WO2024075356A1

WO2024075356A1 - Heat transport device and furnace

Info

Publication number: WO2024075356A1
Application number: PCT/JP2023/025325
Authority: WO
Inventors: 祐樹上田; 和行吉岡
Original assignee: 国立大学法人東京農工大学; 昭電工業株式会社
Priority date: 2022-10-06
Filing date: 2023-07-07
Publication date: 2024-04-11

Abstract

[Problem] To simultaneously achieve the following goals in a heat transport device that uses thermoacoustic self-excited oscillation. (A) Increase the heat transport quantity during heat transport that uses self-excited oscillation. (B) Make it possible to adjust the heat transport quantity. (C) Increase the serviceability of the heat transport device. [Solution] A heat transport device (1) according to the present invention uses thermoacoustic self-excited oscillation and comprises a container (11) that can be provided so as to span between the interior and the exterior of a high-temperature heat source (for example, a furnace (F)) and has, in the interior thereof, a pipe passage (11P) in which both end sections (first end section (11E1), second end section (11E2)) can be substantially blocked. The interior of the pipe passage (11P) can have a working fluid enclosed therein. A pressure control means (15) that can control the pressure of the working fluid is further provided. The pressure control means (15) has a first pressure control part that can control the pressure of the working fluid such that a thermal accumulator (13) weakens self-excited oscillation in response to a command to reduce the heat transport quantity, and a second pressure control part that can control the pressure of the working fluid such that the thermal accumulator (13) strengthens self-excited oscillation in response to a command to increase the heat transport quantity.

Description

Heat Transport Devices and Furnaces

The present invention relates to a heat transport device and a furnace.

Various means are used to transport heat from high-temperature heat sources such as furnaces. One of the functions required for such means is the ability to adjust the amount of heat transported.

As a means for transporting heat from a high-temperature heat source, Patent Document 1 describes a container arranged to straddle the high-temperature heat source and a low-temperature heat bath that is colder than the high-temperature heat source, with a gas sealed in a closed space and a pipeline formed inside with both ends closed; a heat accumulator arranged within the pipeline, with pores formed to connect both ends and insulated from the outside of the container; a first heat exchanger arranged within the pipeline adjacent to the high-temperature heat source end of the heat accumulator, which transfers heat from the high-temperature heat source to the heat accumulator; A heat transport device is disclosed that includes a second heat exchanger that is provided adjacent to the low-temperature heat bath end and transfers heat from the heat accumulator to the low-temperature heat bath, the heat accumulator is centered on the pipe line at a position 12.5% to 25% of the pipe line length from the high-temperature heat source end of the pipe line, is disposed at the low-temperature heat bath end of the container so as to be able to move forward and backward inside the container, and has an adjustment means that enters the container and changes the waveform of the standing wave generated in the pipe line by thermoacoustic self-excited waves.

Patent Document 1 makes it possible to provide a heat transport device that is highly safe and can be introduced and used at low cost.

Patent No. 6807087

Incidentally, it is known that the performance of various devices using thermoacoustics can be improved by increasing the pressure of the working fluid above normal pressure.

The adjustment means in Patent Document 1 is disposed inside the container so that it can freely move back and forth. Therefore, Patent Document 1 requires a drive source for moving the adjustment means back and forth. If such a drive source is provided inside the container, the internal structure of the heat transport device will become complicated, and there is a concern that maintenance of the heat transport device will become difficult.

Furthermore, when such a driving source is provided outside the container, there is a concern that the working fluid may leak from around the transmission means that transmits power from the driving source to the adjustment means. In particular, when the pressure of the working fluid is higher than normal pressure, such leakage may reduce the pressure of the working fluid. This may result in a decrease in the performance of the heat transport device.

An object of the present invention is to achieve both of the following objectives in a heat transport device using thermoacoustic self-excited vibration.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

As a result of extensive research into solving the above problems, the inventors discovered that the above object can be achieved by providing a pressure control means for the working fluid that can perform pressure control to weaken self-excited oscillation in response to a command to reduce heat transport, and that can perform pressure control to strengthen self-excited oscillation in response to a command to increase heat transport, and thus completed the present invention. Specifically, the present invention provides the following.

The invention relating to the first feature comprises a container having a pipe therein that can be arranged to straddle a high-temperature heat source and an exterior of the high-temperature heat source, both ends of which can be substantially closed, the inside of the pipe can be filled with a working fluid, a first heat exchanger, a heat accumulator, and a second heat exchanger are arranged in this order from the first end of the pipe to the second end, the first heat exchanger is arranged in a position where it can transfer heat from the high-temperature heat source to the working fluid, and the heat accumulator connects the periphery of the first heat exchanger of the pipe to the periphery of the second heat exchanger of the pipe. The present invention provides a heat transport device having a gap that can generate thermoacoustic self-excited vibrations, and further including a pressure control means capable of controlling the pressure of the working fluid, the pressure control means including a first pressure control unit that can control the pressure of the working fluid so that the heat accumulator weakens the self-excited vibration in response to a command to reduce the amount of heat transport, and a second pressure control unit that can control the pressure of the working fluid so that the heat accumulator strengthens the self-excited vibration in response to a command to increase the amount of heat transport, and the second heat exchanger can transfer heat of the working fluid to the outside of the high-temperature heat source.

According to the first aspect of the invention, the working fluid on the first heat exchanger side of the heat storage unit is at a higher temperature than the working fluid inside the heat storage unit due to the heat transferred from the high-temperature heat source to the first heat exchanger.

Furthermore, according to the invention relating to the first feature, the working fluid on the second heat exchanger side of the heat storage device becomes colder than the working fluid inside the heat storage device due to the heat transferred by the second heat exchanger to the heat medium outside the high-temperature heat source.

Therefore, according to the first aspect of the invention, the working fluid around the heat accumulator has a temperature gradient in a direction along the piping of the heat accumulator. This enables the heat accumulator to generate thermoacoustic self-excited vibrations according to the relationship between the temperature gradient of the working fluid along this direction and the pressure of the working fluid. This self-excited vibration promotes heat transport from the periphery of the first heat exchanger to the periphery of the second heat exchanger in the piping.

According to the first aspect of the invention, pressure control is possible to weaken the self-excited vibration in response to a command to reduce the amount of heat transport. As a result, the first aspect of the invention can achieve both "(A) improving the amount of heat transport in heat transport using self-excited vibration" and "(B) making the amount of heat transport adjustable" in the sense that adjustment to reduce the amount of heat transport is possible.

Furthermore, according to the invention relating to the first characteristic, it is possible to control the pressure of the working fluid so as to strengthen the self-excited vibration in response to a command to increase the amount of heat transport. As a result, the invention relating to the first characteristic can achieve both "(A) an improvement in the amount of heat transport in heat transport using self-excited vibration" and "(B) making the amount of heat transport adjustable" in the sense of being able to adjust the amount of heat transport to increase it.

As described above, the invention relating to the first feature can achieve "(B) making the amount of heat transport adjustable" in the sense of both increasing and decreasing the amount of heat transport by the pressure control means, without the risk of reducing the maintainability of the heat transport device by, for example, providing a drive source inside the container for moving the adjustment means back and forth.

In addition, the invention relating to the first feature can achieve "(B) making the amount of heat transport adjustable" in the sense of both increasing and decreasing heat transport by using the pressure control means, without the risk of leaking the working fluid by, for example, providing a drive source for moving the adjustment means back and forth outside the container.

Therefore, the invention relating to the first feature can achieve both objectives (A) and (B) by "(C) improving the maintainability of the heat transport device."

Therefore, according to the first aspect of the invention, in a heat transport device using thermoacoustic self-excited vibration, the following objects can be simultaneously achieved.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

The second aspect of the invention is the first aspect of the invention, in which the working fluid includes air, the pressure control means is capable of controlling the pressure to be less than a first pressure in response to a command to reduce the amount of heat transport, and the first pressure is 0.2 MPa or less.

By using air, which is easy to procure and manage, as the working fluid, the maintainability of heat transport devices can be improved.

Incidentally, it is known that the generation of self-excited vibrations in air near normal pressure is relatively weak. When such weak self-excited vibrations are generated, the thermoacoustics in the pipe are reduced by resistance caused by the viscosity of the air, etc.

In accordance with the second aspect of the invention, the working fluid contains air, and pressure control is performed to make the pressure of the working fluid less than the first pressure described above in response to a command to reduce the amount of heat transport, thereby reducing thermoacoustics within the pipe.

As a result, the invention relating to the second feature can perform control to reduce the amount of heat transport while using air, which is easy to procure and manage, as the working fluid.

Therefore, according to the second aspect of the invention, in a heat transport device using thermoacoustic self-excited vibration, the following objects can be simultaneously achieved.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

The third aspect of the invention is the first or second aspect of the invention, in which the working fluid includes air, the pressure control means is capable of controlling the pressure to be equal to or greater than a second pressure in response to a command to increase the amount of heat transport, and the second pressure is equal to or greater than 0.3 MPa.

After extensive research, the inventors have discovered that even if the working fluid is air, as long as it is at or above a certain pressure higher than normal pressure, it is possible to generate sufficiently strong self-excited vibrations that are not diminished by resistance caused by the viscosity of the air, etc.

According to the third aspect of the invention, pressure control is performed to make the pressure of the working fluid equal to or higher than the second pressure described above in response to a command to increase the amount of heat transport, so that the thermoacoustics in the pipe can be increased even though the working fluid is air.

As a result, the invention relating to the third feature can perform control to increase the amount of heat transport, even though it uses air as the working fluid, which is easy to procure and manage.

Therefore, according to the third aspect of the invention, in a heat transport device using thermoacoustic self-excited vibration, the following objects can be simultaneously achieved.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

The fourth aspect of the invention provides a furnace comprising the heat transport device of the first aspect of the invention, the heat transport device being disposed so as to straddle the interior of the furnace and the exterior of the furnace.

According to the invention relating to the fourth feature, a heat transport device having a structure suitable for transporting heat from a high-temperature heat source such as a furnace is arranged to span the inside and outside of the furnace, thereby improving the amount of heat transport in the furnace using self-excited thermoacoustic vibrations. This also makes it possible to adjust the amount of heat transport, improving maintainability.

Therefore, according to the fourth aspect of the present invention, in a heat transport device using thermoacoustic self-excited vibration, the following objects can be simultaneously achieved.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

According to the present invention, in a heat transport device using thermoacoustic self-excited vibration, the following objects can be simultaneously achieved.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

FIG. 1 is a schematic diagram showing a state in which a heat transport device 1 according to the first embodiment is attached to a furnace F. As shown in FIG. FIG. 2 is a diagram showing an example of a preferred embodiment of the first heat exchanger 12. As shown in FIG. FIG. 3 is an enlarged view of the periphery of the first heat exchanger 12 in FIG. FIG. 4 is a main flow chart showing an example of a preferable flow of the pressure control process executed by the controller of the pressure control means 15. As shown in FIG. FIG. 5 is a schematic diagram showing a state in which the heat transport device 5 of the second embodiment is attached to a furnace F. As shown in FIG. FIG. 6 is a graph showing the relationship between the length of the heat accumulator and the amount of heat transport for each temperature of the furnace F in Examples 1 to 5. FIG. 7 is a graph showing the relationship between the temperature of the furnace F and the amount of heat transport in Examples 3 and 7. FIG. 8 is a graph showing the relationship between the temperature of the furnace F and the strength of the self-excited vibration (magnitude of the pressure amplitude) in Examples 3 and 7. FIG. 9 is a graph showing the relationship between the strength of the self-excited oscillation (magnitude of pressure amplitude) and the amount of heat transport in Examples 3 and 7. FIG. 10 is a graph showing the relationship between the pressure of the working fluid and the amount of heat transport in the heat transport device 1 of Example 6, which was measured in a preliminary experiment.

Below, an example of a preferred embodiment for implementing the present invention will be described with reference to the drawings. Note that this is merely an example, and the technical scope of the present invention is not limited to this example.

First Embodiment
The heat transport device 1 of the first embodiment can be arranged to span between a high-temperature heat source and the outside of the high-temperature heat source, and can transport heat from the high-temperature heat source to the outside of the high-temperature heat source by self-excited thermoacoustic vibrations generated in the heat storage tank.

<Heat transport device 1>
1 is a schematic diagram showing a state in which a heat transport device 1 of the first embodiment is attached to a furnace F. The heat transport device 1 of the present embodiment includes a container 11 having therein a pipe 11P whose both ends can be substantially closed.

[Container 11]
The container 11 can be disposed so as to straddle between a high-temperature heat source, exemplified by a furnace F or the like, and the outside of the high-temperature heat source. Hereinafter, the high-temperature heat source is also simply referred to as "furnace F or the like."

The vessel 11 is defined by the inner wall of the vessel 11 and has a pipe 11P inside, both ends of which can be substantially closed. The inside of the pipe 11P can be filled with a working fluid, and a first heat exchanger 12, a heat accumulator 13, and a second heat exchanger 14 are arranged in this order from the first end 11E1 to the second end 11E2 of the pipe 11P.

[Material of container 11]
There is no particular limitation on the material of the container 11. Examples of the material of the container 11 include stainless steel, nickel alloy, cobalt alloy, and heat-resistant ceramic.

The material of the container 11 preferably contains stainless steel. This allows the container 11 and the heat transport device 1 to exhibit various favorable physical properties at high temperatures that are derived from stainless steel. In particular, the resistance to high-temperature corrosion that is derived from stainless steel with regard to these physical properties may enable the heat transport device 1, which transports heat from a furnace F or the like, to be operated for a long period of time.

When the temperature of the furnace F or the like can reach 550°C or higher, it is preferable that the material of the portion of the container 11 disposed at the position of the furnace F or the like contains austenitic stainless steel among stainless steels. By making the container 11 contain austenitic stainless steel, which has excellent corrosion resistance at high temperatures among stainless steels, as a material, the heat transport device 1 can be operated for an even longer period of time.

When the temperature of the furnace F or the like can reach 900°C or higher, it is preferable that the material of the portion of the container 11 disposed at the position of the furnace F or the like contains a nickel alloy and/or a cobalt alloy. Nickel alloys and cobalt alloys have physical properties that make them excellent in heat resistance. By containing a nickel alloy and/or a cobalt alloy as a material of the container 11, the heat transport device 1 can be operated for an even longer period of time.

When the temperature of the furnace F or the like can reach 900°C or higher, it is preferable that the material of the portion of the container 11 disposed at the location of the furnace F or the like contains, among nickel alloys, a nickel-chromium alloy and/or a nickel-iron-chromium alloy. These alloys have physical properties that make them highly resistant to oxidation at high temperatures. By making the container 11 contain one of these alloys as a material, the heat transport device 1 can be operated for an even longer period of time.

Examples of nickel-chromium alloys include nickel-chromium-tungsten-molybdenum alloys such as Haynes 230 alloy (registered trademark), nickel-chromium-aluminum-iron alloys such as Haynes 214 alloy (registered trademark), and nickel-cobalt-chromium-molybdenum-aluminum alloys such as Haynes 233 alloy (registered trademark). Haynes 230 alloy is also known as MA23 alloy.

