FR3058782A1 - CARRIER STRUCTURE FOR A SOLAR POWER PLANT CARRYING A SYSTEM FOR CLEANING AND / OR MAINTENANCE OF SOLAR STRUCTURES - Google Patents

Abstract

The main object of the invention is a carrier structure (1) for solar power station (10) comprising a plurality of solar structures (11), characterized in that it comprises: a frame (6) comprising a central support beam ( 2) and two lateral structures (3), at each of the two ends (2a, 2b) of the support beam (2) and configured to come on either side of the solar structures (11) so that the chassis (6) spans them; displacement means (4) of the support beam (2) relative to the solar structures (11), formed at each of the two lateral structures (3) and configured to be located on either side of the solar structures (11). ); at least one support device (5), carried by the support beam (2), of at least one cleaning system (7) of fouled surfaces (M) and / or of a solar structure maintenance system (11). ).

Description

Holder (s): COMMISSION OF ATOMIC ENERGY AND ALTERNATIVE ENERGIES Public establishment, ASTF ENERGIE Limited liability company.

Extension request (s)

Agent (s): BREVALEX Limited liability company.

CARRIER STRUCTURE FOR SOLAR POWER PLANT CARRYING A SYSTEM FOR CLEANING AND / OR MAINTENANCE OF SOLAR STRUCTURES.

FR 3 058 782 - A1 (57) The main object of the invention is a support structure (1) for a solar power station (10) comprising a plurality of solar structures (11), characterized in that it comprises: a frame (6) comprising a raised central support beam (2) and two lateral structures (3), at each of the two ends (2a, 2b) of the support beam (2) and configured to come on either side of the solar structures (11) so that the chassis (6) spans them; displacement means (4) of the support beam (2) relative to the solar structures (11), formed at each of the two lateral structures (3) and configured to be located on either side of the solar structures (11 ); at least one support device (5), carried by the support beam (2), at least one cleaning system (7) for fouled surfaces (M) and / or a maintenance system for solar structures (11 ).

CARRIER STRUCTURE FOR SOLAR POWER PLANT CARRYING A SYSTEM FOR CLEANING AND / OR MAINTENANCE OF SOLAR STRUCTURES

DESCRIPTION

TECHNICAL AREA

The present invention relates to the general field of systems for cleaning dirty surfaces of solar structures of solar power plants and / or maintenance of solar structures of solar power plants. The invention is more specifically concerned with the field of photovoltaic solar power plants for which the solar structures are photovoltaic solar modules, and for which the fouled surfaces are typically glass surfaces, and also by the field of thermodynamic solar power plants for which the solar structures are solar reflectors, in particular reflectors with linear Fresnel mirrors (or “CLFR” for “Compact Linear Fresnel Reflector”), and for which the fouled surfaces are typically mirror surfaces.

The invention thus finds applications in various fields, for example for the cleaning of dirty surfaces of mirrors or panes of solar fields, the maintenance of solar modules or solar reflectors including in particular the installation and / or the replacement of solar modules or solar reflectors, or the maintenance of solar power plant receiver elements. In a privileged manner, the invention applies to the field of concentrated thermal solar (or even the field of “CSP” for “Concentrated Solar Power”), and more particularly to the field of linear Fresnel collectors.

The invention thus provides a support structure for a solar power station comprising a plurality of solar structures comprising a raised central support beam carrying at least one system for cleaning and / or maintenance of solar structures, a solar power station comprising such a support structure, as well as 'an associated cleaning and / or maintenance process.

PRIOR STATE OF THE ART

Among the technologies known in the thermodynamic solar sector, there is the concentrated solar thermal (CSP) technology which uses mirrors to concentrate the solar radiation on a small surface. The CSP technology consists more precisely in using solar radiation to heat a heat transfer fluid serving as a hot source in a thermodynamic cycle. The concentration makes it possible to reach more or less high temperatures, and thus to benefit from more or less significant thermodynamic conversion yields. The techniques developed around CSP technology are distinguished by their method of concentrating the sun's rays, their method of transport, and possibly storage, of heat, in particular by means of one or more heat transfer fluids, and their method of conversion. thermodynamics, for example through steam turbines, gas turbines, Stirling type engines, among others.

There are thus typically four families of concentrated solar systems belonging to the CSP technology, namely: cylindroparabolic collectors with linear focus, linear Fresnel collectors, central power plants with central receiver, and parabolic collectors with mobile focus.

The cylindro-parabolic collectors and the linear Fresnel collectors constitute solar systems with linear concentration, while the tower power stations and the parabolic collectors constitute solar systems with point concentration. In addition, Fresnel tower power plants and linear collectors constitute concentrated solar systems with fixed receivers, while parabolic collectors and cylindro-parabolic collectors constitute concentrated solar systems with mobile receivers.

A key element of such concentrated solar systems is the field of primary reflectors. For example, in the case of linear Fresnel collectors (CLFR technology), the field of primary reflectors, following the course of the sun from east to west during the course of a day, receives the direct light rays and reflects them in the direction of the fixed receiver. The concentration factor for such linear Fresnel collectors is typically of the order of 50, which means that the solar flux at the receiver is equal to approximately 50 times the solar flux which impacts the ground.

The functions of linear Fresnel mirror reflectors are to reflect, focus and direct the incident solar flux. The reflection of the mirrors must therefore be specular. By "specular reflection" is meant the amount of light reflected in a precise direction of incidence. In particular, the ray of light reflected in a specular manner is the ray which is at the symmetry of the incident ray with respect to the normal of the reflecting surface. Furthermore, the expression “diffuse reflection” designates the whole quantity of reflected light other than that reflected in a specular manner. Thus, the total reflection of a mirror corresponds to the sum of the specular reflection and the diffuse reflection.

However, when these Fresnel mirrors are dirty, their total reflection drops slightly but above all their specular reflection decreases considerably, thus impacting the primary functionality of such mirrors. Indeed, a large diffuse reflection certainly provides a high reflectivity, but it does not ensure the function of orientation and concentration towards the precise target that is that of the receiver.

