JP2010097973A - Light energy collecting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light energy collecting apparatus capable of taking out large photoelectric conversion output even when the installation area of a solar cell or the like is small, suppressing the temperature rise of a photoelectric conversion element and effectively utilizing thermal energy included in incident light. <P>SOLUTION: A concave mirror 12 reflects and condenses sunlight 22. A cold mirror 14 makes the condensed light 22 be incident, reflects visible light 22a included in the light 22, and transmits infrared light 22b. The solar cell 16 receives the visible light 22a and generates photovoltaic force. A heat utilizing element 18 such as a thermoelectric conversion element, a stirling engine, a water heater or a steam turbine power generator receives the infrared light 22b and utilizes the thermal energy of the infrared ray 22b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for collecting energy from infrared light and visible light radiated from a light source such as the sun, and can extract a large photoelectric conversion output even if the installation area of a photoelectric conversion element such as a solar cell is small. In addition, the temperature rise of the photoelectric conversion element can be suppressed, and furthermore, the thermal energy contained in the incident light can be used effectively.

  There existed what was described in the following patent documents 1-4 as a conventional solar energy collection apparatus which produces | generates warm water simultaneously with receiving sunlight. The device described in Patent Document 1 is a solar cell and a water heater arranged side by side. Of the sunlight received on the solar cell side, the light on the long wavelength side that did not contribute to power generation is reflected on the water heater side and used.

  The device described in Patent Document 2 is a solar battery stacked on a water heater. Solar cells generate power using visible light contained in sunlight and transmit infrared light. The water heater uses the infrared light that has passed through the solar cell to generate hot water.

  The device described in Patent Document 3 collects sunlight with a condenser lens and irradiates the solar cell. When the solar cell is irradiated with the concentrated sunlight, the temperature of the solar cell rises and the power generation efficiency is lowered. Therefore, the light receiving surface of the solar cell is exposed in the pipe through which the refrigerant is passed, and the light transmission window formed in the pipe The sunlight is irradiated onto the light receiving surface of the solar cell.

  The device described in Patent Document 4 has a wavelength selective reflection / transmission film disposed on the surface of a solar cell arranged in a concave shape. Light having a short wavelength that has passed through the wavelength selective reflection / transmission film is received by the solar cell, and light having a long wavelength reflected and collected by the wavelength selection reflection / transmission film is received by the thermoelectric power generation element, and power is generated. Each of the solar cell and the thermoelectric power generation element is cooled with cooling water, and the cooling water is heated in the cooling process to become hot water and used for hot water supply.

Japanese Utility Model Publication No. 05-66473 JP 2006-317128 A Japanese Patent Laid-Open No. 9-213980 JP 11-31835 A

  According to the device described in Patent Document 1, since solar cells and water heaters are arranged side by side, when the installation space is limited (for example, on the roof of a house), each is individually compared to the case where each is installed alone. Allocatable installation space was narrow. In this case, long-wavelength light that has not contributed to power generation among the sunlight received on the solar cell side is reflected and used on the water heater side, but it is used to heat water in the sunlight received on the water heater side. Since the light on the short wavelength side that did not contribute is not used for power generation, the utilization efficiency of solar energy was poor.

  According to the device described in Patent Document 2, the water heater and the solar cell are arranged in an overlapping manner, so that each installation space can be increased compared to the device of Patent Document 1. However, since the energy obtained by the solar cell is determined by the installation area of the solar cell, it is necessary to install a large number of expensive solar cells in order to obtain large energy. Further, in any of the devices disclosed in Patent Documents 1 and 2, since the solar cell is directly irradiated with sunlight, a temperature increase of the solar cell is unavoidable, and there is a problem that power generation efficiency is lowered.

  According to the apparatus described in Patent Document 3, sunlight is collected by the condenser lens and irradiated to the solar cell, so that a large output can be taken out by a small-area solar cell. However, since the heat energy of the refrigerant heated by the cooling of the solar cell is not used, the use efficiency of the solar energy is poor.

  According to the apparatus described in Patent Document 4, since the wavelength selective reflection / transmission film is disposed on the surface of the solar cell and the light (heat ray) having a long wavelength is reflected, the temperature increase of the solar cell can be suppressed. However, since the energy obtained by the solar cell is determined by the installation area of the solar cell, it is necessary to install a large number of expensive solar cells in order to obtain large energy. In particular, in this apparatus, the solar cells are arranged in a curved surface, so that the installation area of the solar cells required to receive sunlight with the same cross-sectional area is larger than that in the case where the solar cells are arranged in a flat shape, which is expensive. It was necessary to install many solar cells.

  The present invention has been made in view of the above points, and can extract a large photoelectric conversion output even when the installation area of a photoelectric conversion element such as a solar cell is small, and can suppress an increase in temperature of the photoelectric conversion element. In addition, the present invention intends to provide a light energy collecting device that can effectively use thermal energy contained in incident light.

