Abstract:
A header unit includes a body and a cover coupled to the body. The body supports outer and inner sides of the cover in a simultaneous manner. In accordance with this structure, refrigerant can flow in a heat exchanger for cooling/heating purposes requiring high operating pressure of refrigerant.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 2010-106370 filed on Oct. 28, 2010 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments of the present disclosure relate to a header unit, and, more particularly, to a header unit made of an aluminum material. 
         [0004]    2. Description of the Related Art 
         [0005]    An air conditioner is a system configured to control heat and humidity of ambient air. Heat exchange of such an air conditioner with ambient air is achieved by a simple refrigeration cycle. 
         [0006]    The refrigeration cycle may include a compressor, a condenser, an expansion valve, and an evaporator. High-temperature and high-pressure refrigerant emerging from the compressor exchanges heat with outdoor air while passing through the condenser, so that it is changed into a low temperature state. The refrigerant is then changed into a low-temperature and low-pressure state while passing through the expansion valve. The low-temperature and low-pressure refrigerant subsequently exchanges heat with indoor air while passing through the evaporator, so that the indoor air is cooled. 
         [0007]    Heat exchangers are classified into a heat exchanger for a vehicle and a domestic heat exchanger in accordance with the installation place thereof. The vehicle heat exchanger and domestic heat exchanger are different from each other in terms of the kind of refrigerant used therein and the operation environments of the installation place thereof such as air flow and air velocity. For this reason, these heat exchangers have different design factors in terms of material and size, in order to obtain optimal heat exchange efficiencies. 
       SUMMARY 
       [0008]    It is an aspect of the present disclosure to provide a heat exchanger made of an aluminum material. 
         [0009]    It is another aspect of the present disclosure to provide a heat exchanger which is made of an aluminum material, and has a structure capable of efficiently distributing refrigerant. 
         [0010]    It is another aspect of the present disclosure to provide a heat exchanger which is made of an aluminum material, and has a structure capable of securing a desired internal pressure of refrigerant. 
         [0011]    It is another aspect of the present disclosure to provide a heat exchanger which is made of an aluminum material, and has a structure capable of avoiding corrosion and securing desired stiffness. 
         [0012]    It is still another aspect of the present disclosure to provide a heat exchanger which is made of an aluminum material, and has a structure capable of achieving an enhancement in drainage performance. 
         [0013]    In accordance with one aspect of the present disclosure, a header unit includes a body, and a cover coupled to the body, wherein the body supports outer and inner sides of the cover in a simultaneous manner. 
         [0014]    The body may include a base and a seating groove provided at the base. The cover may include a support portion and a side wall portion provided at the support portion. At least a part of the side wall portion of the cover may be fitted in the seating groove of the body. 
         [0015]    The seating groove of the body may include outer and inner side wall portions protruded from the base. The outer side wall portion may be protruded to a higher level than the inner side wall portion. 
         [0016]    The body may further include an intermediate barrier wall protruded from the base. The intermediate barrier wall of the body may be coupled to the support portion of the cover in a caulking fashion. 
         [0017]    The header unit may further include a plurality of partition plates installed at the body and the cover while being arranged in a longitudinal direction of the body and the cover, and at least one of the partition plates is inserted into the intermediate barrier wall of the body. 
         [0018]    The header unit may further include a plurality of tubes fitted in the support portion of the cover. Stoppers to set respective insertion positions of the tubes may be formed at the intermediate barrier wall of the body. 
         [0019]    The header unit may further include a plurality of tubes fitted in the support portion of the cover. Each of the tubes may be maintained to be spaced apart from the intermediate barrier wall by a predetermined gap before a coupling process for the tubes. The gap may be filled up by a clad material in the coupling process. 
         [0020]    The header unit may be made of an aluminum material. 
         [0021]    A refrigerant introduction pipe may be connected to at least a portion of the header unit. The refrigerant introduction pipe may be made of a copper material. A connecting pipe made of a stainless steel material may be arranged between the header unit and the refrigerant introduction pipe. 
         [0022]    A refrigerant introduction pipe may be connected to at least a portion of the header unit. The refrigerant introduction pipe may be made of a copper material. The refrigerant introduction pipe may be provided with a reinforcing member enclosing the refrigerant introduction pipe, to be firmly supported by the header unit. 
         [0023]    A refrigerant discharge pipe may be connected to at least a portion of the header unit. The refrigerant discharge pipe may be made of a copper material. A connecting pipe made of a stainless steel material may be arranged between the header unit and the refrigerant discharge pipe. 