These functionalities and associated cleaning needs, described above for Fresnel linear collectors, are found for the four families of CSP technology. Indeed, for all this technology, the reflectors have the function of reflecting and concentrating all of the incident direct solar irradiation towards the receiver, located a few meters or a few tens of meters from the reflectors. They are made up of mirrors assembled to a structure mounted on rotation systems enabling the sun's course to be followed during the day. All families of CSP technology therefore use similar mirrors, subject to the same environmental conditions and the same durability requirements.

Also, all technologies from CSP technology require cleaning of the mirrors for their proper functioning. In particular, of the three families of existing materials for the design of mirrors, namely polymer, aluminum and glass, glass mirrors represent more than 80% of the mirrors installed on thermodynamic solar power plants. It is thus for this type of mirrors that the cleaning issues are most critical for manufacturers who have implemented, or plan to install, a concentrated solar thermal power plant.

In the case of the CLFR technology of Fresnel linear collectors, the specificities thereof must be taken into account when developing solutions for cleaning the mirrors. In particular, the lines of reflectors have a considerable length, for example of the order of 100 to 300 m, or even up to 900 m. In addition, approximately between 10 and 20 lines of reflectors are connected in parallel, illuminating the same receiver. Fresnel mirrors are also not very curved (the radii of curvature are between approximately 15 and 30 m), unlike for example the mirrors of cylindro-parabolic collectors. In addition, Fresnel mirrors of the same line form a non-continuous surface, because there is a space between reflectors every 6 to 10 m because the reflectors are supported by metallic structures fixed to the ground on which they are placed. in rotation.

Solutions for cleaning mirrors of solar power plants, and in particular mirrors of solar power plants comprising reflectors with linear Fresnel mirrors, have already been envisaged in the prior art.

In general, these solutions must be able to respond to the problems posed by cleaning the mirrors. In particular, mirrors get dirty, this reduces their reflectivity and therefore the thermal and electrical power generated by a solar power plant. Soiling can come from many sources, such as aerosol particles, inorganic matter from soil erosion (agricultural land nearby), organic matter (such as pollen, bacteria, algae, lichen, droppings ), or sand and / or dust from a desert environment.

A review of the possible sources of fouling, their effect and the possibilities of cleaning has also been carried out in the book entitled "A comprehensive review of the impact of dust on the use of solar energy: History, investigations, results, literature, and mitigation approaches ”, T. Sarver et al, Renewable and Sustainable Energy Reviews, Volume 22, June 2013, pages 698-733.

In CSP technology, the loss of reflectivity is particularly sensitive to dust deposits on the surface since only specular reflectivity is exploited. The presence of dust on a mirror tends to diffuse the reflected light, the problem of fouling has much stronger consequences than in the case of a photovoltaic system on productivity, namely the thermal power generated, a CSP plant since it directly impacts the exploitable solar resource.

As previously mentioned, glass mirrors are the most used in concentrated solar power plant installations. Such mirrors consist of a glass substrate, with a thickness of about 2 to 5 mm, on which is deposited a thin layer of reflective silver protected by a metal layer on the rear face. A system of several layers of paint is applied to the rear face of the mirror to protect the metal layers against corrosion. Cleaning a mirror therefore generally means cleaning glass, or even a hard layer deposited on the surface for aluminum and polymer mirrors.

Concentrating solar power plants (CSP) are generally installed in areas of the world where the sun is strong, but more often arid and dry areas where the clogging of the mirrors can be fast. In these areas, there is little “natural” cleaning of the mirrors by rain, although there may be dew in the morning on the mirrors. Thus, regular cleaning of the mirrors is required to maintain the performance of the solar field, at lower cost and lower consumption of water which is a scarce resource in areas suitable for CSP technology. It should be noted that the losses in reflectivity can range from less than 1% per week to more than 10% depending in particular on the location, the presence of wind or a sandstorm for example.

The cleaning method most used since the 1980s, on solar fields, consists of spraying, under pressure or not, distilled water on the mirrors and brushing them. However, it is not entirely satisfactory, in particular because of the need for a large amount of water which it implies and because of the risk of abrasion over time in contact with the brushes. In addition, preventive techniques have also been studied to consider surface treatments to make the mirrors hydrophobic or self-cleaning. However, these techniques presuppose the development of surface treatments which do not alter the reflectivity of the mirrors and which resist weather conditions over time, such as strong temperature variations, abrasion or ultra-violet radiation.

Furthermore, other technologies for cleaning mirrors of solar power plants have been described in the prior art. They are presented below.

Thus, patent application US 2012/0152281 A1, international application WO 2010/106195 A1 and international application WO 2011/106665 A2 describe for example cleaning techniques used on solar fields of the cylindroparabolic type, using a vehicle , truck or tractor type, which carries a cleaning arm and transports a large amount of water. With such systems, the cleaning arm cleans the mirror by spraying water, coupled or not with mechanical brushing. However, these systems have only been developed for parabolic power plants. They also consume a lot of water, as it is generally not recovered and / or recycled. In addition, when brushes are used in addition to spraying with distilled water, cleaning is improved but the risk of breakage is significant. The vehicles used are also very heavy because they must carry a lot of water, which requires a preparation of the soil adapted to the repeated rolling of heavy vehicles. However, this soil preparation can be difficult, if not impossible, for example in the desert. In addition, it is also very expensive. Regular cleaning with such vehicles results in the appearance of ruts on the floor. In addition, when moving, vehicles raise dust which can redeposit on the mirrors and foul them again. In addition, these solutions require the presence of an operator.

There is also known the “PARIS” cleaning system (PARabolic trough cleaning System), developed by the company SENER Aerospace, which provides for the use of an autonomous machine, driverless, and lighter than the vehicles described above. Cleaning is also carried out by brushing with water spray, and water consumption is high.

The systems described above, using vehicles with offset arms for cleaning, are not suitable for the solar field of Fresnel type mirrors, precisely because of the use of offset arms.

