Abstract:
A cooling cycle includes a first refrigerant circuit, a second refrigerant circuit and the third refrigerant circuit and switches the refrigerant circulation between the refrigerant circuits according to cooling modes so that a plurality of evaporators is efficiently controlled and Coefficient of Performance (COP) is improved by including an ejector.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2013-0154692, filed on Dec. 12, 2013 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments of the present disclosure relate to a cooling apparatus, more particularly a cooling apparatus having improved Coefficient of Performance (COP). 
         [0004]    2. Description of the Related Art 
         [0005]    A cooling apparatus having at least two cooling chambers separated by a center partition is provided so that each cooling chamber is opened/closed by a door. In addition, each cooling chamber may have an evaporator generating cooling air and a fan blowing the cooling air in to each chamber. All cooling chambers may be independently refrigerated by each evaporator and each fan, which is referred as a separate-cooling type. A representative cooling apparatus having the separate-cooling type may be a refrigerator provided with a refrigerating compartment and a freezing compartment. The freezing compartment is to store frozen food, and a proper temperature thereof may be about −18° C. Meanwhile, the refrigerating compartment is store general food, which is stored at a cool temperature without requiring freezing, and a proper temperature thereof may be about 3° C. 
         [0006]    As mentioned above, although the proper temperature of the refrigerating compartment and the proper temperature of the freezing compartment are different, evaporation temperatures of a first evaporator and a second evaporator in conventional refrigerators are the same. Because of this, a fan of the freezing compartment is rotated continuously and a fan of the refrigerating compartment is rotated intermittently as needed to blow cool air to the refrigerating compartment so that a temperature of the refrigerating compartment may be prevented from being lowered. 
         [0007]    When it is required that the refrigerating compartment be independently cooled, a load of a compressor may be increased unnecessarily since a refrigerant is compressed corresponding to the evaporation temperature required by the second evaporator. 
       SUMMARY 
       [0008]    Therefore, it is an aspect of the present disclosure to provide a cooling apparatus having an improved Coefficient of Performance (COP). 
         [0009]    Additional aspects of the present disclosure will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
         [0010]    In accordance with one aspect of the present disclosure, a cooling apparatus includes a first refrigerant circuit configured to allow a refrigerant discharged from a compressor to flow to a suction side of the compressor by passing through a condenser, an ejector, and a vapor liquid separator; a second refrigerant circuit configured to allow the refrigerant to be sucked into an inlet of the ejector to be circulated by passing through the ejector, the vapor liquid separator, a first expansion device, a first evaporator and a second evaporator; and a third refrigerant circuit configured to allow the refrigerant passing through the vapor liquid separator to be sucked into an inlet of the ejector by passing through a second expansion device and the second evaporator to bypass the first expansion device and the first evaporator, wherein the ejector may mix a refrigerant, which is discharged from the condenser in the first refrigerant circuit, and a refrigerant, which is discharged from the second evaporator in the second refrigerant circuit or the third refrigerant circuit, to discharge to the vapor liquid separator. 
         [0011]    The cooling apparatus may include a flow path switching device installed on a portion of a discharge side of the vapor liquid separator to allow a liquid refrigerant passing through the vapor liquid separator to flow through at least one of the second refrigerant circuit and the third refrigerant circuit. 
         [0012]    The cooling apparatus may include a control unit configured to control a refrigerant flow by selectively opening or closing the flow path switching device, wherein the control unit may control the flow path switching so that a refrigerant may flow in the second refrigerant circuit when power supply is started and a refrigerant may flow in the third refrigerant circuit when cooling through the second refrigerant circuit is completed. 
         [0013]    The second refrigerant circuit may be configured to allow a refrigerant passing through the first evaporator to pass through the second evaporator. 
         [0014]    The ejector may increase pressure of a refrigerant discharged from the condenser and a refrigerant discharged from the second evaporator, and discharge to the vapor liquid separator. 
         [0015]    The vapor liquid separator may separate a refrigerant discharged from the ejector into a vapor refrigerant and a liquid refrigerant, may discharge the vapor refrigerant to the first refrigerant circuit, and may discharge the liquid refrigerant to the second refrigerant circuit or the third refrigerant circuit 
         [0016]    The ejector may include a nozzle configured to decompress and expand a refrigerant discharged from the condenser, a suction unit configured to suction a refrigerant discharged from the second evaporator, a mixing unit configured to mix a refrigerant introduced to the nozzle and a refrigerant introduced to the suction unit, and a diffuser configured to raise a pressure of a refrigerant mixed in the mixing unit. 
         [0017]    The compressor may include an inverter compressor configured to control the amount of a refrigerant flow by controlling a rotation. 
         [0018]    The expansion device may include at least one of a capillary, an electronic expansion valve and a capillary tube. 
         [0019]    The cooling apparatus may further include a third expansion device provided on a discharge unit of the condenser to increase a humidity of a refrigerant introduced to the ejector. 
         [0020]    The cooling apparatus may further include a Suction Line Heat Exchanger (SLHX) configured to exchange heat between the third expansion device and the suction unit of the compressor. 
         [0021]    The first refrigerant circuit may further include a heat exchanger configured to exchange heat between the discharge unit of the condenser and the suction unit of the compressor. 
         [0022]    The second refrigerant circuit may include an intermediate expansion device provided on a discharge unit of the first evaporator to decompress a refrigerant flowing in the second evaporator. 
         [0023]    An internal diameter of the intermediate expansion device may be smaller than an internal diameter of a refrigerant pipe disposed on a suction side of the compressor. 
