Phase change insulation structure for permanent insulation of concrete structures

Abstract

The present invention provides a phase-change insulation structure for permanent thermal insulation of concrete structures. The structure comprises a PCM inner layer, a PCM outer layer, and an insulation material layer. The PCM inner layer adheres closely to the concrete structure, protecting it from sudden temperature drops during seasonal changes. The PCM outer layer overlies the inner layer, protecting it from winter cold snaps and large diurnal temperature swings. The insulation material layer overlies the outer PCM layer, providing thermal insulation. The phase change point of the PCM outer layer is selected to ensure that the PCM outer layer stores latent heat before the onset of winter cold snaps. The phase change point of the PCM inner layer is selected to ensure that the PCM inner layer stores latent heat before the onset of winter; furthermore, the phase change point of the PCM outer layer is lower than that of the PCM inner layer. This invention can achieve permanent thermal insulation of the concrete structure surface, automatically adjust and control the concrete structure surface temperature, mitigate drastic temperature fluctuations, and prevent surface cracks caused by sudden temperature drops.

Description

Technical Field

[0001] The invention relates to a phase-change thermal insulation structure used for permanent thermal insulation of concrete structures. Background Art

[0002] Large temperature differences between the inside and outside of concrete structures are one of the main causes of concrete cracking. Therefore, thermal insulation measures must be implemented on the surface of concrete structures, both during construction and operation, to prevent drastic temperature fluctuations on the surface of the concrete structure, which can increase the temperature difference between the inside and outside of the concrete structure and lead to temperature cracks on the surface of the concrete structure. Winters in high-altitude regions are particularly cold and long, with large temperature differences between day and night and frequent cold waves, making temperature control and crack prevention in concrete structures more difficult. Summary of the Invention

[0003] In order to solve the influence of "cold" on the temperature stress of concrete structure and prevent cracks from occurring on the surface of concrete structure, the purpose of the present invention is to provide a phase change insulation structure for permanent insulation of concrete structure.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a phase change insulation structure for permanent thermal insulation of concrete structures, which comprises a PCM inner layer, a PCM outer layer and a thermal insulation material layer, wherein the PCM inner layer covers the concrete structure, the PCM outer layer covers the PCM inner layer, and the thermal insulation material layer covers the PCM outer layer;

[0005] The PCM outer layer is used to protect against winter cold waves and large temperature differences between day and night; the PCM inner layer is used to protect against sudden temperature drops during seasonal changes; the phase transition point of the PCM outer layer should be lower than the average winter temperature, and the selection of the phase transition point of the PCM outer layer should ensure that the PCM outer layer stores latent heat before the winter cold wave arrives; the phase transition point of the PCM inner layer should be lower than the average temperature before winter arrives, and the selection of the phase transition point of the PCM inner layer should ensure that the PCM inner layer stores latent heat before winter arrives; and the phase transition point of the PCM outer layer should be lower than the phase transition point of the PCM inner layer.

[0006] The PCM outer layer thickness δ c外 for:

[0007]

[0008] Where λ c外 is the thermal conductivity of the PCM outer layer; T c外 is the phase transition point of the PCM outer layer; T a is the temperature at any time during the winter cold wave; q 外潜is the latent heat per unit volume of the PCM outer layer; δ0 is the thickness of the insulation material layer; λ0 is the thermal conductivity of the insulation material; t0 represents the start time when the temperature drops below the phase transition point of the PCM outer layer during a winter cold wave; t1 represents the end time when the temperature drops below the phase transition point of the PCM outer layer during a winter cold wave;

[0009] The PCM inner layer thickness δ c内 :

[0010]

[0011] Where: c内 is the thermal conductivity of the PCM inner layer; T c外 is the phase transition point of the PCM outer layer; T h The temperature at any moment when the temperature drops sharply during season change; q 内潜 is the latent heat per unit volume of the PCM inner layer; δ0 is the thickness of the insulation material layer; λ0 is the thermal conductivity of the insulation material; δ c外 is the thickness of the PCM outer layer; c外 is the thermal conductivity of the PCM outer layer; T c内 is the phase transition point of the PCM inner layer; t2 is the starting time when the temperature is lower than the phase transition point of the PCM inner layer during the season change period; t3 is the ending time when the temperature is lower than the phase transition point of the PCM inner layer during the season change period;

[0012] The function of the thermal insulation material layer is to keep warm and insulate, and the thickness thereof is 5cm to 10cm.

[0013] Preferably, the PCM outer layer phase transition point T c外 for:

[0014] T c外 =T0-ΔT0

[0015] Where T0 is the average winter temperature; ΔT0 is the environmental compensation heat storage safety margin before the cold wave arrives, which is 2-3°C.

[0016] The PCM inner layer phase transition point T c内 for:

[0017] T c内 =T1-ΔT1

[0018] Where T1 is the average temperature before winter comes; ΔT1 is the environmental compensation heat storage safety margin before winter comes, which is 2-3℃.

