JP6653918B2 - Thermophotovoltaic power generation device and thermophotovoltaic power generation system - Google Patents

Description

  The present invention has a flat radiating portion provided with a heat radiation light source that converts heat into radiant light, which is provided to be heat conductive to a heat supply portion that receives supply of heat from a heat source, and receives radiant light. The present invention relates to a thermo-photovoltaic power generation device comprising: a flat photoelectric conversion unit having a photoelectric conversion element for generating power; and a photoelectric conversion unit provided in addition to the radiation unit in a state where the photoelectric conversion element is opposed to a heat radiation light source.

  In general, when an object is heated, light having a spectrum corresponding to the material constituting the object and the temperature of the object, that is, radiation light is generated. A device that captures the radiated light with a solar cell and generates power is referred to as a thermophotovoltaic (TPV) device (Patent Document 1).

This thermophotovoltaic device includes a heat radiation light source that emits (radiates) radiation light containing a specific wavelength more, a heat supply unit that supplies heat from the heat source to the heat radiation light source, and a photoelectric conversion element. And a photoelectric conversion unit.
The heat radiation light source is configured such that one of the base materials made of, for example, a plate-like metal material is used as a heat absorbing surface and the other is used as a radiation surface.
The heat supply unit is disposed in contact with and in contact with the heat absorbing surface of the heat radiation light source. The photoelectric conversion unit is arranged on a side opposite to the heat supply unit with the heat radiation light source interposed therebetween, facing the radiation surface. That is, the photoelectric conversion unit is arranged to face the heat supply unit.

JP 2014-217110 A

In such a thermophotovoltaic device, the heat supply unit and the heat absorption surface of the heat radiation light source are disposed in contact with each other so that the area of the heat radiation light source cannot be arbitrarily increased. Further, depending on the type of the heat radiation light source (for example, in the case of a light transmissive material), radiation light having a wavelength that cannot be converted by the photoelectric conversion element of the photoelectric conversion unit leaks from the heat supply unit, and the power is generated by the photoelectric conversion unit. Loss without contributing. In this case, the photoelectric conversion unit is heated by radiation having a wavelength that cannot be converted by the photoelectric conversion element of the photoelectric conversion unit, and the power generation efficiency is further reduced.
Furthermore, even when a photoelectric conversion element receives radiation light from a thermal radiation light source, it cannot normally generate electricity by photoelectrically converting all of the received radiation light. As a result, the power generation efficiency is reduced.
Therefore, a thermoelectric generator having high power generation efficiency without lowering the power generation efficiency is desired.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thermoelectric generator having high power generation efficiency.

The characteristic configuration of the thermophotovoltaic device according to the present invention for achieving the above object is as follows.
A flat radiating section provided with a heat radiation light source that converts heat into radiation light, a heat supply section that supplies heat supplied from the heat source to the radiation section, and a photoelectric conversion element that receives the radiation light and generates power. And a flat-panel photoelectric conversion unit with
The radiating portion is erected on the heat supply portion so as to be able to conduct heat from the heat supply portion,
The photoelectric conversion unit is provided along with the radiation unit in a state where the photoelectric conversion element is opposed to the heat radiation light source,
A cooling unit that cools the photoelectric conversion unit,
The photoelectric conversion unit is erected on the cooling unit,
The said photoelectric conversion element is in the point connected so that heat conduction to the said cooling part is possible.

Normally, the surface of the heat supply unit also functions as a radiation surface according to the material and temperature, and emits radiation light that is not controlled to a specific wavelength distribution. Uncontrolled radiation from the heat supply unit may be transmitted through the radiation unit even when the radiation unit covers the heat supply unit. For example, when the radiating portion includes a material that can transmit infrared light, such as an infrared transparent substrate such as an infrared transparent glass, uncontrolled radiation from the heat supply portion easily transmits through the radiating portion.
When the heat supply unit emits radiant light, for example, as a surface light source, the radiant light from the heat supply unit is incident at a right angle on a surface provided in parallel with the radiation surface of the heat supply unit, and has a maximum density. The radiation of the heat supply unit is radiated.
However, according to the above configuration, since the photoelectric conversion unit is provided side by side with the radiating unit erected on the heat supply unit, it is possible to avoid an arrangement parallel to the surface of the heat supply unit. The radiation from the heat supply unit does not enter at right angles. In particular, when the radiating section is provided vertically on the heat supply section, and the photoelectric conversion section and the radiated light from the heat supply section are parallel, it is possible to prevent the radiated light from being incident on the photoelectric conversion section. . That is, the density of the radiant light from the heat supply unit received by the photoelectric conversion unit can be reduced, and the photoelectric conversion element is configured to avoid heat generation due to the radiant light from the heat supply unit.

