阅读说明：本技术 一种中空相变储能陶粒及其制备方法 (Hollow phase change energy storage ceramsite and preparation method thereof ) 是由 郑伍魁 李辉 王飞 杨雨玄 朱毅 于 2021-02-04 设计创作，主要内容包括：本发明公开了一种中空相变储能陶粒及其制备方法,涉及相变储能材料技术领域。本发明的制备方法为：通过抽真空抽出中空陶粒内部孔隙和空腔中的空气,然后在真空环境下将中空陶粒浸泡在有机相变物质中,持续浸泡30-40min即可得到相变储能陶粒。本发明的储能陶粒无需进行二次包装处理,具有强度高、储存量大、泄漏率低、相变换热效率高等特点,同时制备方法简单,能够满足建筑领域的应用,具有重要的工业化生产意义。(The invention discloses a hollow phase-change energy-storage ceramsite and a preparation method thereof, and relates to the technical field of phase-change energy-storage materials. The preparation method comprises the following steps: and vacuumizing to extract air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material in a vacuum environment for 30-40min to obtain the phase change energy storage ceramsite. The energy storage ceramsite disclosed by the invention does not need to be subjected to secondary packaging treatment, has the characteristics of high strength, large storage capacity, low leakage rate, high phase-change heat exchange efficiency and the like, is simple in preparation method, can meet the application in the field of buildings, and has important industrial production significance.)

1. The phase change energy storage ceramsite is characterized in that hollow ceramsite is used as a base body, and an organic phase change material is stored in a hollow cavity of the base body;

the hollow cavity of the hollow ceramsite accounts for 40-50% of the total volume of the hollow ceramsite.

2. The phase-change energy-storage ceramsite according to claim 1, wherein the matrix comprises fly ash, copper slag or coal gangue.

3. The phase-change energy storage ceramsite according to claim 1, wherein the organic phase-change material comprises paraffin, fatty acid and derivatives thereof.

4. The method for preparing phase-change energy storage ceramsite as claimed in any one of claims 1-3, wherein the hollow ceramsite is made to adsorb organic phase-change materials by vacuum impregnation.

5. The method for preparing the phase-change energy-storage ceramsite according to claim 4, wherein the method comprises the following steps:

and vacuumizing to exhaust air in the inner pores and cavities of the hollow ceramsite, and soaking the hollow ceramsite in the organic phase change material in a vacuum environment for 30-40 min.

6. The method for preparing phase-change energy-storage ceramsite according to claim 5, wherein the pressure of the vacuum environment is-0.093 to-0.097 MPa, and the temperature is 25-70 ℃.

7. The method for preparing phase-change energy-storage ceramsite according to claim 5, wherein the method further comprises the step of drying and heating the hollow ceramsite before soaking.

8. The method for preparing phase-change energy-storage ceramsite according to claim 7, wherein the heating temperature is 30-70 ℃.

Technical Field

The invention relates to the technical field of phase change energy storage materials, in particular to hollow phase change energy storage ceramsite and a preparation method thereof.

Background

In recent years, building energy consumption accounts for about one third of the total world energy consumption, with more than half of the energy consumption coming from space cooling and heating control. Therefore, some energy saving techniques should be adopted to reduce energy consumption. Many researchers have pointed out that heat storage plays an important role in regulating indoor temperature, transferring peak load to valley load, reducing space cooling and heating energy consumption, and the like. Phase Change Materials (PCMs) have good heat storage capacity and a narrow temperature variation range during phase change, and thus have attracted much attention. At present, the combination of building components and PCM becomes an effective way in the field of building energy conservation.

However, the effective integration of PCMs with building components is a challenging issue. At present, the organic solid-liquid PCM is widely applied to building envelope structures due to the advantages of large latent heat, small volume change, stable performance and the like. However, if the PCM is directly combined with a construction material, the solid-liquid PCM may leak during the phase change. This phenomenon affects not only the thermal efficiency of the PCM but also the mechanical properties and durability of the building material. Therefore, in order to solve the leakage problem, various encapsulation technologies, such as a microcapsule encapsulation technology, a macro-encapsulation technology, and a porous material adsorption technology, have been studied.

