A tower type solar power cyclone heat absorber

Abstract

A tower type solar energy cyclone heat absorber contains a metal hot plate, a metal bath cavity, a spiral coil pipe, an import shunt main pipe, an export collection main pipe and the like. Sunlight is precisely focused on the outer plate of the metal hot plate, the metal hot plate is heated to make the internal liquid metal gasify and then condense on the inner plate, the heat is unidirectionally transferred to the metal bath cavity, the heat absorption medium filled in the metal bath cavity is heated and melted to uniformly transfer the high heat flux density heat to the spiral coil pipe, and the heat is taken away by the heat exchange medium in the spiral coil pipe. The heat exchange medium flows into each coil pipe branch pipe through the import shunt main pipe, is gathered after passing through the export collection pipe and then flows out. The metal bath cavity adopts the metal bath indirect heat transfer, has the characteristics of high heat conduction coefficient and the uniform temperature function, can realize high efficient heat transfer, and can uniformly heat the heat flux density, reduce the thermal stress, avoid the hazards such as pipe explosion and the like. The heat exchange medium can be heated to the supercritical state, and the power generation efficiency is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature solar thermal utilization technology, specifically relating to a tower-type solar vortex absorber. Background Technology

[0002] With rapid economic development, the demand for energy is constantly increasing. Currently, traditional fossil fuels remain the main driver of global economic growth, but the carbon dioxide and other pollutants released after their combustion severely pollute the environment, exacerbating the energy crisis and global warming. Improving the energy structure and vigorously developing renewable and clean energy are crucial, and the inexhaustible solar energy has received widespread attention. Compared to photovoltaic power generation, concentrated solar power (CSP) technology is cleaner in its raw material manufacturing process and can be combined with energy storage systems for 24-hour power generation. However, due to its lower power generation efficiency and higher cost, improving CSP efficiency and reducing costs has become a development challenge. In CSP systems, tower solar thermal power systems, with their high concentration ratio, can achieve higher operating temperatures, thus improving overall power generation efficiency and are becoming more popular in future development trends. As the core heat-absorbing component of tower solar systems, the receiver reflects and concentrates sunlight directly onto the absorber plate. Under high heat flux density loads, it is prone to uneven heating, leading to dangers such as pipe bursts and leaks. Ensuring the stable and efficient operation of the receiver has become a key technical issue for current tower solar thermal power systems. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a tower-type solar vortex absorber that features unidirectional heat transfer, reduced heat dissipation, high photothermal conversion efficiency, uniform temperature and heat distribution, low thermal stress, heat storage, and high pressure resistance. It can heat the heat exchange medium to a supercritical or ultra-supercritical state, greatly improving operating parameters and power generation efficiency.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A tower-type solar vortex absorber, characterized in that it comprises: a metal hot plate, a metal bath cavity, a spiral coil, an inlet diverter main, an outlet collector main, and a central cylinder; several metal hot plates are arranged around the metal bath cavity, each forming several independent chambers, each chamber filled with liquid metal, the liquid metal transferring heat absorbed by the metal hot plates to the metal bath cavity through vaporization and condensation, the metal bath cavity being filled with a heat-absorbing medium; the spiral coil is wound circumferentially around the central cylinder, the spiral coil is immersed in the heat-absorbing medium, the outer wall of the spiral coil and the wetting surface of the heat-absorbing medium serve as the heat transfer surface, the spiral coil flows into the heat exchange medium through the inlet diverter main and flows out of the heat exchange medium through the outlet collector main.

[0006] To optimize the above technical solution, the specific measures also include:

[0007] Furthermore, the metal hot plate includes a heat-absorbing plate, a hot plate upper cover, a hot plate lower cover, an inner wall surface, a side sealing plate, and a partition. The heat-absorbing plate, the hot plate upper cover, the hot plate lower cover, the inner wall surface, and the side sealing plate are spliced ​​together to form a sealed cavity. Several inclined partitions are evenly distributed in the sealed cavity and divide the sealed cavity into several independent chambers. The heat-absorbing plate is used to absorb the heat of sunlight, and the inner wall surface forms the heat-absorbing wall surface of the metal bath cavity.

