FR3033628A1 - DEVICE FOR PRODUCING SOLAR ENERGY OPTIMIZED ACCORDING TO SEASONS - Google Patents

Abstract

The transparency of a surface comprising a multitude of solar panels (1a, 1b, 1c, 1x) decreases when the height of the sun (11) increases and on the contrary this transparency increases when the height (11) of the sun decreases. This solar shade is characterized in that on the one hand glass plates (2a, 2b, 2c, 2x) are juxtaposed with solar panels (1a, 1b, 1c, 1x) so as to filter more or less solar radiation in function of the angles of incidence on said glass plates (2a, 2b, 2c, 2x) and on the other hand a part of the solar radiation reflected on said glass plate (2a, 2b, 2c, 2x) accumulates on the surface of said solar panels (1a, 1b, 1c, 1x). The device is particularly interesting when it covers a greenhouse (Figure 5) or a building facade

Description

The present invention relates to thermal and / or photovoltaic solar panels which are separated by transparency spaces and which are arranged relative to one another so as to optimize the production of calories and / or electricity and to control the solar radiation that passes through them. STATE OF THE ART The solar panels can be positioned in height in order to create below a space that can either never receive direct solar radiation or receive only a part of the solar radiation, this transparency to solar radiation is then function the spacing between the panels, their orientation and the height of the sun. Special arrangements of solar panels are already known which allow more light to be passed in the winter than in summer, in order to regulate the lighting and / or the temperature inside buildings and agricultural greenhouses. However, it should be noted that in order to fulfill this property of regulating light as a function of the height of the sun, it is necessary to orient the panels in a non-optimal manner for their heat or electric production, and also sometimes to accept that the panels shade each other at certain times of the day and for certain seasons, which decreases the performance of said solar panels. OBJECT OF THE INVENTION The object of the invention is to describe a device comprising solar panels, said device having a percentage of transparency to solar radiation which is inversely proportional to the height of the sun and whose calorific and / or electrical production is improved by an accumulation of solar radiation on the surface of said panels.

Subsequently, the terms "transparency" and "reflection" are understood as a transparency and a "visual" reflection, that is to say which mainly concerns the visible light of the solar spectrum. SUMMARY OF THE INVENTION . The invention relates to a modular device, each module 5 comprises at least one solar panel arranged substantially horizontally and at least one transparent glass plate, characterized in that: (i) each glass plate is arranged in the right of a solar panel and in elevation relative to it and has a south facing face if the device is located in the northern hemisphere or a face 10 facing north if the device is located in the southern hemisphere, and (ii) the axis (N) perpendicular to said oriented face is inclined by an angle (A) of less than 440 under the sun's position when it passes to the meridian of the location at the lower of its seasonal trajectory, and (iii) each solar panel and each glass plate is sized and arranged so that a portion of the incident solar radiation passes through said glass plate and another portion of the solar radiation is reflected by said plate of glass towards said solar panel, so that each solar panel 20 receives both the direct radiation of the sun and the radiation reflected by a glass plate. Several unitary devices of this type can advantageously be juxtaposed, and separated by gaps of transparency, to form a shelter, especially for a greenhouse. The solar panels of the different devices are then aligned to form a substantially flat and horizontal surface. Advantageously, the relative position of the devices is adjustable and in that the distance between two devices is adjustable, which allows to obtain shades whose degree of transparency is adjustable depending on the needs, especially in relation to greenhouse crops.

