U.S. patent application number 11/533163 was filed with the patent office on 2007-06-07 for heat transporting apparatus.
Invention is credited to Katsumi HISANO, Hideo IWASAKI, Akihiro KASAHARA, Tadahiko KOBAYASHI, Akihiro KOGA, Akiko SAITO, Takuya TAKAHASHI.
Application Number | 20070125095 11/533163 |
Document ID | / |
Family ID | 38117360 |
Filed Date | 2007-06-07 |
United States Patent
Application |
20070125095 |
Kind Code |
A1 |
IWASAKI; Hideo ; et
al. |
June 7, 2007 |
HEAT TRANSPORTING APPARATUS
Abstract
In a heat transporting apparatus, a cylinder is filled with a
refrigerant and pistons are arranged in the cylinder, which
compress and expand the refrigerant in the cylinder. A magnet unit
is movably provided around the cylinder to apply a magnetic field
to the cylinder, which is alternately increased and decreased in
accordance with a movement of the magnet unit. A thermal
accumulator is received in the cylinder, which produces heat
depending on one of the increasing and decreasing of the magnetic
field at the compression of the refrigerant, and absorbs heat
depending on the other of the increasing and decreasing of the
magnetic field at the expansion of the refrigerant. Heat exchangers
are located in the cylinder, which radiates the heat from the
refrigerant and thermal accumulator to an exterior of the
apparatus, and absorbs external heat and transfers the heat to the
refrigerant and thermal accumulator.
Inventors: |
IWASAKI; Hideo;
(Kawasaki-shi, JP) ; KASAHARA; Akihiro;
(Sambu-gun, JP) ; HISANO; Katsumi; (Matsudo-shi,
JP) ; KOGA; Akihiro; (Tokyo, JP) ; SAITO;
Akiko; (Kawasaki-shi, JP) ; KOBAYASHI; Tadahiko;
(Yokohama-shi, JP) ; TAKAHASHI; Takuya; (Tokyo,
JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
38117360 |
Appl. No.: |
11/533163 |
Filed: |
September 19, 2006 |
Current U.S.
Class: |
62/3.1 |
Current CPC
Class: |
F25B 21/00 20130101;
Y02B 30/00 20130101; F25B 2321/0022 20130101 |
Class at
Publication: |
062/003.1 |
International
Class: |
F25B 21/00 20060101
F25B021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2005 |
JP |
2005-352242 |
Claims
1. A heat transporting apparatus, comprising: a container filled
with a refrigerant; an operation unit which compresses the
refrigerant to produce heat and expands the refrigerant to absorb
heat in the container, alternately; a generating unit configured to
generate a magnetic field which is increased and decreased,
alternately; a thermal accumulator received in the container, to
which the magnetic field is applied from the generating unit, and
which produces heat depending on one of the increasing and
decreasing of the magnetic field at the time of compression of the
refrigerant and absorbs heat depending on the other of the
increasing and decreasing of the magnetic field at the time of
expansion of the refrigerant; and first and second heat transfer
units, the first heat transfer unit transferring the heat produced
in the refrigerant and the thermal accumulator to the outside of
the apparatus, and the second heat transfer unit transferring
external heat to the refrigerant and the magnetic unit.
2. The apparatus according to claim 1, wherein the thermal
accumulator includes a positive magnetic material which produces
the heat depending on the increasing of the magnetic field and
which absorbs the heat depending on the decreasing of the magnetic
field.
3. The apparatus according to claim 1, wherein the thermal
accumulator includes a negative magnetic material which produces
the heat depending on the decreasing of the magnetic field and
which absorbs the heat depending on the increasing of the magnetic
field.
4. The apparatus according to claim 1, wherein the thermal
accumulator includes first and second magnetic segments arranged in
series with a gap in the container, the first magnetic segment
includes a positive magnetic material which produces the heat
depending on the increasing of the magnetic field and which absorbs
the heat depending on the decreasing of the magnetic field, and the
second magnetic segment includes a negative magnetic material which
produces the heat depending on the decreasing of the magnetic field
and which absorbs the heat depending on the increasing of the
magnetic field.
5. The apparatus according to claim 1, wherein the generating unit
includes a magnet for generating the magnetic field and a mechanism
configured to move the magnet along the container to apply the
magnetic field to the magnetic unit and remove the magnetic field
from the magnetic unit, alternately, in accordance with the
compression and expansion of the refrigerant.
6. A heat transporting apparatus comprising: a cylindrical
container provided with compression and expansion chambers
communicating with each other and filled with a refrigerant; a
compression piston received in the cylindrical container, which
compresses the refrigerant in the expansion chamber and an
expansion piston which expands the refrigerant in the expansion
chamber; a generating unit configured to generate a magnetic field
which is increased and decreased, alternately; a thermal
accumulator received in the cylindrical container, to which the
magnetic field is applied, and which produces heat depending on one
of the increasing and decreasing of the magnetic field at the time
of compression of the refrigerant and absorbs heat depending on the
other of the increasing and decreasing of the magnetic field at the
time of expansion of the refrigerant; and first and second heat
transfer units, the first heat transfer unit transferring the heat
produced in the refrigerant and the magnetic unit to the outside of
the apparatus, and the second heat transfer unit transferring
external heat to the refrigerant and the magnetic unit.
7. The apparatus according to claim 6, wherein the thermal
accumulator includes a positive magnetic material which produces
the heat depending on the increasing of the magnetic field and
which absorbs the heat depending on the decreasing of the magnetic
field.
8. The apparatus according to claim 6, wherein the thermal
accumulator includes a negative magnetic material which produces
the heat depending on the decreasing of the magnetic field and
which absorbs the heat depending on the increasing of the magnetic
field.
9. The apparatus according to claim 6, wherein the thermal
accumulator includes first and second magnetic segments arranged in
series with a gap in the container, the first magnetic segment
includes a positive magnetic material which produces the heat
depending on the increasing of the magnetic field and which absorbs
the heat depending on the decreasing of the magnetic field, and the
second magnetic segment includes a negative magnetic material which
produces the heat depending on the decreasing of the magnetic field
and which absorbs the heat depending on the increasing of the
magnetic field.
10. The apparatus according to claim 6, wherein the generating unit
includes a magnet for generating the magnetic field and a mechanism
configured to move the magnet along the container to apply the
magnetic field to the thermal accumulator and remove the magnetic
field from the thermal accumulator, alternately, in accordance with
the compression and expansion of the refrigerant.
11. The apparatus according to claim 6, wherein the generating unit
includes an electric magnet which is alternatively energized and
de-energized to increase and decrease the magnetic field.
12. The apparatus according to claim 6, wherein the generating unit
includes a Halbach magnet.
13. A heat transporting apparatus comprising: a cylindrical
container filled with a refrigerant; pistons received in the
cylindrical container, which compress and expand the refrigerant; a
generating unit configured to generate a magnetic field which is
increased and decreased, alternately; a thermal accumulator
received in the cylindrical container, to which the magnetic field
is applied, and which produces heat depending on one of the
increasing and decreasing of the magnetic field at the time of
compression of the refrigerant and absorbs heat depending on the
other of the increasing and decreasing of the magnetic field at the
time of expansion of the refrigerant; and first and second heat
transfer units, the first heat transfer unit transferring the heat
produced in the refrigerant and the thermal accumulator to the
outside of the apparatus, and the second heat transfer unit
transferring external heat to the refrigerant and the thermal
accumulator.
14. The apparatus according to claim 13, wherein the thermal
accumulator includes a positive magnetic material which produces
the heat depending on the increasing of the magnetic field and
which absorbs the heat depending on the decreasing of the magnetic
field.
15. The apparatus according to claim 13, wherein the thermal
accumulator includes a negative magnetic material which produces
the heat depending on the decreasing of the magnetic field and
which absorbs the heat depending on the increasing of the magnetic
field.
