JP6096562B2 - Thermoelectric generator and ship equipped with the same - Google Patents

Description

  The present invention relates to a thermoelectric generator and a ship equipped with the same.

  Conventionally, in a ship such as a tanker or a transport ship, the amount of power consumed by various auxiliary machines, cargo handling devices, lighting, air conditioning, and other equipment is enormous. There are provided a plurality of diesel generators (hereinafter referred to as Patent Document 1, etc.) that combine a power generation engine (hereinafter referred to as a power generation engine) and a generator that generates power by driving the power generation engine. Waste heat released from the ship's main diesel engine (hereinafter referred to as the main engine) is recovered to generate high-temperature and high-pressure steam that is used as a power source for power generation or as a heat source for hot water supply. Waste heat recovery systems are known (see, for example, Patent Document 2).

JP 2006-341742 A JP 2007-1339 A

  Efficiently recovering waste heat from various engines as electrical energy is important not only for reducing the energy cost of various engines, but also for reducing the environmental burden. However, the techniques described in Patent Documents 1 and 2 do not consider recovering waste heat from the power generation engine as electric energy. Even if the waste heat recovery system for the main engine is applied to each power generation engine, not only will the structure of the waste heat recovery system increase as a whole, but the structure will also become complicated and the number of manufacturing steps and parts will increase. Manufacturing costs will increase.

  As a measure for solving the above-mentioned problems, it is possible to apply a thermoelectric power generation technology, which is one of energy conversion technologies with a low environmental load, to a waste heat recovery system for a power generation engine. Thermoelectric power generation technology uses the Seebeck effect that generates an electromotive force by giving a temperature difference to both ends of a thermoelectric module made of metal, semiconductor, or the like, and can directly convert thermal energy into electrical energy. The inventors of the present application have paid attention to such a thermoelectric power generation technique, and have made further improvements to complete the present invention.

The invention of claim 1 relates to a thermoelectric power generation apparatus, comprising: a pipe through which a heat medium flows; and a plurality of thermoelectric units having a plate-like thermoelectric module that generates power by a temperature difference between a low temperature side and a high temperature side, In a thermoelectric generator that projects heat collection fins provided on the high temperature side of each thermoelectric module into the pipe and heats each heat collection fin with the heat medium, the high temperature side of each thermoelectric module and the heat collection fin In between, a non-liquid cooling type temperature control member that suppresses heat transfer to the high temperature side of each thermoelectric module is interposed, and the temperature control member is a metal plate with a known contact heat resistance value and high reproducibility. The ceramic plates or combinations thereof are laminated to adjust the reachable temperature on the high temperature side .
According to a second aspect of the present invention, in the thermoelectric generator according to the first aspect, the temperature control member is formed by alternately laminating steel plates and alumina plates.

According to a third aspect of the present invention, in the thermoelectric power generator according to the first or second aspect , a material mainly composed of bismuth and tellurium is used as the material used for each of the thermoelectric modules.

  The invention of claim 4 relates to a ship, and the thermoelectric power generator according to any one of claims 1 to 3 is arranged in an exhaust path of an internal combustion engine mounted in a ship body.

  According to the present invention, it is provided with a pipe through which a heat medium flows and a plurality of thermoelectric units having a plate-like thermoelectric module that generates electricity by a temperature difference between a low temperature side and a high temperature side, and the high temperature of each thermoelectric module is included in the pipe. In the thermoelectric generator that projects the heat collecting fins provided on the side and heats the heat collecting fins with the heat medium, between the high temperature side of the thermoelectric modules and the heat collecting fins, Since a non-liquid cooling type temperature control member that suppresses heat transfer to the high temperature side is interposed, when the reachable temperature on the high temperature side of each thermoelectric module is limited, the temperature control member causes the high temperature side of each thermoelectric module to Therefore, the thermoelectric power generation by each thermoelectric module can be executed in the most efficient temperature range. For this reason, the thermoelectric power generation efficiency of each thermoelectric module can be improved. Variations in heat transfer to the high temperature side of each thermoelectric module can be suppressed by the temperature control member, and heat transfer performance can be improved. In addition, since the thermal deformation, thermal shock, and thermal alteration that the temperature and flow rate of the exhaust gas that is the heat medium give to the high temperature side of each thermoelectric module can be mitigated, the thermoelectric module can be reliably prevented from being damaged.