Examples of nickel-iron-chromium alloys include nickel-iron-cobalt-aluminum alloys such as Haynes HR-224 alloy (registered trademark).

When the temperature of the furnace F or the like can reach 900°C or higher, it is preferable that the material of the portion of the container 11 disposed at the location of the furnace F or the like contains a cobalt-nickel alloy among cobalt alloys. Cobalt-nickel alloys have physical properties that make them highly resistant to oxidation at high temperatures. By making the container 11 contain a cobalt-nickel alloy as a material, the heat transport device 1 can be operated for an even longer period of time.

Examples of cobalt-nickel alloys include cobalt-nickel-chromium-tungsten alloys such as Haynes 25 alloy and Haynes 188 alloy (registered trademark).

[Shape of the pipe 11P]
The shape of the conduit 11P is not particularly limited. Examples of the shape of the conduit 11P include a substantially linear shape and a shape including a curved portion.

The substantially linear shape of the conduit 11P can reduce the weakening of the self-excited vibration due to the variation in phase of the thermoacoustic self-excited vibration at the curved portion. If the shape of the conduit 11P includes a curved portion, it is preferable that the curved portion does not include a portion with a sharp bend angle that may hinder the transmission of the thermoacoustic self-excited vibration.

(Pressure control means, etc. can be connected)
The shape of the conduit 11P is preferably a shape having a hole and/or a branch pipe to which the pressure control means 15 described later can be connected. This makes it possible to connect the pressure control means 15 to the conduit 11P and control the pressure of the working fluid sealed inside the conduit 11P.

The shape of the conduit 11P is preferably one that has holes and/or branch pipes to which a temperature measuring means can be connected. This makes it possible to connect a temperature measuring means to the conduit 11P and measure the temperature of the working fluid sealed inside the conduit 11P.

(Dimensions of pipe 11P)
The length of the pipe 11P is not particularly limited and can be appropriately set depending on the space in which the heat transport device 1 is disposed, etc.

The cross-sectional area of the conduit 11P is not particularly limited. The cross-sectional area of the conduit 11P can be set appropriately depending on the space in which the heat transport device 1 is placed, the amount of heat transport required for the heat transport device 1, etc.

The large cross-sectional area of the pipe 11P can further increase the volume of the working fluid that transports heat from the first heat exchanger 12 to the second heat exchanger 14 in the pipe 11P. This allows the heat transport device 1 to transport more heat. The small cross-sectional area of the pipe 11P allows the heat transport device 1 to be installed in a smaller space.

[Working fluid]
(Type of working fluid)
The working fluid is not particularly limited, and examples of the working fluid include gases including air, moist air, and inert gases.

Among them, it is preferable that the working fluid contains air. By using a working fluid containing air, which has little impact on the environment in the event of leakage and is easy to obtain, it is possible to reduce the adverse impact on the environment caused by the operation of the heat transport device 1 and the costs associated with the operation.

The working fluid may contain an inert gas, such as nitrogen, helium, neon, argon, xenon, etc. This can suppress oxidation and corrosion of the pipe 11P and the components disposed inside the pipe 11P, and can be expected to make the self-excited vibration generated by the heat accumulator 13 stronger than when air is used as the working fluid.

The working fluid may include air (humid air) that contains a substance that can move between gas and liquid phases between the temperature of the high-temperature heat source and the temperature of the heat transfer medium described below. Examples of such substances include water and ethanol. By including humid air in the working fluid, it can be expected that the self-excited vibration generated by the heat accumulator 13 will be stronger than when air is used as the working fluid.

(Working fluid pressure)
When the working fluid is air, the upper limit of the pressure of the working fluid when heat is not transported from the furnace F or the like is not particularly limited. The upper limit is, for example, preferably 0.2 MPa or less, more preferably 0.15 MPa or less, and even more preferably 0.13 MPa or less. Hereinafter, the upper limit of the pressure of the working fluid when heat is not transported from the furnace F or the like is also simply referred to as the "first pressure."

It is known that the generation of self-excited vibrations in air near normal pressure is relatively weak. When such weak self-excited vibrations are generated, the thermoacoustics in the pipe are reduced by resistance caused by the viscosity of the air, etc.

By determining the lower limit of the working fluid pressure when heat is not being transported from the furnace F, etc., as described above, it is possible to substantially stop the thermoacoustics in the pipe.

When the working fluid is air, there is no particular limitation on the lower limit of the pressure of the working fluid when transporting heat from a furnace F or the like. The lower limit is, for example, preferably 0.3 MPa or more, more preferably 0.4 MPa or more, and even more preferably 0.5 MPa or more. Hereinafter, the lower limit of the pressure of the working fluid when transporting heat from a furnace F or the like is also simply referred to as the "second pressure."

By setting the lower limit of the working fluid pressure when transporting heat from a furnace F, etc., as described above, it is possible to increase the thermoacoustics in the pipe, even though the working fluid is air.

If the working fluid is air, the upper limit of the working fluid pressure when transporting heat from a furnace F, etc. is preferably 2 MPa or less, more preferably 1.5 MPa or less, and even more preferably 1 MPa or less.

By setting the upper limit of the working fluid pressure when transporting heat from a furnace F, etc., as described above, the risk of accidents caused by leakage of the working fluid can be reduced. In addition, by setting the upper limit of the working fluid pressure when transporting heat from a furnace F, etc., as described above, a decrease in the amount of heat transport due to excessively high pressure can be prevented.

[First heat exchanger 12]
The first heat exchanger 12 is disposed at a position where it can transfer heat from the furnace F, etc., to the working fluid. The first heat exchanger 12 is not particularly limited as long as it can obtain heat from the furnace F, etc., that the vessel 11 has obtained by radiation from the pipe 11P, thermal conduction from the vessel 11 to the first heat exchanger 12, etc., and can transfer the received heat to the working fluid by thermal conduction, etc.

The first heat exchanger 12 may be constructed separately from the container 11, or may be constructed substantially integrally with the container 11. Here, when a certain member is "constructed substantially integrally with the container 11," this means that when the heat transport device 1 transports heat from a furnace F or the like, the member defines a pipeline 11P integrally with the container 11 or the like.

[Location of first heat exchanger 12]
The position where the first heat exchanger 12 is disposed is not particularly limited as long as the first heat exchanger 12, the heat accumulator 13, and the second heat exchanger 14 are disposed in order from the first end 11E1 to the second end 11E2 of the pipe 11P and the heat of the furnace F or the like can be transferred to the working fluid. For example, when the heat transport device 1 is disposed so as to straddle between the furnace F or the like and the outside of the furnace F or the like, the position of the pipe 11P corresponding to the part of the container 11 that is the periphery of the furnace F or the like (FIG. 1).

The location where the first heat exchanger 12 is disposed is preferably near the heat accumulator 13. This allows the first heat exchanger 12 to increase the temperature of the working fluid around one end of the heat accumulator 13 more than if the location was not near the heat accumulator 13.

The upper limit of the distance between the end of the first heat exchanger 12 closest to the heat accumulator 13 and the end of the heat accumulator 13 closest to the first heat exchanger 12 is preferably 1/40 or less of the length of the pipe 11P, more preferably 1/70 or less of the length of the pipe 11P, and even more preferably 1/100 or less of the length of the pipe 11P. This allows the first heat exchanger 12 to further increase the temperature of the working fluid around one end of the heat accumulator 13.

[Dimensions of first heat exchanger 12]
The length of the first heat exchanger 12 in the direction along the pipe 11P is not particularly limited. The lower limit of the length is preferably 2/100 or more of the length of the pipe 11P, and more preferably 3/100 or more of the length of the pipe 11P. This allows the first heat exchanger 12 to further increase the temperature of the working fluid around one end of the heat accumulator 13.

The upper limit of the length of the first heat exchanger 12 in the direction along the pipe 11P is preferably 30/100 or less of the length of the pipe 11P, and even more preferably 25/100 or less of the length of the pipe 11P. This can reduce various unexpected effects of the first heat exchanger 12 on the thermoacoustic self-excited vibration.

[Plate heat exchanger]
The first heat exchanger 12 may be, for example, a plate-type heat exchanger having a plurality of substantially plate-shaped heat receiving parts, one of whose directions along the surface of the heat receiving parts substantially coincides with the direction along the pipe 11P. The first heat exchanger 12, which is a plate-type heat exchanger, is configured by arranging substantially plate-shaped heat receiving parts (plates) in parallel. In this case, it is preferable that one of the directions along the surface of the plate substantially coincides with the direction along the pipe 11P. This can reduce the blocking of the self-excited vibration of thermoacoustics propagating through the working fluid by the plate.

The first heat exchanger 12, which is a plate-type heat exchanger, can increase the cross-sectional area of the connection between the heat receiving part and the container 11. This is expected to promote active heat transfer by thermal conduction from the container 11 to the heat receiving part. In addition, the first heat exchanger 12, which is a plate-type heat exchanger, can increase the surface area of the heat receiving part relative to the number of heat receiving parts. This is expected to promote active heat transfer by thermal conduction from the heat receiving part to the working fluid.

The material of the plate heat exchanger may be the same as the material of the container 11 described above. The effects of the material of the plate heat exchanger are the same as those described for the material of the container 11 described above.

[Pin type heat exchanger]
An example of the first heat exchanger 12 is a pin-type heat exchanger having a plurality of rod-shaped heat receiving parts whose longitudinal direction is substantially aligned with the direction along the pipe 11P. Fig. 2 is a diagram showing an example of a preferred embodiment of the first heat exchanger 12. Hereinafter, an example of a preferred embodiment in which the first heat exchanger 12 of the present embodiment is configured as a pin-type heat exchanger will be described with reference to Fig. 2.

The first heat exchanger 12, which is a pin-type heat exchanger, is disposed on a base and has multiple rod-shaped heat receiving portions 12a whose longitudinal direction is approximately aligned with the direction along the pipeline 11P (the direction of the arrow in FIG. 2). The base may be configured as a plate-shaped member, or may be configured integrally with the first end portion 11E1 of the pipeline 11P. Hereinafter, the first heat exchanger 12, which is a pin-type heat exchanger, is also referred to simply as a "pin-type heat exchanger."

When the heat transport device 1 is disposed so as to span between the furnace F etc. and the outside of the furnace F etc., the heat of the furnace F etc. first moves to the container 11. The heat that has moved to the container 11 then moves to the first heat exchanger 12 via radiation and thermal conduction. The heat that has moved to the first heat exchanger 12 then moves to the working fluid via thermal conduction.

Incidentally, between two objects with different temperatures, the amount of heat transfer due to thermal conduction is proportional to the difference in their absolute temperatures. On the other hand, the amount of heat transfer due to radiation is proportional to the difference in the fourth power of the absolute temperatures. Therefore, at high temperatures where the absolute temperature is high, the amount of heat transfer due to radiation is expected to be greater than the amount of heat transfer due to thermal conduction.

However, when the first heat exchanger 12 is constructed using a plate heat exchanger, there is a concern that plates that are blocked from the inner wall of the container by other plates may not be able to receive sufficient radiation. Therefore, there may be room for further improvement in the plate heat exchanger in terms of transferring heat from a furnace F or the like, which has a high absolute temperature, to the first heat exchanger 12 by radiation.

The pin-type heat exchanger has multiple rod-shaped heat receiving parts 12a whose longitudinal direction is approximately aligned with the direction along the pipe. This allows the heat receiving parts 12a to receive heat radiation from the container 11 without blocking the radiation from the container 11. This can enhance the transfer of heat from the container 11 to the first heat exchanger 12. Therefore, the pin-type heat exchanger can transfer even more heat from the furnace F, etc. to the working fluid.

By transferring more heat from the furnace F etc. to the working fluid, the pin-type heat exchanger can further increase the temperature gradient in the heat accumulator. Typically, as the temperature gradient in the heat accumulator increases, the self-excited vibration that is generated becomes stronger. Thus, the pin-type heat exchanger can improve the amount of heat transport in heat transport using self-excited vibration.

The material of the pin-type heat exchanger may be the same as the material of the container 11 described above. The effects of the material of the pin-type heat exchanger are the same as those described for the material of the container 11 described above.

(Regarding the formation of the base part integral with the first end part 11E1 of the pipe 11P)
Fig. 3 is an enlarged view of the periphery of the first heat exchanger 12 in Fig. 1. An example of a more preferable embodiment in which the first heat exchanger 12 of the present embodiment is configured as a pin-type heat exchanger will be described with reference to Fig. 3.

When the first heat exchanger 12 of this embodiment is configured as a pin-type heat exchanger, it is preferable that the base portion be configured integrally with the first end portion 11E1 of the pipe 11P.

The heat transport device 1 of this embodiment transports heat from a furnace F or the like by thermoacoustic self-excited vibration in the working fluid. Incidentally, the self-excited vibration has the properties of a sound wave with the working fluid as a medium. Therefore, if there is a structure inside the pipe 11P that obstructs the sound waves, the thermoacoustic self-excited vibration may be obstructed. This may prevent the generation of stronger self-excited vibration.

By forming the base part integrally with the first end 11E1 of the pipe 11P, the base part formed separately within the pipe 11P can be prevented from interfering with the sound waves. This can further reduce the base part's inhibition of the thermoacoustic self-excited vibration.

In addition, in this configuration, the heat receiving portion 12a can be configured with a length equal to or less than the distance from the first end 11E1 to the heat storage device 13, so the surface area of the heat receiving portion 12a can be increased. This allows the heat receiving portion 12a to receive more heat and transfer it to the working fluid. This can further increase the heat transport capacity of the heat transport device 1.

The longitudinal length of the heat receiving portion 12a in the pin-type heat exchanger is not particularly limited. Examples of the longitudinal length of the heat receiving portion 12a include a length that is approximately the same as the length along the direction of the pipe 11P of the pin-type heat exchanger, a length that makes the heat receiving portion 12a arranged closer to the pipe 11P shorter, etc.

The thickness of the heat receiving portion 12a in the pin-type heat exchanger is not particularly limited. The lower limit of the thickness of the heat receiving portion 12a is preferably 1 mm or more, more preferably 1.5 mm or more, and even more preferably 1.8 mm or more. This can reduce deformation of the heat receiving portion 12a due to thermoacoustic self-excited vibrations, etc.

The upper limit of the thickness of the heat receiving portion 12a is preferably 6 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. This increases the surface area of each heat receiving portion 12a. This further promotes the transfer of heat by heat transfer between the heat receiving portion 12a and the working fluid.

The spacing of the heat receiving parts 12a in the pin-type heat exchanger is not particularly limited. It is more preferable that the lower limit of the spacing of the heat receiving parts 12a is equal to or greater than the thickness of the thermal boundary layer in the working fluid sealed in the pipe 11P. This can further reduce the heat receiving parts 12a from impeding the thermoacoustic self-excited vibration.

