JP7137654B1 - Latent heat storage material composition - Google Patents

Abstract

A latent heat storage material composition is provided that can lower the melting point to the 20° C. level even when sodium acetate trihydrate, which is a latent heat storage material, is used as a main component.
A latent heat storage material composition (1) includes a latent heat storage material (10) containing sodium acetate trihydrate as a main component, and a melting point adjuster for adjusting the melting point of the latent heat storage material (10). In the latent heat storage material composition containing urea as the additive 20 of 1, the melting point adjuster contains a substance belonging to sugar alcohol as the first additive 20 and the second additive 30. It contains a supercooling inhibitor that promotes the induction of crystallization of the latent heat storage material 10, and the supercooling inhibitor is histidine (supercooling inhibitor 40A).
[Selection drawing] Fig. 1

Description

The present invention relates to a latent heat storage material that stores or dissipates heat by utilizing the input and output of latent heat associated with a phase change, and a latent heat storage material composition containing an additive that adjusts the physical properties of the latent heat storage material.

A latent heat storage material (PCM: Phase Change Material) has the property of storing or dissipating heat by utilizing the input and output of latent heat accompanying a phase change. By extracting the stored heat at the demand destination as needed, energy can be used effectively without waste. Latent heat storage materials are roughly classified into organic compound-based heat storage materials represented by paraffin and inorganic salt hydrate-based heat storage materials such as sodium acetate trihydrate (CH ₃ COONa.3H ₂ O). Thermal storage materials for systems are also well known.

By the way, in recent years, the industrial world has paid much attention to the development of technology for positively utilizing the thermal energy stored in the latent heat storage material. For example, when a latent heat storage material whose melting point is in the 20°C temperature range is used, in a house where energy saving measures have been taken by using the latent heat storage material in the walls and floors, etc., heat from sunlight during the daytime By storing heat in the heat storage material, it is possible to suppress an increase in room temperature. On the other hand, if the latent heat is radiated at night, it becomes possible to suppress the decrease in room temperature. Therefore, a comfortable living space with room temperature of 20° C. can be provided by the latent heat storage material.

Thus, when trying to use a latent heat storage material for housing, paraffin with a melting point in the range of 20° C. has been studied so far as the latent heat storage material. However, paraffin is flammable. Therefore, a non-combustible or flame-retardant latent heat storage material is desired. Therefore, the present applicant proposed a latent heat storage material composed mainly of sodium acetate trihydrate (CH ₃ COONa.3H ₂ O) (melting point: 58°C) as a latent heat storage material that seems to be able to meet this demand. Focused on things.

A latent heat storage material composition containing sodium acetate trihydrate as a main component is disclosed in Patent Document 1, for example. Patent Document 1 discloses a latent heat storage material composition containing sodium acetate trihydrate and a latent heat storage material such as erythritol as a main component and containing urea as a melting point adjuster. According to Patent Document 1, the addition of urea, which has the effect of generating fine crystals, prevents the latent heat storage material composition from forming large lumps or aggregates of irregularly sized lumps during solidification, and has flexibility and fluidity. It can be an aggregate of fine particles. Urea is said to be able to effectively adjust the melting point of the latent heat storage material by adding a relatively small amount.

JP 2015-218212 A

However, in Patent Document 1, regarding how low the melting point can be adjusted for a latent heat storage material composition containing sodium acetate trihydrate having a melting point of 58° C. ) and below the freezing point (30° C.). Since it is preferable to use a latent heat storage material with a melting point in the range of 20° C. for the above-described residential applications, the latent heat storage material composition of Patent Document 1 cannot be used as a heat storage material that can replace paraffin.

The present invention has been made to solve the above problems, and can lower the melting point to the 20° C. level even when sodium acetate trihydrate, which is a latent heat storage material, is used as the main component. An object of the present invention is to provide a latent heat storage material composition.

In order to achieve the above object, the latent heat storage material composition according to the present invention has the following configuration.
(1) A latent heat storage material containing sodium acetate trihydrate (CH ₃ COONa·3H ₂ O) as a main component, and a melting point adjuster for adjusting the melting point of the latent heat storage material. In the latent heat storage material composition containing urea as additive 1, the melting point adjuster contains a substance belonging to sugar alcohol as a second additive together with the first additive. It contains a supercooling inhibitor that promotes the induction of crystallization of the latent heat storage material, and the supercooling inhibitor is histidine (C ₆ H ₉ N ₃ O ₂ ) or a phosphate hydrate containing metal ions. It is characterized by being at least one of them.
(2) In the latent heat storage material composition described in (1), the phosphate hydrate is disodium hydrogen phosphate dodecahydrate (Na ₂ HPO _{4.12H 2} O). and
(3) In the latent heat storage material composition described in (1) or (2), the substance belonging to sugar alcohol is erythritol (C ₄ H ₁₀ O ₄ ).
(4) In the latent heat storage material composition described in (3), the supercooling inhibitor is histidine or disodium hydrogen phosphate dodecahydrate, and the melting point of the latent heat storage material is in the 20s. It is characterized by being adjusted.

