Patent Publication Number: US-2018045434-A1

Title: Refrigeration device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2015-099398, filed on May 14, 2015 and International Patent Application No. PCT/JP2016/063837, filed on May 10, 2016, the entire content of each of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to refrigeration devices, and, more particularly, to a refrigeration device adapted to condense a refrigerant discharged from a compressor and cool a target by evaporating the refrigerant in an evaporator. 
     2. Description of the Related Art 
     Refrigeration devices provided with two independent systems of refrigerant circuits and configured to exchange heat between the evaporator of the high-temperature side refrigerant circuit and the condenser of the low-temperature side refrigerant circuit, i.e., refrigeration devices of so-called binary refrigeration system, have been known in the related art (see, for example, patent document 1). 
     Patent document 1: JP2006-170487 
     We have made rigorous study on the aforementioned refrigeration devices and found out that there is room for simplification of the related-art refrigeration devices. 
     SUMMARY OF THE INVENTION 
     In this background, a general purpose of the present invention is to provide a technology for simplifying the structure of refrigeration devices. 
     An embodiment of the present invention that addresses the above issue relates to a refrigeration device. The refrigeration device comprises: a refrigerant circuit in which a compressor, a condenser, a decompressor, and an evaporator are connected circularly in the stated order; and a regenerative refrigerator including a heat dissipation portion that compresses a working fluid enclosed in a chamber and dissipates heat produced by compression, and a heat absorption portion in which the working fluid compressed in the heat dissipation portion is expanded. A refrigerant in the condenser of the refrigeration device is cooled by heat exchange between the condenser and the heat absorption portion. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which: 
         FIG. 1  is a refrigerant circuit diagram of the refrigeration device according to the embodiment; 
         FIG. 2  is a cross sectional view schematically showing the structure of an exemplary regenerative refrigerator; 
         FIG. 3  is a front view schematically showing the appearance of the refrigeration device according to the embodiment; 
         FIG. 4A  is a front view schematically showing the appearance of the refrigeration device according to variation 1; and 
         FIG. 4B  schematically shows the neighborhood of the condenser in the refrigerant circuit of the refrigeration device according to variation 2. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will be described based on preferred embodiments with reference to the drawings. The same or equivalent constituting elements, members, and processes shown in the drawings shall be denoted by the same reference numerals, and duplicative explanations will be omitted appropriately. 
     The embodiments shall not limit the invention but serve illustrative purposes. Not all of the features and combinations thereof described in the embodiment are necessarily essential to the invention. The scales and shapes shown in the figures are defined for convenience&#39;s sake to make the explanation easy and shall not be interpreted limitatively unless otherwise specified. Terms like “first”, “second”, etc. used in the specification and claims do not indicate an order or importance by any means and are used to distinguish a certain feature from the others. 
     The refrigeration device according to the embodiment is capable of cooling the interior of a storage chamber to an extremely low temperature of about −150°. The refrigeration device according to the embodiment is configured as a combination of a regenerative refrigerator and a refrigerant circuit. In essence, the refrigeration device is configured such that the high-temperature side refrigerant circuit in a binary refrigeration device is replaced by a regenerative refrigerator.  FIG. 1  is a refrigerant circuit diagram of the refrigeration device according to the embodiment.  FIG. 2  is a cross sectional view schematically showing the structure of an exemplary regenerative refrigerator. 
     The refrigeration device  1  according to the embodiment includes a regenerative refrigerator  100 , a first thermal siphon  200 , a second thermal siphon  300 , a refrigerant circuit  400 , and storage chamber  500 . A description will now be given of the feature of each unit. 
     The regenerative refrigerator  100  is a refrigerator for cooling a condenser  404  of the refrigerant circuit  400 . The regenerative refrigerator  100  is exemplified by a Gifford-McMahon (GM) refrigerator, a pulse tube refrigerator, a Stirling refrigerator, a Solvay refrigerator, a Claude cycle refrigerator, etc. Preferably, the regenerative refrigerator  100  is a Stirling refrigerator. 
     As shown in  FIGS. 1 and 2 , the regenerative refrigerator  100  includes a chamber  110 , a movable member  120 , a regenerator  130 , and a movable member  140 . The chamber  110  is, for example, a cylinder. The chamber  110  is filled with a working fluid such as helium gas. The working fluid is hermetically stored in the chamber  110 . The movable members  120 ,  140  are configured as, for example, a piston and are capable of moving inside the chamber  110  reciprocally. The regenerator  130  is placed inside the chamber  110  between the movable member  120  and the movable member  140 . Regenerator  130  is provided with, for example, a laminated structure of metallic gauge. 
