Novel quick-response plate heat exchanger based on blade type phase change composite material

Abstract

The invention relates to a novel quick-response plate heat exchanger based on a blade type phase change composite material, and aims to solve the problems that a refrigerating system of existing high-power equipment is large in size, too large in weight, low in response speed and low in efficiency. Therefore, the novel fast-response efficient plate heat exchanger is obtained. Compared with a traditional heat exchanger system, the weight of the novel quick-response plate heat exchanger is reduced by more than 91%, the response time is short, and the novel quick-response plate heat exchanger can be popularized and applied to any high-power equipment as an independent integral heat exchange system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat management, in particular to a new fast-response plate heat exchanger based on a blade-type phase change composite material. BACKGROUND

[0002] With the multifunctionalization and high integration of power devices, the heat generation of electronic devices increases exponentially, and at the same time, the heat dissipation system becomes increasingly large. Especially for intermittent high-power equipment, the heat generation during work is extremely large, but it works periodically. The traditional liquid cooling heat exchanger uses a compressor and natural convection to achieve the purpose of heat dissipation. With the increase of heat dissipation demand during work, the demand for refrigerating capacity of the compression refrigerating unit increases dramatically, which makes the total amount of the refrigerating unit and the cooling liquid increase dramatically, and the high weight causes a burden to the entire equipment. The present application combines the traditional heat exchanger and the high-thermal-conductivity fast-response graphene-based phase change energy storage composite material, utilizes the phase change heat absorption characteristics of the phase change material, reduces the cooling liquid temperature of the equipment during work, and reduces the temperature below the phase change point of the phase change material during the interval of not working, and the phase change heat absorption occurs again during the next working period. Due to the heat storage effect of the phase change material, the power of the refrigerating unit and the volume of the cooling liquid can be greatly reduced. Therefore, the new plate heat exchanger obtained by combining the phase change energy storage material and the traditional heat exchanger is a revolutionary progress to solve the heat dissipation problem of intermittent high-power equipment.

[0003] Most of the intermittent working power devices have a working temperature of 50-80℃, so the high-stability organic phase change material is the first choice for preparing a new heat exchanger, but the thermal conductivity of the organic phase change material (such as paraffin) is low (less than 1 W / m.K), and the temperature conduction is slow, which leads to slow phase change speed. Therefore, the high-thermal-conductivity fast-response phase change energy storage material is also the key to obtain a new efficient plate heat exchanger. SUMMARY

[0004] In view of the problems of the traditional heat exchanger, such as large volume, excessive mass and low heat exchange efficiency, the present application provides a new fast-response plate heat exchanger based on a blade-type phase change composite material.

[0005] The technical scheme of the present application is as follows:

[0006] A new type of fast-response plate heat exchanger based on blade-type phase change composite material, characterized in that the heat exchanger is composed of a plate heat exchanger and a blade-type phase change composite material; the plate heat exchanger includes a plurality of flat-plate flow plates arranged in parallel, one end of the flat-plate flow plate is connected to the water inlet tank, and the other end of the flat-plate flow plate is connected to the water outlet tank, wherein the connection method can be mechanical connection or welding. The inlet tank is provided with a coolant inlet, and the outlet tank is provided with a coolant outlet. Flat-plate flow channels are arranged in parallel and welded to a base plate. Support structures are provided at regular intervals between adjacent flat-plate flow channels to form flow channel gaps. The blade-shaped phase change composite material is a composite of carbon-based foam or metal foam and phase change material. The blade-shaped phase change composite material is inserted into the flow channel gap of a heat exchanger, similar to a "blade battery." The blade-shaped phase change composite material is in close contact with the flow channel plate walls of the flow channel gap. The contact surfaces of the flow channel plate walls with the blade-shaped phase change composite material are bonded with a high-resistance thermal interface material or coated with a paste-like thermal interface material to reduce interfacial thermal resistance. The coolant outlet is connected to a radiator. It should be noted that although the inlet and outlet tanks are referred to as tanks, they are essentially containers that can hold a cooling medium. The cooling medium is not limited to water and can be any coolant, such as water, ethylene glycol, an ethylene glycol aqueous solution, propylene glycol, a propylene glycol aqueous solution, mineral oil, or synthetic oil. Phase change materials can be selected from but are not limited to organic phase change materials, metal phase change materials, etc., as long as the phase change material has good phase change energy storage performance.

[0007] Furthermore, the flow channels in the flat-plate flow channel plate are in the shape of a harmonica tube, a rectangle or any other shape.

[0008] Furthermore, the heat conduction direction of the blade-type phase change composite material with a higher thermal conductivity is perpendicular to the flow channel plate wall.