[0019] Preferably, the PCM inner layer is composed of a low-temperature phase change material having a phase change point within the range of 5-15°C; and the PCM outer layer is composed of a low-temperature phase change material having a phase change point within the range of 5-15°C.

[0020] Preferably, the thermal insulation material layer is made of a material with low thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the phase change insulation structure for permanent thermal insulation of concrete structures according to the present invention. DETAILED DESCRIPTION

[0022] The structure and features of the present invention are described in detail below with reference to the accompanying drawings and embodiments. It should be noted that various modifications can be made to the embodiments disclosed herein. Therefore, the embodiments disclosed in the specification should not be regarded as limiting the present invention, but are merely examples of embodiments, the purpose of which is to make the features of the present invention apparent.

[0023] like Figure 1 As shown, the phase change insulation structure for permanent insulation of concrete structure disclosed in the present invention consists of a PCM inner layer 1, a PCM outer layer 2 and an insulation material layer 3. The PCM inner layer 1 is closely attached to the concrete structure 4 and covers the surface thereof, the PCM outer layer 2 covers the PCM inner layer 1, and the insulation material layer 3 covers the PCM outer layer 2.

[0024] The main function of the inner and outer PCM layers is to adaptively regulate temperature. During phase changes, i.e., when the PCM stores or releases heat, its own temperature remains unchanged. By releasing latent heat, the inner and outer PCM layers mitigate sudden drops in temperature, slowing the rapid decrease in the concrete structure's surface temperature. Specifically, the outer PCM layer protects against winter cold snaps and large diurnal temperature swings, while the inner PCM layer protects against sudden drops in temperature during seasonal changes.

[0025] When selecting materials for the inner and outer PCM layers, the phase transition point of the outer PCM layer should be chosen to ensure that it can store latent heat before the onset of a winter cold snap. The phase transition point should be lower than the average winter temperature. The phase transition point of the inner PCM layer should also be chosen to ensure that it can store latent heat before the onset of winter. The phase transition point should be lower than the average winter temperature. Furthermore, the phase transition point of the outer PCM layer should be lower than that of the inner PCM layer. This allows the phase transition of the outer PCM layer to slow the rapid drop in the inner PCM layer's temperature, thereby maintaining a higher temperature on the concrete structure surface.

[0026] PCM outer layer phase transition point T c外 Should be:

[0027] T c外 =T0-ΔT0

[0028] Where T0 is the average temperature in winter; ΔT0 is the environmental compensation heat storage safety margin before the cold wave arrives, which is usually 2-3°C. c内 Should be:

[0029] T c内 =T1-ΔT1

[0030] Where T1 is the average temperature before winter comes; ΔT1 is the environmental compensation heat storage safety margin before winter comes, which is usually 2-3℃.

[0031] The thickness of the PCM inner and outer layers determines the heat storage and release capacity of the PCM layer. The thickness of the PCM inner and outer layers should be determined based on the amount of heat that the PCM layer needs to release during the period of resisting a sudden drop in temperature. The PCM layer must have sufficient latent heat capacity to store heat.

[0032] PCM outer layer thickness δ c外 for:

[0033]

[0034] Where λ c外 is the thermal conductivity of the PCM outer layer; T c外 is the phase transition point of the PCM outer layer; T a is the temperature at any time during the winter cold wave; q 外潜 is the latent heat per unit volume of the PCM outer layer. When the material of the PCM outer layer is determined, q 外潜 is an inherent indicator; δ0 is the thickness of the insulation material layer; λ0 is the thermal conductivity of the insulation material; t0 represents the starting time when the temperature is lower than the phase transition point of the PCM outer layer during the winter cold wave; t1 represents the ending time when the temperature is lower than the phase transition point of the PCM outer layer during the winter cold wave.

[0035] PCM inner layer thickness δ c内 :

[0036]

[0037] Where: c内 is the thermal conductivity of the PCM inner layer; T 内 is the phase transition point of the PCM inner layer; T h The temperature at any moment when the temperature drops sharply during season change; q 内潜 is the latent heat per unit volume of the PCM inner layer. When the PCM inner layer material is determined, the q 内潜 is the inherent index; δ0 is the thickness of the insulation material layer; λ0 is the thermal conductivity of the insulation material; δ c外 is the thickness of the PCM outer layer; c外 is the thermal conductivity of the PCM outer layer; T c内 is the phase transition point of the inner layer of the PCM; t2 is the starting time when the temperature is lower than the phase transition point of the inner layer of the PCM during the season change; t3 is the ending time when the temperature is lower than the phase transition point of the inner layer of the PCM during the season change.