         [0024]    In accordance with one aspect of the present disclosure, a cooling apparatus includes a main refrigerant circuit, an entire cooling mode refrigerant circuit, a freezing mode refrigerant circuit, a flow path switching device, and an ejector. The main refrigerant circuit may include a vapor liquid separator separating a refrigerant into a vapor refrigerant and a liquid refrigerant, a compressor compressing a refrigerant by introducing the vapor refrigerant, which is separated in the vapor liquid separator and a condenser condensing a refrigerant compressed by the compressor. The entire cooling mode refrigerant circuit may be configured to pass through a first expansion device, a first evaporator, and a second evaporator. The freezing mode refrigerant circuit may be configured to pass through the second expansion device and the second evaporator to bypass the first expansion device and the first evaporator. The flow path switching device may be configured to switch a flow path to allow a liquid refrigerant introduced from the vapor liquid separator to flow through at least one of the entire cooling mode refrigerant circuit and the freezing mode refrigerant circuit. The ejector may mix a refrigerant, which is discharged from the condenser in the main refrigerant circuit, and a refrigerant, which is discharged from the second evaporator in at least one of the entire cooling mode refrigerant circuit and the freezing mode refrigerant circuit, to introduce to the vapor liquid separator 
         [0025]    The ejector may increase a pressure of a refrigerant discharged from the condenser and a refrigerant discharged from the second evaporator, and discharge to the vapor liquid separator. 
         [0026]    In accordance with one aspect of the present disclosure, a control method of a cooling apparatus provided with a first refrigerant circuit configured to allow a refrigerant discharged from a compressor to flow to a suction side of the compressor by passing through a condenser, an ejector, and a vapor liquid separator; a second refrigerant circuit configured to allow the refrigerant to be sucked into an inlet of the ejector to be circulated by passing through the ejector, the vapor liquid separator, a first expansion device, a first evaporator cooling a first cooling compartment, and a second evaporator cooling a second cooling compartment; a third refrigerant circuit configured to allow the refrigerant passing through the vapor liquid separator to be sucked into an inlet of the ejector by passing through a second expansion device and the second evaporator to bypass the first expansion device and the first evaporator, and a flow path switching device installed on a portion of a discharge side of the vapor liquid separator to switch a refrigerant flow to allow a liquid refrigerant passing through the vapor liquid separator to pass through at least one of the second refrigerant circuit and the third refrigerant circuit, includes cooling a first and a second cooling compartment by controlling the flow path switching device so that a refrigerant may flow through the first refrigerant circuit and the second refrigerant circuit; and cooling the second cooling compartment by controlling the flow path switching device so that a refrigerant may flow through the first refrigerant circuit and the third refrigerant circuit when a temperature of the first cooling compartment reaches a target temperature. 
         [0027]    The amount of a refrigerant flow in the entire cooling mode and the freezing mode may be adjusted by controlling the number of rotation of the compressor when an operation through the first refrigerant circuit and the second refrigerant circuit is referred to as an entire cooling mode, and an operation through the first refrigerant circuit and the third refrigerant circuit is referred to as a freezing mode. 
         [0028]    The first evaporator may be defrosted by supplying the compressed refrigerant discharged from the compressor to the second refrigerant circuit since the third refrigerant circuit may be closed and the second refrigerant circuit may be opened by controlling the flow path switching device when driving the compressor is stopped. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings of which: 
           [0030]      FIG. 1  is a view of a cooling apparatus according to a first embodiment of the present disclosure; 
           [0031]      FIG. 2  is a view of a refrigerant flow in an ejector in the cooling apparatus according to a first embodiment of the present disclosure; 
           [0032]      FIG. 3  is a Mollier diagram of the cooling apparatus according to a first embodiment of the present disclosure; 
           [0033]      FIG. 4  is a view of operations of each component in each mode of the cooling apparatus according to a first embodiment of the present disclosure; 
           [0034]      FIG. 5  is a view of a control diagram of the cooling apparatus according to a first embodiment of the present disclosure; 
           [0035]      FIG. 6A  is a view of a multi cycle type cooling apparatus, and  FIG. 6B  is a table comparing the multi cycle type cooling apparatus with the cooling apparatus according to a first embodiment of the present disclosure; 
           [0036]      FIG. 7  is a view of a cooling apparatus according to a second embodiment of the present disclosure; 
           [0037]      FIG. 8  is a Mollier diagram of the cooling apparatus according to a second embodiment of the present disclosure; 
           [0038]      FIG. 9  is a view of a cooling apparatus according to a third embodiment of the present disclosure; 
           [0039]      FIG. 10  is a Mollier diagram of the cooling apparatus according to a third embodiment of the present disclosure; 
           [0040]      FIG. 11  is a schematic view of a refrigerator provided with a cooling apparatus according to a fourth embodiment of the present disclosure; and 
           [0041]      FIG. 12  is a view of the cooling apparatus according to a fourth embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0042]    Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0043]      FIG. 1  is a view of a cooling apparatus according to a first embodiment of the present disclosure.  FIG. 2  is a view of the amount of refrigerant flow in an ejector in the cooling apparatus according to a first embodiment of the present disclosure. 
         [0044]    As illustrated in  FIG. 1 , a compressor  110 , a condenser  120 , a first evaporator  154 , a second evaporator  164 , and an ejector  130  may be connected by a refrigerant pipe so that a closed loop refrigerant circuit may be provided. 
         [0045]    Particularly, a cooling apparatus may include a first refrigerant circuit, a second refrigerant circuit, and a third refrigerant circuit. 
         [0046]    In the first refrigerant circuit, a refrigerant discharged from the compressor  110  may flow a suction side of the compressor  110  by passing through the condenser  120 , the ejector  130 , and a vapor liquid separator  140 . In the second refrigerant circuit, a refrigerant may flow the ejector  130 , the vapor liquid separator  140 , a first expansion device  152 , a first evaporator  154 , and a second evaporator  164  and be sucked into a suction unit  132  of the ejector  130  to be circulated. In the third refrigerant circuit, a refrigerant passed through the vapor liquid separator  140  may flow a second expansion device  162  and the second evaporator  164 , and be sucked into the suction unit  132  to bypass the first expansion device  152  and the first evaporator  154 . 
