U.S. patent application number 13/872781 was filed with the patent office on 2013-09-05 for magnetic refrigeration system.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. The applicant listed for this patent is KABUSHIKI KAISHA TOSHIBA. Invention is credited to Shiori Kaji, Tadahiko Kobayashi, Akiko Saito, Ryosuke YAGI.
Application Number | 20130227965 13/872781 |
Document ID | / |
Family ID | 45993314 |
Filed Date | 2013-09-05 |
United States Patent
Application |
20130227965 |
Kind Code |
A1 |
YAGI; Ryosuke ; et
al. |
September 5, 2013 |
MAGNETIC REFRIGERATION SYSTEM
Abstract
According to one embodiment, a magnetic refrigeration system
includes a first heat exchange section, a magnetic field changing
section, a first heat transport medium, a second heat transport
medium, and a transport section. The first heat exchange section
includes a magnetocaloric effect material. The magnetic field
changing section is configured to change magnetic field to the
first heat exchange section. The second heat transport medium is
separated from the first heat transport medium. The second heat
transport medium is different from the first heat transport medium
in specific heat per unit volume. The transport section is
configured to sequentially feed the first heat exchange section
with the first heat transport medium and the second heat transport
medium.
Inventors: |
YAGI; Ryosuke;
(Kanagawa-Ken, JP) ; Saito; Akiko; (Kanagawa-Ken,
JP) ; Kobayashi; Tadahiko; (Kanagawa-Ken, JP)
; Kaji; Shiori; (Kanagawa-Ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOSHIBA |
Minato-ku |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Toshiba
Minato-ku
JP
|
Family ID: |
45993314 |
Appl. No.: |
13/872781 |
Filed: |
April 29, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP10/69297 |
Oct 29, 2010 |
|
|
|
13872781 |
|
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Current U.S.
Class: |
62/3.1 |
Current CPC
Class: |
Y02B 30/00 20130101;
F25B 2321/002 20130101; Y02B 30/66 20130101; F25B 21/00
20130101 |
Class at
Publication: |
62/3.1 |
International
Class: |
F25B 21/00 20060101
F25B021/00 |
Claims
1. A magnetic refrigeration system comprising: a first heat
exchange section including a magnetocaloric effect material; a
magnetic field changing section configured to change magnetic field
to the first heat exchange section; a first heat transport medium;
a second heat transport medium separated from the first heat
transport medium and being different from the first heat transport
medium in specific heat per unit volume; and a transport section
configured to sequentially feed the first heat exchange section
with the first heat transport medium and the second heat transport
medium.
2. The system according to claim 1, wherein the transport section
feeds the first heat exchange section with the first heat transport
medium having a higher specific heat per unit volume than the
second heat transport medium, and the magnetic field changing
section applies the magnetic field to the first heat exchange
section to cause the heat exchange section to generate heat.
3. The system according to claim 1, wherein the transport section
feeds the first heat exchange section with the first heat transport
medium having a higher specific heat per unit volume than the
second heat transport medium, and the magnetic field changing
section removes the magnetic field applied to the first heat
exchange section to cause the heat exchange section to absorb
heat.
4. The system according to claim 1, wherein the first heat exchange
section includes a first region and a second region configured to
pass the heat transport media, when the first region is fed with
the first heat transport medium, the second region is fed with the
second heat transport medium, and when the first region is fed with
the second heat transport medium, the second region is fed with the
first heat transport medium.
5. The system according to claim 1, wherein one of the first heat
transport medium and the second heat transport medium is liquid,
and the other is gas.
6. The system according to claim 1, further comprising: a second
heat exchange section configured to perform heat exchange between
the first heat transport medium flowing out of the first heat
exchange section and a heat exchange target.
7. The system according to claim 6, further comprising: an ejecting
section configured to eject the second heat transport medium to
outside on inflow side of the second heat exchange section; and a
feeding section configured to feed the second heat transport medium
from outside on outflow side of the second heat exchange
section.
8. The system according to claim 7, wherein the first heat
transport medium is liquid, the second heat transport medium is
gas, and the ejecting section includes a gas-liquid separation
membrane.
9. The system according to claim 7, wherein the feeding section
feeds the second heat transport medium in a same amount as the
second heat transport medium ejected by the ejecting section.
10. The system according to claim 1, wherein the magnetocaloric
effect material includes at least one selected from the group
consisting of Gd (gadolinium), a Gd compound, an intermetallic
compound made of various rare earth elements and transition metal
elements, a Ni.sub.2MnGa alloy, a GdGeSi compound, a
LaFe.sub.13-based compound, and LaFe.sub.13H.
11. The system according to claim 1, wherein the magnetic field
changing section includes a magnetic field generating section and a
moving section configured to change relative position of the first
heat exchange section and the magnetic field generating
section.
12. The system according to claim 1, wherein the magnetic field
changing section includes an electromagnet and a switch configured
to switch between energization and deenergization of the
electromagnet.
13. The system according to claim 6, further comprising: a piping
connecting the first heat exchange section, the second heat
exchange section, and the transport section in a closed loop.
14. The system according to claim 1, wherein the first heat
transport medium and the second heat transport medium are separated
from each other.
15. The system according to claim 1, wherein the first heat
transport medium and the second heat transport medium are one of
gas, liquid, and solid.
16. The system according to claim 1, wherein the second heat
transport medium is air or nitrogen gas.
17. The system according to claim 1, wherein the first heat
transport medium is at least one selected from the group consisting
of water, an oil-based medium, and a solvent-based medium.
18. The system according to claim 13, wherein the transport section
circulates the first heat transport medium and the second heat
transport medium in a channel formed in a closed loop.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of International
Application PCT/JP2010/069297, filed on Oct. 29, 2010; the entire
contents of which are incorporated herein by reference.
FIELD
[0002] Embodiments described herein relate generally to a magnetic
refrigeration system.