16. The apparatus according to claim 13, wherein the thermal
accumulator includes first and second magnetic segments arranged in
series with a gap in the container, the first magnetic segment
includes a positive magnetic material which produces the heat
depending on the increasing of the magnetic field and which absorbs
the heat depending on the decreasing of the magnetic field, and the
second magnetic segment includes a negative magnetic material which
produces the heat depending on the decreasing of the magnetic field
and which absorbs the heat depending on the increasing of the
magnetic field.
17. The apparatus according to claim 13, wherein the generating
unit includes a magnet for generating the magnetic field and a
mechanism configured to move the magnet along the container to
apply the magnetic field to the magnetic unit and remove the
magnetic field from the magnetic unit, alternately, in accordance
with the compression and expansion of the refrigerant.
18. The apparatus according to claim 13, wherein the generating
unit includes an electric magnet which is alternatively energized
and de-energized to increase and decrease the magnetic field.
19. The apparatus according to claim 13, wherein the generating
unit includes a Halbach magnet.
20. The apparatus according to claim 1, wherein the thermal
accumulator includes a magnetic material magnetic unit is made of a
porous member or a bulk having communication holes.
21. The apparatus according to claim 1, wherein the thermal
accumulator comprises a magnetic material formed of different
components such that operating temperature sequentially decreases
from a higher temperature side toward a lower temperature side in
the container.
22. A refrigerator provided with the heat transporting apparatus
according to claim 1.
23. A heat pump provided with the heat transporting apparatus
according to claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from prior Japanese Patent Application No. 2005-352242,
filed Dec. 6, 2005, the entire contents of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a heat transporting
apparatus for transporting heat with utilizing a refrigerating
cycle having a refrigerant compressing and expanding processes.
[0004] 2. Description of the Related Art
[0005] Refrigerators or heat pumps have been known as apparatuses
that utilize a refrigerating cycle to transport heat. Among the
refrigerators serving as heat transporting apparatuses, Stirling
refrigerators are gathering much attention for their high energy
efficiency. The Stirling refrigerator is essentially expected to
offer a very high refrigerating efficiency. However, the Stirling
refrigerator is actually used mainly to provide very low
temperatures (which are almost equal to liquid helium temperature).
On the other hand, the Stirling refrigerator can use helium as a
refrigerant; helium is a natural refrigerant which is harmless to
human beings and which is not involved in ozone layer destruction
or global warming.
[0006] The Stirling refrigerator operates in accordance with a
Stirling refrigerating cycle including four basic processes,
isothermal compression, isovolumetric cooling, isothermal
expansion, and isovolumetric heating. To implement the Stirling
refrigerating cycle, a high- and low-temperature cylinder sections
are provided in which a refrigerant is sealed. A higher-temperature
heat exchanger, a thermal accumulator or heat storage device, and a
lower-temperature heat exchanger are disposed between the cylinder
sections. Compression and expansion of the refrigerant are repeated
in the cylinder sections to transport heat from the
lower-temperature heat exchanger to the higher-temperature heat
exchanger. Of the four basic processes of the Stirling
refrigerating cycle, the isovolumetric heating and cooling are
mainly based on the heat exchange between the heat exchanger and
the thermal accumulator. The heat radiation and absorption by the
higher- and lower-temperature heat exchangers occur during the
isothermal compression and expansion processes.
[0007] However, the efficiency of the Stirling refrigerating cycle
used for the Stirling refrigerator is mainly limited by the heat
conducting performance of the higher- and lower-temperature heat
exchangers and thermal accumulator. Consequently, in spite of the
theoretical high efficiency, actual apparatuses are
disadvantageously inefficient and fail to achieve the desired
performance.
[0008] Thus, to improve the performance of the refrigerator, it is
important to increase the heat exchanging efficiency during the
Stirling refrigerating cycle. To increase the heat exchanging
efficiency, it is necessary to improve the heat exchanging
performance of the higher- and lower-temperature heat exchangers
and thermal accumulator.
BRIEF SUMMARY OF THE INVENTION
[0009] According to an aspect of the present invention, there is
provided a heat transfer apparatus comprising:
[0010] a container filled with a refrigerant;
[0011] an operation unit which compresses the refrigerant to
produce heat and expands the refrigerant to absorb heat in the
container, alternately;
[0012] a generating unit configured to generate a magnetic field
which is increased and decreased, alternately;
[0013] a thermal accumulator received in the container, to which
the magnetic field is applied, and which produces heat depending on
one of the increasing and decreasing of the magnetic field at the
time of compression of the refrigerant and absorbs heat depending
on the other of the increasing and decreasing of the magnetic field
at the time of expansion of the refrigerant; and
[0014] first and second heat transfer units, the first heat
transfer unit transferring the heat produced in the refrigerant and
the thermal accumulator to the outside of the apparatus, and the
second heat transfer unit transferring external heat to the
refrigerant and the thermal accumulator.
[0015] According to another aspect of the present invention, there
is provided a heat transporting apparatus comprising:
[0016] a cylindrical container provided with compression and
expansion chambers communicating with each other and filled with a
refrigerant;
[0017] a compression piston received in the cylindrical container,
which compresses the refrigerant in the expansion chamber and an
expansion piston which expands the refrigerant in the expansion
chamber;
[0018] a generating unit configured to generate a magnetic field
which is increased and decreased, alternately;
[0019] a thermal accumulator received in the cylindrical container,
to which the magnetic field is applied, and which produces heat
depending on one of the increasing and decreasing of the magnetic
field at the time of compression of the refrigerant, and absorbs
heat depending on the other of the increasing and decreasing of the
magnetic field at the time of expansion of the refrigerant; and
[0020] first and second heat transfer units, the first heat
transfer unit transferring the heat produced in the refrigerant and
the thermal accumulator to the outside of the apparatus, and the
second heat transfer unit transferring external heat to the
refrigerant and the thermal accumulator.
[0021] According to yet another aspect of the present invention,
there is provided a heat transporting apparatus comprising:
[0022] a cylindrical container filled with a refrigerant;
[0023] pistons received in the cylindrical container, which
compress and expand the refrigerant;
[0024] a generating unit configured to generate a magnetic field
which is increased and decreased, alternately;
[0025] a thermal accumulator received in the cylindrical container,
to which the magnetic field is applied, and which produces heat
depending on one of the increasing and decreasing of the magnetic
field at the time of compression of the refrigerant and absorbs
heat depending on the other of the increasing and decreasing of the
magnetic field at the time of expansion of the refrigerant; and
[0026] first and second heat transfer units, the first heat
transfer unit transferring the heat produced in the refrigerant and
the thermal accumulator to the outside of the apparatus, and the
second heat transfer unit transferring external heat to the
refrigerant and the thermal accumulator.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0027] FIGS. 1A to 1D are schematic diagrams schematically showing
a refrigerator that is applied to a first embodiment, to describe
the basic operation and structure of the refrigerator;
[0028] FIG. 2 is a schematic diagram specifically and
three-dimensionally showing a refrigerator that is applied to a
second embodiment;
[0029] FIGS. 3A and 3B are diagrams showing the general
configuration of a magnetic material for a thermal accumulator in
the refrigerator shown in FIG. 2;
[0030] FIGS. 4A and 4B are schematic diagrams showing the general
configuration of a mechanism used in the refrigerator shown in FIG.
