JPS59187076A - Heat accumulative material - Google Patents

Abstract

PURPOSE:A heat accumulative material for heating of passive solar house, hothouse, etc., obtained by adding sodium sulfite.7 hydrate or anhydride to a system containing sodium sulfate.10 hydrate and sodium carbonate.10 hydrate. CONSTITUTION:A system containing sodium sulfate.10 hydrate and sodium carbonate.10 hydrate in a molar ratio of preferably (5:4)-(1:2) is blended with at least one of sodium sulfite.7 hydrate or sodium sulfite anhydride in a molar ratio of preferably (0.95:0.05)-(0.85:0.15), to give the desired heat accumulative material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates primarily to a heat storage material used for passive solar heating, greenhouse heating, and the like.

Conventional configuration and its problems During the winter, sodium sulfate decahydrate (Na2
SO4・10H20) and carunium chloride hexahydrate (CaC
12.6H20) is well known. The former is about 32℃
Although the latter has a melting point of about 29°C and can be used in the Pansibunula heating system, it has been desired to lower the melting point to 20 to 26°C in order to make it more versatile. In a previous application, the present inventors have proposed a novel heat storage material with a melting point of about 24°C, namely Na2S.
Although a eutectic mixture of O4.1oH2o and Na2CO3.1oH20 was disclosed, as a result of considering the application of the heat storage material to greenhouse horticulture (vinyl gardening) in this earlier application, it was found that the melting point could be further lowered to approach 20'C. The conclusion was that it is desirable.

Purpose of the Invention In view of the above circumstances, the present invention provides the above-mentioned Na2SO4.1QH20 and Na2CO3@10H20.
This was done in order to further lower the melting point of a heat storage material made of a eutectic mixture of

Structure of the Invention The heat storage material of the present invention includes Na2SO4・10H20 and Na
Contains at least 2CO3・1oH20, and further contains sodium sulfite heptahydrate (Na2S○3・”'rH20)-4
Obtained by adding bamboo shoot sodium sulfite anhydride (Na2sO3). The characteristics of the present invention are 1 (a2 SO4・10H
The melting point of the heat storage material whose main components are 20 and Na2CO3・1QH20 is Ma2SO3・7H20 or Na2SO3
This was further reduced by adding .

It is sufficient that the Na 2 SOs 7H20 is substantially contained, and in addition to using Na2SO3 7H2Q alone as it is, a stoichiometric amount of water necessary to generate Na 2 SOs and its heptahydrate is used. It is also possible to use both.

In addition, the presence or absence of a nucleating agent to suppress supercooling, a gelling agent, a surfactant, etc. to improve properties does not change the basic structure of the present invention, and does not affect the gist of the present invention. It's not something to deviate from.

Description of Examples <Example 1> Na25o4.1QH20, Na2CO3.10H20 and Na2SO3.7H20 in molar ratio (1-x)/
2: (1-x)/2: Mix at a ratio of x, x
-0,05.

Four types of samples of 0.10, 0.15, and 0.20 were prepared.

The sample contained 3% H borax (Na2B) as an anti-supercooling agent.
407・1oH2Q), which contains 2% by weight of crosslinked acrylic acid polymer as a phase separation inhibitor, but these
It was confirmed that it had almost no effect on the melting point of These samples were placed in an approximately 3 oi sealed polyethylene container, a thermocouple for temperature measurement was inserted into the center of the sample, and the temperature profile of melting and solidification was measured.
7 Compared with that of X=O which does not contain H2O. As shown in the figure, when the x-o sample was completely solidified in a water bath at 10°C and then melted in a water bath at 30°C, melting started at a sample temperature of about 23°C, and melting started at about 24°C. Thawing was complete at 6°C.

The melting start temperature for the sample with X=0.05 is approximately 22°C.

