Heat transfer system

Abstract

To decrease environmental impact while increasing heat transfer performance.SOLUTION: A heat transfer system includes a first heat exchange portion arranged along a ground surface, a second heat exchange portion buried in the ground at a position deeper than the first heat exchange portion, a circulation flow path in which a working fluid composed of a temperature-sensitive magnetic fluid is sealed, and a magnet that is buried in the ground at a depth between the first heat exchange portion and the second heat exchange portion and applies a magnetic field to the working fluid to generate a propulsive force for circulating the working fluid in the circulation flow path.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to heat transfer systems. [Background technology]

[0002] Conventionally, heat transfer systems that transfer heat between the surface and the ground have been known. For example, Patent Document 1 discloses a configuration that melts snow on road surfaces by transferring underground heat to the surface using a heat pipe system. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-129619 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration described in Patent Document 1, heat is transferred using the latent heat of vaporization of the working fluid by a heat pipe system, which has the problem of lower heat transfer capacity compared to heat transfer systems using a liquid with a large specific heat.

[0005] In consideration of the above circumstances, an object of the present disclosure is to provide a heat transfer system that has a small environmental impact and can increase heat transfer capacity. [Means for solving the problem]

[0006] In order to solve the above problems, a heat transfer system according to one embodiment of the present disclosure includes a first heat exchange unit arranged along the ground surface and a second heat exchange unit buried in the ground at a deeper position than the first heat exchange unit, a circulation flow path in which a working fluid composed of a temperature-sensitive magnetic fluid is sealed, and a magnet buried in the ground at a depth between the first and second heat exchange units, which applies a magnetic field to the working fluid to generate a driving force that circulates the working fluid in the circulation flow path. [Effects of the Invention]

[0007] The present disclosure can reduce the environmental load and increase the heat transfer capacity. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a heat transfer system according to a first embodiment. [Figure 2] FIG. 10 is a diagram illustrating the embedding of a circulation flow path. [Figure 3] 1A and 1B are diagrams for explaining the principle of transfer of a working fluid by a magnet. [Figure 4] FIG. 1 is a diagram illustrating an example of the relationship between depth underground and temperature for each season. [Figure 5] FIG. 1 is a diagram showing an example of temperature changes over a one-year period at different depths underground. [Figure 6] FIG. 10 is a schematic diagram of a heat transfer system according to a second embodiment. [Figure 7] FIG. 4 is a diagram illustrating a heat transfer member. [Figure 8] FIG. 10 is a schematic diagram of a heat transfer system according to a third embodiment. [Figure 9] FIG. 10 is a schematic diagram of a heat transfer system according to a fourth embodiment. [Figure 10] 10 is an explanatory diagram of the operation of the heat transfer system according to the fourth embodiment. FIG. [Figure 11] FIG. 10 is a schematic diagram of a heat transfer system according to a fifth embodiment. [Figure 12] FIG. 10 is a schematic diagram of a heat transfer system according to a sixth embodiment. [Figure 13] FIG. 10 is an explanatory diagram of a magnet in Modification 1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings. The dimensions and scale of each part in the drawings may differ from those of the actual parts, and some parts are shown schematically to facilitate understanding. The scope of the present disclosure is not limited to these embodiments unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0010] 1. First embodiment 1-1. Overview of the heat transfer system 1 is a schematic diagram of a heat transfer system 100 according to a first embodiment. The heat transfer system 100 transfers heat between the ground surface GS and the underground GU. In this embodiment, heat from the underground GU is transferred to the ground surface GS, such as a road surface, to melt, melt snow, or prevent freezing on the ground surface GS.

[0011] The heat transfer system 100 includes a circulation flow path 10, a magnet 20, and a heat insulating material 30. Each part of the heat transfer system 100 will be outlined below with reference to FIG.

[0012] The circulation flow path 10 is a closed-loop conduit for circulating the working fluid FL. The working fluid FL is sealed in the circulation flow path 10. The working fluid FL is composed of a temperature-sensitive magnetic fluid. A temperature-sensitive magnetic fluid is a colloidal solution in which temperature-sensitive ferromagnetic particles are dispersed in a dispersion medium as a dispersoid, and exhibits the characteristic of decreasing magnetization as the temperature rises in the room temperature range. Therefore, a temperature difference along the circulation flow path 10 causes a difference in the magnetization characteristics of the working fluid FL. In the heat transfer system 100, the interaction between this difference in magnetization characteristics and the magnetic field from the magnet 20 generates a driving force that circulates the working fluid FL through the circulation flow path 10.

[0013] The ferromagnetic particles of the temperature-sensitive magnetic fluid are not particularly limited, but examples thereof include iron oxide particles such as γ-hematite (γ-Fe2O3) or magnetite, spinel ferrite (MFe2O4: M=Fe, Mn, Ni, Mn X Zn 1-XAmong these, one kind can be used alone or two or more kinds can be used in combination. Among them, manganese zinc ferrite (Mn X Zn 1-X Fe2O4) microparticles have a relatively large magnetization in the room temperature range, and the range of change in magnetization with temperature is large. In addition, they have the property that the Curie temperature can be adjusted by adjusting the composition, making them suitable as ferromagnetic microparticles for the working fluid FL.

[0014] The dispersion medium for the temperature-sensitive magnetic fluid is not particularly limited, but examples include water, polyhydric alcohols such as ethylene glycol and propylene glycol, alcohols such as ethanol, hydrocarbon oils such as kerosene and alkylnaphthalene, and fluorine-based oils such as purple fluoropolyether, and among these, one type can be used alone or two or more types can be used in combination.

