Heat pump and method for operating same

Abstract

A heat pump 10 has: a heat-absorbing part 11; a heat-radiating part 12; and a heat transport device 20 that receives a working fluid from which heat has been absorbed by the heat-absorbing part 11 and feeds the working fluid to the heat-radiating part 12, and receives the working fluid to which heat has been emitted from the heat-radiating part 12 and feeds the working fluid to the heat-absorbing part. The heat transport device 20 has: two spaces 21, 22 that are adjacent to each other, the two spaces 21, 22 including a first space 21, to which a magnetic field is applied and through which the working fluid from which heat has been absorbed is circulated, and a second space 22, to which either no magnetic field is applied or a magnetic field weaker than the magnetic field applied to the first space 21 is applied and through which the working fluid to which heat has been emitted is circulated; and a movable member 26 of which at least a portion is composed of a magnetic body, the movable member 26 being configured such that the portion composed of a magnetic body moves from one space among the two spaces 21, 22 to the other space and then moves into the one space.

Description

Heat pump and its operating method

[0001] The present invention relates to a heat pump utilizing the magnetocaloric effect and a method for operating the same.

[0002] A heat pump utilizing the magnetocaloric effect (hereinafter referred to as a "magnetic heat pump") generates a magnetocaloric effect by varying a magnetic field applied to a magnetic material, and heats or cools a working fluid by heat exchange with the magnetic material. A typical method for varying the magnetic field is to move (rotate) a magnetic field generator such as a permanent magnet relative to a flow path filled with a magnetic material or a flow path formed by a magnetic material (see, for example, Patent Documents 1 to 3).

[0003] JP 2019-509461 A JP 2019-143938 A JP 2020-041742 A

[0004] However, the above-mentioned methods have the following drawbacks. For example, increasing the strength of the magnetic field applied to the magnetic material is one way to generate a significant magnetocaloric effect. However, achieving this with a permanent magnet requires a heavy permanent magnet. Rotating such a heavy permanent magnet requires a support mechanism with sufficient mechanical strength and a powerful driving source, which inevitably increases costs. Furthermore, the flow direction of the working fluid relative to the magnetic material must be switched in synchronization with the rotation of the permanent magnet, necessitating a valve mechanism and control device for this purpose. This increases the complexity of the device and the risk of malfunction. On the other hand, rotating a flow path filled with a magnetic material or a flow path formed by a magnetic material requires special components such as rotary valves at the connection between the rotating and fixed parts. This also increases costs and can lead to malfunctions such as leakage.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to realize a simple configuration for varying the magnetic field relative to a magnetic body in a heat pump utilizing the magnetocaloric effect.

[0006] In order to achieve the above-mentioned object, the heat pump of the present invention is a heat pump that transfers heat using a working fluid, and includes a heat absorption section that causes the working fluid to absorb heat, a heat dissipation section that causes the working fluid that has absorbed heat to release heat, and a heat transport device that receives the working fluid that has absorbed heat from the heat absorption section and sends it out to the heat dissipation section, and receives the working fluid that has released heat from the heat dissipation section and sends it out to the heat absorption section. The heat transport device includes two adjacent spaces, including a first space to which a magnetic field is applied and through which the working fluid that has absorbed heat flows, and a second space to which no magnetic field is applied or a magnetic field weaker than the magnetic field applied to the first space is applied and through which the working fluid that has released heat flows, and a movable member at least a portion of which is made of a magnetic material and is configured so that the portion made of the magnetic material moves from one of the two spaces to the other space and then moves back to one of the spaces.

[0007] Furthermore, a method of operating a heat pump of the present invention is a method of operating a heat pump that transfers heat using a working fluid, and includes the steps of: causing the working fluid to absorb heat in a heat absorption section; causing the working fluid that has absorbed heat to release heat in a heat release section; and, in a heat transport device having two adjacent spaces, receiving the working fluid that has absorbed heat from the heat absorption section and sending it out to the heat release section, and receiving the working fluid that has released heat from the heat release section and sending it out to the heat absorption section. The step of receiving and sending out the working fluid includes the steps of circulating the working fluid that has absorbed heat through a first space of the two spaces to which a magnetic field is applied, and circulating the working fluid that has released heat through a second space to which no magnetic field is applied or to which a magnetic field weaker than that applied to the first space is applied; and moving a movable member, at least a portion of which is made of a magnetic material, within the two spaces, by moving the portion of the movable member made of a magnetic material from one of the two spaces to the other space and then moving it back to one of the spaces.

