A self-circulating tower solar heat absorber and a method for operating the same

Abstract

The application relates to a self-circulating tower type solar heat absorber and a running method thereof, which comprises a heat absorbing device and a heat exchanging device; the heat absorbing device comprises a channel for the flow of a heat conducting medium, the channel comprises a heat absorbing part and a heat exchanging part capable of carrying out heat exchange with the heat exchanging device; the heat absorbing device is further provided with a medium pushing piece; the medium pushing piece can float in the heat absorbing part, can move from the upper end of the heat absorbing part to the upper end of the heat exchanging part, can sink in the heat exchanging part, and can move from the lower end of the heat exchanging part to the lower end of the heat absorbing part, so as to push the heat conducting medium to circulate in the channel, and the application has the advantages of reducing the manufacturing cost and the use cost.

Description

Technical Field

[0001] This invention relates to the technical field of solar thermal power generation, and in particular to a self-circulating tower solar absorber and its operation method. Background Technology

[0002] Tower solar power generation is a type of solar thermal power generation and is one of the important ways to utilize solar energy in the future.

[0003] Therefore, concentrated solar power (CSP) has significant future development potential, and tower solar power, due to its superior characteristics, will remain the main type of CSP. However, the high cost and difficulty in manufacturing key components such as receivers and molten salt pumps have prevented tower solar power technology from reaching commercialization levels. For example, the existing receiver structures of tower solar power plants are basically imitations of the American SOLAR TWO system receivers, with only minor modifications and improvements, without fundamental changes to the receiver structure. Molten salt pumps are also essential equipment, so the difficulties in manufacturing and high costs remain, severely restricting the development of tower solar power in my country.

[0004] In conclusion, how to reduce the difficulties in equipment processing, high manufacturing and operating costs in tower solar power generation is a problem worth considering. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a self-circulating tower solar absorber and its operation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A self-circulating tower-type solar absorber includes: a heat-absorbing device and a heat-exchanging device; the heat-absorbing device includes a channel for the flow of a heat-conducting medium, the channel including a heat-absorbing part and a heat-exchanging part capable of exchanging heat with the heat-exchanging device; the heat-absorbing device is further provided with a medium-propelling member; the medium-propelling member is configured to: float within the heat-absorbing part, move from the upper end of the heat-absorbing part to the upper end of the heat-exchanging part, sink within the heat-exchanging part, and move from the lower end of the heat-exchanging part to the lower end of the heat-absorbing part, so as to promote the circulation of the heat-conducting medium within the channel.

[0008] Preferably, the heat-conducting medium located within the heat-absorbing section has a first temperature; the density of the heat-conducting medium at the first temperature is greater than the density of the medium-propelling member at the first temperature.

[0009] Preferably, the heat-conducting medium located within the heat exchange section has a second temperature; the density of the heat-conducting medium at the second temperature is less than the density of the medium-driven member at the second temperature.

[0010] Preferably, the medium pushing member is configured as a plurality of hollow spheres or a plurality of hollow cylinders.

[0011] Preferably, the channel further includes an upper conductive section and a lower conductive section; the upper conductive section connects the heat-absorbing section and the upper end of the heat-exchange section, and the lower conductive section connects the heat-absorbing section and the lower end of the heat-exchange section; the upper conductive section is provided with upper guide arc segments on both sides near the heat-absorbing section and the heat-exchange section; the lower conductive section is provided with lower guide arc segments on both sides near the heat-absorbing section and the heat-exchange section.

[0012] Preferably, the heat absorption device further includes a heat insulation plate separating the heat absorption section and the heat exchange section; the heat insulation plate has a first wall surface facing the heat absorption section and a second wall surface facing the heat exchange section; when the medium pushing member is located in the heat absorption section, its outer wall surface is in contact with the first wall surface and also in contact with the inner wall surface of the heat absorption section opposite to the first wall surface; when the medium pushing member is located in the heat exchange section, its outer wall surface is in contact with the second wall surface and also in contact with the inner wall surface of the heat exchange section opposite to the second wall surface.

[0013] Preferably, an exhaust valve is also provided at the upper end of the channel.

[0014] Preferably, the heat exchange device includes a heat exchange element, which is detachably disposed on one side of the heat exchange section; the water inlet end of the heat exchange element is connected to a water pump through a water inlet pipe, and the water outlet end of the heat exchange element is connected to a steam turbine through a water outlet pipe.

