Parabolic trough solar collector

Abstract

The invention relates to a parabolic-cylindrical solar collector comprising: - a parabolic-cylindrical reflector (100) having a linear focus extending along a longitudinal direction, said reflector (100) being able to reflect and concentrate the solar light rays striking it on said linear focus; and - a support structure (300) supporting said reflector (100) and comprising a central torsionally elongated concrete body (310) oriented longitudinally and a trough (330) having a concave parabolic-cylindrical upper surface supporting said reflector (100); characterized in that said trough (330) is made up of several sections (T) joined longitudinally to each other and each comprising a pair of two monobloc concrete elements (M) extending symmetrically opposite each other on either side of said central torsionally elongated body (310). Figure to be published with the abbreviation: Fig. 5

Description

Title of the invention: Cylindrical-parabolic solar collector technical field

[0001] The present invention relates to the field of solar energy capture and more particularly to a parabolic-cylindrical type solar collector. Previous technique

[0002] 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 has many advantages.

[0003] Among the various technological solutions aimed at capturing part 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.

[0004] In particular, cylindrical-parabolic type collectors are known which include a cylindrical-parabolic reflector focusing the captured light rays towards an absorber tube arranged along the linear focus of this reflector.

[0005] 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 to industrial processes or heating systems.

[0006] The main advantage of parabolic-cylindrical collectors lies in their ability to concentrate sunlight on a narrow linear area, which allows for higher temperatures and better solar energy conversion efficiency.

[0007] Furthermore, parabolic trough collectors can be used in a modular manner and combined to form large-scale solar collection assemblies capable of producing a significant amount of electricity or heat.

[0008] Such a cylindrical-parabolic type collector classically comprises a support structure supporting the absorber tube and 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.

[0009] As disclosed, for example, by document WO 2013 / 084016 A1, this support structure generally comprises a central torsionally elongated 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 stresses it undergoes because of its own mass and external forces such as wind.

[0010] Made of galvanized steel or aluminium, this elongated central torsion body is generally in the form of a cylindrical tube or a tubular frame.

[0011] Such a support structure also classically comprises 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.

[0012] Made for example from welded metal tubes or from a stamped sheet metal side, these lateral support arms make it possible to distribute the load and rigidity evenly along the surface of the reflector.

[0013] These metal support structures are generally mounted articulated 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.

[0014] Their insufficient rigidity, however, makes them particularly sensitive to wind, so that solar collectors with such a metallic 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.

[0015] We also know from document DE 31 33 906 Al, 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.

[0016] Such a concrete construction of the support structure ensures significantly greater rigidity compared to metal support structures, which allows it to withstand significantly higher wind speeds.

[0017] Unfortunately, the construction of such a monolithic concrete support structure proves particularly complex and costly. Furthermore, due to its dimensions and mass, this support structure cannot be transported and must therefore be built on site.

[0018] Furthermore, in the months following its completion, the curing 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. Description of the invention

[0019] The present invention therefore aims to remedy at least partially the aforementioned drawbacks.

[0020] To this end, it proposes a parabolic-cylindrical solar collector comprising: - 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 - a support structure supporting said reflector and comprising a longitudinally oriented elongated central torsional concrete body and a trough having a concave cylindro-parabolic upper surface supporting said reflector.

[0021] According to the invention, said trough is made up of several sections longitudinally joined to each other and each comprising a pair of two monobloc concrete elements extending symmetrically opposite each other on either side of said elongated central torsion body.

[0022] Such a construction of the trough supporting the reflector from monobloc concrete elements 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 location of the solar collector installation.

[0023] Moreover, such a constitution makes it easy to vary the longitudinal depth of the solar collector by simply modulating the number of sections made from the same monoblock concrete elements.

[0024] In order to obtain an optimal compromise between its rigidity and its mass, each said monobloc element advantageously comprises a support arch having a concave upper surface with a semi-parabolic profile, as well as several curved lateral support arms extending from the lower face of said support arch and over the entire transverse width of said support arch.