The action and effect of the latent heat storage material composition according to the present invention having the above configuration will be described.
(1), (2) A latent heat storage material containing sodium acetate trihydrate (CH ₃ COONa·3H ₂ O) as a main component, and a melting point adjuster for adjusting the melting point of the latent heat storage material. In the latent heat storage material composition containing urea as the first additive as the agent, the melting point adjuster contains a substance belonging to sugar alcohol as the second additive together with the first additive. and a supercooling inhibitor that promotes the induction of crystallization of the latent heat storage material, and the supercooling inhibitor is histidine (C ₆ H ₉ N ₃ O ₂ ) or, for example, disodium hydrogen phosphate dodecahydrate It is characterized by being at least one of phosphate hydrates containing metal ions such as hydrates (Na ₂ HPO ₄ .12H ₂ O).

Due to this feature, even if the latent heat storage material composition according to the present invention contains sodium acetate trihydrate, which is a latent heat storage material, as a main component, the latent heat storage material composition according to the present invention can be used as a latent heat storage material. For example, the melting point can be lowered by 30°C or more from the melting point of 58°C. In addition, sodium acetate trihydrate is a latent heat storage material that is particularly prone to supercooling among latent heat storage materials made of inorganic salt hydrates. can be effectively suppressed by the supercooling inhibitor.

Therefore, according to the latent heat storage material composition of the present invention, it is possible to lower the melting point of the latent heat storage material containing sodium acetate trihydrate as a main component to the 20° C. level, which is an excellent effect.

In the latent heat storage material composition described in (3), the substance belonging to sugar alcohol is erythritol (C ₄ H ₁₀ O ₄ ).

Due to this feature, the melting point of the latent heat storage material composition according to the present invention is, for example, about 30° C. lower than the 58° C. melting point of sodium acetate trihydrate, which is the main component. It becomes a melting point adjuster suitable for melting point depression.

In the latent heat storage material composition described in (4), the supercooling inhibitor is histidine or disodium hydrogen phosphate dodecahydrate, and the melting point of the latent heat storage material is adjusted to the 20s. characterized by

Due to this feature, when the latent heat storage material composition according to the present invention is disposed, for example, on a wall, floor, or the like for a house in which energy saving measures are taken, the latent heat storage material composition according to the present invention can be used during the daytime. By accumulating the heat from sunlight, it becomes possible to suppress the increase in room temperature. On the other hand, by dissipating the latent heat stored in the latent heat storage material composition according to the present invention at night, it is possible to suppress the decrease in room temperature. Therefore, the latent heat storage material composition according to the present invention can contribute to providing a comfortable living space with room temperature in the range of 20°C.

FIG. 2 is a diagram schematically showing constituent components of latent heat storage material compositions according to Examples 1 and 2 of the embodiment; 2 is a table summarizing the contents of constituent components of latent heat storage material compositions and measurement results of melting points and heat storage amounts by DSC for Examples 1 and 2 and Comparative Examples 1 and 2 thereof. 2 is a graph showing the results of Verification Test 1, collectively showing changes in the state of latent heat storage material compositions according to Examples 1 and 2 and Comparative Examples 1 and 2 thereof. 4 is a graph showing the melting point peak and heat storage amount of the latent heat storage material composition according to Example 1, and is a graph showing experimental results when histidine is used as a supercooling inhibitor. 2 is a graph showing the melting point peak and heat storage amount of the latent heat storage material composition according to Example 2, and is a graph showing experimental results when disodium hydrogen phosphate dodecahydrate is used as a supercooling inhibitor. is. 4 is a graph showing the melting point peak and heat storage amount of the latent heat storage material according to Comparative Example 1, and is a graph showing experimental results when neither a melting point adjuster nor a supercooling inhibitor is added. 4 is a table showing the results of an investigation test in which the phase state of a latent heat storage material composition using an amino acid as a supercooling inhibitor was visually confirmed for each substance that constitutes the supercooling inhibitor.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment is described in detail based on drawing about the latent heat storage material composition which concerns on this invention.

