Energy converter and thermoacoustic device

Abstract

This energy converter is provided in a thermoacoustic device, is disposed inside a piping in which working gas is sealed, and comprises a heat accumulator and two heat exchangers that are disposed on both sides of the heat accumulator and exchange heat between a medium supplied from the outside of the piping and the working gas passing through the inside of the piping. The heat accumulator comprises a central heat accumulator and two end heat accumulators that are disposed between the central heat accumulator and the two heat exchangers. The central heat accumulator has a plurality of partition walls that extend in the extension direction of the piping, and a plurality of central flow paths that penetrate in the extension direction of the piping and are independent of each other by being divided by the partition walls. Each of the two end heat accumulators is a member in which meshes obtained by weaving a plurality of wires are laid in the extension direction of the piping and has end flow paths that are formed by interconnection of a plurality of gaps between the wires.

Description

Energy converters and thermoacoustic devices

[0001] The technologies disclosed herein relate to energy converters and thermoacoustic devices.

[0002] A thermoacoustic device comprises piping containing a working gas that propagates sound waves, and a prime mover (energy converter) incorporated into this piping. The energy converter includes a heat accumulator with numerous through-holes (flow channels) and heat exchangers positioned at both ends of the heat accumulator. Such an energy converter converts thermal energy into acoustic energy (sound waves) or acoustic energy into thermal energy, for example, by the self-excited vibration of the working gas inside the flow channels due to a temperature gradient generated between the ends of the heat accumulator. (See Patent Documents 1, 2, and 3).

[0003] In the thermoacoustic device described in Patent Document 2, in a configuration where the end face of the heat exchanger is in direct contact with the end face of the heat accumulator, the end face of the fins of the heat exchanger blocks the opening of the flow path. As a result, self-excited oscillation of the working gas does not occur inside the blocked flow path. To solve this problem, Patent Document 2 provides a thermoacoustic device equipped with a wave spring placed between the first heat exchanger and the heat accumulator. With this configuration, a gap is provided between the first heat exchanger and the heat accumulator through the hole in the center of the wave spring, so that the end face of the fins provided on the first heat exchanger does not block the opening of the flow path of the heat accumulator. As a result, thermal energy can be converted into acoustic energy more efficiently in the heat accumulator.

[0004] In the thermoacoustic device described in Patent Document 3, when a regenerator is disposed between the heating-side heat exchanger and the cooling-side heat exchanger, there is a risk that both ends of some of the fine pores (flow paths) will be blocked, creating a space through which the working fluid cannot pass. This space forms a dead space that does not function as a regenerator and significantly degrades the performance of the regenerator. To solve this problem, in the thermoacoustic device of Patent Document 3, the regenerator includes a plurality of fine pores and a gap formed across the plurality of fine pores. The gap forms a ventilation flow path that connects the plurality of fine pores and contributes to reducing the dead space. That is, a recirculation flow path is formed in which the working fluid flows into the fine pores that were the dead space through the gap and then flows out again through the original fine pores, enabling most of the fine pores that were the dead space to function as a regenerator.

[0005] International Publication No. 2015 / 115005 Japanese Unexamined Patent Application Publication No. 2022-44193 Japanese Unexamined Patent Application Publication No. 2015-21671

[0006] In the above thermoacoustic device, there was room for improvement in suppressing the performance degradation of the regenerator.

[0007] This specification discloses a technique capable of solving the above-described problems.

[0008] The technology disclosed herein can be realized, for example, in the following forms: (1) An energy converter disclosed herein is provided in a thermoacoustic device and is located inside a pipe filled with a working gas, and comprises a heat accumulator and two heat exchangers located on either side of the heat accumulator, which exchange heat between a medium supplied from outside the pipe and the working gas passing inside the pipe, wherein the heat accumulator comprises a central heat accumulator and two end heat accumulators located between the two heat exchangers and the central heat accumulator, the central heat accumulator having a plurality of partition walls extending in the direction of extension of the pipe and a plurality of central flow paths penetrating in the direction of extension of the pipe and being independent of each other by being partitioned by the partition walls, and each of the two end heat accumulators is a member in which a plurality of meshes woven from a plurality of wires are stacked in the direction of extension of the pipe, and has an end flow path formed by the connection of a plurality of gaps between the wires.

