JPS59102977A - Heat accumulating material - Google Patents

Abstract

PURPOSE:To provide a heat accumulating material capable of keeping the initial heat accumulation capacity after repeated melting and freezing cycle, by adding sodium oleate, etc. to sodium sulfate decahydrate and an olefinic carboxylic acid having active C-C double bond and used as a gelling agent. CONSTITUTION:The objective heat accumulating material contains (A) sodium sulfate decahydrate (or its eutectic mixture) as a main component, (B) a homopolymer or copolymer of an olefinic carboxylic acid having active C-C bond [preferably (meth)acrylic acid], an alkali metal salt or ammonium salt of said carboxylic acid (preferably a copolymer of said carboxylic acid and a polyalkenyl polyether of a polyhydric alcohol) as a gelling agent, and (C) lithium oleate, sodium oleate or potassium oleate. The amount of the component (C) is preferably 0.01-0.5pts.wt. per 100pts.wt. of the component (A). USE:Room heating of a passive solar house, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat storage material used for heating passive solar houses and the like.

Conventional configuration and its problems From the perspective of cooling and heating using solar heat or waste heat, and reducing the load on air conditioners for the purpose of alleviating power peaks,
The need for heat storage is increasing. A heat storage method that utilizes the latent heat of a substance has the advantage of having a relatively high heat storage density and being able to transfer a large amount of heat in and out with a small temperature difference. - Thermal materials for blade replacement are required to be inexpensive, available in large quantities, non-flammable, non-corrosive, and non-flammable.

Sodium sulfate 10 as a fee for these purposes.
Examples include water salts and eutectics thereof. 1-lium sulfate 1
0 hydrate salt has a melting point at 32 °C and 60 cna/y-
It has a latent heat of Also, sodium sulfate decahydrate d: It is possible to change its melting point by creating a eutectic,
For example, 1 mole of sodium sulfate 1Q hydrate has 1 mole of potassium chloride.
The melting point can be lowered by about 4°Ct in a molar mixed eutectic.

Generally, there are two problems when using a hydrate as a heat storage material. One of them is the so-called supercooling phenomenon in which the material does not solidify even if the temperature drops below the freezing point during cooling. In the case of sodium sulfate decahydrate and its eutectic, US Pat. No. 2,667,664 discloses that the problem can be solved by adding sodium tetraborate decahydrate (borax) as a nucleating material. There is. Other problems are sodium sulfate 1
The 0-hydrate salt and its eutectic exhibit anharmonic melting. That is, since the solubility of 1-lium sulfate anhydride is low when it melts at the melting point, it does not completely dissolve in the crystallization water, and a portion remains in the solution, and because of its high density, it precipitates. When such a mixture is cooled and solidified in a static state, the dissolved sodium sulfate or its eutectic forms a decahydrate and returns to the state before melting, but only the surface of the precipitated anhydrous sodium sulfate remains. It becomes decahydrate, and some of it remains on anhydrous sodium sulfate. Therefore, when such a system is subjected to repeated cycles of heat storage and heat release of melting and solidification, the amount of heat storage decreases because the remaining sulfuric acid anhydride (l-1) ram does not participate in phase transformation. As a solution to this problem, a method has been proposed that prevents precipitation of anhydrous sodium sulfate and uniformly disperses and maintains it in a solution. Specific methods include liquid solution, wood pulp, methylcellulose, and starch.

Organic alginate, polyacrylic acid (Ionic bond cross-linked product with polyvalent metal ions)
The solution is thickened with an organic polymer compound 1 such as silica gel, diatomaceous earth, finely powdered silica, or an inorganic thickening agent such as acpal guide type clay (US Pat. No. 3,986,969). Attempts have been made to create a so-called gel state.

However, even when precipitation of anhydrous 1-IJ sulfate is prevented by such a method, crystal particles of anhydrous 1-IJ sulfate grow due to repeated cycles of melting and solidification, and only the surface of the particles grows during solidification. A hydrate is formed, and the center of the particle remains anhydrous. As a result, even in systems that prevent precipitation of anhydride due to gelation, the amount of heat storage decreases with cycles, which is a major obstacle to practical application.