BACKGROUND
[0003] Recently, as one of the environment-conscious and efficient
refrigeration technologies, the magnetic refrigeration technology
using the magnetocaloric effect has been raising expectations and
activating research and development. In the magnetic refrigeration
technology, a magnetic refrigeration cycle is configured using the
magnetocaloric effect to produce a high temperature section and a
low temperature section.
[0004] As one of such magnetic refrigeration technologies, the
refrigeration technology called the AMR (active magnetic
regenerative refrigeration) technique is proposed. Conventionally,
the lattice entropy has been placed as an impediment to magnetic
refrigeration in the cryogenic region. However, the AMR technique
rather actively utilizes the lattice entropy. In the AMR technique,
the magnetic refrigeration operation using the magnetocaloric
effect is performed by a component including a magnetocaloric
effect material. Simultaneously, the cold heat generated by this
magnetic refrigeration operation is stored in that component.
[0005] The AMR technique can achieve a higher heat exchange
efficiency than the gas refrigeration technology using the gas
compression-expansion cycle.
[0006] However, from the viewpoint of energy saving and the like,
further improvement in heat exchange efficiency is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic view for illustrating a magnetic
refrigeration system according to a first embodiment;
[0008] FIG. 2 is a schematic sectional view for illustrating the
heat exchange section;
[0009] FIG. 3 is a flow chart for illustrating the function of the
heat exchange section according to the first embodiment;
[0010] FIGS. 4A and 4B are schematic sectional views for
illustrating heat exchange in the heat exchange section according
to the first embodiment;
[0011] FIG. 5 is a schematic view for illustrating a magnetic
refrigeration system according to a second embodiment;
[0012] FIGS. 6A and 6B are schematic views for illustrating
magnetic refrigeration systems according to a third embodiment;
[0013] FIGS. 7A and 7B are schematic sectional views for
illustrating the heat exchange section 1 of the magnetic
refrigeration system according to the embodiment;
[0014] FIG. 8 is a schematic sectional view for illustrating a heat
exchange section 51 of the AMR magnetic refrigeration system
according to the comparative example; and
[0015] FIG. 9 is a graph showing the comparison between the heat
transport efficiency in Practical example 1 and the heat transport
efficiency in Comparative example 1.
DETAILED DESCRIPTION
[0016] In general, according to one embodiment, a magnetic
refrigeration system includes a first heat exchange section, a
magnetic field changing section, a first heat transport medium, a
second heat transport medium, and a transport section.
[0017] The first heat exchange section includes a magnetocaloric
effect material.
[0018] The magnetic field changing section is configured to change
magnetic field to the first heat exchange section.
[0019] The second heat transport medium is separated from the first
heat transport medium.
The second heat transport medium is different from the first heat
transport medium in specific heat per unit volume.
[0020] The transport section is configured to sequentially feed the
first heat exchange section with the first heat transport medium
and the second heat transport medium.
[0021] Embodiments will now be illustrated with reference to the
drawings. In the drawings, similar components are labeled with like
reference numerals, and the detailed description thereof is omitted
appropriately.
First Embodiment
[0022] FIG. 1 is a schematic view for illustrating a magnetic
refrigeration system according to a first embodiment.
[0023] As shown in FIG. 1, the magnetic refrigeration system 100
includes a heat exchange section (ARM bed) 1 (first heat exchange
section), a magnetic field generating section 2, a moving section
3, a high temperature side heat exchange section 4 (second heat
exchange section), a low temperature side heat exchange section 5
(second heat exchange section), a piping 6, a piping 7, a heat
transport medium 8, a heat transport medium 9, a transport section
10, a transport section 11, and a control section 24.
[0024] FIG. 2 is a schematic sectional view for illustrating the
heat exchange section.
[0025] In FIG. 2, the moving direction of the heat transport medium
8, 9 is taken as x direction, and a direction perpendicular thereto
is taken as y direction.
[0026] The heat exchange section 1 including a magnetocaloric
effect material includes a region 14, a region 12 (first region)
connected to the piping 6, and a region 13 (second region)
connected to the piping 7.
[0027] The region 14 is configured to include a magnetocaloric
effect material. The region 14 can be configured to include a
magnetocaloric effect material such as Gd (gadolinium).
[0028] The region 12 is provided so as to penetrate through the
region 14. Thus, the outer peripheral surface of the region 12 is
in contact with the region 14. The region 12 can be e.g. a channel
penetrating through the region 14.
[0029] The heat transport medium 8 fed through the piping 6 is
enabled to flow through the region 12.
[0030] The region 13 is provided so as to penetrate through the
region 14. Thus, the outer peripheral surface of the region 13 is
in contact with the region 14. The region 13 can be e.g. a channel
penetrating through the region 14.
[0031] The heat transport medium 9 fed through the piping 7 is
enabled to flow through the region 13.
[0032] Here, the heat transport medium 8 flowing through the region
12 and the heat transport medium 9 flowing through the region 13
are separated from each other by the region 14. This prevents the
heat transport medium 8 and the heat transport medium 9 from mixing
with each other.
[0033] As described later, heat generation and heat absorption
occur in the region 14. Heat exchange occurs between the region 14
and the heat transport medium 8 located in the region 12.
Furthermore, heat exchange occurs between the region 14 and the
heat transport medium 9 located in the region 13.
[0034] Here, for instance, in the case where the region 12 is fed
with a heat transport medium 80a, the region 13 is fed with a heat
transport medium 90b. In the case where the region 12 is fed with a
heat transport medium 80b, the region 13 is fed with a heat
transport medium 90a.
[0035] The aforementioned region 14 preferably has a configuration
(e.g., a plate-like body free from voids and the like) for passing
the heat transport medium 8, 9 and preventing the heat transport
media from mixing with each other. However, the embodiment is not
limited thereto.
