Energy converter

Abstract

The present invention controls a degradation in a thermoacoustic effect caused by unevenness in the temperature difference between a first heat exchanger and a second heat exchanger. This energy converter is built into a thermoacoustic device having a working gas sealed therein and performs energy conversion between thermal energy and acoustic energy. The energy converter comprises a heat accumulator, a first heat exchanger that is arranged facing one surface of one heat accumulator, and a second heat exchanger that is arranged facing another surface of the heat accumulator. The first heat exchanger is formed with a first high-temperature portion and a first low-temperature portion that have different temperatures, and the second heat exchanger is formed with a second high-temperature portion and a second low-temperature portion that have different temperatures. The first high-temperature portion in the first heat exchanger and the second high-temperature portion in the second heat exchanger face each other, and the first low-temperature portion in the first heat exchanger and the second low-temperature portion in the second heat exchanger face each other.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a thermoacoustic energy converter and a method of using the energy converter.

Background Art

[0002] A thermoacoustic engine (thermoacoustic device) includes a pipe enclosing a working gas that propagates sound waves, and a prime mover (energy converter) incorporated in the pipe. The energy converter includes a regenerator having a plurality of through-passages, and a heater and a cooler (heat exchanger) respectively disposed at both ends of the regenerator. Such an energy converter can be used, for example, as a thermoacoustic engine that converts thermal energy into acoustic energy (sound waves) in the regenerator by self-excitation of the working gas due to a temperature gradient generated between both ends of the regenerator.

[0003] Conventionally, in an energy converter, in order to improve the performance of a thermoacoustic device, it has been considered desirable that heat spreads uniformly in a cross section perpendicular to the through-passages of the regenerator. Therefore, a technique is known in which a plurality of heat source supply pipes through which a heated fluid flows are arranged on the outer periphery of the heater to reduce temperature unevenness in the cross section of the heater (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In energy converters like the one described above, it may not be possible to sufficiently reduce temperature variations in the cross-section of the heater. Furthermore, even if the temperature variations in the cross-section of the heater can be sufficiently reduced, if the temperature variations in the cross-section of the cooler cannot be reduced, temperature differences will occur between the heat exchangers located on both sides of the heat regenerator, reducing the thermoacoustic effect and potentially degrading the performance of the thermoacoustic device. [Means for solving the problem]

[0006] (1) An energy converter disclosed herein is incorporated into a thermoacoustic device in which a working gas is sealed, and performs energy conversion between thermal energy and acoustic energy, comprising: a heat accumulator having one surface and another surface, and having a plurality of through passages penetrating from one surface to the other surface; a first heat exchanger disposed opposite to the one surface of the heat accumulator; and a second heat exchanger disposed opposite to the other surface of the heat accumulator, wherein the first heat exchanger is configured to form a first high-temperature portion and a first low-temperature portion with different temperatures, and the second heat exchanger is configured to form a second high-temperature portion and a second low-temperature portion with different temperatures, the first high-temperature portion in the first heat exchanger and the second high-temperature portion in the second heat exchanger are opposite to each other, and the first low-temperature portion in the first heat exchanger and the second low-temperature portion in the second heat exchanger are opposite to each other.

[0007] In this energy converter, the temperature difference between the first and second heat exchangers is less uneven compared to configurations where, for example, the high-temperature portion of the first heat exchanger and the low-temperature portion of the second heat exchanger face each other, or configurations where there is no temperature difference between the first and second heat exchangers. Therefore, this energy converter can suppress the reduction in thermoacoustic effects caused by the temperature difference between the first and second heat exchangers.

[0008] (2) In the above-described energy converter, the first heat exchanger may be configured to have a first heat transfer tube through which a first fluid flows, thereby forming a first high-temperature portion and a first low-temperature portion, and the second heat exchanger may be configured to have a second heat transfer tube through which a second fluid, which is at a lower temperature than the first fluid, flows, thereby forming a second high-temperature portion and a second low-temperature portion. According to this energy converter, in a configuration in which each heat exchanger has a heat transfer tube, it is possible to suppress the reduction of thermoacoustic effects caused by uneven temperature differences between the first heat exchanger and the second heat exchanger.

[0009] (3) In the above-described energy converter, the first heat exchanger may have a plurality of first heat transfer tubes, and the second heat exchanger may have a plurality of second heat transfer tubes, wherein the first high-temperature portion of each first heat transfer tube and the second high-temperature portion of each second heat transfer tube face each other, and the first low-temperature portion of each first heat transfer tube and the second low-temperature portion of each second heat transfer tube face each other. With this energy converter, for example, compared to a configuration in which the first heat exchanger and the second heat exchanger each have only one heat transfer tube, the shorter length of each heat transfer tube results in a smaller temperature difference between the ends of the heat transfer tubes, which suppresses the temperature difference between each heat exchanger and suppresses the decrease in thermoacoustic effect caused by temperature unevenness between the first heat exchanger and the second heat exchanger.

[0010] (4) In the above-described energy converter, in the first heat exchanger, at least two adjacent first heat transfer tubes may be configured such that one of their first high-temperature portion and first low-temperature portion is closer to each other than the other portion, and in the second heat exchanger, at least two adjacent second heat transfer tubes may be configured such that one of their second high-temperature portion and second low-temperature portion is closer to each other than the other portion. With this energy converter, for example, compared to a configuration in each heat exchanger where the high-temperature portion of one heat transfer tube and the low-temperature portion of the other heat transfer tube are arranged to be close to each other, it is possible to suppress the influence on the temperature of each heat transfer tube due to heat transfer between adjacent heat transfer tubes.

[0011] (5) In the above-described energy converter, the first heat transfer tube and the second heat transfer tube may have the same shape, one end of the first heat transfer tube may be the inlet for the first fluid, and the end of the second heat transfer tube that is opposite to the one end of the first heat transfer tube may be the outlet for the second fluid. According to this energy converter, in a configuration in which the first heat transfer tube and the second heat transfer tube have the same shape, the reduction in thermoacoustic effect caused by uneven temperature differences between the first heat exchanger and the second heat exchanger can be suppressed by a simple configuration of reversing the direction of fluid flow.

