrates is large, the amount of latent heat available in the cold storage material decreases. For this reason, the industry has assumed that it would be difficult to apply cold storage materials that form semiclathrate hydrates to applications with narrow operating temperature ranges, such as food production or food processing processes and air conditioning for cooling. The operating temperature range in such applications is, for example, a temperature range assuming cold storage at about 5°C and cold release at about 11°C.

[0011] Under these circumstances, the present inventors have searched for an additive that can produce semiclathrate hydrate crystals at a desired cooling temperature and decompose most of the semiclathrate hydrate at a desired cooling temperature. The desired cooling temperature is, for example, a temperature that is at least 5°C lower than the melting point of the semiclathrate hydrate. The desired cooling temperature is at least 1°C higher than the melting point. The present inventors conducted a great deal of trial and error in their search for such an additive. As a result, the present inventors discovered that a combination of a specific activated carbon and a silver compound makes it possible to produce semiclathrate hydrate crystals at a desired cooling temperature and to decompose most of the semiclathrate hydrate at a desired cooling temperature. Based on this new discovery, the present inventors have arrived at the subject matter of the present disclosure.

[0012] Therefore, the present disclosure provides a cold storage material that is advantageous from the standpoints of energy saving and extending the cooling time, while containing at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts.

[0013] 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.

[0014] (First Embodiment) Hereinafter, a first embodiment will be described with reference to FIG.

[0015] [1-1. Configuration] The cold storage material in the first embodiment includes at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts, water, activated carbon, and a silver compound. The salt contains an anionic atomic group having two or more oxygen atoms. The surface of the activated carbon is basic.

[0016] Semiclathrate hydrate is formed during the crystallization of 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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).

[0022] The regenerator material can be cooled and reused.

[0023] 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 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.

[0024] Regarding condition (I), for example, in a food production or food 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 less than 5°C, there is a possibility that the refrigerant will freeze due to variations in the operating conditions of the refrigerator. It is desirable that condition (I) be satisfied in order to prevent the refrigerant from freezing.

[0025] Regarding condition (II), in food production and processing processes and 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.

[0026] 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.

[0027] In the art, the heat of fusion is also called the latent heat.

[0028] In the salt of the cold accumulator 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 at least one selected from the group consisting of 2-ethylbutanoate, acetate, and pentanoate. In this case, the cold accumulator material is more likely to satisfy the above conditions (I) and (II). In the salt of the cold accumulator material, the anionic atomic group is SO4 2- or CO 2- or PO4 3- or NO3 - may be.

[0029] 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.

[0030] The activated carbon is not limited to a specific type as long as its surface is basic. For example, when activated carbon removed from a regenerator material is washed and dispersed in pure water, if the pH of the dispersion is basic, the surface of the activated carbon can be determined to be basic. The activated carbon may, for example, have at least one element selected from the group consisting of Na and K eluted into the water of the regenerator material. For example, the activated carbon may be one that, when dispersed in pure water, elutes at least one element selected from the group consisting of Na and K into the pure water.

[0031] The concentration of Na dissolved in the water of the cold storage material is not limited to a specific value. The concentration is, for example, 3 mg / L or more. At least a part of the Na dissolved in the water of the cold storage material comes from activated carbon.

[0032] The concentration of potassium dissolved in the water 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 water in the cold storage material comes from activated carbon.

[0033] The content of activated carbon 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.

[0034] In the regenerator material, the size of the activated carbon is not limited to a specific value. The activated carbon may contain particles having a maximum diameter of, for example, 1 mm or more. The activated carbon may also contain particles having a maximum diameter of less than 1 mm.

[0035] The activated carbon may be, for example, sunk in the liquid regenerator material, or part of the activated carbon may be floating in the liquid regenerator material.

[0036] 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.

[0037] 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.

[0038] The cold storage material may further contain additives other than the above-mentioned salt, water, activated carbon, and silver compound. Examples of the additives include a supercooling inhibitor, a thickener, and a preservative.

[0039] The cold accumulator may not contain any additives, that is, the cold accumulator may be composed only of the above salt, water, activated carbon, and silver compound.