As exemplified above, the latent heat storage material composition according to the present invention is installed inside a building, such as inside a wall or under a floor, as an energy-saving measure for a house. It is used for the purpose of actively utilizing the thermal energy from the latent heat stored in the latent heat storage material, such as adjusting the indoor temperature to a comfortable temperature by dissipating the latent heat into the room at night. The latent heat storage material composition according to the present invention is subdivided into bags or capsule-like containers (not shown), and the containers are filled in a liquid-tight and air-tight manner without leakage. The latent heat storage material composition can take out the stored heat as needed by utilizing the input and output of latent heat accompanying the phase change between the liquid phase and the solid phase, and repeats the cycle of heat storage and heat release multiple times. .

First, the latent heat storage material composition 1 will be described. FIG. 1 is a diagram schematically showing constituent components of latent heat storage material compositions according to Examples 1 and 2 of the embodiment. As shown in FIG. 1, the latent heat storage material composition 1 according to the present embodiment contains sodium acetate trihydrate (CH ₃ COONa·3H ₂ O) as a main component as a latent heat storage material 10 that stores or releases heat. , two kinds of melting point adjusters (first additive 20 and second additive 30) for adjusting the melting point, and supercooling prevention agent 40 are blended. The supercooling inhibitor 40 is an additive that promotes the induction of crystallization of the latent heat storage material 10 .

Sodium acetate trihydrate alone has a hydration number of 3, a molecular weight [g/mol] of 136.08, a melting point of 58°C, a heat storage of about 276 kJ/kg (400 kJ/L), and is readily soluble in water at temperatures below the melting point. Although it is in a solid state, it is very susceptible to supercooling.

The first additive 20 (first melting point modifier) is urea (CH ₄ N ₂ O). Urea has physical properties such as a molecular weight [g/mol] of 60.06, a melting point of 133-135° C., non-flammable, odorless, easily soluble in water, and a crystalline white solid, which is safe for the human body. Urea has the property of generating a negative heat of solution when dissolved in water. That is, in the latent heat storage material composition 1, the latent heat storage material 10 is sodium acetate trihydrate, and when urea dissolves in sodium acetate trihydrate water, the urea absorbs heat from the outside. An endothermic reaction occurs.

The second additive 30 (second melting point modifier) is a substance belonging to sugar alcohol, and in this embodiment, it is erythritol (C ₄ H ₁₀ O ₄ ). Erythritol is a naturally occurring substance that is a kind of sugar alcohol, and is a substance that is highly safe for the human body as it is also used as a food additive. Erythritol alone has a molecular weight [g/mol] of 122.12, a physical property that undergoes a phase change between a liquid phase and a solid phase, and is a solid that is readily soluble in water at a temperature lower than the melting point of 121 ° C., Above its melting point, it is liquid.

The supercooling inhibitor 40 is histidine (supercooling inhibitor 40A), which is a kind of amino acid. Alternatively, the supercooling inhibitor 40 is a phosphate hydrate containing metal ions, and in this embodiment, disodium hydrogen phosphate dodecahydrate (Na ₂ HPO _{4.12H 2} O) (supercooling prevention agent 40B).

Histidine is one of basic amino acids, has a molecular weight [g/mol] of 155.16, and is a safe substance for the human body. L-histidine is a colorless crystal soluble in water.

In addition, the physical properties of disodium hydrogen phosphate dodecahydrate are: hydration number 12, molecular weight [g/mol] 358.19, nonflammable, odorless, soluble in water, safe for the human body, white It is a crystalline solid with a melting point of about 35°C.

Next, as an experiment for confirming the solidification behavior of the latent heat storage material composition 1 due to a phase change, the latent heat storage material compositions according to Examples 1 and 2 and the latent heat storage material according to Comparative Example 1 were tested. , using each sample of the latent heat storage material composition according to Comparative Example 2, three kinds of verification tests regarding its solidification were conducted. FIG. 2 is a table summarizing the content ratio of the constituent components of the latent heat storage material composition and the measurement results of the melting point and heat storage amount by DSC for Examples 1 and 2 and Comparative Examples 1 and 2 thereof.

(Example 1)
In the latent heat storage material composition 1A(1) according to Example 1, as shown in FIG. urea (first additive 20) 30.4 wt% as an agent, erythritol (second additive 30) 19.0 wt% as a second melting point regulator, and histidine (supercooling inhibitor 40A) 5 .0 wt% is added.