In this case, the photoelectric conversion element receives radiation light from the radiating section to generate power, but the photoelectric conversion section also generates heat due to radiation light from the radiating section. For example, when light having a wavelength shorter than the band gap energy of the photoelectric conversion element is received by the photoelectric conversion element, heat is generated by relaxation within the band.
However, the photoelectric conversion element capable of conducting heat to the cooling unit can release the heat generated by the radiation light from the radiation unit to the cooling unit. Therefore, power can be generated while the photoelectric conversion unit is maintained at a high power generation efficiency temperature.

  Therefore, according to the above configuration, it is possible to avoid the heat generation due to the radiation light from the heat supply unit of the photoelectric conversion element, and further maintain the photoelectric conversion element at a desired temperature while releasing the heat generation due to the radiation light from the radiation unit. Thus, a decrease in the conversion efficiency of the photoelectric conversion element can be avoided, and a thermoelectric power generation device with high power generation efficiency can be provided.

Further characteristic configuration of the thermophotovoltaic device according to the present invention,
The photoelectric conversion unit is a photoelectric conversion element having a photoelectric conversion surface on both surfaces.

According to the above configuration, since the photoelectric conversion unit can receive radiation light from the radiation unit on both surfaces on the flat plate, relatively large power can be obtained even in the same space.
In addition, a part of the radiation light from the radiation part received by the photoelectric conversion element is transmitted through the photoelectric conversion element, but a part of the radiation light from the radiation part is provided on one surface of the photoelectric conversion part. Also, when the light passes through the photoelectric conversion element, it is absorbed by the radiating part provided in parallel with the photoelectric conversion part. Therefore, light that cannot be used in the photoelectric conversion element can be reused.
Therefore, it is possible to avoid a decrease in power generation efficiency and to provide a thermoelectric power generation device with high power generation efficiency.

Further characteristic configuration of the thermophotovoltaic device according to the present invention,
The radiator includes an infrared transparent substrate formed of a material that can transmit infrared light in a flat plate shape,
The infrared transparent substrate is provided with a heat-light conversion element for radiating radiation having a predetermined wavelength amplified as the heat radiation light source in a flat plate portion, and is connected to the heat supply portion so as to be able to conduct heat from the heat supply portion. In that it is.

The so-called infrared transparent substrate has almost no absorption of light in the infrared region. Therefore, the infrared transparent substrate hardly emits radiation in the infrared region.
That is, according to the above configuration, the infrared transparent substrate that emits almost no radiant light, up to a heat-light conversion element that radiates radiant light having a predetermined wavelength amplified, without losing heat energy with uncontrolled radiation. In addition, heat can be supplied from the heat supply unit by heat transfer, and radiation having a predetermined wavelength amplified can be emitted as radiation.
Therefore, it is possible to provide a thermoelectric generator having high power generation efficiency.

Further characteristic configuration of the thermophotovoltaic device according to the present invention,
The radiation part and the photoelectric conversion part are provided alternately.

  According to the above configuration, the radiating portion and the photoelectric conversion portion can be arranged in a small space at a high density, so that a thermoelectric power generation device with high power generation efficiency can be provided compactly.

Further characteristic configuration of the thermophotovoltaic device according to the present invention,
The present invention is characterized in that a shielding unit for shielding radiation light from the supply unit is provided between the heat supply unit and the photoelectric conversion unit.

  According to the above configuration, since uncontrolled radiation from the heat supply unit can be prevented from being supplied to the photoelectric conversion unit, the photoelectric conversion unit is not heated, and a decrease in power generation efficiency can be avoided. A thermophotovoltaic device can be provided.

Further characteristic configuration of the thermophotovoltaic device according to the present invention,
The shielding portion is a heat insulating material, and the heat insulating material is provided so as to cover the heat supply portion.

According to the above configuration, the heat supply unit is covered with the heat insulating material and kept warm.
Therefore, the radiation of uncontrolled radiation from the heat supply unit is suppressed, the loss of heat energy is avoided, and the photoelectric conversion unit can avoid heating and avoid a decrease in power generation efficiency. A photovoltaic device can be provided.

Further characteristic configuration of the thermophotovoltaic device according to the present invention,
The shielding unit is a light reflector that reflects light, and the light reflector is provided to reflect light toward the heat supply unit.

