Frozen soil heat pipe structure with vacuum enhanced radiation refrigeration coupling phase change module

Abstract

The utility model relates to a frozen soil heat pipe structure with a vacuum enhanced radiation refrigeration coupling phase change module, and belongs to the technical field of frozen soil roadbed heat pipes. In order to solve the problem that the existing frozen soil roadbed heat pipe does not work in summer, the utility model provides a frozen soil heat pipe structure with a vacuum enhanced radiation refrigeration coupling phase change module, which comprises a heat pipe and the vacuum enhanced radiation refrigeration coupling phase change module, the vacuum enhanced radiation refrigeration coupling phase change module comprises a cold storage and heat exchange device, a daytime radiation refrigeration layer laid on the upper surface of the cold storage and heat exchange device, and a heat preservation layer arranged on the periphery of the cold storage and heat exchange device. The vacuum cavity is arranged on the periphery of the heat preservation layer, the optical window is arranged on the upper surface of the daytime radiation refrigeration layer, the vacuum cavity and the optical window are combined in a sealed mode to form a vacuum environment, convection and heat conduction are isolated, and therefore stronger refrigeration and cold storage effects are generated; the heat pipe is more efficiently driven to work all year round to maintain the thermal stability of the frozen soil foundation.

Description

Technical Field

[0001] This utility model belongs to the field of heat pipe technology for frozen soil roadbeds, and particularly relates to a frozen soil heat pipe structure with a vacuum-enhanced radiation cooling coupling phase change module. Background Technology

[0002] After asphalt blackening is applied to roads in permafrost regions, the absorption rate of solar radiation increases by 20%. Furthermore, the presence of the road surface inhibits the evaporation of water and heat from the roadbed. The latent heat of evaporation cannot be dissipated through the asphalt surface, and the resulting permafrost thawing activity threatens the safety of infrastructure, leading to increased maintenance costs, shortened service life, and real economic damage.

[0003] To mitigate permafrost degradation and improve the thermal stability of permafrost roadbeds, numerous measures have been implemented, such as laying gravel layers to increase roadbed height, using ventilation pipes, and installing sunshades to enhance heat dissipation, while preventing convective heat transfer caused by windblown sand or snow accumulation. Currently, heat pipes are used, generating significant cooling capacity to cool the roadbed during the cold season. However, heat pipes only transfer heat in one direction. During the warmer seasons when cooling is most needed, the heat pipes cannot activate when the ground temperature is lower than the air temperature, thus failing to cool the roadbed. Therefore, developing highly reliable, year-round operating heat pipes for permafrost roadbeds is a pressing issue that needs to be addressed in this field. Summary of the Invention

[0004] To address the problem of existing heat pipes in permafrost subgrades not working in summer, this invention provides a permafrost heat pipe structure with a vacuum-enhanced radiation cooling coupling phase change module.

[0005] The technical solution of this utility model:

[0006] A permafrost heat pipe structure with a vacuum-enhanced radiative cooling coupled phase change module includes a heat pipe and a vacuum-enhanced radiative cooling coupled phase change module disposed on the top of the heat pipe. The vacuum-enhanced radiative cooling coupled phase change module includes a cold storage heat exchange device, a daytime radiative cooling layer laid on the upper surface of the cold storage heat exchange device, an insulation layer disposed on the side walls and bottom periphery of the cold storage heat exchange device, a vacuum shell disposed on the periphery of the insulation layer, and an optical window disposed on the upper surface of the daytime radiative cooling layer. The vacuum shell and the optical window are sealed together to form a vacuum environment. The top of the heat pipe extends into the interior of the cold storage heat exchange device and contacts the phase change cold storage material stored in the cold storage heat exchange device.

[0007] Furthermore, a heat exchange fin assembly is provided on the outer periphery of the top of the heat pipe. The heat exchange fin assembly extends into the interior of the cold storage heat exchange device and comes into contact with the phase change cold storage material stored in the cold storage heat exchange device.

[0008] Furthermore, a heat exchange fin assembly is provided on the outer periphery of the top of the heat pipe. The upper half of the heat exchange fin assembly extends into the interior of the cold storage and heat exchange device and contacts the phase change cold storage material stored in the cold storage and heat exchange device. The lower half of the heat exchange fin assembly is on the outside of the cold storage and heat exchange device and contacts the atmospheric environment.