  The present invention is a concave mirror that reflects and collects light from a light source including infrared light and visible light, and separates visible light and infrared light contained in the light by entering the collected light. A wavelength selection element; a photoelectric conversion element that receives the separated visible light to generate photovoltaic power; and a heat utilization element that receives the separated infrared light and uses thermal energy of the infrared light. It is provided.

  According to the present invention, since the light from the light source is collected by the concave mirror and received by the photoelectric conversion element, a large photoelectric conversion output can be taken out even if the installation area of the photoelectric conversion element is small. In addition, visible light and infrared light contained in the light from the light source are separated by the wavelength selection element, and the photoelectric conversion element receives the separated visible light, so that the temperature rise of the photoelectric conversion element can be suppressed. . Furthermore, since the heat utilization element receives the separated infrared light, the thermal energy contained in the light from the light source can be used effectively.

  In the present invention, for example, the wavelength selection element can be constituted by a cold mirror that reflects visible light and transmits infrared light. In this case, the photoelectric conversion element receives visible light reflected by the cold mirror, and the heat utilization element can be arranged to receive infrared light transmitted through the cold mirror. In the present invention, the wavelength selection element may be a cold filter that transmits visible light and reflects infrared light. In this case, the photoelectric conversion element can be disposed so as to receive visible light transmitted through the cold filter, and the heat utilization element can receive infrared light reflected by the cold filter.

  In the present invention, the specular shape of the concave mirror can be a paraboloid, a spherical surface, an elliptical surface, or the like. Further, the shape of the incident surface of the wavelength selection element can be a convex surface (hyperboloid, spherical surface, etc.), a flat surface, or the like. Moreover, the mirror surface shape of the concave mirror may be a semi-cylindrical concave surface, and the wavelength selection element may be a semi-cylindrical convex surface, a flat surface, or the like. Further, the convex surface or the semi-cylindrical convex surface of the wavelength selection element can be constituted by a continuous surface or a Fresnel surface. Further, the concave surface of the concave mirror can be constituted by a continuous surface or a Fresnel surface.

  In the present invention, the heat utilization element can be, for example, a thermoelectric conversion element, a Stirling engine, a water heater, a steam turbine generator, or the like.

Embodiment 1
Embodiment 1 of the light energy collecting apparatus of the present invention is shown in FIG. The light energy collecting device 10 includes a concave mirror 12, a wavelength selection element 14, a photoelectric conversion element 16, and a heat utilization element 18. The concave mirror 12 has a mirror surface formed in a paraboloid. The paraboloid axis 20 is arranged parallel or substantially parallel to the incident light 22. As shown in FIG. 1B, the concave mirror 12 is formed in a semicircular shape when viewed from the direction of the shaft 20. The concave mirror 12 receives sunlight as light 22 from a light source including infrared light and visible light, and reflects and collects the sunlight 22 as it is (including infrared light and visible light). The condensed light is focused on the focal position A of the concave mirror 12.

  The wavelength selection element 14 is disposed in the middle of the optical path from the concave mirror 12 to the focal position A of the concave mirror 12. The wavelength selection element 14 is formed as a hyperboloid having a convex incident surface shape. The axis of the hyperboloid is arranged at the same position as the axis 20 of the concave mirror 12. As shown in FIG. 1B, the wavelength selection element 14 is formed in a semicircular shape when viewed from the direction of the axis 20. In this embodiment, the wavelength selection element 14 is a cold mirror. Sunlight 22 reflected and collected by the concave mirror 12 is incident on the cold mirror 14. The cold mirror 14 reflects the visible light 22a out of the light in each wavelength region included in the incident sunlight 22, and transmits the infrared light 22b. An example of the transmittance characteristic of the cold mirror 14 is shown in FIG. In this characteristic example, in addition to visible light, light in a region having a shorter wavelength than visible light is reflected.

  The visible light 22a reflected by the cold mirror 14 is focused on a position B on the axis 20 (position close to the concave mirror 12). The photoelectric conversion element 16 is disposed at the focal position B on the shaft 20 or in the vicinity thereof (a position where the visible light 22a can be received), with the light receiving surface disposed at a right angle to the shaft 20 toward the cold mirror 14. The photoelectric conversion element 16 is composed of a solar cell. As the solar cell 16, a crystalline silicon solar cell, a GaAs-based solar cell, or the like that can obtain high conversion efficiency with respect to visible light is used. The visible light 22 a reflected by the cold mirror 14 is received by the solar cell 16. Thereby, the solar cell 16 generates photovoltaic power. The generated photovoltaic power is used for an appropriate power source.