[0012] (6) A method of using an energy converter disclosed herein is incorporated into a thermoacoustic device that is sealed with a working gas and performs energy conversion between thermal energy and acoustic energy, comprising: a heat accumulator having one surface and another surface and having a plurality of through passages penetrating from one surface to the other surface; a first heat exchanger disposed opposite to the one surface of the heat accumulator; and a second heat exchanger disposed opposite to the other surface of the heat accumulator and being at a lower temperature than the first heat exchanger, the method of using an energy converter that performs energy conversion between thermal energy and acoustic energy, comprising: a first heat exchange step of using the first heat exchanger to form a first high-temperature portion and a first low-temperature portion being at a lower temperature than the first high-temperature portion on the one surface of the heat accumulator; and a second heat exchange step of using the second heat exchanger to form a second high-temperature portion opposite to the first high-temperature portion and a second low-temperature portion opposite to the first low-temperature portion and being at a lower temperature than the second high-temperature portion on the other surface of the heat accumulator. According to the method of using this energy converter, it is possible to suppress the decrease in thermoacoustic effect caused by uneven temperature differences between the first heat exchanger and the second heat exchanger. [Effects of the Invention]

[0013] According to the energy converter and method of using the energy converter disclosed herein, it is possible to suppress the reduction of thermoacoustic effects caused by uneven temperature differences between the first heat exchanger and the second heat exchanger. [Brief explanation of the drawing]

[0014] [Figure 1] Perspective view showing a partially cutaway thermoacoustic device of the first embodiment. [Figure 2] Sectional view along line II-II in Figure 1 [Figure 3] An explanatory diagram showing the configuration of the heat transfer tubes in the first heat exchanger 60 and the second heat exchanger 70, and the temperature difference between them. [Figure 4] An explanatory diagram showing the configuration of the heat transfer tubes of the first heat exchanger 60a and the second heat exchanger 70a in the second embodiment, and the temperature difference between them. [Figure 5]Explanatory drawing showing the configuration of the heat transfer tubes of the first heat exchanger 60b and the second heat exchanger 70b and the temperature difference between the two in the third embodiment [Figure 6] Explanatory drawing showing the configuration of the heat transfer tubes of the first heat exchanger 60c and the second heat exchanger 70c and the temperature difference between the two in the fourth embodiment

Embodiments for Carrying Out the Invention

[0015] Specific examples of the technology disclosed by this specification will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is intended to be indicated by the claims and to include all modifications within the meaning and scope equivalent to the claims.

[0016] <First Embodiment> The embodiment will be described with reference to FIGS. 1 to 3. The thermoacoustic device 10 of the present embodiment is a cooling device for maintaining the temperature of an object at a temperature lower than room temperature by using acoustic energy.

[0017] (Overall Configuration of Thermoacoustic Device 10) As shown in FIG. 1, the thermoacoustic device 10 includes a pipe 20, a prime mover 30 and a cooler 40 disposed in the middle of the pipe 20. The prime mover 30 and the cooler 40 are examples of energy converters in the claims.

[0018] As shown in FIG. 1, the pipe 20 includes a plurality of main pipes 21, a plurality (two in this embodiment) of expansion pipes 22, and a plurality (two in this embodiment) of accommodation pipes 23. In this embodiment, the main pipe 21, the expansion pipe 22, and the accommodation pipe 23 are made of metal. The main pipe 21 is a pipe having a constant inner diameter. The expansion pipe 22 is a pipe in which the inner diameter of the central portion between both ends is larger than that of the main pipe 21.

[0019] As shown in FIGS. 1 and 2, the accommodation pipe 23 is a pipe whose inner diameter at the central portion between both ends is larger than that of the main pipe 21. More specifically, the accommodation pipe 23 is a pipe having openings 23A at both ends, and includes two first straight pipe portions 23B, two tapered portions 23C, and a second straight pipe portion 23D. The two first straight pipe portions 23B are two short straight pipe-like portions adjacent to each of the two openings 23A. The second straight pipe portion 23D is a short straight pipe-like portion located at the center between the two first straight pipe portions 23B and having an inner diameter larger than that of the first straight pipe portion 23B. The two tapered portions 23C connect between one first straight pipe portion 23B and the second straight pipe portion 23D and between the other first straight pipe portion 23B and the second straight pipe portion 23D, respectively, and are portions whose diameters are reduced from the second straight pipe portion 23D toward the first straight pipe portion 23B.

[0020] The plurality of main pipes 21 are respectively connected between the two accommodation pipes 23, between the accommodation pipe 23 and the expansion pipe 22, and between the two expansion pipes 22. A loop-shaped pipeline P1 is formed by the main pipe 21, the expansion pipe 22, and the accommodation pipe 23. An operating gas is enclosed inside the pipeline P1. The operating gas is not particularly limited as long as it can transmit sound waves, but an inert gas composed of helium, argon, or a mixed gas of helium and argon, or air is preferably used.

[0021] (Configuration of the prime mover 30) The prime mover 30 is a device for converting thermal energy into acoustic energy (sound waves), and is arranged inside one accommodation pipe 23 (the upper accommodation pipe 23 in FIG. 1). As shown in FIGS. 1 and 2, the prime mover 30 includes a regenerator 50, a first heat exchanger 60, and a second heat exchanger 70. The first heat exchanger 60, the regenerator 50, and the second heat exchanger 70 are arranged in this order side by side from one opening 23A of the accommodation pipe 23 toward the other opening 23A.

[0022] (Regenerator 50) The heat storage unit 50 is a thick, disc-shaped structure with one surface 52 (the right-hand surface in Figure 2) and the other surface 54 (the left-hand surface in Figure 2). The heat storage unit 50 is positioned perpendicular to the axial direction S (left-right direction in Figure 2) of the housing pipe 23, with one surface 52 facing one opening 23A of the housing pipe 23 and the other surface 54 facing the other opening 23A of the housing pipe 23. The heat storage unit 50 has numerous small through passages (not shown). These through passages penetrate from one surface 52 to the other surface 54 of the heat storage unit 50.

[0023] (First heat exchanger 60, second heat exchanger 70) The first heat exchanger 60 is positioned adjacent to one side 52 of the heat accumulator 50, as shown in Figures 2 and 3. The first heat exchanger 60 includes, for example, a first heat transfer tube 64 through which a high-temperature medium F1 passes, and fins (not shown) arranged around the first heat transfer tube 64. The high-temperature medium F1 is an example of the first fluid in the claims. As the high-temperature medium F1, for example, a heat transfer oil heated by waste heat from a factory can be used. The detailed configuration of the first heat exchanger 60 will be described later.

[0024] The second heat exchanger 70 is positioned adjacent to the other side 54 of the heat accumulator 50, as shown in Figures 2 and 3. The second heat exchanger 70 comprises, for example, a second heat transfer tube 74 through which a low-temperature medium F2 passes, and fins (not shown) arranged around the second heat transfer tube 74. The low-temperature medium F2 is an example of the second fluid in the claims. The heat transfer tubes 64 and 74 are made of, for example, metal (copper, copper alloy, aluminum alloy, etc.) or a material with high thermal conductivity.

