JP2011148949A - Heat storage material composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat storage material composition meltable at 85°C and promptly coagulating at 25°C, which consists mainly of threitol. <P>SOLUTION: There are provided the heat storage material composition consisting mainly of threitol with added water in an amount of 2.5-4.0 wt.%, and the heat storage material composition consisting mainly of threitol with added water-soluble sugar alcohol other than threitol or saturated solutions of a sugar compound in an amount of 3.0-4.0 wt.%, instead of water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a latent heat storage material composition suitable for storing heat at a relatively low temperature (about 85 to 100 ° C.) using heat radiation from an automobile engine or heat from engine exhaust gas as a heat source.

  In order to effectively use thermal energy, a heat storage material capable of temporarily storing thermal energy has been developed. Sugar alcohols such as threitol and erythritol are attracting attention as latent heat storage type heat storage materials because of their high safety to the human body and the environment (Patent Documents 1 to 6).

  Patent Document 3 discloses a heat storage material composition comprising a sugar alcohol and an aqueous solution in which a water-soluble salt is dissolved. The invention of Patent Document 3 describes the problem of the prior art that sugar alcohols are dissolved by water added to lower the melting point of sugar alcohols and the amount of latent heat is reduced. This is an invention to be solved by using an aqueous solution of a water-soluble salt. In patent document 3, 3-50 mass% is described with respect to the thermal storage material composition whole quantity as a compounding quantity of the aqueous solution which melt | dissolved water-soluble salt, and it describes that about 5-60 mass% is preferable. .

  Patent Document 4 describes a heat storage material composition comprising sugar alcohol or an inorganic hydrated salt, water, and water-insoluble microfibers. The invention of Patent Document 4 is provided as a technique for solving the problem of the prior art that the heat storage material after heat collection is solidified and fluidized. Further, it is described that by adding water, the fluidity of the entire latent heat storage material can be improved, and the melting point of the latent heat storage material can be easily adjusted. According to Patent Document 4, in order to set the melting point of erythritol to 60 to 90 ° C., it is described that 45 to 25% by weight of water is blended with respect to the total weight of the composition.

  Patent Document 5 describes a heat storage material composition having a melting point of −5 ° C. or more and less than 0 ° C., comprising 6 to 25% by weight of erythritol and 75 to 94% by weight of water.

  Patent Document 6 describes a heat storage material composition containing thritol and meso-erythritol. In the invention of Patent Document 6, meso-erythritol is added for the purpose of adjusting the melting point of threitol. According to the example of Patent Document 6, the melting point of a composition in which meso-erythritol and threitol were blended at a weight ratio of 10:90 was 85.1 ° C., and the melting point of sole thoritol alone (D-form 92.1 ° C., Lower than L-form 92.4 ° C). Nevertheless, the latent heat of fusion is kept high.

JP-T 63-500946 JP-A-5-32963 JP 2008-95042 A JP 2007-321029 A Japanese Patent Laid-Open No. 10-279931 JP 2000-87020 A

  In order to store heat at a relatively low temperature (about 85 to 100 ° C.) such as cooling water using heat from the engine of an automobile or heat from engine exhaust gas as a heat source, a heat storage material composition that can be melted at about 85 ° C. is required. . And it is necessary to be a heat storage material composition that can quickly solidify and release heat at around 25 ° C.

  Since threitol has a melting point in the vicinity of 92 ° C., it is necessary to lower the melting point for the above use. Threitol solidifies near 25 ° C., but has a problem that the solidification rate is slow.

  Patent Document 3 describes that about 5 to 60% by mass of water is preferably added to the sugar alcohol heat storage material composition, and Patent Document 4 describes that 45 to 25% by weight of water is added to the sugar alcohol heat storage material composition. Is described. In these documents, water is added to lower the melting point of the sugar alcohol. However, Patent Documents 3 and 4 only describe the heat release characteristics (coagulation characteristics) of the composition using erythritol as the latent heat storage material. Regarding the effect of the amount of water added when using threitol as the sugar alcohol, It has not been studied at all. The melting point of erythritol is 123 ° C. The heat dissipation characteristics of sleyitol, which has a lower melting point than erythritol, have not been confirmed.