         [0047]    The first refrigerant circuit may be referred to as a main refrigerant circuit, the second refrigerant circuit may be referred to as an entire cooling mode circuit, and the third refrigerant circuit may be referred to as a freezing mode refrigerant circuit. 
         [0048]    Use of the first evaporator  154  and the second evaporator  164  are not limited thereto, but according to one embodiment of the present disclosure, the first evaporator  154  may be used for a refrigerating compartment  150  of a refrigerator, and the second evaporator  164  may be used for a freezing compartment  160  of a refrigerator. That is, the first evaporator  154  may be referred to as a refrigerating compartment evaporator and the second evaporator  164  may be referred to as a freezing compartment evaporator. 
         [0049]    A flow path switching device  170  may control a refrigerant flow between the second refrigerant circuit and the third refrigerant circuit. Particularly, the flow path switching device  170  may be installed in a discharge side of the vapor liquid separator  140  to switch a flow path so that a liquid refrigerant passed through the vapor liquid separator  140  may pass at least one of the second and the third refrigerant circuit. 
         [0050]    The flow path switching device  170  may include a three way valve. The flow path switching device  170  may include a first valve  171  opening/closing the second refrigerant circuit and a second valve  172  opening/closing the third refrigerant circuit. 
         [0051]    A condenser fan motor  122  driving a condenser fan  121 , a first fan motor  158  driving a first fan  157  of the refrigerating compartment  150 , and a second fan motor  168  driving a second fan  167  of the freezing compartment  160  may be further provided. 
         [0052]    A first defrost heater  156  and a second defrost heater  166  may be provided in the first evaporator  154  and the second evaporator  164  to remove frost on surface of the evaporators. 
         [0053]    An operating refrigerant flowing in the cooling apparatus may include HCs isobutane (R600a) and propane (R290), HFCs R134a, and HFOs R1234yf. 
         [0054]    Expansion devices  152 ,  162 ,  280 , and  390  may include a capillary, a capillary tube and an electronic expansion valve (EV). 
         [0055]    The ejector  130  may include a nozzle  131 , a suction unit  132 , a mixing unit  133 , and a diffuser  134 . A refrigerant discharged from the condenser  120  may be referred to as a main refrigerant and refrigerant discharge from the second evaporator  164  may be referred to as a sub refrigerant. The main refrigerant may flow to the mixing unit  133  through the nozzle  131 , and the sub refrigerant may be sucked into the suction unit  132 , mixed with the main refrigerant in the mixing unit  133  and then flow out from the ejector  130  through the diffuser  134 . 
         [0056]    When the main refrigerant passes through the nozzle  131 , the main refrigerant may be isentropic expansion and an enthalpy difference between the front and the back of the nozzle  131  may cause a speed difference of the main refrigerant. Therefore, the main refrigerant may be ejected at high speed from an outlet of the nozzle  131 . 
         [0057]    In the diffuser  134 , velocity energy of a mixed refrigerant in which the main refrigerant and the sub refrigerant are mixed, is converted to pressure energy, and thus there is an effect of the boost pressure. Therefore, when suctioning, compression work may be reduced so that an efficiency of a cycle may be increased. 
         [0058]    Hereinafter, a refrigerant flow in the ejector  130  will be described. 
         [0059]    The main refrigerant discharged from the condenser  120  may be introduced to an inlet of the nozzle  131  of the ejector  130 . A flow velocity of the main refrigerant may be increased and a pressure may be decreased after passing through the nozzle  131  in the ejector  130 . 
         [0060]    In an outlet of the nozzle  131 , the main refrigerant may flow in a low pressure and the sub refrigerant, which flows in a saturated gas state due to passing through the second evaporator  164  through the second refrigerant circuit or the third refrigerant circuit, may be sucked into the suction unit  132  of the ejector  130  due to a pressure difference with the main refrigerant having relative lower pressure than saturation pressure. 
         [0061]    The main refrigerant passed through the nozzle  131  and the sub refrigerant suctioned through the suction unit  132  may be mixed in the mixing unit  133  of the ejector  130 . A flow velocity of the mixed refrigerant may be reduced while passing through the diffuser  134  installed an outlet of the ejector  130  and having a fan shape, and a pressure of the mixed refrigerant may be increased and introduced to the vapor liquid separator  140 . 
         [0062]    From the vapor liquid separator  140 , a vapor refrigerant may be introduced to the suction unit of the compressor  110 , and a liquid refrigerant may pass the expansion device  152  and  162  to be a proper temperature and pressure thereof, which is required by the evaporator  154  and  164 , and be introduced to the evaporator  154  and  164 . A refrigerant in the outlet of the evaporator  154  and  164  may become a saturated gas state since a refrigerant is evaporated by absorbing heat from the ambient air while passing through the evaporator  154  and  164 . The refrigerant in the saturated gas state may be sucked into the suction unit  132  of the ejector  130 , as mentioned above, and a refrigerant circulation may be maintained. 
         [0063]    In a cycle provided with the ejector  130 , a pressure of a refrigerant sucked into the compressor  110  may be increased comparing with a cycle without the ejector  130 , thus the amount of work of the compressor  110  may be reduced when a refrigerant introduced to the compressor  110  is compressed to a condensation temperature. In addition, a liquid refrigerant passed through the vapor liquid separator  140  may flow in the evaporator  154  and  164  provided on the second refrigerant circuit or the third refrigerant circuit so that a cooling capacity may be improved and Coefficient of Performance (COP) of an entire cycle may be increased. 
         [0064]      FIG. 3  is a Mollier diagram of the cooling apparatus according to a first embodiment of the present disclosure. 
         [0065]    The compressor  110  may suction a low temperature and low pressure refrigerant from the vapor liquid separator  140  and compress low temperature and low pressure refrigerant with superheated steam having high temperature and high pressure (7→1). The superheated refrigerant with a high temperature and a high pressure by the compressor  100  may become a liquid refrigerant while passing through the condenser  120  to exchange heat with the ambient air (1→2). 
