CN114806509A - Cold storage phase change cold storage material and preparation method thereof - Google Patents

Abstract

The invention discloses a refrigerated phase change cold storage material and a preparation method thereof, belonging to the technical field of phase change energy storage. It includes a phase change component and an additive, the phase change component is composed of 66.15-76.55 parts by mass of energy storage agent, 13.4-17.2 parts by mass of organic temperature regulator and 8.85-13.05 parts by mass of inorganic temperature regulator, and the additive is composed of 0.5-2.0 parts by mass parts of nucleating agent, 0.5-1 parts by mass of thermal conductivity enhancer, 0.1-0.3 parts by mass of thickener, and 0.1-0.3 parts by mass of distilled water; the phase transition temperature of sodium sulfate decahydrate is adjusted after compounding with various temperature regulators, The phase transition temperature of the obtained material is 1.2-3.0° C., the latent heat of phase transition is 124-158kJ/kg, and the thermal conductivity is greater than 0.7W/m·k. It is pollution-free and has wide application prospects.

Description

A kind of refrigeration phase change cold storage material and preparation method thereof

technical field

The invention belongs to the technical field of phase change energy storage, and particularly relates to a refrigerated phase change cold storage material and a preparation method thereof.

Background technique

In recent years, with the continuous development of my country's economy, cold chain, as an emerging industry, is booming. With the development of cold chain logistics, phase change materials have been widely used in food cold chain transportation and pharmaceutical cold chain logistics. Using the principle of phase change cold storage, according to the different temperature requirements of cold chain transportation, the reasonable configuration of cold storage materials with different phase change temperatures can meet the specific requirements of cold chain logistics, and phase change materials can avoid the traditional mechanical refrigeration. Problems such as difficulty in monitoring and vulnerability to force majeure factors.

At present, the phase change materials of non-aqueous system are mainly used in the refrigeration of food and medicine, which are mainly partial alkanes, non-alkanes and mixtures of the two. Problems such as pollution to the environment, water body, and easy leakage from the surface of the packaging material limit its practical application effect.

SUMMARY OF THE INVENTION

The invention provides a refrigerated phase-change cold storage material and a preparation method thereof, and a composite phase-change material for refrigeration at 1.2-3.0° C. is prepared. The phase-change material has a large thermal conductivity, low price, green environmental protection and easy packaging.

In order to achieve the above purpose, the present invention adopts the following technical scheme: a refrigerated phase change cold storage material, the phase change material includes a phase change component and an additive, and the phase change component is composed of 66.15-76.55 parts by mass of energy storage agent, 13.4-17.2 parts of organic temperature regulators and 8.85-13.05 parts by mass of inorganic temperature regulators, the additives are composed of 0.5-2.0 parts by mass of nucleating agents, 0.5-1 parts by mass of thermal conductivity enhancers, 0.1-0.3 parts by mass of thickeners, 0.1-2. 0.3 parts by mass of distilled water.

Among the above components, the energy storage agent is sodium sulfate decahydrate, the organic temperature regulator is sodium formate, and the inorganic temperature regulator is composed of 2.85-5.55 parts by mass of sodium chloride, 6-7.5 parts by mass of bromide Sodium composition; the nucleating agent is sodium tetraborate, the thermal conductivity enhancer is graphite, and the thickening agent is sodium polyacrylate.

A preparation method of a refrigerated phase change cold storage material, comprising the following steps:

(1) Melt the energy storage agent at a constant temperature of 40-45°C; add an organic temperature regulator after the energy storage agent is completely melted, and stir to dissolve;

(2) adding inorganic temperature regulator to the dispersion liquid obtained in step (1), stirring and dissolving;

(3) adding the nucleating agent to the dispersion obtained in step (2) and continuing to stir;

(4) adding thermal conductivity enhancer and distilled water to the dispersion obtained in step (3) and continuing to stir;

(5) Stop the constant temperature heating, add the thickener to the dispersion obtained in step (4) after the temperature is lowered to room temperature, and continue to stir to obtain the phase change material.

The above-mentioned steps, step (1) and step (2) stirring speed are 100-300rpm, stirring time 1-5min; Described organic temperature regulator preferentially adds is conducive to the stability of the system;

The stirring speed of step (3) and step (4) is 6000-8000rpm, and the stirring time is 10-30min;

The nucleating agent in step (3) needs to be dispersed for a longer time, and this approach is conducive to the stability of the subsequent system, so it is preferentially added;

The addition of distilled water in step (4) can supplement part of the crystal water lost during the melting process of sodium sulfate decahydrate, and can appropriately increase the latent heat of phase transition of the system.