[0015] A method for operating a self-circulating tower solar absorber as described above includes: an absorber section absorbing solar energy to raise the temperature of a heat-conducting medium located within the absorber section; a medium-propelling member located within the absorber section rising and propelling the heat-conducting medium within the absorber section from the absorber section to a heat exchange section; the heat exchange section exchanging heat with a heat exchange device; the temperature of the heat-conducting medium within the heat exchange section decreasing; and the medium-propelling member located within the heat exchange section sinking and propelling the heat-conducting medium within the heat exchange section from the heat exchange section to the absorber section.

[0016] Preferably, an exhaust valve is used to release steam to reduce the pressure inside the channel.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention utilizes the temperature changes of the heat-absorbing and heat-exchange sections to cause the medium-propelling component to rise in the heat-absorbing section and sink in the heat-exchange section, thereby driving the heat-conducting medium to circulate and form a self-circulating system. On the one hand, the channel structure is simple, the operation and maintenance cost is low, and the use of expensive molten salt pumps can be avoided, thus avoiding the complex structural settings such as heat preservation and heat tracing required for long-distance molten salt pipeline transportation, which can effectively reduce the manufacturing and use costs of the equipment. On the other hand, the floating and sinking of the medium-propelling component is controlled by the temperature of the heat-conducting medium in the heat-absorbing and heat-exchange sections, while also carrying the heat-conducting medium in circulation, without the need for external power intervention, resulting in even lower operating costs.

[0019] 2. The present invention places the heat-conducting medium in the fluid within the channel of the heat-absorbing part. Compared with the case where steam is directly used as the heat-absorbing / heat-conducting medium, the uneven light exposure on the light-receiving side can easily lead to local overheating and pipe bursting. At the same time, it can also avoid the situation where the steam pipe is subjected to high-concentration light radiation, resulting in large temperature and pressure fluctuations.

[0020] 3. The heat absorption device only needs to meet the temperature change and drive the heat transfer medium to flow. The light-receiving surface of its heat absorption part can be set as a plane. The overall system is significantly simpler than the traditional structure, and its manufacturing difficulty is lower. In addition, the heat exchange device and heat exchange part can be detached and connected, and the replacement of each structure is also easier. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a self-circulating tower solar absorber structure provided by the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Heat absorption device; 10. Heat transfer medium; 11. Channel; 111. Heat absorption section; 1111. Heat absorption plane; 112. Heat exchange section; 113. Upper conductive section; 1131. Upper guide arc section; 114. Lower conductive section; 1141. Lower guide arc section; 12. Medium pushing component; 13. Heat insulation plate; 131. First wall surface; 132. Second wall surface; 2. Heat exchange device; 21. Heat exchange component; 22. Inlet water pipe; 23. Outlet water pipe; 3. Exhaust valve; 4. Water pump; 5. Steam turbine. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] See Figure 1 This invention provides a self-circulating tower solar absorber, comprising: a heat absorption device 1 and a heat exchange device 2; the heat absorption device 1 can absorb solar energy and convert it into heat energy to supply the heat exchange device 2, thereby effectively utilizing the heat energy.

[0029] Specifically, the heat absorption device 1 includes a channel 11 for the flow of the heat transfer medium 10. The channel 11 includes a heat absorption section 111 and a heat exchange section 112 capable of exchanging heat with the heat exchange device 2. The heat absorption device 1 is equipped with a medium pushing member 12. The medium pushing member 12 is configured to: float in the heat absorption section 111, move from the upper end of the heat absorption section 111 to the upper end of the heat exchange section 112, sink in the heat exchange section 112, and move from the lower end of the heat exchange section 112 to the lower end of the heat absorption section 111, so as to push the heat transfer medium 10 to circulate in the channel 11.

[0030] Furthermore, to achieve the flow of the heat-conducting medium 10 driven by the medium-driven component 12, the heat-conducting medium 10 can generally be a molten salt, or other high-temperature resistant material, as long as it remains in a stable liquid state within the operating temperature range. The heat-conducting medium 10 can be a medium with a large density change within the operating temperature range, and the medium-driven component 12 can be made of a material with good expansion properties and a significant change in volume and density with temperature difference, so that the relative density change between the two is such that the density of the heat-conducting medium 10 at the first temperature is greater than the density of the medium-driven component 12 at the first temperature, and the density of the heat-conducting medium 10 at the second temperature is less than the density of the medium-driven component 12 at the second temperature. The specific setting can be determined according to the temperature range of the operating range on site.