[0025] (Configuration of the cooling unit 40) The cooler 40 is a heat pump that generates a temperature gradient when acoustic energy generated by the prime mover 30 is input, maintaining the temperature of the object at a temperature lower than room temperature. As shown in Figure 1, it is located inside the other housing piping 23. The cooler 40 comprises a heat accumulator 51 and a first heat exchanger 61 and a second heat exchanger 71, which are located on either side of the heat accumulator 51. The heat accumulator 51 and heat exchangers 61 and 71 in the cooler 40 have the same configuration as the heat accumulator 50 and heat exchangers 60 and 70 in the prime mover 30. In the cooler 40, a medium at a constant temperature (in this embodiment, water at room temperature) is supplied inside the first heat transfer tube 64 of the first heat exchanger 61, and the working gas near the first heat exchanger 61 becomes approximately room temperature. The second heat transfer tube 74 in the second heat exchanger 71 is connected to a heat exchanger provided in an external cooling system, and a refrigerant circulates inside this heat transfer tube. The above-mentioned constant-temperature medium is an example of the first fluid in the claims, and the above-mentioned refrigerant is an example of the second fluid in the claims.

[0026] (Detailed configuration of the first heat exchanger 60 and the second heat exchanger 70) Figure 3 is an explanatory diagram showing the configuration of the heat transfer tubes of the first heat exchanger 60 and the second heat exchanger 70, and the temperature difference between them. Figure 3(A) shows the piping configuration of the first heat transfer tube 64 of the first heat exchanger 60 in an axial S view of the housing piping 23. Figure 3(B) shows the piping configuration of the second heat transfer tube 74 of the second heat exchanger 70 in an axial S view of the housing piping 23. A dividing line X (dotted line) is shown in Figure 3. This dividing line X is a line that divides each heat exchanger 60, 70 into left and right halves in an axial S view of the housing piping 23. Hereinafter, the region to the left of dividing line X will be called the "left dividing region EL", and the region to the right of dividing line X will be called the "right dividing region ER". Note that fins are omitted in Figures 3(A) and (B).

[0027] As shown in Figure 3(A), the first heat exchanger 60 further includes an annular frame 62 that supports the first heat transfer tubes 64. The frame 62 is positioned such that the inner space of the frame 62 communicates with the opening 23A of the housing piping 23. Preferably, the frame 62 is made of a material with a lower thermal conductivity than the first heat transfer tubes 64. The first heat exchanger 60 has two first heat transfer tubes 64. One of the first heat transfer tubes 64 is the left heat transfer tube 64L, and is positioned in the left dividing region EL within the frame 62. The other first heat transfer tube 64 is the right heat transfer tube 64R, and is positioned in the right dividing region ER within the frame 62. Both of the first heat transfer tubes 64 are positioned on a predetermined plane perpendicular to the axial direction S of the housing piping 23.

[0028] The left-side heat transfer tube 64L is a single tube in its entirety. Furthermore, the left-side heat transfer tube 64L is positioned to extend along one side 52 of the condenser 50. That is, the distance between the left-side heat transfer tube 64L and one side 52 of the condenser 50 in the axial direction S of the housing piping 23 is uniform along the entire length of the left-side heat transfer tube 64L.

[0029] The left-side heat transfer tube 64L has four main sections 66 and three connecting sections 68. Each main section 66 extends linearly in a predetermined direction perpendicular to the axial direction S of the housing pipe 23 (the vertical direction in the plane of Figure 3). In a view of the housing pipe 23 in the axial direction S, the four main sections 66 are arranged at equal intervals in a direction perpendicular to the axial direction of the main section 66 (the horizontal direction in the plane of Figure 3). The total length of the main sections 66 decreases sequentially from the main section 66 located on the center side in the left-right direction of the frame 62 to the main section 66 located on the left side. The vertical ends of each main section 66 are supported by the frame 62.

[0030] In the left-side heat transfer tube 64L, the connecting section 68 is located within the frame 62 and connects the ends of adjacent main pipe sections 66. Specifically, the three connecting sections 68 include two upper connecting sections 68 and one lower connecting section 68. The upper connecting section 68 connects the upper ends of two adjacent main pipe sections 66. The lower connecting section 68 connects the lower ends of two adjacent main pipe sections 66. In the left-side heat transfer tube 64L, the upper connecting sections 68 and lower connecting sections 68 are arranged alternately in the left-right direction. In the example in Figure 3(A), the connecting section 68 closest to the dividing line X and the leftmost connecting section 68 are the upper connecting sections 68, and the connecting section 68 located between these two upper connecting sections 68 is the lower connecting section 68.

[0031] In the left heat transfer tube 64L, the lower end of the main tube section 66 closest to the dividing line X and the lower end of the leftmost main tube section 66 each penetrate the frame 62 and open downwards. The high-temperature medium F1 flows from the lower end of the main tube section 66 closest to the dividing line X to the lower end of the leftmost main tube section 66. As the high-temperature medium F1 flows through the left heat transfer tube 64L, its temperature decreases due to heat exchange with the working gas flowing through the housing piping 23. As a result, the temperature of the main tube section 66 closest to the dividing line X is highest, and the temperature of the leftmost main tube section 66 is lowest (see the white arrows shown in the left dividing region EL. "h" means high temperature, and "l" means low temperature). Consequently, in the portion of the first heat exchanger 60 located in the left dividing region EL, a first high-temperature section 65h is formed, which includes the main tube section 66 closest to the dividing line X, and a first low-temperature section 65l is formed, which includes the main tube section 66 located on the left side.

[0032] The right-side heat transfer tube 64R is a single tube in its entirety. Furthermore, the right-side heat transfer tube 64R is positioned to extend along one side 52 of the condenser 50. That is, the distance between the right-side heat transfer tube 64R and one side 52 of the condenser 50 in the axial direction S of the housing piping 23 is uniform along the entire length of the right-side heat transfer tube 64R.

[0033] The right-side heat transfer tube 64R has a shape that is point-symmetrical to the left-side heat transfer tube 64L. That is, the right-side heat transfer tube 64R has the shape of the left-side heat transfer tube 64L rotated 180 degrees around the central axis of the frame 62. Specifically, the right-side heat transfer tube 64R has four main tube sections 66 and three connecting sections 68. In the right-side heat transfer tube 64R, the total length of the main tube sections 66 decreases sequentially from the main tube section 66 located on the central side in the left-right direction of the frame 62 to the main tube section 66 located on the right side. The upper and lower ends of each main tube section 66 are supported by the frame 62.