[0009] Furthermore, the support structure can be made of plate material, preferably an I-shaped support. The wall thickness of the flow channel in the flat-plate flow channel plate can preferably be 0.5-2.0 mm. The flat-plate flow channel can be made of steel, copper and its alloys, aluminum and its alloys, etc., with aluminum or aluminum alloys being preferred for lightness and cost.

[0010] Furthermore, the carbon-based material foam may be graphene foam, carbon foam, graphite foam, carbon nanotube foam, etc., preferably graphene foam, etc.; the metal foam may be aluminum foam, aluminum alloy foam, copper foam, copper alloy foam, nickel foam, nickel alloy foam, etc.

[0011] Furthermore, the type of radiator is not particularly limited; for example, a finned radiator or any other type of radiator can be selected. The radiator can also be replaced by other refrigeration equipment, such as a compressor for cooling. Furthermore, the radiator can be used in conjunction with other refrigeration equipment, connected to a fan or other refrigeration equipment. Any refrigeration method, such as a compressor, can be used as the refrigeration equipment.

[0012] Furthermore, to facilitate cooling the phase change material to below its transition temperature when the power device is not operating, a semiconductor cooling plate can be installed in the plate heat exchanger, either in the outlet water tank or on the heat exchanger. The installation of a semiconductor cooling plate is optional and is not required, depending on the phase change temperature characteristics of the phase change material. For example, if the phase change temperature of the phase change material is high or the cooling requirement is low, the semiconductor cooling plate can be omitted.

[0013] Furthermore, it is preferred that the blade-type phase change composite material is a blade-type graphene-based phase change composite material obtained by compounding graphene foam and phase change material. The blade-type graphene-based phase change composite material used in the novel heat exchanger has a composite structure of highly oriented graphene foam and phase change material, and its specific preparation method comprises the following steps:

[0014] (1) Graphene / ice crystal mixtures are assembled layer by layer based on low-temperature 3D printing technology: the preparation environment temperature is -40°C to -10°C, and the graphene / ice crystal mixtures assembled layer by layer are cooled from above by liquid nitrogen. Due to the shearing effect of the extruder during the assembly process, the graphene sheets are highly oriented; the overall ambient temperature is controlled to regulate the size of the ice crystals;

[0015] (2) freeze-drying to remove ice crystals and obtain graphene foam;

[0016] (3) Graphene foam degreasing: degreasing temperature ≥ 350 °C to remove polymer dispersant;

[0017] (4) Secondary orientation and density control of graphene foam: The degreased graphene foam is pressed twice by a pressure device to obtain graphene foams of different densities and porosities. This process promotes the secondary orientation of graphene nanosheets and makes the final graphene foam pore size between 100 nanometers and 10 microns, and the porosity is adjustable between 70% and 95%;

[0018] (5) Graphene foam graphitization treatment: treatment temperature is 2500℃~3200℃, treatment time is 0.5-5h;

[0019] (6) Composite of graphene foam and phase change material: Graphene foam and phase change material are composited by a perfusion device. The temperature is raised to above the phase transition point of the phase change material, and the graphene foam is placed. The graphene foam and phase change material are efficiently composited by combining vacuum negative pressure and positive pressure introduced by a protective gas. Vacuum negative pressure and positive pressure are alternately cycled 1-10 times until the composite rate reaches 100%. The protective gas can be nitrogen, argon, helium or other inert gases. The perfusion device is preferably a high-temperature perfusion device that can withstand high operating temperatures.

[0020] Furthermore, the graphene layer in step (1) is highly oriented by at least one of ice template orientation, magnetic field induced orientation, and pressure induced orientation.

[0021] This application also provides a method for preparing the novel plate heat exchanger, the preparation steps of which include:

[0022] (1) Plate heat exchanger structure design: According to the use requirements, input parameters and design the specific structure of the plate heat exchanger, including heat storage design, coolant flow design, coolant temperature design, flat channel plate design, support structure spacing design, etc., to obtain a plate heat exchanger structure that meets the use requirements;

[0023] (2) Plate heat exchanger electrical and control design: Based on the working structure requirements of the actual application, the control system and electrical system of the plate heat exchanger are designed to achieve the regulation and control of the flow, pressure and temperature of the heat exchanger. (3) Plate heat exchanger processing: Based on the design structure, the main material of the plate heat exchanger is selected. For example, aluminum alloy can be used as the main material of the plate heat exchanger. The plate heat exchanger is processed and formed through 3D printing technology, mechanical processing or welding technology, and the flow channel wall is polished after processing;

[0024] (4) Preparation of blade-type phase change composite materials: Carbon-based material foam or metal foam is compounded with phase change material to obtain blade-type phase change composite materials. For example, blade-type graphene-based phase change composite materials can be prepared according to the above-mentioned preparation method.

