JP2022188452A - Heat storage material composition, and heat storage system for cooling and heating of building - Google Patents

Abstract

To provide a heat storage material composition that has a melting point of 20-22°C with a latent heat of fusion being great in a narrow temperature range and a heat storage system for cooling and heating of a building.SOLUTION: A heat storage material composition comprises a basis comprising sodium sulfate 10-hydrate, disodium hydrogenphosphate 12-hydrate, sodium carbonate 10-hydrate, and sodium metaborate 4-hydrate with a melting point of 20-22°C and a latent heat of fusion of 190 J/g or more. A heat storage system for cooling and heating of a building is provided with a heat storage material module including the heat storage material composition.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a heat storage material composition and a heat storage system for cooling and heating buildings.

Conventionally, there has been known a latent heat storage material composition that utilizes latent heat generated or absorbed during a phase change from a liquid to a solid or from a solid to a liquid. The latent heat storage material composition is used, for example, in a heat storage system for cooling and heating buildings.

The latent heat storage material composition generally has a large heat storage capacity, a melting point within a predetermined temperature range, long-term stability, low cost, no toxicity, and no corrosiveness. characteristics such as no

A latent heat storage material composition for a heat storage system for cooling and heating a building is required to have a large latent heat of fusion, which means how much heat can be stored per unit weight. A large latent heat of fusion is preferable because sufficient heat storage can be achieved with a small amount of the latent heat storage material composition.

Patent Document 1 discloses a heat storage material composition comprising sodium sulfate and/or its eutectic salt, water, and a crosslinked polymer, and containing 13 to 27 mol of water per 1 mol of sodium sulfate.

JP-A-5-25467

However, among sodium sulfate hydrates, for example, sodium sulfate decahydrate has a phase change temperature of about 32°C. As described above, the heat storage material composition of Patent Document 1 has a problem that it is difficult to adjust the melting point within the range of 20 to 22°C. Moreover, the heat storage material composition of Patent Document 1 has a problem that the heat storage amount is small. Furthermore, in the heat storage material composition of Patent Document 1, when water is added, the latent heat generation region increases, so there is a problem that the latent heat of fusion is small within a narrow temperature region.

The present invention has been made in view of the above problems. An object of the present invention is to provide a heat storage material composition having a melting point in the range of 20 to 22° C. and a large latent heat of fusion within a narrow temperature range, and a heat storage system for cooling and heating buildings.

A heat storage material composition according to an aspect of the present invention includes a main agent comprising sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, sodium carbonate decahydrate, and sodium metaborate tetrahydrate. , a melting point in the range of 20 to 22° C., and a latent heat of fusion of 190 J/g or more.

According to the present invention, it is possible to provide a heat storage material composition having a melting point in the range of 20 to 22° C. and a large latent heat of fusion within a narrow temperature range, and a heat storage system for cooling and heating buildings.

Sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and sodium carbonate 10 in the triple composition when the content of sodium metaborate tetrahydrate in the main agent is about 2.5% by mass FIG. 3 is a ternary composition diagram of hydrate content. 2 is an enlarged view of a region A1 shown in FIG. 1; FIG. Sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and sodium carbonate decahydrate in the triple composition when the content of sodium metaborate tetrahydrate in the main agent is approximately 5% by mass It is a ternary system composition diagram of the content of the material. 4 is an enlarged view of a region A2 shown in FIG. 3; FIG.

Hereinafter, the heat storage material composition and the heat storage system according to the present embodiment will be described in detail.

[Heat storage material composition]
The heat storage material composition according to the present embodiment contains a main agent composed of sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, sodium carbonate decahydrate, and sodium metaborate tetrahydrate. A mixture of sodium sulfate decahydrate, disodium hydrogenphosphate dodecahydrate, and sodium carbonate decahydrate in the main agent is also referred to as a three-component composition.

(Main agent)
The main agent contains predetermined amounts of sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, sodium carbonate decahydrate, and sodium metaborate tetrahydrate.