Indeed, a solar field of Fresnel mirrors comprises several lines of parallel mirrors which are placed under the receiver, the total width of these lines exceeding 10 m and being able to go up to 20 m. A vehicle, for example a truck, traveling on the edge of the solar field would therefore have to unfold a cleaning arm of a very long length in order to be able to clean the mirrors, which seems difficult to achieve. In addition, the receiver is supported in height by feet, or beams, with in most cases reinforcement cables anchored to the ground, which hinders access from the sides of the solar field on the periphery thereof and hinders also access between two lines of mirrors.

Other technologies have appeared in the prior art for the specific cleaning of Fresnel type solar fields. Thus, international application WO 2011/113555 A2, in connection with the “HECTOR” system (HEliostats Cleaning Team Oriented Robot) developed by the company SENER Aerospace, describes an autonomous energy robot intended to roll on a mirror to clean it, guided by an optical system and carrying only the quantity of water necessary for cleaning a line of mirrors. Cleaning is done by brushing and spraying water. This system is expensive and complex, because it requires the management of a fleet of small robots with a transport system, each robot having to be filled with water and recharged with energy at the end of lines of Fresnel reflectors. In addition, guidance by optical system involves reliable control, maintenance of the optical system and involves risks of failure, for example in the event of the robot falling.

US Patent 8,240,320 B2 also describes a robot guided on the structure of the reflector, cleaning the mirrors by brushing with water. This system has several faults, among which: the guidance on the edge of the mirrors and of the structure which supports them, causing a risk of breakage of fragile mirrors; the drive by wheels in contact with the mirrors with the risk of redeposition of dirt under the wheels and scratching of the mirrors; the addition of weight on the mirrors preventing the lightening of the support structure and therefore a reduction in costs; the need for a robot recovery system at the end of the line to make it change the line and then change the unit solar field, automation being complex with the risk of breaking the mirrors; regular and unitary recharging of the robot because, being carried by the mirrors, it cannot take a lot of water or energy.

In addition, utility model CN 202 336 465 U describes the use of air blast cleaning, self-supporting on the mirror. Cleaning by blowing air is however very energy consuming, for compressing the air, and ineffective for dust stuck to the mirror.

STATEMENT OF THE INVENTION

There is therefore a need to propose an alternative solution to allow the cleaning and / or maintenance of solar structures, for example solar modules or reflectors, solar power plants, and in particular solar power plants comprising reflectors with linear Fresnel mirrors. . More specifically, there is a need to design a system for cleaning and / or maintenance of such solar structures which makes it possible to act over the entire width of a solar field without placing the weight of the system on the solar structures, in particular during of its movement, and without mechanical guidance on the surfaces of solar structures. Such a system must also be provided to be simple and inexpensive, autonomous in water and energy, and without risk of breakage of the windows or mirrors (absence of mechanical contact between the cleaning means and the surface of the windows or mirrors). Likewise, the guidance of the system must not require a human pilot and the passage from one solar field to another must be possible.

The object of the invention is to at least partially remedy the needs mentioned above and the drawbacks relating to the embodiments of the prior art.

According to one of its aspects, the subject of the invention is therefore a support structure for a solar power station comprising a plurality of solar structures, for example solar modules or solar reflectors, in particular a plurality of parallel lines of solar modules or reflectors. , in particular of reflectors of the linear Fresnel mirror type, characterized in that it comprises:

- a frame comprising a raised central support beam and two lateral structures, respectively located at each of the two ends of the support beam and configured to come on either side of the plurality of solar structures so that the frame spans the plurality of solar structures,

means of displacement, in particular in translation, of the support beam relative to the plurality of solar structures, formed at least partly at each of the two lateral structures and configured to be at least partly in contact with the ground and located on either side of the plurality of solar structures,

- at least one support device, carried by the support beam, of at least one system for cleaning dirty surfaces of solar structures, in particular mirrors of solar reflectors or panes of solar modules, and / or of a system maintenance of solar structures.

Thanks to the invention, it may be possible to avoid any mechanical contact between the support structure and the surfaces of the solar structures so as to avoid any risk of breakage. In addition, the guiding in movement of the supporting structure can be carried out in a safe and reliable manner, in particular by means of a mechanical system. The supporting structure according to the invention can also be advantageously used for both cleaning and maintenance of solar structures. Furthermore, the use of means of movement at ground level can make it possible to better manage the interstructure space. The need for labor is also significantly reduced, as well as the overall operating costs of the supporting structure. The movement of the supporting structure being managed at the edge of the solar field, all maintenance is facilitated, in particular in the event of a breakdown of the motorization. Furthermore, the invention advantageously makes it possible to be able to pool cleaning and / or maintenance systems, or even receiver construction systems and systems for cleaning and / or maintenance of solar structures.

The supporting structure according to the invention may also include one or more of the following characteristics taken in isolation or according to any possible technical combination.

Advantageously, the load-bearing structure according to the invention is thus of the straddle type, namely that it makes it possible to span several lines of solar structures by taking in particular support on the ground on either side of these lines of solar structures . The term "straddle" is used here by analogy with its meaning in the field of agricultural tractors, in particular for the treatment of vines.

In addition, the two lateral structures advantageously extend parallel in a substantially vertical plane.

The elevation of the central support beam also allows it to be located above the plurality of solar structures.

Said at least one cleaning system can advantageously be retractable and / or removable.

Said at least one cleaning system can be carried by said at least one support device. However, said at least one cleaning system can also be placed on the surface to be cleaned after being carried by said at least one support device.

The supporting structure may comprise at least one system for cleaning dirty surfaces of solar structures, in particular dirty windows of solar modules or mirrors dirty with solar reflectors, and said at least one support device may include means for guiding the movement of said at least one cleaning system.

The supporting structure may also comprise at least one system for cleaning dirty surfaces of solar structures, in particular dirty windows of solar modules or mirrors dirty with solar reflectors, and said at least one support device may include means for spraying '' cleaning fluid, especially water, on dirty surfaces.

The means for moving the support beam may include guide wheels secured to each lateral structure. The guide wheels can be carried by the axles fixed on each lateral structure.

