Parabolic trough collector module and parabolic trough collector unit

Abstract

A parabolic trough collector module (1) comprising an absorber tube (3) with a central axis (A), comprising a parabolic reflector (5) which focuses solar radiation onto the absorber tube (3) and has a reflector surface (7), the parabolic reflector (5) having two longitudinal sides (5b), which extend parallel to the central axis (A) of the absorber tube (3), and two end sides (5a), and comprising a stand system (9) having a first stand (9a) and a second stand, which are each arranged on one of the end sides (5a) of the parabolic reflector (5), the parabolic reflector (5) having a support structure (11) which extends along the two longitudinal sides (5b) and the two end sides (5a), and the parabolic reflector (5) being mounted on an upper portion (9b) of the first stand (9a) pivotably about an axis of rotation (D) via the support structure (11) by means of a radial bearing (10) in each case, and comprising a drive device (19), which pivots the parabolic reflector (5) about the axis of rotation (D) for tracking according to the position of the sun and for returning to a starting position, the drive device (19) having a drive motor (20) and an output device (22) which is connected to the support structure (11), the drive motor driving the output device (22) in order to transmit the rotational movement to the parabolic reflector (5), the output device (22) being axially mounted on a lower portion (9c) of the first stand (9a) in order to form an axial mount (24) for the parabolic reflector (5).

Description

[0001] 251115WO RÜ / ol

[0002] Parabolic trough collector module and parabolic trough collector unit

[0003] The present invention relates to a parabolic trough collector module according to the preamble of claim 1 and to a parabolic trough collector unit composed of several parabolic trough collector modules arranged in a series.

[0004] Solar thermal power plants use the energy of sunlight to heat a heat transfer fluid, with the heat often being used to generate electricity. The solar radiation is focused onto an absorber, in which the heat transfer fluid circulates, using optical concentrators. The optical concentrators represent the largest investment in solar thermal power plants and significantly influence their efficiency.

[0005] Well-known solar thermal power plants utilize parabolic trough collectors. A parabolic trough collector consists of an elongated collector structure with a parabolic cross-section. Typical aperture openings are 5–7 m. Individual parabolic trough collector modules, also called solar collector elements (SCEs), are approximately 12 m long. Several such modules are assembled to form parabolic trough collector units, which are generally oriented north-south. The modules within a unit are typically driven and tilted together to track the sun's position.

[0006] The previously known parabolic trough collector units have a support structure consisting of several stanchions, between which the individual parabolic trough collector modules are suspended. The parabolic trough collector modules are equipped with a torsion box or a torsion tube, which allows them to withstand bearing friction moments and wind forces with torsional rigidity. The parabolic trough collector modules have a supporting structure that typically supports both the parabolic reflectors and the absorber tubes via absorber tube supports.

[0007] A previously known parabolic trough collector module and a previously known parabolic trough collector unit are known, for example, from DE 10 2016 200 034 Al or from DE 10 2015 208 001 Al of the applicant, from which a parabolic trough collector module with the features of the preamble of claim 1 is revealed.

[0008] In such parabolic trough collector units, a central pylon is provided, on which the drive device is located. This pylon is positioned centrally within the parabolic trough collector unit between two parabolic trough reflector modules and is connected to one or both of these modules. An equal number of parabolic trough collector modules extend from both sides of the central pylon. Simple stands without a drive device can be arranged between the additional parabolic trough collector modules. Furthermore, the parabolic trough collector modules are axially supported at the top of the central pylon.

[0009] Particularly due to wind forces, axial forces are exerted on the parabolic trough collector modules, which are then transferred to and absorbed by the axial bearing on the central pylon. These axial forces cause the central pylon to bend, potentially leading to a collision with the parabolic reflectors of adjacent parabolic trough collector modules. Therefore, the central pylon is designed to be particularly robust and rigid to reduce or prevent bending.

[0010] This necessitates a high level of design and financial investment in the production of the central pylon, which is comparatively large. Due to the central pylon's large dimensions, the required gap between the adjacent parabolic trough collector modules, between which the central pylon is positioned, must be correspondingly large. For example, the required gap can be up to 80 cm.

[0011] Due to the large gap, correspondingly large optical losses occur in the middle of a parabolic trough collector unit, since no reflected solar radiation can hit the absorber tube in the area of ​​the gap.