[0025] (5) Processing and assembly: The blade-shaped phase change composite material is processed according to the structure of the plate heat exchanger and assembled into the flow channel interval of the plate heat exchanger. The surface of the flow channel plate wall is bonded with a high-resilient thermal interface material or coated with a paste-like thermal interface material to reduce the interface thermal resistance. It is preferred that the graphene orientation direction is perpendicular to the flow channel plate wall during assembly, and an interference fit method can be used. Thermal interface materials such as thermal grease, thermal silica gel, and thermal gel are preferred.

[0026] (6) Welding the upper cover: After assembling the phase change composite material, weld the upper cover. The welding points include the cover around the plate and local welding points, such asFigure 3 As shown, the local welding point is the upper surface of the coolant flow channel plate. Each flat flow channel plate can be welded with 2-5 welding points on the upper surface. In order to prevent the phase change energy storage material from gasifying during the welding process and affecting the welding effect, cold water is passed through the heat exchanger during the welding process to reduce the overall temperature. The cold water inlet temperature is 10-40℃.

[0027] The beneficial effects of the present invention are as follows: 1. It greatly reduces the volume and weight of the refrigeration unit: Due to the phase change heat absorption effect of the phase change material, the cooling water consumption and the power of the refrigeration unit can be reduced; at the same efficiency, the weight of the new plate heat exchanger is reduced by more than 90% compared with the original refrigeration unit. 2. It has the advantage of fast response speed: by controlling the arrangement direction of the foam material, for example, when graphene foam is used, the arrangement direction of the graphene is controlled to obtain highly oriented graphene foam with a thermal conductivity of more than 150W / mK; by controlling the temperature to control the size of the ice crystals during the preparation process, and by controlling the pore size through secondary density regulation, the graphene foam has a submicron pore size. The small pore size reduces the transmission path of heat from the heat-conducting skeleton to the phase change material, thereby achieving a fast response of the graphene-based phase change energy storage composite material; the introduction of the fast-response phase change energy storage composite material makes the entire new heat exchanger have the characteristic of fast response speed, which is 2 / 3 faster than that without the phase change energy storage composite material. 3. Universal applicability: The new plate heat exchanger prepared by the present invention can be used on any other large-scale equipment that works intermittently, and is applicable to scenarios such as roadbed, airborne, and satellite-borne. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the plate heat exchanger structure (without blade-type phase change composite material installed);

[0029] Figure 2 Schematic diagram of a new fast-response plate heat exchanger based on blade-type graphene-based phase change composite materials;

[0030] Figure 3 A typical heat exchanger upper cover welding diagram;

[0031] Figure 4 Macroscopic photograph of the internal structure of the plate heat exchanger in Example 1;

[0032] Notes in the figure: 1-water inlet tank, 2-exhaust port, 3-coolant inlet, 4-I-shaped support, 5-coolant outlet, 6-water outlet tank, 7-semiconductor refrigeration plate, 8-radiator, 9-harmonica tube-shaped flat flow channel plate, 10-upper cover, 11-blade-type graphene-based phase change composite material, 12-graphene nanosheet, 13-welding point. DETAILED DESCRIPTION

[0033] The following will be combined with the accompanying drawings and specific embodiments to clearly and completely describe the technical solutions in the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, and are not all implementation methods of the technical solutions in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] A new type of fast response plate heat exchanger based on blade-type phase change composite material, characterized in that the heat exchanger is composed of a plate heat exchanger and a blade-type phase change composite material; its typical structure is as follows Figure 1 As shown, the flat plate heat exchanger includes a plurality of flat plate flow channel plates arranged in parallel, and the flat plate flow channel plates are harmonica tube-shaped flat plate flow channel plates 9, one end of the harmonica tube-shaped flat plate flow channel plate 9 is connected to the water inlet tank 1, and the other end of the harmonica tube-shaped flat plate flow channel plate 9 is connected to the water outlet tank 6, wherein the connection method can be mechanical connection or welding. A coolant inlet 3 is provided on the water inlet tank 2, and a coolant outlet 5 is provided on the water outlet tank 2; the flat plate flow channel plates are arranged in parallel and welded on the bottom plate, and an I-shaped support 4 is provided at a certain distance between adjacent flat plate flow channel plates to form a flow channel interval; in this embodiment, the blade-type phase change composite material uses a blade-type graphene-based phase change composite material, and the blade-type phase change composite material is obtained by compounding a graphene phase change composite material. As shown Figure 2 As shown, the blade-type graphene-based phase change composite material 11 is similar to a "blade battery" inserted into the flow channel interval of the heat exchanger; the blade-type graphene-based phase change composite material 11 is in close contact with the flow channel plate wall of the flow channel interval, and the surface of the flow channel plate wall in contact with the blade-type fast-response phase change composite material is bonded with a high-elasticity thermal interface material or coated with a paste-like thermal interface material to reduce the interface thermal resistance; the coolant outlet is connected to the radiator 8. Preferably, in this embodiment, the new fast-response plate heat exchanger based on the blade-type phase change composite material is provided with an upper cover plate 10 located on the side, an exhaust port 2 is provided at the upper end of the water inlet tank 1, and the radiator 8 or the water outlet tank is also connected to the semiconductor refrigeration plate 7. In addition, according to work requirements, the radiator 8 can also be connected to refrigeration equipment such as a fan or a compressor.