[0015] In particular, it is preferable to use one or both of water and alcohol as the dispersion medium of the temperature-sensitive magnetic fluid, more preferably a mixture of water and alcohol, and even more preferably a mixture of water and polyhydric alcohol. Thus, the working fluid FL is preferably a water-based or alcohol-based fluid, and more preferably a polyhydric alcohol-based fluid. This allows the specific heat and thermal conductivity of the working fluid FL to be higher than in embodiments using oil-based fluids. As a result, the heat transfer efficiency by sensible heat can be improved. Furthermore, the latent heat of vaporization of the working fluid FL can be higher than in embodiments using oil-based fluids. As a result, the heat transfer efficiency by latent heat can also be improved. A water-based fluid is a fluid in which water accounts for 50 wt% or more of the dispersion medium, and includes embodiments in which the dispersion medium is composed solely of water, such as pure water, as well as embodiments in which the dispersion medium is a water solution or mixture. An alcohol-based fluid is a fluid in which alcohol accounts for 50 wt% or more of the dispersion medium, and includes embodiments in which the dispersion medium is composed solely of alcohol, as well as embodiments in which the dispersion medium is a solution or mixture of alcohol. An oil-based fluid is a fluid in which oil accounts for 50 wt% or more of the dispersion medium, including embodiments in which the dispersion medium is composed solely of oil as well as embodiments in which the dispersion medium is a solution or mixture of oil. A polyhydric alcohol-based fluid is a fluid in which polyhydric alcohol accounts for 50 wt% or more of the dispersion medium, including embodiments in which the dispersion medium is composed solely of polyhydric alcohol as well as embodiments in which the dispersion medium is a solution or mixture of polyhydric alcohol.

[0016] The circulation flow path 10 is formed, for example, using a tubular body. The inner diameter (diameter) of the tubular body is not particularly limited, but is, for example, 10 mm to 30 mm. The material of the tubular body is not particularly limited, but a resin material such as high-density polyethylene PE100, which has excellent flexibility and strength, is preferably used from the viewpoints of ease of handling during installation and durability after installation. The material of the tubular body is not limited to a resin material, and at least a portion of the tubular body may be formed of a metal such as stainless steel or aluminum. However, since a magnetic field from a magnet 20 must be applied to the working fluid FL in the drive unit 13 described below, the tubular body is formed of a non-magnetic material at least in the drive unit 13. The non-magnetic material is preferably a resin material such as polyphenylene sulfide (PPS) with excellent thermal conductivity, from the viewpoints of durability after installation and of suitably exhibiting the temperature-sensing effect of the working fluid FL in the drive unit 13 described below, and is particularly preferably a resin material with a thermal conductivity of 5 W / mK or more.

[0017] The circulation flow path 10 has a first heat exchange section 11, a second heat exchange section 12, and a drive section 13.

[0018] The first heat exchanger 11 is a part of the circulation flow path 10, and is arranged along the ground surface GS, and exchanges heat with the ground surface GS. The first heat exchanger 11 is arranged in a position where it can exchange heat with the ground surface GS, and is buried in a road surface structure, for example. In this embodiment, the first heat exchanger 11 releases heat toward the ground surface GS. This melts, melts, or prevents freezing on the ground surface GS.

[0019] In the example shown in Fig. 1, the first heat exchanger 11 has a serpentine shape. This allows the arrangement density of the first heat exchanger 11 to be uniform. The length of the first heat exchanger 11 is not particularly limited, but when used for snow melting, for example, it is preferably 25 m or less from the viewpoint of improving the efficiency of heat transfer. The shape of the first heat exchanger 11 is not limited to the example shown in Fig. 1 and can be any shape.

[0020] The second heat exchanger 12 is a part of the circulation flow path 10, and is buried in the underground GU at a deeper position than the first heat exchanger 11, and exchanges heat with the underground GU. The second heat exchanger 12 is disposed, for example, in a vertical hole extending from the ground surface GS toward the underground GU, as will be described in detail later with reference to FIG. 2. In this embodiment, the second heat exchanger 12 receives heat from the underground GU. This allows the temperature of the working fluid FL after heat exchange in the first heat exchanger 11 to be increased.

[0021] 1, the second heat exchanger 12 is generally U-shaped and folded back at the deepest position. This makes it relatively easy to install the second heat exchanger 12, and therefore the heat transfer system 100. The shape of the second heat exchanger 12 is not limited to the example shown in FIG. 1 and may be any shape. For example, the second heat exchanger 12 may have a shape that includes a portion that extends horizontally underground GU.

[0022] The driver 13 is a part of the circulation flow path 10 and serves to generate a driving force PA of the working fluid FL by the magnet 20. The driver 13 is disposed between the first heat exchanger 11 and the second heat exchanger 12. The driver 13 extends in a direction having a depth component. In the example shown in FIG. 1, the driver 13 extends in the depth direction, i.e., the vertical direction. As will be described in detail later, the driver 13 is disposed at a depth position that can generate a temperature difference in the working fluid FL within the driver 13 along the circulation flow path 10. The shape and orientation of the driver 13 are not limited to the example shown in FIG. 1, and may be any shape that can generate a driving force PA. For example, the driver 13 may extend in a direction inclined with respect to the depth direction, or may have a shape with a bent or curved portion.

[0023] The magnet 20 is a structure that applies a magnetic field MF to the working fluid FL in the drive unit 13. The magnetic field MF generates a driving force PA that circulates the working fluid FL through the circulation flow path 10. The magnet 20 is disposed at a depth corresponding to the depth of the drive unit 13. In other words, the magnet 20 is buried in the ground GU at a depth between the first heat exchange unit 11 and the second heat exchange unit 12.

[0024] The magnet 20 may be an electromagnet as long as it can apply a magnetic field MF that generates a driving force PA to the working fluid FL, but is preferably a permanent magnet. This allows the magnetic field MF that generates the driving force PA that circulates the working fluid FL through the circulation flow path 10 to be applied to the working fluid FL without using electric power. Furthermore, compared to embodiments that use electromagnets, the configuration of the heat transfer system 100 can be simplified. Even if the magnet 20 is an electromagnet, the environmental impact can be reduced by driving the electromagnet with electric power obtained by generating electricity from renewable energy sources such as geothermal, wind, or solar power.

[0025] The permanent magnet used for magnet 20 is not particularly limited, and examples include neodymium magnets, samarium-cobalt magnets, and ferrite magnets. However, neodymium magnets are preferred because of their ability to generate a large magnetic force. The shape of the permanent magnet is not particularly limited, and may be cylindrical, semi-cylindrical, cubic, rectangular, or other similar shapes, as long as it can apply a magnetic field MF that generates a driving force PA to the working fluid FL. Furthermore, magnet 20 may be configured by combining multiple permanent magnets. For example, as shown in Modification 1, magnet 20 may be configured by one or more pairs of permanent magnets facing each other across drive unit 13, or by combining magnet 20 with a yoke, or by a permanent magnet located on only one side of drive unit 13.

