Wide-adaptability microgroove type solar heat collection system

Abstract

The invention provides a wide-adaptability microgroove type solar heat collection system, and belongs to the technical field of solar heat utilization, the wide-adaptability microgroove type solar heat collection system comprises a reflection condenser assembly, a module linkage rod, a heat exchanger, a header and a support adjusting mechanism, the support adjusting mechanism comprises an eccentric self-locking manual adjusting system and a thermal driving passive tracking system, reflection condenser assemblies are arranged at the two ends of the header, each reflection condenser assembly comprises a reflection condenser and a heat collecting pipe, the heat exchangers are arranged in the header, the reflection condenser assemblies are connected through module linkage rods, and thermally-driven passive tracking systems are arranged at the two ends of each reflection condenser assembly. The eccentric self-locking manual adjusting system comprises an area linkage adjusting mechanism. By the adoption of the wide-adaptability micro-groove type solar heat collection system, the technical contradiction that a traditional groove type system is high in cost and an existing small system is low in efficiency is solved.

Description

Technical Field

[0001] This invention relates to the field of solar thermal utilization technology, and in particular to a wide-adaptability microtrough solar thermal collector system. Background Technology

[0002] Medium-temperature solar thermal utilization has broad application prospects in industrial and commercial sectors and has become an important development direction for new energy utilization. However, the existing technologies related to medium-temperature solar thermal utilization have significant technical contradictions and application pain points, which seriously restrict the large-scale promotion in this field.

[0003] Traditional parabolic trough solar thermal systems employ a high-precision dual-axis tracking structure paired with metal-glass collector tubes. This system has a complex overall design and requires extremely high precision in its components, resulting in high manufacturing costs. Furthermore, the complex structure significantly increases the difficulty and cost of subsequent operation and maintenance, making it difficult to meet the low-cost application requirements of distributed industrial and commercial applications. Existing small-scale parabolic trough solar products or fixed collector systems suffer from low concentration ratios and high heat losses. In the medium-temperature application range of 50℃ to 300℃, their efficiency degrades severely, failing to meet the efficiency requirements for medium-temperature heat utilization in industrial and commercial applications.

[0004] The characteristics of solar altitude angle variation vary significantly across different latitudes, but existing solar thermal collectors are not designed with this characteristic in mind. This results in inconsistent heat collection performance of the same product across different latitudes, leading to poor adaptability. Current technologies struggle to effectively address stable and efficient heat collection within a 30° range of solar altitude angle variation while maintaining low cost. Using a high-precision tracking system is prohibitively expensive and impractical; a fixed system suffers efficiency losses exceeding 40% within this range; and reducing the aperture size to accommodate angle variations compromises the concentration ratio and reduces system efficiency at high temperatures, creating a dilemma in technology selection.

[0005] In summary, there is an urgent need for an innovative technological solution in the field of medium-temperature solar energy utilization that can effectively adapt to different latitude regions without significantly increasing costs, especially maintaining stable and efficient heat collection performance within a 30° range of solar altitude angle variation, breaking through the technical bottleneck between low cost and high efficiency, and achieving a technological and economic breakthrough in medium-temperature solar energy utilization. Summary of the Invention

[0006] The purpose of this invention is to provide a widely adaptable microtrough solar thermal collector system that resolves the technical contradiction between the high cost of traditional trough systems and the low efficiency of existing small systems.

[0007] To achieve the above objectives, the present invention provides a wide-adaptability microtrough solar thermal collector system, including a reflective concentrator assembly, a modular linkage rod, a heat exchanger, a header, and a support and adjustment mechanism. The support and adjustment mechanism includes an eccentric self-locking manual adjustment system and a heat-driven passive tracking system. Reflective concentrator assemblies are provided at both ends of the header. Each reflective concentrator assembly includes a reflective concentrator and a heat collection tube. The heat exchanger is located inside the header. The reflective concentrator assemblies are connected to each other via the modular linkage rod. The heat-driven passive tracking system is provided at both ends of the reflective concentrator assemblies. The eccentric self-locking manual adjustment system includes a regional linkage adjustment mechanism.