  When the present inventors confirmed by the experiment described in this specification, there is a problem that when 5 wt% or more of water is added to threitol, the solidification rate at 25 ° C. is remarkably slowed. Furthermore, when the amount of water added exceeds 15 wt%, there is a problem that thritol cannot phase change and cannot store heat using latent heat.

  A structure containing a heat storage material composition in which a corrosive substance such as salt is added to water as in Patent Document 3 needs to be subjected to corrosion countermeasures. In the heat storage material composition of Patent Document 4, water-insoluble fine fibers may be separated in the process of repeating solidification and melting.

  According to the invention of Patent Document 6, by adding erythritol, the melting point (near 92 ° C.) of threitol can be lowered to around 85 ° C. while maintaining the latent heat of fusion. In addition, the latent heat of fusion is maintained. However, this technique does not solve the problem that the solidification rate of thritol is slow.

  Then, this invention makes it the problem which should be solved to provide the thermal storage material composition which has a threitol as a main component which can melt | dissolve at 85 degreeC and can solidify rapidly at 25 degreeC.

  The inventors of the present invention are that a heat storage material composition mainly composed of thritol to which water is added in an amount of 2.5 to 4.0 wt% can be melted at 85 ° C. and solidified at 25 ° C., and It was found that the coagulation time was short. The inventors of the present invention also provide a heat storage material composition containing, as a main component, threitol added with a saturated aqueous solution of another sugar alcohol or sugar compound in an amount of 3.0 to 4.0 wt% instead of water. In addition to the advantageous effect of addition, it has been found that it has the effect of suppressing the decrease in latent heat of fusion.

The present invention includes the following inventions.
(1) including sreitor and water,
The heat storage material composition whose water content is 2.5 to 4.0 wt% with respect to the sum of the content of thritol and water.

(2) It contains thritol, a water-soluble sugar alcohol or saccharide compound other than thritol, and water, and the sum of the contents of the saccharide alcohol or saccharide compound and water is thritol, saccharide alcohol or saccharide compound and water. The content of the sugar alcohol or sugar compound is 3.0 to 4.0 wt% with respect to the sum of the contents, and the total amount of water and saturation of the sugar alcohol or sugar compound at a temperature in the range of 25 to 30 ° C. A heat storage material composition in an amount capable of forming an aqueous solution.

(3) Threitol, a water-soluble sugar alcohol or sugar compound other than threitol, and water, and the sum of the contents of the sugar alcohol or sugar compound and water is thritol, the sugar alcohol or sugar compound and water. The content of the sugar alcohol or sugar compound is 35 to 50 wt% with respect to the sum of the content of the sugar alcohol or sugar compound and water. A heat storage material composition.

(4) The heat storage material composition according to (2) or (3), wherein the sugar alcohol or sugar compound is erythritol.

  The heat storage material composition of the present invention comprising thritol as a main component can be melted at 85 ° C. and can be rapidly solidified at 25 ° C.

FIG. 1 shows the relationship between the water content in the D-threitol composition and the coagulation time. FIG. 2 shows the relationship between the water content in the D-threitol composition and the latent heat reduction rate. FIG. 3 shows the relationship between the content of the D-erythritol saturated aqueous solution in the D-threitol composition and the coagulation time. FIG. 4 shows the relationship between the content of the saturated D-erythritol aqueous solution in the D-threitol composition and the latent heat reduction rate.

  The first heat storage material composition of the present invention includes slateol and water, and the water content is 2.5 to 4.0 wt% with respect to the sum of the slateol and water content. It is.

  As the threitol, any of D-threitol, L-threitol, and DL-threitol may be used.

