Cylindro-parabolic solar collector

Abstract

The invention relates to a cylindro-parabolic solar collector, comprising: - a cylindro-parabolic reflector (100) provided with a focal line extending in a longitudinal direction, the reflector (100) being capable of reflecting and concentrating the solar light rays incident thereon onto the focal line; and - a support structure (300) supporting the reflector (100) and comprising an elongate central concrete torsion body (310) oriented longitudinally and a trough (330) which has a cylindro-parabolic concave upper surface supporting the reflector (100); characterized in that the trough (330) consists of a plurality of portions (T) longitudinally joined to one another and each comprising a pair of two single-piece concrete elements (M) extending symmetrically opposite each other on either side of the elongate central torsion body (310).

Description

[0001] Parabolic trough solar collector

[0002] The present invention relates to the field of solar energy capture and more particularly to a parabolic-cylindrical type solar collector.

[0003] Due to its abundant availability, its renewable nature, its reduced environmental impact compared to fossil fuels and its ability to be used in remote or non-grid connected locations, solar energy offers many advantages.

[0004] Among the various technological solutions aimed at capturing some of this energy, solar collectors make it possible to capture solar radiation and transmit its thermal energy to a heat transfer fluid in the form of heat.

[0005] We know in particular of cylindro-parabolic type collectors which include a cylindro-parabolic reflector and focus the captured light rays towards an absorber tube arranged along the linear focus of this reflector.

[0006] The tube contains a heat transfer fluid, usually oil or water, which circulates to absorb the heat generated by sunlight. The absorbed heat can then be used to produce steam, which can be used to generate electricity using a steam turbine or to provide heat for industrial processes or heating systems.

[0007] The main advantage of parabolic trough collectors lies in their ability to concentrate sunlight onto a narrow linear area, resulting in higher temperatures and better solar energy conversion efficiency.

[0008] Furthermore, parabolic trough collectors can be used in a modular fashion and combined to form large-scale solar collection systems capable of producing a significant amount of electricity or heat.

[0009] Such a cylindrical-parabolic collector classically comprises a support structure supporting the absorber tube as well as a matrix network of reflective tiles with a cross-section in a portion of a parabola, arranged in rows and columns so as to constitute the cylindrical-parabolic reflector.

[0010] As disclosed for example by document WO 2013 / 084016 A1, this support structure generally includes an elongated central torsional body oriented parallel to the linear focus of the parabolic cylindro-reflector and allowing to limit the deformations of this reflector due to the torsional forces it undergoes due to its own mass and external forces such as wind.

[0011] Made of galvanized steel or aluminum, this elongated central torsion body is generally in the form of a cylindrical tube or tubular frame.

[0012] Such a support structure also classically includes a plurality of curved lateral support arms extending symmetrically in pairs on either side of this elongated central body in directions perpendicular to the linear focus of this reflector and on which the reflective slabs are fixed.

[0013] Made for example from welded metal tubes or a stamped sheet metal side, these lateral support arms allow the load and rigidity to be distributed evenly along the surface of the reflector.

[0014] These metal support structures are generally mounted hinged to pivot around a longitudinal axis parallel to the linear focus of the reflector by means of two load-bearing pillars anchored to the ground by means of concrete foundations.

[0015] Their insufficient rigidity, however, makes them particularly sensitive to wind, so that solar collectors with such a metal support structure must be positioned in a non-electricity-generating safety configuration when the wind speed exceeds a certain predefined threshold of around 40 km / h.

[0016] We also know from document DE 31 33 906 A1, a cylindrical-parabolic type solar collector whose support structure consists of a monolithic concrete block comprising an elongated central torsion body oriented parallel to the linear focus of said reflector, as well as a trough having a concave cylindrical-parabolic upper surface supporting the reflector.

[0017] Such a concrete construction of the support structure ensures significantly greater rigidity compared to metal support structures, enabling it to withstand significantly higher wind speeds.

[0018] Unfortunately, constructing such a monolithic concrete support structure proves particularly complex and costly. Furthermore, due to its size and weight, this support structure cannot be transported and must therefore be built on-site.

[0019] Furthermore, in the months following its completion, the creep of the concrete (that is to say its ability to deform due to the permanent mechanical stresses to which it is subjected, in particular due to its own weight) leads to a significant change in the cylindro-parabolic profile of the upper surface of its trough supporting the reflector, which generates a change in the angle of reflection of the light rays, resulting in a significant decrease in the capture by the absorber tube of the light rays reflected by this reflector.

[0020] The present invention therefore aims to remedy at least partially the aforementioned drawbacks.

[0021] For this purpose, it offers a parabolic-cylindrical solar collector comprising:

[0022] - a parabolic cylindrical reflector having a linear focus extending along a longitudinal direction, said reflector being capable of reflecting and concentrating the solar light rays striking it onto said linear focus; and

[0023] - a support structure supporting said reflector and comprising a central elongated torsional body made of mineral material oriented longitudinally and a trough having a concave cylindro-parabolic upper surface supporting said reflector.

[0024] According to the invention, the trough is made up of several sections joined longitudinally to one another, each comprising a pair of two monobloc elements made of mineral material extending symmetrically opposite each other on either side of the central torsionally elongated body. Furthermore, also according to the invention, in order to achieve an optimal compromise between its rigidity and its mass, each monobloc element includes a supporting arch having a concave upper surface with a semi-parabolic profile, as well as several curved lateral support arms extending from the underside of the supporting arch and across its entire transverse width.

[0025] Such a construction of the trough supporting the reflector from monobloc elements in mineral material allows, due to their contained dimensions, for these elements to be prefabricated in advance with a homogeneous quality and at a reduced cost on production sites located away from the place of installation of the solar collector.

