JP2007246778A - Heat storing agent and method of preparing heat storing agent - Google Patents
Heat storing agent and method of preparing heat storing agent Download PDFInfo
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Abstract
Description
本発明は、冷暖房などの空調設備や、食品等の冷却装置に用いられる蓄熱剤及び蓄熱剤の調製方法に関する。 The present invention relates to a heat storage agent used for air conditioning equipment such as air conditioning and cooling devices for foods and the like, and a method for preparing the heat storage agent.
潜熱蓄熱剤は、顕熱蓄熱剤に比べて蓄熱密度が高く、相変化温度が一定であり、熱の取り出し温度が安定である等の利点があるため、種々の用途に実用化されている。
また、空調システムにおいては設備費や運転費の削減のため、熱媒体を輸送するポンプ動力の低減が求められており、熱輸送密度を増大させるために蓄熱密度の高い潜熱蓄熱剤を用いることが検討されている。
Since the latent heat storage agent has advantages such as a higher heat storage density than the sensible heat storage agent, a constant phase change temperature, and a stable heat extraction temperature, it has been put to practical use in various applications.
In air conditioning systems, reduction of pump power for transporting the heat medium is required to reduce equipment costs and operating costs, and in order to increase heat transport density, it is necessary to use a latent heat storage agent with a high heat storage density. It is being considered.
このような潜熱蓄熱剤として、トリメチロールエタンやテトラアルキルアンモニウム化合物の包接水和物が知られている。
テトラアルキルアンモニウム化合物の包接水和物は、水和物を生成する際の潜熱が大きいため、比較的蓄熱量が大きく、またパラフィンのように可燃性ではないため取り扱いも容易であり、非常に有用な蓄熱剤である。
As such latent heat storage agents, clathrate hydrates of trimethylolethane and tetraalkylammonium compounds are known.
The clathrate hydrate of tetraalkylammonium compound has a large latent heat when forming a hydrate, so it has a relatively large amount of heat storage, and it is not flammable like paraffin, so it is easy to handle. It is a useful heat storage agent.
また、テトラアルキルアンモニウム化合物の包接水和物は、調和融点が氷の融点の0℃よりも高いため、蓄熱剤を冷却して水和物を生成する際の冷媒の温度が高くてよく、冷凍機の成績係数（COP）が高くなり省エネルギーが図れるという利点もある。
なお、調和融点とは水和物を生成する化合物の水溶液を冷却して水和物を生成する際、水溶液（液相）から水和物（固相）に変相する前後の組成が変わらない場合（例えばもとの水溶液中の水和物を生成する化合物濃度と同じ濃度の水和物を生じる）の温度をいう。なお、縦軸を融点温度、横軸を濃度とした状態図では極大点が調和融点となる。本発明では調和融点を与える濃度を調和濃度という。
調和濃度の水溶液を冷却すると、調和融点で水和物が生成しはじめ、水溶液が全て水和物になるまでこの融点温度で温度は一定になる。融解時も同様にこの一定の融点温度で融解する。また、水和物の凝固融解時の潜熱量は調和濃度で最大となる。
調和濃度より濃度が低くなるか高くなると、融解温度は調和融点より低くなる。
In addition, since the clathrate hydrate of the tetraalkylammonium compound has a harmonic melting point higher than the melting point of ice, 0 ° C., the temperature of the refrigerant when the heat storage agent is cooled to produce the hydrate may be high, There is also an advantage that the coefficient of performance (COP) of the refrigerator can be increased and energy can be saved.
The harmonic melting point means that the composition before and after the phase change from an aqueous solution (liquid phase) to a hydrate (solid phase) does not change when an aqueous solution of a compound that forms a hydrate is cooled to produce a hydrate. The temperature of the case (eg, producing a hydrate with the same concentration as the compound concentration that produces the hydrate in the original aqueous solution). In the state diagram in which the vertical axis represents the melting point temperature and the horizontal axis represents the concentration, the maximum point is the harmonic melting point. In the present invention, the concentration that provides the harmonic melting point is referred to as the harmonic concentration.
When an aqueous solution with a harmonic concentration is cooled, hydrates begin to form at the harmonic melting point, and the temperature is constant at this melting temperature until all aqueous solutions are hydrated. Similarly, melting occurs at this constant melting temperature. In addition, the amount of latent heat at the time of solidification and melting of the hydrate is maximized at the harmonic concentration.
When the concentration is lower or higher than the harmonic concentration, the melting temperature becomes lower than the harmonic melting point.
潜熱蓄熱剤を用いた空調においては、冷熱源からの冷熱を潜熱として貯めている蓄熱剤と空調負荷の空気とを直接又は媒体を介して熱交換を行い、熱交換後の空気を空調対象の空間に送り出すことにより、その空間の温度や湿度を調整している。
多くの場合、冷房空調において室内機から吹き出す冷空気の温度は一般に15℃程度であり、高くとも18℃程度である。それ以上に高い温度であると、空調対象の空間に向けて送り出すべき空気量を増やさない限り、同レベルの空調効果を得ることが困難になり、それどころか却って空調効率が低下する。そのため、冷空気に冷熱を供給する潜熱蓄熱剤は、空気との熱交換に必要な温度差（約2℃）を考慮して、16℃以下の潜熱を蓄熱できるものであることが要求される。
In air conditioning using a latent heat storage agent, heat exchange between the heat storage agent that stores the cold heat from the cold heat source as latent heat and the air of the air conditioning load is performed directly or through a medium, and the air after the heat exchange is The temperature and humidity of the space are adjusted by sending it out to the space.
In many cases, the temperature of the cold air blown out from the indoor unit in the cooling air-conditioning is generally about 15 ° C., and about 18 ° C. at the highest. If the temperature is higher than that, it is difficult to obtain the same level of air-conditioning effect unless the amount of air to be sent out toward the space to be air-conditioned is increased. On the contrary, the air-conditioning efficiency is lowered. Therefore, a latent heat storage agent that supplies cold air to cold air is required to be able to store latent heat of 16 ° C or less in consideration of the temperature difference (about 2 ° C) required for heat exchange with air. .
また、空調向けの潜熱蓄熱剤の典型例である氷の場合、0℃以下で冷却する必要があるため、冷凍機のCOPが低くなり、冷房に必要なエネルギーが大きくなり省エネルギー化ができないという問題があった。COPを高いまま維持し、省エネルギー化を実現するためには、空調向けの潜熱蓄熱剤は、5℃以上、低くとも3℃以上で蓄熱できるものであることが要求される。
以上のような理由から、3〜16℃の温度範囲で蓄熱できる空調向けの潜熱蓄熱剤が望まれている。
In addition, in the case of ice, which is a typical example of a latent heat storage agent for air conditioning, it is necessary to cool at 0 ° C or less, so the COP of the refrigerator is low, the energy required for cooling increases, and energy saving cannot be achieved was there. In order to maintain high COP and achieve energy saving, latent heat storage agents for air conditioning are required to be able to store heat at 5 ° C or higher and at least 3 ° C or higher.
For these reasons, a latent heat storage agent for air conditioning that can store heat in a temperature range of 3 to 16 ° C. is desired.
この温度範囲で蓄熱できる空調向けの潜熱蓄熱剤として、包接水和物を蓄熱主剤とするものが知られている（特許文献１参照）。特に臭化テトラブチルアンモニウム（ＴＢＡＢ）は、調和融点がおよそ12℃で、潜熱量は約180J/gであり、空調用蓄熱剤として用いることが開示されている。 As a latent heat storage agent for air conditioning that can store heat in this temperature range, a clathrate hydrate as a heat storage main agent is known (see Patent Document 1). In particular, tetrabutylammonium bromide (TBAB) has a harmonic melting point of about 12 ° C. and a latent heat of about 180 J / g, and is disclosed to be used as a heat storage agent for air conditioning.
また、トリメチロールエタン（ＴＭＥ）、水及び尿素を含有する水和物系蓄熱剤主成分に、ポリグリセリンを添加した蓄熱剤が開示されており、その融点は１０〜２５℃である（特許文献２参照）。 Moreover, the thermal storage agent which added the polyglycerin to the hydrate type thermal storage agent main component containing a trimethylol ethane (TME), water, and urea is disclosed, The melting | fusing point is 10-25 degreeC (patent document) 2).