[0036] Although graphene foam is used as the matrix of the blade-type phase change composite material in this embodiment, alternatives include carbon foam, graphite foam, carbon nanotube foam, or metal foams, such as aluminum foam, aluminum alloy foam, copper foam, copper alloy foam, nickel foam, or nickel alloy foam. These alternatives can also effectively improve heat exchange efficiency and reduce the volume and weight of the heat exchanger. However, from the perspective of further reducing weight and improving heat exchange efficiency, carbon-based foam matrices, such as graphene foam, are preferred.

[0037] Taking a certain period of equipment as an example, the specific preparation method of a new fast-response plate heat exchanger based on blade-type graphene-based phase change composite materials is explained. The specific process is as follows:

[0038] (1) Plate heat exchanger structure design: According to the use requirements, the heating power of the device is 4000W, the working time is 10 minutes, the ambient temperature is 60℃, and the working interval is 1h. According to the above parameters, the heat storage capacity of the plate heat exchanger is designed to be 2500kJ, the fluid flow rate is 20L / min, the width of a single harmonica tube-shaped flat plate flow channel plate is 100mm, the thickness is 2mm, and there are 12 rectangular flow channels side by side in a single harmonica tube-shaped flat plate flow channel plate. The size of each flow channel is 8×1mm, and the wall thickness of the flow channel is 0.5mm. The distance between two adjacent harmonica tube-shaped flat plate flow channel plates is 80mm. The distance between two adjacent support structures between two adjacent harmonica tube-shaped flat plate flow channel plates is 120mm. The support structure is an I-shaped support. The graphene-based phase change energy storage composite material selected is graphene foam with a porosity of 70%. The phase change point of the phase change material is 62-65℃. The coolant is ethylene glycol aqueous solution. The heat dissipation power of the radiator is not less than 700W.

[0039] (2) Plate heat exchanger electrical and control design: Based on the working structure requirements of the actual application, the control system and electrical system of the plate heat exchanger are designed to monitor the temperature, flow rate and pressure of different positions of the heat exchanger, radiator and coolant, thereby controlling the start and stop of the radiator and circulation pump and reporting an alarm to the superior system;

[0040] (3) Plate heat exchanger processing: According to the design structure, aluminum alloy is generally selected as the main material of the plate heat exchanger. The plate heat exchanger is processed and formed by metal 3D printing technology, and the flow channel wall is polished after processing; (4) Graphene-based phase change energy storage composite materials are prepared according to the following steps:

[0041] a) Assembling a graphene / ice crystal mixture layer by layer using low-temperature 3D printing technology: The preparation environment temperature is -40°C, and the assembled graphene / ice crystal mixture 9 is cooled from above by liquid nitrogen. Due to the shearing effect of the extruder during the assembly process, the graphene sheets are highly oriented; the overall ambient temperature is controlled to regulate the size of the ice crystals;

[0042] b) freeze-drying the graphene / ice crystal mixture for 5 days to remove the ice crystals to obtain graphene foam; heating can preferably be performed by radiant heating;

[0043] c) Graphene foam degreasing: Degreasing in a degreasing furnace at 700°C for 2 h to remove the polymer dispersant;

[0044] d) Secondary orientation and density control of graphene foam: The degreased graphene foam was placed in a pressing mold and pressed twice by a press to obtain a porosity of 70% and a density of 0.63 g / cm 3 This process promotes the secondary orientation of graphene nanosheets 12, with a pore size of about 400 nm and an orientation degree of 0.7; the microstructure of graphene nanosheets 12 is as follows Figure 2 As shown;

[0045] e) Graphene foam graphitization treatment: treatment temperature is 3200°C, treatment time is 0.5h;

[0046] f) Composite of graphene foam and phase change material: Graphene foam and phase change material were composited using a high-temperature infusion device. The temperature was raised to 80°C, all the paraffin phase change material was melted, and the graphene foam was placed in the device. The device was evacuated for 1.5 hours, and then nitrogen was introduced and positive pressure was applied for 1.5 hours. The vacuum and negative pressure were alternately cycled for 1-10 times until the composite rate reached 100% and the thermal conductivity of the composite phase change material reached 150 W / mK.

