A tower solar supercritical air heat absorber

Abstract

The application discloses a tower type solar supercritical air heat absorber, which comprises a heat absorbing plate, a cylinder jacket, inlet and outlet pipelines, a phase change working medium and a heat exchange medium and the like. Sunlight is reflected on the heat absorbing plate by a heliostat field, and the heat absorbing plate is externally covered with a heat absorbing coating to strengthen the heat absorbing capacity of the surface. The heat absorbing plate absorbs the heat of the sunlight and transmits the heat to the phase change working medium located in the heat absorbing plate, the phase change working medium releases heat by phase change, and the heat is transmitted to the heat exchange medium located in the outer wall of the cylinder jacket; the inlet and outlet pipelines comprise inlet pipelines and outlet pipelines, the heat exchange medium flows into the cylinder jacket through the inlet pipelines and flows out of the cylinder jacket through the outlet pipelines. The heat absorber structure can heat compressed air to a supercritical state, and greatly improves the power generation efficiency.

Description

Technical Field

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

[0002] Solar power generation is ushering in an unprecedented and significant development opportunity. Compared to photovoltaic power generation, concentrated solar power (CSP) has unique advantages such as continuous, stable, and adjustable output and low carbon emissions. However, the high cost of CSP is a major reason why it has not been commercially applied. Among the various forms of CSP utilization, tower solar power systems have broader application prospects due to their high photothermal conversion efficiency and high concentration ratio. As the core heat-absorbing component of tower solar power systems, the receiver is particularly vulnerable to problems such as thermal fatigue and thermal ratcheting caused by uneven heating of the heat-absorbing surface, which can seriously affect the stability and heat absorption efficiency of the receiver. Ensuring that the receiver can maximize photothermal conversion efficiency while maintaining stable operation has become a key technical challenge for the advancement of tower solar power systems. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a tower-type supercritical air solar receiver. The device has a simple structure, is easy to assemble and disassemble, and possesses high heat exchange efficiency and photothermal conversion rate. It exhibits good resistance to thermal loads and thermal shocks from non-uniform, unsteady, and high heat flux densities, and effectively addresses problems such as thermal fatigue and thermal ratcheting caused by uneven local heating in current flat-plate receivers.

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

[0005] A tower-type supercritical air solar absorber, characterized in that it comprises: an absorber plate, a cylindrical jacket, inlet and outlet pipes, a phase change working fluid, and a heat exchange medium; the absorber plate absorbs heat from sunlight and transfers it to the phase change working fluid located within the absorber plate, the phase change working fluid undergoes a phase change and releases heat, and the heat is transferred through the outer wall of the cylindrical jacket to the heat exchange medium located inside the cylindrical jacket; the inlet and outlet pipes include an inlet pipe and an outlet pipe, the heat exchange medium flows into the cylindrical jacket through the inlet pipe and flows out of the cylindrical jacket through the outlet pipe.

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

[0007] Furthermore, the heat-absorbing plate is polygonal in shape, and its outer surface is covered with a heat-absorbing coating.

[0008] Furthermore, reinforcing ribs are welded between the heat-absorbing plate and the cylindrical jacket.

[0009] Furthermore, the cylindrical jacket includes an outer cylindrical wall, a partition, an inner cylindrical wall, an upper sealing cover, and a lower sealing cover; the outer cylindrical wall, the inner cylindrical wall, the upper sealing cover, and the lower sealing cover are tightly spliced ​​to form a cylindrical structure, and the interior of the cylindrical jacket is divided into several jacket units by the partition, each jacket unit serving as a separate heat exchange medium flow channel, and several connected jacket units forming a heat exchange medium flow channel return path.

[0010] Furthermore, the baffles are divided into three types according to the installation method. The return flow of each heat exchange medium channel is completely separated by the first type of baffle, which is sealed between the upper sealing cover and the lower sealing cover. The return flow of each heat exchange medium channel is formed by the second type of baffle and the third type of baffle. The second type of baffle is sealed to the upper sealing cover and is not connected to the lower sealing cover. The third type of baffle is not connected to the upper sealing cover and is sealed to the lower sealing cover. In the return flow of each heat exchange medium channel, the second type of baffle and the third type of baffle are arranged alternately in the circumferential direction.

[0011] Furthermore, each jacket unit is provided with several ribs.

[0012] Furthermore, both the inlet and outlet pipes are arranged perpendicular to the upper sealing cover, and each heat exchange medium flow path return corresponds to a set of inlet and outlet pipes.

[0013] Furthermore, the phase change working medium is metallic tin.

[0014] Furthermore, the heat exchange medium is purified and pressurized air.

[0015] Furthermore, it also includes a molten salt thermal storage layer, which is installed inside the cylindrical jacket.