[0026] Furthermore, such a construction makes it easy to vary the longitudinal depth of the solar collector by simply modulating the number of sections made from the same monobloc elements of mineral-based material.

[0027] Each said section also preferably comprises several connecting elements fixedly linking each of the internal end edges opposite two said lateral support arms of its two said monobloc elements, and each being fixedly mounted overlapping on said elongated central torsional body.

[0028] In order to optimize the stability of the connection between the two monobloc elements of the same section, all the said lateral support arms of the two said monobloc elements constituting the same said section are preferably connected two by two by a said respective connecting element.

[0029] According to a preferred construction ensuring easy assembly, each said inverted U-profile connecting member advantageously comprises a top plate and two substantially parallel lateral branches each fixed by screwing against the inner end edge of a respective lateral support arm of a corresponding monobloc element.

[0030] In order to ensure optimal assembly quality, the attachment of each said lateral branch of a said connecting member to a said respective lateral support arm is preferably carried out by means of at least two vertically spaced screws, each passing through a respective orifice provided in this lateral branch and screwing into the internal thread of a corresponding anchor sleeve sealed in the original mineral material forming this lateral support arm.

[0031] For reasons of quality and ease of assembly, the top plate of each said connecting element is advantageously screwed onto the top of said torsionally elongated central body by means of at least one screw passing through a respective hole provided in this plate and screwing into the internal thread of a corresponding anchoring sleeve sealed in the original mineral material forming said torsionally elongated central body.

[0032] According to a preferred conformation, each of said lateral branches of said connecting member has a lower end portion projecting below said lateral support arm on which it is fixed.

[0033] In order to secure the sections to the torsionally elongated central body, the lower end portions of the lateral branches of each connecting member are advantageously screwed each onto a respective lateral side of the torsionally elongated central body by means of at least one screw passing through a respective orifice provided in this lower end portion and screwing into the internal thread of a corresponding anchoring sleeve sealed in the original mineral material forming this torsionally elongated central body.

[0034] In order to compensate for the consequences of the creep phenomenon of the material forming the monobloc elements, said collector preferably includes adjustment means allowing fine readjustment of the inclination of each of said monobloc elements with respect to said torsionally elongated central body, said adjustment means comprising, at the level of each interface zone between said lower end portion of said lateral branch of said connecting member and a lateral side of said torsionally elongated central body, at least one screw screwed into a respective thread provided on this lower end portion and whose free internal end of its protruding portion through this thread rests against a corresponding lateral face of this torsionally elongated central body.

[0035] To prevent the free ends of the shanks of these screws from bearing directly against the mineral material and risking damage to it, the two lateral faces of said central torsionally elongated body preferentially present, at each interface zone, a corresponding metal contact plate sealed in the mineral material and against which rest the free end(s) of said screw(s) opening through the thread(s) provided on said lower end portion of a corresponding lateral branch.

[0036] According to one embodiment, said support structure may be devoid of said connecting elements linking the two monobloc elements of each section, each said monobloc element of a said section being mounted independently on said torsionally elongated central body by means of several interface devices each ensuring the attachment of a respective lateral support arm of this monobloc element to this torsionally elongated central body.

[0037] Each said interfacing device may in particular include a stepped profile upper interfacing element consisting of an upper riser fixed by screwing against the upper part of the inner end edge of a said respective support arm, a tread and a lower riser in which is formed an inverted U-shaped notch opening onto its lower edge, said lower riser being mounted overlapping via said notch on one end, projecting laterally from said torsionally elongated central body, of a first threaded rod, a nut being further screwed onto said end of said first threaded rod so as to ensure the tightening of said lower riser against said torsionally elongated central body.

[0038] Each said interfacing device may in particular include a lower interfacing element consisting of a plate fixed by screwing against the lower part of the inner end edge of a said respective support arm so as to present two portions projecting longitudinally respectively at the front and rear of this arm and each crossed at the level of a respective orifice by an end, projecting laterally from said torsionally elongated central body, of a second respective threaded rod, each said projecting portion being further held fixedly sandwiched between two nuts screwed onto said end of said second threaded rod.

[0039] In order to prevent the coming together of the adjacent lateral support arms from two said adjoining monobloc elements and therefore the deformation by crushing of the supporting vaults of these adjoining monobloc elements by compression of their opposite edges caused by the bending under its own weight of said elongated central body of torsion, said adjacent lateral support arms from two said adjoining monobloc elements are fixedly connected to each other by at least one longitudinal connecting reinforcement.

[0040] According to advantageous construction characteristics, said parabolic cylindro-reflector is advantageously made up of several thin reflective slabs with a parabolic cross-section.

[0041] For ease of assembly of the solar collector, said reflective slabs extend over the same longitudinal depth as said arches supporting said monobloc elements against which these reflective slabs are fixed by gluing before the formation of said sections by assembling these monobloc elements two by two.

[0042] Due to the technical difficulties associated with the manufacture of very large reflective slabs, the upper surface of said supporting vault of each monobloc element is preferably covered by at least two reflective slabs joined two by two along their longitudinal edges.

[0043] To allow adjustment of the reflector's orientation relative to the sun, the support structure is advantageously mounted to pivot around a longitudinal axis parallel to the linear focus of the parabolic cylindro-reflector by means of two load-bearing pillars arranged near the two longitudinal ends of this support structure. Furthermore, and to ensure the solar collector is anchored to the ground without resorting to buried foundations that contribute to soil sealing and impermeability, each of the load-bearing pillars is advantageously provided at its lower end with at least one anchoring pad made of a mineral material designed to rest on the ground.

