A heat absorber and a photothermal system

Abstract

The application discloses a heat absorber and a photo-thermal system, and relates to the technical field of solar photo-thermal power generation, which comprises a mounting frame, a salt inlet pipe, a salt outlet pipe, a salt discharge pipeline system and a plurality of heat absorption modules. The mounting frame is in the shape of a columnar body. The heat absorption modules are divided into a plurality of paths on the mounting frame to form a plurality of heat absorption channels. Each heat absorption channel is in the shape of a spiral. The salt inlet pipe is communicated with the heat absorption modules of the lowermost layer of each heat absorption channel. All the heat absorption channels are communicated with the salt outlet pipe above the heat absorption modules of the uppermost layer in the mounting frame to output downward. The salt discharge pipeline system is located below the heat absorption modules of the lowermost layer. The heat absorption modules are communicated with the salt discharge pipeline system. The salt discharge pipeline system is communicated with an external pipeline. The application can ensure the length of the molten salt flow channel and can make the molten salt in the pipeline system flow back to the molten salt storage tank automatically at night.

Description

Technical Field

[0001] This invention relates to the field of solar thermal power generation technology, specifically to a heat absorber and a solar thermal system. Background Technology

[0002] Tower-type concentrated solar power (CSP) technology is becoming increasingly widespread and developed. In tower-type CSP systems, the conversion of light energy into heat energy is accomplished by the receiver, and the related technology of the receiver is one of the most crucial technologies in CSP. The receiver absorbs light energy and converts it into heat energy, which is then absorbed by molten salt, thus heating the molten salt from 290℃ to 570℃. This significant temperature increase requires a certain length of molten salt flow channel; otherwise, it will lead to an increase in heating power density, resulting in a larger heat transfer temperature difference, which is difficult to achieve and can easily cause the receiver to deform, break, or burn out. Furthermore, the surface temperature of the receiver can reach 600℃ to 700℃ during the day, while the ambient temperature can drop to as low as -40℃ at night when it stops operating. Therefore, before the receiver stops operating at night, all molten salt must be returned to the molten salt storage tank to avoid damage to the receiver due to a significant drop in temperature. Summary of the Invention

[0003] This invention aims to address, to a certain extent, one of the technical problems in related technologies. To this end, this invention provides a heat absorber that, while ensuring the length of the molten salt flow channel, allows the molten salt in the pipeline system to automatically flow back to the molten salt storage tank at night.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a heat absorber, comprising a mounting frame, a salt inlet pipe, a salt outlet pipe, a salt discharge pipe system, and a plurality of heat-absorbing modules. The mounting frame is columnar, the salt inlet pipe and the salt outlet pipe are located within the mounting frame, and the plurality of heat-absorbing modules are evenly distributed on the mounting frame, and the plurality of heat-absorbing modules are interconnected to form a heat absorption path.

[0005] The salt inlet pipe is located at the bottom of the mounting frame and is connected to the lowest layer of the heat absorption module of each heat absorption path. All the heat absorption paths converge above the highest layer of the heat absorption module in the mounting frame and are connected to the salt outlet pipe, which outputs the salt downwards.

[0006] An electrically controlled valve is provided between the heat absorption module and the salt discharge pipeline system. The electrically controlled valve is closed when the heat absorber is working and open when the heat absorber is not working.

[0007] In the technical solution provided by this invention, the heat absorption passage is the heating channel of the molten salt. Designing the heat absorption passage in a spatial spiral shape lengthens the molten salt heating channel, preventing absorber burnout caused by increased heating power density. In this invention, changing the dimensions of the cylindrical mounting bracket, whether radial or axial, can lengthen or shorten the molten salt channel. Simultaneously, the cylindrical mounting bracket allows the heat absorption channel to be divided into multiple parallel paths, enabling the absorber to adapt to the actual environment and maximize heat absorption efficiency. Furthermore, the absorber provided by this invention, while ensuring the length of the heat absorption channel, ensures that the molten salt flows from bottom to top, with each absorber tube flowing in the same direction, avoiding dead zones in the molten salt flow and thus preventing absorber damage caused by heat not being carried away by the molten salt in time.

