Hybrid Magnetic Refrigerator

Koga; Akihiro ;   et al.

Patent Application Summary

U.S. patent application number 11/689100 was filed with the patent office on 2007-10-18 for hybrid magnetic refrigerator. Invention is credited to Katsumi Hisano, Hideo Iwasaki, Akihiro Kasahara, Tadahiko Kobayashi, Akihiro Koga, Akiko Saito, Takuya Takahashi.

Application Number20070240428 11/689100
Document ID /
Family ID38603530
Filed Date2007-10-18

United States Patent Application 20070240428
Kind Code A1
Koga; Akihiro ;   et al. October 18, 2007

HYBRID MAGNETIC REFRIGERATOR

Abstract

A compact and highly efficient hybrid magnetic refrigerator includes a hybrid refrigerating apparatus wherein an evaporator of a vapor compression refrigeration cycle and a heat exchanger of a magnetic refrigeration cycle are thermally connected. The magnetic refrigeration cycle is provided with a magnetic refrigeration unit in which a magnetic substance dissipates and absorbs heat according to the increase and decrease of a magnetic field in order to heat and cool a refrigerant circulating in its vicinity. The heated refrigerant is cooled by the evaporator of the vapor compression refrigeration cycle and the cooled refrigerant is supplied to the heat exchanger cooling the outside air.


Inventors: Koga; Akihiro; (Tokyo, JP) ; Hisano; Katsumi; (Matsudo-shi, JP) ; Iwasaki; Hideo; (Kawasaki-shi, JP) ; Kasahara; Akihiro; (Sambu-gun, 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: 38603530
Appl. No.: 11/689100
Filed: March 21, 2007

Current U.S. Class: 62/3.1 ; 62/335
Current CPC Class: Y02B 30/00 20130101; Y02B 30/66 20130101; F25B 25/00 20130101; F25B 21/00 20130101; F25B 2321/0021 20130101
Class at Publication: 062/003.1 ; 062/335
International Class: F25B 21/00 20060101 F25B021/00; F25B 7/00 20060101 F25B007/00

Foreign Application Data

Date Code Application Number
Mar 30, 2006 JP 2006-095945

Claims



1. A hybrid refrigerating apparatus comprising a vapor compression refrigeration cycle device in which a first refrigerant is circulated and a magnetic refrigeration cycle device in which a second refrigerant is circulated, the vapor compression refrigeration cycle device comprising: a compressor configured to compress the first refrigerant; a condenser configured to condense the first refrigerant supplied from the compressor to dissipate heat from the first refrigerant; an expansion valve configured to expand the first refrigerant supplied from the condenser; and an evaporator configured to evaporate the first refrigerant supplied from the expansion valve to absorb heat from the second refrigerant, the first refrigerant being supplied from the evaporator to the compressor; the magnetic refrigeration cycle device comprising: a pump configured to circulate the second refrigerant; a magnetic refrigeration unit including a magnet device configured to generate a magnetic field, a magnetic substance configured to dissipate or absorb heat in accordance with the increase and decrease of the magnetic field applied from the magnetic device, and a heat exchange structure having an endothermic part in which the second refrigerant is supplied and the magnetic substance absorbs heat from the second refrigerant; a first heat exchanger configured to exchange heat between the first and second refrigerants, to which the second refrigerant is supplied, the first heat exchanger being thermally connected to the evaporator of the vapor compression refrigeration cycle, and the second refrigerant in the first heat exchanger being cooled by the evaporator; and a second heat exchanger configured to cool an atmosphere outside the second heat exchanger, the cooled second refrigerant being supplied to the second heat exchanger.

2. The hybrid refrigerating apparatus according to claim 1, wherein the heat exchange structure have an exothermic part in which the second refrigerant is supplied and the magnetic substance dissipates heat into the second refrigerant.

3. The hybrid refrigerating apparatus according to claim 1, wherein the second refrigerant is supplied to the endothermic part after absorbing heat in the evaporator.

4. The hybrid refrigerating apparatus according to claim 2, wherein the exothermic part is arranged so as to be close to the first heat exchanger

5. The hybrid refrigerating apparatus according to claim 4, wherein the exothermic part is arranged at an upstream side of the second refrigerant in respect to the first heat exchanger.

6. The hybrid refrigerating apparatus according to claim 2, wherein an heat insulating unit is provided between the exothermic part and the endothermic part.