  The heat utilization element 18 is disposed at the focal position A of the concave mirror 12 on the opposite side of the concave mirror 12 with the cold mirror 14 interposed therebetween or in the vicinity thereof (position where the infrared light 22b can be received). The heat utilization element 18 is composed of a device that operates with thermal energy, such as a thermoelectric conversion element, a Stirling engine, or a water heater. The infrared light 22 b that has passed through the cold mirror 14 is received by the heat utilization element 18. Accordingly, the heat utilization element 18 generates power if it is a thermoelectric conversion element, rotates if it is a Stirling engine, and heats water if it is a water heater.

  According to the light energy collecting apparatus 10 having the above configuration, the sunlight 22 is collected by the concave mirror 12 and irradiated to the solar cell 16, so that a large photoelectric conversion output can be taken out even if the installation area of the solar cell 16 is small. it can. Similarly, since the sunlight 22 is condensed by the concave mirror 12 and applied to the heat utilization element 18 with respect to the heat utilization element 18, a large output can be taken out even if the heat utilization element 18 is small. And since the light 22a which injects into the solar cell 16 is the light which removed the infrared light with the cold mirror 14, the temperature rise of the solar cell 16 can be suppressed and the fall of a light conversion output can be suppressed. Furthermore, since the infrared light 22b separated by the cold mirror 14 is utilized by the heat utilization element 18, the energy utilization efficiency of the sunlight 22 can be enhanced. In addition, since the sunlight 22 is condensed by the concave mirror 12 and then irradiated to the wavelength selection element 14, the wavelength is compared with a case where a wavelength selective reflection / transmission film is arranged on the surface of the solar cell as in the device described in Patent Document 4. The installation area of the selection element 14 can be reduced. Further, since the concave mirror 12 is used for condensing, the cost can be reduced as compared with the case using the condensing lens of Patent Document 3.

  In Embodiment 1, the mirror surface shape of the concave mirror 12 is a paraboloid, and the incident surface shape of the cold mirror 14 is a hyperboloid, but instead, the mirror surface shape of the concave mirror 12 is a spherical surface although some aberrations occur. Alternatively, an elliptical surface may be used, and the incident surface shape of the cold mirror 14 may be a spherical surface. A hyperboloid shape is difficult to manufacture, but a spherical surface makes it easier to manufacture.

  In the first embodiment, the shape of the incident surface of the cold mirror 14 is a convex surface, but it may be a flat surface. However, the position B where the visible light 22a reflected by the cold mirror 14 is focused becomes a position away from the wavelength selection element 14 in the convex surface, and the solar cell 16 can be arranged away from the wavelength selection element 14. The arrangement of the solar cell 16 is facilitated.

  In the first embodiment, the wavelength selection element 14 is configured by a cold mirror, but may be configured by a cold filter. The cold filter reflects infrared light among light in each wavelength region included in incident sunlight and transmits visible light. An example of the transmittance characteristic of the cold filter is shown in FIG. When the wavelength selection element 14 is constituted by a cold mirror, the arrangement of the solar cell 16 and the heat utilization element 18 is interchanged in FIG.

<< Embodiment 2 >>
Embodiment 2 of the light energy collecting apparatus of the present invention is shown in FIG. In this embodiment, the concave mirror 12 and the wavelength selection element 14 are formed in a semicircular shape as viewed from the direction of the axis 20 in the first embodiment, but are formed in a circular shape. The same reference numerals are used for portions common to the first embodiment. The light energy collecting device 24 includes a concave mirror 26, a wavelength selection element 28, a photoelectric conversion element 16, and a heat utilization element 18. The concave mirror 26 has a mirror surface formed as a paraboloid. The parabolic axis 20 is arranged parallel or substantially parallel to the incident sunlight 22. As shown in FIG. 4B, the concave mirror 26 has a circular shape when viewed from the direction of the shaft 20. The concave mirror 26 receives sunlight 22 and reflects and collects the sunlight 22 as it is. The condensed light is focused on the focal position A of the concave mirror 26.

  The wavelength selection element 28 is disposed in the middle of the optical path from the concave mirror 26 to the focal position A of the concave mirror 26. The wavelength selection element 28 is formed as a hyperboloid having a convex incident surface. The axis of the hyperboloid is arranged at the same position as the axis 20 of the concave mirror 26. As shown in FIG. 4B, the wavelength selection element 28 is formed in a circular shape when viewed from the direction of the axis 20. In this embodiment, the wavelength selection element 28 is constituted by a cold filter. The sunlight 22 reflected and collected by the concave mirror 26 is incident on the cold filter 28. The cold filter 28 transmits visible light 22a out of light in each wavelength region included in incident sunlight 22, and reflects infrared light 22b. The transmittance characteristic of the cold filter 28 can be the same as that shown in FIG. 3, for example.

