A kind of composite phase change material and its preparation method and application

Abstract

The invention provides a compound made of disodium hydrogen phosphate dodecahydrate and capric acid in a mass ratio of 8:2 to 6:4, adding a thickener of 0.5%-1.5% of the total mass and adopting a sol-gel method. Phase change material, its phase change temperature is 23.8°C-24.8°C, the degree of supercooling is 0.9°C-2.2°C, the latent heat value of phase change is 139.6-168.3J / g, and the thermal conductivity is 0.453-0.502W / m·K; The invention also provides a preparation method and application of the composite phase change material. The preparation method includes melting capric acid, making a sol in a reactor with disodium hydrogen phosphate dodecahydrate and capric acid, adding a thickener and aging to form a sol. Glue, placed in a programmable high and low temperature alternating box for 300-350 times of cold and hot cycles to prepare a low-cost composite phase change material with suitable phase transition temperature, large thermal conductivity, high phase transition latent heat value, and stable performance; the composite phase The concrete slabs produced by adding variable materials into concrete have good heat storage and energy-saving effects; compared with existing technologies such as adding porous materials, nanomaterials, and new packaging techniques, the present invention has a simple process and is easy to operate, and is widely used in energy-saving buildings field.

Description

technical field [0001] The invention belongs to material technology, and in particular relates to a composite phase change material and its preparation method and application. Background technique [0002] Heat storage technology plays an important role in the field of energy science. Phase change materials can efficiently absorb or release heat through phase change to greatly improve energy storage performance, and have the advantages of small volume change, constant phase change temperature, safety and environmental protection. Utilization, building materials, aerospace, equipment industry, low-temperature transportation and other fields have been extensively studied. [0003] At present, solid-liquid phase change materials are the most common type of phase change materials due to their small volume change and easy control. They can be divided into inorganic phase change materials and organic phase change materials. The advantages of inorganic phase change materials are l...

AI Technical Summary

Problems solved by technology

The advantages of inorganic phase change materials are low cost, relatively high phase change latent heat and thermal conductivity, but there are problems of supercooling and phase separation. Traditionally, the problems of supercooling and separation are solved by adding nucleating agents and thickeners. However, the stability of the thickener is poor and it is difficult to accurately control the amount of addition, so it is necessary to explore the modification method of new inorganic hydrated salts

The advantage of organic phase change materials is that there is no supercooling and phase separation, but they have defects such as too small thermal conductivity and flammability.

In recent years, research at home and abroad has mainly improved phase change materials by adding porous materials, adding nanomaterials, and new packaging technologies. However, the actual application of phase change materials in energy-saving buildings has limited the application of phase change materials due to high manufacturing costs and technical difficulties.

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