7. The hybrid refrigerating apparatus according to claim 1, wherein the heat exchange structure includes a first pipe in which the first refrigerant flows and a second pipe in which the second refrigerant flows, and the first and second pipes are embedded in the heat exchange structure to form the evaporator and the first heat exchanger.

8. The hybrid refrigerating apparatus according to claim 7, wherein the second pipe is provided with a high-temperature side section in which the heated second refrigerant flows and a low-temperature side section in which the cooled second refrigerant flows, the high-temperature side section and the low-temperature side section are arranged in parallel, the heat exchange structure includes a tubular section which is arranged in the heat exchange structure so as to penetrate the high-temperature side section and the low-temperature side section of the second pipe for the second refrigerant to form a third heat exchanger, and the magnetic substance is arranged inside the tubular section.

9. The hybrid refrigerating apparatus according to claim 1, further comprising an actuator configured to shift the magnetic substance.

10. The hybrid refrigerating apparatus according to claim 1, wherein the compressor includes a piston configured to shift the magnetic material.

11. A hybrid refrigerating apparatus comprising the vapor compression refrigeration cycle device in which a first refrigerant is circulated and a magnetic refrigeration cycle device in which a second refrigerant is circulated, the vapor compression refrigeration cycle device comprising: a first channel in which the first refrigerant is circulated; a compressor, provided in the first channel, configured to compress a first refrigerant; an expansion valve, provided in the first channel, configured to expand the first refrigerant; a condenser configured to dissipate heat from the first refrigerant, the condenser being provided in the channel between the compressor and the expansion valve; and an evaporator configured to absorb heat from outside and transfer heat to the first refrigerant, the evaporator being provided in the channel between the expansion valve and the compressor; the magnetic refrigeration cycle device comprising: a pump configured to circulate the second refrigerant; a branch unit configured to divide the second refrigerant supplied from the pump into second and third refrigerant channels; a merging unit configured to merge the second and third refrigerant channels and return the second refrigerant through the second and third refrigerant channels to the pump; a magnetic refrigeration unit including a heat exchange structure provided with endothermic and exothermic parts, a magnet device configured to apply magnetic field to either one of the endothermic part and the exothermic part, and a magnetic substance, which is shifted between the endothermic part and the exothermic part, configured to dissipate or absorb heat in accordance with the increase and decrease of the magnetic field applied from the magnetic device, the endothermic part being arranged in the second refrigerant channel to cool the second refrigerant and the exothermic part being arranged in the third refrigerant channel to heat the second refrigerant; a first heat exchanger, configured to cool the second refrigerant, the first heat exchanger being provided in the second channel and thermally connected to the evaporator of the vapor refrigeration cycle, and the heated second refrigerant being supplied to the first heat exchanger; and a second heat exchanger configured to cool atmosphere outside the second heat exchanger, the second heat exchanger being provided in the first channel and the cooled second refrigerant being supplied to the second heat exchanger.

12. The hybrid refrigerating apparatus according to claim 11, wherein the exothermic part is arranged so as to be close to the first heat exchanger.

13. The hybrid refrigerating apparatus according to claim 11, wherein the exothermic part is arranged at an upstream side of the second refrigerant in respect to the first heat exchanger.

14. The hybrid refrigerating apparatus according to claim 11, wherein a heat insulating unit is provided between the exothermic part and the endothermic part.

15. The hybrid refrigerating apparatus according to claim 11, further comprising an actuator configured to shift the magnetic substance.

16. The hybrid refrigerating apparatus according to claim 11, wherein the compressor includes a piston configured to shift the magnetic material.
Description



CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2006-095945, filed Mar. 30, 2006, 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 compact size hybrid magnetic refrigerator.

[0004] 2. Description of the Related Art

[0005] Conventionally, a vapor compression refrigeration cycle has been generally utilized for a refrigerating apparatus for domestic, household and business use (refrigeration ability: around 0.1 to 1 kW). As is well known, this vapor compression refrigeration cycle is provided with a compressor to compress a refrigerant and an expansion valve to expand the refrigerant. A condenser to dissipate heat from the refrigerant and an evaporator to absorb heat in the refrigerant are arranged in the refrigerant channel between the compressor and the expansion valve. Accordingly, in this vapor compression refrigeration cycle, the refrigerant supplied from the compressor dissipates heat at the condenser. The refrigerant supplied from the condenser is expanded at the expansion valve and is supplied to the evaporator where heat is absorbed. The refrigerant is again supplied to the compressor and is compressed. The characteristics of this vapor compression refrigeration cycle are given as a temperature-entropy diagram (T-s diagram) and a compression-enthalpy diagram (p-h diagram), and a reversible cycle is explained in both diagrams.