The upper limit of the spacing between the heat receiving parts 12a is preferably no more than twice the width of the heat receiving parts 12a, and even more preferably no more than 3/2 times the width of the heat receiving parts 12a. This allows more heat receiving parts 12a to be provided on the base, increasing the amount of heat transferred from the entire heat receiving parts 12a to the working fluid. This also reduces the amount of radiant heat from the inside of the pipe 11P that is not received by the heat receiving parts 12a.

[Heat accumulator 13]
Returning to Fig. 1, the heat accumulator 13 is a member capable of generating thermoacoustic self-excited vibration in response to a temperature gradient. The shape of the heat accumulator 13 is substantially columnar. The heat accumulator 13 includes a gap communicating between both bottom surfaces.

The heat accumulator 13 has a generally cylindrical shape, which makes it easy to place the heat accumulator 13 inside the pipe 11P. The heat accumulator 13 has a generally cylindrical shape, which makes it possible for the heat accumulator 13 to generate thermoacoustic self-excited vibrations at both planar ends in a direction along the pipe 11P.

When the heat storage device 13 is disposed in the pipe 11P of the heat transport device 1, the above-mentioned gap can connect the periphery of the high temperature part in the pipe 11P to the periphery of the low temperature part in the pipe 11P. Here, the high temperature part is the high temperature part brought about by the heat transferred from the furnace F or the like to the first heat exchanger 12. Therefore, the periphery of the high temperature part is, for example, the periphery of the first heat exchanger 12. Also, here, the low temperature part is the low temperature part brought about by the transfer of heat in the second heat exchanger 14. Therefore, the periphery of the low temperature part is, for example, the periphery of the second heat exchanger 14.

When the heat storage device 13 is disposed within the pipe 11P of the heat transport device 1, the heat storage device 13 includes a gap that can connect the periphery of the high-temperature portion of the pipe 11P with the periphery of the low-temperature portion of the pipe 11P. As a result, when the heat storage device 13 is disposed within the pipe 11P, it is possible to generate thermoacoustic self-excited vibrations in response to the temperature gradient that occurs inside the heat storage device 13 due to the temperature difference between the high-temperature portion and the low-temperature portion.

The heat storage device 13 may be configured separately from the container 11, or may be configured substantially integrally with the container 11.

[Gap flow path radius]
It is preferable that the flow passage radius r [m] of the gap satisfies the relationship of the following formula (1) with respect to the thickness δ [m] of the thermal boundary layer of the working fluid related to the self-excited thermoacoustic oscillation generated in the heat accumulator 13. More specifically, it is preferable that (r/δ) ² is in the range of 0.1 to 10.

The following is an explanation of the above relationship based on Non-Patent Document 1. The thickness δ [m] of the thermal boundary layer of the working fluid is given by the following formula (2), where the thermal diffusivity of the working fluid is α [m ² /s] and the angular frequency of the self-excited vibration is ω [Hz].

The heat exchange occurring in the gap of the heat accumulator 13 is determined by a dimensionless quantity ωτ defined as the product of the thermal relaxation time τ [s] and the angular frequency ω [Hz] of the working fluid, which is the medium of the thermoacoustic vibration. Here, the thermal relaxation time τ [s] is given by the following equation (3).

When the value of ωτ is close to 1, the heat exchange between the solid walls that form the flow path and the working fluid becomes insufficient, and a time lag (phase lag) occurs in the net heat exchange process within the cross section of the flow path. This can generate self-excited thermoacoustic oscillations.

By combining and transforming the above-mentioned formula (2) and formula (3), the following formula (4) is obtained. Therefore, if the relationship between the flow path radius r [m] and the thermal boundary layer thickness δ [m] satisfies the condition of formula (1), thermoacoustic self-excited vibration can be generated in the heat accumulator 13.

[Length of heat accumulator 13 along pipe 11P]
The lower limit of the length of the heat storage unit 13 along the pipe 11P is preferably 9% or more of the length of the pipe 11P (pipe length), and more preferably 13% or more of the pipe length.

The inventors have found that there are cases where the results of numerical calculations regarding thermoacoustic self-excited vibrations differ from the measured values in an actual device. After extensive investigation, the inventors have found that the above-mentioned differences may be caused by the difference between the actual device and the numerical calculations, that is, part of the heat storage device in the actual device also functions as a heat exchanger.

In a heat transport device 1 applied to a high-temperature furnace, the means for transferring heat from the furnace to the working fluid is more important than in a thermoacoustic device that operates at low temperatures near or below room temperature. If the lower limit of the length of the heat storage device 13 along the pipe 11P is equal to or greater than the above-mentioned threshold, the portion of the heat storage device 13 that functions as a heat exchanger can be made larger.

Therefore, the heat accumulator 13 whose lower limit of the length along the pipe 11P is equal to or greater than the above-mentioned threshold value can function as an additional means for transferring heat from the furnace to the working fluid. In other words, the heat accumulator 13 whose lower limit of the length along the pipe 11P is equal to or greater than the above-mentioned threshold value can contribute to further transporting heat from the furnace F, etc.

[Material of heat accumulator 13]
There is no particular limitation on the material of the heat accumulator 13. For example, the material of the heat accumulator 13 includes one or more of a metal material such as stainless steel, an inorganic material such as ceramic, an anisotropic thermally conductive material such as a graphite sheet, and the like.

In terms of the material of the heat storage unit 13, the heat transport device 1, which transports heat from the furnace F etc. to the outside of the furnace F etc., requires the heat storage unit 13 to be heat resistant.

If the material of the heat storage device 13 contains an inorganic material, the heat storage device 13 can be configured as a porous body formed by sintering an inorganic material such as a ceramic honeycomb. This makes it possible to realize a heat storage device 13 with excellent heat resistance and corrosion resistance at high temperatures.

Regarding the material of the heat storage device 13, in a heat transport device using self-excited vibration, the greater the temperature gradient inside the heat storage device, the stronger the self-excited vibration of the generated thermoacoustic sound. Also, in a heat transport device using self-excited vibration, the easier the heat transfer between the heat storage device and the working fluid, the stronger the self-excited vibration of the generated thermoacoustic sound.

However, while lowering the thermal conductivity of the heat accumulator 13 is effective in reducing the loss of the temperature gradient inside the heat accumulator 13, increasing the thermal conductivity of the heat accumulator 13 is effective in facilitating heat transfer between the heat accumulator 13 and the working fluid. Therefore, it is not easy to achieve both of these conditions and strengthen the self-excited vibration of the generated thermoacoustics.

If the material of the heat storage device 13 includes a metal material, the heat storage device 13 can be configured, for example, as a metal mesh laminate in which thin plate-shaped meshes formed using a metal material are stacked.

As a result, the heat storage device 13 can achieve high thermal conductivity in the direction along the surface of the mesh. In other words, it is possible to facilitate heat transfer between the heat storage device 13, which is configured as a metal mesh laminate, and the working fluid.

In addition, this allows the heat storage device 13 to reduce the contact area between the meshes in the overlapping direction of the meshes. In other words, the heat storage device 13 configured as a metal mesh laminate can reduce the elimination of the temperature gradient inside the heat storage device 13 by roughly aligning the overlapping direction of the meshes with the direction of the temperature gradient.

Therefore, the heat storage device 13 configured as a metal mesh laminate can simultaneously suppress the thermal conductivity in the direction of the temperature gradient to be low, thereby preventing the thermal conduction in the heat storage device 13 from eliminating the temperature gradient, and facilitate the transfer of heat between the heat storage device 13 and the working fluid by realizing high thermal conductivity in a direction different from the direction of the temperature gradient.

The material of the heat storage device 13 preferably contains a thermally anisotropic material. By including a thermally anisotropic material in the material of the heat storage device 13, the heat storage device 13 can be configured so that the direction in which the thermal conductivity of the thermally anisotropic material is low is substantially the same as the direction along the pipe 11P.

Incidentally, thermally conductive anisotropic materials such as graphite sheets are known that are configured so that the thermal conductivity in the plane direction is 100 times or more that in the thickness direction. In this way, thermally conductive anisotropic materials can be configured so that the thermal conductivity differs greatly between the direction in which the thermal conductivity is low and the direction in which the thermal conductivity is high.

Due to the characteristics of the thermally conductive anisotropic material described above, the heat storage device 13 is configured so that the direction in which the thermal conductivity of the thermally conductive anisotropic material is low is substantially the same as the direction along the pipe 11P. This makes it possible to simultaneously suppress the thermal conductivity in the direction of the temperature gradient to be lower than that of the metal mesh laminate, thereby preventing the thermal conduction in the heat storage device 13 from eliminating the temperature gradient, to realize high thermal conductivity in a direction different from the direction of the temperature gradient, thereby facilitating heat transfer between the heat storage device 13 and the working fluid, and to realize a heat storage device 13 with high heat resistance.

The thermally conductive anisotropic material is not particularly limited, but preferably includes the above-mentioned graphite sheet. This makes it possible to utilize the excellent properties of the graphite sheet, which, among thermally conductive anisotropic materials, can make the thermal conductivity in the surface direction 100 times or more higher than in the thickness direction.

If the thermally conductive anisotropic material can be formed into a plate shape, and when formed into a plate shape, the thermal conductivity of the material is higher in the planar direction than in the thickness direction, the heat storage device 13 is preferably configured as a thermally conductive anisotropic material laminate in which plate-shaped bodies of the thermally conductive anisotropic material are stacked, with holes provided corresponding to the voids. An example of such a thermally conductive anisotropic material laminate is a graphite sheet laminate. This makes it possible to obtain a heat storage device 13 in which the direction in which the thermal conductivity of the thermally conductive anisotropic material is low is approximately the same as the direction along the pipe 11P, and which has voids formed by the holes provided in each of the stacked thin plates.

If the thermally conductive anisotropic material can be formed into a film, and when formed into a film, the thermal conductivity in any direction along the surface direction is lower than in the thickness direction, it is preferable that the heat storage device 13 is constructed by rolling the film of the thermally conductive anisotropic material so that the direction in which the thermal conductivity is low faces the pipe 11P. This makes it possible to obtain a heat storage device 13 in which the direction in which the thermal conductivity of the thermally conductive anisotropic material is low is approximately the same as the direction along the pipe 11P, and in which a gap is formed between the rolled films.

[Location of heat accumulator 13]
The position at which the heat storage device 13 is disposed is such that the first heat exchanger 12, the heat storage device 13, and the second heat exchanger 14 are disposed in order from the first end 11E1 of the pipeline 11P toward the second end 11E2, and it is preferable that the heat storage device relative position, which is the ratio of the distance along the pipeline 11P from the first end 11E1 of the pipeline 11P to the center of the heat storage device 13 divided by the length of the pipeline 11P, is a position that satisfies the conditions described below.

In a thermoacoustic engine that uses thermoacoustic self-excited vibrations as energy, it is known that the thermal efficiency of generating thermoacoustic self-excited vibrations increases when the heat accumulator relative position is 1/4 to 1/3. However, unlike the requirement for thermal efficiency in generating self-excited vibrations in a thermoacoustic engine, a heat transport device that uses thermoacoustic self-excited vibrations for heat transport requires the generation of self-excited vibrations that perform heat transport favorably.

After extensive research, the inventors discovered that self-excited vibrations that optimally transport heat can be generated when the relative position of the heat storage unit satisfies the following conditions.

The lower limit of the heat storage unit relative position is preferably 2/25 or more, and even more preferably 4/25 or more. The upper limit of the heat storage unit relative position is preferably 9/25 or less, and even more preferably 8/25 or less.

[Second heat exchanger 14]
The second heat exchanger 14 is capable of transferring heat of the working fluid to an external heat medium such as a furnace F. The second heat exchanger 14 and the heat medium are not particularly limited.

The second heat exchanger 14 may be configured separately from the container 11, or may be configured substantially integrally with the container 11.

[Type of second heat exchanger 14]
The second heat exchanger 14 is preferably a gas-liquid heat exchanger that uses a liquid as a heat medium. In this way, the second heat exchanger 14 can transfer the heat of the working fluid to an external heat medium such as a furnace F by using a liquid having a larger specific heat than a gas.

The liquid heat transfer medium is preferably composed mainly of water. A heat transfer medium composed mainly of water can utilize the high specific heat of water as a heat transfer medium and can prevent the heat transfer medium from having undesirable effects on the environment. This can also make it easier to procure the heat transfer medium.

The type of the second heat exchanger 14, which is a gas-liquid heat exchanger, is not particularly limited. Examples of such types include a shell-and-tube type gas-liquid heat exchanger, a fin-tube type gas-liquid heat exchanger, a flat tube finless type gas-liquid heat exchanger, a coil type gas-liquid heat exchanger, etc.

The second heat exchanger 14, which is a gas-liquid heat exchanger, is preferably a shell-and-tube gas-liquid heat exchanger configured such that a tube through which a working fluid can pass passes along the direction of the pipe 11P inside a shell capable of flowing a heat medium. The second heat exchanger 14, which is a shell-and-tube gas-liquid heat exchanger, can simultaneously reduce pressure loss in the working fluid and increase the efficiency of transferring heat from the working fluid to an external heat medium such as a furnace F.

[Dimensions of second heat exchanger 14]
The length of the second heat exchanger 14 in the direction along the pipe 11P is not particularly limited. The lower limit of the length is preferably 1/100 or more of the length of the pipe 11P, more preferably 2/100 or more of the length of the pipe 11P, and even more preferably 3/100 or more of the length of the pipe 11P. This allows the second heat exchanger 14 to transfer heat from the working fluid present around one end of the heat accumulator 13 even more effectively.

The upper limit of the length is preferably 10/100 or less of the length of the pipe 11P, and even more preferably 8/100 or less of the length of the pipe 11P. This can reduce the influence of the second heat exchanger 14 on the thermoacoustic self-excited vibration.

[Location of second heat exchanger 14]
The position of the second heat exchanger 14 is not particularly limited as long as the first heat exchanger 12, the heat accumulator 13, and the second heat exchanger 14 are arranged in order from the first end 11E1 to the second end 11E2 of the pipe 11P and the heat of the working fluid can be transferred to a heat medium outside the furnace F. For example, when the heat transport device 1 is arranged to straddle between the furnace F and the outside of the furnace F, the position of the pipe 11P corresponding to a portion of the container 11 that is in the vicinity of the outside of the furnace F (FIG. 1).

The second heat exchanger 14 is preferably disposed near the heat accumulator 13. This allows the second heat exchanger 14 to lower the temperature of the working fluid around one end of the heat accumulator 13 compared to when the position is not near the heat accumulator 13.

The upper limit of the distance between the end of the second heat exchanger 14 closest to the heat accumulator 13 and the end of the heat accumulator 13 closest to the second heat exchanger 14 is preferably 1/40 or less of the length of the pipe 11P, more preferably 1/70 or less of the length of the pipe 11P, and even more preferably 1/100 or less of the length of the pipe 11P. This allows the second heat exchanger 14 to further lower the temperature of the working fluid around one end of the heat accumulator 13.