[0025] Each said section also preferably comprises several connecting members 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 torsional central body.

[0026] In order to optimize the stability of the connection between the two monobloc elements of the same section, all 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.

[0027] 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 arms each fixed by screwing against the inner end edge of a respective lateral support arm of a corresponding monobloc element.

[0028] In order to ensure optimal assembly quality, the fixing 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 concrete forming this lateral support arm.

[0029] Also for reasons of quality and ease of assembly, the top plate of each said connecting member 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 concrete forming said torsionally elongated central body.

[0030] 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.

[0031] In order to secure the attachment of the sections to the elongated central torsional body, said lower end portions of said lateral branches of each said connecting member are advantageously screwed each onto a respective lateral side of said elongated central torsional 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 anchor sleeve sealed in the concrete forming this elongated central torsional body.

[0032] In order to compensate for the consequences of the phenomenon of the fineness of the concrete forming the monobloc elements, said collector preferably includes adjustment means allowing to fine readjust the inclination of each of said monobloc elements with respect to said central torsionally elongated body, said adjustment means comprising, at the level of each interface zone between said lower end portion of a said lateral branch of a said connecting member and a lateral side of said central torsionally elongated 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 central torsionally elongated body.

[0033] To prevent the free ends of the shanks of these screws from bearing directly against the concrete and risking damage to it, the two lateral faces of said elongated central torsion body preferably have, at each interface zone, a corresponding metal contact plate sealed in the concrete and against which rest the free end(s) of said screw(s) emerging through the thread(s) provided on said lower end portion of a corresponding lateral branch.

[0034] According to advantageous construction characteristics, said parabolic cylindro-reflector is advantageously made up of several thin reflective slabs with a parabolic cross-section.

[0035] 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 the assembly of these monobloc elements two by two.

[0036] 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 by their longitudinal edges.

[0037] In order to allow adjustment of the orientation of the reflector with respect to the sun, said support structure is advantageously mounted to pivot around a longitudinal axis parallel to said linear focus of said parabolic cylindro-reflector by means of two supporting pillars arranged near the two longitudinal ends of this support structure.

[0038] Finally, and in order to ensure the anchoring of the solar collector to the ground without having to resort to buried foundations contributing to the artificialization and impermeability of the soils, said supporting pillars are each advantageously provided at their lower end with at least one concrete anchoring footing intended to rest on the ground.

[0039] 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. Brief description of the drawings

[0040] 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 accompanying drawings, on which: - [Fig.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; - [Fig.2] is a perspective view of a parabolic cylindrical solar collector according to the invention; - [Fig.3] represents an enlarged perspective view of one of the two pivoting articulation zones of the support structure of the parabolic-cylindrical solar collector of [Fig.2]; - [Fig.4] is a perspective view of one of the monoblock concrete elements that make up the trough of the support structure of the cylindrical-parabolic solar collector of [Fig.2]; - [Fig.5] represents an exploded perspective view of the support structure of the parabolic-cylindrical solar collector of [Fig.2]; - [Fig.6] is an enlargement of detail VI of [Fig.5]; - [Fig.7] represents a perspective view of one of the connecting elements that fixedly links two symmetrical monoblock elements opposite the trough of the support structure of the parabolic-cylindrical solar collector of [Fig.2]; and - [Fig. 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 torsional body of the parabolic-cylindrical solar collector of [Fig. 2]. Description of embodiments

[0041] Fig. 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.

[0042] 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.

[0043] The number of alignments and / or the number of parabolic-cylindrical solar collectors 1 of each alignment of such a solar collection set E can obviously vary according to the desired solar energy production capacity.

[0044] Fig. 2 represents one of the parabolic-cylindrical solar collectors 1 of this assembly E.

[0045] An orthogonal frame XYZ is defined with respect to this solar collector 1, comprising three axes perpendicular in pairs, namely: - an X axis, defining a longitudinal, horizontal direction, parallel to the linear focus of this solar collector 1; - 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 - a Z axis, defining a vertical direction perpendicular to the XY plane.