It is the whole ship side view in an embodiment. It is II-II front sectional drawing of FIG. It is a schematic front view which shows the thermoelectric generator provided in the exhaust path. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a vertical sectional view taken along line VV in FIG. 3. It is an expansion schematic of a thermoelectric unit.

  Hereinafter, an embodiment embodying the present invention will be described based on the drawings (FIGS. 1 to 6) when applied to a thermoelectric generator mounted on a ship.

  As shown in FIG. 1, a ship 1 according to the embodiment includes a hull 2, a cabin 3 (bridge) provided on the stern side of the hull 2, a funnel 4 (chimney) disposed behind the cabin 3, and a hull 2. A propeller 5 and a rudder 6 provided at the rear lower part are provided. In this case, the skeg 8 is integrally formed on the bottom 7 of the stern side. A propeller shaft 9 that rotationally drives the propeller 5 is supported on the skeg 8. A hold 10 is provided on the bow side and the center in the hull 2. An engine room 11 is provided on the stern side in the hull 2.

  In the engine room 11, a main engine 21 (diesel engine in the embodiment) and a speed reducer 22 that are driving sources of the propeller 5, and a power generation device 23 for supplying electric power to the electrical system in the hull 2 are arranged. Yes. The propeller 5 is rotationally driven by the rotational power from the main engine 21 via the speed reducer 22. The interior of the engine room 11 is partitioned vertically by an upper deck 13, a second deck 14, a third deck 15, and an inner bottom plate 16. In the embodiment, the main engine 21 and the speed reducer 22 are installed on the inner bottom plate 16 at the lowermost stage of the engine room 11, and the power generator 23 is installed on the third deck 15 at the middle stage of the engine room 11. Although detailed illustration is omitted, the hold 10 is divided into a plurality of sections.

  As shown in FIG. 2, the power generation apparatus 23 includes a plurality of diesel generators 24 (implemented with a combination of a power generation engine 25 (diesel engine in the embodiment) and a power generator 26 that generates power by driving the power generation engine 25). 3 in the form). The diesel generator 24 is basically configured to operate efficiently in accordance with the required power amount in the hull 2. For example, all the diesel generators 24 are operated at the time of sailing or the like that consumes a large amount of power, and an arbitrary number of diesel generators 24 are operated at the time of berth where the power consumption is relatively low.

  The generated power generated by the operation of each generator 26 is supplied to the electrical system in the hull 2. Although not shown in detail, a power transducer is electrically connected to each generator 26. The power transducer detects power generated by each generator 26.

  Each power generation engine 25 is connected to an intake path (not shown) for air intake and an exhaust path 27 for exhaust gas discharge. The air taken in through the intake path is sent into each cylinder of the power generation engine 25 (inside the cylinder in the intake stroke). When the compression stroke of each cylinder is completed, the fuel sucked up from the fuel tank is pumped into the combustion chamber of each cylinder by the fuel injection device, and the expansion stroke accompanying the self-ignition combustion of the air-fuel mixture is performed by each combustion chamber.

  The exhaust passage 27 of each power generation engine 25 extends to the funnel 4 and directly communicates with the outside. As described above, since there are three power generation engines 25, there are three exhaust paths 27. A silencer 28 is provided on the downstream side of each exhaust path 27 to attenuate the exhaust sound of the exhaust gas discharged from the power generation engine 25. A thermoelectric generator that converts waste heat (heat of exhaust gas, which is a heat medium) from the power generation engine 25 into electrical energy, in the middle of each exhaust path 27 (specifically, upstream of the silencer 28). 30 is provided. Exhaust gas discharged from each power generation engine 25 is discharged outside the ship 1 through the exhaust path 27, the thermoelectric power generation device 30, and the silencer 28. The thermoelectric generator 30 is disposed on the upper side of the engine room 11. In the embodiment, the thermoelectric generator 30 is installed on the second deck 14 on the upper stage of the engine room 11.