Purpose of the Invention In view of the above circumstances, the present invention aims to suppress the growth of crystal grains due to repeated cycles of melting and solidification of sulfuric acid (sulfuric acid), lithium decahydrate and its eutectic, and to prevent a decrease in heat storage amount. This is what was done.

Structure of the Invention The heat storage device of the present invention is an olefinic carboxylic acid moiety having a carbon-carbon double bond active as a gelling agent, or an alkali of said carboxylic acid, which is mainly composed of sodium sulfate decahydrate or its eutectic. It is constructed by adding at least one of sodium oleate, lithium oleate, and potassium oleate to a system containing a homopolymer or copolymer of a metal salt or ammonium salt.

In addition to the above substances, the heat storage material contains 2 to 6 parts by weight of borax (NIL2B407/10H20) as an anti-supercooling agent, but the addition of an anti-supercooling agent such as borax does not essentially limit the structure of the present invention. do not have.

DESCRIPTION OF EXAMPLES The gelling agent used in the preparation of the heat storage material according to the present invention has the trade name [HIVIS WAKO-1041゜"CARBOP/
l/934J, g Aqua Keep 4SJ.

“Sunwet IM300J,” “Aron A209”
.

[Rheosic 250HJ, r Shunron PW110
'', all of which are homopolymers or copolymers of olefinic carboxylic acids having active carbon-carbon double bonds, or alkali metal salts or ammonium salts of the carboxylic acids.

A typical example of a homopolymer is “Aqua Keep 4SJ”.
It is obtained by polymerizing a carboxylic acid partially neutralized with alkali metal ions or ammonium salts, and the details are disclosed in JP-A-56-26909. Representative example of copolymer N: l Hibisfuco-104
” and “Sunwet IMs○O”, the former being a polyalkenyl polyether of acrylic acid and polyhydric alcohol,
The latter is a copolymer of at least one kind of acrylic acid or methacrylic acid, starch, and cellulose.
It is disclosed in Publication No. 199.

Among the above-mentioned commercial products, "Hibiswako-104", [Carbobo] v934J, and "Shunron PW110" are obtained as carboxylic acid polymers, so in the process of making the heat storage moon, the threads kneaded with the gelling agent and water are used. It is preferable to use it after neutralizing it with NaOH etc. 1 other than the above-mentioned gelling agent
Aqua Keep 4S”, “Sun Wet IM300”, [
Since Rheosic 250HJ and Aron A2oPj are obtained as polymers of alkali metal salts or ammonium salts of carboxylic acids, it is not necessary to perform the above-mentioned neutralization treatment when preparing the heat storage material.

In the following examples, the seven gelling agents and alkali metal oleate were mixed with sodium sulfate decahydrate (Na2SOa
The heat storage characteristics when applied to 10H20, melting point ~32°C) and its eutectic, in particular the rate of decrease in heat storage amount due to repeated melting/solidification cycles, will be explained.

<Example 1>Na2-8O4"'44 parts by weight H2056 Na2B40710H20 (borax) 3 Hibiswako-1041,6 NaOH0,66 1-lium oleate゜0.0
5.0.1', 0.2.0.5. Seven types of samples of 1.0 were prepared.

These samples were repeatedly heated and cooled at 40° C. and -3° C., and their heat storage properties were measured. Table 1 shows the change in heat storage amount of each sample before and after the cycle.

Table 1 Initial heat storage amount s 2 , 4 ayp, / y- of samples to which sodium oleate was not added was 150
After the cycle, the heat storage amount decreased by 8.4% to 48-07/no, and when sodium oleate was added to 0.0%.
In the sample to which 01 parts by weight was added, the rate of decrease in the amount of heat storage remained at 4.4% even after 160 cycles, and the effect of adding 1-lium oleate was clearly recognized. As the amount added increased, the rate of decrease in the amount of heat storage reached the level of 2 and showed a tendency to increase again.

For a sample with an additive amount of 1.0 parts by weight, the rate of decrease in heat storage amount was 7
・Although it was slightly smaller than the sample with no additives, the initial heat storage amount was 45 ayE/y- or less, and for practical purposes, it is desirable that the amount added be 0.5 parts by weight or less.

