JP2005304250A - Thermophtovoltaic generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermophotovoltaic generator with high power generation efficiency by preventing leakage of light to the outside of the generator. <P>SOLUTION: This thermophtovoltaic generator comprises: a combustion chamber 2; an emitter 3 having a shape surrounding the combustion chamber 2, and emitting the infrared ray heated to a high temperature by combustion in the combustion chamber 2; a plurality of photovoltaic cells 7 arranged on the opposite side to the direction of the combustion chamber 2 of the emitter 3 and at least being opposed to a part of surfaces of the emitter 3. The surface of the emitter 3 side of the combustion chamber 2 comprises a reflecting surface 4a. Thus, the radiated light directed toward the inside of the combustion chamber of the emitter 3 is recovered again by the emitter 3. Contribution is made to power generation by heating the emitter 3 in the photovoltaic cells 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermophotoelectric generator for converting infrared light emitted from a high heat source into electrical energy and outputting the same.

  A thermophotovoltaic power generation device (thermophotovoltaic-system) is a power generation device that mainly generates infrared light by heating an object called an emitter to a high temperature, receives the light with a photovoltaic cell, and extracts it as electric energy. In this apparatus, by adjusting the heating temperature of the emitter, it is possible to generate radiation with a spectrum corresponding to the high sensitivity region of the photovoltaic cell, thereby expecting high energy conversion efficiency, that is, power generation efficiency. it can. In addition, since there is no moving part, it is possible to realize a low noise and low vibration device, and the future is expected as a long-life, distributed power generation device.

  The currently developed thermophotoelectric generator has a structure in which a large number of photovoltaic cells are arranged around the light emitting surface of an emitter heated by a high-temperature combustion gas. In this case, in order to increase the power generation efficiency of the device, it is necessary for all the emitted light from the emitter to be received by the photovoltaic cell, and for this purpose, the photovoltaic cell is arranged close to and covering the light emitting surface of the emitter. The method of doing is taken. However, it is not possible to completely prevent the radiated light from leaking from the gaps between the arranged cells, and the configuration and arrangement of the light receiving surface of the photovoltaic cell are restricted by the configuration and arrangement of the emitter emitting surface, and the device design There is a drawback of reducing the degree of freedom. That is, it has a drawback that it is difficult to make the shape and arrangement of the light receiving surface and the emitter light emitting surface of the photovoltaic cell to be the shapes and arrangements in which each operates most efficiently.

  Further, although radiation from the emitter is performed from the entire surface of the emitter, in a device of a type in which a combustion chamber is provided on the back surface side of the emitter, the photovoltaic cell can be disposed only on the front surface side of the emitter. It cannot contribute to the power generation of the photovoltaic cell, and most of it is discharged to the outside as heat. As a result, the power generation efficiency of the device is greatly reduced.

  In addition, a technique (for example, see Patent Documents 1 and 2) that efficiently collects sunlight into a photovoltaic cell by using a prism or a lens and increases power generation efficiency has been developed. Adding new parts is not appropriate because it increases the size of the device and further reduces the degree of design freedom in the configuration and arrangement of the light receiving surface of the photovoltaic cell and the light emitting surface of the emitter.

JP 2001-77399 A JP 2001-313410 A JP 2002-354854 A JP 2003-168816 A

  The present invention has been made for the purpose of solving the above-described drawbacks of the thermophotovoltaic power generation apparatus that has already been developed, and provides flexibility in the structure and arrangement relationship between the emitter and the photovoltaic cell, and the emitter. It is an object of the present invention to provide a thermophotovoltaic power generation device that greatly improves power generation efficiency by guiding radiation emitted from the solar cell to a photovoltaic cell without loss.

  In order to solve the above-described problem, the thermophotoelectric generator according to the first invention has a combustion chamber and a shape surrounding the combustion chamber, and is heated to a high temperature by combustion in the combustion chamber to emit infrared light. A thermophotoelectric generator comprising an emitter and a plurality of photovoltaic cells arranged to face at least a part of a surface of the emitter opposite to the combustion chamber direction, and reflects the emitter side surface of the combustion chamber It is characterized by comprising a surface.