In step (5), the dispersion liquid is continuously stirred at 100-300 rpm before being lowered to room temperature. After adding sodium polyacrylate, the stirring rate is 50-100 rpm, and the stirring time is 1-5 min.

The beneficial effect of the invention is that: by adjusting the phase transition temperature of sodium sulfate decahydrate after compounding the three temperature regulators, a composite phase transition material for refrigeration is invented. The phase transition temperature of the material is 1.2-3.0° C. The latent heat is 124-158kJ/kg, the thermal conductivity is greater than 0.7W/m·k, it is not easy to shake during use and creates a good suspension environment for the particle components, and has good thermal conductivity, no phase separation, and high density; The variable material is cheap, environmentally friendly, easy to encapsulate, and has no pollution to water and the environment, and has the prospect of being widely used in the refrigeration and transportation of food and medical products.

Description of drawings

Fig. 1 is the DSC curve diagram of the cold storage material obtained in Example 1;

FIG. 2 is a DSC curve diagram of the cool storage material obtained in Example 2. FIG.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments:

Example 1

A preparation method of a refrigerated phase change cold storage material, comprising the following steps:

(1) 71.74 parts of sodium sulfate decahydrate are placed in a beaker, and the whole is put into a 45°C constant temperature water bath to melt;

(2) 15.2 parts of sodium formate are joined in the sodium sulfate decahydrate that melts completely, start 300rpm to stir 5min;

(3) 3.8 parts of sodium chloride are added in the dispersion of step (2), continue to stir 5min at 300rpm;

(4) 6.65 parts of sodium bromide are added in the dispersion of step (3), continue to stir 5min at 200rpm;

(5) 1.19 parts of sodium tetraborate are added in the dispersion of step (4), continue to stir 30min at 8000rpm;

(6) 0.89 parts of graphite are added to the dispersion of step (5), and continue stirring at 8000rpm for 30min;

(7) 0.23 part of distilled water is added in the dispersion liquid of step (6), continue to stir 8min,;

(8) Stop the constant temperature heating, add 0.3 part of sodium polyacrylate to the dispersion in step (7) after cooling to room temperature, continue stirring at 60 rpm for 5 min, and finally obtain a phase change material.

Figure 1 shows the DSC test chart of the phase change material obtained in this example. It can be seen from the figure that the phase change point of the material is 1.35°C, and the phase change enthalpy is 157.424kJ/kg; after the phase change material in this example is completely solidified At room temperature, an obvious melting phase transition plateau will appear, and the melting plateau temperature is 1.35-3.0 °C.

Example 2

A preparation method of a refrigerated phase change cold storage material, comprising the following steps:

(1) 70.65 parts of sodium sulfate decahydrate are placed in a beaker, and the whole is put into a 45°C constant temperature water bath to melt;

(2) 15.6 parts of sodium formate are joined in the sodium sulfate decahydrate that melts completely, start 300rpm to stir 5min;

(3) 3.5 parts of sodium chloride are added in the dispersion liquid of step (2), continue to stir 5min at 300rpm;

(4) 7.0 parts of sodium bromide are added in the dispersion of step (3), continue to stir 5min at 200rpm;

(5) 2.0 parts of sodium tetraborate are added in the dispersion of step (4), continue to stir 50min at 8000rpm;

(6) 0.7 part of graphite is added in the dispersion liquid of step (5), continue to stir 20min at 8000rpm;

(7) 0.3 part of distilled water is added in the dispersion liquid of step (6), continue stirring 10min,;

(8) Stop constant-temperature heating, add 0.25 part of sodium polyacrylate to the dispersion in step (7) after cooling to room temperature, continue stirring at 50 rpm for 5 min, and finally obtain a phase change material.

Figure 2 shows the DSC test chart of the phase change material obtained in this example. From the figure, it can be seen that the phase change point of the material is 1.201°C, and the phase change enthalpy is 155.427kJ/kg.

Example 3

A preparation method of a refrigerated phase change cold storage material, comprising the following steps:

(1) 70.5 parts of sodium sulfate decahydrate are placed in a beaker, and the whole is put into a 45 ℃ constant temperature water bath to melt;

(2) 16.3 parts of sodium formate are joined in the sodium sulfate decahydrate that melts completely, start 300rpm to stir 5min;

(3) 4 parts of sodium chloride are added in the dispersion of step (2), continue to stir 5min at 300rpm;

(4) 6 parts of sodium bromide are added in the dispersion liquid of step (3), continue to stir 5min at 200rpm;

(5) 1.0 parts of sodium tetraborate are added in the dispersion of step (4), continue to stir 40min at 8000rpm;

(6) 0.9 part of graphite is added in the dispersion liquid of step (5), continue to stir 50min at 8000rpm;

(7) 1 part of distilled water is added in the dispersion liquid of step (6), continue stirring 10min,;

(8) Stop heating at constant temperature, add 0.3 part of sodium polyacrylate to the dispersion in step (7) after cooling to room temperature, continue stirring at 50 rpm for 5 min, and finally obtain a phase change material.

