JPS58180580A - Heat storage material - Google Patents

Abstract

PURPOSE:To provide a latent heat storage material which is prevented from supercooling in freezing, prepared by adding at least one nucleator selected from among activated carbon, Na2B4O7, Na3AlF6 and Sr(OH)2.8H2O, to NiNO3. 6H2O. CONSTITUTION:The heat storage material consists of NiNO3.6H2O and at least one nucleator selected from among activated carbon, Na2B4O7, Na3AlF6 and Sr(OH)2.8H2O. NiNO3.6H2O has a fusing point of about 54 deg.C and a latent heat capacity of 31Cal/deg and is suitable as heat storage material for room heating and hot water supply at 50-60 deg.C, but it has a demerit in that the difference between the fusing temperature and the freezing starting temperature (DELTATsc) is too large. The addition of the nucleator reduces DELTATsc to about a half to one- third.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat storage material. More specifically, the present invention relates to a latent heat type heat storage material that prevents supercooling during solidification.

Water and crushed stone have traditionally been used as heat storage materials. These exhibit a sensible heat storage action that utilizes the specific heat of the substance, and when viewed from the heat storage density, l tut/d e
g or less, which is small. Therefore, as long as these heat storage materials are used, the heat storage device needs to be quite large, and as the heat is released, the humidity level of the stored heat gradually decreases, making it difficult to obtain stable thermal energy.

In recent years, on the other hand, research on latent heat storage using the melting and solidification of materials has been actively conducted.

Latent heat storage utilizes the phase change of materials, especially the absorption and release of heat during melting and solidification, and has a heat storage density of several 10
It has the advantage of being able to obtain thermal energy with a high cm/dθg and constant humidity, and that the heat storage device can be made more compact.

A wide variety of heat storage materials are used, but the types are quite limited when used for heating purposes such as space heating and hot water supply. In particular, when the temperature level is 50 to 60°C, currently considered heat storage materials are limited to organic substances and inorganic hydrated salts.

A typical example of the organic latent heat type heat storage material is paraffin. Such organic substances are hardly edible or toxic, and the safety of the materials is guaranteed. Also,
There are also 11 cycles of melting and solidification. However,
The amount of latent heat is relatively small at 10 to 3 Qatl/deg.
Furthermore, since the thermal conductivity of the material itself is low, there is a problem in using it as a heat storage material.

On the other hand, inorganic hydrated salts generally have a self-heat amount of 30 to 60 m/d.
It has a relatively large eg and a high thermal conductivity compared to organic materials, so it is considered promising as a heat storage material.

However, inorganic hydrated salts have the disadvantage that they undergo significant supercooling during solidification and cannot effectively obtain thermal energy at the desired temperature level, which essentially undermines the advantages of latent heat storage materials. This is a problem that must be avoided at all costs.

In order to prevent such supercooling of the heat storage material, it is being considered to add a nucleating agent to the heat storage material as a nucleating material (for example, JP-A-55-120,686;
-126,980 publication, 51-70.193 publication and J, appl, Ohem, Biotech
%no1. 28, pp. 761-764, 1978, etc.). Regarding the relationship between the heat storage material and the nucleating agent,
It is said that those whose crystal structures are similar to each other are effective,
Alternatively, there are many theories as to the cause of this, such as those with similar interlattice distances being effective, but the structural relationship between the two is generally unknown. Therefore, many trials are required to find an effective combination.

The inventor of the heather has found that the material has favorable properties such as a melting humidity of approximately 54°C and a self-heat amount of 31 cal/a e g as a heat storage material for heating purposes such as space heating and hot water supply at 50 to 60°C. , degree of supercooling (ΔTsc:
As a result of extensive research in search of a nucleating agent that would stop the supercooling of ILV91 for the nitrate nickel b hydrate N1(No,)2.6H20, which has the drawback of having a large We have found that compounds of the same class or mixtures thereof are effective for such purposes.

Therefore, the present invention relates to a latent heat type heat storage material, which includes nickel nitrate hexahydrate, an active layer as a nucleating agent, sodium boroshima, cryolite, and strontium 8 hydroxide.
One or more hydrates are added.

The degree of supercooling is indicated by the difference ΔTsc between the melting temperature A and the solidification start humidity B of the first material, as shown in the graph showing the temperature change of the material with respect to the elapsed time when the temperature is lowered. By adding these nucleating agents to the hexahydrated proboscis, the f1 value of ΔTac can be reduced to approximately 1 ``ki'' compared to the case without the addition.