[0009] Furthermore, the daytime radiation cooling layer is a daytime radiation cooling coating, a daytime radiation cooling film, a daytime radiation cooling paint, or a daytime radiation cooling fabric.

[0010] Furthermore, the phase change cold storage material stored in the cold storage and heat exchange device is composed of a polymer gel matrix, a phase change material, and water. The polymer gel matrix is ​​one or a combination of hydroxypropyl methylcellulose, methylcellulose, or carboxymethylcellulose. The phase change material is one or a combination of barium chloride-water system, glycine-glycerol complex, n-tetane, or water-mixed potassium sorbate.

[0011] Furthermore, the insulation layer is made of phenolic foam material, expanded vitrified microspheres, rubber and plastic insulation material, or glass wool.

[0012] Furthermore, the optical window is a highly transparent optical window, made of highly transparent glass or ZnS.

[0013] Furthermore, the heat pipe contains, from bottom to top, a liquid cooling section, an evaporation section, a transition section, and a heat dissipation section.

[0014] Furthermore, the liquid refrigeration section is used to store liquid refrigerant and circulate heat in the heat pipe. After absorbing heat from the frozen soil, the liquid refrigerant absorbs heat, vaporizes, and rises from the evaporation section, carrying away heat. Upon reaching the transition section, it transforms from liquid refrigerant into gaseous refrigerant. The gaseous refrigerant exchanges heat with the phase change cold storage material in the cold storage and heat exchange device in the heat dissipation section, or exchanges heat with the phase change cold storage material in the cold storage and heat exchange device or the atmospheric environment through the heat exchange fin assembly, and then recondenses from the gaseous state into the liquid state.

[0015] The beneficial effects of this utility model are:

[0016] Daytime radiative cooling technology utilizes strong reflection of the solar spectrum (0.3-2.5μm) and through an "atmospheric window" (8-13μm) to cool the environment in a vacuum (3K outer space) without consuming any energy. Under vacuum conditions, it can achieve temperatures 40°C lower than ambient temperatures, even reaching -20°C in high-altitude areas during summer. Phase change material (PCM) cooling technology leverages the characteristic of PCM materials to maintain a near-constant temperature by absorbing or releasing large amounts of energy during phase change, thus controlling the surrounding environment temperature. This solves the problem of energy supply and demand mismatch in time and space and improves energy efficiency. This invention couples daytime radiative cooling technology with PCM cooling, using daytime radiative cooling material to cool and store PCM materials, then exchanging heat with a heat pipe. Simultaneously, a vacuum environment is created to isolate convection and conduction, resulting in stronger cooling and cooling effects. This more efficiently drives the heat pipe to operate year-round, maintaining the thermal stability of permafrost foundations and solving the problem that existing heat pipes cannot operate during the warmest season when cooling is most needed, due to ambient temperatures exceeding permafrost temperatures. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the permafrost heat pipe structure with vacuum-enhanced radiation cooling coupling phase change module described in Example 1.

[0018] Figure 2 This is a schematic diagram of the permafrost heat pipe structure with vacuum-enhanced radiation cooling coupling phase change module described in Example 2.

[0019] Figure 3 This is a schematic diagram of the permafrost heat pipe structure with vacuum-enhanced radiation cooling coupling phase change module described in Example 3.

[0020] In the figure, 1 is a heat pipe; 101 is a heat exchange fin assembly; 2 is a vacuum-enhanced radiation cooling coupled phase change module; 201 is a cold storage heat exchange device; 202 is a daytime radiation cooling layer; 203 is an insulation layer; 204 is a vacuum shell; and 205 is an optical window. Detailed Implementation

[0021] The technical solution of this utility model will be further described below with reference to embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of this utility model that do not depart from the spirit and scope of this utility model should be covered within the protection scope of this utility model. In the following embodiments, the process equipment or devices not specifically specified are all conventional equipment or devices in the art. Unless otherwise specified, the raw materials used in the embodiments of this utility model are all commercially available. Unless otherwise specified, the technical means used in the embodiments of this utility model are all conventional means well known to those skilled in the art.