[0044] Finally, the material of mineral origin is preferably concrete.

[0045] The invention also relates, in a second aspect, to a solar collection assembly formed of at least one alignment of several such parabolic-cylindrical solar collectors.

[0046] The description of the invention will now be continued by a detailed description of an example embodiment, given below by way of illustration but not limitation, with reference to the attached drawings, on which:

[0047] - Figure 1 represents a perspective view of a solar collection assembly formed of two parallel alignments of several parabolic-cylindrical solar collectors according to the invention;

[0048] - Figure 2 is a perspective view of a parabolic cylindrical solar collector according to the invention;

[0049] - Figure 3 represents an enlarged perspective view of one of the two pivoting articulation zones of the support structure of the cylindrical-parabolic solar collector of Figure 2;

[0050] - Figure 4 is a perspective view of one of the monobloc elements made of mineral material that comprise the trough of the support structure of the cylindrical-parabolic solar collector of Figure 2;

[0051] - Figure 5 represents an exploded perspective view of the support structure of the parabolic-cylindrical solar collector of Figure 2;

[0052] - Figure 6 is an enlargement of detail VI from figure 5;

[0053] - Figure 7 represents a perspective view of one of the connecting elements fixedly linking two symmetrical monobloc elements opposite the trough of the support structure of the cylindrical-parabolic solar collector of Figure 2;

[0054] - Figure 8 is an enlargement of the interface area between the lower end portion of a lateral branch of a connecting member and a lateral side of the elongated central torsion body of the cylindrical-parabolic solar collector of Figure 2;

[0055] - Figure 9 represents an enlargement in perspective of the external interface area between two adjoining monobloc elements of the trough of a cylindrical-parabolic solar collector conforming to a variant embodiment of the invention, a longitudinal connecting reinforcement fixedly linking to each other the adjacent lateral support arms coming from these two monobloc elements;

[0056] - Figure 10 is a section view of the interface zone of Figure 9 crossing this longitudinal connecting reinforcement;

[0057] - Figure 11 represents an enlargement of detail XI from figure 10;

[0058] - Figure 12 is a perspective enlargement of the interface areas between two monobloc elements of the same section of the trough and the elongated central torsion body of a cylindrical-parabolic solar collector conforming to another embodiment of the invention;

[0059] - Figure 13 represents a cross-sectional view taken along a plane passing through one of the interface zones of Figure 13; and

[0060] Figure 14 is a perspective view of the upper interface element of an interface device between a lateral support arm of a monobloc element and the elongated central torsional body. Figure 1 is a general view of a solar collection assembly E formed of two parallel alignments, each consisting of six parabolic-cylindrical solar collectors 1 according to the invention.

[0061] Intended for example to produce steam which can then be used to generate electricity using a steam turbine or to provide heat to industrial processes or heating systems, the solar collection assembly E includes pipes, not shown, fluidly connecting the absorber tubes of the different solar collectors 1 and allowing the heated heat transfer fluid to be transported to a steam production system.

[0062] The number of alignments and / or the number of parabolic-cylindrical solar collectors 1 of each alignment of such a solar collection set E will obviously vary depending on the desired solar energy production capacity.

[0063] Figure 2 represents one of the parabolic-cylindrical solar collectors 1 of this assembly E.

[0064] With respect to this solar collector 1, we define an orthogonal coordinate system XYZ comprising three axes perpendicular to each other in pairs, namely:

[0065] - an X axis, defining a longitudinal, horizontal direction, parallel to the linear focus of this solar collector 1;

[0066] - a Y-axis, defining a transverse direction, perpendicular to the linear focus of this solar collector 1 and which, together with the X-axis, defines a horizontal XY plane parallel to the ground, and

[0067] - a Z axis, defining a vertical direction perpendicular to the XY plane.

[0068] In the remainder of this description and with reference to the coordinate system defined above, the terms "longitudinal" or "longitudinally" will refer to a direction parallel to the X-axis, the terms "transverse" or "transversely" will refer to a direction parallel to the Y-axis, and the terms "vertical" or "vertically" will refer to a direction parallel to the Z-axis. Furthermore, the terms "upper" and "lower" will be used to specify the relative position of certain elements with respect to the orientation of the Z-axis.

[0069] The terms "external" and "internal" will be used to define the relative position of an element with reference to the vertical longitudinal plane of symmetry of the solar collector 1. The element closest to this plane will thus be described as internal, as opposed to the other element further from this same plane, which will be described as external.

[0070] Finally, the term "substantially" indicates that a slight deviation from a predetermined nominal orientation is permitted, while remaining within the scope of the invention. For example, "substantially parallel" indicates that a deviation of approximately 10° to 20° from a strictly parallel orientation is permitted within the scope of the invention.

[0071] With reference to this figure 2, the parabolic-cylindrical solar collector 1 includes a parabolic-cylindrical reflector 100 having a linear focus extending along a longitudinal direction, this reflector 100 being able to reflect and concentrate the solar light rays striking it on its linear focus.

[0072] This solar collector 1 also includes an absorber tube 200 extending longitudinally along the linear focal point of the reflector 100, to which it is attached, in order to receive the light rays captured and reflected by the latter. Inside this absorber tube 200, a heat transfer fluid, typically composed of oil or water, circulates and is designed to absorb the heat generated by the light rays striking this tube.

[0073] This solar collector 1 further comprises a support structure 300 supporting the reflector 100 and the absorber tube 200, this support structure 300 essentially made of mineral material being mounted pivotally around a longitudinal axis A parallel to the linear focus of the parabolic cylindro-reflector 100 by means of two supporting pillars 400 arranged near its two longitudinal ends.