         [0024]    A refrigerant discharge pipe may be connected to at least a portion of the header unit. The refrigerant discharge pipe may be made of a copper material. The refrigerant discharge pipe may be provided with a reinforcing member enclosing the refrigerant discharge pipe, to be firmly supported by the header unit. 
         [0025]    An R-22 or R-410A-series refrigerant may flow in the header unit. 
         [0026]    In accordance with another aspect of the present disclosure, a heat exchanger includes a pair of header units, and a pair of heat exchanging units arranged between the header units, wherein each of the header units includes a body, and a cover coupled to the body, wherein the body supports outer and inner sides of the cover in a simultaneous manner. 
         [0027]    Each of the header units may further include a plurality of partition plates fitted in the body and the cover to partition the header unit into a plurality of portions. 
         [0028]    The header units and the heat exchanging units may be made of an aluminum material. 
         [0029]    An R-22 or R-410A-series refrigerant may flow in the header units and the heat exchanging units. 
         [0030]    The heat exchanger may further include at least one refrigerant circuit to define at least one refrigerant path through which refrigerant introduced into one of the header units is discharged out of the header unit after exchanging heat in the heating exchanging units. 
         [0031]    In accordance with another aspect of the present disclosure, a header unit includes a body, and a cover coupled to the body, wherein at least a portion of the body supports an end of the cover. 
         [0032]    The at least a portion of the body may be provided with a seating groove to support outer and inner sides of the end of the cover in a simultaneous manner. 
         [0033]    The seating groove may include outer and inner side wall portions to support the outer and inner sides of the end of the cover, respectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]    These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0035]      FIG. 1  is a perspective view illustrating a heat exchanger according to an exemplary embodiment of the present disclosure; 
           [0036]      FIG. 2  is an exploded perspective view illustrating a structure of the first header unit according to an exemplary embodiment of the present disclosure; 
           [0037]      FIG. 3  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a refrigerant introduction pipe according to an exemplary embodiment of the present disclosure is coupled; 
           [0038]      FIG. 4  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a refrigerant discharge pipe according to an exemplary embodiment of the present disclosure is coupled; 
           [0039]      FIG. 5  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a partition plate according to an exemplary embodiment of the present disclosure is coupled; 
           [0040]      FIG. 6  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a tube according to an exemplary embodiment of the present disclosure is coupled; 
           [0041]      FIG. 7  is an exploded perspective view illustrating a structure of the second header unit according to an exemplary embodiment of the present disclosure; 
           [0042]      FIG. 8  is a sectional view illustrating a portion of the second header unit of  FIG. 7  at which a through hole according to an exemplary embodiment of the present disclosure is formed; 
           [0043]      FIG. 9  is a sectional view illustrating a portion of the first header unit of  FIG. 7  to which a partition plate according to an exemplary embodiment of the present disclosure is coupled; 
           [0044]      FIG. 10  is a sectional view illustrating tube structures of the first and second heat exchanging units according to an exemplary embodiment of the present disclosure; 
           [0045]      FIG. 11  is a perspective view illustrating fin structures of the first and second heat exchanging units according to an exemplary embodiment of the present disclosure; 
           [0046]      FIGS. 12 and 13  are sectional views illustrating a refrigerant introduction pipe according to another exemplary embodiment of the present disclosure; 
           [0047]      FIG. 14  is a perspective view illustrating a heat exchanger according to another exemplary embodiment of the present disclosure; 
           [0048]      FIGS. 15 and 16  are sectional views illustrating a first structure of a first header unit included in the heat exchanger of  FIG. 14 ; 
           [0049]      FIGS. 17 and 18  are sectional views illustrating a second structure of the first header unit included in the heat exchanger of  FIG. 14 ; and 
           [0050]      FIG. 19  is a schematic view illustrating refrigerant flows in the heat exchanger according to an exemplary embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0051]    Hereinafter, a heat exchanger according to an exemplary embodiment of the present disclosure will be described with reference to the accompanying drawings. 
         [0052]    The following description will be given in conjunction with a Kimchi refrigerator to store salted food, etc., as the refrigerator according to the embodiment of the present disclosure. 
         [0053]      FIG. 1  is a perspective view illustrating a heat exchanger according to an exemplary embodiment of the present disclosure. 