[0022] Example 1

[0023] This invention provides a permafrost heat pipe structure with a vacuum-enhanced radiation cooling coupled phase change module, which consists of a heat pipe 1 and a vacuum-enhanced radiation cooling coupled phase change module 2 fixedly installed on the top of the heat pipe.

[0024] The vacuum-enhanced radiative cooling coupled phase change module 2 includes a cold storage heat exchange device 201, a daytime radiative cooling layer 202 laid on the upper surface of the cold storage heat exchange device 201, an insulation layer 203 disposed on the side walls and bottom periphery of the cold storage heat exchange device 201, a vacuum shell layer 204 disposed around the insulation layer 203, and an optical window 205 disposed on the upper surface of the daytime radiative cooling layer 202. The vacuum shell layer 204 and the optical window 205 are sealed together to form a vacuum environment, isolating convection and heat conduction, thereby generating a stronger cooling and cold storage effect. The cold storage heat exchange device 201 is fixedly disposed on the top of the heat pipe 1, and the top of the heat pipe 1 extends into the interior of the cold storage heat exchange device 201, contacting the phase change material stored in the cold storage heat exchange device 201.

[0025] In this embodiment, the daytime radiation cooling layer is a daytime radiation cooling coating, composed of functional fillers and a matrix. The specific preparation method is as follows, and the amount of each raw material added is in parts by mass:

[0026] Step 1: Mix 30 parts of TiO2 particles with a particle size distribution of 0.2-1μm, 10 parts of SiO2 particles with a particle size distribution of 2-10μm, 10 parts of deionized water as solvent, 2 parts of sodium polycarboxylate as dispersant, 2 parts of acrylate homopolymer as leveling agent, and 1.5 parts of propylene glycol phenyl ether as film-forming aid. Stir the mixture in a mixer at 100r / min for 30min to prepare a color paste.

[0027] Step 2: Add 40 parts of water-based acrylic resin and 1 part of carboxymethyl cellulose thickener to the color paste prepared in Step 1, and stir in a mixer at 500 r / min for 30 min until uniform to obtain radiation cooling coating.

[0028] Step 3: Apply the coating obtained in Step 2 to the surface of the aluminum sheet using a flow coating method, and after drying, obtain a radiation cooling coating with a thickness of 200μm.

[0029] The phase change cold storage material stored in the cold storage and heat exchange device 201 of this embodiment is composed of a polymer gel matrix, a phase change material, and water. The specific preparation method is as follows, and the amount of each raw material added is in parts by mass:

[0030] Two parts of hydroxypropyl methylcellulose polymeric gel matrix, 20 parts of barium chloride-water phase change material, and 80 parts of water were stirred at 500 r / min for 30 min at room temperature and then loaded into a cold storage and heat exchange device 201 to obtain a phase change cold storage material with a thickness of 10 cm.

[0031] The daytime radiation cooling coating is placed on top of the cold storage heat exchange device 201 with an opening at the top, so that the phase change cold storage material inside the cold storage heat exchange device 201 can directly contact the aluminum plate at the bottom of the daytime radiation cooling coating, thereby achieving the cooling of the phase change cold storage material by the daytime radiation cooling coating.

[0032] The working principle and method of the frozen soil heat pipe structure in this embodiment are as follows:

[0033] According to the requirements, a permafrost roadbed heat pipe system with a radiation cooling coupling phase change module is inserted into the permafrost foundation. The heat pipe 1 contains a liquid cooling section, an evaporation section, a transition section and a heat dissipation section from bottom to top. When inserting the permafrost heat pipe structure into the permafrost foundation, the liquid cooling section and the evaporation section are inserted into the permafrost foundation.

[0034] The liquid cooling section of the heat pipe stores liquid refrigerant and circulates heat within the pipe. After absorbing heat from the frozen soil subgrade, the liquid refrigerant vaporizes in the evaporation section, rises, and carries away the heat. Upon reaching the transition section, it transforms from a liquid refrigerant into a gaseous refrigerant. In the heat dissipation section at the top of the heat pipe, the gaseous refrigerant exchanges heat with the phase change cold storage material in the cold storage heat exchange device, and condenses back into a liquid state.

[0035] Example 2

[0036] This invention provides a permafrost heat pipe structure with a vacuum-enhanced radiation cooling coupled phase change module, which consists of a heat pipe 1 and a vacuum-enhanced radiation cooling coupled phase change module 2 fixedly installed on the top of the heat pipe.

