JPS60163988A

JPS60163988A - Thermal energy storage material

Info

Publication number: JPS60163988A
Application number: JP1863284A
Authority: JP
Inventors: Fumiko Yokoya; 横谷　文子; Takahiro Wada; 隆博和田; Yoshihiro Matsuo; 嘉浩松尾; Hiroshi Komeno; 米野　寛
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1984-02-03
Filing date: 1984-02-03
Publication date: 1985-08-26

Abstract

PURPOSE:To provide a thermal energy storage material which is inexpensive, shows consistent heat absorbing and releasing performance and stores a large amt. of thermal energy per unit weight or unit volume, prepd. by adding a specified nucleator to a system consisting of CH3COONa and water. CONSTITUTION:The thermal energy storage material is prepd. by adding at least one nucleator selected from among NH4F, CrF3 and CoSiF6 to a system consisting of CH3COONa and water. The material shows almost no supercooling, is inexpensive, has consistent heat absorbing and releasing performance and stores a large amt. of thermal energy per unit weight or unit volume.

Description

【発明の詳細な説明】産業上の利用分野本発明は、酢酸ナトリウム３水塩を主体とする潜熱蓄熱
材に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a latent heat storage material mainly composed of sodium acetate trihydrate.

従来例の構成とその問題点一般的に、蓄熱材には、物質の顕熱を利用したものと潜
熱を利用したものが知られている。潜熱を利用した蓄熱
材は、顕熱を利用した蓄熱材に比較して、単位重量当シ
、捷たは単位体積当りの蓄熱量が大きく、必要量の熱を
蓄熱しておくのに少量でよく、そのため蓄熱装置の小型
化が可能となる。また、潜熱を利用した蓄熱材は、顕熱
を利用した蓄熱材のように、放熱とともに温度が低下し
てしまわずに、転移点において一定温度の熱を放熱する
という特徴を有する。特に、無機水化物の融解潜熱を利
用した蓄熱材は、単位体積当りの蓄熱量が大きいことが
知られている。Conventional Structures and Problems There are generally 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, heat storage materials that use latent heat have a larger amount of heat storage per unit weight, per unit volume, and require only a small amount to store the required amount of heat. Therefore, it is possible to downsize the heat storage device. In addition, a heat storage material that uses latent heat has the characteristic that unlike a heat storage material that uses sensible heat, the temperature does not drop with heat radiation, and instead radiates heat at a constant temperature at a transition point. In particular, heat storage materials that utilize the latent heat of fusion of inorganic hydrates are known to have a large amount of heat storage per unit volume.

ところで、従来より酢酸ナトリウム３水塩（Ｎ’　ａ　
ＣＨ３ＣＯ○・３Ｈ２０，融点約６８℃）は無機水化物
の中でも蓄熱量が大きく、たとえば暖房用の蓄熱材とし
て有力視されていた。しかしＮａＣＨ３Ｃｏ０・３Ｈ２
０は一度融解すると、非常に過冷却状態になりやすいた
め、その融解液は通常−２０℃程度まで冷却されないと
過冷却が破れない。そして、過冷却状態は、凝固点まで
冷却されても、融解潜熱を放出せず、その温度以下に冷
却されてしまう現象であるから、融解潜熱を利用した蓄
熱材にとって致命的欠点となる。By the way, conventionally sodium acetate trihydrate (N'a
CH3CO○.3H20, melting point approximately 68°C) has a large amount of heat storage among inorganic hydrates, and was considered to be a promising heat storage material for heating, for example. However, NaCH3Co0・3H2
Once 0 melts, it is very easy to become supercooled, so the supercooling will not break unless the melt is cooled to about -20°C. The supercooled state is a phenomenon in which even when cooled to the freezing point, the latent heat of fusion is not released and the material is cooled below that temperature, which is a fatal drawback for heat storage materials that utilize the latent heat of fusion.

発明の目的本発明は、酢酸ナトリウムの過冷却現象を防止し、安価
で、吸放熱性能の安定した単位重量当りもしくは単位体
積当りの蓄熱量の大きい蓄熱材を提供しようとするもの
である。OBJECTS OF THE INVENTION The present invention aims to provide a heat storage material that prevents the supercooling phenomenon of sodium acetate, is inexpensive, has stable heat absorption and radiation performance, and has a large amount of heat storage per unit weight or unit volume.

