Shrouded or ducted horizontal-axis wind turbine and set of shrouded or ducted horizontal-axis wind turbines

Abstract

The invention relates to a ducted wind turbine comprising: a horizontal rotary shaft (1); blades (3) connected by one end to a bushing (2); and an electric generator (4) connected to the horizontal shaft by a gear box (5). In addition, the blades (2) and the bushing (3) are shrouded by a conduit provided with: an inlet section, with an inlet opening (6) that allows the passage of an air current; a central section, with at least two lateral faces (7a, 7b), an upper face (7c) and a lower face (7d); and an outlet section, with an outlet opening (8) arranged at an angle of 0-75º, such that the angle of the direction of the air current in the outlet opening (8) is at 165-90º with respect to that of the air current in the inlet opening (6).

Description

[0001] COVERED OR CASED HORIZONTAL AXIS WIND TURBINE AND GROUP OF COVERED OR CASED HORIZONTAL AXIS WIND TURBINES

[0002] DESCRIPTION

[0003] Technical field

[0004] The present invention belongs to the technical field of renewable energies and more specifically to that of wind energy.

[0005] In fact, a first object of the invention refers to a horizontal-axis wind turbine (also known as a wind generator) surrounded by a duct whose particular shape, among other advantages, allows for greater use of air currents and thus leads to greater energy production.

[0006] The invention also relates to a grouping of wind turbines, in which two or more of the previously defined enclosed wind turbines are arranged downstream of each other, forming at least one row.

[0007] Background

[0008] The use of renewable energy sources, and in particular wind energy, has experienced a clear boom in recent years, not only in Spain, but throughout Europe and most industrialized countries, among other reasons, due to a progressively greater awareness of the environmental risks derived from using non-renewable energy sources, and especially those based on fossil fuels.

[0009] Thus, multiple types of wind turbines have been developed, made of different materials and designed for installation in various locations: on land, offshore, or even on freshwater. These turbines harness the kinetic energy of moving air to rotate the rotor of an electric alternator and generate alternating current. Thanks to successive improvements in wind turbine design, the cost of generating wind energy has gradually decreased, while the adoption of this technology has increased significantly. According to data from the Spanish Wind Energy Association (AEE), in 2023 Spain had more than 22,000 wind turbines installed, generating over 61,000 GWh and 30,000 MW of cumulative power, making it the leading source of electricity generation, covering more than 24% of demand.

[0010] Nevertheless, there is still room for improvement, and in the wind energy sector it would be advantageous to develop new wind turbines capable of making better use of air currents and, therefore, achieving greater efficiency in energy production.

[0011] Furthermore, the noise generated by horizontal-axis wind turbines during their operation causes significant disturbance to the nearby population, which limits the expansion of horizontal-axis wind farms.

[0012] General description of the invention

[0013] To overcome the aforementioned drawbacks, a first object of the present invention relates to a horizontal axis wind turbine comprising:

[0014] -a horizontal rotating axis;

[0015] - a hub rigidly attached to one end of the rotating shaft;

[0016] - blades, each blade being connected at one end to the hub to form a rotor, so that the rotation of the blades caused by the air currents induces a rotation of the rotating shaft;

[0017] -an electric generator connected to the rotating shaft via a gearbox. The horizontal rotating shaft, blades, and hub are at least partially enclosed by a duct. The duct comprises:

[0018] * an inlet section, provided with an inlet opening, the inlet opening being configured to allow the passage of an airflow towards the rotor in a direction perpendicular to said rotor; * a central section, delimited, at least, by two side faces, an upper face and a lower face and configured to allow the passage of the airflow to an outlet section; and

[0019] * an outlet section, provided with at least one outlet opening, the outlet opening being oriented essentially within an angle range of 0°-75°, as shown in the figures. Thus, the direction of the airflow at the outlet opening is within an angle range from 0 degrees to 75 degrees (according to the figures).

[0020] Advantages of the invention

[0021] Thanks to the unique geometry of the duct of the horizontal-axis wind turbine according to the present invention, described above, greater utilization of air currents is possible, resulting in increased energy production, as shown in Table 1. Comparing the energy produced by the ducts of the invention with those of existing horizontal-axis wind turbines reveals a significant improvement in wind energy utilization, both at the level of individual ducts and in the total energy generated from a row of ducts. Furthermore, the ducted wind turbine of the invention can operate under a wide range of weather conditions, including low-speed, moderate-speed, and even high-speed turbulent conditions.