水和物生成物の水溶液を冷却して、水和物生成温度（融点）に達してさらに低温になっても水和物が生成されず水溶液の状態を保っている状態を過冷却というが、水和物を蓄熱剤に用いる場合にはこの過冷却が大きいと、水溶液を冷却するための冷媒温度を低くしなければならず、また水和物の生成が遅延するなど問題となる。したがって、過冷却をできるだけ小さくし、過冷却を防止することが重要である。
この点、過冷却を防止するために、従来から微粒子を蓄熱剤に混入し水和物の核生成材として過冷却を防止することが行われている。しかし、水和物を生成する際の過冷却を防止するために微粒子を混入させたとしても、微粒子が均一に分散されていないと過冷却防止効能がなくなるという問題や、凝固と融解を繰り返すと微粒子が分離されて過冷却防止効能がなくなるという問題がある。そのため、最近では微粒子を添加するのではなく、過冷却防止剤を添加する方法が検討されている。
Although the aqueous solution of the hydrate product is cooled and the hydrate formation temperature (melting point) is reached and the temperature is further lowered, the hydrate is not formed and the state of the aqueous solution is maintained. When this hydrate is used as a heat storage agent, if this supercooling is large, the refrigerant temperature for cooling the aqueous solution must be lowered, and the production of the hydrate is delayed. Therefore, it is important to make the supercooling as small as possible and prevent the supercooling.
In this regard, in order to prevent overcooling, it has been conventionally practiced to prevent supercooling by mixing fine particles into a heat storage agent as a nucleation material of a hydrate. However, even if fine particles are mixed to prevent supercooling when producing hydrates, the problem that the effect of preventing overcooling is lost unless the fine particles are uniformly dispersed, and if solidification and melting are repeated There is a problem that fine particles are separated and the effect of preventing overcooling is lost. Therefore, recently, a method of adding a supercooling inhibitor instead of adding fine particles has been studied.
例えば、蓄熱主剤であるテトラブチル硝酸アンモニウムに対し、テトラアルキルアンモニウム塩水和物を過冷却防止剤とするもの（特許文献３参照）や、気体水和物の蓄熱主剤であるテトラハイドロフラン、トリメリルアミン等に対し、テトラブチルアンモニウム塩水和物やテトライソアミルアンモニウム水和物を過冷却防止剤として使用するもの（特許文献４、特許文献５参照）が開示されている。 For example, with respect to tetrabutylammonium nitrate as a heat storage main agent, a tetraalkylammonium salt hydrate as a supercooling inhibitor (see Patent Document 3), tetrahydrofuran as a heat storage main agent for gas hydrate, trimerylamine, etc. On the other hand, those using tetrabutylammonium salt hydrate or tetraisoamylammonium hydrate as a supercooling preventive agent (see Patent Literature 4 and Patent Literature 5) are disclosed.
特許文献３〜５に記載されたものは、いずれも、蓄熱主剤に対し過冷却防止剤を微量使用することを特徴としている。即ち、特許文献３に記載のものでは、過冷却防止剤を微量（０．１重量％以下）用いており、特に多孔質物質にこれを含浸させて蓄熱主剤が存在する水溶液に添加することで過冷却防止を実現している。
また、特許文献４に記載のものでは、１〜１００μｍの小孔を備える厚さ２ｍｍの多孔質物質を隔壁として、過冷却防止剤を蓄熱主剤が存在する水溶液側に移動させることで過冷却を防止している。
さらに、特許文献５に記載のものでは、気体水化物のゲル化物に、孔径５〜３００μｍの毛細管中又は孔径３００μｍ以下の多孔質物質中に過冷却防止剤を充填したものを分散させることで過冷却を防止している。
また、特許文献２では、トリメチロールエタン（ＴＭＥ）、水及び尿素を含有する水和物系蓄熱剤主成分に、ポリグリセリンを添加した蓄熱剤に、過冷却防止剤として硫酸カルシウム、硫酸カルシウム水塩等の無機塩又は無機水和塩を配合している。
Each of those described in Patent Documents 3 to 5 is characterized in that a supercooling inhibitor is used in a very small amount with respect to the heat storage main agent. That is, in the thing of patent document 3, a supercooling inhibitor is used in a trace amount (0.1 wt% or less), and especially by impregnating this with a porous material and adding it to an aqueous solution containing a heat storage main agent. Prevents overcooling.
Moreover, in the thing of patent document 4, supercooling is carried out by moving a supercooling inhibitor to the aqueous solution side in which a heat storage main agent exists by using a porous material with a thickness of 2 mm having a small hole of 1 to 100 μm as a partition wall. It is preventing.
Furthermore, in the thing of
In Patent Document 2, trimethylolethane (TME), a hydrate-based heat storage agent containing water and urea as a main component, a heat storage agent in which polyglycerin is added, calcium sulfate and calcium sulfate water as a supercooling preventive agent. An inorganic salt such as a salt or an inorganic hydrated salt is blended.
水和物生成物の水溶液を冷却していく過程で、過冷却防止剤が水和物形成の核となり、過冷却防止するが、特許文献３から５において、蓄熱主剤たる水和物を生成する水溶液に過冷却防止剤が接触する場所は、局所的である。このような場合、まず過冷却防止剤と接触している水溶液の部分から水和物が形成され、その水和物の周囲の水溶液からさらに水和物が形成されるので、過冷却防止効果が水溶液全体に及ぶまでには時間がかかり、全体として過冷却が十分に防止され包接水和物の生成が円滑に行われるとは言い難い。そのため、蓄熱を短時間で行うため水和物の生成を急速に行う必要がある場合には大きな問題となる。 In the process of cooling the aqueous solution of the hydrate product, the supercooling preventive agent becomes the nucleus of hydrate formation and prevents supercooling. However, in Patent Documents 3 to 5, a hydrate as a heat storage main ingredient is generated. The place where the supercooling inhibitor contacts the aqueous solution is local. In such a case, a hydrate is first formed from the portion of the aqueous solution that is in contact with the supercooling preventive agent, and a hydrate is further formed from the aqueous solution around the hydrate. It takes time to reach the entire aqueous solution, and it is difficult to say that supercooling is sufficiently prevented as a whole, and clathrate hydrate is generated smoothly. Therefore, it becomes a big problem when it is necessary to generate hydrates rapidly in order to store heat in a short time.
また、そもそも過冷却防止剤を毛細管中に充填したり、孔径３００μｍ以下の多孔質物質に含浸させたり、充填させたりしただけでは、過冷却防止剤は十分に機能するとは言えず、また、過冷却防止効果を長期にわたって維持することはできない。そのため、蓄熱・放熱を頻繁に繰り返すために、包接水和物の生成と融解を繰り返す必要がある場合には、大きな問題となる。 In the first place, it cannot be said that the supercooling inhibitor functions sufficiently only by filling the capillary with the supercooling inhibitor, or impregnating or filling the porous material with a pore diameter of 300 μm or less. The anti-cooling effect cannot be maintained for a long time. Therefore, it becomes a big problem when it is necessary to repeat generation and melting of clathrate hydrate in order to frequently repeat heat storage and heat dissipation.
また、特許文献２のトリメチロールエタン（ＴＭＥ）、水及び尿素を含有する水和物系蓄熱剤主成分にポリグリセリンを添加した蓄熱剤では、トリメチロールエタン水和物系蓄熱剤で問題となる凝固融解の繰返しに伴って相分離が生じることをポリグリセリンを添加することにより改善する試みがなされている。しかしながら、特許文献２において、凝固融解の繰返しを確認した回数は１００回程度に留まっているので、実際の凝固融解の繰返し使用に耐え得るとは言い難く、相分離が生じると過冷却防止効果も長期にわたって維持することができないという問題がある。 Moreover, in the thermal storage agent which added the polyglycerin to the hydrate type thermal storage agent main component containing the trimethylol ethane (TME), water, and urea of patent document 2, it becomes a problem by a trimethylol ethane hydrate type thermal storage agent. Attempts have been made to improve the occurrence of phase separation with repeated solidification and melting by adding polyglycerin. However, since the number of repetitions of solidification and melting confirmed in Patent Document 2 is only about 100 times, it cannot be said that it can withstand repeated use of actual solidification and melting. There is a problem that it cannot be maintained for a long time.
