JPS5896997A - Heat accumulating material - Google Patents

Abstract

PURPOSE:To prevent the undercooling from occuring and increase the accumulating heat quantity per unit volume or weight by a method wherein crystal nucleus forming agent is added to a CaCl2-H2O system. CONSTITUTION:BaTiS3, BaZrS3, BaHfS3, BaVS3, BaNaS3 or BaTaS3 is added to the CaCl2-H2O system as crystal nucleus forming agent of CaCl2-H2O. Not exceeding 40 parts of crystal nucleus forming agent 10 100 parts of CaCl2-H2O system, by weight, is preferable, because the addition of too much crystal nucleus forming agent brings the decrease of accumulating heat quantity of the system as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat storage material using CaC12.6H20 as a living body.

There are known heat storage materials that utilize the sensible heat of substances and those that utilize latent heat. Compared to heat storage materials that use sensible heat, yellow heat materials that use latent heat can store more heat per unit weight or unit volume, and only a small amount is required to store the required amount of heat. Therefore, it is possible to downsize the heat storage device. Furthermore, heat storage materials that utilize latent heat can store and release heat at a constant temperature at the transition point.

Conventionally, CaC12.6H20 has attracted attention as a heat storage material because it has a large melting point of 29° C. and a latent heat of fusion of 43 cal/f, and its melt is almost neutral, has little corrosivity, and is inexpensive. However, once CaC12 is melted, it is very likely to become supercooled, and the melt may not solidify even if it is cooled to 0°C.

A supercooled state is a phenomenon in which the latent heat of fusion is not released even if the material is cooled to the freezing point, and the material is cooled below that temperature.This means that heat storage materials that utilize the latent heat of fusion are susceptible to dust in the supercooled state. This is a fatal flaw.

In the present invention, B a
T L S3, B aZ r S a, B aHf S
3, B aVS 3, B aNbS3 and B a
By adding and containing at least one crystal nucleation material selected from the compound group consisting of T a S 3, supercooling phenomenon can be prevented and a heat storage material with a large amount of heat storage per unit volume or unit weight can be created. This is what we are trying to provide.

By the way, CaC12.6H20 is CaC1250-66
% by weight and 49% by weight of H2O, and in this composition, melting and solidification occur at about 29° C. unless supercooling occurs. In this case, the latent heat of fusion is 43 cal/y.

1. A system consisting of 5% by weight of CaC1246 and 53.5% by weight of H2O becomes a homogeneous aqueous solution of CaC12 at about 28°C. When this homogeneous aqueous solution is cooled to below 28°C, unless supercooling occurs, CaC12.6)I20 begins to crystallize, and as it cools, CaC12.6H2
The ratio of 0 increases. If it is cooled to about 20℃,
Approximately 60% by weight of the total mass of this system is CaCl2-eH2
0, and the remaining 60% by weight becomes a CaC12 aqueous solution.

Therefore, CaC1246.5% by weight and H2O53.5
When the system is cooled from a temperature of 28°C or higher to 201°C, there is almost no supercooling, and if CaC12.6H2o is successfully crystallized, the amount of latent heat that can be recovered is 22°C.
cal/! It becomes l.

Furthermore, as the proportion of CaCl2H2O-based water increases, the specific heat of the heat storage material increases, and the amount of heat storage due to sensible heat increases. Tsumashi, CaC12 and horses.

By controlling the ratio of heat to heat, latent heat and sensible heat can be stored at the same time. However, sweet CaC
If a system with a low concentration of 12 is used, the characteristics of the heat storage material that utilizes latent heat will be lost. Therefore, C
CaC12-H containing 5% by weight or more of aC1246-H
It is desirable to use 2O type.

Conversely, in the CaCl2-H2O system, when the content of CaC12 is increased, CaC1250-66% by weight
In a system containing the above, even if supercooling is successfully broken, the entire system will not become CaCl2.6H20, and some CaCl2
・It will remain as 4H20. In a CaC12H2O system containing 55% by weight or more of CaC12, the amount of latent heat per unit mass is less than 22 cal/y, making it impractical. Therefore, the CaCl2-H2° system actually used is
It is desirable to contain CaC12 in a range of 55% by weight or less.