  As shown in FIGS. 3 to 5, the thermoelectric power generator 30 provided in the middle of each exhaust path 27 includes a substantially cylindrical pipe 31 through which exhaust gas as a heat medium flows, a low temperature side and a high temperature side. And a plurality of thermoelectric units 32 having a plate-like thermoelectric module 33 that generates electric power according to the temperature difference, and the high temperature side of each thermoelectric module 33 is configured to be heated with exhaust gas. The upstream side exhaust pipe 34 and the downstream side exhaust pipe 35 that constitute the exhaust path 27 are located on both sides of the pipe 31 of the thermoelectric generator 30 so as to be distributed. An upstream flange 36 protruding in the outer peripheral direction is attached to the opening end of the upstream exhaust pipe 34 on the exhaust downstream side. A downstream flange 37 protruding in the outer peripheral direction is attached to the opening end of the downstream exhaust pipe on the exhaust upstream side. A connecting flange 38 that protrudes in the outer peripheral direction is attached to the opening ends of both ends of the pipe 31 in the exhaust direction.

  A pipe 31 is interposed between the upstream side exhaust pipe 34 and the downstream side exhaust pipe 35. The upstream flange 36 and the connecting flange 38 on the upstream side of the exhaust are brought into contact with each other via a gasket (not shown), and both the flanges 36 and 38 are fastened with a plurality of sets of bolts 39 and nuts 40. Further, the downstream flange 37 and the connecting flange 38 on the exhaust downstream side are abutted with each other via a gasket (not shown), and both flanges 37 and 38 are fastened with a plurality of sets of bolts 39 and nuts 40. As a result, the upstream side exhaust pipe 34, the pipe 31, and the downstream side exhaust pipe 35 are detachably connected. Exhaust gas as a heat medium discharged from each power generation engine 25 flows from the upstream exhaust pipe 34 to the downstream exhaust pipe 35 through the pipe 31 of the thermoelectric generator 30 in the exhaust path 27.

  As shown in FIG. 4, the pipe 31 of each thermoelectric generator 30 is formed in a polygonal cross section. The pipe 31 according to the embodiment has an octagonal cross-sectional shape in which a corner portion of a cylindrical body having a quadrangular cross-section is chamfered. In other words, the pipe 31 of the embodiment has a cylindrical shape with an octagonal cross section in which the wide flat surface portions 41 and the chamfered portions 42 are alternately connected. A thermoelectric unit 32 group is attached to each flat surface portion 41 of the pipe 31.

  In this case, rectangular opening holes 43 penetrating in the plate thickness direction are formed in each flat portion 41 in a matrix form of two rows parallel in the exhaust direction. A mounting frame 44 surrounding the outer peripheral side of each opening hole 43 is provided on the outer surface side of each flat portion 41 by welding or the like. The mounting frame 44 of the embodiment is formed in an 8-character shape so as to surround the outer peripheral side of two opening holes 43 adjacent in the circumferential direction. And the thermoelectric unit 32 is attached to each attachment frame 44 so that each opening hole 43 of the plane part 41 may be plugged up.

  In the embodiment, two rows of parallel opening holes 43 are formed in each plane portion 41, and a plurality of attachment frames 44 are fixed to one plane portion 41. The thermoelectric unit 32 is mounted on the mounting frame 44. Therefore, the thermoelectric generator 30 is constituted by the thermoelectric units 32 arranged on the four planes.

  As shown in detail in FIG. 6, each thermoelectric unit 32 includes a thermoelectric module 33 that generates electricity by a temperature difference between a low temperature side and a high temperature side, a cooling case 45 as a low temperature side member, and a heat collecting fin as a high temperature side member. 46.

  The cooling case 45 has a passage through which a coolant such as cooling water is circulated. The cooling case 45 of each thermoelectric unit is connected to, for example, a heat exchanger of each power generation engine 25 via a cooling pipe (not shown). The cooling case 45 is cooled by causing the refrigerant from the heat exchanger to flow through the passage in the cooling case 45.

The thermoelectric module 33 is formed by electrically connecting two types of semiconductors of p-type and n-type made of, for example, Bi ₂ Te ₃ or the like alternately with electrodes, and insulating between adjacent electrodes. Each thermoelectric module 33 is connected in parallel or in series, and is connected to an electrical load via electrical wiring. An electromotive force is generated in the thermoelectric module 33 by cooling one wide side surface of the thermoelectric module 33 with the refrigerant in the cooling case 45 and heating the other wide side surface of the thermoelectric module 33 with heat from the heat collecting fins 46 in contact with the exhaust gas. Is generated and the generated power is taken out.