  In the above apparatus, since the surface of the combustion chamber facing the emitter is a reflecting surface, radiation emitted from the emitter toward the combustion chamber and not originally contributing to power generation by the photovoltaic cell is reflected by the emitter by reflection from the combustion chamber reflecting surface. It can be recovered. As a result, the emitter is further heated to a high temperature to increase the amount of radiation and shift the peak wavelength in the radiation spectrum to the short wavelength side. As a result, the effective wavelength radiation amount of photoelectric conversion in the photovoltaic cell is increased, and the photovoltaic cell output is increased.

  Moreover, in the thermophotoelectric generator according to the second invention, an emitter that emits infrared light by heating to a high temperature, and a plurality of photovoltaic cells that are disposed to face at least a part of the emission surface of the emitter, A reflecting plate that substantially surrounds the radiation surface of the emitter together with the plurality of photovoltaic cells, and the reflecting plate guides the emitted light from the emitter to the plurality of photovoltaic cells. It is characterized by that.

  In the above apparatus, since the emission surface of the emitter is substantially surrounded by the reflector and the plurality of photovoltaic cells, leakage of the emitted light from the emitter to the outside of the apparatus is effectively prevented. Further, since the emitted light from the emitter is guided by the reflecting plate and travels to the plurality of photovoltaic cells, it is not necessary that the light receiving area of the plurality of photovoltaic cells surround the entire radiation surface of the emitter. Therefore, the light receiving area of the plurality of photovoltaic cells can be set to a value that can receive the radiated light from the emitter with the light receiving density with the highest power generation efficiency, and the power generation efficiency of the device can be further increased.

  Furthermore, in the thermophotoelectric generator according to the third invention, in the thermophotoelectric generator of the first invention, the surface of the emitter opposite to the combustion chamber is substantially surrounded together with the plurality of photovoltaic cells. A reflection plate is provided, and radiation from the emitter is guided to the plurality of photovoltaic cells by the reflection plate.

  According to this apparatus, radiation directed from the emitter toward the combustion chamber can be collected by the emitter by the reflection surface of the combustion chamber and contribute to power generation in the photovoltaic cell. At the same time, the light emitted from the emitter in the direction of the plurality of photovoltaic cells is guided in the direction of the plurality of photovoltaic cells by the reflector without leaking to the outside of the apparatus. As a result, the power generation efficiency of the thermoelectric power generator can be further improved.

[Example 1]
FIG. 1 is a cross-sectional view showing a schematic configuration of a thermophotovoltaic power generator according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a cylindrical casing made of a heat-resistant ceramic, and has a combustion chamber 2 and an emitter 3 provided so as to surround the combustion chamber 2 therein. The combustion chamber 2 is constituted by a cylindrical guide 4 provided so as to surround a nozzle 5 for supplying combustion gas and air. The surface 4a facing the emitter of the cylindrical guide 4 is a reflective surface (first reflective surface) by mirror finish such as gold plating. The reflecting surface 4a can be constituted by an aluminum or stainless steel polished surface, or by vapor deposition of gold, silver, platinum, aluminum or the like. The material for the reflective surface is appropriately selected according to demands for oxidation resistance and heat resistance.

The emitter 3 is made of a porous ceramic made of SiC, Yb ₂ O ₃ or the like, and emits infrared light efficiently by being heated to about 1500 ° C., for example. A light selection filter 6 is coated on quartz glass or the like, transmits light having a wavelength effective for power generation in the photovoltaic cell, reflects light having a wavelength not contributing to power generation, and makes the photovoltaic cell unnecessary. It is prevented from being heated. 7 is a photovoltaic module provided on the inner bottom surface of the housing 1, and is configured by connecting a number of photovoltaic cells in series or in series-parallel. Reference numeral 8 denotes a cooling block for the photovoltaic module 7.

  In the present apparatus, a second reflecting surface 9 is formed on the entire inner wall other than the bottom surface of the housing 1. Similar to the first reflecting surface, the reflecting surface 9 is configured by mirror finish such as gold plating, stainless steel or aluminum.