[0040] The regenerator material can be produced by mixing the above salt, water, activated carbon, and a silver compound.

[0041] [1-2. Operation] The operation and function of the regenerator material in the first embodiment will be described.

[0042] When using a cold storage material, cold storage and release are repeated. As mentioned above, the surface of activated carbon is basic. Therefore, during cold storage, OH groups are formed on the surface of the activated carbon of the cold storage material. - Ions can be attracted and adsorbed. In addition, tetra-n-butylammonium hydroxide semiclathrate hydrate or tetra-n-butylphosphonium hydroxide semiclathrate hydrate can be produced by the catalytic action of the silver compound. This allows crystals of semiclathrate hydrates of the above salts, which have a similar crystal structure to those of the semiclathrate hydrates, to be produced at a small degree of supercooling during cold storage.

[0043] Upon cooling, the semiclathrate hydrate of the salt decomposes. The activated carbon and silver compound can efficiently form a small amount of tetra-n-butylammonium hydroxide semiclathrate hydrate or tetra-n-butylphosphonium hydroxide semiclathrate hydrate. Therefore, upon cooling, most of the semiclathrate hydrate of the salt, which has a low melting point, tends to decompose at a temperature slightly above its melting point. 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.

[0044] [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, activated carbon, and a silver compound. The salt contains an anionic atomic group having two or more oxygen atoms. The surface of the activated carbon is basic.

[0045] As a result, when storing cold in the cold storage material, crystals of the semiclathrate hydrate of the salt are likely to be generated with a small degree of supercooling. For example, crystals of the semiclathrate hydrate of the salt are likely to be generated at temperatures 5°C lower than the melting point of the cold storage material. This makes it easy to reduce the energy required to store cold in the cold storage material. In addition, when cooling, most of the semiclathrate hydrate of the salt having a low melting point is likely to decompose at temperatures slightly higher than the melting point. This makes it easy to extend the time during which cold storage is possible. In this way, the cold storage material is advantageous from the perspectives of energy saving and extending the cooling time.

[0046] As in the present embodiment, the activated carbon may have at least one element selected from the group consisting of Na and K dissolved in 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.

[0047] As in the present embodiment, 3 mg / L or more of Na may be dissolved in the water of the cold storage material, in which case crystals of the semiclathrate hydrate of the salt are more likely to be formed at a small degree of supercooling.

[0048] As in the present embodiment, 20 mg / L or more of K may be dissolved in the water of the regenerator material. In this case, crystals of the semiclathrate hydrate of the above salt are more likely to be formed at a small degree of supercooling.

[0049] As in the present embodiment, the anionic atomic group may be a carboxylic acid (carboxylate ion) having six or less carbon atoms. In this case, crystals of the semiclathrate hydrate of the salt are more likely to be formed at a small degree of supercooling.

[0050] 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, crystals of the semiclathrate hydrates of the above salts 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 in the cold storage material is likely to be large. Therefore, the cold storage material is more advantageous from the perspectives of energy conservation and prolonged cooling time.

[0051] 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 a small degree of supercooling. Therefore, the regenerator material is more advantageous from the viewpoints of energy conservation and prolonged cooling time.

[0052] Second Embodiment Hereinafter, a second embodiment will be described with reference to FIG.

[0053] FIG. 2 shows a cold energy storage system 1a according to the second embodiment.

[0054] 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.

[0055] 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.

[0056] The first circulation path 22 is formed between the refrigerator 20 and the cold storage tank 10. For example, a pump (not shown) is arranged in the first circulation path 22. During the cold storage operation of the cold storage system 1a, the 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 the latent heat is stored as cold energy. During the cold storage operation of the cold storage system 1a, the refrigerator 20 is operated, for example, using overnight power.

