JP5438451B2 - Thermoelectric conversion generator - Google Patents

Description

  The present invention relates to a thermoelectric conversion power generation apparatus that generates power from a temperature difference between a high temperature side and a low temperature side using a thermoelectric conversion module, and in particular, a boundary wall between a high temperature atmosphere side and a low temperature heat atmosphere side caused by the temperature difference. The present invention relates to a thermoelectric conversion power generation device that does not cause a decrease in power generation efficiency caused by deformation (hereinafter referred to as “boundary wall”).

  Generally, a heat engine is known as a temperature difference power generation widely used at present. Since the heat engine is a device based on mechanistics, it has a movable part, and therefore, wear deterioration cannot be avoided in principle. On the other hand, in the case of temperature difference power generation using a thermoelectric conversion element, the basic structure of the thermoelectric conversion element is a semiconductor junction based on solid state physics. It has features such as not.

  Therefore, temperature difference power generation using thermoelectric conversion elements has advantages such as long-term reliability compared to heat engines, and the ability to mount devices in a wide range of dimensions from small to large. . Due to such characteristics, the thermoelectric conversion element is expected to be applied to power generation that reuses waste heat, which has been impossible for conventional heat engines.

  When temperature difference power generation is performed using a thermoelectric conversion element, thermoelectric conversion elements made of p-type and n-type semiconductors are usually arranged alternately in series on a ceramic substrate such as alumina, and each of the p-type and n-type thermoelectric elements is arranged. A thermoelectric conversion module having a structure in which conversion elements are connected by electrodes is used (see, for example, Patent Documents 1 to 3).

  A thermoelectric conversion power generator that generates heat from a temperature difference between a high temperature side and a low temperature side by sandwiching a thermoelectric conversion unit having a cooling plate in contact with such a thermoelectric conversion module between the high temperature atmosphere side and the low temperature atmosphere side. (For example, refer patent document 4). There is a boundary wall between the high temperature atmosphere side and the low temperature atmosphere side, and the thermoelectric conversion unit is usually disposed on the low temperature atmosphere side so as to be in contact with the boundary wall.

JP-A-5-29667 JP 2005-302783 A JP 2000-164941 A JP 11-8988 A

  As described above, in the conventional thermoelectric conversion power generation apparatus, the thermoelectric conversion unit is arranged on the low temperature atmosphere side of the boundary wall to generate power. However, as shown in FIG. When a thermoelectric conversion unit is installed to generate power from a temperature difference from the high temperature atmosphere side, first, as shown in FIG. 5A, a thermoelectric conversion unit 53 comprising a thermoelectric conversion module 51 and a cooling plate 52 is installed. Initially, the boundary wall 54 and the thermoelectric conversion unit 53 are in close contact.

  As shown in FIG. 5B, over time, the boundary wall 54 is deformed (warped) due to thermal expansion due to the temperature difference between the high temperature atmosphere side and the low temperature atmosphere side. When the field wall is warped as described above, a space G is generated between the field wall 54 and the thermoelectric conversion unit 53, and the heat transfer efficiency from the high temperature atmosphere side to the thermoelectric conversion unit 53 is extremely reduced. It was.

  Further, if the thermoelectric conversion unit 53 is pressed against the boundary wall 54 so as to eliminate the space G between the boundary wall 54 and the thermoelectric conversion unit 53 as much as possible, the boundary wall 54 has already been subjected to thermal strain. The strain in the wall is further increased. In this case, when the boundary wall deformation resulting from the thermal expansion and the strain caused by the pressing force of the thermoelectric conversion unit 53 exceeds the amount of elastic-plastic deformation of the material constituting the boundary wall, as shown in FIG. There was also a problem of the possibility of destruction. The thermoelectric conversion module 51 is basically composed of a thermoelectric conversion element and an electrode, but is shown as an integral unit in this figure.

  This problem is partly due to the difference in the coefficient of thermal expansion of each member constituting the power generation device, and the difference in the coefficient of thermal expansion of each member is caused by the displacement of the component member (from the position where it should originally be). Misalignment) and deformation, resulting in reduced heat transfer efficiency and poor conduction.

  In addition, the mechanical balance applied to each constituent member is biased, and both the deformation due to thermal expansion and the pressing force of the thermoelectric conversion unit have the effect of bending the boundary wall to the high temperature atmosphere side, The only reaction force is the rigidity of the wall (Young's modulus). If the reaction force is to be increased, the rigidity of the field wall must be increased by increasing the thickness of the field wall or adding a reinforcing structure such as a rib to the field wall. However, such a method reduces the heat transfer capability of the field wall and is difficult to adopt because it complicates the situation of deformation (warpage) of the field wall.