  The water content is 2.5 to 4.0 wt% with respect to the sum of the content of thritol and water. When the water content is lower than 2.5 wt%, it is not preferable because it does not melt at 85 ° C. and the coagulation time at 25 ° C. is long. When the water content is higher than 4.0 wt%, it is not preferable because the solidification time at 25 ° C. is long. Since the 1st heat storage material composition of this invention has very little content of water, it is preferable also in the point that a special pressure | voltage resistant structure is unnecessary for the heat storage tank which accommodates the said composition.

  The manufacturing method of the 1st heat storage material composition of this invention is not specifically limited. For example, it can be produced by mixing thritol and water under conditions where thritol melts.

  The 1st heat storage material composition of this invention may contain the other component in the range which does not inhibit the effect of this invention as a heat storage material composition. The total amount of threitol and water blended in the above proportion is preferably 70 wt% or more, preferably 80 wt% or more, and preferably 90 wt% or more of the total weight of the heat storage material composition. 95 wt% or more is particularly preferable, and 100 wt% is most preferable. That is, the first heat storage material composition of the present invention is a composition mainly composed of seleitol having a predetermined composition and water, and particularly preferably a composition substantially comprising sreitol and water having a predetermined composition. is there. Particularly preferred is a composition composed of thritol and water having a predetermined composition and containing no other components. The heat storage material composition preferably does not contain water-soluble salts such as alkali metal salts and alkaline earth metal salts used in Patent Document 3. This is because when such a salt is contained, the structure for housing the heat storage material needs to be resistant to corrosion. Furthermore, it is preferable that the heat storage material composition does not contain water-insoluble fibers as used in Patent Document 4. This is because water-insoluble fibers may be separated from thritol and water.

  The second heat storage material composition of the present invention comprises threitol, a water-soluble sugar alcohol or sugar compound other than threitol, and water, and the sum of the contents of the sugar alcohol or sugar compound and water is The total amount of water at a temperature of 3.0 to 4.0 wt% with respect to the sum of the sugar alcohol or sugar compound and water content, and the sugar alcohol or sugar compound content is in the range of 25 to 30 ° C. And a heat storage material composition in an amount capable of forming a saturated aqueous solution of the sugar alcohol or sugar compound.

  Threitol that can be used is as described above for the first heat storage material composition.

  Examples of water-soluble sugar alcohols or sugar compounds other than threitol include erythritol, mannitol, palatinose, and lactose. The sugar compound includes saccharides such as monosaccharides, disaccharides, and trisaccharides, and derivatives thereof. Sugar alcohol is particularly preferable, and erythritol is particularly preferable because erythritol is an isomer of threitol and does not separate from threitol even after repeated melting and coagulation. As erythritol, D-erythritol, L-erythritol, DL-erythritol, meso-erythritol can be used. Two or more water-soluble sugar alcohols or sugar compounds can be used in combination as a “water-soluble sugar alcohol or sugar compound other than threitol”.

  In the present invention, the content of the sugar alcohol or the sugar compound may form a saturated aqueous solution of the sugar alcohol or the sugar compound with the total amount of water contained in the composition at any temperature in the range of 25 to 30 ° C. It is the amount that can be. Examples of the content of the sugar alcohol or sugar compound that makes it possible to achieve an effect equivalent to this amount include 35 to 50 wt% with respect to the sum of the contents of the sugar alcohol or sugar compound and water. This content is particularly preferable when erythritol is used as the sugar alcohol. By setting the content of the sugar alcohol or sugar compound within this range, a decrease in latent heat is suppressed. This effect is considered to be due to the suppression of the decrease in the amount of heat caused by the dissolution of thritol in water.

  The sum of the content of the sugar alcohol or sugar compound and water is 3.0 to 4.0 wt% with respect to the sum of thritol, the sugar alcohol or sugar compound and water. When the sum of the content of the sugar alcohol or sugar compound and water is lower than 3.0 wt%, it is not preferable because it does not melt at 85 ° C. and the coagulation time at 25 ° C. becomes longer. When the sum of the content of the sugar alcohol or sugar compound and water is higher than 4.0 wt%, it is not preferable because the coagulation time at 25 ° C. is long. The second heat storage material composition of the present invention is also preferable in that a special pressure-resistant structure is not required for the heat storage tank containing the composition because the water content is very small.