発明の構成本発明のもっとも特徴とするところは、酢酸ナトリウム
（Ｎ　ａ　ＣＨｓ　ＣＯＯ）と水とよりなる系を主成分
とし、ＮａＣＨ３Ｃｏ０・３Ｈ２０の結晶化の際の過冷
却を防止するだめの結晶核形成材として、フッ化アンモ
ニウム（ＮＨ４Ｆ）、フッ化クロム（Ｃｒ　Ｆ　３）な
らびにケイフッ化コバルト（Ｃｏ　Ｓ　ｔ　Ｆｅ　）よ
りなる化合物群より選ばれた少なくとも１種を前記の酢
酸ナトリウムと水よりなる系に混合することにある。Structure of the Invention The most characteristic feature of the present invention is that the main component is a system consisting of sodium acetate (N a CHs COO) and water, and a crystal nucleus is used to prevent supercooling during the crystallization of NaCH3Co0.3H20. As a forming material, at least one selected from the group of compounds consisting of ammonium fluoride (NH4F), chromium fluoride (CrF3), and cobalt silicofluoride (CoStFe) is added to the above-mentioned system consisting of sodium acetate and water. It consists in mixing.

実施例の説明第１図にＮ　ａ　ＣＨ３ＣＯ〇−Ｈ２Ｏ系の状態図を示
す。DESCRIPTION OF EXAMPLES FIG. 1 shows a phase diagram of the N a CH3CO〇-H2O system.

この図より、Ｎ　ａ　ＣＨ３ｃＯｏ　６０−３重量％と
Ｈ２Ｏ３９，７重量係トカらナル系はＮａＣＨ３Ｃｏ０
・３Ｈ２゜組成に相当し、この組成では、過冷却が起こ
らなければ約６８℃で融解と凝固が起こるのがわかる。From this figure, NaCH3cOo 60-3% by weight and H2O39.7% by weight are NaCH3Co0
- Corresponds to the 3H2° composition, and it can be seen that with this composition, melting and solidification occur at about 68°C unless supercooling occurs.

また、Ｎ　ａ　ＣＨｓ　ＣＯＯ５０重量％とＨ２Ｏ５ｏ
重量％の系は、約５６℃以上の温度では均一なＮ　ａ　
ＣＨｓ　ＣＯＯ水溶液となる。この均一な水溶液を６６
℃以下に冷却すると、過冷却が起こらなければ、Ｎ　ａ
　ＣＨｓ　ＣＯＯ・３　Ｈ２０が結晶化しはじめ、冷却
されるに従ってＮ　ａ　ＣＨ３ＣＯ０・３Ｈ２ｏ結晶の
比率が増加する。約３０’Ｃまで冷却されると、５゜重
量％　ＯＮ　ａ　ＣＨ３ＣＯＯ−Ｈ２０系全質量の約６
０％がＮａＣＨ３ＣＯＯ・３Ｈ２ｏの結晶となり、残り
４０チがＮ　ａ　ＣＨ３ＣＯＯ水溶液として存在する。In addition, N a CHs COO50% by weight and H2O5o
wt% system has a uniform Na
It becomes a CHs COO aqueous solution. This homogeneous aqueous solution is
When cooled to below ℃, if supercooling does not occur, Na
CHs COO·3 H20 begins to crystallize, and as it cools, the proportion of Na CH3CO0·3H2o crystals increases. When cooled to about 30'C, 5% by weight ON a about 6 of the total mass of the CH3COO-H20 system.
0% becomes crystals of NaCH3COO.3H2o, and the remaining 40% exists as an aqueous solution of NaCH3COO.