2 to increase or reduce the magnitude of a magnetic field;
[0031] FIGS. 5A to 5D are schematic diagrams illustrating
operations of the refrigerator shown in FIG. 2;
[0032] FIGS. 6A to 6D are schematic diagrams showing the general
configuration of a refrigerator that is applied to a third
embodiment;
[0033] FIG. 7 is a schematic diagram specifically and
three-dimensionally showing a refrigerator that is applied to a
fourth embodiment;
[0034] FIGS. 8A and 8B are schematic diagrams illustrating
operations of the refrigerator shown in FIG. 7;
[0035] FIGS. 9A and 9B are schematic diagrams showing the general
configuration of a refrigerator that is applied to a fifth
embodiment;
[0036] FIG. 10 is a schematic diagram showing the general
configuration of a refrigerator that is applied to a sixth
embodiment; and
[0037] FIGS. 11A and 11B are schematic diagrams illustrating
operations of the refrigerator shown in FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
[0038] With reference to the drawings, description will be given of
heat transporting apparatuses according to embodiments of the
present invention.
FIRST EMBODIMENT
[0039] FIGS. 1A to 1D show a basic configuration of a heat
transporting apparatus such as a refrigerator, which utilizes a
Stirling refrigerating cycle.
[0040] In FIG. 1, reference numeral 1 denotes a cylinder that is a
cylindrical container. The cylinder 1 is open at its opposite ends
and is filled with a gas refrigerant, for example, helium or
nitrogen. The cylinder 1 has a heat storage device 2 in the center
of its hollow portion; the heat storage device 2 serves as a
thermal accumulator. The heat storage device 2 is composed of a
magnetic material 3 having its temperature changed in response to
an increase or decrease in the magnitude of a magnetic field. In
this embodiment, the magnetic material 3 is a positive one, for
example, a GD-based material, which has its temperature raised
(heat generation) in response to an increase in the magnitude of
the magnetic field, while having its temperature lowered (heat
absorption) in response to a decrease in the magnitude of the
magnetic field.
[0041] Inside the cylinder 1, a higher-temperature heat exchanger 4
is placed in proximity to one end of the heat storage device 2. A
lower-temperature heat exchanger 5 is placed in proximity to the
other end of the heat storage device 2. The higher-temperature heat
exchanger 4 radiates heat from the refrigerant and heat storage
device 2 to the exterior of the apparatus. The lower-temperature
heat exchanger 5 absorbs external heat on the basis of heat
absorption by the refrigerant and heat storage device 2.
[0042] A compression piston 6 is provided in an opening of the
cylinder 1 which is closer to the higher-temperature heat exchanger
4. An expansion piston 7 is provided in an opening of the cylinder
1 which is closer to the lower-temperature heat exchanger 5. The
compression piston 6 and expansion piston 7 constitute an operation
unit. The compression piston 6 moves in the direction of arrow A
shown in FIG. 1A to compress a refrigerant inside the cylinder 1.
The expansion piston 7 moves in the direction of arrow C shown in
FIG. 1C to compress the refrigerant inside the cylinder
[0043] A mechanism 8 for generating a magnetic field and increasing
and reducing the magnetic field is placed outside the cylinder 1
around the periphery of the heat storage device 2. The magnetic
field increasing and reducing mechanism 8 increases and reduces the
magnitude of a magnetic field that is applied to the magnetic
material 3 in the heat storage device 2. The magnetic field
increasing and reducing mechanism 8 is not limited to a particular
one shown in FIGS. 1A to 1D. The mechanism may be modified or
altered to various units or apparatuses that provide a function for
increasing and reducing the magnitude of a magnetic field that is
applied to the magnetic material 3. The magnetic field increasing
and reducing mechanism 8 may be an electromagnet that can be turned
on and off, or a magnetic field generating unit, for example, a
permanent magnet.
[0044] Now, description will be given of the operation of the
refrigerator configured as described above.
[0045] First, the compression piston 6 is moved in a direction A,
that is, from the left to right of the figure, to compress the
refrigerant in the cylinder 1 as shown in FIG. 1A. During the
compression process, actuation of the higher-temperature heat
exchanger 4 radiates heat generated from the refrigerant by
compression, in the direction of arrow B in FIG. 1A to the exterior
of the apparatus via the higher-temperature heat exchanger 4. An
isothermal refrigerant compressing process is thus executed.
Simultaneously with the compression of the refrigerant, the
magnetic field increasing and reducing mechanism 8 applies a
magnetic field to the heat storage device 2. Here, the heat storage
device 2 is composed of the magnetic material 3 having its
temperature changed in response to an increase or decrease in the
magnitude of a magnetic field. However, this embodiment uses a
positive magnetic material which has its temperature raised (heat
generation) in response to an increase in the magnitude of the
magnetic field and which has its temperature lowered (heat
absorption) in response to a decrease in the magnitude of the
magnetic field. The temperature of the heat storage device 2 thus
rises. The higher-temperature heat exchanger 4 is in operation even
during the application of the magnetic field. Thus, heat generated
from the heat storage device 2 is also radiated in the direction of
arrow B to the exterior of the apparatus via the higher-temperature
heat exchanger 4. In other words, during the refrigerant
compressing process shown in FIG. 1A, not only heat from the
refrigerant but also heat generated from the magnetic material 3
can be radiated to the exterior of the apparatus via the
higher-temperature heat exchanger 4.
[0046] Then, as shown in FIG. 1B, with the volume of the cylinder 1
between the compression piston 6 and the expansion piston 7
remaining fixed, the compression piston 6 and expansion piston 7
are simultaneously moved rightward to move the refrigerant
rightward in the cylinder 1.
[0047] Then, as shown in FIG. 1C, the expansion piston 7 is moved
in a C direction, that is, from the right to left of the figure, to
expand the refrigerant in the cylinder 1. At this time, actuation
of the lower-temperature heat exchanger 5 allows the refrigerant
cooled by expansion to absorb external heat in the direction of
arrow D. An isothermal refrigerant expansion process is thus
executed. Simultaneously with the expansion of the refrigerant, the
magnetic field increasing and reducing mechanism 8 removes the
magnetic field applied to the heat storage device 2. The heat
storage device 2 is composed of a positive magnetic material that
has its temperature lowered (heat absorption) in response to a
decrease in the magnitude of a magnetic field. The temperature of
the heat storage device 2 thus lowers. The lower-temperature heat
exchanger 5 is in operation even during the decrease in
temperature. Consequently, external heat can further be absorbed
via the lower-temperature heat exchanger 5. In other words, during
the refrigerant expansion process shown in FIG. 1C, heat is
absorbed not only by the refrigerant but also by the magnetic
material 3. Under these conditions, external heat can be absorbed
via the lower-temperature heat exchanger 5.
[0048] Then, as shown in FIG. 1D, with the volume of the cylinder 1
between the compression piston 6 and the expansion piston 7
remaining fixed, the compression piston 6 and expansion piston 7
are moved leftward in the figure to move the refrigerant leftward
in the cylinder 1.
[0049] The process shown in FIGS. 1A to 1D is repeated as described
above to repeatedly execute the four basic processes, isothermal
compression, isovolumetric cooling, isothermal expansion, and
isovolumetric heating. The Stirling refrigerating cycle is thus
implemented. Specifically, repetition of the compression and
expansion processes allows the refrigerant to generate and absorb
heat. The heat storage device 2, composed of the magnetic material
3, is caused to repeat a heat generating and absorbing reactions by
increasing and reducing the magnitude of the magnetic field
simultaneously with the repeated compression and expansion
processes. This allows the higher-temperature heat exchanger 4 to
radiate heat, while allowing the lower-temperature heat exchanger 5
to absorb heat.
[0050] Accordingly, in the refrigerating cycle having the
refrigerant compression and expansion processes, the compression
process not only allows the refrigerant to generate heat but also
applies a magnetic field to the magnetic material 3 constituting
the heat storage device 2 to allow the magnetic material 3 to make
a heat generating reaction. The heat from the magnetic material 3
is radiated via the higher-temperature heat exchanger 4.
