JP2009273273A - Thermal power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact thermal power generator which has a small height difference in heating temperature distribution to a plurality of heat generating elements and has a high power generation efficiency. <P>SOLUTION: An exhaust gas flow part 7 for guiding an exhaust gas flow from a radiation type burner 5 comprises: a first guide wall 13 for receiving the radiation heat from the radiation type burner 5, a second guide wall 14 for receiving the exhaust heat, and a third guide wall 15 having an exhaust outlet 22 formed therein. The inside space of the guide walls is gradually reduced from the upstream side to downstream side in the flowing direction of the exhaust gas. Heat generating elements 3 are mounted onto the respective outside surfaces of the guide walls 13, 14, 15. The first guide wall 13 is provided with a first heat collecting part 18, and the second guide wall 14 is provided with a second heat collecting part 21. The maximum projection length of the first heat collecting fin 17 of the first heat collecting part 18 is made shorter than that of the second heat collecting fin 20 of the second heat collecting part 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thermoelectric generator that generates electricity by heating a high temperature side of a thermoelectric generator with heat from a burner.

  As is well known, a thermoelectric generator has a closed circuit formed between an N-type semiconductor and a P-type semiconductor, and an electromotive force is obtained by applying a temperature difference between a high temperature side and a low temperature side. The electric power obtained from the thermoelectric generator can be supplied to other electrical components or stored in a battery or the like.

  2. Description of the Related Art Conventionally, as can be seen in Patent Document 1 below, an apparatus is known that generates power by heating a thermoelectric generator with a burner flame. In this device, the high temperature side of the thermoelectric generator is brought into close contact with a heating plate equipped with fins, and the fins are arranged in the vicinity (directly above) of the flame of the burner, so that the heat of the flame is directly absorbed by the fins for thermoelectric generation. Supplying to the element.

In addition to this, there is known a device that generates heat by the heat of exhaust gas by arranging a thermoelectric generator in an exhaust gas flow path of an internal combustion engine as seen in Patent Document 2 below. In this apparatus, heat generated by the exhaust gas flowing through the exhaust gas channel is absorbed by the fins protruding into the exhaust gas channel, and power is generated by the thermoelectric generator that is in close contact with the fins.
JP-A-11-55975 Japanese Patent Laid-Open No. 11-122960

  However, in the apparatus of Patent Document 1, since the heat generated by the burner flame is directly received by the fins to heat the high temperature side of the thermoelectric elements closely attached to the fins, when a large number of thermoelectric elements are provided, Accordingly, it is necessary to use a burner having a large flame formation area. That is, when a large number of thermoelectric generators are provided in order to obtain more electric power, it is necessary to form a flame capable of heating all the fins that are in close contact with the high temperature side of each thermoelectric generator. For this reason, a burner becomes large-sized and it becomes difficult to comprise an apparatus compactly.

  On the other hand, in the apparatus of Patent Document 2, the heat of the exhaust gas is lower than the heat directly obtained from the flame, and it is necessary to efficiently absorb heat by the fins. The amount of protrusion is relatively large. For this reason, when this configuration is used for direct heating by a flame, the heat load on the tip of the fin becomes extremely large with the heating of the thermoelectric element, which may reduce the durability of the fin, There is an inconvenience that uniform heating distribution cannot be obtained for the thermoelectric generator and the power generation efficiency is lowered.

  In view of the above points, it is an object of the present invention to provide a thermoelectric generator that can be configured compactly and that has a small difference in heating temperature distribution with respect to a plurality of thermoelectric generators and has high power generation efficiency.