  The photoelectric conversion element 16 has a light receiving surface disposed at a right angle to the axis 20 at a focal position A of the concave mirror 26 on the opposite side of the concave mirror 26 with the cold filter 28 interposed therebetween or a position near the focal position A (a position where the visible light 22a can be received). It is arranged toward the cold filter 28. The photoelectric conversion element 16 is composed of a solar cell. As the solar cell 16, a crystalline silicon solar cell, a GaAs-based solar cell, or the like that can obtain high conversion efficiency with respect to visible light is used. The visible light 22 a that has passed through the cold filter 28 is received by the solar cell 16. Thereby, the solar cell 16 generates photovoltaic power. The generated photovoltaic power is used for an appropriate power source.

  The infrared light 22b reflected by the cold filter 28 is focused on a position B on the axis 20 (a position near the surface of the concave mirror 26). The heat utilization element 18 is disposed at the focal position B on the shaft 20 or in the vicinity thereof (a position where the infrared light 22b can be received). The heat utilization element 18 is composed of a device that operates with thermal energy, such as a thermoelectric conversion element, a Stirling engine, or a water heater. The infrared light 22 b reflected by the cold filter 28 is received by the heat utilization element 18. Accordingly, the heat utilization element 18 generates power if it is a thermoelectric conversion element, rotates if it is a Stirling engine, and heats water if it is a water heater.

  According to the light energy collecting device 24 having the above configuration, the sunlight 22 is collected by the concave mirror 26 and irradiated to the solar cell 16, so that a large photoelectric conversion output can be taken out even if the installation area of the solar cell 16 is small. it can. Similarly, since the sunlight 22 is condensed by the concave mirror 26 and applied to the heat utilization element 18 with respect to the heat utilization element 18, a large output can be taken out even if the heat utilization element 18 is small. Moreover, since the light 22a incident on the solar cell 16 is light from which infrared light has been removed by the cold filter 28, the temperature increase of the solar cell 16 can be suppressed and the decrease in light conversion output can be suppressed. Furthermore, since the infrared light 22b separated by the cold filter 28 is utilized by the heat utilization element 18, the energy utilization efficiency of the sunlight 22 can be enhanced. Further, since the sunlight 22 is condensed by the concave mirror 26 and then irradiated to the wavelength selection element 28, the wavelength is compared with the case where a wavelength selective reflection / transmission film is disposed on the surface of the solar cell as in the device described in Patent Document 4. The installation area of the selection element 28 can be reduced. Further, since the concave mirror 26 is used for condensing, the cost can be reduced as compared with the case using the condensing lens of Patent Document 3.

  In Embodiment 2, the mirror surface of the concave mirror 26 is a paraboloid, and the incident surface of the cold filter 28 is a hyperboloid. Instead, the mirror surface of the concave mirror 26 is spherical, although some aberrations occur. Alternatively, an elliptical surface may be used, and the incident surface shape of the cold filter 28 may be a spherical surface.

  In Embodiment 2, the shape of the incident surface of the cold filter 28 is a convex surface, but it may be a flat surface. However, the position B where the infrared light 22b reflected by the cold filter 28 is focused becomes a position away from the wavelength selection element 28 when the convex surface is provided, and the heat utilization element 18 may be arranged away from the wavelength selection element 28. Therefore, the heat utilization element 18 can be easily arranged.

  In the second embodiment, the wavelength selection element 28 is configured by a cold filter, but may be configured by a cold mirror. The transmittance characteristics of the cold mirror can be the same as in FIG. When the wavelength selection element 28 is formed of a cold mirror, the arrangement of the solar cell 16 and the heat utilization element 18 is interchanged in FIG.

<Example of Embodiment 2>
In the second embodiment, a cold filter having a characteristic of transmitting light (visible light) having a wavelength shorter than 700 nm and reflecting light (infrared light) of 700 nm or more is used. The temperature at the position B at which the infrared light 22b is focused reached 600 ° C. by the thermal energy generated by condensing the infrared light. The Stirling engine high-temperature portion is arranged as the heat utilization element 18 at the same position B to operate the Stirling engine, and the motor is driven by converting the reciprocating motion of the output piston of the Stirling engine into a rotational motion using a crank mechanism. A power generation output of about 0.9 mW was obtained. At this time, the surface temperature of the commercially available solar cell 16 arranged at the position A was 45 ° C., and a power generation output of 1.0 mW was obtained from the solar cell 16.

<Comparative example>
As a comparative example, the solar cell 16 used in the above example was directly irradiated without condensing sunlight. At this time, the surface temperature of the solar cell 16 was 65 ° C., and a power generation output of 0.1 mW was obtained from the solar cell 16.