本発明は、上記のような問題点を解決するためになされたものであり、空調向けの用途において要望される3〜16℃の温度範囲で多くの冷熱を蓄熱でき、過冷却防止効能が高く、また水和物の凝固と融解を頻繁に繰返しても過冷却防止効能を維持できる蓄熱剤及びその調製方法を提供することを目的とする。 The present invention has been made in order to solve the above-mentioned problems, and can store a large amount of cold in a temperature range of 3 to 16 ° C. that is required for applications for air conditioning. Another object of the present invention is to provide a heat storage agent capable of maintaining the effect of preventing overcooling even when the solidification and melting of the hydrate are frequently repeated, and a method for preparing the same.
（１）本発明に係る蓄熱剤は、臭化テトラｎブチルアンモニウム水和物からなる蓄熱剤主成分と、蓄熱剤主成分に対して１〜６重量％の弗化テトラｎブチルアンモニウム水和物を含有してなることを特徴とするものである。 (1) The heat storage agent according to the present invention comprises a heat storage agent main component comprising tetra nbutylammonium bromide hydrate, and 1 to 6% by weight of tetra nbutylammonium fluoride hydrate with respect to the heat storage agent main component. It is characterized by containing.
（２）また、本発明に係る蓄熱剤は、臭化テトラｎブチルアンモニウムの水溶液からなる蓄熱剤主成分と、蓄熱剤主成分に対して１〜６重量％の弗化テトラｎブチルアンモニウムの水溶液を添加してなることことを特徴とするものである。 (2) Moreover, the heat storage agent which concerns on this invention is the heat storage agent main component which consists of the aqueous solution of tetra n butylammonium bromide, and the aqueous solution of tetra n butyl ammonium fluoride of 1 to 6 weight% with respect to the heat storage agent main component. It is characterized by being added.
（３）また、本発明に係る蓄熱剤は上記（１）または（２）に記載のものにおいて、腐食抑制剤を添加したことを特徴とするものである。 (3) Further, the heat storage agent according to the present invention is characterized in that a corrosion inhibitor is added to the heat storage agent described in (1) or (2) above.
（４）本発明に係る蓄熱剤の調製方法は、臭化テトラｎブチルアンモニウムの水溶液からなる蓄熱剤主成分に、蓄熱剤主成分に対して１〜６重量％の弗化テトラｎブチルアンモニウムの水溶液を添加することを特徴とするものである。 (4) The method for preparing a heat storage agent according to the present invention comprises a heat storage agent main component comprising an aqueous solution of tetra nbutylammonium bromide, and 1 to 6% by weight of tetra nbutylammonium fluoride based on the heat storage agent main component. An aqueous solution is added.
臭化テトラｎブチルアンモニウム水和物は包接水和物を形成し、その調和融点はおよそ12℃であり、この調和融点における潜熱量は178J/gである。臭化テトラｎブチルアンモニウム水和物を蓄熱剤主成分として、過冷却防止効能を有する蓄熱剤配合組成を検討し、弗化テトラｎブチルアンモニウム水和物を添加することが有効であることを見出した。 Tetra n-butylammonium bromide hydrate forms clathrate hydrate, its harmonic melting point is approximately 12 ° C., and the latent heat at this harmonic melting point is 178 J / g. Considering the composition of heat storage agent with anti-cooling effect with tetra nbutylammonium bromide hydrate as the main component of heat storage agent, found that it is effective to add tetra nbutylammonium fluoride hydrate. It was.
弗化テトラｎブチルアンモニウム水和物は調和融点が２５℃であり、臭化テトラｎブチルアンモニウム水和物からなる蓄熱剤主成分の融点１２℃より十分に高いため、蓄熱剤主成分に添加して冷却すると、先に弗化テトラｎブチルアンモニウム水和物を形成して蓄熱剤主成分の水和物形成の核になり、蓄熱剤主成分の水和物が短時間で生成されるので、過冷却を有効に防止することができる。また、弗化テトラｎブチルアンモニウム水和物は蓄熱剤主成分の類縁物質であるので、蓄熱剤主成分との相溶性もあり、結晶構造なども類似しているため、効果的に過冷却を防止することができる。 Tetra nbutylammonium fluoride hydrate has a harmonic melting point of 25 ° C and is sufficiently higher than the melting point of 12 ° C of the main component of the heat storage agent composed of tetra nbutylammonium bromide hydrate. When cooled in this way, tetra nbutylammonium fluoride hydrate is first formed and becomes the core of hydrate formation of the main component of the heat storage agent, and the hydrate of the main component of the heat storage agent is generated in a short time. Supercooling can be effectively prevented. In addition, since tetra nbutylammonium fluoride hydrate is a related substance of the main component of the heat storage agent, it is compatible with the main component of the heat storage agent, and the crystal structure is similar. Can be prevented.
なお、過冷却防止剤としての弗化テトラｎブチルアンモニウム水和物の添加量に関しては、弗化テトラｎブチルアンモニウム水和物を臭化テトラｎブチルアンモニウム水和物からなる蓄熱剤主成分に対して1〜６重量％添加することが好ましく、これにより確実に過冷却を防止することができる。添加量が1％未満であると、蓄熱剤主成分の水和物生成の核となって過冷却を防止する効果が不足する。他方、添加量が６％を超えると、蓄熱剤主成分と過冷却防止剤の混合物の融点と潜熱量が影響を受け、空調向けの用途において要望される3〜16℃の温度範囲で蓄熱できる潜熱量が著しく減少するので、不具合が生じる。 Regarding the amount of tetra-n-butylammonium fluoride hydrate added as a supercooling inhibitor, tetra-n-butylammonium fluoride hydrate is added to the main component of the heat storage agent composed of tetra-n-butylammonium bromide hydrate. It is preferable to add 1 to 6% by weight, which can reliably prevent overcooling. When the addition amount is less than 1%, the effect of preventing overcooling becomes a core of hydrate formation of the main component of the heat storage agent. On the other hand, if the addition amount exceeds 6%, the melting point and latent heat amount of the mixture of the main component of the heat storage agent and the supercooling inhibitor are affected, and heat can be stored in the temperature range of 3 to 16 ° C. required for air conditioning applications. Since the amount of latent heat is significantly reduced, problems occur.
以下においては、過冷却防止剤としての弗化テトラｎブチルアンモニウム（TBAF）水和物の添加率に関して具体的に説明する。
臭化テトラｎブチルアンモニウム（TBAB）の調和融点を与える濃度（４０重量％）の水溶液からなる蓄熱剤主成分に、弗化テトラｎブチルアンモニウム（TBAF）の調和融点を与える濃度（３３重量％）の水溶液を、蓄熱剤主成分に対する添加重量比率を数水準とって添加して蓄熱剤を調製した。以下、本発明では調和融点を与える濃度の水溶液を調和水溶液という。
以下においては、臭化テトラｎブチルアンモニウム調和水溶液からなる蓄熱剤主成分に、弗化テトラｎブチルアンモニウム調和水溶液の蓄熱剤主成分に対する添加率（重量比率）を数水準とった蓄熱剤について、以下に示す過冷却防止性能評価および潜熱量計側、潜熱量比の調査、および融点計測を行った。
Hereinafter, the addition rate of tetra n-butylammonium fluoride (TBAF) hydrate as a supercooling inhibitor will be specifically described.
Concentration (33% by weight) of tetra-n-butylammonium bromide (TBAB), which gives the harmonic melting point of tetra-n-butylammonium fluoride (TBAF), to the main component of the heat storage agent consisting of an aqueous solution having a concentration (40% by weight) that gives a harmonic melting point of tetra-n-butylammonium bromide (TBAB) The heat storage agent was prepared by adding several weights of the aqueous solution of the heat storage agent to the heat storage agent main component at several levels. Hereinafter, in the present invention, an aqueous solution having a concentration that provides a harmonic melting point is referred to as a harmonic aqueous solution.