<Composition in three types of composition>
In the heat storage material composition, X, Y, and Z are represented by the following formulas (1-1) to (1-6), or (2-1), depending on the content of sodium metaborate tetrahydrate in the main agent. (2-5) is preferably satisfied. Here, X, Y, and Z are the content of sodium sulfate decahydrate in 100% by mass of the three-component composition, and the content of disodium hydrogen phosphate dodecahydrate in Y% by mass. , and the content of sodium carbonate decahydrate is defined as Z% by mass. That is, X, Y, and Z are sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and sodium carbonate decahydrate in the three-component composition excluding sodium metaborate tetrahydrate from the main agent. The content (% by mass) of each substance in the hydrate is shown.

[When the content of sodium metaborate tetrahydrate is 2.0 to 3.0% by mass]
When the content of the sodium metaborate tetrahydrate in the main agent is 2.0 to 3.0% by mass, preferably 2.3 to 2.7% by mass, X, Y, and Z are represented by the following formula ( 1-1) to (1-6) are preferably satisfied.

[Number 1]
X+Y+Z=100 (1-1)
[Number 2]
X+3.9Y-162.45≧0 (1-2)
[Number 3]
X+Y-58.05≧0 (1-3)
[Number 4]
X≧18.05 (1-4)
[Number 5]
X+3.105Y-156.64≦0 (1-5)
[Number 6]
X≤26.10 (1-6)

FIG. 1 shows sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and carbonate in the three-component composition when the content of sodium metaborate tetrahydrate in the main agent is about 5% by mass. FIG. 3 is a ternary composition diagram of the content of sodium decahydrate. FIG. 2 is an enlarged view of area A1 shown in FIG. A region R1 indicated by the pentagon and its interior shown in FIG. 2 is a range that satisfies the above formulas (1-1) to (1-6).

Specifically, the straight line AB forming the pentagon represents the straight line in the case of the equality sign in Equation (1-2). A straight line BC forming the pentagon indicates a straight line in the case of equality in the equation (1-3). A straight line CD forming the pentagon indicates a straight line in the case of the equal sign in Equation (1-4). A straight line EF forming a pentagon indicates a straight line in the case of the equal sign in Equation (1-5). A straight line FA forming the pentagon indicates a straight line in the case of equality in the equation (1-6).

When the content of sodium metaborate tetrahydrate is 2.0 to 3.0% by mass, and the above X, Y, and Z satisfy the formulas (1-1) to (1-6), the heat storage material The melting point of the composition is in the range of 20 to 22° C., and the latent heat of fusion tends to be 190 J/g or more.

[When the content of sodium metaborate tetrahydrate is 4.5 to 5.5% by mass]
When the content of the sodium metaborate tetrahydrate in the main agent is 4.5 to 5.5% by mass, preferably 4.8 to 5.2% by mass, X, Y, and Z are represented by the following formula ( 2-1) to (2-5) are preferably satisfied.

[Number 7]
X+Y+Z=100 (2-1)
[Number 8]
X-2.12Y+52.02≦0 (2-2)
[Number 9]
X+0.27Y-31.48≧0 (2-3)
[Number 10]
X-1.52Y+40.11≧0 (2-4)
[Number 11]
X≤26.1 (2-5)

FIG. 3 shows sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and carbonate in the three-component composition when the content of sodium metaborate tetrahydrate in the main agent is approximately 5% by mass. FIG. 3 is a ternary composition diagram of the content of sodium decahydrate. FIG. 4 is an enlarged view of area A2 shown in FIG. The quadrangle shown in FIG. 4 and the region R2 indicated by the interior thereof are ranges that satisfy the above formulas (2-1) to (2-5).

Specifically, the straight line AB forming the quadrangle indicates the straight line in the case of the equal sign in Equation (2-2). A straight line CD forming a quadrangle indicates a straight line in the case of the equal sign in Equation (2-3). A straight line DE forming a quadrangle indicates a straight line in the case of the equal sign in Equation (2-4). A straight line FA forming a quadrangle indicates a straight line in the case of equality in the equation (2-5).

When the content of sodium metaborate tetrahydrate is 4.5 to 5.5% by mass, and the above X, Y, and Z satisfy the formulas (2-1) to (2-5), the heat storage material The melting point of the composition is in the range of 20 to 22° C., and the latent heat of fusion tends to be 190 J/g or more.