そのため、Ｎ　ａ　ＣＨ３ＣＯ○６０重量％と６２０５
０％の系は、６６℃以上の温度から３０℃まで冷却され
ると、過冷却カホトントナく、ＮａＣＨ３ＣＯＯ・３Ｈ
２ｏがうまく結晶化したとすると、単位質量当りＮ　ａ
　ＣＨ３ＣＯＯ・３　Ｈ２０組成の場合の約６０チの潜
熱が得られることになる。また、Ｎ　ａ　ＣＨ３ＣＯＯ
−Ｈ２Ｏ系の水の比率が高くなるとともに、蓄熱材の有
する顕熱が増加し、顕熱による蓄熱量が大きくなるのは
当然である。つまり、Ｎ　ａ　ＣＨ３ＣＯＯとＨ２Ｏの
比率をコントロールすることによって、融解潜熱による
蓄熱と、顕熱による蓄熱を併用して行い、その潜熱と顕
熱による蓄熱の割合をコントロールすることによって、
大喜←蓄熱材の応用範囲が広がる。しかし、あまりＮ　
ａ　ＣＨａＣＯＯの濃度の低い系を用いることは、融解
潜熱を用いた蓄熱材の特徴が失なわれてしまうため、Ｎ
　ａ　ＣＨ３ＣＯＯを４０重量％以上含有するＮ　ａ　
ＣＨ２ＯＯＯＨ２０系を用いるのが適切である。Therefore, Na CH3CO○60% by weight and 6205
When the 0% system is cooled from a temperature above 66°C to 30°C, it becomes supercooled and NaCH3COO.3H
Assuming that 2o is successfully crystallized, Na per unit mass
A latent heat of about 60 H is obtained for the CH3COO.3H20 composition. Also, Na CH3COO
It is natural that as the ratio of -H2O water increases, the sensible heat possessed by the heat storage material increases, and the amount of heat storage due to sensible heat increases. In other words, by controlling the ratio of Na CH3COO and H2O, heat storage by latent heat of fusion and heat storage by sensible heat are performed together, and by controlling the ratio of heat storage by latent heat and sensible heat,
Great joy←The range of applications for heat storage materials will expand. However, too much N
a If a system with a low concentration of CHaCOO is used, the characteristics of a heat storage material using latent heat of fusion will be lost, so N
a Na containing 40% by weight or more of CH3COO
It is appropriate to use the CH2OOOH20 system.

逆に、ＮａＣＨ３ＣＯＯ−Ｈ２０系においてＮａ　σ３
ＣＯＯの含有量を増加させていくと、第１図よシ明らか
なように、Ｎ　ａ　ＣＨ５ＣＯＯを６０．３重量％以上
含有する系では、６８℃以上の温度からその温度以下に
冷却した際、゛うま〈過冷却が破れたとすると、Ｎ　ａ
　ＣＨ３ＣＯｏ・３Ｈ２０が結晶化する。しかし、当然
系全体がＮａＣＨ３Ｃ０ｏ・３Ｈ２０とならず、一部は
単位質量当りの潜熱量がＮａＣＨ３ＣＯＯ・３Ｈ２ｏ組
成の場合の約６０％以下になるため実用的でなくなる。Conversely, in the NaCH3COO-H20 system, Na σ3
As the COO content increases, as is clear from Figure 1, in a system containing 60.3% by weight or more of Na CH5COO, when cooled from a temperature of 68°C or higher to a temperature below that temperature,゛Uma〈If supercooling is broken, Na
CH3COo.3H20 crystallizes. However, of course, the entire system does not become NaCH3C0o.3H20, and the amount of latent heat per unit mass of some parts becomes less than about 60% of that in the case of the NaCH3COO.3H2o composition, making it impractical.

そのため、実際に用いるＮ　ａ　ＣＨ３ＣＯＯ−Ｈ２０
系は、Ｎ　ａ　ＣＨ３ＣＯＯを８０重量％以下の範囲で
含ム（ＮＨ４Ｆ　）　、フッ化り０　ム（ＣｒＦ３）　
、　ナラヒにケイフッ化コバルト（Ｃｏ　Ｓ　ｓ　Ｆｅ
　）よりなる化合物群より選択された少なくとも１種で
ある場合には、ＮａＣＨ３ＣＯＯとＨ２Ｏよりなる１０
０重量部に対して１．０重量部程度で十分傾効果があシ
、さらにそれ以上含有しても、当然に効果がある。Therefore, actually used Na CH3COO-H20
The system contains Na CH3COO in a range of up to 80% by weight (NH4F) and 0% fluoride (CrF3).
, Cobalt silicofluoride (Co S s Fe
) is at least one selected from the group of compounds consisting of 10 consisting of NaCH3COO and H2O.
About 1.0 parts by weight relative to 0 parts by weight provides a sufficient tilting effect, and even if more than 1.0 parts by weight is contained, it is naturally effective.