[0057] The second circulation path 32 is formed 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 storage system 1a's cold discharge operation, 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, cold stored as latent heat in the cold storage material inside the cold storage module 12 is released to the refrigerant 11, thereby discharging cold. The cold storage system 1a's cold discharge operation 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In this example, tetra-n-butylammonium acetate is abbreviated as "TBA-Acetate." TBA-Acetate was purchased from Sigma-Aldrich Japan, LLC. Tetra-n-butylammonium pentanoate is abbreviated as "TBA-Pentanoate." TBA-Pentanoate was synthesized from the reaction of silver pentanoate with tetra-n-butylammonium iodide. Silver pentanoate was synthesized from the reaction of pentanoic acid with silver nitrate. Tetra-n-butylammonium iodide and pentanoic acid were purchased from Tokyo Chemical Industry Co., Ltd. Silver nitrate was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Tetra-n-butylphosphonium acetate is abbreviated as "TBP-Acetate." TBP-Acetate was synthesized from the reaction of silver acetate with tetra-n-butylphosphonium iodide. Silver acetate and tetra-n-butylphosphonium iodide were purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Tetra-n-butylammonium 2-ethylbutanoate is abbreviated as "TBA-2-EB." TBA-2-EB was synthesized by reacting silver 2-ethylbutyrate with tetra-n-butylammonium iodide. Silver 2-ethylbutyrate was synthesized by reacting 2-ethylbutyric acid with silver nitrate. Tetra-n-butylammonium iodide and 2-ethylbutyric acid were purchased from Tokyo Chemical Industry Co., Ltd. Silver nitrate was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Activated carbon A, whose surface exhibits basicity, was Kuraray Co., Ltd., Kuraray Co., Ltd., a product for removing toxic or malodorous gases. Activated carbon B, whose surface exhibits acidity, was BGX, purchased from Kuraray Co., Ltd. AgO was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. AgO was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. Ag acetate was purchased from Fujifilm Wako Pure Chemical Industries, Ltd. AgF was purchased from Sigma-Aldrich Japan, LLC. AgCO was purchased from Fujifilm Wako Pure Chemical Industries, Ltd.

[0062] (Example 1) As shown in Table 1, TBA-Acetate, pure water, AgO, and activated carbon A 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 of Example 1. The screw tube was a glass tube with a screw cap. When the cold accumulator of Example 1 was in a liquid state, the activated carbon A sank to the bottom of the glass tube. The activated carbon A contained particles with a maximum diameter of 1 mm or more.

[0063] (Example 2) A cold accumulator according to Example 2 was obtained in the same manner as in Example 1, except that TBA-Pentanoate, pure water, AgO, and activated carbon A were added in the amounts shown in Table 1. When the cold accumulator according to Example 2 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0064] (Example 3) A cold accumulator according to Example 3 was obtained in the same manner as in Example 1, except that TBP-Acetate, pure water, AgO, and activated carbon A were added in the amounts shown in Table 1. When the cold accumulator according to Example 3 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0065] (Example 4) A cold accumulator according to Example 4 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 1. When the cold accumulator according to Example 4 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0066] (Example 5) A cold accumulator according to Example 5 was obtained in the same manner as in Example 1, except that TBA-Acetate, pure water, AgO, and activated carbon A were added in the amounts shown in Table 1. When the cold accumulator according to Example 5 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0067] (Example 6) A cold accumulator according to Example 6 was obtained in the same manner as in Example 1, except that TBA-Acetate, pure water, Ag acetate, and activated carbon A were added in the amounts shown in Table 1. When the cold accumulator according to Example 6 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0068] (Example 7) A cold accumulator according to Example 7 was obtained in the same manner as in Example 1, except that TBA-2-EB, pure water, AgO, and activated carbon A were added in the amounts shown in Table 1. When the cold accumulator according to Example 7 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0069] (Example 8) A cold storage material according to Example 8 was obtained in the same manner as in Example 1, except that TBA-2-EB, pure water, AgF, and activated carbon A were added in the amounts shown in Table 1. When the cold storage material according to Example 8 was in a liquid state, the activated carbon A sank to the bottom of the glass tube.

[0070] (Example 9) A cold storage material according to Example 9 was obtained in the same manner as in Example 1, except that TBA-2-EB, pure water, AgCO, and activated carbon A were added in the amounts shown in Table 1. When the cold storage material according to Example 9 was in a liquid state, activated carbon A sank to the bottom of the glass tube.