         [0054]    As shown in  FIG. 1 , the heat exchanger, which is designated by reference numeral  1 , may be used to exchange heat with indoor air. In particular, the heat exchanger  1  may be an evaporator (or condenser) installed in a building. In this case, the heat exchanger  1  is distinguished from a heat exchanger installed in a vehicle. In the case of a heat exchanger installed in a vehicle, a refrigerant for a vehicle heat exchanger such as R-12 or R-134a (Maximum operating pressure only for cooling×3: 60-70 kg/cm 2 ) is used. In the case of the heat exchanger  1  shown in  FIG. 1 , however, a refrigerant for a domestic heat exchanger such as R-22 or R-410A (Maximum operating pressure for cooling/heating×3: 130-140 kg/cm 2 ) is used. The two heat exchangers have different shapes and structures in that they use different gas pressures because they use different kinds of refrigerant and have different functions, namely, a cooling function and a cooling/heating function, respectively. The following description will be given of the heat exchanger  1 , which is made of an aluminum material and uses a refrigerant for a domestic air conditioner such as R-22 or R-410A. 
         [0055]    The heat exchanger  1  includes a pair of header units  10  and  20 , and a pair of heat exchanging units  30  and  40  arranged between the header units  10  and  20 . The header units  10  and  20  are horizontally arranged, whereas the heat exchanging units  30  and  40  are vertically arranged. Hereinafter, the header unit  10 , which is arranged at a lower position, is referred to as a first header unit, whereas the header unit  20 , which is arranged at an upper position, is referred to as a second header unit. On the other hand, the heat exchanging unit  30 , which is arranged at a front side, is referred to as a first heat exchanging unit, whereas the heat exchanging unit  40 , which is arranged at a rear side, is referred to as a second heat exchanging unit. 
         [0056]      FIG. 2  is an exploded perspective view illustrating a structure of the first header unit according to an exemplary embodiment of the present disclosure.  FIG. 3  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a refrigerant introduction pipe according to an exemplary embodiment of the present disclosure is coupled.  FIG. 4  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a refrigerant discharge pipe according to an exemplary embodiment of the present disclosure is coupled.  FIG. 5  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a partition plate according to an exemplary embodiment of the present disclosure is coupled.  FIG. 6  is a sectional view illustrating a portion of the first header unit of  FIG. 2  to which a tube according to an exemplary embodiment of the present disclosure is coupled. 
         [0057]    As shown in  FIGS. 1 to 6 , the first header unit  10  may include a body  50 , a cover  60 , and a plurality of partition plates  70 . 
         [0058]    The body  50  may be formed to substantially have a “ω” shape. In detail, the body  50  may include a base  51 , seating grooves  52 , an intermediate barrier wall  53 , and stoppers  54 . 
         [0059]    The cover  60  may be formed to substantially have an “inverted U”-shape. In detail, the cover  60  may include a support portion  61  and side wall portions  62 . 
         [0060]    The intermediate barrier wall  53  of the body  50  is upwardly protruded from a central portion of the base  51  of the body  50 , and is inserted into the support portion  61  of the cover  60 . An upper end of the intermediate barrier wall  53  is outwardly protruded from the support portion  61 , and is then coupled with the support portion  61  in a caulking fashion. Thus, the intermediate barrier wall  53  divides the first header unit  10  into a first header  11  and a second header  12 , which are sealed from each other. In accordance with the caulking type coupling structure, it may be possible to secure desired stiffness against internal pressure of refrigerant between the intermediate barrier wall  53  and the support portion  61 . 
         [0061]    The side wall portions  62  of the cover  60  are structured to be fitted in respective seating grooves  52  of the body  50 . That is, each seating groove  52  of the body  50  includes an outer side wall portion  52   a  and an inner side wall portion  52   b  to define a groove having a certain depth. Each side wall portion  62  is fitted between the outer and inner side wall portions  52   a  and  52   b  of the corresponding seating groove  52 . Thus, the outer and inner side wall portions  52   a  and  52   b  of each seating groove  52  in the body  50  support outer and inner surfaces of a free end part of the corresponding side wall portion  62  in the cover  60 , respectively. The outer side wall portion  52   a  is upwardly protruded to a higher level than the inner side wall portion  52   b . Since the body  50  has a structure capable of supporting both the outer and inner surfaces of the cover  60 , it may be possible to secure desired stiffness against the inner pressure of refrigerant. 