Ｎ　ａ　ＣＨｓ　ＣＯＯが６８重量％未満である系の場
合には、それが６８重量％以上含まれている系に比較し
て、結晶核形成材のＮ　ａ　ＣＨｓｃ　ＯＯ−Ｈ２０系
中への溶解量が増加するため、それぞれの添加量を上記
値より増加させなければならない。In the case of a system in which Na CHs COO is less than 68% by weight, the amount of crystal nucleation material dissolved in the Na CHsc OO-H20 system is lower than that in a system in which it is contained at 68% by weight or more. increases, so the amount of each addition must be increased from the above values.

しかしながら、本発明にかかる蓄熱材を空調用蓄熱装置
等で使用する際には、１００〜１０００に９程度用いる
のが普通であると考えられる。そのような場合には、Ｎ
ａＣＨ３Ｃ０ｏ・３Ｈ２０結晶が融解した状態において
も、全体が均一な組成にならず、上部にはＮ　ａ　ＣＨ
ｓ　ＣＯＯの低濃度の溶液が、下部には結晶核形成材の
沈澱物、およびＮ　ａ　ＣＨ３ＣＯＯと結晶核形成材と
の高濃度液体が存在することになる。そのため、結晶核
形成材の混合量が、均一な溶液を形成する場合の最少量
に比較してはるかに少量でも、結晶核形成材がＮａ　Ｃ
Ｈ３ＣＯＯ−Ｈ２０系中に溶解してしまわずに結晶核形
成材として作用する。結晶核形成に必要な前記結晶核形
成材の最少量つまり混合量の下限は、用いるＮａ　ＣＨ
３ＣＯ０−Ｈ２Ｏ系の量や蓄熱材を収納する容器の形状
に依存するため、その使用形態に応じてそれぞれについ
て適宜決めてやればよい。However, when the heat storage material according to the present invention is used in a heat storage device for air conditioning, etc., it is considered normal to use the heat storage material in a ratio of about 9 out of 100 to 1000. In such a case, N
Even when the aCH3C0o/3H20 crystal is in a molten state, the composition is not uniform throughout, and the upper part contains Na CH
There will be a solution with a low concentration of s COO, a precipitate of nucleating material at the bottom, and a liquid with a high concentration of Na CH3COO and nucleating material. Therefore, even if the amount of the crystal nucleation material mixed is much smaller than the minimum amount for forming a homogeneous solution, the crystal nucleation material is NaC.
It acts as a crystal nucleation material without being dissolved in the H3COO-H20 system. The minimum amount of the crystal nucleation material necessary for crystal nucleation, that is, the lower limit of the mixing amount, is the Na CH
Since it depends on the amount of the 3CO0-H2O system and the shape of the container housing the heat storage material, it may be determined appropriately for each depending on the usage pattern.

しかし、あまり大量に結晶核形成材を加えることは、蓄
熱材として好ましいことではなく、蓄熱材全体として見
た場合の蓄熱量の減少につながる。However, adding too much crystal nucleation material is not preferable as a heat storage material, and leads to a decrease in the amount of heat storage in the heat storage material as a whole.

そのため、実用的には、結晶核形成材の混合割合は、Ｎ
ａＣＨ３Ｃｏｏ−Ｈ２Ｏ系１００重量部に対して、４０
重量部を超えないことが望ましい。Therefore, in practice, the mixing ratio of the crystal nucleation material is N
For 100 parts by weight of aCH3Coo-H2O system, 40
It is desirable not to exceed parts by weight.

実施例１ＮａＣＨ３Ｃｏｏ−３Ｈ２０１ｏｏｏｙと第１表に示し
た結晶核形成材１０ｙをビーカーに入れ、ウォーターバ
ス中で７６℃捷で加熱して、Ｎ　ａ　ＣＨｓ　ＣＯｏ・
３Ｈ２ｏをすべて融解した。この混合物を内径１００ｍ
ｍ、長さ１００ｍ＋ｎの円筒形容器に収納し、熱電対挿
入管を付した栓で密封した。その容器をウォーターバス
中に入れ、７６℃と４ｏ℃の間で加熱冷却を連続して行
った。Example 1 NaCH3Coo-3H201oooy and the crystal nucleation material 10y shown in Table 1 were placed in a beaker and heated at 76°C in a water bath to form NaCHsCOo.
All 3H2o was melted. This mixture has an inner diameter of 100 m.
The container was placed in a cylindrical container with a length of 100 m+n and sealed with a stopper equipped with a thermocouple insertion tube. The container was placed in a water bath and heated and cooled continuously between 76°C and 4o°C.