[0008] With this heat pump, the relative position of the magnetic body with respect to the magnetic field can be changed by simply moving the movable member, at least a portion of which is made of a magnetic material, thereby varying the magnetic field applied to the magnetic body. In other words, there is no need to move the magnetic field generating unit or the flow channel chamber in order to vary the magnetic field applied to the magnetic body, and therefore no complex structure or control is required.

[0009] According to the present invention, in a heat pump utilizing the magnetocaloric effect, the variation of the magnetic field relative to the magnetic body can be realized with a simple configuration.

[0010] Fig. 1 is a schematic configuration diagram of a magnetic heat pump according to a first embodiment of the present invention; Fig. 2 is a perspective view and a plan view showing an example of the configuration of a rotating plate of this embodiment; Fig. 3 is a schematic configuration diagram of a magnetic heat pump according to a second embodiment of the present invention; Fig. 4 is a schematic configuration diagram of a magnetic heat pump according to a third embodiment of the present invention; Fig. 5 is a schematic configuration diagram of a magnetic heat pump according to a fourth embodiment of the present invention;

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components common to each embodiment will be denoted by the same reference numerals in the drawings, and duplicated descriptions will be omitted as appropriate. In addition, different subscripts may be added after the same reference numerals to distinguish multiple components from one another.

[0012] (First embodiment) The configuration of a magnetic heat pump according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the magnetic heat pump of this embodiment. In the following description, terms indicating directions such as "up," "down," "right," and "left" are used based on Fig. 1, but these terms are for convenience and do not limit the position of the magnetic heat pump when in use.

[0013] The magnetic heat pump 10 utilizes the magnetocaloric effect to transfer heat from a heat-donating fluid flowing through a low-temperature flow path L1 to a heat-receiving fluid flowing through a high-temperature flow path L2, and includes a heat absorption section 11, a heat radiation section 12, and a heat transport device 20 that circulates a working fluid between them to transfer heat. The working fluid can be, for example, lubricating oil, water, or any other commonly used working fluid for magnetic heat pumps.

[0014] The heat absorption unit 11 is connected to the heat transport device 20 via pipes P1 and P2 and has a function of absorbing heat into the working fluid by heat exchange between the working fluid flowing through the pipes P1 and P2 and the heat-donating fluid flowing through the low-temperature side flow path L1. The heat dissipation unit 12 is connected to the heat transport device 20 via pipes P3 and P4 and has a function of dissipating heat into the working fluid by heat exchange between the working fluid flowing through the pipes P3 and P4 and the heat-receiving fluid flowing through the high-temperature side flow path L2.

[0015] The heat transport device 20 has two adjacent flow path chambers (spaces) 21 and 22. The two flow path chambers 21 and 22 are formed, for example, by dividing a cylindrical space into two left and right sections by a central partition wall 23. The two flow path chambers 21 and 22 include a first flow path chamber (first space) 21 having a semicircular flow path cross section and a second flow path chamber (second space) 22 also having a semicircular flow path cross section. The heat transport device 20 is fluidly connected to the heat absorption unit 11 and the heat radiation unit 12 so that a working fluid circulates through the heat transport device 20 between the heat absorption unit 11 and the heat radiation unit 12. That is, the heat transport device 20 is fluidly connected to the heat absorption unit 11 and the heat radiation unit 12 so that the working fluid that has absorbed heat in the heat absorption unit 11 is received and sent to the heat radiation unit 12, and the working fluid that has released heat in the heat radiation unit 12 is received and sent to the heat absorption unit 11. Specifically, the first flow path chamber 21 is connected to the heat absorption portion 11 via a pipe P1 and to the heat dissipation portion 12 via a pipe P3 to circulate the working fluid that has absorbed heat in the heat absorption portion 11. The second flow path chamber 22 is connected to the heat dissipation portion 12 via a pipe P4 and to the heat absorption portion 11 via a pipe P2 to circulate the working fluid that has released heat in the heat dissipation portion 12. This allows the working fluid to circulate through a circulation flow path consisting of the heat absorption portion 11, the pipe P1, the first flow path chamber 21, the pipe P3, the heat dissipation portion 12, the pipe P4, the second flow path chamber 22, and the pipe P2. A pump (not shown) is provided in any of the pipes P1 to P4 to circulate the working fluid along the circulation flow path.