[0046] In the remainder of the description and with reference to the frame defined above, the terms "longitudinal" or "longitudinally" shall refer to a direction parallel to the X axis, the terms "transverse" or "transversely" shall refer to a direction parallel to the Y axis, and the terms "vertical" or "vertically" shall refer to a direction parallel to the Z axis.

[0047] On the other hand, 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.

[0048] 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.

[0049] Finally, the term "substantially" will indicate that a slight deviation is permitted from a predetermined nominal orientation, 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.

[0050] With reference to this [Fig.2], the parabolic-cylindrical solar collector 1 comprises 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.

[0051] 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 consisting of oil or water, circulates and is designed to absorb the heat generated by the light rays striking this tube.

[0052] 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 concrete, being pivotally mounted about a longitudinal axis A parallel to the focal point linear of the parabolic cylindro-reflector 100 by means of two supporting pillars 400 arranged near its two longitudinal ends.

[0053] It will be noted that such an essentially concrete construction 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).

[0054] The two supporting pillars 400 each comprise, in this case, two metal uprights 410 extending diagonally towards each other from their lower ends and joining at their upper ends, so as to form a V with its point directed upwards. Each supporting 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.

[0055] As can be seen more clearly in [Fig.3], each supporting pillar 400 further includes a metal support plate 430 surmounting the upper ends of the two uprights 410 and extending substantially horizontally.

[0056] According to alternative embodiments not shown, the supporting pillars 400 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 in concrete).

[0057] 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 concrete anchoring footing 440 intended to rest on the ground S. In this case, each supporting pillar 400 comprises two said concrete anchoring footings 440 each sealed to the lower end of a corresponding post 410.

[0058] 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 above-ground concrete footings 440 is made possible thanks to the intrinsic stability of the support structure 300 conferred naturally by its essentially concrete composition.

[0059] 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.

[0060] Still with reference to [Fig.2], the support structure 300 of the solar collector 1 comprises an elongated central torsional body made of concrete 310 oriented longitudinally and therefore parallel to the linear focus of the cylindrical-parabolic reflector 100.

[0061] As illustrated by [Fig.3], the pivoting articulation of the support structure 300 vis-à-vis the two supporting pillars 400 is advantageously ensured by means of two cylindrical metal pins 311 projecting at 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 supporting pillar 400.

[0062] 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.

[0063] As can be seen in this [Fig.3], the position of each rotating 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 supporting pillar 400.

[0064] This adjustment device 460 comprises in this case two threaded rods 461 spaced transversely apart from each other and passing through holes provided in the support plate 430 and on each of which are screwed two locking nuts 462, 463 sandwiching this support plate 430. The position of the rotating joint 450 can thus be adjusted by varying the position of the locking nuts 462, 463 along the threaded rods 461.

[0065] One of these two cylindrical pins 311 may advantageously be coupled to a motorized device so as to allow the rotation of the support structure 300 carrying the parabolic cylindro-reflector 100 to be controlled. 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.

[0066] Again with reference to [Fig.2], the support structure 300 also includes a trough 330 having a concave cylindro-parabolic upper surface supporting the reflector 100.

[0067] The trough 330 consists of several sections T joined longitudinally to each other and each comprising a pair of two identical monobloc concrete elements M extending symmetrically opposite each other on either side of the elongated central torsion body 310.

[0068] In the embodiment illustrated in the figures, the trough 330 consists of four identical sections T 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.

[0069] In order for these monobloc elements M to exhibit excellent tensile and flexural strength, they will advantageously be made of reinforced concrete or high-performance prestressed, advantageously equipped with stainless steel or galvanized steel reinforcement to protect it from corrosion.

[0070] To avoid any risk of corrosion, it is also possible to make these monobloc elements M in fiber-reinforced concrete although this may negatively impact their cost price as well as their flexural strength.

[0071] As illustrated by [Fig.4] representing 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).

[0072] 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 lower face 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 end and their outer end.

[0073] It will also be noted that the monobloc elements M advantageously have 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).

