heat exchanger

Abstract

To efficiently exchange heat between the first fluid and the second fluid. [Solution] The economizer 10, which is a heat exchanger, has a three-dimensional structure 20 skeleton in which unit structures 24 formed of heat transfer walls 23 are arranged regularly and continuously in the XYZ directions. The unit structures 24 include a first unit structure 241 in which both sides of the heat transfer wall 23 are set to flow path portions 31 for combustion gas G2, and a second unit structure 242 in which one side of the heat transfer wall 23 is set to flow path portion 32 for water W and the other side is set to flow path portion 32 for combustion gas G2. The second unit structure 242 is provided with a heat-conductive partition wall 25 at its end in at least one direction of the XYZ directions, and is arranged continuously in the direction in which the partition wall 25 is not provided, thereby forming a fluid channel 28 in which the flow path portions 32 of water W communicate with each other. The first unit structures 241 are arranged to surround the direction in which the partition wall 25 of the second unit structure 242 is provided.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a heat exchanger.

Background Art

[0002] In the technical field related to heat exchangers, a heat exchanger as disclosed in Patent Document 1 is known. In Patent Document 1, the heat exchanger includes a first flow path surrounded by a first flow path wall, a second flow path surrounded by a second flow path wall formed separately from the first flow path wall, and a third flow path wall formed by the space between the first flow path wall and the second flow path wall. A first fluid flows through the first flow path, a second fluid flows through the second flow path, and a third fluid flows through the third flow path. Heat exchange is performed between the first fluid and the third fluid, and heat exchange is performed between the second fluid and the third fluid.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When heat-exchanging a first fluid and a second fluid having mutually different heat transfer rates, a technology capable of efficiently performing heat exchange is desired.

[0005] The technology disclosed in this specification aims to efficiently heat-exchange a first fluid and a second fluid.

Means for Solving the Problems

[0006] This specification discloses a heat exchanger. The heat exchanger has a three-dimensional shape as a unit structure, which is formed by heat transfer walls whose outer shape is defined by at least one of a pair of parallel curved surfaces and planes, and the unit structure has a skeleton of a three-dimensional structure in which the unit structures are regularly and continuously repeated in the XYZ directions. The unit structure includes a first unit structure in which both sides of the heat transfer wall are set as flow paths for a first fluid, and a second unit structure in which one side of the heat transfer wall is set as a flow path for a second fluid and the other side is set as a flow path for a first fluid. The second unit structure is provided with thermally conductive partitions at its ends in two directions of the XYZ directions, and is arranged continuously in the direction in which there are no partitions, thereby forming a fluid channel in which adjacent flow paths for the second fluid communicate with each other. The first unit structure is arranged to surround the direction in which the partitions of the second unit structure are provided. [Effects of the Invention]

[0007] According to the technology disclosed herein, the first fluid and the second fluid are efficiently heat-exchanged. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing a boiler according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram showing the economizer according to the first embodiment. [Figure 3] Figure 3 is a schematic perspective view showing a part of the three-dimensional structure according to the first embodiment. [Figure 4] Figure 4 is a schematic cross-sectional view showing a unit structure according to the first embodiment. [Figure 5] Figure 5 is a schematic cross-sectional view showing a unit structure according to the second embodiment. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings. The components of the embodiments described below can be combined as appropriate. In addition, some components may be omitted.

[0010] [First Embodiment] The first embodiment will be described.

[0011] <Boiler> Figure 1 is a schematic diagram showing a boiler 1 according to the first embodiment. As shown in Figure 1, the boiler 1 comprises a boiler body 4, an air intake pipe 5, a blower 6, a fuel supply device 7, an exhaust pipe 8, a feedwater device 9, and an economizer 10.

[0012] The boiler body 4 generates steam by heating water W. The boiler body 4 has a boiler 2 to which water W is supplied, and a burner 3 that burns fuel to heat the water W in the boiler 2. The boiler 2 has water tubes 2A, a lower header 2B, and an upper header 2C. The water tubes 2A are cylindrical members through which water W flows. The water tubes 2A are long in the vertical direction. Multiple water tubes 2A are provided. The lower end of the water tubes 2A is connected to the lower header 2B. The upper end of the water tubes 2A is connected to the upper header 2C. The lower header 2B contains water W. The water W contained in the lower header 2B is supplied to each of the multiple water tubes 2A. The water tubes 2A allow water W from the lower header 2B to flow through them. The water tubes 2A are heated by the combustion gas G2 generated in the burner 3. When the water tubes 2A are heated, the water W flowing through the water tubes 2A is heated and steam is generated. The steam generated in water pipe 2A is supplied to the upper header 2C. The upper header 2C contains the steam supplied from water pipe 2A.