In the following, regarding the heat storage agent composed of a harmonious aqueous solution of tetra n-butylammonium bromide, the heat storage agent having several levels of addition ratio (weight ratio) of the harmonious aqueous solution of tetra n-butyl ammonium fluoride to the heat storage agent main component, The evaluation of overcooling performance and the latent calorimeter side, the investigation of the latent heat amount ratio, and the melting point measurement were performed.
・過冷却防止性能の評価
調製した蓄熱剤の溶液を３℃に冷却し、水和物の結晶が生成し過冷却が解除されるまでの時間を計測し、５分以内に水和物結晶が生成すれば過冷却防止性能が認められると評価した。さらに、蓄熱剤を３℃に冷却して水和物を生成させ、その後４０℃に加熱して生成した水和物を融解させるという凝固融解を1000回繰返して、過冷却防止性能の低下がないと認められたときに過冷却防止性能の耐久性があると評価した。
・潜熱量計測、潜熱量比の調査、および融点計測
調製した蓄熱剤のDSC（差動走査型熱量計）測定を実施し潜熱量と融点を測定した。潜熱量は空調向けの用途において要望される3〜16℃の温度範囲で融解時の熱量を計測して求めた。また、弗化テトラｎブチルアンモニウム調和水溶液を添加しないものの潜熱量を１として、潜熱量比を求め潜熱量の変化を評価した。また、横軸に温度、縦軸に比熱をとったグラフのピークを示す温度を融点として、融点を計測した。そして、過冷却防止性に優れて、かつ、空調向けの用途において要望される3〜16℃の温度範囲の潜熱量の低下が少ない弗化テトラｎブチルアンモニウム調和水溶液の好適な添加率を求めた。
・ Evaluation of anti-cooling performance The prepared heat storage agent solution is cooled to 3 ° C., and the time until the hydrate crystals are formed and the supercooling is released is measured. It was evaluated that supercooling prevention performance was recognized if produced. Furthermore, the heat storage agent is cooled to 3 ° C. to produce a hydrate, and then heated to 40 ° C. to melt the produced hydrate 1000 times, so that the overcooling prevention performance does not deteriorate. When it was recognized, it was evaluated that it had durability of the supercooling prevention performance.
・ Latent heat quantity measurement, latent heat quantity ratio investigation, and melting point measurement The DSC (differential scanning calorimeter) measurement of the prepared heat storage agent was carried out to measure the latent heat quantity and the melting point. The amount of latent heat was obtained by measuring the amount of heat at the time of melting in the temperature range of 3 to 16 ° C. required in applications for air conditioning. In addition, the latent heat amount of the solution to which the tetra nbutylammonium fluoride aqueous solution was not added was set to 1, and the latent heat amount ratio was obtained to evaluate the change in the latent heat amount. Further, the melting point was measured with the temperature indicating the peak of the graph having the temperature on the horizontal axis and the specific heat on the vertical axis as the melting point. And the suitable addition rate of the tetra-n-butylammonium fluoride harmony aqueous solution which is excellent in supercooling prevention property and has little fall of the amount of latent heat of the temperature range of 3-16 degreeC requested | required in the use for air conditioning was calculated | required. .
臭化テトラｎブチルアンモニウム調和水溶液からなる蓄熱剤主成分に弗化テトラｎブチルアンモニウム調和水溶液の蓄熱剤主成分に対する添加率（重量比率、TBAF添加率という）を数水準変えて添加し、評価した結果を表１に示す。 The addition ratio (weight ratio, TBAF addition ratio) of tetra nbutylammonium fluoride harmonized aqueous solution to heat storage agent main component consisting of harmonized aqueous solution of tetra nbutylammonium bromide was added and evaluated. The results are shown in Table 1.
表１においては、過冷却防止性能があり、1000回の凝固融解繰返し後も過冷却防止性能の低下がない場合には○を記載し、過冷却防止性能の低下があった場合には×を記載している。
表１から、過冷却防止性能は、弗化テトラｎブチルアンモニウム調和水溶液の添加率が１重量％を下回ると不十分であることが判明した。
また、潜熱量比は、弗化テトラｎブチルアンモニウム調和水溶液の添加率が６重量％を超えると大きく減少することが判明した。このように弗化テトラｎブチルアンモニウム調和水溶液の添加率が、ある値になったときから3〜16℃の温度範囲の潜熱量が急減することは予見できない結果であった。
In Table 1, when there is a supercooling prevention performance and there is no decrease in the supercooling prevention performance even after 1000 times of solidification and melting, ○ is indicated, and when there is a reduction in the supercooling prevention performance, × is indicated. It is described.
From Table 1, it was found that the supercooling prevention performance was insufficient when the addition ratio of the tetra nbutylammonium fluoride harmonized aqueous solution was less than 1% by weight.
It was also found that the latent heat ratio is greatly reduced when the addition ratio of the tetra-n-butylammonium fluoride harmonized aqueous solution exceeds 6% by weight. Thus, it was an unpredictable result that the amount of latent heat in the temperature range of 3 to 16 ° C. suddenly decreased after the addition rate of the tetra-n-butylammonium fluoride harmonized aqueous solution reached a certain value.
潜熱量が減少する理由について検討した。
DSC測定結果を、横軸に温度、縦軸に潜熱量をとってグラフ化したものを図１に示す。図１において点線で示すＡが臭化テトラｎブチルアンモニウム調和水溶液に弗化テトラｎブチルアンモニウム調和水溶液を添加しない場合、実線で示すＢが臭化テトラｎブチルアンモニウム調和水溶液に弗化テトラｎブチルアンモニウム調和水溶液を９重量％添加した場合である。弗化テトラｎブチルアンモニウム調和水溶液を９％添加した場合には、潜熱を持つ範囲が弗化テトラｎブチルアンモニウム調和水溶液を添加しない場合よりも高温側に移動していることが認められる。そのため、空調用蓄熱剤として要望される3〜16℃の温度範囲の潜熱量が減少しており、これが3〜16℃の温度範囲の潜熱量が減少する理由である。なお、潜熱をもつ範囲が高温側に移動するのに伴い融点も高温側に移動する。
The reason why the amount of latent heat is reduced was examined.
FIG. 1 shows a graph of DSC measurement results, with the horizontal axis representing temperature and the vertical axis representing latent heat. In FIG. 1, when A indicated by a dotted line does not add a tetra nbutylammonium bromide harmonic aqueous solution to the tetra nbutylammonium bromide harmonic aqueous solution, B indicated by a solid line indicates a tetra nbutylammonium fluoride harmonic aqueous solution. This is the case where 9% by weight of the conditioned aqueous solution is added. It can be seen that when 9% of the tetra nbutylammonium fluoride aqueous solution is added, the range with latent heat is shifted to a higher temperature side than when no tetranbutylammonium fluoride aqueous solution is added. For this reason, the amount of latent heat in the temperature range of 3 to 16 ° C., which is desired as a heat storage agent for air conditioning, is decreased, which is the reason for the decrease in the amount of latent heat in the temperature range of 3 to 16 ° C. As the range with latent heat moves to the high temperature side, the melting point also moves to the high temperature side.
以上の結果から、凝固融解繰返し後も過冷却防止性能の低下がないように過冷却防止性が優れて、かつ、3〜16℃の温度範囲の潜熱量の低下がないか、またはあったとしても低下が１０％より少ないような弗化テトラｎブチルアンモニウム調和水溶液の好ましい添加率は、１〜６重量％であると認められる。
つまり、臭化テトラｎブチルアンモニウム調和水溶液からなる蓄熱剤主成分に添加する弗化テトラｎブチルアンモニウム調和水溶液の添加率は、蓄熱剤主成分に対して１〜６重量％が好適である。
From the above results, it is said that the supercooling prevention performance is excellent so that the supercooling prevention performance does not deteriorate even after repeated solidification and melting, and the latent heat amount in the temperature range of 3 to 16 ° C. is not reduced. It is recognized that the preferable addition rate of the aqueous solution of tetra-n-butylammonium fluoride in which the decrease is less than 10% is 1 to 6% by weight.
That is, the addition ratio of the tetra nbutylammonium fluoride harmonized aqueous solution composed of the tetra nbutylammonium bromide harmonized aqueous solution is preferably 1 to 6% by weight with respect to the heat storant major component.