[0008] Meanwhile, when the absorber stops working, the molten salt loses its upward driving force. Therefore, under the action of gravity, the molten salt in the absorber module flows back to the salt discharge pipeline system and is discharged into the molten salt tank of the solar thermal system through the salt discharge pipeline system, thus avoiding the blockage or damage to the absorber caused by the solidification of the molten salt due to a large drop in temperature.

[0009] Optionally, the heat absorption module includes an upper manifold, a lower manifold, and heat absorption pipes. The heat absorption pipes are arranged in an arc shape side by side, with both ends connected to the upper manifold and the lower manifold, respectively. In each heat absorption path, the upper manifold and the lower manifold of adjacent heat absorption modules are connected.

[0010] The bow-shaped absorber tubes can adapt to thermal expansion and contraction caused by large temperature differences, avoiding large thermal stress loads and preventing thermal stress damage to the absorber. At the same time, the side-by-side arrangement of absorber tubes can prevent light leakage and ensure the absorption of sunlight.

[0011] Optionally, the heat absorption tube is divided into two passages at each end. The two passages at the upper end are connected to the upper manifold, and the two passages at the lower end are connected to the lower manifold, so that the heat absorption tube can be easily welded to the upper and lower manifolds.

[0012] Optionally, the heat absorber further includes a balance tank, which is located above the top heat absorption module. All modules have a first exhaust pipe on their upper manifolds, and the first exhaust pipe is connected to the balance tank.

[0013] When the heat absorber module is empty of molten salt, it will inevitably be filled with air. When the heat absorber module enters its working state, molten salt enters. At this time, the air inside the heat absorber module is expelled through the exhaust pipe, ensuring that the molten salt can smoothly enter the heat absorber module. Simultaneously, the exhaust pipe is connected to the balance tank, rather than directly to the atmosphere, ensuring that any small amount of molten salt entering the exhaust pipe is collected in the balance tank, preventing the molten salt from being directly thrown through the exhaust pipe and causing the heat absorber to burn out.

[0014] Optionally, the salt outlet pipe is U-shaped with the opening of the U facing downwards. One end is connected to a heat absorption passage, and the other end is connected to an external pipe. A second vent pipe is provided at the upper part of the bend of the U-shape. The second vent pipe is connected to the balance tank, which helps to ensure that the vent pipe can vent smoothly and completely, and ensures that the molten salt flows out smoothly from the salt outlet pipe.

[0015] Optionally, the balance tank is equipped with an overflow pipe, which is connected to the salt discharge pipeline system and to an external pipeline.

[0016] Optionally, the heat absorber is characterized in that the balance tank is provided with a vent pipe, the vent pipe connecting the interior and exterior of the balance tank.

[0017] The molten salt in the heat absorption module inevitably enters the balance tank through the exhaust pipe. However, the balance tank has a limited volume. When the pump pressure fluctuates greatly, the excess molten salt can be discharged through the overflow pipe before the balance tank is full, thus preventing the molten salt from overflowing from the balance tank and causing the heat absorber to burn out.

[0018] Optionally, the lower manifold is equipped with a salt discharge pipe, which is connected to the salt discharge pipeline system.

[0019] Optionally, the salt inlet pipe is connected to each heat absorption path through a distributor, and each heat absorption path is connected to the salt outlet pipe through a confluencer.

[0020] The distributor ensures that the molten salt is evenly distributed to each heat absorption path, and the confluencer ensures that the molten salt in each heat absorption path is fully and uniformly mixed.

[0021] In addition, the present invention also provides a photothermal system, including a cold salt tank, a cold salt pump tank, a hot salt tank, a heliostat, and the absorber described in any one of the foregoing.