[0022] In fact, under high wind conditions, the duct provided in horizontal-axis wind turbines according to the present invention acts as a self-regulating mechanism. This makes it possible—in some cases—that even if the wind speed outside the wind turbine exceeds the maximum operating speed tolerated by other prior art wind turbines, in the case of a wind turbine according to the present invention, this speed near the rotor remains below the limit, allowing it to continue operating.

[0023] Furthermore, the aerodynamic design of the duct significantly reduces the noise generated by the wind turbines of the invention during operation, compared to other known wind turbines. In addition, thanks to its unique design, the wind turbine duct according to the invention minimizes potential interference with birds and radar waves, increasing its versatility and allowing the wind turbines according to the present invention to be installed in a wider range of locations, including urban areas. The arrangement of the horizontal-axis ducted wind turbines proposed in this invention allows them to function as a micro-compact wind farm, suitable for installation in small and restricted areas. The structure can be manufactured as a modular unit in a factory and transported as a single unit for installation on rooftops or ground in areas designated for wind farm development.Common types of horizontal-axis wind farms require a large installation area due to the wake phenomenon behind the turbines and its negative effects, such as high-intensity turbulent flow and wind speed deficits. Therefore, the invention works to mitigate the wind speed deficit in the wake zone.

[0024] The invention, which utilizes small-sized conduits, will be a suitable solution for supporting the energy systems of buildings, trains, long vehicles, and ships as a source of renewable energy, thus contributing to efforts to reduce dependence on fossil fuels and support the transition to lower CO2 emissions. The proposed design allows for the installation of photovoltaic solar panels on the outer surface of the conduits, making it a potentially attractive hybrid resource for renewable energy.

[0025] Preferably, the wind turbine of the invention is also equipped with at least one solar panel, said solar panel being attached to one of the faces of the central section, to one of the walls of the funnel-shaped region, and / or to one of the portions of the outlet section. This embodiment of the invention is particularly advantageous because it allows the space occupied by the wind turbine tower to be used to generate electricity simultaneously from two different renewable energy sources: wind and photovoltaic solar. Furthermore, it allows for continued electricity generation from the solar panel(s) even when there is no wind, provided, of course, that sufficient solar radiation falls upon them.

[0026] Throughout this description, it should be understood that terms describing spatial orientations, such as “vertical,” “horizontal,” “upper,” “lower,” etc., refer to the case where the wind turbine is in its assembled condition at the installation site. Therefore, a “horizontal” direction is, in principle, parallel to the ground, while a “vertical” direction is perpendicular to the ground. In a preferred embodiment of the invention, compatible with the other possible embodiments thereof, the inlet section of the wind turbine is further provided with a funnel-shaped region comprising at least two side walls, an upper wall, and a lower wall, these walls defining the inlet opening.

[0027] In another preferred embodiment of the invention, compatible with the other embodiments thereof, the outlet section of the wind turbine comprises at least two side portions and a rear portion, the outlet opening being delimited by said side portions and the rear portion of the outlet section, as well as by the lower face of the intermediate section. Furthermore, in this embodiment of the invention, the rear portion of the outlet section may optionally be provided with through-holes.

[0028] In a possible embodiment of the wind turbine of the invention, the duct has the following geometry:

[0029] The central section comprises two side faces, a top face, and a bottom face, each of which is an isosceles trapezoid, and the exit section comprises three faces: two triangular side portions and a rear portion. Each of the two side portions has an upper angle in the range of 0 o at 75°. (See the attached figures to illustrate the proposed angle).

[0030] A second aspect of the invention relates to a grouping of horizontal-axis ducted wind turbines in which two or more of the above-described ducted wind turbines are arranged downstream of each other, forming at least one row, so that the inlet section of the second wind turbine is arranged behind and aligned with the central section of the first wind turbine.

[0031] Preferably, the distance between adjacent wind turbines belonging to the same row is constant. Even more preferably, all wind turbines belonging to the same row have essentially the same rotor diameter, and the distance between adjacent wind turbines is proportional to that rotor diameter.

[0032] In a particularly preferred embodiment of the invention, the distance between adjacent wind turbines in the same row is approximately 1.5 to 2.5 times the rotor diameter. This distance is considerably less than that required in horizontal-axis wind turbine rows of the prior art, which is usually on the order of 5 to 7 times the rotor diameter, due to the wake phenomenon that typically forms behind such wind turbines.