  In order to solve the above-described problems, the present invention provides a thermoelectric generator including a combustion heating unit and a plurality of thermoelectric generators that generate electric power using the heat of the combustion heating unit. A radiant burner that forms a flame, and an exhaust flow portion that guides the flow of exhaust gas from the radiant burner, the exhaust flow portion having a shape in which the inside gradually narrows from the upstream side to the downstream side in the flow direction of the exhaust gas And a first guide wall that is located upstream and guides exhaust while receiving radiant heat from the radiant burner, and is connected to the downstream side of the first guide wall and receives exhaust heat. A second guide wall for guiding the exhaust, and a third guide wall provided downstream of the second guide wall to guide the exhaust while receiving the exhaust heat, and having an exhaust outlet at the end. The thermoelectric generator includes the outer surface of the first guide wall and the second guide wall. The outer side surface of the inner wall and the outer side surface of the third guide wall are attached in close contact with the high temperature side, and the first guide wall and the second guide wall protrude toward the inside of the exhaust flow part. A heat collecting portion formed with a plurality of heat collecting fins, wherein the heat collecting portion of the first guide wall has a smaller maximum projecting dimension of the heat collecting fin than the heat collecting portion of the second guide wall; It is characterized by that.

  In the present invention, when the combustion heating means includes a radiant burner, radiant heat and combustion exhaust heat can be obtained from the radiant burner. Therefore, in the exhaust flow part, a heat collecting part is provided on the first guide wall located in a range where the radiant heat from the radiant burner is received, and is attached to the outer surface of the first guide wall by the radiant heat of the radiant burner. The thermoelectric generator is heated. As a result, most of the electromotive force of the thermoelectric generator can be obtained by radiant heat, and the maximum projecting dimension of the heat collecting fins of the heat collecting portion of the first guide wall can be made relatively small, resulting in compactness.

  On the other hand, in the heat collecting part of the second guide wall, heat is absorbed from the combustion exhaust heat of the radiant burner, and the thermoelectric generator attached to the outer surface of the second guide wall is heated. At this time, the heat collection part of the first guide wall has a smaller maximum projecting dimension of the heat collection fin than the heat collection part of the second guide wall, so that the exhaust heat passing through the first guide wall is reduced. Reduction is suppressed. In particular, the radiant burner reduces the exhaust heat with the generation of radiant heat, but the heat collection part of the first guide wall is formed with a small maximum protrusion size of the heat collection fins, and the amount of heat absorbed from the exhaust heat is small. The exhaust is in contact with the heat collecting portion of the second guide wall in a sufficiently high temperature state. As a result, the reduction in exhaust heat due to the generation of radiant heat can be compensated by the heat collection of the heat collection fins with the largest maximum projection size provided in the heat collection portion of the second guide wall, and thus the first guide wall and the second guide By adjusting the size of the maximum protrusion dimension of the heat collecting fin with the wall, the temperature distribution between the first guide wall and the second guide wall can be made uniform.

  Further, since the exhaust flow portion is formed in a shape in which the inside gradually narrows from the upstream side to the downstream side in the flow direction of the exhaust gas, the speed of the combustion exhaust gas flowing along the third guide wall through the second guide wall is increased. To increase. The third guide wall can be sufficiently heated by the combustion exhaust gas having an increased flow velocity, and the first guide wall can be narrowed (narrowed) to adjust the flow velocity of the combustion exhaust gas appropriately. The temperature distribution of the guide wall and the second guide wall and the third guide wall can be made uniform. This also eliminates the need for the heat collection fins provided in the first guide wall and the second guide wall in the third guide wall, and suppresses the pressure loss of the combustion exhaust at the exhaust outlet and performs combustion. A smooth flow of exhaust can be obtained.

  Thus, according to the present invention, it is possible to make the temperature distribution uniform along the flow direction of the exhaust gas even if the thermoelectric generator is disposed on the outer surface of each guide wall of the exhaust gas flow portion. Therefore, it is possible to provide a thermoelectric generator having high power generation efficiency by reducing the difference in heating temperature distribution between the thermoelectric generators. Further, if the temperature of the heat collecting fins becomes higher than necessary due to the small protruding size of the heat collecting fins receiving radiant heat at the first guide wall and the large protruding size of the heat collecting fins receiving exhaust heat at the second guide wall. Therefore, it is possible to prevent the durability of the heat collecting fins from being lowered. Furthermore, since the temperature distribution from the first guide wall to the third guide wall can be made uniform using radiant heat and exhaust heat, a plurality of thermoelectric generators can be heated without increasing the size of the burner as in the prior art. Can be configured compactly.