[0006] In addition, for special purposes limited to very low temperature environments, JP-A 2002-106999 discloses a magnetic refrigeration cycle utilizing a magnetic substance (so-called magnetic working material), which has an exothermic and endothermic effect according to the increase and decrease of a magnetic field. This magnetic refrigeration cycle is arranged with a superconducting magnet which applies a magnetic field in the refrigerant channel path between the heat exchangers, and a magnetic working material having magneto-caloric effect is taken in and out in this magnetic field. Accordingly, in this magnetic refrigeration cycle, by the operation of applying or eliminating a magnetic field to the magnetic working material, exothermic heat and endotherm from the magnetic working material are given to the refrigerant in the refrigerant channel path. The cooled refrigerant is supplied to a radiator, and the refrigerant given heat is supplied to an exhaust heat exchanger. The magnetic working material is not limited to a material that generates heat by the application of magnetic field and absorbs heat when a magnetic field is eliminated, but is known as a material that absorbs heat when a magnetic field is applied and generates heat when a magnetic field is eliminated.

[0007] In recent years, demands for a refrigerating apparatus which is able to refrigerate down to a low temperature region (-30 degrees Celsius or lower), such as to preserve freshness of food products using quick freezing (-30 degrees Celsius or lower), is increasing for domestic, household and business use. However, conventionally, in order to realize a low temperature region (-30 degrees Celsius) for a vapor compression refrigeration cycle used generally in, such as, households, it is required to increase its compression ratio. By responding to such demand, a lubricant or coefficient of performance (COP) inside the refrigerating apparatus may deteriorate. Generally, a multistage compression and single stage expansion refrigerating cycle is employed as measures to prevent such occurrence. However, such measures are said to be unsuitable for domestic and household use due to the complexity of refrigerating system and the high-cost of such apparatus.

[0008] On the other hand, the magnetic refrigeration cycle requires an extremely large increase and decrease of the magnetic field in order to generate a large difference in temperature in a magnetic refrigeration cycle using a magnetic substance having a known magneto-caloric effect. Accordingly, quite an ambitious and sophisticated apparatus likewise a superconducting magnet is required. In a low magnetic field, which can be realized by a permanent magnet, a magnetic substance being able to generate a large temperature difference is already developed, and a magnetic refrigeration cycle using such magnetic substance has been disclosed in JP-A 2002-106999 (KOKAI).

BRIEF SUMMARY OF THE INVENTION

[0009] According to an aspect of the present invention, there is provided a hybrid refrigerating apparatus comprising a vapor compression refrigeration cycle device in which a first refrigerant is circulated and a magnetic refrigeration cycle device in which a second refrigerant is circulated,

[0010] the vapor compression refrigeration cycle device comprising:

[0011] a compressor configured to compress the first refrigerant;

[0012] a condenser configured to condense the first refrigerant supplied from the compressor to dissipate heat from the first refrigerant;

[0013] an expansion valve configured to expand the first refrigerant supplied from the condenser; and

[0014] an evaporator configured to evaporate the first refrigerant supplied from the expansion valve to absorb heat from the second refrigerant, the first refrigerant being supplied from the evaporator to the compressor;

[0015] the magnetic refrigeration cycle device comprising:

[0016] a pump configured to circulate the second refrigerant;

[0017] a magnetic refrigeration unit including a magnet device configured to generate a magnetic field, a magnetic substance configured to dissipate or absorb heat in accordance with the increase and decrease of the magnetic field applied from the magnetic device, and a heat exchange structure having an endothermic part in which the second refrigerant is supplied and the magnetic substance absorbs heat from the second refrigerant;

[0018] a first heat exchanger configured to exchange heat between the first and second refrigerants, to which the second refrigerant is supplied, the first heat exchanger being thermally connected to the evaporator of the vapor compression refrigeration cycle, and the second refrigerant in the first heat exchanger being cooled by the evaporator; and

[0019] a second heat exchanger configured to cool an atmosphere outside the second heat exchanger, the cooled second refrigerant being supplied to the second heat exchanger.