[0034] In the right-side heat transfer tube 64R, the three connection sections 68 include one upper connection section 68 and two lower connection sections 68. In the example in Figure 3(A), the connection section 68 closest to the dividing line X and the rightmost connection section 68 are the lower connection sections 68, and the connection section 68 located between these two lower connection sections 68 is the upper connection section 68.

[0035] In the right-side heat transfer tube 64R, the upper end of the main tube section 66 closest to the dividing line X and the upper end of the main tube section 66 located on the far right each penetrate the frame 62 and open upward. The high-temperature medium F1 flows from the upper end of the main tube section 66 closest to the dividing line X to the upper end of the main tube section 66 located on the far right. As the high-temperature medium F1 flows through the right-side heat transfer tube 64R, its temperature decreases due to heat exchange with the working gas flowing through the housing piping 23. As a result, the temperature of the main tube section 66 closest to the dividing line X is highest, and the temperature of the main tube section 66 located on the far right is lowest (see the white arrow shown in the right-side dividing region ER). Consequently, in the portion of the first heat exchanger 60 located in the right-side dividing region ER, a first high-temperature section 65h including the main tube section 66 closest to the dividing line X and a first low-temperature section 65l including the main tube section 66 located on the far right are formed.

[0036] As shown in Figure 3(B), the second heat exchanger 70 further comprises an annular frame 72 that supports the second heat transfer tubes 74. The frame 72 has the same configuration as the frame 62 of the first heat exchanger 60, and is arranged so that the inner space of the frame 62 communicates with the opening 23A of the housing piping 23. The second heat exchanger 70 has two second heat transfer tubes 74. One of the second heat transfer tubes 74 is the left heat transfer tube 74L, and is located in the left dividing region EL within the frame 72. The other second heat transfer tube 74 is the right heat transfer tube 74R, and is located in the right dividing region ER within the frame 72. Both second heat transfer tubes 74 are located on a predetermined plane perpendicular to the axial direction S of the housing piping 23.

[0037] The left-side heat transfer tube 74L is, as a whole, a single tube. Furthermore, the left-side heat transfer tube 74L is positioned to extend along the other surface 54 of the condenser 50. That is, the distance between the left-side heat transfer tube 74L and the other surface 54 of the condenser 50 in the axial direction S of the housing piping 23 is uniform along the entire length of the left-side heat transfer tube 74L.

[0038] The left heat transfer tube 74L has the same shape as the left heat transfer tube 64L. However, the low-temperature medium F2 flows in the opposite direction to the high-temperature medium F1. That is, the low-temperature medium F2 flows from the lower end of the leftmost main tube section 66 to the lower end of the main tube section 66 closest to the dividing line X. As the low-temperature medium F2 flows through the left heat transfer tube 74L, its temperature rises due to heat exchange with the working gas flowing through the housing piping 23. Therefore, the temperature of the leftmost main tube section 66 is lowest, and the temperature of the main tube section 66 closest to the dividing line X is highest (see the white arrow shown in the left dividing region EL). As a result, in the second heat exchanger 70, the portion located in the left dividing region EL is formed into a second high-temperature section 75h including the main tube section 66 closest to the dividing line X, and a second low-temperature section 75l including the leftmost main tube section 66.

[0039] The right-side heat transfer tube 74R is, as a whole, a single tube. Furthermore, the right-side heat transfer tube 74R is positioned to extend along the other surface 54 of the condenser 50. That is, the distance between the right-side heat transfer tube 74R and the other surface 54 of the condenser 50 in the axial direction S of the housing piping 23 is uniform along the entire length of the right-side heat transfer tube 74R.

[0040] The right-side heat transfer tube 74R has a point-symmetric shape with respect to the left-side heat transfer tube 74L. The right-side heat transfer tube 74R has the same shape as the right-side heat transfer tube 64R. However, the low-temperature medium F2 flows in the opposite direction to the high-temperature medium F1. That is, the low-temperature medium F2 flows from the upper end of the main pipe section 66 located on the far right to the upper end of the main pipe section 66 closest to the dividing line X. As the low-temperature medium F2 flows through the right-side heat transfer tube 74R, its temperature rises due to heat exchange with the working gas flowing through the housing piping 23. Therefore, the temperature of the main pipe section 66 located on the far right is the lowest, and the temperature of the main pipe section 66 closest to the dividing line X is the highest (see the white arrow shown in the right-side dividing region ER). As a result, in the second heat exchanger 70, the portion located in the right-side dividing region ER is formed into a second high-temperature section 75h including the main pipe section 66 closest to the dividing line X, and a second low-temperature section 75l including the main pipe section 66 located on the far right.

[0041] (Operation of the thermoacoustic device 10) When the thermoacoustic device 10 is operated, a high-temperature medium F1 is flowed through the first heat exchanger 60, and heat exchange takes place between the working gas near one surface 52 and the high-temperature medium F1 in the heat accumulator 50. As a result, the temperature of the working gas near one surface 52 in the heat accumulator 50 is adjusted to approach the temperature of the high-temperature medium F1. In addition, a low-temperature medium F2 is flowed through the second heat exchanger 70, and heat exchange takes place between the working gas near the other surface 54 in the heat accumulator 50 and the low-temperature medium F2. As a result, the temperature of the working gas near the other surface 54 in the heat accumulator 50 is adjusted to approach the temperature of the low-temperature medium F2.

[0042] The action of these heat exchangers 60 and 70 creates a temperature gradient between one surface 52 and the other surface 54 of the heat accumulator 50. This causes the working gas inside the through-passage to become unstable and begin to vibrate. This vibration generates acoustic energy (sound waves). The generated acoustic energy travels through the inside of the pipe P1 and is input to the cooler 40.

[0043] When acoustic energy transmitted via the working gas is input to the heat accumulator 51 in the cooler 40, a temperature gradient is created between one surface 52 and the other surface 54. In the cooler 40, room temperature water flows through the first heat exchanger 61 located on the acoustic energy input side, and the water reaches a temperature of approximately room temperature. As a result, the temperature of the working gas near the second heat exchanger 70 in the heat accumulator 50 is adjusted to a temperature lower than room temperature due to the resulting temperature gradient. Heat exchange takes place between this lower-temperature working gas and the refrigerant, and the refrigerant, now at a lower temperature, is supplied to an external cooling system to cool the object.