[Pressure control means 15]
The heat transport device 1 preferably includes a pressure control means 15 capable of controlling the pressure of the working fluid sealed inside the pipe 11P. The pressure control means 15 includes at least a pressurizing means capable of increasing the pressure of the working fluid, and a depressurizing means capable of decreasing the pressure of the working fluid. The pressurizing means and the depressurizing means may be connected to the inside of the pipe 11P via a common valve, or may be connected to the inside of the pipe 11P via a plurality of valves including a valve corresponding to the pressurizing means and a valve corresponding to the depressurizing means.

[Pressure means]
The pressurizing means is not particularly limited. For example, a compressor that can be connected to the pipe 11P can be used as the pressurizing means. By including the pressurizing means, the pressure control means 15 can control the pressure of the working fluid to be increased so that the heat accumulator 13 strengthens the self-excited vibration in response to a command to increase the amount of heat transport.

It is known that the generation of thermoacoustic self-excited oscillations in the heat accumulator 13 is affected by the pressure of the working fluid. However, the generation of self-excited oscillations in air near normal pressure is relatively weak. When such weak self-excited oscillations are generated, the thermoacoustics in the pipe are reduced by resistance caused by the viscosity of the air, etc.

Since the pressure control means 15 includes a pressurizing means, the pressure of the working fluid can be increased from normal pressure or a pressure equal to or lower than the first pressure described above to a pressure equal to or higher than the second pressure described above. This allows the heat accumulator 13 to generate or intensify thermoacoustic self-excited oscillations even if the working fluid is air. Using this thermoacoustic self-excited oscillation, the heat transport device 1 can transport heat from the furnace F, etc. to the outside of the furnace F, etc.

Therefore, the pressure control means 15 can achieve "(A) improvement in the amount of heat transport in heat transport using self-excited vibration" by increasing the pressure of the working fluid to the above-mentioned second pressure or higher using the pressurizing means.

[Pressure reduction means]
The pressure reducing means is not particularly limited. The pressure reducing means is not particularly limited. For example, an exhaust valve connectable to the pipe 11P can be cited as an example of the pressure reducing means. By including the pressure reducing means, the pressure control means 15 can perform control to reduce the pressure of the working fluid so that the heat accumulator 13 weakens or substantially stops the self-excited vibration in response to a command to increase the heat transport amount.

Since the pressure control means 15 includes a pressure reducing means, the pressure of the working fluid can be reduced from a pressure equal to or higher than the second pressure described above to a pressure equal to or lower than the first pressure described above. This allows the heat accumulator 13 to weaken and essentially stop the generation of thermoacoustic self-excited oscillations when the working fluid is air. Since the thermoacoustic self-excited oscillations stop, the heat transport device 1 can stop the transport of heat from the furnace F, etc. to the outside of the furnace F, etc.

[Effect of pressure control means 15]
Since the pressure control means 15 is composed of a pressurizing means and a depressurizing means, the heat transport device 1 can realize "(B) making the heat transport amount adjustable" in the sense of both increasing and decreasing the heat transport amount by the pressure control means 15, without the risk of reducing the maintainability of the heat transport device 1 by, for example, providing a driving source for moving the pressure adjustment means back and forth inside the container 11 as in Patent Document 1.

In addition, the heat transport device 1 can achieve "(B) the ability to adjust the amount of heat transport" in the sense of both increasing and decreasing heat transport by using the pressure control means 15, without the risk of leaking the working fluid by providing a drive source for moving the pressure adjustment means back and forth outside the container as in Patent Document 1.

Therefore, the heat transport device 1 equipped with the pressure control means 15, which is configured including a pressurizing means and a depressurizing means, can achieve both "(A) improving the amount of heat transport in heat transport using self-excited vibration" and "(B) making the amount of heat transport adjustable."

[controller]
The pressure control means 15 is preferably configured to include a controller capable of controlling the pressurizing means and the depressurizing means. The controller has, as software components, a first pressure control unit capable of controlling the pressure of the working fluid so that the heat accumulator 13 weakens the self-excited oscillation in response to a command to reduce the heat transport amount of the heat transport, and a second pressure control unit capable of controlling the pressure of the working fluid so that the heat accumulator 13 strengthens the self-excited oscillation in response to a command to increase the heat transport amount of the heat transport.

As a result, the pressure control means 15 can perform pressure control to weaken the self-excited vibration in response to a command to reduce the amount of heat transport, and pressure control of the working fluid to strengthen the self-excited vibration in response to a command to increase the amount of heat transport.

The hardware configuration of the controller is not particularly limited. Examples of the hardware configuration of the controller include electronic circuits, integrated circuits, various processors, various terminals, various servers, etc.

If the controller is a processor, terminal, server, etc. that operates according to a program, the controller can read from an appropriate storage device a program capable of executing the pressure control process described below.

Preferably, the pressure control means 15 includes a pressure sensor capable of acquiring the pressure of the working fluid sealed in the pipe 11P. This allows the user of the heat transport device 1 to pressurize and/or depressurize the working fluid while referring to the pressure of the working fluid.

It is preferable that the pressure sensor is capable of providing the acquired pressure to the controller described above. This allows the controller to control the pressure of the working fluid by referring to the pressure acquired by the pressure sensor.

The pressure control means 15 preferably includes a temperature sensor capable of acquiring the temperature of the furnace F, etc. This allows the controller to control the pressure of the working fluid so that the temperature of the furnace F, etc. changes over time as desired.

Preferably, the pressure control means 15 is capable of acquiring the amount of heat transport of the heat transport device 1. This allows the controller to control the pressure of the working fluid so that the amount of heat transport is the desired amount.

[Pressure control process flow]
4 is a main flow chart showing an example of a preferred flow of the pressure control process executed by the controller of the pressure control means 15. Hereinafter, an example of a preferred flow of the pressure control process executed by the controller of the pressure control means 15 will be described with reference to FIG.

The controller first executes the first pressure control steps from step S1 to step S3.

(Step S1: Determine whether a command to reduce the amount of heat transport has been received)
The controller executes the first pressure control unit and performs a process of determining whether a command to reduce the amount of heat transport has been received (step S1, first command receiving step). If it is determined that the command has been received, the controller proceeds to step S2. If it is not determined that the command has been received, the controller proceeds to step S4.

Although not essential, it is preferable that the pressure control process includes a first pressure determination step in step S2. This allows the pressure control process to more reliably keep the pressure of the working fluid below the first pressure.

(Step S2: Determine whether the pressure of the working fluid exceeds the first pressure)
The controller executes the first pressure control unit in cooperation with the pressure sensor and performs a process of determining whether the pressure of the working fluid exceeds the first pressure (step S2, first pressure determination step). If it is determined that the signal has been received, the controller proceeds to step S3. If it is not determined that the signal has been received, the controller proceeds to step S4.

(Step S3: Decrease the pressure of the working fluid)
The controller executes the first pressure control section in cooperation with the pressure reducing means to reduce the pressure of the working fluid (step S3, pressure reducing step).The controller shifts the process to step S2.

(Step S4: Determine whether a command to increase the amount of heat transport has been received)
The controller executes the second pressure control section and performs a process of determining whether a command to increase the heat transport amount has been received (step S4, second command receiving step). If it is determined that the command has been received, the controller proceeds to step S5. If it is not determined that the command has been received, the controller proceeds to step S6.

Although not essential, it is preferable that the pressure control process includes a second pressure determination step in step S5. This allows the pressure control process to more reliably achieve the pressure of the working fluid being equal to or higher than the second pressure.

(Step S5: Determine whether the pressure of the working fluid is lower than the second pressure)
The controller executes the second pressure control section in cooperation with the pressure sensor and performs a process of determining whether the pressure of the working fluid falls below the second pressure (step S5, second pressure determination step). If it is determined that the signal has been received, the controller proceeds to step S6. If it is not determined that the signal has been received, the controller proceeds to step S1 and repeats the processes from step S1 to step S6.

(Step S6: Increase the pressure of the working fluid)
The controller executes the second pressure control section in cooperation with the pressurizing means to increase the pressure of the working fluid (step S6, pressurizing step).The controller shifts the process to step S5.

(Controlling the temperature change of the furnace F, etc. to the desired change)
When the pressure control means 15 is configured to include a temperature sensor, it is preferable that the controller can further execute the following processes: receiving a desired change in temperature measured by a temperature sensor provided in the furnace F, etc.; issuing a command to reduce the amount of heat transport when the temperature of the furnace F, etc. is lower than the temperature in the desired change; and issuing a command to increase the amount of heat transport when the temperature of the furnace F, etc. is higher than the temperature in the desired change. This allows the pressure control means 15 to realize control to make the temperature change of the furnace F, etc. the change desired by the user.

(Controlling heat transport amount to a desired range)
When the pressure control means 15 can acquire the heat transport amount of the heat transport device 1, the controller can preferably further execute the following processes: receiving a desired range for the heat transport amount, issuing a command to reduce the heat transport amount when the acquired heat transport amount exceeds the desired range, and issuing a command to increase the heat transport amount when the acquired heat transport amount falls below the desired range. This allows the pressure control means 15 to realize control to set the heat transport amount within the range desired by the user.

(Effect of pressure control process)
It is known that the generation of self-oscillations in air near normal pressure is relatively weak. When such weak self-oscillations are generated, the thermoacoustic waves in the pipe are reduced by resistance caused by the viscosity of the air, etc.

Therefore, when the working fluid contains air, the pressure control means 15 performs a pressure control process to reduce the pressure of the working fluid to less than the first pressure described above in response to a command to reduce the amount of heat transport, thereby reducing the thermoacoustics in the pipe 11P.

The pressure control means 15 performs pressure control processing to increase the pressure of the working fluid to the second pressure or higher in response to a command to increase the amount of heat transport, so that the thermoacoustics in the pipe 11P can be increased even though the working fluid is air.

Therefore, by being able to execute the above-mentioned pressure control process, the pressure control means 15 is capable of pressure control such that the heat accumulator 13 weakens the self-excited vibration in response to a command to reduce the amount of heat transport. Also, by being able to execute the above-mentioned pressure control process, the pressure control means 15 is capable of pressure control such that the heat accumulator 13 strengthens the self-excited vibration in response to a command to increase the amount of heat transport.

As a result, the pressure control means 15 can simultaneously "(A) improve the amount of heat transport in heat transport using self-excited vibration" and "(B) make the amount of heat transport adjustable."

The pressure control means 15 described above can "(B) make the amount of heat transport adjustable" in the sense of both increasing and decreasing the amount of heat transport, without the risk of reducing the maintainability of the heat transport device 1 by, for example, providing a drive source for moving the pressure adjustment means back and forth inside the container 11 as in Patent Document 1.

In addition, the pressure control means 15 described above can "adjust the amount of heat transport" (B) in the sense of both increasing and decreasing the amount of heat transport, without the risk of leaking the working fluid, such as by providing a drive source for moving the pressure adjustment means back and forth outside the container 11 as in Patent Document 1.

Therefore, the pressure control means 15 capable of executing the above-mentioned pressure control process can achieve the following objectives in the heat transport device 1 using thermoacoustic self-excited vibration.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

[High temperature heat source]
The high-temperature heat source is not particularly limited. Examples of the high-temperature heat source include various heating furnaces exemplified by the furnace F, high-temperature exhaust gas discharged through an exhaust pipe, and a member capable of receiving solar heat.

It is preferable that the high-temperature heat source can reach 600°C or higher. This allows the heat transport device 1 to transport heat from the high-temperature heat source to the outside of the high-temperature heat source, even when pressurized air is used as the working fluid.

The high-temperature heat source is preferably capable of reaching 800°C or higher. This allows the heat transport device 1 to transport heat from the high-temperature heat source to the outside of the high-temperature heat source even when pressurized air is used as the working fluid and the pressure of the air is relatively low, at 1 MPa or less.

<<Second embodiment>>
The heat transport device 1 of the first embodiment is configured to be able to be arranged so as to straddle between a high-temperature heat source and the outside of the high-temperature heat source, and a heat accumulator is arranged only at one end of the container, whereas the heat transport device 5 of the second embodiment is configured to be able to be arranged so as to extend from the high-temperature heat source to the high-temperature heat source via the outside of the high-temperature heat source, and is provided with a heat accumulator with a temperature gradient at both ends of the container, and a group of heat exchangers corresponding to each of the heat accumulators.

<Heat Transport Device 5>
5 is a schematic diagram showing a state in which the heat transport device 5 of the second embodiment is attached to a furnace F. The heat transport device 5 of this embodiment includes a container 51 having therein a pipe 51P whose both ends can be substantially closed.

[Container 51]
Unlike the container 11 of the first embodiment, the container 51 can be disposed so as to extend from a high-temperature heat source, exemplified by a furnace F or the like, to the high-temperature heat source via the outside of the high-temperature heat source.

Unlike the container 11 of the first embodiment, the container 51 has a pipe 51P inside that is defined by the inner wall of the container 51 and can have both ends substantially closed. The inside of the pipe 51P can be filled with a working fluid, and a first heat exchanger 52, a first heat accumulator 53, a second heat exchanger 54, a third heat exchanger 55, a second heat accumulator 56, and a fourth heat exchanger 57 are arranged in order from the first end 51E1 to the second end 51E2 of the pipe 51P.

[Material of container 51]
The material of the container 51 is not particularly limited, and may be the same as the material of the container 11 of the first embodiment.

[Shape of Pipe 51P]
The shape of the conduit 51P is not particularly limited. For example, the shape of the conduit 51P may be a substantially linear shape or a shape including a curved portion.

The substantially linear shape of the conduit 51P can reduce the weakening of the self-excited vibration caused by the variation in phase of the thermoacoustic self-excited vibration in the curved section.

The shape of the conduit 51P preferably includes a curved portion. This makes it easier to attach the heat transport device 5 to a furnace F that does not have a recess or hole to which the heat transport device 5 can be attached, such as a furnace F that is approximately rectangular.

If the shape of the conduit 51P includes curved portions, the number of curved portions is preferably 3 or less, more preferably 2 or less, and even more preferably 1 or less. This makes it possible to both facilitate the arrangement of the heat transport device 5 by providing curved portions and reduce the damping of self-excited vibrations in the curved portions as much as possible.

If the shape of the conduit 51P includes a curved portion, the lower limit of the radius of curvature of the curved portion is preferably 1/4 or more of the length of the conduit 51P, more preferably 1/3 or more of the length of the conduit 51P, and even more preferably 1/2 or more of the length of the conduit 51P. This makes it possible to both facilitate the arrangement of the heat transport device 5 by providing a curved portion and reduce the damping of self-excited vibration in the curved portion as much as possible.

The pipe 51P may be similar to the pipe 11P of the first embodiment in terms of the length, cross-sectional area, etc., and in terms of the ability to connect pressure control means, etc.

[Working fluid]
The working fluid of the heat transport device 5 may be the same as the working fluid of the heat transport device 1 of the first embodiment.

[First heat exchanger 52]
The first heat exchanger 52 may be the same as the first heat exchanger 12 of the first embodiment. The position at which the first heat exchanger 52 is disposed is not particularly limited as long as the first heat exchanger 52, the first heat accumulator 53, the second heat exchanger 54, the third heat exchanger 55, the second heat accumulator 56, and the fourth heat exchanger 57 are disposed in this order from the first end 51E1 to the second end 51E2 of the pipe 51P and the heat of the furnace F or the like can be transferred to the working fluid.