[0036] For instance, a partition, not shown, for preventing passage
of the heat transport medium can be provided between the region 14
and the region 12 and between the region 14 and the region 13. For
instance, a tubular body can be provided as the partition, not
shown, so that the inside of the tubular body constitutes the
region 12, 13 and the outside of the tubular body constitutes the
region 14. Then, the region 14 can be formed from a sintered body
including voids, or formed by packing granular bodies.
[0037] The magnetocaloric effect material is not limited to Gd
(gadolinium) described above, but only need to be a material
developing the magnetocaloric effect. The magnetocaloric effect
material can be any of e.g. Gd compounds of Gd (gadolinium) mixed
with various elements, intermetallic compounds made of various rare
earth elements and transition metal elements, Ni.sub.2MnGa alloys,
GdGeSi compounds, LaFe.sub.13-based compounds, and various magnetic
materials such as LaFe.sub.13H.
[0038] The magnetic field generating section 2 is placed outside
the heat exchange section 1 and applies a magnetic field to the
heat exchange section 1.
[0039] The magnetic field generating section 2 can be e.g. a
permanent magnet. The permanent magnet can be e.g. a NdFeB
(neodymium-iron-boron) magnet, SmCo (samarium-cobalt) magnet, or
ferrite magnet.
[0040] The moving section 3 is connected to the magnetic field
generating section 2 and changes the relative position of the heat
exchange section 1 and the magnetic field generating section 2.
[0041] Here, changing the relative position means changing the
relative position of the heat exchange section 1 and the magnetic
field generating section 2 to enable switching between the position
22 (ON position) where the magnetic field generating section 2
applies the magnetic field to the heat exchange section 1 and the
position 23 (OFF position) where the magnetic field generating
section 2 does not apply the magnetic field to the heat exchange
section 1.
[0042] Thus, by causing the moving section 3 to change the relative
position of the heat exchange section 1 and the magnetic field
generating section 2, the magnetic field can be applied to the heat
exchange section 1, and the magnetic field applied to the heat
exchange section 1 can be removed. In the heat exchange section 1,
heat generation and heat absorption occur by application of the
magnetic field and removal of the magnetic field. The details on
the function of the heat exchange section 1 will be described
later.
[0043] The moving section 3 can be e.g. a section for applying
mechanical variation to the magnetic field generating section 2 to
change the relative position of the heat exchange section 1 and the
magnetic field generating section 2.
[0044] In the case illustrated in FIG. 1, the magnetic field
generating section 2 and the moving section 3 constitute a magnetic
field changing section for changing the magnetic field to the heat
exchange section 1.
[0045] In the case illustrated in FIG. 1, the moving section 3 is
connected to the magnetic field generating section 2 to apply
mechanical variation to the magnetic field generating section 2.
However, alternatively, the moving section 3 may be connected to
the heat exchange section 1 to apply mechanical variation to the
heat exchange section 1.
[0046] The moving section 3 can include e.g. driving means such as
a motor.
[0047] In the foregoing, as the magnetic field generating section
2, a permanent magnet is illustrated. However, for instance, an
electromagnet can also be used as the magnetic field generating
section 2. In the case of using an electromagnet as the magnetic
field generating section 2, the moving section 3 can be configured
to apply mechanical variation to the magnetic field generating
section 2. However, alternatively, the moving section 3 can also be
configured as e.g. a switch for switching between energization and
deenergization of the electromagnet.
[0048] The high temperature side heat exchange section 4 performs
heat exchange between the heat transport medium 8 heated in the
heat exchange section 1 and a heat exchange target, not shown. The
high temperature side heat exchange section 4 can be e.g. a section
for heating air by performing heat exchange between the heat
transport medium 8 at high temperature and air.
[0049] The low temperature side heat exchange section 5 performs
heat exchange between the heat transport medium 9 subjected to heat
absorption in the heat exchange section 1 and a heat exchange
target, not shown. The low temperature side heat exchange section 5
can be e.g. a section for cooling air by performing heat exchange
between the heat transport medium 9 at low temperature and air.
[0050] The piping 6 connects the heat exchange section 1, the high
temperature side heat exchange section 4, and the transport section
10 in a closed loop. Thus, the heat transport medium 8 can be
circulated in the closed loop channel formed from the heat exchange
section 1, the high temperature side heat exchange section 4, the
transport section 10, and the piping 6.
[0051] The piping 7 connects the heat exchange section 1, the low
temperature side heat exchange section 5, and the transport section
11 in a closed loop. Thus, the heat transport medium 9 can be
circulated in the closed loop channel formed from the heat exchange
section 1, the low temperature side heat exchange section 5, the
transport section 11, and the piping 7.
[0052] The heat transport medium 8 can be composed of two or more
heat transport media different in specific heat per unit volume.
The heat transport medium 8 is composed of e.g. a heat transport
medium 80a (first heat transport medium) and a heat transport
medium 80b (second heat transport medium) having a lower specific
heat per unit volume than the heat transport medium 80a.
[0053] The heat transport medium 9 can be composed of two or more
heat transport media different in specific heat per unit volume.
The heat transport medium 9 is composed of e.g. a heat transport
medium 90a (first heat transport medium) and a heat transport
medium 90b (second heat transport medium) having a lower specific
heat per unit volume than the heat transport medium 90a.
[0054] The heat transport medium 80a and the heat transport medium
80b are separated from each other. The heat transport medium 90a
and the heat transport medium 90b are separated from each
other.
[0055] Here, being separated means that heat transport media
different in specific heat per unit volume form respective phases
with respect to the moving direction of the heat transport
media.
[0056] In forming phases, it is preferable that each heat transport
medium be not mixed with a different heat transport medium.
However, the case where a particular heat transport medium is mixed
with a different heat transport medium in a volume ratio of 30% or
less may also be regarded as forming respective phases.
[0057] For instance, the heat transport media can be water and air,
which has a lower specific heat per unit volume than water. In this
case, air may partially dissolve in water. However, the solubility
of air in water is 0 vol % or more and 30 vol % or less. Thus, air
and water can form respective phases. That is, it can be regarded
that the water phase and the air phase are separated.