[0031] Furthermore, the heat-absorbing device 1 is placed at the top of the tower to absorb and convert the energy reflected and gathered from the solar energy field, that is, to convert solar radiation energy into heat energy. Specifically, the heat-absorbing part 111 has a heat-absorbing plane 1111, which can be coated with a heat-absorbing coating with high absorptivity and low reflectivity and emissivity. The heat-absorbing plane 1111 covers the bottom of the heat-absorbing part 111, ensuring that the bottom of the heat-absorbing part 111 can be radiated by reflected light, so that the medium pushing member 12 has sufficient buoyancy to float when it is located at the bottom of the heat-absorbing part 111. The heat-absorbing plane 1111 faces the radiation of the solar energy field to convert solar radiation energy into heat energy and store it in the heat-conducting medium 10 located in the heat-absorbing part 111.

[0032] As the heat-conducting medium 10 absorbs heat energy, it reaches a first temperature within the heat-absorbing section 111. This causes a relative change in the density of both the heat-conducting medium 10 and the medium-propelling member 12. The density of the heat-conducting medium 10 at the first temperature is greater than that of the medium-propelling member 12 at the first temperature. The medium-propelling member 12 then floats within the heat-absorbing section 111, carrying the heat-conducting medium 10 at the first temperature to the heat exchange section 112 for heat exchange with the heat exchange device 2. As the heat exchange section 112 and the heat exchange device 2 exchange heat, the heat-conducting medium 10 within the heat exchange section 112 reaches a second temperature, which is lower than the first temperature. The density of the heat-conducting medium 10 at the second temperature is less than that of the medium-propelling member 12 at the second temperature. The medium-propelling member 12 then sinks within the heat exchange section 112, carrying the heat-conducting medium 10 that has undergone heat exchange back to the heat-absorbing section 111 for heat absorption, thus completing the heat absorption and heat exchange cycle of the heat-conducting medium 10.

[0033] The medium-driven component 12 can be configured as several hollow spheres or several hollow cylinders. For example, the buoyancy spheres can be made of materials such as stainless steel alloy. By controlling the thickness and size, its buoyancy characteristics can be optimized. Furthermore, the thickness of the hollow spheres or hollow cylinders can be determined according to the specific usage conditions on site to adjust the density change of the medium-driven component 12 to match the heat-conducting medium 10.

[0034] Furthermore, channel 11 also includes an upper conductive section 113 and a lower conductive section 114; the upper conductive section 113 connects the heat absorption section 111 and the upper end of the heat exchange section 112, and the lower conductive section 114 connects the heat absorption section 111 and the lower end of the heat exchange section 112; the medium pushing member 12 floats from the heat absorption section 111 to one end of the upper conductive section 113, and passes through the upper conductive section 113 into the heat exchange section 112. In order to improve the effect of the medium pushing member 12 in pushing the fluid and to ensure smooth upper conductive flow, In this embodiment, the medium pushing member 12 can be configured as a plurality of hollow spheres or hollow cylinders arranged in parallel series. The diameter of the hollow spheres or hollow cylinders is smaller than the longitudinal width of the upper conducting part 113 and the lower conducting part 114. Specifically, the longitudinal width of the upper conducting part 113 and the lower conducting part 114 can be set to 1.2 to 1.5 times the diameter of the hollow spheres or hollow cylinders, so that the small spheres can pass freely while maintaining the temperature difference between the heat absorption part 111 and the heat exchange part 112.

[0035] Furthermore, several medium-driven components 12 can be provided. The upper conductive section 113 is provided with upper guide arc segments 1131 on both sides near the heat absorption section 111 and the heat exchange section 112. The upper guide arc segments 1131 guide the direction of movement, so that the medium-driven component 12 can smoothly pass through the upper conductive section 113 under the action of its own buoyancy and the thrust of the heat-conducting medium 10 or the thrust of another medium-driven component 12. Similarly, the lower conductive section 114 is provided with lower guide arc segments 1141 on both sides near the heat absorption section 111 and the heat exchange section 112. The lower guide arc segments 1141 guide the flow direction, so that the medium-driven component 12 can smoothly pass through the lower conductive section 114 under the action of its own weight and the thrust of the heat-conducting medium 10 or the thrust of another medium-driven component 12.