The phase transition point of the material obtained in this example is 1.527°C, and the phase transition enthalpy is 124.579kJ/kg.

Comparative Example 1

Comparative Example 1 is a refrigerated phase change material used in a medical incubator of a cold chain transportation enterprise. The phase change material is composed of n-tetradecane. The thermal conductivity of the phase change material in Comparative Example 1 and Examples 1-3 is compared as follows:

Table 1 Thermal Conductivity Comparison Table

name Example 1 Example 2 Example 3 Comparative Example 1 Thermal conductivity (W/mk) 0.85 0.80 0.85 0.26 Density (g/cm₃) 1.68 1.679 1.67 0.767

The material of Comparative Example 1 and the phase change material obtained in Example 1 were filled into the same cold storage plate, and a charge-discharge cooling cycle was carried out. The phase change material underwent solidification-melting, and the surface condition of the cold storage plate was observed. The surface conditions of the cold storage material packaged cold plate obtained in Example 1 before freezing and after thawing can be seen, the material packaged in Comparative Example 1 had liquid exudates on the surface after the solidification-thaw cycle, while the cold storage plate packaged with the material of Example 1 before and after the cycle. The surface of the cold plate does not change, which fully shows that the phase change material in the present invention has high adaptability to the packaging material, is easier to package than the comparative example, and reduces the possibility of contamination of the transported items caused by the exudation of the phase change material.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, several improvements and modifications can be made. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A refrigeration phase-change cold storage material, characterized in that the phase-change material comprises a phase-change component and an additive, and the phase-change component is composed of 66.15-76.55 parts by mass of energy storage agent, 13.4-17.2 parts of organic temperature regulator and 8.85-13.05 parts by mass of an inorganic temperature regulator, and the additive is composed of 0.5-2.0 parts by mass of a nucleating agent, 0.5-1 parts by mass of a thermal conductivity enhancer, 0.1-0.3 parts by mass of a thickener, and 0.1-0.3 parts by mass of distilled water. 2. The refrigerated phase change cold storage material according to claim 1, wherein the energy storage agent is sodium sulfate decahydrate, the organic temperature regulator is sodium formate, and the nucleating agent is sodium tetraborate. The thermal conductivity enhancer is graphite, and the thickener is sodium polyacrylate. 3. The phase change cold storage material for refrigeration according to claim 1 or 2, wherein the inorganic temperature regulator is composed of 2.85-5.55 parts by mass of sodium chloride and 6-7.5 parts by mass of sodium bromide. 4. A preparation method of a refrigerated phase change cold storage material, characterized in that, comprising the steps: Melt the energy storage agent at a constant temperature of 40-45°C; add an organic temperature regulator after the energy storage agent is completely melted, and stir to dissolve; adding the inorganic temperature regulator to the dispersion obtained in step (1), stirring and dissolving; Add the nucleating agent to the dispersion obtained in step (2) and continue stirring; Add the thermal conductivity enhancer and distilled water to the dispersion obtained in step (3) and continue to stir; The constant temperature heating is stopped, the thickener is added to the dispersion obtained in step (4) after the temperature is lowered to room temperature, and the phase change material is obtained by continuing to stir. 5 . The method for preparing a refrigerated phase change cold storage material according to claim 4 , wherein the stirring speed of step (1) and step (2) is 100-300 rpm, and the stirring time is 1-5 min. 6 . 6 . The method for preparing a refrigerated phase change cold storage material according to claim 4 , wherein the stirring rate of step (3) and step (4) is 6000-8000 rpm, and the stirring time is 10-30 min. 7 . 7 . The method for preparing a phase change cold storage material for refrigeration according to claim 4 or 6 , wherein the nucleating agent needs to be dispersed for a longer time than other components in the additive, and the nucleating agent is added preferentially. 8 . 8 . The method for preparing a refrigerated phase change cold storage material according to claim 4 , characterized in that, in step (5), the dispersion liquid is continuously stirred at 100-300 rpm before being lowered to room temperature. 9 . 9 . The method for preparing a refrigerated phase change cold storage material according to claim 4 , characterized in that, after adding sodium polyacrylate in step (5), the stirring rate is 50-100 rpm, and the stirring time is 1-5 min. 10 .

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