(Melting point depressant)
It is preferable that the heat storage material composition according to the present embodiment further contains a specific melting point depressant, because the melting point of the main agent is lowered. The melting point depressant includes, for example, at least one melting point selected from the group consisting of sodium chloride, potassium chloride, sodium nitrate, sodium bromide, ammonium chloride, ammonium bromide, ammonium sulfate, ammonium nitrate, ammonium phosphate, and urea. Depressants are used.

(supercooling inhibitor)
It is preferable that the heat storage material composition according to the present embodiment further contains a specific supercooling inhibitor, since supercooling of the main agent is suppressed. Examples of supercooling inhibitors include borax Na ₂ B ₄ O ₅ (OH) _{4.8H 2} O, calcium hydroxide, barium hydroxide, strontium hydroxide, aluminum hydroxide, graphite, aluminum powder, titanium dioxide, At least one supercooling inhibitor selected from the group consisting of propylene glycol, ethylene glycol, glycerin, ethylenediaminetetraacetic acid, sodium alkylsulfate, sodium alkylphosphate, potassium alkylsulfate, and potassium alkylphosphate is used.

(Phase separation inhibitor)
It is preferable that the heat storage material composition according to the present embodiment further contains a specific phase separation inhibitor, since phase separation of the main agent is suppressed. Phase separation inhibitors include, for example, sodium silicate, water glass, polyacrylic acid, sodium polyacrylate, polycarboxylate polyether polymer, sodium acrylic acid/maleic acid copolymer, and acrylic acid/sulfonic acid monomers. Sodium polymer, acrylamide/dimethylaminoethyl methacrylate dimethylsulfate copolymer, acrylamide/sodium acrylate copolymer, polyethylene glycol, polypropylene glycol, super absorbent polymer (SAP), carboxymethyl cellulose (CMC), derivatives of CMC, At least one selected from the group consisting of carrageenan, carrageenan derivatives, xanthan gum, xanthan gum derivatives, pectin, pectin derivatives, starch, starch derivatives, konjac, agar, layered silicates, and composites of the above substances A phase separation inhibitor is used.

(Characteristic)
The heat storage material composition according to the present embodiment has a melting point in the range of 20 to 22° C., and melts and solidifies in a temperature range slightly lower than the general set temperature for air conditioning of buildings. Further, the heat storage material composition according to the present embodiment has a latent heat of fusion of 190 J/g or more, and has a large latent heat of fusion within a narrow temperature range. Therefore, the heat storage material composition according to the present embodiment is suitable as a latent heat storage material composition for a heat storage system for cooling and heating buildings.

The heat storage material composition according to the present embodiment has a latent heat of fusion of 190 J/g or more, preferably 200 J/g or more, more preferably 210 J/g or more, still more preferably 220 J/g or more, and particularly preferably 230 J/g or more. be. Therefore, the heat storage material composition according to the present embodiment is suitable as a latent heat storage material composition for a heat storage system for cooling and heating buildings.

(The invention's effect)
According to the heat storage material composition according to the present embodiment, a heat storage material composition having a melting point in the range of 20 to 22° C. and a latent heat of fusion of 190 J/g or more can be obtained.

[Heat storage system for heating and cooling of buildings]
A heat storage system for cooling and heating a building according to the present embodiment includes a heat storage material module using the heat storage material composition according to the present embodiment.

(Heat storage material module)
The heat storage material module is, for example, composed of a heat storage material pack in which the heat storage material composition is filled in a container having a sufficient sealability, and a single or a plurality of the heat storage material packs are stacked, and an appropriate flow path is provided, Modularized ones are used. Examples of the container used for the heat storage material pack include an aluminum pack formed by heat-sealing an aluminum pack sheet formed by laminating a resin sheet on an aluminum sheet. The heat storage material module is installed on at least a part of the floor surface, wall surface, and ceiling surface that separate the spaces in the building.