         [0066]    When a refrigerant condensed in the condenser  120  is referred to as a main refrigerant, the main refrigerant may be introduced to the nozzle  131  of the ejector  130 . While a pressure of the refrigerant introduced to the nozzle  131  is reduced, a state of the refrigerant may be changed, that is a second state, and thus the refrigerant in the outlet of the nozzle  131  may have a high speed and a low pressure (2→3). 
         [0067]    A suction flow path part having a shape of a concentric circle disposed on the same cross section with the outlet of the nozzle  131  may have a low pressure. Particularly, when a refrigerant passed through only the second evaporator  164  or both of the first evaporator  154  and the second evaporator  164  according to driving modes, is referred to as a sub refrigerant, the sub refrigerant may be introduced through the suction unit  132  of the ejector  130 . The pressure of the main refrigerant in the outlet of the nozzle  131  may be lower than that of the sub refrigerant passed through the evaporator  154  and  164  so that the sub refrigerant may be sucked through the suction unit  132  of the ejector  130 . 
         [0068]    In the mixing unit  133 , the main refrigerant passed through the nozzle and the sub refrigerant passed through the evaporator  154  and  164  may be mixed so that momentum may be transferred (3→4, 3′→4), and the mixed refrigerant may be introduced to the diffuser  134  through the mixing unit  133  (4→5). In the diffuser  134 , a flow velocity of the refrigerant may be reduced and a pressure of the refrigerant may be increased. Accordingly, while the refrigerant having increased pressure, a vapor refrigerant among the refrigerant having increased pressure may be introduced to the compressor  110  (5→7), and work of compression of the compressor  110  may be reduced as much as increased pressure by the ejector  130  thereby saving electricity. 
         [0069]    The refrigerant passed through the ejector  130  may be introduced to the vapor liquid separator  140  and may be separated into a vapor refrigerant and a liquid refrigerant. As mentioned above, the vapor refrigerant from the vapor liquid separator  140  may be introduced to the suction unit of the compressor  110  (5→7), and the liquid refrigerant may be introduced to the flow path switching device  170  (5→8). In an outlet of the flow path switching device  170 , the expansion device  152  and  162  may be provided to generate a certain temperature, which is required by the first evaporator  154  and the second evaporator  164 , and a the refrigerant may have a pressure drop while passing through the expansion device  152  and  162 . 
         [0070]    In the entire cooling mode, the first valve  171  is opened, and the second valve  172  is closed. The liquid refrigerant discharged from the vapor liquid separator  140  may have a pressure drop while passing through the first expansion device  152  (8→9). 
         [0071]    The refrigerant having a pressure drop may be circulated along the second refrigerant circuit to pass through the first evaporator  154  and the second evaporator  165  (9→10→6). The refrigerant passing through the second evaporator  164  may be sucked through the suction unit  132  of the ejector  130  and during suctioning a pressure of the refrigerant may be decreased by the main refrigerant introduced through the nozzle  131  (6→3′). 
         [0072]    In the freezing mode, the first valve  171  may be closed, and the second valve  172  may be opened. The liquid refrigerant discharged from the vapor liquid separator  140  may have a pressure drop while passing through the second expansion device  162  (8→11). 
         [0073]    The refrigerant having decreased pressure may be circulated along the third refrigerant circuit to bypass the first evaporator  154  and to pass through the second evaporator  164  (11→6′). The refrigerant passing through the second evaporator  164  may be sucked through the suction unit  132  of the ejector  130  and during suctioning a pressure of the refrigerant may be decreased by the main refrigerant introduced through the nozzle  131  (6′→3′). 
         [0074]    The flow path switching device  170  may be provided to switch a refrigerant flow between the second refrigerant circuit and the third refrigerant circuit according to temperature. 
         [0075]    Only the liquid refrigerant from the vapor liquid separator  140  may pass through the expansion device  152  and  162  to flow in the evaporator  154  and  164  so that a cooling capacity may be increased, thereby improving the efficiency of the entire cycle. 
         [0076]      FIG. 4  is a view of operations of each component in each mode of the cooling apparatus according to a first embodiment of the present disclosure. 
         [0077]    Pressure change of the refrigerant and changes in an evaporation temperature in the each evaporator according to the pressure change when the entire cooling mode and the freezing mode of a refrigerator according to an embodiment of the present disclosure are as follows. 
         [0078]    In the entire cooling mode, when the first valve  171  of the flow path switching device  170  is opened, that is the second valve  172  is closed, a refrigerant discharged from the condenser  120  may be firstly evaporated in the first evaporator  162  after firstly decompressing in the first expansion device  152 . The refrigerant firstly evaporated in the first evaporator  154  may be secondly evaporated in the second evaporator  164 . A freezing compartment  150  fan and a refrigerating compartment  150  fan may be driven at the same time. 
         [0079]    A proper temperature of a general freezing compartment may be approximately −18° C., and a proper temperature of a general refrigerating compartment may be approximately 3° C. As mentioned above, a difference between the proper temperature for the refrigerating compartment and the proper temperature for the freezing compartment may be large. Therefore, when increasing the evaporation temperature of the each evaporator to prevent the refrigerating compartment from being excessively cooling, the freezing compartment  160  may be not sufficiently cooled. In the cooling apparatus according to one embodiment of the present disclosure, when cooling in the freezing compartment  160  is not enough, the freezing compartment  160  except the refrigerating compartment  150  may be cooled according to a low evaporation temperature so that a temperature in the freezing compartment  160  may quickly reach a target temperature. 
         [0080]    When a target temperature inside the refrigerating compartment  150  is obtained, the entire cooling mode is switched to the freezing mode. 
