Aerothermal solar panel with plant-based insulation

Abstract

A flat-plate aerothermal solar panel equipped with means for fixing to a building to be heated, comprising a rigid frame (100) arranged around the periphery of said panel and surrounding an enclosure (1) comprising, successively from front to back and spaced apart, the following components: - a pane (2) of light-transparent material forming a front wall, - a heat absorber (3) formed of a metallic sheet, - an insulating layer (4) forming a rear wall, the enclosure (1) of said panel being equipped with side walls formed by partitions (5) rising from the periphery of the insulating layer (4), said insulating layer and said partitions comprising at least one insulating material of plant origin. The insulating material may be natural cork, expanded cork, or a combination thereof.

Description

Title of the invention: Aerothermal solar panel with plant-based insulation

[0001] The present invention belongs to the field of solar energy capture techniques, and more particularly to the field of thermal solar panels.

[0002] It relates to an aerothermal solar panel used for heating a building, having improved performance thanks to an enclosure whose base and side walls are thermally insulated by a material of plant origin.

[0003] Reducing energy consumption is now a universally recognized imperative, and numerous systems are proposed to conserve resources, including technologies that utilize solar energy. The most widespread of these rely on converting solar radiation into electrical energy using photovoltaic panels. Less frequently mentioned are technologies employing solar thermal collectors, which aim to absorb solar energy in the form of heat, which is then transferred to a heat transfer fluid. It is known to integrate such collectors into an enclosed space to create solar thermal panels that can be installed in a fixed or adjustable manner on a building to be heated, or in its immediate vicinity.

[0004] A thermal panel typically comprises a transparent pane of glass through which sunlight enters the panel, a collector that transforms solar radiation into heat and transfers it to a heat transfer fluid, and an insulating backing to prevent heat loss. The panel has an inlet and an outlet allowing the circulation of the heat transfer fluid. When the panel is exposed to sunlight, the collector heats up due to the energy input from the radiation (primarily visible light, UV, and infrared). The heat transfer fluid circulating within the panel recovers the heat energy and transfers it to a room to be heated.There are several types of thermal collectors, among which glazed collectors are the most common in the residential sector, while unglazed collectors are used for heating swimming pools, and evacuated tube collectors are dedicated to applications in extreme conditions.

[0005] Solar thermal panels are primarily used to produce domestic hot water. They operate with a liquid heat transfer fluid, for example, water, water-glycol mixtures, or others. In some cases, they can also supply a domestic heating system. Manufacturing these systems is expensive, and their installation requires significant building modifications. Therefore, their use is recommended for dwellings or service premises occupied by permanence, the energy savings achieved in this case being able to justify the initial equipment expenses.

[0006] Solar panels in which the heat transfer fluid is air, also called aerothermal panels, are less common. However, they offer numerous advantages. They operate simply, as the heat transfer fluid is ambient air heated by direct contact with a plate acting as an absorber, before being injected into the building's heating system. They are easier to manufacture than water-based panels, their installation on buildings is straightforward, and their maintenance is minimal. In particular, unlike water-based systems, they do not require the use of antifreeze or a self-draining device to protect them from freezing. With a moderate manufacturing cost, this type of solar panel is attractive, especially for maintaining a comfortable temperature and reducing humidity in intermittently occupied dwellings, or as a supplement to other heating methods, particularly during the shoulder seasons.In the context of the ecological transition and the development of renewable energies, these aerothermal solar panels are destined to be used more and more.

[0007] Various models of aerothermal panels have been proposed, with variations designed to optimize their performance. Firstly, since air is a less efficient heat transfer fluid than water, efforts have been made to promote heat transfer. One solution is to increase the duration and / or length of the air's path within the collector, allowing it to accumulate a maximum amount of heat. To achieve this, the inside of the collector can incorporate physical obstacles that force the air to take detours.

[0008] For example, document FR 2 865 269 describes an air-based solar collector consisting of a box with a base plate acting as an absorber and a transparent pane of glass between which air circulates, following a path dictated by staggered metal partitions. The prolonged circulation of the gas along the partitions promotes heat transfer. An insulating polyurethane foam panel is attached beneath the absorber. However, since the hot air is in contact with the glass, some of the heat is lost to the outside. To address this drawback, document FR 2 975 759 proposes an air-circulating solar collector with an absorbent wall placed between the glass and the base of the box so as to delimit two compartments and create, on the one hand, an insulating layer of still air and, on the other hand, a volume in which the air to be heated circulates. No insulation of the box is provided.Document FR 3 098 572, for its part, recommends a solar thermal collector comprising a hermetically sealed enclosure filled with stagnant air, delimited by the absorber and the glass joined together. The absorber has a base extended by side walls, which increases the absorber's exposure surface area, and thereby... thermal efficiency.

[0009] Furthermore, easy-to-assemble structures have been sought. To this end, most known panels are designed with a box-like structure, the base of which is surrounded by side walls formed from joined profiles, or made in one piece by forming a metal plate. FR 2 908 870 describes such a configuration and also proposes a transparent element having an inverted U-shaped cross-section, the flanges of which cover at least the absorber assembly. The absorber assembly is generally placed above insulation located in the base of the box.

[0010] Finally, whatever the structure and arrangement chosen for the air panels currently available, it is necessary to use different fasteners to hold together the absorber, the glazing and the bottom of the panel, which complicates their assembly, lengthens assembly time and manufacturing costs.

