Evaporator and refrigeration system

Abstract

The present invention relates to the field of refrigeration technology, and specifically discloses an evaporator and a refrigeration system. The evaporator is formed with a cooling medium cavity and a refrigerant cavity that can realize heat exchange with each other through a heat exchange wall. The cooling medium cavity is used for the circulation of liquid cooling medium, and the refrigerant cavity is used for the circulation of refrigerant; at least part of the wall surface of the heat exchange wall facing the refrigerant cavity is provided with a hydrophilic surface and a hydrophobic surface, and the hydrophilic surface and the hydrophobic surface are alternately distributed, and the hydrophobic surface can serve as a vaporization core to make the liquid refrigerant in the refrigerant cavity form bubbles of refrigerant vapor. Using the evaporator provided by the present invention, the hydrophobic surface can serve as a vaporization core to promote the rapid nucleation of bubbles in the early stage. In addition, the alternatingly distributed hydrophilic surface and hydrophobic surface help to accelerate the detachment of bubbles, thereby strengthening the pool boiling two-phase heat exchange and improving the heat exchange performance of the evaporator.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration technology, and more specifically, to an evaporator and a refrigeration system. Background Art

[0002] The evaporator is an important part of the refrigeration system. It is a type of heat exchanger that can convert liquid into gas. In the adsorption refrigeration system, the evaporator is the heat exchange component in the adsorption refrigerator, and its heat transfer capacity affects the heat transfer performance of the entire system.

[0003] In the process of implementing this application, the inventors found that there are at least the following problems in the prior art:

[0004] Taking the immersed evaporator as an example, the cooling medium tube is submerged in the liquid refrigerant. Due to the hydraulic pressure of the static liquid, it is difficult for the conventional cooling medium tube to boil and evaporate, resulting in a low boiling heat transfer coefficient of the shell side pool, so the heat exchange performance of the evaporator is poor. Summary of the invention

[0005] In view of this, an object of the present invention is to provide an evaporator and a refrigeration system, the structural design of which can effectively solve the problem of poor heat exchange performance of the evaporator.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] An evaporator is formed with a cooling medium cavity and a refrigerant cavity capable of realizing heat exchange with each other through a heat exchange wall, the cooling medium cavity is used for the circulation of liquid cooling medium, and the refrigerant cavity is used for the circulation of refrigerant;

[0008] The heat exchange wall faces at least a portion of the wall surface of the refrigerant cavity and is provided with a hydrophilic surface and a hydrophobic surface, and the hydrophilic surface and the hydrophobic surface are alternately distributed, and the hydrophobic surface can serve as a vaporization core to form bubbles of refrigerant vapor from the liquid refrigerant in the refrigerant cavity.

[0009] Optionally, in the above evaporator, the heat exchange wall is provided with micro-nano pits on at least part of the wall surface of the refrigerant chamber, the hydrophobic surface includes the inner surface of the micro-nano pits, and the hydrophilic surface includes the wall surface around the micro-nano pits.

[0010] Optionally, in the above evaporator, the wall surfaces other than the micro-nano pits are all the hydrophilic surfaces.

[0011] Optionally, in the above evaporator, the wall surface is provided with a plurality of the micro-nano pits distributed in an array.

[0012] Optionally, in the above evaporator, the width of the micro-nano pits gradually increases from the bottom to the top opening.

[0013] Optionally, in the above evaporator, the width of the micro-nano pits ranges from 50 to 150 μm; and / or, the depth of the micro-nano pits ranges from 30 to 80 μm; and / or, the spacing between adjacent micro-nano pits ranges from 150 to 250 μm.

[0014] Optionally, in the above evaporator, the hydrophilic surface includes a hydrophilic coating provided on the wall surface, and the hydrophobic surface includes a hydrophobic coating provided on the wall surface.

[0015] Optionally, in the above evaporator, the hydrophilic surface is a micro-nano hydrophilic surface, and / or the hydrophobic surface is a micro-nano hydrophobic surface.