[0074] 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 ei preferably less than 2 meters and advantageously between 1.60 and 1.90 meters.

[0075] For the same reasons, the front and rear lateral support arms 332 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.

[0076] 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.

[0077] As illustrated by the exploded view in [Fig. 5], each section T also comprises 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 central torsion body 310 as shown by [Fig.2].

[0078] With reference to the enlargement of [Fig.6] and [Fig.7], each connecting member O comprises a top plate 334 and two substantially parallel lateral branches 335 each fixed by screwing against the inner end edge of a respective lateral support arm 332 of a corresponding monobloc element M.

[0079] More specifically, and as can be clearly seen in this [Fig.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 Vi (advantageously of type M24) spaced vertically apart, each passing through a respective orifice 335A (see [Fig.7]) provided in this lateral branch 335 and screwing into the internal thread of a corresponding anchor sleeve Di sealed in the concrete forming this lateral support arm 332 (these sleeves Di being represented in dashed lines in [Fig.8]).

[0080] In order to optimize the stability of the connection between the two monobloc elements M of the same section T, all the support arms 332 of the two monobloc elements M constituting this section T are advantageously connected two by two by such a respective connecting element O.

[0081] In order to facilitate the lifting and movement of the monobloc elements M to the assembly station of the sections T, these monobloc elements M may advantageously include other anchoring sockets D2, represented in dashed lines on the [Fig.4], sealed in the concrete (in particular near the inner and outer end edges of at least one of their lateral support arms 332) and on which anchoring devices (for example of the angle or ring type) not shown can be fixedly attached by screwing.

[0082] Still with reference to this [Fig.6], the top 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 [Fig.7]) provided in the center of this plate 334 and screwing into the internal thread of a corresponding anchor sleeve D3 sealed in the concrete forming this elongated central torsional body 310.

[0083] In order to facilitate the lifting and movement of the T sections to the assembly station for these sections 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 present two such threads arranged symmetrically on either side of its orifice 334A.

[0084] As can be seen in [Fig.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.

[0085] 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 Ml6) passing through a respective orifice 336A provided in this lower end portion 336 and screwing into the internal thread of a corresponding anchor sleeve D4 sealed in the concrete forming this torsionally elongated central body 310.

[0086] 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.

[0087] In the months following the commissioning of the collector 1, the phenomenon of concrete settling (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.

[0088] With reference to [Fig.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 [Fig.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.

[0089] As illustrated in this [Fig.8], these adjustment means preferably comprise, at each of said interface zones, two V4 screws screwed into two threaded holes respective 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.

[0090] In order to prevent the free ends of the shanks of the screws V4 from bearing directly against the concrete 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 concrete and against which rest the free end(s) of the screw(s) V4 opening through the threaded holes 336B provided on the lower end portion 336 of a corresponding lateral branch 335.

[0091] It will be noted in support of [Fig.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.

[0092] 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.

[0093] In view of the size of the monobloc elements M, it will be easily understood that a simple increase of a few millimeters in the depth of the portions of the screws V4 protruding through the threads 336B will be enough to cause a variation in the height of the deflection of the corresponding monobloc element M over several centimeters.

[0094] 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.

[0095] In order to ensure sufficient rigidity to prevent bending during the installation of the T sections onto the elongated central torsional 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 (by (example in steel) welded together and having a thickness of at least 10 millimeters and preferably between 15 and 25 millimeters.

[0096] 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 advantageously be configured so that the center of gravity of this rotating sub-assembly 100, 300 is located at the pivot axis A.

[0097] 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 concrete beam with an inverted T-shaped cross-section, the head 310A of which is oriented opposite to the trough 330 forms a counterweight allowing the center of gravity of the rotating sub-assembly 100, 300 to be brought to the level of this pivot axis A.

[0098] According to alternative embodiments not shown, 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.

[0099] As illustrated by [Fig.5], the parabolic cylindrical reflector 100 consists of a matrix array of nxm 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.

