Abstract:
A refrigeration cycle of a refrigerator includes a first refrigeration cycle in which a first refrigerant flows along a first refrigerant tube and a second refrigeration cycle in which a second refrigerant flows along a second refrigerant tube. First and second compressors compress each of the first and second refrigerants, and a combined condenser condenses each of the first and second refrigerants. First and second expansion valves phase-change each of the first and second refrigerants passing through the combined condenser, and first and second evaporators change the refrigerant passing through each of the first and second expansion valves into a low-temperature low-pressure gaseous refrigerant.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefits of priority to Korean Patent Application No. 10-2013-0133254 filed on Nov. 5, 2013, which is herein incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    The present disclosure relates to a refrigeration cycle of a refrigerator. 
         [0003]    In refrigerator according to the related art, a refrigerant is transferred from one compressor into evaporators respectively disposed at rear sides of a refrigerating compartment and freezing compartment, and then, a valve disposed in each of the evaporators is adjusted in opening degree to alternately perform an operation for cooling the freezing compartment and the refrigerating compartment. Alternatively, a freezing compartment is cooled by using a single evaporator disposed on a side of the freezing compartment, and then cool air is transferred into a refrigerating compartment by using a damper. 
         [0004]    However, in the case of the above-described structure, temperatures required for the refrigerating compartment and the freezing compartment are different from each other. Thus, to realize the temperatures required for the two storage compartments, which have a large temperature difference therebetween, in a refrigeration cycle including one compressor, the compressor may operate out of the optimum efficiency range thereof. To solve this limitation, a two-cycle refrigerator including a refrigeration cycle for a refrigerating compartment and a refrigeration cycle for a freezing compartment has been released. 
         [0005]    However, in case of the two-cycle refrigerator, following limitations occurs as ever. That is, in the two cycles, one of the limitations is that two compressors and condensers have to be installed in a machine room. As a result, the machine room may increase in volume, and thus the storage compartment may be reduced in volume. 
         [0006]    Also, if the two compressors and condensers are installed in the limited machine room, the condensers are limited in size and capacity to cause a limit in heat-dissipation area for dissipating heat. 
         [0007]    In addition, when the two condensers and two compressors are disposed in the machine room, flow resistance of indoor air that forcibly flows into the machine room by a condensation fan to deteriorate heat-dissipation efficiency of the condensers. 
         [0008]    To solve the above-described limitations of the refrigerator having the two refrigerant cycles, needs for developing a refrigerator that has a small size and high heat-dissipation efficiency due to the machine room having a limited volume are being on the rise. 
       SUMMARY 
       [0009]    The present disclosure is proposed to improve the above-described limitations. 
         [0010]    In one embodiment, a refrigeration cycle of a refrigerator including a first refrigeration cycle in which a first refrigerant flows along a first refrigerant tube and a second refrigeration cycle in which a second refrigerant flows along a second refrigerant tube includes: first and second compressors compressing each of the first and second refrigerants into a high-temperature high-pressure gaseous refrigerant; a combined condenser condensing each of the first and second refrigerants passing through the first and second compressors into a high-temperature high-pressure liquid refrigerant; first and second expansion valves phase-changing each of the first and second refrigerants passing through the combined condenser into a low-temperature low-pressure two-phase refrigerant; and first and second evaporators changing the refrigerant passing through each of the first and second expansion valves into a low-temperature low-pressure gaseous refrigerant, wherein the combined condenser includes: first and second condensation tubes constituting portions of the first and second refrigerant tubes that connect the first and second compressors to the first and second expansion valves, respectively; and heat-exchange fins contacting surfaces of the first and second condensation tubes, wherein the first and second condensation tubes share at least a portion of the heat-exchange fins, the first and second condensation tubes are bent several times to form a meander line in a state where the first and second refrigerant tubes each of which has a predetermined width and length are vertically disposed in parallel to each other, and the heat-exchange fins are inserted between the condensation tubes that are adjacent thereto. 
         [0011]    Each of the heat-exchange fins may have the same width as that of each of the first and second condensation tubes and be bent several times in a wave form, and cusps defined at the bent portions may contact one or all of surfaces of the first and second condensation tubes. 
         [0012]    The cusps may include an upper cusp and a lower cusp, and the heat-exchange fins may include: a first heat-exchange fin in which all of the upper and lower cusps contact the surface of the first condensation tube; a second heat-exchange fin in which all of the upper and lower cusps contact the surface of the second condensation tube; and a sharing heat-exchange fin in which one cusp of the upper and lower cusps contacts the surface of the first condensation tube, and the other cusp contacts the surface of the second condensation tube. 