[0011] None of these approaches takes into account the heat loss occurring through the lateral edges of the panels. However, the edges represent a significant exchange surface. Indeed, for a square panel of 1 m², with a thickness of 12 cm, the lateral surface area of ​​the perimeter is 0.48 m², or about half the surface area of ​​the panel. For a rectangular panel of 2 m² and 10 cm thick, the lateral surface area is still 0.6 m², or 0.3 m² per m² of frontal surface. The side walls thus constitute heat exchange zones whose presence significantly affects the efficiency of the panel. Admittedly, document FR 2 975 759 describes the use of thermally insulating plastic parts for fixing the thin wall acting as an absorber to the wall of the enclosure, so as to create a thermal break. However, no provision for insulating the edges of the panel as a whole is envisaged.

[0012] Furthermore, the materials used as insulation on the back of the panel are synthetic materials, such as polymers, which are likely to emit toxic volatile organic compounds (VOCs) that have a negative impact on health, in quantities that increase with the temperature inside the solar panel. These compounds will then be released into the atmosphere, particularly into the heated room, and inhaled by the people present.

[0013] Furthermore, the use of synthetic materials must be reconsidered in light of new standards aimed at reducing the environmental footprint of buildings. The search for alternatives to conventional materials must now be part of a comprehensive sustainable development approach, encompassing components, manufacturing, implementation, and recycling. Currently available aerothermal panel models are, in several respects, at odds with environmental concerns.

[0014] The present invention aims to remedy the drawbacks of systems existing systems and to meet the objectives outlined above. To achieve this, it proposes an air-based solar panel with an insulating structure on both the base and side walls, this structure being made from a plant-based material. It provides a large thermally insulated surface area with a bio-based material, which simultaneously secures the absorber and the front glazing. The component parts are held together by a frame. This configuration, made possible by the use of a healthy, bio-based insulation, ensures increased thermal efficiency of the panel while reducing the number of parts to be assembled. It also allows for a thinner panel, making it more aesthetically pleasing on a facade or roof. It should be noted that in the following text, and unless otherwise indicated, the terms "insulating" and "insulation" refer to the thermal aspect.

[0015] More specifically, the invention relates to a flat aerothermal solar panel equipped with means for fixing to a building to be heated, comprising a rigid frame arranged around the periphery of the panel, and surrounding an enclosure comprising, successively from front to back and spaced apart from each other, the following parts: - a window made of a light-transparent material forming a front panel, - a heat absorber made of a metallic foil, - an insulating layer forming a back wall, the enclosure being equipped with side walls formed by partitions rising from the perimeter of the insulating layer, said insulating layer and said partitions comprising an insulating material of plant origin.

[0016] The solar panel according to the invention is intended to equip a building, with a view to heating its interior spaces, and secondarily to cooling them and ensuring their ventilation, as will be explained later. The buildings concerned can be of any type, in particular dwellings, apartment buildings or individual houses, business premises belonging to the industrial, commercial or administrative sectors, open to the public such as schools, nurseries, etc. They can be occupied intermittently or continuously over the course of months or during a circadian cycle. They have a facade or a section of roof facing south, and if possible due south, so as to offer the panel maximum exposure to the sun. The panel will be fixed to the building by means known per se, for example by means of hooks which will be screwed onto rails previously installed on the facade or roof to be equipped.

[0017] The solar panel according to the invention is of the flat glazed type, typically square or rectangular. In the following description, the solar panel will be considered as it is once installed, with a rear face facing the building to which it is attached, and a front face facing the surrounding space, the front and rear faces being inscribed in parallel planes. The rigid frame is arranged around the periphery. The panel has four lateral edges, which are respectively the right, left, top, and bottom edges. The frame is considered rigid insofar as it is capable of resisting deformation and maintaining the panel's structure in the intended and suitable conformation for its use.

[0018] The frame surrounds an enclosure in which the process of capturing and transferring heat energy takes place. At the front, it comprises a pane of light-transparent material forming the front wall of said enclosure. It should be noted that this pane also forms the front wall of the panel, regardless of the frame's thickness. The pane can be made of any material that transmits sunlight without being affected by the received radiation or the generated heat (in particular, deformation and fading). It can be made of glass, a synthetic polymer such as polycarbonate, or other materials. Tempered glass, which ensures physicochemical stability and safety, is preferred whenever possible.

[0019] Beneath the glass and at a distance from it, there is a heat absorber. It is known to use a metal plate with high thermal conductivity, treated to absorb light by heating up. Preferably, a thin plate is used, for example, a sheet of aluminum, coated with a matte black lacquer or a selective absorbing coating, or treated by electroplating, allowing it to collect the heat resulting from solar radiation.

[0020] This sheet can be flat or have more or less pronounced reliefs, such as folds, undulations, hollows and protrusions, or other asperities. Preferably, the absorber has the conformation of a flat sheet, which is simple to implement and does not add thickness to the assembly. The glass and the absorber are placed at a distance from each other, that is to say, with a certain gap, and the space between them constitutes a chamber for capturing the light energy that has passed through the glass, which is absorbed as heat by the metal sheet. This heat is then recovered by the air moving in contact with the absorber, in a circulation chamber formed between the absorber and an insulating structure.