[Regarding the construction of the base of the pin-type heat exchanger integral with the end of the pipe 51P]
When the first heat exchanger 52 is configured as a pin-type heat exchanger, the base can be configured integrally with the first end 51E1 of the pipeline 51P, similarly to the first heat exchanger 12 of the first embodiment. This can provide the same effect as the first heat exchanger 12 of the first embodiment, in which the base is configured integrally with the end of the pipeline.

[First heat accumulator 53]
The first heat accumulator 53 may be similar to the heat accumulator 13. The first heat accumulator 53 has a gap that communicates between the periphery of the first heat exchanger 52 of the pipe 51P and the periphery of the second heat exchanger 54 of the pipe 51P. This allows the first heat accumulator 53 to generate thermoacoustic self-excited vibration in response to a temperature gradient generated inside.

[Location of first heat accumulator 53]
The position at which the first heat storage device 53 is disposed is such that the first heat exchanger 52, the first heat storage device 53, the second heat exchanger 54, the third heat exchanger 55, the second heat storage device 56, and the fourth heat exchanger 57 are disposed in order from the first end 51E1 to the second end 51E2 of the pipeline 51P, and it is preferable that the position at which the first heat storage device relative position, which is the ratio of the distance along the pipeline 51P from the first end 51E1 of the pipeline 51P to the center of the first heat storage device 53 (first distance) divided by the length of the pipeline 51P, satisfies the following condition.

The lower limit of the relative position of the first heat accumulator is preferably 1/12 or more, more preferably 1/10 or more, and even more preferably 1/8 or more. The upper limit of the relative position of the first heat accumulator is preferably 10/24 or less, more preferably 8/24 or less, and even more preferably 7/24 or less. That is, in the heat transport device 5 of this embodiment, the range in which the first heat accumulator 53 can be disposed is wider than the heat accumulator 13 of the first embodiment.

[Second heat exchanger 54]
The second heat exchanger 54 may be the same as the second heat exchanger 14 of the first embodiment. The position at which the second heat exchanger 54 is disposed is not particularly limited as long as the first heat exchanger 52, the first heat accumulator 53, the second heat exchanger 54, the third heat exchanger 55, the second heat accumulator 56, and the fourth heat exchanger 57 are disposed in this order from the first end 51E1 to the second end 51E2 of the pipe 51P, and the heat of the working fluid can be transferred to an external heat medium such as a furnace F.

The heat transport device 5 of this embodiment differs from the heat transport device 1 of the first embodiment in that a third heat exchanger 55, a second heat accumulator 56, and a fourth heat exchanger 57 are disposed inside the pipe 51P.

[Third heat exchanger 55]
The third heat exchanger 55 may be the same as the second heat exchanger 14 of the first embodiment. The position at which the third heat exchanger 55 is disposed is not particularly limited as long as the first heat exchanger 52, the first heat accumulator 53, the second heat exchanger 54, the third heat exchanger 55, the second heat accumulator 56, and the fourth heat exchanger 57 are disposed in this order from the first end 51E1 to the second end 51E2 of the pipe 51P, and the heat of the working fluid can be transferred to an external heat medium such as a furnace F.

[Location of third heat exchanger 55]
The position of the third heat exchanger 55 is not particularly limited as long as it is a position where the heat of the working fluid can be transferred to a heat medium outside the furnace F. For example, when the heat transport device 5 is disposed so as to straddle between the furnace F and the outside of the furnace F, the position of the pipe 51P corresponding to the part of the container 11 that is the periphery of the outside of the furnace F (FIG. 5).

The third heat exchanger 55 is preferably disposed near the second heat accumulator 56. This allows the third heat exchanger 55 to lower the temperature of the working fluid around one end of the second heat accumulator 56 compared to when the third heat exchanger 55 is not disposed near the second heat accumulator 56.

The upper limit of the distance between the end of the third heat exchanger 55 closest to the second heat accumulator 56 and the end of the second heat accumulator 56 closest to the third heat exchanger 55 is preferably 1/40 or less of the length of the pipe 51P, more preferably 1/70 or less of the length of the pipe 51P, and even more preferably 1/100 or less of the length of the pipe 51P. This allows the third heat exchanger 55 to further lower the temperature of the working fluid around one end of the second heat accumulator 56.

[Second heat accumulator 56]
The second heat accumulator 56 may be similar to the heat accumulator 13 of the first embodiment. The second heat accumulator 56 has a gap that communicates the periphery of the fourth heat exchanger 57 of the pipe line 51P with the periphery of the third heat exchanger 55 of the pipe line 51P. This allows the second heat accumulator 56 to generate thermoacoustic self-excited vibration in response to a temperature gradient generated inside.

[Location of second heat accumulator 56]
The position at which the second heat storage device 56 is disposed is such that the first heat exchanger 52, the first heat storage device 53, the second heat exchanger 54, the third heat exchanger 55, the second heat storage device 56, and the fourth heat exchanger 57 are disposed in order from the first end 51E1 to the second end 51E2 of the pipeline 51P, and it is preferable that the second heat storage device relative position, which is the ratio of the distance along the pipeline 51P from the second end 51E2 of the pipeline 51P to the center of the second heat storage device 56 (second distance) divided by the length of the pipeline 51P, is a position that satisfies the same conditions as the above-mentioned first heat storage device relative position.

In the heat transport device 5 of this embodiment, in addition to the transfer of heat from the high-temperature heat source to the heat medium by the first heat exchanger 52, the first heat accumulator 53, and the second heat exchanger 54, the fourth heat exchanger 57, the second heat accumulator 56, and the third heat exchanger 55 also transfer heat from the high-temperature heat source to the heat medium. Therefore, the heat transport device 5 of this embodiment is capable of transferring more heat from the high-temperature heat source to the heat medium.

Therefore, the heat transport device 5 of this embodiment can generate thermoacoustic self-excited vibrations when the relative positions of the first heat accumulator and the second heat accumulator, which are the ratios of the first distance and the second distance divided by the length of the pipe 51P, are in the wide range described above. This can increase the degree of freedom in the arrangement of the first heat exchanger 52 and the fourth heat exchanger 57, which can transfer heat from the high-temperature heat source to the working fluid.

Furthermore, this allows the heat transport device 5 of this embodiment to have greater freedom in the arrangement of the second heat exchanger 54 and the third heat exchanger 55, which can transfer the heat of the working fluid to the heat medium. Therefore, the heat transport device 5 of this embodiment can be configured to match the shape of a high-temperature heat source such as a heating furnace, and can be disposed on the high-temperature heat source to achieve a greater amount of heat transport.

[Fourth heat exchanger 57]
The fourth heat exchanger 57 may be similar to the first heat exchanger 12 of the first embodiment.

[Location of the fourth heat exchanger 57]
The position of the fourth heat exchanger 57 is not particularly limited as long as the first heat exchanger 52, the first heat accumulator 53, the second heat exchanger 54, the third heat exchanger 55, the second heat accumulator 56, and the fourth heat exchanger 57 are arranged in order from the first end 51E1 to the second end 51E2 of the pipe 51P and the heat of the furnace F or the like can be transferred to the working fluid. For example, the position of the pipe 51P corresponding to the part of the container 51 that is the periphery of the furnace F or the like when the heat transport device 5 is arranged so as to straddle between the furnace F or the like and the outside of the furnace F or the like (FIG. 5).

The fourth heat exchanger 57 is preferably disposed near the second heat accumulator 56. This allows the fourth heat exchanger 57 to increase the temperature of the working fluid around one end of the second heat accumulator 56 more than if the fourth heat exchanger 57 were located not near the second heat accumulator 56.

The upper limit of the distance between the end of the fourth heat exchanger 57 closest to the second heat accumulator 56 and the end of the second heat accumulator 56 closest to the fourth heat exchanger 57 is preferably 1/40 or less of the length of the pipe 51P, more preferably 1/70 or less of the length of the pipe 51P, and even more preferably 1/100 or less of the length of the pipe 51P. This allows the fourth heat exchanger 57 to further increase the temperature of the working fluid around one end of the second heat accumulator 56.

[Regarding the construction of the base of the pin-type heat exchanger integral with the end of the pipe 51P]
When the fourth heat exchanger 57 is configured as a pin-type heat exchanger, the base can be configured integrally with the second end 51E2 of the pipeline 51P, similarly to the first heat exchanger 12 of the first embodiment. This can provide the same effect as the first heat exchanger 12 of the first embodiment, in which the base is configured integrally with the end of the pipeline.

[Regarding the pairing of the first heat accumulator 53 and the second heat accumulator 56]
It is preferable that the first heat accumulator 53 and the second heat accumulator 56 have substantially the same length in the direction of the pipe 51P, have substantially the same gap configuration, and the position where the first heat accumulator 53 is disposed and the position where the second heat accumulator 56 is disposed are substantially symmetrical with respect to the center of the pipe 51P. Hereinafter, the above configuration is also referred to as a pair of heat accumulators.

The first heat storage device 53 and the second heat storage device 56 have approximately the same configuration in terms of length and gap, which can improve the maintainability of the heat transport device 5.

Incidentally, a pair of heat accumulators with approximately the same length and gap are thought to generate self-excited vibrations in the same way if the relationship between the temperature gradient of the working fluid around the heat accumulators and the pressure of the working fluid is the same.

Since the position where the first heat storage device 53 is disposed and the position where the second heat storage device 56 is disposed are approximately symmetrical with respect to the center of the pipe 51P, the first heat storage device 53 and the second heat storage device 56 are expected to generate self-excited vibrations in the same manner.

Therefore, in a heat transport device 5 having a pair of heat accumulators, the first heat accumulator 53 and the second heat accumulator 56 can operate in even greater coordination. Thus, in a heat transport device 5 having a pair of heat accumulators, it can be expected that even stronger self-excited vibrations can be generated with even smaller temperature gradients and/or pressures.

[Pressure control means 58]
As in the first embodiment, the heat transport device 5 preferably includes a pressure control means 58 capable of controlling the pressure of the working fluid sealed inside the pipe 51P. The pressure control means 58 may be the same as the pressure control means 15 in the first embodiment.

[High temperature heat source]
The high-temperature heat source is not particularly limited and may be the same as the high-temperature heat source in the first embodiment.

[Effects of Heat Transport Device 5]
In a heat transport device using thermoacoustic self-excited oscillation, the heat accumulator is preferably placed near the high temperature end of the pipe, because the phase of the standing wave generated inside the pipe by the thermoacoustic self-excited oscillation around the heat accumulator affects the generation of self-excited oscillation and the amount of heat transport in the heat accumulator.

Patent Document 1 discloses, as one example of such an arrangement, an arrangement in which the center of the heat storage device in the pipe extension direction is located at a position 12.5% to 25% of the pipe length from the end of the pipe on the high-temperature heat source side.

While it is preferable to place the heat accumulator close to the high-temperature end of the pipeline, from the viewpoint of creating a temperature gradient in the heat accumulator, it is preferable that at least one end of the heat accumulator is not near the high-temperature heat source. However, if the heat transport device is arranged so that the heat accumulator is located near the high-temperature end of the pipeline, and at least one end is not near the high-temperature heat source, most of the container will no longer be near the high-temperature heat source. In other words, most of the container will no longer contribute to the transfer of heat from the high-temperature heat source to the working fluid.

According to the heat transport device 5 of this embodiment, not only the area around the first heat exchanger 52 of the container 51 but also the area around the fourth heat exchanger 57 of the container 51 is in the vicinity of the high-temperature heat source. This allows the first heat exchanger 52 and the fourth heat exchanger 57 of the heat transport device 5 to transfer more heat from the high-temperature heat source to the working fluid.

In the heat transport device 5 of this embodiment, in addition to the transfer of heat to the heat medium by the first heat exchanger 52, the first heat accumulator 53, and the second heat exchanger 54, the fourth heat exchanger 57, the second heat accumulator 56, and the third heat exchanger 55 also transfer this heat to the heat medium.

In the heat transport device 1 of the first embodiment, only the first heat accumulator 13 generates thermoacoustic self-excited vibrations at a position close to the high temperature end (first end 11E1). In contrast, according to the heat transport device 5 of the present embodiment, both the first heat accumulator 53 and the second heat accumulator 56 are positioned at positions close to the high temperature end (first end 51E1, second end 51E2). As a result, in the heat transport device 5 of the present embodiment, both the first heat accumulator 53 and the second heat accumulator 56 generate thermoacoustic self-excited vibrations and can contribute to heat transport.

Therefore, according to the heat transport device 5 of this embodiment, it is possible to simultaneously arrange the heat transport device 5 so that the heat accumulators (first heat accumulator 53, second heat accumulator 56) are disposed near the high-temperature end (first end 51E1, second end 51E2) of the pipe 51P and at least one end is not in the vicinity of the high-temperature heat source, and arrange a larger portion of the container 51 in the vicinity of the high-temperature heat source to reduce the size of the heat transport device in the portion other than the vicinity of the high-temperature heat source, thereby transferring more heat from the high-temperature heat source to the heat medium.

Therefore, the heat transport device 5 of this embodiment can achieve the following objectives.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device 5 in the areas other than the periphery of the high-temperature heat source.

<Summary of the invention>
[First Configuration] Heat storage device and heat transport device [Background Art]
Various means are available for transporting heat from a high temperature source such as a furnace.

As a means for transporting heat from a high-temperature heat source, Patent No. 6807087 discloses a heat transport device that includes a container arranged to straddle a high-temperature heat source and a low-temperature heat bath that is lower in temperature than the high-temperature heat source, a gas sealed in a closed space, and a pipe formed inside with both ends closed; a heat accumulator arranged in the pipe, with pores connecting both ends and insulated from the outside of the container; a first heat exchanger arranged in the pipe adjacent to the high-temperature heat source end of the heat accumulator, which transfers heat from the high-temperature heat source to the heat accumulator; and a second heat exchanger arranged in the pipe adjacent to the low-temperature heat bath end of the heat accumulator, which transfers heat from the heat accumulator to the low-temperature heat bath, and the heat accumulator has a center in the pipe line that is 12.5% to 25% of the pipe line length from the high-temperature heat source end of the pipe.

Patent No. 6807087 makes it possible to provide a heat transport device that is highly safe and can be introduced and used at low cost.

Summary of the Invention
[Problem to be solved by the invention]
Meanwhile, there is a demand for improving the heat transport amount in a heat transport device using thermoacoustic self-excited oscillation as in Patent No. 6807087. It is known that in a device using thermoacoustic self-excited oscillation, the material of the heat accumulator affects the generation of thermoacoustic self-excited oscillation.

Patent No. 6807087 only indicates that the heat storage unit has pores that connect both ends, is insulated from the outside of the container, and is disposed at a specified position within the pipeline, but does not specify the shape or material of the heat storage unit.

If it were possible to improve the shape of the heat storage device so that it is suitable for transporting heat from a high-temperature heat source, further improvements in the performance of the heat transport device could be expected.