  In FIG. 1, 10 is a heat exchanger, 11 is an exhaust port, and 12 is an air introduction pipe. Fuel such as butane is introduced into the casing from an inlet (not shown) (not shown), and is introduced from the nozzle 5 into the combustion chamber 2 together with air to burn. The combustion gas is guided to the bottom of the emitter 3 by the cylindrical guide 4, and then uniformly heated while rising along the side wall of the emitter 3, and is guided to the heat exchanger 10 through the opening 14. In the heat exchanger 10, heat exchange is performed between the air introduced from the air guide pipe 12 and the exhausted combustion gas, the air is heated and the combustion gas is cooled, and is discharged from the exhaust port 11 to the outside. Is done.

  As described above, in the thermophotovoltaic power generation device shown in Example 1, the photovoltaic cell module is disposed only on the inner bottom surface of the device, the reflective surface is formed on the other inner wall of the device, and the cylindrical shape constituting the combustion chamber A feature is that the surface of the guide 4 (the surface facing the emitter 3) is a reflecting surface.

  Below, with reference to FIG. 2, the effect of the thermophotoelectric generator concerning Example 1 is demonstrated. In FIG. 2, an arrow 15 indicates light emitted from the inner surface of the emitter 3, that is, the surface facing the combustion chamber 2, and an arrow 16 indicates light emitted from the outer surface of the emitter 3, that is, the surface in the inner wall direction of the housing 1. Indicates. The emitter 3 outputs radiated light when heated to a high temperature, and has no directivity in the radiation direction, and thus radiation occurs in the same manner on both sides of the emitter 3. The light 15 emitted from the inner surface of the emitter 3 is reflected by the reflecting surface 4a (first reflecting surface) of the cylindrical guide 4 constituting the combustion chamber, enters the emitter 3 again, is absorbed, and heats the emitter 3.

  This heating causes the emitter 3 to have a higher temperature, increasing the amount of radiation. Further, as the temperature of the emitter rises, the peak wavelength of the radiation spectrum shifts to the short wavelength side. Since the photovoltaic cell has high power generation efficiency in a short wavelength region, the proportion of the wavelength effective for photoelectric conversion in the radiation spectrum, that is, the effective wavelength rate is improved. As a result, power generation efficiency is improved. In this way, in this apparatus, the light radiated in the direction of the combustion chamber of the emitter and radiated without originally contributing to the power generation of the photovoltaic cell can be collected and effectively contributed to the power generation of the photovoltaic cell.

  Further, as shown in FIG. 2, the light 16 emitted toward the inner wall of the casing 1 of the emitter 3 is reflected directly or by the second reflecting surface 9, and almost all of the light 16 is disposed on the bottom surface of the casing 1. The light enters the photovoltaic module and is received. Since most of the inner wall of the housing 1 is covered with the reflecting surface except for the bottom surface, light does not leak outside through the wall surface of the housing 1 and is not absorbed by the wall material. Therefore, radiation from the emitter can be received by the photovoltaic module without loss and contribute to power generation.

  In addition, since the cell-side light emitting surface of the emitter is surrounded by a reflector and the emitted light from the emitter is guided in the direction of the photovoltaic module, the emitter emitting surface and the light receiving surface of the photovoltaic module are designed to be independent from each other. This increases the degree of freedom in device design. As a result, the emitter light-emitting surface and the photovoltaic module light-receiving surface can adopt shapes and sizes that exhibit peak values in their respective performances, so that the power generation efficiency of the thermophotoelectric generator can be further improved. In addition, since the degree of freedom of the shape of the thermophotoelectric generator increases, there is an advantage that restrictions on the shape are reduced, for example, when an in-vehicle thermophotoelectric generator is configured.

The relationship between the shape and efficiency of the emitter light emitting surface and the photovoltaic module light receiving surface will be briefly described below. The radiant heat quantity Q of the emitter is represented by Q = εσT ⁴ A. Here, ε is the emissivity of the emitter material, σ is the Stefan Boltzmann coefficient (radiation coefficient), T is the emitter emission surface temperature, and A is the emission area. Now, when the emitter is going to radiate a certain amount of heat Q1, it is most efficient from the heating mechanism and structure of the emitter to raise the temperature to T1 and to set the light emission area to A1.

  On the other hand, since the power generation efficiency of the photovoltaic cell changes depending on the light reception density, there is a cell area A2 having the highest power generation efficiency when receiving a certain amount of heat Q1. Here, the areas A1 and A2 are usually different from each other. However, in the conventional thermophotovoltaic power generation device, the emitter area A1 or the cell is arranged because the light receiving cell is arranged around the emitter in order to prevent light leakage. It was necessary to determine any of the areas A2 at the expense of their efficiency.