[0037] The vacuum-enhanced radiative cooling coupled phase change module 2 includes a cold storage heat exchange device 201, a daytime radiative cooling layer 202 laid on the upper surface of the cold storage heat exchange device 201, an insulation layer 203 disposed on the side walls and bottom periphery of the cold storage heat exchange device 201, a vacuum shell layer 204 disposed on the periphery of the insulation layer 203, and an optical window 205 disposed on the upper surface of the daytime radiative cooling layer 202. The vacuum shell layer 204 and the optical window 205 are sealed together to form a vacuum environment, isolating convection and heat conduction, thereby generating a stronger cooling and cold storage effect. The cold storage heat exchange device 201 is fixedly disposed on the top of the heat pipe 1. A heat exchange fin assembly 101 is also disposed on the outer periphery of the top of the heat pipe 1. The heat exchange fin assembly 101 extends into the interior of the cold storage heat exchange device 201 and contacts the phase change material stored in the cold storage heat exchange device 201.

[0038] In this embodiment, the daytime radiation cooling layer is a daytime radiation cooling coating, composed of functional fillers and a matrix. The specific preparation method is as follows, and the amount of each raw material added is in parts by mass:

[0039] Step 1: Mix 30 parts of TiO2 particles with a particle size distribution of 0.2-1μm, 10 parts of SiO2 particles with a particle size distribution of 2-10μm, 10 parts of deionized water as solvent, 2 parts of sodium polycarboxylate as dispersant, 2 parts of acrylate homopolymer as leveling agent, and 1.5 parts of propylene glycol phenyl ether as film-forming aid. Stir the mixture in a mixer at 100r / min for 30min to prepare a color paste.

[0040] Step 2: Add 40 parts of water-based acrylic resin and 1 part of carboxymethyl cellulose thickener to the color paste prepared in Step 1, and stir in a mixer at 500 r / min for 30 min until uniform to obtain radiation cooling coating.

[0041] Step 3: Apply the coating obtained in Step 2 to the surface of the aluminum sheet using a flow coating method, and after drying, obtain a radiation cooling coating with a thickness of 200μm.

[0042] The phase change cold storage material stored in the cold storage and heat exchange device 201 of this embodiment is composed of a polymer gel matrix, a phase change material, and water. The specific preparation method is as follows, and the amount of each raw material added is in parts by mass:

[0043] Two parts of hydroxypropyl methylcellulose polymeric gel matrix, 20 parts of barium chloride-water phase change material, and 80 parts of water were stirred at 500 r / min for 30 min at room temperature and then loaded into a cold storage and heat exchange device 201 to obtain a phase change cold storage material with a thickness of 10 cm.

[0044] The daytime radiation cooling coating is placed on top of the cold storage heat exchange device 201 with an opening at the top, so that the phase change cold storage material inside the cold storage heat exchange device 201 can directly contact the aluminum plate at the bottom of the daytime radiation cooling coating, thereby achieving the cooling of the phase change cold storage material by the daytime radiation cooling coating.

[0045] The working principle and method of the frozen soil heat pipe structure in this embodiment are as follows:

[0046] According to the requirements, a permafrost roadbed heat pipe system with a radiation cooling coupling phase change module is inserted into the permafrost foundation. The heat pipe 1 contains a liquid cooling section, an evaporation section, a transition section and a heat dissipation section from bottom to top. When inserting the permafrost heat pipe structure into the permafrost foundation, the liquid cooling section and the evaporation section are inserted into the permafrost foundation.

[0047] The liquid cooling section of the heat pipe stores liquid refrigerant and circulates heat within the pipe. After absorbing heat from the frozen soil subgrade, the liquid refrigerant vaporizes in the evaporation section, rises, and carries away the heat. Upon reaching the transition section, it transforms from a liquid to a gaseous refrigerant. In the heat dissipation section at the top of the heat pipe, the gaseous refrigerant achieves efficient heat exchange with the phase change storage material in the cold storage heat exchange device through heat exchange fins, and then recondenses from a gaseous state back into a liquid state.

[0048] Example 3

[0049] This invention provides a permafrost heat pipe structure with a vacuum-enhanced radiation cooling coupled phase change module, which consists of a heat pipe 1 and a vacuum-enhanced radiation cooling coupled phase change module 2 fixedly installed on the top of the heat pipe.

