Blade for wind power generator, wind power generator, and construction

Abstract

A blade (1) for a wind power generator has a surface covered with a reflective material layer (12) made of a light-reflecting material that reflects light such that, when light is incident on a compound eye of an insect, at least three types of photoreceptor cells present in the ommatidium constituting the compound eye contain visual pigments having different absorption wavelength bands, which are the wavelength bands of light to be absorbed, and the difference in light intensity in the absorption wavelength bands of the visual pigments contained respectively in multiple types of photoreceptor cells constituting a part of the ommatidium of the compound eye of the insect that are excited upon absorption of light is equal to or less than a predetermined intensity difference threshold.

Description

Blade for Wind Power Generation Device, Wind Power Generation Device, and Building

[0001] The present invention relates to a blade for a wind power generation device, a wind power generation device, and a building.

[0002] There has been proposed an illumination system that includes two types of light sources that emit lights having different spectral power distributions, and by setting the spectral power distribution of the light emitted from one of the light sources to a distribution that has a higher insect attracting effect than that of the other, insects are attracted and held on one of the two types of light sources, thereby reducing the discomfort given to people near the other light source (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2017-509321

[0004] By the way, a wind power generation device generally includes a tower, a blade attached to the upper part of the tower, and a generator that generates electricity by the rotational power generated when wind hits the blade and the blade rotates. In such a wind power generation device, when the rotational speed of the blade decreases, the power generation amount also decreases accordingly. In such a wind power generation device, it has been reported that when insects are attracted to the blade and adhere to the blade, the air resistance of the blade increases and the rotational efficiency decreases, resulting in a decrease in the power generation amount. In addition, wind power generation devices are often installed in natural-rich locations where the wind conditions are relatively good throughout the year. For this reason, it has also been pointed out that the balance of the ecosystem at the installation location of the wind power generation device is being disrupted because insects inhabiting near the installation location of the wind power generation device and flying animals that feed on insects are attracted to the rotating blades of the wind power generation device and hit the blades and die.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a blade for a wind power generation device, a wind power generation device, and a building that can maintain the power generation amount by making it difficult for insects to be attracted and can conserve the environment.

[0006] To achieve the above objective, the blade for a wind power generation device according to the present invention has a surface covered with a reflective material layer made of a light-reflecting material that reflects light such that, when light is incident on the compound eye of an insect, at least three types of photoreceptor cells present in the ommatidia that make up the compound eye have different absorption wavelength bands, and the difference in light intensity in the absorption wavelength band of the photoreceptor cells contained in each of the multiple types that make up a part of the ommatidia of the insect compound eye that are excited when light is absorbed is less than or equal to a preset intensity difference threshold.

[0007] According to the present invention, the surface is covered with a reflective material layer made of a light-reflecting material that reflects light such that, when light is incident, the difference in light intensity in the absorption wavelength band of each of the multiple types of photoreceptor cells that constitute a part of the insect's eye is below a preset intensity difference threshold. As a result, insects are less likely to be attracted to the blades of the wind turbine, thus suppressing the attachment of insects to the blades and maintaining the power generation capacity of the wind turbine. Furthermore, by suppressing the attachment of insects to the blades, the environment of the location where the wind turbine is installed can be preserved.

[0008] This is a schematic diagram showing the simultaneous image eye of an insect. This is a schematic diagram showing the overlapping image eye of an insect. This is a schematic diagram of an insect ommatidia. This is a cross-sectional view of an insect ommatidia broken along line A-A in Figure 2A. This is a diagram showing the absorption wavelength bands of the visual pigments contained in each photoreceptor cell that makes up a part of the insect eye. This is a photograph of the exterior of a Mirabilis jalapa. This is a diagram showing the reflected light spectrum of the petal portion of a Mirabilis jalapa. This is a diagram showing the reflected light spectrum of the leaf portion of a Mirabilis jalapa. This is a photograph of the exterior of a Toad Lily. This is a diagram showing the reflected light spectrum of the petal portion of a Toad Lily. This is a diagram showing the reflected light spectrum of the leaf portion of a Toad Lily. This is a diagram showing the spectral spectrum of light that can be used to attract insects. This is a photograph of the exterior of a Magnolia denudata. This is a diagram showing the reflected light spectrum of the petal portion of a Magnolia denudata. This is a schematic diagram of the compound eye of an insect. This is a schematic diagram of an insect ommatidia. This is a schematic diagram showing the case when the distance between the target object and the eye is relatively short. This is a schematic diagram showing the case when the distance between the target object and the eye is relatively long. This is a schematic diagram of a wind power generation device according to an embodiment. This is a cross-sectional view of a part of the blade for a wind power generation device according to an embodiment. This is a diagram showing the spectral spectrum of light emitted from a reflective member according to the example and comparative example. This is a diagram showing the number of insects attached to the reflective member according to the example and comparative example. This is a diagram showing the schematic configuration of a modified wind power generation system.