[0016] The heat transport device 20 is configured such that a magnetic field is applied to the first flow channel chamber 21, but substantially no magnetic field is applied to the second flow channel chamber 22. Specifically, the heat transport device 20 includes a pair of permanent magnets 24, 25 arranged above and below the first flow channel chamber 21 as a magnetic field generator for applying a magnetic field to the first flow channel chamber 21. A magnetic field weaker than that applied to the first flow channel chamber 21 may be applied to the second flow channel chamber 22; however, it is preferable that no magnetic field be intentionally applied to the second flow channel chamber 22, except for unavoidable magnetic fields such as leakage magnetic fields. Instead of the permanent magnets 24, 25, electromagnets may be used as the magnetic field generator. However, considering that no power source is required, it is preferable to use the permanent magnets 24, 25. In this embodiment, the permanent magnets 24, 25 are provided at fixed positions relative to the two flow channel chambers 21, 22 and therefore do not move relative to the two flow channel chambers 21, 22.

[0017] Furthermore, the heat transport device 20 includes a circular rotating plate 26 made of a magnetic material and disposed within the two flow chambers 21 and 22. The rotating plate 26 is disposed through the partition wall 23 so as to intersect with the flow direction of the working fluid and is configured to rotate across the first flow chamber 21 and the second flow chamber 22. Therefore, as the rotating plate 26 rotates, it alternates between a state in which a magnetic field is applied to the first flow chamber 21 and a state in which a magnetic field is substantially not applied to the second flow chamber 22. A magnetocaloric effect occurs in the rotating plate 26, causing the temperature to rise when the fluid enters the first flow chamber 21 from the second flow chamber 22 and the temperature to drop when the fluid enters the second flow chamber 22 from the first flow chamber 21. Thus, the temperature of the rotating plate 26 reaches a steady state, maintaining a relatively high temperature in the first flow chamber 21 and a relatively low temperature in the second flow chamber 22.

[0018] Here, the operation of the magnetic heat pump 10 of this embodiment will be briefly described.

[0019] First, the working fluid absorbs heat from the heat-donating fluid flowing through the low-temperature side flow path L1 in the heat absorption section 11, and then flows through the pipe P1 and is supplied to the first flow path chamber 21 of the heat transport device 20. There, the working fluid is heated by contact (heat exchange) with the rotating plate 26, which is maintained at a relatively high temperature. The heated working fluid flows through the pipe P3 and is supplied to the heat dissipation section 12, where it releases heat to the heat-receiving fluid flowing through the high-temperature side flow path L2. The working fluid then flows through the pipe P4 and is supplied to the second flow path chamber 22 of the heat transport device 20, where it is cooled by contact (heat exchange) with the rotating plate 26, which is maintained at a relatively low temperature. The cooled working fluid flows through the pipe P2 and is supplied to the heat absorption section 11 again. By repeating this operation, the magnetic heat pump 10 transfers heat from the heat-donating fluid flowing through the low-temperature side flow path L1 to the heat-receiving fluid flowing through the high-temperature side flow path L2.

[0020] As described above, according to this embodiment, the magnetic field applied to the magnetic body can be varied by simply rotating the rotating plate 26 made of a magnetic material to change the relative position of the magnetic body with respect to the magnetic field. In other words, the magnetic field applied to the magnetic body can be varied without moving the permanent magnets 24, 25 or the flow channel chambers 21, 22, so no complex structure or control is required. In this way, the variation of the magnetic field applied to the magnetic body can be achieved with a simple configuration.

[0021] The shape of the rotating plate 26 is not particularly limited. For example, it may have a large number of through holes formed therein, or as shown in FIG. 2 , it may have a plurality of arc-shaped slits 27 formed concentrically. This increases the contact area (heat transfer area) between the working fluid and the rotating plate 26, thereby improving the heat exchange efficiency between them. Furthermore, gaps through which the working fluid flows are formed between the outer peripheral surface of the rotating plate 26 and the inner surfaces of the flow passage chambers 21 and 22 facing it. If sufficient heat exchange with the rotating plate 26 is achieved simply by the flow of the working fluid through these gaps, the rotating plate 26 may be a solid disk. Furthermore, the outer shape of the rotating plate 26 is not limited to a circle, and may be, for example, a regular polygon.

[0022] Furthermore, the entire rotating plate 26 does not have to be made of a magnetic material as long as it rotates to maintain a relatively high temperature in the first flow path chamber 21 and a relatively low temperature in the second flow path chamber 22. In other words, as long as at least the portion of the rotating plate 26 that moves alternately between the two flow path chambers 21 and 22 is made of a magnetic material, the other portions do not have to be made of a magnetic material.

[0023] In this embodiment, even when the rotary plate 26 is provided with a through-hole, a slit 27, or other penetration, the flow of the working fluid that prevails in each of the flow passage chambers 21, 22 is a flow that bypasses the periphery of the rotary plate 26 along the gap between the rotary plate 26 and the inner surface of each of the flow passage chambers 21, 22. This makes it possible to avoid disadvantages that may arise from providing a penetration in the rotary plate 26, as will be described below.