Consequently, this refrigerator can radiate more heat to the
exterior of the apparatus. The expansion process not only expands
the refrigerant to allow it to absorb heat but also removes the
magnetic field to allow the magnetic material 3 to make a heat
absorbing reaction. This enables more external heat to be absorbed
via the lower-temperature heat exchanger 5. Thus, simultaneously
with the heat generation and absorption by the refrigerant, the
heat storage device 2 composed of the magnetic material 3 is caused
to make heat generating and absorbing reactions. The present
refrigerating cycle having the compression and expansion processes
offers a drastically increased heat exchanging efficiency.
Therefore, a Stirling refrigerating cycle with a good heat
transporting capability can be implemented.
[0051] The above first embodiment repeats the four basic processes,
isothermal compression, isovolumetric cooling, isothermal
expansion, and isovolumetric heating, to implement a Stirling
refrigerating cycle. An Ericsson cycle can be implemented by
substituting isobaric processes for the two isovolumetric processes
in the Stirling refrigerating cycle. A Brayton cycle can be
implemented by substituting adiabatic processes for the compression
and expansion processes in the Stirling refrigerating cycle and
substituting isobaric processes for the two isovolumetric
processes.
SECOND EMBODIMENT
[0052] FIG. 2 is a three-dimensional cross sectional view showing a
refrigerator of a second embodiment which is realized in accordance
with the first embodiment.
[0053] In FIG. 2, reference numeral 11 denotes a cylindrical
casing. A compression cylinder 12 and an expansion cylinder 13 are
arranged in parallel inside the casing 11. Each of the compression
cylinder 12 and expansion cylinder 13 is open at one end and is
closed at the other end. The closed ends are connected together via
a communication pipe 14 that allows the interior of the compression
cylinder 12 to communicate with the interior of the expansion
cylinder 13. The compression cylinder 12 and expansion cylinder 13
are filled with a gas refrigerant, for example, helium or
nitrogen.
[0054] A heat storage device 15 is placed in the compression
cylinder 12. The heat storage device 15 is provided with a magnetic
material 16 having its temperature changed in response to an
increase or decrease in the magnitude of a magnetic field. In this
embodiment, the magnetic material 16 is a positive one, for
example, a GD-based material, which has its temperature raised
(heat generation) in response to an increase in the magnitude of
the magnetic field, while having its temperature lowered (heat
absorption) in response to a decrease in the magnitude of the
magnetic field. As the magnetic material 16, generally spherical
magnetic materials 16a of diameter about 1 mm or less may be filled
in to the heat storage device 15 to form a porous member containing
a large number of voids as shown in FIG. 3A. Alternatively, a bulk
material may be used which contains communication holes 16b which
consist of small holes and which communicate with the exterior as
shown in FIG. 3B.
[0055] A higher-temperature heat exchanger 17 is placed in
proximity to the heat storage device 15. The higher-temperature
heat exchanger 17 is placed opposite the communication pipe 14
across the heat storage device 15. The higher-temperature heat
exchanger 17 radiates heat from the refrigerant and heat storage
device 15 to the exterior of the apparatus.
[0056] A compression piston 18 is provided in the compression
cylinder 12. The compression piston 18 is inserted into the
compression cylinder 12 through its opening to compress the
refrigerant in the compression cylinder 12. A piston shaft 19 is
connected to the compression piston 18. A connecting bar 20 is
connected to the piston shaft 19 and to a flywheel 21 at a position
away from its rotating center. The connecting bar 20 thus
constitutes a crank mechanism that converts a rotating motion of
the flywheel 21 into a reciprocating motion to reciprocate the
piston shaft 19 in the direction of arrow E in FIG. 2. The flywheel
21 has its rotating center connected to a rotating shaft 221 of a
driving motor 22. The flywheel 21 is rotated at a predetermined
speed.
[0057] A lower-temperature heat exchanger 23 is placed inside the
expansion cylinder 13. The lower-temperature heat exchanger 23
absorbs external heat on the basis of heat absorption by the
refrigerant and heat storage device 15. An expansion piston 24 is
provided in the expansion cylinder 13. The expansion piston 24 is
inserted into the expansion cylinder 13 through its opening to
compress the refrigerant in the expansion cylinder 13. A piston
shaft 25 is connected to the expansion piston 24. A connecting bar
26 is connected to the piston shaft 25 and to a flywheel 27 at a
position away from its rotating center. The connecting bar 26 thus
constitutes a crank mechanism that converts a rotating motion of
the flywheel 27 into a reciprocating motion to reciprocate the
piston shaft 25 in the direction of arrow F in FIG. 2. The flywheel
27 has its rotating center connected to the rotating shaft 221 of
the driving motor 22. The flywheel 27 is rotated at a predetermined
speed.
[0058] A disk-like support plate 28 is integrally provided on the
piston shaft 19. A mechanism 30 for generating a magnetic field and
increasing and reducing the magnetic field is provided on the
support plate 28 via a support arm 29. The magnetic field
increasing and reducing mechanism 30 has a cylindrical shape with
the compression cylinder located in its hollow portion. The piston
shaft 19 reciprocates in the direction of arrow E to allow the
magnetic field increasing and reducing mechanism 30 to increase or
reduce the magnitude of a magnetic field that is applied to the
heat storage device 15.
[0059] In the refrigerator shown in FIG. 2, the connecting bar 20
is attached to the flywheel 21, located closer to the compression
piston 18, so as to rotate about 90.degree. earlier in rotation
phase than a connecting bar 26 attached to the flywheel 27, located
closer to the expansion piston 24. The connecting bars 20 and 26
are arranged so as to meet the above relationship, and the piston
shafts 19 and 25 reciprocate on the basis of this positional
relationship. This serves to implement the four basic processes,
isothermal compression, isovolumetric cooling, isothermal
expansion, and isovolumetric heating, described above and shown in
FIGS. 1A to 1D.
[0060] The magnetic field increasing and reducing mechanism 30 may
be, for example, a double cylindrical magnet called a Halbach
magnet, such as the one shown in FIGS. 4A and 4B. This double
cylindrical magnet is composed of an outer cylindrical magnet 302
and an inner cylindrical magnet 301 placed in a hollow portion of
the outer cylindrical magnet 302 at a predetermined spacing from
the magnet 302. In the cylindrical magnets 301 and 302, the
directions of magnetic anisotropy at different areas are denoted by
reference numerals 303 and 304. As shown in FIG. 4A, when the
direction of a magnetic field 305 generated in the hollow portion
by the inner cylindrical magnet 301 coincides with the direction of
a magnetic field 306 generated in the hollow portion by the outer
cylindrical magnet 302, a strong magnetic field is generated in a
space 307 in the hollow portion of the inner cylindrical magnet
301. In this state, the whole double cylindrical magnet is moved
coaxially with the compression piston 18 by the piston shaft 19.
This enables an increase or reduction in the magnitude of a
magnetic field that is applied to the heat storage device 15.
[0061] Further, a weak magnetic field can be generated in the
hollow portion of the inner cylindrical magnet 301 by making the
direction of the magnetic field 305 generated in the hollow portion
by the inner cylindrical magnet 301, opposite to the direction of
the magnetic field 306 generated in the hollow portion by the outer
cylindrical magnet 302 so that the magnetic fields 305 and 306
cancel each other, as shown in FIG. 4B. With this double
cylindrical magnet, the magnitude of the magnetic field for the
heat storage device 15 can be increased or reduced by rotating one
of the inner cylindrical magnet 301 and outer cylindrical magnet
302 in conjunction with the reciprocating motion of the piston
shaft 19 to establish the conditions shown in FIG. 4A or 4B.
[0062] FIGS. 5A to 5D are diagrams illustrating the operation of
the refrigerator configured as described above. In FIGS. 5A to 5D,
the same components as those in FIG. 2 are denoted by the same
reference numerals.