[0020] Further, according to an aspect of the present invention, there is provided a hybrid refrigerating apparatus comprising the vapor compression refrigeration cycle device in which a first refrigerant is circulated and a magnetic refrigeration cycle device in which a second refrigerant is circulated,

[0021] the vapor compression refrigeration cycle device comprising:

[0022] a first channel in which the first refrigerant is circulated;

[0023] a compressor, provided in the first channel, configured to compress a first refrigerant;

[0024] an expansion valve, provided in the first channel, configured to expand the first refrigerant;

[0025] a condenser configured to dissipate heat from the first refrigerant, the condenser being provided in the channel between the compressor and the expansion valve; and

[0026] an evaporator configured to absorb heat from outside and transfer heat to the first refrigerant, the evaporator being provided in the channel between the expansion valve and the compressor;

[0027] the magnetic refrigeration cycle device comprising:

[0028] a pump configured to circulate the second refrigerant;

[0029] a branch unit configured to divide the second refrigerant supplied from the pump into second and third refrigerant channels;

[0030] a merging unit configured to merge the second and third refrigerant channels and return the second refrigerant through the second and third refrigerant channels to the pump;

[0031] a magnetic refrigeration unit including a heat exchange structure provided with endothermic and exothermic parts, a magnet device configured to apply magnetic field to either one of the endothermic part and the exothermic part, and a magnetic substance, which is shifted between the endothermic part and the exothermic part, configured to dissipate or absorb heat in accordance with the increase and decrease of the magnetic field applied from the magnetic device, the endothermic part being arranged in the second refrigerant channel to cool the second refrigerant and the exothermic part being arranged in the third refrigerant channel to heat the second refrigerant;

[0032] a first heat exchanger, configured to cool the second refrigerant, the first heat exchanger being provided in the second channel and thermally connected to the evaporator of the vapor refrigeration cycle, and the heated second refrigerant being supplied to the first heat exchanger; and

[0033] a second heat exchanger configured to cool atmosphere outside the second heat exchanger, the second heat exchanger being provided in the first channel and the cooled second refrigerant being supplied to the second heat exchanger.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0034] FIG. 1 is a block diagram schematically showing a hybrid magnetic refrigerator according to an embodiment of the present invention.

[0035] FIG. 2 is a perspective view schematically showing a magnetic refrigeration unit shown in FIG. 1.

[0036] FIG. 3 is a block diagram schematically showing a hybrid magnetic refrigerator according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0037] There will be described a hybrid magnetic refrigerator according to an embodiment of the present invention with reference to the drawings.

[0038] FIG. 1 schematically shows the hybrid magnetic refrigerator according to a first embodiment of the present invention. The hybrid magnetic refrigerator shown in this FIG. 1 comprises a combination of a vapor compression refrigeration cycle 1 and a magnetic refrigeration cycle 10. In other words, the hybrid magnetic refrigerator shown in FIG. 1 is provided with a heat exchange connection 8, which thermally connects the vapor compression refrigeration cycle 1 and the magnetic refrigeration cycle 10. An evaporator 2 in the vapor compression refrigeration cycle 1 and a high temperature side heat exchanger 11 in the magnetic refrigeration cycle 10 are thermally attached for heat exchange at this heat exchange connection 8.

[0039] As shown in FIG. 1, the vapor compression refrigeration cycle 1 comprises a compressor 3 to compress a refrigerant and an expansion valve 5 to expand the refrigerant. A condenser 4 and the evaporator 2 within the heat exchange connection 8 are connected in the refrigerant channel between the compressor 3 and expansion valve 5. Accordingly, the refrigerant in the refrigeration cycle 1 is compressed at the compressor 3, and this compressed refrigerant is supplied to the condenser 4 where the heat from the compressed refrigerant is diffused. The compressed refrigerant is supplied from the condenser 4 to the expansion valve 5, where it is expanded and supplied to the evaporator 2. At the evaporator 2, the expanded refrigerant absorbs heat from the high temperature side heat exchanger 11 of the magnetic refrigeration cycle 10, which is thermally connected to the evaporator 2 of the vapor compression refrigeration cycle 1, so that the high temperature side heat exchanger 11 is deprived of heat quantity. Here, the evaporator 2 of the vapor compression refrigeration cycle 1 cools off the heat exchanger 11 of the magnetic refrigeration cycle 10 at approximately below 0 degrees Celsius, or preferably, in the range of 0 to -10 degrees Celsius.