[0100] The adjective "thin" associated with the reflective slabs 110 must be interpreted in this case to mean that their thickness is sufficiently small in relation to their length and width so that the latter have a certain flexibility allowing them to perfectly conform, when cold and simply due to gravity, to the concave cylindro-parabolic upper surface of the trough 330 of the support structure 300.

[0101] Each reflective slab 110 advantageously comprises a transparent substrate, preferably made of glass because of its excellent light transmission combined with a controlled cost price, and covered on its convex underside with a reflective layer, for example of silver.

[0102] These reflective slabs 110 may also include at least one protective layer, in particular a copper or tin layer applied against the reflective layer.

[0103] 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 bonding (for example, using epoxy or polyurethane glue or even double-sided adhesives) before the formation of the T sections by assembling these monobloc elements M two by two via the connecting elements O.

[0104] 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.

[0105] In this case, and as illustrated by Figures 2 and 5, the upper surface of each supporting arch 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.

[0106] 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.

[0107] 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.

[0108] 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 embodiments within the reach of a person skilled in the art.

Claims

Demands

1. A parabolic-cylindrical 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 on said linear focus; and - a support structure (300) supporting said reflector (100) and comprising a longitudinally oriented elongated torsional central body of concrete (310) and a trough (330) having a concave parabolic-cylindrical 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 concrete elements (M) extending symmetrically opposite each other on either side of said elongated torsional central body (310).

2. Solar collector according to claim 1, characterized in that each said monobloc element (M) comprises a support arch having a concave upper surface with a half-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 said support arch (331).

3. Solar collector according to claim 2, 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 torsionally elongated central body (310).

4. Solar collector according to claim 3, 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).

5. Solar collector according to any one of claims 3 or 4, 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).

6. Solar collector according to claim 5, characterized in that the attachment of each said lateral branch (335) of a said connecting member (0) to a said respective lateral support arm (332) is achieved by means of at least two vertically spaced screws (Vi), each passing through a respective orifice (335A) provided in this lateral branch (335) and screwing into the internal thread of a corresponding anchor sleeve (Di) sealed in the concrete forming this lateral support arm (332).

7. Solar collector according to any one of claims 5 or 6, characterized in that the top plate (334) of each said connecting member (0) is screwed onto the top of said torsionally elongated central body (310) by means of at least one screw (V2) passing through a respective orifice (334A) provided in this plate (334) and screwing into the internal thread of a corresponding anchor sleeve (D3) sealed in the concrete forming said torsionally elongated central body (310).

8. Solar collector according to any one of claims 5 to 7, characterized in that each of said lateral branches (335) of said connecting member (0) has a lower end portion (336) projecting below said lateral support arm (332) on which it is fixed.

9. Solar collector according to claim 8, characterized in that said lower end portions (336) of said lateral branches (335) of each said connecting member (0) 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 anchor sleeve (D4) sealed in the concrete forming this torsionally elongated central body (310).

10. Solar collector according to claim 9, characterized in that it comprises adjustment means for finely readjusting the inclination of each of said monobloc elements (M) with respect to said torsionally elongated central body (310), said adjustment means comprising, at each interface zone between said lower end portion (336) of said lateral branch (335) of said connecting member (0) and a lateral side of said body elongated central torsional 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 elongated central torsional body (310).

11. Solar collector according to claim 10, characterized in that the two lateral faces of said torsionally elongated central body (310) have, at each interface zone, a corresponding metal contact plate (314) sealed in the concrete 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).

12. Solar collector according to any one of claims 1 to 11, characterized in that said parabolic cylindrical reflector (100) is made up of several thin reflective slabs (110) with a parabolic cross-section.

13. Solar collector according to claim 12, 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.

14. Solar collector according to claim 13, 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.

15. Solar collector according to any one of claims 1 to 14, 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.

16. Solar collector according to claim 15, characterized in that said supporting pillars (400) are each provided at their end 19 lower than at least one concrete anchor footing intended to rest on the ground.

17. Solar collection assembly consisting of at least one alignment of several parabolic-cylindrical solar collectors according to any one of claims 1 to 16.

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