[0021] Indeed, behind and at a distance from the absorber, there is an insulating layer that forms the rear wall of the enclosure (and also the rear wall of the panel, disregarding the frame thickness). By insulating layer, we mean a simple or composite structure capable of at least thermally insulating the compartment it delimits. In an original design, the enclosure has side walls formed by partitions rising from the perimeter of the insulating layer, which also have thermal insulation properties. The partitions are conveniently oriented perpendicular to the plane of said layer and thus form an air circulation chamber, closed at the front by the absorber. This arrangement makes it possible to use the heat generated by the absorber with high efficiency, without significant loss. neither towards the rear nor from the sides. As the insulating elements (insulating layer and partitions) are in direct contact with the circulation chamber and therefore subjected to high temperatures during the operation of the solar panel, it is essential to avoid any emissions and therefore the use of synthetic materials usually employed as insulation is prohibited here.

[0022] It became apparent that materials made from cork were capable of meeting this objective, due to their multiple properties which make them compatible with the intended application, and even offer unexpected advantages. Indeed, cork is a completely natural, renewable, biodegradable, and non-allergenic material. At the same time, it possesses characteristics that are highly desirable for use in solar panels: it is incompressible, rot-proof, impermeable to liquids, resistant, and lightweight. Above all, it is a thermal and acoustic insulator, and also has good thermal inertia, which helps to mitigate temperature variations. It offers extreme durability, as it is resistant to frost, rodents, and insects.

[0023] It can be used in block form, but it is more advantageous to grind it to obtain granules that can then be compressed into ready-to-use sheets or cut to the desired dimensions. It is important to emphasize that it is the cork sap, rich in suberin, that allows the particles to agglomerate without the addition of glue or any other binder.

[0024] There are two types of cork: natural cork, or white cork, and expanded cork, also called black cork. Natural cork undergoes no treatment other than scalding after harvesting. Expanded cork is obtained by a process that involves heating cork granules with steam, causing them to expand with air and fuse into a compact block. In the present invention, either of these two types of cork can be used as an insulating material. They can also be combined in a composite material, for example, by layering successive coats of each, or in any other combination. However, the use of expanded cork on the surface of insulating elements should be avoided, as it tends to emit dust that could be dispersed into buildings and inhaled.

[0025] Thus, according to a preferred feature of the panel of the invention, at least one insulating material of the insulating layer and partitions is selected from natural cork, expanded cork, or a combination thereof. In this way, the circulation chamber is largely delimited by a healthy, bio-based material, while perfectly meeting the technical requirements expected for solar panels.

[0026] According to an advantageous feature of the invention, the insulating layer forming the rear wall of the enclosure (and the panel) comprises a rigid support plate against which a layer of said insulating material rests. The support plate allows The plate protects its outer surface from mechanical damage and also supports the insulating layer from behind, stiffening the back wall. The presence of this plate offers another advantage related to the panel assembly method. As will be detailed later, the peripheral frame holds the enclosure components together by clamping them between jaws: the areas subjected to the jaw pressure must offer sufficient crush resistance, which a simple layer of agglomerated cork lacks. The support plate must be thin to minimize its size, but rigid enough to prevent the cork or other insulating material it reinforces from flexing. It can be made of a synthetic material, provided it is not subjected to high temperatures, being separated from the hot circulation chamber by the insulating layer.One can thus use a PVC (polyvinyl chloride) sheet with a thickness of around one millimeter, against which is applied a layer of cork with a thickness ranging from one to several centimeters, for example between 1.5 cm and 3 cm.

[0027] Since the panels generally have a surface area greater than one m2, the rigidity of the panel can be usefully increased by means of cross bars fixed to the back wall, either on the outside of the panel, or in an original way on the inside, by assembling in the thickness of the insulating layer forming the back wall, a long and thin element, such as a metal strip.

[0028] According to a particular embodiment of the invention, the insulating layer may thus comprise at least one reinforcing strip placed between the support plate and the layer of insulating material. The rigidity provided by the support plate is thus reinforced by one or more strips, for example three strips, which are long, flat, thin, and narrow. They extend transversely between said support plate and the insulating layer, without reaching the edges of the insulating layer, so as to be embedded within the insulating layer. Advantageously, they may be provided with a rib rising perpendicularly to their general plane, and thus adopt the shape of a profile with a T-shaped cross-section. The base of the T can then be used to stabilize the insulating layer when the latter is made up of several segments.

[0029] The partitions are preferably made of the same material as the insulating layer of the rear wall of the enclosure, although this is not mandatory. As previously mentioned, they are installed around the entire perimeter of the insulating layer, and more specifically of the insulating layer to which they are bonded. They form the side walls of the enclosure and therefore extend to the front wall of the enclosure, i.e., to the transparent window. Interestingly, they take the form of battens with a regular elongated longitudinal shape and a rectangular (or possibly square) cross-section. Each batten forms one of the side walls and is joined at its ends to the battens of the adjacent walls. One of the The short ends of the battens are in contact with the insulating layer, while the other short end is in contact with the glass. Assembly can be done by any means, for example gluing, mortise and tenon joints, or other methods, but in a particularly interesting way, the different elements will be secured by clamping between jaws fitted to the peripheral frame.

[0030] Thus, according to a feature of the solar panel which is the subject of the invention, the partitions can be formed of four rectangular cross-section battens joined at their ends, each having a first small side placed in contact with said insulating layer, at the edge thereof, and a second small side joined in a contiguous manner with the transparent glass.

[0031] According to a particular feature of the invention, the partitions comprise means for maintaining the transparent glass at a predetermined fixed distance from the insulating layer, and consequently also at a certain distance from the absorber sheet. This latter distance corresponds to the depth of the collection chamber.