  Furthermore, in addition to the above problems, there are restrictions on material selection depending on the use temperature. When designing the strength of the power generation device, it is necessary to consider what mechanical properties the components have in a high temperature atmosphere. At that time, in order to prevent the displacement of the component due to the difference in thermal expansion coefficient described above, it is necessary to provide the component with a hook elastic region called “play” or to apply a strong reaction force to suppress the displacement. There is. Materials that meet these constraints will be selected based on the mechanical database of the materials, but there are few materials that have adequate elasticity and rigidity at high temperatures, which is particularly necessary for heat transfer path design. Considering the thermal properties, the choice of materials used is very large.

  The present invention has been made in order to solve the above-described problems. In consideration of the transfer efficiency and the mechanical balance of heat flowing from the high temperature atmosphere side to the low temperature atmosphere side, even if the boundary wall is deformed, the power generation efficiency The thermoelectric conversion electric power generating apparatus which does not reduce this is provided.

In order to achieve this object, a first aspect of the thermoelectric conversion power generator of the present invention obtains a power generation output from a temperature difference between a high temperature atmosphere side and a low temperature atmosphere side using a thermoelectric conversion module comprising a plurality of thermoelectric conversion elements. In the thermoelectric conversion power generator, a heat transfer medium made of ceramics having high thermal conductivity and heat resistance having a melting point of 1000 ° C. or higher is attached so as to penetrate through the boundary walls between the high temperature atmosphere side and the low temperature atmosphere side, and the heat transfer medium A thermoelectric conversion unit including a thermoelectric conversion module and a cooling plate is arranged on the low temperature atmosphere side of the.

Further, the second aspect of the thermoelectric conversion power generator of the present invention is a thermoelectric conversion power generator that obtains a power generation output from a temperature difference between a high temperature atmosphere side and a low temperature atmosphere side using a thermoelectric conversion module composed of a plurality of thermoelectric conversion elements. A heat transfer medium is attached so as to penetrate the boundary wall between the high temperature atmosphere side and the low temperature atmosphere side. The volume of the heat transfer medium on the high temperature atmosphere side is larger than the volume on the low temperature atmosphere side. A thermoelectric conversion unit including a thermoelectric conversion module and a cooling plate is disposed.

Furthermore, a third aspect of the thermoelectric conversion power generator of the present invention is characterized in that, in the first or second aspect, the heat transfer medium has at least one plane.

The fourth aspect of the thermoelectric conversion power generation device of the present invention, in a third aspect, wherein the thermoelectric conversion unit in one plane of the heat transfer medium is arranged.

Furthermore , the fifth aspect of the thermoelectric conversion power generation apparatus of the present invention is characterized in that, in the third aspect, thermoelectric conversion units are arranged on a plurality of planes of the heat transfer medium.

According to a sixth aspect of the thermoelectric conversion power generator of the present invention, in the first aspect, the ceramic is one selected from silicon carbide, silicon nitride, and aluminum nitride.

Furthermore, according to a seventh aspect of the thermoelectric conversion power generator of the present invention, in the first to sixth aspects, the heat transfer medium is a flat plate.

According to an eighth aspect of the thermoelectric conversion power generator of the present invention, in the first to sixth aspects, the heat transfer medium is a rod-shaped body.

Furthermore, the ninth aspect of the thermoelectric conversion power generator of the present invention is characterized in that, in the first to sixth aspects, the heat transfer medium is an L-shaped body.

According to a tenth aspect of the thermoelectric conversion power generator of the present invention, in the first to sixth aspects, the heat transfer medium is an arch-like body.

Furthermore, the eleventh aspect of the thermoelectric conversion power generator of the present invention is characterized in that, in the first to tenth aspects, the boundary wall is flat.

The twelfth aspect of the thermoelectric conversion power generator of the present invention is characterized in that, in the first to tenth aspects, the field wall is cylindrical.

Furthermore, in a thirteenth aspect of the thermoelectric conversion power generator of the present invention, in the first to twelfth aspects, the thermoelectric conversion module is constituted by a thermoelectric conversion element comprising a p-type oxide semiconductor and an n-type oxide semiconductor. It is characterized by.

