Trough solar thermal solid heat storage system and design method thereof

Abstract

The application provides a trough type solar heat collecting and solid heat storing system and a design method thereof, the design method comprising the following steps: S1, obtaining the solar radiation time of each solid heat storing module A1, A2,..., An corresponding to the normal direct radiation intensity of solar energy within a preset time, and obtaining a plurality of groups of radiation time lengths B1, B2,..., Bn; S2, obtaining the use time length of each solid heat storing module according to the plurality of groups of radiation time lengths and through the following formula 1: Cn=B1+B2+...+Bn; and S3, obtaining the number of solid heat storing units under each solid heat storing module according to the use time length of each solid heat storing module and the total amount M of preset solid heat storing units and according to the following formula 2: according to the use time length of the solid heat storing module, setting the corresponding number of solid heat storing units can improve the heat storing efficiency and heat storing capacity of the whole system.

Description

Technical Field

[0001] This invention relates to the field of solar thermal utilization technology, specifically to a design method for a trough-type solar thermal collector solid thermal storage system, and a trough-type solar thermal collector solid thermal storage system designed according to the method. Background Technology

[0002] In parabolic trough solar thermal power generation technology, heat transfer oil is generally used as the heat absorption and transfer medium, and molten salt is used as the heat storage medium. In recent years, due to the rising price of molten salt and the demand for long-term heat storage, the large-scale molten salt energy storage system in parabolic trough technology has led to a significant increase in the initial investment of power plants, seriously affecting their economic viability. Furthermore, due to the high freezing point of molten salt, the cost of anti-condensation during operation has also increased significantly, further reducing the economic viability of long-term molten salt energy storage in parabolic trough technology. Against this backdrop, using solid concrete to replace molten salt as the heat storage medium is a feasible solution. For example, Chinese patents with application numbers 201711296993.1 and 201711296993.1 disclose a solution using solid heat storage to replace heat transfer oil or molten salt for solar thermal power generation, solving the high cost and high operating expenses associated with using molten salt as the heat storage medium in parabolic trough solar thermal power generation. However, due to the inherent characteristics of solid concrete, isothermal stratification inevitably occurs during thermal storage. This means that the temperature rises first near the inlet and falls lower near the outlet, with the temperature of the storage medium decreasing continuously along the flow path. Coupled with the inherent instability and volatility of solar energy, the temperature of the circulating medium entering the storage often fluctuates significantly. This results in the storage area being unable to effectively absorb the temperature of the circulating medium after it enters the conventionally designed storage area. Furthermore, there is a frequent phenomenon where lower-temperature circulating medium enters the higher-temperature storage medium, which not only significantly affects the quality of thermal storage but also reduces the temperature of the steam after heat exchange during heat release, thereby reducing power generation efficiency. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the heat storage area in the prior art cannot effectively absorb the temperature of the circulating medium, thereby providing a design method for a trough solar collector solid thermal storage system, and a trough solar collector solid thermal storage system designed according to the design method.

[0004] According to a first aspect of the present invention, the present invention provides a design method for a parabolic trough solar collector solid thermal storage system, the parabolic trough solar collector solid thermal storage system comprising a plurality of solid thermal storage modules connected in series, each solid thermal storage module comprising a plurality of solid thermal storage units, the design method comprising:

[0005] Step S1: Obtain the solar irradiation time under the solar normal direct radiation intensity for each solid thermal storage module A1, A2...An within a preset time period, and obtain multiple sets of irradiation durations B1, B2...Bn;

[0006] Step S2: Based on multiple irradiation durations, obtain the usage time of each solid thermal storage module using the following formula 1.

[0007] Formula 1: Cn = B1 + B2 + ... + Bn;

[0008] Step S3: Based on the usage time of each solid thermal storage module and the preset total number of solid thermal storage units M, obtain the number of solid thermal storage units under each solid thermal storage module according to the following formula 2.

[0009] Formula 2:

[0010] Optionally, the preset time is one year.

[0011] Optionally, during the solar irradiation time corresponding to each solid thermal storage module, the normal direct solar radiation intensity is greater than 200 W / m. 2 .

[0012] Optionally, at least four of the solid thermal storage modules are connected in series.