         [0062]    Tubes  31  and tubes  41  are fitted in left and right side regions of the support portion  61  in the cover  60 , respectively. Since the tubes  31  and  41  have the same structure, the following description will be given only in conjunction with the tubes  31  for simplicity of description. Each tube  31  is inserted into the support portion  61  until they come into contact with the corresponding stopper  54  formed at the intermediate barrier wall  53 . Thus, the installation position of each tube  31  is set. Each tube  31  may be spaced apart from the intermediate barrier wall  53  by a predetermined gap G. The gap G maintained between the tube  31  and the intermediate barrier wall  53  before a brazing process may be 0.2 to 0.3 mm. This gap G is filled up by a clad material in the brazing process. As a result, the coupling force between the intermediate barrier wall  53  and the tube  31  increases, so that desired stiffness against the inner pressure of refrigerant may be secured. 
         [0063]    Partition plates  70  are installed at opposite ends of the first header  11  to seal the first header  11 . Another partition plate  70  is also installed at a central region of the first header  11 . As a result, the first header  11  is partitioned into two tanks  11   a  and  11   b . A group of tubes  31 , which are included in the first heat exchanging unit  30 , are connected to each of the first and second tanks  11   a  and  11   b . Thus, refrigerant flows in the first header  11  in the form of a plurality of flows separated from one another by a plurality of partition plates  70 . 
         [0064]    Similarly, partition plates  70  are installed at opposite ends of the second header  12  to seal the second header  12 . The second header  12  is partitioned into a single tank  12   a . Accordingly, all tubes  41  of the second heat exchanging unit  40  are connected to the tank  12   a  of the second header  12 . Thus, refrigerant flows in the second header  12  in the form of a unified flow. In this case, accordingly, it may be possible to simplify the overall structure and to reduce the manufacturing costs. In particular, the heat exchanger  1  may have a compact structure because the second header  12  communicates with a single refrigerant discharge pipe  90 . 
         [0065]    Meanwhile, an additional partition plate  70  is installed at the first header  11  adjacent to the partition plate  70  arranged at one end of the first header  11  (the right end in the illustrated case) while being spaced apart from the adjacent partition plate  70 . The intermediate barrier wall  53  is partially removed in a region between the adjacent partition plates  70  of the first header  11  in order to allow a space defined between the adjacent partition plates  70  to communicate with the second header  12  ( FIG. 4 ). The refrigerant discharge pipe  90  is connected to a portion of the first header unit  10  at which the first and second headers  11  and  12  communicate with each other through the removed portion of the intermediate barrier wall  53 . 
         [0066]    Each partition plate  70  is structured such that at least a portion thereof is fitted in the intermediate barrier wall  53 . In accordance with this structure, it may be possible to increase the coupling force between the partition plate  70  and the intermediate barrier wall  53 , thereby securing refrigerant sealing effects and achieving an increase in stiffness against internal pressure. 
         [0067]    A plurality of refrigerant introduction pipes is installed at respective tanks of the first header  11 . In the illustrated case, two refrigerant introduction pipes  81  and  82  are provided. In detail, the first refrigerant introduction pipe  81  is connected to the first tank  11   a  of the first header  11 , whereas the second refrigerant introduction pipe  82  is connected to the second tank  11   b  of the first header  11 . Practically, each of the refrigerant introduction pipes  81  and  82  is fitted through one side wall portion  62  of the cover  60  in the first header  11 . A first connecting pipe  83  may be fitted between each of the refrigerant introduction pipes  81  and  82  and the side wall portion  62  of the cover  60 . Since the refrigerant introduction pipes  81  and  82  are made of a copper material whereas the cover  60  is made of an aluminum material, the first connecting pipe  83 , which is made of a stainless steel material, is interposed between each of the refrigerant introduction pipes  81  and  82  and the cover  60  in order to prevent promoted corrosion of the different materials (the copper and aluminum materials) that may occur when the copper and aluminum materials come into contact with each other. 
         [0068]    A first reinforcing member  84  is provided at the side wall portion  62  of the cover  60  to support each of the refrigerant introduction pipes  81  and  82 . Thus, each of the refrigerant introduction pipes  81  and  82  is firmly supported by the side wall portion  62  of the cover  60 . The first reinforcing member  84  is made of an aluminum material. Accordingly, another first connecting pipe  83  is also provided between the first reinforcing member  84 , which is made of an aluminum material, and each of the refrigerant introduction pipes  81  and  82 , which are made of a copper material. 