         [0013]    In a stand-alone operation mode of the first refrigeration cycle, heat exchange may be performed through the first heat-exchange fin and the sharing heat-exchange fin, in a stand-alone operation mode of the second refrigeration cycle, the heat exchange may be performed through the second heat-exchange fin and the sharing heat-exchange fin, and in a simultaneous operation mode of the first and second refrigeration cycles, the heat exchange may be performed through all of the heat-exchange fins. 
         [0014]    The first and second condensation tubes may have the same width, and a plurality of refrigerant flow channels may be defined in the first and second condensation tubes, respectively. 
         [0015]    The refrigeration cycle may further include: an inflow-side head connected to one end of each of the first and second condensation tubes to distribute the refrigerant into the refrigerant flow channels; an inflow port disposed on one side of the inflow-side head, the inflow port being connected to the refrigerant tube that extends from each of the first and second compressors; a discharge-side head connected to the other end of each of the first and second condensation tubes to collect the refrigerant flowing along the refrigerant flow channels; and a discharge port disposed on one side of the discharge-side head, the discharge port being connected to each of the first and second expansion valves. 
         [0016]    One of the first and second evaporators may be a refrigerating compartment evaporator, and the other of the first and second evaporators may be a freezing compartment evaporator. 
         [0017]    The combined condenser and the first and second compressors may be accommodated in a machine room of the refrigerator. 
         [0018]    The first and second refrigerants may be the same kind. 
         [0019]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a system view illustrating a refrigeration cycle of a refrigerator according to an embodiment. 
           [0021]      FIG. 2  is a perspective view of a combined condenser constituting the refrigeration cycle of the refrigerator according to an embodiment. 
           [0022]      FIG. 3  is a perspective view of the combined condenser for showing heat-exchange fins participating in heat exchange when only a first refrigeration cycle is in an operation mode. 
           [0023]      FIG. 4  is a perspective view of the combined condenser for showing heat-exchange fins participating in heat exchange when only a second refrigeration cycle is in an operation mode. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0024]    Hereinafter, a refrigeration cycle of a refrigerator according to an embodiment will be described in detail with reference to the accompanying drawings. 
         [0025]      FIG. 1  is a system view illustrating a refrigeration cycle of a refrigerator according to an embodiment. 
         [0026]    Referring to  FIG. 1 , a refrigeration cycle  10  of a refrigerator according to an embodiment may include a first refrigeration cycle in which a refrigerant flowing along a first refrigerant tube  17  is heat-exchanged with cool air or external air and a second refrigeration cycle in which a refrigerant flowing along a second refrigerant tube  18  is heat-exchanged with the cool air or external air. Also, a condenser of the first refrigeration cycle and a condenser of the second refrigeration cycle share heat-exchange fins. Here, the refrigerant flowing along the first refrigerant tube  17  may be defined as a first refrigerant, and the refrigerant flowing along the second refrigerant tube  18  may be defined as a second refrigerant. The first refrigerant and the second refrigerant may be the same kind. 
         [0027]    In detail, the first refrigeration cycle may include a first compressor  11  compressing the first refrigerant into a high-temperature high-pressure gas; a second condensation part condensing the high-temperature high-pressure first refrigerant passing through the first compressor  11  into a high-temperature high-pressure liquid refrigerant; a first expansion valve  13  phase-changing the high-temperature high-pressure liquid refrigerant passing through the second condensation part into a low-temperature low-pressure two-phase refrigerant; and a first evaporator  12  absorbing heat of the refrigerant passing through the first expansion valve  13  to generate a gaseous refrigerant. 
         [0028]    Also, the second refrigeration cycle may include a second compressor  14  compressing the second refrigerant, a second condensation part condensing the second refrigerant, a second expansion valve  15  phase-changing the second refrigerant, and a second evaporator  16 . 
         [0029]    Here, the first condensation part and the second condensation part may be defined as a combined condenser  20  because the first and second condensation parts respectively include separate refrigerant tubes and share the heat-exchange fins. Also, the first compressor  11 , the second compressor  14 , and the combined condenser  20  may be disposed in a machine room of the refrigerator. A condensation fan  201  may be disposed at a point that is spaced apart from the combined condenser  20 . The condensation fan  201  may be disposed on a position at which air forcibly flowing by the condensation fan  201  passes through a gap defined between the heat-exchange fins of the combined condenser  20  and then is discharged to the outside of the machine room. 
