JPS5850277B2 - chikunetzai - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition that has practical value as a heat storage material for air conditioning.

Various heat storage materials for cooling have been known and used in the past, but for example, tetradecane (C14H301 melting point 5
Since paraffins such as (℃) have low thermal conductivity, the coefficient of performance when storing heat using a heat pump does not improve as much as expected, and it is difficult to use a heat storage material that is a mixture of inorganic compounds with water of crystallization. Certain calcium chloride hexahydrate (CaCl
2.6H20) 50 mol% and calcium bromide hexahydrate (C
A substance containing 50 mol% of aBr2.6H20) has a relatively high melting point of around 15°C, so its use is limited to a certain extent.

In addition, sodium sulfate 1 whose melting point is 12.8°C
0 hydrate salt (Na S Qll 0 H20) 50 mol%,
A ternary system consisting of 25 mol% ammonium chloride (NH4Ct) and 25 mol% sodium chloride (NaCt) has a heat of fusion of 43 catAf, but its melting point is the peritectic reaction point, and upon melting, it produces insoluble sodium sulfate and solidifies. Sometimes, when the peritectic reaction is not completed and the heat cycle is repeated, insoluble matter settles to the bottom of the vessel, and its ability as a heat storage material is inevitably reduced significantly, so only a thin heat storage tank of a few millimeters is used at most. The reality was that none of them could be said to be sufficient.

The present invention was achieved as a result of research in order to overcome the drawbacks of conventional products. A binary system or lithium nitrate trihydrate and magnesium bromide hexahydrate (MyBr2.
It was discovered that a binary system consisting of 6H20) has a harmonic melting point around 10° C. and has a large heat of fusion, producing an optimal mixture as a heat storage material for air conditioning.

Of course, magnesium chloride hexahydrate and magnesium bromide hexahydrate are similar substances, and the mixing molar ratio of the two can be arbitrarily changed to create a mixture of lithium nitrate trihydrate - magnesium chloride hexahydrate and magnesium bromide hexahydrate. It can also be used as an original mixed system.

* The table below shows the main physical properties of the lithium nitrate trihydrate-magnesium chloride hexahydrate mixture.

In addition, compositions with sample numbers in the above table are indicated using the same numbers in the pseudo-ternary system phase diagram shown in the attached drawings, and the same applies to the following tables.

In the attached drawings, the horizontal axis I is the mol% number of lithium nitrate trihydrate, and the horizontal axis ■ is the mol% number of magnesium chloride hexahydrate.
The mol% number of magnesium bromide hexahydrate is taken on the number and horizontal axis ■, and the circles with Arabic numerals indicate the composition points of the corresponding sample numbers in Table 1 above and Tables 2 and 3 below. shall be.

In addition, the two solid lines marked (1:1) and (1:3) in the attached drawings represent the compositional molar ratio of magnesium chloride hexahydrate and magnesium bromide hexahydrate, and any line on the line segment This shows that the same molar ratio is maintained even at the location.

The diagonally shaded area surrounded by dotted lines indicates the composition ratio of the present invention.

As shown in Table 1 above, magnesium chloride hexahydrate was added to
A composition containing 1.1 mol% of magnesium chloride hexahydrate is unsuitable for cooling because the high-temperature phase has a melting point of 20°C or higher and the high-temperature phase is predominant.
Although the material containing 7 mol % produced a high temperature phase, its melting point was 13 to 16°C and the low temperature phase was predominant, making it suitable for a heat storage material for air conditioning.

Further, in the case containing 33.3 mol%, another high-temperature phase rich in magnesium chloride hexahydrate predominates and the heat of fusion is very small, which is also not suitable for practical use.

Therefore, the magnesium chloride hexahydrate content is 14 mol%.
It can be said that a mixture having a content of 27 mol % or less is suitable for practical use.

The specific gravity of a liquid mixture containing 16.7 mol% of magnesium chloride hexahydrate is 1.41? /cc, so the heat of fusion is 59.1 cal/cc or more per unit volume, and 2
The liquid specific gravity of something containing 2.2 mol% is 1.41? /cc
Therefore, the heat of fusion per unit volume is 48.9 cat/
cc or more.

The following table shows the main physical properties of the lithium nitrate trihydrate-magnesium bromide hexahydrate mixture.

If the concentration of magnesium bromide hexahydrate is less than 10 mol%, the melting point of the high temperature phase will exceed 20°C, making it unsuitable for cooling, but if the concentration is 11.1 mol%, the melting point of the high temperature phase will be 20°C or less. The material was large and had a predominant low-temperature phase, so it could be used as a heat storage material for air conditioning.

Also, if it contains 27 mol% or more, another high-temperature phase rich in magnesium bromide hexahydrate is formed, and the heat of fusion is 20 cat.
/f or less, which is also not practical.

Therefore, it has become clear that mixtures having a concentration of magnesium bromide hexahydrate between 10 mol% and 27 mol% are practical.