[0009] According to the above configuration, the performance degradation of the heat storage device is suppressed.

[0010] (2) In the energy converter described in (1) above, each of the two end heat accumulators may be arranged in a compressed state between each of the two heat exchangers and the central heat accumulator.

[0011] With this configuration, the end accumulator functions not only as part of the accumulator but also as a buffer. This makes it easy to maintain contact between the accumulator and the heat exchanger.

[0012] (3) In the energy converter described in (2) above, the central heat storage unit may be made of ceramics.

[0013] When the central heat storage unit is made of ceramics, end heat storage units that also function as buffers are suitably applied.

[0014] (4) A thermoacoustic apparatus disclosed herein comprises an energy converter as described in any one of (1) to (3) above, and piping in which the energy converter is housed and in which a working gas can be sealed.

[0015] This configuration suppresses the degradation of the heat storage unit's performance.

[0016] The technologies disclosed herein can be implemented in various forms, for example, in the form of an energy converter, a thermoacoustic device equipped with an energy converter, and a method for manufacturing the same.

[0017] A perspective view showing a partially cutaway thermoacoustic device of the embodiment. A cross-sectional view showing the thermoacoustic device of the embodiment cut at the position indicated by line II-II in Figure 1. A schematic front view showing the configuration of the first heat exchanger of the embodiment. A cross-sectional view showing the first heat exchanger of the embodiment cut at the position indicated by line IV-IV in Figure 3. A schematic perspective view showing the configuration of the central heat accumulator of the embodiment. A schematic exploded perspective view showing the configuration of the first end heat accumulator of the embodiment. A schematic partially enlarged cross-sectional view showing how acoustic energy is transmitted inside the energy converter of the embodiment.

[0018] The embodiments will be described with reference to Figures 1 to 7. The thermoacoustic device 100 of this embodiment is a cooling device that uses acoustic energy to maintain the temperature of an object at a temperature lower than room temperature.

[0019] As shown in Figure 1, the thermoacoustic device 100 includes piping 200 and a prime mover 400 (an example of an energy converter) and a cooler 600 (an example of an energy converter) arranged inside the piping 200.

[0020] As shown in Figure 1, the piping 200 comprises a plurality of main pipes 210, 220, 230, and 240, a plurality of expansion pipes 250 and 260, a prime mover pipe 270, and a cooler pipe 280. In this embodiment, the main pipes 210, 220, 230, and 240, the expansion pipes 250 and 260, the prime mover pipe 270, and the cooler pipe 280 are made of metal. A prime mover 400 is housed inside the prime mover pipe 270, and a cooler 600 is housed inside the cooler pipe 280.

[0021] A loop-shaped conduit 290 is formed by the main pipes 210, 220, 230, and 240, the expansion pipes 250 and 260, the prime mover piping 270, and the cooler piping 280. The conduit 290 is capable of containing a working gas. The working gas is not particularly limited as long as it is a gas that can transmit sound waves, and an inert gas consisting of helium, argon, or a mixture of helium and argon, or air is preferably used.

[0022] Multiple main pipes 210, 220, 230, and 240 each have a constant inner diameter and are pipes of the same diameter to each other. Main pipe 210 is the pipe that connects the prime mover piping 270 and the expansion pipe 250. Main pipe 220 is the pipe that connects the two expansion pipes 250 and 260. Main pipe 230 is the pipe that connects the expansion pipe 260 and the cooling machine piping 280. Main pipe 240 is the pipe that connects the cooling machine piping 280 and the prime mover piping 270.

[0023] The two expansion tubes 250 and 260, as shown in Figure 1, each have openings at both ends, and the inner diameter of the central portion between the ends is larger than that of the main tubes 210, 220, 230, and 240.