[0032] Thus, elements acting as lateral insulation for the enclosure also ensure the correct positioning of the glass at the front of the panel. Various means can be used, such as shims placed at intervals, movable cleats around an axis that can be oriented to lock the glass in place, or other means known to a person skilled in the art. In an original approach, the second short side of the partitions can be provided with a recess along their inner edge; in other words, a surface set back from the surface of said short side and parallel to it, allowing the glass to rest against it. The glass can then be fixed in this position, again utilizing the structure of the peripheral frame and its clamping jaws.

[0033] Thus, according to an advantageous embodiment of the invention, the second short side of the partitions has a step made continuously along their inner edge, said step receiving support from a perimeter area of ​​the transparent glass.

[0034] According to a similar approach, the partitions of the solar panel according to the invention advantageously include means for maintaining the absorber at a predetermined fixed distance from the insulating layer, and consequently also at a certain distance from the glass at the front of the panel. These distances are determined during the design of the panel, whose proper functioning they affect, since they correspond respectively to the depth of the circulation chamber and that of the collection chamber. By way of example, the circulation chamber delimited by the insulating layer and the absorber sheet can have a depth of 20 mm to 30 mm, while the absorber sheet and the glass delimit a collection chamber of 4 mm to 6 mm. depth.

[0035] Various means can be used by a person skilled in the art, but preferably, insulating partitions are used to hold the absorber in direct contact. For this purpose, according to a preferred embodiment, the partitions have a continuous groove parallel to the general plane of the panel, into which a perimeter section of the absorber is inserted. Cork is easily suited to the cutting of such a groove, which will be made prior to the assembly of the partitions. A section a few millimeters to one centimeter wide, running along the entire perimeter at the edge of the absorber sheet, is sufficient to hold it in place.

[0036] The solar panel of the present invention comprises a rigid frame arranged around the periphery of said panel and surrounding the enclosure described above. In an advantageous embodiment, the frame cooperates with the parts forming the enclosure so as to hold them together by clamping. It is shaped to fit around the enclosure, bearing against the side walls of the enclosure and, by means of extensions with which it is equipped, against the margins of the front and rear faces of the enclosure. In other words, it has a straight, vise-like cross-section whose two jaws, front and rear, compress the parts of the enclosure and hold them fixedly assembled against each other. This assembly is made without the addition of glue, either on the glass or on the absorber sheet, which allows for in-situ repairs on the frame without having to disassemble and return the panel to the factory in case of breakage.This also eliminates drying time during manufacturing.

[0037] According to a preferred feature of the solar panel of the present invention, the rigid frame surrounding the enclosure can thus include front and rear extensions forming jaws which respectively overhang the margin of the front and rear walls of the enclosure, the parts of the enclosure being held together by the pressure exerted by said jaws.

[0038] The frame of the solar panel according to the invention can be made of various materials, such as wood or metal, for example, an aluminum profile. It can conveniently consist of two elements: a basic frame completed by a glazing bead that holds the glass in the rebate of its support (here, the recess in the cork partition). The frame can, for example, surround the four side walls of the enclosure and have a rear extension covering the edge of the rear wall, while a glazing bead, completing the panel assembly with an elastic clip, has a front extension covering the edge of the front wall. The front and rear extensions can conveniently be bent at their ends to form a return through which pressure is applied to the front and rear walls to tighten the assembly.

[0039] That is why, according to a particular embodiment, the frame of the solar panel The object of the present invention is a metal or wood profile formed i) of a frame laterally encircling the enclosure and comprising said rear extension, and ii) of a glazing bead fixed within said profile and comprising said front extension, each of said front and rear extensions being provided with a curved return to bear against said front or rear wall, respectively. The front and rear returns may advantageously be equipped with a continuous seal along the line of contact, suitable for preventing rainwater infiltration, avoiding unwanted friction, and absorbing vibrations.

[0040] The aerothermal solar panel as described above offers a novel, high-performance solution, the manufacture of which is easier compared to previously known panels. Indeed, the assembly of conventional systems requires several additional fasteners to hold together the absorber, the glazing, and a casing forming the base of the panels. Gluing the glazing followed by drying periods significantly lengthens the process. In contrast, in the panel according to the invention, the absorber sheet is supported directly by the insulating partitions, which also serve as supports for the glazing, the whole assembly being mounted in a frame, without screwed or glued joints. Consequently, a considerable time saving is achieved. The thermal performance of the panel according to the invention is also high thanks to the use of cork as insulation for the back wall as well as the side walls of the energy collection chamber.

[0041] Since the primary role of the aerothermal solar panel according to the invention is to supply hot air to a building, it is necessary to organize the circulation of air from the outside atmosphere through the enclosure, and then into the interior space of the building. Therefore, according to a first embodiment of the invention, said solar panel includes means allowing the circulation of air through the panel, from the outside environment to the interior of the building, comprising: - an air inlet opening made in the lower lateral part of the panel through the frame and the adjacent partition of the enclosure, opening into the space between the insulating layer and the absorber, constituting a circulation chamber, and - an air outlet duct located in an opening made in the upper part of the rear wall, leading into the interior of the building.

[0042] The problem of condensation forming in the collection chamber between the glass and the absorber sheet is well known. It can be solved here simply, without resorting to complex airtight assemblies. For this purpose, the collection chamber is designed to communicate with the outside, so that moisture does not accumulate there, or, if necessary, so that the condensate can drain away by gravity.

[0043] It can therefore be provided, according to the invention, that the air inlet opening is made to open partly into the space located between the transparent window and the absorber, constituting a collection chamber.