<Example 2> Na2SO437, 5 parts by weight H204, 7 Mail 7.7NHZC17
,1 NIL2 B407 ・10H203,4 Hibinuwako-IQ4 2.3NaOH0,93 Sodium oleate
Three types of samples of 05 were prepared. The sample is Na25O+・1
0H20 (melting point 32℃) 1 mole of NaCl 1゜NH4Cl
are added at a rate of 0.5 mole each to melting point ~1
It is a 3°C eutectic. Similar to Example 1, the heating/cooling cycle was repeated to measure the change in heat storage amount. Table 2 shows the results.
Shown below. In a sample containing 0.01 part by weight of mono-lithium oleate, the rate of decrease in heat storage after 6Q cycles was 1.
The ratio was 8, which was clearly lower than the ratio 6 when no additives were used.

Table 2 <Example 3> Na2304 23.1 parts by weight Na2
Go517.4 H2O59,2 Na2B407・10H203 Hibiswako-1041,6 parts by weight NaOH0,66 Sothorium oleate
Six types of samples were created: 55.0.1.0.145.0.19. The sample is a eutectic of Na2SO4,10H201-E-nyl and Na2O0s.10H201 mole, and has a melting point of ~24°C. Similar to Example 1, the heating/cooling cycle was repeated to measure the change in heat storage amount. As shown in Table 3, the rate of decrease in heat storage amount after 39 cycles was 13.9% for the sample without sodium oleate, but 0.0%.
When 1 part by weight is added, the reduction rate is 8. When 0.055 parts by weight was added, a remarkable effect of 0.9 was observed.

Below is a blank space 3 <Example 4> In Example 3, 1 carbobo/l/934 J was used for the filling of ``1 Hibiswako-1o4'', and a sample without the addition of thorium oleate and a sample with 0.03 parts by weight of sodium oleate were prepared. Created. After 60 cycles, the rate of decrease in heat storage amount was 14.5% for the sample without the addition of 1-lium oleate, and 3.5% for the sample with 0.03 parts by weight added. It shows a clear decline compared to the Q section.

<Example 5> In Example 3, ``Shunron PW-11oJ'' was used instead of ``Hibisfuco-104'' to prepare a sample without the addition of sodium oleate and a sample with 03 parts by weight of sodium oleate added. 60 cycles. The rate of decrease in the amount of heat storage was 11.4% for the former and 0.9% for the latter, showing a remarkable difference.

<Example 6> In Example 3, 2 parts by weight of Aqua Keep 4SJ was used in Hibisfuco-104J and NaOH, and samples were prepared in which sodium oleate was not added and 0.03 part by weight was added. The rate of decrease in heat storage amount after 60 cycles was 13.1 in the former and 4.9 in the latter, showing a clear decrease.

<Example 7> In Example 3, 2.7 parts by weight of [Sun Ueno IM300 instead of Hibisfuco-104-1 and NaOH] were used, and a sample without the addition of sodium oleate and a sample with 0.03 parts by weight of sodium oleate were prepared. Created.

After 60 cycles, the rate of decrease in heat storage amount was 9.1% for the former and 1.8% for the latter, showing a clear decrease.

<Example 8> In Example 3, 2.7 parts by weight of "Aron A20P" was used instead of "1 Hibiswako-1o4" and NaOH, and a sample without and a sample with 0.03 parts by weight of thorium oleate were prepared. Created. After 60 cycles, the rate of decrease in heat storage amount was 6.8% for the former and 5.1% for the latter, showing a slight decrease.

<Example 9> In Example 3, 2.7 parts by weight of [Rheozinc 250H] was used instead of "Hibiswako-104" and NaOH, and 0.03 parts by weight was added to the sample without addition of I-lium oleate. I created a try-on. The rate of decrease in heat storage after 60 cycles was 9.1% for the former and 6.1% for the latter, showing a clear decrease.

<Example 10> In Example 1, lithium oleate was used instead of thorium oleate, and a trial fitting with X=0.05 was created.

The reduction rate of heat storage amount after 150 cycles is 3.7%,
This was clearly lower than 8.4 inches without the addition of lithium oleate.