In addition, B a T iSs, Ba as a crystal nucleation material
Zr53, B aHf S 3, B aVSs, B a
l'i'bSa and B aT a Ss are Ca
In the Cl2-H2O system, CaC12-eH,,01
It is effective when added in an amount of about 0.1 part by weight to 0.00 parts by weight, and even if more than 0.0 parts by weight is added, the effect is sufficient.

However, when the heat storage material of the present invention is actually used in a heat storage device for air conditioning, etc., it is common to use 7 types out of 100 to 1000. In such cases, CaC12・6H20
Even if it is melted, it does not become a homogeneous aqueous solution, and Ca
There is a low concentration solution of C12, and below there is a precipitate of nucleating material and a liquid having a high concentration of CaC12 and nucleating material. Therefore, even if the amount of crystal nucleation material added to a homogeneous solution is much smaller than the minimum content, the crystal nucleation material does not dissolve in the CaC12 solution and has a sufficient effect.

Therefore, the minimum amount of the crystal nucleation material necessary for crystal nucleation, that is, the lower limit of the mixing amount, is determined as appropriate depending on the amount of CaC12-)o used, the shape of the container housing the heat storage material, and the usage condition. All you have to do is decide.

However, adding too much crystal nucleation material is not preferable as a heat storage material. This is because the amount of heat stored as a whole will be reduced. Therefore, in practical terms, it is desirable that the amount of the crystal nucleating agent does not exceed 40 parts by weight per 10 parts by weight of the CaC12H2O system.

The present invention will be explained in detail below.

Example 1 CaC12・6H201000y and BaTi5s
1-OF +CaCl2・6H20100oy and BaZ
r531-Oy.

CaCl2* 6H201oooy and B aHf S
s 1- Oj'.

CaCl2 ・6H20100OF and Ba■31・oy
.

CaCl2- eH,,01ooo y,! : Ba
NbS31. oy and CaCl266H20100
0f, BaTa531, Oy, each with an inner diameter of 10
C)+m++, housed in a cylindrical container with a length of 1,00 cm,
It was sealed with a stopper equipped with a thermocouple insertion tube.

Place these six types of containers in a water bath at 40°C and 1o
Heating and cooling were performed continuously between .

The six types of heat storage materials of this example showed almost no supercooling and repeatedly melted and solidified stably.

FIGS. 1 to 6 show changes in the difference between the degree of supercooling, the solidification temperature, and the temperature at which supercooling breaks when heating and cooling are repeated 100 times in succession. Figure 1 shows BaTa53,
The figure shows changes in the degree of supercooling when BaZrS3 is added, Figure 3 is BaHfS3, Figure 4 is BaVS3, Figure 5 is BaNb5s, and Figure 6 is BaTa53. be. The horizontal axis of the figure shows the number of repetitions of heating and cooling on a logarithmic scale, and the vertical axis shows the degree of supercooling.

From these figures, even if the six types of heat storage materials of this example are heated and cooled 1000 times, the degree of supercooling is 3 to 3.
It can be seen that it is stable within a temperature range of 4 degrees Celsius, and its functions are working effectively without deterioration. The latent heat of fusion of the heat storage materials of this example was 43 cal/f/, and the amount of heat storage was sufficient as a heat storage material.

Example 2 CaC12, eH20750y and B aT 1S325
0ripcac12o6H2o1ooy and BaZr5s
40f.

CaCl2 e6H20960y and BaHf53-50
F.

CaC12-eH2075oy and BaVSs 250
y.

CaCl2・6H2o100y and BaNb5s 40y
.

CaCl211 snoring (,09tsoy and B aT aS
s 50 y is the inner diameter of 1 as in Example 1.
The container was placed in a cylindrical container with a length of 100 mm and a length of 100 mm, and was sealed with a stopper equipped with a thermocouple insertion tube. These six types of containers were placed in a water bath and heated and cooled continuously between 40°C and 10°C. These six types of heat storage materials showed almost no supercooling and repeatedly melted and solidified stably.

