All-weather nanofluid-based radiation refrigeration device

Abstract

The invention provides a radiation refrigeration plate combining a sky radiation refrigeration material and a plate heat exchanger, and relates to the technical field of refrigeration, the radiation refrigeration plate comprises a sky radiation refrigeration material layer, a plate heat exchanger assembly, a fan cover layer and a heat insulation material layer, the sky radiation refrigeration material layer has high reflectivity in a solar spectrum wave band and has high emissivity in an atmospheric window wave band, and the plate heat exchanger assembly has high reflectivity in a heat insulation material layer; and heat can be efficiently radiated to the outer space. The plate heat exchanger assembly comprises an enhanced heat exchange tube and a nanofluid, and the nanofluid is filled in the enhanced heat exchange tube and used for heat transfer and transport capacity and enhancing the heat exchange effect. And the fan cover covers the sky radiation refrigeration material. The heat insulation material layer is laid on the portion, except the top face, of the radiation refrigeration plate so as to reduce heat loss of the system to the surrounding environment, and the refrigeration effect is guaranteed. By means of the structure, working modes in the daytime and at night are achieved, the heat transfer efficiency of the system is greatly improved, energy consumption is reduced, and the efficient radiation refrigeration effect of all-weather continuous operation at the temperature lower than the environment temperature is achieved.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and in particular to a radiant refrigeration plate combining a sky radiant refrigeration material with a plate heat exchanger. Background Art

[0002] With the continuous growth of energy demand and increasing attention to environmental issues, traditional refrigeration technology faces many problems such as high energy consumption and limited refrigeration efficiency. Therefore, improving the efficiency of existing refrigeration systems and exploring new refrigeration technologies have become urgent issues to be solved. Sky radiation cooling technology is a process that uses objects on the earth's surface (temperature is about 300K) to radiate heat to outer space (temperature is about 3K) through the "atmospheric window" band (mainly 8-13μm) to achieve cooling. This technology does not require additional energy input. However, relying solely on sky radiation cooling technology, it is difficult to meet actual needs under certain working conditions. Enhanced heat exchange technology can effectively increase the heat transfer rate, but most of the existing enhanced heat exchange methods rely on additional energy input, which is contrary to the original intention of energy saving. Therefore, combining sky radiation cooling materials with efficient plate heat exchangers to develop a new type of radiation cooling plate has important practical significance and application value. Summary of the invention

[0003] Purpose of the Invention The object of the present invention is to provide a radiation cooling plate combining a sky radiation cooling material with a plate heat exchanger to achieve a radiation cooling effect below the ambient temperature during the day and at night.

[0004] Technical Solutions In view of this, the present invention provides a radiant cooling plate combining a sky radiant cooling material with a plate heat exchanger, comprising: A sky radiation cooling material layer, wherein the sky radiation cooling material has high reflectivity in the solar spectrum band (0.3-2.5 μm) and high emissivity in the atmospheric window band (8-13 μm), and can efficiently radiate heat to outer space.

[0005] A plate heat exchanger assembly, the plate heat exchanger assembly comprising an enhanced heat exchange tube and a nanofluid. The enhanced heat exchange tube is composed of a copper tube embedded in an aluminum plate, and the copper tube has a micro-rib structure, which disrupts the flow of the nanofluid, breaks the stability of the boundary layer, and causes the nanofluid to form turbulence in the tube, and the heat transfer is faster. The presence of the micro-rib structure increases the contact area between the nanofluid and the tube wall of the enhanced heat exchange tube, thereby improving the heat exchange efficiency. The enhanced heat exchange tube is evenly distributed under the sky radiation cooling material and is in close contact with the sky radiation cooling material. The nanofluid is filled in the enhanced heat exchange tube, and the nanofluid has a high thermal conductivity and thermal diffusion coefficient, which can effectively improve the heat transfer and transport capacity and enhance the heat exchange effect.