(Example 2)
The latent heat storage material composition 1B(1) according to Example 2 includes 43.2 wt % of sodium acetate trihydrate (latent heat storage material 10) as a main component, and urea as a first melting point adjuster (first Additive 20) 28.8 wt%, erythritol (second additive 30) 18.0 wt% as a second melting point regulator, and disodium hydrogen phosphate dodecahydrate (supercooling inhibitor 40B ) 10.0 wt%.

(Comparative example 1)
The latent heat storage material according to Comparative Example 1 is sodium acetate trihydrate alone (100 wt %).

(Comparative example 2)
The latent heat storage material composition according to Comparative Example 2 is composed of 48.0 wt% of sodium acetate trihydrate as a main component, 32.0 wt% of urea as a first melting point adjuster, and a second melting point adjuster. 20.0 wt% of certain erythritol is added.

<Verification test 1>
First, verification test 1 will be described. In Verification Test 1, the latent heat storage material compositions according to Examples 1 and 2, the latent heat storage material according to Comparative Example 1, and the latent heat storage material composition according to Comparative Example 2 were tested as latent heat storage materials. A total weight of 50 g was prepared for each composition. Specifically, all kinds of raw materials, which are constituents of the sample, are weighed so that the total weight of the sample is 50 g. Then, the contained raw materials are mixed in an aluminum pack. Next, the aluminum pack containing the raw material is immersed in a water bath and heated at 60 ° C., and the contents (sample) in the aluminum pack except for the latent heat storage material according to Comparative Example 1 are completely melted. let me Since the latent heat storage material according to Comparative Example 1 causes a supercooling phenomenon when completely melted, the heating was stopped in a state where there was a slight unmelted portion in the aluminum pack.

Next, in order to solidify the sample in the aluminum pack, after setting the aluminum pack containing the sample in the constant temperature bath, it was cooled to 0°C in the constant temperature bath. The sample was then heated from 0°C to 40°C at a heating rate of 10°C/hour. Thereafter, heat was stored in the sample by holding the sample at a temperature of 40° C. for 6 hours. Then, after 6 hours from the start of heat retention of the sample, the sample kept at 40° C. was cooled to 0° C. at a cooling rate of 10° C./hour, and the behavior of heat dissipation from the sample was observed. The temperature of the sample was measured with a thermocouple attached to the surface of the aluminum pack containing the sample.

<Results of verification test 1>
FIG. 3 shows the results of Verification Test 1, and is a graph collectively showing changes in the state of latent heat storage material compositions according to Examples 1 and 2 and Comparative Examples 1 and 2 thereof. As shown in FIG. 3, in Examples 1 and 2, the temperature rise of the sample is slower than that of Comparative Examples 1 and 2 at around 20° C. during the temperature rise, and a behavior in which the sample starts to melt was observed. rice field. On the other hand, in Example 1, at around 12° C. when the temperature was lowered, the drop in temperature of the sample was slower than in Comparative Examples 1 and 2, and the behavior of the sample starting to solidify was observed. Also, in Example 2, the temperature drop of the sample was slower than in Comparative Examples 1 and 2 at around 15° C. when the temperature was lowered, and it was observed that the sample started to solidify.

On the other hand, in Comparative Example 1, since the latent heat storage material (sodium acetate trihydrate) is always in a solid state, no temperature change suggesting a phase change was observed. Also in Comparative Example 2, no temperature change suggesting a phase change was observed during both the temperature rise and the temperature fall. Regarding the results of Comparative Example 2, it is considered that one of the reasons for the results of Comparative Example 2 is that the sample was not completely solidified even when the aluminum pack containing the sample was cooled to 0°C in the constant temperature bath. be done.

<Verification test 2>
Next, verification test 2 will be described. In the verification test 2, samples of the latent heat storage material compositions 1A and 1B according to Examples 1 and 2 were each weighed to a total weight of 30 g and placed in a 50 ml polypropylene bottle. Next, the bottle containing the sample was set in a constant temperature bath, and the inside of the constant temperature bath was maintained at a set temperature of 40° C., thereby completely melting the sample in the polypropylene bottle.

Next, in both Examples 1 and 2, after confirming that the sample in the polypropylene bottle was completely melted, the polypropylene bottle containing the sample was placed in a constant temperature bath set at 20 ° C. , held for 3 hours. After 3 hours had passed, it was visually confirmed whether or not the sample in the polypropylene bottle had solidified. That is, it was observed whether the sample was solidified at 20°C.

At this time, if the sample is not solidified, the set temperature in the constant temperature bath is lowered from 20 ° C. (previous set temperature) by 1 ° C. to 19 ° C. (next set temperature), and then the sample is 19 ° C. It was observed whether it solidified in the state. In the verification test 2, the operation of lowering the temperature in the constant temperature bath by 1°C from the previous set temperature to the next set temperature and the confirmation of the state of the sample are repeated until the solidification of the sample is confirmed. Verification test 2 was terminated when the coagulation of the sample was confirmed.