[0074] In the following description, a material of mineral origin means any material based on ores, rocks, or natural minerals. For the purposes of this invention, such a material of mineral origin is preferably concrete, but could also be a composite material made of stone and carbon fibers (for example, marketed under the CFS® brand by TechnoCarbon) or any other material of mineral origin meeting the material requirements of the invention. For such a composite material, stone can be replaced by other minerals, such as glass, ceramics, or recycled materials.

[0075] It will be noted that such a constitution essentially in mineral material of the support structure 300 ensures the solar collector 1 according to the invention a significantly greater rigidity compared to solar collectors with a conventional metal support structure, which allows it to withstand higher wind speeds (on the order of 135 km / h against 40 km / h for solar collectors with a metal support structure).

[0076] Each of the two load-bearing pillars 400 comprises two metal uprights 410 extending diagonally from their lower ends towards each other and meeting at their upper ends, thus forming a V with its point facing upwards. Each load-bearing pillar 400 also comprises a connecting metal bar 420 extending transversely between the two uprights 410 and whose two ends are rigidly fixed to these uprights 410.

[0077] As can be seen more clearly in Figure 3, each load-bearing pillar 400 further includes a metal support plate 430 surmounting the upper ends of the two uprights 410 and extending substantially horizontally.

[0078] According to unrepresented embodiment variants, the 400 supporting pillars may have a different conformation (for example in the shape of a pylon or tripod) and / or be made of a non-metallic material (for example concrete).

[0079] In order to ensure the anchoring to the ground of the solar collector 1, the supporting pillars 400 are each further provided at their lower end with at least one anchoring footing made of mineral material 440 intended to rest on the ground S. In this case, each supporting pillar 400 comprises two said anchoring footings made of mineral material 440 each sealed to the lower end of a corresponding post 410.

[0080] Making it possible to avoid the need for buried foundations which contribute to the artificialization and impermeability of the soil, such a configuration with simple footings made of mineral material above ground 440 is made possible thanks to the intrinsic stability of the support structure 300 conferred naturally by its constitution essentially in mineral material.

[0081] The height of the supporting pillars 400 defining the distance between the ground S and the pivot axis A of the support structure 300 (and therefore of the reflector 100) will be advantageously defined so as to allow the latter to pivot through 360° in order to follow the sun in its daily course and thus capture solar radiation under optimal conditions.

[0082] With further reference to Figure 2, the support structure 300 of the solar collector 1 comprises an elongated central torsional body of mineral material 310 oriented longitudinally and therefore parallel to the linear focus of the parabolic cylindro-reflector 100.

[0083] As illustrated by Figure 3, the pivoting articulation of the support structure 300 vis-à-vis the two load-bearing pillars 400 is advantageously ensured by means of two cylindrical metal pins 311 projecting from the two longitudinal ends of the elongated central torsion body 310 and each cooperating with a respective rotating joint 450 mounted at the top of a corresponding load-bearing pillar 400.

[0084] Each pin 311 extends in this case from a respective metal plate 312 fixedly attached by screwing onto a longitudinal end of the elongated central torsion body 310.

[0085] As can be seen in Figure 3, the position of each rotary joint 450 is advantageously finely adjustable in height over a predetermined range by means of a mechanical adjustment device 460, interposed between it and the support plate 430 of the corresponding load-bearing pillar 400. This adjustment device 460 comprises, in this case, two threaded rods 461 spaced transversely apart and passing through holes formed in the support plate 430, and on each of which two locking nuts 462, 463 are screwed, sandwiching this support plate 430. The position of the rotary joint 450 can thus be adjusted by varying the position of the locking nuts 462, 463 along the threaded rods 461.

[0086] One of these two cylindrical pins 311 may advantageously be coupled to a motorized device so as to control the rotation of the support structure 300 carrying the parabolic cylindro-reflector 100. This motorized device may, for example, include a DC motor or stepper motor mounted coupled directly to one of the pins 311 or via rack and pinion or chain and gear transmission means mainly for reasons of reliability and mechanical efficiency.

[0087] Again with reference to Figure 2, the support structure 300 also includes a trough 330 having a concave cylindro-parabolic upper surface supporting the reflector 100.

[0088] The trough 330 consists of several sections T joined longitudinally to each other and each comprising a pair of two identical monobloc elements in mineral material M extending symmetrically opposite each other on either side of the elongated central torsional body 310.

[0089] In the embodiment illustrated in the figures, trough 330 consists of four identical T sections with a transverse span of approximately six meters and extending longitudinally over approximately three meters, so that this trough 330 extends over a total length of about twelve meters.

[0090] In order for these monobloc M elements to exhibit excellent tensile and flexural strength qualities, they will advantageously be made of high-performance reinforced or prestressed concrete, advantageously equipped with stainless steel or galvanized steel reinforcement to protect it from corrosion.

[0091] To avoid any risk of corrosion, it is also possible to make these monobloc M elements in fiber-reinforced concrete, although this may negatively impact their cost price as well as their flexural strength.

[0092] As illustrated by Figure 4, which shows one of them in perspective, each of the monobloc elements M comprises a support arch 331 having a concave upper surface with a semi-parabolic profile and whose thickness advantageously increases progressively between its inner end located at the level of the elongated central torsional body 310 (where this thickness is for example between 30 and 50 millimeters) and its free outer end (where this thickness is for example between 70 and 100 millimeters).

[0093] Each monobloc element M also includes several (in this case, two) curved lateral support arms 332 extending parallel in pairs along vertical transverse mean planes from the underside of the support arch 331 and over the entire transverse width of this support arch 331, tapering radially in a progressive manner between their inner and outer ends.

