JP4585892B2 - Thermoelectric conversion device and cooling device - Google Patents

Description

  The present invention relates to a thermoelectric conversion device that converts heat to be dissipated when cooling a high-temperature body into electric power, and a cooling device including the thermoelectric conversion device.

  2. Description of the Related Art Conventionally, there is known a thermoelectric conversion device that gives a temperature difference to a junction of different kinds of conductors or semiconductors and extracts electric power generated by the Seebeck effect between a high temperature side and a low temperature side. In this thermoelectric conversion device, the greater the temperature difference between the high temperature side and the low temperature side, the greater the power that can be obtained.

For this reason, the conventional thermoelectric conversion apparatus is attached to the furnace wall of industrial furnaces, such as an incinerator and a melting furnace. In an industrial furnace, since the temperature in the furnace needs to be maintained at a high temperature, the furnace wall is constituted by a heat insulating wall. The thermoelectric conversion device may be provided through a part or all of the thickness of the heat insulating wall or may be provided outside the heat insulating wall (see, for example, Patent Documents 1 and 2).
Japanese Patent Laid-Open No. 10-190073 JP 2002-171776 A

  However, since the conventional thermoelectric conversion devices described in Patent Documents 1 and 2 are applied to industrial furnaces that should maintain a high temperature state, they are premised on the existence of heat insulating walls, and heat to be released to the outside. There was a problem that it could not be used efficiently.

  For example, a continuous furnace needs to be in a sufficiently low temperature state before a high-temperature work after heat treatment is carried out of the apparatus, and includes a cooling chamber for cooling the work. The cooling chamber is covered with a wall surface made of a cooling body such as a water jacket, not a heat insulating wall, in order to cool the work housed therein as quickly as possible.

  For this reason, in a conventional thermoelectric conversion device configured on the premise of the presence of a heat insulating wall, it is not possible to effectively utilize the heat released from the work housed in the cooling chamber to the outside by the cooling body, and from the cooling chamber. In addition to not being able to obtain sufficient power due to the released heat, the cooling performance of the work in the cooling chamber is reduced.

  An object of the present invention is to effectively utilize the heat released from the work housed in the cooling chamber to the outside by the cooling body, and is released from the cooling chamber without reducing the cooling efficiency of the work in the cooling chamber. Another object of the present invention is to provide a thermoelectric conversion device capable of obtaining sufficient electric power by the heat generated, and a cooling device provided with the thermoelectric conversion device.

In order to solve the above problems, a thermoelectric conversion device and a cooling device according to the present invention have a large number of thermoelectric conversion elements arranged in a plane between each of a plurality of insulating layers made of good thermal conductors arranged in parallel to each other. , are brought into close contact with the light absorber in the insulating layer to be a side facing the hot workpiece after the heat treatment a one insulating layer of the two insulating layer exposed to the outside, the hot workpiece after heat treatment to the other insulating layer A cooling body for cooling is closely attached , provided in a cooling section for storing and cooling the high-temperature work after heat treatment, and the electromotive force of the multiple thermoelectric conversion elements is output .

  In this configuration, a plurality of insulating layers made of a good thermal conductor are in close contact with the light absorber and the cooling body, with a large number of thermoelectric conversion elements sandwiched between them. Arranged. When the light absorber is disposed so as to face the high temperature object, the heat released from the high temperature object flows toward the cooling body through the light absorber and the plurality of heat good conductors, and the heat dissipation of the high temperature object is promoted. At this time, electric power is generated in the thermoelectric conversion element sandwiched between each of the plurality of insulating layers due to a temperature difference between the light absorber on the high temperature side and the cooling body on the low temperature side. Therefore, the heat released from the high temperature object is converted into electric power while exhibiting the cooling function of the high temperature object.

  Further, the plurality of insulating layers are three or more insulating layers.

  In this configuration, three or more insulating layers made of a good thermal conductor are in close contact with the light absorber and the cooling body, with a large number of thermoelectric conversion elements sandwiched between them. Arranged. Therefore, a plurality of layered thermoelectric conversion elements are disposed between the light absorber and the cooling body, and generate electric power from heat in different temperature ranges.

  Furthermore, the thermoelectric conversion elements of different materials are arranged in a plane between each of the three or more insulating layers.

  In this configuration, a plurality of layered thermoelectric conversion elements that are arranged between the light absorber and the cooling body and generate electric power from heat in different temperature ranges are made of different materials. Therefore, heat is efficiently converted into electric power in each thermoelectric conversion element layer by appropriately selecting the material of the thermoelectric conversion element arranged between these two insulating layers in accordance with the temperature difference between the two adjacent insulating layers. .

