JPS61155487A - Preparting heat-storing material - Google Patents

Abstract

PURPOSE:To produce a heat-storing material at low cost and with high productivity, by adding water to a system containing sodium acetate trihydrate, anhydrous sodium acetate and the base of a supercooling-preventing agent to adhere the crystals of sodium acetate trihydrate on the surface of the base of the supercooling-preventing agent. CONSTITUTION:A vessel is charged with sodium acetate trihydrate, anhydrous sodium acetate and the base of a supercooling-preventing agent (for example, Na4P2O7). Then, a small amount of water in the form of a liquid or gas is added to the vessel to adhere the crystals of sodium acetate trihydrate on the surface of the base of the supercooling-preventing agent, to thereby obtain an intended heat-storing material. By the process of the present invention the adherence of the crystals of sodium acetate trihydrate on the surface of the base of a supercooling-preventing agent can be effected simultaneously with the enclosing of a heat-storing material Therefore, the process of the present invention can be advantageously employed to prepare a heat-storing pack by enclosing a heat-storing material in a small vessel.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing a latent heat storage material mainly composed of sodium acetate trihydrate.

BACKGROUND ART In general, heat storage materials that utilize the sensible heat of substances and those that utilize latent heat are known. Heat storage materials that use latent heat have a larger amount of heat storage per unit weight or unit volume than heat storage materials that use sensible heat, and only a small amount is required to store the required amount of heat. It becomes possible to downsize the heat storage device. In addition, heat storage materials that utilize latent heat have the characteristic that, unlike heat storage materials that utilize sensible heat, the temperature does not decrease as heat is radiated, and the heat is radiated at a constant temperature at the 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.

By the way, conventionally sodium acetate trihydrate (cH3■)
h.aH2O (melting point: 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, once CH3CO2Na.3H2O is melted, it is very easy to become supercooled, so the supercooling cannot be broken unless the melt is cooled to about -20°C. The supercooled state is a phenomenon in which even if the material is cooled to the freezing point, the latent heat of fusion is not released and the material is cooled below that temperature, which is fatal to heat storage materials that utilize the latent heat of fusion.

In order to prevent this CH3CO3Na.3H2O from being supercooled, it has been proposed to mix various additives. For all of these additives, it is necessary to attach CH3GO2Na.3H2O crystals to the particle surfaces in advance (Japanese Patent Publication No. 8-027301:).

Therefore, a (a mixture of 3CO2Na and 3H2O and the base material of the supercooling prevention material is heated in advance and CH3CO3N
After melting a.3H2O, cool it (if necessary, add C
H3C2Na, with the addition of 3H2O crystals), CH3
It was necessary to crystallize CO2Na.3H2O and deposit cH3a)2Na.3H2O crystals on the surface of the base material of the supercooling prevention material.

Problems to be Solved by the Invention Incidentally, this method of manufacturing a heat storage material has a problem in that it is troublesome to operate and is not suitable for mass production.

When sealing the encased heat storage material in a container, after sealing,
Since it is difficult to add seed crystals of CH3CO2Na.3H2O, it was necessary to produce a large amount of heat storage material in advance and separately seal it in each container. By the way, once CH3CO2Na.3H2° is melted, it becomes a solid case like ice,
It is necessary to thoroughly crush it before dividing it into containers. Therefore, such a manufacturing method has a problem in that the manufacturing cost of the heat storage material becomes extremely high.

The present invention solves these conventional problems, and allows crystals of 0 (2co2Na and 3H2O) to be attached to the surface of the base material of the supercooling prevention material almost simultaneously with the encapsulation of the heat storage material. The present invention provides a method for producing a heat storage material that is particularly advantageous when sealing the heat storage material in a container.

Means for Solving the Problems In the method for producing a heat storage material of the present invention, at least CH
3CO2Na, 3H2O, and CH, Co2Na and C
Water is mixed into a system containing a base material of H3CO2Na/3H2Q supercooling preventive material, and 0(
3CO2Na.3H2O crystals are deposited. The state of water may be either liquid or gaseous water vapor.

Function: In the method for producing a heat storage material of the present invention, a(3CO2Na・3
In the presence of H2O, water is added to the a(3CO2Na particles, so the surface of the CH3CO2Na particles becomes CH3α 逼Na・3H2o. By the way, since the base material of the supercooling prevention material is also mixed in, Similarly, at the point of contact between the base material particles of the anti-cooling material and the CH3CC)2Na particles, C)L
3CO2Na3co2Naa becomes ω-a・3chi0.

As a result, CH3CO2 appears on the surface of the base material particles of the supercooling prevention material.
It becomes a state where Na.3 town ρ is attached.

Examples Example 1 CH3CO3Na・3H2O10t and CH3CO
2Na 1.2y, and Na4P2O7o, 5? as a base material for supercooling prevention material. The mixture was filled into a container made of laminated film, and 0.8 f of water was added thereto by misting.

Thereafter, the container was sealed and left at room temperature for a while, and then the container containing the heat storage material was sufficiently stored in a water path at 70°C. Thereafter, when the container was taken out and cooled to room temperature, CH3CO2Na.3H2o crystallized with almost no supercooling, confirming that the heat storage material produced by the manufacturing method of the present invention had sufficient functionality.

Example 2 CH3CO2Na・3H2O10 and CH3CO2N
a 1.2 f and L as a base material for supercooling prevention material.
iF 0.6f into a container made of laminated film, and the container was kept at room temperature and relative humidity of about 9o.
% in a constant humidity chamber for about 2 hours, and the container contains 0.22
of water was absorbed. After that, the container was sealed and the reversibility of heat storage and heat radiation was confirmed in the same manner as in Example 1.
There were no problems, and it was found that the heat storage material produced by the manufacturing method of the present invention had sufficient functionality.

Effects of the Invention As described above, the method for producing a heat storage material of the present invention is characterized in that at least C) I3CO2Na -5H2O and CH3CO2Na
In addition, water is mixed into the system containing the base material of the supercooling prevention material of 0(3CO2Na/3H2O), and the crystals of CH3CO2Na/3H2O are attached to the surface of the base material of the supercooling prevention material, so the manufacturing process is It is simple and advantageous for Tendo production,
Therefore, manufacturing costs can be significantly reduced compared to conventional methods. In particular, in the manufacturing method of the present invention, 0L3CO is added to the surface of the base material of the supercooling prevention material at the same time as the heat storage material is enclosed.
Since crystals of 2Na and 3H2O can be attached, it is extremely advantageous when sealing a heat storage material in a small container to produce a heat storage puncture.

Claims (2)

[Claims] (1) At least sodium acetate trihydrate (CH_3CO
_2Na・3H_2O) and sodium acetate anhydrous (CH
_3CO_2Na), and sodium acetate trihydrate (C
A method for producing a heat storage material, in which water is mixed into a system containing a base material of a supercooling preventive material (H_3CO_2Na・3H_2O), and crystals of sodium acetate trihydrate are attached to the surface of the base material of a supercooling preventive material. (2) The method for producing a heat storage material according to claim 1, wherein the water is steam.