[0044] Thus, in the thermoacoustic device 10, acoustic energy is generated in the prime mover 30 based on the temperature gradient between one surface 52 and the other surface 54 of the heat accumulator 50, and a temperature gradient is generated in the cooler 40 based on the input of acoustic energy between one surface 52 and the other surface 54 of the heat accumulator 51. Due to this thermoacoustic effect (for example, the conversion efficiency between thermal energy and acoustic energy), the thermoacoustic device 10 functions as a cooler. Herein, the inventors have newly discovered that even if temperature bias occurs in the cross section perpendicular to the axial direction S of the housing pipe 23 in the first heat exchangers 60, 61 and the second heat exchangers 70, 71, the decrease in the thermoacoustic effect in the prime mover 30 and the cooler 40 can be suppressed. In other words, if the temperature difference between the first heat exchangers 60, 61 and the second heat exchangers 70, 71 (temperature difference between the ends of the multiple through passages formed in the heat regenerators 50, 51) can be reduced, the decrease in the thermoacoustic effect in the prime mover 30 and the cooler 40 can be suppressed.

[0045] Here, the right side of Figure 3 shows the temperatures of the first heat exchanger 60 and the second heat exchanger 70. Graph G1 shows the temperature of the first heat exchanger 60 in a cross-section perpendicular to the axial direction S of the housing piping 23, and graph G2 shows the temperature of the second heat exchanger 70 in a cross-section perpendicular to the axial direction S of the housing piping 23. In this embodiment, the first high-temperature portion 65h of the first heat exchanger 60 and the second high-temperature portion 75h of the second heat exchanger 70 face each other, and the first low-temperature portion 65l of the first heat exchanger 60 and the second low-temperature portion 75l of the second heat exchanger 70 face each other (see Figures 3(A) and 3(B)). As a result, as shown in graphs G1 and G2, the unevenness of the temperature difference between the first heat exchanger 60 and the second heat exchanger 70 is reduced. This makes it possible to suppress the decrease in the thermoacoustic effect in the prime mover 30 and the cooler 40.

[0046] An example of the first heat exchange step in the claims is the step of forming a first high-temperature portion 65h and a first low-temperature portion 65l on one surface 52 of the heat regenerator 50, 51 using the first heat exchangers 60, 61. An example of the second heat exchange step in the claims is the step of forming a second high-temperature portion 75h facing the first high-temperature portion 65h and a second low-temperature portion 75l facing the first low-temperature portion 65l on the other surface 54 of the heat regenerator 50, 51 using the second heat exchangers 70, 71.

[0047] (Effects and Benefits) As described above, in the prime mover 30 and cooler 40 of this embodiment, the first high-temperature portion 65h of the first heat exchangers 60, 61 and the second high-temperature portion 75h of the second heat exchangers 70, 71 face each other, and the first low-temperature portion 65l of the first heat exchangers 60, 61 and the second low-temperature portion 75l of the second heat exchangers 70, 71 face each other (see Figures 3(A) and 3(B)). Therefore, compared to configurations where, for example, the high-temperature portion of the first heat exchangers 60, 61 and the low-temperature portion of the second heat exchangers 70, 71 face each other, or configurations where there is no temperature difference between the first heat exchangers 60, 61 and the second heat exchangers 70, 71, the temperature difference between the first heat exchangers 60, 61 and the second heat exchangers 70, 71 is less uneven. Therefore, according to this embodiment, it is possible to suppress the decrease in thermoacoustic effect caused by uneven temperature differences between the first heat exchangers 60, 61 and the second heat exchangers 70, 71.

[0048] In this embodiment, the first heat exchanger 60 has two first heat transfer tubes 64, and the second heat exchanger 70 has two second heat transfer tubes 74. In the left-side divided region EL and the right-side divided region ER, the first high-temperature portion 65h of the first heat exchanger 60 and the second high-temperature portion 75h of the second heat exchanger 70 face each other, and the first low-temperature portion 65l of the first heat exchanger 60 and the second low-temperature portion 75l of the second heat exchanger 70 face each other. Therefore, compared to a configuration in which, for example, two first heat transfer tubes 64 are connected to form one heat transfer tube, or two second heat transfer tubes 74 are connected to form one heat transfer tube, the length of each heat transfer tube is shorter, and the temperature difference between the ends of the heat transfer tubes 64 and 74 is smaller. Therefore, it is possible to suppress the temperature difference between each heat exchanger 60 and 70 while suppressing the decrease in thermoacoustic effect caused by the uneven temperature difference between the first heat exchanger 60 and the second heat exchanger 70.

[0049] In this embodiment, in the first heat exchanger 60, the first high-temperature portion 65h of the left heat transfer tube 64L and the first high-temperature portion 65h of the right heat transfer tube 64R are arranged adjacent to each other (see Figure 3(A)). Therefore, compared to a configuration where, for example, the first high-temperature portion 65h of the left heat transfer tube 64L and the first low-temperature portion 65l of the right heat transfer tube 64R are adjacent to each other, it is possible to suppress the influence on the temperature of each first heat transfer tube 64 due to heat transfer between the two first heat transfer tubes 64. Furthermore, in the second heat exchanger 70, the second high-temperature portion 75h of the left heat transfer tube 74L and the second high-temperature portion 75h of the right heat transfer tube 74R are arranged adjacent to each other (see Figure 3(B)). Therefore, compared to a configuration where, for example, the second high-temperature portion 75h of the left heat transfer tube 74L and the second low-temperature portion 75l of the right heat transfer tube 74R are adjacent to each other, it is possible to suppress the influence on the temperature of each second heat transfer tube 74 caused by heat transfer between the two second heat transfer tubes 74.

[0050] In this embodiment, the first heat transfer tube 64 and the second heat transfer tube 74 have the same shape. One end of the first heat transfer tube 64 is the inlet for the high-temperature medium F1, and the end of the second heat transfer tube 74 facing the end of the first heat transfer tube 64 is the outlet for the low-temperature medium F2 (see Figures 3(A) and 3(B)). In this configuration, where the first heat transfer tube 64 and the second heat transfer tube 74 have the same shape, the reduction in thermoacoustic effect caused by temperature differences between the first heat exchanger 60 and the second heat exchanger 70 can be suppressed by simply reversing the direction of flow of the high-temperature medium F1 and the low-temperature medium F2.

