CN104371658A - Packaging shape-stabilizing method of inorganic hydrated salt phase-change heat storage material - Google Patents

Abstract

The invention provides a packaging shape-stabilizing method of an inorganic hydrated salt phase-change heat storage material, which comprises the following steps: (1) adding a nucleator and deionized water into the inorganic hydrated salt phase-change material, and heating until the inorganic hydrated salt phase-change material achieves the molten state; (2) adding a porous propping material into the molten-state inorganic hydrated salt phase-change material, and stirring sufficiently and uniformly; (3) putting the molten-state mixture obtained in the step (2) in a vacuum environment to enhance the adsorptivity of the porous propping material for the inorganic hydrated salt phase-change material; and (4) moving the molten-state mixture out of the vacuum environment, and immediately putting the molten-state mixture into a low-temperature environment suitable for crystallization to perform recrystallization. The composite shape-stabilized phase-change material obtained by the method has the advantages of stable structure, high latent heat, no toxicity, simple preparation process, short time consumption and low cost.

Description

Encapsulation and shaping method of inorganic hydrated salt phase change heat storage material

technical field

The invention relates to the field of material science and technology, in particular to a packaging and shaping method for an inorganic hydrated salt phase-change heat storage material.

Background technique

Phase change materials have the advantages of high heat storage density, small volume of heat storage container, high heat storage efficiency, constant phase change temperature and recyclable use. Recycling and other fields have broad application prospects. As an important phase change energy storage material at normal and low temperature, inorganic hydrate salt has the characteristics of fixed phase change temperature, high phase change latent heat, good thermal conductivity and low price. However, this solid-liquid phase change material will undergo solid-liquid changes during the phase change process, and has defects in liquid fluidity and easy leakage, as well as certain supercooling and phase separation phenomena, so its application in production and life is limited. widely used.

At present, the methods to solve the leakage problem of phase change materials mainly include porous material adsorption method and microcapsule encapsulation method. For example, Chinese patent 200810048159.5 describes a method for obtaining a porous composite inorganic phase change material. In addition, Chinese patent 201210136116 describes an inorganic hydrated salt phase change energy storage microcapsule and its preparation method. This microcapsule method can effectively solve the problems of supercooling and phase separation of the hydrated salt phase change material. Although the above methods all solve the leakage problem of the phase change material, the preparation process takes a long time, and there are problems of incomplete and uneven adsorption.

Contents of the invention

In order to improve the energy storage stability of the composite shape-setting phase change material, prevent leakage during the phase change process, and improve the thermal conductivity of the phase change material, the present invention provides a packaging and setting method for an inorganic hydrated salt phase change heat storage material. At the same time, the capillary adsorption performance of porous materials is used to solve the problem of its easy leakage, and the vacuum impregnation method is used to strengthen the adsorption, thereby improving its comprehensive performance. The composite shape-setting phase-change material obtained by the invention has stable structure, large latent heat, non-toxicity, simple preparation process, short time consumption and low cost.

A method for encapsulating and shaping an inorganic hydrated salt phase-change heat storage material, said method comprising the following steps:

(1) Add nucleating agent and deionized water to the inorganic hydrated salt phase change material and heat to make the inorganic hydrated salt phase change material reach a molten state; (2) Add porous support materials to the molten inorganic hydrated salt phase change (3) Put the molten mixture obtained in step (2) in a vacuum environment to strengthen the adsorption of the porous support material to the inorganic hydrate salt phase change material; (4) Put the molten mixture from the vacuum environment Remove it, and immediately place it in a low temperature environment suitable for crystallization for recrystallization. Wherein, in the mixture composed of inorganic hydrated salt phase change material, nucleating agent and porous support material, the proportion of inorganic hydrated salt phase change material is 52-70wt%, and the proportion of nucleating agent is 1-2wt%, The proportion of porous support materials is 28-47wt%, and the sum of the three is 100%.

The inorganic hydrated salt phase change material is Na ₂ SO ₄ ·10H ₂ O, CaCl ₂ ·6H ₂ O, KF·2H ₂ O, KF·4H ₂ O, MgCl ₂ ·4H ₂ O, Mg(NO ₃ ) ₂ 6H ₂ O, MgSO ₄ , 7H ₂ O, Na ₂ HPO ₄ , 12H ₂ O, Na ₂ CO ₃ , 10H ₂ O, CH ₃ COONa 3H ₂ O, LiNO3 3H ₂ O, LiClO ₃ 3H ₂ O one or more of them.

The nucleating agent is one or more of borax, strontium chloride hexahydrate, magnesium chloride hexahydrate, and barium carbonate.

 The porous support material is expanded perlite, expanded graphite, expanded vermiculite, porous alumina or porous activated carbon.

Description of drawings

Figure 1a, Figure 1b, Figure 1c, and Figure 1d are SEM photos of CaCl ₂ ·6H ₂ O porous alumina composite phase change materials;

Figure 2a, Figure 2b, Figure 2c, and Figure 2d are the DSC curves of the CaCl ₂ ·6H ₂ O porous alumina composite phase change material.

Detailed ways

Below utilize embodiment to further describe the present invention in detail.

Example 1:

(1) Take 2g CaCl ₂ 6H ₂ O, put it in a beaker, add 0.06 borax, mix evenly, add a small amount of deionized water, seal it with plastic wrap, put it in a constant temperature drying oven at 50 ℃, and heat it for 5 minutes. Make it into a molten state; (2) Take 1.0 g of porous Al ₂ O ₃ and add it to a beaker filled with molten CaCl ₂ 6H ₂ O, and stir evenly, put the beaker of the above sample into a vacuum drying oven, and vacuum 2h, and then placed in the refrigerator for 5h for recrystallization, and a novel CaCl ₂ 6H ₂ O porous Al ₂ O ₃ composite phase change material with uniform adsorption was obtained; (3) The phase transition temperature of the obtained composite shape-fixed phase change heat storage material was 30.71 °C, the latent heat value of phase transition is 99.81 J/g; the SEM photos and DSC test results of this example are shown in Figure 1a and Figure 2a, respectively.