[0024] As shown in Figure 1, the prime mover piping 270 is a pipe having openings at both ends, with the inner diameter of the central portion between the ends being larger than that of the main pipes 210, 220, 230, and 240. As shown in Figure 2, the prime mover piping 270 includes a high-temperature pipe 271 that houses the first heat exchanger 510 and a low-temperature pipe 275 that houses the second heat exchanger 540.

[0025] The high-temperature pipe 271 is a pipe having openings at both ends. As shown in Figure 2, the high-temperature pipe 271 comprises a small straight section 272, a tapered section 273, a large straight section 274, and a flange 310.

[0026] The small straight pipe section 272 is a short, straight tubular section located at one end of the high-temperature pipe 271, and has an outer and inner diameter approximately equal to that of the main pipes 210, 220, 230, and 240. The large straight pipe section 274 is located at the other end of the high-temperature pipe 271 and is a short, straight tubular section having a larger inner diameter than the small straight pipe section 272. The tapered section 273 connects the small straight pipe section 272 and the large straight pipe section 274 and is a tubular section that narrows in diameter from the large straight pipe section 274 towards the small straight pipe section 272. The flange 310 is an annular section that extends outward from the other end of the high-temperature pipe 271.

[0027] The low-temperature pipe 275 is a pipe having openings at both ends. As shown in Figure 2, the low-temperature pipe 275 comprises a small straight section 276, a tapered section 277, a large straight section 278, and a flange 320. The small straight section 276, the tapered section 277, the large straight section 278, and the flange 320 have the same shape as the small straight section 272, the tapered section 273, the large straight section 274, and the flange 310 of the high-temperature pipe 271, respectively.

[0028] The flange 320 of the low-temperature pipe 275 and the flange 310 of the high-temperature pipe 271 are fastened together by bolts. An insulating member 330 may be sandwiched between the two flanges 310 and 320.

[0029] The configuration of the cooling system piping 280 is the same as that of the prime mover piping 270, so the explanation will be omitted.

[0030] The prime mover 400 is a device for converting thermal energy into acoustic energy (sound waves) and is located inside the prime mover piping 270. As shown in Figures 1 and 2, the prime mover 400 includes a heat accumulator 410, a first heat exchanger 510 (an example of a heat exchanger), and a second heat exchanger 540 (an example of a heat exchanger). The first heat exchanger 510, the heat accumulator 410, and the second heat exchanger 540 are arranged in this order.

[0031] As shown in Figure 2, the first heat exchanger 510 is located inside the large straight pipe section 274 of the high-temperature piping 271. The first heat exchanger 510 comprises a first heat sink 520 and a first heat transfer tube 530.

[0032] As shown in Figure 3, the first heat sink 520 comprises a cylindrical support ring 521 having openings at both ends, and a plurality of fins 522 arranged inside the support ring 521. Each fin 522 is flat. The plurality of fins 522 are arranged parallel to each other inside the support ring 521. There is a gap between adjacent fins 522, through which the working gas can pass. The first heat sink 520 is made of, for example, metal. The metal used for the first heat sink 520 may be, for example, copper, aluminum, or stainless steel. The first heat sink 520 is arranged inside the large straight pipe section 274, with the fins 522 oriented along the axial direction of the prime mover piping 270.

[0033] The first heat transfer tube 530 is a tube that extends through the fins 522. A high-temperature medium (an example of a medium) supplied from outside the piping 200 can pass through the inside of the first heat transfer tube 530, and heat exchange takes place between the working gas near the first heat exchanger 510 and the high-temperature medium. As the high-temperature medium, for example, a high-temperature medium oil heated by waste heat from a factory can be used. The temperature of the high-temperature medium oil is, for example, about 200-400°C.

[0034] As shown in Figure 2, the second heat exchanger 540 is located inside the large straight pipe section 278 of the low-temperature piping 275. The second heat exchanger 540 comprises a second heat sink 550 and a second heat transfer tube 560. The configurations of the second heat sink 550 and the second heat transfer tube 560 are the same as those of the first heat sink 520 and the first heat transfer tube 530, respectively, so the same reference numerals are used for the same components and detailed explanations are omitted.