According to the examples and comparative examples, the following can be said.
(A) Condensing the sunlight 22 with the concave mirror 26 and irradiating the solar cell 16 with a larger photoelectric conversion output than when irradiating the solar cell 16 with the same area without condensing the sunlight 22 It can be taken out.
(B) Since the light 22a incident on the solar cell 16 is light from which infrared light has been removed by the cold filter 28, the temperature rise of the solar cell 16 can be suppressed despite being condensed.
(C) Since the infrared light 22b separated by the cold filter 28 is used to drive the Stirling engine as the heat utilization element 18, the energy utilization efficiency of the sunlight 22 can be increased.

<< Embodiment 3 >>
A third embodiment of the light energy collecting device of the present invention is shown in FIG. This is because the concave mirror and the wavelength selection element are each configured in a semi-cylinder shape, and are arranged so as to extend in the same direction with a predetermined gap therebetween, and the solar cell and the heat utilization element are arranged in the extending direction of the half cylinder. They are arranged along each other. The same code | symbol is used for the part which is common in Embodiment 1,2. The light energy collecting device 30 includes a concave mirror 32, a wavelength selection element 34, a photoelectric conversion element 36, and a heat utilization element 38. The concave mirror 32 and the wavelength selection element 34 are each formed in a semi-cylindrical shape. The concave mirror 32 and the wavelength selection element 34 are arranged to extend in the same direction with a predetermined gap therebetween. FIG. 5B shows a cross section of the light energy collecting device 30 cut along a plane perpendicular to the extending direction of the concave mirror 32 and the wavelength selection element 34. The mirror surface shape of the concave mirror 32 in the same cross section is formed as a paraboloid. The shape of the incident surface of the wavelength selection element 34 in the same cross section is formed as a convex hyperboloid. The paraboloidal axial surface 20 ′ of the concave mirror 32 (the surface formed by aligning the parabolic axes in the extending direction of the half cylinder) and the hyperboloidal axial surface 20 ′ of the wavelength selection element 34 are in a position coincident with each other. . The axial surface 20 ′ is arranged in parallel or substantially parallel to the incident sunlight 22. The concave mirror 32 receives sunlight 22 and reflects and collects the sunlight 22 as it is. The condensed light forms a focal line at a focal point (a line formed by aligning the focal point of the parabola in the extending direction of the half cylinder) position A ′ of the concave mirror 32.

  The wavelength selection element 34 is disposed in the middle of the optical path from the concave mirror 32 to the focal line position A ′. In this embodiment, the wavelength selection element 34 is constituted by a cold mirror. The sunlight 22 reflected and condensed by the concave mirror 32 is incident on the cold mirror 34. The cold mirror 34 reflects the visible light 22a among the light of each wavelength region included in the incident sunlight 22, and transmits the infrared light 22b. The transmittance characteristic of the cold mirror 34 can be the same as that shown in FIG.

  The visible light 22a reflected by the cold mirror 34 forms a focal line at a position B 'on the axial surface 20' (a position near the surface of the concave mirror 32). The photoelectric conversion element 36 is arranged on the cold mirror 34 with the light receiving surface disposed at a right angle to the axial surface 20 ′ along the focal line position B ′ on the axial surface 20 ′ or in the vicinity thereof (a position where the visible light 22a can be received). It is arranged toward. The photoelectric conversion element 36 is configured by a solar cell (with solar cells arranged along the focal line position B ′). As the solar cell 36, a crystalline silicon solar cell, a GaAs-based compound solar cell, or the like that can obtain high conversion efficiency with respect to visible light is used. The visible light 22 a reflected by the cold mirror 34 is received by the solar cell 36. Thereby, the solar cell 36 generates photovoltaic power. The generated photovoltaic power is used for an appropriate power source.

  The heat utilization element 38 is disposed along the focal line position A ′ of the concave mirror 32 on the opposite side of the concave mirror 32 with the cold mirror 34 interposed therebetween or in the vicinity thereof (a position where the infrared light 22b can be received). The heat utilization element 38 is configured by a device that operates with thermal energy, such as a thermoelectric conversion element, a Stirling engine, or a water heater. The infrared light 22 b that has passed through the cold mirror 34 is received by the heat utilization element 38. Accordingly, the heat utilization element 38 generates power if it is a thermoelectric conversion element, rotates if it is a Stirling engine, and heats water if it is a water heater. The heat utilization element 38 is configured by a pipe laid along the focal line position A ′, a liquid such as water is supplied into the pipe, and a turbine is connected to the outlet side of the pipe, whereby the focal position A ′ is determined. Steam turbine power generation can also be performed with a liquid heated while passing.