Example 2:

(1) Take 2g CaCl ₂ 6H ₂ O, put it in a beaker, add 0.06 borax, mix well, add a small amount of deionized water, seal it with plastic wrap, put it in a constant temperature drying oven at 50 ℃, and heat it for 5 minutes. Make it into a molten state; (2) Take 1.2 g of porous Al ₂ O ₃ and add it to a beaker filled with molten CaCl ₂ 6H ₂ O, and stir evenly, put the beaker of the above sample into a vacuum drying oven, and vacuum 2h, and then placed in the refrigerator for 5h for recrystallization, and a novel CaCl ₂ 6H ₂ O porous Al ₂ O ₃ composite phase change material with uniform adsorption was obtained; (3) The phase transition temperature of the obtained composite shape-fixed phase change heat storage material was 29.95 °C, the latent heat value of phase transition is 86.42 J/g; the SEM photos and DSC test results of this example are shown in Figure 1b and Figure 2b, respectively.

Example 3:

(1) Take 2g CaCl ₂ 6H ₂ O, put it in a beaker, add 0.06 borax, mix evenly, add a small amount of deionized water, seal it with plastic wrap, put it in a constant temperature drying oven at 50 ℃, and heat it for 5 minutes , so that it reaches a molten state; (2) Take 1.4 porous Al ₂ O ₃ and add it to a beaker filled with molten CaCl ₂ 6H ₂ O, and stir evenly. Put the beaker of the above sample into a vacuum oven, and pump Vacuum for 2 hours, and then put it in the refrigerator for 5 hours to recrystallize, and obtain a new CaCl ₂ ·6H ₂ O porous Al ₂ O ₃ composite phase change material with uniform adsorption; (3) The phase change temperature of the obtained composite shape-fixed phase change heat storage material is 28.34°C, the latent heat value of phase transition is 70.61J/; the SEM photos and DSC test results of this example are shown in Figure 1c and Figure 2c, respectively.

Example 4:

(1) Take 2g CaCl ₂ 6H ₂ O, put it in a beaker, add 0.06 borax, mix well, add a small amount of deionized water, seal it with plastic wrap, put it in a constant temperature drying oven at 50 ℃, and heat it for 5 minutes , so that it reaches a molten state; (2) Take 1.6 porous Al ₂ O ₃ and add it to a beaker filled with molten CaCl ₂ 6H ₂ O, and stir evenly, put the beaker of the above sample into a vacuum oven, and pump Vacuum for 2 hours, and then put it in the refrigerator for 5 hours to recrystallize, and obtain a new CaCl ₂ ·6H ₂ O porous Al ₂ O ₃ composite phase change material with uniform adsorption; (3) The phase change temperature of the obtained composite shape-fixed phase change heat storage material is 27.71°C, the latent heat value of phase transition is 60.58J/g; the SEM photos and DSC test results of this example are shown in Figure 1d and Figure 2d respectively.

The above only cites the examples of using CaCl ₂ ·6H ₂ O as the phase change material, borax as the nucleating agent, and porous Al ₂ O ₃ as the supporting material. agent, supporting material can realize the present invention, and can obtain corresponding effect.

the

Claims (7)

1. A method for encapsulating and shaping an inorganic hydrated salt phase-change heat storage material, said method comprising the steps of: (1) Adding a nucleating agent and deionized water to the inorganic hydrated salt phase change material and heating, so that the inorganic hydrated salt phase change material reaches a molten state; (2) Add the porous support material to the molten inorganic hydrated salt phase change material, and stir well; (3) placing the molten mixture obtained in step (2) in a vacuum environment to strengthen the adsorption of the porous support material on the inorganic hydrated salt phase change material; (4) Remove the molten mixture from the vacuum environment, and immediately place it in a low temperature environment suitable for crystallization for recrystallization. 2. The method according to claim 1, wherein the inorganic hydrated salt phase change material is Na ₂ SO ₄ ·10H ₂ O, CaCl ₂ ·6H ₂ O, KF·2H ₂ O, KF·4H ₂ O, MgCl ₂ 4H ₂ O, Mg(NO ₃ ) ₂ 6H ₂ O, MgSO ₄ 7H ₂ O, Na ₂ HPO ₄ 12H ₂ O, Na ₂ CO ₃ 10H ₂ O, CH ₃ COONa 3H ₂ O, One or more of LiNO3·3H ₂ O and LiClO ₃ ·3H ₂ O. 3. The method according to claim 1, wherein the nucleating agent is one or more of borax, strontium chloride hexahydrate, magnesium chloride hexahydrate, and barium carbonate. 4. The method of claim 1, wherein the porous support material is expanded perlite, expanded graphite, expanded vermiculite, porous alumina, or porous activated carbon. 5. The method according to claim 1, wherein, in the mixture composed of inorganic hydrated salt phase change material, nucleating agent and porous support material, the proportion of inorganic hydrated salt phase change material is 52-70wt%, forming The proportion of the nucleating agent is 1-2wt%, the proportion of the porous support material is 28-47wt%, and the sum of the three is 100%. 6. The method according to any one of claims 1-5, wherein the time for placing the molten mixture under a vacuum environment is at least 2 hours. 7. The method according to any one of claims 1-5, wherein the time for recrystallization under a low temperature environment suitable for crystallization is at least 5 hours.