[0035] A low-temperature medium (an example of a medium) supplied from outside the piping 200 can pass through the inside of the second heat transfer tube 560. The low-temperature medium is colder than the high-temperature medium circulating inside the first heat transfer tube 530. The working gas near the second heat exchanger 540 becomes colder than the high-temperature medium through heat exchange with the low-temperature medium. In this embodiment, room temperature water is used as the low-temperature medium.

[0036] As shown in Figure 2, the heat accumulator 410 comprises a central heat accumulator 420, a first end heat accumulator 430 (an example of end heat accumulators), and a second end heat accumulator 440 (an example of end heat accumulators).

[0037] As shown in Figures 5 and 7, the central heat storage unit 420 is a thick disc having a first opening surface S1 facing the first heat exchanger 510 and a second opening surface S2 facing the second heat exchanger 540. The first opening surface S1 and the second opening surface S2 are parallel to each other.

[0038] The central heat accumulator 420 has multiple central passages 422 that open to a first opening surface S1 and a second opening surface S2 and penetrate between the two opening surfaces S1 and S2. Working gas can pass through the interior of each central passage 422. Each central passage 422 is separated from other central passages 422 by a partition wall 421 that extends from the first opening surface S1 to the second opening surface S2. Each central passage 422 is an independent opening. In other words, the multiple central passages 422 are not connected to each other inside the central heat accumulator 420, and working gas cannot pass between them. The central heat accumulator 420 is positioned such that the first opening surface S1 and the second opening surface S2 are perpendicular to the extending direction of the prime mover piping 270. In other words, the partition wall 421 extends in the extending direction of the prime mover piping 270, and the central passages 422 penetrate in the extending direction of the prime mover piping 270.

[0039] The central heat accumulator 420 is made of, for example, ceramics. The ceramic material for the central heat accumulator 420 may be, for example, cordierite, mullite, aluminum titanate, alumina, zirconia, silicon nitride, or silicon carbide. The central heat accumulator 420 may be formed, for example, by extrusion molding.

[0040] As shown in Figure 2, the first end condenser 430 is positioned between the central condenser 420 and the first heat exchanger 510. As shown in Figure 6, the first end condenser 430 is a laminate in which a plurality of meshes 431 are stacked in the direction of extension of the prime mover piping 270. Each mesh 431 is a mesh-like member in which a plurality of wires 432 are woven together, and has a plurality of gaps 433 regularly arranged between the wires 432. In this embodiment, each mesh 431 has a circular outer shape. The plurality of meshes 431 have approximately equal outer diameters and are stacked with their outer edges aligned. As shown in Figure 7, the first end condenser 430 has a third opening surface S3 and a fourth opening surface S4 opposite to the third opening surface S3. The third opening surface S3 is the surface of the mesh 431 positioned at one end of the first end condenser 430 that is opposite to other adjacent meshes 431. The fourth opening surface S4 is the surface of the mesh 431 located at the other end of the first end heat storage unit 430 that is opposite to other adjacent meshes 431.

[0041] As shown in Figure 7, the first end heat storage unit 430 has an end flow channel 434 inside, which is arranged like a mesh by the gaps 433 of each mesh 431 connecting with each other. The end flow channel 434 has multiple openings on the third opening surface S3 and the fourth opening surface S4, through which the working gas can pass.

[0042] The first end heat accumulator 430 is made of metal, for example. The metal used for the wire 432 may be stainless steel, for example.

[0043] The first end heat accumulator 430 is positioned in a compressed state between the central heat accumulator 420 and the first heat sink 520. The compressed state is a state in which the distance between the third opening surface S3 and the fourth opening surface S4 is smaller than in the natural state in which no external force is applied to the stacked meshes 431.

[0044] The third opening surface S3 of the first end heat accumulator 430 is in contact with the first opening surface S1 of the central heat accumulator 420. In the present embodiment, the third opening surface S3 is in contact with the entire surface of the first opening surface S1. The edge of each fin 522 provided in the first heat sink 520 is in contact with the fourth opening surface S4 of the first end heat accumulator 430.