[0026] In the heat transfer system 100 outlined above, a magnet 20 buried in the ground GU at a depth between the first heat exchange unit 11 and the second heat exchange unit 12 applies a magnetic field MF to the working fluid FL, which generates a driving force PA that circulates the working fluid FL through the circulation flow path 10. This makes it possible to circulate the working fluid FL through the circulation flow path 10 using natural energy without emitting CO2. Furthermore, this system has the advantage of having a greater heat transfer force than the heat pipe system.

[0027] The heat insulating material 30 is an insulating member that covers the periphery of the circulation flow path 10 above the magnet 20, i.e., between the magnet 20 and the ground surface GS, and is made of, for example, a resin foam such as urethane. This makes it possible to increase the temperature difference of the working fluid FL in the drive unit 13 in the direction along the circulation flow path 10 in an embodiment where snow melting, snow removal, or anti-freezing is performed on the ground surface GS, as in this embodiment. In the illustration, the heat insulating material 30 is provided over the entire area between the magnet 20 and the ground surface GS. Note that the length of the heat insulating material 30 is not limited to the example shown in the figure, and may be shorter than the distance between the magnet 20 and the ground surface GS, for example. Furthermore, the heat insulating material 30 may be provided as needed or may be omitted.

[0028] 1-2. Burying the circulation channel FIG. 2 is a diagram illustrating the burying of the circulation flow path 10. FIG. 2 shows a portion of the circulation flow path 10 near the drive unit 13. As shown in FIG. 2, the portion of the circulation flow path 10 excluding the first heat exchange unit 11 is disposed in a vertical hole H extending from the ground surface GS toward the underground GU. This portion includes the second heat exchange unit 12, a pipe connected to one end of the second heat exchange unit 12, and a pipe connected to the other end of the second heat exchange unit 12. The vertical hole H is a hole for disposing the pipes that constitute the circulation flow path 10. In the example shown in FIG. 2, the vertical hole H extends parallel to the depth direction. Note that the vertical hole H may have a portion that extends in a direction that is inclined relative to the depth direction.

[0029] It is preferable to fill the vertical hole H with thermally conductive clay or silica sand. This allows the periphery of the second heat exchange section 12 to be covered with thermally conductive clay or silica sand. As a result, heat exchange in the second heat exchange section 12 can be carried out efficiently. Furthermore, in an embodiment using silica sand, the vertical hole H can be filled so as to cover the periphery of the second heat exchange section 12 simply by pouring the silica sand into the vertical hole H after excavating the vertical hole H. This has the advantage of keeping construction costs low.

[0030] The magnets 20 are arranged along the periphery of the driver 13. As described above, the driver 13 extends in a direction having a depth component, which has the advantage of easily generating a temperature difference in the working fluid FL in the driver 13 in the depth direction. Furthermore, because the magnets 20 are arranged along the periphery of the driver 13, the application of a magnetic field MF from the magnets 20 to the working fluid FL can effectively generate a driving force PA that circulates the working fluid FL through the circulation flow path 10. Note that "arranged along the periphery of the driver 13" means facing at least a portion of the outer circumferential surface of the driver 13 in the circumferential direction, and includes, for example, a configuration in which the magnets surround the entire outer circumferential surface of the driver 13, a configuration in which the magnets face the outer circumferential surface of the driver 13, and a configuration in which the magnets are arranged facing each other with the driver 13 in between.

[0031] The length of the magnet 20 along the longitudinal direction of the drive unit 13 is not particularly limited, but is, for example, 10 cm to 1 m. On the other hand, if the length of the magnet 20 is too short, it may be difficult to generate a magnetic field MF of sufficient strength, depending on the length of the circulation flow path 10, etc. On the other hand, if the length of the magnet 20 is too long, the distance between the part of the working fluid FL where the magnetized body force is large and the maximum of the magnetic field MF becomes too large, as will be described later, and the propulsive force PA tends to decrease.

[0032] 1-3. Principles of working fluid transfer Fig. 3 is a diagram illustrating the principle of transfer of working fluid FL by magnet 20. Fig. 3 shows a cross-sectional view of the magnet 20 and a portion of circulation flow path 10 near drive unit 13. Fig. 3 also shows the relationship between the distribution of the magnetic field generated by magnet 20 in the direction in which drive unit 13 extends and the distribution of the magnetized body force of working fluid FL. For ease of explanation, Fig. 3 shows the working fluid FL with a density that indicates its temperature distribution, with the density increasing as the temperature increases.

[0033] In the example shown in FIG. 3 , a spacer 14 is disposed between the drive unit 13 and the magnet 20. The spacer 14 is a tubular body that fills the gap between the drive unit 13 and the magnet 20. From the viewpoints of durability after installation and favorably exhibiting the temperature-sensing effect of the working fluid FL in the drive unit 13 (described later), the spacer 14 is preferably made of a resin material with excellent thermal conductivity, such as polyphenylene sulfide (PPS), high-density polyethylene, or phenolic resin. A resin material with a thermal conductivity of 5 W / mK or higher is particularly preferable. The material of the spacer 14 is not limited to resin and may be, for example, ceramic or nonmagnetic metal. The spacer 14 may also be integral with the drive unit 13. Furthermore, the spacer 14 may be provided as needed or omitted. For example, when the spacer 14 is integral with the drive unit 13 or omitted, the drive unit 13 is made of a tube having joints at both ends for connection to other parts of the circulation flow path 10. Like the spacer 14, the tube is preferably made of a resin material with excellent thermal conductivity such as polyphenylene sulfide (PPS), high density polyethylene, or phenolic resin, and is particularly preferably made of a resin material with a thermal conductivity of 5 W / mK or more.

