High temperature heat exchanger and thermo-acoustic power generation system

Abstract

The application provides a high-temperature heat exchanger and a thermoacoustic power generation system, wherein the high-temperature heat exchanger comprises a heat collecting part and a heat exchanging part; a plurality of slots are arranged on one end of the heat collecting part, and the opening end of the slot is suitable for being directed to a solar concentrator; one side of the heat exchanging part is connected with the other end of the heat collecting part, and the other side of the heat exchanging part is suitable for being connected with a thermoacoustic generator. By arranging the plurality of slots on the one end of the heat collecting part, the heat collecting part can be arranged at the focal point of the solar concentrator by adjusting the placement position and the direction of the heat collecting part, and the design of the plurality of slots can reduce the outward reflection of the sunlight, so that the sunlight can be captured and the light-heat conversion efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of solar thermal power generation system technology, and in particular to a high-temperature heat exchanger and thermoacoustic power generation system. Background Technology

[0002] A thermoacoustic generator is a novel thermoelectric conversion device consisting of a thermoacoustic engine and a linear motor, using inert gases such as helium as the working fluid. The external combustion nature of thermoacoustic generators allows for a wide range of heat source utilization methods, including fuel combustion, industrial waste heat, nuclear waste heat, and concentrated solar energy. Among these, solar energy, due to its safety, reliability, cleanliness, and renewability, has become one of the ideal energy sources for thermoacoustic generators.

[0003] As a key component for capturing light, absorbing and conducting heat energy, and even storing it, the structure of high-temperature heat exchangers has a significant impact on the power generation efficiency and energy utilization efficiency of solar thermal power generation systems.

[0004] Among them, the tube bundle type direct irradiation high temperature heat exchanger is a relatively mature solution for solar thermoacoustic generator absorbers. However, the existing direct irradiation high temperature heat exchanger has a low photothermal conversion efficiency and needs to be improved. Summary of the Invention

[0005] This invention provides a high-temperature heat exchanger and a thermoacoustic power generation system to solve the problem of low photothermal conversion efficiency of high-temperature heat exchangers in the prior art.

[0006] The present invention provides a high-temperature heat exchanger, comprising: a heat collection part and a heat exchange part, wherein a plurality of slots are distributed at one end of the heat collection part, and the opening end of the slots is adapted to face a solar concentrator; one side of the heat exchange part is connected to the other end of the heat collection part, and the other side of the heat exchange part is adapted to be connected to a thermoacoustic generator.

[0007] According to a high-temperature heat exchanger provided by the present invention, the end face of one end of the heat collection part is a concave arc surface, and the opening of the concave arc surface is adapted to face the solar concentrator; a plurality of slots are distributed on the concave arc surface; the heat exchange part is in contact with the end of the heat collection part away from the concave arc surface.

[0008] According to a high-temperature heat exchanger provided by the present invention, the straight-line distance from the bottom of each slot to the end of the heat exchange section is equal.

[0009] According to a high-temperature heat exchanger provided by the present invention, a plurality of the slots are uniformly arranged along the extension direction of the concave arc surface.

[0010] According to a high-temperature heat exchanger provided by the present invention, the heat collection part is provided with a receiving cavity, the heat exchange part is disposed in the receiving cavity, and the end of the heat exchange part is in contact with the inner top surface of the receiving cavity.

[0011] According to the present invention, a high-temperature heat exchanger is provided in which both the heat exchange part and the heat collection part are made of metal.

[0012] According to the present invention, a high-temperature heat exchanger is provided, wherein the heat exchange part is a copper heat exchanger and the heat collection part is a steel heat exchanger.

[0013] According to a high-temperature heat exchanger provided by the present invention, the outer surface of the heat exchange section and / or the heat collection section is provided with a heat-absorbing coating.

[0014] According to a high-temperature heat exchanger provided by the present invention, the heat exchange section includes a plurality of helium flow channels, one end of the plurality of helium flow channels is in contact with the heat collection section, and the other end of the plurality of helium flow channels is adapted to contact the thermoacoustic generator.

[0015] The present invention also provides a thermoacoustic power generation system, comprising: a thermoacoustic generator, a solar concentrator, and a high-temperature heat exchanger as described in any one of the above; the high-temperature heat exchanger is adapted to be disposed at the focal point of the solar concentrator, and the thermoacoustic generator is connected to the high-temperature heat exchanger.