[0008] Preferably, the reflective condenser is provided with reflective condenser shaping ribs at both ends. The reflective condenser shaping ribs include an upper reflective condenser rib and a lower reflective condenser rib, and the reflective condenser is fixed between the upper reflective condenser rib and the lower reflective condenser rib.

[0009] Preferably, the heat-driven passive tracking system includes an angle positioning gear, a passive tracking ring inside the angle positioning gear, a positioning pulley inside the passive tracking ring, a slot on the passive tracking ring, a lens frame adjusting rod, a push plate and a thermal element inside the slot, a push plate below the lens frame adjusting rod, a thermal element connected to the light-facing surface of the push plate, the push plate and the slot being slidably connected, and a heat collection tube above the reflective condenser lens assembly, with both ends of the heat collection tube fixed to the positioning pulley.

[0010] Preferably, the thermal element is a bimetallic strip or a hydraulic / pneumatic push rod. The bimetallic strip includes a large / small expansion metal strip and a hydraulic / pneumatic expansion metal strip. The hydraulic / pneumatic push rod is filled with a hydraulic / pneumatic medium. The outer surface of the thermal drive element can be coated with a heat-absorbing film.

[0011] Preferably, the heat collection tube includes an inner wall and an outer wall, and a heat exchanger is provided inside the heat collection tube. The heat exchanger includes an inner sleeve and an outer sleeve. Radial fins of the heat exchanger are provided between the outer sleeve and the inner wall of the heat collection tube, and a spiral flow channel is provided on the inner sleeve of the heat exchange tube.

[0012] Preferably, the header includes an inner header pipe and an outer header pipe, with the square of the inner header pipe diameter being half the square of the outer header pipe diameter; the first end of the heat exchanger outer sleeve is connected to the outer header pipe, the end of the heat exchanger outer sleeve is closed, the first end of the heat exchanger inner sleeve is connected to the inner header pipe, the end of the heat exchanger inner sleeve is open, and the square of the inner sleeve diameter is half the square of the outer sleeve diameter.

[0013] Preferably, the regional linkage adjustment mechanism includes regional linkage support frames and linkage rods at both ends. A manual adjustment disc is provided inside the regional linkage support frame. The linkage rod is fixedly connected to the manual adjustment disc. A threaded roller is provided on the linkage rod. The threaded roller is meshed with an angle positioning gear. A regional support fixing disc is provided inside the manual adjustment disc. The regional linkage support frame is slidably connected to the manual adjustment disc through the regional support fixing disc.

[0014] Preferably, an eccentric wheel is provided below the area bracket fixing plate, and an eccentric self-locking handle is provided on the eccentric wheel. An arc-shaped slot plate is provided below the manual adjustment plate at a position corresponding to the eccentric wheel. A limit mark is provided on the arc-shaped slot plate, and an arc-shaped limit indicator slot is provided on the outer side of the arc-shaped slot plate.

[0015] Preferably, the reflecting concentrator adopts a three-segment composite curve design, including: a pure parabolic segment with a central region of 60% arc length, a parabolic and involute mixed segment with a transition region of 20% arc length, and an involute-dominant segment with an edge region of 20% arc length; the boundary angle of the reflecting concentrator is 90°±25°, and the opening width A and the outer diameter D of the heat collection tube satisfy 2.5<A / (πD / 2)<4.0.

[0016] Preferably, the reflecting condenser is made of glass, metal, or plastic, and the upper and lower retaining ribs of the reflecting condenser adopt a three-segment composite curve design.

[0017] Therefore, the present invention employs the above-mentioned wide-adaptability microtrough solar thermal collector system, and the technical effects are as follows: 1. Overcoming the technical contradiction between cost and efficiency: Achieving heat collection efficiency close to that of a high-precision tracking system at a cost close to that of a fixed system, breaking through the long-standing technical bottleneck in the field of medium-temperature solar energy utilization.

[0018] 2. Improved solar heat collection stability under varying solar altitude angles: Within a 30° range of solar altitude angle variation, the effective concentration ratio (equalized type) is no less than 3.0, and the time integral performance is improved by more than 30% and about 40% compared to pure parabolic concentrators and traditional fixed concentrators, respectively, solving the problem of sharp efficiency decay under angle changes.