[0051] <Second Embodiment> Figure 4 is an explanatory diagram showing the configuration of the heat transfer tubes of the first heat exchanger 60a and the second heat exchanger 70a in the second embodiment and the temperature difference between them. Figure 4(A) shows the piping configuration of the first heat transfer tube 64a of the first heat exchanger 60a in an axial S view of the housing piping 23. Figure 4(B) shows the piping configuration of the second heat transfer tube 74a of the second heat exchanger 70a in an axial S view of the housing piping 23. Note that in Figures 4(A) and (B), the frame is simplified and the fins are omitted. Figure 4 also shows a dividing line X that bisects each heat exchanger 60a and 70a left and right in an axial S view of the housing piping 23, and the left dividing region EL and the right dividing region ER.

[0052] As shown in Figure 4(A), multiple first heat transfer tubes 64a are arranged within the frame of the first heat exchanger 60a. Each first heat transfer tube 64a extends linearly in a predetermined direction perpendicular to the axial direction S of the housing piping 23 (the left-right direction in the plane of Figure 4). The multiple first heat transfer tubes 64a are independent of each other and are arranged at equal intervals in a direction perpendicular to the axial direction of the first heat transfer tube 64a (the up-down direction in the plane of Figure 4). The high-temperature medium F1 flows from the left end to the right end of each first heat transfer tube 64a. As the high-temperature medium F1 flows through the first heat transfer tubes 64a, its temperature decreases due to heat exchange with the working gas flowing through the housing piping 23. Therefore, the temperature is highest at the left end of each first heat transfer tube 64a and lowest at the right end (see the white arrow). As a result, the first heat exchanger 60a is formed with a first high-temperature portion 65ah and a first low-temperature portion 65al.

[0053] As shown in Figure 4(B), multiple second heat transfer tubes 74a are arranged within the frame of the second heat exchanger 70a. The multiple second heat transfer tubes 74a are identical in shape to the multiple first heat transfer tubes 64a. However, the low-temperature medium F2 flows in the opposite direction to the high-temperature medium F1. That is, the low-temperature medium F2 flows from the right end to the left end of each second heat transfer tube 74a. As the low-temperature medium F2 flows through the second heat transfer tubes 74a, its temperature rises due to heat exchange with the working gas flowing through the housing piping 23. Therefore, the temperature is highest at the left end of each second heat transfer tube 74a and lowest at the right end (see the white arrow). As a result, a second high-temperature section 75ah and a second low-temperature section 75al are formed in the second heat exchanger 70a.

[0054] Here, the right side of Figure 4 shows the temperatures of the first heat exchanger 60a and the second heat exchanger 70a. Graph G1a shows the temperature of the first heat exchanger 60a in a cross-section perpendicular to the axial direction S of the housing piping 23, and graph G2a shows the temperature of the second heat exchanger 70a in a cross-section perpendicular to the axial direction S of the housing piping 23. In this embodiment, the first high-temperature portion 65ah in the first heat exchanger 60a and the second high-temperature portion 75ah in the second heat exchanger 70a face each other, and the first low-temperature portion 65al in the first heat exchanger 60a and the second low-temperature portion 75al in the second heat exchanger 70a face each other (see Figures 4(A) and 4(B)). As a result, as shown in graphs G1a and G2a, the unevenness of the temperature difference between the first heat exchanger 60a and the second heat exchanger 70a is reduced. This makes it possible to suppress the decrease in thermoacoustic effect in the prime mover 30 and the cooler 40.

[0055] <Third Embodiment> Figure 5 is an explanatory diagram showing the configuration of the heat transfer tubes of the first heat exchanger 60b and the second heat exchanger 70b in the third embodiment and the temperature difference between them. Figure 5(A) shows the piping configuration of the first heat transfer tube 64b in the axial S view of the housing piping 23 for the first heat exchanger 60b. Figure 5(B) shows the piping configuration of the second heat transfer tube 74b in the axial S view of the housing piping 23 for the second heat exchanger 70b. A dividing line Y (dotted line) is shown in Figure 5. This dividing line Y is a line that divides each heat exchanger 60b, 70b into two equal parts vertically in the axial S view of the housing piping 23. Hereinafter, the region above the dividing line Y will be called the "upper dividing region EU", and the region below the dividing line Y will be called the "lower dividing region ED". Note that in Figures 5(A) and (B), the frame is simplified and the fins are omitted.

[0056] As shown in Figure 5(A), a first heat transfer tube 64b is arranged within the frame of the first heat exchanger 60b. The first heat transfer tube 64b has seven main sections 66b and six connecting sections 68b. Each main section 66b extends linearly in a predetermined direction (left-right direction in the plane of Figure 5) perpendicular to the axial direction S of the housing piping 23. In a view of the housing piping 23 in the axial direction S, the seven main sections 66b are arranged at equal intervals in a direction perpendicular to the axial direction of the main section 66b (up-down direction in the plane of Figure 5). The six connecting sections 68b include three left-end connecting sections 68b and three right-end connecting sections 68b. The left-end connecting sections 68b connect the left ends of two adjacent main sections 66b. The right-end connecting sections 68b connect the right ends of two adjacent main sections 66b. The left end connecting section 68b and the right end connecting section 68b are arranged alternately in the vertical direction.

[0057] The high-temperature medium F1 flows from the lower end to the upper end of the first heat transfer tube 64b. As the high-temperature medium F1 flows through the first heat transfer tube 64b, its temperature decreases due to heat exchange with the working gas flowing through the housing piping 23. As a result, the temperature at the lower end of the first heat transfer tube 64b is the highest, and the temperature at the upper end is the lowest (see the white arrow). Consequently, the first heat exchanger 60b forms a first high-temperature section 65bh and a first low-temperature section 65bl.

[0058] The second heat transfer tube 74b has a shape that is the reverse of the second heat transfer tube 74b. However, the low-temperature medium F2 flows in the opposite direction to the high-temperature medium F1. That is, the low-temperature medium F2 flows from the upper end to the lower end of the second heat transfer tube 74b. As the low-temperature medium F2 flows through the second heat transfer tube 74b, its temperature rises due to heat exchange with the working gas flowing through the housing piping 23. As a result, the temperature at the lower end of the second heat transfer tube 74b is the highest, and the temperature at the upper end is the lowest (see the white arrow). Consequently, a second high-temperature section 75bh and a second low-temperature section 75bl are formed in the second heat exchanger 70b.