[0016] The high-temperature heat exchanger and thermoacoustic power generation system provided by the present invention has multiple slots at one end of the heat collection part. By adjusting the placement and orientation of the heat collection part, the heat collection part can be placed at the focal point of the solar concentrator. The design of multiple slots can reduce the outward reflection of sunlight, thereby achieving the capture of sunlight and improving the photothermal conversion efficiency. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the thermoacoustic power generation system provided by the present invention;

[0019] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle;

[0020] Figure 3 This is one of the structural schematic diagrams of the high-temperature heat exchanger provided by the present invention;

[0021] Figure 4 This is the second schematic diagram of the high-temperature heat exchanger provided by the present invention.

[0022] Figure label:

[0023] 100: High-temperature heat exchanger; 110: Heat collection section; 111: Slot; 112: Concave arc surface; 113: Receiving cavity; 120: Heat exchange section; 121: Helium flow channel;

[0024] 210: Thermoacoustic generator; 220: Solar concentrator. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] A thermoacoustic generator is a novel thermoelectric conversion device consisting of a thermoacoustic engine and a linear motor, using inert gases such as helium as the working fluid. The external combustion nature of the thermoacoustic generator allows it to adapt to various heat sources, such as fuel combustion, industrial waste heat, nuclear waste heat, and concentrated solar energy. Among these, solar energy, due to its safety, reliability, cleanliness, and renewability, has become one of the ideal energy sources for thermoacoustic generators.

[0027] High-temperature heat exchangers are key components in solar thermal power generation systems, responsible for capturing light, absorbing and conducting heat, and even storing it. Their structure has a significant impact on the power generation efficiency and energy utilization efficiency of the solar thermal power generation system.

[0028] Existing high-temperature heat exchangers for solar thermoacoustic (and more broadly, Stirling structures) generators can be classified into three types according to their heat transfer methods: direct irradiation type, reflux type, and heat storage type.

[0029] Among them, the tube bundle direct irradiation high-temperature heat exchanger is widely used due to its advantages such as simple structure, easy processing and low cost, and has become a relatively mature solar thermoacoustic generator absorber solution.

[0030] The direct-irradiation high-temperature heat exchanger of the relevant technology has a low photothermal conversion efficiency. Increasing the heat absorption area and the direct radiation area will increase the convective and radiative heat loss. At the same time, the corresponding increase in the dead volume of the engine will affect the engine power.

[0031] Furthermore, a thicker layer of insulation material is usually wrapped around the outside of the high-temperature heat exchanger to reduce heat conduction loss. The large volume and complex structure of the insulation layer would contradict the advantage of the compact structure of the entire high-temperature heat exchanger and thermoacoustic generator.

[0032] In addition, due to the uneven heat distribution of the solar spot formed by the focusing device and the processing precision of the concentrator, the energy flux density distribution on the surface of the high-temperature heat exchanger may be uneven, and even "hot spots" may be generated in a small area, causing leakage of the circulating working fluid and damaging the system.

[0033] The aforementioned drawbacks result in existing solar thermoacoustic generators having large high-temperature heat exchangers, uneven energy flow density distribution, and significant light and heat loss.

[0034] To address the current shortcomings, this invention proposes a high-temperature heat exchanger 100 and a thermoacoustic power generation system.

[0035] The following is combined with Figures 1 to 4 The high-temperature heat exchanger 100 and thermoacoustic power generation system of the present invention are described.

[0036] like Figures 2 to 4 As shown, the high-temperature heat exchanger 100 of the present invention includes a heat collection section 110 and a heat exchange section 120.

[0037] The heat collection section 110 has a plurality of slots 111 distributed at one end, and the opening end of the slots 111 is adapted to face the solar concentrator 220; one side of the heat exchange section 120 is connected to the other end of the heat collection section 110, and the other side of the heat exchange section 120 is adapted to be connected to the thermoacoustic generator 210.

[0038] In related technologies, the end of the high-temperature heat exchanger 100 of the solar thermoacoustic generator 210 is usually flat. When sunlight shines on the end of the high-temperature heat exchanger 100, some of it is absorbed and some is reflected, resulting in a low absorption rate of sunlight.

[0039] The high-temperature heat exchanger 100 provided by the present invention has multiple slots 111 at one end of the heat collection part 110. By adjusting the placement and orientation of the heat collection part 110, the heat collection part 110 can be positioned at the focal point of the solar concentrator 220. The design of multiple slots 111 can reduce the outward reflection of sunlight, thereby capturing sunlight and improving the photothermal conversion efficiency.