[0024] For example, in order to increase the amount of heat transfer that can be achieved by the magnetic heat pump 10, it is preferable to increase the rotation speed of the rotating plate 26 from the viewpoint of the magnetocaloric effect. However, if the rotation speed is increased, the working fluid that has flowed into the first flow passage chamber 21 (second flow passage chamber 22) does not pass through the through-holes of the rotating plate 26 and flow directly downstream, but instead flows partly into the second flow passage chamber 22 (first flow passage chamber 21). This causes two types of working fluid in different states (the working fluid that has absorbed heat in the heat absorption section 11 and the working fluid that has released heat in the heat release section 12) to mix, which may actually lead to a decrease in the performance of the magnetic heat pump 10. To prevent this, it is possible to reduce the rotation speed of the rotating plate 26 while increasing the amount (mass) of magnetic material that constitutes the rotating plate 26. However, increasing the amount of expensive magnetic material is generally undesirable from a cost perspective.

[0025] However, in this embodiment, as described above, the dominant flow of the working fluid in each flow path chamber 21, 22 is a flow that bypasses the rotating plate 26 along the gap formed around the rotating plate 26. Therefore, even if different types of working fluids mix between the flow path chambers 21, 22 through the through-holes in the rotating plate 26, the impact is extremely limited, and there is no need to reduce the rotation speed of the rotating plate 26 for this reason. In other words, in order to maintain the performance of the magnetic heat pump 10, there is no need to reduce the rotation speed of the rotating plate 26, and there is no need to increase the amount of magnetic material constituting the rotating plate 26. Therefore, even if the rotating plate 26 has through-holes, its rotation speed can be increased, and the amount of heat transfer that can be achieved by the magnetic heat pump 10 can be increased without increasing the amount of magnetic material constituting the rotating plate 26.

[0026] Second Embodiment Fig. 3 is a schematic diagram of a magnetic heat pump according to a second embodiment of the present invention. This embodiment differs from the first embodiment in that a plurality of heat transport devices are arranged between a heat absorption section and a heat radiation section. The following description will focus on this difference. For simplicity, permanent magnets in each heat transport device are omitted from Fig. 3.

[0027] In this embodiment, as described above, a plurality of heat transport devices 20 are arranged between the heat absorption unit 11 and the heat radiation unit 12. The plurality of heat transport devices 20 are fluidly connected to each other and to the heat absorption unit 11 and the heat radiation unit 12 so as to receive the working fluid that has absorbed heat in the heat absorption unit 11, sequentially transfer it between adjacent devices 20, and then send it to the heat radiation unit 12, and to receive the working fluid that has released heat in the heat radiation unit 12, sequentially transfer it between adjacent devices 20, and then send it to the heat absorption unit 11. Specifically, the plurality of first flow path chambers 21 are connected to each other in series via pipes P11 to P13, and the plurality of second flow path chambers 22 are connected to each other in series via pipes P14 to P16. As a result, the working fluid that absorbs heat in the heat absorption section 11 flows in series through multiple first flow path chambers 21 and is supplied to the heat dissipation section 12, and the working fluid that releases heat in the heat dissipation section 12 flows in series through multiple second flow path chambers 22 and is supplied to the heat absorption section 11.

[0028] Heat transfer by the magnetic heat pump 10 of this embodiment is performed as follows. That is, the working fluid that absorbs heat in the heat absorption section 11 flows sequentially through the multiple first flow path chambers 21, is heated by contact (heat exchange) with each of the rotating plates 26, and is then supplied to the heat dissipation section 12. Then, the working fluid that releases heat in the heat dissipation section 12 flows sequentially through the multiple second flow path chambers 22, is cooled by contact (heat exchange) with each of the rotating plates 26, and is then supplied again to the heat absorption section 11. By repeating this operation, the magnetic heat pump 10 transfers heat from the heat-donating fluid flowing through the low-temperature side flow path L1 to the heat-receiving fluid flowing through the high-temperature side flow path L2.

[0029] As described above, in this embodiment, by interposing multiple heat transport devices 20 between the heat absorption unit 11 and the heat radiation unit 12, the temperature change of the working fluid flowing between the heat absorption unit 11 and the heat radiation unit 12 can be increased compared to the first embodiment. Therefore, this embodiment is advantageous in that it can accommodate a larger temperature difference between the heat-donating fluid flowing through the low-temperature side flow path L1 and the heat-receiving fluid flowing through the high-temperature side flow path L2. The number of heat transport devices 20 is not limited to four as shown in the figure and can be appropriately set depending on the temperature difference between the heat-donating fluid flowing through the low-temperature side flow path L1 and the heat-receiving fluid flowing through the high-temperature side flow path L2. Furthermore, in this embodiment, the heat pump efficiency can be improved by appropriately selecting the magnetic material constituting the rotating plate 26 according to the operating temperature range of each heat transport device 20, which is estimated based on the temperature difference and the number of heat transport devices 20. That is, the heat pump efficiency can be improved by selecting a magnetic material that exhibits a large magnetocaloric effect for each heat transport device 20 within the expected operating temperature range.

