Patent Publication Number: US-9885522-B2

Title: Heat exchanger and case for the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from Korean Patent Application No. 10-2013-0079910, filed on Jul. 8, 2013, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Field 
     Apparatuses consistent with exemplary embodiments relate to a heat exchanger and a case for the heat exchanger, and more particularly, to a heat exchanger and a case for the heat exchanger with improved heat exchange performance and compact structure. 
     2. Description of the Related Art 
     Heat exchangers are used to exchange heat between heat transfer media having different temperatures by directly or indirectly contacting each other, and such heat exchangers are applied to various fluid mechanical systems such as heat engines or cooling systems. 
     To cool fluids that are used in a fluid mechanical system such as a multi-stage compressor having a plurality of compression stages, a heat exchanger is also designed to have a plurality of heat exchange chambers corresponding to the number of the respective compression stages. However, in a heat exchanger of the related art including a plurality of heat exchange chambers, each chamber having a chamber wall, a distance between adjacent heat exchange chambers is quite long, so the overall size of the heat exchanger is increased. 
     Furthermore, although each heat exchange chamber has a higher temperature region and a lower temperature region, the heat exchanger of the related art is designed without considering the thermal characteristics of the different regions of the heat exchange chambers, so the heat exchanger of the related art has a limitation on improving heat exchange performance. 
     The heat exchanger of the related art is also configured such that a passage through which a heat exchange fluid exchanging heat is circulated into a heat exchange chamber projects out from the heat exchange chamber, thereby increasing the overall size of the heat exchanger. Furthermore, since an oil passageway through which oil used for lubrication or other purposes passes is disposed in the heat exchanger without considering thermal characteristics of the heat exchanger, the heat exchanger of the related art has a limitation with respect to the heat exchange performance. 
     SUMMARY 
     One or more exemplary embodiments provide a heat exchanger and a case for the heat exchanger adapted to provide improved heat exchange performance and the heat exchanger having a compact structure and a reduced overall size. 
     One or more exemplary embodiments provide a heat exchanger and a case for the heat exchanger designed in consideration of thermal characteristics of a plurality of chambers where heat exchange occurs. 
     Additional aspects 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 exemplary embodiments. 
     According an aspect of an exemplary embodiment, there is provided heat exchanger including: a case comprising a plurality of chambers, each of the plurality of chambers having a chamber entry opening to the outside; and a plurality of heat exchange tubes accommodated in the each of the plurality of chambers, where each heat exchange tube includes: an inlet portion; an outlet portion; and an intermediate portion connected between the inlet portion and the outlet portion, wherein each heat exchange tube of one of the plurality of chambers is arranged as a mirror image from corresponding heat exchange tube of an adjacent chamber of the one of the plurality of chambers with respect to a wall disposed between the one and the adjacent chambers. 
     The plurality of chambers may extend in a parallel direction from one another. 
     The inlet and outlet portions may extend in an extending direction of the plurality of chambers, wherein the inlet portion may be configured to take in an externally introduced heat transfer fluid and the outlet portion may be configured to discharge the heat transfer fluid, and wherein the intermediate portion comprises a bent portion. 
     The inlet portion of the each heat exchange tube of the one of the plurality of chambers may be arranged as a mirror image from the inlet portion of the each heat exchange tube of the adjacent chamber of the one of the plurality of chambers with respect to the wall disposed between the one and the adjacent chambers, and wherein the outlet portion of the each heat exchange tube of the one of the plurality of chambers may be arranged as a mirror image from the outlet portion of the each heat exchange tube of the adjacent chamber of the one of the plurality of chambers with respect to the wall disposed between the one and the adjacent chambers. 
     The each of the plurality of chambers may share a single wall with an adjacent chamber of the each of the plurality of chambers. 
     The case may further include fluid entrances, each of the fluid entrances configured to supply a heat exchange fluid to respective one of the plurality of chambers; and fluid exits, each of the fluid exits configured to discharge the heat exchange fluid to the outside from the respective one of the plurality of chambers, wherein the fluid entrance and the fluid exit of the respective one of the plurality of chambers are disposed within outer-most walls of the respective one of the plurality of chambers. 
     At least one of the fluid entrance and the fluid exit of the respective one of the plurality of chambers may include a quadrangular cross-section. 
     At least one of the fluid entrance and the fluid exit of the respective one of the plurality of chambers may include an extended portion extending to the adjacent chamber of one of the plurality of chambers. 
     The case may further include an oil passageway that is disposed between adjacent ones of the chambers. 