         [0069]    The refrigerant discharge pipe  90  is arranged in a region adjacent to the right ends of the first and second headers  11  and  12 . In more detail, the refrigerant discharge pipe  90  is installed at a central region in the support portion  61  of the cover  60 . Since the intermediate barrier wall  53  is partially removed from a region beneath the refrigerant discharge pipe  90 , the first and second headers  11  and  12  communicate with each other in the region. The refrigerant discharge pipe  90  has a larger diameter than the refrigerant introduction pipes  81  and  82 , in order to prevent loss of pressure caused by an increase in the volume of refrigerant occurring when the refrigerant is changed from a liquid phase to a gas phase during heat exchange. As a result, it may be possible to reduce the flow resistance of the refrigerant, and thus to allow the refrigerant to flow smoothly. Since only one refrigerant discharge pipe  90  is provided at one side of the first header unit  10 , the heat exchanger  1  may have a compact structure. 
         [0070]    A second connecting pipe  91  may be fitted between the refrigerant discharge pipe  90  and the support portion  61  of the cover  60 . Since the refrigerant discharge pipe  90  is made of a copper material whereas the cover  60  is made of an aluminum material, the second connecting pipe  91 , which is made of a stainless steel material, is interposed between the refrigerant discharge pipe  90  and the cover  60  in order to prevent promoted corrosion of the different materials (the copper and aluminum materials) that may occur when the copper and aluminum materials come into contact with each other. 
         [0071]    A second reinforcing member  92  is provided at the support portion  61  of the cover  60  to support the refrigerant discharge pipe  90 . Thus, the refrigerant discharge pipe  90  is firmly supported by the support portion  61  of the cover  60 . The second reinforcing member  92  is made of an aluminum material. Accordingly, another second connecting pipe  91  is also provided between the second reinforcing member  92 , which is made of an aluminum material, and the refrigerant discharge pipe  90 , which is made of a copper material. 
         [0072]      FIG. 7  is an exploded perspective view illustrating a structure of the second header unit according to an exemplary embodiment of the present disclosure.  FIG. 8  is a sectional view illustrating a portion of the second header unit of  FIG. 7  at which a through hole according to an exemplary embodiment of the present disclosure is formed.  FIG. 9  is a sectional view illustrating a portion of the first header unit of  FIG. 7  to which a partition plate according to an exemplary embodiment of the present disclosure is coupled. 
         [0073]    As shown in  FIGS. 1 to 9 , the second header unit  20  may include a body  50 , a cover  60 , and a plurality of partition plates  70 . 
         [0074]    The body  50  may be formed to substantially have a “ω” shape. In detail, the body  50  may include a base  51 , seating grooves  52 , an intermediate barrier wall  53 , and stoppers  54 . The cover  60  may be formed to substantially have a “inverted U”-shape. In detail, the cover  60  may include a support portion  61  and side wall portions  62 . Hereinafter, the second header unit  20  will be described in conjunction with portions different from those of the body  50  and cover  60  in the first header unit  10 , except for the same portions as the first header unit  10 . 
         [0075]    The intermediate barrier wall  53  of the body  50  divides the second header unit  20  into a third header  21  and a fourth header  22 , which are sealed from each other. Of course, a plurality of through holes  53   a  is formed through the intermediate barrier wall  53  to be arranged in a longitudinal direction of the intermediate barrier wall  53 . Accordingly, refrigerant may flow from the third header  21  to the fourth header  22  through the plural through holes  53   a.    
         [0076]    Partition plates  70  are installed at opposite ends of the third header  21  to seal the third header  21 . Another partition plate  70  is also installed at a central region of the third header  21 . As a result, the third header  21  is partitioned into two tanks  21   a  and  21   b . A group of tubes  31 , which are included in the first heat exchanging unit  30 , are connected to each of the first and second tanks  21   a  and  21   b . Thus, refrigerant flows in the third header  21  in the form of a plurality of flows separated from one another by a plurality of partition plates  70 . 
         [0077]    Similarly, partition plates  70  are installed at opposite ends of the fourth header  22  to seal the fourth header  22 . Another partition plate  70  is also installed at a central region of the fourth header  22 . As a result, the fourth header  22  is partitioned into two tanks  22   a  and  22   b . A group of tubes  41 , which are included in the second heat exchanging unit  40 , are connected to each of the first and second tanks  22   a  and  22   b . Thus, refrigerant flows in the fourth header  22  in the form of a plurality of flows separated from one another by a plurality of partition plates  70 . 
         [0078]    Thus, each of the third and fourth headers  21  and  22  is divided into a plurality of header portions defining a plurality of connecting passages to connect the first and second heat exchanging units  30  and  40 . 