FIGS. 7 to 12 each show how the degree of supercooling changes fp when heating and cooling are repeated 1000 times. Figure 7 shows BaTiS3, Figure 8 shows BaZr53, g
g Figure 9 ij B aHf Ss, Figure 10 B aV
Sa, Figure 11 is BaNb5 Figure 12 is BaTa
FIG. These figures show that the degree of supercooling of the heat storage material of this example remains stable within the range of 3 to 4°C even after repeated heating and cooling 1000 times, and its supercooling prevention function works effectively. I can see that it is. The latent heat of fusion of the heat storage material of this example is 32 cal when BaTiS3 is added.
/jE, 30 ca when BaZr53 is added
l/y, 40 cal when adding BaHf5s
/p, 32 cal/y when BaVSs is added.

30 cal/f when adding B aNb Ss
When 5BaTaS3 is added, the amount is 40 cal/F, and both have a sufficient amount of heat storage as a heat storage material.

Example 3 CaC12-eH201000y, BaTiS31
, OF, and BaVSs 1-OF were placed in a cylindrical container with an inner diameter of 100 mm and a length of 100 mm, and the container was sealed with a stopper equipped with a thermocouple insertion tube. Put the container in a water bath for 40 minutes.
Heating and cooling were performed continuously between n and 10°C. This heat storage material rarely showed supercooling and repeatedly melted and solidified stably.

FIG. 13 shows how the degree of supercooling changes when heating and cooling are repeated 100 times in succession. As shown in this figure, even if the heat storage material of this example is heated and cooled 100 times, the degree of supercooling remains stable in the range of 3 to 4 degrees Celsius, and its supercooling prevention function does not deteriorate and works effectively. I can see that you are doing it. The latent heat of fusion of the heat storage material of this example is 43 cal/7, and has a sufficient amount of heat storage as a heat storage material.

Comparative example CaCl2・6H2o1000y with inner diameter 1001rr1
It was placed in a cylindrical container with n1 length of 100 Mn and sealed with a stopper equipped with a thermocouple insertion tube. Place the container in a water bath and melt at 40°C. IC)C'! It was cooled down.

The melt does not solidify even when its freezing point reaches 29°C, and
It did not solidify even after cooling at 0'C4.

From this, CaC12-H2 without adding crystal nucleating agent
It is clear that the o composition is unsuitable as a heat storage material.

As shown in the examples above, the heat storage material of the present invention is CaC
BaTiSa, BaHf53, BaH as a CaC12-H2o crystal nucleating material in the l2-H2O system.
f5s, BaVSs.

Since it is a metal product that does not contain B aNa S a or B a Ta S3, stable i-heat and regeneration can be performed at low cost.

As shown in the examples, the same effect can be obtained even if the crystal nucleation materials are used alone or in combination.

[Brief explanation of drawings]

FIGS. 1 to 13 show 1o of heat storage materials according to embodiments of the present invention.
It shows how the degree of supercooling changes when heating and cooling are repeated Oo times. Name of agent: Patent attorney Toshio Nakao (1st person)
figure! Blue sum Ln number (@) ゛ 2nd illustration phantom 1t, mi beast (Zeng) 3rd @ Fig. 4 8 recruitment ξ Number of strokes (before the seventh fl!

Claims (1)

[Claims] (In the system consisting of 11CaCl2 and town ρ, B a T
iS s, B a Z r S s, B a Hf S
s, BaVS 3, BaNb Sa, and Ba
A heat storage material characterized in that it contains at least one crystal nucleation material selected from the group of compounds consisting of Ta53. (2JCa In a system consisting of C12 and H2O, C
The heat storage material according to claim 1, characterized in that aCl2 is contained in an amount of 46.5 to 55% by weight. (3) The heat storage material according to claim 1, characterized in that the amount of the crystal nucleating agent added to 100 parts by weight of the system consisting of C&C12 and H2O does not exceed 40 parts by weight.