         [0030]    Also, the first evaporator  12  may be an evaporator for cooling one of the refrigerating compartment and freezing compartment of the refrigerator. The first evaporator  12  may be disposed on a rear wall of one of the refrigerating compartment and the freezing compartment, and a first evaporation fan  121  may be disposed above or under the first evaporator  12 . Also, the second evaporator  16  may be an evaporator for cooling the other of the refrigerating compartment and freezing compartment of the refrigerator. The first evaporator  16  may be disposed on a rear wall of the other of the refrigerating compartment and the freezing compartment, and a second evaporation fan  161  may be disposed above or under the second evaporator  16 . 
         [0031]    Hereinafter, a structure of the combined condenser  20  and an operation state of the heat-exchange fins according to the operation mode will be described with reference to the accompanying drawings. 
         [0032]      FIG. 2  is a perspective view of the combined condenser constituting the refrigeration cycle of the refrigerator according to an embodiment. 
         [0033]    Referring to  FIG. 2 , the combined condenser  20  according to an embodiment has a structure in which the first and second refrigerant tubes  17  and  18  are bent several times to form a meander line in a state where the first and second refrigerant tubes  17  and  18  are vertically disposed in parallel to each other, and the heat-exchange fins are inserted between the first and second refrigerant tubes  17  and  18 . Here, the tubes corresponding to the components of the combined condenser  20 , i.e., the first and second refrigerant tubes  17  and  18  contacting the heat-exchange fins may be defined as first and second condensation tubes, respectively. 
         [0034]    In detail, a portion of the heat-exchange fins may contact the first and second refrigerant tubes  17  and  18 , and the other portion may contact only the first refrigerant tube or only the second refrigerant tube  18 . 
         [0035]    Inlet ends of the first and second refrigerant tubes  17  and  18  may be respectively connected to inflow-side heads  171  and  181 , and outlet ends may be respectively connected to discharge-side heads  172  and  182 . Also, inflow ports  173  and  182  through which the refrigerant is introduced may be disposed on one side of the inflow-side heads  171  and  181 , and discharge ports  174  and  184  through which the refrigerant is discharged may be disposed on the discharge-side heads  172  and  182 . 
         [0036]    Also, as illustrated in  FIG. 2 , each of the first and second refrigerant tubes  17  and  18  may have a plate shape with a predetermined width and length. Also, the first and second refrigerant tubes  17  and  18  may be bent several times. Also, the first and second refrigerant tubes  17  and  18  may have a multi-channel refrigerant tube structure in which a plurality of refrigerant channels are disposed in parallel to each other. 
         [0037]    Also, the heat-exchange fins may have a structure in which a thin plate having high thermal conductivity and having the same width as each of the refrigerant tubes  17  and  18  is bent or curved several times in a wave form. Also, the heat-exchange fins may be successively disposed in a longitudinal direction between the refrigerant tubes  17  and  18 . 
         [0038]    Also, cusps of the heat-exchange fins may contact only one side or both sides of the first and second refrigerant tubes  17  and  18 . Due to this structure, the air forcibly flowing by the condensation fan  201  may be heat-exchanged with the heat-exchange fins while flowing into channels formed by the bent structure of the heat-exchange fins. The channels may have a lying triangular pillar shape. 
         [0039]    The heat-exchange fins may include a first heat-exchange fin of which the cusp contacts only a surface of the first refrigerant tube  17 , a second heat-exchange fin  22  of which the cusp contacts only the second refrigerant tube  18 , and a sharing heat-exchange fin  23  of which the cusp contacts all of the first and second refrigerant tubes  17  and  18 . 
         [0040]    In detail, when viewed from one side, the lower cusp and upper cusp of the heat-exchange fins may be alternately disposed. Also, the upper and lower cusps of the first heat-exchange fin  21  may contact only the first refrigerant tube  17 . That is, a portion of the refrigerant tube extending in one direction and a portion of the refrigerant tube that is bent in a U shape at a predetermined point to extend in a reverse direction may extend parallel to each other in a state where the portions are spaced a predetermined distance from each other. Then, the first heat-exchange fin  21  may be inserted into the spaced inner space. Thus, the upper and lower cusps of the first heat-exchange fin  21  may contact the surface of the first refrigerant tube  17 . Similarly, upper and lower cusps of the second heat-exchange fin  22  may contact a surface of the second refrigerant tube  18 . 
         [0041]    The sharing heat-exchange fin  23  may be disposed on an area that faces the first and second refrigerant tubes  17  and  18 . That is, one of the upper and lower cusps of the sharing heat-exchange fin  23  may contact the surface of the first refrigerant tube  17 , and the other may contact the surface of the second refrigerant tube  18 . 