上記の弗化テトラｎブチルアンモニウムの過冷却防止性を評価した場合には、弗化テトラｎブチルアンモニウムの調和水溶液を蓄熱剤主成分に添加して検討したが、弗化テトラｎブチルアンモニウム三水和物の粉末を蓄熱剤主成分に添加しても、同様に過冷却防止性があり、凝固融解を1000回繰返しても過冷却防止性能の低下がないことを確認した。 When the above-described anti-cooling property of tetra nbutylammonium fluoride was evaluated, a harmonized aqueous solution of tetra nbutylammonium fluoride was added to the heat storage agent main component. It was confirmed that even when a Japanese powder was added to the main component of the heat storage agent, it was similarly capable of preventing supercooling, and even when the solidification and melting were repeated 1000 times, there was no decrease in the supercooling prevention performance.
また、上記の弗化テトラｎブチルアンモニウム水和物の好適な添加率を求める検討では、臭化テトラｎブチルアンモニウムの調和融点を与える濃度（調和濃度という）の水溶液を用いて検討したが、調和濃度の水溶液に限らず調和濃度より小さい濃度又は大きい濃度の水溶液でも、同様の傾向があり、弗化テトラｎブチルアンモニウム水和物の添加率は臭化テトラｎブチルアンモニウム水和物からなる蓄熱剤主成分に対して１〜６重量％が好適である。もっとも、調和濃度の水溶液の場合には潜熱量が最大となるため好ましい。なお、調和濃度より小さい濃度又は大きい濃度の水溶液を用いると、融点を調和融点より低くすることができる。 In addition, in the study for obtaining a suitable addition rate of the above-mentioned tetra nbutylammonium fluoride hydrate, an aqueous solution having a concentration (referred to as a harmonic concentration) that gives a harmonic melting point of tetra nbutylammonium bromide was used. There is a similar tendency not only in aqueous solution of concentration but also in aqueous solution of lower concentration or higher concentration, and the addition rate of tetra nbutylammonium fluoride hydrate is a heat storage agent comprising tetra nbutylammonium bromide hydrate 1-6 weight% is suitable with respect to a main component. However, an aqueous solution having a harmonic concentration is preferable because the amount of latent heat is maximized. If an aqueous solution having a concentration lower than or higher than the harmonic concentration is used, the melting point can be made lower than the harmonic melting point.
また、上記の検討では、過冷却防止剤として添加する弗化テトラｎブチルアンモニウムは、調和濃度の水溶液を用いて検討したが、調和濃度の水溶液に限らず調和濃度より小さい濃度又は大きい濃度の水溶液でも同様の効果がある。調和濃度の水溶液の場合には潜熱量が最大となるため、弗化テトラｎブチルアンモニウムを添加した蓄熱剤全体として潜熱量が最大となるので好ましい。 Further, in the above study, tetra n-butylammonium fluoride added as a supercooling inhibitor was studied using an aqueous solution having a harmonic concentration. However, the aqueous solution having a concentration lower than or higher than the harmonic concentration is not limited to an aqueous solution having a harmonic concentration. But it has the same effect. In the case of an aqueous solution having a harmonic concentration, the amount of latent heat is maximized, and therefore the amount of latent heat is maximized for the entire heat storage agent to which tetra-n-butylammonium fluoride is added.
また、弗化テトラｎブチルアンモニウムに代えてリン酸水素二ナトリウムを過冷却防止剤として添加しても効果的に過冷却を防止することができる。そして、弗化テトラｎブチルアンモニウムとリン酸水素二ナトリウムを過冷却防止剤として併用して添加すれば、さらに効果的に過冷却を防止することができる。
リン酸水素二ナトリウムを臭化テトラｎブチルアンモニウム水和物からなる蓄熱剤主成分に対して0.1〜2重量％添加し、弗化テトラｎブチルアンモニウムも添加するように併用すると、弗化テトラｎブチルアンモニウムだけを添加した場合よりも過冷却防止性能が向上するため、過冷却防止のために添加する弗化テトラｎブチルアンモニウムの最低添加率を低減することができる。これにより弗化テトラｎブチルアンモニウムを添加することによる蓄熱剤の潜熱量の変化を小さく抑えることできる。
Further, even if disodium hydrogen phosphate is added as a supercooling inhibitor in place of tetra-n-butylammonium fluoride, supercooling can be effectively prevented. Then, if tetra nbutylammonium fluoride and disodium hydrogen phosphate are added in combination as a supercooling inhibitor, supercooling can be prevented more effectively.
When disodium hydrogen phosphate is added in an amount of 0.1 to 2% by weight based on the main component of the heat storage agent composed of tetra-n-butylammonium bromide hydrate and tetra-n-butylammonium fluoride is also added, Since the overcooling prevention performance is improved as compared with the case where only butylammonium is added, the minimum addition rate of tetra-n-butylammonium fluoride added for preventing overcooling can be reduced. Thereby, the change of the amount of latent heat of a thermal storage agent by adding tetra n butyl ammonium fluoride can be suppressed small.
また、蓄熱剤成分としてさらに腐食抑制剤を添加することにより、腐食を抑制することができる。腐食抑制剤としては、例えば亜硫酸塩またはチオ硫酸塩のナトリウム塩、リチウム塩が挙げられ、蓄熱剤に添加して溶存する酸素を消費して腐食を抑制することができる（脱酸型腐食抑制剤という）。
また、他の腐食抑制剤としては、ポリリン酸塩、トリポリリン酸塩、テトラポリリン酸塩、燐酸水素二塩、ピロ燐酸塩またはメタ珪酸塩のナトリウム塩、カリウム塩、カルシウム塩、リチウム塩が挙げられ、金属表面に腐食を防止する被膜を形成して腐食を抑制することができる（被膜形成型腐食抑制剤という）。これらの被膜形成型腐食抑制剤と前述した脱酸型腐食抑制剤の亜硫酸塩またはチオ硫酸塩を併用することにより、さらに腐食を抑制することができる。
さらに、他の腐食抑制剤として亜硝酸塩、ベンゾトリアゾール、ヒドラジン、エリソルビン酸塩、アスコルビン酸塩、糖類が挙げられる。
上記の腐食抑制剤を蓄熱剤に添加することにより、融点や蓄熱量を大きく変えずに腐食性の少ない蓄熱剤を提供することができる。
Moreover, corrosion can be suppressed by adding a corrosion inhibitor further as a heat storage agent component. Examples of the corrosion inhibitor include sodium salt and lithium salt of sulfite or thiosulfate, which can be added to the heat storage agent to consume dissolved oxygen and suppress corrosion (deoxidation type corrosion inhibitor). Called).
Other corrosion inhibitors include polyphosphate, tripolyphosphate, tetrapolyphosphate, dihydrogen phosphate, pyrophosphate or metasilicate sodium salt, potassium salt, calcium salt, lithium salt. It is possible to suppress corrosion by forming a coating that prevents corrosion on the metal surface (referred to as a coating-forming type corrosion inhibitor). Corrosion can be further suppressed by using these film-forming corrosion inhibitors in combination with the above-described deoxidizing corrosion inhibitor sulfites or thiosulfates.
Further, other corrosion inhibitors include nitrite, benzotriazole, hydrazine, erythorbate, ascorbate, and saccharide.
By adding the above-described corrosion inhibitor to the heat storage agent, it is possible to provide a heat storage agent with less corrosivity without greatly changing the melting point and the heat storage amount.
本発明に係る蓄熱剤は、臭化テトラｎブチルアンモニウム水和物からなる蓄熱剤主成分と、蓄熱剤主成分に対して１〜６重量％の弗化テトラｎブチルアンモニウム水和物を含有してなることから、空調向けの用途において要望される3〜16℃の温度範囲で多くの冷熱を蓄熱でき、過冷却防止効能が高く、また水和物の凝固と融解を頻繁に繰返しても過冷却防止効能を維持できる。 The heat storage agent according to the present invention contains a heat storage agent main component composed of tetra nbutylammonium bromide hydrate and 1 to 6% by weight of tetra nbutylammonium fluoride hydrate based on the heat storage agent main component. Therefore, it can store a large amount of cold in the temperature range of 3 to 16 ° C, which is required for air conditioning applications, has a high anti-cooling effect, and does not exceed the hydrate solidification and melting frequently. Anti-cooling effect can be maintained.