According to the above configuration, the radiation from the heat supply unit is returned to the heat supply unit again by the light reflector.
Therefore, the radiation of uncontrolled radiation from the heat supply unit is suppressed, the loss of heat energy is avoided, and the photoelectric conversion unit can avoid heating and avoid a decrease in power generation efficiency. A photovoltaic device can be provided.

The characteristic configuration of the thermophotovoltaic power generation system including the thermophotovoltaic power generation device according to the present invention includes
The thermophotovoltaic device is provided in a vacuum vessel.

According to the above configuration, it is possible to prevent the heat supply unit from being convected by the atmospheric gas such as the atmosphere or to prevent the photoelectric conversion unit from being heated. Therefore, it is possible to provide a thermoelectric power generation system with high power generation efficiency.

Sectional drawing which shows the whole structure of a thermophotovoltaic device and a thermophotovoltaic power generation system Schematic diagram of another cross section showing the entire structure of the thermophotovoltaic device and the thermophotovoltaic system Diagram showing an example of a thermo-optical conversion element The figure which shows an example of the spectral radiance of a thermo-optical conversion element The figure explaining an example of the conversion efficiency of the energy of the thermophotovoltaic device The figure which shows another whole structure of a thermophotovoltaic device and a thermophotovoltaic power generation system FIG. 4 illustrates an example of a power generation density of a photoelectric conversion unit.

  With reference to FIG. 1 and FIG. 2, a thermophotovoltaic power generation device 100 and a thermophotovoltaic power generation system 1 according to an embodiment of the present invention will be described.

The thermo-photovoltaic power generation device 100 according to the present embodiment includes a flat radiator 10 having a thermo-optical conversion element 12 as a heat radiation source for converting heat into radiant light, and a radiator 10 that receives heat supplied from the heat source. And a flat plate-like photoelectric conversion unit 30 including a photoelectric conversion element 31 that receives radiant light and generates power.
Further, a cooling unit 40 that cools the photoelectric conversion unit 30 is provided.

  In the case of this example, the heat source of the heat supplied to the heat supply unit 20 may be, for example, exhaust heat of a gas engine or a heat source that condenses sunlight. Of course, other heat sources are available and are not limited to a particular heat source. The outer peripheral portion of the heat supply unit 20 is formed of, for example, a metal having high thermal conductivity such as iron, copper, and stainless steel. In this example, it is formed of stainless steel.

Then, the thermophotovoltaic device 100 is stored in the vacuum space 60 of the cooling unit 40 also serving as the vacuum container 61.
In this example, the space 60 is kept at a vacuum of about 0.01 mPa to 1 kPa.

In this example, the radiating section 10 is provided upright with respect to the heat supply section 20 in the vertical direction of the heat supply section 20 in FIGS. 1 and 2. In the present example, the radiation section 10 is provided at right angles to the surface of the heat supply section 20.
In addition, the photoelectric conversion unit 30 is erected on the cooling unit 40 in a direction opposite to the installation direction of the heat supply unit 20 which is opposed to the photoelectric conversion unit 30. In this example, the photoelectric conversion unit 30 is provided at right angles to the cooling unit 40.
FIG. 2 is a schematic cross-sectional view of another cross section orthogonal to the cross section of the thermoelectric power generation system 1 shown in FIG. FIG. 2 illustrates the radiation section 10 and the photoelectric conversion section 30 on the same cross section for convenience to schematically show the relationship among the radiation section 10, the heat supply section 20, the photoelectric conversion section 30, and the cooling section 40. I have.

Therefore, the radiation section 10 and the photoelectric conversion section 30 are provided in parallel. Further, the photoelectric conversion unit 30 is provided in a direction orthogonal to the surface of the heat supply unit 20.
Therefore, most of the uncontrolled radiation from the surface of the heat supply unit 20 is emitted in parallel to the photoelectric conversion unit 30, and the photoelectric conversion unit 30 is not controlled from the surface of the heat supply unit 20. Heating by radiation light can be avoided.

  Further, the radiation section 10 and the photoelectric conversion section 30 are provided at a predetermined interval. The radiation section 10 and the photoelectric conversion section 30 do not physically contact each other. Therefore, the radiation section 10 and the photoelectric conversion section 30 are thermally isolated from each other.

  Further, the radiation section 10 and the cooling section 40 are provided at a predetermined interval. The radiation section 10 and the cooling section 40 do not physically contact each other. Therefore, the radiation section 10 and the cooling section 40 are thermally isolated.