The structure and arrangement of the devices have the effect that depending on the incidence angles of the solar radiation, the reflection coefficient of the transparent glass plates will increase gradually during the year at the same time as will increase the height of the sun during its passage to the meridian of the place, which will firstly gradually increase the accumulation of light on the surface of the solar panels by reflection on said glass plates, and on the other hand gradually reduce the transparency said device. Conversely, the reflection coefficient of transparent glass plates will gradually decrease during the year while reducing the height of the sun during its passage to the meridian of the place, which will firstly gradually decrease the accumulation of light on the surface of the solar panels by reflection on said glass plate, and on the other hand progressively increase the transparency of said device. Each glass plate is made of mineral glass or organic glass, both sides are polished which allows for a significant direct reflection of the light at high angles of incidence, and a high transparency at low angles of incidence relative to the perpendicular (the normal) to the plate. The juxtaposition of said glass plate with a solar panel makes it possible to redirect at least part of the light received by the plate towards the active surface of said panel and thus to produce an accumulation of solar light which increases the electrical production performance. The amount of light reflected by the glass plate to the panel and also the transparency of the device are a function of the angle of incidence of solar rays which varies with the height of the sun. The average height of the sun compared to the horizon depends mainly on the seasons, which means that the glass plate will be more or less transparent and reflective depending on the season. So that the transparency is more important in the winter when the sun is low and the transparency is lower in the summer when the sun is high, it is necessary to orient the glass plate so that the angles of incidence gradually increase between the position of the lowest sun and its highest position. When the glass plate is oriented to the south in the northern hemisphere, (and the opposite in the northern hemisphere) the angular difference between the lowest and the highest position of the sun at its meridian passage is 46 °; the position 303 362 8 4 lower than the horizon is 900 - the latitude of the place. The optimal orientation of the normal to the glass plate is therefore the lowest position of the sun or a position which is lower without this position causing the solar radiation to exceed beyond an axis parallel to the surface of the sun. 5 glass plate when the sun is in its highest position. This constraint is respected when the normal to the glass plate does not fall more than 90 ° - 46 ° = 44 ° below the lowest position of the sun. This limit position, depending on the geographical location, may be above or below the horizon. The solar panels are positioned with respect to the glass plates in order firstly to receive the maximum of direct radiation from the sun and secondly to receive a maximum of light reflected from the glass plate. The solar panels are positioned relative to each other by leaving a space of transparency between them so that the device passes the amount of sunlight calculated for the type of application chosen. For example, for a simple seasonal shading effect, the overall area of the solar panels may represent 50% of the total area of the device. For an agricultural application that requires a lot more light, the overall surface of the solar panels can represent only between 20% and 30% of the total surface. The reduction of the active area of the solar panels is then partially compensated by an effect of solar radiation accumulation by reflection on the glass plates which brings a surplus of heat production or annual electricity of about 15%. In a particular embodiment of the invention, the solar panels are aligned to form a substantially flat and horizontal surface. Advantageously, the relative position of the unitary devices is adjustable and the distance between two devices is adjustable, which makes it possible to adjust the degree of transparency of the assembly. In another particular embodiment, the solar panels are aligned to form a substantially flat and vertical surface. In another particular embodiment, the solar panels are semi-transparent, this semi-transparency being able to result either from a juxtaposition of opaque photovoltaic zones separated by zones of total transparency or from intrinsically semi-transparent photovoltaic surfaces such as for example deposits of amorphous silicon of very small thicknesses. In a particular embodiment, said device is positioned above and / or in front of a greenhouse to form an ornament. In comparison with existing photovoltaic devices which alternate only opaque solar panels with transparency spaces, this particular embodiment has the advantage of producing less significant total shading areas under the greenhouse, since the attenuation of the Solar light is done in part by the semi-transparency of the glass plates. It is known that some plants do not withstand the effects of total shading and it is preferable to generate in the greenhouse a diffused light. In a particular embodiment of the invention, the solar panels and the glass plates are aligned in height in a "staircase" arrangement, so that at least a portion of the solar radiation which is reflected on the multitude of glass plates is moving towards a single solar panel thus causing a solar concentration effect on said single solar panel. This solar concentration makes it possible to multiply the heat or electrical production of said single solar panel and thus to reduce the cost of the energy produced. This "staircase" alignment is particularly interesting when it comes to building facades and the glass plates are the windows used for the windows. In another particular embodiment, the glass plates are treated so as to reflect largely the ultraviolet radiation and / or infra-red radiation, which does not detract from the visual transparency of the glass plates 25 but also increases the production efficiency of solar panels. DETAILED DESCRIPTION OF THE INVENTION The invention is now described in more detail with the aid of the description of the indexed FIGS. 1 to 6.

Fig. 1 is a graph which shows the variation of the transmission and reflection coefficient of solar radiation on the surface of a glass plate as a function of the angle of incidence of the radiation on the glass plate.

FIG. 2 is a schematic block diagram of a glass plate showing the effects of reflection and transmission of solar radiation on the glass plate according to FIG. 1; Figure 3 is a cross-sectional block diagram of the device according to the invention; Figure 4 is a sectional view of a particular embodiment in which the glass plates and solar panels are arranged in "staircase". Figure 5 is a three-dimensional view of an embodiment in which the device is positioned as a shade on a greenhouse.

