Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
  • H02S20/00—Supporting structures for PV modules
  • H02S20/20—Supporting structures directly fixed to an immovable object
  • H02S20/22—Supporting structures directly fixed to an immovable object specially adapted for buildings
  • H02S20/23—Supporting structures directly fixed to an immovable object specially adapted for buildings specially adapted for roof structures
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B10/00—Integration of renewable energy sources in buildings
  • Y02B10/10—Photovoltaic [PV]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy

Definitions

• the present invention relates to a system for manufacturing photovoltaic panels and the special modular panels used in its production and composition.
• the system uses a new photovoltaic panel conformation, which can be combined in all possible insolation situations that may be obtained over the course of the solar year, in order to make better use of the surfaces available for their application, that is, south facing surfaces on the roofs of buildings, with the aim of maximising the effect of light capture and system yield, also in the presence of obstacles to the said insolation.
• the prior art already includes photovoltaic panels with cells arranged in rows and columns in order to cover the available surface of the panel itself.
• the panels are composed with the arrangement of the cells, which have an approximately square conformation, with either bevelled or non-bevelled corners, that is, cells in silicon "monocrystal” or “polycrystal", both with sides measuring either 125 or 155 mm.
• Standard photovoltaic panels are composed of cells connected together in series, in order to use cells arranged in rows or columns and obtain the shorter side and a longer side of the rectangular panel, the shorter measurements being obtained by using cells with sides measuring 125 mm.
• the prior art also includes triangular or trapezoid-shaped modules with a lower number of cells than the rectangular modules, to be combined on the available surface and advantageously better exposed to sunlight.
• the panels with photovoltaic cells are usually arranged on the roofs of buildings so as to obtain the strongest and most constant levels of illumination. Therefore, when the panels are being arranged on the roofs of buildings, they are placed in the most advantageous position and orientation so as to maximise the light captured over the entire year, as during the winter months even just light is sufficient to trigger the photovoltaic generation of free electrons. These are driven by opposite sides of the silicon in the cell, which acts as a barrier. The flow of free electrons in the electric connections between the cells and the inverter generates electrical energy.
• Another aim in the arrangement of photovoltaic panels is to take advantage of the available surface with the highest number of panels, in order to maximise the power that can be obtained from the system, even if the building has limited roof dimensions.
• This method therefore respects the architectural silhouette of the building and means that the panels can be firmly fixed and be at the same height as the roof and tiles and be matched alongside them.
• the document JP 2001 073522 included in the prior art describes a roof of a building that was built especially to house the photovoltaic panels and maximise the roof covering. It describes the formula for the sizes and numbers of panels, starting from the roof measurements and the inclination of the slope. In the text, various panel types are described: rectangular ones with 20 to 30 cells and also triangular ones with 10 cells and trapezoidal ones with 20 cells.
• the plan for constructing the system, which is then created based on this, is characterised by a considerable number of also small panels, so as to completely cover the roof pitches, as a result creating a very high number of electrical connections between the panels, as can be seen in the numerous examples.
• a high number of connections is extremely advantageous to the duration of the system as the electrical junctions in the wires between the panels are subject to breakage over time due to the variability of oxidation in the contacts with increase in resistance, thus greatly reducing the reliability of the system; given the solely geometric arrangement for installing the system on the roof, the technical problem of connecting the panels to obtain balanced strings and avoiding the occurrence of "mismatching" between strings connected in parallel remains to be solved.
• the document illustrates various examples for the application of connections in parallel between strings and the solution to the complex problem of organising the system of photovoltaic panels with good covering of the available surface and a good yield for the assembled panels. It is resolved by using a group of rectangular panels with sides that have very different measurements, so as to be of equal width, but with different lengths by at least two measures.
• the text shows examples of coverings, with calculations of percentages obtained, and examples of electrical connections to limit "mismatching" between strings. It also deals with the functioning problems of the system, but this is limited to the connection with the inverter and its activation on reaching the minimum voltage.