  According to the thermoelectric conversion device and the cooling device of the present invention, a plurality of insulating layers made of a good thermal conductor are arranged in close contact with the light absorber and the cooling body, and a large number of thermoelectric conversion elements are arranged between the insulating layers. By doing so, the heat released from the high temperature object can be converted into electric power while promoting the heat dissipation of the high temperature object arranged facing the light absorber.

  Further, by arranging three or more insulating layers made of a good heat conductor in close contact with the light absorber and the cooling body, and arranging a large number of thermoelectric conversion elements between the insulating layers, the light absorber and the cooling body are arranged. Each of the plurality of layered thermoelectric conversion elements arranged between the two can generate electric power from heat in different temperature ranges. Thereby, thermoelectric conversion can be performed in a state following the performance index curve of the thermoelectric conversion element, and thermoelectric conversion efficiency can be improved.

  In addition, a plurality of layered thermoelectric conversion elements that are arranged between the light absorber and the cooling body and generate electric power from heat in different temperature ranges are made of different materials, so that two adjacent insulating layers The material of the thermoelectric conversion element disposed between these insulating layers can be appropriately selected according to the temperature difference in the above, and the thermoelectric conversion efficiency in each thermoelectric conversion element layer can be further improved.

  FIG. 1 is a cross-sectional view showing a configuration of a cooling device 10 to which a thermoelectric conversion device according to an embodiment of the present invention is applied. The cooling device 10 is used for cooling the semiconductor substrate carried out of the furnace after the heat treatment at the time of manufacturing the semiconductor. The cooling device 10 includes a hollow cooling chamber 12 constituted by the light absorber 11, a cooling jacket 13 covering the outer surface of the cooling chamber 12, and a thermoelectric conversion module disposed between the light absorber 11 and the cooling jacket 13. 14.

  The light absorber 11 has a flat plate shape made of, for example, graphite, and is disposed on a total of six faces facing each other in three directions orthogonal to each other, and forms a hollow cooling chamber 12 inside. In the cooling chamber 12, a semiconductor substrate 21 which is a high-temperature object carried out from a furnace (not shown) is stored. The inner surface of the light absorber 11 faces the semiconductor substrate 21 accommodated in the cooling chamber 12 and absorbs heat released from the semiconductor substrate 21.

  The cooling jacket 13 is a cooling body of the present invention, and is disposed so as to cover the outer surface of the light absorber 11 constituting the cooling chamber 12. The cooling jacket 13 is formed by, for example, a hollow tube serving as a cooling water flow path, and cools the outer surface of the light absorber 11 with cooling water flowing through the hollow tube.

  In the light absorber 11, a temperature difference is generated between the inner surface facing the semiconductor substrate 21 and the outer surface covered with the cooling jacket 13. The heat absorbed by the inner surface of the light absorber 11 propagates through the light absorber 11 toward the outer surface of the light absorber 11 and is absorbed by the cooling water in the cooling jacket 13. As a result, a heat flow in a direction from the inner side surface of the light absorber 11 toward the cooling jacket 13 is formed, and cooling of the semiconductor substrate 21 is promoted.

  The thermoelectric conversion module 14 is disposed between the cooling jacket 13 and at least a part of the outer surface of the light absorber 11. The thermoelectric conversion module 14 has an inner surface in close contact with the outer surface of the light absorber 11 and an outer surface in close contact with the inner surface of the cooling jacket 13. In the example illustrated in FIG. 1, the thermoelectric conversion module 14 is disposed on the upper surface side and the holiday surface side of the cooling chamber 12 in consideration of the direction of heat flow from the semiconductor substrate 21. The thermoelectric conversion module 14 can also be disposed on the entire outer surface of the six light absorbers 11, particularly when a large number of semiconductor substrates placed on a boat are accommodated in the cooling chamber 12.

  The thermoelectric conversion module 14 constitutes the thermoelectric conversion device of the present invention together with the light absorber 11 and the cooling jacket 13. Instead of the cooling jacket 13, another cooling body may be provided.

  Note that the number of semiconductor substrates 21 is not necessarily one, and may be a plurality of semiconductor substrates mounted on a boat, for example.

  FIG. 2 is a cross-sectional view of the thermoelectric conversion module 14. The thermoelectric conversion module 14 includes at least two flat insulating layers 31 and 32 arranged in parallel with each other with a predetermined gap. The insulating layers 31 and 32 are made of a good thermal conductor including a thin film such as a silicon nitride film or an oxide film.

  Between the insulating layer 31 and the insulating layer 32, for example, a thermoelectric conversion layer 37 in which P-type semiconductor elements 33 and N-type semiconductor elements 34 are alternately and repeatedly arranged in a planar shape. The P-type semiconductor element 33 and the N-type semiconductor element 34 are PN-junctioned to constitute one thermoelectric conversion element. A predetermined number of thermoelectric conversion elements among them are connected in series with each other by conductors 35 and 36 of metal thin films.