[0009] Embodiments of the present invention will be described below with reference to the accompanying drawings. The blade for a wind power generation device according to this embodiment includes a reflective member that reflects light such that when light is incident, the absorption wavelength bands of the light absorbed are different from each other, and all of the multiple types of photoreceptor cells that constitute a part of the eye of an insect, which are excited when light is absorbed by the visual pigment, are excited to approximately the same degree, or a light-emitting member that emits light such that all of the multiple types of photoreceptor cells are excited to approximately the same degree.

[0010] Here, the structure of the insect eye, which is the premise of the present invention, will be described. Insects with compound eyes include diurnal insects and nocturnal insects. Diurnal insects have a combined image eye CE1 formed by the aggregation of multiple ommatidia, for example, as shown in Figure 1A. Nocturnal insects, on the other hand, have a superimposed image eye CE2 including a transparent layer CL, for example, as shown in Figure 1B. As shown in Figure 1A, the combined image eye CE1 has a plurality of corneal units CU, a conical crystalline structure CR provided one at a time for each of the plurality of corneal units CU, photoreceptor cells RE provided on the side of the conical crystalline structure CR opposite to the corneal unit CU, and optic nerves NO continuous with the photoreceptor cells RE. On the other hand, as shown in Figure 1B, the simultaneous image eye CE1 has a plurality of corneal units (CUs), a conical crystalline structure (CR) provided one per corneal unit (CU), photoreceptor cells (REs) provided spaced apart from the conical crystalline structure (CR) on the side opposite to the corneal unit (CU) on the conical crystalline structure (CR), an optic nerve (NO) continuous with the photoreceptor cells (REs), and a transparent layer (CL) interposed between the conical crystalline structure (CR) and the photoreceptor cells (REs). The plurality of photoreceptor cells (REs) are arranged to surround the rhabdomen (RH), which is a photoreceptor site located along the optical axis of the lens system consisting of a pair of corneal units (CUs) and a conical crystalline structure (CR). Furthermore, each of the plurality of photoreceptor cells (REs) contains a visual pigment with different absorption wavelength bands for the wavelengths of light it absorbs. Then, as shown in Figure 2A, for example, the photoreceptor cells RE_L, RE_M, and RE_S are arranged so that the visual pigment-containing parts P_L, P_M, and P_S are adjacent to each other, thereby forming a lab dome RH consisting of the visual pigment-containing parts P_L, P_M, and P_S. Here, L, M, and S represent long wavelength, medium wavelength, and short wavelength, respectively. The focal length of an ommatidia is several centimeters to about 50 centimeters, and insects cannot change this distance. Therefore, if an object is farther away from the ommatidia than its focal length, the image of that object cannot be formed on the lab dome RH. Also, if an object has multiple colors, the light corresponding to each color emitted from the object will mix and enter the lab dome RH. On the other hand, insects have high temporal resolution and can spatially perceive wind turbine blades that rotate at rotational speeds that cannot be spatially perceived by the human eye.

[0011] As shown in Figure 2B, the lab dome RH is formed in the portion adjacent to the lens system consisting of the corneal CU and conical crystalline body CR. These visual pigment-containing portions P_L, P_M, and P_S each have a structure with numerous protruding microvilli, and these microvilli contain visual pigment. The refractive index of the lab dome RH is higher than that of the photoreceptor cell RE other than the visual pigment-containing portions P_L, P_M, and P_S, and it functions as an optical waveguide for light incident on the lab dome RH from the lens system consisting of the corneal CU and conical crystalline body CR. Therefore, as shown by the arrow Li in Figure 2B, light incident on the lab dome RH from the lens system consisting of the corneal CU and conical crystalline body CR propagates within the lab dome RH. Some insects have a superimposed image eye in which a transparent layer is interposed between the lens system consisting of multiple corneal CUs and multiple conical crystalline bodies CR and the photoreceptor cell RE.