<Example 11> A sample was prepared in Example 10 using potassium oleate instead of lithium oleate. The rate of decrease in the amount of heat storage after 160 cycles was 2.9 times, which clearly decreased compared to the case without additives.
The main component is sodium sulfate decahydrate or its eutectic, and the product names are [Hibis Wako 104J, "Carbo Ball 934", [Aqua Keep 4S-1, and [Zanwet I].
M3ooJ, [Aron A20PJ, [Rheosic 250]
HJ, “Shun III’:y P W 110 J
The amount of heat stored in a heat storage material gelled with a polymer of an olefinic carboxylic acid having an active carbon-carbon double bond, or an alkali metal salt or an ammonium salt of the carboxylic acid, as represented by Te, is determined by a cycle of 9 cycles of melting and solidification. The decrease is
At least one of sodium oleate, lithium oleate, and potassium oleate is added to 100 parts by weight of sodium sulfate decahydrate or its eutectic, and 0.01 parts by weight or more and 0.6 parts by weight or less. suppressed.

The polymer may contain an olefinic carboxylic acid having an active carbon-carbon double bond or an alkali metal salt or ammonium salt of the carboxylic acid, and the substances used to form the copolymer are as described in Examples. So, we talked about polyalkenyl polyethers of polyhydric alcohols, starch, and cellulose, but other than these, such as acrylate)
) Reami l-”.

A similar effect can be obtained with inbutylene. Furthermore, although acrylic acid and tutaacrylic acid have been described as the carboxylic acids, other acids such as maleic anhydride and ethacrylic acid may also be used, and copolymers of two or more of the carboxylic acids may also be included.

In the above example, sulfuric acid sulfate/lium 10 hydrate, sulfuric acid 1/1
- Although the eutectic of lithium monohydrate, ammonium chloride, and thorium chloride, and the eutectic of monolithium sulfate decahydrate and sodium carbonate decahydrate, the effect of the present invention is based on sulfuric acid) This phenomenon is also observed in other eutectic products containing monium 1o hydrate, and the scope of application of the present invention is not limited to the above-mentioned eutectic products. As for the amount of gelling agent added, it is sufficient that it is in the range of 1 part by weight to 6 parts by weight per 100 parts by weight of sodium 1-lium sulfate decahydrate or its eutectic, as is usually used. Furthermore, borax added as an anti-supercooling agent does not depart from the spirit of the present invention.

Effects of the Invention As described above, the present invention provides an olefinic carboxylic acid containing sodium sulfate decahydrate and its eutectic as a main component and having a carbon-carbon double bond that is active as a gelling agent. 1-lium oleate for heat storage materials containing homopolymers or copolymers of alkali metal salts or ammonium salts.

Adding at least one of lithium oleate and potassium oleate, it has the advantage of suppressing the decrease in heat storage due to repeated melting and solidification.
, a practical heat storage material with less decrease in heat storage amount can be obtained.

Claims (5)

[Claims] (1) A homopolymer of an olefinic carboxylic acid or an alkali metal salt or ammonium salt of the carboxylic acid, which has sodium sulfate decahydrate or its eutectic as a main component and has a carbon-carbon double bond that is active as a gelling agent. A heat storage material comprising a copolymer and further comprising at least one of lithium oleate, sodium oleate, and potassium oleate. (2) Sodium sulfate decahydrate or its eutectic 10
Claim 1, characterized in that at least one of lithium oleate, sodium oleate, and potassium oleate is contained in a range of 0.01 part by weight or more and 0.5 part by weight or less per 0 part by weight. Heat storage interest stated in section. (3) The heat storage battery according to claim 1, paragraph 4, wherein the olefinic carboxylic acid having an active carbon-carbon double bond is acrylic acid or methacrylic acid. (4) The heat storage material according to claim 1, wherein the copolymer is a polyalkenyl polyether of an olefinic carboxylic acid and a polyhydric alcohol having an active carbon-carbon double bond. (5) The heat storage according to claim 1, wherein the copolymer is composed of at least one of olefin 1 /'J /lzhonQl starch and cellulose having an active carbon-carbon double bond. Abduction.