[0058] The heat transport medium may be any of gas, liquid, and
solid. Heat transport media different in specific heat per unit
volume can be appropriately selected for use.
[0059] In this case, it is preferable to use a combination with a
large difference in specific heat per unit volume. For instance,
combinations such as gas-liquid, solid-liquid, and solid-gas can be
used.
[0060] A heat transport medium of gas can be e.g. air or nitrogen
gas. A heat transport medium of gas can reduce pressure loss during
transportation. A heat transport medium of liquid can be e.g.
water, an oil-based medium such as mineral oil and silicone, or a
solvent-based medium such as alcohols (e.g., ethylene glycol).
[0061] In this case, water has the highest specific heat and is
inexpensive. However, water may freeze in the temperature region of
0.degree. C. or less. Thus, it is preferable to use e.g. an
oil-based medium, a solvent-based medium, a mixed liquid of water
and an oil-based medium, or a mixed liquid of water and a
solvent-based medium. Depending on the operating temperature region
of the magnetic refrigeration system 100, the liquid can be
appropriately changed in kind and mixing ratio.
[0062] A heat transport medium of solid can be e.g. resin, metal,
or inorganic material such as ceramic.
[0063] In this case, for instance, the heat transport medium of
solid can be integrally configured, or a granular solid aggregate
can be used as the heat transport medium. However, the integrally
configured heat transport medium of solid can suppress mixing with
a different heat transport medium.
[0064] The heat transport medium 8 and the heat transport medium 9
can have either the same configuration or different
configurations.
[0065] The transport section 10 circulates the heat transport
medium 8 in the closed loop channel formed from the heat exchange
section 1, the high temperature side heat exchange section 4, the
transport section 10, and the piping 6. More specifically, the heat
transport medium 80a and the heat transport medium 80b are
sequentially fed into the heat exchange section 1. The heat
transport medium 80a and the heat transport medium 80b heated in
the heat exchange section 1 are sent to the high temperature side
heat exchange section 4. The heat transport medium 80a and the heat
transport medium 80b heat-exchanged with the heat exchange target,
not shown, in the high temperature side heat exchange section 4 are
sent again to the heat exchange section 1.
[0066] The transport section 11 circulates the heat transport
medium 9 in the closed loop channel formed from the heat exchange
section 1, the low temperature side heat exchange section 5, the
transport section 11, and the piping 7. More specifically, the heat
transport medium 90a and the heat transport medium 90b are
sequentially fed into the heat exchange section 1. The heat
transport medium 90a and the heat transport medium 90b subjected to
heat absorption in the heat exchange section 1 are sent to the low
temperature side heat exchange section 5. The heat transport medium
90a and the heat transport medium 90b heat-exchanged with the heat
exchange target, not shown, in the low temperature side heat
exchange section 5 are sent again to the heat exchange section
1.
[0067] The transport section 10, 11 can be e.g. any of various
pumps.
[0068] The control section 24 controls the operation of the moving
section 3, the transport section 10, and the transport section
11.
[0069] More specifically, when the heat exchange section 1 is fed
with the heat transport medium 80a and the heat transport medium
90b, the control section 24 controls the operation of the moving
section 3, the transport section 10, and the transport section 11
so as to apply a magnetic field to the heat exchange section 1.
When the heat exchange section 1 is fed with the heat transport
medium 80b and the heat transport medium 90a, the control section
24 controls the operation of the moving section 3, the transport
section 10, and the transport section 11 so as to remove the
magnetic field applied to the heat exchange section 1.
[0070] For instance, in performing heat generation, the transport
section 10 is controlled to feed the heat exchange section 1 with
the heat transport medium 80a having a higher specific heat per
unit volume than the heat transport medium 80b. Furthermore, the
moving section 3 constituting the magnetic field changing section
is controlled to apply a magnetic field to the heat exchange
section 1.
[0071] For instance, in performing heat absorption, the transport
section 11 is controlled to feed the heat exchange section 1 with
the heat transport medium 90a having a higher specific heat per
unit volume than the heat transport medium 90b. Furthermore, the
moving section 3 constituting the magnetic field changing section
is controlled to remove the magnetic field from the heat exchange
section 1.
[0072] The relationship between application of the magnetic field
and removal of the magnetic field in the heat exchange section 1
and the heat transport media different in specific heat per unit
volume will be described later.
[0073] Next, the function of the magnetic refrigeration system 100
is illustrated.
[0074] FIG. 3 is a flow chart for illustrating the function of the
heat exchange section according to the first embodiment.
[0075] FIGS. 4A and 4B are schematic sectional views for
illustrating heat exchange in the heat exchange section according
to the first embodiment. More specifically, FIG. 4A shows the case
of applying a magnetic field to the heat exchange section 1. FIG.
4B shows the case of removing the magnetic field applied to the
heat exchange section.
[0076] First, as shown in FIG. 3, the heat exchange section 1 is
fed with the heat transport medium 80a and the heat transport
medium 90b (step S1).
[0077] More specifically, the control section 24 controls the
transport section 10 to feed the heat transport medium 80a into the
region 12 of the heat exchange section 1. Furthermore, the control
section 24 controls the transport section 11 to feed the heat
transport medium 90b into the region 13 of the heat exchange
section 1.
[0078] Next, the control section 24 controls the moving section 3
to move the magnetic field generating section 2 to the position 22
(ON position) for applying a magnetic field to the heat exchange
section 1 (step S2).
[0079] The state at this time is as illustrated in FIG. 4A.
[0080] When the magnetic field is applied to the heat exchange
section 1, the magnetocaloric effect material forming the region 14
generates heat. Thus, the generated heat is absorbed by the
transport medium 80a fed into the region 12 and the transport
medium 90b fed into the region 13.