[0008] Furthermore, the metal bath chamber is formed by splicing an inner wall surface, an upper cover plate, a lower cover plate, and a central cylinder. The upper cover plate and the lower cover plate are arranged opposite to each other, and both the upper cover plate and the lower cover plate have holes corresponding to the spiral coil.

[0009] Furthermore, the spiral coil is welded and fixed to the upper cover plate and the lower cover plate of the bath chamber, and the spiral coil is not in direct contact with the central cylinder.

[0010] Furthermore, the spiral coil is composed of several coil branch pipes arranged together. The spiral coil is installed on the central cylinder by a limiting pad. The bottom of the limiting pad is fixed to the central cylinder along the axial direction. The surface of the limiting pad is provided with several arc-shaped grooves corresponding to the several coil branch pipes. The coil branch pipes are movably installed in the arc-shaped grooves.

[0011] Furthermore, the number of spiral coils is not just one; several spiral coils are stacked and wound circumferentially around the central cylinder. Each group of spiral coils corresponds to a limiting pad, and the limiting pads are connected to each other by flat pads.

[0012] Furthermore, the metal hot plate, metal bath cavity, and spiral coil are made of P91 steel or P92 steel.

[0013] Furthermore, the heat-absorbing medium is a pure metal or a mixture of metals.

[0014] Furthermore, the heat exchange medium is water, purified and pressurized air, or purified and pressurized carbon dioxide.

[0015] Furthermore, the metal hot plate is designed using the following formula:

[0016]

[0017] In the formula, ΔP v μ is the pressure loss of metal vapor inside the hot plate. v ρ is the dynamic viscosity of the metal vapor inside the hot metal plate. v Let ρ be the density of the metal vapor inside the high-temperature hot plate, θ be the angle between the partition and the horizontal plane, L be the vertical distance between the two partitions, and d be the distance between the heat absorber plate and the inner wall surface. f is the Fanning drag coefficient, d e Let ξ be the equivalent diameter and ξ be the local drag coefficient.

[0018] The beneficial effects of this invention are:

[0019] 1) The indirect and efficient heat transfer method avoids direct sunlight and solves problems such as thermal fatigue and thermal ratchet caused by thermal stress due to direct heat transfer, thus greatly extending the service life of the heat absorber.

[0020] 2) The use of a metal hot plate (high temperature hot plate) to absorb and transfer heat realizes unidirectional heat transfer, solves the problem of heat loss during the heat transfer process, and improves the photothermal conversion efficiency of the heat absorber; the structure of the partition and independent cavity is innovatively proposed, and a specific design scheme for the metal hot plate is proposed, which fully considers the condensation and evaporation process of liquid metal and the economic safety of the overall structure. The Fanning formula is used to calculate and limit the parameters of the metal hot plate.

[0021] 3) The heat transfer medium with high thermal conductivity and the high specific surface area of ​​the spiral coil can rapidly transfer heat to the heat exchange medium; and the flowing heat absorption medium can evenly transfer heat to the spiral coil, giving the metal bath excellent temperature uniformity and the ability to withstand high heat flux density loads. Unlike the mode formed by splicing multiple independent tube banks / heat exchange channels, the integrated heat absorption medium makes the heat distribution more uniform;

[0022] 4) The parallel arrangement of multi-tube and multi-layer spiral coils greatly improves the heat exchange medium flux and heat transfer capacity, which can effectively prevent the danger of tube rupture caused by local overheating due to rapid temperature rise; the low thermal stress technology is adopted, the spiral coils are welded to the upper and lower cover plates, but not to the central cylinder, so that the spiral coils can freely expand and contract when heated, reducing thermal stress.

[0023] 5) A limiting pad and a flat pad were designed to match the installation of the spiral coil, which allows the spiral coil to freely expand and contract in high-temperature environments, thereby significantly reducing thermal stress and improving the safety, reliability and service life of the equipment. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the external shape of the tower-type solar vortex absorber of the present invention.

[0025] Figure 2 This is a top view of the tower-type solar vortex absorber of the present invention.

[0026] Figure 3 This is a partially exploded schematic diagram of the metal hot plate of the present invention.