[0019] 3. Achieve energy-free automatic tracking and convenient manual adjustment with low workload: The heat-driven passive tracking system requires no external energy source or control circuit, automatically responds within 50-150℃, and has a tracking accuracy within ±3°; the eccentric self-locking manual adjustment system supports synchronous adjustment of the entire row of modules, which can be completed by a single person in 5-10 minutes, with a synchronization accuracy of ±0.5°, and adapts to intraday and seasonal changes in solar altitude angle.

[0020] 4. Significantly improves heat exchange efficiency and reduces flow resistance: The spiral double-layer tube heat exchanger built into the heat collector tube has a heat transfer coefficient that is more than 35% higher than that of the traditional U-tube and a flow resistance that is more than 90% lower, thus enhancing heat transfer efficiency.

[0021] 5. It has the ability to adapt to all latitudes: It can match the light concentration ratio of 2.5-4.0 and the receiving angle of 25°-38° according to the solar altitude angle characteristics of different latitudes. It also provides three types of parameter configurations: economic, balanced and high performance, to ensure the optimal heat collection performance in different regions around the world. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a wide-adaptability microgroove solar thermal collector system according to the present invention; Figure 2 This is a cross-sectional view of the overall structure of a wide-adaptability microtrough solar thermal collector system according to the present invention; Figure 3 This is a schematic diagram of the reflective concentrator assembly of the present invention; Figure 4 This is a schematic diagram of the microgroove support adjustment mechanism of the present invention; Figure 5 This is a schematic diagram of the thermally driven passive tracking system of the present invention; Figure 6 This is a schematic diagram of the thermal drive element of the present invention; (a) is a bimetallic strip; (b) is a hydraulic / pneumatic expansion metal strip; (c) is a hydraulic / pneumatic push rod; Figure 7 This is a schematic diagram of the heat collection tube structure of the present invention; Figure 8 This is a side view of the heat exchanger structure of the present invention; Figure 9 This is a schematic diagram of the regional linkage adjustment mechanism of the present invention; Figure 10 This is a schematic diagram of the manual adjustment disc structure of the present invention; Figure 11 This is a schematic diagram of the manual adjustment and loosening state of the eccentric self-locking mechanism of the present invention; Figure 12 This is a schematic diagram of the manual adjustment and locking state of the eccentric self-locking mechanism of the present invention; Figure 13 This is a schematic diagram showing the installation angle of the reflective concentrator mirror of the present invention; Figure 14 This is a schematic diagram of an embodiment of the optical system of the present invention.

[0023] Figure Labels 1. Reflecting condenser lens assembly; 2. Module linkage rod; 3. Heat exchanger; 4. Manifold; 5. Eccentric self-locking manual adjustment system; 6. Regional linkage adjustment mechanism; 7. Inner pipe of manifold; 8. Outer pipe of manifold; 9. Heat collector tube; 10. Inner wall of heat collector tube; 11. Outer wall of heat collector tube; 12. Radial fins of heat exchanger; 13. Inner sleeve of heat exchanger; 14. Outer sleeve of heat exchanger; 15. Reflecting condenser lens; 16. Upper retaining rib of reflecting condenser lens; 17. Lower retaining rib of reflecting condenser lens; 18. Lens frame adjustment support rod; 19. Support frame; 20. Positioning pulley; 21. 21. Passive tracking ring; 22. Angle positioning gear; 23. Push plate; 24. Thermal element; 25. Large expansion metal sheet; 26. Small expansion metal sheet; 27. Hydraulic / pneumatic expansion metal sheet; 28. Hydraulic / pneumatic push rod; 29. ​​Hydraulic / pneumatic medium; 30. Spiral flow channel; 31. Regional adjustment support frame; 32. Linkage rod; 33. Threaded roller; 34. Manual adjustment disc; 35. Regional bracket fixing disc; 36. Arc-shaped slot plate; 37. Eccentric self-locking handle; 38. Eccentric wheel; 39. Limit mark; 40. Limit indicator slot. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0026] Example 1 like Figures 1-2 As shown, this invention provides a wide-adaptability microtrough solar thermal collector system, including a reflective concentrator assembly 1, a modular linkage rod 2, a heat exchanger 3, a manifold 4, and a support and adjustment mechanism. The support and adjustment mechanism includes an eccentric self-locking manual adjustment system 5 and a thermally driven passive tracking system. Reflective concentrator assemblies 1 are installed at both ends of the manifold 4. The heat exchanger 3 is located inside the manifold 4. The reflective concentrator assemblies 1 are rigidly connected to each other via the modular linkage rod 2. Thermally driven passive tracking systems are installed at both ends of the reflective concentrator assemblies 1. The eccentric self-locking manual adjustment system 5 includes a regional linkage adjustment mechanism 6. The system is configured to maintain an effective concentration ratio (equalized type) of not less than 3.0 within a 30° variation range of the solar altitude angle. The rotation center of the support and adjustment mechanism coincides with the central axis of the collector tube 9.