[0013] The air intake pipe 5 is connected to the blower 6 and the boiler 2, respectively. The blower 6 supplies combustion air A1 to the air intake pipe 5. The combustion air A1 supplied from the blower 6 flows through the air intake passage 5A inside the air intake pipe 5. The fuel supply device 7 supplies fuel gas G0 to the air intake passage 5A. The fuel supply device 7 includes a fuel supply pipe 7A having a supply port for supplying fuel gas G0 to the air intake passage 5A, and a flow control valve 7B that adjusts the flow rate of fuel gas G0 supplied from the fuel supply pipe 7A to the air intake passage 5A. In the air intake passage 5A, the combustion air A1 and fuel gas G0 are mixed to generate premixed gas G1. The premixed gas G1 is supplied to the burner 3.

[0014] Burner 3 burns premixed gas G1 to produce combustion gas G2. Burner 3 heats the water tube 2A with the combustion gas G2. When the water tube 2A is heated, the water W flowing through the water tube 2A is heated and steam is generated. The generated steam is collected by the upper header 2C and then discharged through a steam pipe (not shown).

[0015] The exhaust pipe 8 is connected to the boiler body 2. The combustion gas G2 discharged from the boiler body 2 flows through the flue 8A, which is the exhaust passage inside the exhaust pipe 8. After flowing through the flue 8A, the combustion gas G2 is discharged to the outside of the boiler 1.

[0016] The water supply device 9 supplies water W to the boiler 2 via the economizer 10. The water supply device 9 includes a water supply line 9B connecting the water source 9A and the economizer 10, a water supply pump 9C that is driven to supply water W to the economizer 10, and a flow control valve 9D that adjusts the flow rate of water W supplied to the economizer 10.

[0017] The economizer 10 is located in the flue 8A through which the combustion gas G2 flows. The economizer 10 exchanges heat between the combustion gas G2 discharged from the boiler 2 and the water W supplied from the feedwater device 9. The water W heated by the combustion gas G2 in the economizer 10 is supplied to the lower header 2B of the boiler 2 via the feedwater line 9E. The lower header 2B contains the water W supplied from the feedwater device 9 via the economizer 10.

[0018] <Economizer> FIG. 2 is a diagram schematically showing an economizer 10 according to the first embodiment. In the following description, a three-dimensional orthogonal coordinate system is set for the economizer 10, and the positional relationship of each part will be described while referring to this three-dimensional orthogonal coordinate system. A direction parallel to the X-axis in the horizontal plane is defined as the X-axis direction. A direction parallel to the Y-axis orthogonal to the X-axis in the horizontal plane is defined as the Y-axis direction. A direction parallel to the Z-axis orthogonal to each of the X-axis and the Y-axis is defined as the Z-axis direction. The X-axis direction is the front-rear direction. The Y-axis direction is the left-right direction. The Z-axis direction is the up-down direction. The +X direction is the front. The -X direction is the rear. The +Y direction is the left. The -Y direction is the right. The +Z direction is the up. The -Z direction is the down.

[0019] The economizer 10 is a heat exchanger that exchanges heat between combustion gas G2 and water W. The economizer 10 exchanges heat between the combustion gas G2, which is the first fluid, and the water W, which is the second fluid. The heat transfer rate of the combustion gas G2 (gas) is different from that of the water W (liquid). The heat transfer rate of the combustion gas G2 is lower than that of the water W. The temperature of the combustion gas G2 before flowing into the economizer 10 is higher than the temperature of the water W before flowing into the economizer 10. When the combustion gas G2 and the water W exchange heat, the temperature of the combustion gas G2 decreases and the temperature of the water W increases.

[0020] As shown in FIG. 2, the economizer 10 includes a three-dimensional structure 20 through which the combustion gas G2 and the water W respectively flow, a right header 11, and a left header 12. The three-dimensional structure 20 is arranged in a flue 8A through which the combustion gas G2 flows. FIG. 2 shows a schematic external appearance of the three-dimensional structure 20.