[0063] A cylinder main body 31 shown in FIGS. 5A to 5D comprises
the above compression cylinder 12 and expansion cylinder 13. The
cylinder main body 31 is filled with a refrigerant. The heat
storage device 15, higher-temperature heat exchanger 17, and
lower-temperature heat exchanger 23 are arranged inside the
cylinder main body 31; the heat storage device 15 is provided with
the magnetic material 16, which has its temperature changed in
response to an increase or decrease in the magnitude of a magnetic
field. The compression piston 18 is placed in one of the openings
of the cylinder main body 31. The expansion cylinder 24 is placed
in the other opening. The mechanism 30 is placed outside the
cylinder main body 31 to increase and reduce the magnitude of a
magnetic field that is applied to the periphery of the heat storage
device 15. The magnetic field increasing and reducing mechanism 30
is connected to piston shaft 19 of the compression piston 18 via
the support arm 29. The magnetic field increasing and reducing
mechanism 8 can reciprocate in conjunction with the compression
piston 18.
[0064] In this refrigerator, first, as shown in FIG. 5A, the
compression piston 18 is moved in the direction A, that is, from
the left to right in FIG. 5A, to compress the refrigerant in the
cylinder main body 31 (compression cylinder 12). At this time,
actuation of the higher-temperature heat exchanger 17 radiates heat
generated from the refrigerant by compression, in the direction of
arrow B in FIG. 5A to the exterior of the apparatus via the
higher-temperature heat exchanger 17. An isothermal refrigerant
compressing process is thus executed. Simultaneously with the
compression of the refrigerant, the magnetic field increasing and
reducing mechanism 30, connected to the piston shaft 19, moves, as
the compression piston 18 moves, to a position where it applies a
magnetic field to the heat storage device 15. In this case, the
heat storage device 15 has its temperature raised. This is because
the heat storage device 15 is composed of the magnetic material 16
having its temperature raised (heat generation) in response to an
increase in the magnitude of a magnetic field and lowered (heat
absorption) in response to a decrease in the magnitude of the
magnetic field. At this time, the higher-temperature heat exchanger
17 is in operation. Thus, heat generated from the heat storage
device 15 can also be radiated in the direction of arrow B in FIG.
5A to the exterior of the apparatus via the higher-temperature heat
exchanger 17. In other words, during the refrigerant compressing
process shown in FIG. 5A, not only heat from the refrigerant but
also heat generated from the magnetic material 16 can be radiated
to the exterior of the apparatus via the higher-temperature heat
exchanger 17.
[0065] Then, as shown in FIG. 5B, with the volume of the cylinder
main body 31 between the compression piston 18 and the expansion
piston 24 remaining fixed, the compression piston 18 and expansion
piston 24 are simultaneously moved rightward in FIG. 5B to move the
refrigerant rightward in the cylinder main body 31.
[0066] Then, as shown in FIG. 5C, the expansion piston 7 is moved
in a direction C, i.e., from the right to left in FIG. 5C, to
expand the refrigerant in the cylinder main body 31 (expansion
cylinder 13). At this time, actuation of the lower-temperature heat
exchanger 23 allows the refrigerant cooled by expansion to absorb
external heat in the direction of arrow D in FIG. 5C via the
lower-temperature heat exchanger 23. An isothermal refrigerant
expansion process is thus executed.
[0067] Then, as shown in FIG. 5D, with the volume of the cylinder
main body 31 between the compression piston 18 and the expansion
piston 24 remaining fixed, the compression piston 18 and expansion
piston 24 are moved leftward to move the refrigerant leftward in
the cylinder main body 31. At this time, the magnetic field
increasing and reducing mechanism 30, connected to the piston shaft
19, moves away from the heat storage device 15 as the compression
piston 18 moves. This removes the magnetic field for the heat
storage device 15. The heat storage device 15 is composed of a
positive magnetic material that has its temperature (heat
absorption) lowered in response to a decrease in the magnitude of a
magnetic field. The temperature of the heat storage device 15 thus
lowers. At this time, the lower-temperature heat exchanger 23 is in
operation. Consequently, external heat can be absorbed via the
lower-temperature heat exchanger 23. In other words, during the
refrigerant expansion process shown in FIG. 5D, heat is absorbed
not only by the refrigerant but also by the magnetic material 16.
Under these conditions, external heat can be absorbed via the
lower-temperature heat exchanger 23.
[0068] The process shown in FIGS. 5A to 5D is repeated as described
above to repeatedly execute the four basic processes, isothermal
compression, isovolumetric cooling, isothermal expansion, and
isovolumetric heating. The Stirling refrigerating cycle is thus
implemented.
[0069] Therefore, the above embodiment can produce effects similar
to those of the first embodiment. Moreover, the compression piston
18, expansion piston 24, and magnetic field increasing and reducing
mechanism 30 perform the series of operations using the driving
motor 22 as a driving source. This enables the Stirling
refrigerating cycle to be executed both automatically and stably.
Furthermore, the rotation speed of the driving motor can be
increased to achieve high-speed refrigeration.
[0070] The magnetic material 16 constituting the heat storage
device 15 is a porous member containing a large number of voids or
a bulk material containing communication holes which consist of
small holes and which communicate with the exterior. The
refrigerant can thus pass through the interior of the magnetic
material 16. This makes it possible to increase the contact area
between the magnetic material 16 and the refrigerant as well as the
rate of heat transfer between the magnetic material 16 and the
refrigerant. The magnetic material 16 and the refrigerant can thus
efficiently exchange heat with each other to further improve the
heat generating and absorbing effects of the heat storage device
15.
[0071] Moreover, a strong magnetic field required to operate the
magnetic material 16 can be easily obtained by using a cylindrical
magnet called a Halbach magnet as the magnetic field increasing and
reducing mechanism 30 and composed of the outer cylindrical magnet
302 and the inner cylindrical magnet 301, located in the hollow
portion.
THIRD EMBODIMENT
[0072] FIGS. 6A to 6D show the general structure of another example
of a refrigerator using a Stirling refrigerating cycle according to
the present invention. In FIGS. 6A to 6D, the same components as
those in FIG. 5 are denoted by the same reference numerals.
[0073] In the refrigerator shown in FIGS. 6A to 6D, a cool storage
section 32, the higher-temperature heat exchanger 17, and the
lower-temperature heat exchanger 23 are arranged inside the
cylinder main body 31. The compression piston 18 is placed in one
of the openings of the cylinder main body 31. The expansion
cylinder 24 is placed in the other opening. The magnetic field
increasing and reducing mechanism 30 is placed outside the cylinder
main body 31 along the circumference of the heat storage device 32.
The magnetic field increasing and reducing mechanism 30 is
connected to piston shaft 19 of the compression piston 18 via the
support arm 29. The magnetic field increasing and reducing
mechanism 30 can reciprocate in conjunction with the compression
piston 18.
[0074] The cool storage section 32 includes a heat storage device
321 composed of a positive magnetic material 331 which has its
temperature raised in response to an increase in the magnitude of
the magnetic field and which has its temperature lowered in
response to a decrease in the magnitude of the magnetic field, and
a storage device 322 composed of a negative magnetic material 332
which has its temperature lowered in response to an increase in the
magnitude of the magnetic field and which has its temperature
raised in response to a decrease in the magnitude of the magnetic
field. The positive magnetic material 331 is what is called a
ferromagnetic substance or a meta-magnetic substance which is in a
paramagnetic state (magnetic spins are disordered) with no magnetic
field applied to the material and which is brought to a
ferromagnetic state (magnetic spins are ordered) when a magnetic
field is applied to the material (a substance that exhibits a
order-disorder transition from the ferromagnetic state to
paramagnetic state in response to application and removal of a
magnetic field). The negative magnetic material 332 exhibits
different ordered states depending on whether or not a magnetic
field is applied and exhibits an order-order transition between the
two ordered states in response to application and removal of a
magnetic field; the degree of order is higher (the degree of
freedom of the system is lower) when no magnetic field is applied
to the segments. Specific examples of the positive magnetic
material 331 include ferromagnetic substances such as Gd and
Gd-based alloys, that is, Gd-Y, Gd-Dy, Gd-Er, and Gd-Ho alloys, and
meta-magnetic substances and ferromagnetic substances based on
La(Fe, Si) 13 or La(Fe, Al) 13. Specific examples of the negative
magnetic material 332 include substances such as a FeRH alloy which
exhibit an order-order transition from the ferromagnetic state to
an antiferromagnetic state in response to application and removal
of a magnetic field. With the FeRh alloy, the magnitude of magnetic
moment of Rh changes significantly between the two states owing to
a difference in the polarization of Rh. This changes the entropy of
an electron system.
