Phase change thermal insulation structure for temporary thermal insulation during the construction period of concrete structures

Abstract

The present invention provides a phase change thermal insulation structure for temporary thermal insulation during the construction period of a concrete structure. On the basis of covering the surface of the concrete structure with a traditional thermal insulation material layer, a PCM inner layer and a PCM outer layer are additionally provided. The PCM inner layer covers the thermal insulation material layer, and the PCM outer layer covers the PCM inner layer. The PCM inner layer is used to resist the diurnal temperature difference, and the selection of the phase change point of the PCM inner layer should ensure that its temperature can be maintained stable through the compensation of the diurnal temperature difference; the PCM outer layer is used to resist cold snaps, and the selection of the phase change point of the PCM outer layer should ensure that it can store latent heat through the compensation of the ambient temperature before the cold snap comes; the phase change point of the PCM inner layer should be higher than that of the PCM outer layer. The present invention can realize the temporary thermal insulation of the surface of the concrete structure during the construction period, realize the automatic regulation and control of the surface temperature of the concrete structure, slow down the drastic fluctuation of the surface temperature of the concrete structure, and prevent the generation of surface cracks on the surface of the concrete structure caused by sudden temperature drop.

Description

Technical Field

[0001] The present invention relates to a phase change thermal insulation structure for temporary thermal insulation during the construction period of concrete structures. Background Art

[0002] During the construction period of concrete structures, affected by adverse climatic conditions such as cold snaps and large day-night temperature differences, if thermal insulation measures are not taken, the surface temperature of the concrete structure will drop sharply, resulting in a large internal-external temperature difference and causing cracks on the surface of the concrete structure. Therefore, it is particularly important to take thermal insulation measures during the construction period of concrete structures to prevent the internal-external temperature difference of the concrete structure from increasing due to the drastic change in the surface temperature of the concrete structure, resulting in temperature cracks on the surface of the concrete structure. Summary of the Invention

[0003] In order to prevent the surface temperature of the concrete structure from dropping sharply and the internal-external temperature difference from increasing during the construction period, thereby causing cracks on its surface, the purpose of the present invention is to provide a phase change thermal insulation structure for temporary thermal insulation during the construction period of concrete structures.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A phase change thermal insulation structure for temporary thermal insulation during the construction period of concrete structures, characterized in that: on the basis of covering the surface of the concrete structure with a traditional thermal insulation material layer, a PCM inner layer and a PCM outer layer are additionally provided, the PCM inner layer covers the thermal insulation material layer, and the PCM outer layer covers the PCM inner layer;

[0005] The PCM inner layer is used to resist the day-night temperature difference, and the selection of the phase change point of the PCM inner layer should ensure that its temperature can be maintained stable through the compensation of the day-night temperature difference; the PCM outer layer is used to resist cold snaps, and the selection of the phase change point of the PCM outer layer should ensure that it can store latent heat through the compensation of the ambient temperature before the cold snap arrives; the phase change point of the PCM inner layer is higher than that of the PCM outer layer;

[0006] The thickness δ of the PCM outer layer c外 is:

[0007]

[0008] where λ c外 is the thermal conductivity of the PCM outer layer; T c外 is the phase change point of the PCM outer layer; T a is the air temperature at any moment during the cold snap; q 外潜 is the latent heat per unit volume of the PCM outer layer; t1 represents the starting moment when the air temperature is lower than the phase change point of the PCM outer layer during the cold snap; t2 represents the ending moment when the air temperature is lower than the phase change point of the PCM outer layer during the cold snap;

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

[0010]

[0011] Wherein, λ c内 is the thermal conductivity of the inner layer of the PCM; T c内 is the phase change point of the inner layer of the PCM; T1 is the air temperature at any moment during the large day-night temperature difference period; q 内潜 is the latent heat per unit volume of the inner layer of the PCM; δ c外 is the thickness of the outer layer of the PCM; λ c外 is the thermal conductivity of the outer layer of the PCM; t3 represents the starting moment when the air temperature is lower than the phase change point of the inner layer of the PCM during the large day-night temperature difference period; t4 represents the ending moment when the air temperature is lower than the phase change point of the inner layer of the PCM during the large day-night temperature difference period.