[0036] In order to increase the heat insulation effect of the heat absorption part 111 and the heat exchange part 112, the heat absorption device 1 also includes a heat insulation plate 13 separating the heat absorption part 111 and the heat exchange part 112. The heat insulation plate 13 can be filled with heat insulation material to increase the heat insulation effect.

[0037] Specifically, the heat insulation plate 13 has a first wall surface 131 facing the heat absorption part 111 and a second wall surface 132 facing the heat exchange part 112. In order to facilitate the movement of the medium pushing member 12, in this embodiment there may be a certain gap between the medium pushing member 12 and the first wall surface 131 and the second wall surface 132 of the heat insulation plate 13. In order to ensure that the gap does not affect the circulation of the heat transfer medium 10, the gap may be set to 1 to 2 mm. Of course, in other embodiments, when the medium pushing member 12 is located inside the heat absorption section 111, its outer wall surface is in contact with the first wall surface 131 and also with the inner wall surface of the heat absorption section 111 opposite to the first wall surface 131, so that the gap between the medium pushing member 12 and the inner wall surface of the heat absorption section 111 is small, avoiding the heat-conducting medium 10 from being retained in the heat absorption section 111 during the upward movement of the medium pushing member 12; similarly, when the medium pushing member 12 is located inside the heat exchange section 112, its outer wall surface is in contact with the second wall surface 132 and also with the inner wall surface of the heat exchange section 112 opposite to the second wall surface 132. The volume of the heat-conducting medium 10 can occupy 85% to 95% of the volume of the channel 11, and can also fill the entire channel 11, so that the heat-conducting medium 10 can circulate when affected by the force of the movement of the medium pushing member 12.

[0038] Since the heat transfer medium 10 may generate bubbles when heated, and rise to the upper end of the heat absorption part 111, the upper end of the heat exchange part 112 and the upper conduction part 113, an exhaust valve 3 can be provided at the upper end of the channel 11 to discharge the bubbles when the air pressure is too high due to the presence of bubbles inside the channel 11.

[0039] The heat exchange device 2 of this invention can be used to convert the thermal energy in the heat transfer medium 10 into electrical energy. Specifically, the heat exchange device 2 includes a heat exchange element 21, which is detachably mounted on one side of the heat exchange section 112. The water inlet of the heat exchange element 21 is connected to a water pump 4 through a water inlet pipe 22, and the water outlet of the heat exchange element 21 is connected to a steam turbine 5 through a water outlet pipe 23. The water pump 4 transfers water to the heat exchange element 21 to exchange heat with the heat transfer medium 10, thereby generating hot steam, which is then supplied to the steam turbine 5 for power generation from the water outlet pipe 23. After the steam turbine 5 generates electricity, or the water discharged from the water outlet pipe 23, it can be pumped back into the heat exchange element 21 for heat exchange.

[0040] The heat exchanger 21 can be configured in various ways, as long as it can achieve heat exchange with the heat exchange section 112.

[0041] In this embodiment, the heat exchanger 21 can be configured as a heat exchange cavity, with one side of the heat exchange cavity fitting snugly against one side of the heat exchange part 112 and being detachably connected, facilitating the replacement of the heat exchanger 21. Alternatively, in other embodiments, one side of the heat exchange cavity can be configured as a concave-convex embedded structure with one side of the heat exchange part 112, ensuring stable installation and detachability while increasing the heat exchange area. The heat exchange area at the upper end of the heat exchange part 112 can be larger (e.g., the concave-convex structure can be denser) to enhance the heat exchange effect (not shown in the figure). In other embodiments, the heat exchanger 21 can also be configured as a meandering heat exchange tube, embedded in one side of the heat exchange part 112. The arrangement of the heat exchange tubes can be optimized according to heat exchange requirements; for example, the heat exchange tubes can be more densely distributed near the upper end of the heat exchange part 112 to increase the heat exchange effect (not shown in the figure).

[0042] The present invention also provides an operating method for the above-mentioned self-circulating tower solar absorber, the steps of which include:

[0043] S1: The heat-absorbing part 111 absorbs solar energy to raise the temperature of the heat-conducting medium 10 located in the heat-absorbing part 111;

[0044] S2: The medium pushing member 12 located in the heat absorption section 111 floats up and pushes the heat-conducting medium 10 located in the heat absorption section 111 from the heat absorption section 111 to the heat exchange section 112.