[0038] In a preferred embodiment of the present invention, the PCM inner layer is composed of a low-temperature phase-change material, such as paraffin wax or hydrated salts, with a phase transition point within the range of 5-15°C. The phase transition point is selected to ensure that the PCM inner layer stores latent heat before the onset of winter. The PCM outer layer is composed of a low-temperature phase-change material, such as paraffin wax or hydrated salts, with a phase transition point within the range of 5-15°C. The phase transition point is selected to ensure that the PCM outer layer stores latent heat before the onset of a winter cold snap. Furthermore, the phase transition point of the PCM outer layer is lower than that of the PCM inner layer. This allows the phase transition of the PCM outer layer to slow the rapid temperature drop of the PCM inner layer, thereby maintaining a higher temperature on the concrete structure surface.

[0039] The insulation material layer is located on the outer PCM layer. Its function is to keep the heat insulated, reduce heat flux, reduce the internal heat loss rate, and reduce the temperature drop of the concrete surface. On the one hand, it insulates the concrete structure; on the other hand, it insulates the inner and outer PCM layers, reducing the amount of PCM used.

[0040] In a preferred embodiment of the present invention, the thermal insulation material layer can be made of materials with low thermal conductivity, such as rubber-plastic sponge and thermal insulation cotton. When rubber-plastic sponge is selected, the thickness can be 5 cm, and when thermal insulation cotton is selected, the thickness can be 10 cm.

[0041] The present invention can achieve permanent heat preservation of the concrete surface, realize automatic regulation and control of the concrete surface temperature, slow down the violent fluctuation of the concrete surface temperature, and prevent the generation of surface cracks caused by a sudden drop in the concrete surface temperature.

[0042] Finally, it should be noted that the embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phase change insulation structure for permanent thermal insulation of concrete structures, characterized by: It consists of a PCM inner layer, a PCM outer layer and a thermal insulation material layer. The PCM inner layer is covered on the concrete structure, the PCM outer layer is covered on the PCM inner layer, and the thermal insulation material layer is covered on the PCM outer layer. The PCM outer layer is used to protect against winter cold waves and large temperature differences between day and night; the PCM inner layer is used to protect against sudden temperature drops during seasonal changes; the phase transition point of the PCM outer layer should be lower than the average winter temperature, and the selection of the phase transition point of the PCM outer layer should ensure that the PCM outer layer stores latent heat before the winter cold wave arrives; the phase transition point of the PCM inner layer should be lower than the average temperature before winter arrives, and the selection of the phase transition point of the PCM inner layer should ensure that the PCM inner layer stores latent heat before winter arrives; and the phase transition point of the PCM outer layer should be lower than the phase transition point of the PCM inner layer. The PCM outer layer thickness δ c外 for: Where λ c外 is the thermal conductivity of the PCM outer layer; T c外 is the phase transition point of the PCM outer layer; T a is the temperature at any time during the winter cold wave; q 外潜 is the latent heat per unit volume of the PCM outer layer; δ0 is the thickness of the insulation material layer; λ0 is the thermal conductivity of the insulation material; t0 represents the starting time when the temperature during the winter cold wave is lower than the phase transition point of the PCM outer layer; t1 represents the end time when the temperature during the winter cold wave is below the phase transition point of the PCM outer layer; The PCM inner layer thickness δ c内 : Where: c内 is the thermal conductivity of the PCM inner layer; T c外 is the phase transition point of the PCM outer layer; T h The temperature at any moment when the temperature drops sharply during season change; q 内潜 is the latent heat per unit volume of the PCM inner layer; δ0 is the thickness of the insulation material layer; λ0 is the thermal conductivity of the insulation material; δ c外 is the thickness of the PCM outer layer; c外 is the thermal conductivity of the PCM outer layer; T c内 is the phase transition point of the PCM inner layer; t2 is the starting time when the temperature is lower than the phase transition point of the PCM inner layer during the season change period; t3 is the ending time when the temperature is lower than the phase transition point of the PCM inner layer during the season change period; The function of the thermal insulation material layer is to keep warm and insulate, and the thickness thereof is 5cm to 10cm.

2. The phase change thermal insulation structure for permanent thermal insulation of concrete structure according to claim 1, characterized in that: The PCM outer layer phase transition point T c外 for: T c外 =T0-ΔT0 Where T0 is the average winter temperature; ΔT0 is the environmental compensation heat storage safety margin before the cold wave arrives, which is 2-3°C. The PCM inner layer phase transition point T c内 for: T c内 =T1-ΔT1 Where T1 is the average temperature before winter comes; ΔT1 is the environmental compensation heat storage safety margin before winter comes, which is 2-3℃.

3. The phase change thermal insulation structure for permanent thermal insulation of concrete structure according to claim 2, characterized in that: The PCM inner layer is composed of a low-temperature phase change material with a phase change point in the range of 5-15°C; The PCM outer layer is made of a low-temperature phase change material with a phase change point in the range of 5-15°C.

4. The phase change thermal insulation structure for permanent thermal insulation of concrete structure according to any one of claims 1 to 3, characterized in that: The heat-insulating material layer is made of a material with low thermal conductivity.

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