[0040] Among them, the solar concentrator 220 is used to reflect and focus sunlight onto the focal plane to form a high-energy-flux-density solar focal spot that resembles an ellipse.

[0041] The thermoacoustic generator 210 is used to convert the solar energy absorbed by the high-temperature heat exchanger 100 into electricity.

[0042] The depth, diameter, and number of slots 111 at the end of the heat collection unit 110 can be set according to the specific application scenario. The diameters of the multiple slots 111 can be the same or different.

[0043] In some embodiments, such as Figure 3As shown, the central axes of the multiple slots 111 are parallel and they are distributed in a dot matrix pattern at the end of the heat collection section 110 to increase the number of slots 111 and further increase the solar energy capture efficiency.

[0044] Furthermore, the end face of one end of the heat collection section 110 is a concave arc surface 112, and the opening of the concave arc surface 112 is adapted to face the solar concentrator 220; a plurality of slots 111 are distributed on the concave arc surface 112; the heat exchange section 120 contacts the end of the heat collection section 110 away from the concave arc surface 112.

[0045] Among them, multiple slots 111 are used to capture solar energy.

[0046] By adjusting the placement of the heat collector 110, it can be positioned at the focal point of the solar concentrator 220, with the concave arc surface 112 of the heat collector 110 facing the solar concentrator 220, so that the concave arc surface 112 of the heat collector 110 coincides with the solar focal spot, thereby efficiently capturing solar energy through multiple slots 111.

[0047] Among them, the straight-line distance from the central axis of the concave arc surface 112 to the edge of the concave arc surface 112, and the end of the heat exchange section 120 increases sequentially.

[0048] In this embodiment, the concave arc surface 112 has a large structural heat capacity, which can resist temperature fluctuations in the heat exchange section 120, making the thermal performance stable during the heat absorption process, and the shorter heat transfer radius reduces heat loss during the heat transfer process.

[0049] The heat exchange section 120 is connected to the end of the heat collector section 110 that is away from the concave arc surface 112 to perform contact heat exchange between the heat exchange section 120 and the heat collector section 110.

[0050] The other side of the heat exchange section 120 is adapted to be in contact with the thermoacoustic generator 210 to perform contact heat exchange between the heat exchange section 120 and the thermoacoustic generator 210.

[0051] The concave arc surface 112 can be a part of a sphere, and the specific size and concave depth can be selected according to the specific application scenario.

[0052] The high-temperature heat exchanger 100 provided by the present invention, on the one hand, increases the area for collecting sunlight by setting the end face of the heat collection part 110 away from the heat exchange part 120 as an inwardly concave arc surface 112, which is relative to a plane, thereby further improving the absorption efficiency of sunlight.

[0053] Understandably, when high-energy-flux-density sunlight shines on the concave arc surface 112, a portion directly radiates to the outer surface of the concave arc surface 112, heating the outer surface of the heat exchange section 120 through direct radiation heat exchange. The heat energy is then conducted to the inner surface of the high-temperature heat exchanger 100 and absorbed by the high-temperature, high-pressure circulating working fluid. Another portion of the sunlight, after multiple reflections within the slotted structure 111, is conducted to the inner surface of the high-temperature heat exchanger 100, where it convects with the working fluid. The slotted structure 111 reduces outward reflection of sunlight, improves solar energy absorption efficiency, and reduces light and heat loss.

[0054] Furthermore, such as Figure 2 As shown, the straight-line distance from the bottom of each slot 111 to the end of the heat exchange section 120 is equal.

[0055] It should be noted that since the straight-line distance from the bottom of each slot 111 to the end of the heat exchange section 120 is equal, the depth of the slot 111 located near the center of the concave arc surface 112 is less than the depth of the slot 111 located near the edge of the concave arc surface 112.

[0056] It is understandable that the depth of the slot 111 is inversely proportional to the absorption rate of sunlight. The greater the depth of the slot 111, the less light is reflected outward, and the greater the absorption rate of sunlight. The smaller the depth of the slot 111, the more light is reflected outward, and the smaller the absorption rate of sunlight.

[0057] The sunlight is concentrated in the slot 111 located near the center of the concave arc surface 112, but the depth of the slot 111 is small. The sunlight is dispersed in the slot 111 near the edge of the concave arc surface 112, and the depth of the slot 111 is large. In this way, the amount of sunlight absorbed by multiple slots 111 on the concave arc surface 112 can be consistent, and the high energy flux density can be evenly distributed at the other end of the heat collection part 110, thereby achieving the uniformity of the internal temperature of the heat exchange part 120.