  Further, in the present invention, a plurality of the thermoelectric generators are arranged at predetermined intervals in the transverse direction intersecting the flow direction of the exhaust for each guide wall of the exhaust flow portion, Corresponding to each thermoelectric generation element, a plurality of them are arranged at predetermined intervals in the lateral direction intersecting the flow direction of the exhaust gas.

  The plurality of thermoelectric generators can be arranged not only along the flow direction of the exhaust gas (that is, along the vertical direction) but also in the horizontal direction, so that more electric power can be obtained. At this time, if the heat collecting part is continuously provided along the arrangement direction of the thermoelectric generators arranged in the lateral direction, each guide wall has a temperature due to heat absorption at a position where the high temperature side of the thermoelectric generator is in close contact. The temperature is increased by the amount of heat absorption at the interval between the adjacent thermoelectric generators in the horizontal direction, so that a uniform temperature distribution in the horizontal direction cannot be obtained for each guide wall.

  Therefore, in the present invention, the plurality of heat collecting portions are arranged at predetermined intervals in the lateral direction so as to correspond to the positions where the high temperature portions of the respective thermoelectric generators are in close contact with each other. Increases the amount of heat collected at the position where the parts are in close contact. In this way, local heat absorption by each thermoelectric generator can be supplemented by heat collection by the heat collector, and at the same time, temperature rise at the interval between adjacent thermoelectric generators in the lateral direction can be suppressed. The temperature distribution can be made uniform in the horizontal direction. Therefore, according to the present invention, the difference in heating temperature distribution can be reduced even for thermoelectric generators arranged in the horizontal direction, and the power generation efficiency can be further improved.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory view showing a configuration of the thermoelectric generator of the present embodiment with a part thereof removed, FIG. 2 is an explanatory perspective view showing an exhaust flow part with one side wall removed, and FIG. 3 is one first guide. 4 is an explanatory cross-sectional view of the wall, FIG. 4 is an explanatory cross-sectional view of one of the second guide walls, FIG. 5A is an explanatory view showing temperature measurement points and their temperatures on the first guide wall of the present embodiment, FIG. 5B is an explanatory diagram showing temperature measurement points and their temperatures on the first guide wall of the comparative example.

  As shown in FIG. 1, the thermoelectric generator 1 of this embodiment includes a combustion heating unit 2 and a thermoelectric generator 3. In the thermoelectric generator 3, an electromotive force is obtained by giving a temperature difference between the high temperature side 3a and the low temperature side 3b, and the high temperature side 3a is heated by the combustion heating means 2. A cooling block 4 to which a cooling medium is supplied is closely attached to the low temperature side 3b of the thermoelectric generator 3. The electric power obtained from the thermoelectric generator 3 is sent to electric parts, storage batteries, etc., not shown.

  As shown in FIG. 1, the combustion heating means 2 includes a radiant burner 5 that generates radiant heat and combustion exhaust, a burner support 6 that accommodates and supports the radiant burner 5, and the burner support 6. An exhaust flow portion 7 is provided that extends upward and guides the flow of combustion exhaust generated from the radiant burner 5 in the upward direction.

  As shown in FIG. 1, the radiant burner 5 is provided with a ceramic combustion plate 9 on the upper opening surface of the burner body 8, and fuel gas and primary air supplied into the burner body 8 through a mixing tube 10. The air-fuel mixture is ejected from a number of flame holes formed in the combustion plate 9 and burned.

  As shown in FIGS. 1 and 2, the exhaust flow section 7 includes a pair of first side walls 11 that face each other and a pair of second side walls 12 that face each other in a direction orthogonal to the opposing direction of the first side walls 11. The combustion exhaust generated from the radiant burner 5 flows in the interior surrounded by the first side wall 11 and the second side wall 12. The first guide wall 13, the second guide wall 14, and the third guide wall 15 are provided on the first side walls 11 in order from below.