[0045] The second end heat accumulator 440 is disposed between the central heat accumulator 420 and the second heat exchanger 540. Since the configuration of the second end heat accumulator 440 is the same as that of the first end heat accumulator 430, the same components are denoted by the same reference numerals and the description thereof is omitted. The third opening surface S3 of the second end heat accumulator 440 is in contact with the second opening surface S2 of the central heat accumulator 420. The edge of each fin 522 provided in the second heat sink 550 is in contact with the fourth opening surface S4 of the second end heat accumulator 440.

[0046] The cooler 600 (an example of an energy conversion machine) is a heat pump that generates a temperature gradient when acoustic energy generated by the prime mover 400 is input thereto and maintains the temperature of an object at a temperature lower than the normal temperature. As shown in FIG. 1, it is disposed inside the cooler piping 280. The cooler 600 includes a heat accumulator 610, a first heat exchanger 710 (an example of a heat exchanger) and a second heat exchanger 740 (an example of a heat exchanger) respectively disposed on both sides of the heat accumulator 610. The heat accumulator 610, and the heat exchangers 710, 740 provided in the cooler 600 have the same configuration as the heat accumulator 410, and the heat exchangers 510, 540 provided in the prime mover 400. A medium at a constant temperature (water at normal temperature in the present embodiment) can pass through the heat transfer tubes provided in the first heat exchanger 710, and the working gas in the vicinity of the first heat exchanger 710 becomes a temperature of about normal temperature. The heat transfer tubes provided in the second heat exchanger 740 are connected to a heat exchanger provided in an external cooling facility, and a refrigerant can circulate inside the heat transfer tubes.

[0047] When operating the thermoacoustic device 100, a high-temperature medium is flowed through the first heat transfer tube 530. Then, the heat of the high-temperature medium is transmitted to the fins 522 provided on the first heat sink 520, and further transmitted to the working gas. That is, heat exchange is performed between the high-temperature medium and the working gas. Thereby, the temperature of the working gas near the first end heat accumulator 430 is adjusted to approach the temperature of the high-temperature medium. Also, normal-temperature water as a low-temperature medium is flowed through the second heat transfer tube 560. Then, the temperature of the low-temperature medium is transmitted to the fins 522 provided on the second heat sink 550, and further transmitted to the working gas. That is, heat exchange is performed between the low-temperature medium and the working gas. Thereby, the temperature of the working gas near the second end heat accumulator 440 is adjusted to approach the normal temperature.

[0048] Due to the actions of such heat exchangers 510 and 540, a temperature gradient occurs between both ends of the heat accumulator 410. Then, the working gas inside the flow paths 422 and 434 becomes unstable and starts to vibrate. Acoustic energy (sound waves) is generated by this vibration. The generated acoustic energy is output from the heat accumulator 410 and transmitted through the gaps between the fins 522 provided on the first heat exchanger 510 and the working gas existing inside the pipeline 290, and reaches the cooler 600 (see the arrow in FIG. 1).

[0049] When the acoustic energy transmitted by the working gas is input to the heat accumulator 610 provided in the cooler 600, a temperature gradient occurs between one surface facing the first heat exchanger 710 and the other surface facing the second heat exchanger 740. Since normal-temperature water is flowed through the first heat exchanger 710 disposed on the input side of the acoustic energy in the cooler 600, the temperature of the working gas near the second heat exchanger 740 in the heat accumulator 610 is adjusted to a temperature lower than the normal temperature by the amount of the generated temperature gradient. Heat exchange is performed between the working gas at a temperature lower than the normal temperature and the refrigerant, and the refrigerant at a low temperature is supplied to an external cooling facility to cool the object.

[0050] Generally, it is believed that the energy conversion efficiency decreases as the distance between the heat accumulator and the heat exchanger increases. For this reason, in conventional thermoacoustic devices, the heat exchanger was often in contact with the heat accumulator. However, if the heat accumulator has multiple through-holes that are independent of each other, and the heat accumulator and heat exchanger come into contact, some of the openings of the through-holes may be blocked by the heat exchanger. In such cases, self-excited vibration of the working gas will not occur inside the blocked through-holes, and the energy conversion efficiency will decrease. To solve this problem, it is conceivable to place the heat accumulator and heat exchanger with a small gap between them, as long as it does not reduce the energy conversion efficiency. However, it is extremely difficult to install the heat exchanger with a gap small enough to avoid hindering energy conversion while considering dimensional tolerances.