[0012] Particularly when using molten salt as a heat transfer medium, and the absorber tubes are emptied at night, the aforementioned gaps can lead to specific problems. This is because the absorber tubes must be heated to a temperature exceeding, for example, 280°C before being filled with the liquid molten salt. Due to the gap created by the central pylon, this requirement cannot necessarily be guaranteed. Therefore, there is a risk that the molten salt will solidify in the section of the absorber tube located within the gap, potentially leading to plug formation.

[0013] It is therefore the object of the present invention to create a parabolic trough collector module with which large gaps can be avoided, while at the same time more cost-effective mounting can be used.

[0014] It is therefore the object of the present invention to create a parabolic trough collector unit with such a parabolic trough collector module.

[0015] The parabolic trough collector module according to the invention is defined by the features of claim 1.

[0016] A parabolic trough collector unit according to the invention is defined by the features of claim 11. The parabolic trough collector module according to the invention comprises an absorber tube with a central axis, a parabolic reflector with a reflector surface for focusing solar radiation onto the absorber tube, and a support structure. The parabolic reflector has two longitudinal sides extending parallel to the central axis of the absorber tube and two end faces. The support structure comprises a first and a second support, each arranged at one of the end faces of the parabolic reflector. The parabolic reflector has a support structure extending along the two longitudinal sides and the two end faces, wherein the parabolic reflector is pivotably mounted about an axis of rotation on the support structure by means of a radial bearing at an upper section of one of the supports. The support structure thus surrounds the parabolic reflector in a frame-like manner.Furthermore, a drive device is provided which pivots the parabolic reflector around the axis of rotation to track the sun's position. The drive device comprises a drive motor and an output device connected to the support structure, with the drive motor driving the output device to transmit the rotary motion to the parabolic reflector. The invention is characterized in that the output device is axially mounted on a lower section of the first stator to form an axial bearing for the parabolic reflector.

[0017] In the context of the invention, an upper section of a stand is understood to be the section of the stand which, in a basic position of the parabolic reflector in which the aperture opens upwards, extends upwards over the reflector surface.

[0018] In the context of the invention, a lower section of a stand is understood to be the section of the stand which, in a basic position of the parabolic reflector in which the aperture opens upwards, is located below the parabolic reflector.

[0019] Because the drive unit is axially mounted on the lower section of the first stator, axial forces acting on the parabolic reflector are transmitted via the drive unit to the lower section of the first stator and absorbed there in the axial direction. Since the lower section of the first stator is always located below the parabolic reflector, a parabolic trough collector unit can be created using the parabolic trough collector module according to the invention, which has comparatively small gaps of, for example, only 20 cm, since a stator with a lower bending stiffness, at least in its upper region, compared to previous central pylons, can be arranged as a central pylon between two parabolic trough collector modules.This is made possible by the fact that no axial forces are introduced into the section of the stand located between the parabolic reflectors, thus preventing any significant bending due to axial forces in this area. As a result, the stand, on which the output device is mounted, can have a comparatively simple and cost-effective design.

[0020] Furthermore, by narrowing the gaps, the previously identified problems regarding losses or preheating are reduced or avoided.

[0021] Preferably, the support structure comprises two support elements, one of which is arranged at each of the two end faces and includes two torsionally rigid support elements extending parallel to the longitudinal sides and connected to the support elements. Such a support structure allows the torsionally rigid support elements to exhibit particularly high torsional stiffness, so that when a parabolic reflector is driven, the rotational movement is advantageously transmitted over the entire length of the parabolic reflector. At the same time, the support elements arranged at the end faces can be designed differently from the torsionally rigid support elements and, for example, exhibit lower torsional stiffness. This allows the support structure to be manufactured relatively cost-effectively overall.The torsionally rigid support elements can be arranged, in particular, along the longitudinal edges of the parabolic reflector, extending along its sides. Preferably, the radial bearings are arranged on one of the support elements and / or the output device is connected to one of the support elements. The support elements advantageously allow the parabolic reflector to be radially mounted. The drive motion from the output device to the support structure of the parabolic reflector can also be advantageously transmitted via the support elements.

[0022] The axis of rotation can correspond to the central axis of the absorber tube. This means that the absorber tube does not need to be moved when the parabolic reflector is rotated, and expensive and failure-prone rotary seals between the absorber tube and the collector connection pipe can be omitted.

[0023] In particular, it can be provided that the center of gravity axis of the parabolic reflector corresponds to the axis of rotation of the parabolic reflector. This can be achieved, for example, by selecting an appropriate material for the supporting structure and by a suitable arrangement. By designing the parabolic reflector with its center of gravity axis corresponding to the axis of rotation, the parabolic reflector can be pivoted in a particularly advantageous manner.