  The heat collecting fins 46 are formed by projecting a large number of fin portions 48 on a base 47 having a wide rectangular flat plate covering a portion corresponding to the opening hole 43 in the mounting frame 44. The heat collection fins 46 of the embodiment are formed of a highly heat conductive ceramic such as AlN or SiC in addition to a metal having a good heat conductivity such as an aluminum alloy, a copper alloy, or stainless steel. A rectangular flat plate-shaped temperature control member 49 is interposed between the thermoelectric module 33 and the heat collecting fins 46. The temperature control member 49 of the embodiment is of a non-liquid cooling type that suppresses heat transfer from the heat collecting fins 46 to the high temperature side of the thermoelectric module 33, and has a plurality of layers of metal plates, ceramic plates, or a combination thereof. It is composed of a laminated body. In this case, steel plates and alumina plates are alternately laminated and integrated as a temperature control member 49 by bolt fastening or the like. And the temperature control member 49 suppresses the heat transfer from the heat collection fin 46 to which the exhaust gas hits, for example, about 350 to 400 ° C. on the average to the high temperature side of the thermoelectric module 33, and sets the temperature reached on the high temperature side of the thermoelectric module. For example, it is configured to suppress to 200 ° C. or lower.

  Here, since the steel plate and the alumina plate are members having known contact thermal resistance values and high reproducibility, it is easy to adjust the reachable temperature on the high temperature side of the thermoelectric module 33 depending on the surface roughness and the number of laminated layers. Can be done. For this reason, the laminated body (temperature control member 49) which performs the thermoelectric power generation by the thermoelectric module 33 in the most efficient temperature range can be designed easily, and the thermoelectric power generation efficiency can be improved. As can be seen from this point, it is desirable that the temperature control member 49 itself or the material of the laminated plates has a known contact thermal resistance value. The temperature control member 49 does not necessarily have a laminated structure. If the contact thermal resistance value is known and the contact thermal resistance is highly reproducible, the reachable temperature on the high temperature side of the thermoelectric module 33 is adjusted at the time of design. It goes without saying that it is possible.

  When attaching each thermoelectric unit 32 to the pipe 31, the fin portion 48 of the heat collection fin 46 of each thermoelectric unit 32 is inserted into the opening hole 43 through the attachment frame 44, and the heat collection fin 46 is inserted into the pipe 31. The fin part 48 is protruded. Then, the base 47 of the heat collecting fin 46 is overlapped with the mounting frame 44 and fastened with bolts. When the exhaust gas flows into the pipe 31, the exhaust gas comes into contact with the fin portions 48 in the pipe 31 of each heat collection fin 46, and waste heat (heat of the exhaust gas) is collected by the heat collection fins 46. By the heat transfer from each heat collection fin 46, the other wide side surface (high temperature side) of each thermoelectric module 33 is heated. A refrigerant flows into each cooling case 45 to cool one wide side surface (low temperature side) of each thermoelectric module 33. As a result, a temperature difference occurs between the low temperature side and the high temperature side of each thermoelectric module 33, and an electromotive force is generated in each thermoelectric module 33 to generate power.

  When configured as described above, in limiting the reachable temperature on the high temperature side of each thermoelectric module 33, it becomes possible to adjust the reachable temperature on the high temperature side of each thermoelectric module 33 by the temperature control member 49. Thermoelectric power generation by the module 33 can be performed in the most efficient temperature range. For this reason, the thermoelectric power generation efficiency of each thermoelectric module 33 can be improved. Variations in heat transfer to the high temperature side of each thermoelectric module 33 can be suppressed by the temperature control member 49, and heat transfer performance can be improved. In addition, since the thermal deformation, thermal shock, and thermal alteration given to the high temperature side of the thermoelectric module 33 by the temperature or flow rate change of the exhaust gas that is the heat medium can be mitigated, the thermoelectric module 33 can be reliably prevented from being damaged. Furthermore, since a material mainly composed of bismuth and tellurium is used as the material used for each thermoelectric module 33, the bismuth-tellurium-based thermoelectric module 33 that is used at a relatively low temperature and is widely marketed is used. Due to the presence of the control member 49, it can also be used in the exhaust path 27 of an internal combustion engine such as the power generation engine 25 or the main engine 21, for example. In addition, since the temperature control member 49 of the embodiment is configured by a laminated body in which a plurality of layers are laminated with a metal plate, a ceramic plate, or a combination thereof, each thermoelectric module 33 has a simple configuration without cost. Variation of heat transfer to the high temperature side can be reliably suppressed.