[0021] The three-dimensional structure has a first flow path 21 and a second flow path 分开by a heat transfer wall 23. The first flow path and the second flow path are alternately arranged in each of the X-axis direction, the Y-axis direction, and the Z-axis direction. The heat transfer wall 23 is formed along a triply periodic surface (triply periodic minimal surface). The first flow path and the second flow path are separated by the heat transfer wall 23 along the triply periodic surface.

[0022] The right header 11 is located on the right side of the three-dimensional structure 20. The left header 12 is located on the left side of the three-dimensional structure 20. The lower part of the three-dimensional structure 20 is provided with an inlet 21A for the first flow path 21 and an inlet 22A for the second flow path 22, which correspond to the inlet of the combustion gas G2. The upper part of the three-dimensional structure 20 is provided with an outlet 21B for the first flow path 21 and an outlet 22B for the second flow path 22, which correspond to the outlet of the combustion gas G2. The right side of the three-dimensional structure 20 is provided with an inlet 22A for the second flow path 22 of the second unit structure 242, which will be described later. The left side of the three-dimensional structure 20 is provided with an outlet 22B for the second flow path 22 of the second unit structure 242. In the right and left parts of the three-dimensional structure 20, the openings of the first channel 21 and the second channel 22 of the first unit structure 241, as well as the opening of the first channel 21 of the second unit structure 242, are sealed.

[0023] The combustion gas G2 discharged from the boiler body 2 flows into the inlet 21A of the first flow path 21 and the inlet 22A of the second flow path 22. The combustion gas G2 discharged from the three-dimensional structure 20 is discharged from the outlet 21B of the first flow path 21 and the outlet 22B of the second flow path 22. A water supply line 9B is connected to the right header 11. A water supply line 9E is connected to the left header 12.

[0024] <3D structure> Figure 3 is a schematic perspective view showing a part of the three-dimensional structure 20 according to the first embodiment. Figure 3 shows the appearance of a unit structure 24, which is a part of the three-dimensional structure 20. The unit structure 24 has a cubic shape in the space occupied by the first channel 21, the second channel, and the heat transfer wall 23. The skeleton of the three-dimensional structure 20 is formed by arranging a plurality of unit structures 24 as shown in Figure 3. The unit structures 24 are arranged regularly and continuously in the XYZ directions. The three-dimensional structure 20 includes a plurality of unit structures 24 arranged regularly and continuously in the XYZ directions.

[0025] The unit structure 24 has a three-dimensional shape formed by the heat transfer wall 23. The heat transfer wall 23's external shape is defined by at least one of a pair of parallel curved surfaces and a plane. In this embodiment, the external shape of the heat transfer wall 23 is defined by a pair of mutually parallel curved surfaces. Alternatively, the external shape of the heat transfer wall 23 may be defined by a pair of mutually parallel planes. The external shape of the heat transfer wall 23 may be defined by a pair of mutually parallel curved surfaces and a pair of mutually parallel planes. The first flow path 21 and the second flow path 22 are separated by the heat transfer wall 23.

[0026] The three-dimensional structure 20 is constructed by applying a required thickness to a triple-periodic surface, based on the triple-periodic surface. The thickness of the heat transfer wall 23 is, for example, 0.4 mm. The heat transfer wall 23 is formed to follow the triple-periodic surface. A triple-periodic surface (triple-periodic minimum surface) is a surface with a minimum area among surfaces bounded by a closed curve given in three-dimensional space. Examples of triple-periodic surfaces include Schoen's gyroid surface (G surface), Schwarz's D surface, or Schoen's I-WP surface. In this embodiment, the three-dimensional structure 20 has a gyroid structure. The heat transfer wall 23 is formed to follow the gyroid surface.

[0027] A gyroid surface is a minimal surface that can be infinitely connected in three different directions and divides space into two regions. In an embodiment, gyroid surfaces can be infinitely connected in the X-axis, Y-axis, and Z-axis directions, respectively.

[0028] A gyroid surface is a surface whose area is minimized under given boundary conditions, and whose curvature becomes zero upon integration. A gyroid surface can be represented by the following approximation using trigonometric functions, shown in equation (1).

[0029] sinx·cosy+siny·cosz+sinz·cosx=0 …(1)

[0030] The heat transfer wall 23 is a wall centered on a hypothetical curved surface represented by equation (1), with a substantially uniform thickness in the direction normal to that curved surface.