[0022] The photothermal system includes a working state and a non-working state. In the working state, molten salt in the cold salt tank is pumped into the absorber by the cold salt pump tank, the heliostat focuses and reflects sunlight to the absorber, and the absorber heats the molten salt and then delivers it to the hot salt tank. In the non-working state, the molten salt in the absorber is collected by the salt discharge pipeline system and flows into the cold salt tank.

[0023] The beneficial effects of the photothermal system provided by this invention are similar to the reasoning process of the beneficial effects of the aforementioned heat absorber, and will not be repeated here.

[0024] Optionally, a cold salt buffer tank and two one-way valves are provided between the cold salt pump tank and the heat absorber, with the cold salt buffer tank located between the two one-way valves.

[0025] In a solar thermal system, molten salt is pumped into the receiver via a cold salt pump tank. However, if an unexpected situation occurs causing the cold salt pump tank to shut down, the molten salt will lose its driving force and flow back along the pipeline. A one-way valve can prevent the backflow of molten salt into the cold salt pump tank, which could damage the pump. Simultaneously, the shutdown of the cold salt pump tank will result in no molten salt flow within the receiver, potentially leading to dry-burning damage from sunlight. A cold salt buffer tank can pressurize the stored cold salt into the receiver, maintaining molten salt flow within the receiver for a period of time. This provides valuable time for emergency response and prevents the receiver from drying out and being damaged.

[0026] Optionally, a hydraulically controlled electric valve is provided between the cold salt tank and the cold salt pump tank to control the intake of the cold salt pump tank, thereby controlling the flow rate of molten salt in the photothermal system.

[0027] Optionally, the outlet of the salt discharge pipeline system is equipped with an electric valve. When the solar thermal system is in operation, the electric valve is closed to prevent molten salt from flowing out of the salt discharge pipeline system. When the solar thermal system is not in operation, the electric valve is open, and the molten salt can be discharged back to the cold salt tank from the salt discharge pipeline system, thus avoiding damage to the absorber caused by a significant drop in temperature.

[0028] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of the present invention will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. In addition, each of these features, elements and components appearing in the following text and drawings is a plurality of, and different symbols or numbers are used for convenience of representation, but all represent parts with the same or similar construction or function. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings:

[0030] Figure 1 This is a three-dimensional schematic diagram of the heat absorber in an embodiment of the present invention;

[0031] Figure 2 This is a side view of the heat absorber in an embodiment of the present invention;

[0032] Figure 3 This is a three-dimensional schematic diagram of the heat absorption channel in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the heat absorption module in an embodiment of the present invention;

[0034] Figure 5 This is a side view of the heat absorption module in an embodiment of the present invention;

[0035] Figure 6 This is a topological diagram of the heat absorber in an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the photothermal system in an embodiment of the present invention.

[0037] Among them, 2-salt inlet pipe, 3-diffusion separator, 4-merging device, 5-salt outlet pipe, 51-second exhaust pipe, 6-salt discharge pipeline system, 7-balance tank, 71-U-shaped vent pipe, 72-overflow pipe, 8-heat absorption module, 81-heat absorption pipe, 82-upper manifold, 83-lower manifold, 84-first exhaust pipe, 85-salt discharge pipe, 100-cold salt tank, 200-cold salt pump tank, 300-hot salt tank, 400-heliostat, 500-heat absorber, 600-cold salt buffer tank. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain the present invention and should not be construed as limiting the invention.

[0039] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this patent. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0040] Example:

[0041] like Figure 1 , Figure 2 and Figure 3 As shown, this embodiment provides a heat absorber 500, including a mounting bracket, a salt inlet pipe 2, a distributor 3, a confluencer 4, a salt outlet pipe 5, a salt discharge pipeline system 6, a balance tank 7, and several heat absorption modules 8.