The object of the present invention is to improve the amount of heat transport in heat transport using thermoacoustic self-excited vibrations.

[Means for solving the problems]
As a result of intensive research into solving the above problems, the inventors have found that the above object can be achieved by configuring a heat accumulator so that the length of the heat accumulator along the pipe is equal to or greater than a predetermined length, and have completed the present invention. Specifically, the present invention provides the following.

The invention according to the first feature provides a heat storage device for a heat transport device using thermoacoustic self-excited vibration, the heat storage device being substantially cylindrical in shape and including a gap connecting both bottom surfaces, the gap being capable of connecting the periphery of a high-temperature part in the pipe and the periphery of a low-temperature part in the pipe when the heat storage device is disposed in a pipe of a heat transport device that transports heat from a furnace to the outside of the furnace, the heat storage device being capable of generating thermoacoustic self-excited vibration in response to a temperature gradient generated inside the heat storage device due to a temperature difference between the high-temperature part and the low-temperature part when disposed in the pipe, and the length along the pipe is 9% or more of the length of the pipe.

The gap of the invention according to the first feature, when disposed within a pipe of a heat transport device that transports furnace heat to the outside of the furnace, can connect the periphery of the high temperature part of the pipe to the periphery of the low temperature part of the pipe. Thus, in the heat storage device according to the first feature of the invention, a temperature gradient is generated inside when the furnace becomes hot. This temperature gradient enables the heat storage device to generate thermoacoustic self-excited vibrations that can transport furnace heat to the outside.

The inventors have found that there are cases where the results of numerical calculations regarding thermoacoustic self-excited vibrations differ greatly from the measured values in an actual device. After extensive investigation, the inventors have found that the above-mentioned differences can be caused by the difference between the actual device and the numerical calculations, in that part of the heat storage device in the actual device also functions as a heat exchanger.

In a heat transport device applied to a high-temperature furnace, the means for transferring heat from the furnace to the working fluid is more important than in a thermoacoustic device that operates at low temperatures near or below room temperature. According to the invention relating to the first feature, the length of the heat accumulator along the pipe is 9% or more of the pipe length, so that the portion of the heat accumulator that functions as a heat exchanger can be made larger.

As a result, the heat storage device of the first aspect of the invention can function as an additional means for transferring heat from the furnace to the working fluid. Thus, the heat storage device of the first aspect of the invention can contribute to even greater transport of heat from the furnace.

Therefore, according to the first aspect of the invention, it is possible to improve the amount of heat transport in heat transport using thermoacoustic self-excited vibrations.

The second aspect of the invention is the first aspect of the invention, which provides a heat storage device, the material of which includes a thermally anisotropic material having anisotropic thermal conductivity, and the heat storage device is configured so that the direction in which the thermal conductivity of the thermally anisotropic material is low is substantially the same as the direction along the pipe.

In a heat transport device using self-excited vibration, the greater the temperature gradient inside the heat accumulator, the stronger the self-excited vibration of the generated thermoacoustic sound. Also, in a heat transport device using self-excited vibration, the easier it is to transfer heat between the heat accumulator and the working fluid, the stronger the self-excited vibration of the generated thermoacoustic sound.

However, while lowering the thermal conductivity of the heat accumulator is effective in reducing the loss of temperature gradients inside the heat accumulator, increasing the thermal conductivity of the heat accumulator is effective in facilitating heat transfer between the heat accumulator and the working fluid.

Therefore, it is not easy to achieve both of these conditions and strengthen the self-excited vibration of the generated thermoacoustic sound. In addition, the heat resistance of the heat storage device is also important for a heat transport device that transports the heat of the furnace to the outside of the furnace.

According to the second aspect of the invention, the material of the heat storage device includes an anisotropic thermally conductive material, and the heat storage device is configured so that the direction in which the thermal conductivity of the anisotropic thermally conductive material is low is substantially the same as the direction along the pipe.

The invention relating to the second feature can achieve both: by using the properties of the thermally conductive anisotropic material described above to keep the thermal conductivity low in the direction of the temperature gradient, thereby preventing the thermal conduction in the heat storage device from eliminating the temperature gradient; by realizing high thermal conductivity in a direction different from the direction of the temperature gradient, it is possible to facilitate heat transfer between the heat storage device and the working fluid; and by realizing a heat storage device with high heat resistance.

Therefore, according to the second aspect of the invention, it is possible to improve the amount of heat transport in heat transport using thermoacoustic self-excited vibrations.

The invention according to the third feature provides a heat transport device comprising a heat accumulator according to the first or second feature, and a container having a pipe inside that can be arranged to straddle a high-temperature heat source and an outside of the high-temperature heat source and can have both ends substantially closed, the inside of the pipe can be filled with a working fluid, a first heat exchanger, the heat accumulator, and a second heat exchanger are arranged in this order from the first end to the second end of the pipe, the first heat exchanger is arranged at a position where it can transfer heat from the high-temperature heat source to the working fluid, the heat accumulator is arranged so that the gap connects the periphery of the first heat exchanger in the pipe to the periphery of the second heat exchanger in the pipe, and the second heat exchanger is capable of transferring heat from the working fluid to a heat medium outside the high-temperature heat source.

According to the third aspect of the invention, the working fluid on the first heat exchanger side of the heat accumulator is hotter than the working fluid inside the heat accumulator due to the heat transferred from the high-temperature heat source by the first heat exchanger. Also, the working fluid on the second heat exchanger side of the heat accumulator is colder than the working fluid inside the heat accumulator due to the heat transferred by the second heat exchanger to a heat medium outside the high-temperature heat source.

Therefore, according to the third aspect of the invention, the working fluid around the heat accumulator has a temperature gradient in a direction along the piping of the heat accumulator. This enables the heat accumulator to generate thermoacoustic self-excited vibrations according to the relationship between the temperature gradient of the working fluid along this direction and the pressure of the working fluid.

This self-excited vibration promotes heat transport in the pipe from the periphery of the first heat exchanger to the periphery of the second heat exchanger. The stronger the self-excited vibration that is generated, the more this heat transport is promoted. According to the invention relating to the third feature, since the heat accumulator is the heat accumulator relating to the first or second feature, stronger thermoacoustic self-excited vibration can be generated than when using a heat accumulator that has not been improved according to the heat transport device, such as by enlarging the portion that functions as a heat exchanger.

Therefore, according to the third aspect of the invention, the stronger thermoacoustic self-excited oscillations that are generated further promote heat transport from the high-temperature heat source end to the low-temperature heat bath end.

Therefore, according to the third aspect of the invention, it is possible to improve the amount of heat transport in heat transport using thermoacoustic self-excited vibrations.

The fourth aspect of the invention provides a furnace comprising the heat transport device of the third aspect of the invention, the heat transport device being disposed so as to straddle the interior and exterior of the furnace.

According to the fourth aspect of the invention, a heat transport device having a structure suitable for transporting heat from a high-temperature heat source such as a furnace is arranged to span the inside and outside of the furnace, thereby improving the amount of heat transport in the furnace using self-excited thermoacoustic vibrations.

Therefore, according to the fourth aspect of the invention, it is possible to improve the amount of heat transport in heat transport using thermoacoustic self-excited vibrations.

[Effect of the invention]
According to the present invention, it is possible to improve the amount of heat transport in heat transport using self-excited thermoacoustic oscillations.

[Second Configuration] Heat Transport Device [Background Art]
Various means are used to transport heat from a high-temperature heat source such as a furnace. One of the functions required for such means is the ability to adjust the amount of heat transport.

Patent No. 6807087 provides a heat transport device that is highly safe, can be introduced and used at low cost, and has adjustable heat transport rate.

Summary of the Invention
[Problem to be solved by the invention]
Incidentally, it is known that the performance of various devices using thermoacoustics can be improved by increasing the pressure of the working fluid above normal pressure.

The adjustment means in Patent No. 6807087 is disposed inside the container so that it can move back and forth freely. Therefore, Patent Document 1 requires a drive source for moving the adjustment means back and forth. If such a drive source is provided inside the container, the internal structure of the heat transport device will become complicated, and there is a concern that maintenance of the heat transport device will become difficult.

[Means for solving the problems]
As a result of intensive research into solving the above problems, the inventors have found that the above object can be achieved by providing a working fluid pressure control means that is capable of performing pressure control to weaken the self-excited oscillation in response to a command to reduce heat transport, and that is capable of pressure control to strengthen the self-excited oscillation in response to a command to increase heat transport, and have thus completed the present invention. Specifically, the present invention provides the following.

[Effect of the invention]
According to the present invention, in a heat transport device using thermoacoustic self-excited vibration, the following objects can be simultaneously achieved.
(A) Improvement of heat transport rate in heat transport using self-excited vibration.
(B) The amount of heat transport can be adjusted.
(C) Improved maintainability of heat transport devices.

[Third Configuration] Heat Transport Device [Background Art]
Various means are available for transporting heat from a high temperature source such as a furnace.

Summary of the Invention
[Problem to be solved by the invention]
Meanwhile, there is a demand for improving the amount of heat transport in the heat transport device as disclosed in Patent Document 1. It is generally known that the shape of a heat exchanger affects the transfer of heat.

However, Patent No. 6807087 only shows that the first heat exchanger transfers heat from the high-temperature heat source to the heat storage device, and does not specify the shape of the first heat exchanger.

If the first heat exchanger can be configured with a shape suitable for heat transport using self-excited vibration, further performance improvements can be expected.

[Means for solving the problems]
As a result of intensive research into solving the above problems, the inventors have found that the above object can be achieved by providing a heat exchanger that transfers heat from a high-temperature heat source to a working fluid with a plurality of rod-shaped heat receiving parts, and have completed the present invention. Specifically, the present invention provides the following.

The invention according to the first aspect provides a heat transport device that includes a container that can be disposed between a high-temperature heat source and the outside of the high-temperature heat source and has a pipe inside that can be substantially closed at both ends, the inside of the pipe can be filled with a working fluid, a first heat exchanger, a heat accumulator, and a second heat exchanger are disposed in this order from the first end of the pipe to the second end, the first heat exchanger is disposed at a position where it can transfer heat from the high-temperature heat source to the working fluid, and has a plurality of rod-shaped heat receiving parts whose longitudinal direction is approximately aligned with the direction along the pipe, the heat accumulator has a gap that connects the periphery of the first heat exchanger in the pipe to the periphery of the second heat exchanger in the pipe, and is capable of generating thermoacoustic self-excited vibrations, and the second heat exchanger is capable of transferring heat from the working fluid to a heat medium outside the high-temperature heat source.

According to the invention relating to the first feature, the working fluid on the first heat exchanger side of the heat accumulator is hotter than the working fluid inside the heat accumulator due to the heat transferred by the first heat exchanger from the high-temperature heat source. Also, the working fluid on the second heat exchanger side of the heat accumulator is colder than the working fluid inside the heat accumulator due to the heat transferred by the second heat exchanger to the heat medium outside the high-temperature heat source.

Therefore, according to the first aspect of the invention, the working fluid around the heat accumulator has a temperature gradient in a direction along the piping of the heat accumulator. This enables the heat accumulator to generate thermoacoustic self-excited vibrations according to the relationship between the temperature gradient of the working fluid along this direction and the pressure of the working fluid.

This self-excited vibration promotes heat transport in the pipe from the area around the first heat exchanger to the area around the second heat exchanger. At this time, the heat from the high-temperature heat source first moves to the container. Next, the heat that has moved to the container moves to the first heat exchanger via radiation and thermal conduction. The heat that has moved to the first heat exchanger then moves to the working fluid via thermal conduction.

Between two objects with different temperatures, the amount of heat transfer due to thermal conduction is proportional to the difference in their absolute temperatures. On the other hand, the amount of heat transfer due to radiation is proportional to the difference in the fourth power of the absolute temperatures. Therefore, at high temperatures where the absolute temperature is high, the amount of heat transfer due to radiation is expected to be greater than the amount of heat transfer due to thermal conduction.

A plate-type heat exchanger, in which plates are arranged approximately parallel to each other, is known as a heat exchanger that transfers heat to a gas. When using a plate-type heat exchanger to form a first heat exchanger, there is a concern that plates that are blocked from the inner wall of the container by other plates will not be able to receive sufficient radiation. Therefore, there may be room for further improvement in the plate-type heat exchanger in terms of transferring heat from a high-temperature heat source to the heat exchanger by radiation.

The invention relating to the first characteristic has a plurality of rod-shaped heat receiving parts whose longitudinal direction is approximately aligned with the direction along the pipeline. This allows the heat receiving parts to receive the radiation from the container without blocking the radiation from the container. This can enhance the transfer of heat from the container to the first heat exchanger. Thus, according to the invention relating to the first characteristic, the first heat exchanger can transfer even more heat from the high-temperature heat source to the working fluid.

By transferring more heat from the high-temperature heat source to the working fluid, the invention according to the first aspect can further increase the temperature gradient in the heat accumulator. Typically, as the temperature gradient in the heat accumulator increases, the self-excited vibrations that are generated become stronger. Thus, the invention according to the first aspect can improve the amount of heat transport in heat transport using self-excited vibrations.

The second aspect of the invention is the first aspect of the invention, which provides a heat transport device in which at least a portion of the heat receiving portion is disposed at the first end portion.

A plate heat exchanger in which plates are arranged inside a pipeline can be arranged inside the pipeline without requiring any additional structure for arranging the plates. On the other hand, the rod-shaped heat receiving part of the present invention may require a base for arranging the heat receiving part.

The heat transport device of the present invention transports heat by thermoacoustic self-excited vibration in the working fluid. Incidentally, self-excited vibration has the properties of a sound wave with the working fluid as a medium. Therefore, if there is a structure inside the pipe that obstructs the sound waves, the thermoacoustic self-excited vibration may be obstructed. This may inhibit the generation of more powerful self-excited vibration. Therefore, the above-mentioned base may prevent the generation of more powerful self-excited vibration.

In the invention relating to the second feature, since the heat receiving portion is disposed at the first end, it is possible to prevent the base that is separately constructed within the pipe from interfering with the sound waves. Therefore, it is possible to further reduce the base's inhibition of the thermoacoustic self-excited vibration.

Among thermoacoustic devices, a thermoacoustic device that is shaped like a straight tube is also called a standing wave type thermoacoustic device. In a conventional standing wave type thermoacoustic device, the high temperature side heat exchanger is configured as, for example, a plate type heat exchanger, and is placed inside the pipe near the heat accumulator away from the high temperature end of the pipe. This type of configuration has room for further improvement in terms of increasing the surface area of the heat exchanger.

According to the second feature of the invention, since the heat receiving portion is disposed at the first end, the area of the heat receiving portion can be made larger than in a configuration in which the high-temperature side heat exchanger is disposed near the heat storage device away from the high-temperature side end of the pipe. This can further increase the heat transport capacity of the heat transport device.

The third aspect of the invention is the first aspect of the invention, which provides a heat transport device in which the spacing between the heat receiving parts is equal to or greater than the thickness of the thermal boundary layer in the working fluid.