Compared with microcapsule encapsulation technology and macro-encapsulation technology, porous material adsorption technology is increasingly paid more attention by people due to the advantages of simple process, low price and the like. Porous materials for adsorbing PCM are generally classified into clay-based mineral materials and ceramic aggregates. However, clay mineral based phase change materials added directly to concrete mixes are often not optimally selected because they are not uniformly dispersed and the PCM adhered to the surface may interfere with the hydration product. The ceramsite adsorption technology is widely researched because the ceramsite adsorption technology can be more effectively and conveniently combined with building materials.

Many researchers have utilized capillary forces, hydrogen bonding, and van der waals forces to produce high porosity ceramic composite materials. Zhang et al prepared energy storage concrete by doping PCM into porous ceramsite, the maximum percentage of PCM absorbed by porous ceramsite was 68%, and the prepared composite phase change material had a large heat storage density and was suitable for large-scale processing. Menmon et al prepared a paraffin/ceramsite aggregate for functional concrete, and indoor thermal performance tests showed that the paraffin/ceramsite concrete has the effects of reducing temperature fluctuation and reducing energy consumption.

However, there are still many problems to be solved. For example, (a) high porosity ceramsite generally corresponds to low strength and a loose granular structure, which limits the strength of concrete. Yang provides a lightweight aggregate composite PCM applied to a building envelope structure. 6 pieces of phase-change concrete with different mass fractions are prepared according to the concrete production standard, the maximum compressive stress is 0.54MPa, and when the mass fraction of the phase-change ceramsite is 20%, the compressive strength is reduced by nearly 30%. (b) The PCM that is sucked into the ceramic particles by the vacuum adsorption method is easy to leak, and a coating is required to prevent the leakage. This phenomenon was found in the test of Cui, and the sealing performance of lightweight aggregates was evaluated by measuring the mass loss of the test specimens. The result shows that after 150 times of thermal cycles, the mass loss rate of the uncoated phase-change aggregate is about 25 percent; the mass loss rate of the phase-change ceramsite coated by the epoxy resin is about 0.81 percent. In Menmon's study, paraffin/ceramsite was modified epoxy coated. The effectiveness of the encapsulation was determined by leak testing and the results indicated that the amount of leakage was less than 5%.

However, although the epoxy ceramsite coating can prevent leakage, the technology also brings new problems, such as complicated preparation process, low thermal conductivity and poor interface compatibility. Therefore, in order to more conveniently and effectively apply PCM to building envelopes, it is necessary to develop a novel carrier having higher strength, better storage capacity and low leakage rate without the need of a coating.

Disclosure of Invention

The invention aims to provide a hollow phase-change energy-storage ceramsite and a preparation method thereof, which are used for solving the problems in the prior art, so that the phase-change energy-storage ceramsite has high strength, good storage capacity, no need of secondary encapsulation, wide material source, low cost and simple operation.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides phase change energy storage ceramsite, which takes hollow ceramsite as a matrix, wherein an organic phase change material is stored in the hollow cavity of the matrix;

the hollow cavity of the hollow ceramsite accounts for 40-50% of the total volume of the hollow ceramsite.

Further, the substrate comprises fly ash, copper slag or coal gangue.

Further, the organic phase change material includes paraffin, fatty acid and derivatives thereof.

The invention also provides a preparation method of the phase change energy storage ceramsite, which adopts a vacuum impregnation method to make the hollow ceramsite adsorb the organic phase change material.

Further, the preparation method comprises the following steps:

and vacuumizing to exhaust air in the inner pores and cavities of the hollow ceramsite, and soaking the hollow ceramsite in the organic phase change material in a vacuum environment for 30-40 min.

Furthermore, the pressure of the vacuum environment is-0.093 to-0.097 MPa, and the temperature is 25-70 ℃.

Further, before soaking, the method also comprises the steps of drying and heating the hollow ceramsite.

Further, the heating temperature is 30-70 ℃.

The heating temperature condition can prevent rapid cooling caused by the temperature of the matrix being lower than that of the phase-change material, thereby blocking the holes and reducing the entering of the phase-change material.

The invention discloses the following technical effects:

the invention adopts the hollow ceramsite to load the phase-change material to prepare the phase-change energy-storage ceramsite, and mainly achieves the following three technical effects: (1) the phase change energy storage ceramsite has high strength; (2) the phase change energy storage ceramsite has large adsorption capacity; (3) the leakage rate of the phase change energy storage ceramsite is small.

