JPS5821942B2 - Heat storage agent composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides calcium chloride hexahydrate (CaCI2.6H2
0) or disodium hydrogen phosphate dodecahydrate (Na2) f
This invention relates to a heat storage agent composition mainly composed of PO4.12H20).

Generally, methods for storing heat include methods that utilize the sensible heat of substances and methods that utilize latent heat.

A typical example of a method that uses sensible heat is water.

Water has a large specific heat, is easy to handle, and above all, is extremely cheap.

Outside of Mercury, gravel, crushed stone, and bricks are used.

However, if an attempt is made to store heat using sensible heat, the capacity and weight of the heat storage device will become considerably large.

Another disadvantage is that the temperature of the heat storage agent itself decreases in proportion to the release of heat.

On the other hand, examples of methods that utilize latent heat include methods that use inorganic hydrated salts and organic crystalline substances.

In principle, this method utilizes phase change phenomena such as melting that occur at a constant temperature, and the temperature drop of the heat storage agent due to heat release is small, and the latent heat of phase change such as melting is generally large, making it compact. can store heat.

The present invention utilizes a technology for storing heat by utilizing the latent heat of fusion of this inorganic water salt, in particular calcium chloride hexahydrate and disodium hydrogen phosphate dodecahydrate, which have melting points slightly higher than room temperature, and uses these as a heat storage agent. This relates to technology for modifying materials to make them suitable for use.

Calcium chloride hexahydrate is originally known as an inexpensive heat storage material, but it has two crystal structures with different latent heats of fusion and is corrosive.
It has the disadvantage that it exhibits a noticeable supercooling phenomenon.

When the temperature of calcium chloride hexahydrate is gradually lowered from its molten state, it does not solidify (crystallize) or release heat even after the original phase change temperature (29°C), which is the supercooling phenomenon. This causes a practical inconvenience in that even if heat is stored in the salt, the heat cannot be extracted at a predetermined temperature.

Therefore, in order to use calcium chloride hexahydrate as a heat storage agent, it is important to suppress this supercooling phenomenon.

IJium dodecahydrate has a heat of fusion of 63
Cal/g, density 15:11/! Therefore, the heat of fusion per unit volume is 97 cal lcr&, which is one of the largest among inorganic water salts, and it is a very inexpensive heat storage agent that can store heat more compactly.

However, when the temperature of disodium hydrogen phosphate dodecahydrate is gradually lowered from the molten state, the original phase change temperature (34°C)
It has the disadvantage of exhibiting a supercooling phenomenon in which it does not solidify (crystallize) and does not dissipate heat even after the temperature has passed.

This supercooling phenomenon causes a practical inconvenience in that even if heat is once stored in the heat storage agent, the heat cannot be taken out at a predetermined temperature.

Therefore, in order to use disodium hydrogen phosphate dodecahydrate as a heat storage agent, it is important to suppress this supercooling phenomenon.

The present invention prevents the supercooling phenomenon of the above-mentioned calcium chloride hexahydrate and disodium hydrogen phosphate dodecahydrate, and provides a heat storage agent composition that is inexpensive, has stable heat absorption and radiation performance, and has a high heat storage density. The present inventors aimed to suppress the supercooling phenomenon of calcium chloride hexahydrate and disodium hydrogen phosphate dodecahydrate,
Calcium chloride hexahydrate and disodium hydrogen phosphate 12
As a result of intensive research into nucleating agents that promote the formation of crystal nuclei during the heat dissipation crystallization process of aqueous salts, we have discovered a nucleating agent that is effective against calcium chloride hexahydrate and disodium hydrogen phosphate dodecahydrate. This discovery led to the completion of the present invention.

That is, the gist of the present invention resides in a heat storage agent composition in which copper powder and a thickener are added to calcium chloride hexahydrate or disodium hydrogen phosphate dodecahydrate.

The surface of the copper powder comes into contact with calcium chloride hexahydrate or disodium hydrogen phosphate dodecahydrate and effectively acts as a nucleating agent.

Therefore, as for the copper powder used in the present invention, the surface of the copper powder with rough edges and fine edges is in efficient contact with calcium chloride hexahydrate or disodium hydrogen phosphate decahydrate, and the calcium chloride hexahydrate or phosphate This is preferable because the formation of crystal nuclei of disodium oxyhydrogen dodecahydrate is promoted.

The preferred particle size of the copper powder used in the present invention is 1
00 microns or less, more preferably 30 microns or less.

The amount of copper powder used in the present invention depends on the particle size of the copper powder.

In other words, if the particle size of the copper powder is small, the amount added may be small;
The amount added increases as the particle size increases.

The preferred amount of copper powder used in the present invention is as follows:
As mentioned above, depending on the particle size, calcium chloride 6
The amount ranges from 0.001 parts by weight to 20 parts by weight per 100 parts by weight of hydrate or disodium hydrogen phosphate decahydrate;
More preferably, it is in the range of 0.1 parts by weight to 10 parts by weight.

As described above, the present invention provides a heat storage agent that does not exhibit a supercooling phenomenon by adding copper powder to calcium chloride hexahydrate or disodium hydrogen phosphate dodecahydrate;
Of course, even if copper powder is added to a mixture of calcium chloride hexahydrate and disodium hydrogen phosphate dodecahydrate, no supercooling phenomenon will occur.