[0081] Next, the control section 24 controls the transport section
10 to feed the heat transport medium 80b into the region 12 of the
heat exchange section 1. Furthermore, the control section 24
controls the transport section 11 to feed the heat transport medium
90a into the region 13 of the heat exchange section 1 (step
S3).
[0082] Thus, the transport medium 80a is ejected from the region 12
toward the high temperature side heat exchange section 4. The
transport medium 90b is ejected from the region 13 toward the low
temperature side heat exchange section 5.
[0083] Next, the control section 24 controls the moving section 3
to move the magnetic field generating section 2 to the position 23
(OFF position) for not applying a magnetic field to the heat
exchange section 1 (step S4).
[0084] The state at this time is as illustrated in FIG. 4B.
[0085] When the magnetic field applied to the heat exchange section
1 is removed, the magnetocaloric effect material forming the region
14 absorbs heat. Thus, heat is drawn from the heat transport medium
80b fed into the region 12 and the heat transport medium 90a fed
into the region 13.
[0086] After step S4, control returns to step S1.
[0087] More specifically, the control section 24 controls the
transport section 10 to feed the heat transport medium 80a into the
region 12 of the heat exchange section 1. Furthermore, the control
section 24 controls the transport section 11 to feed the heat
transport medium 90b into the region 13 of the heat exchange
section 1.
[0088] Thus, the transport medium 80b is ejected from the region 12
toward the high temperature side heat exchange section 4. The
transport medium 90a is ejected from the region 13 toward the low
temperature side heat exchange section 5.
[0089] By repeating the foregoing procedure, the heat transport
medium 8 (heat transport media 80a, 80b) is sent to the high
temperature side heat exchange section 4. The heat transport medium
9 (heat transport media 90a, 90b) is sent to the low temperature
side heat exchange section 5.
[0090] Then, for instance, heat taken out of the heat transport
medium 8 in the high temperature side heat exchange section 4 can
be used for air heating. Furthermore, for instance, heat can be
absorbed by the heat transport medium 9 in the low temperature side
heat exchange section 5 for air cooling.
[0091] Here, heat generation of the magnetocaloric effect material
by application of a magnetic field and heat absorption of the
magnetocaloric effect material by removal of the applied magnetic
field are known phenomena, and thus the description thereof is
omitted.
[0092] Next, feeding the regions 12, 13 of the heat exchange
section 1 with heat transport media different in specific heat per
unit volume is further described.
[0093] By application of a magnetic field, heat is generated by the
magnetocaloric effect material and absorbed by heat transport media
different in specific heat per unit volume. In this case, even
under the same temperature environment, more heat is absorbed by
the heat transport medium having a higher specific heat per unit
volume.
[0094] By removal of the applied magnetic field, heat is absorbed
by the magnetocaloric effect material to draw heat from heat
transport media different in specific heat per unit volume. In this
case, even under the same temperature environment, more heat is
drawn from the heat transport medium having a higher specific heat
per unit volume.
[0095] Here, in step S2, the magnetocaloric effect material
generates heat. In this step, the heat transport medium 80a having
a high specific heat per unit volume is fed into the region 12 of
the heat exchange section 1, and the heat transport medium 90b
having a low specific heat per unit volume is fed into the region
13 of the heat exchange section 1.
[0096] Thus, more heat from the magnetocaloric effect material is
absorbed by the heat transport medium 80a having a higher specific
heat per unit volume. That is, heat is selectively provided to the
heat transport medium 80a.
[0097] On the other hand, in step S4, the magnetocaloric effect
material absorbs heat. In this step, the heat transport medium 80b
having a low specific heat per unit volume is fed into the region
12 of the heat exchange section 1, and the heat transport medium
90a having a high specific heat per unit volume is fed into the
region 13 of the heat exchange section 1.
[0098] Thus, a larger amount of heat is drawn from the heat
transport medium 90b having a higher specific heat per unit volume.
That is, heat is selectively drawn from the heat transport medium
90b.
[0099] Here, in the heat transport medium 8, in step S2 in which
the magnetocaloric effect material generates heat, the heat
transport medium 80a having a high specific heat per unit volume is
fed into the region 12 of the heat exchange section 1. In step S4
in which the magnetocaloric effect material absorbs heat, the heat
transport medium 80b having a low specific heat per unit volume is
fed into the region 12 of the heat exchange section 1.
[0100] Thus, when the magnetocaloric effect material generates
heat, the amount of heat is selectively provided to the heat
transport medium 80a. On the other hand, when the magnetocaloric
effect material absorbs heat, the amount of heat drawn from the
heat transport medium 80b can be suppressed. As a result, the
generated warm heat can be efficiently sent to the high temperature
side heat exchange section 4.
[0101] In the heat transport medium 9, in step S4 in which the
magnetocaloric effect material absorbs heat, the heat transport
medium 90a having a high specific heat per unit volume is fed into
the region 13 of the heat exchange section 1. In step S2 in which
the magnetocaloric effect material generates heat, the heat
transport medium 90b having a low specific heat per unit volume is
fed into the region 13 of the heat exchange section 1.
[0102] Thus, when the magnetocaloric effect material absorbs heat,
the amount of heat is selectively drawn from the heat transport
medium 90a. When the magnetocaloric effect material generates heat,
the amount of heat absorbed from the heat transport medium 90b can
be suppressed. As a result, the generated cool heat can be
efficiently sent to the low temperature side heat exchange section
5.
Second Embodiment
[0103] FIG. 5 is a schematic view for illustrating a magnetic
refrigeration system according to a second embodiment.
[0104] As shown in FIG. 5, the magnetic refrigeration system 101
includes a heat exchange section 1, a magnetic field generating
section 2, a moving section 3, a high temperature side heat
exchange section 4, a low temperature side heat exchange section 5,
a piping 6, a piping 7, a heat transport medium 8, a heat transport
medium 9, a transport section 10, a transport section 11, a high
temperature side ejecting section 16, a low temperature side
ejecting section 17, a feeding section 18, and a control section
34.
