Organic Rankine cycle cooling system based on phase change microcapsule suspension

Abstract

The present invention discloses an organic Rankine cycle cooling system based on a phase change microcapsule suspension, wherein the output end of a circulation pump a is connected to a heat exchange pipeline, a condenser, a circulation pump b, a regenerator, and an input end of a circulation pump a through pipelines in sequence to form a closed circulation loop, the input end of the regenerator is also connected to the output end of a one-way valve, and the input end of the one-way valve is connected to the pipeline at the inlet of the condenser, and all pipelines are filled with a phase change microcapsule suspension; the phase change temperature of the phase change microcapsule suspension is lower than the critical operating temperature of electronic components, and cooling of a microelectronic system is achieved by combining an organic Rankine cycle with the phase change microcapsule suspension, which has a better cooling effect than traditional cooling methods and has higher operating safety.

Description

Technical Field

[0001] The invention belongs to the technical field of phase change cooling equipment, and in particular relates to an organic Rankine cycle cooling system based on a phase change microcapsule suspension. Background Art

[0002] With the rapid development of micro-electromechanical systems, various large-capacity and high-performance servers have become indispensable units in the era of big data. As the central brain of the server, the CPU is also highly dependent on temperature. Studies have shown that for every 1°C increase in CPU temperature, its reliability decreases by about 25%. At present, air cooling is the main cooling method used in the microelectronics industry. Whether it is a small home computer or a large server involving massive computing, the cooling method used is mostly air cooling. This is because compared with water cooling or other cooling methods, air cooling is simpler in structure, consumes less energy and has a large cooling area. Another more important reason is that the sensitivity of electronic components to conductive liquids makes water cooling and other methods difficult to implement in practical applications. The specific heat of water at room temperature and pressure is 4.2kJ / kg, which is much less than its latent heat of 2260kJ / kg. Therefore, when used as a circulating cooling medium, the heat exchange capacity of water working below its phase change temperature range is much less than its heat exchange capacity working at the phase change temperature. The maximum operating temperature of electronic components generally does not exceed 90°C, and it is difficult for working medium water to reach its phase change temperature. Electronic components are relatively small in size. In order to increase the contact area, the cooling pipe size is also relatively small. Millimeter-level variable cross-section microchannels are often used for heat exchange. The resulting pressure drop loss makes the pressure difference between the front and rear ends of the microchannel large, and the pressure inside the microchannel changes dramatically. The requirements for the pressure resistance of the condensation system material have also increased, which makes microchannel water cooling face great difficulties in practical applications. In fact, the cooling effect of the existing chip water cooling mode is not much different from that of air cooling, but its cost is higher than that of air cooling; and the heat dissipation capacity of air cooling is low, so it is difficult to apply it to the heat dissipation of future high heat flux density microelectronic systems. The technical structure of microchannel water cooling is relatively complex. Summary of the invention

[0003] The purpose of the present invention is to provide an organic Rankine cycle cooling system based on phase change microcapsule suspension, which performs phase change cooling on a microelectronic system through solid-liquid phase change to improve the heat dissipation of the microelectronic system.

[0004] The technical solution adopted by the present invention is an organic Rankine cycle cooling system based on a phase change microcapsule suspension, in which the output end of a circulating pump a is connected to a heat exchange pipeline, a condenser, a circulating pump b, a regenerator, and an input end of a circulating pump a through pipelines in sequence to form a closed circulation loop, the input end of the regenerator is also connected to the output end of a one-way valve, and the input end of the one-way valve is connected to the pipeline at the inlet of the condenser, and all pipelines are filled with a phase change microcapsule suspension.

[0005] The present invention is also characterized in that:

[0006] The phase-change microcapsule suspension comprises water and phase-change microcapsules, and the mass fraction of the phase-change microcapsules is 20-30%.

[0007] The phase-change microcapsules are spherical in shape and have a particle size of 310-320 nm.

[0008] The phase-change microcapsule comprises a core material and a wall material coated outside the core material, the wall material is melamine resin, the thickness of the wall material is 35-42nm, and the core material is n-octadecane.

[0009] The melting point of the phase change microcapsule is 24.56~30.72℃.

[0010] The working fluid channel inside the heat exchange pipeline adopts a "U" shape or a "Z" shape.

[0011] The beneficial effects of the present invention are:

[0012] The present invention is an organic Rankine cycle cooling system based on a phase change microcapsule suspension. The phase change temperature of the phase change microcapsule suspension is lower than the critical operating temperature of the electronic components. The cooling of the microelectronic system is achieved through the combination of the organic Rankine cycle and the phase change microcapsule suspension. Compared with traditional cooling methods, the cooling effect is better and the operation safety is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of an organic Rankine cycle cooling system based on a phase change microcapsule suspension of the present invention;

[0014] Figure 2 It is a schematic diagram of the phase change microcapsule structure of the present invention.