         [0079]      FIG. 10  is a sectional view illustrating tube structures of the first and second heat exchanging units according to an exemplary embodiment of the present disclosure.  FIG. 11  is a perspective view illustrating fin structures of the first and second heat exchanging units according to an exemplary embodiment of the present disclosure. 
         [0080]    As shown in  FIGS. 1 to 11 , the first heat exchanging unit  30  may include a plurality of tubes  31  and fins  35 , and the second heat exchanging unit  40  may include a plurality of tubes  41  and fins  35 . Since the tubes  31  and  41  have the same structure, the following description will be given only in conjunction with the tubes  31 , for simplicity of description. 
         [0081]    Each tube  31  has a planar structure having a plurality of microchannels  32 . The number of microchannels  32  in each tube  31  may be about 6 to 10. Each tube  31  may have a width W of 7 to 13 mm, and a height H of 2 to 3 mm. The spacing S between the adjacent microchannels may be 0.7 to 0.8 mm. 
         [0082]    Each fin  35  is arranged between the adjacent tubes  31 . Each fin  35  has a corrugated structure. In this case, the corrugated structure is formed by alternately and repeatedly bending the fin  35  through about 90° to form successive bent portions spaced apart from one another by a certain distance. That is, the fin  35  is structured to be perpendicularly protruded from the corresponding tubes  31 . The fin  35  is coupled to the corresponding tubes  31  through a brazing process. In the brazing process, fillets  36  are formed at contact regions between the fin  35  and each tube  31 . 
         [0083]    Louvers  37  are formed at each fin  35 . The louvers  37  function to enhance heat exchange efficiency and easy drainage. That is, the louvers  37  generate turbulent air flows to increase the contact time and area of the fin  35  with air, thereby achieving an enhancement in heat exchange efficiency. Also, the louvers  37  reduce the surface tension of condensed water, thereby achieving an enhancement in drainage performance. 
         [0084]      FIGS. 12 and 13  are sectional views illustrating a refrigerant introduction pipe according to another exemplary embodiment of the present disclosure. As shown in  FIGS. 12 and 13 , the refrigerant introduction pipes  81  and  82  may be coupled to the first header  11  of the first header unit  10  to form an integrated structure. That is, the refrigerant introduction pipes  81  and  82 , which are made of an aluminum material, may be coupled to the first header  11  of the first header unit  10 , which is made of an aluminum material through a brazing process. 
         [0085]    Each of the refrigerant introduction pipes  81  and  82  may include a vertical portion  85   a , a horizontal portion  85   b , and a bent portion  85   c  to connect the vertical portion  85   a  and horizontal portion  85   b.    
         [0086]    The horizontal portion  85   b  of the first refrigerant introduction pipe  81  corresponds to the first tank  11   a  of the first header  11 , whereas the horizontal portion  85   b  of the second refrigerant introduction pipe  82  corresponds to the second tank  11   b  of the first header  11 . 
         [0087]    The vertical portion  85   a  of each of the refrigerant introduction pipes  81  and  82  is connected to a refrigerant line (not shown) made of a copper material. Of course, a connecting pipe made of a stainless steel material may be interposed to prevent promoted corrosion of the different materials (the copper and aluminum materials) that may occur when the copper and aluminum materials come into contact with each other. Meanwhile, the vertical portion  85   a  has a smaller diameter than the horizontal portion  85   b . In particular, this diameter difference is abrupt at the bent portion  85   c . The bent portion  85  may function as a factor to obstruct smooth distribution of refrigerant because it abruptly changes the flow direction of the refrigerant from a vertical direction to a horizontal direction. 
         [0088]    To this end, a diffusion member  86  is installed at a portion of the horizontal portion  85   b  adjacent to the vertical portion  85   a  in order to appropriately distribute the refrigerant flowing from the vertical portion  85   a  to the horizontal portion  85   b . The diffusion member  86  may have a circular protrusion structure. Alternatively, the diffusion member  86  may be installed at a portion of the vertical portion  85   a  adjacent to the horizontal portion  85   b.    
         [0089]    A plurality of introduction pipe guide members  87  may be installed at the horizontal portion  85   b  to guide the refrigerant appropriately distributed by the diffusion member  86 . The plural introduction pipe guide members  87  appropriately distribute the refrigerant to a corresponding one of the tanks  11   a  and  11   b  of the first header  11  in the first header unit  10 . The refrigerant appropriately distributed in the corresponding one of the tanks  11   a  and  11   b  of the first header  11  in the first header unit  10  then flows to the tubes  31  of the first heat exchanging unit  30 . 