     The oil passageway may be disposed at a lower temperature region, and the lower temperature region may be a region having only an inlet portion of the each of the heat exchange tubes of one of the plurality of chambers and only an inlet portion of the each of the heat exchange tubes of the adjacent chamber of the plurality of chambers. 
     The oil passageway may extend in an extending direction of the each of the plurality of chambers, and may include an oil entrance for introducing oil; and an oil exit for discharging oil. 
     The inlet portion and the outlet portion of the each of the heat exchange tubes may be disposed from each other in a direction corresponding to an arranging direction of the plurality of chambers, and a direction in which the inlet and outlet portions of the each of the heat exchange tubes may be arranged in adjacent ones of the chambers is changed alternately. 
     The inlet portion and the outlet portion of the each of the heat exchange tubes may be disposed from each other corresponding to a direction perpendicular to an arranging direction of the plurality of chambers. 
     According to an aspect to another exemplary embodiment, there is provided a case for a heat exchanger including a plurality of chambers, each of the plurality of chambers having a chamber entry opening to the outside, wherein each chamber of the plurality of chambers shares a single wall with an adjacent chamber of the each chamber, and wherein the plurality of chambers extend in a parallel direction from one another. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a schematic perspective view illustrating coupling relationship between components of a heat exchanger according to an exemplary embodiment; 
         FIG. 2  is a schematic perspective view illustrating a coupling relationship between components of a heat exchange tube assembly in the heat exchanger of  FIG. 1  according to an exemplary embodiment; 
         FIG. 3  is a rear perspective view illustrating a state in which the components of the heat exchange tube assembly of  FIG. 2  have been assembled together according to an exemplary embodiment; 
         FIG. 4  is a cross-sectional view of the heat exchange tube assembly of  FIG. 3  according to an exemplary embodiment; 
         FIG. 5  is a cross-sectional view taken along line V-V of the heat exchanger of  FIG. 1  according to an exemplary embodiment; 
         FIG. 6  is a cross-sectional view of a heat exchanger according to another exemplary embodiment; 
         FIG. 7  is a plan view of a heat exchanger according to another exemplary embodiment; 
         FIG. 8  is a plan view of a heat exchanger according to another exemplary embodiment; 
         FIG. 9  is a plan view of a heat exchanger according to an example of the related art; 
         FIG. 10  is a cross-sectional view of the heat exchanger of  FIG. 9  according to the related art; 
         FIG. 11  is a cross-sectional view of a heat exchanger according to another example of the related art; and 
         FIG. 12  is a cross-sectional view of a heat exchanger according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A heat exchanger and a case for the heat exchanger according to exemplary embodiments\will now be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to the like elements throughout. In this regard, the exemplary embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the exemplary embodiments are merely described below, by referring to the figures, to explain aspects of the present description. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. 
       FIG. 1  is a schematic perspective view illustrating a coupling relationship between components of a heat exchanger  1  according to an exemplary embodiment. 
     Referring to  FIG. 1 , the heat exchanger  1  according to the exemplary embodiment includes a case  10  having a plurality of chambers  13  and  14 , and heat exchange tubes  21  housed in the respective chambers  13  and  14 . The case  10  accommodates a heat exchange tube assembly  20  through which a heat transfer fluid transferring heat flows in and discharges out, and includes a plurality of chamber entries  11  and  12  opening to the outside from the plurality of chambers  13  and  14 , respectively. The case  10  may be made of a metal having heat transfer characteristics. 
     The chamber entries  11  and  12  not only serve as a passage through the heat exchange tubes  21  of the heat exchange tube assembly  20  are inserted when the heat exchange tube assembly  20  is assembled into the case  10  but also support a cover  41  of the heat exchange tube assembly  20 . 
     The chambers  13  and  14  accommodate the heat exchange tubes  21  of the heat exchange tube assembly  20  and define a space in which heat exchange occurs. The chambers  13  and  14  include the chamber entries  11  and  12 , respectively, and are disposed parallel to each other so as to extend inwardly into the case  10 . 
     While the heat exchanger  1  according to the present exemplary embodiment includes the two chambers  13  and  14 , the number of chambers is not limited thereto, and may vary depending on the application of the heat exchanger  1 . 
     The case  10  also includes fluid entrances  17   a  and  18   a , which are disposed and penetrate portions of the chambers  13  and  14  to supply a heat exchange fluid to the chambers  13  and  14 , and fluid exits  17   b  and  18   b  that are disposed and penetrate other portions of the chambers  13  and  14  to discharge the heat exchange fluid to the outside. The heat exchange fluid supplied to the chambers  13  and  14  through the fluid entrances  17   a  and  18   a  makes contact with the heat exchange tubes  21  within the chambers  13  and  14  to exchange heat. 