[0034] The magnetic field MF from the magnet 20 reaches a maximum near the center of the drive unit 13 in the extension direction. Meanwhile, the magnetized body force of the working fluid FL in the drive unit 13 has a gradient due to the temperature difference in the extension direction of the drive unit 13. In the example shown in FIG. 3, the temperature at the bottom of FIG. 3 is higher than the temperature at the top of FIG. 3, so the magnetized body force of the working fluid FL in the drive unit 13 decreases from the top to the bottom of FIG. 3. Under these conditions, a driving force PA acts on the working fluid FL such that the portion of the working fluid FL where the magnetized body force is large approaches the maximum of the magnetic field MF. Note that when the temperature at the bottom of FIG. 3 is higher than the temperature at the top of FIG. 3, a driving force PB is generated in the opposite direction to the driving force PA, as will be described in detail in the fourth embodiment below.

[0035] As described above, since the working fluid FL is made of a temperature-sensitive magnetic fluid, when a temperature difference occurs in the working fluid FL in a direction along the circulation flow path 10, a difference in the magnetization characteristics of the working fluid FL occurs in a direction along the circulation flow path 10. The driving force PA is generated by the interaction between this difference in magnetization characteristics and the magnetic field MF from the magnet 20. To generate the driving force PA, the magnet 20 must be positioned so that the magnetic field MF acts on the position of the gradient of the magnetized body force of the working fluid FL as described above, in other words, the temperature position that generates this gradient.

[0036] 1-4. Second heat exchange section and magnet arrangement FIG. 4 shows an example of the relationship between the depth of the underground GU and the temperature by season. FIG. 5 shows an example of the change in temperature at each underground GU depth over a year. In FIG. 4, the temperature at the underground GU in summer is shown by a dashed line, the temperature at the underground GU in winter is shown by a solid line, the temperature at the underground GU in spring is shown by a dashed double-dashed line, and the temperature at the underground GU in autumn is shown by a dashed line in a certain region of Japan. FIG. 5 shows the change in underground temperature over a year in another region of Japan. In FIG. 5, the dashed double-dashed line indicates the temperature at the surface, i.e., at a depth of 0 m, the temperature at a depth of 1 m, the dashed line indicates the temperature at a depth of 2 m, the solid line indicates the temperature at a depth of 3 m, and the double line indicates the temperature at a depth of 5 m.

[0037] As shown in Figure 4, the temperature remains almost constant at depths of 10 m or more in the underground GU in spring, summer, autumn, and winter. In contrast, in summer, the temperature drops sharply from the surface GS to a depth of approximately 5 m. On the other hand, in winter, the temperature rises sharply from the surface GS to a depth of approximately 5 m.

[0038] As shown in Figure 4, the temperature difference between the surface GS and a depth of 1 m is approximately 4°C in both summer and winter. The underground GU is cooler in summer and warmer in winter, near a depth of 5 m. The temperature is lowest in summer at the underground GU near a depth of 5 m. In winter, the temperature is highest at the underground GU near a depth of 5 m.

[0039] In this embodiment, in winter, the magnet 20 is placed at a depth of 3 m to 6 m underground GU to preferably generate the aforementioned temperature difference in the working fluid FL in the drive unit 13. This makes it possible to increase the temperature difference in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is lower than the temperature of the underground GU. Note that the position of the magnet 20 refers to the position of the center of the magnet 20.

[0040] The second heat exchanger 12 is disposed at a depth of 5 m or more underground GU, preferably at a depth of 10 m or more, and more preferably at a depth of 10 m to 20 m. This allows for optimal heat exchange in the second heat exchanger 12. On the other hand, if the second heat exchanger 12 is disposed too shallow, it is difficult to adequately perform heat exchange in the second heat exchanger 12 and also difficult to appropriately generate the temperature difference described above in the working fluid FL within the drive unit 13. On the other hand, if the second heat exchanger 12 is disposed too deep, the installation cost of the circulation flow path 10 increases and it tends to be difficult to circulate the working fluid FL through the circulation flow path 10 using the driving force PA. The position of the second heat exchanger 12 refers to the bottom end of the second heat exchanger 12, i.e., its deepest position.

[0041] As described above, the heat transfer system 100 can reduce the environmental load and increase the heat transfer capacity. In this embodiment, when melting, extinguishing, or preventing freezing on the ground surface GS, the environmental load is reduced and the heat transfer capacity is increased.

[0042] 2. Second embodiment A second embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the above embodiment, the reference numerals used in the description of the above embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0043] 6 is a schematic diagram of a heat transfer system 100A according to a second embodiment. The heat transfer system 100A has the same configuration as the heat transfer system 100 of the first embodiment, except that it includes a heat transfer member 15 instead of the spacer 14 of the first embodiment.

[0044] The heat transfer member 15 is a thermally conductive member that transfers heat from a position deeper than the drive unit 13 to the drive unit 13. This allows a favorable temperature difference to be generated in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is lower than the temperature of the underground GU. For example, it is possible to increase the temperature difference in the depth direction of the working fluid FL in the drive unit 13 and reduce the distance between the maximum of the magnetic field MF of the magnet 20 and the part where the magnetized body force of the working fluid FL changes. As a result, the propulsion force PA can be increased.

[0045] FIG. 7 is a diagram illustrating the heat transfer member 15. As shown in FIG. 7, the heat transfer member 15 includes a plurality of heat collection fins 15a and a spacer 15b. The spacer 15b has a configuration similar to that of the spacer 14 of the first embodiment. However, the spacer 15b has a portion that protrudes deeply from the magnet 20. The plurality of heat collection fins 15a are heat-conductive plate-like members that protrude from the outer peripheral surface of the spacer 15b. The material of the heat collection fins 15a is not particularly limited as long as it has thermal conductivity. However, like the spacer 15b, a resin material such as polyphenylene sulfide (PPS) with excellent thermal conductivity is preferable, and a resin material with a thermal conductivity of 5 W / mK or higher is particularly preferable. The material of the heat transfer member 15 is not limited to resin and may be, for example, ceramics or metal. The heat transfer member 15 may also be integrally formed with the drive unit 13.

[0046] The heat transfer system 100A of the second embodiment described above also has a small environmental impact and can increase heat transfer power. In this embodiment, as described above, the heat transfer member 15 has the heat collection fins 15a, so that heat can be efficiently transferred to the drive unit 13 from a position deeper than the drive unit 13. As a result, a temperature difference in the depth direction of the working fluid FL in the drive unit 13 can be suitably generated.