  In the thermoelectric conversion module 14, one insulating layer 31 is in close contact with the outer surface of the light absorber 11, and the other insulating layer 32 is in close contact with the inner surface of the cooling jacket 13. In the cooling device 10, in the portion where the thermoelectric conversion module 14 is disposed, the heat released from the semiconductor substrate 21 is absorbed by the inner surface of the light absorber 11 and then one insulating layer 31 of the thermoelectric conversion module 14. Then, it is taken away by the cooling water in the cooling jacket 13 via the thermoelectric conversion layer 37 and the other insulating layer 32.

  Therefore, in the thermoelectric conversion module 14, a temperature difference is generated between the one insulating layer 31 and the other insulating layer 32, and electric power corresponding to the temperature difference between both ends is generated in the thermoelectric conversion layer 37. Since the predetermined number of thermoelectric conversion elements are connected in series with each other, the thermoelectric conversion module 14 outputs power at a practical level as the sum of the electromotive forces of the predetermined number of thermoelectric conversion elements.

  The insulating layers 31 and 32 are made of a good thermal conductor, and the heat released from the semiconductor substrate 21 smoothly passes through the thermoelectric conversion module 14 and reaches the cooling jacket 13. Further, part of the heat propagated to the thermoelectric conversion module 14 is converted into electric power in the thermoelectric conversion layer 37 and transmitted to the cooling jacket 13. For this reason, by disposing the thermoelectric conversion module 14 between the light absorber 11 and the cooling jacket 13, the cooling device 10 adversely affects the thermal conductivity between the light absorber 11 and the cooling jacket 13. And the cooling efficiency of the cooling device 10 is not reduced.

  FIG. 3 is a cross-sectional view of a thermoelectric conversion module 40 constituting a thermoelectric conversion device according to another embodiment of the present invention. In the thermoelectric conversion device 40 according to this embodiment, three flat insulating layers 41, 42, 43 are arranged in parallel with each other with a predetermined gap. The insulating layers 41, 42, and 43 are made of a good thermal conductor including a thin film such as a silicon nitride film or an oxide film.

  Between the insulating layer 41 and the insulating layer 42, for example, a thermoelectric conversion layer 61 in which P-type semiconductor elements 44 and N-type semiconductor elements 45 are alternately and repeatedly arranged in a plane is provided. The P-type semiconductor element 44 and the N-type semiconductor element 45 are PN-junction and constitute one thermoelectric conversion element. A predetermined number of these thermoelectric conversion elements are connected in series with each other by conductors 46 and 47 of metal thin films.

  Further, between the insulating layer 42 and the insulating layer 43, for example, a thermoelectric conversion layer 62 in which P-type semiconductor elements 48 and N-type semiconductor elements 49 are alternately and repeatedly arranged in a planar shape. The P-type semiconductor element 48 and the N-type semiconductor element 49 are PN-junction and constitute one thermoelectric conversion element. A predetermined number of these thermoelectric conversion elements are connected to each other in series by metal thin film conductors 50 and 51.

  FIG. 4 is a diagram showing the relationship between the figure of merit Z and the temperature T in the first embodiment of the thermoelectric conversion module 40. In the thermoelectric conversion module 40 according to the first embodiment, the first thermoelectric conversion layer 61 and the second thermoelectric conversion layer 62 are made of the same material.

  The thermoelectric conversion element differs in the figure of merit Z representing the temperature range to be applied and the thermoelectric conversion capability depending on the material. Moreover, even if it is the same material, a figure of merit changes with temperature in many cases. In such a case, by configuring a plurality of thermoelectric conversion layers in the thermoelectric conversion module 40, if the influence of an increase in the distance in the heat flow direction (heat propagation distance) or multilayering in the heat flow direction is ignored, the thermoelectric conversion Efficiency is improved.

For example, when the figure of merit Z of the material used for the thermoelectric conversion element changes as shown by a solid line in FIG. 4 according to the temperature, the temperature on the high temperature side (light absorber 11 side) is T _H and the low temperature side (cooling) the temperature of the jacket 13 side) as T _C, power Z1 obtained when the thermoelectric conversion layer is constituted by a single layer,
Z1∝ {(Z (T _H ) + Z (T _C )) / 2} × (T _H −T _C )
And is proportional to the area of the trapezoid ABCD in FIG.

On the other hand, the electric power Z2 obtained when the thermoelectric conversion layer is composed of two layers is obtained by setting the temperature of the intermediate portion (central insulating layer 42) as T _M.
Z2∝ {(Z (T _H ) + Z (T _M )) / 2} × (T _H −T _M )
_{+ {(Z (T M)} + Z (T C)) / 2} × (T M -T C)
Thus, it is proportional to the sum of the area of the trapezoid AEFD in FIG. 4 and the area of the trapezoid EBCF, and is larger than the electric power Z1 obtained when the thermoelectric conversion layer is formed of a single layer.