[0027] Figure 4This is a schematic diagram of the liquid metal filling in the metal hot plate of the present invention.

[0028] Figure 5a This is a schematic diagram of the coil branch pipe interface of the present invention.

[0029] Figure 5b This is a schematic diagram of the inlet diverter pipe and the outlet manifold pipe of the present invention.

[0030] Figure 6 This is a partially exploded schematic diagram of the metal bath chamber of the present invention.

[0031] Figure 7a This is a schematic diagram of the limiting pad and the protective pad of the present invention.

[0032] Figure 7b This is a schematic diagram of the installation of each coil branch pipe in the limiting pad strip of the present invention.

[0033] Figure 8 This is a schematic diagram of the working process of the tower-type solar vortex absorber of the present invention.

[0034] Figure 9 This is a schematic diagram illustrating the change in sodium vapor flow loss within the independent chamber of the metal hot plate of the present invention as a function of the partition tilt angle.

[0035] The attached diagram is labeled as follows: 1. Metal hot plate; 1.1. Absorbing plate; 1.2. Hot plate upper cover; 1.3. Hot plate lower cover; 1.4. Inner wall surface; 1.5. Side sealing plate; 1.6. Partition; 2. Metal bath chamber; 2.1. Bath chamber upper cover; 2.2. Bath chamber lower cover; 3. Spiral coil; 3.1. Coil branch pipe; 4. Inlet branch main pipe; 5. Outlet manifold main pipe; 6. Central cylinder; 6.1. Limiting gasket; 6.2. Flat gasket; 6.3. Arc-shaped groove; 7. Liquid metal; 8. Absorbing medium. Detailed Implementation

[0036] The invention will now be described in further detail with reference to the accompanying drawings.

[0037] Example 1

[0038] This embodiment proposes a method such as Figure 1 and Figure 2The tower-type solar vortex absorber shown comprises a metal hot plate 1, a metal bath chamber 2, a spiral coil 3, an inlet branch pipe 4, an outlet collector pipe 5, and a central cylinder 6. The metal hot plates 1 are all independent, with multiple plates assembled in a circle. Sunlight is reflected and concentrated onto the absorber plate 1.1 of the metal hot plate 1 by a heliostat field. The metal hot plate 1 absorbs the heat from the sunlight and transfers it unidirectionally to the metal bath chamber 2, causing the heat-absorbing medium 8 inside the metal bath chamber 2 to heat up and melt. The heat-absorbing medium 8 then transfers the heat to the spiral coil 3. The spiral coil 3 is immersed in the heat-absorbing medium 8, with its outer wall and the wetting surface of the heat-absorbing medium 8 serving as the heat transfer surface. The heat exchange medium flows into each spiral coil 3 through the inlet branch pipe 4 and flows out through the outlet collector pipe 5. This absorber uses an indirect heat transfer method, effectively solving problems such as thermal stress and thermal fatigue caused by the large temperature difference resulting from direct heat transfer.

[0039] like Figure 3 and Figure 4 As shown, the metal hot plate 1 is polygonal in shape and is composed of an absorber plate 1.1, an upper cover plate 1.2, a lower cover plate 1.3, an inner wall surface 1.4, a side sealing plate 1.5, and a partition plate 1.6. The partition plate 1.6 divides the interior of the metal hot plate 1 into multiple independent chambers. Each chamber is evacuated and heated, and liquid metal is filled into it to maintain a high temperature environment. The liquid metal can be pure metals or metal mixtures such as potassium, sodium, and lithium, but not limited to potassium, sodium, and lithium. Sunlight is reflected onto the absorber plate 1.1, and after absorbing heat, the temperature rises, causing the liquid metal inside the chamber to vaporize and then condense on the inner wall surface 1.4. The liquid metal 7 in each chamber circulates through evaporation, condensation, and gravity recirculation, transferring heat unidirectionally and efficiently to the inner wall surface 1.4. The metal hot plate 1 used in the absorber of this invention can transfer heat unidirectionally and reduce heat loss during the heat transfer process, effectively improving the photothermal conversion efficiency of the absorber.