[0030] (Third Embodiment) Fig. 4 is a schematic diagram of a magnetic heat pump according to a third embodiment of the present invention. This embodiment is a modification of the second embodiment, and differs from the second embodiment in that multiple working fluid circulation paths are formed, and separate working fluids circulate through each of the paths. That is, this embodiment differs from the second embodiment in that heat is transferred between a heat absorption section and a heat radiation section by multiple working fluids. The following description will focus on these differences. Note that, for simplicity, permanent magnets in each heat transport device are omitted from Fig. 4.

[0031] In this embodiment, the first heat transport device 20a (the heat transport device closest to the heat absorption portion) is fluidly connected to the heat absorption portion 11 so that the second flow path chamber 22a circulates the working fluid that has absorbed heat in the heat absorption portion 11. Specifically, a pipe P1 is connected to the inlet of the second flow path chamber 22a of the first heat transport device 20a, and a pipe P2 is connected to the outlet. Thus, the pipes P1 and P2 form an independent circulation path (hereinafter referred to as the "first circulation path"), allowing the working fluid to circulate between the heat absorption portion 11 and the second flow path chamber 22a of the first heat transport device 20a. A pump (not shown) is provided in either the pipe P1 or P2 to circulate the working fluid along the first circulation path P1 or P2.

[0032] Furthermore, the first heat transport device 20a and the second heat transport device 20b are fluidly connected to each other such that the first flow path chamber 21a of the first heat transport device 20a circulates the working fluid flowing out from the second flow path chamber 22b of the second heat transport device 20b (the heat transport device adjacent to the first heat transport device on the heat dissipation side), and the second flow path chamber 22b of the second heat transport device 20b circulates the working fluid flowing out from the first flow path chamber 21a of the first heat transport device 20a (the heat transport device adjacent to the second heat transport device on the heat absorption side). Specifically, the outlet of the first flow passage chamber 21a of the first heat transport device 20a is connected to the inlet of the second flow passage chamber 22b of the second heat transport device 20b by a pipe P21, and the outlet of the second flow passage chamber 22b of the second heat transport device 20b is connected to the inlet of the first flow passage chamber 21a of the first heat transport device 20a by a pipe P22. This allows the pipes P21 and P22 to form an independent circulation passage (hereinafter referred to as the "second circulation passage"), allowing the working fluid to circulate between the first flow passage chamber 21a of the first heat transport device 20a and the second flow passage chamber 22b of the second heat transport device 20b. A pump (not shown) is provided in either the pipe P21 or P22 to circulate the working fluid along the second circulation passage P21 or P22.

[0033] Furthermore, the second heat transport device 20b and the third heat transport device 20c are fluidly connected to each other such that the first flow path chamber 21b of the second heat transport device 20b circulates the working fluid flowing out from the second flow path chamber 22c of the third heat transport device (the heat transport device adjacent to the second heat transport device on the heat dissipation side) 20c, and the second flow path chamber 22c of the third heat transport device 20c circulates the working fluid flowing out from the first flow path chamber 21b of the second heat transport device (the heat transport device adjacent to the third heat transport device on the heat absorption side) 20b. Specifically, the outlet of the first flow passage chamber 21b of the second heat transport device 20b is connected to the inlet of the second flow passage chamber 22c of the third heat transport device 20c by a pipe P23, and the outlet of the second flow passage chamber 22 of the third heat transport device 20c is connected to the inlet of the first flow passage chamber 21b of the second heat transport device 20b by a pipe P24. This allows the pipes P23 and P24 to form an independent circulation passage (hereinafter referred to as the "third circulation passage"), allowing the working fluid to circulate between the first flow passage chamber 21b of the second heat transport device 20b and the second flow passage chamber 22c of the third heat transport device 20c. A pump (not shown) is provided in either the pipe P23 or P24 to circulate the working fluid along the third circulation passage P23 or P24.