  Both the first guide walls 13 are inclined in the direction in which the upper ends approach each other, and the interval between the first guide walls 13 is gradually narrowed so that the radiant heat from the radiant burner 5 can be received on the inner surfaces of the first guide walls 13. Yes. A plurality of (two in the present embodiment) thermoelectric generators 3 are attached to the outer surfaces of the first guide walls 13 at predetermined intervals in the transverse direction intersecting the exhaust flow direction. One close contact portion 16 is provided. Each first close contact portion 16 is in close contact with the high temperature side 3 a of each thermoelectric generator 3.

  Further, as shown in FIG. 3, a plurality of first heat collecting fins 17 projecting toward the inside are formed on the inner side surfaces of the first guide walls 13, and the first heat collecting fins 17 are formed. The first heat collecting portion 18 is formed by the portion. The first heat collecting section 18 is formed in a plurality of portions with intervals where the first heat collecting fins 17 are not formed. Each first heat collecting portion 18 is located at a position corresponding to each first contact portion 16, and is formed over a range slightly larger than the area of the first contact portion 16.

  As shown in FIGS. 1 and 2, the lower ends of the second guide walls 14 are connected to the upper end of the first guide wall 13. Both the second guide walls 14 are also inclined in the direction in which the upper ends approach each other, and the interval between the two is gradually narrowed, but the radiant heat from the radiant burner 5 received on the inner surface side is smaller than both the first guide walls 13. A plurality of (two in the present embodiment) thermoelectric generators 3 are attached to the outer surfaces of the second guide walls 14 at predetermined intervals in the transverse direction intersecting the flow direction of the exhaust gas. Two close contact portions 19 are provided. The high temperature side 3 a of each thermoelectric generator 3 is in close contact with each second close contact portion 19.

  Further, as shown in FIG. 4, a plurality of second heat collecting fins 20 projecting toward the inside are formed on the inner side surfaces of the second guide walls 14, and the second heat collecting fins 20 are formed. A second heat collecting portion 21 is formed by the portion. The second heat collecting portion 21 is formed in a plurality of portions with intervals between portions where the second heat collecting fins 20 are not formed. Each second heat collecting portion 21 is located at a position corresponding to each second close contact portion 19 and is formed over a range slightly larger than the area of the second close contact portion 19.

  As shown in FIGS. 3 and 4, the maximum protrusion dimension a of the first heat collection fin 17 is smaller than the maximum protrusion dimension b of the second heat collection fin 20.

  As shown in FIGS. 1 and 2, the lower ends of the third guide walls 15 are connected to the upper end of the second guide wall 14. Both the third guide walls 15 extend upward substantially parallel to each other, and an exhaust outlet 22 is formed at the upper end. A plurality of (two in the present embodiment) thermoelectric generators 3 are attached to the outer surfaces of the third guide walls 15 at predetermined intervals in the transverse direction intersecting the flow direction of the exhaust gas. Three contact portions 23 are provided. The high temperature side 3 a of each thermoelectric generator 3 is in close contact with each third close contact portion 23. Further, the inner side surfaces of the third guide walls 15 are formed to be substantially smooth so that the combustion exhaust gas can flow smoothly inside. In addition, as long as the flow of combustion exhaust gas can be obtained smoothly, for example, heat collecting fins that slightly protrude from the inner side surfaces of the third guide walls 15 may be provided.

  Next, the operation of the thermoelectric generator 1 configured as described above will be described. When the radiant burner 5 burns, the radiant burner 5 generates radiant heat and combustion exhaust. The radiant heat of the radiant burner 5 hits the first guide wall 13 inclined so as to receive this radiant heat, and the heat passes through the first contact portion 16 and heats the high temperature side 3a of the thermoelectric generator 3. At the same time, the combustion exhaust of the radiant burner 5 rises in contact with the first heat collection fins 17 of the first heat collection unit 18, and a part of the heat of the combustion exhaust is collected by the first heat collection fins 17. Thereby, the high temperature side 3a of the thermoelectric generator 3 is heated by the radiant heat and the combustion exhaust heat. The thermoelectric generator 3 has a temperature difference between the high temperature side 3a and the low temperature side 3b due to the low temperature side 3b being cooled by the cooling block 4, thereby generating electric power. At this time, since the first heat collecting fins 17 have a relatively small projecting dimension, the heat of the combustion exhaust is not taken away excessively, and the second guide wall 14 is kept in a state where the temperature reduction of the combustion exhaust is suppressed. Head for.