[0024] The parabolic reflector can, for example, be designed in a lightweight construction, for example by means of a sandwich structure and a thin glass mirror.

[0025] The absorber tube can be at least partially supported by the stands. For example, the absorber tube can extend through the radial bearings. Such a design has proven to be particularly advantageous.

[0026] Preferably, the support elements and / or the torsionally rigid support elements are arranged at least partially above a horizontal plane running through the central axis of the absorber tube in a home position of the parabolic reflector. This allows the parts of the support elements or the torsionally rigid support elements arranged above the horizontal plane to create a counterweight to the sections of the parabolic reflector located below the horizontal plane, so that pivoting the parabolic reflector is possible with comparatively little effort, since the counterweight facilitates pivoting from the home position.

[0027] The output device can be designed in a ring- or circular sector shape, preferably in the form of a semi-ring. Preferably, in a basic position of the parabolic reflector, the output device is located completely below the parabolic reflector. The center point of the ring-sector-shaped output device can be located on the axis of rotation. The pivoting movement can advantageously be initiated into the parabolic reflector by rotating the ring-sector-shaped output device accordingly about the axis of rotation.

[0028] The drive of the output device by the drive motor can be achieved by arranging a toothed or chain structure on the output device, into which a pinion of the drive motor engages. The drive motor can be attached, in particular, to the lower section of the stator on the first stator that supports the output device.

[0029] Preferably, the output device has a U- or H-shaped cross-section, with the tooth or chain structure arranged in a groove formed by the cross-sectional shape. By designing the output device with a U- or H-shaped cross-section, it can be made particularly rigid, thus advantageously transferring the axial forces of the parabolic reflector to the first stator via the output device.

[0030] The groove in which the toothed or chain structure is arranged can, for example, be directed downwards. This allows the motor to be advantageously positioned below the output device. The first stator, on which the output device is mounted, can be made particularly rigid in its lower region by, for example, providing at least one additional support that is axially attached to the first stator.

[0031] In a particularly preferred embodiment of the invention, the output device is connected to one of the support elements via at least one strut. This allows the axial force exerted on the parabolic reflector, for example due to wind, to be advantageously transmitted to the output device via the support elements. In particular, several struts can be provided, enabling a relatively uniform force transmission to the output device, thus preventing bending of the output device.

[0032] The axial support can be formed by two roller bearings that bear against the output device on both sides in the axial direction of the parabolic reflector. For example, the roller bearings can each have several rollers arranged next to each other.

[0033] The invention further relates to a parabolic trough collector unit comprising at least one parabolic trough collector module according to the invention and several further parabolic trough collector modules, wherein the parabolic trough collector module according to the invention and the further parabolic trough collector modules are arranged in a series and the parabolic trough collector module according to the invention and the further parabolic trough collector modules have a common, continuous absorber tube string made of absorber tubes.

[0034] The other parabolic trough collector modules are essentially designed like the parabolic trough collector module according to the invention, but without the drive device and the axial bearing. The parabolic trough collector unit according to the invention thus comprises one parabolic trough collector module according to the invention, which is arranged centrally within the parabolic trough collector unit. The other parabolic trough collector modules are arranged accordingly next to the parabolic trough collector module according to the invention, so that the first stand with the drive device of the parabolic trough collector module according to the invention forms the central stand of the parabolic trough collector unit.

[0035] In the parabolic trough collector unit according to the invention, it can be provided in particular that the support structures of two adjacent parabolic trough collector modules are connected to each other. This allows the pivoting movement to be transferred from one parabolic trough collector module to the other in a particularly advantageous manner, so that only one central drive device is necessary.

[0036] Each pair of adjacent parabolic trough collector modules shares a common support. In this way, the parabolic trough collector unit according to the invention can be designed in a particularly advantageous manner.

[0037] The invention will be explained in more detail below with reference to the following figures.

[0038] They show:

[0039] Fig. 1 shows a schematic representation of a parabolic trough collector module according to the invention in an axial view.

[0040] Fig. 2 shows a schematic side view of a parabolic trough collector module according to the invention.

[0041] Fig. 3 shows a schematic partial representation of the axial bearing and Fig. 4 shows a schematic representation of a parabolic trough collector unit according to the invention with a parabolic trough collector module according to the invention.

[0042] Fig. 1 shows a schematic view of a parabolic trough collector module 1 according to the invention in the axial direction.