  Further, the photoelectric conversion unit 30 and the heat supply unit 20 are provided at a predetermined interval. There is no physical contact between the photoelectric conversion unit 30 and the heat supply unit 20. Therefore, the photoelectric conversion unit 30 and the heat supply unit 20 are thermally isolated from each other.

In this example, as shown in FIGS. 1 and 2, a case is illustrated in which a rectangular flat radiating portion 10 and a rectangular flat flat photoelectric conversion portion 30 corresponding to the radiating portion 10 are arranged in a space 60 having a rectangular cross section. However, these exemplifications are for convenience of explanation and are not limited to these shapes.
Hereinafter, the thermo-optical power generation device 100 and the thermo-optical power generation system 1 will be described in more detail.

  The radiating section 10 includes an infrared transparent substrate 11 for transferring heat from the heat supplying section 20 and supplying the heat to the thermo-optical conversion element 12. That is, the radiation section 10 includes the infrared transparent substrate 11 and the thermo-optical conversion element 12.

  The radiating section 10 is preferably formed to have a height from a heat source of 10 to 100 mm. In consideration of the relationship with the photoelectric conversion unit 30 described later, it is particularly preferably 10 mm to 40 mm. If the radiation part 10 is too small, it is economically disadvantageous. If the radiating section 10 is too large, heat transfer from the heat supply section 20 is not sufficient, which is also disadvantageous economically.

The infrared transparent substrate 11 is a material that can transmit infrared light. In this example, the infrared transparent substrate 11 is formed in a flat plate shape.
Examples of the infrared transparent substrate 11 include magnesium oxide, silicon oxide, silicon silicon carbide (SiC), diamond, sapphire, aluminum nitride, gallium nitride, calcium fluoride, magnesium fluoride, zinc selenium, barium fluoride, and zirconium oxide. , Hafnium oxide, titanium oxide, yttria oxide, or the like can be used.
In this example, sapphire is used as the infrared transparent substrate 11.

The infrared transparent substrate 11 stands on the heat supply unit 20. The infrared transparent substrate 11 and the heat supply unit 20 are thermally connected to each other so as to be able to conduct heat.
The infrared transparent substrate 11 functions as a support for supporting the thermo-optical conversion element 12. The infrared transparent substrate 11 and the thermo-optical conversion element 12 are thermally connected to each other so as to be able to conduct heat.
In this example, the infrared transparent substrate 11 is fixed by pressing one side of the infrared transparent substrate 11 into a narrow groove provided on the surface of the heat supply unit 20.
Therefore, the heat supply unit 20 and the thermo-optical conversion element 12 are formed so as to be able to conduct heat via the infrared transparent substrate 11.

In this example, the infrared transparent substrate 11 includes a thermo-optical conversion element 12 that emits radiation light having a predetermined wavelength amplified in a flat plate portion.
Materials and members suitable for use as the thermo-optical conversion element 12 include metals such as tantalum and tungsten; semiconductors such as silicon silicon carbide; other insulators; Can be used. As a member in which radiation is controlled by processing a semiconductor or an insulator such as a periodic structure, a photonic crystal, which will be described later, is particularly suitable.

A so-called photonic crystal having a predetermined optical structure can be used for the thermo-optical conversion element 12 of the present example. Then, the thermo-optical conversion element 12 has a function of converting the supplied heat into radiation light including a wavelength corresponding to the optical structure as a photonic crystal.
The thermo-optical conversion element 12 includes, for example, a refraction portion 13 made of a semiconductor and an optical substrate 14 having a smaller light refractive index than the semiconductor of the refraction portion 13. The thermo-optical conversion element 12 of this example receives thermal energy from the infrared transparent substrate 11 by heat transfer.

The thermo-optical conversion element 12 includes a configuration in which the refraction portions 13 are arranged in a square lattice on one surface of an optical substrate 14 configured in a plate shape in a direction in which radiation light is to be emitted.
The arrangement of the refraction portions 13 is not limited to a square lattice.
Therefore, the surface provided with the refraction portion 13 is oriented to emit mainly radiated light, and the surface on the other side is a surface which emits radiation light having a slightly lower intensity than the surface provided with the refraction portion 13. That is, the intensity is slightly biased toward the surface of the optical substrate 14 on which the refraction portion 13 is provided, and the radiated light is emitted from both surfaces of the optical substrate 14.

In the case of this example, the infrared transparent substrate 11 transmits the radiation light radiated from both sides of the optical substrate 14. Therefore, radiation light is emitted from both sides of the radiation section 10.
The arrangement of the refraction portions 13 is not limited to a square lattice. Other arrangements and arrangements, including for example a triangular staggered grid, may also be included.
Further, the refraction portion 13 and the optical substrate 14 constituting the thermo-optical conversion element 12 are not limited to the two-dimensional arrangement and arrangement, but may include a three-dimensional arrangement and arrangement.