[0047] (5) Processing and assembly: The graphene-based phase change energy storage composite material is processed according to the structure of the plate heat exchanger and assembled into the flow channel gap of the plate heat exchanger. The wall of the flow channel plate is coated with thermal conductive silicone grease to reduce the interface thermal resistance. The thermal conductivity of the thermal conductive silicone grease is 18W / mK. During assembly, the direction of graphene orientation is perpendicular to the flow channel plate wall (such as Figure 2 As shown in the figure), an interference fit method is used to further reduce the interface thermal resistance.

[0048] (6) Welding the upper cover plate: After assembling the phase change composite material, the upper cover plate 10 is welded by cold welding. The welding points 13 on the surface of the plate heat exchanger include the cover plate and local welding points, such as Figure 3 As shown, the local welding point is the upper surface of the flat-plate flow channel plate. There are two welding points on the upper surface of each flat-plate flow channel plate. In order to prevent the phase change energy storage material from gasifying during the welding process and affecting the welding effect, cold water is passed through the heat exchanger during the welding process to reduce the overall temperature. The cold water inlet temperature is 10°C.

[0049] The internal structure of the plate heat exchanger in this embodiment is shown in the following figure: Figure 4 As shown, it can be seen that the surface of the phase change material is smooth and is tightly integrated with the plate heat exchanger.

[0050] The new, high-efficiency plate heat exchanger and refrigeration system prepared in this example weighs a total of 49 kg. A refrigeration system without phase change materials would weigh 600 kg, a 91% weight reduction. The entire system was tested for heat exchange using an ethylene glycol aqueous solution as the coolant. A heating plate was used to provide a 4000W power output, and the temperatures at the water inlet and outlet were measured to determine the heat exchange efficiency. The test found that after 10 minutes of heating, the overall test temperature was below the water outlet temperature by less than 65°C, consistent with the design value. There was no overheating, and the overall response time was 6 minutes.

[0051] Example 2

[0052] The structure of the novel fast-response plate heat exchanger based on blade-type phase-change composite materials in this embodiment is substantially the same as that in Embodiment 1.

[0053] The specific preparation method of the novel fast-response plate heat exchanger based on blade-type graphene-based phase change composite materials in this embodiment is described using equipment operating in a certain cycle as an example. The specific process is as follows:

[0054] (1) Plate heat exchanger structure design: According to the use requirements, the heating power of the device is 4000W, the working time is 10 minutes, the ambient temperature is 60℃, and the working interval is 1h. According to the above parameters, the heat storage capacity of the plate heat exchanger is designed to be 2500kJ, the fluid flow rate is 20L / min, the width of a single harmonica tube-shaped flat plate flow channel plate is 100mm, the thickness is 2mm, and there are 12 rectangular flow channels side by side in a single harmonica tube-shaped flat plate flow channel plate. The size of each flow channel is 8×1mm, and the wall thickness of the flow channel is 0.5mm. The distance between two adjacent harmonica tube-shaped flat plate flow channel plates is 80mm. The distance between two adjacent support structures between two adjacent harmonica tube-shaped flat plate flow channel plates is 120mm. The support structure is I-shaped. The graphene-based phase change energy storage composite material selected is graphene foam with a porosity of 95%. The phase change point of the phase change material is 62-65℃. The coolant is ethylene glycol aqueous solution. The heat dissipation power of the finned radiator is not less than 700W.

[0055] (2) Plate heat exchanger electrical and control design: Based on the working structure requirements of the actual application, the control system and electrical system of the plate heat exchanger are designed to monitor the temperature, flow rate and pressure at different positions of the heat exchanger, radiator and coolant, thereby controlling the start and stop of the radiator and circulation pump and alarming the superior system.

[0056] (3) Plate heat exchanger processing: According to the design structure, aluminum alloy is selected as the main material of the plate heat exchanger. The plate heat exchanger is processed and formed through welding process, and the flow channel wall is polished after processing;

[0057] (4) Prepare a graphene-based phase change energy storage composite material according to the following steps:

[0058] a) Graphene / ice crystal hybrids are assembled layer by layer using low-temperature 3D printing technology: The preparation environment is kept at -10°C, and the assembled graphene / ice crystal mixture is cooled from above using liquid nitrogen. Due to the shearing action of the extruder during the assembly process, the graphene sheets achieve high orientation. The overall ambient temperature is controlled to regulate the size of the ice crystals.