[0013] According to a second aspect of the present invention, a trough-type solar thermal collector solid thermal storage system is provided, which is designed by the above-described design method. The trough-type solar thermal collector solid thermal storage system includes multiple solid thermal storage modules, and each solid thermal storage module includes multiple solid thermal storage units.

[0014] Optionally, the system includes a trough-type mirror field system and a circulation pipeline connecting the trough-type mirror field system and the plurality of solid thermal storage modules, wherein the plurality of solid thermal storage modules are connected in series on the circulation pipeline. The system also includes a plurality of branches, which are arranged one-to-one upstream of the plurality of solid thermal storage modules, and each branch is provided with a first switch structure.

[0015] Optionally, a second switch structure is provided on the circulation pipeline upstream of the plurality of branches.

[0016] Optionally, the first and second switch structures are electrically shut-off valves.

[0017] The present invention has the following advantages:

[0018] 1. The design method provided by this invention provides a trough-type solar thermal collector solid thermal storage system comprising multiple solid thermal storage modules, each solid thermal storage module comprising multiple solid thermal storage units, the design method comprising:

[0019] Step S1: Obtain the solar irradiation time under the solar normal direct radiation intensity for each solid thermal storage module A1, A2...An within a preset time period, and obtain multiple sets of irradiation durations B1, B2...Bn;

[0020] Step S2: Based on multiple irradiation durations, obtain the usage duration of each solid thermal storage module using the following formula 1: Formula 1: Cn=B1+B2+…+Bn;

[0021] Step S3: Based on the usage time of each solid thermal storage module and the preset total number of solid thermal storage units M, obtain the number of solid thermal storage units under each solid thermal storage module according to the following formula 2: Formula 2:

[0022] As described in the background section, the heat collection of a parabolic trough solar system is affected by the intensity of the solar normal radiation. Therefore, it is necessary to set solid thermal storage modules A1, A2...An corresponding to different radiation intensities based on the solar normal radiation intensity. Then, the solar irradiation time corresponding to different radiation intensities is determined within a predetermined time, resulting in multiple irradiation durations B1, B2...Bn. The design temperatures of the multiple solid thermal storage modules decrease sequentially, which means that when the heat exchange medium temperature meets the design temperature of any solid thermal storage module, other solid thermal storage modules with lower design temperatures can be used. Therefore, the usage time of each solid thermal storage module can be calculated according to Formula 1.

[0023] After obtaining the usage time of each solid thermal energy storage module, the number of solid thermal energy storage units in each module can be determined by multiplying the ratio of each module's usage time to the total usage time of all modules by the total number of solid thermal energy storage units. Therefore, the design method of this invention not only sets the solid thermal energy storage modules to the corresponding design temperature based on the solar normal radiation intensity, but also determines the number of solid thermal energy storage units based on the usage time of each module. Thus, the design method of this invention can reduce the impact of changes in solar normal radiation intensity on the thermal storage temperature of the solid thermal energy storage module, and also improve the heat exchange efficiency of the heat exchange medium by using solid thermal energy storage modules with different numbers of solid thermal energy storage units. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a flowchart of the design method of the trough-type solar thermal collector solid thermal storage system in Embodiments 1 and 2 of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of the trough-type solar thermal collector solid thermal storage system in Embodiment 3 of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Trough-type mirror field system; 11. Heat collector outlet; 12. Heat collector inlet; 13. Trough-type mirror field collector; 2. Circulation pipeline; 31. First branch pipe; 32. Second branch pipe; 321. First connection node; 322. Second connection node; 41. First switch structure; 42. Second switch structure; A1. First solid thermal storage module; A2. Second solid thermal storage module; An. nth solid thermal storage module; 5. Circulation pump. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] 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 according to the specific circumstances.

[0032] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Example 1

[0034] refer to Figure 1 This embodiment provides a design method for a parabolic trough solar collector solid thermal storage system. The parabolic trough solar collector solid thermal storage system includes multiple solid thermal storage modules connected in series. The design temperatures of the multiple solid thermal storage modules decrease sequentially. Each solid thermal storage module includes multiple solid thermal storage units. The design method includes:

[0035] Step S1: Obtain the solar irradiation time under the solar normal direct radiation intensity for each solid thermal storage module A1, A2...An within a preset time period, and obtain multiple sets of irradiation durations B1, B2...Bn.