In addition , the fourteenth aspect of the thermoelectric conversion power generator of the present invention is the thirteenth aspect, wherein the oxide-based thermoelectric conversion element is a p-type oxide-based semiconductor composed of sodium cobalt oxide, calcium cobalt oxide, or calcium bismuth. It is one selected from cobalt oxides, and the n-type oxide semiconductor is one selected from zinc oxide, lanthanum nickel oxide, calcium manganese oxide, or strontium titanium oxide. .

  According to the thermoelectric conversion power generation device of the present invention, the heat transfer medium is attached to the boundary wall so as to penetrate, and the heat transfer conversion unit is disposed on the low temperature atmosphere side of the heat transfer medium. Even if the boundary wall is deformed (warped) due to the temperature difference from the side, no harmful deformation is applied to the heat transfer unit, and heat from the high-temperature atmosphere side is efficiently transferred through the heat transfer medium. Therefore, power generation efficiency is not reduced.

It is a perspective view which shows one Embodiment of the thermoelectric conversion electric power generating apparatus of this invention. It is a figure explaining the arrangement | positioning condition of the thermoelectric conversion unit in the thermoelectric conversion electric power generating apparatus of this invention. It is a figure explaining the attachment condition of the thermoelectric conversion electric power generating apparatus of this invention. It is a figure which shows other embodiment of the thermoelectric conversion electric power generating apparatus of this invention. It is a figure which shows an example of the conventional thermoelectric conversion electric power generating apparatus.

  Hereinafter, preferred embodiments of the thermoelectric conversion power generator of the present invention will be described with reference to the drawings. In addition, in description of each figure after that, the same code | symbol shall be attached | subjected about the same location.

  FIG. 1 is a perspective view showing an embodiment of a thermoelectric conversion power generator according to the present invention. In FIG. 1, a thermoelectric conversion power generator 1 of the present invention is attached to a field wall 2 between a high temperature atmosphere side and a low temperature atmosphere side so that a heat transfer medium 3 penetrates the field wall 2.

  A thermoelectric conversion unit 6 including a thermoelectric conversion module 4 including a thermoelectric conversion element and electrodes and a cooling plate 5 is disposed on the low temperature atmosphere side (room temperature side) of each heat transfer medium 3. In addition, in FIG. 1, it has decomposed | disassembled and shown so that it may be easy to understand how the thermoelectric conversion unit 6 is arrange | positioned at the heat transfer medium 3. FIG.

  Here, the heat transfer medium 3 preferably has at least one plane. The thermoelectric conversion module 4 has a structure in which thermoelectric conversion elements made of p-type and n-type semiconductors are alternately arranged in series on a ceramic substrate, and the p-type and n-type thermoelectric conversion elements are connected by electrodes. However, since the ceramic substrate has a flat plate shape, it is preferable that the heat transfer medium 3 also has at least one plane in order to bring the thermoelectric conversion unit 6 into close contact with the heat transfer medium 3.

  The heat transfer medium 3 is preferably a material having high heat conductivity and heat resistance, and a metal or ceramic having a melting point of 1000 ° C. or higher is used. Specifically, the metal is preferably a nickel alloy, martensitic stainless steel, copper, silver, tungsten, platinum or the like, and the ceramic is preferably silicon carbide, silicon nitride, aluminum nitride or the like.

  In the thermoelectric conversion elements constituting the thermoelectric conversion module 4, p-type and n-type semiconductor elements are alternately arranged, and p-type and n-type elements are paired and connected in series with electrodes. . As such a thermoelectric conversion element, a thermoelectric conversion element made of an oxide-based semiconductor is preferable. Examples of the p-type oxide-based semiconductor include sodium cobalt oxide, calcium cobalt oxide, or calcium bismuth cobalt oxide. Examples of the n-type oxide semiconductor include zinc oxide, lanthanum nickel oxide, calcium manganese oxide, and strontium titanium oxide. Since an oxide-based thermoelectric conversion element can be operated in a high temperature region close to 1000 ° C., it has an advantage of high application temperature.

  As the cooling plate 5, for example, a copper cooling plate is used, which is filled with cooling water at a temperature lower than room temperature, for example, about 10 ° C.

  Here, in FIG. 1, although the several heat transfer medium 3 is attached, the heat transfer medium 3 may be one. Moreover, as shown in FIG. 2, the thermoelectric conversion unit 6 can select various arrangement | positioning conditions. FIG. 2 is a view seen from the direction of arrow A in FIG. 1 (upward direction of the boundary wall), and the same applies to the following drawings.