[0027] like Figure 3As shown, the reflecting condenser assembly 1 includes a reflecting condenser 15 and a reflecting condenser shaping rib. The reflecting condenser 15 has shaping ribs at both ends, and these ribs are divided into an upper rib 16 and a lower rib 17. The reflecting condenser 15 is fixed between the upper rib 16 and the lower rib 17. The upper rib 16 and the lower rib 17 are made of lightweight, non-deformable, and weather-resistant materials. The curved surface in the middle of the upper and lower ribs matches the curved surface of the reflecting condenser 15. Preferably, the upper surface of the upper rib 16 has a mirror surface, and the curved surface of this mirror surface is the same as the curved surface of the reflecting condenser 15, with a preferred width of 40mm. The preferred quantity of the reflective condenser lens shaping rib plate is 4 sets, and the preferred width of the upper rib plate is 40mm; the rib plate can be made of lightweight metal, carbon fiber, or bakelite.

[0028] like Figure 4-5 As shown, the heat-driven passive tracking system includes an angle positioning gear 22, a passive tracking ring 21 inside the angle positioning gear 22, a positioning pulley 20 inside the passive tracking ring 21, and 3-6 slots on the outer surface of the passive tracking ring 21. Inside each slot is a lens frame adjusting rod 18, a push plate 23, and a thermal element 24. The lens frame adjusting rod 18 is rigidly fixed to the reflecting condenser lens 15. Below the lens frame adjusting rod 18 is the push plate 23, whose light-facing surface is connected to one end of the thermal element 24, and the other end of the thermal element 24 is connected to the end of the light-facing surface of the slot. The push plate 23 is slidably connected to the slot. A heat collection tube 9 is positioned above the reflecting condenser lens assembly 1, with both ends of the heat collection tube 9 fixed to the positioning pulley 20. The heat-driven passive tracking system is located in the micro-groove support frame 19 system at both ends of the heat collection tube 9.

[0029] like Figure 6 As shown, the thermistor 24 is a bimetallic strip, a hydraulic / pneumatic expansion metal strip 27, or a hydraulic / pneumatic push rod 28. The bimetallic strip is composed of a large expansion metal strip 25 and a small expansion metal strip 26 with different expansion coefficients, and the expansion stroke length can be increased by stacking multiple sets. The hydraulic / pneumatic push rod 28 is filled with a low-boiling-point hydraulic / pneumatic medium 29. After being heated by solar radiation, the medium vaporizes or expands in a near-linear manner, pushing the piston rod to produce displacement. The outer surface of the thermistor 24 can be coated with a heat-absorbing film, preferably paint. The thermistor 24 can produce an effective stroke of 15-25 mm within the operating temperature range of 50-150℃.

