JPH10279931A - Heat storage material composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition capable of being easily prepared, because the melting point of the composition is stable in a specific range against changes in the concentration of the composition, capable of preventing the corrosion of metals, and useful in fields such as the cooling storage of foods by compounding erythritol and water in a specific ratio. SOLUTION: This heat storage material composition comprises (A) 6-25 wt.% of erythritol and (B) 75-94 wt.% of water, and has a melting point of from -5 deg.C to <0 deg.C. The heat storage material composition, if necessary, further contains (C) a supercooling-preventing agent such as silver iodide, potassium bromate or tripotassium phosphate in an amount of 0.01-3 pts.wt. per 100 pts.wt. of the total amount of the components A and B, and (D) a thickening agent such as a water-insoluble, water-absorbing resin or a water-soluble polymer in an amount of 0.1-5 pts.wt. per 100 pts.wt. of the total amount. The composition is used in the form of e.g. capsules to be charged into heat storage containers, shell-and tubes not requiring the heat storage container, crushed ice, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a heat storage material composition. More specifically, the present invention relates to a low-temperature heat storage material composition comprising erythritol and water and utilizing latent heat of fusion.

[0002]

2. Description of the Related Art A latent heat storage material has a high heat storage density and a constant phase change temperature as compared with a sensible heat storage material, and has been put to practical use taking advantage of the advantage that the heat extraction temperature is stable. . Ice, sodium sulfate decahydrate, calcium chloride hexahydrate, sodium acetate trihydrate and the like are known as latent heat storage materials. Above all, an ice heat storage system using midnight power has been widely put into practical use for cooling. Also,
A heat storage material composition using an eutectic composition of an inorganic salt and water having a melting point of 0 ° C. or less for blending an inorganic salt for use in industrial fields such as cooling and preserving fruits and foods has also been reported. (JP-A 1-245082). However, since the heat storage material composition having a melting point of -3 to -5 ° C. for extracting cold water at about 0 ° C. is adjusted by the mixing ratio of the inorganic salt, it is sensitive to a change in concentration and difficult to adjust. In addition, the water-based heat storage material composition containing an inorganic salt is corrosive to metals, and cannot be used in an ice-on-coil type or a shell-and-tube type.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide:
An object of the present invention is to provide a heat storage material composition which has a melting point around ° C., is stable in concentration change, and has no corrosiveness to metals.

[0004]

Means for Solving the Problems The present inventors have made intensive studies in view of the above problems, and as a result, have found that a composition comprising erythritol and water in a specific ratio is stable at a melting point of -3 ° C. Heading, the present invention has been reached. That is, the gist of the present invention is that erythritol 6 to 25% by weight and water 75 to 9
A heat storage material composition comprising 4% by weight and having a melting point of -5 ° C or more and less than 0 ° C.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is characterized in that a specific amount of erythritol is added to water. The content of erythritol is 6 to 25% by weight, preferably 7 to 20%.
% By weight. If the content of erythritol is less than 6% by weight, the melting point will not be stable at around -3 ° C and will not show a clear melting point. When the content of erythritol is more than 25% by weight, erythritol is crystallized due to solubility and the composition is not uniform, and also the heat storage amount is reduced.

[0006] The heat storage material composition of the present invention may contain a supercooling inhibitor in order to prevent a so-called supercooling phenomenon that does not crystallize even when cooled to below the melting point. Examples of the supercooling inhibitor include silver iodide, copper sulfide, potassium bromate, tripotassium phosphate, calcium phosphate, ice nucleating bacteria, and cholesterol, preferably silver iodide, potassium bromate, and tripotassium phosphate. Is used.
The amount of the supercooling inhibitor is usually 0.01 to 3 parts by weight based on 100 parts by weight of erythritol and water in total.

The heat storage material composition of the present invention may contain a water-insoluble water-absorbent resin and / or a water-soluble polymer as a thickener. Examples of the water-insoluble water-absorbent resin include crosslinked sodium polyacrylate, sodium acrylate-vinyl alcohol copolymer, saponified polyacrylonitrile polymer, hydroxyethyl methacrylate polymer,
Polyvinyl alcohol crosslinked polymer, maleic anhydride polymer, polyethylene glycol diacrylate crosslinked polymer, starch-acrylic acid graft polymer, starch
Examples of the acrylonitrile graft polymer hydrolyzate, crosslinked carboxymethyl cellulose, cellulose-acrylonitrile graft polymer, and water-soluble polymer include carboxymethyl cellulose, acrylamide, and alginates. The compounding amount of the thickener is usually 0.1 to 5 parts by weight based on 100 parts by weight of erythritol and water in total.