  In FIG. 2A, the thermoelectric conversion unit 6 is disposed only on one plane on the low temperature atmosphere side of the heat transfer medium 3 having a flat plate shape or a rod shape. In FIG. 2 (b), the thermoelectric conversion units 6 are symmetrically arranged on two opposing planes on the low temperature atmosphere side of the heat transfer medium 3. Disposing the thermoelectric conversion units 6 symmetrically on the two planes of the heat transfer medium 3 has an advantage that the force applied to the heat transfer medium 3 is balanced, so that the heat transfer medium 3 is hardly deformed.

  Furthermore, as shown in FIG.2 (c), the heat transfer medium 3 may be made into an L-shaped body, and the thermoelectric conversion unit 6 may be arrange | positioned on two planes of the front-end | tip part 3a. In this case, although not shown, the thermoelectric conversion unit 6 may be disposed only on one plane of the tip 3a of the heat transfer medium 3. Note that the thermoelectric conversion unit 6 may be arranged on one or a plurality of planes of the portion (b portion of the L-shaped body) 3 b perpendicular to the field wall 2 of the L-shaped heat transfer medium 3.

  Further, as shown in FIG. 2 (d), the heat transfer medium 3 may be formed in an arch shape, and the thermoelectric conversion units 6 may be arranged on two opposing planes of a portion 3 c parallel to the field wall 2. Of course, although not shown, the thermoelectric conversion unit 6 may be disposed only in one plane of the portion 3c parallel to the field wall 2, and the portion perpendicular to the field wall 2 of the arch-shaped heat transfer medium 3 may be used. (A leg portion of the arch-like body) The thermoelectric conversion unit 6 may be arranged on one or a plurality of planes of 3d.

  In FIG. 2C, the thermoelectric conversion unit 6 may be arranged on both the tip 3a of the L-shaped heat transfer medium 3 and the portion 3b perpendicular to the boundary wall 2. FIG. ), The thermoelectric conversion unit 6 may be arranged in both the portion 3c parallel to the field wall 2 of the arch-shaped heat transfer medium 3 and the portion 3d perpendicular to the field wall 2. Any of them may be arranged on only one plane, and may be arranged on a plurality of planes.

  As shown in FIG. 3, the thermoelectric conversion power generator 1 according to the present invention having the above-described configuration is not affected by the deformation even if the boundary wall 2 is deformed, and the power generation efficiency is not lowered. . FIG. 3 is a view showing a state where the thermoelectric conversion power generator 1 of the present invention is attached. FIG. 3A is a diagram showing a situation in which the boundary wall 2 is not yet deformed, and the heat transfer medium 3 in which the thermoelectric conversion unit 6 is arranged is attached so as to penetrate the boundary wall 2.

  On the other hand, FIG. 3B shows a state in which the field wall 2 is deformed due to a temperature difference between the high temperature side atmosphere and the low temperature side atmosphere (room temperature side), and warpage occurs. Even when the boundary wall 2 is in such a state, the heat transfer medium 3 in which the thermoelectric conversion unit 6 is arranged is not affected by the deformation, and heat from the high temperature atmosphere side is efficiently transferred through the heat transfer medium 3. Since it is transmitted to the conversion unit 6, the power generation efficiency is not reduced.

  By the way, in the said embodiment, although the example which attached the heat transfer medium to the planar boundary wall was demonstrated, for example, the heat of cylindrical piping in which high temperature gas is flowing as a high temperature atmosphere side is utilized. Even in such a case, the thermoelectric conversion power generator of the present invention can be applied.

  FIG. 4 shows an embodiment in which the thermoelectric conversion power generator according to the present invention is applied to a cylindrical pipe. The cylindrical pipe 7 serves as a boundary wall, and the heat in which the thermoelectric conversion unit 6 is arranged in this pipe portion. A transmission medium 3 is attached.

  In the present embodiment, the heat transfer medium 3 is attached in four directions at an angle of 90 degrees. However, the number of heat transfer media 3 to be attached is not particularly limited, and may be one or plural. There is no problem. Moreover, when attaching the some heat transfer medium 3, you may attach at an equal angle and you may attach at arbitrary angles.