[0030] like Figures 7-8As shown, the heat collector tube 9 includes an inner wall 10 and an outer wall 11. A heat exchanger 3 is installed inside the heat collector tube 9. The heat exchanger 3 has a spiral double-layered tube structure, including an inner tube 13 and an outer tube 14. Radial fins 12 are arranged between the outer tube 14 and the inner wall 10, and are in close contact with both the inner wall 10 and the outer tube 14. A spiral flow channel 30 is formed on the wall of the inner tube 13, creating a spiral flow channel for the medium. The radial fins 12 are made of a metal material that is elastic, high-temperature resistant, and has good heat transfer performance, with a high-temperature resistance of not less than 400℃, preferably aluminum alloy.

[0031] The header 4 has a double-layered tube structure, including an inner header tube 7 and an outer header tube 8, as well as an outer casing and insulation layer. The inner header tube 7 is coaxially arranged inside the outer header tube 8. Both the inner header tube 7 and the outer header tube 8 are made of high-temperature resistant material, and the square of the diameter of the inner header tube 7 is half the square of the diameter of the outer header tube 8. The first end of the heat exchanger outer sleeve 14 is connected to the outer header tube 8, and the end of the heat exchanger outer sleeve 14 is closed. The first end of the heat exchanger inner sleeve 13 is connected to the inner header tube 7, and the end of the heat exchanger inner sleeve 13 is open. The square of the diameter of the heat exchanger inner sleeve 13 is half the square of the diameter of the heat exchanger outer sleeve 14. This spiral double-layered tube structure of the heat exchanger 3 improves the heat transfer coefficient by more than 35% compared to a U-tube and reduces the flow resistance by more than 90% compared to a U-tube.

[0032] like Figures 9-12 As shown, the regional linkage adjustment mechanism 6 includes a regional linkage support frame 31 and a linkage rod 32 set at both ends of the linkage area. A manual adjustment disk 34 is set on the inner side of the regional linkage support frame 31. The linkage rod 32 is connected to the manual adjustment disk 34. A threaded roller 33 is set on the linkage rod 32. The threaded roller 33 meshes with the angle positioning gear 22. A regional support fixing disk 35 is set inside the manual adjustment disk 34. The regional linkage support frame 31 is slidably connected to the manual adjustment disk 34 through the regional support fixing disk 35. The linkage rod 32 is preferably made of stainless steel round tube.

[0033] An eccentric wheel 38 is provided on the area support fixing plate 35, and an eccentric self-locking handle 37 is mounted on the eccentric wheel 38. An arc-shaped slot plate 36 is provided on the manual adjustment plate 34 at a position corresponding to the eccentric wheel 38. The center of the arc of the arc-shaped slot plate 36 coincides with the central axis of the heat collection tube 9. A limit mark 39 is provided on the arc-shaped slot plate 36, and an arc-shaped limit indicator slot 40 is provided on the outer side of the arc-shaped slot plate 36. Preferably, six limit indicator slots 40 are provided in the manual adjustment plate 34. Each limit indicator slot 40 is marked with a corresponding adjustment time range above and below it. The number of limit indicator slots 40 can be increased or decreased according to the adjustment frequency requirements, and the corresponding date range is linearly distributed with the number of slots.

[0034] The reflecting condenser 15 adopts a three-segment composite curve design, specifically including: a pure parabolic segment occupying 60% of the arc length in the central region, a mixed parabolic and involute segment occupying 20% ​​of the arc length in the transition region, and an involute-dominant segment occupying 20% ​​of the arc length in the edge region. The boundary angle of the reflecting condenser 15 is 90°±25°, and the opening width A of the reflecting condenser 15 and the outer diameter D of the heat collection tube 9 satisfy 2.5<A / (πD / 2)<4.0. The curved surfaces of the upper retaining rib plate 16 and the lower retaining rib plate 17 of the reflecting condenser both adopt the same three-segment composite curve design as the reflecting condenser.

[0035] The mathematical expression for the composite curve of a reflecting condenser lens: ; Where f is the focal length, k is the correction factor (0.05-0.15), x1 is the x-coordinate of the edge point, and the key optical indicator that this design extends the acceptance angle from ±5° of a pure parabola to ±15°.