[0040] The magnetic refrigeration cycle 10 is provided with a pump 14 to supply the refrigerant into the heat exchange connection 8. The refrigerant cooled down at the heat exchange connection 8 is supplied to a heat exchanger 16 where the refrigerant is heat exchanged between the external environment in which this heat exchanger 16 is situated and is circulated so that it is supplied to the pump 14 again. The heat exchange connection 8 is provided with the heat exchanger 11 and a magnetic refrigeration unit 12, which has an exothermic unit 12A and endothermic unit 12B. The heat exchanger 11 and the exothermic unit 12A of the magnetic refrigeration unit 12 are arranged at the high temperature side, and the heat exchanger 16 and the endothermic unit 12B of the magnetic refrigeration unit 12 are arranged at the low temperature side of this magnetic refrigeration cycle 10. The magnetic refrigeration unit 12 is provided with a magnet device 18 to apply magnetic field to the exothermic unit 12A and is connected to an external actuator 22 so that a magnetic substance 20 having a magneto-caloric effect is movable between the exothermic unit 12A and the endothermic unit 12B. This magnetic substance has a characteristic (magneto-caloric effect) of dissipating and absorbing heat depending on the increase and decrease of the magnetic field. The magnetic substance 20 moving between the exothermic unit 12A and the endothermic unit 12B is arranged in a tubular housing as explained later and moves therein in piston action. In the case where the magnetic substance 20 having a positive magnetic effect wherein the magnetic substance 20 dissipates heat (heat dissipation) when applied a magnetic field and absorbs heat (cools down) upon demagnetization is incorporated in the magnetic refrigeration unit 12, the magnet device 18 is arranged on the high temperature side of the magnetic refrigeration cycle 10 as shown in FIG. 1. In the case where the magnetic substance 20 possesses a negative magnetic effect, the magnet device 18 is arranged on the low temperature side of the magnetic refrigeration cycle 10. Here, as for the magnetic substance 20 having a negative magnetic effect, the magnetic substance 20 absorbs heat (cools down) when it is applied a magnetic field and dissipates heat (heat dissipation) upon demagnetization.

[0041] Meanwhile, in this magnetic refrigeration cycle 10, the magnetic refrigeration unit 12 is arranged on the high temperature side and the low temperature side of the magnetic refrigeration cycle 10, and an insulation structure is provided between the high temperature side and the low temperature side of the magnetic refrigeration unit 12 in order to prevent heat transfer between the two sides.

[0042] In the magnetic refrigeration cycle 10 shown in FIG. 1, the refrigerant supplied from the pump 3 is cooled down to the temperature of the evaporator 2 at the heat exchanger 11, which is thermally connected to the evaporator 2 of the vapor compression refrigeration cycle 1, and is supplied to the exothermic unit 12A of the magnetic refrigeration unit 12. At the exothermic unit 12A of the magnetic refrigeration unit 12, the temperature of the refrigerant is subject to increase from exothermic heat of the magnetic substance 20, however, maintains a relatively low temperature such as around 0 degrees Celsius due to being cooled in advance by the heat exchanger 11. The refrigerant maintained at a relatively low temperature is supplied to the endothermic unit 12B of the magnetic refrigeration unit 12 by the pressure from the pump 14. At this endothermic unit 12B, the magnetic substance 20 deprives the refrigerant of heat, and the refrigerant is further cooled down to, for example, -20 to -30 degrees Celsius. The sufficiently cooled refrigerant is supplied to the heat exchanger 16 on the low temperature side of the magnetic refrigeration cycle 10 and is returned again to the pump 14 via this heat exchanger 16. At the heat exchanger 16 on the low temperature side of the magnetic refrigeration cycle 10, its external environment is cooled by the supplied refrigerant.

[0043] The cooling temperature difference at each of the vapor compression refrigeration cycle 1 and the magnetic refrigeration cycle 10 shown in FIG. 1 is within the range of approximately 20 to 30 degrees Celsius, or, preferably, greater or equal to 30 degrees Celsius. Accordingly, if it can be cooled down to approximately 0 degrees Celsius at the vapor compression refrigeration cycle 1, the heat exchanger 16 of the magnetic refrigeration cycle 10 will be able to refrigerate its environmental temperature down to -30 degrees Celsius or lower.

