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.
1. Field of the Invention
The present invention relates to a compact size hybrid magnetic refrigerator.
2. Description of the Related Art
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.
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.
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.
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).
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,
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.
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,
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.
There will be described a hybrid magnetic refrigerator according to an embodiment of the present invention with reference to the drawings.
As shown in
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
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.
In the magnetic refrigeration cycle 10 shown in
The cooling temperature difference at each of the vapor compression refrigeration cycle 1 and the magnetic refrigeration cycle 10 shown in
In the structure of the magnetic refrigeration unit 12 shown in
In the structure shown in
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.
In the hybrid magnetic refrigerator shown in
In the vapor compression refrigeration cycle 1 in the hybrid magnetic refrigerator shown in
In the hybrid magnetic refrigerator shown in
In the magnetic refrigeration cycle 30 shown in
The magnetic refrigeration unit 12 shown in
In the hybrid magnetic refrigerator shown in
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.
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.
Number | Date | Country | Kind |
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2006-095945 | Mar 2006 | JP | national |