第２図は、結晶核形成材として、フッ化アンモニウムを
用いた場合の試料を、連続して１００回加熱と冷却を繰
り返した際の過冷却度すなわち凝固温度と過冷却の破れ
る温度との差の変化の様子を示したものである。図の横
軸は加熱冷却サイクルの繰り返し回数を対数目盛で示し
たものであり、縦軸は過冷却度（℃）である。この図よ
り、本実施例の蓄熱材の加熱および冷却を１００回繰シ
返しても、過冷却度が３〜４℃の範囲で安定しており、
過冷却防止機能は劣化せずに、有効に作用しているのが
わかる。Figure 2 shows the difference between the degree of supercooling, that is, the solidification temperature, and the temperature at which supercooling breaks when a sample is repeatedly heated and cooled 100 times using ammonium fluoride as a crystal nucleation material. This figure shows the changes in . The horizontal axis of the figure shows the number of repetitions of the heating/cooling cycle on a logarithmic scale, and the vertical axis shows the degree of supercooling (° C.). From this figure, even if the heating and cooling of the heat storage material of this example is repeated 100 times, the degree of supercooling remains stable in the range of 3 to 4°C.
It can be seen that the supercooling prevention function is working effectively without deterioration.

第　１　表第３図は結晶核形成材としてフッ化クロムを用いた場合
、第４図はケイフッ化コバルトを用いた場合である。こ
れらの実施例の試料はいずれも、過冷却度が３〜４℃付
近で非常に安定している。Table 1, Figure 3 shows the case where chromium fluoride was used as the crystal nucleation material, and Figure 4 shows the case where cobalt silicofluoride was used. All of the samples of these Examples are very stable at a degree of supercooling of around 3 to 4°C.

実施例２Ｎ　ａ　ＣＨ３Ｃ００＠４’Ｈ２０６００ｙ（！：第１
表に示り、ｆｃ結晶核形伐材６ｏＯｙとを内部にヒータ
を有する内径８０循、高さ９０６ｇ１の円筒形容器中に
収納し、熱電対挿入管を付したふたで密封した。容器内
部１ｏ　、のヒータでＮａＣＨ３Ｃｏ０・３Ｈ２０を７０℃まで加
熱して、Ｎ　ａ　ＣＨ３ＣＯ０・３　Ｈ２０をすべて融
解した。Example 2 N a CH3C00@4'H20600y (!: 1st
As shown in the table, 6000 y of fc crystal nucleus cutting material was placed in a cylindrical container with an inner diameter of 80 cycles and a height of 906 g1, which had a heater inside, and was sealed with a lid equipped with a thermocouple insertion tube. NaCH3Co0.3H20 was heated to 70° C. with a heater located inside the container, and all of the NaCH3CO0.3H20 was melted.

それからヒータによる加熱を停止し、冷却したところ、
結晶核形成材としてフッ化アンモニウム。Then, when the heater stopped heating and cooled down,
Ammonium fluoride as a crystal nucleation material.

フッ化クロムならびにケイフッ化コバルトのいずれを用
いた場合にも６６℃付近で過冷却が破れ、容器内部の温
度が５８℃まで上昇した。その後６０回加熱と冷却を繰
返したが、いずれの場合も過冷却度が約３℃の所で安定
して過冷却が破れ、本実施例の蓄熱材が十分蓄熱材とし
て機能することが確認出来た。In both cases where chromium fluoride and cobalt silicofluoride were used, supercooling broke down at around 66°C, and the temperature inside the container rose to 58°C. After that, heating and cooling were repeated 60 times, but in each case, the supercooling was broken stably at a degree of supercooling of about 3°C, confirming that the heat storage material of this example sufficiently functions as a heat storage material. Ta.

比較例１ＮａＣＨ３ＣＯｏ・３Ｈ２０１ｏｏｏｙを実施例１と同
様の容器に収納し、７６℃まで加熱してＮａＣＨ３Ｃｏ
０・３Ｈ２０をすべて融解した。その後、冷却した所、
室温まで達してもＮ　ａ　ＣＨ３ＣＯ０・３Ｈ２ｏは結
晶化しなかった。Comparative Example 1 NaCH3COo.3H201oooy was stored in the same container as in Example 1 and heated to 76°C to form NaCH3Co
All of the 0.3H20 was melted. Then, after cooling,
Even when the temperature reached room temperature, Na CH3CO0.3H2o did not crystallize.