The displacement means can also comprise at least one guide rail associated with each lateral structure, on either side of the plurality of solar structures, each guide rail cooperating with the guide wheels fixed on the lateral structure associated with said rail. guide to allow movement of the support beam relative to the plurality of solar structures.

Each lateral structure can also, as a variant, comprise orientable guide wheels, in particular four guide wheels, configured to be in direct contact with the ground.

In the case where it has orientable guide wheels, the support structure may also comprise at least one positioning element, in particular two positioning elements respectively at each end of the support beam, configured to cooperate with at least one positioning rail fixed to a post of the solar power station receiver located on one side of the plurality of solar structures, in particular with two positioning rails respectively fixed to a first post of the solar power station receiver located on one side of the plurality of structures solar panels and a second pole of the receiver of the solar power plant located on the other side of the plurality of solar structures, to allow the displacement of the support beam relative to the plurality of solar structures.

Furthermore, each lateral structure may include a motorization system allowing the movement of the guide wheels.

In addition, said at least one support device can be carried by the support beam by means of lifting means fixed to the support beam, for example a lifting winch or even a chain hoist.

The supporting structure may also include a maintenance system for the receiver of the solar power plant, in particular a maintenance system deployable vertically above the support beam and extending from the support beam.

The chassis of the support structure, in particular the support beam, may have a modular dimensioning to adapt to the number of solar structures, in particular a modular width as a function of the number of lines of solar structures.

The supporting structure may further comprise means for supplying cleaning liquid, in particular a tank for cleaning liquid and / or a circuit for supplying cleaning liquid connected to one or more cleaning systems, supported by the chassis. the supporting structure. In particular, at least one lateral structure, in particular each lateral structure, may comprise a reservoir of cleaning liquid, in particular water.

In addition, said at least one cleaning system may comprise means for spraying a cleaning liquid, in particular water, onto the dirty surfaces, in particular the dirty windows or the dirty mirrors. In particular, each cleaning system may include such means for spraying a cleaning liquid.

Said at least one cleaning system may further comprise means for supplying cleaning liquid, in particular a tank for cleaning liquid. In particular, each cleaning system may include such means for supplying cleaning liquid, in particular a tank for cleaning liquid.

One or more solar structures, for example each solar structure, may also include means for supplying cleaning liquid, in particular a tank for cleaning liquid.

In addition, the invention also relates, according to another of its aspects, to a solar power plant, characterized in that it comprises a plurality of solar structures, in particular solar modules or solar reflectors, and a supporting structure such as defined above, the support structure being able to allow cleaning and / or maintenance of the plurality of solar structures.

The support structure may in particular comprise steerable guide wheels as described above, and the solar power plant may include a receiver comprising a post on which is fixed at least one position sensor capable of detecting the presence of the support structure to allow its guidance during its displacement relative to the solar structures.

The solar power plant may in particular correspond to a linear Fresnel collector, comprising a plurality of parallel lines of reflectors of the linear Fresnel mirror type.

Furthermore, the subject of the invention is also, according to another of its aspects, a method of cleaning and / or maintenance of a plurality of solar structures, in particular solar modules or solar reflectors, of a solar power station, characterized in that it is implemented by means of a support structure as defined above, and in that it comprises the step of displacement of the support structure relative to the plurality of solar structures by means displacement means at least partly in contact with the ground.

The displacement means can for example comprise a traction system with motor, the motor being in particular not positioned on the supporting structure but, for example, at the end of the solar field and being able to carry out a traction by cable.

The supporting structure, the solar power plant and the cleaning and / or maintenance method according to the invention may include any of the characteristics stated in the description, taken in isolation or in any technically possible combination with other characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood on reading the detailed description which follows, of non-limiting examples of implementation thereof, as well as on examining the figures, schematic and partial, of the appended drawing, on which :

FIG. 1 represents, in perspective and partially, an example of a solar power plant provided with a plurality of parallel lines of reflectors of the linear Fresnel mirror type, comprising a support structure in accordance with the invention,

FIG. 1A is a detail view along A of FIG. 1,

FIG. 2A partially shows a side view along C of FIG. IA,

FIG. 2B partially shows in perspective the view of FIG. 2A,

FIG. 2C illustrates, partially and in a side view similar to that of FIG. 2A, another example of a supporting structure according to the invention,

FIG. 3 illustrates, partially and in perspective, an example of a support structure according to the invention comprising a maintenance system for solar reflectors,

FIG. 4 is another perspective view of the support structure of FIG. 3 illustrating the possibility of maintenance of the receiver of the solar power station,

FIG. 5 very schematically illustrates the possibility for a support structure according to the invention to have a modular appearance,

FIGS. 6A and 6B illustrate very schematically, in top view, the possibility for a support structure according to the invention to include steerable guide wheels,

FIG. 7 represents, partially in front view, the positioning of a support structure according to the invention relative to a support post for a solar power plant receiver,

FIGS. 8 and 9 very schematically illustrate two configurations for using load-bearing structures according to the invention as a function of the mounting of the receiver of a solar power station,

FIGS. 10 and 11 show, partially in front view, two examples of solution for guiding a support structure in accordance with the invention in the case where it comprises orientable guide wheels,

FIG. 12 represents, partially in front view, a support structure according to the invention comprising a reservoir of cleaning liquid,

FIGS. 13A to 13C illustrate, partially in side view, three steps of a method for cleaning mirrors of solar reflectors by means of a support structure according to the invention,

FIG. 14 represents, partially in a perspective view, another example of a supporting structure according to the invention, and

- Figure 15 is a front view of the support structure of Figure 14, here comprising a maintenance system of solar reflectors, and aims to illustrate the possibility of maintenance of the receiver of the solar power plant, as illustrated above for the example in Figure 4.

Throughout these figures, identical references may designate identical or analogous elements.

In addition, the different parts shown in the figures are not necessarily shown on a uniform scale, to make the figures more readable.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

In the description of examples of implementation of the invention which follows, the field of application concerned is that of thermodynamic solar power plants for which the solar structures are solar reflectors, and in particular here reflectors with linear Fresnel mirrors and for which also the dirty surfaces are mirror surfaces.