以下においては、本発明の実施例を示し、その過冷却防止性能を評価し、潜熱量の変化を調査した。
臭化テトラｎブチルアンモニウム（TBAB）の調和水溶液からなる蓄熱剤主成分に、弗化テトラｎブチルアンモニウム（TBAF）の調和水溶液を蓄熱剤主成分に対して３重量％添加して蓄熱剤を調製した。
In the following, examples of the present invention were shown, their supercooling prevention performance was evaluated, and changes in latent heat amount were investigated.
Prepare a heat storage agent by adding 3% by weight of a harmonious aqueous solution of tetra-n-butylammonium fluoride (TBAF) to the heat storage agent main component consisting of a harmonious aqueous solution of tetra-n-butylammonium bromide (TBAB). did.
調製した蓄熱剤の溶液を３℃に冷却し、水和物の結晶が生成し過冷却が解除されるまでの時間を計測したところ、５分程度以内に水和物結晶が生成し過冷却が防止された。この水和物結晶は1箇所だけでなく数箇所から生成し、それぞれの水和物結晶が10mm程度にまで成長するのに要した時間は、約5分間であり、短時間に水和物結晶が生成し成長することが確認できた。
さらに、蓄熱剤を３℃に冷却し水和物を生成させ、４０℃に加熱し生成した水和物を融解させる凝固融解を1000回繰返して、過冷却防止性能の変化を調べたところ、過冷却防止性能の低下がないと認められた。
また、この蓄熱剤の3〜16℃の温度範囲の潜熱量は174J/gであり、弗化テトラｎブチルアンモニウム調和水溶液を添加しない蓄熱剤主成分の潜熱量178J/gに比べて低下が２％であり、潜熱量の低下がほとんどないと認められた。
The prepared solution of the heat storage agent was cooled to 3 ° C., and the time until the hydrate crystals were formed and the supercooling was released was measured. Prevented. These hydrate crystals are generated not only from one place but from several places. The time required for each hydrate crystal to grow to about 10 mm is about 5 minutes. Was generated and grown.
Furthermore, when the heat storage agent was cooled to 3 ° C to form a hydrate, and heated to 40 ° C to solidify and melt the melted hydrate 1000 times, the change in the supercooling prevention performance was examined. It was recognized that there was no decrease in cooling prevention performance.
In addition, the latent heat amount in the temperature range of 3 to 16 ° C. of this heat storage agent is 174 J / g, which is 2% lower than the latent heat amount 178 J / g of the main component of the heat storage agent to which no aqueous solution of tetra-n-butylammonium fluoride is added. %, And it was recognized that there was almost no decrease in latent heat.
このように臭化テトラｎブチルアンモニウム調和水溶液からなる蓄熱剤主成分に対して、弗化テトラｎブチルアンモニウム調和水溶液を３重量％添加することにより、水和物結晶を短時間で生成でき、凝固融解を1000回繰返しても過冷却防止性能の低下がなく、3〜16℃の温度範囲の潜熱量の低下が少ない蓄熱剤を提供できることが確認できた。 Thus, by adding 3% by weight of tetra nbutylammonium fluoride aqueous solution to the main component of the heat storage agent consisting of the aqueous solution of tetra nbutylammonium bromide, hydrate crystals can be formed in a short time and solidified. It was confirmed that even when the melting was repeated 1000 times, there was no decrease in the supercooling prevention performance, and it was possible to provide a heat storage agent with a small decrease in the amount of latent heat in the temperature range of 3 to 16 ° C.
上記実施例の効果を確認するために、以下に示す比較実験を行った。
（ａ）比較例１
弗化テトラｎブチルアンモニウム添加の効果を確認するために、臭化テトラｎブチルアンモニウム調和水溶液のみの蓄熱剤を調製した。調製した蓄熱剤を３℃に冷却したところ、２４時間経過しても水和物の結晶が生成せず過冷却状態が続いた。
これに対して、弗化テトラｎブチルアンモニウムを添加した上述の実施例では５分程度以内に水和物結晶が生成し過冷却が防止されていることから、弗化テトラｎブチルアンモニウムが過冷却防止機能を発揮していることが分かる。
In order to confirm the effects of the above examples, the following comparative experiment was performed.
(A) Comparative Example 1
In order to confirm the effect of addition of tetra-n-butylammonium fluoride, a heat storage agent containing only a tetra-n-butylammonium bromide harmonized aqueous solution was prepared. When the prepared heat storage agent was cooled to 3 ° C., hydrate crystals did not form even after 24 hours, and the supercooled state continued.
On the other hand, in the above-mentioned embodiment in which tetra-n-butylammonium fluoride was added, hydrate crystals were formed within about 5 minutes and supercooling was prevented. It turns out that the prevention function is demonstrated.
（ｂ）比較例２
次に上記実施例においては弗化テトラｎブチルアンモニウムの調和水溶液を蓄熱剤主成分に対して３重量％添加したが、この添加量と添加方法の効果を確認するために以下の比較実験を行った。
臭化テトラｎブチルアンモニウムの調和水溶液のみの蓄熱剤を調製した。一方、弗化テトラｎブチルアンモニウムの調和水溶液を多孔質体である活性炭粒子に含浸させた。前記臭化テトラｎブチルアンモニウム調和水溶液のみの蓄熱剤に、前記の弗化テトラｎブチルアンモニウム調和水溶液を含浸した活性炭粒子を数粒添加して３℃に冷却した。臭化テトラｎブチルアンモニウムの調和水溶液のみの蓄熱剤に対する弗化テトラｎブチルアンモニウム調和水溶液の添加量は約0.1重量％に相当する。
(B) Comparative Example 2
Next, in the above examples, 3% by weight of a conc. Aqueous solution of tetra-n-butylammonium fluoride was added to the main component of the heat storage agent. In order to confirm the effect of this addition amount and addition method, the following comparative experiment was conducted. It was.
A heat storage agent containing only a conc. Aqueous solution of tetra-n-butylammonium bromide was prepared. On the other hand, activated carbon particles, which are porous bodies, were impregnated with a harmonic aqueous solution of tetra-n-butylammonium fluoride. Several activated carbon particles impregnated with the tetra nbutylammonium fluoride harmonized aqueous solution were added to the heat storage agent containing only the tetra nbutylammonium bromide harmonized aqueous solution and cooled to 3 ° C. The amount of tetra nbutylammonium bromide harmonized aqueous solution added to the heat storage agent of only the conditioned aqueous solution of tetra nbutylammonium bromide corresponds to about 0.1% by weight.
冷却開始から数分後に活性炭粒子の周辺から水和物結晶が生成し過冷却が解除された。また、水和物結晶が10mm程度にまで成長するのに要した時間は、約10分程度であった。さらに、蓄熱剤を３℃に冷却し水和物を生成させ、４０℃に加熱し生成した水和物を融解させる凝固融解を繰返して、過冷却防止性能の変化を調べたところ、凝固融解の繰返し５回目で水和物結晶が生成しなくなった。
この比較例から、過冷却解除効果は認められるものの、水和物結晶が10mm程度にまで成長するのに要した時間は実施例の場合の２倍を要している。凝固融解の繰返し５回目で水和物結晶が生成しなくなったことから、弗化テトラｎブチルアンモニウムの調和水溶液を多孔質体である活性炭粒子に含浸させる方法では、凝固融解の繰返しによる過冷却防止性能の低下が著しく問題がある。
A few minutes after the start of cooling, hydrate crystals were formed around the activated carbon particles, and the supercooling was released. The time required for the hydrate crystals to grow to about 10 mm was about 10 minutes. Furthermore, the heat storage agent was cooled to 3 ° C. to form a hydrate, and heated to 40 ° C. to repeat the solidification and melting to melt the produced hydrate. Hydrate crystals no longer formed after the fifth repetition.