[0016] Optionally, the above evaporator includes:

[0017] Equipment housing;

[0018] A cooling medium tube, wherein the cooling medium cavity is formed in the cooling medium tube, the cooling medium tube is arranged in the equipment shell, the refrigerant cavity is formed between the equipment shell and the cooling medium tube, and at least part of the outer wall of the cooling medium tube is provided with the hydrophilic surface and the hydrophobic surface.

[0019] The evaporator provided by the present invention is formed with a cooling medium cavity and a refrigerant cavity that can realize heat exchange with each other through a heat exchange wall. The cooling medium cavity is used for the circulation of liquid cooling medium; the refrigerant cavity is used for the circulation of refrigerant, and at least the wall surface of the heat exchange wall facing the refrigerant cavity is provided with a hydrophilic surface and a hydrophobic surface, and the hydrophilic surface and the hydrophobic surface are alternately distributed, and the hydrophobic surface can serve as a vaporization core to promote the rapid nucleation of the liquid refrigerant in the refrigerant cavity to form bubbles of refrigerant vapor.

[0020] The evaporator provided by the present invention mainly includes two parts of working medium flow, namely, cooling medium flow and refrigerant flow, and the liquid refrigerant can exchange heat with the cooling medium through the heat exchange wall. In the present application, by setting an alternatingly distributed hydrophilic surface and a hydrophobic surface on at least the wall surface of the heat exchange wall facing the refrigerant cavity, the hydrophobic surface can promote the rapid nucleation of bubbles at an early stage as the vaporization core. In addition, the alternatingly distributed hydrophilic surface and hydrophobic surface help to accelerate the detachment of bubbles, thereby strengthening the pool boiling two-phase heat exchange.

[0021] In summary, the present application provides an evaporator. Since the hydrophilic surface and the hydrophobic surface are alternately distributed, the hydrophobic surface is a favorable place for nurturing bubbles, which can effectively solve the problem that it is difficult for conventional bare tube bundles to boil and evaporate under the action of hydrostatic pressure, and can effectively improve the pool boiling heat transfer coefficient and enhance the heat exchange performance of the evaporator.

[0022] In order to achieve the above object, the present invention further provides a refrigeration system, which comprises any one of the above evaporators. Since the above evaporator has the above technical effects, the refrigeration system having the evaporator should also have corresponding technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a structural schematic diagram of an evaporator according to a specific embodiment of the present invention;

[0025] Figure 2 It is the mass transfer path for the liquid refrigerant to evaporate into refrigerant vapor;

[0026] Figure 3 It is a schematic structural diagram of a wall surface of a specific embodiment of the present invention;

[0027] Figure 4 for Figure 3 Schematic cross-section of .

[0028] Reference numerals:

[0029] 1-heat exchange wall; 11-wall surface; 2-cooling medium cavity; 3-refrigerant cavity; 111-hydrophilic surface; 112-hydrophobic surface; 113-micro-nano pits; d-width of micro-nano pits; h-depth of micro-nano pits; s-spacing between adjacent micro-nano pits;

[0030] 01-equipment housing, 02-cooling medium diverter device, 03-cooling medium flow conversion device, 04-tube sheet, 05-cooling medium pipe, 06-cooling medium, 071-liquid refrigerant; 072-refrigerant vapor; 011-refrigerant liquid return port, 012-refrigerant vapor outlet; 021-cooling medium inlet, 022-cooling medium outlet, 023-diverter baffle; 031-flow conversion baffle. DETAILED DESCRIPTION

[0031] The embodiment of the present invention discloses an evaporator and a refrigeration system to improve the heat exchange performance of the evaporator.

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The evaporator is a heat exchanger that absorbs heat from the cooling medium to be cooled flowing through the evaporator while allowing the refrigerant to evaporate from liquid to vapor, directly producing a heating or cooling effect. The evaporator provided in the present application can be used as, but not limited to, a heat exchanger in a vapor compression system or an adsorption refrigeration system.