  According to the light energy collecting device 30 having the above configuration, the sunlight 22 is collected by the concave mirror 32 and irradiated to the solar cell 36, so that a large photoelectric conversion output can be taken out even if the installation area of the solar cell 36 is small. it can. Similarly, since the sunlight 22 is condensed by the concave mirror 32 and irradiated to the heat utilization element 38 with respect to the heat utilization element 38, a large output can be taken out even if the heat utilization element 38 is small. Moreover, since the light 22a incident on the solar cell 36 is light from which infrared light has been removed by the cold mirror 34, the temperature increase of the solar cell 36 can be suppressed and the decrease in light conversion output can be suppressed. Furthermore, since the infrared light 22b separated by the cold mirror 34 is utilized by the heat utilization element 38, the energy utilization efficiency of the sunlight 22 can be enhanced. Further, since the sunlight 22 is condensed by the concave mirror 32 and then irradiated to the wavelength selection element 34, the wavelength is compared with a case where a wavelength selective reflection / transmission film is disposed on the surface of the solar cell as in the device described in Patent Document 4. The installation area of the selection element 34 can be reduced. Further, since the concave mirror 32 is used for condensing, the cost can be reduced as compared with that using the condensing lens of Patent Document 3.

  In Embodiment 3, the mirror surface shape of the concave mirror 32 is a paraboloid, and the incident surface shape of the cold mirror 34 is a hyperboloid, but instead, the mirror surface shape of the concave mirror 32 is a spherical surface although some aberrations occur. Alternatively, an elliptical surface may be used, and the incident surface shape of the cold mirror 34 may be a spherical surface.

  In the third embodiment, the shape of the incident surface of the cold mirror 34 is a convex surface, but it may be a flat surface. However, when the convex surface is used, the position B ′ where the visible light 22a reflected by the cold mirror 34 forms a focal line is a position away from the wavelength selection element 34, and the solar cell 36 may be arranged away from the wavelength selection element 34. Since it can do, arrangement | positioning of the solar cell 36 becomes easy.

  In the third embodiment, the wavelength selection element 34 is configured by a cold mirror, but may be configured by a cold filter. The transmittance characteristic of the cold filter can be the same as that shown in FIG. When the wavelength selection element 34 is formed of a cold mirror, the arrangement of the solar cell 36 and the heat utilization element 38 is exchanged in FIG.

<< Embodiment 4 >>
Embodiment 4 of the light energy collecting apparatus of the present invention is shown in FIG. This is a concave mirror made up of Fresnel mirrors. The same code | symbol is used for the part which is common in Embodiment 1-3. The light energy collecting device 40 includes a Fresnel concave mirror 42, a wavelength selection element 44, a photoelectric conversion element 16, and a heat utilization element 18. The Fresnel concave mirror 42 is composed of a Fresnel surface having a shape in which the mirror surface is arranged in a step shape with the paraboloid being cut into concentric circles. The parabolic axis 20 is arranged parallel or substantially parallel to the incident sunlight 22. As shown in FIG. 6B, the Fresnel concave mirror 42 has a circular shape as viewed from the direction of the shaft 20. The Fresnel concave mirror 42 receives sunlight 22 and reflects and collects the sunlight 22 as it is. The condensed light is focused on the focal position A of the Fresnel concave mirror 42.

  The wavelength selection element 44 is arranged in the middle of the optical path from the Fresnel concave mirror 42 to the focal position A of the Fresnel concave mirror 42. The wavelength selection element 44 is formed as a hyperboloid having a convex incident surface shape. The axis of the hyperboloid is arranged at the same position as the axis 20 of the Fresnel concave mirror 42. As shown in FIG. 6B, the wavelength selection element 44 has a circular shape as viewed from the direction of the axis 20. In this embodiment, the wavelength selection element 44 is constituted by a cold filter. The sunlight 22 reflected and condensed by the Fresnel concave mirror 42 enters a cold filter 44. The cold filter 44 transmits visible light 22a out of light in each wavelength region included in incident sunlight 22, and reflects infrared light 22b. The transmittance characteristic of the cold filter 44 can be the same as that shown in FIG.

  The photoelectric conversion element 16 is arranged at a focal position A of the Fresnel concave mirror 42 on the opposite side of the Fresnel concave mirror 42 with the cold filter 44 interposed therebetween or at a position near the focal position A (a position where the visible light 22a can be received). Then, it is arranged toward the cold filter 44. The photoelectric conversion element 16 is composed of a solar cell. As the solar cell 16, a crystalline silicon solar cell, a GaAs-based solar cell, or the like that can obtain high conversion efficiency with respect to visible light is used. The visible light 22 a that has passed through the cold filter 44 is received by the solar cell 16. Thereby, the solar cell 16 generates photovoltaic power. The generated photovoltaic power is used for an appropriate power source.

  The infrared light 22b reflected by the cold filter 44 is focused at a position B on the axis 20 (a position near the surface of the Fresnel concave mirror 42). The heat utilization element 18 is disposed at the focal position B on the shaft 20 or in the vicinity thereof (a position where the infrared light 22b can be received). The heat utilization element 18 is composed of a device that operates with thermal energy, such as a thermoelectric conversion element, a Stirling engine, or a water heater. The infrared light 22 b reflected by the cold filter 44 is received by the heat utilization element 18. Accordingly, the heat utilization element 18 generates power if it is a thermoelectric conversion element, rotates if it is a Stirling engine, and heats water if it is a water heater.