Although the supercooling release effect is recognized from this comparative example, the time required for the hydrate crystals to grow to about 10 mm requires twice as much as in the case of the example. Since hydrate crystals are no longer formed at the fifth repetition of solidification and melting, the method of impregnating activated carbon particles, which are porous n-butylammonium fluoride, into porous activated carbon particles prevents overcooling by repeated solidification and melting. There is a significant problem in performance degradation.
（ｃ）比較例３
比較例２の多孔質体の活性炭粒子をアルミナ多孔質体に代えて、同様に過冷却防止性能の評価した。水和物結晶が10mm程度にまで成長するのに要した時間は、約10分程度と比較例２と同程度であり、凝固融解の繰返し20回目で水和物結晶が生成しなくなった。
この場合も凝固融解の繰返しによる過冷却防止性能の低下が著しく問題がある。
(C) Comparative Example 3
The activated carbon particles of the porous body of Comparative Example 2 were replaced with an alumina porous body, and the supercooling prevention performance was similarly evaluated. The time required for the hydrate crystals to grow to about 10 mm was about 10 minutes, which was the same as that of Comparative Example 2, and no hydrate crystals were formed after the 20th repetition of solidification and melting.
Also in this case, there is a significant problem that the overcooling prevention performance is lowered due to repeated solidification and melting.
＜腐食抑制剤について＞
臭化テトラｎブチルアンモニウムの調和水溶液からなる蓄熱剤主成分に、弗化テトラｎブチルアンモニウムの調和水溶液を添加した蓄熱剤（以下調製蓄熱剤という）は、臭素イオンと弗素イオンを含むため炭素鋼やアルミニウムに対して腐食性があるので、腐食抑制剤を添加して腐食を抑制することが好ましい。
腐食抑制剤としては、例えば亜硫酸塩、チオ硫酸塩のナトリウム塩、リチウム塩が挙げられ、蓄熱剤に添加して溶存する酸素を消費して腐食を抑制することができる（脱酸型腐食抑制剤という）。
<About corrosion inhibitors>
A heat storage agent (hereinafter referred to as “preparation heat storage agent”) in which a harmonic aqueous solution of tetra nbutylammonium fluoride is added to a main component of a heat storage agent composed of a harmonic aqueous solution of tetra-n-butylammonium bromide is a carbon steel because it contains bromine ions and fluorine ions. Since it is corrosive to aluminum and aluminum, it is preferable to suppress corrosion by adding a corrosion inhibitor.
Examples of the corrosion inhibitor include sulfite, sodium salt of thiosulfate, and lithium salt, and can be added to the heat storage agent to consume dissolved oxygen and suppress corrosion (deoxidation type corrosion inhibitor). Called).
また、他の腐食抑制剤としては、ポリリン酸塩、トリポリリン酸塩、テトラポリリン酸塩、燐酸水素二塩、ピロ燐酸塩またはメタ珪酸塩のナトリウム塩、カリウム塩、カルシウム塩、リチウム塩が挙げられ、金属表面に腐食を防止する被膜を形成して腐食を抑制することができる（被膜形成型腐食抑制剤という）。これらの被膜形成型腐食抑制剤と前述した脱酸型腐食抑制剤の亜硫酸塩またはチオ硫酸塩を併用することにより、さらに腐食を抑制することができる。
さらに、他の腐食抑制剤として亜硝酸塩、ベンゾトリアゾール、ヒドラジン、エリソルビン酸塩、アスコルビン酸塩、糖類が挙げられる。
上記の腐食抑制剤を添加することにより、融点や蓄熱量を大きく変えずに腐食性の少ない蓄熱剤を提供することができる。
Other corrosion inhibitors include polyphosphate, tripolyphosphate, tetrapolyphosphate, dihydrogen phosphate, pyrophosphate or metasilicate sodium salt, potassium salt, calcium salt, lithium salt. It is possible to suppress corrosion by forming a coating that prevents corrosion on the metal surface (referred to as a coating-forming type corrosion inhibitor). Corrosion can be further suppressed by using these film-forming corrosion inhibitors in combination with the above-described deoxidizing corrosion inhibitor sulfites or thiosulfates.
Further, other corrosion inhibitors include nitrite, benzotriazole, hydrazine, erythorbate, ascorbate, and saccharide.
By adding the above-described corrosion inhibitor, it is possible to provide a heat storage agent with less corrosivity without greatly changing the melting point and the amount of heat storage.
臭化テトラｎブチルアンモニウムの調和水溶液からなる蓄熱剤主成分に、弗化テトラｎブチルアンモニウムの調和水溶液を３重量％添加した調製蓄熱剤に腐食抑制剤を添加して腐食抑制効果について評価した。
調製蓄熱剤に、表２に示すように腐食抑制剤を添加して、炭素鋼板とアルミニウム板を浸漬し90℃にて1週間保持したのち、重量減少量を測定して腐食速度を求め、結果を表２に示す。
The corrosion inhibitor was evaluated by adding a corrosion inhibitor to a prepared heat storage agent in which 3% by weight of a harmonic aqueous solution of tetra-n-butylammonium fluoride was added to the main component of the thermal storage agent consisting of a harmonic aqueous solution of tetra-n-butylammonium bromide.
Add the corrosion inhibitor as shown in Table 2 to the prepared heat storage agent, immerse the carbon steel plate and aluminum plate and hold at 90 ° C for 1 week, then measure the weight loss and determine the corrosion rate. Is shown in Table 2.
表２の（１）に示すように、亜硫酸ナトリウムを添加することにより、腐食抑制剤を添加しない場合（４）に対して炭素鋼では腐食速度が0.56mm/年から0.09mm/年になっており、またアルミニウムでは腐食速度が0.26mm/年から0.05mm/年になっており、いずれの場合にも腐食速度を数分の１以下に抑制でき、腐食抑制効果が認められる。
また、ポリリン酸ナトリウムを添加した場合（２）にも、腐食抑制剤を添加しない場合（４）に対して炭素鋼では腐食速度が0.56mm/年から0.12mm/年になっており、またアルミニウムでは腐食速度が0.26mm/年から0.02mm/年になっており、いずれの場合にも亜硫酸ナトリウムを添加の場合と同様に腐食速度を数分の１以下に抑制でき、腐食抑制効果が認められる。
さらに、亜硫酸ナトリウムとポリリン酸ナトリウムを併用した場合（３）には、腐食抑制剤を添加しない場合（４）に対して炭素鋼では腐食速度が0.56mm/年から0.05mm/年になっており、またアルミニウムでは腐食速度が0.26mm/年から0mm/年になっており、いずれの場合にも各腐食抑制剤を単独で用いたときよりも高い腐食抑制効果が認められる。
なお、上述した他の腐食抑制剤でも同様に腐食を十分に抑制できる効果があることを確認している。
As shown in (2) of Table 2, by adding sodium sulfite, the corrosion rate of carbon steel is reduced from 0.56mm / year to 0.09mm / year when no corrosion inhibitor is added (4). In addition, the corrosion rate of aluminum is 0.26 mm / year to 0.05 mm / year. In either case, the corrosion rate can be suppressed to a fraction or less, and a corrosion inhibiting effect is recognized.
Also, when sodium polyphosphate is added (2) and when no corrosion inhibitor is added (4), the corrosion rate of carbon steel is 0.56mm / year to 0.12mm / year, and aluminum Has a corrosion rate of 0.26 mm / year to 0.02 mm / year, and in both cases, the corrosion rate can be reduced to a fraction of the same value as when sodium sulfite is added, and a corrosion inhibiting effect is recognized. .
Furthermore, when sodium sulfite and sodium polyphosphate are used in combination (3), the corrosion rate of carbon steel is 0.56mm / year to 0.05mm / year when no corrosion inhibitor is added (4). Moreover, the corrosion rate of aluminum is 0.26 mm / year to 0 mm / year, and in each case, a higher corrosion inhibitory effect is observed than when each corrosion inhibitor is used alone.
In addition, it has been confirmed that the other corrosion inhibitors described above have the effect of sufficiently suppressing corrosion.