         [0081]    In the freezing mode for cooling only the freezing compartment  160 , the second valve  172  of the flow path switching device  170  is opened, that is the first valve  171  is closed, so that the refrigerant discharged from the condenser  120  may flow to the second evaporator  164  through the second expansion device  162 . In the freezing mode, after being decompressed to have a lower pressure in the second expansion device  162 , the refrigerant may be evaporated in the second evaporator  164 . Due to the decompression of the refrigerant by the second expansion  162 , the evaporation temperature of the second evaporator  164  may be lower than that of the first evaporator  154 . At this time, only the freezing compartment  160  fan may be driven. 
         [0082]    When the entire cooling mode is switched to the freezing mode, the amount of a refrigerant flow flowing in the refrigerant circuit may be reduced. Particularly, the compressor  110  may include an inverter compressor  110  and, the amount of refrigerant flow flowing in the refrigerant circuit may be reduced by controlling the number of rotation of the compressor. 
         [0083]    When the target temperature of the freezing compartment is obtained, the compressor  110  and the second fan  167  may be stopped. After this time, the first fan  157  may be operated during a certain time t 1 , the first valve  171  may be opened, the second valve  172  may be closed, and 3° C. air inside the refrigerating compartment  150  may be circulated so that frost on the first evaporator  154  may be defrosted. Moisture generated during the defrosting may secure a high level of about 75% humidity inside the refrigerating compartment  150  to significantly contribute to keeping vegetables fresh. 
         [0084]      FIG. 5  is a view of a control diagram of the cooling apparatus according to a first embodiment of the present disclosure. 
         [0085]    A refrigerator according to one embodiment of the present disclosure may provide various cooling modes by controlling a control unit  60 , such as MICOM (Microcomputer).  FIG. 5  is a control diagram by the control unit  60  provided on the refrigerator according to one embodiment of the present disclosure. As illustrated in  FIG. 5 , a key input unit  52 , a refrigerating compartment temperature detecting unit  54 , a freezing compartment temperature detecting unit  56 , and a first evaporator temperature detecting unit  58  may be connected to an input port of the control unit  60 . On the key input unit  52 , various function keys may be provided and the various function keys may be related to setting driving conditions of the refrigerator, such as setting refrigerating modes and setting target temperatures. The refrigerating compartment temperature detecting unit  54  and the freezing compartment temperature detecting unit  56  may detect temperatures inside the refrigerating compartment  150  and the freezing compartment  160 , respectively to provide the temperatures to the control unit  60 . The first evaporator temperature detecting unit  58  may detect an evaporation temperature of the refrigerant in the first evaporator  154  to provide to the control unit  60 . 
         [0086]    A compressor driving unit  62 , a first fan driving unit  64 , a second fan driving unit  66 , a flow path switching device driving unit  68 , a display unit  70 , and a defrost heater driving unit  72  may be connected to an output port of the control unit  60 . The driving units except for the display unit  70  may drive the compressor  110 , the refrigerating compartment fan motor  158 , the freezing compartment fan motor  168 , the first valve  171  and the second valve  172  of the flow path switching device  170 , and the defrost heater  156  and  166 , respectively. The display unit  70  may display an operation state of the cooling apparatus, various setting values, temperatures, etc. 
         [0087]    The control unit  60  may control the flow path switching device  170  to allow a refrigerant to be circulated on at least one of the second refrigerant circuit and the third refrigerant circuit, as illustrated in  FIG. 5 , so that various cooling modes may be realized. A representative cooling mode in the refrigerator according to one embodiment of the present disclosure may be a first cooling mode, that is an entire cooling mode, and a second cooling mode, that is a freezing mode. The entire cooling mode may be defined as an operation mode cooling both the refrigerating compartment  150  and the freezing compartment  160 . The control unit  60  may open the first valve  171  of the flow path switching device  170  to realize the entire cooling mode. In the entire cooling mode, a refrigerant discharge from the condenser  120  may be circulated through the first expansion device  152 , the first evaporator  154  and the second evaporator  164 . 
         [0088]    The freezing mode may be defined as an operation mode cooling only the freezing compartment  160 . The control unit  60  may open the second valve  172  of the flow path switching device  170  to realize the freezing mode. In the freezing mode, a refrigerant discharge from the condenser  120  may be circulated through the second expansion device  162 , and the second evaporator  164 . 
         [0089]    By this configuration, as mentioned above, when cooling the refrigerating compartment  150  and the freezing compartment  160  through the first evaporator  154  and the second evaporator  164 , respectively, the refrigerator may be initially operated in a simultaneous cooling mode, and when reaching a predetermined temperature, the simultaneous cooling mode may be switched to a cooling mode cooling only the freezing compartment  160 , thereby maximizing cooling capacity. In addition, the refrigerant having increased pressure by the ejector  130  may be sucked into the compressor  110  so that work of compression may be reduced. The entire cooling mode may allow a refrigerant passed through the first evaporator  154  to pass through the second evaporator  164 , so that a liquid refrigerant, which is not evaporated in the first evaporator  154 , may be evaporated in the second evaporator  164 , and thus a refrigerant sufficiently evaporated may be sucked into the suction unit  132  of the ejector  130 . Therefore, the suction operation of the ejector  130  may be smooth, and thereby a stable operation may be obtained. Further, the amount of refrigerant flow using in the entire cooling mode may be less than the amount of refrigerant flow using in the freezing mode, and a difference may be controlled by the number of a rotation of the inverter compressor  110  so that efficient operation may be obtained. 
         [0090]      FIG. 6A  is a view of a multi cycle type cooling apparatus, and  FIG. 6B  is a table comparing the multi cycle type cooling apparatus with the cooling apparatus according to a first embodiment of the present disclosure. 
         [0091]      FIG. 6A  is a view illustrating a multi cycle type cooling apparatus (A) not having the ejector  130  and the vapor liquid separator  140 , and  FIG. 6B  is a table of comparing coefficient of performance of the multi cycle type cooling apparatus (A) with the cooling apparatus (B) according to one embodiment of the present disclosure. 