[0031] <Unit Structure> Figure 4 is a schematic cross-sectional view showing a unit structure 24 according to the first embodiment. As shown in Figure 4, the unit structure 24 includes a first unit structure 241 and a second unit structure 242. Each of the first unit structure 241 and the second unit structure 242 includes a heat transfer wall 23. The second unit structure 242 is provided with a heat-conductive partition wall 25. The first unit structure 241 and the second unit structure 242 are separated by the partition wall 25. The partition wall 25 is provided at the boundary between the first unit structure 241 and the second unit structure 242.

[0032] The unit structure 24 has a first channel 21 and a second channel 22 separated by a heat transfer wall 23. The first channel 21 and the second channel 22 are arranged alternately in the X-axis, Y-axis, and Z-axis directions, respectively. If there is no partition wall 25, the volume of the first channel 21 and the volume of the second channel 22 in the unit structure 24 are equal.

[0033] The partition wall 25 is provided in the second flow path 22. The second flow path 22 is defined by the heat transfer wall 23. The partition wall 25 is provided so as to divide the second flow path 22 into two flow path portions. The partition wall 25 divides the second flow path 22 into a flow path portion 31 through which combustion gas G2 flows and a flow path portion 32 through which water W flows. The first flow path 21 is the flow path portion 31 through which combustion gas G2 flows. In the multiple repeatedly arranged unit structures 24, the proportion of the volume occupied by the flow path portion 31 for combustion gas G2 is greater than the proportion of the volume occupied by the flow path portion 32 for water W. In Figure 4, the flow path portion 31 for combustion gas G2 is a hatched portion with dot hatching, and the flow path portion 32 for water W is a white portion without hatching.

[0034] The first unit structure 241 includes the first flow path 21 and a part of the second flow path 22. The second unit structure 242 includes the first flow path 21 and a part of the second flow path 22. The first unit structure 241 includes the flow path portion 31 for the combustion gas G2 but does not include the flow path portion 32 for the water W. The second unit structure 242 includes the flow path portion 31 for the combustion gas G2 and the flow path portion 32 for the water W.

[0035] As shown in Figure 4, both sides of the heat transfer wall 23 of the first unit structure 241 are set as flow path portions 31 for the combustion gas G2. One side of the heat transfer wall 23 of the second unit structure 242 is set as a flow path portion 32 for water W, and the other side of the heat transfer wall 23 of the second unit structure 242 is set as a flow path portion 31 for the combustion gas G2.

[0036] The second unit structure 242 is provided with a thermally conductive partition wall 25 at at least one end of the second unit structure 242 in one of the XYZ directions, which separates it from the water W flow path portion 32. In the example shown in Figure 4, the partition wall 25 is provided at the end of the second unit structure 242 in the Z-axis direction. The partition wall 25 may also be provided at the ends of the second unit structure 242 in two of the XYZ directions. The partition wall 25 may also be provided at the end of the second unit structure 242 in the Z-axis direction and the end in the X-axis direction.

[0037] The second unit structures 242 are arranged continuously in the Y-axis and X-axis directions where no partition walls 25 are provided, thereby forming a fluid channel 28 through which adjacent water flow channels 32 communicate with each other. Of the second unit structures 242 arranged continuously in the X-axis direction, the +X-direction end (front end) and the -X-direction end (rear end) are provided with closing walls (not shown) that seal the water flow channels 32. In this embodiment, the water W flows through the fluid channel 28 from right (-Y direction) to left (+Y direction).

[0038] The first unit structure 241 is arranged to surround the direction to which the partition wall 25 of the second unit structure 242 is attached. In the example shown in Figure 4, the partition wall 25 is attached to the Z-axis end of the second unit structure 242. The first unit structure 241 is positioned in the Z-axis direction of the second unit structure 242. In the example shown in Figure 4, the first unit structure 241 is arranged in the +Z direction (upwards) and -Z direction (downwards) of the second unit structure 242. When the partition wall 25 is attached to the Z-axis end and the X-axis end of the second unit structure 242, the first unit structure 241 is arranged in the +Z direction (upwards), -Z direction (downwards), +X direction (forwards), and -X direction (backwards) of the second unit structure 242.