Live charcoal used as a stimulant, Ho-o-nato 1' Lamb N
a2 E a O7, quartzite Na, AfF6 or pore-formed strontium octahydrate vIJSr(OH)2.8
Among H20, quartzite is effective as an anti-supercooling agent for alkali metal nitrate hydrates such as lithium nitrate or heat storage materials whose main ingredients are quartzite, as disclosed in JP-A-51-128.051. Although it is described in the publication, the same publication also states that strontium hydroxide 8 water 4=<
It is also stated that +4a does not exhibit any d cooling prevention effect.

Nitrate chive gel hexahydrate used in the present invention and lithium nitrate trihydrate (, tl) used in the present invention are completely different in 4L-J properties, and are latent heat type heat storage. The use of the material is determined by its physical properties.In fact, the heat storage material according to the present invention is used for heating purposes, and the alkali metal nitrate hydrate heat storage material is used for cooling purposes (Japanese Patent Application Laid-Open No. 126-1989,
No. 80) have been used for a long time, and the effects of the heat storage materials naturally vary depending on these heat storage materials.

Next, the present invention will be described in detail with reference to examples.

Example 1 Nucleating agents of 1% and 1% were added to nickel nitrate hexahydrate, respectively, and their ΔTsc values were measured according to the following method.

Contains 10 g of tI11 hexahydrate 20
Pour into a 1nl volume 14 and add powdered nucleating agent 0.1 to it.
Add g and seal tightly. This was left in a constant temperature bath at 90° C. for 1 hour to completely melt. Next, the container containing the molten sample mixture was left in water at 10°C, and JA
Cool while stirring with a stirrer. The sample mixture is supercooled to a certain temperature, leading to solidification.

The temperature change during this temperature drop was measured with a thermocouple, and the degree of supercooling ΔTsc was investigated. The results obtained are shown in Table 1 (■).

Table 1 None 16 Activated carbon 8 Sodium borate 8 Cryolite
9 Hydrogenated strontium octahydrate 5 Example 2 Various proportions of activated carbon were added to nickel nitrate hexahydrate using the method described in Example 1 to supercool them. The degree ΔTsc was investigated. The result is,
It is shown in Table 2 below.

Table 2 16 Q, l 11 310 1.08 5.07 006 A similar tendency was observed when sodium borate, ice crystal 6, or strontium hydroxide octahydrate was used as the first abrasion. It was seen.

From these results, it can be seen that in combinations that are effective in preventing supercooling, the greater the proportion of the nucleating agent added, the more pronounced the effect becomes. However, adding an excessive amount of the nucleating agent is meaningless because it lowers the latent heat of the heat storage material. For example, the amount of latent heat of a heat storage material to which 10 parts by weight of activated carbon is added is only 28 m/aeg as measured by a differential scanning calorimeter (DSO). Therefore, with regard to the amount of latent heat, it is preferable that the amount of the nucleating agent added is small.

In this way, the supercooling prevention effect of the nucleating agent and the amount of latent heat of the heat storage material to which it is added have contradictory effects as the amount of the nucleating agent added increases, so it is important to consider the mode of using the heat storage material. Therefore, the amount of addition is limited. For example, the heat storage agent containing activated carbon has a latent heat amount of 30 aJt/
In a usage mode where a is 8g or more and ΔTac or IQ deg is required, the amount of activated carbon added is preferably in the range of about 0.3 to 5% by weight.

[Brief explanation of the drawing]

The drawing is a graph showing a general temperature change of the heat storage material with respect to the elapsed time when the temperature falls. Here, ΔTsc is the melting temperature A of the material and the solidification start temperature B
It shows the difference between Representative Patent Attorney Yoshi 1) Yufu Proceedings Amendment a (Voluntary) l Indication of references 1982 Patent Application No. 64947 2 Name of invention Heat storage material 3 Person making amendment Relationship with case Patent applicant name Name (438) Japan Oil Seal Industry Co., Ltd. 4th Director Address 50 Ato Building, 1-2-7 Shiba Daimon, Minato-ku, Tokyo
Detailed Description of the Invention in Specification No. 1 - Contents of 6 oil stops + 1) "1"/ in the 1st negative 17th line is 11'/g,
Correct to deg J. sgJ

Claims (1)

[Claims] Nitnal mononitrate hexahydrate, activated carbon, sodium borate, cryolite, and strontium hydroxide as a nucleating agent.
A latent heat type heat storage material made by adding one type of 8 permanent compounds or 211 or more. 2. A latent heat type heat storage material according to claim 1, which is used for heating purposes.