  In the second guide wall 14, the combustion exhaust rises while being in contact with the second heat collection fins 20 of the second heat collection section 21, and the heat of the combustion exhaust is collected by the second heat collection fins 20, so that the second The high temperature side of the thermoelectric generator 3 that is in close contact with the close contact portion 19 is heated. Since the second guide wall 14 is far from the first guide wall 13 because the distance from the radiant burner 5 is far from the radiant heat of the radiant burner 5, the second heat collecting fin 20 is equivalent to the first heat collecting fin 20. Since the projecting dimensions are larger than those of the fins 17, it is possible to sufficiently collect heat from the combustion exhaust. As a result, the temperature distribution between the first guide wall 13 and the second guide wall 14 is made uniform, and there is a difference in height between the thermoelectric generator 3 of the first contact portion 16 and the thermoelectric generator 3 of the second contact portion 19. Less heating temperature distribution.

  The combustion exhaust gas flowing through the second guide wall 14 passes between the third guide walls 15 at an increased flow velocity due to the gradually decreasing distance between the first guide wall 13 and the second guide wall 14. In the third guide wall 15, a large amount of combustion exhaust passes in a short time, so that a lot of heat is collected from the combustion exhaust, and the heat passes through the third contact portion 23 and passes through the high temperature side 3 a of the thermoelectric generator 3. Heat. At this time, the temperature of the combustion exhaust passing between the third guide walls 15 is lowered to some extent by passing through the first heat collecting fins 17 and the second heat collecting fins 20. There is no overheating. In addition, since it is not necessary to provide heat collecting fins on the inner side surfaces of the third guide walls 15, pressure loss can be suppressed. Therefore, the temperature distribution among the first guide wall 13, the second guide wall 14, and the third guide wall 15 is made uniform, and between the contact portions 16, 19, and 23 disposed along the exhaust flow direction. The heating temperature distribution with little difference in height can be obtained.

  Here, as a result of measuring the temperature of each of the contact portions 16, 19, and 23, the inventor sets the lowest temperature when the target heating temperature by combustion exhaust gas is 650 ° C. It is 630 ° C., 600 ° C., and 620 ° C. in the order of the two close contact portions 19 and the third close contact portion 23, and it is confirmed that a heating temperature distribution with a small difference in height is obtained between the close contact portions 16, 19, and 23. did it. In addition, in order to compare with the structure of this embodiment, the inner side surface was smoothly formed from the first guide wall 13 to the third guide wall 15 without providing the first heat collection unit 18 and the second heat collection unit 21. When the same temperature measurement was performed with a thing, it became 550 degreeC, 500 degreeC, and 660 degreeC in order of the 1st contact part 16, the 2nd contact part 19, and the 3rd contact part 23, The structure of this embodiment It was found that good heating temperature distribution can be obtained.

  Moreover, in the 1st guide wall 13 and the 2nd guide wall 14, the 1st heat collecting part 18 and the 2nd heat collecting part 21 respond | correspond to the thermoelectric generator 3 arranged side by side with predetermined spacing. Both are formed side by side with a predetermined interval. According to this, the difference in elevation of the heating temperature distribution can be reduced even for the thermoelectric generators 3 arranged in the horizontal direction.

  That is, as shown in FIGS. 5 (a) and 5 (b), the present inventor has the outer surface of the first guide wall 13 of the present embodiment when the target heating temperature by combustion exhaust is 650 ° C. The heating temperatures at a plurality of temperature measurement points A to G were measured and compared with the outer surface of the first guide wall 31 of Comparative Example 30. Although the 1st guide wall 31 of the comparative example 30 is provided with the 1st heat collection part 32 in which the 1st heat collection fin of the same shape as the 1st heat collection part 18 of this embodiment was formed, this 1st heat collection part 32 is continuous along the contact portions 33 of the thermoelectric generators 6 arranged side by side, and does not form an interval corresponding to each thermoelectric generator 6. As a result, as shown in FIG. 5B, in the first guide wall 31 of the comparative example 30, the portion with the highest heating temperature (measurement point D) and the portion with the lowest heating temperature (measurement points A and G) As shown in FIG. 5A, the first guide wall 13 of the present embodiment has the highest heating temperature (measurement point D) and the highest heating temperature. The temperature difference from the lower part (measurement points A and G) was 50 ° C., and it was confirmed that the difference in heating temperature distribution was small with respect to the thermoelectric generators 3 arranged in the horizontal direction.