[0036] Specifically, the preset time period can be one year. A year allows for statistical analysis of the distribution of solar normal radiation and facilitates prediction of solar energy distribution for the following year. The design temperatures of multiple solid thermal storage modules are defined as K1, K2…Kn, where K1 to Kn decrease sequentially. Based on the design temperature, the names of the multiple solid thermal storage modules are defined as A1, A2…An.

[0037] Because the temperature of the heat exchange medium flowing out of the trough mirror field heat collection system varies under different solar normal direct radiation intensities, the heat exchange medium at that temperature can be selected to enter the solid thermal storage module at the corresponding design temperature for heat storage. This prevents the low-temperature heat exchange medium from entering the high-temperature solid thermal storage module and affecting its original heat storage temperature. Therefore, the irradiation time under a specific solar normal direct radiation intensity corresponds to the usage time of the solid thermal storage module at a specific design temperature. Thus, it is necessary to first determine the corresponding time for the solar normal direct radiation intensity and obtain multiple sets of irradiation durations under different solar normal direct radiation intensities. These multiple sets of different irradiation durations are defined as B1, B2, ..., Bn.

[0038] Specifically, during the solar irradiance period corresponding to each solid thermal storage module, the normal solar radiation intensity was greater than 200 W / m. 2 .

[0039] Specifically, at least four solid thermal storage modules connected in series should be installed.

[0040] Taking Gansu Province as an example, a parabolic trough solar thermal collector and solid-state thermal storage system can be installed in Gansu. Five solid-state thermal storage modules can be installed in the region: module A1, module A2, module A3, module A4, and module A5. The design temperature for module A1 is 390℃, for module A2 it is 380℃, for module A3 it is 370℃, for module A4 it is 360℃, and for module A5 it is 350℃.

[0041] Based on this, the range of solar normal direct radiation values ​​corresponding to each solid thermal energy storage module can be determined. The first solid thermal energy storage module A1 corresponds to a solar normal direct radiation value greater than 1000 W / m. 2 The solar normal radiation value corresponding to the second solid thermal storage module A2 is in the range of 800 to 1000 W / m. 2 The third solid thermal storage module A3 corresponds to a solar normal direct radiation value ranging from 600 to 800 W / m². 2 The solar normal radiation value range corresponding to the fourth solid thermal storage module A4 is 400 to 600 W / m. 2 The solar normal radiation value range for the fifth solid thermal storage module A5 is 200 to 300 W / m². 2 Furthermore, the time corresponding to the representative year of this region and the five sets of solar normal direct radiation intensity ranges are shown in Table 1 below:

[0042] serial number <![CDATA[Solar direct normal irradiance intensity range (W / m 2 )]]> Bn irradiation duration (hours) 1 >1000 195 2 800～1000 978 3 600～800 783 4 400～600 616 5 200～400 642 total 3214

[0043] Table 1

[0044] According to Table 1, the above five sets of solar normal direct radiation intensity ranges all meet the operating requirements of the parabolic trough solar thermal collector system in this region. The unit of solar normal direct radiation intensity range is watts per square meter, but other units used in the solar energy field for recording solar normal direct radiation intensity ranges can also be used. Each of the five sets of solar normal direct radiation intensities has a corresponding irradiation time: B1 = 195 hours, B2 = 978 hours, B3 = 783 hours, B4 = 616 hours, and B5 = 642 hours.

[0045] Step S2: Based on multiple irradiation durations, obtain the usage duration of each solid thermal storage module using the following formula 1: Formula 1: Cn=B1+B2+…+Bn.

[0046] Specifically, the intensity of solar normal direct radiation directly affects the temperature of the heat exchange medium flowing out of the trough mirror field system. The heat stored in the corresponding solid thermal storage module needs to be determined based on the temperature of the heat exchange medium. Therefore, the irradiation time within a specific range of solar normal direct radiation intensity corresponds to the solid thermal storage module at a specific design temperature. Compared with existing technologies, this invention considers a more reasonable setting for the solid thermal storage module, thus further determining the usage time of the solid thermal storage module. The usage time of the solid thermal storage module is related to the temperature of the heat exchange medium. Specifically, when the temperature of the heat exchange medium is higher than the design temperature of the solid thermal storage module, the solid thermal storage module can exchange heat with the heat exchange medium at the current temperature, and the time spent exchanging heat with the medium at that temperature is accumulated to obtain the corresponding usage time of the solid thermal storage module.