Also, antioxidants such as phenols, amines and hydroxyamines, metal corrosion inhibitors such as chromates, polyphosphates and sodium nitrite, sodium benzoate, 2,6-di-t- Preservatives such as butylhydroxytoluene may be included. The method for preparing the heat storage material composition of the present invention is not particularly limited, but it is sufficient that erythritol, water, and additives are mixed as needed and uniformly dispersed. In order to more uniformly disperse, a method in which the heat storage material composition is heated to 40 to 70 ° C. and stirred and mixed is exemplified.

Examples of the method of using the heat storage material composition of the present invention include a capsule type in which the heat storage container is filled with the heat storage material composition, a shell and tube type which does not require a heat storage container, and a crush ice type. In the capsule type, the heat storage material composition is injected into a heat storage container such as a capsule,
It is obtained by sealing the heat storage container. Examples of the material of the capsule include metals such as iron and aluminum, and plastics such as high-density polyethylene, polypropylene, and polycarbonate. High-density polyethylene is preferable. The shape of the capsule is not particularly limited, and examples thereof include a sphere, a plate, a pipe, a constricted cylinder, a twin sphere, and a corrugated plate, and are appropriately selected depending on the application. The shell and tube type is a method in which the shell is filled with the heat storage material composition of the present invention, an antifreeze such as brine is flowed through the tube side, and the heat storage material is frozen around the tube. The crush ice method is also called a sherbet method, in which sherbet-like ice is produced and circulated. Since the material of the device is metal except for the capsule type heat storage system,
Conventional water-based heat storage materials containing an inorganic salt cannot be used due to corrosion problems, or expensive materials such as stainless steel and titanium must be used, which is difficult in terms of cost.

[0010]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. Examples 1 to 3 Erythritol was manufactured by Mitsubishi Chemical Foods Corporation, and water was pure water. Water and erythritol were blended so that the erythritol had the blending amount shown in Table 1, and completely melted with stirring at 50 ° C. 50 g of the obtained heat storage material composition
Was placed in a 100 cc glass screw bottle (SV-100, manufactured by Nidec Rika Glass Co., Ltd.), and the temperature at a height of 1 cm from the bottom of the screw bottle was measured using a thermocouple. Put the glass screw mouth bottle filled with the heat storage material composition in a temperature-controlled water tank,
The melting temperature of the heat storage material was measured. After maintaining the temperature of the water tank at −9 ° C. and completely solidifying the heat storage material compositions of Examples 1 to 3, the mixture was heated to 6 ° C. at a heating rate of 7.5 ° C./Hr, and 6 ° C.
And the melting temperature of the heat storage material composition was measured. The temperature change of the water temperature is shown in Figs.
Shown in

As shown in FIG. 1, the first embodiment (FIG. 1 (1))
From Example 2 to Example 135 (FIG. 1 (2)), 7 minutes
From 0 minutes to 150 minutes, in Example 3 (FIG. 1 (3)), the temperature did not change at −3 ° C. and melted at −3 ° C. from 70 minutes to 160 minutes.

Comparative Examples 1 and 2 The same procedures as in Example 1 were carried out except that the amounts were changed as shown in Table 1. The results are shown in FIGS. 1 (4) and (5), and the melting temperature and the like are shown in Table 1. As shown in FIG. 1, Comparative Example 1 (FIG.
(4)) appears to have melted at around 0 ° C., indicating that it does not show a clear melting point at −3 ° C. as in Examples 1 to 3. Comparative Example 2 (FIG. 1 (5)) did not show a clear melting point,
It is considered that erythritol did not solidify, probably because it was precipitated from the relationship of solubility.

[0013]

[Table 1]

[0014]

According to the present invention, a heat storage material composition having a melting point around -3 ° C can be obtained.

[Brief description of the drawings]

FIG. 1 shows melting temperature curves of Examples and Comparative Examples.

[Description of Signs] 1: Example 12 2: Example 23 3: Example 34: Comparative Example 15: Comparative Example 26: Temperature of water tank

Claims (5)

[Claims] 1. Erythritol 6-25% by weight and water 7
A heat storage material composition comprising 5 to 94% by weight and having a melting point of -5 ° C or more and less than 0 ° C. 2. The heat storage material composition according to claim 1, further comprising at least one selected from silver iodide, potassium bromate and tripotassium phosphate as a supercooling inhibitor. 3. The heat storage material composition according to claim 1, wherein the supercooling inhibitor is contained in an amount of 0.01 to 3 parts by weight based on 100 parts by weight of erythritol and water in total. 4. The heat storage material composition according to claim 1, which contains a water-insoluble water-absorbent resin or a water-soluble polymer as a thickener. 5. A thickener comprising a total of 1 erythritol and water.
The heat storage material composition according to any one of claims 1 to 4, wherein the heat storage material composition is contained in an amount of 0.1 to 5 parts by weight based on 00 parts by weight.