[0050] The vacuum-enhanced radiation cooling coupled phase change module 2 includes a cold storage heat exchange device 201, a daytime radiation cooling layer 202 laid on the upper surface of the cold storage heat exchange device 201, an insulation layer 203 disposed on the side wall and bottom periphery of the cold storage heat exchange device 201, a vacuum shell layer 204 disposed on the periphery of the insulation layer 203, and an optical window 205 disposed on the upper surface of the daytime radiation cooling layer 202. The vacuum shell layer 204 and the optical window 205 are sealed together to form a vacuum environment, which isolates convection and heat conduction, and can produce a stronger cooling and cold storage effect. The cold storage heat exchange device 201 is fixedly disposed on the top of the heat pipe 1. A heat exchange fin assembly 101 is also disposed on the outer periphery of the top of the heat pipe 1. The upper half of the heat exchange fin assembly 101 extends into the interior of the cold storage heat exchange device 201 and contacts the phase change material stored in the cold storage heat exchange device 201. The lower half of the heat exchange fin assembly 101 is on the outside of the cold storage heat exchange device 201 and contacts the atmosphere.

[0051] In this embodiment, the daytime radiation cooling layer is a daytime radiation cooling coating, composed of functional fillers and a matrix. The specific preparation method is as follows, and the amount of each raw material added is in parts by mass:

[0052] Step 1: Mix 30 parts of TiO2 particles with a particle size distribution of 0.2-1μm, 10 parts of SiO2 particles with a particle size distribution of 2-10μm, 10 parts of deionized water as solvent, 2 parts of sodium polycarboxylate as dispersant, 2 parts of acrylate homopolymer as leveling agent, and 1.5 parts of propylene glycol phenyl ether as film-forming aid. Stir the mixture in a mixer at 100r / min for 30min to prepare a color paste.

[0053] Step 2: Add 40 parts of water-based acrylic resin and 1 part of carboxymethyl cellulose thickener to the color paste prepared in Step 1, and stir in a mixer at 500 r / min for 30 min until uniform to obtain radiation cooling coating.

[0054] Step 3: Apply the coating obtained in Step 2 to the surface of the aluminum sheet using a flow coating method, and after drying, obtain a radiation cooling coating with a thickness of 200μm.

[0055] The phase change cold storage material stored in the cold storage and heat exchange device 201 of this embodiment is composed of a polymer gel matrix, a phase change material, and water. The specific preparation method is as follows, and the amount of each raw material added is in parts by mass:

[0056] Two parts of hydroxypropyl methylcellulose polymeric gel matrix, 20 parts of barium chloride-water phase change material, and 80 parts of water were stirred at 500 r / min for 30 min at room temperature and then loaded into a cold storage and heat exchange device 201 to obtain a phase change cold storage material with a thickness of 10 cm.

[0057] The daytime radiation cooling coating is placed on top of the cold storage heat exchange device 201 with an opening at the top, so that the phase change cold storage material inside the cold storage heat exchange device 201 can directly contact the aluminum plate at the bottom of the daytime radiation cooling coating, thereby achieving the cooling of the phase change cold storage material by the daytime radiation cooling coating.

[0058] The working principle and method of the frozen soil heat pipe structure in this embodiment are as follows:

[0059] According to the requirements, a permafrost roadbed heat pipe system with a radiation cooling coupling phase change module is inserted into the permafrost foundation. The heat pipe 1 contains a liquid cooling section, an evaporation section, a transition section and a heat dissipation section from bottom to top. When inserting the permafrost heat pipe structure into the permafrost foundation, the liquid cooling section and the evaporation section are inserted into the permafrost foundation.

[0060] The liquid cooling section of the heat pipe stores liquid refrigerant and circulates heat within it. After absorbing heat from the frozen soil subgrade, the liquid refrigerant vaporizes in the evaporation section, rises, and carries away the heat. Upon reaching the transition section, it transforms from a liquid to a gaseous refrigerant. In the heat dissipation section at the top of the heat pipe, the gaseous refrigerant achieves efficient heat exchange with the phase change storage material in the cold storage heat exchange device and the atmospheric environment through heat exchange fins, thus recondensing from a gaseous state back into a liquid state.