[0040] like Figure 6 As shown, the inner wall surfaces 1.1 of multiple metal hot plates 1 constitute an integral heat-absorbing wall surface of a metal bath cavity 2. The heat-absorbing medium 8 can flow freely inside the metal bath cavity 2, resulting in better stability and heat uniformity during operation, and largely avoiding the problem of uneven heating under high heat flux density loads.

[0041] like Figure 6As shown, the metal bath chamber 2 is polygonal in shape and is composed of an inner wall surface 1.4, an upper cover plate 2.1, a lower cover plate 2.2, and a central cylinder 6. The metal bath chamber 2 is filled with a heat-absorbing medium 8, which can be metal tin, aluminum, etc., but is not limited to tin, aluminum, other metals, or metal mixtures. When the heat absorber is working, the metal melts, and the spiral coil 3 is immersed in the liquid metal. The surface between the outer wall of the tube and the immersion surface of the liquid metal serves as the heat transfer surface, employing a "metal bath" heat transfer method, which has the function of uniform temperature. On the one hand, metal has a high thermal conductivity, which can stably enhance the heat exchange effect of the spiral coil 3; on the other hand, the flowing liquid metal can evenly transfer heat to the spiral coil 3, avoiding the damage caused by concentrated sunlight directly reflecting onto the spiral coil 3.

[0042] like Figure 5a , Figure 5b , Figure 7a and Figure 7b As shown, this embodiment designs a new fixing structure for the installation and support of the spiral coil 3. To achieve efficient thermal stress management, low thermal stress technology is adopted. Both the upper cover plate 2.1 and the lower cover plate 2.2 of the bath chamber are provided with holes matching the spiral coil 3. The spiral coil 3 is fixed to the upper cover plate 2.1 and the lower cover plate 2.2 of the bath chamber by welding, while avoiding welding to the central cylinder 6. Instead, limiting pads 6.1 and flat pads 6.2 are used to restrict the spiral coil 3 to a relatively fixed position. The spiral coil 3 is composed of several coil branch pipes 3.1 arranged in a row. The bottom of the limiting pads 6.1 is fixed axially to the central cylinder 6. The surface of the limiting pads 6.1 has several arc-shaped grooves 6.3 corresponding to the coil branch pipes 3.1. The coil branch pipes 3.1 are movably installed in the arc-shaped grooves 6.3. This design allows the spiral coil 3 to freely expand and contract in high-temperature environments, thereby significantly reducing thermal stress and improving the safety, reliability, and service life of the equipment.

[0043] like Figure 5a , Figure 5b , Figure 6 , Figure 7a and Figure 7b As shown, the heat exchange medium under supercritical pressure enters each spiral coil 3 through the inlet branch pipe 4, and the generated supercritical heat exchange medium flows out after being collected through the outlet manifold 5. The overall piping sealing and piping materials of the system have very strict standards. The metal hot plate 1, metal bath chamber 2, spiral coil 3, inlet branch pipe 4, and outlet manifold 5 all use existing high-temperature pressure-resistant materials such as P91 and P92.

[0044] like Figure 2 , Figure 6 , Figure 7a , Figure 7b and Figure 8As shown, several coil branch pipe interfaces (W1-Wn) are opened on the upper cover plate 2.1 and lower cover plate 2.2 of the bath chamber. Each interface connects to a separate heat exchange medium flow channel, and each coil branch pipe 3.1 constitutes a heat exchange medium flow channel return. The specific number of spiral coils can be increased or decreased according to actual needs. The spiral coil 3 is made of a material with high thermal conductivity and high temperature and pressure resistance (including but not limited to P91, P92, etc.) to ensure efficient heat conduction. At the same time, the spiral shape of the spiral coil 3 can enhance the heat exchange effect and improve the heat exchange efficiency between the heat-absorbing fluid and the liquid metal in the metal bath chamber. The heat exchange medium flow channel return is restricted in the limiting strip 6.1 and separated from the heat exchange medium flow channel return of the previous layer by the flat strip 6.2, which enhances the stability of the spiral coil 3. The flat strip 6.2 of the upper layer is directly fixed to the limiting strip 6.1 of the lower layer, and the limiting strip 6.1 of the bottom layer is directly fixed to the central cylinder 6. The limiting pad 6.1 and the flat pad 6.2 are made of P91 or P92 high temperature resistant steel.