[0043] The parabolic trough collector module 1 has an absorber tube 3 with a central axis A, and a parabolic reflector 5 with a reflector surface 7, via which solar radiation can be concentrated onto the absorber tube 3.

[0044] The parabolic reflector 5 further comprises a support structure 11, consisting of two support elements 17 arranged on the end faces 5a of the parabolic reflector 5, and support elements 21 arranged along the longitudinal sides 5b of the parabolic reflector 5. The longitudinal sides 5b of the parabolic reflector 5 extend parallel to the central axis A of the absorber tube 3.

[0045] The parabolic trough collector module 1 also has a support structure 9, which consists of a first support 9a and a second support (not shown), each located on one of the end faces 5a of the parabolic reflector 5.

[0046] In an upper section 9b of the first stand 9a, a radial bearing 10 is provided, via which the parabolic reflector 5 is pivotably mounted by means of the support structure 11. For this purpose, the radial bearings 10 are each attached to the support elements 17. A radial bearing is also provided in the second stand. The absorber tube 3 extends through the radial bearings 10.

[0047] A drive device 19 is arranged on the first stator 9a. The drive device 19 has a drive motor 20, which drives an output device 22. The output device 22 is designed as a semi-circular ring, each end of which is connected to one of the support elements 17 of the support structure 11. The drive motor 20 drives the output device 22, causing it to rotate about its center point, which lies on the axis of rotation D. The rotational movement is transmitted to the support structure 11, causing the parabolic reflector 5 to pivot about the axis of rotation D.

[0048] As can best be seen from Fig. 2, the radial bearing 10 is arranged in the upper section 9b of the stand 9a. The upper section 9b of the stand 9a is the section of the stand 9a that extends upwards over the reflector surface 7 in a basic position of the parabolic reflector 5, as shown in Fig. 1, in which the aperture opens upwards. For example, the upper section could be a region corresponding to the upper quarter of the stand 9a.

[0049] The output device 22 is axially mounted in a lower section 9c of the first stand 9a to form an axial bearing 24 for the parabolic reflector 5. The lower section 9c of the first stand 9a is the section that is located below the parabolic reflector 5 in the basic position.

[0050] The output device 22 is further connected to the torsionally rigid support elements 21 by means of several struts 26. These struts advantageously allow any axial forces occurring to be transferred from the supporting structure 11 to the output device 22 and thus to the axial bearing 24.

[0051] The first upright 9a, on which the axial bearing 24 is arranged, further has an additional support 27 which extends in the axial direction from the first upright 9a.

[0052] Fig. 3 shows the axial bearing 24 schematically in detail.

[0053] The output device 22 has a cross-section that is H-shaped (double-T shape). A chain structure 28 is arranged in a groove 29 formed by the cross-sectional shape. The drive motor 20 engages the chain structure 28 by means of a pinion 20a, via which the output device 22 is then driven.

[0054] The axial bearing 24 has two roller bearings 24a which bear against the output device 22 on both sides in the axial direction of the parabolic reflector 5. The axial force acting on the output device 22 can be advantageously absorbed via the roller bearings 24a.

[0055] Fig. 4 shows a schematic representation of a parabolic trough collector unit 100 according to the invention.

[0056] The parabolic trough collector unit 100 according to the invention comprises a parabolic trough collector module 1 according to the invention and further parabolic trough collector modules 1a. The parabolic trough collector module 1 according to the invention and the parabolic trough collector modules 1a have a common continuous absorber tube string made of absorber tubes 3. The further parabolic trough collector modules 1a are essentially constructed in the same way as the parabolic trough collector module 1 according to the invention, except that they do not have a drive device.

[0057] The drive device 19 is arranged only on the first stator 9a, which forms a central stator. The drive device 19 is shown in a highly simplified form in Fig. 4. The further parabolic trough collector modules 1a are driven via the drive device 19 of the parabolic trough collector module 1 according to the invention. For this purpose, the support structures 11 of two adjacent parabolic trough collector modules 1, 1a are connected to each other.