         [0090]      FIG. 14  is a perspective view illustrating a heat exchanger according to another exemplary embodiment of the present disclosure.  FIGS. 15 and 16  are sectional views illustrating a first structure of a first header unit included in the heat exchanger of  FIG. 14 . 
         [0091]    As shown in  FIGS. 14 to 16 , a plurality of refrigerant introduction pipes, for example, refrigerant introduction pipes  81  and  82 , and a refrigerant discharge pipe  90  may be installed together at the right end of a heat exchanger  2 . 
         [0092]    A first header  11  included in a first header unit  10  communicates with the refrigerant introduction pipes  81  and  82 . The first header  11  includes a first tank  11   a  to communicate with the first refrigerant introduction pipe  81 , and a second tank  11   b  to communicate with the second refrigerant introduction pipe  82 . The first and second tanks  11   a  and  11   b  are separated from each other by a horizontal partition plate  71  and vertical partition plates  72  provided at opposite sides of the horizontal partition plate  71 . A group of tubes  31   a , which define refrigerant paths, are connected to the first tank  11   a . Also, a group of tubes  31   b , which define refrigerant paths, are connected to the second tank  11   b.    
         [0093]    A second header  12  included in the first header unit  10  communicates with the refrigerant discharge pipe  90 . The second header  12  includes a single tank  12   a  to communicate with the refrigerant discharge pipe  90 . 
         [0094]    Heretofore, the heat exchanger  2  shown in  FIG. 14  has been described in conjunction with portions different from those of the heat exchanger  1  shown in  FIG. 1 . No description will be given of the same portions of the heat exchanger  2  of  FIG. 14  as the heat exchanger  1  of  FIG. 1 . 
         [0095]      FIGS. 17 and 18  are sectional views illustrating a second structure of the first header unit included in the heat exchanger of  FIG. 14 . 
         [0096]    As shown in  FIGS. 14 ,  17 , and  18 , a plurality of refrigerant introduction pipes, for example, refrigerant introduction pipes  81  and  82 , and a refrigerant discharge pipe  90  may be installed together at the right end of the heat exchanger  2 . 
         [0097]    A first header  11  included in a first header unit  10  communicates with the refrigerant introduction pipes  81  and  82 . The first header  11  includes a first tank  11   a  to communicate with the first refrigerant introduction pipe  81 , and a second tank  11   b  to communicate with the second refrigerant introduction pipe  82 . The first and second tanks  11   a  and  11   b  are separated from each other by partition plates  70 . The first header  11  also includes a first refrigerant passage  14   a  extending from the first refrigerant introduction pipe  81  to the first tank  11   a , and a second refrigerant passage  14   b  extending from the second refrigerant introduction pipe  82  to the second tank  11   b . The first and second refrigerant passages  14   a  and  14   b  are formed in accordance with an extrusion molding process. 
         [0098]    A second header  12  included in the first header unit  10  communicates with the refrigerant discharge pipe  90 . The second header  12  includes a single tank  12   a  to communicate with the refrigerant discharge pipe  90 . 
         [0099]    Heretofore, the heat exchanger  2  shown in  FIG. 17  has been described in conjunction with portions different from those of the heat exchanger  1  shown in  FIG. 1 . No description will be given of the same portions of the heat exchanger  2  of  FIG. 17  as the heat exchanger  1  of  FIG. 1 . 
         [0100]    Hereinafter, operation and coupling of the heat exchanger according to an exemplary embodiment of the present disclosure will be described in conjunction with the accompanying drawings. 
         [0101]      FIG. 19  is a schematic view illustrating refrigerant flows in the heat exchanger according to an exemplary embodiment of the present disclosure. 
         [0102]    As shown in  FIGS. 1 to 19 , the heat exchanger includes a plurality of refrigerant circuits. 
         [0103]    The plurality of refrigerant circuits may include a first refrigerant circuit  101  and a second refrigerant circuit  102 . The first refrigerant circuit  101  is a refrigerant path through which refrigerant introduced into the first refrigerant introduction pipe  81  is discharged through the refrigerant discharge pipe  90  after passing through the first tank  11   a  of the first header  11 , the grouped tubes  31  of the first heat exchanging unit  30 , the first tank  21   a  of the third header  21 , the first tank  22   a  of the fourth header  22 , the grouped tubes  41  of the second heat exchanging unit  40 , and the second header  12 . The second refrigerant circuit  102  is a refrigerant path through which refrigerant introduced into the second refrigerant introduction pipe  82  is discharged through the refrigerant discharge pipe  90  after passing through the second tank  11   b  of the first header  11 , the grouped tubes  31  of the first heat exchanging unit  30 , the second tank  21   b  of the third header  21 , the second tank  22   b  of the fourth header  22 , the grouped tubes  41  of the second heat exchanging unit  40 , and the second header  12 . 