[0044] According to one embodiment, air circulation can occur from the rear of the panel. In this case, the solar panel according to the invention may include means allowing air circulation through the panel, from the outside environment to the inside of the building, comprising: - an air inlet opening made in the lower part of the rear wall of the enclosure through the insulating layer, leading into said circulation chamber, and - an air outlet duct located in an outlet opening made in the upper part of the rear wall, leading into the interior of the building.

[0045] To avoid condensation, as explained previously, it can be provided that the absorber has at least one perforation in its lower part, allowing air to circulate from the circulation chamber to the collection chamber.

[0046] Furthermore, it appeared that the air in the capture chamber heated up at least as much as the air in the circulation chamber, with the drawback of heat loss through the front of the panel. This well-known phenomenon finds an original solution in a particular embodiment of the invention, in which air circulation is organized through the capture chamber. To this end, one or more perforations, which can be made by drilling or punching, are made in the absorber sheet, in a high position, so as to allow air to pass from the capture chamber to the circulation chamber. The perforations can advantageously be located in an area near the air outlet duct, so as to promote the intake and transfer of the already warm air directly into the building.The airflow entering the chamber and diverted towards the capture chamber must remain moderate compared to the main flow passing through the circulation chamber. It can be in the range of 5% to 15%, the adjustment being achieved by the number and size of the perforations. For example, two to five perforations of identical or different diameters, ranging from 1 cm to 5 cm, can be made.

[0047] Thus, in the solar panel according to the invention, the absorber may include at least one perforation in its upper part, allowing air to circulate from the collection chamber to the circulation chamber with a flow rate proportional to the number of perforations and their size.

[0048] The air solar panel just described can be passive, that is, it uses natural convection: hot air rises naturally and creates air movement. It can also force air circulation by means of mechanical ventilation. The solar panel according to the invention will preferably be equipped with a fan, in which case a power supply will be provided, either by connection to the grid or by means of an associated photovoltaic sensor. It can be switched on on demand, via a user interface. It can also be equipped with a automated management module, which can be configured by a user.

[0049] According to an interesting feature, the solar panel according to the invention further comprises: - a fan capable of drawing air from the inlet opening to the outlet duct through the enclosure, - optionally, means for powering said fan, - an electronic management and control module, - a user interface.

[0050] It is advantageous to activate the ventilation system when the temperature difference between the inside and outside warrants it. It should be noted that while the primary purpose of a solar panel is to contribute to heating a room, it can also effectively cool said room when the air passing through the panel is sufficiently cold. Temperature sensors can be installed in suitable locations, generally within the panel enclosure and in a room of the building, and connected to the electronic module.

[0051] Therefore, the solar panel according to the invention may further comprise two temperature probes configured to periodically record the temperature prevailing respectively within the panel enclosure and in the equipped building, the electronic module being configured to receive and compare the temperature data provided by said probes, and - If the temperature inside the enclosure is higher than the building temperature by a predetermined setpoint, activate the fan to blow in warm air. - if the temperature in the enclosure is lower than that of the building by a predetermined setpoint value, activate the fan to blow in fresh air.

[0052] Aerothermal solar panels have a simple structure and few wear parts. However, their integration into facades is often considered unsightly by users. It is therefore often proposed to integrate them directly into the cladding or the building's exterior insulation. But this limits access and maintenance, which can cause problems if one of the panel components fails. This problem is exacerbated when the panels are installed at a height.

[0053] To overcome this drawback, the present invention proposes a system that integrates all the short-life components directly into a blowing device. Thus, the active and / or moving parts subject to wear (fan, electronics, temperature sensors) are easily accessible for maintenance or repairs, while the inert and less fragile parts (frame, insulation, absorber, glass) are located outside the building structure.

[0054] The solar panel just described makes it possible to obtain a performance It has high energy efficiency despite its thin profile, which makes it more aesthetically pleasing. As a result, it is well-received by potential users, especially since it is very easy to maintain, as no liquid fluids or batteries need servicing.

[0055] The present invention will be better understood and relevant details will become apparent, in the light of the description which will be made of embodiments, in relation to the attached figures.

[0056] [Fig-1] is a general view of an air solar panel according to the invention installed on the facade of a building.

[0057] [Fig.2] is a schematic front view of an air solar panel according to the invention.

[0058] [Fig. 3] represents an air solar panel according to the invention, seen in cross-section

[0059] [Fig. 3] represents an air solar panel according to the invention, seen in cross-section transversal.

[0060] [Fig.4] shows a detail of the same solar panel.

[0061] [Fig.5a] is a front view of a first absorber equipping a panel according to the invention.

[0062] [Fig.5b] is a front view of a second absorber fitted to a panel according to the invention.

[0063] [Fig.6] is a bottom view of the frame of a panel according to the invention.

[0064] EXAMPLE 1: General presentation of a building equipped with a panel solar

[0065] The solar air panels according to the invention are intended for installation on facades or roofs. They heat and secondarily ventilate dwellings or commercial premises. As shown in [Fig. 1], air circulates through the panel, from the exterior environment Ext to the interior Int of the building, via an air inlet 20 located in the lower lateral part of the panel, or at its rear, and opening into a circulation chamber 21. The air inlet is usefully equipped with an insect screen. The heated air then passes through an air outlet 30 located in an outlet 31 in the upper part of the rear wall, leading to the interior of the building.

[0066] The panels can be mounted on facades by overlaying, integrated into external insulation, or into cladding. On roofs, installation is carried out by overlaying using two or three rails, in a manner known per se. They can be fixed by any available means. According to the diagram shown in [Fig. 2], a panel is fixed by its frame 100 using eight galvanized steel brackets 111. The fixing points can be adjusted along the frame 100, and also on the wall thanks to oblong holes on the brackets.