[0094] It should also be noted that the monobloc elements M advantageously present a median vertical transverse plane of symmetry, so as to allow the manufacture of the trough 330 from a single reference of such a monobloc element M (all the elements M constituting the trough 330 being thus strictly identical).

[0095] In order to ensure effective support of the supporting vault 331 and to prevent its sagging, the lateral support arms 332 of the same monobloc element M are spaced longitudinally in pairs with the same predetermined spacing e1 preferably less than 2 meters and advantageously between 1.60 and 1.90 meters.

[0096] For the same reasons, the lateral support arms 332 front and rear of the same monobloc element M are respectively spaced longitudinally from the front and rear ends of its support arch 331 by the same spacing e2 preferably less than 1 meter and advantageously between 0.5 and 0.8 meters.

[0097] According to alternative embodiments not shown, the number of lateral support arms 332 may vary in particular depending on the longitudinal depth of the monobloc elements M, this number being advantageously between two and five.

[0098] As illustrated by the exploded view in Figure 5, each section T also includes several (in this case, two) inverted U-shaped connecting members O fixedly linking each of the internal end edges opposite two lateral support arms 332 of its two monobloc elements M, and each being fixedly mounted overlapping on the elongated torsional central body 310 as shown in Figure 2.

[0099] With reference to the enlargement of Figure 6 and Figure 7, each connecting member O comprises a top plate 334 and two substantially parallel lateral arms 335 each fixed by screwing against the inner end edge of a respective lateral support arm 332 of a corresponding monobloc element M.

[0100] More specifically, and as can be clearly seen in this figure 6, the attachment of each lateral branch 335 of a connecting member O to a respective lateral support arm 332 is achieved by means of at least two screws V1 (advantageously of type M24) spaced vertically apart, each passing through a respective orifice 335A (see figure 7) provided in this lateral branch 335 and screwing into the internal thread of a corresponding anchor sleeve D1 sealed in the original mineral material forming this lateral support arm 332 (these sleeves D1 being represented by dashed lines in figure 8).

[0101] To optimize the stability of the connection between the two monoblock elements M of the same section T, all the support arms 332 of the two monoblock elements M constituting this section T are advantageously connected in pairs by such a respective connecting member O. In order to facilitate the lifting and movement of the monoblock elements M to the assembly station of the sections T, these monoblock elements M may advantageously include additional anchoring sockets D2, shown as dashed lines in Figure 4, sealed in the original mineral material (in particular near the inner and outer end edges of at least one of their lateral support arms 332) and onto which anchoring members (for example, of the angle bracket or ring type) not shown can be fixedly screwed.

[0102] With further reference to Figure 6, the summit plate 334 of each connecting member O is screwed onto the top of the elongated central torsional body 310, by means of at least one screw V2 (advantageously of type M24) passing through a respective orifice 334A (see Figure 7) provided in the center of this plate 334 and screwing into the internal thread of a corresponding anchor sleeve D3 sealed in the original mineral material forming this elongated central torsional body 310.

[0103] To facilitate the lifting and movement of the T sections to their assembly station on the elongated central torsion body 310, the top plate 334 of each connecting member O may advantageously have at least one threaded hole (not shown) allowing a respective lifting ring to be fixedly screwed into it. Advantageously, this top plate 334 will have two such threaded holes arranged symmetrically on either side of its opening 334A.

[0104] As can be seen in Figure 8, each of the lateral branches 335 of a connecting member O has a lower end portion 336 projecting below the lateral support arm 332 on which it is fixed.

[0105] These lower end portions 336 of the lateral branches 335 of each connecting member O are each screwed onto a respective lateral side of the torsionally elongated central body 310 by means of at least one screw V3 (advantageously of type M16) passing through a respective orifice 336A provided in this lower end portion 336 and screwing into the internal thread of a corresponding anchoring sleeve D4 sealed in the original mineral material forming this torsionally elongated central body 310.

[0106] In order to ensure, when placing a section T on the extended torsional central body 310 with overlap, the correct alignment of the orifices 336A of the connecting members O of this section T with the internal threads of the corresponding anchoring sleeves D4, it will be noted that these orifices 336A advantageously open onto the lower end edge of the lateral branches 335 of the connecting members O so as to allow the shanks of the screws V3, previously partially screwed into these internal threads of the sleeves D4, to come and be inserted into these orifices 336A.

[0107] In the months following the commissioning of the collector 1, the phenomenon of creep of the mineral material (i.e. its ability to deform due to certain permanent mechanical stresses to which it is subjected, in particular its weight) risks causing a slight sagging of the monobloc elements M, generating a notable decrease in the capture by the absorber tube 200 of the light rays reflected by this reflector 100, the solar collector 1 advantageously includes adjustment means allowing fine readjustment of the inclination of each of these monobloc elements M with respect to the elongated central torsional body 310.

[0108] With reference to figure 8, these adjustment means comprise, at each interface zone between the lower end portion 336 of a lateral branch 335 of a connecting member O and a lateral side of the torsionally elongated central body 310, at least one screw V4 (advantageously of type M8) screwed into a respective thread 336B provided on this lower end portion 336 (see figure 7) and whose free internal end of its protruding portion through this thread rests against a corresponding lateral face of this torsionally elongated central body 310.

[0109] As illustrated in this figure 8, these adjustment means preferably comprise, at each said interface zone, two screws V4 screwed into two respective threads 336B provided on the lower end portion 336 of the respective lateral branch 335 of a corresponding connecting member O, advantageously symmetrically with respect to the orifice 336A.