  However, in the thermophotovoltaic power generation device shown in FIG. 1, the emitter area A1 and the cell area A2 are both set to values that indicate peak operation performance, and the portions having different areas are configured by the reflecting surface to transmit the radiated light to the cell. By guiding up, there is no need to determine the area at the expense of efficiency for both the emitter and the cell. Therefore, it is possible to further improve the power generation efficiency of the thermal light power generation device.

[Example 2]
FIG. 3 is a cross-sectional view showing a schematic configuration of a thermophotovoltaic power generator according to Embodiment 2 of the present invention. In the drawings showing the following embodiments, the same reference numerals as those shown in FIG. 1 indicate the same or similar members, and therefore, the description thereof will not be repeated.

  As shown in the drawing, the thermophotovoltaic power generator according to the second embodiment is characterized by a structure in which the lower part of the side wall 1a of the housing 1 is deformed in the direction of narrowing the area of the bottom surface of the housing 1. By deforming the lower part of the side wall 1a as shown in the figure, the installation area of the photovoltaic module 7 is reduced, and the cells can be arranged in a smaller area than the embodiment shown in FIG. Since the inner surface of the wall surface 1a is the reflective surface 9 as in the first embodiment, most of the radiated light generated from the emitter 3 is reflected by the reflective surface 9 or directly from the emitter 3 to the photovoltaic module 7. Incident light does not leak outside the housing. Therefore, in this embodiment, if the light emission amount of the emitter 3 is the same, the light receiving density of the photovoltaic cell is higher than that of the first embodiment.

[Example 3]
FIG. 4 is a cross-sectional view illustrating a schematic configuration of the thermophotovoltaic power generator according to Embodiment 3 of the present invention. In the apparatus of the present embodiment, the bottom surface of the housing 1 is made larger than the devices of the first and second embodiments, and the inner wall 1b of the housing 1 is curved so as to expand toward the bottom surface. It has its characteristics. That is, the side wall 1b of the present embodiment is configured in the shape of a lamp umbrella so that the radiated light from the central emitter 3 is reflected in the direction where the umbrella is opened, that is, in the direction of the installation surface of the photovoltaic module 7. As a result, the emitted light from the emitter 3 can be more uniformly irradiated to the photovoltaic module 7. This embodiment is suitable for increasing the area of the light receiving surface of the photovoltaic module 7 as compared with the first and second embodiments and reducing the light receiving density of the cells.

[Example 4]
FIG. 5: is sectional drawing which shows schematic structure of the thermophotovoltaic power generating apparatus concerning Example 5 of this invention. In the figure, 20 is a cylindrical casing, and 21 is a wall surface for installing a photovoltaic module provided in the casing 20. On the wall surface 21, the photovoltaic module 22 is installed so as to surround the emitter 23. Reference numeral 24 denotes a combustion chamber, 25 denotes a combustion chamber side wall member, 26 denotes an air outlet, 27 denotes a fuel gas inlet, 28 denotes an air and fuel gas mixing chamber, and 29 denotes an air inlet. Further, a filter 30 for reflecting light that does not contribute to power generation in the photovoltaic module 22 is provided outside the emitter 23.

  In the apparatus of FIG. 5, the air introduced from the air inlet 29 reaches the heat exchanger 31 while cooling the photovoltaic module 22, where heat exchange with the exhaust gas is performed and the air is heated to a high temperature. Thereafter, the mixture is supplied to the mixing chamber 28 through the air jet 26. On the other hand, fuel gas such as butane is supplied from the inlet 27 to the mixing chamber 28 where it is mixed with air and supplied to the combustion chamber 24 for combustion. The combustion gas rises while heating the emitter along the side wall of the emitter 23, and is discharged to the outside through the heat exchanger 31 through the exhaust port 32. Reference numeral 33 denotes a cooling member that cools the photovoltaic module 22 from behind.