[0039] The coolant, water W, flows through the fluid channel 28. The fluid channel 28 is defined between the heat transfer wall 23 and the partition wall 25. In the second unit structure 242, the combustion gas G2 comes into contact with the wall surface of the heat transfer wall 23 that is not in contact with the fluid channel 28. In the second unit structure 242, the combustion gas G2 flowing through the first flow path 21 and the water W flowing through the fluid channel 28 exchange heat via the heat transfer wall 23 of the second unit structure 242. The combustion gas G2 flowing through the flow path portion 31 of the first unit structure 241 and the water W flowing through the fluid channel 28 of the second unit structure 242 exchange heat via the partition wall 25.

[0040] <Manufacturing of three-dimensional structures> In the embodiment, a three-dimensional structure 20 is formed by regularly and continuously arranging unit structures 24, as described with reference to Figure 4, in the XYZ directions. The three-dimensional structure 20 is integrally formed by three-dimensional additive manufacturing. The three-dimensional structure 20 is integrally formed by a 3D printer.

[0041] When a three-dimensional additive manufacturing of a three-dimensional structure 20, at least two first unit structures 241 may be arranged between two second unit structures 242 located at the shortest distance in at least one direction perpendicular to the direction of travel of the fluid channel 28. In this embodiment, the direction of travel of the fluid channel 28 is the Y-axis direction. At least two first unit structures 241 may be arranged between two second unit structures 242 located at the shortest distance in the Z-axis direction. Alternatively, one first unit structure 241 may be arranged between two second unit structures 242 located at the shortest distance in the Z-axis direction.

[0042] <Flow of combustion gases and water> As shown in Figure 2, a portion of the combustion gas G2 discharged from the boiler 2 flows into the first flow paths 21 (flow path portions 31) of the first unit structure 241 and the second unit structure 242, respectively, from inlets 21A and 22A. The combustion gas G2 that has flowed through the first flow paths 21 (flow path portions 31) of the first unit structure 241 and the second unit structure 242 is discharged to the outside of the boiler 1 from outlets 21B and 22B. In addition, a portion of the combustion gas G2 discharged from the boiler 2 flows into a flow path portion 31, which is part of the second flow path 22 of the first unit structure 241, from inlet 22A. The combustion gas G2 that has flowed through the flow path portion 31, which is part of the second flow path 22 of the first unit structure 241, is discharged to the outside of the boiler 1 from outlet 22B.

[0043] Water W from the water supply line 9B flows into the flow channel portion 32, which is part of the second flow channel 22 of the second unit structure 242, via the right header 11. The water W that has flowed through the flow channel portion 32, which is part of the second flow channel 22 of the second unit structure 242, is supplied to the lower header 2B of the boiler body 2 via the left header 12 and the water supply line 9E.

[0044] <Effects> As described above, in the embodiment, the economizer 10, which is a type of heat exchanger, has a three-dimensional shape formed by a heat transfer wall 23 whose outer shape is defined by at least one of a pair of parallel curved surfaces and a plane, and this unit structure 24 has a skeleton of a three-dimensional structure 20 in which the unit structure 24 is regularly and continuously repeated in the XYZ direction. The unit structure 24 includes a first unit structure 241 in which both sides of the heat transfer wall 23 are set as flow path portions 31 for the combustion gas G2, which is the first fluid, and a second unit structure 242 in which one side of the heat transfer wall 23 is set as a flow path portion 32 for the water W, which is the second fluid, and the other side is set as a flow path portion 31 for the combustion gas G2. The second unit structure 242 is provided with a thermally conductive partition wall 25 at at least one end in the XYZ direction that separates it from the flow path portion 32 for the water W. The second unit structure 242 is arranged continuously in the direction where no partition wall 25 is provided, thereby forming a fluid channel 28 in which adjacent water W flow path portions 32 communicate with each other. The first unit structure 241 is arranged so as to surround the direction in which the partition wall 25 of the second unit structure 242 is provided.

[0045] According to the embodiment, a first flow path 21 and a second flow path 22 are provided by a heat transfer wall 23, and the second flow path 22 is divided by a partition wall 25 into a flow path portion 31 for combustion gas G2 and a flow path portion 32 for water W. The first flow path 21 is the flow path portion 31 for combustion gas G2. In the three-dimensional structure 20, the heat transfer area of ​​the flow path portion 31 for combustion gas G2 is larger than the heat transfer area of ​​the flow path portion 32 for water W. As a result, the economizer 10 can efficiently exchange heat between the combustion gas G2, which has a low heat transfer coefficient, and the water W, which has a high heat transfer coefficient. That is, the heat transfer wall 23, which is in contact with the combustion gas G2 on both sides, can exhibit the same function as a heat transfer fin.