[0042] like Figure 3 As shown, the mounting bracket, shaped like a column, is used to mount the heat-absorbing module 8. Since the heat-absorbing module 8 is generally flat, the cross-section of the columnar mounting bracket is a regular polygon. In this embodiment, the mounting bracket is columnar, and its outer surface is provided with several hooks (not shown in the figure). The heat-absorbing modules 8 are mounted on the hooks on the outer surface of the mounting bracket, evenly distributed throughout the bracket. Figure 4As shown, the heat absorption module 8 is divided into several interconnected heat absorption channels, each of which is spiral-shaped, serving as the heating channel for the molten salt. Designing it as a spatial spiral lengthens the molten salt heating channel, preventing the absorber 500 from burning out due to increased heating power density. This embodiment does not limit the size of the mounting bracket; changing the dimensions of the columnar mounting bracket, whether radial or axial, can lengthen or shorten the molten salt channel. Furthermore, the columnar mounting bracket allows for multiple parallel heat absorption channels, enabling the absorber 500 to adapt to the environment and maximize heat absorption efficiency.

[0043] like Figure 5 and Figure 6 As shown, the heat absorption module 8 includes an upper manifold 82, a lower manifold 83, and a heat absorption pipe 81, which is arc-shaped. The arc shape can be either curved or semi-circular; in this embodiment, a semi-circular arc shape is preferred. The arc-shaped heat absorption pipe 81 can adapt to thermal expansion and contraction caused by large temperature differences, avoiding large thermal stress loads and preventing damage to the heat absorber 500 due to thermal stress. The two ends of the arc shape are divided into left and right passages. The left and right passages at the upper end connect to the side walls of the upper manifold 82, and the left and right passages at the lower end connect to the side walls of the lower manifold 83. These left and right passages facilitate welding of the heat absorption pipe 81 to the upper and lower manifolds. The arc-shaped heat absorption pipes 81 are arranged side-by-side between the upper manifold 82 and the lower manifold 83. This side-by-side arrangement prevents light leakage and ensures the absorption of sunlight. Furthermore, the heat absorption pipe 81 is coated with a heat-absorbing coating to improve the conversion efficiency of light energy into heat energy. In each heat absorption path, the upper manifold 82 and lower manifold 83 of adjacent heat absorption modules 8 are connected to ensure that the molten salt in each heat absorption path can pass through all heat exchange modules in that heat absorption path.

[0044] like Figure 1 , Figure 2 and Figure 4 As shown, the salt inlet pipe 2 and the salt outlet pipe 5 are located within the mounting frame. The salt inlet pipe 2 is located at the bottom of the mounting frame and is connected to the lowest layer of the heat absorption module 8 in each heat absorption path. In this embodiment, the salt inlet pipe 2 is connected to each heat absorption path through a distributor 3, which ensures that the molten salt is evenly distributed to each heat absorption path. The number of distributors 3 can distribute is equal to the number of heat absorption paths and corresponds one-to-one. All heat absorption paths converge above the highest layer of heat absorption module 8 within the mounting frame and are connected to the salt outlet pipe 5 by a confluencer 4. The salt outlet pipe 5 is U-shaped with the U-shaped opening facing downwards. One end is connected to each heat absorption path simultaneously through the confluencer 4, and the other end is connected to an external pipe. Figure 2As shown, the confluencer 4 only needs to be slightly above the top heat absorption module 8 to ensure that the molten salt flows horizontally or from bottom to top. The confluencer 4 combines the molten salt in each heat absorption path and transports it to the salt outlet pipe 5, from which it is then output downwards. The molten salt enters each heat absorption path from the distributor 3 below the heat absorber 500 and flows upwards, converging above the heat absorber 500 before being output. While ensuring the length of the heat absorption channels, the molten salt flows from bottom to top, with each heat absorption tube flowing in the same direction, avoiding dead zones in the molten salt flow and thus preventing damage to the heat absorber 500 due to heat not being carried away by the molten salt in time.