[0051] In the prime mover 400 of this embodiment, as described above, the first end heat accumulator 430 has an end flow channel 434 inside which the gaps 433 of each mesh 431 are interconnected, forming a network. Therefore, as shown in Figure 7, even if the fins 522 come into contact with the end heat accumulators 430 and 440 and block a part of the opening of the end flow channel 434, the internal space of the end flow channel 434 does not become a dead space where self-excited vibration of the working gas occurs. As a result, the performance degradation of the heat accumulator 410 is suppressed.

[0052] In the prime mover 400 of this embodiment, the end heat accumulators 430 and 440 are laminates formed by stacking multiple meshes 431. Each mesh 431 is a component in which multiple wires 432 are woven together, and has multiple gaps 433 arranged between the wires 432. This configuration facilitates the manufacture of end heat accumulators 430 and 440 having end flow channels 434 inside. In addition, since the end heat accumulators 430 and 440 are arranged in a compressed state, they function not only as part of the heat accumulator 410 but also as a buffer. This absorbs variations in the dimensions of the central heat accumulator 420 and heat sinks 520 and 550 due to manufacturing tolerances, as well as dimensional changes due to the thermal expansion coefficient between the central heat accumulator 420 and the heat sinks 520 and 550, and easily maintains contact between the heat accumulator 410 and the heat exchangers 510 and 540. Furthermore, the cushioning function of the end heat accumulators 430 and 440 suppresses vibrations of the central heat accumulator 420 inside the piping 200 caused by the generation of acoustic energy, thereby preventing damage to the central heat accumulator 420.

[0053] In the prime mover 400 of this embodiment, the central heat accumulator 420 is made of ceramics. Compared to components made of other materials such as metal or resin, ceramic components are more susceptible to damage when external forces are applied. In such cases, end heat accumulators 430 and 440, which also function as cushioning materials, are suitably applied.

[0054] The cooler 600 has the same configuration as the prime mover 400 and is similar to the prime mover 400 in that it is a device that converts energy between thermal energy and acoustic energy by the temperature gradient between the ends of the heat accumulator 610. Therefore, the cooler 600 also produces the same effects as the prime mover 400.

[0055] As described above, the thermoacoustic device 100 of this embodiment comprises a prime mover 400, a cooler 600, and piping 200. The piping 200 houses the prime mover 400 and the cooler 600 inside, and is capable of sealing in working gas. The prime mover 400 comprises a heat accumulator 410 and two heat exchangers 510 and 540. The first heat exchanger 510 exchanges heat between a high-temperature medium supplied from outside the piping 200 and working gas passing through the inside of the piping 200. The second heat exchanger 540 exchanges heat between a low-temperature medium supplied from outside the piping 200 and working gas passing through the inside of the piping 200. The heat accumulator 410 comprises a central heat accumulator 420 and two end heat accumulators 430 and 440. The two end condensers 430 and 440 are respectively positioned between the central condenser 420 and the two heat exchangers 510 and 540. The central condenser 420 has a plurality of partition walls 421 extending in the direction of extension of the piping 200, and a plurality of central flow channels 422 that penetrate in the direction of extension of the piping 200 and are independent of each other by being partitioned by the partition walls 421. Each of the two end condensers 430 and 440 is a member in which a plurality of meshes 431, made of a plurality of wires 432 woven together, are stacked in the direction of extension of the piping 200, and has an end flow channel 434 formed by the connection of a plurality of gaps 433 between the wires 432.

[0056] According to the above configuration, the performance degradation of the heat storage unit 410 is suppressed. The same applies to the heat storage unit 610 provided in the cooler 600.