[0058] As can be seen from Fig. 4, two adjacent parabolic trough collector modules 1, 1a share a common support 9d. In the parabolic trough collector module 1 according to the invention, the common support 9d forms the second support. List of reference symbols

[0059] 1 parabolic trough collector module 1a further parabolic trough collector module

[0060] 3 absorber tubes

[0061] 5 Parabolic reflector

[0062] 5a Front sides

[0063] 5b Long sides

[0064] 7 Reflector area

[0065] 9 Standing

[0066] 9a first stand

[0067] 9b upper section of the first stand

[0068] 9c lower section of the first stand

[0069] 9d common stand

[0070] 10 radial bearings

[0071] 11 Supporting structure

[0072] 17 load-bearing elements

[0073] 19 Drive device

[0074] 20 Drive motor

[0075] 20a gear pinion

[0076] 21 torsionally rigid support element

[0077] 22 Output device

[0078] 24 Axial bearing

[0079] 24a Roller bearing

[0080] 26 Strut

[0081] 27 support

[0082] 28 chain structure

[0083] 29 Nut

[0084] 100 parabolic trough collector units

[0085] A central axis

[0086] D axis of rotation

Claims

Patent claims 1. Parabolic trough collector module (1) with an absorber tube (3) having a central axis (A), with a parabolic reflector (5) focusing solar radiation onto the absorber tube (3) and having a reflector surface (7), wherein the parabolic reflector (5) has two longitudinal sides (5b) extending parallel to the central axis (A) of the absorber tube (3) and two end faces (5a), and with a support (9) comprising a first support (9a) and a second support, each arranged on one of the end faces (5a) of the parabolic reflector (5), wherein the parabolic reflector (5) has a support structure (11) extending along the two longitudinal sides (5b) and the two end faces (5a), wherein the parabolic reflector (5) is mounted on the support structure (11) by means of a radial bearing (10) on an upper section (9b) of the first support (9a) by means of a The pivot axis (D) is pivotably mounted and is equipped with a drive device (19).which pivots the parabolic reflector (5) about the axis of rotation (D) to track the sun's position and to return it to a starting position, wherein the drive device (19) has a drive motor (20) and an output device (22) connected to the support structure (11), wherein the drive motor drives the output device (22) to transmit the rotational movement to the parabolic reflector (5), characterized in that the output device (22) is axially mounted on a lower section (9c) of the first stator (9a) to form an axial bearing (24) for the parabolic reflector (5).

2. Parabolic trough collector module according to claim 1, characterized in that the support structure (11) has two support elements (17), wherein one of the support elements (17) is arranged on one of the two end faces (5a), and has two torsionally stiff support elements (21) extending parallel to the longitudinal sides (5b) which are connected to the support elements (17).

3. Parabolic trough collector module according to claim 2, characterized in that the radial bearings are each arranged on one of the support elements (17) and / or that the output device (22) is connected to one of the support elements (17).

4. Parabolic trough collector module according to one of claims 1 to 3, characterized in that the axis of rotation (D) corresponds to the central axis (A) of the absorber tube (3).

5. Parabolic trough collector module according to one of claims 2 to 4, characterized in that the support elements (17) and / or the torsionally stiff support elements (21) are arranged at least partially above a horizontal plane (H) passing through the central axis (A) of the absorber tube (3).

6. Parabolic trough collector module according to one of claims 1 to 5, characterized in that the drive device (22) is designed in a ring sector shape.

7. Parabolic trough collector module according to claim 6, characterized in that a tooth or chain structure (28) is arranged on the output device (22), into which a pinion gear (20a) of the motor (20) engages.

8. Parabolic trough collector module according to claim 7, characterized in that the drive device (22) has a U- or H-shaped cross-section, wherein the tooth or chain structure (28) is arranged in a groove (29) formed by the cross-sectional shape.

9. Parabolic trough collector module according to one of claims 2 to 8, characterized in that the drive device (22) is connected to one of the support elements (21) via at least one strut (26).

10. Parabolic trough collector module according to one of claims 2 to 8, characterized in that the axial bearing (24) is formed by two roller bearings (24a) which bear against the output device (22) on both sides in the axial direction of the parabolic reflector (5).

11. Parabolic trough collector unit (100) comprising at least one parabolic trough collector module (1) according to one of claims 1 to 10, and several further parabolic trough collector modules (1a), wherein the parabolic trough collector module (1) and the further parabolic trough collector modules (1a) are arranged in a series and the parabolic trough collector module (1) and the further parabolic trough collector modules (1a) have a common, continuous absorber tube string made of absorber tubes (3).

12. Parabolic trough collector unit according to claim 11, characterized in that the supporting structures (11) of two adjacent parabolic trough collector modules (1) are connected to each other.

13. Parabolic trough collector unit according to claim 11 or 12, characterized in that a common stand (9d) is arranged between two adjacent parabolic trough collector modules (1).

Images