If the distance between the heat receiving parts is less than the thickness of the thermal boundary layer in the working fluid, the heat receiving parts may inhibit the thermoacoustic self-excited oscillations.

According to the third aspect of the invention, the spacing between the heat receiving parts is equal to or greater than the thickness of the thermal boundary layer in the working fluid, so that the heat receiving parts can be further reduced from impeding the thermoacoustic self-excited vibration.

The fourth aspect of the invention provides a furnace comprising a heat transport device according to any one of the first to third aspects of the invention, the heat transport device being disposed so as to span between the inside of the furnace and the outside of the furnace.

[Fourth Configuration] Heat transport device [Background Art]
Various means are available for transporting heat from a high temperature source such as a furnace.

Summary of the Invention
[Problem to be solved by the invention]
Incidentally, in a heat transport device using thermoacoustic self-excited vibration as in Japanese Patent No. 6807087, there is a demand for improving the amount of heat transport.

Patent No. 6807087 transfers heat from the high-temperature heat source to the heat storage device using only the first heat exchanger adjacent to the end of the high-temperature heat source.

If it were possible to configure the container in a shape that would allow for heat transport using self-excited vibrations, and to more efficiently transfer heat from the high-temperature heat source to the heat transport device, further improvements in performance could be expected.

An object of the present invention is to achieve both of the following objectives.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device in areas other than the periphery of the high-temperature heat source.

[Means for solving the problems]
As a result of intensive research into solving the above problems, the inventors have found that the above object can be achieved by configuring a heat transport device that can be arranged so as to extend from a high-temperature heat source to the high-temperature heat source via the outside of the high-temperature heat source, and providing heat accumulators with a temperature gradient on both ends of the device, thereby completing the present invention. Specifically, the present invention provides the following.

The invention relating to the first feature comprises a container having an internal pipe that can be arranged to extend from a high-temperature heat source through the outside of the high-temperature heat source to the high-temperature heat source, both ends of which can be substantially closed, the inside of the pipe can be filled with a working fluid, and a first heat exchanger, a first heat accumulator, a second heat exchanger, a third heat exchanger, a second heat accumulator, and a fourth heat exchanger are arranged in this order from the first end of the pipe to the second end, and the first heat exchanger and the fourth heat exchanger are arranged in positions where heat from the high-temperature heat source can be transferred to the working fluid. The first heat accumulator has a gap that connects the periphery of the first heat exchanger of the pipe with the periphery of the second heat exchanger of the pipe and is capable of generating thermoacoustic self-excited vibrations in response to a temperature gradient generated inside, the second heat accumulator has a gap that connects the periphery of the fourth heat exchanger of the pipe with the periphery of the third heat exchanger of the pipe and is capable of generating thermoacoustic self-excited vibrations in response to a temperature gradient generated inside, and the second heat exchanger and the third heat exchanger are capable of transferring heat from the working fluid to a heat medium outside the high-temperature heat source.

Therefore, according to the first aspect of the invention, the working fluid around the heat accumulator has a temperature gradient in a direction along the piping of the heat accumulator. This enables the heat accumulator to generate thermoacoustic self-excited vibrations according to the relationship between the temperature gradient of the working fluid along this direction and the pressure of the working fluid. The fourth heat exchanger, second heat accumulator, and third heat exchanger are similar to the first heat exchanger, first heat accumulator, and second heat exchanger.

The second heat accumulator is capable of generating thermoacoustic self-excited vibrations according to the relationship between the temperature gradient of the working fluid along this direction and the pressure of the working fluid. This self-excited vibration promotes heat transport in the pipe from the periphery of the first heat exchanger to the periphery of the second heat exchanger, and heat transfer from the periphery of the fourth heat exchanger to the periphery of the third heat exchanger.

In a heat transport device that uses thermoacoustic self-excited vibration, it is preferable to place the heat accumulator close to the high-temperature end of the pipe. Patent Document 1 discloses, as an example of such an arrangement, an arrangement in which the center of the heat accumulator in the pipe extension direction is located at a position 12.5% to 25% of the pipe length from the high-temperature heat source end of the pipe.

From the viewpoint of creating a temperature gradient in the heat storage device, it is preferable that at least one end of the heat storage device is not in the vicinity of the high-temperature heat source. However, if the heat transport device is arranged so that the heat storage device is located near the high-temperature end of the pipe and at least one end is not in the vicinity of the high-temperature heat source, most of the container will no longer be in the vicinity of the high-temperature heat source. In other words, most of the container will no longer contribute to the transfer of heat from the high-temperature heat source to the working fluid.

According to the first aspect of the invention, not only the periphery of the first heat exchanger of the container but also the periphery of the fourth heat exchanger of the container is the periphery of the high-temperature heat source. This allows the first and fourth heat exchangers of the heat transport device to transfer more heat from the high-temperature heat source to the working fluid.

And according to the first aspect of the invention, in addition to the heat transfer to the heat medium by the first heat exchanger, the first heat accumulator, and the second heat exchanger, the fourth heat exchanger, the second heat accumulator, and the third heat exchanger also transfer this heat to the heat medium.

Therefore, according to the first aspect of the invention, by arranging the heat transport device so that the heat storage device is located near the high temperature end of the pipe and at least one end is not in the vicinity of the high temperature heat source, and by arranging a larger portion of the container in the vicinity of the high temperature heat source to reduce the size of the heat transport device in the portion other than the vicinity of the high temperature heat source, it is possible to transfer more heat from the high temperature heat source to the heat medium.

Therefore, according to the first aspect of the invention, the following objects can be achieved simultaneously.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device in areas other than the periphery of the high-temperature heat source.

The second aspect of the invention is the first aspect of the invention, and provides a heat transport device in which the first heat storage device and the second heat storage device have substantially the same length in the direction of the pipeline, substantially the same gap configuration, and the position where the first heat storage device is disposed and the position where the second heat storage device is disposed are substantially symmetrical with respect to the center of the pipeline.

According to the second aspect of the invention, the heat storage units have approximately the same length and gap configuration. This can improve the maintainability of the heat transport device.

Incidentally, a pair of heat accumulators with approximately the same length and gap are thought to generate self-excited vibrations in the same way if the relationship between the temperature gradient of the working fluid inside the heat accumulator and the pressure of the working fluid is the same.

According to the second feature of the invention, the position where the first heat accumulator is disposed and the position where the second heat accumulator is disposed are substantially symmetrical with respect to the center of the pipe. This makes it possible to expect that the first heat accumulator and the second heat accumulator will generate self-excited vibrations in the same way.

Therefore, in the second aspect of the invention, the first heat storage device and the second heat storage device can operate in even greater coordination. Therefore, according to the second aspect of the invention, it is possible to expect that even stronger self-excited vibrations can be generated with even smaller temperature gradients and/or pressures.

Therefore, according to the second aspect of the invention, the following objects can be achieved simultaneously.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device in areas other than the periphery of the high-temperature heat source.

The third aspect of the invention is the first or second aspect of the invention, which provides a heat transport device in which the distance (first distance) from the first end to the end closest to the first end of the first heat storage device and the distance (second distance) from the second end to the end closest to the second end of the second heat storage device are 1/12 to 5/12 of the length of the pipe.

According to the third aspect of the invention, in addition to the transfer of heat from the high-temperature heat source to the heat medium by the first heat exchanger, the first heat accumulator, and the second heat exchanger, the fourth heat exchanger, the second heat accumulator, and the third heat exchanger also transfer heat from the high-temperature heat source to the heat medium. Therefore, the third aspect of the invention makes it possible to transfer more heat from the high-temperature heat source to the heat medium.

Therefore, the invention relating to the third feature can generate thermoacoustic self-excited vibrations in a wide range of the first and second distances, from 1/12 to 5/12 of the length of the pipe. This can increase the degree of freedom in the arrangement of the first and fourth heat exchangers that can transfer heat from the high-temperature heat source to the working fluid.

Furthermore, this allows the invention according to the third feature to increase the degree of freedom in the arrangement of the second and third heat exchangers capable of transferring heat from the working fluid to the heat medium. Therefore, the invention according to the third feature makes it possible to configure a heat transport device to match the shape of a high-temperature heat source such as a heating furnace, and to arrange the device on the high-temperature heat source so as to achieve a larger amount of heat transport.

Therefore, according to the third aspect of the invention, the following objects can be achieved simultaneously.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device in areas other than the periphery of the high-temperature heat source.

The fourth aspect of the invention provides a furnace comprising the heat transport device of the first aspect of the invention, the heat transport device being arranged so as to pass from the inside of the furnace through the outside of the furnace to the inside of the furnace.

According to the invention relating to the fourth feature, a heat transport device having a structure suitable for transporting heat from a high-temperature heat source such as a furnace is arranged so that it passes from the inside of the furnace to the outside and then back to the inside again, thereby forming a furnace, and therefore the amount of heat transport in the heat transport using thermoacoustic self-excited vibration in the furnace is improved. This also makes it possible to reduce the size of the heat transport device in the areas other than the periphery of the high-temperature heat source.

Therefore, according to the fourth aspect of the invention, the following objects can be achieved simultaneously.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device in areas other than the periphery of the high-temperature heat source.

[Effect of the invention]
According to the present invention, the following objects can be achieved simultaneously.
(A) To improve the amount of heat transport in heat transport using self-excited thermoacoustic vibrations.
(B) Reducing the size of the heat transport device in areas other than the periphery of the high-temperature heat source.

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

<Heat Transport Device 1 of First Embodiment>
According to the above-described first embodiment, the heat transport devices 1 of Examples 1 to 8 were prepared.

Example 1: Configuration using a 0.133 m long heat accumulator A round tube (high temperature heat source side round tube) with a total length of 0.45 m and an outer diameter of 0.065 m and an internal duct with an inner diameter of 0.062 m was made of Haynes 230 alloy. One end of the round tube was plugged with the alloy.

The pin-type heat exchanger was constructed to have a length of 0.086 m and 20 rod-shaped heat receiving parts. Each of these rod-shaped heat receiving parts was rod-shaped, 0.76 m long and 0.002 m in diameter, and was placed at intervals of 0.002 m to 0.003 m on a base made of two stacked disks with a diameter of 0.060 m.

As a result, a gap was formed between the disk-shaped base and the pipe. The ratio of this gap when viewed from the direction of the pipe was approximately 0.063. This allowed the working fluid to move between the space around the closed end of the round tube and the space in which the pin-type heat exchanger was located.

A 0.133m long heat storage tank was constructed using a ceramic honeycomb (manufactured by Nippon Gaishi Co., Ltd.). In the ceramic honeycomb, numerous holes were formed so that both bottom surfaces were connected, the flow path radius of each hole was 0.005m, and the porosity of the heat storage tank was 0.81. The heat storage tank was disposed in the above-mentioned pipe line so that one bottom surface of the heat storage tank was in approximately the same position as the unblocked end of the above-mentioned pipe line. The pin-type heat exchanger was also disposed in the above-mentioned pipe line so that one end of the pin-type heat exchanger was in contact with the other bottom surface of the heat storage tank.

By disposing the above-mentioned pin-type heat exchanger and the above-mentioned heat accumulator in the above-mentioned pipe, a high-temperature heat source side round tube was obtained in which a pin-type heat exchanger equivalent to the first heat exchanger 12 and the above-mentioned heat accumulator equivalent to the heat accumulator 13 were disposed inside the pipe having a length of 0.450 m and an inner diameter of 0.062 m.

A shell-and-tube gas-liquid heat exchanger with a length of 0.070 m and a porosity of 0.38 was constructed using SUS304, an austenitic stainless steel. The gas-liquid heat exchanger was connected to the unblocked end of the round tube on the high-temperature heat source side. This resulted in an installed round tube with a length of 0.520 m and an inner diameter of 0.062 m, in which a pin-type heat exchanger equivalent to the first heat exchanger 12, the above-mentioned heat accumulator equivalent to the heat accumulator 13, and the above-mentioned gas-liquid heat exchanger equivalent to the second heat exchanger 14 were arranged.

A round tube (external round tube) with a total length of 1.220 m and an outer diameter of 0.065 m, with a piping line with an inner diameter of 0.06 m formed inside, was made of Haynes 230 alloy. One end of the round tube was blocked with the alloy. An exhaust valve capable of connecting a commercially available compressor was provided at this blocked end. The external round tube was then connected to the above-mentioned installed round tube to form the container 11 of the heat transport device 1 of embodiment 1.

The heat transport device 1 of Example 1 was obtained by the above-mentioned series of steps. The heat transport device 1 of Example 1 has a container 11 with a length of 1.740 m and an outer diameter of 0.065 m. The container 11 of the heat transport device 1 of Example 1 has a pipe 11P with an inner diameter of 0.062 m formed therein. In this pipe 11P, a pin-type heat exchanger corresponding to the first heat exchanger 12, the above-mentioned heat accumulator corresponding to the heat accumulator 13, and the above-mentioned gas-liquid heat exchanger corresponding to the second heat exchanger 14 are arranged in this order. Furthermore, in the heat transport device 1 of Example 1, the relative position of the heat accumulator was approximately 0.220.

[Example 2] Configuration in which the heat accumulator of Example 1 is replaced with a heat accumulator having a length of 0.172 m The heat transport device 1 of Example 2 was configured in which the heat accumulator of Example 1 was replaced with a heat accumulator having a length of 0.172 m. In the heat transport device 1 of Example 2, the relative position of the heat accumulator was about 0.209.

[Example 3] Configuration in which the heat accumulator of Example 1 is replaced with a heat accumulator having a length of 0.208 m The heat transport device 1 of Example 3 was configured in which the heat accumulator of Example 1 was replaced with a heat accumulator having a length of 0.208 m. In the heat transport device 1 of Example 3, the relative position of the heat accumulator was about 0.199.

[Example 4] Configuration in which the heat accumulator of Example 1 is replaced with a heat accumulator having a length of 0.250 m The heat transport device 1 of Example 3 was configured in which the heat accumulator of Example 1 was replaced with a heat accumulator having a length of 0.250 m. In the heat transport device 1 of Example 4, the relative position of the heat accumulator was about 0.187.

[Example 5] Configuration in which the heat accumulator of Example 1 is replaced with a heat accumulator having a length of 0.369 m The heat transport device 1 of Example 5 was configured in which the heat accumulator of Example 1 was replaced with a heat accumulator having a length of 0.369 m. In the heat transport device 1 of Example 5, the relative position of the heat accumulator was about 0.153.

[Example 6] Configuration in which the pin-type heat exchanger of Example 3 is replaced with a pin-type heat exchanger having 40 heat receiving parts A heat transport device 1 of Example 6 was constructed in which the pin-type heat exchanger of Example 3 was replaced with a pin-type heat exchanger having 40 rod-shaped heat receiving parts with the same dimensions. Each of these rod-shaped heat receiving parts was rod-shaped with a length of 0.76 m and a diameter of 0.002 m, and was disposed at intervals of 0.001 m to 0.002 m on a base made of two stacked disks with a diameter of 0.060 m.