[0036] The reflecting condenser lens 15 can be made of one of the following mirror materials: glass, metal, or plastic. A thin metal mirror with a thickness of 0.5-1mm is preferred, and aluminum mirror is the most common. The thin metal mirror is shaped using four sets of reflecting condenser lens shaping ribs. The optimal parameter configuration of the system has three preferred embodiments, which are as follows: First preferred embodiment (economic type): opening width A = 325±25mm, outer diameter of collector tube 9 D = 47±5mm, concentration ratio C = 2.2±0.2; Second preferred embodiment (balanced type): opening width A = 472 ± 25 mm, outer diameter of collector tube 9 D = 47 ± 5 mm, concentration ratio C = 3.2 ± 0.2; Third preferred embodiment (high performance type): opening width A = 516±25mm, outer diameter of collector tube 9 D = 47±5mm, concentration ratio C = 3.5±0.3.

[0037] This wide-adaptive microtrough solar thermal system achieves efficient solar thermal collection at different latitudes and solar altitude angles through the coordinated operation of four core components: optical concentrating, thermally driven passive tracking, eccentric self-locking manual adjustment, and high-efficiency heat exchange circulation. Furthermore, it eliminates the need for costly and high-precision active tracking equipment. The specific working principle is as follows: like Figure 13As shown, the reflector condenser 15 adopts a three-segment composite curve design with a boundary angle of 90°±25°. The central pure parabolic segment ensures efficient light concentration when the sun is directly incident. The transition segment and the edge segment maximize the collection capacity of obliquely incident light through a hybrid / dominant design of parabolic and involute surfaces, so that the sunlight is concentrated on the surface of the heat collection tube 9 after reflection to form a light band. It can still maintain a stable effective light concentration ratio within a range of 30° change in solar altitude angle. At the same time, through parameter optimization of the opening width A and the outer diameter D of the heat collection tube 9, it matches the light concentration requirements of different application scenarios and achieves efficient light concentration without light spillage loss.

[0038] To address the dynamic changes in solar altitude angle within the same day, the system employs a thermally driven passive tracking system to achieve automatic tracking without external energy: The thermal element 24 (bimetallic strip / hydraulic / pneumatic push rod 28) receives solar radiation and its temperature rises. The bimetallic strip bends and deforms due to the difference in its expansion coefficients. The low-boiling-point medium inside the hydraulic / pneumatic push rod 28 vaporizes / expands upon heating, pushing the piston rod. Both generate an effective stroke of 15-25mm at 50-150℃. This movement, via the push plate 23, drives the mirror frame adjustment rod 18, which in turn drives the reflecting condenser mirror 15 to rotate around the central axis of the heat collection tube 9. This achieves real-time adaptive tracking of the sun's position by the condenser mirror, with a tracking accuracy within ±3°. When the ambient temperature decreases, the thermal element 24 returns to its initial state, causing the condenser mirror to reset.

[0039] like Figure 14 As shown, the solar altitude angle variation characteristics of the target latitude region determine the optimal combination of light concentration ratio C and receiving angle 2θ, where the light concentration ratio C ranges from 2.5 to 4.0 and the receiving angle 2θ ranges from 25° to 38°. For application scenarios with a solar altitude angle variation of 30°, the light concentration ratio C is configured to be 3.0-3.5 and the receiving angle 2θ is configured to be 30°~35° (reflection zone light band effect: the reflection of the concentrator 15 on the surface of the heat collection tube 9 forms a light band with a certain width).

[0040] To address the long-term changes in solar altitude angle caused by seasonal variations, the eccentric self-locking manual adjustment system 5 enables synchronized angle adjustment of the entire row of modules: The eccentric self-locking handle 37 is moved to release the locking mechanism, and the manual adjustment discs 34 at the beginning and end of the linkage area are rotated. This drives the threaded roller 33 to rotate via the linkage rod 32. The threaded roller 33 meshes with the angle positioning gear 22, which in turn drives the reflective condenser lens 15 to rotate via the lens frame adjustment rod 18. After rotating the passive tracking ring 21 to the limit mark 39 on the arc-shaped slot plate 36, the eccentric self-locking handle 37 is pressed down to achieve angle self-locking fixation.