[0047] Continuing with the previous example, based on the irradiation time of each solar normal direct radiation range mentioned above and the public...

[0048] Equation 1 yields the following Table 2:

[0049]

[0050] Table 2

[0051] According to Table 2, the usage time of the first solid thermal energy storage module A1 is C1, C1 = 195 hours; the usage time of the second solid thermal energy storage module A2 is C2, C2 = 1173 hours; the usage time of the third solid thermal energy storage module A3 is C3, C3 = 1956 hours; the usage time of the fourth solid thermal energy storage module A4 is C4, C4 = 2572 hours; and the usage time of the fifth solid thermal energy storage module A5 is C5, C5 = 3214 hours.

[0052] Step S3: Based on the usage time of each solid thermal storage module and the preset total number of solid thermal storage units M, obtain the number of solid thermal storage units under each solid thermal storage module according to the following formula 2: Formula 2:

[0053] Specifically, the total number M of the preset solid thermal storage units can be determined according to actual needs, for example, based on the size of the trough-type mirror field collector solid thermal storage system. Di is the number of solid thermal storage units in the i-th solid thermal storage module.

[0054] Following the previous example, based on Formula 2, the total number of solid thermal storage units, and the usage time of each solid thermal storage module determined above, the number of solid thermal storage modules corresponding to each solid thermal storage module is obtained. The total number of solid thermal storage units is 2000. The first solid thermal storage module A1 contains 42 solid thermal storage units; the second solid thermal storage module A2 contains 258 solid thermal storage units; the third solid thermal storage module A3 contains 429 solid thermal storage units; the fourth solid thermal storage module A4 contains 565 solid thermal storage units; and the fifth solid thermal storage module A5 contains 706 solid thermal storage units.

[0055] Based on this, the present invention designs solid thermal storage modules with different design temperatures, and determines the corresponding range of solar normal direct radiation values ​​according to the design temperature of each solid thermal storage module. Then, combined with the solar normal direct radiation conditions of a representative region, the corresponding irradiation time is determined. Subsequently, the usage time of each solid thermal storage module is determined according to the irradiation time, wherein the usage time of the solid thermal storage module is the time that meets the design temperature of the solid thermal storage module. Finally, the number of solid thermal storage units corresponding to each solid thermal storage module is determined according to the usage time of each solid thermal storage module and the total number of solid thermal storage units. This allows for a more reasonable allocation of solid thermal storage units, maximizing the utilization of each solid thermal storage module and improving the thermal storage capacity and efficiency of the entire solid thermal storage system.

[0056] Example 2

[0057] This embodiment uses the same method and steps as Embodiment 1 to obtain the number of solid thermal storage units in each solid thermal storage module. The meanings of the terms in each method and step are the same, and will not be repeated in this embodiment. The differences between this embodiment and Embodiment 1 will be explained in detail below.

[0058] Step S1: Obtain the solar irradiation time under the solar normal direct radiation intensity for each solid thermal storage module A1, A2...An within a preset time period, and obtain multiple sets of irradiation durations B1, B2...Bn.

[0059] Specifically, the preset time in this embodiment can be one year. One year can be used to statistically analyze the distribution of solar normal radiation and to make it easier to predict the distribution of solar energy in the following year.