Compared with the common high-porosity ceramsite, the hollow ceramsite does not need to sacrifice the strength of the hollow ceramsite in order to meet the requirement of high porosity; the hollow cavity inside the hollow ceramsite can store more phase change substances by a vacuum adsorption technology; more importantly, the original permeation mode of the PCM in the porcelain granules is changed in the inner cavity of the hollow porcelain granules, and the leakage rate of the phase-change material can be reduced by controlling the shell wall of the hollow porcelain granules.

The novel hollow ceramsite prepared by the invention can be directly used for building structures without secondary packaging treatment, and provides a self-adaptive thought for application of PCM in buildings. Can be directly used as aggregate, realizes long-term stable storage, reduces construction process, and increases the compatibility between the phase-change ceramsite and the concrete matrix.

Meanwhile, the material of the invention has wide source, low price and simple preparation method, can realize the mass production of the energy storage ceramsite, and has important industrial production significance.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a flow chart of the preparation of the hollow ceramsite and the phase-change ceramsite of the present invention;

FIG. 2 is a diagram illustrating the preparation of hollow ceramsite and phase-change ceramsite according to the present invention;

wherein, (1) is a balling disk; (2) is a muffle furnace; (3) is a vacuum adsorption device;

FIG. 3 is a diagram of a hollow phase-change energy-storage ceramsite prepared in example 1 of the present invention.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The "parts" in the present invention are all parts by mass unless otherwise specified.

The flow chart of the preparation process of the hollow ceramsite and the phase-change ceramsite is shown in figure 1; the preparation diagram of the hollow ceramsite and the phase-change ceramsite is shown in figure 2.

The sintering temperature of the hollow ceramsite directly determines the leakage rate of the product, and the invention adopts the hollow ceramsite with the sintering temperature of 1100-1200 ℃.

Example 1

The fly ash hollow ceramsite with the sintering temperature of 1100 ℃ is adopted to store the organic phase change material, the diameter of the ceramsite is 11.23mm, the diameter of an inner cavity is 5.6mm, and the shape of the ceramsite is approximately spherical.

Paraffin with the melting point of 29 ℃ and the phase change enthalpy of 224.5J/g is selected as the organic phase change substance.

The preparation method comprises the following steps:

and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 30min under the conditions that the vacuum pressure is-0.095 MPa and the temperature is 70 ℃ to obtain the hollow phase change energy storage ceramsite.

And after soaking, detecting that the storage capacity of the organic phase change material is 40% of the mass of the hollow phase change energy storage ceramsite.

The physical diagram of the prepared hollow phase-change energy-storage ceramsite is shown in figure 3.

Example 2

The copper slag hollow ceramsite with the sintering temperature of 1150 ℃ is adopted to store the organic phase change material, the diameter of the ceramsite is 10mm, the diameter of an inner cavity is 4.5mm, and the shape of the ceramsite is approximately spherical.

The slice paraffin with the melting point of 65 ℃ and the phase change enthalpy of 224.5J/g is selected as the organic phase change material.

The preparation method comprises the following steps:

and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 40min under the conditions that the vacuum pressure is-0.095 MPa and the temperature is 70 ℃ to obtain the hollow phase change energy storage ceramsite.

And after soaking, detecting that the storage capacity of the organic phase change material is 32% of the mass of the hollow phase change energy storage ceramsite.

Example 3

The coal gangue hollow ceramsite with the sintering temperature of 1200 ℃ is adopted to store the organic phase change material, the diameter of the ceramsite is 10.2mm, the diameter of an inner cavity is 4.3mm, and the shape of the ceramsite is approximately spherical.

The slice paraffin with the melting point of 65 ℃ and the phase change enthalpy of 224.5J/g is selected as the organic phase change material.

The preparation method comprises the following steps:

and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 35min under the conditions that the vacuum pressure is-0.093 MPa and the temperature is 70 ℃ to obtain the hollow phase change energy storage ceramsite.

After soaking, detecting that the storage capacity of the organic phase change material is 35% of the quality of the hollow phase change energy storage ceramsite.