Figure 6 is a three-dimensional view of an exemplary embodiment in which the device is positioned in "staircase" and in front of a building. The diagram of FIG. 1 shows in section the transmission (T), the reflection (R) and the absorption (S) of a light ray which illuminates a glass plate (2). The corresponding graph changes the abscissa angle of incidence of said light beam relative to the normal (N) to said glass plate (2); this angle of incidence may vary from 00 to 90 ° .In ordinate, the corresponding percentage of transmission (T) and reflection (R) of the said light beam is observed. It is noted that the reflection coefficient (R) grows very rapidly from an incidence greater than 60 °. The diagram shows an example in which an incidence of 30 ° causes a 90% transmission, a reflection of 8% and an absorption (S) in the glass (2) of 2%. FIG. 2 shows the position (3) of the sun in the south during its passage at the meridian at the time of the summer solstice and its position (4) at the time of the winter solstice (4). The height of the sun varies between these positions with an angular amplitude (11) which is 46 °. The lowest position is 90 ° - the latitude of the place - 23 ° and the highest position is the latitude place 90 ° - the latitude of the place + 23 °. A transparent, smooth glass plate (2) faces south if the device is located in the northern hemisphere (and vice versa if the device is located in the southern hemisphere). The axis (N) which is perpendicular to said glass plate (2) is oriented at the lowest position of the sun (4) and forms an angle "A" with said lowest position of the sun (4). Said angle "A" is between 0 ° and 440.

This angular characteristic makes it possible to have angles of incidence (from A to B) of the solar radiation (8.5) on the glass plate (2) which are gradually increasing as the height (11) increases. the sun increases, and without the maximum angle "B" (which is A + 46 °) does not exceed 900. Thus it can be seen that the higher the height of the sun and the higher the percentage of reflection on the plate. glass (2) is important and conversely for the percentage of transmission. The lowest solar rays (8) pass further through (9) the glass plate (2) while the uppermost sun rays (5) pass through (6) the glass plate (2) less. In all cases, the reflected rays (10, 7) orient towards the surface of a solar panel (1) which is juxtaposed with said plate (2). Said solar panel (1) therefore receives both the direct radiation of the sun and the radiation reflected by said glass plate (2) which increases its annual average electricity production. The device allows on the one hand to let more light (9) pass when the sun is low (4), that is to say when in its position 15 the least bright, and on the other hand to let spend less light (6) when the sun is high (3), that is to say when the sun is in its brightest position. The glass plate (2) globally regulates the brightness of the space behind or under it (2) while allowing the photovoltaic panel (1) to produce more electricity than if said glass plate (2) was absent.

Fig. 3 shows the device which comprises a plurality of solar panels (1a, 1b, 1c ... 1x) which are separated by gaps of transparency, and which also comprises a plurality of transparent glass plates (2a, 2b, 2c ... 2x) which are juxtaposed with said solar panels (1a, lb, lc ... 1x). Said glass plates (2a, ..., 2x) are oriented according to the characteristics of the description of the preceding FIG. 2 so that during the gradual movement of the sun (11) during the seasons and during the day, the radii solar cells from the lowest positions of the sun (8) will cross (9) more said glass plates (2a, .. 2x) than the sun rays (6) from the highest positions of the sun (5). FIG. 4 shows a particular embodiment in which the glass plates 30 and the solar panels (21a, 21b, 21c, 21x) are positioned in "staircase" so that the solar radiation (8a, 8b, 8c, 8x) which is reflected on said glass plates partially reaches (5a, 9a, 7a) said solar panels 3033628 and concentrates in part (10a, 10b, 10c, .. 10x) on a single solar panel (1x) whose size is preferably calculated so that it receives said reflected radiation regardless of the position (11) of the sun (4,3) during its seasonal movement. The advantage of this embodiment lies in the surface saving of the solar collectors since at least one solar panel receives an accumulation of solar radiation. Figure 5 shows a concrete example of embodiment. An agricultural greenhouse (G) located at a latitude of 45 ° North is covered by a semi-transparent and substantially horizontal photovoltaic surface which is composed of 10 strips of photovoltaic solar panels (1a, lb, lc, ... 1x) of 60 cm wide and 25 m long. The solar panel strips (1a, lb, lc, ... 1x) are spaced apart from each other by a distance of 1.20 meters, which corresponds to an average coverage of opaque panels of 33% and overall transparency. 66%. Strips of glass plates (2a, 2b, 2c, .. 2x) 25 m long and 1.60 m high are juxtaposed perpendicular to the solar panel strips (la, lb, lc, ... 1x ). The southern surfaces of said glass plates (2a, 2b, 2c, ..2x) are oriented to the south and the perpendicular N to their surfaces is horizontal (the angle A between said perpendicular N and the lowest position of the sun (4) is 90 ° - 45 ° - 23 ° = 22 ° which is an angle less than 44 °, so even the uppermost position of the sun (3) will form with the perpendicular (N) to the surface of the glass plate an angle less than 90 ° (exactly less than 22 ° + 46 ° = 68 °), so the solar radiation illuminates mainly the south face of the glass plates (2a, 2b, 2c, .. 2x) with a transparency which is less during the warmer months between May and September Greenhouse plantations receive in the summer a direct radiation from the sun which is attenuated by the significant reflectivity of the glass plates (2a, 2b, 2c, ..2x ) and, conversely, during the winter months, and thanks to the reflection of light (3,4) on the glass plates (2a, 2b, 2c, .2x) photovoltaic solar panels strips (1a, lb, lc, ... 1x) produce an electricity surplus of 15% on average over the year, compared to a 30% device without the glass plates. Figure 6 is another concrete example of embodiment. A residential complex comprises at least one facade (F) oriented to the South and 3 floors equipped with 3033628 windows (2a, 2b, 2x) inclined to the ground at an angle of 200. The windowsills are covered with solar panels photovoltaic cells (1a, 1b, 1c) which receive a portion of the direct sunlight (12) and a portion of the reflected radiation (13) from the windows which are surface-treated transparent glass plates (2a, 2b, 2x) by a thin layer that is reflective to Ultra-violet and Infra-Red. The lowest solar panel (1x) has a width greater than the other solar panels (1a, 1b) to receive a portion of the solar radiation (13) which is reflected by the panes (2a, 2b, 2x) of the upper stages, even when the sun's height varies with the seasons. This "staircase" arrangement is particularly interesting from an economic point of view because the solar energy that is reflected by the windows (visible, Ultra Violet and Infra-Red) is not lost but recovered by a solar panel unique (1x) which therefore receives an accumulation of solar radiation (12,13). On the other hand, the windows, because of their inclination and their reflection coefficient which is a function of the angle of incidence of the solar rays, lose all the more their transparency as the sun is high, that is to say to say all the more that it is necessary to reduce the thermal energy that enters the houses. In a particular embodiment, the windows of the windows are vertical and the south facade is slightly inclined to the north while respecting a layout in the form of "staircase". BENEFITS OF THE INVENTION Ultimately the invention responds well to the goals set by allowing a multitude of solar panels juxtaposed to a multitude of glass plates to vary the transparency of the solar radiation device in a proportionally inverse manner to the height of the sun, and to produce an amount of heat energy and / or improved electricity through an accumulation of solar radiation on the surface of said solar panels.