     The regenerative refrigerator  100  includes a heat dissipation portion  150  and a heat absorption portion  160  sandwiching the regenerator  130 . The heat dissipation portion  150  is, stated differently, a compression portion or a high-temperature portion. The heat absorption portion  160  is, stated differently, an expansion portion or a low-temperature portion. For example, the refrigeration cycle of the regenerative refrigerator  100  is as follows. 
     First, the working fluid is compressed as a result of the movable member  120  moving in the heat dissipation portion  150  in a direction approaching the regenerator  130  (compression stroke). The heat generated by the compression of the working fluid is dissipated via a heat dissipation fin (not shown) provided around the chamber  110 . Subsequently, the movable member  120  and the movable member  140  move, maintaining the volume therebetween. In this process, the movable member  120  moves in a direction approaching the regenerator  130 , and the movable member  140  moves in a direction away from the regenerator  130 . This causes the working fluid to pass through the regenerator  130 , maintaining a high pressure, and moves toward the side of the heat absorption portion  160  as it is cooled by the regenerator  130  (precooling stroke). 
     Subsequently, the working fluid compressed in the heat dissipation portion  150  is expanded as a result of the movable member  140  moving in the heat absorption portion  160  in a direction away from the regenerator  130  (expansion stroke). Expansion of the working fluid deprives the heat around the heat absorption portion  160 . Subsequently, the movable member  120  moves in a direction away from the regenerator  130 , and the movable member  140  moves in a direction approaching the regenerator  130 . This causes the working fluid to pass through the regenerator  130  and move toward the heat dissipation portion  150  as it cools the regenerator  130  (temperature-raising stroke). The strokes above complete one cycle. 
     The regenerative refrigerator  100  according to the embodiment has a structure in which a high-temperature side compression portion is placed at one end and a low-temperature side expansion portion is placed at the other end, sandwiching the regenerator  130 . The structure is not limited to this and other common regenerative refrigerators may be used. A Joule Thomson refrigerator may be used in place of a regenerative refrigerator. 
     The second thermal siphon  300  is a device for cooling a target of cooling by using the vaporization heat of a refrigerant and mediates heat exchange between the heat absorption portion  160  of the regenerative refrigerator  100  and the condenser  404  of the refrigerant circuit  400 . The second thermal siphon  300  includes a second condensation unit  310 , a second liquid line  320 , a second evaporation unit  340 , and a second gas line  350 . 
     The second condensation unit  310  exchanges heat with the heat absorption portion  160  of the regenerative refrigerator  100 . This causes the refrigerant in the second condensation unit  310  to be cooled and turned into a liquid. A refrigerant gas such as R508A, ethane, etc. may be used as the refrigerant. One end of the second liquid line  320  is connected to the second condensation unit  310 . The second liquid line  320  is formed of a pipe of a smaller diameter than that of the second gas line  350 . The other end of the second liquid line  320  is connected to the second evaporation unit  340 . The refrigerant turned into a liquid in the second condensation unit  310  flows into the second evaporation unit  340  via the second liquid line  320 . The second liquid line  320  is of a smaller diameter than the second gas line  350  and has a smaller flow passage area. This inhibits a reversed flow of the gas vaporized in the second evaporation unit  340  toward the second condensation unit  310 . The refrigerant in the second thermal siphon  300  is turned into a liquid in the second condensation unit  310  and is reduced in volume. Therefore, no trouble is caused in the distribution of the refrigerant even if the second liquid line  320  is configured to have a small diameter. The entirety of the second thermal siphon  300  may be formed by a pipe of the same inner diameter and the flow passage area of the second liquid line  320  may be reduced by partially extending a core through the pipe. 
     The second evaporation unit  340  is configured to be capable of exchanging heat with the condenser  404  of the refrigerant circuit  400 . In this embodiment, the second evaporation unit  340  and the condenser  404  form a cascade heat exchanger. The refrigerant flowing into the second evaporation unit  340  absorbs heat from the refrigerant flowing in the condenser  404  and evaporates. Evaporation of the refrigerant cools the refrigerant in the condenser  404 . The second evaporation unit  340  is capable of cooling the refrigerant in the condenser  404  to, for example, about −60° C.˜−40° C. 