Example 4

The fly ash hollow ceramsite with the sintering temperature of 1100 ℃ is adopted to store the organic phase change material, the diameter of the ceramsite is 10mm, the diameter of an inner cavity is 5mm, and the shape of the ceramsite is approximately spherical.

N-tetradecane with the melting point of 29 ℃ and the phase-change enthalpy of 204.5J/g is selected as the organic phase-change substance.

The preparation method comprises the following steps:

and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 38min under the conditions that the vacuum pressure is-0.097 MPa and the temperature is 35 ℃ to obtain the hollow phase change energy storage ceramsite.

And after soaking, detecting that the storage capacity of the organic phase change material is 46% of the mass of the hollow phase change energy storage ceramsite.

Example 5

The fly ash hollow ceramsite with the sintering temperature of 1150 ℃ is used for storing the organic phase change material, the diameter of the ceramsite is 10.3mm, the diameter of an inner cavity is 4.3mm, and the shape of the ceramsite is approximately spherical.

N-tetradecane with the melting point of 29 ℃ and the phase-change enthalpy of 204.5J/g is selected as the organic phase-change substance.

The preparation method comprises the following steps:

(1) drying the hollow ceramsite and heating the hollow ceramsite to 30 ℃;

(2) and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 38min under the conditions that the vacuum pressure is-0.094 MPa and the temperature is 32 ℃ to obtain the hollow phase change energy storage ceramsite.

And after soaking, detecting that the storage capacity of the organic phase change material is 42% of the mass of the hollow phase change energy storage ceramsite.

Example 6

The fly ash hollow ceramsite with the sintering temperature of 1200 ℃ is used for storing the organic phase change material, the diameter of the ceramsite is 10.2mm, the diameter of an inner cavity is 4.5mm, and the shape of the ceramsite is approximately spherical.

N-tetradecane with the melting point of 29 ℃ and the phase-change enthalpy of 204.5J/g is selected as the organic phase-change substance.

The preparation method comprises the following steps:

(1) drying the hollow ceramsite and heating the hollow ceramsite to 70 ℃;

(2) and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 38min under the conditions that the vacuum pressure is-0.093 MPa and the temperature is 32 ℃ to obtain the hollow phase change energy storage ceramsite.

After soaking, detecting that the storage capacity of the organic phase change material is 47% of the mass of the hollow phase change energy storage ceramsite.

Example 7

The fly ash hollow ceramsite with the sintering temperature of 1200 ℃ is used for storing the organic phase change material, the diameter of the ceramsite is 10.2mm, the diameter of an inner cavity is 4.3mm, and the shape of the ceramsite is approximately spherical.

N-tetradecane with the melting point of 29 ℃ and the phase-change enthalpy of 204.5J/g is selected as the organic phase-change substance.

The preparation method comprises the following steps:

(1) drying the hollow ceramsite and heating the hollow ceramsite to 55 ℃;

(2) and vacuumizing to pump out air in the inner pores and cavities of the hollow ceramsite, and then soaking the hollow ceramsite in the organic phase change material for 36min under the conditions that the vacuum pressure is-0.094 MPa and the temperature is 32 ℃ to obtain the hollow phase change energy storage ceramsite.

After soaking, detecting that the storage capacity of the organic phase change material is 45% of the mass of the hollow phase change energy storage ceramsite.

Comparative example 1

The difference from the embodiment 1 is only that the fly ash matrix hollow ceramsite is replaced by the fly ash matrix porous structure ceramsite with the same size.

Comparative example 2

The difference from the embodiment 1 is only that the diameter of the inner cavity of the ceramsite is 9.5mm, and the diameter of the inner cavity is 5.6 mm.

Comparative example 3

The only difference from example 4 was that n-tetradecane was replaced with lauric acid.

Comparative example 4

The only difference from example 4 is that n-tetradecane is replaced by decanoic acid.

The physical properties and the thermal properties of the hollow phase change energy storage ceramsite prepared in the embodiments 1-6 and the comparative examples 1-4 of the invention are shown in the table 1.

TABLE 1

Note: the leakage rate in table 1 was measured by 200 phase change cycle tests.

Phase change cycle test operation: and (3) putting the hollow energy storage ceramsite into a 40 ℃ oven, taking out the hollow energy storage ceramsite after 4 hours, and then putting the hollow energy storage ceramsite into 10 ℃ air for cooling to complete a cycle process.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.