The bending portion 13 is formed of a semiconductor. Semiconductors include intrinsic semiconductors.
In this example, the refraction portion 13 is formed of a crystal of Si.
As a semiconductor that can be used as the refraction portion 13, SiC can be suitably used in addition to the Si crystal. Note that Si and SiC are intrinsic semiconductors.

In this example, the refraction portion 13 is formed in a columnar shape so as to project on the optical substrate 14. In this example, a case is shown in which the thermo-optical conversion element 12 is a single optical substrate 14 provided with a refraction portion 13.
As an example, the diameter d of the refraction portion 13 is approximately 200 nm. The height h of the refraction part 13 is about 500 nm. The refraction portions 13 are arranged in a square lattice shape, and the period length a (distance between centers of adjacent refraction portions 13) of the square lattice is about 600 nm.

The optical substrate 14 is a substrate capable of transmitting light having a wavelength included in visible light to far infrared light. In other words, the substrate has no absorptivity in the visible to far infrared region.
The optical substrate 14 is formed of a material that can transmit light having a wavelength included in visible light to far infrared light.

In this example, the optical substrate 14 is an infrared transparent substrate in this example. Specifically, sapphire is used. In this example, the optical substrate 14 is formed integrally with the infrared transparent substrate 11.
Examples of the material that can transmit light having a wavelength included in the range from visible light to far infrared light used for the optical substrate 14 include, for example, magnesium oxide, silicon oxide, SiC, diamond, sapphire, aluminum nitride, gallium nitride, calcium fluoride, and the like. Magnesium fluoride, zinc selenium, barium fluoride, zirconium oxide, hafnium oxide, titanium oxide, yttria oxide, and the like can also be suitably used.

The cooling unit 40 is a member that receives heat supplied from the photoelectric conversion unit 30, does not accumulate heat, and discharges the heat to the outside of the system. That is, it is a member that cools the photoelectric conversion unit 30.
The cooling unit 40 can exhibit its function by cooling by a known cooling method. In this example, the cooling unit 40 is configured such that cooling water flows through an outer wall (container) made of stainless steel. The cooling unit 40 is not limited to this exemplary embodiment, and may include other systems and modes having the same function.

The photoelectric conversion unit 30 is a member including a photoelectric conversion element 31 that converts received light into electricity.
In this example, a photoelectric conversion element 31 that can receive light on both sides and generate power on both sides is used.
That is, the photoelectric conversion unit 30 can receive the radiated light from the radiating unit 10 on both surfaces to generate power.

The photoelectric conversion unit 30 is erected on a cooling unit 40 that cools the photoelectric conversion unit 30, and the photoelectric conversion element 31 is connected to the cooling unit 40 so as to be able to conduct heat.
Further, the photoelectric conversion unit 30 is provided along with the radiation unit 10 while being supported by the cooling unit 40.
Further, the photoelectric conversion unit 30 is provided in parallel with the radiation unit 10. The photoelectric conversion unit 30 and the heat supply unit 20 are thermally isolated from each other.

The photoelectric conversion unit 30 is provided along with the radiating unit 10 in a state where the photoelectric conversion element 31 is opposed to the radiation surface of the thermo-optical conversion element 12 formed of a plane.
The photoelectric conversion unit 30 is provided so as to be able to receive the radiation light radiated by the thermo-optical conversion element 12.
In this example, the photoelectric conversion element 31 of the photoelectric conversion unit 30 is connected to the cooling unit 40 in a heat conductive state, is provided upright on the cooling unit 40, and is provided in parallel with the radiating unit 10. ing.

  Since the photoelectric conversion unit 30 uses the photoelectric conversion element 31 that can receive light on both sides and generate power on both sides, of the light emitted from the thermo-optical conversion element 12, the wavelength equal to or smaller than the band gap energy of the photoelectric conversion element 31 is used. Of light. By opposing the photoelectric conversion units 30 and the thermo-optical conversion elements 12 alternately and side-by-side, of the light emitted from the thermo-optical conversion elements 12, the light transmitted through the photoelectric conversion elements is adjacent to the photoelectric conversion elements 31 with the photoelectric conversion elements 31 interposed therebetween. It is absorbed by the thermo-optical conversion element 12. Therefore, light that cannot be used by the photoelectric conversion element 31 can be reused, and the efficiency of the thermo-optical power generation device 100 improves.