Claims (8)

CLAIMS1 - Device comprising at least one solar panel (1a, 1b, 1c ... 1x) 5 disposed substantially horizontally and at least one transparent glass plate (2a, 2b, 2c, .. 2x), characterized in that (iv) each glass plate (2a, 2b, 2c, .. 2x) is arranged in line with a solar panel (1a, 1b, 1c ... 1x) and in elevation with respect thereto and has a face south-facing if the device is located in the northern hemisphere or a north-facing face if the device is located in the southern hemisphere, and (v) the axis (N) perpendicular to said inclined face is inclined an angle (A) of less than 440 under the position of the sun (4) as it passes to the meridian of the location at the lower of its seasonal trajectory, and (vi) each solar panel and each glass plate is sized and arranged so that a part of the incident solar radiation is reflected by said glass plate towards said panel olaire, so that each solar panel (1) receives both the direct radiation of the sun and the radiation reflected by a glass plate (2). 2 - Device according to claim 1, characterized in that the solar panels (1a, lb, lc, lx) are of thermal type and / or photovoltaic type and the glass plates (2a, 2b, 2c, 2x) are in mineral glass or organic glass. 25 3 - Device according to one of the preceding claims, characterized in that said solar panels (1a, lb, lc, lx) are semi-transparent, this semi transparency may result from a juxtaposition of opaque photovoltaic zones separated by transparent areas total of either intrinsically semi-transparent photovoltaic surfaces such as amorphous silicon deposits of very small thicknesses. 3033628 11 ' 4 - Device according to one of the preceding claims, characterized in that the glass plates (2a, 2b, 2c, 2x) are treated so as to reflect largely ultraviolet radiation and / or infrared radiation. 5 - Umbrella, especially for agricultural greenhouse, characterized in that it uses several devices according to any one of the preceding claims, separated by transparency spaces, the solar panels of the different devices being aligned to form a substantially flat and horizontal surface . 6 - Shade according to claim 5, characterized in that the relative position of the devices is adjustable and in that the distance (d) between two devices is adjustable. 7 - Device according to any one of claims 1 to 4, characterized in that said glass plates (2a, 2b, 2c, 2x) are the windows of a building. 8 - Device according to claim 8, characterized in that said solar panels (1a, 1b, 1x) and said glass plates (2a, 2b, 2x) are aligned stepwise in the direction of the height, so that a at least part of the solar radiation (8a, 8b, 8c, 8x) reflected on the multitude of glass plates (2a, 2b, 2c, 2x) focuses on a single solar panel (1x) .25