The heat storage material modules installed in this manner store heat (cold storage) by heat exchange between the module surface and the atmosphere passing through the module surface, solar heat from sunlight, an air conditioning system using nighttime power, and the like. For example, during the daytime, the heat storage material composition in the heat storage material module is melted by the heat obtained from the space in the building, and the corresponding enthalpy is retained inside the heat storage material composition. After that, when the outside air temperature drops at night, the melted heat storage material composition solidifies and releases heat to the space in the building. When the heat storage material module is installed in the building in this way, the energy load for air conditioning can be reduced due to the action of melting and solidification of the heat storage material composition.

(The invention's effect)
According to the heat storage system according to the present embodiment, heat is stored (cold storage) by heat exchange between the module surface and the atmosphere through which the module surface is ventilated, solar heat due to solar radiation, an air conditioning system using nighttime power, and the like. can reduce the energy load for

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1] (When the content of sodium metaborate tetrahydrate is approximately 2.5% by mass)
(Production of heat storage material composition)
First, Na ₂ SO _{4.10H 2} O (manufactured by Kishida Chemical Co., Ltd., special grade), Na ₂ HPO _{4.12H 2} O (manufactured by Kishida Chemical Co., Ltd., special grade), and Na ₂ CO _{3.10H 2} O (Kishida Chemical Co., Ltd., special grade) Special grade manufactured by Kagaku Co., Ltd.) was prepared. NaBO ₂ .4H ₂ O (manufactured by Kishida Chemical Co., Ltd.) was also prepared.
_{Na2SO4.10H2O , Na2HPO4.12H2O , Na2CO3.10H2O , NaBO2.4H2O and pure _ _} A predetermined amount of water was mixed so as to make a total of about 5 g.
The amounts of Na ₂ SO _{4.10H 2} O, Na ₂ HPO _{4.12H 2} O, Na ₂ CO _{3.10H 2} O, NaBO 2.4H ₂ O and pure water depend _on the composition of the obtained heat storage material composition. was blended in an amount such that the composition shown in Table 1 was obtained. The heat storage material composition was prepared so that the content of NaBO ₂ ·4H ₂ O in the main agent was approximately 2.5% by mass.
In addition, the content of Na ₂ SO _{4.10H 2} O in 100% by mass of the three-component composition is X% by mass, the content of Na ₂ HPO _{4.12H 2} O is Y mass%, and the content of Na ₂ CO _{3.10H 2} O is The content Z mass % was as shown in Table 1.
When the obtained mixture was boiled in hot water at 50° C. or higher, a heat storage material composition was obtained (Sample No. A1).

(Measurement of melting point and latent heat of fusion)
About 20 mg of a sample was taken from the heat storage material composition, DSC (differential scanning calorimeter) was performed, and the lower limit melting temperature and the upper limit melting temperature of the heat storage material composition were measured. The lower melting limit temperature obtained was taken as the melting point.
Also, the latent heat of fusion was calculated from the peak area when the heat flow measured by a differential scanning calorimeter (DSC) was integrated over time.
The melting point and latent heat of fusion results are shown in Table 1.

[Examples 2 to 11, Comparative Examples 1 to 5] (When the content of sodium metaborate tetrahydrate is approximately 2.5% by mass)
Heat storage material compositions were obtained in the same manner as in Example 1 except that the blending amounts of each component were changed so that the obtained heat storage material composition had the composition shown in Table 1 (Sample Nos. A2 to A11 (implementation Examples 2-11), A30-A34 (Comparative Examples 1-5)). The heat storage material composition was prepared so that the content of NaBO ₂ ·4H ₂ O in the main agent was approximately 2.5% by mass.

(Measurement of melting point and latent heat of fusion)
Sample no. Melting points and latent heats of fusion of A2 to A11 and A30 to A34 were measured in the same manner as in Example 1. In addition, sample no. For A30 to A34, the melting points and latent heats of fusion could not be measured because significant precipitation occurred during sample preparation and the chemical compositions in the samples could not be specified.
Table 1 shows the results.