[0012] Preferably, the phase change point T of the inner layer of the PCM c内 is:

[0013] T c内 = T0

[0014] Wherein, T0 is the daily average air temperature for withstanding the day-night temperature difference;

[0015] The phase change point T of the outer layer of the PCM c外 is:

[0016] T c外 = T d - ΔT

[0017] Wherein, T d is the average air temperature in the week before the cold snap; ΔT is the environmental compensation heat storage safety margin before the cold snap, and the value range is 2 - 3°C.

[0018] Preferably, the inner layer of the PCM is composed of a low-temperature phase change material with a phase change point in the range of 5 - 15°C; the outer layer of the PCM is composed of a low-temperature phase change material with a phase change point in the range of 5 - 15°C.

[0019] Preferably, the thermal insulation material layer is made of a material with low thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the phase change thermal insulation structure for temporary thermal insulation during the construction period of the concrete structure of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] The structure and features of the present invention will be described in detail below with reference to the 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 a limitation of the present invention, but only as examples of the embodiments, and the purpose is to make the features of the present invention obvious.

[0022] As Figure 1 shown, the phase change thermal insulation structure for temporary thermal insulation during the construction period of the concrete structure disclosed by the present invention is composed of a thermal insulation material layer 1, a PCM inner layer 2, and a PCM outer layer 3. The thermal insulation material layer 1 is closely attached to the surface of the just-poured concrete structure 4. The PCM inner layer 2 covers the thermal insulation material layer 1, and the PCM outer layer 3 covers the PCM inner layer 2.

[0023] Based on covering the surface of the concrete structure 4 with the traditional thermal insulation material layer 1, the present invention sets a PCM inner layer and a PCM outer layer to conduct temporary thermal insulation on the concrete structure during the construction period. The main function of the present invention is to resist cold snaps and sudden drops in temperature caused by large day-night temperature differences, automatically adjust and control the surface temperature of the concrete, slow down the sharp decrease in the surface temperature of the concrete structure, thermally insulate the surface of the concrete structure, and prevent cracks from occurring on the surface of the concrete structure.

[0024] The thermal insulation material layer 1 covers the surface of the concrete structure 4, and its function is to provide thermal insulation, reduce the heat flux, reduce the heat dissipation rate inside the concrete structure, and reduce the temperature drop on the surface of the concrete structure.

[0025] 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 and plastic sponge, thermal insulation cotton, etc., and its thickness is 5 cm to 10 cm.

[0026] The main functions of the PCM inner layer and the outer layer are to conduct adaptive temperature regulation. When the PCM undergoes a phase change, that is, when it stores (releases) heat, its own temperature does not change. The PCM inner layer and the outer layer resist sudden drops in temperature by releasing latent heat and slow down the rapid decrease in the surface temperature of the concrete structure. Specifically, the PCM outer layer is used to resist cold snaps; the PCM inner layer is used to resist day-night temperature differences.

[0027] When selecting the materials for the inner and outer layers of the PCM, the phase change point of the inner layer 2 of the PCM should be higher than that of the outer layer 3 of the PCM. For the inner layer of the PCM, when the daily air temperature is higher than the phase change point of the inner layer of the PCM, the inner layer of the PCM stores heat and its own temperature remains unchanged. When the daily air temperature is lower than the phase change point of the inner layer of the PCM, the inner layer of the PCM releases heat and its own temperature remains unchanged. The heat storage and release balance of the PCM layer is compensated by the daily temperature difference, so that the temperature of the inner layer of the PCM is maintained at the phase change point. For the outer layer of the PCM, when a cold snap occurs and the temperature drops suddenly, and the temperature is lower than the phase change point of the outer layer of the PCM, the outer layer of the PCM releases heat and its own temperature remains unchanged until the cold snap ends, and the temperature of the outer layer of the PCM is maintained at its phase change point; after the cold snap, when the temperature rises, when the temperature is higher than the phase change point of the outer layer of the PCM, the outer layer of the PCM stores heat by environmental temperature compensation to resist the next cold snap. In short, the reason why the phase change point of the outer layer of the PCM for resisting cold snaps is lower is to ensure that it can store heat by environmental compensation after the cold snap to resist the next cold snap; the reason why the phase change point of the inner layer of the PCM for resisting the daily temperature difference is higher is that it can keep the inner layer of the PCM at a higher temperature to increase the heat preservation effect.