[0059] Here, the right side of Figure 5 shows the temperatures of the first heat exchanger 60b and the second heat exchanger 70b. Graph G1b shows the temperature of the first heat exchanger 60b in a cross-section perpendicular to the axial direction S of the housing piping 23, and graph G2b shows the temperature of the second heat exchanger 70b in a cross-section perpendicular to the axial direction S of the housing piping 23. In this embodiment, the first high-temperature portion 65bh of the first heat exchanger 60b and the second high-temperature portion 75bh of the second heat exchanger 70b face each other, and the first low-temperature portion 65bl of the first heat exchanger 60b and the second low-temperature portion 75bl of the second heat exchanger 70b face each other (see Figures 5(A) and 5(B)). As a result, as shown in graphs G1b and G2b, the unevenness of the temperature difference between the first heat exchanger 60b and the second heat exchanger 70b is reduced. This makes it possible to suppress the decrease in thermoacoustic effect in the prime mover 30 and the cooler 40.

[0060] <Fourth Embodiment> Figure 6 is an explanatory diagram showing the configuration of the heat transfer tubes of the first heat exchanger 60c and the second heat exchanger 70c in the fourth embodiment and the temperature difference between them. Figure 6(A) shows the piping configuration of the first heat transfer tube 64c for the first heat exchanger 60c in an axial S view of the housing piping 23. Figure 6(B) shows the piping configuration of the second heat transfer tube 74c for the second heat exchanger 70c in an axial S view of the housing piping 23. Figure 6 shows a dividing line Y that bisects each heat exchanger 60c, 70c vertically in an axial S view of the housing piping 23, and the upper dividing region EU and the lower dividing region ED. Note that in Figures 6(A) and (B), the frame is simplified and the fins are omitted.

[0061] As shown in Figure 6(A), multiple first heat transfer tubes 64c are arranged within the frame of the first heat exchanger 60c. Each first heat transfer tube 64c extends linearly in a predetermined direction (left-right direction in the plane of Figure 6) perpendicular to the axial direction S of the housing piping 23. The multiple first heat transfer tubes 64c are independent of each other and are arranged at equal intervals in a direction perpendicular to the axial direction of the first heat transfer tube 64c (up-down direction in the plane of Figure 6). The same number of first heat transfer tubes 64c are arranged in the upper dividing region EU and the lower dividing region ED.

[0062] In the upper divided region EU, the high-temperature medium F1 flows from the right end to the left end of each first heat transfer tube 64c. As the high-temperature medium F1 flows through the first heat transfer tubes 64c, its temperature decreases due to heat exchange with the working gas flowing through the housing piping 23. As a result, the temperature is highest at the right end of each first heat transfer tube 64c and lowest at the left end (see the white arrow). Consequently, a first high-temperature section 65ch and a first low-temperature section 65cl are formed in the upper divided region EU.

[0063] In the lower divided region ED, the high-temperature medium F1 flows from the left end to the right end of each first heat transfer tube 64c. As a result, a first high-temperature portion 65ch and a first low-temperature portion 65cl are formed in the lower divided region ED as well. However, the arrangement of the first high-temperature portion 65ch and the first low-temperature portion 65cl is reversed between the upper divided region EU and the lower divided region ED.

[0064] As shown in Figure 6(B), multiple second heat transfer tubes 74c are arranged within the frame of the second heat exchanger 70c. The multiple second heat transfer tubes 74c are identical in shape to the multiple first heat transfer tubes 64c. However, the low-temperature medium F2 flows in the opposite direction to the high-temperature medium F1. That is, in the upper divided region EU, the low-temperature medium F2 flows from the left end to the right end of each second heat transfer tube 74c. As a result, a second high-temperature portion 75ch and a second low-temperature portion 75cl are formed in the upper divided region EU. In the lower divided region ED, the low-temperature medium F2 flows from the right end to the left end of each second heat transfer tube 74c. As a result, a second high-temperature portion 75ch and a second low-temperature portion 75cl are also formed in the lower divided region ED. However, the arrangement of the second high-temperature portion 75ch and the second low-temperature portion 75cl is reversed between the upper divided region EU and the lower divided region ED.

[0065] Here, the upper right side of Figure 6 shows the temperatures of the first heat exchanger 60c and the second heat exchanger 70c in the upper divided region EU. Graph G1u shows the temperature of the upper divided region EU of the first heat exchanger 60c in a cross-section perpendicular to the axial direction S of the housing piping 23, and graph G2u shows the temperature of the upper divided region EU of the second heat exchanger 70b in a cross-section perpendicular to the axial direction S of the housing piping 23. In this embodiment, in the upper divided region EU, the first high-temperature portion 65ch of the first heat exchanger 60c and the second high-temperature portion 75ch of the second heat exchanger 70c face each other, and the first low-temperature portion 65cl of the first heat exchanger 60c and the second low-temperature portion 75cl of the second heat exchanger 70c face each other (see Figures 6(A) and 6(B)). As a result, as shown in graphs G1u and G2u, the unevenness in the temperature difference between the first heat exchanger 60c and the second heat exchanger 70c in the upper divided region EU is reduced.

[0066] Furthermore, the temperatures of the first heat exchanger 60c and the second heat exchanger 70c in the lower right section of Figure 6 are shown. Graph G1d shows the temperature of the lower section ED of the first heat exchanger 60c in a cross-section perpendicular to the axial direction S of the housing piping 23, and graph G2d shows the temperature of the lower section ED of the second heat exchanger 70b in a cross-section perpendicular to the axial direction S of the housing piping 23. In this embodiment, in the lower section ED, the first high-temperature portion 65ch of the first heat exchanger 60c and the second high-temperature portion 75ch of the second heat exchanger 70c face each other, and the first low-temperature portion 65cl of the first heat exchanger 60c and the second low-temperature portion 75cl of the second heat exchanger 70c face each other (see Figures 6(A) and 6(B)). As a result, as shown in graphs G1d and G2d, the unevenness in the temperature difference between the first heat exchanger 60c and the second heat exchanger 70c in the lower divided region ED is reduced.