[0060] Taking Xinjiang as an example, a parabolic trough solar collector solid thermal storage system can be installed in Xinjiang, with ten solid thermal storage modules installed in the region, namely, the first solid thermal storage module A1, the second solid thermal storage module A2, the third solid thermal storage module A3, the fourth solid thermal storage module A4, the fifth solid thermal storage module A5, the sixth solid thermal storage module A6, the seventh solid thermal storage module A7, the eighth solid thermal storage module A8, the ninth solid thermal storage module A9, and the tenth solid thermal storage module A10. The design temperature of the first solid thermal energy storage module A1 is 550℃, the design temperature of the second solid thermal energy storage module A2 is 540℃, the design temperature of the third solid thermal energy storage module A3 is 530℃, the design temperature of the fourth solid thermal energy storage module A4 is 520℃, the design temperature of the fifth solid thermal energy storage module A5 is 510℃, the design temperature of the sixth solid thermal energy storage module A6 is 500℃, the design temperature of the seventh solid thermal energy storage module A7 is 480℃, the design temperature of the eighth solid thermal energy storage module A8 is 460℃, the design temperature of the ninth solid thermal energy storage module A9 is 440℃, and the design temperature of the tenth solid thermal energy storage module A10 is 420℃.

[0061] Based on this, the range of solar normal direct radiation values ​​corresponding to each solid thermal energy storage module can be determined. The first solid thermal energy storage module A1 corresponds to a solar normal direct radiation value greater than 1100 W / m². 2 The solar normal radiation value corresponding to the second solid thermal storage module A2 ranges from 1000 to 1100 W / m. 2 The third solid thermal storage module A3 corresponds to a solar normal radiation value ranging from 900 to 1000 W / m². 2 The solar normal radiation value range corresponding to the fourth solid thermal storage module A4 is 800 to 900 W / m². 2 The solar normal radiation value corresponding to the fifth solid thermal storage module A5 is 700 to 800 W / m². 2 The sixth solid thermal storage module A6 corresponds to a solar normal direct radiation value range of 600 to 700 W / m². 2 The solar normal radiation value range corresponding to the seventh solid thermal storage module A7 is 500 to 600 W / m. 2 The solar normal radiation value range corresponding to the eighth solid thermal storage module A8 is 400 to 500 W / m. 2 The solar normal radiation value range corresponding to the ninth solid thermal storage module A9 is 300 to 400 W / m². 2 The solar normal radiation value range corresponding to the tenth solid thermal storage module A10 is 200 to 300 W / m. 2 Furthermore, the representative year for this region corresponds to the time range of 10 sets of solar normal direct radiation intensity, as shown in Table 3 below:

[0062] serial number <![CDATA[Normal direct solar radiation intensity range (W / m 2 )]]> Bn irradiation duration (hours) 1 >1100 18 2 1000～1100 99 3 900～1000 297 4 800～900 491 5 700～800 502 6 600～700 383 7 500～600 325 8 400～500 272 9 300～400 314 10 200～300 336 total 3037

[0063] Table 3

[0064] According to Table 3, the above 10 sets of solar normal direct radiation intensity ranges all meet the operating requirements of the parabolic trough solar thermal collector system in this region. The unit of solar normal direct radiation intensity range is watts per square meter, but other units used in the solar energy field for recording solar normal direct radiation intensity ranges can also be used. Each of the 10 sets of solar normal direct radiation intensities has a corresponding irradiation time: B1 = 18 hours, B2 = 99 hours, B3 = 297 hours, B4 = 491 hours, B5 = 502 hours, B6 = 383 hours, B7 = 325 hours, B8 = 272 hours, B9 = 314 hours, and B10 = 336 hours.

[0065] Step S2: Based on multiple irradiation durations, obtain the usage duration of each solid thermal storage module using the following formula 1: Formula 1: Cn=B1+B2+…+Bn.

[0066] Continuing with the previous example, based on the irradiation time of each solar normal direct radiation range mentioned above and the public...

[0067] Equation 1 yields the following Table 4:

[0068]

[0069] Table 4

[0070] According to Table 4, the usage time of the first solid thermal energy storage module A1 is C1, C1 = 18 hours; the usage time of the second solid thermal energy storage module A2 is C2, C2 = 117 hours; the usage time of the third solid thermal energy storage module A3 is C3, C3 = 414 hours; the usage time of the fourth solid thermal energy storage module A4 is C4, C4 = 905 hours; the usage time of the fifth solid thermal energy storage module A5 is C5, C5 = 1407 hours; the usage time of the sixth solid thermal energy storage module A6 is C6, C6 = 1790 hours; the usage time of the seventh solid thermal energy storage module A7 is C7, C7 = 2115 hours; the usage time of the eighth solid thermal energy storage module A8 is C8, C8 = 2387 hours; the usage time of the ninth solid thermal energy storage module A9 is C9, C9 = 2701 hours; and the usage time of the tenth solid thermal energy storage module A10 is C10, C10 = 3037 hours.