(Ternary composition diagram)
FIG. 1 shows sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and a ternary composition diagram of the content of sodium carbonate decahydrate. FIG. 2 is an enlarged view of area A1 shown in FIG. Sample no. Sample No. including A1. The compositions of the three compositions that constitute the main ingredients of the heat storage material compositions A1 to A11 and A30 to A34 are plotted in FIGS. 1 and 2. FIG.
In FIGS. 1 and 2, sample No. Plots of the heat storage material compositions of A1 to A11 are indicated by the symbol ◯. Moreover, sample no. Plots of the heat storage material compositions of A30 to A34 are indicated by symbols x.
In FIG. 2, a region R1 indicated by a pentagon and its interior is a region that satisfies the above formulas (1-1) to (1-6). Sample No. indicated by the symbol ○. A1 to A11 exist within region R1.

From Table 1, FIGS. 1 and 2, the sample No. within the region R1 in FIG. A1 to A11 were found to have good melting points and latent heats of fusion. Specifically, sample no. It was found that the heat storage material compositions A1 to A11 had a melting point within the range of 20 to 22° C. and a latent heat of fusion of 190 J/g or more.

On the other hand, according to Table 1, FIGS. 1 and 2, sample No. outside region R1 in FIG. It was found that at least one of melting point and latent heat of fusion was not good for A30 to A34.

[Examples 12 to 21, Comparative Examples 6 to 9] (When the content of sodium metaborate tetrahydrate is approximately 5% by mass)
Heat storage material compositions were obtained in the same manner as in Example 1, except that the blending amounts of each component were changed so that the obtained heat storage material composition had the composition shown in Table 2 (Sample Nos. A12 to A21 (implementation Examples 6 to 12), No. A22 to A25 (Comparative Examples 6 to 9)). The heat storage material composition was prepared so that the content of NaBO ₂ ·4H ₂ O in the main agent was approximately 5% by mass.

(Measurement of melting point and latent heat of fusion)
Sample no. Melting points and latent heats of fusion of A12 to A25 were measured in the same manner as in Example 1. Table 2 shows the results.

(Ternary composition diagram)
FIG. 3 shows sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, and carbonate in the three-component composition when the content of sodium metaborate tetrahydrate in the main agent is approximately 5% by mass. FIG. 3 is a ternary composition diagram of the content of sodium decahydrate. FIG. 4 is an enlarged view of area A2 shown in FIG. Sample no. The compositions of the three types of compositions constituting the main ingredients of the heat storage material compositions A12 to A21 are plotted in FIGS. 3 and 4. FIG.
3 and 4, sample No. The plots of the heat storage material compositions of A12 to A21 are indicated by symbols ◯. Moreover, sample no. Plots of the heat storage material compositions of A22 to A25 are indicated by symbols x.
In FIG. 4, the rectangle and the region R2 inside it are regions that satisfy the above formulas (2-1) to (2-5). Sample No. indicated by the symbol ○. A12 to A21 are present in region R2.

From Table 2, FIGS. 3 and 4, it can be seen that sample Nos. within region R2 in FIG. A12 to A21 were found to have good melting points and latent heats of fusion. Specifically, sample no. It was found that the heat storage material compositions A12 to A21 had a melting point in the range of 20 to 22° C. and a latent heat of fusion of 190 J/g or more.

On the other hand, from Table 2, FIG. 3 and FIG. 4, it was found that at least one of the melting point and the latent heat of fusion of the samples A22 to A25 outside the region R2 in FIG.

[Comparative Examples 10 to 13] (When the content of sodium metaborate tetrahydrate is approximately 10% by mass)
Heat storage material compositions were obtained in the same manner as in Example 1 except that the blending amounts of each component were changed so that the obtained heat storage material composition had the composition shown in Table 2 (Sample Nos. A26 to A29 (comparative Examples 10-13)). The heat storage material composition was prepared so that the content of NaBO ₂ .4H ₂ O in the main agent was approximately 10% by mass.

(Measurement of melting point and latent heat of fusion)
Sample no. Melting points and latent heats of fusion of A26 to A29 were measured in the same manner as in Example 1. Table 2 shows the results.

From Table 2, it was found that samples A26 to A29 were not good in at least one of melting point and latent heat of fusion.