[0041] Manual adjustment discs 34 are installed at the north and south ends of the support frame. A linkage rod 32 rotates the threaded roller 33, which in turn rotates the angle positioning gear 22 of each module. The lens frame adjustment rod 18, embedded in the angle positioning gear 22, rotates the interference condenser lens to adjust its angle. An arc-shaped slot plate 36 is installed on the area support fixing plate 35, with the arc center of the slot plate coinciding with the central axis of the heat collection tube 9. During adjustment, the eccentric self-locking handle 37 is moved to release the locking mechanism, and the manual adjustment disc 34 is rotated to make the passive tracking ring 21 rotate to the limit mark 39 on the slot plate. Then, the handle is pressed down to achieve self-locking. Adjustment of one module in the entire row is synchronized across the entire row. A single operator can complete the entire row's adjustment with an accuracy of ±0.5°.

[0042] The manual adjustment disc 34 preferably has six limit indicator slots 40. Each limit indicator slot 40 is marked with a time, meaning that within this time interval, the fixed limit indicator 39 points to this limit indicator slot 40. The six limit indicator slots 40 are marked with the following dates in order: (November 20; January 20); (January 20 to February 20; October 20 to November 20); (February 20 to March 20; September 20 to October 20); (March 20 to April 20; August 20 to September 20); (April 20 to May 20; July 20 to August 20); (May 20; June 20). The limit indicator slot 40 is related to the adjustment frequency. Increasing the adjustment frequency will improve the system effect. More limit indicator slots 40 can be set. The date range of the limit indicator slot 40 is allocated according to the quantity and type.

[0043] The solar collector tube 9 absorbs and concentrates solar energy, converting it into heat energy. The heat is then rapidly transferred to the outer tube 14 of the heat exchanger through the radial fins 12. The heat exchanger 3 adopts a spiral double-layer tube structure. The medium enters the spiral flow channel 30 of the inner tube 13 of the heat exchanger from the inner tube 7 of the manifold, forming a highly efficient heat exchange with the medium in the outer tube, which greatly improves the heat transfer coefficient and reduces the flow resistance. The medium after heat exchange is output through the outer tube 8 of the manifold, completing the conversion and transportation of solar energy into heat energy. The double-layer tube structure and insulation layer design of the manifold 4 can effectively reduce heat loss and ensure heat exchange efficiency.

[0044] Therefore, this invention employs a wide-adaptability microtrough solar thermal system, which achieves a balance between low cost and high efficiency through a three-segment composite curve reflecting concentrator, a dual-mode support and adjustment mechanism combining thermally driven passive tracking and eccentrically self-locking manual adjustment, coupled with a spiral double-layer shell-and-tube internal heat exchanger and a standardized modular design. This system eliminates the need for high-cost, high-precision active tracking equipment; the thermally driven element can achieve automatic solar tracking without external energy at temperatures ranging from 50-150°C; the manual adjustment system enables synchronous angle adjustment of the entire row of modules; and the balanced effective concentration ratio is no less than 3.0 within a 30° range of solar altitude angle variation. Furthermore, it can match the concentration ratio and receiving angle parameters according to different latitudes. Simultaneously, the heat exchanger achieves a heat transfer coefficient increase of over 35% and a flow resistance reduction of over 90% compared to traditional U-tube systems. The system boasts low manufacturing costs, simple operation and maintenance, and is suitable for distributed industrial and commercial applications with medium-temperature heat demands ranging from 50°C to 300°C, effectively resolving the industry's technical contradictions of high cost in traditional trough systems and low efficiency in small, fixed systems.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A widely adaptable microtrough solar thermal collector system, characterized in that, It includes a reflective concentrator assembly, a modular linkage rod, a heat exchanger, a header, and a support and adjustment mechanism. The support and adjustment mechanism includes an eccentric self-locking manual adjustment system and a heat-driven passive tracking system. Reflective concentrator assemblies are installed at both ends of the header. Each reflective concentrator assembly includes a reflective concentrator and a heat collection tube. The heat exchanger is located inside the header. The reflective concentrator assemblies are connected to each other via modular linkage rods. The heat-driven passive tracking system is installed at both ends of the reflective concentrator assembly. The eccentric self-locking manual adjustment system includes a regional linkage adjustment mechanism.