[0034] Furthermore, the third heat transport device 20c and the fourth heat transport device 20d are fluidly connected to each other such that the first flow path chamber 21c of the third heat transport device 20c circulates the working fluid flowing out from the second flow path chamber 22d of the fourth heat transport device (the heat transport device adjacent to the third heat transport device on the heat dissipation side) 20d, and the second flow path chamber 22d of the fourth heat transport device 20d circulates the working fluid flowing out from the first flow path chamber 21c of the third heat transport device (the heat transport device adjacent to the fourth heat transport device on the heat absorption side) 20c. Specifically, the outlet of the first flow passage chamber 21c of the third heat transport device 20c is connected to the inlet of the second flow passage chamber 22d of the fourth heat transport device 20d by a pipe P25, and the outlet of the second flow passage chamber 22d of the fourth heat transport device 20d is connected to the inlet of the first flow passage chamber 21c of the third heat transport device 20c by a pipe P26. This allows the pipes P25 and P26 to form an independent circulation passage (hereinafter referred to as the "fourth circulation passage"), allowing the working fluid to circulate between the first flow passage chamber 21c of the third heat transport device 20c and the second flow passage chamber 22d of the fourth heat transport device 20d. A pump (not shown) is provided in either the pipe P25 or P26 to circulate the working fluid along the fourth circulation passage P25 or P26.

[0035] Furthermore, the fourth heat transport device 20d (the heat transport device closest to the heat dissipation unit) is fluidly connected to the heat dissipation unit 12 so that the first flow path chamber 21d circulates the working fluid that has released heat in the heat dissipation unit 12. Specifically, a pipe P3 is connected to the outlet of the first flow path chamber 21d of the fourth heat transport device 20d, and a pipe P4 is connected to the inlet. This allows the pipes P3 and P4 to form an independent circulation path (hereinafter referred to as the "fifth circulation path"), allowing the working fluid to circulate between the heat dissipation unit 12 and the first flow path chamber 21d of the fourth heat transport device 20d. A pump (not shown) is provided in either the pipe P3 or P4 to circulate the working fluid along the fifth circulation path P3 or P4.

[0036] Heat transfer by the magnetic heat pump 10 of this embodiment occurs as follows. After absorbing heat in the heat absorption section 11, the working fluid circulating through the first circulation paths P1 and P2 is cooled by contact (heat exchange) with the rotating plate 26a in the second flow path chamber 22a of the first heat transport device 20a. The heat thus removed is transferred through the rotating plate 26a to the first flow path chamber 21a of the first heat transport device 20a and given to the working fluid circulating through the second circulation paths P21 and P22. The working fluid thus heated is supplied to the second flow path chamber 22b of the second heat transport device 20b, where it is cooled by contact (heat exchange) with the rotating plate 26b. The heat thus removed is transferred through the rotating plate 26b to the first flow path chamber 21b of the second heat transport device 20b and given to the working fluid circulating through the third circulation paths P23 and P24. The heated working fluid is supplied to the second flow passage chamber 22c of the third heat transport device 20c, where it is cooled by heat removal through contact with the rotating plate 26c (heat exchange). The removed heat is transferred through the rotating plate 26c to the first flow passage chamber 21c of the third heat transport device 20c and given to the working fluid circulating through the fourth circulation passages P25 and P26. The heated working fluid is supplied to the second flow passage chamber 22d of the fourth heat transport device 20d, where it is cooled by heat removal through contact with the rotating plate 26d (heat exchange). The removed heat is transferred through the rotating plate 26d to the first flow passage chamber 21d of the fourth heat transport device 20d and given to the working fluid circulating through the fifth circulation passages P3 and P4. The heated working fluid is supplied to the heat dissipation section 12, where it releases heat. By repeating this operation, the magnetic heat pump 10 transfers heat from the heat-donating fluid flowing through the low-temperature side flow path L1 to the heat-receiving fluid flowing through the high-temperature side flow path L2.

[0037] As described above, unlike the second embodiment, this embodiment does not require the working fluid to circulate along a single circulation path, and the length of each circulation path is short. Therefore, this embodiment is advantageous over the second embodiment in that the pressure difference between the flow path chambers 21 and 22 in each heat transport device 20 is smaller, reducing the likelihood of leakage of the working fluid. Like the second embodiment, this embodiment can also accommodate a larger temperature difference between the heat-donating fluid flowing through the low-temperature side flow path L1 and the heat-receiving fluid flowing through the high-temperature side flow path L2. Also, like the second embodiment, the heat pump efficiency can be improved by appropriately selecting the magnetic material depending on the expected operating temperature range.

[0038] (Fourth embodiment) Fig. 5 is a schematic diagram of a magnetic heat pump according to a fourth embodiment of the present invention. This embodiment is a modification of the third embodiment, and differs from the third embodiment in that the circulation flow path for the working fluid is omitted, and instead, two flow path chambers that were previously connected via a circulation flow path are directly connected. The following description will focus on these differences. Note that, for simplicity, permanent magnets in each heat transport device are not shown in Fig. 5.