[0058] Furthermore, multiple slots 111 are evenly arranged along the extension direction of the concave arc surface 112, and the multiple slots 111 are distributed in a dot matrix pattern to ensure that the front of the concave arc surface 112 captures solar energy.

[0059] In this embodiment, the dot matrix slot cavity structure 111 can reduce outward reflection of light, enhance the capture of light, improve the photothermal conversion efficiency, and at the same time improve the uniformity of heat flux density of the high-temperature heat exchanger 100.

[0060] In some embodiments, the slot 111 is a circular hole to achieve uniform light refraction.

[0061] In some embodiments, the heat collection section 110 is provided with a receiving cavity 113, and the heat exchange section 120 is provided in the receiving cavity 113. The end of the heat exchange section 120 contacts the inner top surface of the receiving cavity 113 to increase the integration of the high-temperature heat exchanger 100.

[0062] The heat exchange section 120 has a flat end and the inner top surface of the receiving cavity 113. The straight-line distance from the bottom of each slot 111 to the inner top surface of the receiving cavity 113 is equal, thereby achieving uniform heat flux density at the end of the heat exchange section 120.

[0063] In some embodiments, a clearance cavity is provided at one end of the heat exchange section 120 away from the heat collection section 110. The inner wall of the clearance cavity is adapted to the protrusion of the thermoacoustic generator 210, and the heat exchange section 120 and the thermoacoustic generator 210 are contacted and heat exchanged through surface-to-surface contact.

[0064] In some embodiments, both the heat exchange section 120 and the heat collection section 110 are made of metal, such as copper, iron, stainless steel, etc. Based on the high thermal conductivity of metal materials, the photothermal conversion efficiency of the high-temperature heat exchanger 100 is further improved.

[0065] In some embodiments, the heat exchange section 120 is a copper heat exchanger and the heat collection section 110 is a steel heat exchanger.

[0066] Among them, the heat exchange section 120 is made of copper, and the good thermal conductivity of copper is conducive to improving the photothermal conversion efficiency of the high-temperature heat exchanger 100.

[0067] In some embodiments, the heat exchange section 120 and the heat collector section 110 are made of the same material, for example, the heat exchange section 120 and the heat collector section 110 are made of stainless steel, and 3D printing technology can be applied to reduce the processing difficulty and cost.

[0068] In some embodiments, the outer surface of the heat exchange section 120 and / or the heat collection section 110 is provided with a heat-absorbing coating to reduce radiative heat loss, enhance the heat transfer process inside the high-temperature heat exchanger 100, and improve the heat conversion efficiency.

[0069] The thermal coating includes at least the following two configuration methods.

[0070] Firstly, the heat collection part 110 and the heat exchange part 120 are separate assembled structures, and the outer surface of the heat exchange part 120 is provided with a thermal coating.

[0071] Secondly, the heat collection part 110 and the heat exchange part 120 are an integral structure, that is, the high temperature heat exchanger 100 is made by 3D printing technology, and the outer surface of the high temperature heat exchanger 100 is provided with a thermal coating, that is, the outer surface of the heat collection part 110 and the heat exchange part 120 exposed to the outside is provided with a thermal coating.

[0072] Furthermore, the heat exchange section 120 includes a plurality of helium flow channels 121, one end of which is in contact with the heat collection section 110, and the other end of which is adapted to be in contact with the thermoacoustic generator 210.

[0073] The multiple helium flow channels 121 are integrated structures, and the multiple helium flow channels 121 are arranged in parallel to increase the number of helium flow channels 121, increase the heat absorption area of ​​the working fluid, and ensure the compactness of the structure.

[0074] Among them, the helium flow channel 121 can reduce the processing difficulty and cost through 3D printing technology.

[0075] In some embodiments, a plurality of helium flow channels 121 extend axially along the heat exchange section 120, thereby enhancing the pressure resistance of the high-temperature heat exchanger 100.

[0076] When the high-temperature heat exchanger 100 provided by the present invention is working, sunlight is incident on the solar concentrator 220 which is shaped like a parabolic rotating surface. The sunlight reflected by the mirror is focused onto the focal plane of the parabolic surface and forms a solar focal spot with high energy flux density similar to an ellipse.