[0067] EXAMPLE 2: Structure and arrangement of an aerothermal solar panel

[0068] The panel model illustrated below is rectangular, dimensioned as follows, it being understood that all values ​​are given as examples only and can be modified without departing from the scope of the invention. - Total dimensions: 2000 mm x 1000 mm x 73 mm - Total area: 2 m2 - Capture area: 1.9 m2 - Total mass: 40 kg

[0069] The structure of such a panel, shown in Figures [Fig. 1] and [Fig. 2], comprises a frame 100 surrounding an enclosure 1. The enclosure 1 has at its rear an insulating layer 4 which is provided with partitions 5 forming the side walls of the enclosure 1. The insulating layer 4 consists, on its outer side, of a 1 mm thick white PVC plate 6, on which rests a 20 mm thick insulating layer 7 made of cork. It incorporates three 1 mm thick, T-shaped aluminum strips (not shown), reinforcing the rigidity of the enclosure 1 and the support of the insulating layer 7, which in this case is composed of four juxtaposed segments.

[0070] The insulating layer 7 and the partitions 5 are made from agglomerated natural cork panels cut to the required dimensions. The cork panels can be made from cork waste and / or crushed cork particles of various sizes, generally ranging from a few millimeters to one centimeter, naturally agglomerated by the suberin present in the cork. For example, crushed cork with a particle size distribution of 98.5% between 2 mm and 14 mm can be used. The panels used comply with the requirements set by Community regulations, identifiable by the CE marking, for their performance in terms of thermal resistance, thermal conductivity, reaction to fire, water absorption, resistance to vapor diffusion, compression and bending, as well as dimensional stability. In particular, they have a thermal resistance of 0.444 m².K / W.

[0071] The partitions 5 are made by cutting four rectangular cork battens 51. They are 20 mm thick and 28 mm high, joined end to end. One short side 52 rests on the perimeter of the insulating layer 7. The second short side 53 of the battens 51 has a notch 8, running along the entire inner edge and providing a bearing surface for a pane of tempered glass 2, with a thickness ranging from 3 mm to 10 mm, but generally between 3.5 mm and 6 mm. The pane of glass 2 rests around its entire perimeter, by a perimeter area 23 of 5 mm to 15 mm, here 9 mm, on the bearing surface formed by the notch 8. An expansion gap 25 of approximately 2 mm is left at the bottom of the notch 8.

[0072] The battens 51 forming the partitions 5 also have a groove 54, continuous around its entire perimeter and parallel to the general plane of the panel. This groove 54 A 3-piece absorber, consisting of a 1 mm thick black lacquered aluminum sheet (or 0.5 mm if treated with a selective coating, such as Mirotherm, marketed by Alanod), is held in place. The groove 54 is 10 mm deep, so that it notches the battens 51 to half their thickness, thus avoiding excessive weakening of the partitions 5 and properly securing the absorber sheet 3. Its height is 1.5 mm, slightly greater than the thickness of the absorber 3, facilitating the insertion of a perimeter strip (33) for the absorber. An expansion gap 55 of approximately 2 mm is left at the bottom of the groove 54.

[0073] The enclosure 1 thus constituted comprises a circulation chamber 21, delimited by the insulating layer 7 and the absorber sheet 8, separated by a distance of 28 mm, and a collection chamber 22 between the absorber sheet 8 and the transparent glass 2, separated by a distance of 5 mm. The enclosure 1 thus has a thickness, excluding the frame, not exceeding 60 mm.

[0074] Ideally, an insulating film against infrared radiation, for example a PET (polyethylene terephthalate) film, is inserted between the thermally insulating layer 7 and the support plate 6. This limits heat loss by radiation through the bottom of the enclosure 1. Note that this has no impact on heat transfer by conduction, which is a separate phenomenon.

[0075] The frame 100, as shown in the figures, surrounds the four walls of the enclosure 1 around its entire perimeter and has a straight, vise-like profile with two jaws gripping the enclosure 1, one at the front and one at the rear. One jaw consists of a front extension 101, overhanging the edge of the front wall of the enclosure 1, the end of which has a curved return bearing against said front wall via a front seal 103. The front seal 103 ensures sealing and resilience by preventing friction between the metal of the front extension 101 and the glass of the window 2. The other jaw consists of a rear extension 102, overhanging the edge of the rear wall of the enclosure 1, the end of which has a curved return bearing against said rear wall. The rear return incorporates a rear seal 104 ensuring the seal between said rear extension 102 and the PVC plate 6.In this way, the parts of enclosure 1 are held together by the pressure exerted by said front and rear extensions.

[0076] In practice, the frame is formed of a chassis 110, prefabricated in the workshop, laterally encircling the enclosure 1 and including the rear extension 102. For the assembly of the panel, the rear seal 104, the PVC plate 6, the insulating layer 7, the partitions 5 holding the absorber sheet 3, then the glass 2 and the front seal 103 are successively placed in the frame 100 placed horizontally on a platform. A glazing bead 120 including the front extension 101 is then added, which is fixed by clipping onto the profile.

[0077] According to a first variant, the air circulation in enclosure 1 is carried out from An air inlet 20 is provided in the lower lateral part of the frame 100 and passes through the partition 5. As shown in Figures [Fig. 5a] and [Fig. 6], the air inlet 20 opens into the circulation chamber 21 and partially into the collection chamber 22. In the absorber sheet 3, three perforations 32 are made in the upper part, at the level of the air outlet 31. In this way, most of the air flows through the circulation chamber 21 and a fraction of the flow passes into the collection chamber 22.