[0039] In the third embodiment, the purpose of circulating the working fluid is to mix the working fluid in the first flow passage 21a of the first heat transport device 20a and the working fluid in the second flow passage 22b of the second heat transport device 20b in the second circulation passages P21 and P22, and to make the temperatures of the two fluids approximately uniform (although there may be some temperature variation depending on the position). Specifically, in the first flow passage 21a of the first heat transport device 20a, the temperature of the working fluid is maintained lower than the temperature of the rotating plate 26a, and in the second flow passage 22b of the second heat transport device 20b, the temperature of the working fluid is maintained higher than the temperature of the rotating plate 26b. This is because, if this is not done, the temperature of the working fluid in the first flow passage chamber 21a of the first heat transport device 20a will rise to the temperature of the rotating plate 26a, preventing heat transfer between the two, and the temperature of the working fluid in the second flow passage chamber 22b of the second heat transport device 20b will fall to the temperature of the rotating plate 26b, preventing heat transfer between the two.

[0040] In contrast, this embodiment achieves the same effect as the third embodiment with a different configuration. That is, in this embodiment, in order to mix the working fluids in the two flow channel chambers, the two flow channel chambers are connected to form a single space, as shown in Fig. 5, and the working fluid contained therein is agitated.

[0041] Specifically, the first heat transport device 20a and the second heat transport device 20b are connected to each other so that the first flow passage chamber 21a of the first heat transport device 20a and the second flow passage chamber 22b of the second heat transport device 20b form a single space. The spaces 21a and 22b contain a working fluid, and stirring blades 31 are provided to stir the working fluid. This allows the temperature of the working fluid in the spaces 21a and 22b to be substantially uniform, achieving heat transfer from the rotating plate 26a to the working fluid and from the working fluid to the rotating plate 26b. The second heat transport device 20b and the third heat transport device 20c are connected to each other so that the first flow passage chamber 21b of the second heat transport device 20b and the second flow passage chamber 22c of the third heat transport device 20c form a single space. The spaces 21b and 22c contain a working fluid, and are provided with stirring blades 32 that stir the working fluid. This allows the temperature of the working fluid in the spaces 21b and 22c to be substantially uniform, and heat can be transferred from the rotating plate 26b to the working fluid and from the working fluid to the rotating plate 26c. The third heat transport device 20c and the fourth heat transport device 20d are connected to each other so that the first flow path chamber 21c of the third heat transport device 20c and the second flow path chamber 22d of the fourth heat transport device 20d form a single space. The spaces 21c and 22d contain a working fluid, and are provided with stirring blades 33 that stir the working fluid. This allows the temperature of the working fluid in the spaces 21c and 22d to be substantially uniform, and heat can be transferred from the rotating plate 26c to the working fluid and from the working fluid to the rotating plate 26d.

[0042] In the above-described embodiments, the rotating plate 26 is exemplified as a movable member that generates the magnetocaloric effect, but other types of movable members may be used as long as they are configured to move from one of the two flow channel chambers to the other and then back to one of the flow channel chambers. For example, such movable members may be ones that move back and forth between the two flow channel chambers.

[0043] REFERENCE SIGNS LIST 10 Magnetic heat pump 11 Heat absorption section 12 Heat radiation section 20, 20a to 20d Heat transport device 21, 21a to 21d First flow path chamber 22, 22a to 22d Second flow path chamber 23 Partition wall 24, 25 Permanent magnet 26 Rotating plate 27 Slit 31 to 33 Stirring blades P1 to P4, P11 to P16, P21 to P26 Piping

Claims

1. A heat pump that transfers heat using a working fluid, comprising: a heat absorption section that causes the working fluid to absorb heat; a heat dissipation section that causes the working fluid that has absorbed the heat to release heat; and a heat transport device that receives the working fluid that has absorbed the heat from the heat absorption section and sends it out to the heat dissipation section, and receives the working fluid that has released the heat from the heat dissipation section and sends it out to the heat absorption section, wherein the heat transport device has: two adjacent spaces including a first space to which a magnetic field is applied and through which the working fluid that has absorbed the heat flows, and a second space to which no magnetic field is applied or a magnetic field weaker than the magnetic field applied to the first space is applied and through which the working fluid that has released the heat flows; and a movable member at least a portion of which is made of a magnetic material and which is configured so that the portion made of the magnetic material moves from one of the two spaces to the other space and then moves back to one of the spaces.