The photoelectric conversion element 31 and the cooling unit 40 are thermally connected. Therefore, the photoelectric conversion unit 30 does not separately include a member having a function of receiving heat from the photoelectric conversion element 31 and transferring the heat to the cooling unit 40.
Specifically, the photoelectric conversion element 31 and the cooling unit 40 are connected in direct contact with each other in a state where heat conduction is possible. In this example, one end of the photoelectric conversion element 31 is press-fitted and fixed to a slit provided on the surface of the cooling unit 40.

  The photoelectric conversion unit 30 to the photoelectric conversion element 31 may be formed to have a height from the cooling unit of 10 to 100 mm, and in this example, may be formed in a plate shape of about 10 mm to 40 mm square. If the photoelectric conversion unit 30 is too small, it is economically disadvantageous. If the photoelectric conversion unit 30 is too large, heat transfer to the cooling unit 40 is not sufficient, and the temperature of the photoelectric conversion unit rises, which is disadvantageous because the efficiency of photoelectric conversion, that is, the power generation efficiency is reduced.

The photoelectric conversion element 31 is a member that converts light into electricity.
As the photoelectric conversion element 31, for example, a general solar cell can be used. For example, a silicon solar cell, a gallium antimony solar cell, a germanium solar cell, or an indium gallium arsenide solar cell can be used. Of course, the specific mode of the photoelectric conversion element 31 is not limited to these examples.

When receiving and generating power, these solar cells generate heat due to relaxation in the band. Therefore, the cooling unit 40 directly cools the solar cell used as the photoelectric conversion element 31 by heat conduction, so that it is possible to avoid a decrease in power generation efficiency due to a high temperature of the solar cell.
When these solar cells receive light of a long wavelength, they absorb the light and generate heat. Therefore, by cooling the solar cell used as the photoelectric conversion element 31 by the cooling unit 40, it is possible to avoid that the solar cell becomes hot and the power generation efficiency is reduced.

The photoelectric conversion unit 30 and the photoelectric conversion element 31 will be supplemented.
The photoelectric conversion unit 30 is a photoelectric conversion element 31, and each surface of the photoelectric conversion element 31 functions as a planar functional unit having a photoelectric conversion function. That is, the photoelectric conversion unit 30 is a photoelectric conversion element 31 having a photoelectric conversion surface on both surfaces.

The relationship between the radiating unit 10 and the photoelectric conversion unit 30 will be supplemented.
In this example, the radiating unit 10 and the photoelectric conversion unit 30 are alternately arranged in the longitudinal direction of the heat supply unit 20 and are provided side by side.
Accordingly, the photoelectric conversion elements 31 provided on both sides of the radiating section 10 receive the radiated light emitted from both sides of the radiating section 10, respectively, and generate electric power.
In addition, the radiating section 10 and the photoelectric conversion section 30 are provided side by side so as to be alternately repeated, so that the radiating section 10 having a larger area with respect to the surface area of the heat supply section 20, that is, the thermo-optical conversion element 12. By providing it, heat energy can be efficiently converted to radiant light.
Supplementally, in this example, since more radiating sections 10 can be provided on the surface of the heat supplying section 20, more of the heat energy of the heat supplied from the heat source to the heat supplying section 20 is transferred to the radiating section. It is possible to reduce the energy which is converted into the controlled radiation from the heat supply unit 10 and is relatively converted into the uncontrolled radiation from the heat supply unit 20.

It is necessary that the wavelength suitable for power generation of the photoelectric conversion element 31 and the emission spectrum of the radiation of the thermo-optical conversion element 12 have a main part that matches each other and are in a suitable combination.
For example, when a silicon solar cell is used as the thermo-optical conversion element 12, it is preferable that the peak of the wavelength of the emission spectrum of the photoelectric conversion element 31 be less than 1120 nm. This is because silicon solar cells generally cannot photoelectrically convert light having a wavelength exceeding 1120 nm. Even when other solar cells are used, the peak of the wavelength of the emission spectrum of the photoelectric conversion element 31 can be similarly determined.

The relationship between the thermo-optical conversion element 12 and the photoelectric conversion element 31 will be supplemented.
The members exemplified above as suitable materials for use as the thermo-light conversion element 12 have a sharper wavelength spectrum than a so-called black body, in which a predetermined wavelength of radiated light is amplified. By combining with the element 31, high power generation efficiency can be obtained.
Here, the power generation efficiency refers to a ratio of the energy converted into electricity in the input thermal energy.