However, as indicated above, the invention is not limited to this field of application and could in particular relate to the field of photovoltaic solar power plants for which the solar structures are photovoltaic solar modules, and for which the fouled surfaces are window surfaces.

With reference to FIG. 1, and to FIG. 1A which is a view of details according to A of FIG. 1, an exemplary embodiment of a solar power station 10 of the Fresnel type is presented below, comprising sixteen parallel lines of reflectors 11 of the CLFR type, that is to say of the linear Fresnel mirror type, and comprising a support structure 1 according to the invention.

The supporting structure 1 thus firstly comprises a frame 6, which comprises a central support beam 2 raised above the solar reflectors 11, provided with mirrors M clogged in glass, and two lateral structures 3, here generally triangular in shape and extending parallel to each other in a substantially vertical plane, respectively located at each of the two ends 2a and 2b of the support beam 2.

Advantageously, the lateral structures 3 are configured to come on either side of the solar reflectors 11 so that the chassis 6 spans the solar reflectors 11, as visible in FIG. 1. Thus, the chassis 6 of the supporting structure 2 is not in contact with the solar reflectors 11, and in particular their dirty mirrors M.

Furthermore, the carrying structure 2 also comprises means 4 for moving the support beam 2 relative to the solar reflectors 11. These movement means 4 allow in particular the displacement in translation of the frame 6, and therefore of the support beam 2, according to the arrow F shown in FIG. 1, along the parallel lines of solar reflectors 11.

These displacement means 4 are at least partly formed at each of the two lateral structures 3 and are generally configured to be located on either side of the solar reflectors 11.

In addition, the supporting structure 2 comprises a plurality of support devices 5, carried by the latter, and allowing the support of a plurality of cleaning systems 7 for the mirrors M of the solar reflectors 11. Each cleaning system 7 is advantageously retractable and removable. Each cleaning system 7 comprises for example a cleaning brush or any other cleaning means, for example a cleaning robot as known in the prior art. It should be noted that each cleaning system 7 can be placed on the surface to be cleaned, after having been carried by means of a support device 5 when the supporting structure 1 was approaching the solar field.

Advantageously, the cleaning systems 7 make it possible to clean all of the mirrors M of all the lines of solar reflectors 11 in the same phase.

FIG. 1 also represents the receiver R of the solar power station 10, the relationship of which with the supporting structure 1 according to the invention will be described in more detail below.

FIGS. 2A and 2B show, respectively in a side view and a perspective view, the support structure 1 of FIGS. 1 and 1A in order to better visualize the elements attached to a support device 5.

First of all, as best seen in these FIGS. 2A and 2B, the displacement means 4 of the support beam 2 comprise guide wheels 4a which are secured to each lateral structure 3. More particularly, each lateral structure 3 has two axles 4c respectively carrying a guide wheel 4a so that each lateral structure 3 comprises a front guide wheel and a rear guide wheel.

In addition, the displacement means 4 comprise two guide rails 4b, namely a guide rail 4c on each side of the solar reflectors 11, in which the guide wheels 4a move. More precisely, the two front and rear guide wheels 4a carried by a lateral structure 3 move in translation in the guide rail 4b associated with this lateral structure 3.

Thus, the supporting structure 2 straddles the solar reflectors 10 on either side of them and manages to move along these to allow the cleaning of the mirrors M thanks to the movement of the guide wheels 4a in the guide rails 4b located on either side of the solar reflectors 11, in contact with the ground. The supporting structure 1 therefore moves by rolling on the ground in the space situated at the edge of the solar field.

Advantageously, each lateral structure 3 comprises a motorization system allowing in particular the movement of the guide wheels 4a in the guide rails 4b. This motorization system advantageously includes a heat engine, guaranteeing a large autonomy, greater than that of the batteries. The heat engine then drives the guide wheels 4a by mechanical coupling. It can also drive an oil pump with wheels which are then hydraulically driven. It can also run an alternator with electric wheels.

The supporting structure 1 can advantageously include the fuel necessary for supplying the motorization system, and in particular the heat engine. This heat engine can also drive a pump to pressurize the cleaning liquid, in particular water, which can then be sprayed in front of the cleaning systems 7, in particular of cleaning brushes.

The guide wheels 4a are advantageously metal wheels, in particular steel, to allow their movement along the guide rails 4b also metallic. In order to be able to pass from one solar field to another solar field, the displacement means 4 can also include wheels for driving on the ground, for example wheels with an inner tube or solid rubber, or any other type of wheel. existing, not shown, each metal guide wheel 4a being in particular associated with such a wheel.

In the configuration for using the support structure 1 on a solar field, in particular in the configuration for cleaning the mirrors M of solar reflectors 11, the metal guide wheels 4a are in contact with the guide rails 4b and allow precise guidance throughout of the operation. On the other hand, at the end of use, in particular at the end of cleaning, and in order to move to another solar field, the metal guide wheels 4a retract and leave room for the wheels allowing rolling on the unprepared ground of the solar field, in other words outside the guide rails 4b. The principle of this cooperation between metallic guide wheels 4a and wheels specific to running on the ground can be similar to that of construction machinery used for laying train or tram tracks.

In addition, as visible in FIGS. 2A and 2B, a given support device 5 can comprise two cleaning systems 7, for example of generally circular shape, intended to be raised or lowered near the mirrors M by means of guide 9, in particular in the form of guide arms 9, of the movement of the cleaning systems 7. These guide means 9 may for example comprise pneumatic cylinders making it possible to raise the cleaning systems 7 at the end of the line and the repositioning on the following lines.

Advantageously, in this example, the support device 5 is carried by the support beam 2 by means of a lifting winch 15 fixed to the support beam 2. This lifting winch 15 makes it possible to raise and lower the support device 5, and therefore the cleaning systems 7, with respect to the solar reflectors 11.

In addition, the support device 5 can also include other elements 16 participating or not in the cleaning process of the mirrors M, such as electromechanical equipment.