• the document does not solve the problem of limiting and simplifying the electrical connections, given the high number of panels used.
• the working voltage is 0.5 V, independently of the size (side measuring 125 mm or 155 mm) of the cell.
• Other parameters like power, duration and internal resistance do not affect the voltage, as this is an electrochemical effect of the excitation of the silicon layer due to the light photons crossing it, whereas the internal resistance of a panel affects the current that crosses it.
• the best system solution is to install identical modules, that is, with cells manufactured in the same batch, so as to guarantee electrical compatibility between the panels and minimise loss due to current crossing in the string of panels/cells.
• parallel coupling of strings of panels/cells that are not perfectly identical causes "mismatching" due to the different voltage/current yield of the strings.
• the necessity to achieve the maximum performance that can be obtained with the available roof surface requires the photovoltaic panels to be of opportune shape and size to take advantage of the roof surface in the best possible way.
• the triangular-shaped panel with 21 photovoltaic cells arranged in series which is then combined with rectangular panels with 42 cells made by Sharp, has to be manufactured with a right and left-hand conformation, as the lengths of the sides are different, in order to be coupled with the rectangular panel on just one side.
• the invention solves the above-mentioned technical problem, by using a system of photovoltaic panels with rectangular and triangular bases in combination with each other to form the surface for capturing solar radiation, comprising rectangular and triangular panels in which the number of cells near the hypotenuse is equal to the number of cells near each side and rectangular panels with a number of cells on the shorter side equal to the number of cells present on the side with the triangular panels and a number of cells on the longer side equal to the number of cells present on the shorter side, plus one, characterised by the fact that the sides of the triangle are equal, that is, the triangular panel has a right-angled triangular shape, and the vertexes of each side and the hypotenuse are cut with short sides, which are also equal to each other, near the cell on the end of the row and with a right-angled direction with respect to the side (L); the photovoltaic cells in the rectangular and triangular panels, used for the same system, with the same electrical efficiency characteristics as each other and at least in the production batch and
• the triangular panel can be installed on the left or right side of the rectangular panel, without distinction, and the triangular panel in the system is used aligned or slightly staggered with respect to the rectangular panel alongside it.
• a specific embodiment of the invention involves the use of photovoltaic cells with sides that measure 125mm; these may be of the type obtained using silicon monocrystal or polycrystal.
• the rectangular panel has eight cells on the shorter side and nine cells on the longer side and the triangular panel has eight cells on each side.
• the combination of rectangular and triangular panels is carried out indifferently in the same string for the power supply of the inverter for electrical current transformation from direct current to alternating current.
• the combination of rectangular and triangular panels of the invention has the triangular panels arranged, with regard to laying the panels on a roof in general, in a certain way so as to avoid obstacles to sunlight illumination and avoid shading of the said panels.
• the combination of rectangular and triangular panels has panels arranged, with regard to laying the panels on a roof in general, on at least two strings to avoid constructions that may shade the said panels from sunlight illumination, even for just a few days in the winter months, or to enable precise subdivision into identical numbers of panels in the strings.
• Figure 1 is a schematic plan view of a triangular-shaped photovoltaic panel with 36 cells, in accordance with the invention
• Figure 2 is a schematic plan view of a rectangular-shaped photovoltaic panel, with 72 cells, which can be combined when assembling systems with the photovoltaic panel in Figure 1
• Figure 3 is a schematic plan view of the arrangement of photovoltaic panels in Figures 1 and 2, in accordance with the invention
• Figure 4 is a schematic view similar to Figure 3 in which the rectangular photovoltaic panels have been rotated by 90 degrees, so as to make the best use of the actual roof surface on which the system has been installed
• Figures 5 and 6 show a schematic view of a construction that may shade the panels alongside a panel system, in the two views from right and left with respect to the southerly direction S shown by the arrow: the shade is calculated for the early morning in the month of December when there is the minimum level of insolation, in accordance with the invention
• Figure 1 shows the triangular panel in accordance with the present invention, which has two sides L of identical length, as they comprise eight photovoltaic cells 2, laid alongside each other, of the monocrystal square type with bevelled vertexes and sides measuring 125 mm.