[0071] Step S3: Based on the usage time of each solid thermal storage module and the preset total number of solid thermal storage units M, obtain the number of solid thermal storage units under each solid thermal storage module according to the following formula 2: Formula 2:

[0072] Specifically, the total number M of the preset solid thermal storage units can be determined according to actual needs, for example, based on the size of the trough-type mirror field collector solid thermal storage system. Di is the number of solid thermal storage units in the i-th solid thermal storage module.

[0073] Following the previous example, based on Formula 2, the total number of solid thermal storage units, and the usage time of each solid thermal storage module determined above, we can obtain the number of solid thermal storage modules corresponding to each solid thermal storage module. The total number of solid thermal energy storage units is 8000. The first solid thermal energy storage module A1 contains 10 solid thermal energy storage units; the second solid thermal energy storage module A2 contains 64 solid thermal energy storage units; the third solid thermal energy storage module A3 contains 223 solid thermal energy storage units; the fourth solid thermal energy storage module A4 contains 488 solid thermal energy storage units; the fifth solid thermal energy storage module A5 contains 755 solid thermal energy storage units; the sixth solid thermal energy storage module A6 contains 961 solid thermal energy storage units; the seventh solid thermal energy storage module A7 contains 1135 solid thermal energy storage units; the eighth solid thermal energy storage module A8 contains 1282 solid thermal energy storage units; the ninth solid thermal energy storage module A9 contains 1450 solid thermal energy storage units; and the tenth solid thermal energy storage module A10 contains 1632 solid thermal energy storage units.

[0074] Based on this, the present invention designs solid thermal storage modules with different design temperatures, and determines the corresponding range of solar normal direct radiation values ​​according to the design temperature of each solid thermal storage module. Then, combined with the solar normal direct radiation conditions of a representative region, the corresponding irradiation time is determined. Subsequently, the usage time of each solid thermal storage module is determined according to the irradiation time, wherein the usage time of the solid thermal storage module is the time that meets the design temperature of the solid thermal storage module. Finally, the number of solid thermal storage units corresponding to each solid thermal storage module is determined according to the usage time of each solid thermal storage module and the total number of solid thermal storage units. This allows for a more reasonable allocation of solid thermal storage units, maximizing the utilization of each solid thermal storage module and improving the thermal storage capacity and efficiency of the entire solid thermal storage system.

[0075] It should be noted that the specific data in the above embodiments are only for clearly illustrating the specific implementation of the design method provided by the present invention. Different basic data can also be reasonably set according to actual conditions, such as natural environmental factors, solid thermal storage system size factors, etc., including but not limited to the design temperature of the solid thermal storage module, the range of solar normal direct radiation value, and the total number of solid thermal storage units.

[0076] Example 3

[0077] This embodiment provides a trough-type solar thermal collector solid thermal storage system, which is designed using the design method of Embodiment 1 above. The trough-type solar thermal collector solid thermal storage system of this embodiment has multiple solid thermal storage modules, and the design temperature of the multiple solid thermal storage modules decreases sequentially. Each solid thermal storage module includes multiple solid thermal storage units.

[0078] Specifically, such as Figure 2 As shown, the trough-type solar thermal collector solid-state thermal storage system includes a first solid-state thermal storage module A1, a second solid-state thermal storage module A2, ..., an nth solid-state thermal storage module An. The design temperatures of the first solid-state thermal storage module A1 to the nth solid-state thermal storage module An decrease sequentially, and each solid-state thermal storage module includes multiple solid-state thermal storage units. The number of solid-state thermal storage units in each solid-state thermal storage module in this embodiment can be calculated through the design steps described above, and will not be illustrated further here.

[0079] Optionally, the solid thermal storage unit consists of a solid thermal storage medium cast into a certain shape and several parallel steel pipes embedded therein. The steel pipes are arranged in a serpentine pattern within the solid thermal storage medium, with manifolds at both the inlet and outlet. The heat exchange medium enters each steel pipe from the inlet manifold, and the steel pipes transfer heat to the solid thermal storage medium through thermal radiation, storing the heat before flowing out through the outlet manifold.