[0012] Furthermore, the photoreceptor cells RE_L, RE_M, and RE_S each have visual pigment-containing portions P_L, P_M, and P_S, respectively, which contain visual pigments with different absorption wavelength bands for the light they absorb. For example, in the photoreceptor cell RE_L, a visual pigment-containing portion P_L is formed, which contains a visual pigment with an absorption wavelength band of 450 nm to 700 nm, as shown by the curve S_L in Figure 3. In the photoreceptor cell RE_M, a visual pigment-containing portion P_M is formed, which contains a visual pigment with an absorption wavelength band of, for example, 350 nm to 550 nm, as shown by the curve S_M in Figure 3. In addition, in the photoreceptor cell RE_S, a visual pigment-containing portion P_S is formed, which contains a visual pigment with an absorption wavelength band of, for example, 300 nm to 400 nm, as shown by the curve S_S in Figure 3. Photoreceptor cells RE_L are excited when they absorb light with a wavelength range of 450 nm to 700 nm by visual pigments, and photoreceptor cells RE_M are excited when they absorb light with a wavelength range of 350 nm to 550 nm by visual pigments. In addition, photoreceptor cells RE_L are excited when they absorb light with a wavelength range of 450 nm to 700 nm by visual pigments.

[0013] Based on the above explanation, the inventors investigated the reflected light spectra of flowers that attract insects in nature. When the reflected light spectra were measured from each of the five locations on the petal portion of the Mirabilis jalapa flower shown in Figure 4A, reflected light spectra S11, S12, S13, S14, and S15 were measured, as shown in Figure 4B, in which the intensity in the wavelength region between 500 nm and 600 nm was lower than the intensity in the wavelength regions around 400 nm and above 650 nm. Furthermore, when the reflected light spectra were measured from each of the four locations on the leaf portion of the Mirabilis jalapa flower shown in Figure 4A, reflected light spectra S16, S17, S18, and S19 were measured, as shown in Figure 5, in which the contrast between the intensity in the wavelength region between 500 nm and 600 nm and the intensity in the wavelength regions around 400 nm and above 650 nm was smaller compared to the petal portion. Furthermore, when the reflected light spectra were measured from each of the five locations on the petal portion of the "Toad Lily" shown in Figure 6A, as shown in Figure 6B, reflected light spectra S21, S22, S23, S24, and S25 were measured in which the intensity in the wavelength region around 550 nm was lower than the intensity in the wavelength regions around 450 nm and above 650 nm. In addition, when the reflected light spectra were measured from each of the six locations on the leaf portion of the "Toad Lily" shown in Figure 6A, as shown in Figure 7, reflected light spectra S26, S27, S28, S29, S30, and S31 were measured in which the contrast between the intensity in the wavelength region around 550 nm and the intensity in the wavelength regions around 450 nm and above 650 nm was smaller compared to the petal portion. From these results, it was found that insects are attracted to flowers that reflect light with reflected light spectra that have peaks on the long-wavelength and short-wavelength sides, in other words, dips where the intensity is lower. Specifically, we found that insects are more easily attracted to flowers that reflect light whose reflected light spectrum is larger when the sum of the intensities of each component corresponding to the absorption wavelength band between 300 nm and 400 nm of the visual pigment contained in photoreceptor cell RE_S, and the sum of the intensities of each component corresponding to the absorption wavelength band between 450 nm and 700 nm of the visual pigment contained in photoreceptor cell RE_L, is larger than the sum of the intensities of each component corresponding to the absorption wavelength band between 350 nm and 550 nm of the visual pigment contained in photoreceptor cell RE_M.Furthermore, since insects tend to be attracted to the petals of flowers more than the leaves, it was found that the greater the contrast in intensity, the easier it is for insects to be attracted.