The melting completion temperature is about 23.5'C, for the sample yc-0,1 the former is about 21-5'C; + the latter is about 23"0., x-0
, 16 samples, the former is about 21.5'C and the latter is about 23.5'C.
℃, and for the sample with X=0.2, the former was approximately 20'C and the latter was approximately 24°C, both of which were observed to be under the same image. However, as X increases, the difference between melting start temperature and melting completion temperature tends to increase, and the time required from melting start to completion tends to decrease. It is noticeable in The latter trend indicates a decrease in heat storage,
Therefore, the range of X is preferably 0.06 to 0.16, and a particularly desirable range is 0.05 to 0.1.

<Example 2> Molar ratio of Na25O4e10H20, Na2CO3 0H2o and Na2SO3・7H2o: (0-9-
y): mixed at a ratio of 0.1, y=0.55, 0.
50, 0.45° 0.40, 0.35, 0.30, 0.
25 seven types of samples were prepared. The supercooling inhibitor and phase separation inhibitor were added in the same manner as in Example 1. 7=0.
Sample No. 45 is the same as sample X-○ and No. 10 in Example 1, and the melting curves of the samples with y in the range of 0.60 to 0.30 are significantly different from those with y = 0.45. However, considerable changes were observed in the melting curves of samples with y of 0.55 and 0.25, and in addition to the similar phase with a melting point between 22 and 23 degrees Celsius, a phase with a melting point between 27 and 28 degrees Celsius appeared. It was found to be unsuitable for the purposes of the present invention. Therefore,
Na2SO4・io H2O and Na2CO3-1
For the sum of moles of 0H20, Na2SO3・7H2
When the molar ratio of 0 is o, i, the range of y is 0.50 to 0.
30. That is, Na2SO4・10H2°tNa2C
It is desirable that O3-1QH20 be contained in a mo/lz ratio of 0.50:0.40 to 0.30:o, eo.

Also, Na2SO4・1oH20 and Na2cO3・1oH
For the sum of moles of 2Q, Na2SO3・7)(20
Mo/l/number is o, 95:0.05 to o, aes:o
, 16, even if Na2SO3.7H20 is added to the range of 16, the above range, that is, Na2SO4.10
H20 and Na2CO3・10H20 0.33) Knee (
= 0.67), no phase with a melting point between 273°C and 28°C was observed, indicating desirable properties.

<Example 3> A sample was prepared in the same manner as in Example 1 except that Na2SO3 was used instead of N2SO3.7H2o7), and measurements were performed, and almost the same results as in Example 1 were obtained.

In addition, the present inventors have reported in the earlier application that sodium sulfate 1
Although a heat storage material which is mainly composed of o hydrate and sodium carbonate hydrate and further contains at least one of sodium chloride, potassium chloride, or urea in order to lower the melting point, the invention based on these earlier applications and the present invention It goes without saying that the same effect of lowering the melting point can be obtained even when these are combined.

Effects of the Invention As described above, the present invention provides a heat storage material containing at least sodium sulfate decahydrate and sodium carbonate decahydrate, and at least one of sodium sulfite decahydrate and sodium sulfite anhydrous. Added to lower the melting point, 20″
The heat storage material according to the present invention is particularly useful for heating systems for pasocipunlar heating systems and greenhouse horticulture.

[Brief explanation of the drawing]

The figure is a diagram showing an example of a melting curve of a heat storage material according to the present invention.

Claims (1)

[Scope of Claims] (A heat storage material characterized by containing at least sodium sulfate monohydrate and sodium carbonate monohydrate, and further adding at least one of sodium sulfite heptahydrate or sodium sulfite anhydride. (2) The ratio of the number of moles or the sum of the number of moles of either sodium sulfite heptahydrate or sodium sulfite anhydride to the sum of the number of moles of sodium sulfate decahydrate and sodium carbonate monohydrate is 0.96 = 0.05 to 0.85
:0.15. (3) The heat storage material according to claim 1, wherein the molar ratio of sodium sulfate 1O hydrate to sodium carbonate 1O hydrate is in the range of 6=4 to 1:2.