<Results of verification test 2>
In Example 1, the sample was completely solidified under the condition that the set temperature in the constant temperature bath was 18°C. Moreover, in Example 2, the sample was completely solidified under the condition that the set temperature in the constant temperature bath was 15°C.

Here, like the supercooling inhibitor 40A (histidine) contained in the latent heat storage material composition 1A according to Example 1, among a plurality of kinds of substances belonging to amino acids, the latent heat storage material composition according to the present invention In order to ascertain the existence of substances suitable as anti-supercooling agents, in addition to Verification Test 2, an investigative test was conducted in advance to determine the suitability of anti-supercooling agents for a total of eight substances including histidine.

In the investigation test, sodium acetate trihydrate (latent heat storage material 10), which is the main component, urea (first additive 20), which is the first supercooling inhibitor, and the second supercooling inhibitor, A latent heat storage material composition containing a certain erythritol (second additive 30) was prepared. In addition, all 8 substances were selected from substances belonging to amino acids and used as supercooling inhibitors. The substances selected were histidine (test 1), glutamine (test 2), cysteine hydrochloride monohydrate (test 3), glutamic acid (test 4), aspartic acid (test 5), asparagine monohydrate (test 6). , alanine (test 7), and arginine (test 8). Eight kinds of latent heat storage material compositions were prepared for each of these substances, and Tests 1 to 8 were conducted using the samples.

<Test method>
In the investigation test, all eight types of latent heat storage material compositions prepared for each of the amino acid substances described above were weighed to a total weight of 20 g and put into a polypropylene bottle with a capacity of 50 ml. Next, the bottle containing the sample was set in a constant temperature bath, and the inside of the constant temperature bath was maintained at a set temperature of 40° C., thereby completely melting the sample in the polypropylene bottle.

Next, after confirming that the sample in the polypropylene bottle was completely melted, the polypropylene bottle containing the sample was held in a constant temperature bath set at 20°C for 3 hours. After 3 hours had passed, it was visually confirmed whether or not the sample in the polypropylene bottle was solidified at the set temperature of 20°C in the constant temperature bath. Furthermore, it was visually confirmed whether or not the sample in the polypropylene bottle was solidified even under the conditions of 19° C. and 18° C., which were sequentially lowered by 1° C. from the set temperature of 20° C. in the constant temperature bath.

<Conditions of investigation test>
・Latent heat storage material 10; sodium acetate trihydrate ・First additive 20; urea (first melting point adjuster)
- Second additive 30; erythritol (second melting point modifier)
Mixing ratio (wt%) of the latent heat storage material 10, the first additive 20, the second additive 30, and the supercooling inhibitor
Sodium acetate trihydrate: urea: erythritol: supercooling inhibitor = 45.6: 30.4: 19.0: 5.0
· Supercooling inhibitor; histidine (test 1), glutamine (test 2), cysteine hydrochloride monohydrate (test 3), glutamic acid (test 4), aspartic acid (test 5), asparagine monohydrate (test 6) ), alanine (test 7), and arginine (test 8)

<Results of investigation test>
FIG. 7 is a table showing the results of an investigation test in which the phase state of a latent heat storage material composition using an amino acid as a supercooling inhibitor was visually confirmed for each substance forming the supercooling inhibitor. In the middle, the "o" mark indicates that the melt has solidified, and the "x" mark indicates that the melt has not solidified and remains as it is. In the case of histidine, in addition to the results of Example 1 described above in Verification Test 2, as shown in FIG. Solidification was not confirmed, but solidification of the sample was confirmed under the condition of the set temperature of 18°C.

On the other hand, in the case of substances other than glutamine, cysteine hydrochloride monohydrate, glutamic acid, aspartic acid, asparagine monohydrate, alanine, arginine, and histidine, the set temperatures in the thermostat are 20°C, 19°C, and 18°C. Solidification of the sample could not be confirmed at any temperature.

<Verification test 3>
Next, verification test 3 will be described. In verification test 3, the latent heat storage material compositions 1A and 1B according to Examples 1 and 2, the latent heat storage material according to Comparative Example 1, and the latent heat storage material composition according to Comparative Example 2 were tested for each heat storage material. Approximately 10 mg of a sample was collected from the sample, and a well-known differential scanning calorimeter (DSC) was used to measure approximately 10 mg of the sample placed on the sample stage with nitrogen at 50 ml/min. The melting point of the sample and the amount of latent heat stored in the sample were measured under the condition that the sample was exposed to an atmosphere gas of 100 rpm and kept in a sealed state.