Although the present invention has been described above using examples, the present invention is not limited to these examples, and various modifications are possible within the scope of the present invention.

Claims (7)

Contains a main agent consisting of sodium sulfate decahydrate, disodium hydrogen phosphate dodecahydrate, sodium carbonate decahydrate, and sodium metaborate tetrahydrate,
a melting point in the range of 20 to 22°C,
A heat storage material composition having a latent heat of fusion of 190 J/g or more. When the content of the sodium metaborate tetrahydrate in the main agent is 2.0 to 3.0% by mass,
X the content of the sodium sulfate decahydrate in 100% by mass of the three-component composition consisting of the sodium sulfate decahydrate, the disodium hydrogen phosphate dodecahydrate, and the sodium carbonate decahydrate % by mass, the content of disodium hydrogen phosphate dodecahydrate as Y mass %, and the content of sodium carbonate decahydrate as Z mass %, where X, Y, and Z are represented by the following formula: The heat storage material composition according to claim 1, which satisfies (1-1) to (1-6).
[Number 1]
X+Y+Z=100 (1-1)
[Number 2]
X+3.9Y-162.45≧0 (1-2)
[Number 3]
X+Y-58.05≧0 (1-3)
[Number 4]
X≧18.05 (1-4)
[Number 5]
X+3.105Y-156.64≦0 (1-5)
[Number 6]
X≤26.10 (1-6) When the content of the sodium metaborate tetrahydrate in the main agent is 4.5 to 5.5% by mass,
X the content of the sodium sulfate decahydrate in 100% by mass of the three-component composition consisting of the sodium sulfate decahydrate, the disodium hydrogen phosphate dodecahydrate, and the sodium carbonate decahydrate % by mass, the content of disodium hydrogen phosphate dodecahydrate as Y mass %, and the content of sodium carbonate decahydrate as Z mass %, where X, Y, and Z are represented by the following formula: The heat storage material composition according to claim 1, which satisfies (2-1) to (2-5).
[Number 7]
X+Y+Z=100 (2-1)
[Number 8]
X-2.12Y+52.02≦0 (2-2)
[Number 9]
X+0.27Y-31.48≧0 (2-3)
[Number 10]
X-1.52Y+40.11≧0 (2-4)
[Number 11]
X≤26.1 (2-5) 1. Further comprising at least one melting point depressant selected from the group consisting of sodium chloride, potassium chloride, sodium nitrate, sodium bromide, ammonium chloride, ammonium bromide, ammonium sulfate, ammonium nitrate, ammonium phosphate, and urea. 4. The heat storage material composition according to any one of items 1 to 3. Borax Na ₂ B ₄ O ₅ (OH) _{4.8H 2} O, calcium hydroxide, barium hydroxide, strontium hydroxide, aluminum hydroxide, graphite, aluminum powder, titanium dioxide, propylene glycol, ethylene glycol, glycerin, ethylenediamine 5. The method according to any one of claims 1 to 4, further comprising at least one supercooling inhibitor selected from the group consisting of tetraacetic acid, sodium alkylsulfate, sodium alkylphosphate, potassium alkylsulfate, and potassium alkylphosphate. The heat storage material composition described. Sodium silicate, water glass, polyacrylic acid, sodium polyacrylate, polycarboxylate polyether polymer, sodium acrylic/maleic acid copolymer, sodium acrylic acid/sulfonic acid monomer copolymer, acrylamide/dimethylaminoethyl methacrylate dimethyl sulfate copolymer, acrylamide/sodium acrylate copolymer, polyethylene glycol, polypropylene glycol, super absorbent polymer (SAP), carboxymethyl cellulose (CMC), CMC derivatives, carrageenan, carrageenan derivatives, xanthan gum, xanthan gum at least one phase separation inhibitor selected from the group consisting of derivatives of, pectin, pectin derivatives, starch, starch derivatives, konjac, agar, layered silicates, and composites of these substances. The heat storage material composition according to any one of Items 1 to 5. A heat storage system for cooling and heating a building, comprising a heat storage material module using the heat storage material composition according to any one of claims 1 to 6.

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