[0034] See also Figure 1 and Figure 2 The evaporator provided in the present application is formed with a cooling medium cavity 2 and a refrigerant cavity 3 that can realize heat exchange with each other through a heat exchange wall 1. The cooling medium cavity 2 is used for the circulation of liquid cooling medium 06, and the refrigerant cavity 3 is used for the circulation of refrigerant. It can be understood that the shapes of the cooling medium cavity 2 and the refrigerant cavity 3 can be set as needed, and no specific limitation is made here. The cooling medium cavity 2 and the refrigerant cavity 3 can realize heat exchange between the cooling medium 06 in the cooling medium cavity 2 and the refrigerant in the refrigerant cavity 3 through the heat exchange wall 1.

[0035] The evaporator provided in the present application includes but is not limited to an immersion evaporator. In the immersion evaporator, please refer to Figure 1 The evaporator includes a device housing 01 and a cooling medium pipe 05, a cooling medium cavity 2 is formed in the cooling medium pipe 05, the cooling medium pipe 05 is arranged in the device housing 01, and a refrigerant cavity 3 is formed between the device housing 01 and the cooling medium pipe 05. The device housing 01 can provide a large accommodation space for the refrigerant, has high heat transfer efficiency, and is easy to clean. The shape of the device housing 01 can be set as needed, such as a square shell.

[0036] Exemplarily, the device housing 01 is provided with a refrigerant liquid return port 011 and a refrigerant vapor outlet 012. The refrigerant liquid return port 011 is used to connect to the condenser, and the refrigerant vapor outlet 012 is used to connect to the device for adsorbing vapor. A cooling medium diverter device 02 is provided on one side of the device housing 01, which is provided with a cooling medium inlet 021 and a cooling medium outlet 022. A diverter baffle 023 can be provided inside the cooling medium diverter device 02; a cooling medium flow diversion device 03 is provided on the other side of the device housing 01, and a flow diversion baffle 031 is provided inside the cooling medium flow diversion device 03. The diverter baffle 023 and the flow diversion baffle 031 can be set according to the number of pipe passes required for evaporation performance. Figure 1The number of pipe passes is 4. The cooling medium flow diversion device 02 and the cooling medium flow conversion device 03 are respectively assembled and connected with the equipment shell 01 to form an evaporator frame. Tube sheets 04 are respectively arranged at the connection between the cooling medium flow diversion device 02, the cooling medium flow conversion device 03 and the equipment shell 01. A cooling medium pipe group is arranged in the equipment shell 01. The tube sheet 04 is provided with tube sheet holes. Each cooling medium pipe 05 of the cooling medium pipe group is sealed and connected with the corresponding tube sheet hole. The cooling medium pipe 05 connects the cooling medium flow diversion device 02 and the cooling medium flow conversion device 03 to each other. Specifically, each cooling medium pipe 05 is staggered to facilitate the transmission and transportation of refrigerant vapor.

[0037] See also Figure 2 The cooling medium enters the cooling medium flow dividing device 2 from the cooling medium inlet 21, flows through the cooling medium pipe 05 to the cooling medium flow transfer device 3, and then flows from the cooling medium pipe 05 to the cooling medium flow dividing device 2, and the cycle continues until the cooling medium flows out of the evaporator from the cooling medium outlet 22. The liquid refrigerant 7 condensed by the condenser enters the evaporator from the refrigerant liquid return port 011, and the cooling medium pipe 05 in the evaporator is immersed in the liquid refrigerant 7.

[0038] Exemplarily, the cooling medium pipes 05 are arranged in multiple rows in the equipment housing 01, and the interval between adjacent cooling medium pipes 05 in a single row is 5 mm-7 mm, and the interval between adjacent rows is 9 mm-12 mm. The refrigerant liquid return port 011 and the refrigerant vapor outlet 012 are arranged at the top of the equipment housing 01, and a 10-15 mm refrigerant return channel is arranged between the cooling medium pipes 05 and the equipment housing 01 directly below the refrigerant liquid return port 011 and the refrigerant vapor outlet 012.