  The manufacturing method of the 2nd heat storage material composition of this invention is not specifically limited. In the examples, a water-soluble sugar alcohol other than threitol or a saturated aqueous solution (37 wt%) of a sugar compound (erythritol) is prepared in advance, added to threitol, and mixed under conditions where threitol melts. The heat storage material composition was manufactured. However, the present invention is not limited to this. For example, a mixture in which thritol of a predetermined composition, a water-soluble sugar alcohol or sugar compound other than thritol, and water are mixed in an arbitrary order is mixed under a condition in which thritol melts. Thus, the second heat storage material composition can be manufactured.

  The 2nd heat storage material composition of this invention may also contain another component in the range which does not inhibit the effect of this invention as a heat storage material composition. The total amount of threitol and the sugar alcohol or sugar compound and water blended in the above proportion is preferably 70 wt% or more, preferably 80 wt% or more of the total weight of the heat storage material composition, 90 wt% % Or more, preferably 95 wt% or more, and most preferably 100 wt%. That is, the second heat storage material composition of the present invention is a composition comprising thritol of a predetermined composition and the sugar alcohol or sugar compound and water as main components, and particularly preferably, the thritol of the predetermined composition and the sugar alcohol. Or it is a composition which consists of a sugar compound and water substantially. Particularly preferred is a composition comprising thritol of a predetermined formulation and the sugar alcohol or sugar compound and water, which does not contain other components. Similarly to the first heat storage material composition, the second heat storage material composition also preferably does not contain water-soluble salts or water-insoluble fibers.

Example 1. Melting point lowering effect by adding water
1. The composition which consists of D-threitol and water whose water content rate (Wt%) with respect to the procedure composition whole quantity is the value shown in Table 1 was created. Each composition was encapsulated in D-threitol by heating and dissolving a mixture of D-threitol and water at a temperature higher than the melting point in the air, and then solidifying by cooling. Is. A 3 g solid sample of each composition was placed in a cylindrical sample bottle and sealed. In order to measure the sample temperature in the sample bottle, a K-type thermocouple was attached to the center of the bottom surface of the sample bottle.

(1) The sample bottle was placed in a constant temperature bath at 85 ° C., held for 24 hours, and visually checked for melting.
(2) The sample melted in (1) was cooled to 40 ° C. at room temperature.
(3) The sample was immersed in cooling water at 25 ° C. at a sample temperature of 40 ° C., and the solidification time (seconds) from nucleation to the end of phase change was measured.
(4) The amount of latent heat of each composition was measured by calorific value measurement (device used: RIGAKU Thermo plus DSC (8230), measurement method: DSC measurement). The latent heat reduction rate (%) was calculated by the following formula:

Latent heat reduction rate (%) = 100 × [{(latent heat amount of hydrate without hydrate) − (latent heat amount of hydrate with hydrate)} / (latent amount of latent heat of hydrate without hydrate)]

2. Melting and solidification evaluation Table 1 shows the water content (Wt%) of each composition, whether it can be melted at 85 ° C, and whether it can be solidified at 25 ° C.

  Compositions having a water content of 2.5 Wt% or more were found to melt at 85 ° C. However, coagulation at 25 ° C. was not observed in the composition having a water content of 10 Wt% or more.

3. Evaluation of solidification rate FIG. 1 shows the relationship between the water content in the D-threitol composition and the solidification time measured in (3). It was confirmed that the coagulation time was the shortest in the range of water content of 2.5 to 4.0 Wt%.

4). The latent heat evaluation Figure 2 shows the relationship between the measured, D- threitol water content in the composition and the latent heat loss rate in (4).
It was confirmed that the amount of latent heat decreased as the water content increased.