[0059] b) freeze-drying the graphene / ice crystal mixture for 4 days to remove the ice crystals by radiative heating to obtain graphene foam;

[0060] c) Graphene foam degreasing: Degreasing in a degreasing furnace at 350°C for 5 h to remove the polymer dispersant;

[0061] d) Secondary orientation and density control of graphene foam: The degreased graphene foam was placed in a pressing mold and pressed twice by a press to obtain a porosity of 95% and a density of 0.1 g / cm 3 ,This process promotes the secondary orientation of graphene nanosheets 12, with a pore size of about 5 μm and an orientation degree of 0.5;

[0062] e) Graphene foam graphitization treatment: treatment temperature is 2800°C, treatment time is 4h;

[0063] f) Composite of graphene foam and phase change material: Graphene foam and phase change material were composited using a high-temperature infusion device. The temperature was raised to 80°C, all the paraffin phase change material was melted, and the graphene foam was placed in the mixture. The mixture was evacuated for 1.5 hours, and then nitrogen was introduced and positive pressure was applied for 1.5 hours. The vacuum and negative pressure were alternately cycled for 1-10 times until the composite rate reached 100% and the thermal conductivity of the composite phase change material reached 10 W / mK.

[0064] (5) Processing and assembly: The graphene-based phase change energy storage composite material is processed according to the structure of the plate heat exchanger and assembled into the flow channel interval of the plate heat exchanger. The flow channel plate wall uses a graphene flexible thermal conductive pad as the thermal interface material with a thermal conductivity of 12W / mK. During assembly, the graphene orientation direction is perpendicular to the flow channel plate wall (such as Figure 2 As shown in Figure 2, an interference fit method is used to further reduce the interface thermal resistance.

[0065] (6) Welding the upper cover: After assembling the phase change composite material, the upper cover is welded by cold welding. The welding points 13 on the surface of the plate heat exchanger include the cover and local welding points, such as Figure 3 As shown, the local welding points are located on the upper surface of the flat plate, with five welding points on each plate. To prevent the phase change energy storage material from vaporizing during welding and affecting the welding effect, cold water is passed through the heat exchanger to lower the overall temperature. The cold water inlet temperature is set at 40°C.

[0066] The new, high-efficiency plate heat exchanger and refrigeration system prepared in this example weighs a total of 48 kg. A refrigeration system without phase change materials weighs 600 kg, a 92% weight reduction. The entire system was tested for heat exchange using an ethylene glycol-water solution as the coolant. Using a heating plate providing a 4000W power output, the inlet and outlet temperatures were measured to determine heat exchange efficiency. Testing revealed that after 10 minutes of heating, the overall test temperature remained below the outlet temperature by less than 65°C, consistent with the design value. There was no overheating, and the overall response time was 10 minutes.

[0067] Example 3

[0068] The structure of the novel fast-response plate heat exchanger based on blade-type phase-change composite materials in this embodiment is substantially the same as that in Embodiment 1.

[0069] The specific preparation method of the novel fast-response plate heat exchanger based on blade-type graphene-based phase change composite materials in this embodiment is described using equipment operating in a certain cycle as an example. The specific process is as follows:

[0070] (1) Plate heat exchanger structure design: According to the use requirements, the heating power of the device is 4000W, the working time is 10 minutes, the ambient temperature is 60℃, and the working interval is 1h. According to the above parameters, the cooling capacity of the plate heat exchanger is designed to be 2500kJ, the fluid flow rate is 20L / min, the width of a single harmonica tube-shaped flat plate flow channel plate is 100mm, the thickness is 2mm, and there are 12 rectangular flow channels side by side in a single harmonica tube-shaped flat plate flow channel plate. The size of each flow channel is 8×1mm, and the wall thickness of the flow channel is 0.5mm. The distance between two adjacent harmonica tube-shaped flat plate flow channel plates is 80mm. The distance between two adjacent support structures between two adjacent harmonica tube-shaped flat plate flow channel plates is 120mm. The support structure is I-shaped. The graphene-based phase change energy storage composite material selected is graphene foam with a porosity of 85%. The phase change point of the phase change material is 62-65℃. The coolant is ethylene glycol aqueous solution. The heat dissipation power of the radiator is not less than 750W.

[0071] (2) Plate heat exchanger electrical and control design: Based on the working structure requirements of the actual application, the control system and electrical system of the plate heat exchanger are designed to monitor the temperature, flow rate and pressure at different positions of the heat exchanger, radiator and coolant, thereby controlling the start and stop of the radiator and circulation pump and alarming the superior system.

[0072] (3) Plate heat exchanger processing: According to the design structure, aluminum alloy is selected as the main material of the plate heat exchanger. The plate heat exchanger is processed and formed by direct machining technology, and the flow channel wall is polished after processing; (4) Graphene-based phase change energy storage composite materials are prepared according to the following steps:

[0073] a) Graphene / ice crystal hybrids are assembled layer by layer using low-temperature 3D printing technology: The preparation environment is kept at -30°C, and the assembled graphene / ice crystal mixture is cooled from above using liquid nitrogen. Due to the shearing action of the extruder during the assembly process, the graphene sheets achieve high orientation. The overall ambient temperature is controlled to regulate the size of the ice crystals.