[0110] In order to prevent the free ends of the shanks of the screws V4 from bearing directly against the mineral origin material and risking damage to it, the two lateral faces of the elongated central torsion body 310 have, at each interface zone, a corresponding rectangular metal contact plate 314 sealed in the mineral origin material and against which rest the free end(s) of the screw(s) V4 opening through the thread(s) 336B provided on the lower end portion 336 of a corresponding lateral branch 335.

[0111] It will be noted in support of figure 8 that these plates 314 each have an orifice aligned with the internal thread of a corresponding anchor sleeve D4 so as to allow the screws V3 to be screwed into these threads.

[0112] To readjust the inclination of a monobloc element M, the operator in charge of this operation must first partially unscrew the screws V3. He must then adjust the screwing of the screws V4 so as to increase the depth of their protruding portions through the threads 336B of the lower end portions 336 of the respective lateral branches 335 of the corresponding connecting members O, which will have the effect of causing the elastic pivoting separation of these lateral branches 335 (and therefore of the monobloc element M fixed to them) with respect to the elongated torsional central body 310.

[0113] Given the size of the M monobloc elements, it is easy to understand that a simple increase of a few millimeters in the depth of the portions of the V4 screws protruding through the 336B threads will be enough to cause a variation in the deflection height of the corresponding M monobloc element over several centimeters.

[0114] In order to lock this new positioning of the lateral branches 335 (and therefore of the monobloc elements M attached to them) vis-à-vis the elongated central torsion body 310 to prevent them from moving further apart due to the weight of these monobloc elements M when the solar collector 1 adopts a more inclined configuration relative to the horizontal, the operator will finally have to screw the screws V3 so that their heads come to rest against the perimeter of the corresponding orifices 336A.

[0115] In order to ensure sufficient rigidity to prevent bending during the operations of placing the T sections on the elongated central torsion body 310 and due to the significant stresses exerted on their lateral branches 335 by the monobloc elements M that these branches 335 connect, the connecting members O are advantageously each made from three metal strips (for example in steel) welded to each other and having a thickness of at least 10 millimeters and preferably between 15 and 25 millimeters.

[0116] In order to limit the driving torque required to rotate the sub-assembly consisting of the support structure 300 and the parabolic cylindro-reflector 100, the elongated central torsional body 310 will be advantageously configured so that the center of gravity of this rotating sub-assembly 100, 300 is located at the pivot axis A.

[0117] In this case and as illustrated in particular by figures 2 and 5, the elongated central torsion body 310 is thus in the form of a longitudinal beam made of mineral material with an inverted T-shaped cross-section, the head 310A of which is oriented opposite to the trough 330 forms a counterweight which brings the center of gravity of the rotating sub-assembly 100, 300 to the level of this pivot axis A.

[0118] According to unrepresented embodiment variants, the elongated central torsional body 310 of the support structure 300 can be shaped differently, for example taking the form of a solid or hollow beam with a triangular section or in the shape of an angular sector of a circle.

[0119] As illustrated in Figure 5, the parabolic-cylindrical reflector 100 consists of a matrix array of nm thin reflective tiles 110 with a parabolic cross-section, arranged in n longitudinal lines parallel to the linear focus of this reflector 100 and m transverse columns. The adjective "thin" applied to the reflective tiles 110 should be interpreted in this case to mean that their thickness is sufficiently small relative to their length and width to give them a degree of flexibility, allowing them to conform perfectly, when cold and simply due to gravity, to the concave parabolic-cylindrical upper surface of the trough 330 of the support structure 300.

[0120] Each reflective slab 110 advantageously comprises a transparent substrate, preferably made of glass due to its excellent light transmission combined with a controlled cost price, and covered on its convex underside with a reflective layer, for example silver.

[0121] These reflective 110 tiles may also include at least one protective layer, including a copper or tin layer applied against the reflective layer.

[0122] For ease of assembly of the solar collector 1, the reflective slabs 110 extend over the same longitudinal depth of approximately three meters as that of the supporting arches 331 of the monobloc elements M against which these reflective slabs are fixed by gluing (for example via epoxy or polyurethane glue or even via double-sided adhesives) before the formation of the sections T by the assembly of these monobloc elements M two by two via the connecting members O.

[0123] Due to the technical difficulties associated with the manufacture of very large reflective slabs, the upper surface of the supporting vault 331 of each monobloc element M is advantageously covered by at least two reflective slabs 110 joined two by two by their longitudinal edges.

[0124] In this case, and as illustrated by Figures 2 and 5, the upper surface of each supporting vault 331 is covered by three reflective slabs 110, each advantageously having a width between 0.9 and 1.25 meters. It should also be noted that the width of these slabs 110 advantageously increases with their transverse spacing relative to the elongated central torsional body 310.

[0125] The reflector 100 as a whole is thus made up of twenty-four reflective slabs 110 arranged in six longitudinal lines and four transverse columns.

[0126] According to an alternative embodiment illustrated by figures 9 to 11, the adjacent lateral support arms 332 originating from two adjoining monobloc elements M are fixedly connected to each other by at least one longitudinal connecting reinforcement 340.

[0127] The presence of at least one such longitudinal connecting reinforcement 340 thus makes it possible to prevent the coming together of these lateral support arms 332 and therefore the deformation by crushing of the supporting vaults 331 of two adjoining monobloc elements M by compression of their opposite curved edges caused by the bending under its own weight of the elongated central torsional body 310.

[0128] These longitudinal connecting reinforcements 340 are advantageously positioned closer to the free external ends of the lateral support arms 332 than to their internal ends attached to the elongated central torsional body 310, so as to limit the compressive stresses exerted on the latter and the moment transmitted to this elongated central torsional body 310.