         [0092]    The multi cycle type cooling apparatus (A) may include a first refrigerant circuit and a second refrigerant circuit and a flow path switching device  170   a . In the first refrigerant circuit, a refrigerant discharged from a compressor  110   a  may flow to a suction side of the compressor  110   a  through a condenser  120   a , a first expansion device  152   a , a first evaporator  154   a  and a second evaporator  164   a . In the second circuit, a refrigerant passed through the condenser  120   a  may flow to a suction side of the compressor  110   a  through a second expansion device  162   a  and a second evaporator  164   a , and then bypass the first evaporator  154   a  and the first expansion device  152   a . The flow path switching device  170   a  may switch a flow path so that the refrigerant may flow through at least one of the first refrigerant circuit and the second refrigerant circuit. 
         [0093]    In  FIG. 6B , QR represents a freezing capacity in the refrigerating compartment  150 , QF represents a freezing capacity in the freezing compartment  160 , m represents a flow, Q 1  represents a freezing capacity in the entire cooling mode, W 1  represents the amount of work of the compressor  110  in the entire cooling mode, Q 2  represents freezing capacity in the freezing mode, and W 2  represents the amount of work of the compressor  110  in the entire cooling mode. 
         [0094]    Coefficient of Performance (COP) may be a value obtained by dividing a total freezing capacity (Qt) of the combined Q 1  and Q 2  with the total amount of work (Wt) of the compressor of the combined W 1  and W 2 . To compare COP of the multi cycle type cooling apparatus (A) with COP of the cooling apparatus (B) according to one embodiment of the present disclosure, when COP of the multi cycle type cooling apparatus (A) is assumed as 1, COP — 1 may represent COP of the cooling apparatus (B) according to one embodiment of the present disclosure. 
         [0095]    As illustrated in the table shown in  FIG. 6B , each cooling capacity in the entire cooling mode and the freezing mode may set to be the same value to compare the performance of the cycle. 
         [0096]    In comparison with the multi cycle type cooling apparatus (A), the cooling apparatus (B) may have a larger the amount of refrigerant flow since a vapor refrigerant and a liquid refrigerant may be independently circulated using by the vapor liquid separator  140 . In addition, in comparison with the entire cooling mode, in the freezing mode, the first evaporator  154  may be bypassed so that the amount of refrigerant flow may be less. 
         [0097]    Accordingly, in comparison with the multi cycle type cooling apparatus (A), COP of the cooling apparatus (B) according to one embodiment may be improved by 1.2 times. That is, the vapor liquid separator  140  may allow the liquid refrigerant to sufficiently flow in the evaporator so that a cooling capacity may be improved and in comparison with the multi cycle type cooling apparatus (A) being not provided with the ejector  130 , the cooling apparatus may provided with the ejector  130  to increase pressure of suctioned refrigerant to the compressor  110  so that the amount of work of compression of the compressor  110  may be reduced. 
         [0098]      FIG. 7  is a view of a cooling apparatus according to a second embodiment of the present disclosure, and  FIG. 8  is a Mollier diagram of the cooling apparatus according to a second embodiment of the present disclosure. 
         [0099]    Hereinafter, a cooling apparatus according to a second embodiment of the present disclosure will be described. 
         [0100]    A description of the same parts as those described above will be omitted. For example, the diffuser  134  shown in the first embodiment is shown as the diffuser  234  in the second embodiment. 
         [0101]    Particularly, a cooling apparatus may include a first refrigerant circuit, a second refrigerant circuit, and a third refrigerant circuit. 
         [0102]    In the first refrigerant circuit, a refrigerant discharged from a compressor  210  may flow to a suction side of the compressor  210  through a condenser  220 , an ejector  230 , and a vapor liquid separator  240 . In the second refrigerant circuit, a refrigerant may be sucked into an inlet of the ejector  230  to be circulated by passing through the ejector  230 , the vapor liquid separator  240 , a first expansion device  252 , a first evaporator  254  and a second evaporator  264 . In the third refrigerant circuit, the refrigerant passing through the vapor liquid separator  240  may be sucked into an inlet of the ejector  230  by passing through a second expansion device  262  and the second evaporator  264  to bypass the first expansion device  252  and the first evaporator  254 . 
         [0103]    Use of the first evaporator  254  and the second evaporator  264  are not limited thereto, but according to one embodiment of the present disclosure, the first evaporator  254  may be used in a refrigerating compartment  250  of a refrigerator, and the second evaporator  264  may be used in a freezing compartment  260  of a refrigerator. That is, the first evaporator  254  may be referred to as a refrigerating compartment evaporator and the second evaporator  264  may be referred to as a freezing compartment evaporator. 
         [0104]    A flow path switching device  270  may control the amount of refrigerant flow between the second refrigerant circuit and the third refrigerant circuit. Particularly, the flow path switching device  270  may be installed in a discharge side of the vapor liquid separator  240  to switch a flow path so that a liquid refrigerant passed through the vapor liquid separator  240  may pass at least one of the second and the third refrigerant circuit. 
         [0105]    The flow path switching device  270  may include a three way valve. The flow path switching device  270  may include a first valve  271  opening/closing the second refrigerant circuit and a second valve  272  opening/closing the third refrigerant circuit. 
         [0106]    A condenser fan motor  222  driving a condenser fan  221 , a first fan motor  258  driving a first fan  257  of the refrigerating compartment  250 , and a second fan motor  268  driving a second fan  267  of the freezing compartment  260  may be further provided. 
         [0107]    A first defrost heater  256  and a second defrost heater  266  may be provided in the first evaporator  254  and the second evaporator  264  to remove frost on surface of the evaporators. 
         [0108]    The first refrigerant circuit may include heat exchangers  270  and  272 . 