         [0104]    As a plurality of refrigerant circuits, for example, the refrigerant circuits  101  and  102 , are provided, it may be possible to achieve efficient refrigerant distribution, and thus to achieve an enhancement in heat exchange efficiency. Separate refrigerant flows may be defined in accordance with the provision of a plurality of refrigerant introduction pipes, for example, the refrigerant introduction pipes  81  and  82 . Accordingly, even when the heat exchanger has an increased height, it may be possible to reliably supply refrigerant up to an uppermost portion of the heat exchanger, and thus to enhance operation reliability. 
         [0105]    Since the second header  12 , which is partitioned into the single tank  12   a , communicates with the single refrigerant discharge pipe  90 , it may be possible to simplify the structure of the second header  12  and the structure of the refrigerant discharge pipe  90 . Also, the refrigerant discharge pipe  90  is arranged at one end of the first header unit  10 . Accordingly, the heat exchanger has a compact structure. 
         [0106]    Meanwhile, in accordance with another embodiment, each of the first header  11  of the first header unit  10  and the third header  21  and fourth header  22  of the second header unit  20  may be partitioned into a single tank. In this case, the heat exchanger may include a single refrigerant circuit. 
         [0107]    In accordance with another embodiment, each of the first header  11  of the first header unit  10  and the third header  21  and fourth header  22  of the second header unit  20  may be partitioned into three or more tanks. In this case, the heat exchanger may include three or more refrigerant circuits. 
         [0108]    In accordance with another embodiment, the first refrigerant circuit  101  and second refrigerant circuit  102  may have opposite refrigerant flow directions, respectively. 
         [0109]    Meanwhile, the heat exchanger is made of an aluminum material. That is, the first header unit  10 , second header unit  20 , first heat exchanging unit  30 , and second heat exchanging unit  40  are made of an aluminum material, and are coupled together through a brazing process. 
         [0110]    In particular, in the case of a domestic heat exchanger, standard fracture pressure corresponds to 3 times maximum operating pressure. That is, the internal pressure design standard for refrigerant used in such a domestic heat exchanger, such as R-22 or R-410A, corresponds to 130-140 kg/cm 2  when the heat exchanger is used for cooling/heating. In order to satisfy this internal pressure design standard, the outer side wall portion  52   a  and inner side wall portion  52   b  of the body  50  are structured to simultaneously support the outer and inner surfaces of the side wall portion  62  of the cover  60 . The heat exchanger also has a structure in which, when each partition plate  70  is coupled to the body  50  and cover  60 , at least a portion of the partition plate  70  is fitted in the intermediate barrier wall  53 . In addition, a cladding material is filled in the gap G between each tube  31  and the intermediate barrier wall  53  in the brazing process. Thus, the tube  31  may be firmly supported. 
         [0111]    Meanwhile, the connecting pipes  83  and  91  are interposed between the first header unit  10 , which is made of an aluminum material, and each of the refrigerant introduction pipes  81  and  82 , which are made of a copper material, and between the first header unit  10  and the refrigerant discharge pipe  90 , which is made of a copper material, respectively. Accordingly, it may possible to prevent promoted corrosion of the different materials (the copper and aluminum materials) that may occur when the copper and aluminum materials come into contact with each other. In addition, the reinforcing members  84  and  92  enclose each of the refrigerant introduction pipes  81  and  82  and the refrigerant discharge pipe  90 , to firmly support the corresponding pipes, respectively. 
         [0112]    As apparent from the above description, in accordance with one aspect of the present disclosure, it may be possible to provide a heat exchanger capable of achieving an improvement in refrigerant distribution, thereby achieving a remarkable enhancement in heat exchange efficiency. 
         [0113]    Also, the heat exchanger may secure operation reliability and stiffness against refrigerant gas pressure while reducing manufacturing costs. 
         [0114]    In addition, the heat exchanger may have a compact structure, so that the installation space thereof may be minimized. Thus, it may be possible to provide a compact air conditioner. 
         [0115]    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 invention, the scope of which is defined in the claims and their equivalents.