[0045] like Figure 2 , Figure 4 and Figure 6 As shown, the balance tank 7 is located above the confluencer 4. Each heat-absorbing module 8 has a first exhaust pipe 84 on its upper manifold 82, and each first exhaust pipe 84 is connected to the bottom of the balance tank 7. When there is no molten salt in the heat-absorbing module 8, the heat-absorbing module 8 will inevitably be filled with air. When the heat-absorbing module 8 enters the working state, molten salt enters the heat-absorbing module 8. At this time, the air in the heat-absorbing module 8 can be discharged through the first exhaust pipe 84, ensuring that the molten salt can smoothly enter the heat-absorbing module 8. The first exhaust pipe 84 is connected to the balance tank 7 instead of being directly connected to the atmosphere, which ensures that a small amount of molten salt entering the first exhaust pipe 84 can be collected into the balance tank 7, avoiding the molten salt from being directly thrown out through the first exhaust pipe 84 and causing the heat absorber 500 to burn out. The U-shaped bend of the salt outlet pipe 5 is also connected to the bottom of the balance tank 7 through the second exhaust pipe 51, which helps to ensure that the venting of the salt outlet pipe 5 is smooth and thorough, ensuring that the molten salt flows out smoothly from the salt outlet pipe 5. Furthermore, the balance tank 7 is also equipped with a U-shaped vent pipe 71 and an overflow pipe 72. The U-shaped vent pipe 71 is located at the top of the balance tank 7, with its opening facing downwards, connecting the inside and outside of the balance tank 7. The overflow pipe 72 is connected to an external pipeline. Molten salt in the heat absorption module 8 inevitably enters the balance tank 7 through the first exhaust pipe 84. However, the balance tank 7 has a limited volume. When the pump pressure fluctuates significantly, the air inside the balance tank 7 can be vented into the surrounding air through the U-shaped vent pipe 71, maintaining a balanced pressure inside the balance tank 7. The overflow pipe 72 can discharge excess molten salt before the balance tank 7 is full, preventing molten salt from overflowing from the balance tank 7 and causing the heat absorber 500 to burn out. Each heat absorption module 8 has a first salt discharge pipe 85 in its lower manifold 83. The first salt discharge pipe 85 is connected to the salt discharge pipeline system 6, which is located below the lowest layer of heat absorption modules 8. In this embodiment, the salt discharge pipeline system 6 is ring-shaped, and the overflow pipe 72 is connected to the salt discharge pipeline system 6, thereby connecting to the external pipeline. When the absorber 500 stops working, the molten salt loses the upward driving force, so under the action of gravity, the molten salt in the absorber module 8 flows back to the salt discharge pipeline system 6 and is discharged into the molten salt tank of the solar thermal system through the salt discharge pipeline system 6, avoiding blockage or damage to the absorber 500 caused by the solidification of the molten salt due to a large drop in temperature.

[0046] In this embodiment, since there are multiple heat-absorbing modules 8, there are also multiple spatial spiral-shaped heat-absorbing passages. Furthermore, each heat-absorbing module 8 is connected to the balance tank 7 and the salt discharge pipeline system 6. Therefore, for clarity, the pipe connections between some pipelines are not shown in the figure.

[0047] This embodiment also provides a photothermal system, now combined with Figure 7 The topology diagram of the absorber 500 provides a detailed description of the photothermal system and the absorber 500 provided in this embodiment:

[0048] like Figure 7 As shown, the photothermal system provided in this embodiment includes a cold salt tank 100, a cold salt pump tank 200, a hot salt tank, a heliostat 400, and the aforementioned absorber 500. The arrows in the figure indicate the direction of molten salt flow.