[0080] Solid thermal storage media have excellent heat preservation properties and, compared to commonly used thermal storage media in solar power generation such as water, thermal oil, and molten salt, do not solidify at low temperatures, thus eliminating the need to maintain a minimum internal temperature in low-temperature environments. Furthermore, no additional water pumps, thermal oil pumps, or molten salt pumps are required in each thermal storage unit to maintain the flow of the thermal storage media, resulting in low operating costs. Solid thermal storage media can be a mixture of one or more of basalt, andesite, diabase, granite, and quartzite as the main medium, with the addition of various modified mineral additives.

[0081] In one embodiment of this invention, the trough solar thermal collector solid thermal storage system includes a trough mirror field system 1 and a circulation pipeline 2 connecting the trough mirror field system 1 and multiple solid thermal storage modules. The multiple solid thermal storage modules are connected in series on the circulation pipeline 2. The system also includes multiple branches, which are arranged one-to-one upstream of the multiple solid thermal storage modules. Each branch is equipped with a first switch structure 41.

[0082] Specifically, refer to Figure 2The trough mirror field system 1 includes a heat collection inlet 12 for the inflow of heat exchange medium and a heat collection outlet 11 for the outflow of heat exchange medium, as well as multiple trough mirror field collectors 13 connected in parallel between the heat collection inlet 12 and the heat collection outlet 11. When the trough mirror field subsystem is in operation, the low-temperature heat exchange medium enters the trough mirror field system 1 through the heat collection inlet 12, and after heat exchange by the multiple trough mirror field collectors 13, it becomes a high-temperature heat exchange medium and flows out from the heat collection outlet 11.

[0083] The parabolic trough solar collector 13 includes at least a heat collection tube and a parabolic reflector. During operation, the heat collection tube supplies the heat exchange medium, and the parabolic reflector reflects and focuses sunlight onto the heat collection tube to heat the heat exchange medium, thereby converting solar energy into thermal energy. Those skilled in the art are familiar with the specific structure and operation of parabolic trough solar collectors; the above is merely an example and will not be described in detail here. The heat exchange medium can be one of heat transfer oil, molten salt, high-pressure water, or steam.

[0084] The circulation pipeline 2 is connected in sequence to the heat collection outlet 11 of the trough-type mirror field system 1, multiple solid heat storage modules connected in series, and the heat collection inlet 12. The section of the circulation pipeline 2 located upstream of the first solid heat storage module A1 can be referred to as the first branch pipe 31.

[0085] Taking the second solid thermal energy storage module A2 as an example, the branch pipe connected upstream of the second solid thermal energy storage module is designated as the second branch pipe 32. One end of the second branch pipe 32 is connected to the first branch pipe 31 to form a first connection node 321, which is located between the first solid thermal energy storage module A1 and the heat collection outlet 11. The other end is connected to the circulation pipeline between the first solid thermal energy storage module A1 and the second solid thermal energy storage module A2, forming a second connection node 322. The first switch structure 41 of the first branch pipe 31 is located between the first connection node 321 and the first solid thermal energy storage module A1, and the first switch structure 41 of the second branch pipe 32 is located between the first connection node 321 and the second connection node 322. The branch pipes on the third solid thermal energy storage module and subsequent solid thermal energy storage modules can be set up in the same way as described above, and will not be listed here.

[0086] In use, the heat exchange medium flowing out of the heat collector outlet 11 can be controlled to enter the corresponding solid heat storage module by selecting to open the first switch structure 41 of the corresponding branch pipe. Since multiple solid heat storage modules are connected in series, the heat exchange medium entering any solid heat storage module will pass through the subsequent solid heat storage modules in sequence and then flow to the heat collector inlet 12. For example, when the temperature of the heat exchange medium flowing out from the heat collector outlet 11 is higher than or equal to the design temperature of the first solid thermal storage module A1, the first switch structure 41 of the first branch pipe 31 is opened, and the first switch structure 41 of the other branches is closed. The heat exchange medium can enter the first solid thermal storage module A1 through the first branch pipe 31 for heat exchange, and then pass through all subsequent solid thermal storage modules for heat exchange in sequence, before flowing to the heat collector inlet 12. When the temperature of the heat exchange medium flowing out from the heat collector outlet 11 is lower than the design temperature of the first solid thermal storage module A1 but higher than the design temperature of the second solid thermal storage module A2, the first switch structure 41 of the second branch pipe 32 is opened, and the first switch structure 41 of the other branches is closed. The heat exchange medium enters the second solid thermal storage module A2 through the second branch pipe 32 for heat exchange, and then passes through all subsequent solid thermal storage modules for heat exchange in sequence, before flowing to the heat collector inlet 12.