         [0109]    The heat exchanger  270  and  272  may be provided to exchange heat between a discharge unit of the condenser  220  and an inlet of the compressor  210 . It is desirable that a liquid refrigerant may be introduced to the compressor  210 , but a vapor refrigerant may be introduced. Thus, for the prevention of damage or the performance degradation of the compressor  210 , the heat exchangers  270  and  272  may be provided to exchange heat between an outlet of the condenser  220  and the inlet of the compressor  210 . 
         [0110]    The heat exchangers  270  and  272  may include a first heat exchanger  270  provided on the discharge unit of the condenser  220  and a second heat exchanger  272  provided on the inlet of the compressor  210 . By transferring heat from the first heat exchanger  270  to the second heat exchanger  272  ( 2 ″ in  FIG. 2 ), a liquid refrigerant may be overheated to be a vapor refrigerant. ( 7 ″ in  FIG. 8 ) 
         [0111]    The first refrigerant circuit may include a third expansion device  280 . 
         [0112]    The third expansion device  280  may be installed between the condenser  220  and the ejector  230 . When a refrigerant introduced to a nozzle  231  of the ejector  230  is in a two phase state, an efficiency of the ejector  230  may be improved. Therefore, the third expansion device  280  may be provided so that a humidity of a refrigerant discharged from the condenser  220  may be increased. 
         [0113]    The third expansion device  280  the heat exchangers  270  and  272  may be provided at the same time. The heat exchangers  270  and  272  may include a Suction Line heat exchanger (SLHX) provided between the third expansion device  280  and the suction unit of the compressor  210 . Superheat of a refrigerant introduced to the compressor  210  may be obtained by the Suction Line heat exchanger (SLHX) so that a damage to the compressor  210  caused by introducing a liquid refrigerant may be prevented and an efficiency of the ejector may be improved by the third expansion device  230 . 
         [0114]    It may be desirable that the amount of pressure drop by the third expansion device  280  is within 30% of the amount of pressure drop by the nozzle  231  of the ejector  230 . 
         [0115]      FIG. 9  is a view of a cooling apparatus according to a third embodiment of the present disclosure, and  FIG. 10  is a Mollier diagram of the cooling apparatus according to a third embodiment of the present disclosure. 
         [0116]    Hereinafter, a cooling apparatus according to a third embodiment of the present disclosure will be described. 
         [0117]    A description of the same parts as those described above will be omitted. For example, the diffuser  134  shown in the first embodiment is shown as the diffuser  334  in the third embodiment. 
         [0118]    Particularly, a cooling apparatus may include a first refrigerant circuit, a second refrigerant circuit, and a third refrigerant circuit. 
         [0119]    In the first refrigerant circuit, a refrigerant discharged from a compressor  310  may flow to a suction side of the compressor  310  through a condenser  320 , an ejector  330 , and a vapor liquid separator  340 . In the second refrigerant circuit, a refrigerant may be sucked into an inlet of the ejector  330  to be circulated by passing through the ejector  330 , the vapor liquid separator  340 , a first expansion device  352 , a first evaporator  354  and a second evaporator  364 . In the third refrigerant circuit, the refrigerant passing through the vapor liquid separator  340  may be sucked into an inlet of the ejector  330  by passing through a second expansion device  362  and the second evaporator  364  to bypass the first expansion device  352  and the first evaporator  354 . 
         [0120]    Use of the first evaporator  354  and the second evaporator  364  are not limited thereto, but according to one embodiment of the present disclosure, the first evaporator  354  may be used in a refrigerating compartment  350  of a refrigerator, and the second evaporator  364  may be used in a freezing compartment  360  of a refrigerator. That is, the first evaporator  354  may be referred to as a refrigerating compartment evaporator and the second evaporator  364  may be referred to as a freezing compartment evaporator. 
         [0121]    A flow path switching device  370  may control the amount of refrigerant flow between the second refrigerant circuit and the third refrigerant circuit. Particularly, the flow path switching device  370  may be installed in a discharge side of the vapor liquid separator  340  to switch a flow path so that liquid refrigerant passed through the vapor liquid separator  340  may pass at least one of the second and the third refrigerant circuit. 
         [0122]    The flow path switching device  370  may include a three way valve. The flow path switching device  370  may include a first valve  371  opening/closing the second refrigerant circuit and a second valve  372  opening/closing the third refrigerant circuit. 
         [0123]    A condenser fan motor  322  driving a condenser fan  321 , a first fan motor  358  driving a first fan  357  of the refrigerating compartment  350 , and a second fan motor  368  driving a second fan  367  of the freezing compartment  360  may be further provided. 
         [0124]    A first defrost heater  356  and a second defrost heater  366  may be provided in the first evaporator  354  and the second evaporator  364  to remove frost on surface of the evaporators. 
         [0125]    When two evaporators connected by a refrigerant pipe having the same internal diameter as a refrigerant pipe provided in a suction side of the compressor  310 , in the entire cooling mode, each evaporation temperature of the first evaporator  354  and the second evaporator  364  may be the same. In this case, when considering cooling the freezing compartment  360  and decreasing the evaporation temperature of the second evaporator  364 , a surface of the first evaporator  354  may be frosted up, and when increasing the evaporation temperature of the second evaporator  364  to prevent frost, sufficient cooling of the freezing compartment  360  may not be obtained. 
         [0126]    Those difficulties may be solved by connecting the second evaporator  364  and the first evaporator  354  to an intermediate expansion device  390 . 