[0074] b) freeze-drying the graphene / ice crystal mixture for 5 days to remove the ice crystals by radiative heating to obtain graphene foam;

[0075] c) Graphene foam degreasing: Degreasing in a degreasing furnace at 500°C for 3 h to remove the polymer dispersant;

[0076] d) Secondary orientation and density control of graphene foam: The degreased graphene foam was placed in a pressing mold and pressed twice by a press to obtain a porosity of 85% and a density of 0.3 g / cm 3 ,This process promotes the secondary orientation of graphene nanosheets 12, with a pore size of about 1 micron and an orientation degree of 0.6;

[0077] e) Graphene foam graphitization treatment: treatment temperature is 3000°C, treatment time is 2h;

[0078] f) Composite of graphene foam and phase change material: Graphene foam and phase change material were composited using a high-temperature infusion device. The temperature was raised to 80°C, all the paraffin phase change material was melted, and the graphene foam was placed in the mixture. The mixture was evacuated for 1.5 hours, and then nitrogen was introduced and positive pressure was applied for 1.5 hours. The vacuum and negative pressure were alternately cycled for 1-10 times until the composite rate reached 100% and the thermal conductivity of the composite phase change material reached 50 W / mK.

[0079] (5) Processing and assembly: The graphene-based phase change energy storage composite material is processed according to the structure of the plate heat exchanger and assembled into the flow channel interval of the plate heat exchanger. The wall of the flow channel plate is coated with thermal conductive silicone grease to reduce the interface thermal resistance. The thermal conductivity of the thermal conductive silicone grease is 18W / mK. During assembly, the direction of graphene orientation is perpendicular to the flow channel plate wall (such as Figure 2 As shown in Figure 2, an interference fit method is used to further reduce the interface thermal resistance.

[0080] (6) Welding the upper cover: After assembling the phase change composite material, the upper cover is welded by cold welding. The welding points 13 on the surface of the plate heat exchanger include the cover and local welding points, such as Figure 3 As shown, the local welding points are located on the upper surface of the flat plate, with three welding points on each plate. To prevent the phase change energy storage material from vaporizing during welding and affecting the welding effect, cold water is passed through the heat exchanger to lower the overall temperature during welding. The cold water inlet temperature is set at 25°C.

[0081] The new, high-efficiency plate heat exchanger and refrigeration system prepared in this example weighs a total of 50 kg. A refrigeration system without phase change materials weighs 600 kg, a 91% weight reduction. The entire system was tested for heat exchange using an ethylene glycol aqueous solution as the coolant. Using a heating plate providing a 4000W power output, the inlet and outlet temperatures were measured to determine heat exchange efficiency. The test revealed that after 10 minutes of heating, the overall test temperature remained below the outlet temperature by less than 66°C, consistent with the design value. There was no overheating, and the overall response time was 8 minutes.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A new type of fast response plate heat exchanger based on blade-type phase change composite material, characterized in that: The heat exchanger is composed of a plate heat exchanger and a blade-type phase change composite material; the plate heat exchanger includes a plurality of flat-plate flow channel plates arranged in parallel, one end of the flat-plate flow channel plate is connected to the water inlet tank, and the other end of the flat-plate flow channel plate is connected to the water outlet tank, the water inlet tank is provided with a coolant inlet, and the water outlet tank is provided with a coolant outlet; the flat-plate flow channel plates are arranged in parallel and welded on the bottom plate, and a supporting structure is provided at a certain distance between adjacent flat-plate flow channel plates to form a flow channel interval; the blade-type phase change composite material is obtained by compounding carbon-based material foam or metal foam with phase change material, and the blade-type phase change composite material is inserted into the flow channel interval; the blade-type fast-response phase change composite material is in close contact with the flow plate wall of the flow channel interval, and the contact surface of the flow plate wall and the blade-type phase change composite material is bonded with a high-elasticity thermal interface material or smeared with a paste-like thermal interface material to reduce the interface thermal resistance; The water outlet tank is connected to the radiator.

2. The novel fast-response plate heat exchanger based on blade-type phase change composite material according to claim 1 is characterized in that: The flow channels in the flat flow channel plate are harmonica tube-shaped.

3. A novel fast-response plate heat exchanger based on blade-type phase change composite materials according to claim 1 or 2, characterized in that: The heat conduction direction of the blade-type phase change composite material with higher thermal conductivity is perpendicular to the flow channel wall.