[0044] FIG. 2 shows an example of the structure of the magnetic refrigeration unit 12 shown in FIG. 1. As shown in FIG. 1, at the connection 8, the pipe 42 where the evaporated cooling refrigerant is circulated intersects with the pipe 44 where the magnetic cooling refrigerant is circulated, thereby thermally connecting the evaporator 2 of the vapor compression refrigeration cycle 1 and the heat exchanger 11 on the high temperature side of the magnetic refrigeration cycle 10. In other words, the pipes 42 and 44 are arranged in embedded structure at the connection 8. The pipe 44 for magnetic cooling refrigerant is horseshoe-shaped. One side of this horseshoe-shaped pipe 44 for magnetic cooling refrigerant corresponds to a high temperature side pipe 44A of the magnetic refrigeration cycle 10 and the other side corresponds to a low temperature side pipe 44B of the magnetic refrigeration cycle 10. A tubular section 48 which slidably receives the magnetic substance 20 are so extended as to penetrate through the high temperature side pipe 44A and the low temperature side pipe 44B, thereby forming an embedded structure between the pipes 44A and 44B and the tubular section 48. Outside this tubular section 48 is provided an actuator 22 to selectively shift the magnetic substance 20 between the high temperature side pipe 44A and the low temperature side pipe 44B. In addition, permanent magnets 50 are arranged on both sides of the high temperature side pipe 44A where the tubular section 48 is extended, and by these permanent magnets 50, a magnetic field can be applied to the magnetic substance 20 inside the tubular section 48. Accordingly, the high temperature side and the low temperature side of the tubular section 48, which is applied a magnetic field from the permanent magnet 50, is determined as the exothermic unit 12A and the endothermic unit 12B of the magnetic refrigeration unit 12.

[0045] In the structure of the magnetic refrigeration unit 12 shown in FIG. 2, the evaporated cooling refrigerant is circulated in the pipe 42 and the magnetic cooling refrigerant is circulated in the pipe 44, and the magnetic cooling refrigerant is refrigerated by the evaporated cooling refrigerant at the connection 8. This cooled refrigerant is circulated from the high temperature side pipe 44A to the low temperature side pipe 44B. At the high temperature side pipe 44A, when the magnetic substance 20 is shifted to the exothermic section 12A of the high temperature side of the tubular section 48, the magnetic substance 20 is exothermic due to the application of magnetic field and conducts heat exchange between the magnetic cooling refrigerant. Along with the heat dissipation of the magnetic substance 20, the temperature of the magnetic cooling refrigerant increases. However, since the magnetic cooling refrigerant is cooled in advance, the magnetic cooling refrigerant maintains a relatively low temperature while being circulated in the low temperature side pipe 44B. When the magnetic substance 20 is shifted to the endothermic unit 12B of the low temperature side of the tubular section 48, the magnetic substance 20 applies an endothermic effect to the magnetic cooling refrigerant. The sufficiently cooled magnetic cooling refrigerant is supplied to the heat exchanger 16 via the low temperature side pipe 44B.

[0046] In the structure shown in FIG. 2, the connection 8 is illustrated with a pair of permanent magnets 50 arranged in two places, and a tubular section 48 is arranged between the pair of permanent magnets 50. However, it is obvious that a plurality of connections 8 may be provided, or a combination of a permanent magnet 50 and a tubular section 48 may be arranged in a plurality of places so that a plurality of endothermic units 12B are provided to the low temperature side pipe 44B to further cool the magnetic cooling refrigerant to a lower temperature. Alternatively, as is obvious from the arrangement in FIG. 2, an electromagnet may be provided instead of the permanent magnet 50. Further, it is preferable that a heat insulation zone 24 is provided between the high temperature section and low temperature side pipes 44A and 44B so that heat is not transferred to both sides.

[0047] Meanwhile, when the magnetic substance 20 has a negative magnetic effect instead of the magnetic substance 20 having the positive magnetic effect, it is obvious that the permanent magnet 50 or the electromagnet is provided on the low temperature side pipe 44B. There is no constraint on the time cycle for applying or eliminating a magnetic field to the magnetic substance 20, therefore, it may be determined appropriately in accordance with the cooling characteristics realized at the magnetic refrigeration cycle 10. Alternatively, without providing an independent actuator 22, the magnetic substance 20 may be shifted by utilizing the piston of the compressor 3 used in the vapor compression refrigeration cycle or a mechanical movement of a cylinder or some kind of mechanical movement.