Furthermore, FIG. 2C illustrates the possibility of having means 12 for spraying a cleaning liquid, in particular water E, on the dirty mirrors M, these means being carried by the support device 5. These spraying means 12 are for example located upstream of the cleaning system 7, considering the direction of movement of the support beam 2, so that the mirrors M are covered with water before the cleaning system 7 passes. more, this figure 2C also illustrates the possibility of directly supporting the support device 5 by the support beam 2 without the intermediary of a lifting winch 15, as described above.

Furthermore, as will be described more fully below with reference to FIG. 12, it should be noted that at least one lateral structure 3, in particular each lateral structure 3, may comprise a reservoir of cleaning liquid 14, in particular a water tank, for cleaning the mirrors M of the solar reflectors 11.

The support device (s) 5, allowing the support of the cleaning systems 7, can also be used for the maintenance of the solar reflectors 11, notably comprising the mounting of the solar field or the maintenance of the solar field. Thus, these support devices 5 can support maintenance systems 8 taking the form of devices for carrying the reflectors 11 so as to bring or extract a solar reflector 11 in any location of the solar field. The solar reflector 11 is removed from its location and transported to the headland for maintenance.

Thus, FIG. 3 illustrates the possibility of using the support structure 1 according to the invention for the maintenance of the solar reflectors 11.

The support beam 2 comprises a plurality of lifting winches 15 fixed thereto and attached to support devices 5 of maintenance systems 8 to allow the lifting along arrow H of a line of solar reflectors 11, as shown. In this example, each support device 5 may in fact correspond to lifting cables, or slings, secured to other lifting cables (or slings) or to a lifting frame 8 surrounding the line of solar reflectors 11 on its width to allow maintenance.

Also, the invention turns out to be particularly suitable for the maintenance of solar reflectors 11. In fact, it is known that over the lifetime of a solar power station 10, certain mirrors M of the solar reflectors 11 can suffer damage, such as breakage or corrosion, which require replacement. Such a replacement is problematic for the mirrors M which are not on the lines of the edge of the solar field because access is difficult, and all the more so since the lines of solar reflectors 11 are usually tightened to optimize the grip on the ground. Advantageously, the supporting structure 1 according to the invention therefore allows the replacement of defective solar reflectors 11.

Furthermore, FIG. 4 illustrates the possibility for the supporting structure 1 according to the invention to allow maintenance intervention on the receiver R of the solar power station 10.

Thus, the support structure 1 comprises a maintenance system 17 for the receiver R which is capable of deploying vertically above the support beam 2 to reach the receiver R. In other words, the support beam 2 can serve as a platform or support for the deployment of the maintenance system 17 of the receiver R.

This maintenance system 17 can for example be a cleaning system 17 for the window V placed in the lower part of the receiver R. In fact, the receiver R is a cavity which contains the absorber, namely tubes through which the heat transfer fluid passes. , and a window V in the lower part in order to allow the concentrated flow to pass and to “close” the receiver R to limit losses by convection. This pane V is actually made up of glass plates, with a typical length of 1 m, placed end to end in a metal slide at the bottom of the receiver R.

This window V gets dirty in service, at a much slower speed than the mirrors M because it is located high up, where there is less dust raised by the activity around the solar field, and than the surface exposed to the air. ambient is directed to the ground.

However, under the effect of the expansion cycles corresponding to the operating days, there may be movements of the glass plates which lead to overlapping, breakage or the like, requiring maintenance and replacement. However, access to the glass V is not simple because conventional nacelles must be able to bring a person under the glass V from the edge of the solar field, or an offset of 8 to 10 m. In addition, when replacing with a nacelle, any falling tool is liable to break mirrors M whereas if the person is on the carrying structure 1 according to the invention, it can be located on a platform 18 of the maintenance system 17 comprising a floor, consisting for example of a metal sheet, making it possible to protect the mirrors M in the event of tools falling on the floor.

FIG. 5 illustrates the possibility for the supporting structure 1 according to the invention to be able to be modular to adapt to the number of lines of solar reflectors 11. In particular, the supporting structure 1 can have a modular width as a function of the width of the solar field on which it will be used.

The chassis 6 of the supporting structure 1 is typically made up of beams, in particular of metal, fixed to one another, in particular by welding. Advantageously, this assembly of beams can be carried out in a modular manner in order to be able to adapt the working width to different solar power stations 10 for which the width of the solar field would be changed.

Thus, the supporting structure 1, and in particular its chassis 6, can comprise end parts PI and P3 forming fixed zones in which the chassis 6 consists of beams fixed to each other, in particular mechanically welded, and a central part P2 forming a modular zone in which the chassis consists of beams fixed to one another, in particular mechanically welded, but capable of being fixed to the beams of the end parts PI and P3, in particular by means of bolts and flanges. In other words, there may be a plurality of central parts P2 having different widths and one of them is used between the end parts PI and P3 according to the total width desired for the support structure 1.

The displacement of the supporting structure 1 according to the invention with respect to the solar field can be done by means of the cooperation between guide wheels 4a and guide rails 4b as described above. As a variant, this movement can also be done by means of guide wheels 4a driven by motorization means and orientable, these guide wheels 4a coming directly into contact with the ground without having to use the guide rails 4b previously described.

FIG. 6A illustrates, according to a top view, this principle consisting in having, at each lateral structure 3, a platform here comprising four orientable guide wheels 4a, in particular wheels for rolling on the ground, for example wheels with inner tube or solid rubber, or any other type of existing wheel. This platform provided with these four guide wheels 4a can for example be related to a quad. The supporting structure 1 can thus move along the solar field CS, by means of four guide wheels 4a on each side of the solar field CS.

FIG. 6B illustrates the change of orientation of the guide wheels 4a in order to be able to pass from a solar field CS to another solar field CS.

We have also illustrated, with reference to FIG. 7, the fact that the supporting structure 1 moves by rolling on the ground, by means of guide wheels 4a with guide rails 4b or of guide wheels 4a which can be oriented, in the space located at the edge of the solar field under the posts 21 carrying the receiver R. As shown in this FIG. 7, the displacement means 4 are located between the edge of the last row of solar reflectors 11 and the feet of the posts 21 of receptor support R.