[0033] Brief description of the figures

[0034] The foregoing and other advantages and features of the invention will be more fully understood from the following detailed description of exemplary embodiments with reference to the accompanying drawings, which are to be regarded as illustrative and not limiting, in which:

[0035] Figures 1 and 1a are schematic views of a first wind turbine according to the present invention;

[0036] Figures 2a and 2b schematically illustrate a duct of a second wind turbine according to the present invention, whose inlet section is provided with a funnel-shaped region and whose outlet section is provided with two side portions and a rear portion;

[0037] Figure 3 is a schematic view of a duct of a third wind turbine according to the present invention; wherein the outlet opening is provided with a long rim, or in other words, the lengths of the two lateral and rear portions of the outlet section are longer than in the case of Figure 1. The position of the central section in this particularly preferred embodiment is not at the same level as the inlet section; the central section is still parallel to the inlet section but with a flat top portion of the inlet section.

[0038] Figure 4 is a schematic view of a duct of a fourth wind turbine according to the present invention, wherein the outlet opening is arranged at the top of said duct;

[0039] Figure 5 is a schematic view of a duct of a fifth wind turbine according to the present invention, similar to the wind turbine duct shown in Fig. 1, but provided with holes;

[0040] Figure 6 is a schematic view of a duct of a sixth wind turbine according to the present invention, similar to the duct shown in Fig. 1, but provided with a concentrator or converging body around it; Figure 7 is a schematic view of a duct of a seventh wind turbine according to the present invention, provided with two rear portions; and

[0041] Figure 8 is a schematic view of a row of horizontal-axis tubed wind turbines, according to the present invention.

[0042] Figure References

[0043] 1 Horizontal rotating axis;

[0044] 2 Bushing;

[0045] 3 Rotor blades;

[0046] 4 Electric generator;

[0047] 5 Gearbox;

[0048] 6 Entrance opening;

[0049] 6a, 6b Side walls (of the entrance section);

[0050] 6c Upper wall (of the entrance section);

[0051] 6d Lower wall (of the entrance section);

[0052] 7a, 7b Side faces (of the central section);

[0053] 7c Top face (of the central section);

[0054] 7d Lower face (of the central section);

[0055] 8 Outlet opening;

[0056] 8a, 8b Lateral portions (of the exit section);

[0057] 8c Rear portion (of the exit section);

[0058] 9 Through holes;

[0059] 10 Wind turbine;

[0060] 11a, b Side parts (of the inner screen);

[0061] 11 c Top part (of the inner screen);

[0062] 11d Bottom part (of the inner screen);

[0063] E Airflow at the wind turbine inlet;

[0064] S Airflow at the outlet of the wind turbine;

[0065] D a Distance between adjacent wind turbines in the same row;

[0066] D r Wind turbine rotor diameter. or Outlet opening angle. Description of an example implementation.

[0067] Several specific examples of the invention are described below, with reference to the accompanying figures. In these figures, components with identical or similar functions have been designated using the same reference numbers.

[0068] Figures 1 and 1a are schematic views of a first wind turbine 10 according to the present invention, comprising a horizontal rotating shaft 1. One end of said rotating shaft 1 is rigidly attached to a hub 2. Furthermore, in this specific embodiment of the invention, three blades 3 are provided, each of which is connected at one end to the hub 2, to form together with this element, a rotor 2, 3. This configuration allows the rotation of the blades 2, caused by air currents, to induce, in turn, a rotation of the rotating shaft 1.

[0069] The wind turbine 10 is also equipped with an electric generator 4 connected to the rotating shaft 1 through a gearbox 5. In this way, the rotation of the rotating shaft 1 caused, as described above, by the air currents, in turn induces a rotation of the moving parts of the electric generator, giving rise to an electromotive force generated by electromagnetic induction.

[0070] The wind turbine of Figure 1 has as its main distinctive technical characteristic, which is common to all embodiments of the present invention, an external duct that covers, at least partially, the horizontal rotating shaft 1, the blades 2 and the hub 3; which, in addition, is formed by three different sections: an inlet section, a central section and an outlet section, and finally which has a geometry such that the direction of the airflow at the inlet of the duct has an angle in the range of 165°-90° with the direction of the outlet of the duct.

[0071] In the embodiment of the invention shown in Figure 1, the inlet section comprises the inlet opening 6, which allows the passage of air currents towards the rotor 2, 3 in a direction essentially perpendicular to it, i.e., horizontal, said direction being indicated by an arrow and the reference E (air inlet).