[0046] For example, if the heat transfer area of ​​the flow path portion 31 of the combustion gas G2 is equal to the heat transfer area of ​​the flow path portion 32 of the water W, it may become difficult to efficiently exchange heat between the combustion gas G2, which has a low heat transfer coefficient, and the water W, which has a high heat transfer coefficient.

[0047] According to the embodiment, when a first flow path 21 and a second flow path 22 with equal volumes are formed by the heat transfer wall 23, the second flow path 22 is divided by the partition wall 25 into a flow path portion 31 for combustion gas G2 and a flow path portion 32 for water W. That is, a portion of the second flow path 22 is used as the flow path portion 31 for combustion gas G2, and a portion of the second flow path 22 is used as the flow path portion 32 for water W. The first flow path 21 is the flow path portion 31 for combustion gas G2. Therefore, the heat transfer area of ​​the flow path portion 31 for combustion gas G2 is larger than the heat transfer area of ​​the flow path portion 32 for water W. As a result, the economizer 10 can efficiently exchange heat between the combustion gas G2, which has a low heat transfer coefficient, and water W, which has a high heat transfer coefficient.

[0048] Furthermore, if the volume of the flow path portion 31 for combustion gas G2 is small, excessive pressure loss may occur when the combustion gas G2 passes through. According to this embodiment, the volume of the flow path portion 31 for combustion gas G2 is large, so the pressure loss of the combustion gas G2 is suppressed.

[0049] [Second Embodiment] A second embodiment will now be described. In the following description, components that are the same as or equivalent to those in the first embodiment described above will be denoted by the same reference numerals, and the descriptions of those components will be simplified or omitted.

[0050] <Unit Structure> Figure 5 is a schematic cross-sectional view showing a unit structure 24 according to the second embodiment. As shown in Figure 5, the unit structure 24 includes a first unit structure 241 and a second unit structure 242. Each of the first unit structure 241 and the second unit structure 242 includes a heat transfer wall 23. The second unit structure 242 is provided with a heat-conductive partition wall 25. The first unit structure 241 and the second unit structure 242 are separated by the partition wall 25. The partition wall 25 is provided at the boundary between the first unit structure 241 and the second unit structure 242.

[0051] The partition wall 25 is provided in the second flow path 22. The second flow path 22 is defined by the heat transfer wall 23. The partition wall 25 is provided so as to divide the second flow path 22 into two flow path portions. The partition wall 25 divides the second flow path 22 into a flow path portion 31 through which combustion gas G2 flows and a flow path portion 32 through which water W flows. The first flow path 21 is the flow path portion 31 through which combustion gas G2 flows. In the repeatedly arranged unit structures 24, the proportion of the volume occupied by the flow path portion 31 for combustion gas G2 is greater than the proportion of the volume occupied by the flow path portion 32 for water W. In Figure 5, the flow path portion 31 for combustion gas G2 is a hatched portion with dot hatching, and the flow path portion 32 for water W is a white portion without hatching.

[0052] As shown in Figure 5, both sides of the heat transfer wall 23 of the first unit structure 241 are set as flow path portions 31 for the combustion gas G2. One side of the heat transfer wall 23 of the second unit structure 242 is set as a flow path portion 32 for water W, and the other side of the heat transfer wall 23 of the second unit structure 242 is set as a flow path portion 31 for the combustion gas G2.

[0053] The second unit structure 242 is provided with thermally conductive partitions 25 at two of its ends in the XYZ directions, separating it from the water W flow channel 32. In the example shown in Figure 5, the partitions 25 are provided at the Z-axis end and the X-axis end of the second unit structure 242.

[0054] The second unit structures 242 are arranged continuously in the Y-axis direction where no partition walls 25 are provided, thereby forming fluid channels 28 through which adjacent water flow channels 32 communicate with each other. In this embodiment, the water W flows through the fluid channels 28 from right (-Y direction) to left (+Y direction).

[0055] The first unit structure 241 is arranged to surround the direction in which the partition wall 25 of the second unit structure 242 is attached. In the example shown in Figure 5, the partition wall 25 is attached to the Z-axis end and the X-axis end of the second unit structure 242. The first unit structure 241 is arranged in the +Z direction (upwards), -Z direction (downwards), +X direction (forwards), and -X direction (backwards) of the second unit structure 242.