[0048] In the hybrid magnetic refrigerator shown in FIGS. 1 and 2, refrigeration in a lower temperature can be realized by cooling the refrigerant of the magnetic refrigeration cycle by the vapor compression refrigeration cycle and further by the magnetic refrigeration cycle. In comparison to the case where similar refrigeration is realized by only the magnetic refrigeration cycle, because the refrigerant circulating inside the magnetic refrigeration cycle is cooled in advance, the magnetic refrigerator can be made compact.

[0049] FIG. 3 schematically shows the hybrid magnetic refrigerator according to another embodiment of the present invention. In FIG. 3, same symbols will be given and explanations will be omitted for sections and devices equivalent to those shown in FIG. 1.

[0050] In the vapor compression refrigeration cycle 1 in the hybrid magnetic refrigerator shown in FIG. 3, a receiver 6 to store a liquefied refrigerant is provided between the condenser 4 and the expansion valve 5. In other words, the refrigerant is compressed and liquefied at the compressor 3 and is temporary stored in the receiver 6 after heat is released from the liquefied refrigerant at the condenser 4. The liquefied refrigerant is supplied to the expansion valve 5 from this receiver 6 and is expanded and vaporized. The vaporized refrigerant is supplied to the evaporator 2, where it deprives heat from the periphery of the evaporator 2.

[0051] In the hybrid magnetic refrigerator shown in FIG. 3, the evaporator 2 of the vapor compression refrigeration cycle 1 and the heat exchanger 11 of the magnetic refrigeration cycle are provided in the connection 8. The heat exchanger 11 of the magnetic refrigeration cycle is cooled by the evaporator 2 of the vapor compression refrigeration cycle 1. Furthermore, the heat exchanger 11 of this magnetic refrigeration cycle is provided on the high temperature side of the magnetic refrigeration cycle.

[0052] In the magnetic refrigeration cycle 30 shown in FIG. 3, the refrigerant from the pump 32 is divided into two refrigerant channels; one on the low temperature side and the other on the high temperature side, at a branch section. Then, the refrigerant merges again at the merging section and returns to the pump 32. In the refrigerant channel on the low temperature side, the endothermic unit 12B of the magnetic refrigeration unit 12 is provided. The refrigerant is supplied via this endothermic section 12B to the heat exchanger 16, which deprives the external environment of heat, and is again returned to the pump 32. Meanwhile, in the refrigerant channel on the high temperature side, the exothermic unit 12A of the magnetic refrigeration unit 12 is provided. Heat is transferred to the refrigerant from the magnetic substance 20 at the exothermic unit 12A. The refrigerant passed through the exothermic unit 12A is supplied to the heat exchanger 11 of the magnetic refrigeration cycle, is refrigerated by the evaporator 2 of the vapor compression refrigeration cycle 1 and is returned in similar fashion to the pump 32.

[0053] The magnetic refrigeration unit 12 shown in FIG. 3 does not have the pipe 44 for magnetic cooling refrigerant formed in a horse-shoe shape in the structure shown in FIG. 2. However, it can be realized by arranging the high temperature side pipe 44A and the low temperature side pipe 44B in parallel. In other words, the refrigerant from the pump 14 is split and supplied to the high temperature side pipe 44A and low temperature side pipe 44B respectively, are again merged and returned to the pump 14. As shown in FIG. 3, likewise the magnetic refrigeration cycle shown in FIGS. 1 and 2, when the magnetic substance 20 having a positive magnetic effect is combined in the magnetic refrigeration unit 12, the magnet device 18 is arranged on the high temperature side of the magnetic refrigeration cycle. However, when the magnetic substance 20 possesses a negative magnetic effect, the magnet device 18 is arranged on the low temperature side of the magnetic refrigeration cycle 10.

[0054] In the hybrid magnetic refrigerator shown in FIG. 3, refrigeration in a lower temperature can be realized by cooling the refrigerant of the magnetic refrigeration cycle at the vapor compression refrigeration cycle and further at the magnetic refrigeration cycle. In comparison to the case where similar refrigeration is realized by only the magnetic refrigeration cycle, because the refrigerant circulating inside the magnetic refrigeration cycle is cooled in advance, the magnetic refrigerator can be made compact.

[0055] As mentioned above, according to the present invention, a hybrid magnetic refrigerator which is compact, highly efficient, can refrigerate down to a low temperature region and can be used for household, domestic and business purposes is provided.

[0056] 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.

* * * * *


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