[0078] According to a second embodiment, air circulation in enclosure 1 occurs through an air inlet 20' located in the lower part of the rear wall of enclosure 1. The inlet 20' passes through the insulating layer 4 and opens into the circulation chamber 21 in its lower position. To allow air circulation from the circulation chamber 21 to the collection chamber 22, as shown in Figures [Fig. 5b], the absorber 3 is provided with three perforations 32' in its lower part.

[0079] In both cases, the air circulates to an outlet 31 made in the upper part of the rear wall, and flows through the outlet duct 30, with a diameter of 125 mm, passing through the insulating layer 4.

[0080] The panel as described above can operate as a passive system, but it can also include a fan capable of propelling air from the inlet orifice 20 to the outlet duct 30 through the two chambers of the enclosure 1. In this case, it is equipped with a blowing device comprising said fan, an electronic control module, two temperature probes (for example, thermistors), and a user interface. Power is supplied either by an adapter converting the 220 V mains current to 12 V-1 A in accordance with CE standards; or by means of a self-contained 12 V-20 W photovoltaic panel, also in accordance with CE standards. One of the temperature probes is housed in a separate plastic casing with a battery power supply, while the other is placed in the enclosure and powered directly by the electronic module.

[0081] The electronic module includes a microcontroller which is subject to a voltage supervisor which starts the microcontroller as soon as the supply voltage also operating the fan exceeds 3.08 V. The microcontroller powers the fan motor only if the voltage is within its operating range (manufacturer's tolerance).

[0082] EXAMPLE 3: Integrated ventilation device

[0083] In an original embodiment of the aerothermal solar panel, the fan, the electronic module, and the temperature probes are integrated into a blowing device. This device takes the form of a housing 50 associated with the outlet duct 30, in which are located the fan, the two thermistors if installed on the facade or via a cable if installed in the attic, and the electronic module. The electronic component, 1.6 mm thick, is screwed into the housing. This housing is installed directly into the 30 mm air outlet duct, in the same way as the exhaust vent of a mechanical ventilation system. This makes it easily accessible and removable, allowing for quick and easy maintenance of the fan, temperature sensors, and electronics.

[0084] The fan chosen here has a power rating of 8 W, capable of generating an airflow of 222 m³ / h. The ventilation is managed according to the mode selected by the user via an interface, accessible from a remote control or from an internet browser.

[0085] EXAMPLE 4: Operation of the aerothermal solar panel

[0086] The panel described above is installed on a facade or roof, oriented as much as possible towards the south, avoiding shadows that could reduce its performance. The sun heats the surface of the glazing, which is in contact with the air inside the panel. As soon as the air temperature inside the panel is higher than that of the building, the ventilation system activates. Even when the outside temperature is cold, heating occurs under the glass as soon as it is exposed to the sun's infrared radiation. The many cold but sunny days will provide heat through aerothermal energy, and therefore a free and renewable energy source. Energy costs (electricity, gas, heating oil, wood, etc.) are reduced accordingly. In summer, the panel helps cool the premises through nighttime over-ventilation.

[0087] The fan is driven at a variable speed by the motor integrated into the device. It is sized here to move an air volume ranging from 30 m³ / h at minimum speed to 160 m³ / h at maximum speed. The fan speed is regulated according to the difference between the indoor temperature of the building to be heated or ventilated and the temperature inside the enclosure, measured by sensors, according to the equation: V = (Tp - Ti) x G

[0088] in which - V represents the fan speed, expressed as a percentage of the motor power to be used. - Tp is the air temperature inside the panel enclosure, in °C, - Ti is the air temperature inside the room, in °C, and - G is a parameter called gain, predefined by the manufacturer after a series of experimental tests, which results from a compromise between noise, efficiency optimization and ventilation speed.

[0089] Two main operating modes have thus been defined, one corresponding to a situation where heating is desired, the other where ventilation is preferred. On Based on this, the electronic module has been configured to offer a winter mode and a summer mode, according to the following modalities, given as an example.

[0090] - In winter mode, the ventilation starts as soon as the temperature of the panel Tp is reached The temperature difference is 3°C above the room's internal temperature Ti. Ventilation stops if the difference is no more than 1°C. The gain has been set at 100. Maximum airflow is reached when the temperature difference is 30°C.

[0091] - In summer mode, the ventilation starts when the panel temperature Tp is in The temperature difference is 3°C below the internal temperature Ti. Ventilation stops if the difference is no more than 1°C. The gain is set at 200. Maximum flow rate is reached when the temperature difference is 15°C.

[0092] Other options can be used, for example a silent mode in which the fan speed is limited; a fast mode in which the fan reaches its maximum speed in 60 seconds; a passive mode, in which the fan is stopped regardless of the temperatures recorded.

[0093] The system is thus completely autonomous and can heat a room even when unoccupied. In particular, a second home will be maintained at a comfortable temperature and well-ventilated even when its occupants are away. In colder areas, for example in mountain villages, the room will be protected from winter frost, which is often fatal to equipment and pipes.

[0094] EXAMPLE 5: Thermal performance

[0095] Tests carried out with a 2 m2 panel, as described in the previous examples, have shown very satisfactory performance.