         [0042]    In the case of the combined condenser  20  having the above-described structure, the heat-exchange fins participating in the heat exchange may change according to the operation mode. That is, the heat-exchange fins participating in the heat-exchange operation are divided according to the operation mode of the refrigerator. Also, the heat-exchange operation may occur over the entire region in a width direction of the heat-exchange fins participating in the heat-exchange operation. Thus, the heat-exchange fins may be improved in availability when compared to that of the case in which the first and second condensers are simply disposed forward and backward in parallel to each other. 
         [0043]      FIG. 2  is a view of a state in which all of the first and second refrigeration cycles are in the operation mode. When all of the freezing compartment cooling operation and the refrigerating compartment cooling operation are performed, all of the heat-exchange fins may participate in the heat-exchange operation. That is, heat may be released from the refrigerant tube contacting the corresponding cusps through the cusps of the heat-exchange fins, and then be heat-exchanged with air that forcibly flows by the condensation fan  201 . 
         [0044]      FIG. 3  is a perspective view of the combined condenser for showing the heat-exchange fins participating in heat exchange when only a first refrigeration cycle is in the operation mode. 
         [0045]    Referring to  FIG. 3 , the heat-exchange fins that are expressed as solid lines may represent parts participating in the heat-exchange operation, the heat-exchange fins that are expressed as dotted lines may represent parts that do not participate in the heat-exchange operation. 
         [0046]    As illustrated in  FIG. 3 , when a first refrigeration cycle operates, a high-temperature high-pressure refrigerant flows along the first refrigerant tube  17 . Also, heat may be transferred into the first heat-exchange fin  21  contacting a surface of the first refrigerant tube  17 . Also, while the air forcibly flowing by the condensation fan  201  passes through the first heat-exchange fin  21 , the air may be heat-exchanged with the first heat-exchange fin  21 . 
         [0047]    Here, parts except for the second heat-exchange fin  22  that does not contact at all the first refrigerant tube  17 , i.e., the first heat-exchange fin  21  and the sharing heat-exchange fin  23  may absorb heat from the cusps thereof contacting the first refrigerant tube  17 . Also, the heat-exchange fins of which the cusps contact the first refrigerant tube  17  may absorb heat over the entire area in the width direction of the heat-exchange fins and then be heat-exchanged with external air. 
         [0048]      FIG. 4  is a perspective view of the combined condenser for showing the heat-exchange fins participating in heat exchange when only a second refrigeration cycle is in the operation mode. 
         [0049]    Referring to  FIG. 4 , like the case of  FIG. 3 , the heat-exchange fins that are expressed as solid lines may represent parts participating in the heat-exchange operation, the heat-exchange fins that are expressed as dotted lines may represent parts that do not participate in the heat-exchange operation. 
         [0050]    In detail, when a second refrigeration cycle operates, a high-temperature high-pressure refrigerant flows along the second refrigerant tube  18 , and the heat-exchange fins contacting the second refrigerant tube  18  participate in the heat-exchange operation. Also, unlike the first refrigeration cycle operation, all of the second heat-exchange fin  22  and the sharing heat-exchange fin  23  except for the first heat-exchange fin  21  contacting only the first refrigerant tube  17  may participate in the heat-exchange operation. 
         [0051]    According to the refrigeration cycle of the refrigerator according to the embodiment, the following effects can be obtained. 
         [0052]    First, the single-type condenser structure may be adopted for the refrigerator having the two refrigeration cycles to improve utilization efficiency of the machine room. 
         [0053]    Second, in the two-cycle structure, the two condensers may be changed in design into the single-type condenser to relatively widen the inner space of the machine room. Thus, the flow resistance of the air for the heat dissipation may be reduced in the machine room. 
         [0054]    Third, in the condenser structure according to the embodiment, since the two independent condensation refrigerant tubes share the heat-exchange fin, utilization efficiency of the heat-exchange fin may increase when compared to a case in which the two condensers are disposed in parallel to each other. 
         [0055]    That is to say, in the structure in which the two independent condensers are disposed in parallel to each other, if only one of the two cycles operates, the heat-change fin of the condenser in the refrigeration cycle that does not operate may not perform the heat-dissipation operation. 
         [0056]    However, according to the embodiment, since the two independent condensation tubes share at least one portion of the heat-exchange fins, even though only one refrigeration cycle operates, the whole heat-exchange fins contacting the condensation tube in which the refrigerant flows may perform the heat-dissipation operation. Thus, the heat-dissipation amount of the condenser may increase to improve the heat-dissipation efficiency. 
         [0057]    Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.