[0039] The inner side of the cooling medium pipe 05 performs single-phase countercurrent heat exchange, and the equipment shell 01 performs two-phase (pool boiling) heat exchange. Although phase change heat exchange occurs on the shell side, the flow rate is large due to the small diameter of the cooling medium pipe 05. Therefore, in a conventional bare tube submerged evaporator, the heat transfer coefficient on the shell side may be lower than that on the inner side of the tube. For example, the heat transfer coefficient on the inner side of the tube is about 2.6 times higher than that on the shell side. Therefore, how to improve the pool boiling heat transfer coefficient on the shell side is the key to improving the overall heat transfer performance of the submerged evaporator.

[0040] In the present application, at least a portion of the wall surface 11 of the heat exchange wall 1 facing the refrigerant chamber 3 is provided with a hydrophilic surface 111 and a hydrophobic surface 112, and the hydrophilic surface 111 and the hydrophobic surface 112 are alternately distributed, and the hydrophobic surface 112 can be used as a vaporization core to make the liquid refrigerant 071 in the refrigerant chamber 3 form bubbles of refrigerant vapor 072. Exemplarily, at least a portion of the outer wall of the cooling medium pipe 05 is provided with a hydrophilic surface 111 and a hydrophobic surface 112, that is, the outer wall of the cooling medium pipe 05 is used as the above-mentioned wall surface 11. The evaporator is provided with an alternately distributed hydrophilic surface 111 and a hydrophobic surface 112 on at least a portion of the wall surface 11 of the heat exchange wall 1 facing the refrigerant chamber 3. At least a portion of the wall surface 11 of the heat exchange wall 1 facing the refrigerant chamber 3 is different from a conventional metal surface, but is provided with an alternately distributed hydrophilic surface 111 and a hydrophobic surface 112. Exemplarily, through hydrophilic and hydrophobic treatment, at least a portion of the wall surface 11 exhibits alternatingly distributed hydrophilic and hydrophobic properties. In one example, the wall surface 11 is provided with an alternating hydrophilic surface 111 and a hydrophobic surface 112 as a whole. In another example, a portion of the wall surface 11 is provided with an alternating hydrophilic surface 111 and a hydrophobic surface 112. It is understood that the alternating distribution here means that at least one adjacent side of the hydrophilic surface 111 is provided with the hydrophobic surface 112, and at least one adjacent side of the hydrophobic surface 112 is provided with the hydrophilic surface 111.

[0041] Due to the low pressure in the evaporator, the evaporation temperature of the refrigerant is lower than the temperature of the cooling medium flowing in from the cooling medium inlet 21. The cooling medium tube 05 is partially immersed in the liquid refrigerant 7. When the cooling medium enters the cooling medium tube 05 from the cooling medium inlet 21, the heat of the cooling medium is transferred to the tube wall of the cooling medium tube 05 in turn, and the temperature of the cooling medium gradually decreases. The hydrophobic surface 112 on the outer wall surface of the cooling medium tube 05 serves as the vaporization core. The liquid refrigerant 7 absorbs heat and quickly forms bubbles on the hydrophobic surface 112. When the bubbles gradually grow along the hydrophobic surface 112, the hydrophilic surface 111 is conducive to the rapid replenishment of the liquid refrigerant 7, promotes the bubbles to quickly leave the wall 11, and realizes the rapid transfer of heat. The refrigerant vapor (dashed arrow) is as shown Figure 2 As shown, the refrigerant flows upward along the mass transfer channel and leaves the evaporator from the refrigerant vapor outlet 12. As the refrigerant continuously absorbs heat and evaporates, the temperature of the cooling medium continuously decreases, that is, the temperature of the cooling medium leaving the evaporator from the cooling medium outlet 22 is lower than the temperature when it flows into the evaporator from the cooling medium inlet 21, thereby achieving a refrigeration effect.

[0042] The evaporator provided by the present invention mainly includes two parts of working medium flow, namely, cooling medium 06 flow and refrigerant flow, and liquid refrigerant 071 can exchange heat with cooling medium 06 through heat exchange wall 1. In the present application, at least the wall surface 11 of heat exchange wall 1 facing refrigerant cavity 3 is provided with alternatingly distributed hydrophilic surface 111 and hydrophobic surface 112, and the hydrophobic surface 112 can promote the rapid nucleation of bubbles at an early stage as a vaporization core. In addition, the alternatingly distributed hydrophilic surface 111 and hydrophobic surface 112 help to accelerate the detachment of bubbles, thereby strengthening the pool boiling two-phase heat exchange.