     One end of the second gas line  350  is connected to the second evaporation unit  340 . The other end of the second gas line  350  is connected to the second condensation unit  310 . The refrigerant turned into a gas in the second evaporation unit  340  flows into the second condensation unit  310  via the second gas line  350 . The refrigerant is cooled in the second condensation unit  310  and is turned into a liquid again. 
     The refrigerant circuit  400  is provided with a compressor  402 , a condenser  404 , a capillary tube  406  as a decompressor, and an evaporator  408  as main features. These components are connected circularly in the stated order. For example, the compressor  402  is an electric compressor employing a uniphase or triphase AC power source. A refrigerant discharge pipe  410  is connected to the compressor  402 . The refrigerant discharge pipe  410  is connected to an auxiliary condenser  412 . The auxiliary condenser  412  is cooled by an air blower  414 . 
     The auxiliary condenser  412  is connected to the condenser  404 . The condenser  404  forms a cascade heat exchanger along with the second evaporation unit  340  of the second thermal siphon  300 . The refrigerant of the refrigerant circuit  400  exchanges heat with the refrigerant in the second evaporation unit  340  in the condenser  404 . This causes the condenser  404  and the heat absorption portion  160  of the regenerative refrigerator  100  to exchange heat and cools the refrigerant in the condenser  404 . The condenser  404  is connected to a vapor-liquid separator  416 . 
     A vapor phase pipe  418  and a liquid phase pipe  420  are connected to the vapor-liquid separator  416 . The vapor phase pipe  418  is a pipe to retrieve the uncondensed vapor phase refrigerant separated by the vapor-liquid separator  416 . The liquid phase pipe  420  is a pipe to retrieve the condensed liquid phase refrigerant separated by the vapor-liquid separator  416 . The vapor phase pipe  418  is connected to a second intermediate heat exchanger  424  via a first intermediate heat exchanger  422 . The liquid phase pipe  420  is connected to the first intermediate heat exchanger  422  via a capillary tube  426 . The first intermediate heat exchanger  422  has the function of cooling and condensing the vapor phase refrigerant flowing in the vapor phase pipe  418  by the evaporation of the liquid phase refrigerant decompressed in the capillary tube  426 . 
     The second intermediate heat exchanger  424  is connected to a third intermediate heat exchanger  428 . The third intermediate heat exchanger  428  is connected to the capillary tube  406  as a decompressor. The second intermediate heat exchanger  424  and the third intermediate heat exchanger  428  are heat exchangers for exchanging heat with the refrigerant directed toward the capillary tube  406  and the refrigerant returning from the evaporator  408  to the compressor  402 . 
     The capillary tube  406  is connected to the evaporator  408 . The evaporator  408  is configured to be capable of exchanging heat with the interior of the storage chamber  500 . For example, the evaporator  408  is mounted on the outer wall surface of the storage chamber  500 . The evaporator  408  is connected to a suction pipe  430 . The suction pipe  430  is connected to the suction side of the compressor  402  via the third intermediate heat exchanger  428 , the second intermediate heat exchanger  424 , and the first intermediate heat exchanger  422 . An expansion tank  434  is connected to the suction pipe  430  via the capillary tube  432  between the first intermediate heat exchanger  422  and the compressor  402 . The expansion tank  434  is a tank for storing the refrigerant when the compressor  402  ceases to operate. 
     A mixture of four types of refrigerants with different boiling points is enclosed as the refrigerant in the refrigerant circuit  400 . More specifically, a non-azeotropic mixed refrigerant containing R508A, R14, R50, and R740 are enclosed. R508A is composed of R23 (trifluoromethane: CHF 3 ) and R116 (hexafluoroethane: CF 3 CF 3 ). The composition contains R23 in an amount of 39 weight % and R116 in an amount of 61 weight %. The boiling point of R508A is −85.7° C. R14 is tetrafluoromethane (CF 4 ) and the boiling point is −127.9° C. R50 is methane (CH 4 ) and the boiling point is −161.5° C. R740 is argon (Ar) and the boiling point is −185.86° C. R5083 may be used in place of R508A. Alternatively, a singular refrigerant of R23, R116, or R117 or a mixture of two or more refrigerants may be used. 