4. A novel fast-response plate heat exchanger based on blade-type phase change composite materials according to claim 1 or 2, characterized in that: The support structure is an I-shaped support, and / or the wall thickness of the flow channel in the flat flow channel plate is 0.5-2.0 mm; and / or the flat flow channel plate is made of aluminum or aluminum alloy.

5. A novel fast-response plate heat exchanger based on blade-type phase change composite material according to claim 1 or 2, characterized in that: The carbon-based material foam is graphene foam or carbon foam; the metal foam is aluminum foam, aluminum alloy foam, copper foam or copper alloy foam.

6. A novel fast-response plate heat exchanger based on blade-type phase change composite materials according to claim 1 or 2, characterized in that: The radiator is connected to a fan or cooling device.

7. The novel fast-response plate heat exchanger based on blade-type phase change composite material according to claim 1 or 2, characterized in that: The blade-type phase change composite material is a blade-type graphene-based phase change composite material obtained by compounding graphene foam and phase change material. The blade-type graphene-based phase change composite material has a composite structure of highly oriented graphene foam and phase change material. The preparation method of the blade-type graphene-based phase change composite material includes the following steps: (1) Graphene / ice crystal mixtures are assembled layer by layer based on low-temperature 3D printing technology: the preparation environment temperature is -40°C to -10°C, and the graphene / ice crystal mixtures assembled layer by layer are cooled from above by liquid nitrogen. Due to the shearing effect of the extruder during the assembly process, the graphene sheets are highly oriented; the overall ambient temperature is controlled to regulate the size of the ice crystals; (2) freeze-drying to remove ice crystals and obtain graphene foam; (3) Graphene foam degreasing: degreasing temperature ≥ 350 °C to remove polymer dispersant; (4) Secondary orientation and density control of graphene foam: The degreased graphene foam is pressed twice by a pressure device to obtain graphene foams of different densities and porosities. This process promotes the secondary orientation of graphene nanosheets and makes the final graphene foam pore size between 100 nanometers and 10 microns, and the porosity is adjustable between 70% and 95%; (5) Graphene foam graphitization treatment: treatment temperature is 2500℃~3200℃, treatment time is 0.5-5h; (6) Composite of graphene foam and phase change material: Graphene foam and phase change material are composited by a perfusion device, the temperature is raised to above the phase change point of the phase change material, and graphene foam is placed. The graphene foam and phase change material are efficiently composited by combining vacuum negative pressure and positive pressure with the help of protective gas. Vacuum negative pressure and positive pressure are alternately performed for 1-10 cycles until the composite rate reaches 100%.

8. The novel fast-response plate heat exchanger based on blade-type phase-change composite material according to claim 7, characterized in that: The graphene layer in step (1) is highly oriented by adopting at least one of ice template orientation, magnetic field induced orientation, and pressure induced orientation.

9. A method for preparing a novel fast-response plate heat exchanger based on a blade-type phase-change composite material according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) Plate heat exchanger structure design: According to the use requirements, input parameters and design the specific structure of the plate heat exchanger, including heat storage design, coolant flow design, coolant temperature design, flat channel plate design, and support structure spacing design, to obtain a plate heat exchanger structure that meets the use requirements; (2) Plate heat exchanger electrical and control design: Based on the working structure requirements of the actual application, the control system and electrical system of the plate heat exchanger are designed to achieve the regulation and control of the heat exchanger flow, pressure and temperature; (3) Plate heat exchanger processing: According to the design structure, the main material of the plate heat exchanger is selected, and the plate heat exchanger is processed and formed through 3D printing technology, mechanical processing or welding process. The flow channel wall is polished after processing; (4) Preparation of blade-type phase change composite materials: carbon-based material foam or metal foam is compounded with phase change material to obtain blade-type phase change composite materials; (5) Processing and assembly: Process the blade-type phase change energy storage composite material according to the structure of the plate heat exchanger, and assemble the processed blade-type phase change energy storage composite material into the flow channel interval of the plate heat exchanger, wherein the surface of the flow channel plate wall is bonded with high resilience thermal interface material or coated with paste thermal interface material to reduce the interface thermal resistance. (6) Welding the upper cover: After assembling the phase change composite material, weld the upper cover. The welding points include the cover around the cover and local welding points. The local welding points are the upper surface of the flat-plate flow channel plate. There are 2-5 welding points on the upper surface of each flat-plate flow channel plate. During the welding process, cold water is passed through the heat exchanger to reduce the overall temperature. The cold water inlet temperature is 10-40℃.

10. The method for preparing a novel fast-response plate heat exchanger based on blade-type phase change composite materials according to claim 9, characterized in that: In the processing and assembly of step (5), during assembly, the graphene is oriented in a direction perpendicular to the flow channel plate wall, and the assembly is performed using an interference fit method.

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