[0072] The central section is delimited by two side faces 7a, 7b, an upper face 7c, and a lower face 7d, and is configured to extend to the outlet section. Finally, the outlet section comprises two triangular side portions 8a, 8b, a rear portion 8c, and an outlet opening 8, which, in this particular embodiment of the invention, is oriented within a range from 0 o at 75°, so the airflow at the wind turbine outlet has the same range of angles. The outlet opening 8 is delimited by the two side portions 8a, 8b and the rear portion 8c. In addition, each of the side portions 8a, 8b of the outlet section is attached to one of the side faces 7a, 7b of the central section.

[0073] Figures 2a and 2b schematically illustrate a duct of a second wind turbine according to the present invention. This duct is similar to that shown in Fig. 1, but in this case, the inlet section is also provided with a funnel-shaped region formed by two side walls 6a, 6b, an upper wall 6c, and a lower wall 6d, said walls 6a, 6b, 6c, 6d being arranged to delimit the inlet opening 6.

[0074] Figure 3 shows a schematic view of a duct of a third wind turbine according to the present invention. This duct is similar to that shown in Figure 1, but it has the peculiarity that, in this instance, the lower edge of the two side portions 8a and 8b and of the rear portion 8c are not flush with the lower face 7d of the central section (as was the case in the wind turbine cover of Figure 1), but are instead below it. The position of the central section in this particularly preferred embodiment is not at the same level as the inlet section; the central section is still parallel to the inlet section but with a flat upper portion of the inlet section.

[0075] Figure 4 illustrates, schematically, a duct of a fourth wind turbine according to the present invention. This duct is similar to that shown in Fig. 2, since the inlet section is also provided, in this case, with a funnel-shaped region formed by two side walls 6a, 6b, an upper wall 6c, and a lower wall 6d. However, the embodiment shown in Figure 4 has the peculiarity that the outlet opening 8 is arranged at the top of the duct and oriented within a range of 0 o at 75°.

[0076] Figure 5 is a schematic view of a duct of a fifth wind turbine according to the present invention. This duct is similar to that shown in Fig. 1, in that the outlet section comprises two triangular side portions 8a, 8b and a rear portion 8c, as well as an outlet opening 8, oriented at angles ranging from 0° to 75°. However, the embodiment shown in Figure 5 has the peculiarity that, in this instance, the rear portion 8c of the outlet section is provided with through holes 9.

[0077] Figure 6 illustrates, schematically, a duct of a sixth ducted wind turbine according to the present invention. Said duct is similar to that shown in Fig. 1, but with a concentrator or converging body, which surrounds the original duct, comprising two side parts 7a, 7b, an upper part 7c and a lower part 7d.

[0078] Figure 7 is a schematic view of a duct of a seventh ducted wind turbine according to the present invention. This duct is similar to that shown in Fig. 1, but in this case, the outlet section is provided with only two rear portions 8c, rectangular in shape and joined together along one of their ends. Furthermore, the rear portions 8c are joined, at a first point of their common end, to the side face 7a and at a second point of their common end, to the side face 7b of the central section.

[0079] Finally, Figure 8 is a schematic view of a grouping of four ducted wind turbines as shown in Fig. 1, forming a row, according to the present invention. In this particular case, the distance D a The distance between adjacent wind turbines in the same row is approximately 1.5 to 2.5 times the diameter D r of the rotor.

[0080] The table below compares the power output of each enclosed wind turbine in a grouping similar to that shown in Fig. 8 with that of a grouping consisting of the same number of unenclosed wind turbines. The table considers three different cases, in which the row comprises 4, 3, and 2 wind turbines, respectively, with the distance between adjacent turbines also varying in each case. The power output values ​​of the invention compared to the power output of an unenclosed horizontal-axis wind turbine are expressed as a decimal. Table 1. Relationship between the power produced by the ducts included in this invention and the power produced by open horizontal axis wind turbines with the same organization and separation distance between turbines.

[0081] The results shown above were obtained using the commercial simulation software Ansys, based on the finite volume theory for fluids.

[0082] As can be seen in the table, the invention allows for the formation of a row of wind turbines by arranging them at a shorter distance from each other. In fact, it is possible to place them at a distance of only 1.5 D. r , at 2.5 D r when the usual practice in the technique is to do it within the range of 5 to 7 D rThis is due to the wake effect that appears at the rear of the wind turbines. In fact, simulations showed that in prior art wind turbine arrays (i.e., without ducts), the velocity in the wake areas behind the rotors decreased considerably. Conversely, in the case of wind turbine arrays according to the invention, the velocity contours were strengthened in the wake areas behind the ducts. Furthermore, the aerodynamic contour simulations demonstrate that the ducted wind turbine array of the invention is capable of creating semi-identical vortex regions that act as pumps to remove high-speed airflow around the ducts, thereby increasing the airflow velocity in the wake regions behind the ducts.