[0047] 3. Third embodiment A third embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the above-described embodiment, the reference numerals used in the description of the above-described embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0048] 8 is a schematic diagram of a heat transfer system 100B according to a third embodiment. The heat transfer system 100B has the same configuration as the heat transfer system 100 of the first embodiment, except that a heat transfer member 16 is added.

[0049] The heat transfer member 16 is a thermally conductive member that transfers heat from a position deeper than the drive unit 13 to the drive unit 13. This allows a favorable temperature difference to be generated in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is lower than the temperature of the underground GU. For example, it is possible to increase the temperature difference in the depth direction of the working fluid FL in the drive unit 13 and reduce the distance between the maximum of the magnetic field MF of the magnet 20 and the part where the magnetized body force of the working fluid FL changes. As a result, the propulsion force PA can be increased.

[0050] In the example shown in FIG. 8, the heat transfer member 16 is composed of a plurality of heat pipes 16a. Each heat pipe 16a is not particularly limited, and various known heat pipes can be used, for example. Each heat pipe 16a extends in a direction having a depth component, and has one end connected to the drive unit 13 and the other end located deeper than the one end. In the example shown in FIG. 8, each heat pipe 16a extends parallel to the depth direction. Note that the number, shape, and orientation of the heat pipes 16a are not limited to those shown in FIG. 8. For example, the heat pipes 16a may have a bent or curved portion, or may be arranged to extend in a direction inclined relative to the depth direction.

[0051] The heat transfer system 100B of the third embodiment described above also has a small environmental impact and can increase heat transfer power. In this embodiment, as described above, the heat transfer member 16 has the heat pipe 16a, so that heat can be efficiently transferred to the drive unit 13 from a position deeper than the drive unit 13. As a result, a temperature difference in the depth direction of the working fluid FL in the drive unit 13 can be suitably generated.

[0052] 4. Fourth embodiment A fourth embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the above-described embodiment, the reference numerals used in the description of the above-described embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0053] Fig. 9 is a schematic diagram of a heat transfer system 100C according to a fourth embodiment. Fig. 10 is an explanatory diagram of the operation of the heat transfer system 100C according to the fourth embodiment. Fig. 9 shows the state of the heat transfer system 100C in winter. Fig. 10 shows the state of the heat transfer system 100C in summer.

[0054] The heat transfer system 100C is a system that can take measures in both summer and winter. In winter, the heat transfer system 100C, like the first embodiment, transfers heat from underground GU to ground surface GS, such as a road surface, to melt, melt, or prevent snow from freezing on the ground surface GS. On the other hand, in summer, the heat transfer system 100C lowers the temperature of the ground surface GS by transferring heat from the ground surface GS to underground GU. This allows for measures against the heat island phenomenon.

[0055] The heat transfer system 100C is configured similarly to the heat transfer system 100 of the first embodiment, except that the drive unit 13 is disposed differently and a heat transfer member 17 is added.

[0056] In this embodiment, the magnet 20 is placed at a depth of 0.25 m to 3 m underground GU. This increases the temperature difference in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is higher than the temperature of the underground GU. Therefore, in summer, the heat transfer system 100C generates a driving force PB in the opposite direction to the driving force PA by the magnet 20 applying a magnetic field MF to the working fluid FL in the drive unit 13, as shown in FIG. 10 .

[0057] As mentioned above, the relationship between depth and temperature difference is almost the same in summer and winter, but the position of the magnet 20 in this embodiment is shallower than the positions of the magnet 20 in the first to third embodiments. The reason for this is to reduce the effect of the warm working fluid FL tending to remain in the upper part and therefore being less likely to move downward.

[0058] However, if the magnet 20 is simply positioned at a shallow location, it is difficult to increase the temperature difference in the working fluid FL in the drive unit 13 in the depth direction in winter.

[0059] Therefore, the heat transfer system 100C includes a heat transfer member 17. The heat transfer member 17 transfers heat to the drive unit 13 from a position deeper than the drive unit 13. This allows a favorable temperature difference to be generated in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is lower than the temperature of the underground GU. For example, the temperature difference in the depth direction of the working fluid FL in the drive unit 13 can be increased, and the distance between the maximum of the magnetic field MF of the magnet 20 and the part where the magnetized body force of the working fluid FL changes can be reduced. As a result, the propulsion force PA can be increased.

[0060] Here, the lower end of the heat transfer member 17 is placed at a depth of 3 m to 6 m inclusive underground GU. This makes it possible to preferably generate a temperature difference in the depth direction of the working fluid FL in the drive unit 13 in winter, even if the magnet 20 is placed at a depth of 0.25 m to 3 m inclusive underground GU. As a result, the magnet 20 applies a magnetic field MF to the working fluid FL in the drive unit 13, thereby generating a propulsive force PA.

[0061] In the example shown in FIGS. 9 and 10 , the heat transfer member 17 is composed of a plurality of heat pipes 17 a. Like the heat pipe 16 a of the third embodiment, each heat pipe 17 a is not particularly limited, and various known heat pipes can be used. Each heat pipe 17 a extends in a direction having a depth component, and has one end connected to the drive unit 13 and the other end located deeper than the one end. In the example shown in FIGS. 9 and 10 , each heat pipe 17 a extends parallel to the depth direction. Note that the number, shape, and orientation of the heat pipes 16 a are not limited to those shown in FIG. 8 . For example, the heat pipe 16 a may have a bent or curved portion, or may be arranged to extend in a direction inclined relative to the depth direction.

[0062] In this way, since the heat transfer member 17 has the heat pipe 17a, heat can be efficiently transferred from a position deeper than the drive unit 13 to the drive unit 13. As a result, a temperature difference in the working fluid FL in the drive unit 13 can be suitably generated in the depth direction.

[0063] The heat transfer system 100C of the fourth embodiment described above also has a small environmental impact and can increase heat transfer power. In this embodiment, as described above, the magnet 20 is disposed at a depth of 0.25 m to 3 m below the ground GU. This increases the temperature difference in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is higher than the temperature of the underground GU. Furthermore, the heat transfer member 17 transfers heat to the drive unit 13 from a position deeper than the drive unit 13. This increases the temperature difference in the depth direction of the working fluid FL in the drive unit 13, even when the temperature of the ground surface GS is lower than the temperature of the underground GU.