  In the present apparatus, a reflective surface 25 a similar to the first reflective surface shown in Examples 1 to 3 is formed on the surface of the side wall member 25 constituting the combustion chamber 24 facing the emitter 23. Therefore, when the emitter 23 is heated by the combustion gas and emits radiated light, the radiated light that does not originally contribute to power generation in the photovoltaic cell in the direction of the combustion gas is reflected in the direction of the emitter 24 by the reflecting surface 25a. As a result, the emitter 24 is heated to a higher temperature, increasing the amount of radiation in the direction of the photovoltaic cell, and improving the effective wavelength ratio contributing to power generation.

  In the present embodiment, the material of each part of the thermophotovoltaic power generation device, the configuration of the reflection surface, etc. are the same as or similar to those described in the first embodiment. Absent.

  As described above, the thermophotoelectric generator according to the first invention of the present invention, as described above with reference to various embodiments, originally generates power in the photovoltaic cell by making the emitter side surface of the combustion chamber a reflective surface. The emitted light energy of the emitter that does not contribute to the energy can be recovered by the emitter and contribute to the power generation of the photovoltaic cell. Therefore, the power generation efficiency of the thermal light power generation device is greatly improved.

  Moreover, in the thermophotovoltaic power generator according to the second aspect of the present invention, since the light emitting surface of the emitter in the direction of the photovoltaic cell is surrounded by the reflecting surface and the photovoltaic cell, the emitted light from the emitter is outside the casing. Leakage can be effectively prevented, and the area of the photovoltaic cell can be freely selected regardless of the shape of the emitter. Therefore, the thermoluminescent power generator can be configured by setting the light emitting efficiency of the emitter and the light receiving efficiency of the photovoltaic cell to the highest, and the power generating efficiency can be further improved. In addition, since the degree of freedom in selecting the shape is improved, it is easy to obtain a structure suitable for special applications such as in-vehicle use.

  Moreover, the power generation efficiency of the apparatus can be further improved by configuring a thermophotovoltaic power generation apparatus that combines the first invention and the second invention.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows schematic structure of the thermophotovoltaic power generating apparatus concerning the 1st Example of this invention. The figure for showing the operation effect of the device of Drawing 1. Sectional drawing which shows schematic structure of the thermophotovoltaic power generating apparatus concerning the 2nd Example of this invention. Sectional drawing which shows schematic structure of the thermophotovoltaic power generating apparatus concerning the 3rd Example of this invention. Sectional drawing which shows schematic structure of the thermophotovoltaic power generating apparatus concerning the 4th Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylindrical housing | casing 2 ... Combustion chamber 3 ... Emitter 4 ... Cylindrical guide 4a ... 1st reflective surface 5 ... Nozzle 6 for supply of combustion gas and air ... Filter 7 ... Photovoltaic module 8 ... Cooling block 9 ... 2nd Reflecting surface 10 ... Heat exchanger 11 ... Exhaust port 12 ... Air inlet port

Claims (5)

  A combustion chamber, an emitter having a shape surrounding the combustion chamber, heated to a high temperature by combustion in the combustion chamber and emitting infrared light, and at least a part of the surface of the emitter opposite to the combustion chamber direction A thermophotoelectric generator comprising a plurality of photovoltaic cells disposed opposite to each other, wherein the emitter side surface of the combustion chamber is formed of a reflective surface.   In a thermophotovoltaic power generation apparatus comprising an emitter that emits infrared light by heating to a high temperature, and a plurality of photovoltaic cells disposed to face at least a part of the emission surface of the emitter, the emission surface of the emitter is A thermophotovoltaic power generation apparatus, comprising: a reflector that substantially surrounds the plurality of photovoltaic cells, wherein radiation from the emitter is guided to the plurality of photovoltaic cells by the reflector.   3. The thermophotovoltaic power generator according to claim 2, wherein the light receiving area of the plurality of photovoltaic cells is set to a value capable of receiving radiated light from the emitter at a light receiving density with the highest power generation efficiency. A thermoelectric power generation device.   2. The thermophotovoltaic generator according to claim 1, further comprising a reflecting plate that substantially surrounds the surface of the emitter opposite to the combustion chamber together with the plurality of photovoltaic cells, and the emitter emits radiation from the emitter. Is guided to the plurality of photovoltaic cells.   5. The thermophotovoltaic power generator according to claim 4, wherein the light receiving areas of the plurality of photovoltaic cells are set to values capable of receiving radiated light from the emitter at a light receiving density with the highest power generation efficiency. A thermoelectric power generation device.

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