KR970006716B1 - Heat sink material using latent heat of coal - Google Patents

Abstract

The heat accumulated material of latent heat is produced by mixing 85-94.1 wt.% a sulfate of soda for industry as a main latent heat materials, 3.4-10 wt.% a coal as a nucleating agent and 2.5-5 wt.% a high absorbing polymer as a thickener. The heat accumulated material of latent heat is economical by producing without melting the constituent components and is contributed to energy recycling by using the coal.

Description

Latent Heat Storage Material and Production Method Using Briquette Material

1 is a repeating melting and solidification experiment apparatus of the heat storage material of the present invention.

2 is a temperature change curve of the heat storage material according to the time of solidification after the melting and solidification repeated experiment of the heat storage material of Example 1 of the present invention.

* Explanation of symbols for main parts of the drawings

1: Temperature recorder 2: Phase change material tank

3: thermostat 4: hot water bath

5: cold water tank 6: temperature controller

7: pump 11: thermostat temperature

12: heat storage material temperature 13: cooling start

14 latent heat release

The present invention relates to a latent heat storage material and a method for manufacturing the same, and more particularly, to a latent heat storage material obtained by simply mixing a superabsorbent polymer, briquette or borax in an industrial forget-me-not, which is a main latent heat material. .

With the development of the industry, the demand for energy is exploding, and in countries such as Korea, where there is absolutely no energy resources, the development of alternative energy utilization technology by solar, geothermal, wind, tidal, etc. Effective utilization measures are urgently needed.

During the development of technology related to the use of energy, in the field of using alternative energy, energy storage technology for converting energy sources into regular and continuous energy sources has emerged as an urgent and urgent task. have.

There are four main types of energy storage: thermal energy in latent and sensible states, electromagnetic energy induction field or electrical energy, mechanical energy in kinetic or potential energy, and chemical or nuclear energy in its own right. Is stored in the form.

Among the thermal energy storage systems, the first problem to be solved is the development of a heat storage device having high efficiency and a high energy storage density. A representative method known so far among the storage methods of heat energy used in the heat storage device is described above. As described above, there is a sensible heat storage method and a latent heat storage heat storage method using a single phase material as a heat storage medium, but a latent heat storage thermal energy storage method using a heat storage medium has a high heat storage density per unit volume and can store heat within a small temperature difference range. Therefore, it is attracting attention as an efficient heat storage method.

The heat storage system using latent heat has a larger heat storage capacity than the heat storage system using sensible heat, which greatly reduces the size and installation cost of the device, and has the advantage of allowing heat storage and heat radiation at a substantially constant temperature.

This latent heat storage system has been actively researched since the 1940s and has undergone two energy crises in the 1970s.

To be an effective latent heat storage material, it is necessary to satisfy the following conditions.

(1) The phase change should occur at a constant temperature and the phase change temperature should be consistent with the operating temperature range.

(2) The heat storage capacity per unit volume and unit weight should be large.

(3) There should be no phase separation phenomenon.

(4) There should be no supercooling phenomenon.

(5) The crystal growth rate should be large.

(6) The thermal conductivity is to be large.

(7) The volume change due to the phase change should be small.

(8) The vapor pressure is to be small.

(9) It should be chemically stable and not corrosive.

(10) The material must be inexpensive and readily available.

However, in reality, there is no heat storage material that satisfies all of the above conditions, and each has its advantages and disadvantages, so it is necessary to select a material that satisfies each condition as the latent heat storage material.

For example, paraffin or higher fatty acids have no advantages in phase separation or supercooling and are not corrosive, but they are difficult to use as latent heat storage materials due to their low heat storage capacity per unit volume.

Inorganic hydrates such as sodium sulfate (sodium sulphate) and sodium phosphate are currently being studied the most, and they are difficult to be used directly as a latent heat storage material due to the severe phase separation phenomenon and the high degree of supercooling when the heat storage and heat dissipation process is repeated.

Therefore, an appropriate nucleating agent is used to prevent supercooling, and the nucleating agent is a growth substrate of immature nucleus, which is the foremost step of nucleation, and increases the safety of immature nuclei, thereby reducing the activation energy required for nucleation. In addition, in order to prevent phase separation, rotating or physically stirring a container containing a latent heat storage material, adding a thickening agent to increase the viscosity of the melt to prevent sedimentation of anhydrous salt, and polymer matrix absorbing crystal water Is applied, but research on the method using the polymer matrix is the most active.