Specifically, in Examples 1 and 2, the sample of the latent heat storage material composition 1 (1A, 1B) was completely solidified, and the sample was heated from 20°C to 0°C for measurement by DSC. 2° C./min. and the sample was held at 0°C for 40 minutes. After that, the sample was heated at 2°C/min. from 0°C to 40°C. and the sample was held at 40°C for 20 minutes. Next, after 20 minutes had passed from the start of temperature retention of the sample, the sample that had been kept at 40°C was cooled to 0°C at 2°C/min. The sample was held at a temperature of 0°C for 40 minutes by cooling at a cooling rate of . With such a series of processes as one cycle, in Examples 1 and 2, the series of processes is repeated multiple times.

Further, in Comparative Example 1, the sample was heated at 2°C/min. from 30°C to 70°C. was heated at a temperature rising rate of , and the melting point and heat storage amount of the sample were measured while the temperature was rising. In addition, since Comparative Example 1 is a sample consisting of sodium acetate trihydrate (melting point 58° C.) alone, unlike Examples 1 and 2, sodium acetate trihydrate is likely to cause a supercooling phenomenon. , in Comparative Example 1, the temperature of the sample was not lowered from 70°C.

In Comparative Example 2, as in Examples 1 and 2, the sample of the latent heat storage material composition according to Comparative Example 2 was heated from 20° C. to 0° C. in order to perform measurement by DSC while the sample was completely solidified. °C at 2°C/min. was cooled at a cooling rate of . However, since the sample of Comparative Example 2 did not solidify even at 0° C., the measurement of the melting point and heat storage amount of the sample by DSC was abandoned.

<Results of verification test 3>
FIG. 4 is a graph showing the melting point peak and heat storage amount of the latent heat storage material composition according to Example 1, and is a graph showing experimental results when histidine is used as a supercooling inhibitor. FIG. 5 is a graph showing the melting point peak and heat storage amount of the latent heat storage material composition according to Example 2, and the experiment in which disodium hydrogen phosphate dodecahydrate was used as the supercooling inhibitor. It is a graph which shows a result. In the case of Examples 1 and 2, FIGS. 4 and 5 show the results of the melting point and heat storage amount measured while the sample was heated from 0° C. to 40° C. in the first cycle. ing. FIG. 6 is a graph showing the melting point peak and heat storage amount of the latent heat storage material according to Comparative Example 1, and is a graph showing experimental results when neither the melting point adjuster nor the supercooling inhibitor was added.

In the graphs shown in FIGS. 4 to 6, the scale on the left side of the vertical axis indicates the temperature of the sample. The scale on the right side of the vertical axis indicates the amount of heat stored or released from the sample per unit time. Indicates the amount of heat dissipated. In addition, in the graph of the amount of heat that changes over time, in the "negative" region, the absolute value of the amount of heat temporarily increases, and the temperature of the sample corresponding to the time t when it reaches the maximum value (peak top) At T (defined as the melting point), the amount of heat absorbed per unit time is maximized. The latent heat of fusion of a sample is the peak area S (in figures such as FIG. 4) obtained by integrating the heat quantity between the start time and the end time of the endothermic peak (melting peak) in the heat quantity diagram. , shaded area).

On the contrary, in the graph of the amount of heat that changes over time, in the "positive" area, the absolute value of the amount of heat temporarily increases and reaches the maximum value (peak top) at time t. When the temperature T (defined as the freezing point) is reached, the heat release amount per unit time is maximized. The solidification latent heat of a sample is indicated by the size of the peak area S obtained by integrating the heat quantity between the start time and the end time of the heat release peak (solidification peak) in the heat quantity diagram. The unit of the heat quantity is [W/g] and the unit of the mass of the sample is [mg], but after performing unit conversion, the unit of the heat storage amount is set to [kJ/kg]. Further, the graphs shown in FIGS. 4 to 6 do not show the solidification peak and the amount of heat release.

Next, the results of verification test 3 will be described. In the latent heat storage material composition 1A according to Example 1, as shown in FIG. 4, the temperature Ta corresponding to the melting peak time t1 was 24.9° C., and the heat storage amount Sa was 153 kJ/kg.

In the latent heat storage material composition 1B according to Example 2, as shown in FIG. 5, the temperature Tb corresponding to the melting peak time t1 was 22.4° C., and the heat storage amount Sb was 169 kJ/kg.