[0064] 5. Fifth embodiment A fifth embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the above-described embodiment, the reference numerals used in the description of the above-described embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0065] 11 is a schematic diagram of a heat transfer system 100D according to a fifth embodiment. The heat transfer system 100D is a system for combating the heat island effect, and in summer, lowers the temperature of the ground surface GS by transferring heat from the ground GS to the underground GU.

[0066] The heat transfer system 100D is configured similarly to the heat transfer system 100 of the first embodiment, except for the arrangement of the magnets 20. That is, the heat transfer system 100D is configured similarly to the heat transfer system 100C of the fourth embodiment, except for the omission of the heat transfer member 17.

[0067] The heat transfer system 100D of the fifth embodiment described above also has a small environmental impact and can increase heat transfer capacity. This embodiment has the advantage of being able to reduce the cost of the system when only heat island countermeasures are required.

[0068] 6. Sixth embodiment A sixth embodiment of the present disclosure will be described below. In the following exemplary embodiment, for elements whose actions and functions are similar to those of the above-described embodiment, the reference numerals used in the description of the above-described embodiment will be used, and detailed descriptions of each element will be omitted as appropriate.

[0069] 12 is a schematic diagram of a heat transfer system 100E according to a sixth embodiment. The heat transfer system 100E is a system for combating the heat island phenomenon, and in summer, lowers the temperature of the ground surface GS by transferring heat from the ground GS to the underground GU.

[0070] The heat transfer system 100E has the same configuration as the heat transfer system 100C of the fourth embodiment, except that it includes a heat transfer member 18 instead of the heat transfer member 17 of the fourth embodiment. That is, the heat transfer system 100E has the same configuration as the heat transfer system 100D of the fifth embodiment, except that it includes the heat transfer member 18.

[0071] The heat transfer member 18 is a thermally conductive member that transfers heat from a position shallower than the drive unit 13 to the drive unit 13. This allows for a favorable temperature difference in the depth direction of the working fluid FL in the drive unit 13 when the temperature of the ground surface GS is higher than the temperature of the underground GU. For example, it is possible to increase the temperature difference in the depth direction of the working fluid FL in the drive unit 13 and reduce the distance between the maximum of the magnetic field MF of the magnet 20 and the part where the magnetized body force of the working fluid FL changes. As a result, the propulsion force PA can be increased.

[0072] The heat transfer member 18 has a configuration similar to the heat transfer member 15 of the second embodiment and includes a plurality of heat collection fins 18a. Here, the heat transfer member 18 has a portion that protrudes shallowly from the magnet 20, and a plurality of heat collection fins 18a are provided on this portion. The material of the heat collection fins 18a may be any material that has thermal conductivity, but is not particularly limited. For example, a resin material such as polyphenylene sulfide (PPS) that has excellent thermal conductivity is preferable, and a resin material with a thermal conductivity of 5 W / mK or more is particularly preferable. The material of the heat transfer member 18 is not limited to resin, and may be, for example, ceramics or metal. The heat transfer member 18 may also be formed integrally with the drive unit 13.

[0073] In this way, by having the heat collecting fins 18a, the heat transfer member 18 can efficiently transfer heat to the drive unit 13 from a position shallower than the drive unit 13.

[0074] The heat transfer system 100E of the sixth embodiment described above also has a small environmental impact and can increase heat transfer power. In this embodiment, as described above, the heat transfer member 18 transfers heat to the drive unit 13 from a position shallower than the drive unit 13, which reduces the tendency of the warm working fluid FL to remain in the upper part and thus to have difficulty in moving downward. As a result, even if the temperature of the ground surface GS is higher than the temperature of the underground GU, the temperature difference of the working fluid FL in the drive unit 13 in the depth direction can be increased.

[0075] 7. Variations The above-described embodiments can be modified in various ways. Specific modifications that can be applied to the above-described embodiments are exemplified below. Two or more embodiments arbitrarily selected from the following examples can be combined as appropriate within the scope of not mutually contradictory.

[0076] 7-1. Variation 1 13 is an explanatory diagram of magnet 20A in Modification 1. Modification 1 is similar to the first embodiment described above, except that magnet 20A is used instead of magnet 20 and a pair of yokes 40 is added. Note that Modification 1 may be applied to any of the second to sixth embodiments.

[0077] The magnet 20A has a pair of permanent magnets 21 and a pair of permanent magnets 22.

[0078] The pair of permanent magnets 21 are arranged so that their south poles face each other across the driving unit 13. That is, of the pair of permanent magnets 21, one permanent magnet 21 is arranged on one side of the driving unit 13 so that its south pole faces the driving unit 13, and the other permanent magnet 21 is arranged on the other side of the driving unit 13 so that its south pole faces the driving unit 13.

[0079] The pair of permanent magnets 22 are disposed below the pair of permanent magnets 21 so that their north poles face each other across the driving unit 13. That is, of the pair of permanent magnets 22, one permanent magnet 22 is disposed on one side of the driving unit 13 so that its north pole faces the driving unit 13, and the other permanent magnet 22 is disposed on the other side of the driving unit 13 so that its north pole faces the driving unit 13. Note that while FIG. 13 illustrates an example in which the pair of permanent magnets 21 and 22 are in contact with each other, the pair of permanent magnets 21 and 22 may also be disposed with a gap between them.

[0080] The pair of yokes 40 are components that guide the magnetic field from the pair of permanent magnets 21 and the pair of permanent magnets 22 to the working fluid FL in the drive unit 13, and are made of, for example, soft iron. Of the pair of yokes 40, one yoke 40 is arranged on one side of the drive unit 13, and the other yoke 40 is arranged on the other side of the drive unit 13.

[0081] Between one yoke 40 and the driving unit 13, a pair of permanent magnets 21 and 22 is disposed on one side of the driving unit 13 so that the north pole of the permanent magnet 21 faces the yoke 40, and the south pole of the permanent magnet 22 faces the yoke 40. Between the other yoke 40 and the driving unit 13, a pair of permanent magnets 21 and 22 is disposed on the other side of the driving unit 13 so that the north pole of the permanent magnet 21 faces the yoke 40, and the south pole of the permanent magnet 22 faces the yoke 40.