  As shown in FIGS. 4 and 5, in the pipe 31, a shield 50 as a heat medium guide member that sends exhaust gas, which is a heat medium, to each heat collection fin 46 side is appropriately separated from the inner peripheral surface of the pipe 31. Arranged. The shield 50 according to the embodiment plays a role of narrowing the cross-sectional area inside the pipe 31 and forms the base of the shield 50 in a square cross section. The outer peripheral surfaces of the four flat portions 51 at the base of the shield 50 are opposed to the inner peripheral surfaces of the four flat portions 41 of the pipe 31. The piping 31 and the shielding body 50 are integrally connected via a plurality of bridge bodies 53 that are appropriately separated from each other in a narrow passage 52 between the pipes 31 and 50. That is, the pipe 31 and the shield 50 have a double cylinder structure. The inner peripheral surface of each flat surface portion 41 of the pipe 31 and the outer peripheral surface of the flat portion 51 of the shield 50 base that faces this are aligned in parallel along the exhaust direction. The fin portions 48 of the respective heat collecting fins 46 are positioned between the inner peripheral surface of each flat surface portion 41 of the pipe 31 and the outer peripheral surface of the flat portion 51 of the shield 50 base that faces the flat surface portion 41.

  In this case, since the inner peripheral surface of each flat surface portion 41 of the pipe 31 and the outer peripheral surface of the flat portion 51 of the shield 50 base opposite thereto are arranged in parallel along the exhaust direction, the collection of each thermoelectric unit 32 is arranged. When making the projection length of the heat fin 46 constant, each heat collecting fin 46 is arranged between the inner peripheral surface of each flat surface portion 41 of the pipe 31 and the outer peripheral surface of the flat portion 51 of the shield 50 base portion opposed thereto. It is easy to arrange the fin portions 48 as long as possible. In other words, the structure of each heat collection fin 46 and thus each thermoelectric unit 32 can be easily shared. Note that the cross-sectional shape of the shield 50 preferably corresponds to the cross-sectional shape of the pipe 31. This is because it is easy to set the inner peripheral surface of each flat surface portion 41 of the pipe 31 and the outer peripheral surface of the flat portion 51 of the shield 50 base opposite thereto in parallel along the exhaust direction.

  The exhaust upstream side of the shield 50 is a tapered cone portion 54 as it approaches the upstream tip. The cone part 54 of the shield 50 according to the embodiment has a quadrangular pyramid shape because the base part has a quadrangular cross section. If the shield 50 is simply disposed in the pipe 31, the flow resistance of the exhaust gas increases. However, since the cone part 54 is formed on the exhaust upstream side of the shield 50, the pipe 31 is formed by the cone part 54. The exhaust gas can be smoothly guided to the narrow passage 52 between the shield 50 and the increase in flow resistance of the exhaust gas by the shield 50 is suppressed. It is sufficient that the shape of the cone portion 54 corresponds to the cross-sectional shape of the shield 50. That is, the cone portion 54 is not limited to a quadrangular pyramid shape, and may be a polygonal pyramid shape. Note that the exhaust upstream side of the shield 50 is not limited to the cone portion 54, and may be provided with a stationary blade or a movable blade as long as the exhaust gas can be smoothly guided to the narrow passage 52, or a spiral A shaped screw body may be provided.

  As is clear from the above description, the embodiment includes a pipe 31 through which exhaust gas flows, and a plurality of thermoelectric units 32 having a plate-like thermoelectric module 33 that generates power by a temperature difference between the low temperature side and the high temperature side, In the thermoelectric generator 30 that heats the high temperature side of each thermoelectric module 33 with the exhaust gas, the pipe 31 is formed in a polygonal cross section, and the thermoelectric unit 32 group is attached to each flat surface portion 41 of the pipe 31. Therefore, the plurality of thermoelectric units 32 can be densely arranged on the outer peripheral surface of the pipe 31 having a polygonal cross section. For this reason, the heat collection efficiency from the said exhaust gas can be improved, and the power generation efficiency in the said thermoelectric power generation apparatus 30 whole can be improved by extension.