[0075] In this refrigerator, first, as shown in FIG. 6A, the
compression piston 18 is moved in the direction A in this figure,
that is, from the left to right of the figure, to compress the
refrigerant in the cylinder main body 31 (compression cylinder 12).
At this time, actuation of the higher-temperature heat exchanger 17
radiates heat generated from the refrigerant by compression, in the
direction of arrow B in FIG. 6A to the exterior of the apparatus
via the higher-temperature heat exchanger 17. An isothermal
refrigerant compressing process is thus executed. Simultaneously
with the compression of the refrigerant, the magnetic field
increasing and reducing mechanism 30, connected to the piston shaft
19, moves, as the compression piston 18 moves, to a position where
it applies a magnetic field to the heat storage device 321. The
heat storage device 321 has its temperature raised. This is because
the heat storage device 321 is composed of the magnetic material
331 having its temperature raised (heat generation) in response to
an increase in the magnitude of a magnetic field and lowered (heat
absorption) in response to a decrease in the magnitude of the
magnetic field. At this time, the higher-temperature heat exchanger
17 is in operation. Thus, heat generated from the heat storage
device 321 can also be radiated in the direction of arrow B in FIG.
6A to the exterior of the apparatus via the higher-temperature heat
exchanger 17. On the other hands, the magnetic field from the
magnetic field increasing and reducing mechanism 30 is removed from
the cools storage device 322. The cools storage device 322 thus has
its temperature raised. This is because the heat storage device 322
is composed of the negative magnetic material 332 having its
temperature raised (heat generation) in response to removal of the
magnetic field. Since the higher-temperature heat exchanger 17 is
in operation, heat from the heat storage device 322 can also be
radiated to the exterior of the apparatus via the
higher-temperature heat exchanger 17. Thus, during the refrigerant
compressing process shown in FIG. 6A, not only heat from the
refrigerant but also heat generated from the magnetic materials 331
and 332 can be radiated to the exterior of the apparatus via the
higher-temperature heat exchanger 17. More heat can thus be
radiated.
[0076] Then, in FIG. 6B, with the volume of the cylinder main body
31 between the compression piston 18 and the expansion piston 24
remaining fixed, the compression piston 18 and expansion piston 24
are simultaneously moved rightward in FIG. 6B to move the
refrigerant rightward in the cylinder main body 31.
[0077] Then, as shown in FIG. 6C, the expansion piston 7 is moved
in the direction C in this figure, from the right to left of the
figure, to expand the refrigerant in the cylinder main body 31
(expansion cylinder 13). At this time, actuation of the
lower-temperature heat exchanger 23 allows the refrigerant cooled
by expansion to absorb external heat in the direction of arrow D in
FIG. 6C via the lower-temperature heat exchanger 23. An isothermal
refrigerant expansion process is thus executed.
[0078] Then, as shown in FIG. 6D, with the volume of the cylinder
main body 31 between the compression piston 18 and the expansion
piston 24 remaining fixed, the compression piston 18 and expansion
piston 24 are moved leftward to move the refrigerant leftward in
the cylinder main body 31. At this time, the magnetic field
increasing and reducing mechanism 30, connected to the piston shaft
19, moves 15, as the compression piston 18 moves, to a position
where it applies a magnetic field to the heat storage device 322.
This removes the magnetic field for the heat storage device 321 and
now applies it to the heat storage device 322. The heat storage
device 321 is composed of the positive magnetic material 331 that
has its temperature lowered (heat absorption) in response to a
decrease in the magnitude of the magnetic field. The temperature of
the heat storage device 321 thus lowers. However, at this time, the
lower-temperature heat exchanger 23 is in operation. Consequently,
external heat can be absorbed via the lower-temperature heat
exchanger 23. The heat storage device 322, to which the magnetic
field is applied, is composed of the negative magnetic material 332
that has its temperature lowered (heat absorption) in response to
application of a magnetic field. The temperature of the heat
storage device 322 thus lowers. However, since the
lower-temperature heat exchanger 23 is in operation, external heat
can be absorbed via the lower-temperature heat exchanger 23. In
other words, during the process shown in FIG. 6D, heat is absorbed
not only by the refrigerant but also by the magnetic materials 331
and 332. More heat can thus be absorbed.
[0079] The process shown in FIGS. 6A to 6D is repeated as described
above to repeatedly execute the four basic processes, isothermal
compression, isovolumetric cooling, isothermal expansion, and
isovolumetric heating. The Stirling refrigerating cycle is thus
implemented.
[0080] Therefore, the above embodiment can produce effects similar
to those of the second embodiment. Moreover, the cool storage
section 32 includes the heat storage device 321 composed of the
positive magnetic material 331 which has its temperature raised in
response to an increase in the magnitude of a magnetic field and
which has its temperature lowered in response to a decrease in the
magnitude of the magnetic field, and the storage device 322
composed of the negative magnetic material 332 which has its
temperature lowered in response to an increase in the magnitude of
the magnetic field and which has its temperature raised in response
to a decrease in the magnitude of the magnetic field. When heat is
radiated from the refrigerant, heat can also be radiated from the
magnetic materials 331 and 332. When the refrigerant absorbs heat,
the magnetic materials 331 and 332 can also absorb heat. This
enables more heat to be radiated and absorbed to further improve
the heat exchanging efficiency of the refrigerating cycle.
FOURTH EMBODIMENT
[0081] In the description of the above embodiments, the
refrigerator uses the Stirling refrigerating cycle having the four
basic processes, isothermal compression, isovolumetric cooling,
isothermal expansion, and isovolumetric heating. However, the
fourth embodiment shows a refrigerator to which a refrigerating
cycle of two basic processes, isothermal compression and isothermal
expansion is applied.
[0082] FIG. 7 three-dimensionally shows an embodiment of this
refrigerator.
[0083] In the figure, reference numeral 41 denotes a cylindrical
casing in which a cylindrical cylinder main body 42 is placed. The
cylinder main body 42 is open at one end and is closed at the other
end. The cylinder main body 42 is filled with a gas refrigerant,
for example, helium or nitrogen.
[0084] A heat storage device 43 is placed inside the cylinder main
body 42 closer to the closed end. The heat storage device 43 is
composed of a magnetic material 44 having its temperature changed
in response to an increase or decrease in the magnitude of a
magnetic field. In this embodiment, the magnetic material 44 is a
positive one, for example, a GD-based material, which has its
temperature raised (heat generation) in response to an increase in
the magnitude of the magnetic field, while having its temperature
lowered (heat absorption) in response to a decrease in the
magnitude of the magnetic field. As the magnetic material 44, a
porous member or a bulk material with a plurality of communication
holes for external communication is used as described in FIGS. 3A
and 3B.
[0085] A higher-temperature heat exchanger 45 and a
lower-temperature heat exchanger 46 are arranged on the respective
sides of the heat storage device 43. In this case, the
higher-temperature heat exchanger 45 is placed closer to the
opening of the cylinder main body 42. The higher-temperature heat
exchanger 45 radiates heat from a refrigerant and the heat storage
device 43. The lower-temperature heat exchanger 46 is placed closer
to the closed end of the cylinder main body 42. The
lower-temperature heat exchanger 46 absorbs external heat on the
basis of heat absorption by the refrigerant and heat storage device
43.