[Example 7] Configuration in which the high-temperature heat source side round tube of Example 3 is replaced with a round tube of 0.300 m in length The heat transport device 1 of Example 7 was configured by replacing the high-temperature heat source side round tube of Example 3 with a Haynes 230 alloy round tube of 0.300 m in length. The total length of the heat transport device 1 of Example 7 was 1.590 m. The relative position of the heat accumulator was about 0.123.

[Example 8] Configuration in which the pin-type heat exchanger of Example 7 is replaced with a plate-type heat exchanger having a length of 0.050 m A heat transport device 1 of Example 8 was configured in which the pin-type heat exchanger of Example 7 was replaced with a plate-type heat exchanger having a length of 0.050 m and 12 plates.

<Evaluation experiment>
In order to evaluate the heat transport devices 1 of Examples 1 to 8, the following heat transport amount measurement experiments and pressure control experiments were carried out.

[Heat transport measurement experiment]
The heat transport amount measurement experiment is an experiment in which the heat transport device 1 of Examples 1 to 8 is arranged across a high-temperature heat source of 650°C to 900°C and its outside, and the heat transport amount and the strength of the self-excited vibration (magnitude of pressure amplitude) are measured when the pressure of the working fluid is 0.7 MPa.

In the heat transport amount measurement experiment, the heat transport device 1 was arranged so that the portion of the round tube part on the high-temperature heat source side minus 0.168 m was the inner part of the electric furnace. The remaining part of the round tube part on the high-temperature heat source side was arranged at the position of the insulation material provided on the outer periphery of the electric furnace. Air, which is the working fluid, was sealed inside the pipe of the heat transport device 1.

The gas-liquid heat exchanger of the heat transport device 1 was connected to a commercially available chiller, and tap water cooled to 10°C was continuously supplied as a heat medium. The heat transport device 1 was connected to a commercially available compressor via an exhaust valve. This constituted the pressure control means 15 of the first embodiment. Then, in response to a command to increase the amount of heat transport, the compressor increased the pressure of the air sealed inside the pipe to 0.7 MPa.

The interior of the electric furnace was heated to a target temperature set in 50°C increments in the range of 650°C to 900°C. This caused thermoacoustic self-excited oscillations to be generated in the heat accumulator. When thermoacoustic self-excited oscillations were being generated, the amount of heat transported by the heat transport device 1 was measured by multiplying the product of the flow rate of the heat medium passing through the gas-liquid heat exchanger and the temperature change of the heat medium before and after passing through the gas-liquid heat exchanger by the specific heat of water.

[Pressure control experiment]
As in the heat transport amount measurement experiment, a pressure control experiment was conducted to control heat transport by pressure control for the heat transport device 1 of Example 6, which was disposed so as to straddle a high-temperature heat source and its outside. The pressure control experiment included a preliminary experiment, a pressurization experiment, and a depressurization experiment, which are described below.

[Preliminary experiment]
In the preliminary experiment, the heat transport device 1 of Example 7 was disposed across a high-temperature heat source of 850° C. and its outside, and the amount of heat transport was measured when the pressure of the working fluid was from 0 MPaG to 0.6 MPaG.

[Pressure experiment]
In the pressurization experiment, the heat transport device 1 of Example 7 was arranged so as to straddle a high-temperature heat source of 950°C and its exterior, and the pressure of the air sealed inside the pipe was increased from 0 MPaG to 0.6 MPaG in response to a command to increase the amount of heat transport.

[Decompression experiment]
The pressure reduction experiment involved placing the heat transport device 1 of Example 7 across a high-temperature heat source of 950°C and its exterior, and reducing the pressure of the air sealed inside the pipeline from 0.6 MPaG to 0 MPaG in response to a command to reduce the amount of heat transport.

<Results and Discussion>
Table 1 shows the heat transport amount measured in the heat transport device 1 of Examples 1 to 8 in the heat transport amount measurement experiment.

FIG. 6 is a graph showing the relationship between the length of the heat storage unit and the amount of heat transport for each temperature of the furnace F in Examples 1 to 5. In FIG. 6, each data group corresponding to Examples 1 to 5 is surrounded by a dashed line. When Examples 1 to 5, which each have a different heat storage unit length, are arranged in ascending order of heat storage unit length, the order is Example 1, Example 2, Example 3, Example 4, and Example 5.

At high temperatures of 800°C or higher, the heat transport rate begins to increase from Example 1, where the heat storage device length is 0.133 m, to Example 2, where the heat storage device length is 0.172 m. On the other hand, at temperatures of 700°C or lower, there is no increase in the heat transport rate from Example 1, where the heat storage device length is 0.133 m, to Example 2, where the heat storage device length is 0.172 m. 0.133 m corresponds to approximately 7.6% of the pipe length of 1.740 m in Example 1. 0.172 m corresponds to approximately 9.9% of the pipe length of 1.740 m in Example 2. Therefore, it may be possible to find a threshold value at or around 9% of the pipe length, which is approximately halfway between 7.6% and 9.9%, at which the portion of the heat storage device that functions as a heat exchanger increases when the high-temperature heat source (furnace F) changes from 700°C or lower to 800°C or higher.

Furthermore, at high temperatures of 800°C or higher, the amount of heat transport increases significantly from Example 3, where the heat storage unit length is 0.208 m, to Example 4, where the heat storage unit length is 0.250 m. 0.208 m corresponds to approximately 11.9% of the pipe length of 1.740 m in Example 3. 0.172 m corresponds to approximately 14.3% of the pipe length of 1.740 m in Example 4. Therefore, it may be possible to find a threshold value at or around 13% of the pipe length, which is roughly halfway between 11.9% and 14.3%, at which the portion of the heat storage unit that functions as a heat exchanger becomes large.

On the other hand, from Example 4, where the heat storage unit length is 0.250 m, to Example 5, where the heat storage unit length is 0.369 m, the amount of heat transport decreases regardless of temperature, even though the portion of the heat storage unit that functions as a heat exchanger becomes larger than in Example 4. This is thought to be because in Example 5, although the heat storage unit relative position (approximately 0.153) satisfies the condition of 2/25 (0.08) or more, it no longer satisfies the condition of 4/25 (0.16) or more.

Examples 3 and 6 differ in the number of rod-shaped heat receiving parts of the pin-type heat exchanger and the spacing between the rod-shaped heat receiving parts. The heat transport amount in Example 6 is less than that in Example 3. In Example 3, the spacing between the rod-shaped heat receiving parts is 0.002 m to 0.003 m, which is wider than in Example 6, so the rod-shaped heat receiving parts are less likely to block radiation to other rod-shaped heat receiving parts, resulting in a greater heat transport amount than in Example 6.

Example 3 and Example 7 differ in the length of the pipe and the relative position of the heat storage unit. The amount of heat transport in Example 7 is less than that in Example 3. The relative position of the heat storage unit in Example 3 is approximately 0.199, which satisfies all of the conditions of 2/25 (0.08) or more and 4/25 (0.16) or more. On the other hand, the relative position of the heat storage unit in Example 7 is approximately 0.123, which satisfies the condition of 2/25 (0.08) or more, but does not satisfy the condition of 4/25 (0.16) or more.

Example 7 and Example 8 differ in the member corresponding to the first heat exchanger 12. The heat transport amount in Example 8 is less than that in Example 7. In Example 7, the member corresponding to the first heat exchanger 12 is a pin-type heat exchanger, so the rod-shaped heat receiving part is less likely to block radiation. As a result, the heat receiving part in Example 7 can more effectively receive heat by radiation than the heat receiving part of a plate-type heat exchanger, and it is believed that the heat transport amount is greater than that in Example 8.

Figure 7 is a graph showing the relationship between the temperature of furnace F and the amount of heat transport in Examples 3 and 7. The black circles represent Example 3. The open triangles represent Example 7. In both Examples 3 and 7, the amount of heat transport increases as the temperature of furnace F increases. At temperatures below 800°C, the heat transport amounts of Examples 7 and 3 are roughly the same, but at temperatures above 800°C, Example 3 is superior in terms of the amount of heat transport to Example 7. It is believed that due to the difference in the relative positions of the heat accumulators described above, Example 3 exhibits superior capacity in terms of the amount of heat transport at high temperatures, which is the subject of the present invention.

Figure 8 is a graph showing the relationship between the temperature of furnace F and the strength of self-excited vibration (magnitude of pressure amplitude) in Examples 3 and 7. The black circles represent Example 3. The open triangles represent Example 7. The pressure amplitude in Example 3 is smaller than that in Example 7. The pressure amplitude in Examples 3 and 7 increases as the temperature increases. The pressure amplitude in Example 3 increases significantly with increasing temperature, particularly from around 800°C.

Figure 9 is a graph showing the relationship between the strength of self-excited vibration (magnitude of pressure amplitude) and the amount of heat transport in Examples 3 and 7. The black circles represent Example 3. The open triangles represent Example 7. Example 3 has a larger amount of heat transport per pressure amplitude than Example 7. It is believed that due to the difference in the relative position of the heat accumulator described above, Example 3 is able to achieve a larger amount of heat transport with a smaller pressure amplitude.

FIG. 10 is a graph showing the relationship between the pressure of the working fluid and the amount of heat transport in the heat transport device 1 of Example 7, measured in a preliminary experiment.

From the relationship between the pressure of the working fluid and the amount of heat transport shown in Figure 10, the amount of heat transport in the heat transport device 1 of Example 7 increases significantly when the pressure of the enclosed air, which is the working fluid, is between 0.1 MPaG (equivalent to approximately 0.2 MPa) and 0.2 MPaG (equivalent to approximately 0.3 MPa).

The low amount of heat transport when the pressure of the enclosed air is approximately 0.2 MPa or less is thought to be due to the fact that the generation of thermoacoustic self-oscillations has stopped or is in a state where the amount of generation is small. Therefore, it is thought that control to keep the pressure of the enclosed air at 0.2 MPa or less can be used as a control to reduce the amount of heat transport.

The high heat transport rate when the pressure of the enclosed air is approximately 0.3 MPa or higher is thought to be due to the active generation of thermoacoustic self-oscillations. Therefore, it is thought that control to increase the pressure of the enclosed air to 0.3 MPa or higher can be used to increase the heat transport rate.

In addition, in FIG. 10, as the pressure of the enclosed air increases from approximately 0.2 MPa to approximately 0.4 MPa, the heat transport amount increases in accordance with the pressure. Therefore, it is believed that it is possible to control the heat transport amount of the heat transport device 1 to be within a desired range by increasing or decreasing the pressure of the enclosed air.

The amount of heat transport in the heat transport device 1 of Example 7 increases as the pressure of the enclosed air, which is the working fluid, increases between 0.2 MPaG (equivalent to approximately 0.3 MPa) and 0.6 MPaG (equivalent to approximately 0.7 MPa). Therefore, it is considered that control to set the pressure of the enclosed air to 0.4 MPa or more and control to set the pressure of the enclosed air to 0.5 MPa or more are more effective as controls to increase the amount of heat transport.

In the pressurization experiment, the pressure of the enclosed air was increased from 0.1 MPa to 0.7 MPa over a period of approximately 40 seconds. In the pressurization experiment, the heat transport capacity, which was approximately 100 W before pressurization, rose to over 500 W approximately 80 seconds after pressurization was completed.

The pressurization experiment confirmed that the heat transport device 1 of this embodiment can be controlled to cause the heat accumulator 13 to generate self-excited thermoacoustic vibrations by increasing the pressure of the working fluid in response to a command to increase the amount of heat transport.

In the decompression experiment, the pressure of the sealed air was reduced from 0.7 MPa to 0.1 MPa over a period of approximately 45 seconds. In the decompression experiment, the heat transport capacity, which was over 500 W before the decompression, decreased to approximately 100 W approximately 30 seconds after the decompression was completed.

The decompression experiment confirmed that the heat transport device 1 of this embodiment can be controlled so that the heat accumulator 13 does not generate self-excited thermoacoustic vibrations by lowering the pressure of the working fluid in response to a command to reduce the amount of heat transport.

These controls make it possible to adjust the amount of heat transport without the risk of reducing the maintainability of the heat transport device, which would be the case if a drive source for moving the pressure adjustment means back and forth were provided inside the container, and without the risk of leaking the working fluid, which would be the case if a drive source for moving the adjustment means back and forth were provided outside the container.

It should be noted that within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, even if a person skilled in the art appropriately adds, deletes, or modifies the design of the above-mentioned embodiment, or adds, omits, or modifies processes, these modifications are also included within the scope of the present invention so long as they incorporate the essence of the present invention.

References
[Non-Patent Literature]
[Non-Patent Document 1] "New Acoustic Device Using Thermoacoustic Phenomenon", Tetsushi Biwa, JSME TED News letter 41 2-6, 2003

1 Heat transport device 11 Container 11P Pipe 11E1 First end 11E2 Second end 12 First heat exchanger 12a Heat receiving portion 13 Heat accumulator 13A Heat accumulator first bottom surface 13B Heat accumulator second bottom surface 13C Space 14 Second heat exchanger 15 Pressure control means 5 Heat transport device 51 Pipe 51E1 First end 51E2 Second end 52 First heat exchanger 53 First heat accumulator 53A First heat accumulator first bottom surface 53B First heat accumulator second bottom surface 54 Second heat exchanger 55 Third heat exchanger 56 Second heat accumulator 56A Second heat accumulator first bottom surface 56B Second heat accumulator second bottom surface 57 Fourth heat exchanger 58 Pressure control means F Furnace

Claims

A container is provided that can be disposed so as to span between a high-temperature heat source and an outside of the high-temperature heat source, and has a pipe therein, both ends of which can be substantially closed;
The inside of the pipe can be filled with a working fluid, and a first heat exchanger, a heat accumulator, and a second heat exchanger are arranged in this order from a first end portion to a second end portion of the pipe,
The first heat exchanger is disposed at a position capable of transferring heat of the high-temperature heat source to the working fluid,
The heat accumulator has a gap communicating between a periphery of the first heat exchanger of the pipe and a periphery of the second heat exchanger of the pipe, and is capable of generating thermoacoustic self-excited vibrations;
The pressure control means may be further provided to control the pressure of the working fluid.
The pressure control means is
a first pressure control unit capable of controlling a pressure of the working fluid so that the heat accumulator attenuates the self-excited oscillation in response to a command to reduce a heat transport amount;
a second pressure control unit capable of controlling a pressure of the working fluid so that the heat accumulator strengthens the self-excited oscillation in response to a command to increase a heat transport amount;
having
The second heat exchanger is capable of transferring heat of the working fluid to a heat medium outside the high-temperature heat source.
Heat transport device.
The heat transport device according to claim 1, wherein the working fluid includes air, the pressure control means is capable of controlling the pressure to be less than a first pressure in response to a command to reduce the amount of heat transport, and the first pressure is 0.2 MPa or less.
The heat transport device according to claim 2, wherein the working fluid includes air, the pressure control means is capable of controlling the pressure to be equal to or greater than a second pressure in response to a command to increase the amount of heat transport, and the second pressure is equal to or greater than 0.3 MPa.
A furnace comprising the heat transport device of claim 1 , the heat transport device being disposed so as to span between an interior of the furnace and an exterior of the furnace.