[0082] Such a pair of yokes 40 guides the magnetic field MF from the magnet 20A to the driving unit 13 so as to increase the attractive force at the driving unit 13. This makes it possible to efficiently increase the magnetic field MF at the driving unit 13. In other words, it is possible to form a local maximum of the magnetic field MF at the driving unit 13 so as to increase the propulsive force PA or the propulsive force PB.

[0083] However, the orientations of the permanent magnets 21, 22 are not limited to the example shown in FIG. 13 and may be changed as appropriate. For example, a pair of permanent magnets 21 may be arranged so that the south pole of one permanent magnet 21 faces the drive unit 13 and the north pole of the other permanent magnet 21 faces the drive unit 13. Similarly, a pair of permanent magnets 22 may be arranged so that the south pole of one permanent magnet 22 faces the drive unit 13 and the north pole of the other permanent magnet 22 faces the drive unit 13. Furthermore, each of the pair of permanent magnets 21 may be magnetized along the length direction of the drive unit 13. In this case, the magnetization directions of the pair of permanent magnets 21 may be the same or opposite directions. Similarly, each of the pair of permanent magnets 22 may be magnetized along the length direction of the drive unit 13. In this case, the magnetization directions of the pair of permanent magnets 22 may be the same or opposite directions.

[0084] Furthermore, one of the pair of permanent magnets 21, 22 and yoke 40 arranged on one side of drive unit 13 and the pair of permanent magnets 21, 22 and yoke 40 arranged on the other side of drive unit 13 may be omitted. Furthermore, three or more pairs of permanent magnets 21, 22 and yoke 40 may be used.

[0085] 13 , the arrangement, shape, and number of the yokes 40 are not limited to those shown in FIG. 13 , and may be changed as appropriate. For example, when the magnetization direction of the permanent magnets 21 and 22 is along the longitudinal direction of the drive unit 13, and the north pole of one of the pair of permanent magnets 21 and 22 faces the south pole of the other permanent magnet, the yoke 40 may be formed of a pair of yokes arranged to sandwich the pair of permanent magnets 21 and 22 in the longitudinal direction. When the magnetization direction of the permanent magnets 21 and 22 is along the longitudinal direction of the drive unit 13, and the south poles or north poles of the pair of permanent magnets 21 and 22 face each other, the yoke 40 may be formed of a pair of yokes arranged to sandwich the pair of permanent magnets 21 and 22 in the longitudinal direction, and a yoke arranged between the permanent magnets 21 and 22.

[0086] The yoke 40 may be used as needed or may be omitted.

[0087] 7-2. Variation 2 In the above-described embodiments, except for the fourth embodiment, an example is given in which one of snow melting and heat island countermeasures is performed, but this is not limited to this example, and for example, the position of the magnet 20, etc. may be variable so that both snow melting and heat island countermeasures can be performed.

[0088] 7-3. Variation 3 It is also possible to combine two or more of the above-described embodiments. For example, the configuration inside the underground GU may be configured to switch between two systems, one of the configurations of the first to third embodiments and the configuration of the fifth or sixth embodiment, depending on the season.

[0089] 8. Notes For example, the following aspects can be understood from the above embodiment and modified examples.

[0090] (Appendix 1) A first aspect, which is a preferred example of the heat transfer system of the present disclosure, has a first heat exchange unit arranged along the ground surface and a second heat exchange unit buried in the ground at a position deeper than the first heat exchange unit, and is equipped with a circulation flow path in which a working fluid composed of a temperature-sensitive magnetic fluid is sealed, and a magnet buried in the ground at a depth between the first heat exchange unit and the second heat exchange unit, which applies a magnetic field to the working fluid to generate a driving force that circulates the working fluid in the circulation flow path.

[0091] In the above-described embodiment, a magnet buried underground at a depth between the first and second heat exchange units applies a magnetic field to the working fluid, generating a driving force for circulating the working fluid through the circulation flow path. This allows the working fluid to be circulated through the circulation flow path using natural energy without emitting CO2. Furthermore, compared to the heat pipe method, this method has the advantage of providing a greater heat transfer capacity. Here, because the working fluid is a temperature-sensitive magnetic fluid, a temperature difference in the working fluid along the circulation flow path causes a difference in the magnetic properties of the working fluid along the circulation flow path. This driving force is generated by the interaction between the difference in magnetic properties and the magnetic field from the magnet. As a result, the environmental impact is small and the heat transfer capacity can be increased.

[0092] (Supplementary Note 2) In a second aspect, which is a preferred example of the first aspect, the circulation flow path has a drive unit for generating the propulsive force, the drive unit extending in the depth direction, and the magnets arranged along the periphery of the drive unit. In the above aspect, since the drive unit extends in a direction having a depth component, there is an advantage in that a temperature difference in the working fluid in the drive unit can be easily generated in the depth direction. Furthermore, since the magnets are arranged along the periphery of the drive unit, application of a magnetic field from the magnet to the working fluid can be suitably generated to generate a propulsive force that circulates the working fluid in the circulation flow path.

[0093] (Supplementary Note 3) In a third aspect, which is a preferred example of the first or second aspect, the second heat exchanger is placed at a depth of 5 m or more underground. In this aspect, heat exchange in the second heat exchanger can be performed favorably.

[0094] (Note 4) In a fourth aspect, which is a preferred example of any of the first to third aspects, the magnet is placed at a depth of 3 m to 6 m underground. In this aspect, when the temperature of the earth's surface is lower than the temperature underground, the temperature difference in the depth direction of the working fluid in the drive unit can be increased.

[0095] (Supplementary Note 5) In the fifth aspect, which is a preferred example of the fourth aspect, a heat transfer member is further provided that transfers heat to the drive unit from a position deeper than the drive unit. In the above aspect, when the temperature of the ground surface is lower than the temperature underground, a temperature difference in the depth direction of the working fluid in the drive unit can be suitably generated.

[0096] (Supplementary Note 6) In a sixth aspect which is a preferred example of the fifth aspect, the heat transfer member has a heat pipe. In the above aspect, heat can be efficiently transferred to the drive unit from a position deeper than the drive unit.