[0006] A wind shield layer is provided above the sky radiation cooling material to reduce the influence of external air convection on the sky radiation cooling material, reduce convection heat loss, and improve radiation cooling efficiency.

[0007] The heat-insulating material layer is laid on the portion of the radiant cooling panel other than the top surface to reduce the heat loss of the system to the surrounding environment and ensure the cooling effect.

[0008] Technical Effects In the technical solution of the present invention, a radiation cooling plate combining a sky radiation cooling material and a plate heat exchanger is provided.

[0009] During daytime operation, the sky radiative cooling material absorbs solar radiation (P sun ) and from atmospheric radiation (P atm ), and the sky radiation cooling material will emit thermal radiation outward (P rad ) and the cooling loss of the radiation cooling material (P loss ). The sky radiation cooling material transfers the cold to the enhanced heat exchange tube below, and the nanofluid in the enhanced heat exchange tube transfers and transports the cold to achieve a cooling effect during the day.

[0010] During nighttime operation, the sky radiative cooling material absorbs atmospheric radiation (P atm ), and the sky radiation cooling material itself will still radiate heat outward (P rad ) and the cooling loss of sky radiation cooling materials (P loss ). Consistent with the daytime operation, the sky radiation cooling material transfers the cold to the enhanced heat exchange tube below, and the nanofluid in the enhanced heat exchange tube transfers and transports the cold to achieve a cooling effect at night.

[0011] Through the above-mentioned daytime and nighttime working modes, the system greatly improves the heat transfer efficiency, reduces energy consumption and achieves a high-efficiency radiation cooling effect below the ambient temperature that operates continuously around the clock. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic structural diagram of an all-weather nanofluid-based radiation cooling device described in the present invention.

[0013] Figure 2 This is an overall top view of an all-weather nanofluid-based radiation cooling device described in the present invention.

[0014] Figure 3 This is an overall isometric view of an all-weather nanofluid-based radiant cooling device according to the present invention.

[0015] Figure 4This is a diagram showing the internal structure of the enhanced heat exchange tubes of an all-weather nanofluid-based radiation refrigeration device described in the present invention.

[0016] Among them: 1. Radiant refrigeration materials; 2. Enhanced heat exchange tubes; 3. Aluminum plates; 4. Micro-rib structures; 5. Nanofluids; 6. Insulation materials; 7. Wind hoods. DETAILED DESCRIPTION

[0017] An embodiment of the present invention provides an all-weather nanofluid-based radiation cooling device, as shown in the accompanying drawings, comprising a sky radiation cooling material 1, an enhanced heat exchange tube 2, an aluminum plate 3, a micro-rib structure 4, a nanofluid 5, an insulation material 6, and a wind hood 7.

[0018] Specifically, the sky radiation cooling material 1 generates cold energy through sky radiation cooling, transfers heat to the enhanced heat exchange tube 2, and then transfers and transports the cold energy through the nanofluid 5 in the enhanced heat exchange tube 2. In this process, the micro-rib structure 4 in the enhanced heat exchange tube disrupts the flow of the nanofluid 5, breaks the stability of the boundary layer, and makes the nanofluid 5 form turbulence in the tube, and the heat transfer is faster. In addition, the presence of the micro-rib structure 4 can significantly increase the contact area between the nanofluid 5 and the wall of the enhanced heat exchange tube 2, so that the nanofluid 5 has more opportunities to exchange heat with the wall of the enhanced heat exchange tube 2, thereby improving the heat exchange efficiency. The insulation material 6 reduces the cold loss of the system to the surrounding environment and ensures the cooling effect. The wind hood 7 covers the sky radiation cooling material to reduce the impact of external air convection on the sky radiation cooling material, reduce convection heat loss, and improve the radiation cooling efficiency.

[0019] In the technical solution of an embodiment of the present invention, an all-weather nanofluid-based radiation cooling device is provided. The nanofluid-based radiation cooling plate has a sky radiation cooling material 1, an enhanced heat exchange tube 2, a micro-fin structure 4, a nanofluid 5, an insulation material 6, and a wind cover 7.