On the other hand, various changes have been sought in the form of the latent heat storage material, but most of them are melt-mixed forms of the composition, which requires considerable heating in the production of the latent heat storage material. The process of maintaining is inevitable.

The present invention solves these shortcomings, and an object of the present invention is to simply add super absorbent polymers, briquettes or boraxes to industrial forages, not for reagents, so that they do not melt the components and contribute to energy recycling using coal briquettes. To provide a latent heat storage material.

In the method of preparing the latent heat storage material according to the present invention, crosslinking reaction is performed by directly adding and mixing the superabsorbent and high swellable polymers which have already been crosslinked to form a three-dimensional matrix by adding crystal water or a crosslinking accelerator. It completely eliminates the inconvenience of having to make it along the way.

In other words, when industrial temperature is blended with a primary mixture of briquettes as nucleating agents and high swellable and superabsorbent polymers as phase separation agents, and the temperature is raised above the melting point, the crystal water of the hydrate penetrates into the polymer to form a hydrogel. No matter how repeated melting and solidification of branched hydrates, the undissolved anhydrous salts do not penetrate, thereby preventing phase separation and supercooling.

In addition, in the present invention, the briquettes are added, and the briquettes are mixed to have a synergistic effect of preventing phase separation of the hydrate, an effect of increasing the role as a nucleating agent, a volume maintenance and an airtight reinforcement role that do not break the state of the forget-me-not. .

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

After changing and combining the content weight ratio (Wt%) of latent heat storage material, the experimental apparatus of FIG. 1 which consists of a heating part and a cooling part was comprised in order to measure latent heat temperature and subcooling degree in heating and cooling process.

The operation of the pump (7) during the heating and cooling process was automatically enabled by the control box when the phase change from the latent heat material to the solid and liquid phase was completed.

The temperature sensor in the thermostat (3) is inputted into the control box so as to be kept constant at 10 ° C in the cooling process and 48 ° C in the heating process, and the temperature change of the latent heat storage material contained in the acrylic tube is connected to the temperature recorder (1). Can be.

Water swellable polymer using the apparatus of FIG. 1 equipped with a temperature recorder (1), a phase change material tank (2) immersed in a thermostat tank (3), a hot water tank (4), a cold water tank (5), and a thermostat (6) The optimum mixing composition was obtained by varying the amount of briquette or nucleating agent added. The latent heat storage material of the present invention was obtained by the following process by the optimum mixing composition.

10 g of briquettes and 5 g of superabsorbent polymer (polyacrylate-based crosslinked product, GS-2000) were added to 85 g of industrial manganese (Na ₂ SO ₄ , 10H ₂ O), followed by simple stirring to obtain a desired latent heat storage material.

The latent heat storage material obtained above is placed in the melting and solidification repeating apparatus of FIG. 1, and the result of temperature change of the latent heat storage material with time upon solidification after 600 or more melting and solidification repeating experiments is shown in FIG.

As can be seen in Figure 2, the latent heat storage material of the present invention does not appear in the phase separation phenomenon and supercooling phenomenon even in more than 600 melting and solidification repeated experiments, the temperature of the latent heat material at the melting point where the latent heat occurs after the temperature starts to drop It was confirmed that it remained almost constant for a long time without the supercooling phenomenon.

Example 2

It carried out similarly to Example 1 except having performed the latent heat storage material manufacturing process of Example 1 as follows.

To 85 g of industrial forget-me-not, 6 g of briquettes, 5 g of superabsorbent polymers, and 4 g of borax were added and stirred and mixed to prepare a latent heat storage material.

The latent heat storage material of the present invention obtained as described above is obtained by adding a briquette material as a nucleating agent, unlike the usual latent heat storage material, and by stirring and mixing the constituents in the usual mixing form without melting the main latent heat storage material, This eliminates the need for heating or the need for a heat retention system to maintain the liquid until filling is complete. It is extremely practical because there is no problem caused by the volume change between and latent heat substance.

Claims (4)

85 to 94.1 weight% of industrial manganese (Na ₂ SO ₄ , 10H ₂ O) as the main latent material, 3.4 to 10 weight% of the briquette material as the nucleating agent and 2.5 to 5 weight% of the super absorbent polymer as the middle agent Method for producing a latent heat storage material using a briquette. The latent heat storage material obtained by the manufacturing method of Claim 1. The method for producing a latent heat storage material using briquettes according to claim 1, wherein briquettes are used in an amount of 2.4 to 6% by weight and borax 1.0 to 4% by weight. The latent heat storage material obtained by the manufacturing method of Claim 3.