FIG. 4 shows the wavelength spectrum (line BB in FIG. 4) of the radiation of the black body (material is SiC) at 1000 ° C. and the thermo-optical conversion using the photonic crystal exemplified in this example at 1000 ° C. 4 illustrates a wavelength spectrum of radiation (line EM in FIG. 4) in the case of the element 12. In FIG. 4, “SP” indicates spectral radiance.
In the case of the thermo-optical conversion element 12 using the photonic crystal illustrated in this example, the wavelength spectrum of the radiation is extremely sharp, and it can be seen that the thermo-optical conversion element 12 has particularly preferable characteristics as a thermal radiation light source.

FIG. 5 shows the power generation efficiency when the radiant light of the thermo-optical conversion element 12 using the photonic crystal exemplified in this example at 1000 ° C. is received by a silicon solar cell to generate power. In FIG. 5, “Ef” on the vertical axis of the graph indicates efficiency. In FIG. 5, “E” on the horizontal axis of the graph indicates voltage.
In this example, it can be seen that a conversion efficiency as high as 68% is exhibited at a release voltage of about 0.8 V suitable for a silicon solar cell.

In FIG. 7, when the photoelectric conversion element 31 is a silicon solar cell, the radiant light when the thermo-optical conversion element 12 using the photonic crystal illustrated in this example is at 1000 ° C. Indicates the amount of power generation per unit area of the photoelectric conversion unit 30 when power is received and received by the element 31, that is, the power generation density.
In FIG. 7, “PD” on the vertical axis of the graph indicates the power generation density. In FIG. 7, “E” on the horizontal axis of the graph indicates voltage.
In FIG. 7, a line D indicates a case where both surfaces of the photoelectric conversion unit 30 are the photoelectric conversion elements 31, and a line S indicates a change in the power generation density when the photoelectric conversion element 31 is provided on one surface of the photoelectric conversion unit 30. Are respectively shown.

In this example, in the case of an open voltage of about 0.8 V suitable for a silicon solar cell, both sides of the photoelectric conversion unit 30 are the photoelectric conversion elements 31, and the photoelectric conversion element 31 is provided on one side of the photoelectric conversion unit 30. The power generation density of the photoelectric conversion unit 30 differs from that in the following case.
When both surfaces of the photoelectric conversion unit 30 are the photoelectric conversion elements 31, a power generation density of 2200 W per square meter is exhibited.
On the other hand, when the photoelectric conversion element 31 is provided only on one side of the photoelectric conversion unit 30, the power generation density is 1100 W per square meter.
That is, when both surfaces of the photoelectric conversion unit 30 are the photoelectric conversion elements 31, the power generation density of the photoelectric conversion unit 30 is about twice as large as when the photoelectric conversion element 31 is provided on one surface of the photoelectric conversion unit 30. Become. This leads to an increase in the power generation density with respect to the surface area of the heat source, and the power generation efficiency of the thermo-optical power generation device 100 becomes high.

Hereinafter, more preferable aspects of the thermo-optical power generation device 100 and the thermo-optical power generation system 1 will be described.
Between the heat supply unit 20 and the photoelectric conversion unit 30, a shielding unit 50 that shields radiation light from the heat supply unit 20 may be provided.
In this example, a light reflector 51 that reflects light is provided at the end of the photoelectric conversion unit 30 on the side facing the heat supply unit 20 as the shielding unit 50. The heat supply unit 20 is provided so as to reflect uncontrolled radiation emitted from the heat supply unit 20 and convert the reflected light into heat again by the heat supply unit 20.

The light reflector 51 only needs to reflect light. It is particularly preferable that the material of the reflecting surface is made of gold, silver, or aluminum, and that the material is exposed to the mirror surface.
In this example, a light reflector 51 on which a stainless steel flat plate is buffed with No. 300 and then electrolytically polished and gold is deposited is used.

  In the illustration of the thermophotovoltaic power generation device 100 and the thermophotovoltaic power generation system 1 shown in FIG. 1, utilities such as a supply path used for heat supply from the above-described heat source, cooling water used for cooling, and electric wiring for extracting generated power include: Although the description is omitted, known members and methods can be used.

[Another embodiment]
(1) In the above-described embodiment, an example has been described in which the thermophotovoltaic device 100 is stored in the vacuum space 60 of the cooling unit 40 which also serves as the vacuum container 61.
However, as shown in FIG. 6, the thermophotovoltaic power generation system 1 may be configured by providing the vacuum vessel 61 separately from the cooling unit 40 and providing the thermophotovoltaic power generation device 100 in the space 60.