[0056] In one embodiment, the first unit structure 241 and the second unit structure 242 are arranged such that a plurality of fluid channels 28 extending in the same direction are formed. In the example shown in Figure 5, the second unit structure 242 has two fluid channels 28 arranged in the X-axis direction. Each of the two fluid channels 28 extends in the Y-axis direction. In the Z-axis direction, the positions of one fluid channel 28 and the other fluid channel 28 may be the same as shown in the figure, or they may be different with a pitch difference.

[0057] <Effects> As explained above, in this embodiment as well, in the three-dimensional structure 20, the proportion of the volume occupied by the flow path portion 31 for combustion gas G2 is greater than the proportion occupied by the flow path portion 32 for water W. Since the proportion of the volume occupied by the flow path portion 31 for combustion gas G2 is greater than the proportion occupied by the flow path portion 32 for water W, the economizer 10 can efficiently exchange heat between the combustion gas G2, which has a low heat transfer coefficient, and the water W, which has a high heat transfer coefficient.

[0058] [Other embodiments] In the above-described embodiment, the heat exchanger is assumed to be the economizer 10. The heat exchanger may also be the heat exchanger of a heat device such as a latent heat recovery type gas water heater. [Explanation of symbols]

[0059] 1... Boiler, 2... Boiler body, 2A... Water pipe, 2B... Lower header, 2C... Upper header, 3... Burner, 4... Boiler body, 5... Air intake pipe, 5A... Air intake passage, 6... Blower, 7... Fuel supply device, 7A... Fuel supply pipe, 7B... Flow control valve, 8... Exhaust pipe, 8A... Flue, 9... Feedwater device, 9A... Feedwater source, 9B... Feedwater line, 9C... Feedwater pump, 9D... Flow control valve, 9E... Feedwater line, 10... Economizer (heat exchanger), 11... Right Header section, 12...Left header section, 20...Three-dimensional structure, 21...First flow path, 21A...Inlet, 21B...Outlet, 22...Second flow path, 22A...Inlet, 22B...Outlet, 23...Heat transfer wall, 24...Unit structure, 25...Partition wall, 28...Fluid channel, 31...Flow path section, 32...Flow path section, 241...First unit structure, 242...Second unit structure, A1...Combustion air, G0...Fuel gas, G1...Premixed gas, G2...Combustion gas.

Claims

1. A three-dimensional shape formed by a heat transfer wall whose outer shape is defined by at least one of a pair of parallel curved surfaces and planes is used as a unit structure, and the unit structure has a skeleton of a three-dimensional structure in which the units are arranged regularly and continuously in the XYZ directions. The aforementioned unit structure is A first unit structure in which both sides of the heat transfer wall are set as the flow path portion of the first fluid, The heat transfer wall includes a second unit structure in which one side is set as the flow path portion for the second fluid and the other side is set as the flow path portion for the first fluid, The second unit structure is, At least one end in the XYZ direction, a thermally conductive partition is provided for the flow path portion of the second fluid. By being continuously arranged in the direction in which the partition wall is not provided, a fluid channel is formed in which adjacent flow path portions of the second fluid communicate with each other. The first unit structure is, The partition wall of the second unit structure is arranged to surround the direction in which it is provided. heat exchanger.

2. The first unit structure and the second unit structure are arranged such that a plurality of fluid channels extending in the same direction are formed. The heat exchanger according to claim 1.

3. The first unit structure is arranged in pairs between two second unit structures located at the shortest distance from each other in at least one direction perpendicular to the direction of travel of the fluid channel. The heat exchanger according to claim 2.

4. Coolant is circulated through the fluid channel, and combustion gas is brought into contact with the wall surface of the heat transfer wall that is not in contact with the fluid channel. The heat exchanger according to claim 1.

5. The aforementioned three-dimensional structure is placed in the flue through which the combustion gas flows. The heat exchanger according to claim 4.

6. The aforementioned three-dimensional structure is formed by using a triple-periodic curved surface as a reference and applying the required thickness to this curved surface to constitute the heat transfer wall. The heat exchanger according to claim 1.

7. The aforementioned three-dimensional structure has a gyroid structure. The heat exchanger according to claim 6.

8. The aforementioned three-dimensional structure is integrally formed by three-dimensional additive manufacturing. The heat exchanger according to claim 1.

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