[0015] In the figure, 1. wall material, 2. core material, 3. heat exchange pipeline, 4. condenser, 5. regenerator, 6. check valve, 7. circulation pump a, 8. circulation pump b. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] The organic Rankine cycle cooling system based on phase change microcapsule suspension of the present invention is used to cool down electronic components in microelectronic systems, such as Figure 1As shown, the output end of the circulation pump a7 is connected to the heat exchange pipeline 3, the condenser 4, the circulation pump b8, the regenerator 5, and the input end of the circulation pump a7 through pipelines in sequence (the output end of each of the above components is connected to the input end of another component) to form a closed circulation loop, the input end of the regenerator 5 is also connected to the output end of the one-way valve 6, and the input end of the one-way valve 6 is connected to the pipeline at the inlet of the condenser 4. All pipelines are filled with phase change microcapsule suspensions, wherein the heat exchange pipeline 3 is a heat exchange pipeline belonging to the microelectronic system, and the heat exchange pipeline adopts a "U"-shaped or "Z"-shaped channel to increase the heat exchange time and heat exchange amount, so that the phase change microcapsules in the suspension reach the phase change temperature in the heat exchange tube and The heat exchange pipeline is subjected to phase change cooling from partial phase change to complete phase change. The condenser 4 is used to cool the phase change microcapsule suspension therein and condense it into a supercooled solution. The one-way valve 6 flows the high-temperature solution before entering the condenser 4 into the regenerator 5. The regenerator 5 receives the flowing solutions in two pipelines, one is the supercooled solution obtained after the condenser 4 passes through the circulation pump b8, and the other is the high-temperature solution passed through the one-way valve 6. After the high-temperature solution and the supercooled solution are mixed in the regenerator 5, a supercooled solution with a supercooling degree of 5-10°C can be obtained, that is, a phase change microcapsule suspension with a solid core material, and then enters the input end of the circulation pump a7 through the output end of the regenerator 5 for the next cycle cooling.

[0018] The phase-change microcapsule suspension includes water and phase-change microcapsules. The mass fraction of the phase-change microcapsules is 20-30%. The phase-change microcapsule suspension within this mass fraction range has a higher convection heat transfer coefficient and a higher heat storage performance.

[0019] The phase-change microcapsules are spherical in shape and have a particle size of 310-320 nm.

[0020] like Figure 2 As shown, the phase change microcapsule includes a core material 1 and a wall material 2 coated outside the core material 1, the wall material 2 is melamine resin, the thickness of the wall material 2 is 35-42nm, and the core material 1 is n-octadecane; the phase change microcapsule will have a speed difference with the mainstream, move back and forth in the mainstream, increase the turbulence of the mainstream, thereby enhancing the convective heat transfer coefficient of the wall surface, and in addition, due to the low melting point of the organic working fluid, phase change is easy to occur, further enhancing the heat exchange with the mainstream and improving the cooling effect.

[0021] The melting point of the phase change microcapsule is 24.56-30.72°C, which is the melting point of n-octadecane. The melting temperature of n-octadecane is lower than the limiting operating temperature of microelectronic components in the microelectronic system, so that n-octadecane melts to achieve the effect of phase change cooling; in addition, melamine resin has good water resistance, high thermal stability, strong low-temperature curing ability and good wear resistance.

[0022] The working medium channel inside the heat exchange pipeline 3 adopts a "U" shape or a "Z" shape, which can increase the heat exchange time and heat exchange amount between the microelectronic system and the flowing working medium.

[0023] The working process of the organic Rankine cycle cooling system based on phase change microcapsule suspension of the present invention is as follows:

[0024] When in use, the circulation pump a7 and the circulation pump b8 are turned on, and the heat exchange pipeline of the microelectronic system performs phase change heat exchange with the phase change microcapsule suspension passing therethrough, and the microelectronic system is cooled to obtain a high-temperature solution. A part of the high-temperature solution enters the condenser 4 for cooling to obtain a supercooled solution, which enters the regenerator 5 through the circulation pump b8, and the other part enters the regenerator 5 through the one-way valve 6. The supercooled solution is mixed with the other part of the high-temperature solution to obtain a supercooled solution with a supercooling degree of 5-10°C, and then enters the input end of the circulation pump a7 through the output end of the regenerator 5 for the next circulation cooling.

[0025] The core material of the phase change microcapsule in the phase change microcapsule suspension of the present invention is n-octadecane. After heat exchange in the heat exchange pipeline 3, the core material can be melted to perform phase change heat transfer. After the n-octadecane changes from the solid phase to the liquid phase, it will continue to heat up in the liquid phase until the phase change microcapsule suspension flows out of the heat exchange pipeline 3. The n-octadecane in the phase change microcapsule suspension after passing through the regenerator 5 is in a solid phase. In the present invention, all pipelines contain phase change microcapsule suspensions, but the state of the n-octadecane changes after passing through different components.

[0026] Through the above method, an organic Rankine cycle cooling system based on a phase change microcapsule suspension utilizes the phase change temperature of the phase change microcapsule suspension being lower than the critical operating temperature of electronic components. The cooling of the microelectronic system is achieved through the combination of the organic Rankine cycle and the phase change microcapsule suspension. Compared with traditional cooling methods, the cooling effect is better and the operation safety is higher.

Claims

1. Organic Rankine cycle cooling system based on phase change microcapsule suspension, characterized in that: The output end of the circulation pump a (7) is connected to the heat exchange pipeline (3), the condenser (4), the circulation pump b (8), the regenerator (5), and the input end of the circulation pump a (7) in sequence through pipelines to form a closed circulation loop, the input end of the regenerator (5) is also connected to the output end of the one-way valve (6), and the input end of the one-way valve (6) is connected to the pipeline at the inlet of the condenser (4), and all pipelines are filled with phase change microcapsule suspension; The phase-change microcapsule suspension comprises water and phase-change microcapsules, and the mass fraction of the phase-change microcapsules is 20%-30%; The phase-change microcapsules are spherical in shape and have a particle size of 310nm-320nm; The melting point of the phase change microcapsule is 24.56°C to 30.72°C; The phase-change microcapsule comprises a core material (1) and a wall material (2) coated outside the core material (1); the wall material (2) is melamine resin; the thickness of the wall material (2) is 35nm-42nm; and the core material (1) is n-octadecane.

2. The organic Rankine cycle cooling system based on phase change microcapsule suspension according to claim 1, characterized in that: The working medium channel inside the heat exchange pipeline (3) is in a "U" shape or a "Z" shape.

Images