[0097] (Supplementary Note 7) In a seventh aspect which is a preferred example of the fifth aspect, the heat transfer member has heat collecting fins. In the above aspect, heat can be efficiently transferred to the drive unit from a position deeper than the drive unit.

[0098] (Appendix 8) In an eighth aspect, which is a preferred example of any of the first to third aspects, the magnet is placed at a depth of 0.25 m to 3 m underground. In this aspect, when the temperature of the earth's surface is higher than the temperature underground, the temperature difference in the depth direction of the working fluid in the drive unit can be increased.

[0099] (Supplementary Note 9) In a ninth aspect, which is a preferred example of the eighth aspect, a heat transfer member is further provided that transfers heat to the drive unit from a position deeper than the drive unit. In the above aspect, when the temperature of the ground surface is lower than the temperature underground, a temperature difference in the depth direction of the working fluid in the drive unit can be suitably generated.

[0100] (Supplementary Note 10) In a tenth aspect which is a preferred example of the ninth aspect, the heat transfer member has a heat pipe. In the above aspect, heat can be efficiently transferred to the drive unit from a position deeper than the drive unit.

[0101] (Supplementary Note 11) In the eleventh aspect, which is a preferred example of the eighth aspect, a heat transfer member that transfers heat to the drive unit from a position shallower than the drive unit is further provided. In the above aspect, when the temperature of the ground surface is higher than the temperature underground, the temperature difference in the working fluid in the drive unit can be increased in the depth direction.

[0102] (Supplementary Note 12) In a twelfth aspect which is a preferred example of the eleventh aspect, the heat transfer member has a heat collecting fin. In the above aspect, heat can be efficiently transferred to the drive unit from a position shallower than the drive unit.

[0103] (Appendix 13) In a thirteenth aspect, which is a preferred example of any of the first to twelfth aspects, the second heat exchanger is surrounded by a layer of thermally conductive clay or silica sand. In the above aspects, heat exchange in the second heat exchanger can be carried out efficiently. In addition, in the aspect using silica sand, the vertical hole in which the tubular body constituting the circulation flow path is to be placed can be filled with silica sand so as to cover the second heat exchanger. This has the advantage of keeping construction costs low.

[0104] (Supplementary Note 14) In a fourteenth aspect which is a preferred example of any one of the first to thirteenth aspects, the magnet is a permanent magnet. In the above aspect, a magnetic field that generates a driving force for circulating the working fluid in the circulation flow path can be applied to the working fluid without using electric power.

[0105] (Supplementary Note 15) In a fifteenth aspect, which is a preferred example of any one of the first to fourteenth aspects, a yoke is further provided for guiding the magnetic field from the magnet to the driving unit. In the above aspect, the magnetic field in the driving unit can be efficiently increased.

[0106] (Supplementary Note 16) In a sixteenth aspect, which is a preferred example of any of the first to fifteenth aspects, the working fluid is a water-based or alcohol-based fluid. In the above aspects, the specific heat and thermal conductivity of the working fluid can be increased compared to aspects using an oil-based fluid. As a result, the heat transfer efficiency by sensible heat can be improved. Furthermore, the latent heat of vaporization of the working fluid can be increased compared to aspects using an oil-based fluid. As a result, the heat transfer efficiency by latent heat can also be improved. [Explanation of symbols]

[0107] 10...circulation flow path, 11...first heat exchange section, 12...second heat exchange section, 13...drive section, 14...spacer, 15...heat transfer member, 15a...heat collection fin, 15b...spacer, 16...heat transfer member, 16a...heat pipe, 17...heat transfer member, 17a...heat pipe, 18...heat transfer member, 18a...heat collection fin, 20...magnet, 21, 22...permanent magnet, 30...insulating material, yoke...40, 100...heat transfer system, 100A...heat transfer system, 100B...heat transfer system, 100C...heat transfer system, 100D...heat transfer system, 100E...heat transfer system, FL...working fluid, GS...surface, GU...underground, H...vertical hole, MF...magnetic field, PA...driving force, PB...driving force.

Claims

1. a circulation flow path having a first heat exchanger disposed along the ground surface and a second heat exchanger buried in the ground at a position deeper than the first heat exchanger, and in which a working fluid made of a temperature-sensitive magnetic fluid is sealed; a magnet buried in the ground at a depth between the first heat exchange unit and the second heat exchange unit, and applying a magnetic field to the working fluid to generate a driving force for circulating the working fluid in the circulation flow path. Heat transfer system.

2. the circulation flow path has a drive unit for generating the propulsive force, The drive portion extends along the depth direction, The magnets are arranged along the periphery of the drive unit. The heat transfer system of claim 1 .

3. The second heat exchange unit is disposed at a depth of 5 m or more underground. The heat transfer system of claim 2 .

4. The magnet is placed at a depth of 3 m to 6 m underground. The heat transfer system of claim 3 .

5. Further provided is a heat transfer member that transfers heat to the drive portion from a position deeper than the drive portion. The heat transfer system of claim 4 .

6. The heat transfer member includes a heat pipe. The heat transfer system of claim 5 .

7. The heat transfer member has a heat collecting fin. The heat transfer system of claim 5 .

8. The magnet is placed at a depth of 0.25 m to 3 m underground. The heat transfer system of claim 3 .

9. Further provided is a heat transfer member that transfers heat to the drive portion from a position deeper than the drive portion. The heat transfer system of claim 8 .

10. The heat transfer member includes a heat pipe. The heat transfer system of claim 9.

11. Further provided is a heat transfer member that transfers heat to the drive portion from a position shallower than the drive portion. The heat transfer system of claim 8 .

12. The heat transfer member has a heat collecting fin. The heat transfer system of claim 11.

13. The periphery of the second heat exchanger is covered with thermally conductive clay or silica sand. The heat transfer system of claim 1 .

14. The magnet is a permanent magnet. The heat transfer system of claim 2 .

15. further comprising a yoke for directing the magnetic field from the magnet to the drive unit; The heat transfer system of claim 14.

16. The working fluid is a water-based or alcohol-based fluid. The heat transfer system of claim 1 .

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