(2) In the above embodiment, the radiating section 10 is provided upright with respect to the heat supply section 20 in the vertical direction of the heat supply section 20 in FIG. In the example shown in FIG.
However, as shown in FIG. 6, the radiating section 10 may be provided upright in only one direction with respect to the heat supply section 20.

(3) In the above embodiment, an example is shown in which the radiating section 10 and the photoelectric conversion section 30 are alternately repeated in the longitudinal direction of the heat supply section 20 and are provided side by side.
However, the radiation section 10 and the photoelectric conversion section 30 may be alternately provided in the circumferential direction of the heat supply section 20 and may be provided side by side. Specifically, for example, the heat supply unit 20 is formed in a cylindrical shape, the radiation unit 10 is erected on the cylindrical surface of the heat supply unit 20, and the photoelectric conversion unit 30 is provided to face the radiation unit 10. You may.

(4) In the above embodiment, a light reflector 51 that reflects light is provided at the end of the photoelectric conversion unit 30 on the side facing the heat supply unit 20 as the shielding unit 50. The case where the unsupplied radiation emitted by the heat supply unit 20 toward the unit 20 is reflected and converted to heat by the heat supply unit 20 again is exemplified.
However, as shown in FIG. 6, a heat insulating material 52 is used as the shielding unit 50, and the heat insulating material 52 is covered by the heat supply unit 20 so as to suppress uncontrolled radiation from the heat supply unit 20. You may comprise.

(5) In the above-described embodiment, the case where the photoelectric conversion unit 30 uses the photoelectric conversion element 31 which can receive light on both sides and generate power on both sides has been exemplified. The same photoelectric conversion element 31 may be attached to the back surface of the light receiving surface of the element 31 so that the back surface is bonded to each other.

  Note that the configuration disclosed in the above embodiment (including another embodiment, the same applies hereinafter) can be applied in combination with the configuration disclosed in another embodiment unless there is a contradiction. The embodiment disclosed in the present specification is an exemplification, and the embodiment of the present invention is not limited thereto, and can be appropriately modified without departing from the object of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be usefully used as a thermo-optical power generation device and a thermo-optical power generation system.

1: Thermophotovoltaic power generation system 10: Radiant part 11: Infrared transparent substrate 12: Thermo-optical conversion element (thermal radiation light source)
20: heat supply unit 30: photoelectric conversion unit 31: photoelectric conversion element 40: cooling unit 50: shielding unit 51: light reflector 52: heat insulating material 60: space 61: vacuum container 100: thermo-optical power generator

Claims (8)

A flat radiating section provided with a heat radiation light source that converts heat into radiation light, a heat supply section that supplies heat supplied from the heat source to the radiation section, and a photoelectric conversion element that receives the radiation light and generates power. And a flat-panel photoelectric conversion unit with
The radiating portion is erected on the heat supply portion so as to be able to conduct heat from the heat supply portion,
The photoelectric conversion unit is provided along with the radiation unit in a state where the photoelectric conversion element is opposed to the heat radiation light source,
A cooling unit that cools the photoelectric conversion unit,
The photoelectric conversion unit is erected on the cooling unit,
The photovoltaic power generation device, wherein the photoelectric conversion element is connected to the cooling unit so as to be able to conduct heat.   The thermoelectric generator according to claim 1, wherein the photoelectric conversion unit is a photoelectric conversion element having a photoelectric conversion surface on both surfaces. The radiating unit includes an infrared transparent substrate formed of a material that can transmit infrared light in a flat plate shape,
The infrared transparent substrate is provided with a heat-light conversion element for radiating radiation having a predetermined wavelength amplified as the heat radiation light source in a flat plate portion, and is connected to the heat supply portion so as to be able to conduct heat from the heat supply portion. The thermo-photovoltaic power generator according to claim 1 or 2, wherein   The thermoelectric generator according to any one of claims 1 to 3, wherein the radiator and the photoelectric converter are alternately provided.   The thermophotovoltaic power generation device according to any one of claims 1 to 4, further comprising a shielding unit between the heat supply unit and the photoelectric conversion unit, the shielding unit shielding radiation light from the supply unit.   The thermoelectric generator according to claim 5, wherein the shielding unit is a heat insulating material, and the heat insulating material is covered by the heat supply unit.   The thermoelectric generator according to claim 5, wherein the shielding unit is a light reflector that reflects light, and the light reflector is provided to reflect light toward the heat supply unit.   A thermophotovoltaic power generation system comprising the thermophotovoltaic device according to claim 1 in a vacuum vessel.

Images