[0043] In addition, the alternatingly distributed hydrophilic surface 111 and hydrophobic surface 112 can reduce the superheat of the heat exchange surface, where the superheat refers to the temperature of the heated wall minus the saturation temperature of the liquid. For example, for an evaporator with a smooth heat exchange wall, it needs to be heated to a first preset temperature under normal pressure to generate boiling bubbles and take away heat, while for the alternatingly distributed hydrophilic surface 111 and hydrophobic surface 112 in the present application, it only needs to be heated to a second preset temperature lower than the first preset temperature to generate a large number of boiling bubbles to take away heat.

[0044] In summary, the present application provides an evaporator. Since the hydrophilic surface 111 and the hydrophobic surface 112 are alternately distributed, the hydrophobic surface 112 is a favorable place for nurturing bubbles, which can effectively solve the problem that it is difficult for conventional bare tube bundles to boil and evaporate under the action of hydrostatic pressure, and can effectively improve the pool boiling heat transfer coefficient without adding internal devices and equipment of the evaporator, thereby improving the heat exchange performance of the evaporator.

[0045] The above embodiments mainly illustrate the structure of the immersed evaporator. In another embodiment, the evaporator includes a refrigerant tube and a cooling medium tube 05. A cooling medium cavity 2 is formed in the cooling medium tube 05. The cooling medium tube 05 is arranged in the refrigerant tube. A refrigerant cavity 3 is formed between the refrigerant tube and the cooling medium tube 05. The outer wall of the cooling medium tube 05 serves as the wall surface 11 with the hydrophilic surface 111 and the hydrophobic surface 112. The liquid refrigerant 071 is heated and evaporated on the outer wall of the cooling medium tube 05 to become refrigerant vapor 072. The refrigerant tube and the cooling medium tube 05 are nested, and the refrigerant tube is nested outside the cooling medium tube 05, which can also provide a higher heat exchange efficiency, and the structure is simple, and the evaporator occupies a small area. In this embodiment, the heat exchange wall 1 includes the tube wall of the cooling medium tube 05.

[0046] In another embodiment, the evaporator includes a refrigerant tube and a cooling medium tube 05, the cooling medium tube 05 is sleeved outside the refrigerant tube, a refrigerant cavity 3 is formed inside the refrigerant tube, a cooling medium cavity 2 is formed between the refrigerant tube and the cooling medium tube 05, the inner wall of the refrigerant tube serves as the wall surface 11 with the hydrophilic surface 111 and the hydrophobic surface 112, and the liquid refrigerant 071 evaporates on the inner wall of the refrigerant tube to become refrigerant vapor 072. In this embodiment, the refrigerant tube and the cooling medium tube 05 are sleeved, and the refrigerant tube is sleeved inside the cooling medium tube 05, and at this time, the heat exchange wall 1 includes the tube wall of the refrigerant tube.

[0047] In another embodiment, the evaporator includes a refrigerant tube and a cooling medium tube 05, the refrigerant tube and the cooling medium tube 05 are arranged in close contact, a refrigerant cavity 3 is formed in the refrigerant tube, a cooling medium cavity 2 is formed in the cooling medium tube 05, the inner wall of the refrigerant tube serves as the wall surface 11 with the hydrophilic surface 111 and the hydrophobic surface 112, and the liquid refrigerant 071 evaporates on the outer wall of the cooling medium tube 05 to become refrigerant vapor 072. In this embodiment, the heat exchange wall 1 includes the tube wall of the refrigerant tube and the tube wall of the cooling medium tube 05 that are in close contact.