[0049] A cold salt tank 100 is connected to a cold salt pump tank 200, and a hydraulically controlled electric valve is installed between them to control the intake of the cold salt pump tank 200, thereby controlling the flow rate of molten salt in the solar thermal system. The electric valve is shown in the figure and is a common symbol in the art; those skilled in the art can determine its location by reading the specification and accompanying drawings. The cold salt pump tank 200 is connected to the salt inlet pipe 2 of the absorber 500, and molten salt is pumped into the absorber 500 through the cold salt pump in the cold salt pump tank 200. Simultaneously, a cold salt buffer tank 600 and two one-way valves are provided between the cold salt pump tank 200 and the absorber 500, with the cold salt buffer tank 600 positioned between the two one-way valves. The one-way valves are shown in the figure and are common symbols in the art; those skilled in the art can determine their location by reading the specification and accompanying drawings. When an unexpected situation occurs in the solar thermal system causing the cold salt pump tank 200 to stop, the molten salt will lose its driving force and flow backward along the pipeline. A one-way valve prevents backflow of molten salt into the cold salt pump tank 200, thus preventing damage to the cold salt pump tank 200. Simultaneously, a shutdown of the cold salt pump tank 200 will result in no molten salt flow within the receiver 500, leading to dry-burning damage from sunlight. The cold salt buffer tank 600 can pressurize the stored cold salt into the receiver 500, maintaining molten salt flow within the receiver 500 for a period of time, buying valuable time for emergency response and preventing dry-burning damage to the receiver 500. The heliostat 400 irradiates the receiver 500, and the salt outlet pipe 5 of the receiver 500 is connected to the hot salt tank 300. Simultaneously, the salt discharge pipeline system 6 of the receiver 500 is connected to the cold salt tank 100, and an electric valve is installed at the outlet of the salt discharge pipeline system 6. The solar thermal system includes a working state and a non-working state. When the solar thermal system is in the working state, the electric valve is closed to prevent molten salt from flowing out of the salt discharge pipeline system 6. When the solar thermal system is in the non-working state, the electric valve is open, and the molten salt can return from the salt discharge pipeline system 6 to the cold salt tank 100, thus avoiding damage to the absorber 500 caused by a large drop in temperature.

[0050] like Figure 7As shown in the figure, the arrows indicate the direction of molten salt flow. In operation, the molten salt in the cold salt tank 100 is pumped into the salt inlet pipe 2 of the absorber 500 by the cold salt pump in the cold salt pump tank 200. The molten salt in the salt inlet pipe 2 is then evenly distributed to each heat absorption path by the distributor 3. Under the action of the cold salt pump, the molten salt flows from bottom to top in the heat absorption path. The heliostat 400 focuses and reflects sunlight onto the heat absorption module 8 of the absorber 500. The heat absorption module 8 absorbs the light energy and converts it into heat energy, causing the molten salt to heat up. At this time, the electric valve at the outlet of the salt discharge pipeline system 6 closes. When the molten salt enters the heat absorption module 8, the air in the heat absorption module 8 is discharged into the balance tank 7 through the first exhaust pipe 84. The electric valve is shown in the figure and is a common symbol in the art; those skilled in the art can determine its location by reading the specification and the accompanying drawings. During this process, some molten salt inevitably enters the balance tank 7 through the first exhaust pipe 84. Therefore, the air inside the balance tank 7 is discharged through the U-shaped vent pipe 71. If the molten salt in the balance tank 7 is full, it flows back to the salt discharge pipeline system 6 through the overflow pipe 72, and then back to the cold salt tank 100. The molten salt flowing from bottom to top in each heat absorption path is heated by the heat absorption module 8 and then collected by the confluencer 4. The confluencer 4 ensures that the molten salt in each heat absorption path is fully and uniformly mixed. Then it is transported to the hot salt tank 300 through the salt outlet pipe 5.

[0051] When not in operation, the cold salt pump stops working, the electric valve at the outlet of the salt discharge pipeline system 6 opens, the molten salt loses the upward driving force, and therefore the molten salt in the absorber 500 flows back to the collecting pipe from top to bottom under the action of gravity, and is collected in the salt discharge pipeline system 6 and discharged into the cold salt tank 100.