比較例２ＮａＣＨ３ＣＯｏ・３Ｈ２ｏ　５ｏｏＫｇを実施例２と
同様の容器に収納し、容器内部のヒータでＮａ　ＣＨ３
ＣＯＯ・−−３３Ｈ２０を７０℃まで加熱して、ＮａＣＨ３ＣＯＯ・３
）Ｉ２０をすべて融解した。その後ヒータによる加熱を
停止して冷却したところ、室温まで過冷却してしまった
・発明の効果以上実施例で示したように、本発明の蓄熱材はＮａＣＨ
３ＣＯＯ−Ｈ２Ｏ系に、ＮａＣＨ３ＣＯＯ＃３Ｈ２０の
結晶核形成材としてンッ化アンモニウム、フッ化クロム
ならびにケイフッ化コバルトよシ成る化合物群より１種
を加えた混合物であるから過冷却のほとんど示さない安
定した吸収熱性能を有し、安価でかつ蓄熱量の大きなも
のとなっている。そして、実施例ではこれら結晶核形成
材を単独で使用した場合について示しているが、その複
数種を組合わせて使用しても同等の作用効果を得ること
ができるものである。Comparative Example 2 5ooKg of NaCH3COo・3H2o was stored in the same container as in Example 2, and Na CH3 was heated using a heater inside the container.
COO・--3 Heating 3H20 to 70℃, NaCH3COO・3
) I20 was all melted. After that, when the heating by the heater was stopped and the temperature was cooled, it was supercooled to room temperature.
Because it is a mixture of 3COO-H2O system and one compound from the compound group consisting of ammonium fluoride, chromium fluoride, and cobalt silicofluoride as a crystal nucleation material for NaCH3COO#3H20, it has stable absorption with almost no supercooling. It has thermal performance, is inexpensive, and has a large amount of heat storage. Although the examples show cases in which these crystal nucleation materials are used alone, equivalent effects can be obtained even when a plurality of these materials are used in combination.

本発明の蓄熱材は、空調用の蓄熱装置だけでなく、蓄熱
式保温器等の蓄熱を利用するあらゆる方面に応用可能な
ものである。The heat storage material of the present invention is applicable not only to heat storage devices for air conditioning, but also to all fields that utilize heat storage, such as heat storage type heat insulators.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は酢酸ナトリウム−水系の状態図、第２図から第
４図は本発明にかかる蓄熱材の実施例を１００回繰り返
し加熱・冷却したときの過冷却度の変化の様子を示すグ
ラフである。代理人の氏名　弁理士　中　尾　敏　男　ほか１名第１
図第２図ｄｌすηし回」嵯（町第３図斥り辺し旧家（＠ンFigure 1 is a phase diagram of the sodium acetate-water system, and Figures 2 to 4 are graphs showing changes in the degree of supercooling when the heat storage material according to the present invention is repeatedly heated and cooled 100 times. be. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
fig.

Claims

【特許請求の範囲】[Claims]

（１）　酢酸ナトリウム（Ｎ　ａ　ＣＨ３ｃｏ○）と水
（Ｈ２Ｏ）より成る系に、フッ化アンモニウム（ＮＨ４
Ｆ）、フッ化クロム（Ｃｒ　Ｆ３）　、表らびにケイフ
ッ化コバルト（ＣｏＳｉＦ６）よりなる化合物群より選
択された少なくとも１種の結晶核形成材を含有させたこ
とを特徴とする蓄熱材。(1) Ammonium fluoride (NH4
F), chromium fluoride (CrF3), and cobalt silicofluoride (CoSiF6).

（２）酢酸ナトリウムと水とよりなる系において、酢酸
ナトリウムが４０〜８０重量係含まれていることを特徴
とする特許請求の範囲第１項記載の蓄熱材。(2) The heat storage material according to claim 1, characterized in that the system consisting of sodium acetate and water contains 40 to 80% by weight of sodium acetate.

（３）酢酸ナトリウムと水とよりなる系１００重量部に
対する結晶核形成材の配合量が４０重量部を超え々いこ
とを特徴とする特許請求の範囲第１項記載の蓄熱材。(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 sodium acetate and water is more than 40 parts by weight.