[0045] After entering each spiral coil through the inlet manifold 4, the heat exchange medium flows in a swirling pattern. The large specific surface area of ​​the spiral coil 3 and the unique swirling phenomenon formed within it enhance the heat transfer capacity. Furthermore, the spiral structure allows for long-distance heat transfer within the coil 3, improving the power generation efficiency of the heat exchange medium under supercritical conditions. After absorbing heat, the heat exchange medium flows out through the outlet manifold 5. A portion directly enters the expander to expand and drive the generator, while the other portion is used in conjunction with an energy storage system to store the energy.

[0046] Example 2

[0047] The tower-type solar vortex absorber proposed in Example 1 innovatively incorporates a partition and independent cavity structure in the metal hot plate 1. However, the specific design scheme of the metal hot plate 1 is not limited to this; the condensation and evaporation process of the liquid metal 7 and the economic safety of the overall structure must also be fully considered. Therefore, this example proposes a design method for the metal hot plate, and calculates and limits the parameters of the metal hot plate 1.

[0048] Compared to traditional heat pipes, in high-temperature metal hot plates, steam flows along the thickness direction, resulting in a shorter flow path, all within an adiabatic section, with minimal impact from the wall boundary on the steam volume. Depending on the flow pattern, laminar or turbulent flow formulas can be selected.

[0049] The Hagen-Poiseuille formula is only applicable to laminar flow:

[0050]

[0051] In the formula, ΔP is the pressure drop in Pa; l is the pipe length in m; and μ is the dynamic viscosity in N·s / m. 2m is the mass flow rate, kg / s; A is the pipe cross-sectional area, mm². 2 R is the pipe radius, mm; ρ is the fluid density, kg / m³ 3 .

[0052] Fanning's formula applies to both laminar and turbulent flow:

[0053]

[0054] In the formula, ξ is the local drag coefficient; d e f is the equivalent diameter, in meters (m); u is the fluid velocity, in meters per second (m / s); F is the Fanning drag coefficient, which is related to the Reynolds number Re. When Re < 2100, f = 16 / Re; when 2100 < Re < 10... 5 At that time, f = 0.0791 / Re 0.25 .

[0055] The steam velocity inside the steam chamber is calculated as follows:

[0056]

[0057] In the formula, m v The mass flow rate of steam; kg / s; ρ v ρ is the steam density, kg / m³; s is the heat transfer perimeter of a single chamber, m.

[0058] The steam flow loss within the steam chamber is calculated using the Fanning formula, and the steam pressure drop is:

[0059]

[0060] In the above formula Each quantity is a fixed value under specific experimental conditions, and therefore can be regarded as a constant factor, denoted as K. Thus, the above equation becomes:

[0061]

[0062] In the formula, ΔP v μ is the pressure loss of metal vapor inside the hot plate. v ρ is the dynamic viscosity of the metal vapor inside the hot metal plate. v θ is the density of the metal vapor inside the high-temperature hot plate, θ is the tilt angle (i.e., the angle between the partition and the horizontal plane), L is the vertical distance between the two partitions, and d is the width of the metal hot plate (i.e., the distance between the heat-absorbing plate and the inner wall).

[0063] Figure 9This illustrates the variation of sodium vapor flow loss within the steam chamber with the tilt angle of the baffle. As the tilt angle increases, the pressure loss of the metal vapor flow decreases. Theoretically, the tilt angle of the baffle can be further increased, but excessively large angles significantly increase the requirements for manufacturing processes, negatively impact overall strength, and increase the amount of sodium required, thus raising manufacturing costs and complexity. Therefore, the design of the metal hot plate should incorporate calculated data analysis to ensure both the condensation and evaporation process of the liquid metal and the safety and economy of the overall structure.