     For example, the refrigerant is enclosed in the refrigerant circuit  400  through the following steps. First, R14 and R50 are pre-mixed and turned into an inflammable state. Then, R508A, a mixture of refrigerants R14 and R50, and R740 are pre-mixed and enclosed in the refrigerant circuit  400 . Alternatively, the refrigerants are enclosed in the descending order of boiling points. 
     A description will now be given of circulation of the refrigerant in the refrigerant circuit  400 . First, the refrigerant is compressed in the compressor  402  and is turned into a high-temperature gaseous refrigerant. The refrigerant is discharged to the refrigerant discharge pipe  410  and flows into the condenser  404  after being cooled by the auxiliary condenser  412 . The refrigerant flowing into the condenser  404  is cooled by exchanging heat with the second evaporation unit  340 . The refrigerant in the condenser  404  is cooled to about −60° C.˜−40° C. This condenses R508A in the refrigerant. The refrigerant passing through the condenser  404  flows into the vapor-liquid separator  416 . At this point of time, R14, R50, and R740 remain uncondensed and are in a gaseous state. Therefore, R508A is mainly discharged to the liquid phase pipe  420 , and R14, R50, and R740 are mainly discharged to the vapor phase pipe  418 , respectively, in the vapor-liquid separator  416 . 
     The refrigerant flowing into the liquid phase pipe  420  is decompressed by the capillary tube  426  and flows into the first intermediate heat exchanger  422 . The refrigerant flowing into the vapor phase pipe  418  is cooled in the first intermediate heat exchanger  422  by the evaporation of the refrigerant decompressed in the capillary tube  426 . The refrigerant is also cooled by exchanging heat with the refrigerant returning from the evaporator  408 . This results in an intermediate temperature of the first intermediate heat exchanger  422  of about −95° so that R14 in the vapor phase pipe  418  is condensed. R50 and R740 continue to remain in a gaseous state. The refrigerant passing through the first intermediate heat exchanger  422  flows into the second intermediate heat exchanger  424 . The intermediate temperature of the intermediate heat exchanger means the temperature of the pipe at the center of the intermediate heat exchanger. 
     The refrigerant flowing into the second intermediate heat exchanger  424  is cooled by exchanging heat with the refrigerant returning from the evaporator  408  and flows into the third intermediate heat exchanger  428 . The refrigerant flowing into the third intermediate heat exchanger  428  is cooled by exchanging heat with the refrigerant returning from the evaporator  408  and flows into the capillary tube  406 . Heat exchange in the second intermediate heat exchanger  424  and the third intermediate heat exchanger  428  cools the refrigerant and condenses R50 and R740. R50 is mainly condensed in the second intermediate heat exchanger  424  and R740 is mainly condensed in the third intermediate heat exchanger  428 . The intermediate temperature of the second intermediate heat exchanger  424  is about −110° C. and the intermediate temperature of the third intermediate heat exchanger  428  is about −140° C. 
     The refrigerant is decompressed in the capillary tube  406  and flows into the evaporator  408 . The refrigerant deprives the heat from around and evaporates in the evaporator  408 . This allows the cooling effect of the refrigerant to take place and the environment around the evaporator  408  is cooled to an extremely low temperature of about −160° C.˜−157° C. Cooling of the evaporator  408  cools interior of the storage chamber  500  to a temperature of about −150° C. Thus, an extremely low temperature can be achieved in the evaporator  408  in the final stage of the refrigerant circuit  400  by condensing the refrigerant in the vapor phase successively, using differences in boiling points of the refrigerants. 
     The refrigerant evaporated in the evaporator  408  is discharged to the suction pipe  430  and flows into the third intermediate heat exchanger  428 , the second intermediate heat exchanger  424 , and the first intermediate heat exchanger  422  successively. The refrigerator passing through the first intermediate heat exchanger  422  converges with the refrigerant evaporated in the first intermediate heat exchanger  422  and returns to the compressor  402 . 
     The compressor  402  is switched ON and OFF by a controller (not shown) based on the temperature inside the storage chamber  500 . When the controller stops the operation of the compressor  402 , the refrigerant is collected in the expansion tank  434 . When the operation of the compressor  402  is started by the controller, the refrigerant in the expansion tank  434  is returned to the compressor  402  via the capillary tube  432 . 
     The first thermal siphon  200  is a device for cooling a target of cooling by using the vaporization heat of a refrigerant and mediates heat exchange between the heat absorption portion  160  of the regenerative refrigerator  100  and the interior of the storage chamber  500 . The first thermal siphon  200  includes a first condensation unit  210 , a first liquid line  220 , a first evaporation unit  240 , and a first gas line  250 . 