  According to the light energy collecting device 40 having the above configuration, the sunlight 22 is collected by the Fresnel concave mirror 42 and irradiated to the solar cell 16, so that a large photoelectric conversion output can be taken out even if the installation area of the solar cell 16 is small. Can do. Similarly, since the sunlight 22 is condensed by the Fresnel concave mirror 42 and irradiated to the heat utilization element 18 with respect to the heat utilization element 18, a large output can be taken out even if the heat utilization element 18 is small. And since the light 22a which injects into the solar cell 16 is the light which removed the infrared light with the cold filter 44, the temperature rise of the solar cell 16 can be suppressed and the fall of a light conversion output can be suppressed. Furthermore, since the infrared light 22b separated by the cold filter 44 is used by the heat utilization element 18, the utilization efficiency of the energy of the sunlight 22 can be increased. Further, since the sunlight 22 is condensed by the Fresnel concave mirror 42 and then irradiated to the wavelength selection element 44, compared to the case where a wavelength selective reflection / transmission film is disposed on the surface of the solar cell as in the device described in Patent Document 4. The installation area of the wavelength selection element 44 can be reduced. Further, since the Fresnel concave mirror 42 is used for condensing, it is possible to reduce the cost as compared with that using the condensing lens of Patent Document 3.

  Further, according to the light energy collecting device 40 of FIG. 6, the following effects can be obtained as compared with the light energy collecting device 24 of the second embodiment of FIG. FIG. 7 shows a comparison between the light energy collecting device 24 of FIG. 4 and the light energy collecting device 40 of FIG. 6 with concave mirrors 26 and 42 having the same diameter. According to this, since the light energy collecting device 40 collects the sunlight 22 with the flat Fresnel concave mirror 42, the wavelength selection element 44 can be formed in a small area (small diameter) compared to the light energy collecting device 24, and as a result, The area of sunlight 22 that can be used is widened, and a high light collecting ability is obtained. Further, since the Fresnel concave mirror 42 has a flat plate shape, it can be easily installed. Further, the Fresnel shape of the Fresnel concave mirror 42 can be molded, and the wavelength selection element 44 can be formed in a small area (small diameter), so that the manufacturing cost can be reduced.

  In the fourth embodiment, the mirror surface shape of the Fresnel concave mirror 42 is a paraboloid, and the incident surface shape of the cold filter 44 is a hyperboloid. Instead, although some aberrations occur, the mirror surface shape of the Fresnel concave mirror 42 is used. Can be a spherical surface or an elliptical surface, and the incident surface shape of the cold filter 44 can be a spherical surface.

  In the fourth embodiment, the convex shape of the incident surface of the cold filter 44 is configured as a continuous surface, but may be configured as a Fresnel surface. That is, the substrate of the cold filter 44 is formed in a flat plate shape like the Fresnel concave mirror 42, and its incident surface (opposite surface to the Fresnel concave mirror 42) is formed by a hyperboloid, a spherical Fresnel surface, etc. An optical multilayer film constituting a cold filter is formed. As a result, the infrared light 22b reflected by the cold filter 44 is focused on the position B, and most of the visible light 22a transmitted through the cold filter 44 goes straight as it is and is focused on the position A. It should be noted that the wavelength selection elements 14 and 28 of the first embodiment (FIG. 1) and the second embodiment (FIG. 4) can also be configured by a Fresnel surface instead of the convex shape of the incident surface. Similarly, in the third embodiment (FIG. 5), the substrates of the semi-cylindrical concave mirror 32 and the semi-cylindrical wavelength selection element 34 are respectively configured in a flat plate shape, and the concave shape of the mirror surface of the semi-cylindrical concave mirror 32 is replaced with a continuous surface. Fresnel surface (Fresnel surface in which fresnel fringes extend linearly in the axial direction of the cylinder), and the convex shape of the incident surface of the semi-cylindrical wavelength selection element 34 is replaced with a continuous surface. It is also possible to configure the fringe with a fresnel surface extending linearly in the axial direction of the cylinder.

  In the fourth embodiment, the incident surface shape of the cold filter 44 is a convex surface, but it may be a flat surface (not a Fresnel surface but a continuous surface). However, the position B where the infrared light 22b reflected by the cold filter 44 is focused becomes a position away from the wavelength selection element 44 when the convex surface is provided, and the heat utilization element 18 may be arranged away from the wavelength selection element 44. Therefore, the heat utilization element 18 can be easily arranged.