[0077] By adjusting the position of the high-temperature heat exchanger 100, the concave arc surface 112 of the heat collector 110 is aligned with the focal spot. A portion of the high-energy-flux-density sunlight directly radiates onto the outer surface of the concave arc surface 112, heating the outer end surface of the heat exchanger 120 through direct radiation heat exchange. The heat energy is then conducted to the inner surface of the heat exchanger 120 and absorbed by the high-temperature, high-pressure circulating working fluid. Another portion of the sunlight, after multiple reflections within the lattice-patterned slotted cavity structure on the outer surface of the concave arc surface 112, is conducted to the inner surface of the heat exchanger 120, where it convects with the working fluid. The lattice-patterned slotted cavity structure reduces outward reflection of sunlight, improving solar energy absorption efficiency and reducing photothermal loss.

[0078] The heat exchange between the solar-converted heat and the working fluid does not occur on the outer surface of the heat exchange section 120 where the energy flow density is strongest, but rather is conducted through a shorter heat transfer radius to the inner surface of the heat exchange section 120 where it is evenly distributed and absorbed.

[0079] The working fluid of the thermoacoustic generator 210 absorbs energy from sunlight to form a high-temperature and high-pressure gas that drives the piston to do work. Part of the acoustic power generated is transferred to the main piston and then output as electrical energy through a linear motor, while the other part returns to the engine side to complete the next thermoacoustic cycle.

[0080] The high-temperature heat exchanger 100 provided by the present invention sets the end face of one end of the heat collection part 110 as an inwardly concave arc surface 112, and the inwardly concave arc surface 112 is distributed with multiple slots 111, which can effectively capture solar energy and has a series of advantages such as low light and heat loss, uniform and stable heat flow distribution on the wall, simple structure, and strong pressure resistance. It can improve energy conversion efficiency and reduce processing difficulty and manufacturing cost.

[0081] like Figure 1 As shown, the present invention also provides a thermoacoustic power generation system, including a thermoacoustic generator 210, a solar concentrator 220 and a high-temperature heat exchanger 100 of any of the above.

[0082] The thermoacoustic generator 210 is connected in contact with the high-temperature heat exchanger 100, which is placed at the focal point of the solar concentrator 220.

[0083] The thermoacoustic power generation system provided by the present invention sets the end face of one end of the heat collection part 110 as a concave arc surface 112, and the concave arc surface 112 is distributed with multiple slots 111, which can effectively capture solar energy. It has a series of advantages such as low light and heat loss, uniform and stable heat flow distribution on the wall, simple structure, and strong pressure resistance. It can improve energy conversion efficiency and reduce processing difficulty and manufacturing cost.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-temperature heat exchanger, characterized in that, include: The heat collection section has multiple slots distributed at one end, and the opening end of the slots is adapted to face the solar concentrator. The heat exchange section is connected on one side to the other end of the heat collection section, and on the other side is adapted to be connected to a thermoacoustic generator. The end face of one end of the heat collection part is a concave arc surface, and the opening of the concave arc surface is adapted to face the solar concentrator. Multiple slots are distributed on the concave arc surface; The heat exchange section contacts the end of the heat collection section that is away from the concave arc surface; The straight-line distance from the bottom of each slot to the end of the heat exchange section is equal; The depth of the slot located near the center of the concave arc surface is less than the depth of the slot located near the edge of the concave arc surface; The plurality of slots are evenly arranged along the extension direction of the concave arc surface.

2. The high-temperature heat exchanger according to claim 1, characterized in that, The heat collection part is provided with a receiving cavity, the heat exchange part is disposed in the receiving cavity, and the end of the heat exchange part is in contact with the inner top surface of the receiving cavity.

3. The high-temperature heat exchanger according to any one of claims 1 to 2, characterized in that, Both the heat exchange section and the heat collection section are made of metal.

4. The high-temperature heat exchanger according to claim 3, characterized in that, The heat exchange section is a copper heat exchanger, and the heat collection section is a steel heat exchanger.

5. The high-temperature heat exchanger according to any one of claims 1 to 2, characterized in that, The outer surface of the heat exchange section and / or the heat collection section is provided with a heat-absorbing coating.

6. The high-temperature heat exchanger according to any one of claims 1 to 2, characterized in that, The heat exchange section includes multiple helium flow channels, one end of which is in contact with the heat collection section, and the other end of which is adapted to be in contact with the thermoacoustic generator.

7. A thermoacoustic power generation system, characterized in that, Includes thermoacoustic generators, solar concentrators, and high-temperature heat exchangers as described in any one of claims 1 to 6; The high-temperature heat exchanger is adapted to be installed at the focal point of the solar concentrator, and the thermoacoustic generator is connected to the high-temperature heat exchanger.

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