[0016] The beneficial effects of this invention are:

[0017] 1) The cylindrical jacket has strong pressure-bearing capacity, significantly increasing compressed air pressure and improving heat carrying capacity; at the same time, it has a compact structure, high space utilization, simple manufacturing process, and low operation and maintenance costs. Furthermore, it offers optional reinforcing rib designs to enhance the overall system strength; the form and number of reinforcing ribs can be selected according to actual conditions.

[0018] 2) The use of arc-shaped sealing covers and partitions eliminates the need for pipes during airflow and heat exchange between the jacket units, reducing the number of welds between pipes and the cavity and improving the stability of the absorber. Furthermore, the arc shape can withstand higher air pressures compared to plate covers, preventing damage to the structure from supercritical compressed air flowing within the jacket unit.

[0019] 3) The phase change working fluid is liquid tin, which has the characteristics of low melting point, low viscosity, wide operating temperature range, and high heat transfer efficiency. Liquid tin can operate at higher heat flux densities, improving the heat transfer performance and efficiency of the receiver. Furthermore, its low melting point allows for rapid start-up. When localized high temperatures occur during receiver operation, liquid tin can quickly remove this heat, extending the receiver's service life.

[0020] 4) This receiver structure can heat compressed air to a supercritical state, greatly improving the power generation efficiency of the receiver. Utilizing the heat pipe principle, direct sunlight is avoided, and indirect heat transfer solves problems such as thermal fatigue and thermal ratcheting caused by direct heat transfer, significantly extending the service life of the receiver.

[0021] 5) The cylindrical jacket unit is equipped with fins, which expands the heat transfer area on the compressed air side and increases the residence time of the compressed air, thereby enhancing the heat exchange effect of the air inside the jacket. The higher the air temperature, the greater the pressure, which improves the quality of the high-temperature air produced.

[0022] 6) It provides an optional molten salt thermal storage layer, which can continue to operate by relying on the heat of molten salt when the sun is blocked by clouds. Attached Figure Description

[0023] Figure 1 This is a diagram showing the external shape of the tower-type supercritical air receiver for solar energy according to the present invention.

[0024] Figure 2 This is a pipeline flow diagram of the tower-type supercritical air receiver for solar energy according to the present invention.

[0025] Figure 3 This is a schematic diagram of the operation of the tower-type solar supercritical air receiver of the present invention.

[0026] Figure 4a This is a schematic diagram of the jacket unit of the present invention.

[0027] Figure 4b This is a schematic diagram of the heat exchange fluid flow path between the jacket units of the present invention.

[0028] Figure 5 This is a longitudinal section and a partially enlarged view of the tower-type solar supercritical air absorber of the present invention.

[0029] Figure 6 This is a schematic diagram of the workflow of the present invention.

[0030] The attached diagram is labeled as follows: 1-Absorber plate; 2-Cylindrical jacket; 2.1-Outer wall of cylinder; 2.2-Baffle plate; 2.4-Inner wall of cylinder; 2.5-Upper sealing cover plate; 2.6-Lower sealing cover plate; 3-Inlet and outlet pipes; 3.1-Inlet pipe; 3.2-Outlet pipe; 4-Phase change working medium; 5-Heat exchange medium; 6-Molten salt heat storage layer. Detailed Implementation

[0031] The invention will now be described in further detail with reference to the accompanying drawings.

[0032] like Figure 1 The tower-type supercritical air solar absorber shown consists of an absorber plate 1, a cylindrical jacket 2, and inlet / outlet pipes 3. Sunlight concentrated by a heliostat field shines on the absorber plate 1, and indirect heat transfer occurs through heat pipes, effectively solving problems such as thermal stress and thermal fatigue caused by the large temperature difference from direct heat transfer.

[0033] The heat absorber plate 1 is polygonal in shape, and its plate structure allows sunlight to be distributed more evenly on the surface. The outer surface of the heat absorber plate 1 can be covered with a heat-absorbing coating to enhance its heat absorption capacity. The heat absorber plate material is a high-temperature resistant alloy or other material compatible with the liquid phase change working fluid.

[0034] like Figure 2 and Figure 3 As shown, during operation, the concentrated sunlight is reflected onto the heat absorber plate 1, and the heat is transferred to the interior of the heat absorber plate 1 by absorbing heat and raising the temperature through the heat absorber coating. The phase change working fluid 4 undergoes a phase change after absorbing heat and releases a large amount of heat.

[0035] The phase change working medium 4 uses metallic tin, but is not limited to tin or mixtures of tin with other metals. Tin has a melting point of 231°C and a boiling point as high as 2400°C at room temperature, offering a wide operating temperature range. Due to its low melting point and high boiling point, it is suitable for industrial applications. In terms of safety, metallic tin and its oxides are non-toxic; in the event of a leak, an oxide shell quickly forms on the surface of the metallic tin to prevent further oxidation. The liquefied metallic tin solution has good flow properties, which can enhance heat transfer between tubes. When there is a high local heat flux input, the liquid tin can quickly remove heat, preventing excessively high local temperatures, thus forming efficient and stable heat transfer. This makes the heat flux density on the surface of the absorber plate 1 more uniform, effectively solving problems such as thermal fatigue and thermal ratcheting caused by uneven heating.