Example 2 Effect of adding D-erythritol saturated aqueous solution
1. Procedure The effect when a D-erythritol saturated aqueous solution (saturated aqueous solution at 25 ° C., D-erythritol 37 Wt% aqueous solution) was added to D-threitol instead of water in Example 1 was confirmed. A composition comprising D-threitol and a saturated aqueous solution of D-erythritol having a content (Wt%) of the saturated aqueous solution of D-erythritol based on the total amount of the composition shown in Table 2 was prepared. Each composition is prepared by heating and dissolving a mixture of D-threitol and a saturated aqueous solution of D-erythritol at a temperature higher than the melting point in the air, and then cooling and solidifying the mixture to form a saturated aqueous solution of D-erythritol. Encapsulated in D-threitol. A 3 g solid sample of each composition was placed in a cylindrical sample bottle and sealed.

  According to the same procedure as in Example 1, 85 ° C. melting possibility, 25 ° C. solidification possibility, 25 ° C. solidification time, and latent heat reduction rate were measured.

2. Melting and solidification evaluation Table 2 shows the water content (Wt%) of each composition, whether it can be melted at 85 ° C, and whether it can be solidified at 25 ° C.

  It was confirmed that a composition having a saturated D-erythritol aqueous solution content of 3.0 Wt% or more melts at 85 ° C. However, the composition having a D-erythritol saturated aqueous solution content of 10 Wt% or more was not solidified at 25 ° C.

3. Evaluation of Coagulation Rate FIG. 3 shows the relationship between the content of a saturated aqueous D-erythritol solution in the D-threitol composition and the coagulation time. It was confirmed that the coagulation time was the shortest when the content of the saturated aqueous D-erythritol solution was 2.5 to 4.0 Wt%. However, when the D-erythritol saturated aqueous solution content is 2.5 Wt%, it cannot be melted at 85 ° C. as described above.

4). Evaluation of latent heat amount FIG. 4 shows the relationship between the content of a saturated aqueous D-erythritol solution in the D-threitol composition and the rate of decrease in latent heat. For comparison, FIG. 4 also shows the relationship between the water content and the latent heat reduction rate obtained in Example 1 in an overlapping manner.

  It was confirmed that the decrease in latent heat amount can be suppressed at a content rate in the same range as the water content rate. In particular, it was confirmed that the D-erythritol saturated aqueous solution content is in the range of 3.0 to 4.0 Wt%, and the latent heat suppression effect is large.

Example 3 Thermal conductivity of D-threitol-water composition The solid thermal conductivity of the D-threitol-water composition having a water content of 2.5 Wt% was measured by a laser flash method.
The results are shown in Table 3.

  It was confirmed that the thermal conductivity of the D-threitol solid was improved by adding water. From this, it was estimated that the short solidification time (high solidification rate) of the D-threitol-water composition having a water content of 2.5 Wt% is due to the improvement of the thermal conductivity of the material.

Claims (4)

Including Threitol and water,
The heat storage material composition whose water content is 2.5 to 4.0 wt% with respect to the sum of the content of thritol and water. Including threitol, a water-soluble sugar alcohol or sugar compound other than threitol, and water,
The sum of the contents of the sugar alcohol or sugar compound and water is 3.0 to 4.0 wt% with respect to the sum of the contents of thritol, the sugar alcohol or sugar compound and water,
The heat storage material composition wherein the content of the sugar alcohol or sugar compound is an amount capable of forming a saturated aqueous solution of the sugar alcohol or sugar compound with the total amount of water at a temperature in the range of 25 to 30 ° C. Including threitol, a water-soluble sugar alcohol or sugar compound other than threitol, and water,
The sum of the contents of the sugar alcohol or sugar compound and water is 3.0 to 4.0 wt% with respect to the sum of the contents of thritol, the sugar alcohol or sugar compound and water,
The heat storage material composition in which the content of the sugar alcohol or sugar compound is 35 to 50 wt% with respect to the sum of the contents of the sugar alcohol or sugar compound and water.   The heat storage material composition according to claim 2 or 3, wherein the sugar alcohol or sugar compound is erythritol.

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