[0057] In the prime mover 400 of this embodiment, each of the end heat accumulators 430 and 440 is positioned in a compressed state between the two heat exchangers 510 and 540 and the central heat accumulator 420.

[0058] With this configuration, the end heat accumulators 430 and 440 function not only as part of the heat accumulator 410 but also as buffers. This makes it easy to maintain contact between the heat accumulator 410 and the heat exchangers 510 and 540. The same applies to the heat accumulator 610 provided in the cooler 600.

[0059] In the prime mover 400 of this embodiment, the central heat accumulator 420 is made of ceramics. The same applies to the cooler 600. When the central heat accumulator 420 is made of ceramics, end heat accumulators 430 and 440, which also function as buffers, are suitably applied. The same applies to the heat accumulator 610 provided in the cooler 600.

[0060] (Modifications) The technology disclosed herein is not limited to the embodiments described above, and can be modified in various forms without departing from its essence, for example, the following modifications are possible: (1) The number of meshes provided in the end condenser is appropriately selected in the range of several to several dozen, taking into consideration the dimensional tolerances of the condenser and heat exchanger and the compressed state after assembly. (2) The two end condensers provided on both sides of the central condenser may have different numbers of meshes. (3) In the above embodiment, the thermoacoustic device 100 was equipped with a prime mover 400 and a cooler 600, but the thermoacoustic device may be equipped with only one energy converter or with three or more. (4) In the above embodiment, the pipeline 290 was loop-shaped, but the pipeline may be equipped with branch lines branching off from the loop-shaped pipeline, for example. (5) In the above embodiment, the thermoacoustic device 100 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 a cooler 600, or it may be a power generation device equipped with a generator that converts sound waves output from a prime mover into electricity.

[0061] 100: Thermoacoustic device 200: Piping 210, 220, 230, 240: Main pipe 250, 260: Expanding pipe 270: Piping for prime mover 271: High-temperature piping 272: Small straight pipe section 273: Tapered section 274: Large straight pipe section 275: Low-temperature piping 276: Small straight pipe section 277: Tapered section 278: Large straight pipe section 280: Piping for cooler 290: Pipeline 310, 320: Flange 330: Insulation material 400: Prime mover (energy converter) 410: Heat accumulator 420: Central heat accumulator 421: Partition wall 422: Central flow path 430: First end heat accumulator (end heat accumulator) 431: Mesh 432: Wire 433: Gap 434: End flow path 440: Second end heat accumulator (end heat accumulator) 510: First heat exchanger (heat exchanger) 520: First heat sink 521: Support ring 522: Fin 530: First heat transfer tube 540: Second heat exchanger (heat exchanger) 550: Second heat sink 560: Second heat transfer tube 600: Cooler (energy converter) 610: Heat accumulator 710: First heat exchanger (heat exchanger) 740: Second heat exchanger (heat exchanger) S1: First opening surface S2: Second opening surface S3: Third opening surface S4: Fourth opening surface

Claims

1. An energy converter provided in a thermoacoustic device and disposed inside a pipe containing a working gas, comprising: a heat accumulator; two heat exchangers disposed on both sides of the heat accumulator and exchanging heat between a medium supplied from outside the pipe and the working gas passing through the inside of the pipe, wherein the heat accumulator comprises: a central heat accumulator; and two end heat accumulators disposed between the two heat exchangers and the central heat accumulator, wherein the central heat accumulator has: a plurality of partition walls extending in the direction of extension of the pipe; a plurality of central flow paths penetrating in the direction of extension of the pipe and separated from each other by the partition walls, and each of the two end heat accumulators is a member in which a plurality of meshes woven from a plurality of wires are stacked in the direction of extension of the pipe, and has end flow paths formed by the connection of a plurality of gaps between the wires.

2. An energy converter according to claim 1, wherein each of the two end heat accumulators is positioned in a compressed state between each of the two heat exchangers and the central heat accumulator.

3. An energy converter according to claim 2, wherein the central heat storage unit is made of ceramics.

4. A thermoacoustic device comprising: an energy converter according to any one of claims 1 to 3; and piping in which the energy converter is housed and in which a working gas can be sealed.

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