[0014] From this, the inventors found that a light source that emits light having a spectral spectrum in which the sum of the intensities of each component corresponding to the absorption wavelength band between 300 nm and 400 nm of the visual pigment contained in photoreceptor cell RE_S, and the sum of the intensities of each component corresponding to the absorption wavelength band between 450 nm and 700 nm of the visual pigment contained in photoreceptor cell RE_L is greater than the sum of the intensities of each component corresponding to the absorption wavelength band between 350 nm and 550 nm of the visual pigment contained in photoreceptor cell RE_M, has a high insect-attracting effect. In other words, as shown in Figure 8, the inventors found that a light-reflecting material that reflects or a light source that emits light having a spectral spectrum S51 with intensity peaks in the wavelength bands between 300 nm and 400 nm and between 450 nm and 700 nm, and a dip in intensity in the wavelength band between 350 nm and 550 nm has a high insect-attracting effect.

[0015] Furthermore, as shown in Figure 9A, in petals that appear white to humans, as shown in the reflected light spectra S41 to S47 in Figure 9B, there is almost no reflection below 400 nm, the reflection increases sharply from the wavelength band above 400 nm and remains high and almost constant from 400 nm to the longer wavelength side. We have found that light-reflecting materials or light sources that emit light that appears white to humans due to the lack of reflection below 400 nm also have a high insect-attracting effect. In other words, we have found that light-reflecting materials or light sources that emit light having the spectral spectra S51 and S52 in Figure 8 have a high insect-attracting effect.

[0016] In simultaneous-image or superimposed-image eyes, light incident from a target relatively far from the eye enters one or a few individual ommatidia. In simultaneous-image eyes, the field of view of each individual ommatidia is about 1 to 2 degrees, allowing one or a few ommatidia to receive light. In superimposed-image eyes, light incident on multiple ommatidia is focused by the cornea and crystalline cone, passes through the transparent layer (CL), and enters one or a few lab domes. In this case, if the lab domes are formed from photoreceptor cells excited by light in different wavelength bands, the wavelength information of the light is retained, allowing for discrimination of wavelength information in the form of differences in the excitation of different photoreceptor cells. However, so-called spatial information, such as the shape of the target or the distance to the target, is lost. For example, as shown in Figure 10, the spatial discrimination world of insects is determined by both the angular sensitivity A11 of the ommatidia and the interommatidal angle A12. As mentioned earlier, each ommatidia of an insect consists of a lens system comprising a cornea and a cone, and a labome, which is a light-receiving area emitted by photoreceptor cells near the optical axis. As shown in Figure 11A, the field of view of each ommatidia is narrow, about 1 to 2 degrees. As shown in Figure 11B, when an insect is close to a flower, multiple ommatidia receive light individually, allowing for the reception of spatial information, identification of the flower's shape, and improved wavelength discrimination. In other words, for targets close to the insect, information about shape and wavelength discrimination can be obtained. On the other hand, as shown in Figure 11C, when an insect moves away from a flower, due to the influence of the ommatidia's angular sensitivity A11 and interommatidia angle A12, only one or a few ommatidia can receive light. As a result, information about shape and distance is lost. In other words, for targets far from the insect, the visible range is determined by the angular sensitivity A11 and interommatidia angle A12 of each ommatidia. In a simultaneous image eye, only the lab dome of one, or at most a few, ommatidia receives light, so shape information is lost. In a duplicated image eye, light incident on the corneas of many ommatidia is focused on the lab dome of a single ommatidia. Since that single lab dome receives light from the outside world, shape information is lost. Insects are thought to have evolved to distinguish targets from the background and survive without shape information by using wavelength contrast information, that is, spectral spectra with so-called valleys, to distinguish targets.From this, it is highly likely that flowers that are effective in attracting insects stabilize the information acquisition for insects by reflecting light with a wavelength-dependent reflected light spectrum, that is, light with contrast in intensity due to differences in wavelength (see Figure 8). In other words, due to the structure of their eyes, insects cannot distinguish the shape of targets located at a relatively far distance, and it is thought that the waveform information incident on the ommatidia, that is, spectral information, acts as the trigger for their attraction behavior.