[0036] Reinforcing ribs are provided on the outer walls of the heat absorber plate 1 and the cylindrical jacket 2. These ribs are connected between the outer wall of the cylindrical jacket 2 and the heat absorber plate 1 by welding or other processes. Through holes can be provided in the reinforcing ribs, or semi-enclosed ribs can be selected to ensure the flow of molten tin. The type and number of reinforcing ribs can be selected according to actual conditions. The arrangement of the reinforcing ribs can enhance the overall strength of the heat absorber and further ensure stable operation.

[0037] The receiver also features a molten salt heat storage layer 6, which can also employ a jacketed design and contains chloride or fluoride salts. When the sun is obscured by clouds, the molten salt heat storage layer 6 can provide heat to the receiver, ensuring its stable operation.

[0038] like Figure 2 , Figure 4a , Figure 4b and Figure 5 As shown, the cylindrical jacket 2 consists of an outer cylindrical wall surface 2.1, a partition plate 2.2, ribs 2.3, an inner cylindrical wall surface 2.4, an upper sealing cover plate 2.5, and a lower sealing cover plate 2.6. Inside the cylindrical jacket 2, the partition plate 2.2 divides the entire cylinder into several jacket units (W1 to W2). N E1~E N Each jacket unit serves as a separate heat exchange medium flow channel, and several jacket units form a heat exchange medium flow channel return path. The specific number of units can be increased or decreased according to actual needs. The heat exchange medium flow channel return paths are completely separated by baffles 2.2, which also enhance the stability of the cylindrical jacket 2. After the heat exchange medium 5 enters the jacket unit through the inlet pipe 3.1, it flows between the jacket units along the flow channel formed by the baffles 2.2. The heat exchange medium flow channel return path composed of multiple jacket units improves the heat absorption effect of the heat exchange medium 5. After absorbing heat, it enters the expander through the outlet pipe 3.2 to expand and do work, driving the generator to generate electricity.

[0039] Specifically, such as Figure 4b As shown, the baffles 2.2 are divided into three types according to the installation method. The return paths of each heat exchange medium channel are completely separated by the first type of baffle, which is sealed between the upper sealing cover plate 2.5 and the lower sealing cover plate 2.6. Within the return paths of each heat exchange medium channel, the second and third types of baffles form heat exchange medium channels. The second type of baffle is sealed to the upper sealing cover plate 2.5 but not to the lower sealing cover plate 2.6. The third type of baffle is not to the upper sealing cover plate 2.5 but is sealed to the lower sealing cover plate 2.6. In the return paths of each heat exchange medium channel, the second and third types of baffles are arranged alternately circumferentially.

[0040] Each jacket unit is equipped with multiple fins 2.3, and the number of fins 2.3 can be set according to actual needs. Due to the strong pressure bearing capacity of the cylindrical jacket 2, and the presence of fins 2.3 expanding the heat transfer area, fins 2.3 can increase the flow and residence time of compressed air, thereby increasing the temperature of the output compressed air. The higher the temperature and the greater the pressure, the higher the power generation efficiency.

[0041] The upper sealing cover plate 2.5 and the lower sealing cover plate 2.6 are arc-shaped, which can withstand higher pressure compared with plate covers, preventing supercritical compressed air from causing impact damage to the structure when flowing in the jacket unit.

[0042] Both inlet and outlet pipes 3 are perpendicular to the upper sealing cover plate 2.5. The figure shows that they consist of two inlet pipes 3.1 and two outlet pipes 3.2. The heat exchange medium 5 flows into the cylindrical jacket 2 from the inlet pipe 3.1 of the flow channel return flow. After passing through the flow channel composed of multiple jacket units, it flows out from the outlet pipe 3.2 and is then fed into the expander to expand and do work, driving the generator to generate electricity.

[0043] Both the inlet pipe 3.1 and the outlet pipe 3.2 can be composed of a manifold and branch pipes. The manifold has a larger diameter, while the branch pipe has a smaller diameter. The branch pipe connects to the jacket unit. The purified compressed air is input through the inlet manifold, then enters the jacket unit through the branch pipe for heat absorption, and finally enters the outlet manifold through the outlet branch pipe, where it is fed into the expander for expansion and power generation. The specific number of branch pipes can be set according to actual needs.

[0044] The heat exchange medium 5 uses supercritical compressed air. The air is purified before compression to remove solids and impurities. The air pressure can be increased to a certain level by a compressor. Since the cylindrical jacket 2 has a strong pressure-bearing capacity, higher pressure compressed air can be used to improve its heat carrying capacity.