On the other hand, in the latent heat storage material according to Comparative Example 1, as shown in FIG. 6, the temperature Tc corresponding to the melting peak time t1 was 61.3° C., and the heat storage amount Sc was 284 kJ/kg.

<Discussion>
In the case of Comparative Example 1, neither the melting point adjuster nor the supercooling inhibitor was added, and the melting peak of the latent heat storage material was 61.3°C, which generally coincided with the well-known melting point of sodium acetate trihydrate alone, which was 58°C. It has become.

On the other hand, in Example 1, the melting peak of the latent heat storage material composition 1A was 24.9°C, which is lower than that in Comparative Example 1 by 36.4°C. In this way, the reason why the melting peak can be lowered by 36.4 ° C. is that urea (first melting point modifier) as the first additive 20 and erythritol (second melting point modifier) as the second additive 30 melting point adjuster) is added together with sodium acetate trihydrate (latent heat storage material 10). In addition, since histidine (supercooling inhibitor 40A) is added to the latent heat storage material composition 1A, the supercooling phenomenon is effectively suppressed with respect to sodium acetate trihydrate. In the latent heat storage material composition 1A, latent heat is considered to be stored due to a phase change from the liquid phase to the solid phase.

Moreover, in Example 2, the melting peak of the latent heat storage material composition 1B was 22.4° C., which is 38.9° C. lower than that in Comparative Example 1. In this way, the reason why the melting peak can be lowered by 38.9 ° C. is that urea (first melting point modifier) as the first additive 20 and erythritol (second melting point modifier) as the second additive 30 melting point adjuster) is added together with sodium acetate trihydrate (latent heat storage material 10). In addition, since disodium hydrogen phosphate dodecahydrate (supercooling inhibitor 40B) is added to the latent heat storage material composition 1B, the supercooling phenomenon does not occur with respect to sodium acetate trihydrate. is effectively suppressed, and it is considered that the latent heat is stored in the latent heat storage material composition 1B due to the phase change from the liquid phase to the solid phase.

Next, functions and effects of the latent heat storage material composition 1 according to the present embodiment will be described.

A latent heat storage material composition 1 according to the present embodiment includes a latent heat storage material 10 containing sodium acetate trihydrate as a main component, and a melting point adjuster for adjusting the melting point of the latent heat storage material 10. The melting point adjuster In the latent heat storage material composition containing urea as the first additive 20, the melting point adjuster contains a substance belonging to sugar alcohol as the second additive 30 together with the first additive 20. It contains a supercooling inhibitor 40 that promotes the induction of crystallization of the latent heat storage material 10, and the supercooling inhibitor 40 is histidine (supercooling inhibitor 40A) or, for example, disodium hydrogen phosphate. It is characterized by being at least one of phosphate hydrate containing metal ions such as dihydrate (supercooling inhibitor 40B).

Due to this feature, even if the latent heat storage material composition 1 contains sodium acetate trihydrate as the latent heat storage material 10 as a main component, the latent heat storage material composition 1 is set at the melting point of the latent heat storage material 10 of 58°C. For example, the melting point can be lowered by 30°C or more. In addition, sodium acetate trihydrate is a latent heat storage material that is particularly prone to supercooling among latent heat storage materials made of inorganic salt hydrates. , the supercooling inhibitors 40A and 40B can effectively suppress it. Moreover, as in Examples 1 and 2 of Verification Test 3, between the temperature at which the latent heat storage material composition 1 (1A and 1B) is completely solidified and the temperature at which it is completely melted, the heating operation and Phase change between the liquid phase and the solid phase occurs more reliably even when a series of processes involving temperature-lowering operations are repeated multiple times.

Therefore, according to the latent heat storage material composition 1 according to the present embodiment, even when sodium acetate trihydrate, which is the latent heat storage material 10, is the main component, the melting point can be lowered to the level of 20°C. There is an excellent effect of being there.

Further, the latent heat storage material composition 1 according to the present embodiment is characterized in that the substance belonging to sugar alcohol (second additive 30) is erythritol.

Due to this feature, the melting point of the latent heat storage material composition 1 is, for example, about 30° C. lower than the 58° C. melting point of sodium acetate trihydrate, which is the main component. It is a suitable melting point modifier. Moreover, since erythritol itself has heat storage and heat dissipation performance for storing heat and dissipating it, and has excellent physical properties as a heat storage material, the addition of the second additive 30 makes the latent heat storage material composition 1 as a whole Even if the blending ratio of the latent heat storage material 10 to the weight of the latent heat storage material 10 is halved compared to the latent heat storage material 10 alone, the latent heat storage material composition 1 has a heat storage amount that effectively suppresses a significant decrease.