  In addition, as shown in FIG. 2, the exhaust flow part 7 of this embodiment has the boundary of each guide wall 13,14,15 bent, However, Each guide wall 13,14,15 is made to continue linearly. May be configured.

  In addition, the exhaust flow portion 7 of the present embodiment is formed in a rectangular tube shape, and the guide walls 13, 14, and 15 that face each other in a pair narrow the facing interval, so that the exhaust flow portion 7 is downstream from the upstream side in the exhaust flow direction. Although the inside is gradually narrowed toward the side, the exhaust flow part can also be formed in a cylindrical shape, although not shown. However, the exhaust flow portion 7 of the present embodiment is formed in a rectangular tube shape, so that the interior from the upstream side to the downstream side is reduced without reducing the mounting area of the thermoelectric generator 3 on each guide wall 13, 14, 15. It is advantageous in that it can be made narrower and can be made compact while having a large number of thermoelectric generators 3.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which removes the part and shows the structure of the thermoelectric generator of one Embodiment of this invention. The explanatory perspective view which removes the one side wall and shows an exhaust_gas | exhaustion flow part. An explanatory cross-sectional view of one first guide wall. Explanatory cross-sectional view of one second guide wall. (A) is explanatory drawing which shows the temperature measurement point in the 1st guide wall of this embodiment, and its temperature, (b) is explanatory drawing which shows the temperature measurement point in the 1st guide wall of a comparative example, and its temperature.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Thermoelectric generator, 2 ... Combustion heating means, 3 ... Thermoelectric power generation element, 3a ... High temperature side, 5 ... Radiation type burner, 7 ... Exhaust flow part, 9 ... Combustion plate, 13 ... 1st guide wall, 14 ... 1st 2 guide walls, 15 ... third guide wall, 17, 20 ... heat collecting fins, 18, 21 ... heat collecting section, 22 ... exhaust outlet.

Claims (2)

In a thermoelectric generator comprising a combustion heating means and a plurality of thermoelectric generators that generate electricity by the heat of the combustion heating means,
The combustion heating means includes a radiant burner that forms a flame on the surface of the combustion plate, and an exhaust flow part that guides the flow of exhaust gas from the radiant burner,
The exhaust flow portion is formed in a shape in which the inside gradually narrows from the upstream side to the downstream side in the flow direction of the exhaust gas, and is located upstream, and guides the exhaust while receiving radiant heat from the radiant burner. One guide wall, a second guide wall that is provided downstream of the first guide wall and guides exhaust gas while receiving exhaust heat, and a second guide wall that is provided downstream of the second guide wall and receives exhaust heat A third guide wall that guides the exhaust while having an exhaust outlet formed at the end,
Each thermoelectric generator is attached with the high-temperature side in close contact with the outer surface of the first guide wall, the outer surface of the second guide wall, and the outer surface of the third guide wall,
The first guide wall and the second guide wall include a heat collecting part in which a plurality of heat collecting fins protruding toward the inside of the exhaust flow part are formed,
The thermoelectric generator according to claim 1, wherein the heat collection portion of the first guide wall has a smaller maximum projecting dimension of the heat collection fin than the heat collection portion of the second guide wall. A plurality of the thermoelectric generators are arranged at predetermined intervals in the transverse direction intersecting the flow direction of the exhaust for each guide wall of the exhaust flow portion,
2. The thermoelectric generator according to claim 1, wherein a plurality of the heat collecting portions are arranged at predetermined intervals in a lateral direction intersecting a flow direction of exhaust gas corresponding to each thermoelectric generator. .

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