[0045] The working principle of this invention is as follows: Sunlight is reflected by the heliostat field onto the heat absorber plate 1, causing the phase change working medium 4 inside the heat absorber to undergo a phase change and transfer heat indirectly through the heat pipe principle, effectively solving the problems of thermal stress and thermal fatigue caused by the huge temperature difference from direct heat transfer. Heat is transferred to the cylindrical jacket 2 through the heat absorber plate 1. The heat exchange medium 5 entering the cylindrical jacket 2 through the inlet pipe 3.1 is compressed air that has been purified and pressurized to a supercritical state by an air purification device and compressor. The air purification device removes solids and impurities from the air. The compressed air flows through the heat exchange medium flow channel within the cylindrical jacket 2, carrying away the heat transferred to the inside of the cylindrical jacket 2. The multi-pass design and the use of fins 2.3 within the jacket unit allow the compressed air to reach higher temperatures. Once the compressed air reaches the corresponding operating temperature, high-temperature air is output through the outlet pipe 3.2, and then enters the expander to expand and drive the generator. The system is equipped with a selectable molten salt thermal storage layer 6. When the sun is blocked by clouds, the molten salt thermal storage jacket can provide heat to the compressed air, ensuring the normal operation of the absorber.

[0046] 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.

[0047] 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 principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A tower-type solar supercritical air receiver, characterized in that, include: The heat exchange medium consists of a heat-absorbing plate (1), a cylindrical jacket (2), inlet and outlet pipes (3), a phase change working medium (4), and a heat exchange medium (5). The heat-absorbing plate (1) absorbs the heat from sunlight and transfers it to the phase change working medium (4) located inside the heat-absorbing plate (1). The phase change working medium (4) undergoes a phase change and releases heat. The heat is transferred through the outer wall of the cylindrical jacket (2) to the heat exchange medium (5) located inside the cylindrical jacket (2). The inlet and outlet pipes (3) include an inlet pipe (3.1) and an outlet pipe (3.2). The heat exchange medium (5) flows through the inlet pipe. The pipe (3.1) flows into the cylindrical jacket (2) and flows out of the cylindrical jacket (2) through the outlet pipe (3.2); the cylindrical jacket (2) includes an outer wall surface (2.1), a partition (2.2), an inner wall surface (2.4), an upper sealing cover (2.5), and a lower sealing cover (2.6); the outer wall surface (2.1), the inner wall surface (2.4), the upper sealing cover (2.5), and the lower sealing cover (2.6) are tightly spliced ​​to form a cylindrical structure, and the entire cylinder is enclosed inside the cylindrical jacket (2) by the partition (2.2). The structure is divided into several jacketed units, each jacketed unit serving as a separate heat exchange medium channel. Several connected jacketed units form a heat exchange medium return path. The baffles (2.2) are divided into three types according to the installation method. The return paths of each heat exchange medium channel are completely separated by the first type of baffle, which is sealed between the upper sealing cover plate (2.5) and the lower sealing cover plate (2.6). The return paths of each heat exchange medium channel are formed by the second type of baffle and the third type of baffle. The second type of baffle is connected to the upper sealing cover plate (2.6). The sealing plate (2.5) is sealed and connected. The second type of partition is not connected to the lower sealing plate (2.6). The third type of partition is not connected to the upper sealing plate (2.5). The third type of partition is sealed and connected to the lower sealing plate (2.6). In the return flow of each heat exchange medium channel, the second type of partition and the third type of partition are arranged alternately along the circumference. The inlet pipe (3.1) and the outlet pipe (3.2) are both set perpendicular to the upper sealing plate (2.5). Each heat exchange medium channel return flow corresponds to a set of inlet pipe (3.1) and outlet pipe (3.2).

2. A tower-type supercritical air receiver for solar energy as described in claim 1, characterized in that: The heat-absorbing plate (1) is polygonal in shape, and the outer surface of the heat-absorbing plate (1) is covered with a heat-absorbing coating.

3. A tower-type supercritical air receiver for solar energy as described in claim 1, characterized in that: A reinforcing rib is welded between the heat-absorbing plate (1) and the cylindrical jacket (2).

4. A tower-type supercritical air receiver for solar energy as described in claim 1, characterized in that: Each jacket unit is provided with several ribs (2.3).

5. A tower-type supercritical air receiver for solar energy as described in claim 1, characterized in that: The phase change working medium (4) is metallic tin.

6. A tower-type supercritical air receiver for solar energy as described in claim 1, characterized in that: The heat exchange medium (5) is purified and pressurized air.

7. A tower-type supercritical air receiver for solar energy as described in claim 1, characterized in that: It also includes a molten salt thermal storage layer (6), which is installed inside the cylindrical jacket (2).

Images