[0087] The above method ensures that the heat exchange medium enters the solid thermal storage module at the corresponding design temperature for heat exchange, preventing the low-temperature heat exchange medium from entering the high-temperature solid thermal storage module and disrupting the original thermal storage temperature of the solid thermal storage module.

[0088] Optionally, a second switch structure 42 is provided upstream of multiple branches on the circulation pipeline 2. The second switch structure 42 is located between the heat collector outlet 11 and the first connection node 321. The second switch structure 42 can control the opening or closing of the entire circulation pipeline.

[0089] In one specific embodiment of this example, the first switch structure 41 and the second switch structure 42 can be electrically shut-off valves, or they can be shut-off valves, regulating valves, check valves, etc. commonly used in the field of solar energy utilization.

[0090] Optionally, a circulation pump 5 is installed on the circulation pipeline 2, which can provide power for the flow of the heat exchange medium in the circulation pipeline.

[0091] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A design method for a trough-type solar thermal collector and solid thermal storage system, characterized in that, The trough-type solar thermal collector solid-state thermal storage system includes multiple solid-state thermal storage modules connected in series. The design temperatures of the multiple solid-state thermal storage modules decrease sequentially. Each solid-state thermal storage module includes multiple solid-state thermal storage units. The design method includes: Step S1: Obtain the solar irradiation time under the solar normal direct radiation intensity for each solid thermal storage module A1, A2...An within a preset time period, and obtain multiple sets of irradiation durations B1, B2...Bn; Step S2: Based on multiple irradiation durations, obtain the usage duration Cj of each solid thermal storage module using the following formula 1. Official 1: ; Where Cj is the usage time of the j-th solid thermal storage module among multiple solid thermal storage modules, 0<j≤n; Step S3: Based on the usage time of each solid thermal storage module and the preset total number of solid thermal storage units M, obtain the number of solid thermal storage units Di under each solid thermal storage module according to the following formula 2. Official 2: ; Where Di represents the number of solid thermal storage units in the i-th solid thermal storage module among multiple solid thermal storage modules.

2. The design method according to claim 1, characterized in that, The preset time is one year.

3. The design method according to claim 1, characterized in that, During the solar irradiation time corresponding to each solid thermal storage module, the normal direct solar radiation intensity is greater than 200. .

4. The design method according to claim 1, characterized in that, At least four of the solid thermal storage modules are connected in series.

5. A trough-type solar thermal collector solid-state thermal storage system, designed using the design method described in any one of claims 1 to 4, characterized in that, The parabolic trough solar collector solid thermal storage system includes multiple solid thermal storage modules, the design temperatures of which decrease sequentially, and each solid thermal storage module includes multiple solid thermal storage units.

6. The trough-type solar thermal collector and solid thermal storage system according to claim 5, characterized in that, It includes a trough-type mirror field system (1) and a circulation pipeline (2) connecting the trough-type mirror field system (1) and the multiple solid thermal storage modules. The multiple solid thermal storage modules are connected in series on the circulation pipeline (2). It also includes multiple branches, which are arranged one-to-one upstream of the multiple solid thermal storage modules. Each branch is provided with a first switch structure (41).

7. The trough-type solar thermal collector and solid thermal storage system according to claim 6, characterized in that, A second switch structure (42) is provided on the circulation pipeline (2) at the upstream position of the multiple branches.

8. The trough-type solar thermal collector and solid thermal storage system according to claim 7, characterized in that, The first switch structure (41) and the second switch structure (42) are electrically shut-off valves.

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