[0086] A piston 47 is provided in the cylinder main body 42. The
piston 47 is inserted into the cylinder main body 42 through its
opening to compress the refrigerant inside the cylinder main body
42. A piston shaft 48 is connected to the piston 42. A connecting
bar 49 is connected to the piston shaft 48 and to a flywheel 50 at
a position away from its rotating center. The connecting bar 49
thus constitutes a crank mechanism that converts a rotating motion
of the flywheel 50 into a reciprocating motion to reciprocate the
piston shaft 48 in the direction of arrow H in FIG. 48. The
flywheel 50 has its rotating center connected to a rotating shaft
52 of a driving motor 51. The flywheel 50 is rotated at a
predetermined speed.
[0087] A disk-like support plate 53 is integrally provided on the
piston shaft 47. A magnetic field increasing and reducing mechanism
55 is provided on the support plate 53 via a support arm 54. The
magnetic field increasing and reducing mechanism 55 is cylindrical
with the cylinder main body 42 located in its hollow portion. The
piston shaft 48 reciprocates in the direction of arrow H to allow
the magnetic field increasing and reducing mechanism 30 to increase
or reduce the magnitude of a magnetic field that is applied to the
heat storage device 43. Also in this case, the magnetic field
increasing and reducing mechanism 30 may be a double cylindrical
magnet called a Halbach magnet, described with reference to FIGS.
4A and 4B.
[0088] FIGS. 8A and 8B are diagrams illustrating the operation of
the refrigerator configured as described above. In FIGS. 8A and 8B,
the same components as those in FIG. 7 are denoted by the same
reference numerals.
[0089] In the refrigerator shown in FIGS. 8A and 8B, the cylinder
main body 42 is filled with a refrigerant. The heat storage device
43, higher-temperature heat exchanger 45, and lower-temperature
heat exchanger 46 are arranged inside the cylinder main body 42;
the heat storage device 43 is composed of the magnetic material 44,
which has its temperature changed in response to an increase or
decrease in the magnitude of a magnetic field. The piston 47 is
placed in the opening of the cylinder main body 42. The magnetic
field increasing and reducing mechanism 55 is placed outside the
cylinder main body 42 around the heat storage device 43. The
magnetic field increasing and reducing mechanism 55 is connected to
the piston shaft 48 of the piston 47 via the support arm 54. The
magnetic field increasing and reducing mechanism 55 can reciprocate
in conjunction with the piston 47.
[0090] In this refrigerator, first, as shown in FIG. 8A, the piston
47 is moved in direction A, that is, from the left to right in FIG.
8A, to compress the refrigerant in the cylinder main body 42. At
this time, actuation of the higher-temperature heat exchanger 45
radiates heat generated from the refrigerant by compression, in the
direction of arrow B in FIG. 8A to the exterior of the apparatus
via the higher-temperature heat exchanger 45. An isothermal
refrigerant compressing process is thus executed. Simultaneously
with the compression of the refrigerant, the magnetic field
increasing and reducing mechanism 55, connected to the piston shaft
48, moves, as the piston 47 moves, to a position where it applies a
magnetic field to the heat storage device 43. In this case, the
heat storage device 43 has its temperature raised. This is because
the heat storage device 43 is composed of the positive magnetic
material 44 having its temperature raised (heat generation) in
response to an increase in the magnitude of a magnetic field and
lowered (heat absorption) in response to a decrease in the
magnitude of the magnetic field. At this time, the
higher-temperature heat exchanger 45 is in operation. Thus, heat
generated from the heat storage device 43 can also be radiated in
the direction of arrow B in FIG. 8A to the exterior of the
apparatus via the higher-temperature heat exchanger 45. In other
words, during the refrigerant compressing process shown in FIG. 8A,
not only heat from the refrigerant but also heat generated from the
magnetic material 44 can be radiated to the exterior of the
apparatus via the higher-temperature heat exchanger 45.
[0091] Then, as shown in FIG. 8B, the piston 47 is moved in a
direction C in this figure, that is, from the right to left of the
figure, to expand the refrigerant in the cylinder main body 42. At
this time, actuation of the lower-temperature heat exchanger 46
allows the refrigerant cooled by expansion to absorb external heat
in the direction of arrow D in FIG. 8B via the lower-temperature
heat exchanger 46. An isothermal refrigerant expansion process is
thus executed. At the same time, the magnetic field increasing and
reducing mechanism 55, connected to the piston shaft 48, moves, as
the piston 47 moves, to a position where it removes the magnetic
field from the heat storage device 43. The heat storage device 43
has its temperature raised. This is because the heat storage device
43 is composed of the positive magnetic material 44 having its
temperature raised (heat generation) in response to an increase in
the magnitude of a magnetic field and lowered (heat absorption) in
response to a decrease in the magnitude of the magnetic field. At
this time, the lower-temperature heat exchanger 46 is in operation.
This enables external heat to be absorbed via the lower-temperature
heat exchanger 46. In other words, the refrigerant expansion
process shown in FIG. 8B excites not only heat absorption by the
refrigerant but also heat absorption by the magnetic material 44.
In this state, external heat can be absorbed via the
lower-temperature heat exchanger 46.
[0092] The process shown in FIGS. 8A and 8B is similarly repeated
to enable the implementation of a refrigerating cycle of two basic
processes, isothermal compression and isothermal expansion; heat is
radiated to the exterior via the higher-temperature heat exchanger
45, and external heat is absorbed via the lower-temperature heat
exchanger 46.
[0093] Therefore, also with the refrigerating cycle of two basic
processes, isothermal compression and isothermal expansion, when
the refrigerant generates heat, the magnetic material 44 is also
allowed to radiate heat. Further, when the refrigerant absorbs
heat, the magnetic material 44 is also allowed to absorb heat. This
enables a refrigerating cycle with an increased heat exchange
efficiency to be implemented. Such a refrigerating cycle can be
implemented using the cylinder main body 42 and piston 47. This
makes it possible to simplify the entire configuration of the
apparatus to reduce costs.
FIFTH EMBODIMENT
[0094] FIGS. 9A and 9B show the general configuration of another
exemplary refrigerator that uses a refrigerating cycle of two basic
processes, isothermal compression and isothermal expansion. In
FIGS. 9A and 9B, the same components as those in FIGS. 8A and 8B
are denoted by the same reference numerals.
[0095] In the refrigerator shown in FIGS. 9A and 9B, a cools
storage section 56 and the higher-temperature heat exchanger 45 and
lower-temperature heat exchanger 46 are arranged inside the
cylinder main body. The piston 47 is placed in the opening of the
cylinder main body 42. The magnetic field increasing and reducing
mechanism 55 is placed outside the cylinder main body 42 along the
periphery of the heat storage device 56. The magnetic field
increasing and reducing mechanism 55 is connected to the piston
shaft 48 of the piston 47 via the support arm 54. The magnetic
field increasing and reducing mechanism 55 can reciprocate in
conjunction with the piston 47.
[0096] The cool storage section 56 has a heat storage device 431
and a heat storage device 432 arranged in parallel; the heat
storage device 431 is composed of a positive magnetic material 441
having its temperature raised in response to an increase in the
magnitude of a magnetic field, while having its temperature lowered
in response to a decrease in the magnitude of the magnetic field,
and the heat storage device 432 is composed of a negative magnetic
material 442 having its temperature lowered in response to an
increase in the magnitude of a magnetic field, while having its
temperature raised in response to a decrease in the magnitude of
the magnetic field. The positive magnetic material 441 and negative
magnetic material 442 are similar to those described in the third
embodiment.