     The first condensation unit  210  exchanges heat with the heat absorption portion  160  of the regenerative refrigerator  100 . This causes the refrigerant in the first condensation unit  210  to be cooled and turned into a liquid. A refrigerant gas such as R508A, ethane, etc. may be used as the refrigerant. One end of the first liquid line  220  is connected to the first condensation unit  210 . The first liquid line  220  is formed of a pipe of a smaller diameter than that of the first gas line  250 . The other end of the first liquid line  220  is connected to the first evaporation unit  240 . The refrigerant turned into a liquid in the first condensation unit  210  flows into the first evaporation unit  240  via the first liquid line  220 . The first liquid line  220  is of a smaller diameter than the first gas line  250  and has a smaller flow passage area. This inhibits a reversed flow of the gas vaporized in the first evaporation unit  240  toward the first condensation unit  210 . The refrigerant in the first thermal siphon  200  is turned into a liquid in the first condensation unit  210  and is reduced in volume. Therefore, no trouble is created in the distribution of the refrigerant even if the first liquid line  220  is configured to have a small diameter. The entirety of the first thermal siphon  200  may be formed by a pipe of the same inner diameter and the flow passage area of the first liquid line  220  may be reduced by extending a core through the pipe. 
     The first evaporation unit  240  is configured to be capable of exchanging heat with the interior of the storage chamber  500 . For example, the first evaporation unit  240  is mounted on the outer wall surface of the storage chamber  500 . The refrigerant flowing into the first evaporation unit  240  absorbs heat from the interior of the storage chamber  500  and evaporates. Evaporation of the refrigerant cools the interior of the storage chamber  500 . The first evaporation unit  240  is capable of cooling the interior of the storage chamber  500  to about −90° C.˜−80° C. 
     One end of the first gas line  250  is connected to the first evaporation unit  240 . The other end of the first gas line  250  is connected to the first condensation unit  210 . The refrigerant turned into a gas in the first evaporation unit  240  flows into the first condensation unit  210  via the first gas line  250 . The refrigerant is cooled in the first condensation unit  210  and is turned into a liquid again. 
     The interior of the storage chamber  500  is cooled to a temperature of about −150° C. while the refrigerant circuit  400  is operating normally. For this reason, the refrigerant does not evaporate in first evaporation unit  240 . Therefore, the circulation of the refrigerant in the first thermal siphon  200  is stopped. Meanwhile, when an abnormality is caused in the operation of the refrigerant circuit  400  due to, for example, a failure in the compressor  402  of the refrigerant circuit  400  and the temperature in the storage chamber  500  rises accordingly, the refrigerant starts to evaporate in the first evaporation unit  240 . This starts the circulation of the refrigerant in the first thermal siphon  200 . As a result, the temperature in the storage chamber  500  is maintained at −90° C.˜−80° C. by the first thermal siphon  200 . 
       FIG. 3  is a front view schematically showing the appearance of the refrigeration device  1  according to the embodiment. The refrigeration device  1  includes an adiabatic box  2  with an open front, a storage chamber  500 , and a machine room  600 . For example, frozen food, living tissues, specimens, etc. are stored in the storage chamber  500 . The regenerative refrigerator  100 , the compressor  402 , etc. are installed in the machine room  600 . 
     In this embodiment, the machine room  600  is located above the storage chamber  500  in the adiabatic box  2 . This allows the first condensation unit  210  thermally in contact with the heat absorption portion  160  of the regenerative refrigerator  100  to be placed vertically above the first evaporation unit  240  thermally in contact with the storage chamber  500 . This can deliver the refrigerant turned into a liquid in the first condensation unit  210  to first evaporation unit  240  easily under gravity. This also facilitates the movement of the refrigerant turned into a gas in the first evaporation unit  240  to the first condensation unit  210 . Therefore, the refrigerant can be smoothly circulated in the first thermal siphon  200 . 
     Further, the second condensation unit  310  of the second thermal siphon  300  is placed vertically above the second evaporation unit  340  in the machine room  600 . For example, the regenerative refrigerator  100  is oriented and installed such that the heat absorption portion  160  is located toward the top and the condenser  404  is placed vertically below the heat absorption portion  160 . This can deliver the refrigerant turned into a liquid in the second condensation unit  310  to the second evaporation unit  340  easily under gravity. This also facilitates the movement of the refrigerant turned into a gas in the second evaporation unit  340  to the second condensation unit  310 . Therefore, the refrigerant can be smoothly circulated in the second thermal siphon  300 . 