         [0127]    The first expansion device  352  may decrease a pressure of a refrigerant passing through the condenser  320  so that a refrigerant may be evaporated at an evaporation temperature required by the first evaporator  354 . The intermediate expansion device  390  may decrease a pressure of the refrigerant passing through the first evaporator  354  once again so that the refrigerant may be evaporated at an evaporation temperature required by the second evaporator  364 . ( 12  in  FIG. 10 ) That is because the evaporation temperature required by the second evaporator  364  may be lower than the evaporation temperature required by the first evaporator  354 . The second expansion device  362  may decompress the refrigerant passing through the condenser  320  so that the refrigerant may be evaporated at an evaporation temperature required by the second evaporator  364 . That is the second expansion device  362  may directly decompress the refrigerant passing through the condenser  320  until the refrigerant may be evaporated at the evaporation temperature required by the second evaporator  364 , whereas the intermediate expansion device  390  may decrease a pressure of the refrigerant, which is firstly decompressed by the first expansion device  352 , once again. In this regard, a resistance of the second expansion device  362  may be larger than that of the intermediate expansion device  390  and accordingly a level of the decompression in the second expansion device  362  and the intermediate expansion device  390  may allow the evaporation temperature required by the second evaporator  364  to be realized. In addition, an internal diameter of the intermediate expansion device  390  may be smaller than that of the refrigerant pipe disposed on the suction side of the compressor  310 , e.g. approximately 2˜4 mm, so that the refrigerant may be compressed while passing through the intermediate expansion device  390 . When the internal diameter of the intermediate expansion device  390  may be extremely large, an evaporation temperature difference between two evaporators may be not significant, and when the internal diameter of the intermediate expansion device  390  is extremely small, an excessively large resistance may be generated in a refrigerant flow in which a liquid refrigerant and a vapor refrigerant are mixed in the first evaporator  354  and thereby a cooling speed of the refrigerating compartment  350  may be slow. 
         [0128]      FIG. 11  is a schematic view of a refrigerator provided with a cooling apparatus according to a fourth embodiment of the present disclosure and  FIG. 12  is a view of the cooling apparatus according to a fourth embodiment of the present disclosure. 
         [0129]    Hereinafter, a cooling apparatus according to a fourth embodiment of the present disclosure will be described. 
         [0130]    A description of the same parts as those described above will be omitted. For example, the diffuser  134  shown in the first embodiment is shown as the diffuser  434  in the fourth embodiment. 
         [0131]    A refrigerator may include a refrigerating compartment  401 , a freezing compartment  402 , and a converting compartment  403 . Those sections may be configured to have three independent temperature zones. 
         [0132]    The refrigerator may be driven by a dual loop cycle. The dual loop cycle may include a first cooling apparatus  404  and a second cooling apparatus  400 . 
         [0133]    The first cooling apparatus  404  and the second cooling apparatus  400  may be independently operated without interfering with each other. 
         [0134]    The first cooling apparatus  404  may be provided to lower a temperature inside the refrigerating compartment  401  to a target temperature. 
         [0135]    The first cooling apparatus  404  may include a compressor  405 , a condenser  406 , an expansion device  407 , and an evaporator  408 . A refrigerant compressed by the compressor  405  may be discharged in a liquid state having a high temperature and a high pressure while passing through the condenser  406 , and may be discharged in a vapor state having a low temperature and a low pressure while passing through the expansion device  407  and the evaporator  408 , and then be introduced once again to the compressor  405 . 
         [0136]    The second cooling apparatus  400  may be provided to lower temperatures inside the freezing compartment  402  and the converting compartment  403  to a target temperature. 
         [0137]    The second cooling apparatus  400  may include a first refrigerant circuit, a second refrigerant circuit, and a third refrigerant circuit. 
         [0138]    In the first refrigerant circuit, a refrigerant discharged from a compressor  410  may flow to a suction side of the compressor  410  through a condenser  420 , an ejector  430 , and a vapor liquid separator  440 . In the second refrigerant circuit, a refrigerant may be sucked into an inlet of the ejector  430  to be circulated by passing through the ejector  430 , the vapor liquid separator  440 , a first expansion device  452 , a first evaporator  454  and a second evaporator  464 . In the third refrigerant circuit, the refrigerant passing through the vapor liquid separator  440  may be sucked into an inlet of the ejector  430  by passing through a second expansion device  462  and the second evaporator  464  to bypass the first expansion device  452  and the first evaporator  454 . 
         [0139]    Use of the first evaporator  454  and the second evaporator  464  are not limited thereto, but according to one embodiment of the present disclosure, the first evaporator  454  may be used in the converting compartment  403  of the refrigerator, and the second evaporator  464  may be used in the freezing compartment  460  of the refrigerator. That is, the first evaporator  454  may be referred to as the converting compartment evaporator and the second evaporator  464  may be referred to as a freezing compartment evaporator. 
         [0140]    A flow path switching device  470  may control the amount of refrigerant flow between the second refrigerant circuit and the third refrigerant circuit. Particularly, the flow path switching device  470  may be installed in a discharge side of the vapor liquid separator  440  to switch a flow path so that a liquid refrigerant passed through the vapor liquid separator  440  may pass at least one of the second and the third refrigerant circuit. 
         [0141]    The flow path switching device  470  may include a three way valve. The flow path switching device  470  may include a first valve  471  opening/closing the second refrigerant circuit and a second valve  472  opening/closing the third refrigerant circuit. 
         [0142]    A condenser fan motor  422  driving a condenser fan  421 , a first fan motor  458  driving a first fan  457  of the converting compartment  403 , and a second fan motor  468  driving a second fan  467  of the freezing compartment  460  may be further provided. 
         [0143]    A first defrost heater  456  and a second defrost heater  466  may be provided in the first evaporator  454  and the second evaporator  464  to remove frost on surface of the evaporators 
         [0144]    As is apparent from the above description, by allowing a liquid refrigerant to sufficiently flow in the evaporator, a cooling capacity may be improved, and the amount of work of compression may be reduced by increasing a pressure of a suction refrigerant of the compressor. 
         [0145]    By changing a refrigerant flow according to modes, a cooling efficiency and a freezing efficiency may be improved. 
         [0146]    By improving a structure of the cooling apparatus, Coefficient of Performance (COP) may be improved. 
         [0147]    Although a few embodiments of the present disclosure have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.