[0028] The PCM phase change point refers to the temperature at which the PCM undergoes a phase change. The PCM phase change point should be determined according to the ambient temperature conditions of the specific application. The temporary heat preservation during the construction period of the concrete structure mainly resists cold snaps and large daily temperature differences. When resisting cold snaps, the selection of the phase change point of the outer layer of the PCM should ensure that the outer layer of the PCM can store latent heat by environmental compensation before the cold snap arrives, and its phase change point should be lower than the phase change point compensated and balanced by the environment before the temporary heat preservation against cold snaps; when selecting the phase change point of the inner layer of the PCM for resisting large daily temperature differences, it should be ensured as much as possible that it can achieve temperature difference compensation and maintain a stable temperature, and its phase change point should be selected as the phase change point compensated and balanced by the daily temperature difference during the temporary heat preservation against the daily temperature difference.

[0029] The phase change point T of the inner layer of the PCM c内 is:

[0030] T c内 = T0

[0031] In the formula, T0 is the average daily air temperature when resisting the daily temperature difference.

[0032] The phase change point T of the outer layer of the PCM c外 is:

[0033] T c外 = T d - ΔT

[0034] In the formula, T d is the average weekly air temperature before the cold snap arrives; ΔT is the safety margin for environmental compensation and heat storage before the cold snap arrives, and the general value range is 2 - 3 °C.

[0035] The thickness of the inner and outer layers of the PCM determines the heat storage and release capacity of the PCM layer. The thickness of the PCM layer should be determined according to the heat to be released by the PCM layer during cold snaps or large day-night temperature differences. The PCM layer should have sufficient latent heat capacity to store and release heat while maintaining its own temperature constant.

[0036] The thickness δ of the outer layer of the PCM c外 is:

[0037]

[0038] In the formula, λ c外 is the thermal conductivity of the outer layer of the PCM; T c外 is the phase change point of the outer layer of the PCM; T a is the air temperature at any time during the cold snap; q 外潜 is the latent heat per unit volume of the outer layer of the PCM, q 外潜 is an inherent index of the PCM (phase change material). When the PCM is determined, its q 外潜 is determined; t1 represents the starting time when the air temperature is lower than the phase change point of the outer layer of the PCM during the cold snap; t2 represents the ending time when the air temperature is lower than the phase change point of the outer layer of the PCM during the cold snap.

[0039] The thickness δ of the inner layer of the PCM c内 is:

[0040]

[0041] In the formula, λ c内 is the thermal conductivity of the inner layer of the PCM; T c内 is the phase change point of the inner layer of the PCM; T1 is the air temperature at any time during the large day-night temperature difference; q 内潜 is the latent heat per unit volume of the inner layer of the PCM, q 内潜 is an inherent index of the PCM (phase change material). After the PCM is determined, its q 内潜 is determined; δ c外 is the thickness of the outer layer of the PCM; λ c外 is the thermal conductivity of the outer layer of the PCM; t3 represents the starting time when the air temperature is lower than the phase change point of the inner layer of the PCM during the large day-night temperature difference; t4 represents the ending time when the air temperature is lower than the phase change point of the inner layer of the PCM during the large day-night temperature difference.