[0017] The wind power generation device 100 according to this embodiment typically comprises three wind power generation device blades 1, a rotor 2 (nacelle) that rotates the wind power generation device blades 1, and a support column 3 (tower) that supports the rotor 2, as shown in Figure 12A, for example. The wind power generation device blades 1 were invented based on the knowledge regarding the insect attraction results to the so-called valleys in the spectral spectrum. That is, as shown in Figure 12B, the surface of the blade base material 11 of the wind power generation device blade 1 is covered with a reflective material layer 12 made of a light-reflecting material that reflects light having a spectral spectrum in which the valleys disappear. In other words, the surface of the wind power generation device blade 1 is covered with a reflective material layer 12 made of a light-reflecting material that reflects light such that, when light is incident, the difference in the intensity of light in the absorption wavelength bands of the visual pigments contained in each of the multiple types of photoreceptor cells that constitute a part of the eye of an insect, which contains visual pigments with different absorption wavelength bands, is less than or equal to a preset intensity difference threshold. Furthermore, it is preferable that the light emitted from the reflective material layer 12 has an intensity difference of 25% or less at each wavelength in its spectral spectrum. In addition, the light-reflecting material forming the light-reflecting material layer 12 may be not only a paint that reflects light having the aforementioned spectral spectrum, but also a metal or resin film that reflects light having the aforementioned spectral spectrum.

[0018] Here, we will explain the results of an experiment comparing the number of insects attached to reflective members according to the examples and comparative examples of the present invention (see Figures 13A and 13B). For the reflective members in the examples and comparative examples, we used a canvas measuring 33.3 cm × 24.4 cm with various light-reflective materials applied to its surface. For the light-reflective materials used in the reflective members of Comparative Examples 1 and 2, we used materials having a reflectance spectrum in which the reflectance decreases sharply from around 400 nm wavelength, as shown in Figure 13A. Comparative Example 1 is a paint used in current wind power generation facilities. Comparative Example 2 is a material that exhibits a spectral curve similar to that of a white flower. On the other hand, for the light-reflective materials used in the reflective members of Examples 1 to 4 of the present invention, we used materials having a reflectance spectrum in which the difference in reflectance at each wavelength is 25% or less, as shown in Figure 13A. In this experiment, the reflective members according to the comparative examples and examples were left on the roof of a building at Hamamatsu University School of Medicine for four days, and the number of insects attached to the surface of the reflective members was measured 10 times. The average values ​​of the 10 measurements were then compared.

[0019] Figure 13B shows the number of insects attached to the reflective members of the example and the comparative example. As shown in Figure 13B, it was found that the number of insects attached to the reflective member of the example was reduced by at least 40% compared to the number of insects attached to the reflective member of the comparative example. From this result, it was found that the reflective member of the example is more effective in reducing insect attachment than the reflective member of the comparative example. In other words, it was found that it is preferable for the intensity difference at each wavelength in the spectral spectrum of the light reflected by the reflective member to be 25% or less.

[0020] As described above, the blade 1 for the wind turbine according to this embodiment has its surface covered with a reflective material layer 12 made of a light-reflecting material that reflects light such that, when light is incident on it, the difference in light intensity in the absorption wavelength band of each of the multiple types of photoreceptor cells that constitute a part of the insect's eye is below a preset intensity difference threshold. As a result, insects are less likely to be attracted to the blade 1 for the wind turbine, thus suppressing the attachment of insects to the blade 1 and maintaining the power generation amount of the wind turbine 100. Furthermore, by suppressing the attachment of insects to the blade 1 for the wind turbine, the environment of the location where the wind turbine 100 is installed can be preserved.

[0021] Although embodiments of the present invention have been described above, the present invention is not limited to the configuration of the embodiments described above. For example, as in the wind power generation system shown in Figure 14, a light source 200 for attracting insects and a reflective member 300 may be placed at a distance from the location where the wind power generation device 2100, which is equipped with wind power generation device blades 2001, is installed, so that insects do not approach the wind power generation device blades. Furthermore, as the light source 200 for attracting insects, a device that emits light having a spectral spectrum with intensity peaks in the wavelength bands of 300 nm to 400 nm and 450 nm to 700 nm, and a dip in intensity in the wavelength band of 350 nm to 550 nm, as shown in Figure 8, can be used. Furthermore, as the reflective member 300 for attracting insects, a device that reflects light having a spectral spectrum with intensity peaks in the wavelength bands of 300 nm to 400 nm and 450 nm to 700 nm, and a dip in intensity in the wavelength band of 350 nm to 550 nm, as shown in Figure 8, when sunlight is incident on it can be used.