[0048] In some embodiments, the hydrophilic surface 111 is a micro-nano hydrophilic surface, and / or the hydrophobic surface 112 is a micro-nano hydrophobic surface. In one example, the hydrophilic surface 111 is a micro-nano hydrophilic surface. In another example, the hydrophobic surface 112 is a micro-nano hydrophobic surface. In another example, the hydrophilic surface 111 is a micro-nano hydrophilic surface, and the hydrophobic surface 112 is a micro-nano hydrophobic surface. It is understood that the micro-nano hydrophilic surface refers to the size of the hydrophilic surface 111 is micron-scale or nanometer-scale, and the micro-nano hydrophobic surface refers to the size of the hydrophobic surface 112 is micron-scale or nanometer-scale. Exemplarily, the micro-nano hydrophilic surface and the micro-nano hydrophobic surface are alternately distributed, that is, the hydrophilic surface 111 of micrometer scale and the hydrophobic surface 112 of nanometer scale are alternately distributed, or the hydrophilic surface 111 of nanometer scale and the hydrophobic surface 112 of nanometer scale are alternately distributed, or the hydrophilic surface 111 of micrometer scale and the hydrophobic surface 112 of nanometer scale are alternately distributed, or the hydrophilic surface 111 of micrometer scale and the hydrophobic surface 112 of nanometer scale are alternately distributed. By setting at least one of the hydrophilic surface 111 and the hydrophobic surface 112 to be at the micro-nano level, the formation of a vapor film is avoided, which is more conducive to the detachment of the vapor bubbles.

[0049] In some embodiments, see Figure 3 and Figure 4, at least part of the wall surface 11 of the heat exchange wall 1 facing the refrigerant chamber 3 is provided with a micro-nano pit 113, the hydrophobic surface 112 includes the inner surface of the micro-nano pit 113, and the hydrophilic surface 111 includes the wall surface 11 around the micro-nano pit 113. The nucleation rate of the traditional smooth wall surface is slow. In the process of realizing the present application, the inventor found that the vaporization core is more likely to occur at the corner or edge of the microstructure, and the vaporization core is more likely to occur on the hydrophobic surface 112. Therefore, in this embodiment, the micro-nano pit 113 is provided on the wall surface 11, and the inner surface of the micro-nano pit 113 is set as the hydrophobic surface 112, that is, as a micro-nano hydrophobic surface, so as to facilitate vaporization nucleation in the pit, and the micro-nano pit 113 is not submerged by the liquid refrigerant as a gas cavity, which further helps to form a vaporization core. At the same time, the wall surface 11 around the micro-nano pit 113 adopts a hydrophilic surface 111. Exemplarily, the wall 11 is provided with a plurality of micro-nano pits 113, and the spacing between adjacent micro-nano pits 113 is in the micrometer level or nanometer level to form a micro-nano hydrophilic surface. In summary, through the provision of the micro-nano pits 113 and the hydrophilic and hydrophobic surface treatment, the micro-nano pits 113 as vaporization cores can promote the rapid nucleation of bubbles at an early stage, and the hydrophilic and hydrophobic micro-nano structure helps to accelerate the detachment of bubbles, thereby enhancing the pool boiling two-phase heat exchange.

[0050] In some embodiments, the wall surface 11 other than the micro-nano pits 113 is a hydrophilic surface 111. That is, the wall surface 11 of the heat exchange wall 1 facing the refrigerant chamber 3 except the micro-nano pits 113 is a hydrophilic surface 111. Exemplarily, the outer wall of the cooling medium tube 05 is treated hydrophilically to form a hydrophilic surface. Micro-nano pits 113 are formed on the outer wall of the cooling medium tube 05, and the inner surface of the micro-nano pits 113 is treated hydrophobically to form a hydrophobic surface. In this embodiment, after the bubbles formed by the evaporation of the liquid refrigerant 071 gradually grow along the hydrophobic surface 112 of the micro-nano pits 113, the large-scale hydrophilic surface 111 is more conducive to the rapid replenishment of the liquid refrigerant 7, thereby promoting the bubbles to quickly leave the wall surface 11.

[0051] In some embodiments, the wall surface 11 is provided with a plurality of micro-nano pits 113 distributed in an array. The micro-nano pits 113 are distributed in an array, which is convenient for forming and is conducive to forming uniformly distributed vaporization cores, thereby being more conducive to evaporation and boiling.