  In order to efficiently take heat into the heat transfer medium and transmit it to the thermoelectric conversion unit, the heat transfer medium preferably has a larger volume on the high temperature atmosphere side than on the low temperature atmosphere side. In this case, the shape of the heat transfer medium may be the same on the high temperature atmosphere side and the low temperature atmosphere side as shown in FIGS. 1 to 4, and the length of the high temperature atmosphere side may be increased. Alternatively, the shape of the heat transfer medium can be made different between the high temperature atmosphere side and the low temperature atmosphere side so that the volume on the high temperature atmosphere side is larger than the volume on the low temperature atmosphere side and heat can be taken in more efficiently. Good.

  According to the thermoelectric conversion power generation device of the present invention as described above, the heat transfer medium is attached to the boundary wall so as to penetrate, and the heat transfer conversion unit is disposed on the low temperature atmosphere side of the heat transfer medium. Even if the boundary wall is deformed (warped) due to the temperature difference between the temperature side and the low-temperature atmosphere side, the thermoelectric conversion unit is not harmfully deformed, and the heat from the high-temperature atmosphere side is efficiently transferred through the heat transfer medium. It is possible to obtain a thermoelectric conversion power generation device that does not cause a decrease in power generation output because it is transmitted to the thermoelectric conversion unit.

1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Thermoelectric conversion power generator 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wall 3 ・ ・ ・ ・ ・ ・..... Heat transfer medium 4 ..... Thermoelectric conversion module 5 .....・ ・ Cooling plate 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Thermoelectric conversion unit 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Piping

Claims (14)

In a thermoelectric conversion power generation device that uses a thermoelectric conversion module composed of a plurality of thermoelectric conversion elements to obtain power generation output from the temperature difference between the high temperature atmosphere side and the low temperature atmosphere side, so as to penetrate through the boundary wall between the high temperature atmosphere side and the low temperature atmosphere side Is mounted with a heat transfer medium made of ceramic having a high thermal conductivity and heat resistance having a melting point of 1000 ° C. or higher, and a thermoelectric conversion unit comprising the thermoelectric conversion module and a cooling plate is provided on the low temperature atmosphere side of the heat transfer medium. A thermoelectric conversion power generator characterized by being arranged. In a thermoelectric conversion power generation device that uses a thermoelectric conversion module composed of a plurality of thermoelectric conversion elements to obtain power generation output from the temperature difference between the high temperature atmosphere side and the low temperature atmosphere side, so as to penetrate through the boundary wall between the high temperature atmosphere side and the low temperature atmosphere side The heat transfer medium has a volume on the high temperature atmosphere side larger than a volume on the low temperature atmosphere side, and the heat transfer medium includes the thermoelectric conversion module and the cooling plate on the low temperature atmosphere side of the heat transfer medium. A thermoelectric conversion power generator, wherein a thermoelectric conversion unit is arranged. Thermoelectric power generating device according to claim 1 or claim 2, wherein said heat transfer medium is characterized in that it comprises at least one plane. The thermoelectric conversion power generator according to claim 3 , wherein the thermoelectric conversion unit is arranged on one plane of the heat transfer medium. The thermoelectric conversion power generator according to claim 3 , wherein the thermoelectric conversion units are arranged on a plurality of planes of the heat transfer medium. The ceramic thermoelectric power generating device according to claim 1, wherein the silicon carbide, silicon nitride, is one selected from aluminum nitride. The thermoelectric conversion power generator according to any one of claims 1 to 6, wherein the heat transfer medium is a flat body. The thermoelectric conversion power generator according to any one of claims 1 to 6, wherein the heat transfer medium is a rod-shaped body. The thermoelectric conversion power generator according to any one of claims 1 to 6, wherein the heat transfer medium is an L-shaped body. The thermoelectric conversion power generator according to any one of claims 1 to 6, wherein the heat transfer medium is an arch-like body. The thermoelectric conversion power generator according to any one of claims 1 to 10, wherein the boundary wall has a flat plate shape. The thermoelectric conversion power generator according to any one of claims 1 to 10, wherein the boundary wall is cylindrical. The thermoelectric conversion module according to any of claims from claim 1, characterized in that it is constituted by a p-type oxide semiconductor and the n-type oxide thermoelectric conversion element made of a semiconductor to claim 12 Thermoelectric conversion power generator. In the oxide thermoelectric conversion element, the p-type oxide semiconductor is one selected from sodium cobalt oxide, calcium cobalt oxide, or calcium bismuth cobalt oxide, and the n-type oxide semiconductor The thermoelectric conversion power generator according to claim 13, which is one selected from zinc oxide, lanthanum nickel oxide, calcium manganese oxide, or strontium titanium oxide.

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