  Further, the heat collecting fins 46 provided on the high temperature side of the thermoelectric modules 33 are protruded into the pipes 31 and shields as heat medium guide members for sending the exhaust gas to the heat collecting fins 46 side. 50, the exhaust gas can be actively supplied to the heat collecting fins 46 due to the presence of the shield 50, and the heat (waste heat) of the exhaust gas can be efficiently supplied. It can be transmitted to the fin 46. The heat collection efficiency from the exhaust gas to the heat collection fins 46 is high, and the power generation efficiency can be improved.

  A heat shield fin 46 provided on the high temperature side of each thermoelectric module 33 protrudes into the pipe 31 and a shield 50 that narrows the cross-sectional area inside the pipe 31 is provided from the inner peripheral surface of the pipe 31. Since the heat collection fins 46 are positioned between the inner peripheral surface of the pipe 31 and the outer peripheral surface of the shield 50, the heat collecting fins 46 are positioned between the inner peripheral surface of the pipe 31 and the outer periphery of the shield 50. The exhaust gas is actively sent to and from the surface, and the cost can be reduced with a simple configuration, but the heat collection efficiency from the exhaust gas to each of the heat collection fins 46 can be further improved. Contributes to improved efficiency.

  In addition, since the inner peripheral surface of each of the flat portions 41 of the pipe 31 and the outer peripheral surface of the shield 50 facing the same are set in parallel, the heat collecting fins 46 of the thermoelectric units 32 are set in parallel. When the projecting length of each of the pipes 31 is made constant, the heat collecting fins 46 are extended as much as possible between the inner peripheral surface of each flat surface portion 41 of the pipe 31 and the outer peripheral surface of the shield 50 facing it. And densely arranged. That is, the structure of each heat collecting fin 46 and thus each thermoelectric unit 32 can be made common, which contributes to improving the versatility of each thermoelectric unit 32.

  In addition, since the upstream side of the shield 50 is formed into a tapered cone portion 54 as it approaches the upstream tip portion, the pipe 31 and the shield 50 are separated by the cone portion 54. The exhaust gas can be smoothly guided to the narrow passage 52 therebetween, and an increase in the flow resistance of the exhaust gas by the shield 50 can be suppressed.

  In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the thermoelectric generator 30 of the present application may be disposed in the exhaust path of the main engine 21.

DESCRIPTION OF SYMBOLS 1 Ship 2 Hull 4 Funnel 11 Engine room 21 Main engine 23 Electric power generation device 24 Diesel generator 25 Electric power generation engine 27 Exhaust path 30 Thermoelectric power generation device 31 Pipe 32 Thermoelectric unit 33 Thermoelectric module 41 Flat part 43 Opening hole 45 Cooling case 46 Heat collection Fin 48 Fin portion 49 Temperature control member 50 Shield 51 Flat portion 54 Cone portion

Claims (4)

A pipe through which a heat medium flows, and a plurality of thermoelectric units having a plate-like thermoelectric module that generates electric power according to a temperature difference between the low temperature side and the high temperature side, and a collection provided on the high temperature side of each thermoelectric module in the pipe In the thermoelectric generator that projects the heat fins and heats the heat collection fins with the heat medium,
Between the high temperature side of each thermoelectric module and the heat collecting fin, a non-liquid cooling type temperature control member that suppresses heat transfer to the high temperature side of each thermoelectric module is interposed,
The temperature control member is configured to adjust the reachable temperature on the high temperature side by laminating a metal plate, a ceramic plate, or a combination thereof having a known contact thermal resistance value and high reproducibility .
Thermoelectric generator. The temperature control member is configured by alternately laminating steel plates and alumina plates,
The thermoelectric generator according to claim 1. As a material used for each thermoelectric module, a material mainly composed of bismuth and tellurium is used.
The thermoelectric generator according to claim 1 or 2. The thermoelectric generator according to any one of claims 1 to 3 is disposed in an exhaust path of an internal combustion engine mounted in a ship body.
Ship.

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