[0052] In some embodiments, the width of the micro-nano pit 113 gradually increases from the bottom to the top opening, so that the bubbles formed by the evaporation of the liquid refrigerant 071 can grow better along the hydrophobic surface 112 of the micro-nano pit 113 .

[0053] In some embodiments, the width d of the micro-nano pit 113 ranges from 50 to 150 μm, preferably, the width d of the micro-nano pit 113 ranges from 80 to 120 μm, and exemplary, the width d of the micro-nano pit 113 is 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm. The vaporization core is easy to occur on the hydrophobic surface, and it is more likely to occur in the corner or edge of the microstructure. If the width of the micro-nano pit 113 is too large, the bubble core is mainly concentrated on the edge of the micro-nano pit 113, causing the remaining hydrophobic surface of the micro-nano pit 113 to not become an effective vaporization area. At the same time, the hydrophobic surface cannot be wetted by the liquid. The excessive width of the micro-nano pit 113 occupies a large area of ​​the heat exchange wall, reducing the effective contact surface (hydrophilic surface) area between the liquid and the heat exchange wall, and failing to take away the heat in time. Therefore, setting the width of the micro-nano pits 113 within the above range can fully utilize the hydrophobic surface of the micro-nano pits 113 to form a vaporization core, and can ensure better contact and heat exchange between the liquid and the hydrophilic surface, thereby improving evaporation and boiling heat exchange.

[0054] The depth h of the micro-nano pit 113 ranges from 30 to 80 μm, preferably from 40 to 60 μm. Exemplarily, the depth h of the micro-nano pit 113 is 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm or 80 μm. If the depth of the micro-nano pit 113 is too large, the bubble core is mainly concentrated at the edge of the micro-nano pit 113, resulting in the remaining hydrophobic surface of the micro-nano pit 113 not becoming an effective vaporization area. Therefore, setting the depth of the micro-nano pit 113 within the above range can make full use of the hydrophobic surface of the micro-nano pit 113 to form a vaporization core, thereby improving the evaporation boiling heat exchange.

[0055] The spacing s between adjacent micro-nano pits 113 ranges from 150 to 250 μm, preferably from 180 to 220 μm. Exemplarily, the spacing s between adjacent micro-nano pits 113 is 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm or 250 μm. If the spacing between adjacent micro-nano pits 113 is too small, the bubbles generated on the surface are easy to merge during the growth process. When the bubbles are not separated from the wall, they merge to form larger bubbles, which are easy to form a steam film on the surface of the heat exchange wall. The insulation of the steam film makes it impossible for the heat of the heat exchange wall to be exchanged in time. Therefore, setting the spacing between adjacent micro-nano pits 113 within the above range is conducive to avoiding the formation of a steam film, thereby improving the heat exchange efficiency.

[0056] In summary, the micro-nano pits 113 adopt the above-mentioned design, which can serve as vaporization cores, promote rapid early nucleation of bubbles, and help bubble detachment, thereby improving the pool boiling heat transfer coefficient.

[0057] In some embodiments, micro-nano pits 113 are prepared on the wall 11 by micro-nano preparation techniques, such as electrochemical etching, laser ablation, etc., and then the micro-nano pits 113 and the surrounding walls 11 are selectively treated with hydrophilicity and hydrophobicity by chemical modification methods, such as self-assembled monolayers, sol-gel methods, etc., to form the above-mentioned hydrophilic surface 111 and hydrophobic surface 112.

[0058] In some embodiments, the hydrophilic surface 111 includes a hydrophilic coating provided on the wall surface 11, and the hydrophobic surface 112 includes a hydrophobic coating provided on the wall surface 11. The above embodiments illustrate that the micro-nano pits 113 are provided on the wall surface 11 and used as the hydrophobic surface 112. In this embodiment, the alternatingly distributed hydrophilic and hydrophobic surfaces, i.e., the hydrophilic coating and the hydrophobic coating, can also be directly formed by spraying, which can also promote the rapid nucleation of bubbles in the early stage, and the hydrophilic surface 111 and the hydrophobic surface 112 are easy to form. In one example, a plurality of hydrophilic coatings are provided on the wall surface 11, and a hydrophobic coating is provided on the wall surface 11 other than the plurality of hydrophilic coatings. In another example, a plurality of hydrophobic coatings are provided on the wall surface 11, and a hydrophilic coating is provided on the wall surface 11 other than the plurality of hydrophobic coatings.