[0129] As illustrated by Figure 9, and because the thinness of the lateral support arms 332 at their external ends does not allow for a sufficiently high-quality screw fixing, these longitudinal connecting reinforcements 340 are preferably spaced from these external ends at a distance greater than or equal to a predetermined minimum value, for example between two hundred and four hundred millimeters.

[0130] With reference to Figure 10, each connecting reinforcement 340 is formed in this case by a hollow metal profile 341 of square section provided at each of its ends with a metal nut 342. Each nut 342 is advantageously welded or press-fitted onto a corresponding end of the profile 341.

[0131] As can be clearly seen in Figure 11, the attachment of each end of a connecting reinforcement 340 to a corresponding lateral support arm 332 is ensured by means of a screw V5 (advantageously of type M16) passing successively through a metal washer 343 and a longitudinal through hole 332A provided in this lateral support arm 332, then screwing itself onto the nut 342 located at this end of the connecting reinforcement 340.

[0132] In order to avoid direct contact between the mineral material constituting the lateral support arm 332 and the metal elements constituting the nut 342 and the washer 343, two shims 344 made of elastomeric material (for example neoprene) are advantageously interposed respectively, between the washer 343 and the lateral support arm 332, and between this lateral support arm 332 and the nut 342.

[0133] The addition of such shims 344 made of elastomeric material thus makes it possible to protect the lateral support arm 332 against localized crushing and long-term mechanical deterioration.

[0134] According to another embodiment illustrated by figures 12 to 14, the support structure 300 is devoid of a connecting element O linking the two monobloc elements M of each section T.

[0135] Each monobloc element M of a section T of the trough 330 is mounted independently on the elongated torsional central body 310 by means of several interface devices D each ensuring the attachment of a respective lateral support arm 332 of this monobloc element M to this elongated torsional central body 310.

[0136] Each interface device D comprises a stepped profile upper interface element 350, shown alone in Figure 14, and consisting of an upper riser 351 in which an opening 351A is provided, a step 352 and a lower riser 353 parallel to the upper riser 351 and in which an inverted U-shaped notch 353A is provided opening onto its lower edge. As illustrated by Figures 12 and 13, this upper interface element 350 is fixed against the upper part of the inner end edge of a respective support arm 332 by means of a screw V6 (advantageously of type M24) passing through the orifice 351A provided in its upper riser 351 and screwing into the internal thread of a corresponding anchor sleeve D5 sealed in the original mineral material forming this lateral support arm 332.

[0137] This upper interface element 350 is also fixed to the elongated torsional central body 310 by means of its lower riser 353 which is mounted overlapping, via its notch 353A, on one end, projecting laterally from said elongated torsional central body 310, of a first threaded rod TF1 (advantageously of type M24) partially embedded in the mineral material forming this elongated torsional central body 310 and projecting laterally on either side of the latter, a nut E1 being then screwed onto this end of this first threaded rod TF1 so as to ensure the tightening of this lower riser 353 against this elongated torsional central body 310.

[0138] It should be noted in this regard that each threaded rod TF1, passing through the elongated central torsional body 310 from one end to the other and receiving at its two ends two support arms 332 belonging to two distinct monobloc elements M of the same section T, makes it possible to ensure better mechanical continuity between these two support arms 332. Such a configuration also reduces the stresses localized in the elongated central torsional body 310, this threaded rod TF1 being able to take up the tensile forces continuously over its entire length.

[0139] Each interface device D also includes a lower interface element consisting of a rectangular plate 360 ​​fixed against the lower part of the inner end edge of a respective support arm 332 so as to present two portions 361, 362 projecting longitudinally respectively at the front and rear of this same arm 332, this fixing being achieved by means of a screw V7 (advantageously of type M24) passing through a central hole provided in this plate 360 ​​and screwing into the internal thread of a corresponding anchor sleeve D6 sealed in the original mineral material forming this lateral support arm 332.

[0140] This lower interface element 360 is also fixed to the elongated torsional central body 310 by means of its two projecting portions 361, 362, each of which is traversed at a respective orifice by an end, projecting laterally from said elongated torsional central body 310, of a second respective threaded rod TF2 (advantageously of type M16) screwed into the internal tapping of a corresponding anchoring sleeve D7 sealed in the original mineral material forming this elongated torsional central body 310, each projecting portion 361, 362 being further held fixedly sandwiched between two nuts E2 screwed onto this end of this second threaded rod TF2.Such a fixing system of the lower interface element 360 to the torsionally elongated central body 310 allows, if necessary and in particular to compensate for the slight deformation of the support arms 320 caused by the creep phenomenon, to finely readjust the inclination of the curved support arms 120 of each monobloc element M with respect to the torsionally elongated central body 310 by simply varying the positioning of the nuts E2 along the protruding ends of the threaded rods TF3.

[0141] According to variants not shown and depending in particular on the transverse span of the solar collector, the number of reflective slabs 110 covering each support vault 331 could differ, for example being equal to one, two or four.

[0142] Many embodiments are of course conceivable and it is recalled in this regard that the present invention is not limited to the embodiments described and represented, but also encompasses all the execution variants within the reach of a person skilled in the art.

Claims

26 DEMANDS 1. Cylindrical-parabolic solar collector (1) comprising: - a parabolic cylindrical reflector (100) having a linear focus extending along a longitudinal direction, said reflector (100) being capable of reflecting and concentrating the solar light rays striking it onto said linear focus; and - a support structure (300) supporting said reflector (100) and comprising a central torsionally elongated body of mineral material (310) oriented longitudinally and a trough (330) having a concave cylindro-parabolic upper surface supporting said reflector; characterized in that said trough is made up of several sections (T) joined longitudinally to each other and each comprising a pair of two monobloc elements of mineral material (M) extending symmetrically opposite each other on either side of said central torsionally elongated body (310), each said monobloc element (M) comprising a support arch having a concave upper surface with a semi-parabolic profile, as well as several curved lateral support arms (332) extending from the lower face of said support arch (331) and over the entire transverse width of this support arch (331).