2. The heat pump as described in claim 1, further comprising at least one other heat transport device having the same configuration as the heat transport device, which receives the working fluid that has absorbed the heat from the heat transport device and sends it to the heat dissipation section, and receives the working fluid that has released the heat from the heat dissipation section and sends it to the heat transport device, wherein the heat transport device sends the working fluid that has absorbed the heat to the heat dissipation section via the at least one other heat transport device, and receives the working fluid that has released the heat from the heat dissipation section via the at least one other heat transport device.

3. A heat pump that transfers heat by a plurality of working fluids, comprising: a heat absorption section that causes one of the plurality of working fluids to absorb heat; a heat dissipation section that causes the other of the plurality of working fluids to release heat; and a plurality of heat transport devices that use the remaining working fluid of the plurality of working fluids to transfer heat from the working fluid that absorbed the heat to the working fluid that released the heat, wherein each of the heat transport devices: a first space to which a magnetic field is applied, and a second space to which a magnetic field is not applied or a magnetic field weaker than that applied to the first space is applied, the first space circulating a working fluid that has released heat in a heat transport device that is closest to a heat dissipation unit among the plurality of heat transport devices, and a working fluid that has flowed out of the second space of a heat transport device that is adjacent to the remaining heat transport device on the heat dissipation unit side among the remaining heat transport devices, and the second space circulating a working fluid that has absorbed heat in a heat transport device that is closest to a heat absorption unit among the plurality of heat transport devices, and a working fluid that has flowed out of the first space of a heat transport device that is adjacent to the remaining heat transport device on the heat absorption unit side among the remaining heat transport devices; and a movable member at least a portion of which is made of a magnetic material, the portion made of the magnetic material being configured to move from one of the two spaces to the other space and then to one of the spaces.

4. A heat pump that transfers heat by a plurality of working fluids, comprising: a heat absorption section that causes one of the plurality of working fluids to absorb heat; a heat dissipation section that causes the other of the plurality of working fluids to release heat; and a plurality of heat transport devices that use the remaining working fluid of the plurality of working fluids to transfer heat from the working fluid that absorbed the heat to the working fluid that released the heat, wherein each of the heat transport devices: a first space to which a magnetic field is applied, and a second space to which a magnetic field is not applied or a magnetic field weaker than that applied to the first space is applied, the first space being a space through which a working fluid that has released heat flows in a heat transport device that is closest to a heat dissipation unit among the plurality of heat transport devices, and the remaining heat transport devices being configured to form a single space together with the second space of a heat transport device adjacent to the remaining heat transport device on the heat dissipation unit side and to accommodate a working fluid therein, and the second space being a space through which a working fluid that has absorbed heat flows in a heat transport device that is closest to a heat absorption unit among the plurality of heat transport devices, and the remaining heat transport devices being configured to form a single space together with the first space of a heat transport device adjacent to the remaining heat transport device on the heat absorption unit side and to accommodate a working fluid therein; and a movable member at least a portion of which is made of a magnetic material, the portion made of the magnetic material being configured to move from one of the two spaces to the other space and then to move to one of the spaces.

5. The heat pump according to claim 4, further comprising an agitator blade disposed within said one space for agitating said working fluid contained in said one space.

6. The heat pump according to any one of claims 1 to 5, wherein the movable member is a rotating plate that rotates across the two spaces.

7. The heat pump according to claim 6, wherein a gap for circulating the working fluid is formed between the outer circumferential surface of the rotating plate and the inner surface of each of the spaces opposing the outer circumferential surface.

8. A heat pump according to any one of claims 1 to 5, wherein the heat transport device is provided at a fixed position relative to the two spaces and has a magnetic field generating unit that applies a magnetic field to the first space.

9. The heat pump according to claim 8, wherein the magnetic field generating section is made of a permanent magnet.

10. A method of operating a heat pump that transfers heat by a working fluid, comprising: a step of causing the working fluid to absorb heat in a heat absorption section; a step of causing the working fluid that has absorbed the heat to release the heat in a heat release section; and a step of receiving the working fluid that has absorbed the heat from the heat absorption section and sending it to the heat release section, and receiving the working fluid that has released the heat from the heat release section and sending it to the heat absorption section, in a heat transport device having two adjacent spaces, wherein the step of receiving and sending out the working fluid comprises the steps of: circulating the working fluid that has absorbed the heat through a first space of the two spaces to which a magnetic field is applied, and circulating the working fluid that has released the heat through a second space to which no magnetic field is applied or to which a magnetic field weaker than that applied to the first space is applied; A method for operating a heat pump, comprising: a step of moving a movable member, at least a portion of which is made of a magnetic material, within the two spaces, in which the portion of the movable member made of the magnetic material is moved from one of the two spaces to the other of the two spaces, and then moved back to one of the spaces.

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