When the supporting structure 1 moves on the ground relative to the solar reflectors 10, it may be desirable to be able to manage the unevenness of the ground surface.

In the case where the displacement means 4 comprise guide reds 4a moving on guide rails 4b, it is the guide rails 4b themselves which make it possible to correct the roughness of the ground surface. The use of lateral guide rails 4b makes it possible to take advantage of the presence of studs, typically made of concrete, which are necessary for anchoring the supports of the solar reflectors 11 in the ground and on which the guide rails 4b can be placed.

In the case where the displacement means 4 comprise orientable guide wheels 4a and are therefore devoid of guide rails, a system for managing the height of the support beam 2, for example by means of a measurement sensor for distance from the mirrors M, may be necessary to correct the roughness of the ground surface. Minimal soil preparation is desirable for rolling, which is advantageously only slightly degraded by the movement of the supporting structure 1 due to its low weight. The use of inflatable wheels for the steerable guide wheels 4a, as according to the example of FIG. 14 described below, makes it possible to reduce the unevenness of the ground surface.

Figures 8 and 9 illustrate two types of support configuration of the receiver R of the solar power station 10 and thus the ways in which the invention is implemented according to these configurations.

FIG. 8 illustrates the case where the receiver R is supported by poles 21 situated outside the solar field, in other words without pole in line with the receiver R. In this case, the support structure 1 can span the solar field on the and other of it, as described above.

Figure 8 illustrates the case where the receiver R is supported by a single pole 21 located to the right of it, with reinforcing cables anchored outside the solar field. Then, the supporting structure 1 according to the invention is intended to be used only for a half solar field CS1 or CS2.

Furthermore, in the case where the support structure 1 comprises guide wheels 4a which can be oriented as described with reference to FIGS. 6A and 6B, it may nevertheless be necessary to provide a solution for guiding the support structure 1 relative to the solar reflectors 10.

Thus, FIG. 10 illustrates a first solution for guiding the support structure 1 relative to these solar reflectors 10 in the case of the presence of orientable guide wheels 4a.

As shown, each end 2a, 2b of the support beam 2 comprises a positioning element 20 which cooperates with a corresponding positioning rail 22 fixed on a post 21 corresponding to the receiver R of the solar power plant

10. The sliding of the positioning elements 20 in the positioning rails 22 then allows the support beam 2 to move relative to the solar reflectors 11.

FIG. 11 illustrates a second solution for guiding the support structure 1 relative to the solar reflectors 10 in the case of the presence of orientable guide wheels 4a.

Thus, as shown, each pole 21 of the receiver R may include a local position sensor 23 capable of detecting the presence of the support structure 1 to allow its guidance during its movement relative to the solar reflectors 11. Several position sensors 23 can be provided on several posts 21 of the receiver R thus forming guide relays for the support structure 1.

Furthermore, in the case of the second solution, rows of sensors, or buried proximity sensors, can be arranged between two solar fields so that the carrier structure 1 can follow them and can position itself on the next solar field. In the case of the first solution, rail outlets can be provided.

FIG. 12 also illustrates the possibility for the support structure 1 to comprise means for supplying cleaning liquid comprising a cleaning water tank 14 located on a lateral structure 3, and in particular a water tank 14 on each lateral structure 3. In addition, these means for supplying cleaning liquid also comprise a water supply circuit 24 connected to the water tanks 14 and capable of circulating the cleaning water up to each cleaning system. 7 to allow cleaning of the mirrors M.

Advantageously, the invention makes it possible to be able to pool the cleaning water tanks of all the cleaning systems 7. In other words, one or two cleaning water tanks 14 may suffice to supply all the cleaning systems 7, which reduces costs and simplifies filling operations.

This cleaning water advantageously corresponds to demineralized water necessary for cleaning a solar field, for example at a temperature less than or equal to 60 ° C., in particular between 40 and 60 ° C. Each cleaning tank 14 can for example have a capacity of 100 to 300 liters of cleaning liquid.

Advantageously, thanks to the support structure 1 according to the invention, the solar reflectors 11 can therefore only support the weight corresponding to the contact pressure of the cleaning brushes.

Furthermore, filling with cleaning liquid, in particular water, and / or energy from the solar power station 10 can generally be done at the end of the line, for example with local tanks which can be buried. There is then no need for trucks to transport the robots, the filling of these tanks being then carried out occasionally with the help of a dedicated truck. It is also possible to provide for the construction of the solar power station 10 with a network of pipes for cleaning liquid. In this case, the latter, in particular demineralized water, can be produced in a central unit on site, thereby reducing the overall operating costs of the solar power station 10.

In addition, FIGS. 13A to 13C respectively illustrate various stages of a sequence for cleaning mirrors M of solar reflectors 11 of the solar power station 10.

In the case of FIG. 13A, the cleaning systems 7 are approaching the mirrors M of the solar reflectors 11.

In the case of FIG. 13B, the guide arms 9 press the cleaning systems 7 into contact with the mirrors M to allow the simultaneous cleaning of all the lines of solar reflectors 11.

In the case of FIG. 13C, the cleaning is finished, the cleaning systems 7 are raised and can be dismantled if necessary. It is then possible to switch to cleaning another solar field.

FIG. 14 also illustrates another example of a supporting structure 1 according to the invention.

The supporting structure 1 comprises a chassis 6 consisting of a plurality of tubes 30, for example with a diameter of approximately 90 mm, connected to each other by flanges 31. The overall buckling of the chassis 6 is counterbalanced by guy lines 32 , made in particular of steel, and having for example a diameter of about 40 mm.

The chassis 6 is supported on the ground by means of guide wheels 4a, inflatable and adaptable to uneven ground, by means of its lateral structures 3.

All of the constituent elements of the chassis 6 can be assembled by means of flanges 31, the latter nevertheless comprising two sets of specific flanges 33 making it possible to distinguish a central part P2 forming a modular zone and end parts Pl and P3, as explained previously with reference to FIG. 5.