[0059] In some embodiments, the hydrophilic surface 111 and / or the hydrophobic surface 112 are distributed in an array. The hydrophobic surface 112 is distributed in an array, which is convenient for molding and is conducive to forming uniformly distributed vaporization cores, thereby being more conducive to evaporation and boiling. Accordingly, the hydrophobic surface 112 is distributed in an array, which is convenient for molding and is conducive to the detachment of bubbles.

[0060] Based on the evaporator provided in the above embodiment, the present invention further provides a refrigeration system, which includes any one of the evaporators in the above embodiment. Since the refrigeration system adopts the evaporator in the above embodiment, please refer to the above embodiment for the beneficial effects of the refrigeration system.

[0061] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0062] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An evaporator, characterized in that: A cooling medium cavity (2) and a refrigerant cavity (3) are formed, which can realize heat exchange with each other through the heat exchange wall (1); the cooling medium cavity (2) is used for the circulation of liquid cooling medium (06), and the refrigerant cavity (3) is used for the circulation of refrigerant; At least a portion of the wall surface (11) of the heat exchange wall (1) facing the refrigerant cavity (3) is provided with a hydrophilic surface (111) and a hydrophobic surface (112), and the hydrophilic surface (111) and the hydrophobic surface (112) are alternately distributed, and the hydrophobic surface (112) can serve as a vaporization core to enable the liquid refrigerant (071) in the refrigerant cavity (3) to form bubbles of refrigerant vapor (072).

2. The evaporator according to claim 1, characterized in that At least a portion of the wall surface (11) of the heat exchange wall (1) facing the refrigerant cavity (3) is provided with a micro-nano pit (113), the hydrophobic surface (112) includes the inner surface of the micro-nano pit (113), and the hydrophilic surface (111) includes the wall surface (11) around the micro-nano pit (113).

3. The evaporator according to claim 2, characterized in that The wall surfaces (11) other than the micro-nano pits (113) are all the hydrophilic surfaces (111).

4. The evaporator according to claim 2, characterized in that The wall surface (11) is provided with a plurality of micro-nano pits (113) distributed in an array.

5. The evaporator according to any one of claim 2, characterized in that: The width of the micro-nano pit (113) gradually increases from the bottom to the top opening.

6. The evaporator according to any one of claims 2 to 5, characterized in that: The width of the micro-nano pit (113) is in the range of 50 to 150 μm; and / or the depth of the micro-nano pit (113) is in the range of 30 to 80 μm; and / or the spacing between adjacent micro-nano pits (113) is in the range of 150 to 250 μm.

7. The evaporator according to claim 1, characterized in that The hydrophilic surface (111) comprises a hydrophilic coating provided on the wall surface (11), and the hydrophobic surface (112) comprises a hydrophobic coating provided on the wall surface (11).

8. The evaporator according to claim 1, characterized in that The hydrophilic surface (111) is a micro-nano hydrophilic surface, and / or the hydrophobic surface (112) is a micro-nano hydrophobic surface.

9. The evaporator according to claim 1, characterized in that include: Equipment housing (01); A cooling medium tube (05), wherein the cooling medium cavity (2) is formed in the cooling medium tube (05), the cooling medium tube (05) is arranged in the device shell (01), the refrigerant cavity (3) is formed between the device shell (01) and the cooling medium tube (05), and at least part of the outer wall of the cooling medium tube (05) is provided with the hydrophilic surface (111) and the hydrophobic surface (112).

10. A refrigeration system, characterized in that: The evaporator comprises the evaporator as claimed in any one of claims 1 to 9.

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