JPH0655946B2 - Heat storage material composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [INDUSTRIAL FIELD] The present invention is made by adding an appropriate amount of a nucleating agent in the heat storage material composition composed mainly of a K ₂ HPO 4 · _{6H 2 O} for the prevention supercooling heat storage The present invention relates to a material composition.

[Prior Art] As a heat storage material composition used for heat storage / air conditioning (cooling) of low temperature exhaust heat, chemical heat pump, greenhouse heating, etc., conventionally, CaCl ₂ .6H ₂ O or Na having a freezing point near 30 ° C. ₂ SO ₄ 6H ₂ O (Glauber's salt) as a main component, and a freezing point adjusting agent added thereto to adjust the phase change point to, for example, around room temperature is used.

[Problems to be Solved by the Invention] However, the above-mentioned heat storage material composition becomes a complicated mixed system and CaC.
l 2 _· 6H 2 _O and sodium sulfate is seriously impaired latent heat originally has, latent heat that can be utilized per unit weight becomes small. Further, the heat storage material composition is often denatured during repeated solidification / melting to cause a shift in the freezing point, which is a drawback that it cannot withstand repeated use over a long period of time.

Therefore, the present inventors intend to provide a heat storage material composition which is a single component or a composition and has a large amount of latent heat at a predetermined phase change temperature and which does not cause deterioration in performance even when repeatedly used. Various studies have been repeated. Big _K 2 _HPO 4 · _6H 2 O resulting latent heat as shown in Table 1
Came to pay attention to.

That K has ₂ HPO 4 · _{6H 2 O} is 14 ° C. to the phase change point, at temperature rise, a solid melting starts at 14 ° C., the liquid state absorbs heat at the same time from the environment. On the other hand, when the temperature drops, the liquid crystallizes and generates heat to become a solid state.

However _{K 2 HPO} 4 · 6H 2 O is CaCl ₂ · 6H ₂
It has a characteristic that it is hard to crystallize as compared with O, and when it is used as a heat storage material, a remarkable supercooling phenomenon occurs and there are various problems in practical use.

That is, the supercooling phenomenon is a phenomenon in which the liquid phase substance does not change from the liquid phase to the solid phase even after passing the freezing point in the process of cooling, and solidification is started only after the freezing point is considerably lower. Therefore, the temperature at which the latent heat of solidification is to be generated, that is, the freezing point becomes unspecified, which is a fatal defect as a heat storage material for holding the specific temperature region.

The present invention was made in view of the such circumstances, and an object while taking a high latent heat characteristics of _{K 2 HPO 4 · 6H 2 O} , it is intended to solve the above problems in practical use.

[Means for Solving the Problems] The heat storage material composition of the present invention which has achieved the above object is K
The ₂ HPO ₄ · 6H ₂ O as a main component, CaCl _2, CaS, to or above nucleating agent is contained one or more selected from the group consisting of CaSiO ₃ and _Ca 2 _P 2 O as a nucleating agent for preventing supercooling ₇ , Ca ₃ (PO ₄ ) ・ 2H ₂ O, C
_{aHPO 4 · 2H 2 O, Zn} 3 (PO 4) 2 · 4H 2 O
It has a gist in that one or more kinds selected from the group consisting of are contained in combination.

[Operation] not be too through substantially about 14 ° C. The K ₂ HPO 4 · _{6H 2 O} only made from the heat storage material composition is its freezing point As you cooled from a molten state solidification, in Figure 1 As shown by the broken line, solidification abruptly starts when the temperature reaches, for example, about 10 ° C.
When vibration is applied at the time when the solidification further progresses, a part of the solid material re-melts, the temperature once rises, and then solidifies again. In this way, the progress of solidification from supercooling is unstable, and the degree of supercooling changes significantly depending on the temperature drop and the disturbance of the melt. Inevitably, the temperature control according to is inaccurate.

So for the present invention to prevent the K ₂ HPO 4 · _{6H 2 O} melt is supercooled state, it was decided to add a nucleating agent to promote crystallization. That _{K 2 HPO} 4 · 6H 2 O to e.g. CaS 2 wt% as a nucleating agent for preventing supercooling
When it was contained in a certain amount, the supercooling phenomenon was greatly alleviated as shown by the solid line in Fig. 1, and it was possible to suppress it to about 0.5 ° C.

As a supercooling prevention nucleating agent that exhibits the above functions, CaS
Other than CaCl ₂ , CaSiO ₃ and Ca ₂ P
₂ O ₇ , Ca ₃ (PO ₄ ) ・ 2H ₂ O, CaHPO ₄・
_{2H 2 O, Zn 3 (PO} 4) There are ₂ · 4H 2 O, in combination one or more of the former one or more or the former of one or more of the latter group of the group of the group of these nucleating agents the _addition, it is possible to prevent the K _{2 HPO} 4 · 6H 2 O supercooling. The amount of the nucleating agent added is not particularly limited, but in order to exert the addition effect more reliably, it is 1
It may be added in the range of up to 20%. The reason for this is that if it is less than 1%, the effect of preventing supercooling is insufficient as shown in the examples below, while if it is added in excess of 20%, no further effect can be expected. .

