KR20070029311A - Porous material for latent heat and accumulated heat and method for producing the same - Google Patents

Abstract

Provided are a porous material for latent heat and accumulated heat, which is useful as a heat storage/supply medium with higher efficiency and prevents leakage of a phase change material by impregnating a fluid phase change material into porous clay or pearlite, and a method for producing the same. The porous material for latent heat and accumulated heat is produced by the method comprising impregnating a phase change material(PCM) into a porous material by a pressure impregnation technology. Preferably, the phase change material(PCM) is a paraffinic material and the porous material is selected from porous clay or porous pearlite. The pressure impregnation is preferably performed under a condition of heat having a temperature above a melting point of PCM and a pressure of 40-100 kPa.

Description

Porous latent heat storage material and method for producing the same {Porous material for latent heat and accumulated heat and method for producing the same}

1 is a view showing an autoclave to which the pressure impregnation method of the present invention is applied

The present invention relates to a porous latent heat storage material which can be used as a heat storage and heat supply medium by impregnating a fluid paraffinic phase change material (PCM) into a porous material such as porous clay or perlite. It relates to a manufacturing method.

PCM refers to the heat-absorption, heating, It is used in the life industry of heat sink, clothing, food industry, etc.

The most widely used materials for PCM are organic compounds such as salts, salts or mixtures thereof, and paraffin. It is largely divided into organic and inorganic materials. Organic materials are generally low in density and low in latent heat, but they are less corrosive and have smaller volume expansion than inorganic PCM. In contrast, inorganic materials have a disadvantage in that they are difficult to package due to their high density and high latent heat, but high corrosiveness and large volume expansion.

The conditions of PCM for axial heat dissipation system are suitable phase change temperature, high latent heat density and heat transfer rate, phase equilibrium, low gas pressure, small volume expansion rate, high density, no supercooling, high crystal growth rate, chemical stability, low corrosiveness, Material purchase should be easy and cheap.

Paraffin-based PCM, which satisfies the above conditions and has a very low unit cost, is widely used as a latent heat storage material. Conventional encapsulation technology of a phase change material is a method of microencapsulating with melamine or formaldehyde resin, and this method has not been put to practical use because the process is complicated and increases the manufacturing cost.

Accordingly, an object of the present invention is to provide a porous latent heat storage material and a method for manufacturing the same, which can be inexpensive latent heat storage material by a simple process by impregnating PCM in a porous material such as low price porous clay or perlite. I have a problem.

The present invention relates to a porous latent heat storage material and a method for producing the same, which are capable of suppressing the outflow of PCM by capillary effect by pressurizing and impregnating PCM in a porous material such as porous clay or pearlite, and having excellent thermal response and thermal conductivity. will be.

Hereinafter, the present invention will be described in more detail.

The present invention uses a paraffinic PCM (melting point 0 ℃ ~ 130 ℃) and a porous material (porosity: 30% to 80%), such as porous clay or pearlite, paraffin-based PCM porous material (particle diameter: 1 ~ 10mm) It relates to a latent heat storage material prepared by impregnating into the micropores of (pore size: 10 ~ 100㎛) and its manufacturing method.

The paraffinic PCM may have a melting point of 0 ° C. to 130 ° C. depending on the number of carbon atoms, and it is preferable to select a PCM having a melting point of 30 ° C. to 50 ° C.

The porous material is preferably selected from clay or pearlite, and the porosity of the porous material is suitably in the range of 30% to 80%. If the porosity is less than 30%, the PCM impregnation amount is low, so the heat storage effect is low, and if the porosity exceeds 80%, there may be leakage of PCM.

The pore size of the porous material is preferably in the range of 10 ~ 100㎛. If the pore size is less than 10 μm, the impregnation time is long, and if the pore size exceeds 100 μm, there is a risk of leakage.

The particle size of the porous material is preferably in the range of 1 ~ 10mm. Porous materials with a particle size of 1 to 10 mm have a large cross section, which can compensate for the low thermal conductivity of PCM.

1 is a view showing an autoclave for applying the pressure impregnation method of the present invention. Porous material 3 such as porous clay or pearlite is placed inside the lower flask, and the PCM 2 is filled inside the upper flask. The autoclave 1 serves to impregnate the PCM 2 by applying heat and pressure. Immersion time is about 30 minutes and pressure is about 80 kPa. When the temperature begins to rise above the melting point of the paraffinic PCM material, the PCM (2) begins to melt and the PCM solution begins to enter the porous material (3) under the pressure of the autoclave. The PCM solution under constant pressure penetrates between the micropores of the porous material 3. After pressing for 30 minutes, the porous material is washed and, if necessary, the temperature is raised above the PCM melting point to remove the PCM attached to the surface of the porous material.

In this way, paraffin-based PCM is filled in the micropores of porous materials such as porous clay or pearlite to complete the porous latent heat storage material.

<Example>

Clay or pearlite having a porosity of 50%, a particle diameter of 8 mm and a micropore size of 80 μm is filled into the lower flask and paraffin-based PCM is placed in the upper flask. To impart fluidity of the PCM material, heat above the melting point and a pressure of about 80 kPa are applied and the PCM is impregnated for 30 minutes. Thereafter, the porous material was washed and, if necessary, the temperature was raised above the PCM melting point in order to remove the PCM attached to the surface of the porous material, and then washed.

Comparative Example

The same process as in <Example> was carried out except that impregnation was carried out at normal pressure without pressure.

After preparing the latent heat storage material of porous clay or pearlite by the method of Examples and Comparative Examples, the content of impregnated PCM was investigated. The examples were 43% impregnated for porous clay and 51% impregnated for porous pearlite. In the comparative example, 17% of porous clay and 38% of porous pearlite were impregnated.

(The above percentage is the ratio of the impregnated weight of PCM to the total weight of the porous material.)

TABLE 1

The graph below shows the endothermic and exothermic phenomenon of the latent heat storage material produced by the above method.

<Graph 1>

<Graph 2>

<Graph 1> is an endothermic and exothermic curve of latent heat storage material impregnated with paraffinic PCM in porous clay. In the graph above, melting point is 48.56 ℃, latent heat is 24.98 J / g, and <Graph 2> is endothermic and exothermic curve of latent heat storage material impregnated with PCM in porous pearlite, and melting point is 49.83 ℃ and latent heat is 33.86 J / g. .

In the case of porous perlite, since the micropores of the material are more than that of clay, about 50% of the PCM may be impregnated, which shows that the latent heat is greater than that of the clay.

The present invention enables the application as a latent heat storage material for thermal insulation and heating by impregnating paraffin-based PCM in porous clay or pearlite through a pressure impregnation method. In addition, the present invention, unlike the conventional microcapsule method, the process is simple, mass production is possible, and the thermal response speed is high and the thermal conductivity is high by the porous structure, and the impregnated amount of PCM can be increased compared to the microcapsule method, and thus the latent heat for energy saving. There is an advantage to widen the application range to the heat storage material.

Claims (6)

Method for producing a porous latent heat storage material, characterized in that by impregnating a phase change material (PCM) in a porous material using a pressure impregnation method. The method of claim 1, wherein the phase change material (PCM) is a paraffin-based material. The method of claim 1, wherein the porous material is selected from porous clay or porous pearlite. The method of claim 1, wherein the pressure impregnation conditions are heat above the melting point of the PCM and pressure of 40 ~ 100kPa. Porous latent heat storage material prepared by the method of claim 1. The porous latent heat storage material according to claim 5, wherein the porous material has a pore size of 10 to 100 µm, a porosity of 30 to 80%, and a particle diameter of 1 to 10 mm.

Images