[0042] In a preferred embodiment of the present invention, the inner layer of the PCM is composed of low-temperature phase change materials with a phase change point in the range of 5-15°C, such as paraffin, hydrated salts, etc. The selection of its phase change point should ensure that it can maintain its temperature stability through the compensation of day-night temperature difference; the outer layer of the PCM is composed of low-temperature phase change materials with a phase change point in the range of 5-15°C, such as paraffin, hydrated salts, etc. The selection of its phase change point should ensure that the outer layer of the PCM can store latent heat through the compensation of ambient temperature before the cold snap arrives; moreover, the phase change point of the inner layer of the PCM should be higher than that of the outer layer of the PCM.

[0043] The present invention can achieve the temporary insulation of the surface of the concrete structure during the construction period, automatically adjust and control the surface temperature of the concrete, slow down the drastic fluctuation of the surface temperature of the concrete, and prevent the generation of surface cracks caused by the sudden drop of the surface temperature of the concrete.

[0044] Finally, it should be noted that the above-mentioned embodiments 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phase change thermal insulation structure for temporary thermal insulation during the construction period of a concrete structure, characterized in that: On the basis of covering the surface of the concrete structure with a traditional thermal insulation material layer, a PCM inner layer and a PCM outer layer are additionally provided. The PCM inner layer covers the thermal insulation material layer, and the PCM outer layer covers the PCM inner layer; The PCM inner layer is used to resist the diurnal temperature difference. The selection of the phase change point of the PCM inner layer should ensure that its temperature can be maintained stable through the compensation of the diurnal temperature difference; the PCM outer layer is used to resist cold snaps. The selection of the phase change point of the PCM outer layer should ensure that it can store latent heat through the compensation of the ambient temperature before the cold snap comes; the phase change point of the PCM inner layer should be higher than that of the PCM outer layer; The thickness δ of the outer layer of the PCM c外 is as follows: where λ c外 is the thermal conductivity of the outer layer of the PCM; T c外 is the phase change point of the outer layer of the PCM; T a is the air temperature at any time during the cold snap; q 外潜 is the latent heat per unit volume of the outer layer of the PCM; t1 represents the starting time when the air temperature is lower than the phase change point of the outer layer of the PCM during the cold snap; t2 represents the ending time when the air temperature is lower than the phase change point of the outer layer of the PCM during the cold snap; The thickness δ of the inner layer of the PCM c内 : where λ c内 is the thermal conductivity of the inner layer of the PCM; T c内 is the phase change point of the inner layer of the PCM; T1 is the air temperature at any moment during the large day-night temperature difference period; q 内潜 is the latent heat per unit volume of the inner layer of the PCM; δ c外 is the thickness of the outer layer of the PCM; λ c外 is the thermal conductivity of the outer layer of the PCM; t3 represents the starting moment when the air temperature is lower than the phase change point of the inner layer of the PCM during the large day-night temperature difference period; t4 represents the ending moment when the air temperature is lower than the phase change point of the inner layer of the PCM during the large day-night temperature difference period.

2. The phase change thermal insulation structure for temporary thermal insulation during the construction period of a concrete structure according to claim 1, wherein: The phase change point T of the inner layer of the PCM c内 is as follows: T c内 = T0 In the formula, T0 is the daily average air temperature when resisting the diurnal temperature difference; The phase change point T of the outer layer of the PCM c外 is as follows: T c外 = T d - ΔT where, T d is the average temperature in the week before the cold snap; ΔT is the environmental compensation heat storage safety margin before the cold snap, and the value range is 2-3°C.

3. The phase change thermal insulation structure for temporary thermal insulation during the construction period of a concrete structure according to claim 1 or 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 composed of a low-temperature phase change material with a phase change point in the range of 5-15°C.

4. The phase change heat preservation structure for temporary heat preservation during the construction period of a concrete structure according to claim 3, characterized in that: The thermal insulation material layer is made of a material with a low thermal conductivity.

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