The densities of the liquid mixtures are 1.46, 1.51 and 1.53☆☆P/cc for magnesium bromide hexahydrate concentrations of 11.1, 16.7 and 22.2 mol%, respectively. Therefore, the heat of fusion per unit volume is 60.9, 57.4, and 43.0 ca, respectively.
l/cc or higher, which was found to be almost the same as the aforementioned lithium nitrate trihydrate-magnesium chloride hexahydrate mixture.

Next, Table 3 shows an example in which lithium nitrate trihydrate was mixed with magnesium chloride hexahydrate and magnesium bromide hexahydrate at the same time.

That is, from the table above, by simultaneously mixing magnesium chloride hexahydrate and magnesium bromide hexahydrate with lithium nitrate trihydrate, the melting point of the low temperature phase decreases to around 6°C, but the heat of fusion hardly decreases. Lithium nitrate trihydrate mentioned above -
Compared to magnesium chloride hexahydrate-based or lithium nitrate trihydrate-magnesium bromide hexahydrate-based materials, it has improved properties suitable for use as a heat storage material for air conditioners, and also has many problems such as being less susceptible to supercooling and breaking. It is shown that it has excellent characteristics.

However, sample number 10 in Table 3 above is 15.3-20℃
Although a high-temperature phase with a melting point of It is unsuitable for practical use.

Examples will be described below.

Example 1 Magnesium chloride hexahydrate was mixed with 430.5A-9 of lithium nitrate trihydrate to 203.3%, that is, 22.2 mol% in terms of magnesium chloride hexahydrate content, to form a supercooling prevention material. as 0.1% by weight of cryolite (Na5AI F6
) and melt it, then put it in a heat storage tank.

Example 2 Magnesium bromide 6 in lithium nitrate trihydrate 615A-9
A mixture of 292.2 kq of aqueous salt, that is, 16.7 mol % in terms of magnesium bromide hexahydrate content, is used as a heat storage material.

Example 3 The ratio of 203.3 kf of magnesium chloride hexahydrate and 292.2 Ay of magnesium bromide hexahydrate to 1045.5 Ay of lithium nitrate trihydrate, that is, 81.0 mol% of lithium nitrate trihydrate and 6 mol% of magnesium chloride Water salt and magnesium bromide hexahydrate were mixed together at a ratio of 9.5 mol %, melted, and then placed in a heat storage tank.

Example 4 Ratio of lithium nitrate trihydrate 172.2A-9, magnesium chloride hexahydrate 20.3 to 9 and magnesium bromide hexahydrate 87.7 kg, that is, lithium nitrate trihydrate:
Magnesium chloride hexahydrate: Magnesium bromide hexahydrate
After mixing and melting at a ratio of 7.7: 5.6: 16.7 mol%, the mixture is placed in a heat storage tank.

[Brief explanation of drawings]

The drawing shows lithium nitrate trihydrate - magnesium chloride hexahydrate -
1 shows a plan view of a pseudo-ternary system phase diagram made of magnesium bromide hexahydrate. I is L 1NO3・3H20−M3H2O−・6H20
The axis represents the composition ratio of L i NOa・
The number of mole % of 3H20 is shown. ■ is MgCl2・6H2o-Mgct2~MgBr2・
The axis represents the composition ratio of 6H20, and the numbers on the axis are MgCl
Shows the number of moles of 2.6H2o. ■ is the axis representing the composition ratio of MgBr2'6H20-LtNO3''3H20, and the numbers on the axis are MgBr2'6H20-LtNO3''3H20.
6H2o) Shows the L/% number. A...LiNO3.3H2086 mol%teMf
Regarding the composition ratio of Ct2.6H2014 mol%. B・・・・・・L 1NOs・3H2073 mol% M
, the point of the composition ratio of C4.6H2027 mol□. C...L I NOs.3H2073 mol% and MyBr2j 6H2027 mo7L/% composition ratio point. D""...MyB at LiNO3'3H2090moiv%
Regarding the composition ratio of r2.6H2010 mol%. Note that in the drawings, the circles with numbers 1 to 16 indicate the compositions of the respective sample numbers.

Claims (1)

[Claims] 1 Lithium nitrate trihydrate (LiNO2.3H20) is the main component, and magnesium chloride hexahydrate (M, C12
・6H20) and/or magnesium bromide hexahydrate (
In a composition formed by mixing MyBr2.6H20), in the case of a two-dimensional phase, the content of MfC12.6H20 is 1.
4 to 27 mol% or the content of M1Br2.6H20 is 1
The composition ratio is 0 to 27 mol%, and in the case of a ternary phase, with reference to the pseudo-ternary phase diagram in the attached drawing,
iNO2・3H2086 mol% M, Ct2・6H20
Point A and LiNO2.3H20 showing a composition ratio of 14 mol%
LiNO2.3H2073 on the B point and ■ axis showing a composition ratio of 73 mol% and MfIC12.6H2027 mol%
M in mole □? Point C showing the composition ratio of B r 2.6H2027 mol% and Mf at 90 mol% of LiNO2.3H2
A heat storage material characterized by having a composition ratio within a region represented by a trapezoid formed by sequentially connecting four points D indicating a composition ratio of IB r2 a6H2010 mol%.