  In the fourth embodiment, the wavelength selection element 44 is configured by a cold filter, but may be configured by a cold mirror. The transmittance characteristics of the cold mirror can be the same as in FIG. When the wavelength selection element 44 is formed of a cold mirror, the arrangement of the solar cell 16 and the heat utilization element 18 is interchanged in FIG.

  Moreover, although each said embodiment demonstrated the case where sunlight was used as the light from the light source containing infrared light and visible light, light other than sunlight can also be used. For example, in a system that drives an artificial light source at night using power stored by solar power generation in the daytime, light from the artificial light source can be used as a light source of the light energy collecting device of the present invention to regenerate power.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows Embodiment 1 of the optical energy collection device of this invention, (a) is sectional drawing cut | disconnected by the plane which passes along the axis | shaft 20 of the concave mirror 12 (XX sectional view taken on the line of (b)), (b ) Is a plan view (viewed from the direction of the axis 20). It is a diagram which shows an example of the transmittance | permeability characteristic of the cold mirror 14 of FIG. It is a diagram which shows an example of the transmittance | permeability characteristic of a cold filter at the time of replacing the cold mirror 14 of FIG. 1 with a cold filter. It is a figure which shows Embodiment 2 of the optical energy collection device of this invention, (a) is sectional drawing cut | disconnected by the plane which passes along the axis | shaft 20 of the concave mirror 26 (YY arrow sectional drawing of (b)), (b) ) Is a plan view (viewed from the direction of the axis 20). FIG. 5 is a diagram showing a third embodiment of the optical energy collecting device of the present invention, where (a) is a perspective view, and (b) is a diagram illustrating the optical energy collecting device 30 perpendicular to the extending direction of the concave mirror 32 and the half cylinder of the wavelength selection element 34. It is sectional drawing cut | disconnected by the flat plane. FIG. 6 is a diagram showing a light energy collecting device according to a fourth embodiment of the present invention, in which (a) is a cross-sectional view cut along a plane passing through the axis 20 of the Fresnel concave mirror 42 (a cross-sectional view taken along the line ZZ in (b)); b) is a plan view (viewed from the direction of the axis 20). 4 is a diagram showing the light energy collecting device 24 of FIG. 4 and the light energy collecting device 40 of FIG. 6 in comparison with the concave mirrors 26 and 42 having the same diameter, and a cross section cut along a plane passing through the axis of the collecting mirror. FIG.

Explanation of symbols

  10, 24, 30, 40 ... optical energy collecting device, 12, 26, 32 ... concave mirror (concave mirror in which the concave surface is a continuous surface), 14, 34 ... cold mirror (wavelength selection element), 16, 36 ... photoelectric Conversion element, 18, 38 ... Heat utilization element, 22 ... Sunlight (light from a light source including infrared light and visible light), 28, 44 ... Cold filter (wavelength selection element), 42 ... Concave mirror (concave surface is Fresnel surface) Concave mirror made up of

Claims (10)

A concave mirror that reflects and collects light from a light source including infrared light and visible light;
A wavelength selection element that enters the collected light and separates visible light and infrared light contained in the light;
A photoelectric conversion element that receives the separated visible light and generates photovoltaic power; and
A light energy collecting apparatus comprising: a heat utilization element that receives the separated infrared light and uses the thermal energy of the infrared light. The wavelength selection element is a cold mirror that reflects visible light and transmits infrared light;
The photoelectric conversion element receives visible light reflected by the cold mirror,
The light energy collecting apparatus according to claim 1, wherein the heat utilization element receives infrared light transmitted through the cold mirror. The wavelength selection element is a cold filter that transmits visible light and reflects infrared light;
The photoelectric conversion element receives visible light transmitted through the cold filter,
The light energy collecting apparatus according to claim 1, wherein the heat utilization element receives infrared light reflected by the cold filter.   The light energy collecting device according to any one of claims 1 to 3, wherein a mirror surface shape of the concave mirror is any one of a paraboloid, a spherical surface, and an ellipsoid.   The light energy collection device according to claim 1, wherein an incident surface shape of the wavelength selection element is a convex surface or a flat surface.   The light energy collecting device according to claim 5, wherein the convex surface is a hyperboloid or a spherical surface.   The optical energy collection device according to any one of claims 1 to 3, wherein a mirror surface shape of the concave mirror is a semi-cylindrical concave surface, and the wavelength selection element is a semi-cylindrical convex surface or a flat surface.   The optical energy collection device according to any one of claims 5 to 7, wherein the convex surface or the semi-cylindrical convex surface of the wavelength selection element is configured by a continuous surface or a Fresnel surface.   The optical energy collection device according to any one of claims 1 to 8, wherein the concave surface of the concave mirror is configured as a continuous surface or a Fresnel surface.   The light energy collecting device according to any one of claims 1 to 9, wherein the heat utilization element is any one of a thermoelectric conversion element, a Stirling engine, a water heater, and a steam turbine generator.

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