[Example] _K 2 nucleating agent _{HPO 4 · 6H 2 O, CaCl} 2, C
2 to 4 show the effect of suppressing supercooling when aS and CaSiO ₃ are contained alone or in combination of two or more kinds selected from these as shown in Tables 2 to 4. The experimental results are shown by the degree of supercooling when melting and solidifying were repeated using each heat storage material composition.

As shown in Fig. ₂ , when CaCl ₂ is used alone as the nucleating agent, when the addition amount is 0.5% (No. 1), the effect of suppressing supercooling is recognized, but the effect varies. Overall, the effect of addition is insufficient. On the other hand, in Nos. 2 and 3 in which the addition amount was 10% or more, a sufficient effect of suppressing supercooling could be obtained, and the same effect could be stably obtained even if the number of repetitions was increased.

As shown in FIG. 3, the nucleating agent is CaS, CaSiO.
Even in the case of ₃ (single), the same effect of suppressing supercooling as that of CaCl ₂ could be obtained. Further, the effect of suppressing supercooling when two kinds of the above nucleating agents are used in combination is as shown in FIG. 4, and the effect of suppressing supercooling can be stably obtained as described above.

C as nucleating agent next _{K 2 HPO 4 · 6H 2 O} ( active ingredient)
at least one selected from the group consisting of aCl ₂ , CaS, and CaSiO ₃ , and Ca ₂ P ₂ O ₇ , Ca ₂ P ₂ O ₇ , and Ca
₃ (PO ₄ ) · 2H ₂ O, CaHPO ₄ · 2H ₂ O, Z
n 3 _(PO 4) shows a supercooling suppression effect of one or more selected from the group consisting of ₂ · _4H 2 _O are contained in combination as shown in Table 5 in Figure 5.

As shown in FIG. 5, even when the nucleating agents were combined as described above, the same effect of suppressing supercooling as described above could be obtained.

It is possible to prevent the occurrence of supercooling phenomenon was a disadvantage of K ₂ HPO 4 · _{6H 2 O,} which is a main component by adding an appropriate amount of nucleating agent as shown in the above embodiment, the latent heat per unit weight amount has become possible to effectively utilize the advantages of large _{K 2 HPO 4 · 6H 2 O} . That is, it has become possible to provide a heat storage material composition which has a large amount of heat generated (or an amount of heat absorbed) at a use temperature and has little change in performance even after repeated melting and solidification.

Although the heat storage material composition according to the present invention is as described above, it is customary to use an appropriate amount of a thickener and a freezing point adjusting agent in combination in practical use as a heat storage material. Of course, it is permissible to appropriately add subcomponents. Even when these subcomponents are added, the heat storage material composition of the present invention does not cause a decrease in the amount of latent heat or a significant supercooling phenomenon.

The composition and freezing point of a typical heat storage material composition of the present invention containing these subcomponents and the degree of supercooling (average value when repeated 10 times) are also shown below.

(A) a main component _{(K 2 HPO 4 · 6H 2} O): the balance freezing point modifiers _{(K 2 HPO 4): 10} % nucleating agent _{(CaCl 2, Ca 2 P 2} O 7): 1% thickener (Ultra Fine powder silica): 2% Freezing point: 5 ° C., degree of supercooling: 0.7 ° C. [Effect of the invention] The present invention is configured as described above, and K ₂ which is the main component.
By adding the nucleating agent HPO ₄ · 6H ₂ O,
K 2 _HPO 4 · _6H 2 succeeded by eliminating _O supercooling phenomenon was a drawback, it is possible to make use of the feature that the latent heat per unit weight is large. Thus, K ₂ HP was initially thought to be difficult to put into practical use as a heat storage material.
The _O 4 _· 6H 2 O-containing composition could be a composition excellent heat storage properties.

[Brief description of drawings]

FIG. 1 is a graph showing basic experimental data,
The figure is a graph showing the degree of supercooling of the heat storage material composition according to the present invention.

Claims (2)

[Claims] 1. A _{K 2 HPO} 4 · 6H 2 O was used as a main component, CaCl _2, CaS as a nucleating agent for preventing supercooling, CaSi
A heat storage material composition comprising one or more kinds selected from the group consisting of O ₃ . Wherein _{K 2 HPO} 4 · 6H 2 O was used as a main component, CaCl _2, CaS as a nucleating agent for preventing supercooling, CaSi
One or more selected from the group consisting of O ₃ and Ca ₂ P ₂ O
_{7, Ca 3 (PO 4)} 2 · 2H 2 O, CaHPO 4 · 2
_{H 2 O, Zn 3 (PO} 4) heat storage material composition characterized by formed by incorporating a combination of one or more selected from the group consisting of ₂ · 4H 2 O.