＜蓄熱剤の調製方法＞
臭化テトラｎブチルアンモニウムの調和濃度、調和濃度より小さい濃度または調和濃度より大きい濃度の水溶液からなる蓄熱剤主成分に、蓄熱剤主成分に対して１〜６重量％の弗化テトラｎブチルアンモニウムの調和濃度、調和濃度より小さい濃度または調和濃度より大きい濃度の水溶液を添加して蓄熱剤を調製する。
このように調製することにより、過冷却防止性が優れて、かつ、3〜16℃の温度範囲の潜熱量の低下が少ない蓄熱剤を得ることができる。
<Method for preparing heat storage agent>
1 to 6% by weight of tetra-n-butylammonium fluoride based on the heat storage agent main component comprising an aqueous solution of tetra-n-butylammonium bromide harmonic concentration, concentration lower than harmonic concentration or concentration higher than harmonic concentration A heat storage agent is prepared by adding an aqueous solution having a concentration of less than, less than or greater than the harmonic concentration.
By preparing in this way, it is possible to obtain a heat storage agent that is excellent in supercooling prevention properties and has little decrease in latent heat in the temperature range of 3 to 16 ° C.
臭化テトラｎブチルアンモニウムの水溶液が調和濃度の水溶液の場合には潜熱量が最大となるため好ましい。なお、調和濃度より小さい濃度又は大きい濃度の水溶液を用いると、融点を調和融点より低くすることができる。
また、過冷却防止剤として添加する弗化テトラｎブチルアンモニウムは、調和濃度の水溶液に限らず調和濃度より小さい濃度又は大きい濃度の水溶液でも同様の効果がある。もっとも、調和濃度の水溶液の場合には潜熱量が最大となるため、弗化テトラｎブチルアンモニウムを添加した蓄熱剤全体として潜熱量が最大となるので好ましい。
When the aqueous solution of tetra-n-butylammonium bromide is an aqueous solution having a harmonic concentration, the amount of latent heat is maximized, which is preferable. If an aqueous solution having a concentration lower than or higher than the harmonic concentration is used, the melting point can be made lower than the harmonic melting point.
Further, tetra-n-butylammonium fluoride added as a supercooling preventive agent is not limited to an aqueous solution having a harmonic concentration, and has the same effect even in an aqueous solution having a concentration lower or higher than the harmonic concentration. However, in the case of an aqueous solution having a harmonic concentration, the amount of latent heat is maximized, and therefore the amount of latent heat is maximized for the entire heat storage agent to which tetra-n-butylammonium fluoride is added.
また、過冷却防止剤として添加する弗化テトラｎブチルアンモニウムは水溶液に限らず、弗化テトラｎブチルアンモニウム三水和物の粉末を添加して蓄熱剤を調製してもよい。
また、リン酸水素二ナトリウムを過冷却防止剤として添加しても効果的に過冷却を防止することができ、弗化テトラｎブチルアンモニウムとリン酸水素二ナトリウムを過冷却防止剤として併用して添加して、さらに効果的に過冷却を防止することができる。
リン酸水素二ナトリウムを蓄熱剤主成分に対して0.1〜2重量％添加し、弗化テトラｎブチルアンモニウムと併用すると、弗化テトラｎブチルアンモニウムだけを添加した場合よりも過冷却防止性能が向上するため、過冷却防止のために添加する弗化テトラｎブチルアンモニウムの最低添加率を低減することができる。これにより弗化テトラｎブチルアンモニウムを添加することによる蓄熱剤の潜熱量の変化を小さく抑えることできる。
The tetra-n-butylammonium fluoride added as a supercooling inhibitor is not limited to an aqueous solution, and a heat storage agent may be prepared by adding a powder of tetra-n-butylammonium fluoride trihydrate.
Moreover, even when disodium hydrogen phosphate is added as a supercooling inhibitor, supercooling can be effectively prevented, and tetra-n-butylammonium fluoride and disodium hydrogenphosphate are used in combination as supercooling inhibitors. By adding, it is possible to prevent overcooling more effectively.
Addition of 0.1-2% by weight of disodium hydrogen phosphate with respect to the main component of the heat storage agent and combined use with tetra-n-butylammonium fluoride improves the anti-cooling performance compared with the addition of tetra-n-butylammonium fluoride alone Therefore, the minimum addition rate of tetra n-butylammonium fluoride added to prevent overcooling can be reduced. Thereby, the change of the amount of latent heat of a thermal storage agent by adding tetra n butyl ammonium fluoride can be suppressed small.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2007277443A (en) * | 2006-04-10 | 2007-10-25 | Jfe Engineering Kk | Heat storage agent and heat storage solution |
| WO2008108308A1 (en) * | 2007-03-02 | 2008-09-12 | Jfe Engineering Corporation | Latent heat storage substance, inclusion hydrate or slurry thereof, method for producing inclusion hydrate or slurry thereof, and latent heat storage agent |
| JP2009161719A (en) * | 2007-12-10 | 2009-07-23 | Jfe Engineering Corp | Heat storage method and supercooling-suppressing method and heat storage apparatus |
| US7875749B2 (en) | 2007-03-06 | 2011-01-25 | Jfe Engineering Corporation | Clathrate hydrate containing quaternary ammonium salt as guest compound |
| EP2927299A3 (en) * | 2014-04-02 | 2015-12-23 | Panasonic Intellectual Property Management Co., Ltd. | Heat storage apparatus, method for storing heat, and method for producing heat storage apparatus |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009079159A (en) * | 2007-09-26 | 2009-04-16 | Jfe Engineering Kk | Aqueous solution for forming clathrate hydrate, heat storage agent, producing method of clathrate hydrate or its slurry, heat storing/radiating method, method for preparing aqueous solution for generating latent heat storage agent or its principal component |
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| JPH11264681A (en) * | 1998-03-18 | 1999-09-28 | Nkk Corp | Cold storage method and system employing inclusion hydrate and cold storage agent |
| JP2001172617A (en) * | 1999-12-20 | 2001-06-26 | Nkk Corp | TETRA-n-BUTYLAMMONIUM BROMIDE HYDRATE-BASED HEAT STORAGE MATERIAL |
| JP2005126728A (en) * | 2004-12-20 | 2005-05-19 | Jfe Engineering Kk | Cold storage method, cold storage system, cold storage agent, and method for taking out cold |
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| JPH09291272A (en) * | 1996-04-25 | 1997-11-11 | Mitsubishi Electric Corp | Heat accumulating material |
| JPH11264681A (en) * | 1998-03-18 | 1999-09-28 | Nkk Corp | Cold storage method and system employing inclusion hydrate and cold storage agent |
| JP2001172617A (en) * | 1999-12-20 | 2001-06-26 | Nkk Corp | TETRA-n-BUTYLAMMONIUM BROMIDE HYDRATE-BASED HEAT STORAGE MATERIAL |
| JP2005126728A (en) * | 2004-12-20 | 2005-05-19 | Jfe Engineering Kk | Cold storage method, cold storage system, cold storage agent, and method for taking out cold |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007277443A (en) * | 2006-04-10 | 2007-10-25 | Jfe Engineering Kk | Heat storage agent and heat storage solution |
| WO2008108308A1 (en) * | 2007-03-02 | 2008-09-12 | Jfe Engineering Corporation | Latent heat storage substance, inclusion hydrate or slurry thereof, method for producing inclusion hydrate or slurry thereof, and latent heat storage agent |
| US7875749B2 (en) | 2007-03-06 | 2011-01-25 | Jfe Engineering Corporation | Clathrate hydrate containing quaternary ammonium salt as guest compound |
| JP2009161719A (en) * | 2007-12-10 | 2009-07-23 | Jfe Engineering Corp | Heat storage method and supercooling-suppressing method and heat storage apparatus |
| EP2927299A3 (en) * | 2014-04-02 | 2015-12-23 | Panasonic Intellectual Property Management Co., Ltd. | Heat storage apparatus, method for storing heat, and method for producing heat storage apparatus |
| US10161688B2 (en) | 2014-04-02 | 2018-12-25 | Panasonic Intellectual Property Management Co., Ltd. | Heat storage apparatus, method for storing heat, and method for producing heat storage apparatus |
| US10921064B2 (en) | 2014-04-02 | 2021-02-16 | Panasonic Intellectual Property Management Co., Ltd. | Heat storage apparatus, method for storing heat, and method for producing heat storage apparatus |
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| JP4893036B2 (en) | 2012-03-07 |
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