In addition, depending on the temperature to which the heat storage agent is exposed, additional measures may be taken to prevent precipitation or aggregation of calcium chloride tetrahydrate or dihydrate, disodium hydrogen phosphate heptahydrate or dihydrate, or copper powder during melting. Add a thickener such as carboxymethyl cellulose or fine silica powder.

Additionally, additives such as a solidification heat release temperature regulator may be added as appropriate.

Therefore, when the heat storage agent composition of the present invention is heated normally,
First, heat is accumulated as sensible heat in the solid phase state, and then when the solid phase changes from the liquid phase, a large amount of heat is accumulated as the latent heat of melting, and when the phase completely changes to the liquid phase, heat is further accumulated as sensible heat. It accumulates.

When releasing heat, sensible heat is normally released from the high-temperature liquid phase state to the solidification temperature, and at the solidification temperature, the heat that was previously accumulated as latent heat of melting at that temperature is released without causing supercooling phenomenon. is released as latent heat of solidification (crystallization) over a long period of time, and when it completely changes to a solid phase, it releases heat as sensible heat while further lowering the temperature of the heat storage agent itself.

As mentioned above, the heat storage agent composition of the present invention is made by adding copper powder and a thickener to calcium chloride hexahydrate or disodium hydrogen phosphate dodecahydrate, so it is inexpensive and does not cause supercooling. It has extremely stable heat absorption and radiation performance, and has a high heat storage density.

Further, since the heat storage agent composition of the present invention contains copper powder having good thermal conductivity, it has good heat conductivity and can easily transfer heat in and out.

Since the heat storage agent composition of the present invention has a melting point slightly higher than room temperature, it can be used in residential equipment such as floor heating and wall heating, and various other heat storage applications by combining it with solar heat or other heat sources. It can be used for.

Examples of the present invention will be shown below.

Example 1 To 100 parts by weight of calcium chloride hexahydrate, 3 parts by weight of finely powdered silica (Aerosil +380; manufactured by Nippon Aerosil ■) was added and stirred and mixed to prepare a urine sample.

Copper powder (median diameter 12 microns; measured by sedimentation method) was added to this urine sample 30F. The mixture was stirred and mixed into a test tube with an inner diameter of 1371 m and a length of 180 m, a thermocouple was inserted into the center of the tube, and the upper end was sealed with a rubber stopper.

Then, this test tube was immersed in a constant temperature water bath at 45°C and sufficiently heated until the inside was melted and the temperature reached 45°C.

Next, this test tube was immersed in a constant temperature water bath at 15° C. to radiate heat, and the temperature change of the heat storage agent composition in the test tube was measured.

The heat release curve becomes as shown in 1 in FIG. 1, and this heat storage agent composition does not cause supercooling.

It was confirmed that solidification heat was dissipated for a long time at 29°C.

Comparative Example 1 Urine sample 3 prepared in Example 1 without the addition of copper powder
The heat dissipation behavior at 0 g was measured in exactly the same manner as in Example 1.

The heat release curve was as shown in 2 in Figure 1, confirming that this urine sample was supercooled and hardly solidified and did not release heat.

Example 2 Finely powdered silica (Aerosil≠380; Nippon Aerosil■
A urine sample was prepared by adding 3 parts by weight of the product (manufactured by Alumni Co., Ltd.) and stirring and mixing.

This urine sample 30. ! Add 0.3 mm of copper powder (median diameter: 12 microns; measured by sedimentation method) to i', stir and mix, and place the mixture in a test tube with an inner diameter of 18 mm and a length of isom, and a thermocouple is attached to the center of the tube. It was inserted and the top end was sealed with a rubber stopper.

Then, this test tube was immersed in a constant temperature water bath at 60°C and sufficiently heated until the inside was melted and the temperature reached 60°C.

Next, this test tube was immersed in a constant temperature water bath at 15° C. to radiate heat, and the temperature change of the heat storage agent composition in the test tube was measured.

The heat dissipation curve was as shown in 1 in FIG. 2, and it was confirmed that this heat storage agent composition solidified and dissipated heat for a long time at 35° C. without causing supercooling.

Comparative Example 2 Urine sample 3 prepared in Example 2 without the addition of copper powder
(The heat dissipation behavior of 1 was measured in exactly the same manner as in Example 2.

The heat release curve was as shown in 2 in Figure 2, confirming that this urine sample was supercooled and hardly solidified and did not release heat.

[Brief explanation of drawings]

Fig. 1 is a graph showing the heat dissipation behavior of the heat storage agent composition of the present invention using calcium chloride hexahydrate and a conventional heat storage agent composition to which no copper powder is added, and Fig. 2 is a graph showing the heat dissipation behavior of the heat storage agent composition of the present invention using calcium chloride hexahydrate. 1 is a graph showing the heat dissipation behavior of a heat storage agent composition of the present invention using IJum dodecahydrate and a conventional heat storage agent composition to which no copper powder is added.

Claims (1)

[Scope of Claims] 1. A heat storage agent composition prepared by adding copper powder and a thickener to calcium chloride hexahydrate or disodium hydrogen phosphate dodecahydrate. 2. The heat storage agent composition according to claim 1, wherein the copper powder has a particle size of 100 microns or less. 3. Copper powder is added in the range of o, ooi parts by weight to 20 parts by weight to 100 parts by weight of calcium chloride hexahydrate or disodium hydrogen phosphate decahydrate. The heat storage agent composition according to item 2.