Further, in the latent heat storage material composition 1 according to the present embodiment, the supercooling inhibitor 40 is histidine (supercooling inhibitor 40A) or disodium hydrogen phosphate dodecahydrate (supercooling inhibitor 40B). The melting point of the latent heat storage material 10 is adjusted to 20 degrees.

Due to this feature, when the latent heat storage material composition 1 is arranged, for example, on walls, floors, or the like for a house with energy saving measures, the latent heat storage material composition 1 stores heat from sunlight during the daytime. As a result, it becomes possible to suppress an increase in the room temperature, and to suppress a decrease in the room temperature by radiating the stored latent heat at night. Therefore, the latent heat storage material composition 1 can contribute to the provision of a comfortable living space with a room temperature in the 20° C. range.

On the other hand, when the latent heat storage material is paraffin-based, the heat storage amount of the latent heat storage material differs depending on the material, so the heat storage amount per volume is generally 100 to 200 kJ/kg, although a general comparison cannot be made. As shown in FIG. 2, the heat storage amount of the latent heat storage material composition 1 is about 150 to 170 kJ/kg, which is about the same as the paraffin-based latent heat storage material at the same volume ratio. Unlike , the latent heat storage material composition 1 itself is not flammable, and there is no need to take safety measures against fire, so the latent heat storage material composition 1 is easy to use.

Moreover, the latent heat storage material composition 1 contains sodium acetate trihydrate (latent heat storage material 10), urea (first additive 20), erythritol, and other substances belonging to sugar alcohols (second additive 30). First of all, the heat storage material is highly safe because the entire constituent components are mainly composed of highly safe substances that are also used as food additives.

In the above, the present invention has been described with reference to Examples 1 and 2 of the embodiment and Comparative Examples 1 and 2, but the present invention is not limited to Examples 1 and 2 of the above-described embodiment. Appropriate changes can be applied without departing from the scope of the invention.

For example, in the embodiment, in the case of Example 1 in which histidine is used as the supercooling inhibitor 40, the mixing ratio (wt%) of sodium acetate trihydrate, urea, erythritol, and histidine is 45.6. :30.4:19.0:5.0, the melting point of the latent heat storage material composition 1A was adjusted to around 25.degree. However, the blending ratio of sodium acetate trihydrate, urea, erythritol, and histidine is not limited to that in Example 1, and is, for example, 20 to 35° C. It can be changed as appropriate according to the desired temperature to be adjusted within the range of.

In the embodiment, in the case of Example 2 using disodium hydrogen phosphate dodecahydrate as the supercooling inhibitor 40, sodium acetate trihydrate, urea, erythritol, and disodium hydrogen phosphate The melting point of the latent heat storage material composition 1B was adjusted to around 22°C by setting the mixing ratio (wt%) with the dodecahydrate to 43.2:28.8:18.0:10.0. . However, the mixing ratio of sodium acetate trihydrate, urea, erythritol, and disodium hydrogen phosphate dodecahydrate is not limited to that in Example 2, and the melting point of the latent heat storage material composition On the other hand, it can be changed appropriately according to the desired temperature to be adjusted within the range of 20 to 35° C., for example.

In addition, in the embodiment, the latent heat storage material composition 1 in which the first additive 20, the second additive 30, and the supercooling inhibitor 40 are added to the latent heat storage material 10 is mentioned. In addition to these, the composition may be a composition to which additives such as thickeners and colorants are added, if necessary.

1, 1A, 1B latent heat storage material composition 10 latent heat storage material 20 first additive (urea, first melting point adjuster)
30 second additive (erythritol, second melting point modifier)
40, 40A, 40B supercooling inhibitor

Claims (3)

A latent heat storage material containing sodium acetate trihydrate (CH ₃ COONa·3H ₂ O) as a main component, and a melting point adjuster for adjusting the melting point of the latent heat storage material. In a latent heat storage material composition containing urea as an agent and a substance belonging to sugar alcohol as a second additive ,
containing a supercooling inhibitor that promotes the induction of crystallization of the latent heat storage material, wherein the supercooling inhibitor is histidine (C ₆ H ₉ N ₃ O ₂ ) ;
A latent heat storage material composition characterized by: In the latent heat storage material composition according to claim 1 ,
the substance belonging to the sugar alcohol is erythritol (C ₄ H ₁₀ O ₄ );
A latent heat storage material composition characterized by: In the latent heat storage material composition according to claim 1 or 2 ,
The melting point of the latent heat storage material is adjusted to 20 degrees,
A latent heat storage material composition characterized by:

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