• the total number of cells is thirty-six as the cells of the hypotenuse 3 are all included in the group of cells used for the triangular panel 1 , the sides of the panel measure 1070 mm (+/-5 mm), the shorter sides M, positioned to cut the vertexes, measure 155 mm (+/-5 mm).
• Figure 2 also shows a panel 4 with photovoltaic cells 2, alongside each other, of the monocrystal square type with bevelled vertexes and sides measuring 125 mm, arranged to form a rectangle with sides of similar lengths.
• the side of the panel RC which is shorter, is located on the side where there are eight cells 2, while on the side next to this, which is a bit longer RL, there are nine cells 2.
• the cells are identical to those used in the triangular panel 1.
• the total number of cells is seventy-two and the sides of the panel measured 1070 mm (+/-5 mm) for the shorter one RC, and 1200 mm (+/-5 mm) for the longer one RL.
• Figure 3 shows the arrangement of the photovoltaic panels in plan view of a roof pitch F of a roof on which the system has been installed.
• the rectangular photovoltaic panels 4 have been rotated by 90 degrees, with respect to the arrangement in Figure 3, so that the surface covered by the roof pitch F is identical, whereas the conformation of the system has a distance D for matching with the ridge P of the most constant roof pitch.
• the possibility of combining the rectangular photovoltaic panels 4, whether they are rotated or not rotated, enables the actual conformation of the surface covered to be adapted to the variable, among different roofs, of the convergence, which may be more or less accentuated, of the ridge P lines.
• the triangular panel 1 due to its shape with vertexes cut in the shorter sides M, enables it to be oriented in the most convenient way to cover the surface that can be used, also taking into consideration the obstacles between the sunlight and the panel.
• the combination of the rectangular and triangular panels in the arrangements shown in Figures 1 and 2 enables the number of articles held in the warehouse to be reduced, as the panels must be subdivided depending on the electrical characteristics of the cells used, so panels with different resistance characteristics cannot be used together in the same string, or adjacent strings.
• Panels that are structurally the same but with different electrical characteristics must be used separately in different systems; for this reason the management of panels between manufacture and installation must be carried out in such a way to avoid large stocks of panels being created, as they cannot be used together with others, in order to reduce the level of capital wasted on the cost of panels that will no longer be used or are difficult to use in other systems.
• the application of the photovoltaic panel system is versatile and can be adapted to the actual conformation of the roof on which it is to be installed.
• there are adaptations of the panel system that may be made in the presence of shading obstacles which, as mentioned previously, would make the system or one of its strings ineffective, even if only a small part of a single panel was shaded; in the following Figures the southerly direction is indicated by the letter S and the shadows are calculated for the latitude of Italy.
• the arrangement of the rectangular panels 4 and the triangular panels 1 enables the shading OS of the adjoining wall structure MC on the roof pitch F to be avoided.
• Figures 21 to 25 show a system with rectangular 4 and triangular 1 photovoltaic panels on the roof of a building with several sloping roof pitches 5, 6, 7 and 8, some of which face south-east, 5 and 7, and some south-west, 6 and 8; a chimney C is present on the roof pitch 5 facing south-east, so it is necessary to limit the photovoltaic panels on the main roof pitch 5, to avoid shading from the said chimney, shadows C1-C5, and as a result, there is a reduction in the efficiency of the system.
• the shading, shadow C1 is calculated for the month of February, in the winter, in the morning: the triangular 51 and rectangular 54 panels present on roof pitches 5 and 7 are illuminated and can generate the voltage necessary for triggering the inverter (not shown), while the triangular 61 and rectangular 64 panels on roof pitches 6 and 8 are not illuminated and must be designed on a different string in order to enable them to be excluded and avoid "mismatching" between the strings; the system, even if at reduced power, can work with maximum efficiency by avoiding unwanted shade and making sure to use two separate inverters or one inverter of the type with the connection of two separate string inputs, that is, "multi-string-control".