Claims

1. An all-weather nanofluid-based radiative cooling device, characterized in that: include: It includes a sky radiation cooling material layer, a plate heat exchanger assembly, a wind shield layer and a heat insulation material layer; A sky radiation cooling material layer, wherein the sky radiation cooling material (1) has high reflectivity in the solar spectrum band (0.3-2.5 μm) and high emissivity in the atmospheric window band (8-13 μm), and can efficiently radiate heat to outer space; A plate heat exchanger assembly, the plate heat exchanger assembly comprising an enhanced heat exchange tube (2) and a nanofluid (5), the enhanced heat exchange tube (2) being composed of a copper tube embedded in an aluminum plate (3), the copper tube having a micro-rib structure (4) therein, which disrupts the flow of the nanofluid (5), breaks the stability of the boundary layer, and causes the nanofluid (5) to form turbulence in the tube, so that heat transfer is more rapid, and the presence of the micro-rib structure (4) increases the contact area between the nanofluid (5) and the tube wall of the enhanced heat exchange tube (2), thereby improving the heat exchange efficiency, the enhanced heat exchange tube (2) being evenly distributed below the sky radiation cooling material and in close contact with the sky radiation cooling material (1), the nanofluid (5) being filled in the enhanced heat exchange tube (2), having a high thermal conductivity and thermal diffusion coefficient, and being able to effectively improve the heat transfer and transport capacity, and thus enhancing the heat exchange effect; A wind shield layer, wherein the wind shield (7) covers the sky radiation cooling material (1) to reduce the influence of external air convection on the radiation cooling material (1), reduce convection heat loss, and improve radiation cooling efficiency; The thermal insulation material layer (6) is laid on the portion of the radiation cooling plate other than the top surface, so as to reduce the cold loss of the system to the surrounding environment and ensure the cooling effect.

2. The nanofluid-based radiant cooling plate according to claim 1, characterized in that: The enhanced heat exchange tube (2) is provided with a micro-rib structure (4), and the micro-rib structure (4) can significantly increase the contact area between the nanofluid (5) and the tube wall of the enhanced heat exchange tube (2), thereby improving the heat exchange efficiency.

3. The nanofluid-based radiative cooling plate according to claim 1, characterized in that: The sky radiation cooling material (1) absorbs solar radiation (P sun ) and from atmospheric radiation (P atm ), and emits heat radiation (P rad ) and cooling loss (P loss ), transferring the cooling energy to the enhanced heat exchange tube (2) below; when operating at night, absorbing atmospheric radiation (P atm ), and radiates heat outwards (P rad ) and cooling loss (P loss ), and similarly transfers the cold to the enhanced heat exchange tube (2) below, thereby achieving a 24-hour cooling effect below the ambient temperature.

4. The nanofluid-based radiant cooling plate according to claim 1, characterized in that: The concentration and particle size of the nanofluid (5) are optimized to ensure good flow characteristics.

5. The nanofluid-based radiative cooling plate according to claim 1, characterized in that: A trace amount of surfactant is also added to the nanofluid (5) to improve the dispersibility and stability of the nanofluid and further improve the heat exchange performance.

6. The nanofluid-based radiative cooling plate according to claim 1, characterized in that: The sky radiation cooling material (1) and the enhanced heat exchange tube (2) are tightly connected via a heat conductive adhesive with good heat conductivity, so as to ensure that the cold energy can be efficiently transferred from the sky radiation cooling material (1) to the enhanced heat exchange tube (2).

7. The nanofluid-based radiative cooling panel according to claim 1, characterized in that: The shape and size of the channel of the enhanced heat exchange tube (2) are optimized to further improve the heat exchange efficiency.

8. The nanofluid-based radiative cooling plate according to claim 1, characterized in that: The density and porosity of the thermal insulation material (6) are optimized to ensure thermal insulation performance while taking into account its strength and weight.

Images