[0083] Thus, one of the significant characteristics of the ducted wind turbine arrays according to the present invention is that the second, third, and fourth turbines will produce more energy compared to the same uncovered turbines arranged at the same distance. In contrast, with traditional horizontal wind turbines installed in wind farms, the downstream turbines (rear turbines) will experience a decrease in power output compared to the front turbines. To mitigate this drawback, they are often arranged in the 5D range. r 7D r (D r =rotor diameter), mentioned above.

Claims

CLAIMS 1.- Horizontal axis tubed wind turbine (10) comprising: -a horizontal rotating axis (1); - a hub (2) rigidly attached to one end of the rotating shaft (1); - some blades (3), each blade (3) being connected at one of its ends to the hub (2) to jointly form a rotor (2,3), so that the rotation of the blades (2) caused by the air currents induces a rotation of the rotating shaft (1); -an electric generator (4) connected to the rotating shaft (1) through a gearbox (5); characterized in that the horizontal rotating shaft (1), the blades (2) and the hub (3) are covered, at least partially, by a duct, comprising: * an inlet section, provided with an inlet opening (6) configured to allow the passage of an airflow towards the rotor in a direction perpendicular to said rotor; * a central section, delimited, at least, by two side faces (7a, 7b), an upper face (7c) and a lower face (7d) and configured to allow the passage of the airflow to an outlet section; and * an outlet section, provided with at least one outlet opening (8), the outlet opening (8) being oriented at angles a in a range of 0-75 degrees. 2.- A ducted wind turbine (10) according to claim 1, wherein the inlet section is further provided with a funnel-shaped region comprising at least two side walls (6a, 6b), an upper wall (6c) and a lower wall (6d), said walls (6a, 6b, 6c, 6d) delimiting the inlet opening (6). 3.- A ducted wind turbine (10) according to any of the preceding claims, wherein the outlet section comprises at least two lateral portions (8a, 8b) and a portion rear (8c), the exit opening (8) being delimited by the side portions (8a, 8b) and the rear portion (8c) of the exit section. 4.- Wind turbine (10) encased according to claim 3, wherein the rear portion (8c) of the outlet section is provided with through holes (9). 5.- Wind turbine (10) encased according to any of the preceding claims, which is provided with a concentrator or converging body around it, being formed by two side parts (11a, 11b), an upper part (11c) and a lower part (11d). 6.- Wind turbine (10) encased according to any of claims 1 to 5, which is further provided with at least one solar panel, said solar panel being attached to one of the faces (7a, 7b, 7c, 7d) of the central section, to one of the walls (6a, 6b, 6c, 6d) of the funnel-shaped region and / or to one of the portions (8a, 8b, 8c) of the outlet section. 7.- Wind turbine (10) encased according to claim 3, wherein: - the central section is formed by two lateral faces (7a, 7b), an upper face (7c) and a lower face (7d), each of said faces (7a, 7b, 7c, 7d) having the shape of an isosceles trapezoid; and - the outlet section comprises an outlet opening (8) oriented essentially within a range of angles or between 0-75 degrees, delimited by two triangular-shaped side portions (8a, 8b) and a rear portion (8c), each of the side portions (8a, 8b) of the outlet section being connected to one of the side faces (7a, 7b) of the central section. 8.- Grouping of enclosed wind turbines, comprising two or more wind turbines (10) according to any of claims 1 to 7, wherein said enclosed wind turbines are arranged downstream of each other, forming at least one row, such that the inlet section of the second enclosed wind turbine is arranged behind and aligned with the central section of the first enclosed wind turbine. 9.- Grouping of horizontal axis tubed wind turbines, according to claim 8, wherein the distance between adjacent wind turbines (10) belonging to the same row is constant. 10.- Grouping of enclosed wind turbines, according to claim 9, wherein all enclosed wind turbines (10) belonging to the same row have essentially the same rotor diameter and the distance between adjacent wind turbines is proportional to said rotor diameter. 11.- Grouping of ducted wind turbines, according to claim 10, wherein the distance (Da) between adjacent wind turbines (10) in the same row is from 1.5 to 2.5 times the diameter (D r ) of the rotor.

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