[0052] Meanwhile, a pipeline connecting the check valve and the salt inlet pipe 2 to the manifold is also installed in the pipeline, and an electric valve is installed in the pipeline. When an unexpected situation occurs in the solar thermal system and the cold salt pump tank 200 stops, the electric valve opens, and the molten salt that was prevented from flowing into the cold salt buffer tank 600 by the check valve can flow back to the salt discharge pipeline system 6 through this pipeline, and then be discharged into the cold salt tank 100. The check valve and the electric valve are shown in the figure and are common symbols in the art. Those skilled in the art can know the location of the check valve and the electric valve after reading the specification and the accompanying drawings.

[0053] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A heat absorber, characterized in that, The heat absorber includes a mounting frame, a salt inlet pipe, a salt outlet pipe, a salt discharge pipeline system, and several heat absorption modules. The mounting frame is columnar, the salt inlet pipe and the salt outlet pipe are located inside the mounting frame, and several heat absorption modules are evenly distributed on the mounting frame. The heat absorption modules are divided into several interconnected paths to form several heat absorption channels, and each heat absorption channel is spiral-shaped. The salt inlet pipe is located at the bottom of the mounting frame and is connected to the lowest layer of the heat absorption module of each heat absorption path. All the heat absorption paths converge above the highest layer of the heat absorption module in the mounting frame and are connected to the salt outlet pipe, which outputs the salt downwards. The salt discharge pipeline system is located below the lowest heat absorption module. The heat absorption module is connected to the salt discharge pipeline system, and the salt discharge pipeline system is connected to external pipelines. The heat absorption module includes an upper manifold, a lower manifold, and heat absorption pipes. The heat absorption pipes are arranged side by side in an arc shape, with both ends connected to the upper manifold and the lower manifold, respectively. In each heat absorption path, the upper and lower manifolds of adjacent heat absorption modules are connected. The heat absorber also includes a balance tank, which is located above the uppermost heat absorption module. The upper manifold has a first exhaust pipe, which is connected to the balance tank. The salt outlet pipe is U-shaped, with the opening of the U-shape facing downwards. One end is connected to a heat absorption path, and the other end is connected to an external pipe. A second exhaust pipe is located at the upper part of the bend of the U-shape, which is connected to the balance tank. The lower manifold has a salt discharge pipe, which is connected to the salt discharge pipeline system.

2. The heat absorber according to claim 1, characterized in that, The heat absorption tube is divided into two passages at each end. The two passages at the upper end are connected to the upper manifold, and the two passages at the lower end are connected to the lower manifold.

3. The heat absorber according to claim 2, characterized in that, The balance tank is equipped with an overflow pipe, which is connected to the salt discharge pipeline system and to an external pipeline.

4. The heat absorber according to claim 2, characterized in that, The balance tank is equipped with a vent pipe that connects the inside and outside of the balance tank.

5. The heat absorber according to any one of claims 1 to 4, characterized in that, The salt inlet pipe is connected to each heat absorption path through a distributor, and each heat absorption path is connected to the salt outlet pipe through a confluencer.

6. A photothermal system, characterized in that, The photothermal system includes a cold salt tank, a cold salt pump tank, a hot salt tank, a heliostat, and a heat absorber as described in any one of claims 1 to 5; The photothermal system includes a working state and a non-working state. In the working state, molten salt in the cold salt tank is pumped into the absorber by the cold salt pump tank, the heliostat focuses and reflects sunlight to the absorber, and the absorber heats the molten salt and then delivers it to the hot salt tank. In the non-working state, the molten salt in the absorber is collected by the salt discharge pipeline system and flows into the cold salt tank.

7. The photothermal system according to claim 6, characterized in that, A cold salt buffer tank and two one-way valves are provided between the cold salt pump tank and the heat absorber, with the cold salt buffer tank located between the two one-way valves.

8. The photothermal system according to claim 6, characterized in that, A hydraulically controlled electric valve is provided between the cold salt tank and the cold salt pump tank.

9. The photothermal system according to claim 8, characterized in that, The outlet of the salt discharge pipeline system is equipped with an electric valve.

Images