Claims

1. A permafrost heat pipe structure with vacuum enhanced radiative refrigeration coupled phase change modules, characterized in that, The device includes a heat pipe (1) and a vacuum-enhanced radiation cooling coupled phase change module (2) disposed on the top of the heat pipe (1). The vacuum-enhanced radiation cooling coupled phase change module (2) includes a cold storage heat exchange device (201), a daytime radiation cooling layer (202) laid on the upper surface of the cold storage heat exchange device (201), a heat insulation layer (203) disposed on the side wall and bottom periphery of the cold storage heat exchange device (201), a vacuum shell layer (204) disposed on the periphery of the heat insulation layer (203), and an optical window (205) disposed on the upper surface of the daytime radiation cooling layer (202). The vacuum shell layer (204) and the optical window (205) are sealed together to form a vacuum environment. The top of the heat pipe (1) extends into the interior of the cold storage heat exchange device (201) and contacts the phase change cold storage material stored in the cold storage heat exchange device (201).

2. The permafrost heat pipe structure with vacuum enhanced radiation refrigeration coupled phase change module of claim 1, wherein, The heat pipe (1) is also provided with a heat exchange fin assembly (101) on the outer periphery of the top. The heat exchange fin assembly (101) extends into the interior of the cold storage heat exchange device (201) and comes into contact with the phase change cold storage material stored in the cold storage heat exchange device (201).

3. The structure of the frozen soil heat pipe with the phase change module coupled with the vacuum enhanced radiative refrigeration according to claim 1, characterized in that, The heat pipe (1) is also provided with a heat exchange fin assembly (101) on the outer periphery of the top. The upper half of the heat exchange fin assembly (101) extends into the interior of the cold storage heat exchange device (201) and contacts the phase change cold storage material stored in the cold storage heat exchange device (201). The lower half of the heat exchange fin assembly (101) is outside the cold storage heat exchange device (201) and contacts the atmospheric environment.

4. The frozen soil heat pipe structure with vacuum enhanced radiation refrigeration coupled phase change module according to any one of claims 1-3, characterized in that, The daytime radiation cooling layer (202) is a daytime radiation cooling coating, a daytime radiation cooling film, a daytime radiation cooling paint, or a daytime radiation cooling fabric.

5. The structure of the frozen soil heat pipe with the phase change module coupled with the vacuum enhanced radiative refrigeration according to claim 4, characterized in that, The phase change cold storage material stored in the cold storage and heat exchange device (201) is composed of a polymer gel matrix, a phase change material and water. The polymer gel matrix is ​​one or a combination of hydroxypropyl methylcellulose, methylcellulose or carboxymethylcellulose. The phase change material is one or a combination of barium chloride-water system, glycine complex glycerol, n-tetane or water-mixed potassium sorbate.

6. The permafrost heat pipe structure with vacuum enhanced radiation refrigeration coupled phase change module of claim 5, wherein, The insulation layer (203) is made of phenolic foam material, expanded vitrified microspheres, rubber and plastic insulation material or glass wool.

7. The structure of the frozen soil heat pipe with the phase change module coupled with the vacuum enhanced radiative refrigeration according to claim 6, characterized in that, The optical window (205) is a highly transparent optical window, made of highly transparent glass or ZnS.

8. The permafrost heat pipe structure with a vacuum-enhanced radiative cooling coupled phase change module according to claim 7, characterized in that, The heat pipe (1) contains, from bottom to top, a liquid cooling section, an evaporation section, a transition section and a heat dissipation section.

9. The structure of the frozen soil heat pipe with the phase change module coupled with the vacuum enhanced radiative refrigeration according to claim 8, characterized in that, The liquid refrigeration section is used to store liquid refrigerant and circulate heat in the heat pipe. After absorbing heat from the frozen soil, the liquid refrigerant absorbs heat and vaporizes from the evaporation section, rising and carrying away heat. When it reaches the transition section, it is converted from liquid refrigerant to gaseous refrigerant. The gaseous refrigerant exchanges heat with the phase change cold storage material in the cold storage and heat exchange device (201) in the heat dissipation section, or exchanges heat with the phase change cold storage material in the cold storage and heat exchange device (201) or the atmospheric environment through the heat exchange fin assembly (101), and recondenses from gaseous to liquid.

Images