Thus, the support beam 2 can be constituted by segments of beams flanged together, making it possible to adjust the width of the support structure 1 by simple assembly / disassembly and thus to obtain a versatile solution from simple and standardized elements. .

The constituent elements of the chassis 6 can for example be made of steel, in particular of S235 type steel, galvanized or hot painted, or even any conventional structural steel protected from external corrosion, for example by painting, galvanizing, among others. The height of the support beam 2 can be managed for example by bolted or pinion / rack construction.

Advantageously, the maintenance in a substantially horizontal plane of the support beam 2 is obtained by the mechanical dimensioning of the chassis 6, with the presence of central stays 32 and a resumption of forces on the edges or by the presence of a structure similar to that of a trellis supporting the R receptor.

FIG. 15 also illustrates the possibility for the support structure 1 according to the example of FIG. 14 to allow maintenance intervention on the receiver R of the solar power station 10.

Thus, as previously described with reference to FIG. 4, the support structure 1 comprises a maintenance system 17 for the receiver R which is capable of deploying vertically above the support beam 2 to reach the receiver R. In other words, the support beam 2 can serve as a platform or support for the deployment of the maintenance system 17 of the receiver R.

As described above with reference to FIG. 4, this maintenance system 17 can for example be a cleaning system 17 for the window V placed at the bottom of the receiver R.

Of course, the invention is not limited to the exemplary embodiments which have just been described. Various modifications can be made by those skilled in the art.

Claims (15)

1. Supporting structure (1) for solar power station (10) comprising a plurality of solar structures (11), characterized in that it comprises: - a frame (6) comprising a raised central support beam (2) and two lateral structures (3), respectively located at each of the two ends (2a, 2b) of the support beam (2) and configured to come from both sides and d other of the plurality of solar structures (11) so that the frame (6) spans the plurality of solar structures (11), - displacement means (4) of the support beam (2) relative to the plurality of solar structures (11), formed at least in part at each of the two lateral structures (3) and configured to be at least in part in contact with the ground and located on either side of the plurality of solar structures (11), - at least one support device (5), carried by the support beam (2), of at least one cleaning system (7) of fouled surfaces (M) of solar structures (11) and / or of a system maintenance (8) of solar structures (11). 2. Supporting structure according to claim 1, characterized in that it comprises at least one cleaning system (7) of fouled surfaces (M) of solar structures (11), and in that said at least one support device ( 5) comprises means for guiding (9) the movement of said at least one cleaning system (7). 3. Supporting structure according to claim 1 or 2, characterized in that it comprises at least one cleaning system (7) of fouled surfaces (M) of solar structures (11), and in that said at least one device for support (5) comprises means (12) for spraying a cleaning liquid (E), in particular water, on the dirty surfaces (M). 4. Supporting structure according to one of the preceding claims, characterized in that the displacement means (4) of the support beam (2) comprise guide wheels (4a) secured to each lateral structure (3). 5. Supporting structure according to claim 4, characterized in that the displacement means (4) comprise at least one guide rail (4b) associated with each lateral structure (3), on either side of the plurality of structures solar panels (11), each guide rail (4b) cooperating with the guide wheels (4a) fixed on the lateral structure (3) associated with said guide rail (4b) to allow the displacement of the support beam (2) relative to the plurality of solar structures (11). 6. Support structure according to claim 4, characterized in that each lateral structure (3) comprises guide wheels (4a) which can be oriented, in particular four guide wheels (4a), configured to be in direct contact with the ground. 7. Supporting structure according to claim 6, characterized in that it comprises at least one positioning element (20), in particular two positioning elements (20) respectively at each end (2a, 2b) of the support beam (2) , configured to cooperate with at least one positioning rail (22) fixed to a post (21) of the receiver (R) of the solar power station (10) located on one side of the plurality of solar structures (10), in particular with two positioning rails (22) respectively fixed to a first post (21) of the receiver (R) of the solar power station (10) located on one side of the plurality of solar structures (10) and to a second post (21) the receiver (R) of the solar power station (10) located on the other side of the plurality of solar structures (10), to allow the displacement of the support beam (2) relative to the plurality of solar structures (11). 8. Supporting structure according to one of claims 4 to 7, characterized in that each lateral structure (3) comprises a motorization system allowing the movement of the guide wheels (4a). 9. Support structure according to any one of the preceding claims, characterized in that said at least one support device (5) is carried by the support beam (2) by means of lifting means (15) fixed to the beam support (2), in particular a lifting winch (15) or a chain hoist. 10. Support structure according to any one of the preceding claims, characterized in that it comprises a maintenance system (17) of the receiver (R) of the solar power station (10), in particular a maintenance system (17) deployable vertically above the support beam (2) and extending from the support beam (2). 11. Support structure according to any one of the preceding claims, characterized in that the frame (6) of the support structure (1), in particular the support beam (2), has a modular dimensioning to adapt to the number of structures solar panels (11), in particular a modular width as a function of the number of lines of solar structures (11). 12. Supporting structure according to any one of the preceding claims, characterized in that it comprises means for supplying cleaning liquid (14), in particular a tank for cleaning liquid (14) and / or a circuit for supply (24) of cleaning liquid connected to one or more cleaning systems (7), supported by the frame (6) of the support structure (1). 13. Solar power station (10), characterized in that it comprises a plurality of solar structures (11) and a support structure (1) according to any one of the preceding claims, the support structure (1) being able to allow the cleaning and / or maintenance of the plurality of solar structures (11). 14. Solar power plant according to claim 13, characterized in that it comprises a supporting structure (1) according to claim 6 and a receiver (R) comprising a post (21) on which is fixed at least one position sensor (23 ) able to detect the presence of the supporting structure (1) to allow its guidance during its 5 displacement relative to the solar structures (10). 15. Method for cleaning and / or maintenance of a plurality of solar structures (11) of a solar power station (10), characterized in that it is implemented by means of a support structure (1 ) according to any of 10 claims 1 to 12, and in that it comprises the step of displacing the supporting structure (1) relative to the plurality of solar structures (11) by means of displacement (4) at least partially at ground contact.