• the strings are connected to a circuit-breaker relay in direct current RB before the inverter and below it another circuit-breaker relay in alternating current RA connects the system to the electricity network NE by means of the meter MS.
• the system shown in Figure 26, where the panels are arranged to cover the roof pitch F of the roof, makes the best use of the geometrical versatility of the triangular panels in the invention; while in the system shown in Figure 28 the use of triangular panels 1 serves to avoid the shadow CO and the presence of the said chimney C.
• Figures 30, 31 and 32 show a system for an industrial warehouse, which would normally create problems in terms of subdividing the rectangular panels 4 into strings, which must be of a sufficient number to cover the surface of the roof pitch F; in the example there are seventeen rectangular panels and one triangular one for each of the six strings.
• the system shown enables the dimensions of the strings to be determined with double the number of possible combinations with respect to the use of single modules; in this case the triangular modules 1 are placed opposite each other so as to be complementary and form a rectangle with measurements that are adapted to the rectangular modules, and also from the "electrical" point of view, where the triangles represent the separation terminals between two different strings.
• the system of photovoltaic panels comprising at least one triangular panel 1 enables a combination of the panels in a simple way and in series with the rectangular panels 4, for the electrical connection of panels with each other, so as to permit the same type of electrical connection.
• the conformation of the triangular panel is only slightly bigger than the exact conformation of half of the surface of the corresponding rectangular panel: in fact, the arrangement of the cells with 8 rows and 9 columns, or vice-versa, only slightly changes the orientation and positioning of the roof surface occupied; therefore, given the possibility of carrying out the electrical connections appropriately, the rectangular panel can be rotated or not rotated with respect to the side L of a triangular panel alongside it, so as to only slightly change the measurements of the surface covered on the roof and better adapt the position of the vertexes of the panels near the ridge of a roof between the adjoining hips.
• the triangular panel with cut vertexes is equilateral, with equal sides L, and has shorter sides M, which are also equal, to limit overhang near the ridge line of the roof pitch.
• the combination of the photovoltaic panels enables high voltage levels to be obtained, to provide optimal power supply conditions for the inverter, even with one or few strings; the limited number of panels provides for guaranteed and reliable functioning over time, as the electrical junctions, which may be a source of future breakages, are reduced in number.
• the versatility in assembly to cover the areas of the roof allows for the avoidance of shading by obstacles also on winter days when the sunlight incidence is at its minimum value.
• the last but not least advantage is the economic one, which is evident, in that the set of rectangular and triangular panels described enables the costs of production and technical conformity to fixed standards (certification) to be minimised, as well as those of warehouse management, where the electrical characteristics among the batches of cells used in the construction of panels are varied, which in theory, but not in practice, are identical, and also the management of warehouse stocks, that is, panels that have not been installed due to excess production with regard to the number required for a system.
• the panel system in accordance with the invention, enables the use of all the available space on the covering; at the same time it enables all the photovoltaic panels to be divided into strings that are identical to each other and strings with the highest working voltage possible to be created, without exceeding the no-load voltage limit values (typically 20% - 25% higher than the nominal voltage) of the inverter; for large systems, where inverters with voltages on the direct current side to the order of 800 VDC are used, it is possible to use modules with half the power, like the triangular modules 1 , limiting the management of the energy produced to a single inverter, thus making the system much less expensive.
• no-load voltage limit values typically 20% - 25% higher than the nominal voltage

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Photovoltaic Devices (AREA)

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• 2009
  • 2009-05-14 WO PCT/IB2009/005603 patent/WO2009138868A2/en not_active Ceased
  • 2009-05-14 EP EP09746163A patent/EP2291863A2/en not_active Withdrawn
• 2010
  • 2010-12-13 SM SM201000123T patent/SMP201000123B/it unknown

Non-Patent Citations (1)

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