[0097] In this configuration, first, as shown in FIG. 9A, the
piston 47 is moved in a direction A, that is, from the left to
right in FIG. 9A, to compress the refrigerant in the cylinder main
body 42. At this time, actuation of the higher-temperature heat
exchanger 45 radiates heat generated from the refrigerant by
compression, in the direction of arrow B in FIG. 9A to the exterior
of the apparatus via the higher-temperature heat exchanger 45. An
isothermal refrigerant compressing process is thus executed.
Simultaneously with the compression of the refrigerant, the
magnetic field increasing and reducing mechanism 55, connected to
the piston shaft 48, moves, as the piston 47 moves, to a position
where it applies a magnetic field to the heat storage device 431.
In this case, the heat storage device 431 has its temperature
raised. This is because the heat storage device 431 is composed of
the positive magnetic material 441 having its temperature raised
(heat generation) in response to an increase in the magnitude of a
magnetic field and lowered (heat absorption) in response to a
decrease in the magnitude of the magnetic field. At this time, the
higher-temperature heat exchanger 45 is in operation. Thus, heat
generated from the heat storage device 431 can also be radiated in
the direction of arrow B in FIG. 8A to the exterior of the
apparatus via the higher-temperature heat exchanger 45. On the
other hand, the magnetic field from the magnetic field increasing
and reducing mechanism 55 has been removed from the heat storage
device 432. In this case, the heat storage device 432 has its
temperature raised. This is because the heat storage device 432 is
composed of the negative magnetic material 442 that has its
temperature raised (heat generation) in response to removal of the
magnetic field. Since the higher-temperature heat exchanger 45 is
in operation, heat from the heat storage device 432 can be radiated
to the exterior of the apparatus via the higher-temperature heat
exchanger 45. Thus, during the refrigerant compressing process
shown in FIG. 9A, not only heat from the refrigerant but also heat
generated from the magnetic materials 441 and 442 can be radiated
to the exterior of the apparatus via the higher-temperature heat
exchanger 17. Therefore, more heat can be radiated.
[0098] Then, as shown in FIG. 9B, the piston 47 is moved in a
direction C, that is, from the right to left in FIG. 9B, to expand
the refrigerant in the cylinder main body 42. At this time,
actuation of the lower-temperature heat exchanger 46 allows the
refrigerant cooled by expansion to absorb external heat in the
direction of arrow D in FIG. 8B via the lower-temperature heat
exchanger 46. An isothermal refrigerant expansion process is thus
executed. At the same time, the magnetic field increasing and
reducing mechanism 55, connected to the piston shaft 48, moves, as
the piston 47 moves, to a position where it applies a magnetic
field to the heat storage device 432. This removes the magnetic
field from the heat storage device 431, while a magnetic field is
applied to the heat storage device 432. The heat storage device 431
has its temperature lowered. This is because the heat storage
device 431 is composed of the positive magnetic material 441 that
has its temperature lowered (heat absorption) in response to a
decrease in the magnitude of the magnetic field. However, since the
lower-temperature heat exchanger 46 is in operation, external heat
can be absorbed via the lower-temperature heat exchanger 46. At the
same time, the heat storage device 432 has its temperature lowered.
This is because the heat storage device 432 is composed of the
negative magnetic material 442 that has its temperature lowered
(heat absorption) in response to application of a magnetic field.
However, since the lower-temperature heat exchanger 46 is in
operation, external heat can be absorbed via the lower-temperature
heat exchanger 46. During the refrigerant expanding process shown
in FIG. 9B, external heat can be absorbed via the lower-temperature
heat exchanger 46 on the basis of not only heat absorption by the
refrigerant but also heat absorption resulting from a decrease in
the temperature of the magnetic materials 441 and 442. Therefore,
more heat can be absorbed.
[0099] Similar repetition of the process shown in FIGS. 9A and 9B
enables the implementation of a refrigerating cycle of two basic
processes, isothermal compression and isothermal expansion;
external heat is absorbed via the lower-temperature heat exchanger
46, and heat is radiated to the exterior via the higher-temperature
heat exchanger 45.
[0100] This also makes it possible to exert effects similar to
those of the fourth embodiment. Further, when the refrigerant
radiates heat, the magnetic materials 441 and 442 are also allowed
to radiate heat. When the refrigerant absorbs heat, the magnetic
materials 441 and 442 are also allowed to absorb heat. This enables
more heat to be radiated and absorbed, further increasing the heat
exchange efficiency of the refrigerating cycle.
SIXTH EMBODIMENT
[0101] In the above embodiments, the magnetic field increasing and
reducing mechanism is moved to enable an increase or reduction in
the magnitude of a magnetic field for the heat storage device.
However, a sixth embodiment keeps the magnetic field increasing and
reducing mechanism stationary while enabling an increase or
reduction in the magnitude of a magnetic field for the heat storage
device.
[0102] FIG. 10 shows the general configuration of the sixth
embodiment. The same components as those in FIG. 1 are denoted by
the same reference numerals and their description is omitted.
[0103] In this case, the compression piston 6, expansion piston 7,
heat storage device 2, higher-temperature heat exchanger 4, and
lower-temperature heat exchanger 5 are arranged in the cylinder 1
filled with a refrigerant; the heat storage device 2 is composed of
the magnetic material that has its temperature changed in response
to an increase or decrease in the magnitude of a magnetic
field.
[0104] A magnetic field increasing and reducing mechanism 61 is
placed outside the cylinder 1 in association with the heat storage
device 2. As shown in FIG. 11A, the magnetic field increasing and
reducing mechanism 61 is composed of a pair of permanent magnets
62a and 62b and a pair of yokes 63a and 63b. In this case, the
permanent magnets 62a and 52b are arranged so that the cylinder 1
(heat storage device 2) is sandwiched between the magnets 62a and
62b. The yokes 63a and 63b can open and close a magnetic path
between the permanent magnets 62a and 62b. As shown in FIG. 11A,
with the magnetic path between the permanent magnets 62a and 62b
closed, the magnitude of a magnetic field for the heat storage
device is increased. As shown in FIG. 11B, with the magnetic path
between the permanent magnets 62a and 62b open, the magnitude of
the magnetic field for the heat storage device is reduced.
[0105] This refrigerator can increase or reduce the magnitude of a
magnetic field for the heat storage device by moving the yokes 63a
and 63b with the permanent magnets 62a and 62b remaining stationary
to open or close the magnetic path between the permanent magnets
62a and 62b. Consequently, effects similar to those of the first
embodiment can be produced by repeatedly increasing or reducing the
magnitude of the magnetic field in association with the isothermal
compression, isovolumetric cooling, isothermal expansion, and
isovolumetric heating processes, described in the first
embodiment.
[0106] The magnetic field increasing and reducing mechanism 61
configured as described above is also applicable to the above
second to fifth embodiments.
[0107] In the above embodiments, the magnetic material constituting
the heat storage devices in the above embodiments consists of a
uniform component with a fixed operating temperature. However, for
example, the heat storage devices may each be composed of different
components such that the operating temperature sequentially
decreases from the higher-temperature heat exchanger toward the
lower-temperature heat exchanger. Such a magnetic material makes it
possible to emphasize the different operations of the higher- and
lower-temperature heat exchangers, that is, heat generation and
heat absorption. This enables more efficient heat radiation and
absorption. Further, the higher-temperature heat exchanger and
lower-temperature heat exchangers in the above embodiments may be
composed of a magnetic material that has its temperature changed in
response to an increase or decrease in the magnitude of a magnetic
field. Moreover, the above embodiments all relate to the
refrigerator. However, the present invention is of course
applicable to a heat pump that transfers heat from a lower
temperature side to a higher temperature side.
[0108] As described above, the present invention can provide a heat
transporting apparatus which has good heat transporting capability
and which enables an increase in heat exchange efficiency.
[0109] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
* * * * *