[0022] In this case, during the day, the wind turbine blade 2001 reflects sunlight relatively flatly across the entire wavelength band from 300 nm to 700 nm, making it difficult for insects to identify the wind turbine blade 2001 and thus less likely to be attracted to it. On the other hand, the reflective member 300 reflects light that attracts insects, so insects are attracted to the reflective member 300. On the other hand, at night, the wind turbine blade 2001 emits light that is relatively flat across the entire wavelength band from 300 nm to 700 nm, making it difficult for insects to identify the wind turbine blade 2001 and thus less likely to be attracted to it. On the other hand, the light source 200 emits light that attracts insects, so insects are attracted to the light source 200. Thus, according to this modified example, it is possible to suppress insects from approaching the wind turbine blade 2001.

[0023] In the wind power generation device according to the embodiment, a marker light may be installed at the tip of the support column 3. In this case, it is preferable that the marker light emits light having a spectral spectrum such that the intensity gradually increases toward longer wavelengths in the wavelength band of 300 nm to 640 nm, and the rate of increase of intensity with respect to wavelength is substantially constant.

[0024] Furthermore, the exterior wall of a building may be covered with a reflective material layer that reflects light such that, when light is incident, the difference in light intensity in the absorption wavelength bands of the visual pigments contained in each of several types of photoreceptor cells that make up part of the eye of an insect, which contain visual pigments with different absorption wavelength bands, is below a predetermined intensity difference threshold.

[0025] Although embodiments and variations of the present invention have been described above, the present invention is not limited thereto. The present invention includes embodiments and variations that are appropriately combined, and those that are appropriately modified thereto.

[0026] This application is based on Japanese Patent Application No. 2024-165450, filed on 24 September 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-165450 are incorporated herein by reference.

[0027] The present invention is suitable as a blade for a wind turbine or a wind turbine for preventing insect damage caused by insects.

[0028] 1: 2001: Blade for wind turbine, 2: Rotor (nacelle), 3: Support column (tower), 100, 2100: Wind turbine, 200: Light source, 300: Reflective member, CE1: Simultaneous image eye, CE2: Overlapping image eye, CL: Transparent layer, CR: Crystal cone, CU: Cornea, NO: Optic nerve, P_L, P_M, P_S: Visual pigment-containing part, RE, RE_L, RE_M, RE_S: Photoreceptor cell, RH: Photoreceptor rod (Lab dome)

Claims

1. A wind turbine blade, wherein when light enters the compound eye of an insect, at least three types of photoreceptor cells present within the ommatidia constituting the compound eye contain visual pigments with different absorption wavelength bands, and the surface of the blade is covered with a reflective material layer made of a light-reflecting material that reflects light such that the difference in light intensity in the absorption wavelength band of the visual pigments contained in each of the multiple types of photoreceptor cells constituting a part of the ommatidia constituting the compound eye that are excited when light is absorbed is less than or equal to a preset intensity difference threshold.

2. The blade for a wind turbine according to claim 1, wherein the light reflected by the light-reflecting material has a spectrum in which the difference in light intensity at different wavelengths is 25% or less in the wavelength band of 300 nm to 700 nm.

3. A wind power generation device that generates electricity by rotating blades for a wind power generation device, wherein the blades for the wind power generation device are covered on the surface with a reflective material layer made of a light-reflecting material that reflects light such that, when light is incident on the compound eye of an insect, at least three types of photoreceptor cells present in the ommatidia constituting the compound eye have different absorption wavelength bands, and the difference in light intensity in the absorption wavelength band of the photoreceptor cells contained in each of the multiple types of photoreceptor cells constituting a part of the ommatidia constituting the compound eye of the insect is below a preset intensity difference threshold.

4. A structure in which, when light enters an insect compound eye, at least three types of photoreceptor cells present within the ommatidia constituting the compound eye contain visual pigments with different absorption wavelength bands, and the surface is covered with a reflective material layer made of a light-reflecting material that reflects light such that the difference in light intensity in the absorption wavelength band of the visual pigments contained in each of the multiple types of photoreceptor cells constituting a part of the ommatidia constituting the insect compound eye that are excited when light is absorbed is less than or equal to a predetermined intensity difference threshold.

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