[0045] S3: Heat exchange section 112 exchanges heat with heat exchange device 2;

[0046] S4: The temperature of the heat transfer medium 10 located in the heat exchange section 112 decreases;

[0047] S5: The medium pushing member 12 located in the heat exchange section 112 sinks down and pushes the heat-conducting medium 10 located in the heat exchange section 112 from the heat exchange section 112 to the heat absorption section 111.

[0048] S6: Cycle through S1 to S5.

[0049] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A self-circulating tower-type solar absorber, characterized in that, include: Heat absorption devices and heat exchange devices; The heat absorption device includes a channel for the flow of a heat-conducting medium, and the channel includes a heat absorption section and a heat exchange section capable of exchanging heat with the heat exchange device. The heat absorption device also includes a medium pushing component; The medium pusher is configured to: float within the heat absorption section, move from the upper end of the heat absorption section to the upper end of the heat exchange section, sink within the heat exchange section, and move from the lower end of the heat exchange section to the lower end of the heat absorption section, so as to push the heat-conducting medium to circulate within the channel; The heat absorption device also includes a heat insulation plate that separates the heat absorption section and the heat exchange section; The heat insulation plate has a first wall surface facing the heat absorption part and a second wall surface facing the heat exchange part; When the medium pushing member is located inside the heat-absorbing part, its outer wall surface is in contact with the first wall surface, and it is also in contact with the inner wall surface of the heat-absorbing part opposite to the first wall surface; When the medium pushing member is located inside the heat exchange section, its outer wall surface is in contact with the second wall surface, and it is also in contact with the inner wall surface of the heat exchange section opposite to the second wall surface; The thermally conductive medium remains in a stable liquid state within the operating temperature range, and the density of the thermally conductive medium changes within the operating temperature range.

2. The self-circulating tower solar absorber according to claim 1, characterized in that, The heat-conducting medium located within the heat-absorbing section has a first temperature; The density of the thermally conductive medium at the first temperature is greater than the density of the medium-driven component at the first temperature.

3. A self-circulating tower solar absorber according to claim 1, characterized in that, The heat-conducting medium located within the heat exchange section has a second temperature; The density of the thermally conductive medium at the second temperature is less than the density of the medium-driven component at the second temperature.

4. A self-circulating tower solar absorber according to claim 1, characterized in that, The medium pushing component is configured as a plurality of hollow spheres or a plurality of hollow cylinders.

5. A self-circulating tower solar absorber according to claim 4, characterized in that, The channel also includes an upper conductive section and a lower conductive section; The upper conductive part connects the heat absorption part and the upper end of the heat exchange part, and the lower conductive part connects the heat absorption part and the lower end of the heat exchange part; The upper conductive portion is provided with upper guide arc segments on both sides near the heat absorption portion and the heat exchange portion; The lower conductive section is provided with lower guide arc segments on both sides near the heat absorption section and the heat exchange section.

6. A self-circulating tower solar absorber according to claim 1, characterized in that, An exhaust valve is also provided at the upper end of the channel.

7. A self-circulating tower solar absorber according to claim 1, characterized in that, The heat exchange device includes a heat exchange element, which is detachably disposed on one side of the heat exchange section; The inlet end of the heat exchanger is connected to a water pump via an inlet pipe, and the outlet end of the heat exchanger is connected to a steam turbine via an outlet pipe.

8. A method for operating a self-circulating tower solar absorber as described in any one of claims 1 to 7, characterized in that, include: The heat-absorbing part absorbs solar energy to raise the temperature of the heat-conducting medium located within the heat-absorbing part; The medium pushing member located in the heat absorption section floats up and pushes the heat-conducting medium located in the heat absorption section from the heat absorption section to the heat exchange section; The heat exchange section exchanges heat with the heat exchange device; The temperature of the heat-conducting medium located in the heat exchange section decreases; The medium pushing member located in the heat exchange section sinks and pushes the heat-conducting medium located in the heat exchange section from the heat exchange section to the heat absorption section.

9. The operating method of the self-circulating tower solar absorber according to claim 8, characterized in that, Also includes: Use an exhaust valve to release steam and reduce the pressure in the channel.

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