[0105] As in the magnetic refrigeration system 100 described above,
the high temperature side heat exchange section 4 performs heat
exchange between the heat transport medium 8 heated in the heat
exchange section 1 and a heat exchange target, not shown. The low
temperature side heat exchange section 5 performs heat exchange
between the heat transport medium 9 subjected to heat absorption in
the heat exchange section 1 and a heat exchange target, not
shown.
[0106] In this case, if the heat transport media 8, 9 stagnate
inside the high temperature side heat exchange section 4 and the
low temperature side heat exchange section 5, the heat exchange
efficiency may decrease.
[0107] In the following description, as an example, it is assumed
that the heat transport medium 80a, 90a is liquid (e.g., water) and
the heat transport medium 80b, 90b is gas (e.g., air).
[0108] For instance, the heat transport medium 80b, 90b being a gas
may stagnate inside the high temperature side heat exchange section
4 and the low temperature side heat exchange section 5. This
hampers the inflow of the heat transport medium 80a, 90a and may
decrease the heat exchange efficiency in the high temperature side
heat exchange section 4 and the low temperature side heat exchange
section 5. Furthermore, if the temperature of the heat transport
medium 80a is increased by heating, part of the heat transport
medium 80a being a liquid is evaporated. Then, the evaporated gas
may coexist (suspend) in the heat transport medium 80a. In such
cases, the phases of the heat transport medium 80a and the heat
transport medium 80b may be mixed. Furthermore, the heat exchange
efficiency in the high temperature side heat exchange section 4 may
decrease.
[0109] Thus, in this embodiment, a high temperature side ejecting
section 16 and a low temperature side ejecting section 17 are
provided so that the gas having low contribution to heat exchange
is ejected into the atmosphere before flowing into the high
temperature side heat exchange section 4 and the low temperature
side heat exchange section 5.
[0110] More specifically, on the inflow side (upstream side) of the
high temperature side heat exchange section 4, a high temperature
side ejecting section 16 for ejecting the heat transport medium 80b
is provided. On the inflow side (upstream side) of the low
temperature side heat exchange section 5, a low temperature side
ejecting section 17 for ejecting the heat transport medium 90b is
provided.
[0111] The high temperature side ejecting section 16 and the low
temperature side ejecting section 17 can be e.g. a gas-liquid
separator including a gas-liquid separation membrane.
[0112] By providing a high temperature side ejecting section 16 and
a low temperature side ejecting section 17, the above problem can
be solved.
[0113] The high temperature side ejecting section 16 and the low
temperature side ejecting section 17 illustrated in FIG. 5 are
provided separately from the high temperature side heat exchange
section 4 and the low temperature side heat exchange section 5.
However, the embodiment is not limited thereto. For instance, the
high temperature side ejecting section 16 may be provided inside
the high temperature side heat exchange section 4. The low
temperature side ejecting section 17 may be provided inside the low
temperature side heat exchange section 5.
[0114] Furthermore, the heat transport medium 90a has a low risk of
coexistence of evaporated gas. Thus, the low temperature side
ejecting section 17 may be omitted to provide only the high
temperature side ejecting section 16.
[0115] The feeding section 18 reconfigures the heat transport media
8, 9.
[0116] For instance, the feeding section 18 allows the heat
transport medium 80b ejected by the high temperature side ejecting
section 16 to be formed again on the outflow side (downstream side)
of the high temperature side heat exchange section 4. Furthermore,
the feeding section 18 allows the heat transport medium 90b ejected
by the low temperature side ejecting section 17 to be formed again
on the outflow side (downstream side) of the low temperature side
heat exchange section 5.
[0117] In the case described above, after the heat transport medium
80a passes through the high temperature side heat exchange section
4, the feeding section 18 feeds a prescribed amount of heat
transport medium 80b into the piping 6 to reconfigure the heat
transport medium 8 composed of the heat transport medium 80a and
the heat transport medium 80b. After the heat transport medium 90a
passes through the low temperature side heat exchange section 5,
the feeding section 18 feeds a prescribed amount of heat transport
medium 90b into the piping 7 to reconfigure the heat transport
medium 9 composed of the heat transport medium 90a and the heat
transport medium 90b.
[0118] More specifically, the feeding section 18 feeds the heat
transport medium 80b in the same amount as the heat transport
medium 80b ejected by the high temperature side ejecting section
16. The feeding section 18 feeds the heat transport medium 90b in
the same amount as the heat transport medium 90b ejected by the low
temperature side ejecting section 17.
[0119] The control section 34 controls the operation of the moving
section 3, the transport section 10, the transport section 11, and
the feeding section 18.
[0120] More specifically, when the heat exchange section 1 is fed
with the heat transport medium 80a and the heat transport medium
90b, the control section 34 controls the operation of the moving
section 3, the transport section 10, and the transport section 11
so as to apply a magnetic field to the heat exchange section 1.
When the heat exchange section 1 is fed with the heat transport
medium 80b and the heat transport medium 90a, the control section
34 controls the operation of the moving section 3, the transport
section 10, and the transport section 11 so as to remove the
magnetic field applied to the heat exchange section 1. Furthermore,
the control section 34 controls the operation of the feeding
section 18 so as to reconfigure the heat transport media 8, 9.
[0121] Next, the function of the magnetic refrigeration system 101
is illustrated.
[0122] The function of the heat exchange section 1 can be made
similar to that illustrated in FIG. 3.
[0123] More specifically, when a magnetic field is applied to the
heat exchange section 1 to cause heat generation, the region 12 is
fed with the heat transport medium 80a having a high specific heat
per unit volume, and the region 13 is fed with the heat transport
medium 90b having a low specific heat per unit volume.
[0124] As described above, the heat transport medium 90b has a
lower specific heat per unit volume. Thus, under the same
temperature environment, a larger amount of heat generated is
absorbed into the heat transport medium 80a having a higher
specific heat per unit volume. Accordingly, the amount of heat due
to heat generation is selectively absorbed into the heat transport
medium 80a. Thus, the heat transport medium 80a is efficiently
heated.