  FIG. 5 is a diagram showing the relationship between the figure of merit Z and the temperature T in the second embodiment of the thermoelectric conversion module 40. In the thermoelectric conversion module 40 according to the second embodiment, the first thermoelectric conversion layer 61 and the second thermoelectric conversion layer 62 are made of different materials.

The first thermoelectric conversion layer 61 is formed of a material having the highest figure of merit between the temperature T _H on the high temperature side and the temperature T _{M at the} intermediate portion as indicated by a dashed line 71 in FIG. By configuring the second thermoelectric conversion layer 62 with a material having the highest figure of merit between the temperature T _M at the intermediate portion and the temperature T _C on the low temperature side as shown by a curve 72 indicated by a two-dot chain line, the first thermoelectric conversion layer 62 is formed. Compared with the case where the thermoelectric conversion layer 61 and the second thermoelectric conversion layer 62 are made of the same material, the electric power obtained is increased, and the thermoelectric conversion efficiency is further improved.

  Theoretically, in the first and second embodiments, the electric power obtained increases as the number of thermoelectric conversion layers increases, but due to an increase in heat propagation distance, multilayering in the heat flow direction, and the like. Thermoelectric conversion efficiency and cooling efficiency may be reduced due to the influence. For this reason, the optimal number of thermoelectric conversion layers can be determined according to the use situation of the thermoelectric conversion module 40.

  Further, between the plurality of thermoelectric conversion layers, it is possible to select whether to connect in series or in parallel depending on conditions such as operating temperature conditions, types and configurations of thermoelectric conversion materials, and desired power values. it can.

  Furthermore, in the above embodiment, the case where the thermoelectric conversion device of the present invention is applied to a cooling device provided in a furnace used for manufacturing a semiconductor has been described as an example, but the present invention is not limited thereto. The thermoelectric conversion device of the present invention can be similarly applied to other cooling devices that cool high-temperature objects.

It is sectional drawing which shows the structure of the cooling device to which the thermoelectric conversion apparatus which concerns on embodiment of this invention is applied. It is sectional drawing of the thermoelectric conversion module which comprises the thermoelectric conversion apparatus. It is sectional drawing of the thermoelectric conversion module which comprises the thermoelectric conversion apparatus which concerns on another embodiment of this invention. It is a figure which shows the relationship between the figure of merit and temperature in the 1st Example of the said thermoelectric conversion module. It is a figure which shows the relationship between the figure of merit and temperature in the 2nd Example of the said thermoelectric conversion module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cooling device 11 Light absorber 12 Cooling chamber 13 Cooling jacket 14 Thermoelectric conversion module 31, 32 Insulating layer 33 P-type semiconductor element 34 N-type semiconductor element 35, 36 Conductor

Claims (6)

A plurality of thermoelectric conversion elements are arranged in a plane between each of a plurality of insulating layers made of heat good conductors arranged in parallel to each other, and are one of the two insulating layers exposed to the outside, and after heat treatment A light absorber is closely attached to the insulating layer on the side facing the high temperature workpiece, and a cooling body for cooling the high temperature workpiece after heat treatment is closely attached to the other insulating layer, and the high temperature workpiece after heat treatment is stored and cooled. A thermoelectric conversion device that is provided in a cooling unit for outputting the electromotive force of the numerous thermoelectric conversion elements .   The thermoelectric conversion device according to claim 1, wherein the plurality of insulating layers are three or more insulating layers.   The thermoelectric conversion device according to claim 2, wherein thermoelectric conversion elements made of different materials are arranged in a plane between each of the three or more insulating layers. The inner surface facing the high-temperature work after heat treatment is constituted by a light absorber, covers a hollow cooling chamber for storing and cooling the high-temperature work after heat treatment, and covers the outer surface of the cooling chamber . Two insulating layers exposed to the outside by arranging a plurality of thermoelectric conversion elements in a plane between a cooling jacket for cooling a high-temperature workpiece and a plurality of insulating layers made of a good thermal conductor arranged in parallel to each other one of the insulating layer and a thermoelectric conversion module obtained by close contact with other insulating layer in close contact with the outer surface to the inner surface of the cooling jacket of the light absorber of cooling houses the hot workpiece after heat treatment A cooling device that is provided in a cooling chamber for outputting the electromotive force of the plurality of thermoelectric conversion elements . The cooling device according to claim 4, wherein the plurality of insulating layers are three or more insulating layers. 6. The cooling device according to claim 5, wherein thermoelectric conversion elements made of different materials are arranged in a plane between each of the three or more insulating layers.

Images