     As described above, the refrigeration device  1  according to the embodiment includes the refrigerant circuit  400  and the regenerative refrigerator  100 . The refrigerant in the condenser  404  is condensed by exchanging heat between the condenser  404  of the refrigerant circuit  400  and the heat absorption portion  160  of the regenerative refrigerator  100 . In essence, the refrigeration device  1  is configured such that the high-temperature side refrigerant circuit in the related-art binary refrigeration device is replaced by the regenerative refrigerator  100 . With this, the structure of the refrigeration device is simplified as compared to the related-art binary refrigeration device. 
     In the related-art binary refrigeration device, the high-temperature side refrigerant circuit cools the refrigerant in the low-temperature side refrigerant circuit to about −40°˜−35° C. By way of contrast, the regenerative refrigerator  100  is capable of cooling the refrigerant to about −60°˜−40° C. according to the embodiment. For this reason, the number of intermediate heat exchangers provided in the refrigerant circuit  400 , which corresponds to the low-temperature side refrigerant circuit of the related-art binary refrigeration device, can be reduced. The structure of the refrigeration device can be simplified also in this respect. It is also possible to simplify the composition of the refrigerant. 
     The refrigeration device  1  according to the embodiment is provided with the first thermal siphon  200 . The refrigeration device  1  is configured such that the storage chamber  500  can be cooled not only by the evaporator  408  of the refrigerant circuit  400  but also by the first evaporation unit  240  of the first thermal siphon  200 . The related-art binary refrigeration device does not function as a refrigerant circuit only with the high-temperature side refrigerant circuit or only with the low-temperature side refrigerant circuit. For this reason, the storage chamber cannot be cooled if a failure occurs in one of the refrigerant circuits. By way of contrast, the refrigeration device  1  according to the embodiment is capable of cooling the interior of the storage chamber  500  to a certain degree by the first thermal siphon  200  even if a failure occurs in the refrigerant circuit  400 . Accordingly, the reliability of the refrigeration device  1  is improved. 
     The invention is not limited to the embodiment described above and various modifications such as design changes may be made based on the knowledge of a skilled person, and the modified embodiments are also within the scope of the present invention. New embodiments created by modifying the embodiment described above will provide the combined advantages of the embodiment and the variation. 
     (Variation 1) 
       FIG. 4A  is a front view schematically showing the appearance of the refrigeration device  1  according to variation 1. The refrigeration device  1  according to variation 1 includes an adiabatic box  2 , a first storage chamber  510 , a second storage chamber  520 , and a machine room  600 . For example, the first storage chamber  510  and the second storage chamber  520  are mutually thermally insulated. The first storage chamber  510  is cooled by the evaporator  408  of the refrigerant circuit  400 . Meanwhile, the second storage chamber  520  is cooled by the first thermal siphon  200 . In essence, heat is exchanged between the first condensation unit  210  (see  FIG. 1 ) of the first thermal siphon  200  and the heat absorption portion  160  of the regenerative refrigerator  100  (see  FIG. 1 ) and the refrigerant in the first condensation unit  210  is cooled and condensed accordingly. Evaporation of the refrigerant in the first evaporation unit  240  cools the interior of the second storage chamber  520 . 
     With this configuration, two storage chambers that differ in inside temperature can be provided in the refrigeration device  1  so that the convenience of the refrigeration device  1  can be improved. Further, even if a failure occurs in the refrigerant circuit  400 , the first thermal siphon  200  can continue to cool the second storage chamber  520 . Accordingly, the reliability of the refrigeration device  1  can be improved. 
     (Variation 2) 
       FIG. 4B  schematically shows the neighborhood of the condenser  404  in the refrigerant circuit of the refrigeration device  1  according to variation 2. In the refrigeration device  1  according to variation 2, the heat absorption portion  160  of the regenerative refrigerator  100  is directly in contact with the condenser  404  of the refrigerant circuit  400 . In essence, the heat absorption portion  160  and the condenser  404  exchange heat without mediation by the second thermal siphon  300 . The configuration provides the same advantage as the embodiment. By omitting the second thermal siphon  300 , the structure of the refrigeration device  1  is further simplified.