[0125] On the other hand, when the magnetic field applied to the
heat exchange section 1 is removed to cause heat absorption, the
region 12 is fed with the heat transport medium 80b having a low
specific heat per unit volume, and the region 13 is fed with the
heat transport medium 90a having a high specific heat per unit
volume.
[0126] As described above, the heat transport medium 80b has a
lower specific heat per unit volume. Thus, under the same
temperature environment, a larger amount of heat is drawn to the
magnetocaloric effect material from the heat transport medium 90a
having a higher specific heat per unit volume. Accordingly, heat is
selectively drawn to the magnetocaloric effect material from the
heat transport medium 90a. Thus, the heat transport medium 90a is
efficiently cooled.
[0127] Then, the heat transport medium 8 (heat transport media 80a,
80b) is sent to the high temperature side heat exchange section 4.
The heat transport medium 9 (heat transport media 90a, 90b) is sent
to the low temperature side heat exchange section 5.
[0128] In this case, by the high temperature side ejecting section
16, the heat transport medium 80b is removed before flowing into
the high temperature side heat exchange section 4. By the low
temperature side ejecting section 17, the heat transport medium 90b
is removed before flowing into the low temperature side heat
exchange section 5.
[0129] In the high temperature side heat exchange section 4, for
instance, heat taken out of the heat transport medium 80a can be
used for air heating. In the low temperature side heat exchange
section 5, for instance, heat can be absorbed by the heat transport
medium 90a for air cooling.
[0130] Furthermore, the feeding section 18 reconfigures the heat
transport medium 8 on the outflow side (downstream side) of the
high temperature side heat exchange section 4. The feeding section
18 reconfigures the heat transport medium 9 on the outflow side
(downstream side) of the low temperature side heat exchange section
5.
Third Embodiment
[0131] FIGS. 6A and 6B are schematic views for illustrating
magnetic refrigeration systems according to a third embodiment.
More specifically, FIG. 6A is a schematic view for illustrating a
magnetic refrigeration system 100a using only heat generation of
the magnetocaloric effect material. FIG. 6B is a schematic view for
illustrating a magnetic refrigeration system 100b using only heat
absorption of the magnetocaloric effect material.
[0132] As shown in FIG. 6A, the magnetic refrigeration system 100a
includes a heat exchange section 1, a magnetic field generating
section 2, a moving section 3, a high temperature side heat
exchange section 4, a piping 6, a heat transport medium 8, a
transport section 10, and a control section 24a.
[0133] The control section 24a controls the operation of the moving
section 3 and the transport section 10.
[0134] More specifically, when the heat exchange section 1 is fed
with the heat transport medium 80a, the control section 24a
controls the operation of the moving section 3 and the transport
section 10 so as to apply a magnetic field to the heat exchange
section 1. When the heat exchange section 1 is fed with the heat
transport medium 80b, the control section 24a controls the
operation of the moving section 3 and the transport section 10 so
as to remove the magnetic field applied to the heat exchange
section 1
[0135] Thus, when the magnetocaloric effect material generates
heat, heat can be efficiently absorbed by the heat transport medium
80a having a high specific heat per unit volume. When the
magnetocaloric effect material absorbs heat, heat drawn to the
magnetocaloric effect material by the heat transport medium 80b
having a low specific heat per unit volume can be suppressed. As a
result, the heat exchange efficiency can be improved.
[0136] As shown in FIG. 6B, the magnetic refrigeration system 100b
includes a heat exchange section 1, a magnetic field generating
section 2, a moving section 3, a low temperature side heat exchange
section 5, a piping 7, a heat transport medium 9, a transport
section 11, and a control section 24b.
[0137] The control section 24b controls the operation of the moving
section 3 and the transport section 11.
[0138] More specifically, when the heat exchange section 1 is fed
with the heat transport medium 90b, the control section 24b
controls the operation of the moving section 3 and the transport
section 11 so as to apply a magnetic field to the heat exchange
section 1. When the heat exchange section 1 is fed with the heat
transport medium 90a, the control section 24b controls the
operation of the moving section 3 and the transport section 11 so
as to remove the magnetic field applied to the heat exchange
section 1.
[0139] Thus, when the magnetocaloric effect material generates
heat, heat absorbed by the heat transport medium 90b having a low
specific heat per unit volume is suppressed. When the
magnetocaloric effect material absorbs heat, heat is efficiently
drawn to the magnetocaloric effect material by the heat transport
medium 90a having a high specific heat per unit volume. As a
result, the heat exchange efficiency can be improved.
[0140] Here, the magnetic refrigeration system 100a can also
include a high temperature side ejecting section 16 and a feeding
section 18 illustrated in FIG. 5. The magnetic refrigeration system
100b can also include a low temperature side ejecting section 17
and a feeding section 18 illustrated in FIG. 5.
[0141] In the embodiments illustrated above, respective phases of
heat transport media different in specific heat per unit volume are
formed. The phases of heat transport media thus formed are
sequentially fed into the heat exchange section 1. However, the
embodiments are not limited thereto.
[0142] For instance, by using a switching valve and the like, the
heat transport medium fed into the heat exchange section 1 may be
switched so that heat transport media different in specific heat
per unit volume are sequentially fed into the heat exchange section
1.
[0143] That is, it is only necessary that heat transport media
different in specific heat per unit volume be sequentially fed into
the heat exchange section 1.
Practical Example
[0144] Next, a comparison with an AMR magnetic refrigeration system
according to a comparative example is described. The comparison is
intended to investigate the effect of the magnetic refrigeration
system according to the embodiment.
Practical Example 1
[0145] FIGS. 7A and 7B are schematic sectional views for
illustrating the heat exchange section 1 of the magnetic
refrigeration system according to the embodiment. More
specifically, FIG. 7A shows the case of applying a magnetic field.