[0096] For example, during a period of autumn sunshine, the temperature Ti in the room was 24°C in the morning. As soon as the temperature Tp in the enclosure reached 27°C, the fan started. It operated from 10:30 a.m. to 4:00 p.m. at an average speed, supplying 120 m³ / h. The temperature Tp quickly rose to 46°C, bringing air into the room at a temperature 22°C warmer than the ambient air. With an average solar irradiance of 600 W / m² over 6 hours, the panel provided 4.95 kWh.

Claims

Claims

1. Flat aerothermal solar panel provided with means for fixing to a building to be heated, comprising a rigid frame (100) arranged on the periphery of said panel and surrounding an enclosure (1) successively comprising, from front to rear and at a distance from each other, the parts consisting of: - a window (2) made of a material transparent to light forming a front wall, - a heat absorber (3) formed of a metal sheet, - an insulating layer (4) forming a rear wall, the panel being characterized in that the enclosure (1) is provided with side walls formed by partitions (5) rising from the periphery of the insulating layer (4) with which they are integral, said partitions (5) comprising means for holding the transparent window (2) and the absorber (3), and said insulating layer and said partitions being made of at least one insulating material of plant origin.

2. Solar panel according to claim 1, characterized in that said at least one insulating material of said insulating layer (4) and of said partitions (5) is chosen from natural cork, expanded cork, or an assembly thereof.

3. Solar panel according to claim 1 or 2, characterized in that the insulating layer (4) comprises a rigid support plate (6) against which a layer (7) of said insulating material rests.

4. Solar panel according to the preceding claim, characterized in that the insulating layer (4) further comprises at least one reinforcing slat placed between the plate (6) and said layer (7) of insulating material.

5. Solar panel according to one of the preceding claims, characterized in that the partitions (5) are formed of four cleats (51) of rectangular section associated by their ends, each having a first small side (52) placed in abutment against said insulating layer (4), at the edge thereof, and a second small side (53) associated in a jointed manner with the transparent window (2).

6. Solar panel according to one of the preceding claims, characterized in that the partitions (5) comprise means for holding the transparent glass (2) at a predetermined fixed distance from the insulating layer (4).

7. Solar panel according to the preceding claim, characterized in that the second small side of the partitions (5) has a recess (8) made continuously along their inner edge, said recess receiving as support a perimeter area (21) of the transparent window (2).

8. Solar panel according to one of the preceding claims, characterized in that the partitions (5) comprise means for holding the absorber (3) at a predetermined fixed distance from the insulating layer (4).

9. Solar panel according to the preceding claim, characterized in that the partitions (5) comprise a continuous groove (54) parallel to the general plane of the panel, in which a perimeter area (33) of said absorber (3) is inserted.

10. Solar panel according to any one of the preceding claims, characterized in that the rigid frame (100) surrounding the enclosure (1) comprises front and rear extensions (101, 102) forming jaws which respectively overhang the margin of the front and rear walls of the enclosure (1), the parts of said enclosure being held together by the pressure exerted by said jaws.

11. Solar panel according to the preceding claim, characterized in that the frame (100) is a metal or wooden profile formed i) of a chassis (110) laterally surrounding the enclosure (1) and comprising said rear extension (102), and ii) of a glazing bead (120) fixed in said profile and comprising said front extension (101), each of said front and rear extensions being provided with a curved return to bear on said front or rear wall, respectively.

12. Solar panel according to any one of the preceding claims, characterized in that it comprises means allowing the circulation of air through the panel, from the external environment to the interior of the building, comprising: - an air inlet orifice (20) made in the lower lateral part of the panel through the frame (100) and the adjacent partition (5) of the enclosure (1), opening into the space located between the insulating layer (4) and the absorber (3), and constituting a circulation chamber (21), and - an air outlet duct (30) installed in an outlet orifice (31) made in the upper part of the rear wall, leading to the interior of the building.

13. Solar panel according to the preceding claim, characterized in that the air inlet orifice (20) is made opening further partly into the space located between the transparent window (2) and the absorber (3) constituting a collection chamber (22).

14. Solar panel according to any one of claims 1 to 11, characterized in that it comprises means allowing the circulation of air through the panel, from the external environment to the interior of the building, comprising: - an air inlet orifice (20') made in the lower part of the rear wall of the enclosure (1) through the insulating layer (4), opening into said circulation chamber (21), and - an air outlet duct (30) installed in an outlet orifice (31) made in the upper part of the rear wall, leading to the interior of the building.

15. Solar panel according to the preceding claim, characterized in that the absorber (3) comprises at least one perforation (32') in its lower part, allowing air to circulate from the circulation chamber (21) to the collection chamber (22).

16. Solar panel according to one of claims 13 or 15, characterized in that the absorber (3) comprises at least one perforation (32) in its upper part, allowing air to circulate from the collection chamber (22) to the circulation chamber (21) with a flow rate proportional to the number of perforations (32) and to their size.

17. Solar panel according to any one of the preceding claims, characterized in that it further comprises: - a fan capable of driving air from the inlet orifice (20) to the outlet duct (30) through the enclosure (1), - optionally means for supplying electricity to said fan, - an electronic management and control module, - a user interface.

18. Solar panel according to the preceding claim, characterized in that it further comprises two temperature probes configured to periodically record the temperature prevailing respectively in the enclosure (1) of the panel and in the equipped building, the electronic module being configured to receive and compare the temperature data provided by said probes, and - if the temperature in the enclosure is higher than that of the building by a predetermined setpoint value, operate the fan to blow hot air, - if the temperature in the enclosure is lower than that of the building by a predetermined setpoint value, operate the fan to blow fresh air.

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