[0067] <Other Embodiments> (1) In the above embodiment, the thermoacoustic device 10 was a cooling device, but the thermoacoustic device does not have to be a cooling device. For example, it may be a heating device equipped with a heat pump for heating instead of the cooler 40, or it may be a power generation device equipped with a generator that converts sound waves output from a prime mover into electricity. (2) In the above embodiment, the piping 20 was in the shape of a loop, but the piping may also include branch pipes that branch off from the loop-shaped piping. (3) In the above embodiment, the thermoacoustic device 10 was equipped with one prime mover 30, but the thermoacoustic device may be equipped with multiple prime movers. (4) In the above embodiment, the thermoacoustic device 10 was equipped with two expansion tubes 22, but there may be one or more expansion tubes, and the thermoacoustic device may not be equipped with expansion tubes. (5) In the above embodiment, the heat storage container 50 was disc-shaped, but there are no particular restrictions on the shape of the heat storage container, and it may be, for example, a polygonal plate shape. (6) In the above embodiment, the housing pipe 23 was a pipe in which the inner diameter of the central portion between both ends was larger than that of the main pipe 21. However, there are no particular restrictions on the shape of the portion of the pipe that houses the heat regenerator and heat exchanger; any shape that can house the heat regenerator and heat exchanger is acceptable. (7) In each of the above embodiments, the first heat transfer tube was shaped along one surface 52 of the heat accumulator 50 over its entire length, but it may also be shaped such that at least a portion is inclined with respect to one surface 52 of the heat accumulator 50, or such that a portion is spaced further apart from one surface 52 of the heat accumulator 50 than other portions. Similarly, the second heat transfer tube may also be shaped such that at least a portion is inclined with respect to the other surface 54 of the heat accumulator 50, or such that a portion is spaced further apart from the other surface 54 of the heat accumulator 50 than other portions. (8) In the first embodiment described above, the first heat exchanger 60 may have a shape having three or more first heat transfer tubes 64. The multiple first heat transfer tubes 64 may have different shapes and inner diameters, and the distances between them from one surface 52 of the heat accumulator 50 may also be different. Similarly, the second heat exchanger 70 may have a shape having three or more second heat transfer tubes 74. The multiple second heat transfer tubes 74 may have different shapes and inner diameters, and the distances between them from the other surface 54 of the heat accumulator 50 may also be different. The right heat transfer tube 64R may also have a shape symmetrical to the left heat transfer tube 64L. Furthermore, in the first heat exchanger 60, the first low-temperature portion 65l of the left heat transfer tube 64L and the first low-temperature portion 65l of the right heat transfer tube 64R may be adjacent to each other, or the first high-temperature portion 65h of the left heat transfer tube 64L and the first low-temperature portion 65l of the right heat transfer tube 64R may be adjacent to each other. (9) In the second embodiment described above, at least some of the plurality of first heat transfer tubes 64a may have different shapes, inner diameters, and outer diameters. Similarly, at least some of the plurality of second heat transfer tubes 74a may have different shapes, inner diameters, and outer diameters. Furthermore, the plurality of second heat transfer tubes 74a may have the same shape as the plurality of first heat transfer tubes 64a but different inner diameters and outer diameters, or they may have different shapes from each other. (10) In the third embodiment described above, the second heat transfer tube 74b may have the same shape as the first heat transfer tube 64b, and its open end may face the same direction. The second heat transfer tube 74b may have the same shape as the first heat transfer tube 64b, but with different inner diameters or outer diameters, or they may have different shapes from each other. (11) In the fourth embodiment described above, in the first heat exchanger 60c, the direction in which the high-temperature medium F1 flows to the first heat transfer tube 64c was opposite in the upper divided region EU and the lower divided region ED, but it may be the same direction. Also, in the second heat exchanger 70c, the direction in which the low-temperature medium F2 flows to the second heat transfer tube 74c was opposite in the upper divided region EU and the lower divided region ED, but it may be the same direction. (12) In each of the above embodiments, the heat exchanger was configured to have a high-temperature portion and a low-temperature portion by having heat transfer tubes, but it is not limited to this, for example, the heat exchanger may have a configuration in which a high-temperature portion and a low-temperature portion are formed in the fin portion by having a fin portion arranged in the housing piping and a heater or cooler arranged on the outer circumference of the fin portion. [Explanation of symbols]

[0068] 10: Thermoacoustic device 20: Piping 21: Main pipe 22: Expansion pipe 23: Containing piping 23A: Opening 23B: First straight pipe section 23C: Tapered section 23D: Second straight pipe section 30: Prime mover 40: Cooler 50,51: Heat accumulator 60,61,60a,60b,60c: First heat exchanger 62,72: Frame 64,64a,64b,64c: First heat transfer tube 64L: Left heat transfer tube 64R: Right heat transfer tube 65h,65ah,65bh,65ch: First high-temperature section 65l,65al,65bl,65cl: First low-temperature section 66,66b: Main pipe section 68,68b: Connecting section 70,71,70a,70b,70c: Second heat exchanger 74,74a,74b,74c: Second heat exchanger tube 74L: Left side heat exchanger tube 74R: Right side heat exchanger tube 75h,75ah,75bh,75ch: Second high temperature section 75l,75al,75bl,75cl: Second low temperature section ED: Lower divided area EL: Left side divided area ER: Right side divided area EU: Upper side divided area F1: High temperature medium F2: Low temperature medium P1: Pipe line

Claims

1. An energy converter incorporated into a thermoacoustic device that contains a working gas, which performs energy conversion between thermal energy and acoustic energy, A heat storage device having one surface and another surface, and having a plurality of through passages that penetrate from one surface to the other surface, A first heat exchanger is positioned opposite to one of the heat storage devices, A second heat exchanger is positioned opposite the other side of the heat storage device, Equipped with, The first heat exchanger described above is configured to have a first high-temperature portion and a first low-temperature portion with different temperatures. The second heat exchanger described above is configured to form a second high-temperature section and a second low-temperature section with different temperatures. The first high-temperature portion of the first heat exchanger and the second high-temperature portion of the second heat exchanger face each other, and the first low-temperature portion of the first heat exchanger and the second low-temperature portion of the second heat exchanger face each other, The first heat exchanger has a configuration in which a first high-temperature portion and a first low-temperature portion are formed by having a first heat transfer tube through which a first fluid flows. The second heat exchanger has a second heat transfer tube through which a second fluid, which is at a lower temperature than the first fluid, flows, thereby forming a second high-temperature portion and a second low-temperature portion. The first heat exchanger has a plurality of the first heat transfer tubes, The second heat exchanger has a plurality of the second heat transfer tubes, The first high-temperature portion of each first heat transfer tube and the second high-temperature portion of each second heat transfer tube face each other, and the first low-temperature portion of each first heat transfer tube and the second low-temperature portion of each second heat transfer tube face each other. In the first heat exchanger, at least two adjacent first heat transfer tubes are positioned such that one of the first high-temperature portion and the first low-temperature portion is closer to each other than the other portion. In the second heat exchanger, at least two adjacent second heat transfer tubes are positioned such that one of the second high-temperature portion and the second low-temperature portion is closer to each other than the other portion. Energy converter.

2. An energy converter according to Claim 1, The first heat transfer tube and the second heat transfer tube are identical in shape. One end of the first heat transfer tube is the inlet for the first fluid, and the end of the second heat transfer tube that faces the one end of the first heat transfer tube is the outlet for the second fluid. Energy converter.

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