2. Solar collector according to claim 1, characterized in that each said section (T) also comprises several connecting members (O) fixedly connecting each of the internal end edges opposite two said lateral support arms (332) of its two said monobloc elements (M), and each being fixedly mounted overlapping on said elongated torsional central body (310).

3. Solar collector according to claim 2, characterized in that all said lateral support arms (332) of the two said monobloc elements M constituting a single said section (T) are connected two by two by a respective said connecting member (O).

4. Solar collector according to one of claims 2 or 3, characterized in that each said connecting member (O) with inverted U profile comprises a top plate (334) and two substantially parallel lateral arms (335) each fixed by screwing against the inner end edge of a respective lateral support arm (332) of a corresponding monobloc element (M).

5. Solar collector according to claim 4, characterized in that each of said lateral branches (335) of said connecting member (O) has a lower end portion (336) projecting below said lateral support arm (332) on which it is fixed.

6. Solar collector according to claim 5, characterized in that said lower end portions (336) of said lateral branches (335) of each said connecting member (O) are each screwed onto a respective lateral side of said torsionally elongated central body (310) by means of at least one screw (V3) passing through a respective orifice (336A) provided in this lower end portion (336) and screwing into the internal thread of a corresponding anchoring sleeve (D4) sealed in the mineral material of origin forming this torsionally elongated central body (310).

7. Solar collector according to claim 68 characterized in that it comprises adjustment means allowing for fine readjustment the inclination of each of said monobloc elements (M) with respect to said torsionally elongated central body (310), said adjustment means comprising, at the level of each interface zone between said lower end portion (336) of said lateral branch (335) of said connecting member (O) and a lateral side of said torsionally elongated central body (310), at least one screw (V4) screwed into a respective thread (336B) provided on this lower end portion (336) and whose free internal end of its protruding portion through this thread (336B) rests against a corresponding lateral face of this torsionally elongated central body (310).

8. Solar collector according to claim 7, characterized in that the two lateral faces of said torsionally elongated central body (310) have, at the level of each interface zone, a corresponding metal contact plate (314) sealed in the mineral origin material and against which rest the free end(s) of said screw(s) (V4) opening through the thread(s) (336B) provided on said lower end portion (336) of a said corresponding lateral branch (335).

9. Solar collector according to claim 1, characterized in that each said monobloc element (M) of a said section (T) is mounted independently on said torsionally elongated central body (310) by means of several interface devices (D) each ensuring the attachment of a respective lateral support arm (332) of this monobloc element (M) to this torsionally elongated central body (310).

10. Solar collector according to claim 9, characterized in that each said interfacing device (D) comprises a stepped profile upper interfacing element (350) consisting of a riser 29 upper (351) fixed by screwing against the upper part of the inner end edge of a respective support arm (332), of a step (352) and of a lower riser (353) in which is provided an inverted U-shaped notch (353A) opening onto its lower edge, said lower riser (353) being mounted overlapping via said notch (353A) on one end, projecting laterally from said torsionally elongated central body (310), of a first threaded rod (TF1), a nut (E1) being further screwed onto said end of said first threaded rod (TF1) so as to ensure the tightening of said lower riser (353) against said torsionally elongated central body (310).

11. Solar collector according to any one of claims 9 or 10, characterized in that each said interfacing device (D) comprises a lower interfacing member consisting of a plate (360) fixed by screwing against the lower part of the inner end edge of a respective support arm (332) so as to have two portions (361, 362) projecting longitudinally respectively at the front and rear of this arm (332) and each traversed at the level of a respective orifice by an end, projecting laterally from said elongated torsional central body (310), of a respective second threaded rod (TF2), each said projecting portion (361, 362) being further held fixedly sandwiched between two nuts (E2) screwed onto said end of said second threaded rod (TF2).

12. Solar collector according to any one of claims 1 to 11, characterized in that the adjacent lateral support arms (332) originating from two said adjoining monobloc elements (M) are fixedly connected to each other by at least one longitudinal connecting reinforcement (340). 30 13. Solar collector according to any one of claims 1 to 12, characterized in that said parabolic cylindrical reflector (100) is made up of several thin reflective slabs (110) with a parabolic cross-section.

14. Solar collector according to claim 13, characterized in that said reflective slabs (110) extend over the same longitudinal depth as said support vaults (331) of said monobloc elements (M) against which these reflective slabs (110) are fixed by gluing before the formation of said sections (T) by the assembly of these monobloc elements (M) two by two.

15. Solar collector according to claim 14, characterized in that the upper surface of said support vault (331) of each monobloc element (M) is covered by at least two reflective slabs (110) joined two by two by their longitudinal edges.

16. Solar collector according to any one of claims 1 to 15, characterized in that said support structure (300) is pivotally mounted about a longitudinal axis (A) parallel to said linear focus of said parabolic cylindro-reflector (100) by means of two supporting pillars (400) arranged near its two longitudinal ends.

17. Solar collector according to claim 16, characterized in that said supporting pillars (400) are each provided at their lower end with at least one anchoring base (440) made of mineral material intended to rest on the ground. 31 18. Solar collector according to any one of claims 1 to 17, characterized in that the mineral-based material is concrete.

19. Solar collection assembly formed of at least one alignment of several parabolic trough solar collectors according to any one of claims 1 to 18.

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