[0071] (Comparative Example 1) A cold accumulator according to Comparative Example 1 was obtained in the same manner as in Example 1, except that TBA-Acetate, pure water, and AgO were added in the amounts shown in Table 1. The cold accumulator according to Comparative Example 1 did not contain activated carbon.

[0072] 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-Acetate, pure water, Ag2O, and activated carbon B were added in the amounts shown in Table 1.

[0073] (Comparative Example 3) A cold accumulator according to Comparative Example 3 was obtained in the same manner as in Example 1, except that TBA-Acetate, pure water, and activated carbon A were added in the amounts shown in Table 1. The cold accumulator according to Comparative Example 3 did not contain Ag2O.

[0074] (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 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 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 cold storage material began to melt, the temperature rise stagnated because heat was absorbed by the amount of latent heat. When the melting was completed, the temperature rise converged back to the original program line. The temperature of the endothermic peak at this time was determined to be the melting point of the cold storage material, and the amount of heat absorbed was determined to be the latent heat of the cold storage material. In this way, the melting point and latent heat of the cold storage material according to each example and each comparative example were measured using the DSC-8500. The results are shown in Table 2.

[0075] (Performance Evaluation) The regenerator materials according to each Example and Comparative Example were subjected to a cycle of heating at 20°C for 1 hour, cooling at a temperature 5°C lower than the melting point for 10 hours, and heating at a temperature 1°C higher than the melting point for 14 hours. After 10 hours of cooling at a temperature 5°C lower than the melting point, if the entire regenerator material was visually crystallized, the crystallization characteristic was evaluated as "A." Otherwise, the crystallization characteristic was evaluated as "X." After 14 hours of heating at a temperature 1°C higher than the melting point, the proportion of decomposed crystals in the entire crystals was determined based on the visually confirmed state of decomposition of the crystals. Based on this proportion, if it was expected that a latent heat of 165 kJ / kg or more could be released, the melting characteristic was evaluated as "A." Otherwise, the melting characteristic was evaluated as "X." The evaluation results of the crystallization and melting characteristics of the regenerator materials according to each Example and Comparative Example are shown in Table 2.

[0076] (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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The cold storage materials according to each example were expected to be able to store cold at a small degree of supercooling and to store a large amount of latent heat as cold energy. On the other hand, the cold storage materials according to each comparative example were not expected to store cold at a small degree of supercooling and were unlikely to be able to store a large amount of latent heat as cold energy.

[0081] As described above, the regenerator materials according to the examples can store cold with a smaller degree of supercooling and can store a larger amount of latent heat as cold than the regenerator materials according to the comparative examples. Therefore, the regenerator materials according to the examples are advantageous in terms of energy saving and prolonging the cooling time.

[0082]

[0083]

[0084] 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. at least one salt selected from the group consisting of tetra-n-butylammonium carboxylate salts and tetra-n-butylphosphonium carboxylate salts; Water and Activated carbon and a silver compound, The salt comprises an anionic group having two or more oxygen atoms, The surface of the activated carbon is basic. Cold storage material.

2. 2. The regenerator material according to claim 1, wherein the activated carbon has at least one element selected from the group consisting of Na and K dissolved in the water.

3. 2. The regenerator material according to claim 1, wherein the water contains 3 mg / L or more of dissolved Na.

4. 2. The regenerator material according to claim 1, wherein the water contains 20 mg / L or more of dissolved potassium.

5. 2. The regenerator material according to claim 1, wherein the atomic group is a carboxylic acid having six or fewer carbon atoms.

6. The regenerator material according to claim 5, wherein the atomic group is 2-ethylbutanoate.

7. The silver compound is Ag 2 O, AgO, Ag 2 CO 3 , Ag 3 P.O. 4 , AgF, Ag 2 SO 4 , Ag 2 CrO 4 , Ag 2 WO 4 7. The regenerator material according to claim 1, comprising at least one selected from the group consisting of: and a silver carboxylate having 5 or less carbon atoms.