FIG. 7B shows the case of removing the applied magnetic field.
[0146] The region 14 of the heat exchange section 1 illustrated in
FIGS. 7A and 7B is formed from a Gd (gadolinium) plate. The weight
of the Gd plate was set to 100 g, the z-direction thickness was set
to 3 mm, and the x-direction length was set to 115 mm. As the
region 12 and the region 13, linear channels each having a
z-direction depth of 3 mm, a y-direction width of 2 mm, and an
x-direction length of 115 mm were formed on the Gd plate. In the
region 12 and the piping 6 and in the region 13 and the piping 7, a
water phase and an air phase were alternately formed. Furthermore,
the water phase and the air phase were made equal in volume ratio.
The occupied volume per phase was made equal to the channel
volume.
[0147] First, as shown in FIG. 7A, the water phase was placed in
the region 12, and the air phase was placed in the region 13. Then,
by applying a magnetic field to the heat exchange section 1, the
magnetocaloric effect material (Gd (gadolinium)) was caused to
generate heat.
[0148] Next, as shown in FIG. 7B, the water phase was ejected from
the region 12 so that an air phase was placed in the region 12.
Furthermore, the air phase was ejected from the region 13 so that a
water phase was placed in the region 13. Then, by removing the
magnetic field applied to the heat exchange section 1, the
magnetocaloric effect material is caused to absorb heat.
[0149] The foregoing process was taken as one cycle. During one
cycle, the temperature T.sub.H of air and water flowing through the
region 12 was measured by a thermocouple in contact with the air
and water in the region 12. From the temperature change, the weight
of the water phase, and the weight of the air phase in this
measurement, the amount of heat absorption was determined, and the
heat transport efficiency was calculated.
[0150] In this case, the heat transport efficiency was defined by
equation (1).
Heat transport efficiency=(Amount of heat absorption of
water+Amount of heat absorption of air in region 12)/Theoretical
amount of heat generation from Gd (gadolinium) 100 g during
magnetic field application of one cycle (1)
[0151] Here, the amount of heat absorption of water is given by
specific heat of water (4.2 kJ/kg/K).times.density of water (1000
kg/m.sup.3).times.volume of region 12 (m.sup.3).times.maximum
temperature increase of water (.DELTA.T.sub.H2O). The amount of
heat absorption of air is given by specific heat of air (1
kJ/kg/K).times.density of air (1.29 kg/m.sup.3).times.volume of
region 12 (m.sup.3).times.temperature increase of air
(.DELTA.T.sub.air). The theoretical amount of heat generation from
Gd 100 g during magnetic field application of one cycle (QGd) was
determined by QGd=T (298 K).times.magnetic entropy change
(.DELTA.S=2.5 kJ/kg/K).times.0.1 (kg-Gd).
Comparative Example 1
[0152] FIG. 8 is a schematic sectional view for illustrating a heat
exchange section 51 of the AMR magnetic refrigeration system
according to the comparative example.
[0153] First, 100 g of Gd (gadolinium) particles having the
magnetocaloric effect with a diameter of 1 mm were packed in a
cylindrical container 52 having an inner diameter of 15 mm and a
length of 115 mm with a packing ratio of 60%. At the end portion, a
partition plate 53 made of a metal mesh was provided. Then, the
remaining space inside the heat exchange section 51 was filled with
water to produce a heat exchange section 51.
[0154] To the heat exchange section 51, a magnetic field having the
same intensity as that of Practical example 1 was applied to cause
the Gd (gadolinium) particles to generate heat.
[0155] Then, the partition plate 53 was moved +1 cm in the X-axis
direction to move the water. The moving speed was set to 0.4
cm/s.
[0156] Next, the applied magnetic field was removed. After the
removal, the partition plate 53 was moved -1 cm in the X-axis
direction to move the water. The moving speed was set to 0.4
cm/s.
[0157] The foregoing process was taken as one cycle. During one
cycle, the temporal change of the temperature of water was measured
by a thermocouple placed in the water. From the temperature change
and the weight of water, the heat transport efficiency during heat
generation was calculated.
[0158] In this case, the heat transport efficiency was calculated
using the following equation (2).
Heat transport efficiency=Amount of heat absorption of
water/Theoretical amount of heat generation from Gd 100 g during
magnetic field application of one cycle (2)
[0159] Here, the amount of heat absorption of water is given by
specific heat of water (4.2 kJ/kg/K).times.density of water (1000
kg/m.sup.3).times.filling volume of water in cylindrical container
52 (m.sup.3).times.maximum temperature increase of water
(.DELTA.T.sub.H2O). The theoretical amount of heat generation from
Gd 100 g during magnetic field application of one cycle (QGd) was
determined by QGd=T (298 K).times.magnetic entropy change
(.DELTA.S=2.5 kJ/kg/K).times.0.1 (kg-Gd).
[0160] FIG. 9 is a graph showing the comparison between the heat
transport efficiency in Practical example 1 and the heat transport
efficiency in Comparative example 1.
[0161] With regard to the temperature measurement, the initial
temperature of water and the initial temperature of air were set to
25.degree. C., equal to the ambient temperature.
[0162] As shown in FIG. 9, the heat transport efficiency in
Practical example 1 was 50%, and the heat transport efficiency in
Comparative example 1 was 2.6%. That is, it was confirmed that
Practical example 1 achieved a significantly higher heat transport
efficiency than Comparative example 1.
[0163] The embodiments described above can realize a magnetic
refrigeration system capable of improving the heat transport
efficiency.
[0164] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions. Moreover, above-mentioned embodiments can be combined
mutually and can be carried out.
[0165] For instance, the shape, dimension, material, layout and the
like of various components in the magnetic refrigeration system
100, the magnetic refrigeration system 101, the magnetic
refrigeration system 100a, the magnetic refrigeration system 100b
and the like are not limited to those illustrated above, but can be
appropriately modified.
* * * * *