[0064] It should be noted that the terms such as "upper", "lower", "left", "right", "front", and "back" used in the invention are only for clarity of description and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0065] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A tower-type solar vortex absorber, characterized in that, include: Metal hot plate (1), metal bath cavity (2), spiral coil (3), inlet diversion main pipe (4), outlet collection main pipe (5) and central cylinder (6); several metal hot plates (1) are arranged around the metal bath cavity (2), and several independent chambers are formed inside the metal hot plate (1). Each chamber is filled with liquid metal (7). The liquid metal (7) transfers the heat absorbed by the metal hot plate (1) to the metal bath cavity (2) through the process of vaporization and condensation. The metal bath cavity (2) is filled with heat-absorbing medium (8); the spiral coil (3) is wound around the central cylinder (6) in the circumferential direction. The spiral coil (3) is immersed in the heat-absorbing medium (8). The outer wall of the spiral coil (3) and the wetting surface of the heat-absorbing medium (8) serve as the heat transfer surface. The spiral coil (3) flows into the heat exchange medium through the inlet diversion main pipe (4) and flows out of the heat exchange medium through the outlet collection main pipe (5); The metal hot plate (1) includes a heat-absorbing plate (1.1), a hot plate upper cover plate (1.2), a hot plate lower cover plate (1.3), an inner wall surface (1.4), a side sealing plate (1.5), and a partition plate (1.6); the heat-absorbing plate (1.1), the hot plate upper cover plate (1.2), the hot plate lower cover plate (1.3), the inner wall surface (1.4), and the side sealing plate (1.5) are spliced ​​together to form a sealed cavity, and several inclined partition plates (1.6) are evenly distributed in the sealed cavity and divide the sealed cavity into several independent chambers. The heat-absorbing plate (1.1) is used to absorb the heat of sunlight, and the inner wall surface (1.4) forms the heat-absorbing wall surface of the metal bath cavity (2); The metal bath chamber (2) is formed by splicing an inner wall surface (1.4), a bath chamber upper cover plate (2.1), a bath chamber lower cover plate (2.2) and a central cylinder (6). The bath chamber upper cover plate (2.1) and the bath chamber lower cover plate (2.2) are arranged opposite to each other. Both the bath chamber upper cover plate (2.1) and the bath chamber lower cover plate (2.2) are provided with holes corresponding to the spiral coil (3). The metal hot plate (1) is designed using the following formula: In the formula, This refers to the pressure loss of metal vapor inside the hot plate. The dynamic viscosity of the metal vapor within the hot metal plate. The density of the metal vapor inside the high-temperature hot plate. The angle between the partition and the horizontal plane. It is the vertical distance between the two partitions. It is the distance between the heat absorber and the inner wall surface. , Fanning drag coefficient, Equivalent diameter This is the local drag coefficient.

2. The tower-type solar vortex absorber as described in claim 1, characterized in that: The spiral coil (3) is welded and fixed to the upper cover plate (2.1) and the lower cover plate (2.2) of the bath chamber, and the spiral coil (3) is not in direct contact with the central cylinder (6).

3. A tower-type solar vortex absorber as described in claim 1, characterized in that: The spiral coil (3) is composed of several coil branch pipes (3.1) arranged together. The spiral coil (3) is installed on the central cylinder (6) by a limiting pad (6.1). The bottom of the limiting pad (6.1) is fixed on the central cylinder (6) along the axial direction. The surface of the limiting pad (6.1) is provided with several arc-shaped grooves (6.3) corresponding to the several coil branch pipes (3.1). The coil branch pipes (3.1) are movably installed in the arc-shaped grooves (6.3).

4. A tower-type solar vortex absorber as described in claim 3, characterized in that: The number of spiral coils (3) is not one. Several spiral coils (3) are stacked and wound around the central cylinder (6) in the circumferential direction. Each group of spiral coils (3) corresponds to a limiting pad (6.1). The limiting pads (6.1) are connected to each other by flat pads (6.2).

5. A tower-type solar vortex absorber as described in claim 1, characterized in that: The metal hot plate (1), metal bath cavity (2) and spiral coil (3) are made of P91 steel or P92 steel.

6. A tower-type solar vortex absorber as described in claim 1, characterized in that: The heat-absorbing medium (8) is a pure metal or a mixture of metals.

7. A tower-type solar vortex absorber as described in claim 1, characterized in that: The heat exchange medium is water, purified and pressurized air, or purified and pressurized carbon dioxide.

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