2. The wide adaptability microtrough solar thermal collector system according to claim 1, characterized in that, The reflective condenser is provided with reflective condenser shaping ribs at both ends. The reflective condenser shaping ribs include an upper rib and a lower rib, and the reflective condenser is fixed between the upper rib and the lower rib.

3. The wide adaptability microtrough solar thermal collector system according to claim 1, characterized in that, The heat-driven passive tracking system includes an angle positioning gear, a passive tracking ring inside the angle positioning gear, a positioning pulley inside the passive tracking ring, a slot on the passive tracking ring, a lens frame adjustment rod, a push plate and a thermal element inside the slot, a push plate below the lens frame adjustment rod, a thermal element connected to the light-facing surface of the push plate, and the push plate slidably connected to the slot. A heat collection tube is installed above the reflective condenser lens assembly, and both ends of the heat collection tube are fixed to the positioning pulley.

4. The wide adaptability microtrough solar thermal collector system according to claim 3, characterized in that, The thermal element is a bimetallic strip or a hydraulic / pneumatic push rod. The bimetallic strip includes a large / small expansion metal strip and a hydraulic / pneumatic expansion metal strip. The hydraulic / pneumatic push rod is filled with a hydraulic / pneumatic medium. The outer surface of the thermal drive element can be coated with a heat-absorbing film.

5. A wide-adaptability microtrough solar thermal collector system according to claim 3, characterized in that, The heat collection tube includes an inner wall and an outer wall. A heat exchanger is installed inside the heat collection tube. The heat exchanger includes an inner tube and an outer tube. Radial fins are provided between the outer tube and the inner wall of the heat collection tube. A spiral flow channel is provided on the inner wall of the heat exchange tube.

6. A wide-adaptability microtrough solar thermal collector system according to claim 5, characterized in that, The header includes an inner header pipe and an outer header pipe. The square of the diameter of the inner header pipe is half the square of the diameter of the outer header pipe. The first end of the heat exchanger outer sleeve is connected to the outer header pipe, and the end of the heat exchanger outer sleeve is closed. The first end of the heat exchanger inner sleeve is connected to the inner header pipe, and the end of the heat exchanger inner sleeve is open. The square of the diameter of the heat exchanger inner sleeve is half the square of the diameter of the heat exchanger outer sleeve.

7. A wide-adaptability microtrough solar thermal collector system according to claim 1, characterized in that, The regional linkage adjustment mechanism includes regional linkage support frames and linkage rods at both ends. A manual adjustment disc is installed inside the regional linkage support frame. The linkage rod is fixedly connected to the manual adjustment disc. A threaded roller is installed on the linkage rod. The threaded roller is meshed with an angle positioning gear. A regional support fixing disc is installed inside the manual adjustment disc. The regional linkage support frame is slidably connected to the manual adjustment disc through the regional support fixing disc.

8. A wide-adaptability microtrough solar thermal collector system according to claim 7, characterized in that, An eccentric wheel is located below the area bracket fixing plate, and an eccentric self-locking handle is installed on the eccentric wheel. An arc-shaped slot plate is located below the manual adjustment plate at a position corresponding to the eccentric wheel. A limit mark is set on the arc-shaped slot plate, and an arc-shaped limit indicator slot is set on the outer side of the arc-shaped slot plate.

9. A wide-adaptability microtrough solar thermal collector system according to claim 1, characterized in that, The reflecting concentrator adopts a three-segment composite curve design, including: a pure parabolic segment with a central region of 60% arc length, a mixed parabolic and involute segment with a transition region of 20% arc length, and an involute-dominant segment with a peripheral region of 20% arc length; the boundary angle of the reflecting concentrator is 90°±25°, and the opening width A and the outer diameter D of the heat collection tube satisfy 2.5<A / (πD / 2)<4.

0.

10. A wide-adaptability microtrough solar thermal collector system according to claim 9, characterized in that, The reflecting condenser is made of glass, metal, and plastic. The upper and lower rib plates of the reflecting condenser adopt a three-segment composite curve design.

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