     When the heat exchanger  1  supplies a heat exchange fluid cooled by heat exchange to each compression stage in a multi-stage compressor, each of the chambers  13  and  14  may serve to cool the heat exchange fluid that is supplied to one of the multiple compression stages. For example, if gas is supplied to one chamber  13  as a heat exchange fluid through the fluid entrance  17   a  having a quadrangular cross-section, the gas cooled by heat exchange within the chamber  13  may then be fed into one compression stage in the multi-stage compressor through the fluid exit  17   b  having a quadrangular cross-section. If gas as a heat exchange fluid is also supplied to another chamber  14  via the fluid entrance  18   a , the gas cooled by heat exchange within the chamber  14  may then be fed into another compression stage through the fluid exit  18   b.    
     The fluid entrance  17   a  and the fluid exit  17   b  having the quadrangular cross-sections may be designed to have areas equal to the fluid entrance  18   a  and the fluid exit  18   b  having circular cross-sections, respectively. 
     Since the fluid entrance  17   a  of the one chamber  13  and the fluid exit  18   b  of the other chamber  14  are disposed and penetrate within the chambers  13  and  14 , respectively, the fluid entrance  17   a  and the fluid exit  18   b  does not project out from the case  10 . Thus, this arrangement of the fluid entrance  17   a  and the fluid exit  18   b  does not increase the overall size of the case  10 , thereby achieving a compact design. 
       FIG. 2  is a schematic perspective view illustrating a coupling relationship between components of the heat exchange tube assembly  20  in the heat exchanger  1  of  FIG. 1 .  FIG. 3  is a rear perspective view illustrating a state in which the components of the heat exchange tube assembly  20  of  FIG. 2  have been assembled together according to an exemplary embodiment.  FIG. 4  is a cross-sectional view of the heat exchange tube assembly  20  of  FIG. 3  according to an exemplary embodiment. 
     Referring to  FIG. 2 , the heat exchange tube assembly  20  includes the heat exchange tubes  21  inserted into the chamber  13  of the case  10 , a support plate  42  disposed at the outside of the case  10  so as to support the heat exchange tubes  21 , and a cover  41  provided on an outer surface of the support plate  42  to define a space that allows a heat transfer fluid to flow into or out of the heat exchange tubes  21 . 
     Each of the heat exchange tubes  21  has a hollow cylindrical shape so that a heat transfer fluid can flow therein and is connected to the support plate  42 . Each of the heat exchange tubes  21  is bent into an approximate U-shape, and may be formed of a metal having heat transfer characteristics. 
     Referring to  FIGS. 2 and 4 , the cover  41  includes an entrance  41   a  into which a heat transfer fluid is introduced and an exit  42   a  from which the heat transfer fluid is discharged. The cover  41  includes a barrier rib  46  that protrude toward the support plate  42 . The support plate  42  includes a groove portion  47  for accommodating an end of the barrier rib  46 . When the cover  41  and the support plate  42  are joined by a bolt  51 , an inlet space  43  and an outlet space  44  are defined by areas between the cover  41  and the support plate  42 . 
     The heat exchange tube  21  includes an inlet portion  21   b  that extends along a direction that the chambers  13  and  14  of the case  10  extend and allows an externally introduced heat transfer fluid to pass, a curved portion  23  connected to the inlet portion  21   b  and bent toward the chamber entries  11  and  12  of the case  10 , and an outlet portion  22   b  that is connected to the curved portion  23  and extends toward the chamber entries  11  and  12  along the direction that the chambers  13  and  14  extend. Due to the above-described configuration, the inlet portion  21   b  and the outlet portion  22   b  are disposed in a direction that the chamber  13  extends inside the case  10  and are disposed parallel to each other within the chamber  13 . 
     The inlet portion  21   b  of the heat exchange tube  21  has an entrance  21   a  opening at an end thereof for introducing the heat transfer fluid therein, and the outlet portion  22   b  has an exit  22   a  opening at an end thereof for discharging the heat transfer fluid therefrom. 
     Each of the entrance  21   a  and the exit  22   a  of the heat exchange tube  21  fits into their corresponding insertion holes  48  and  49 , respectively, so that the heat exchange tube  21  is connected to the inlet space  43  and the outlet space  44 , respectively, formed by the cover  41  and the support plate  42 . 
     An upper support panel  29   a  and a lower support panel  29   b  are disposed above and below the heat exchange tube  21 , respectively. The upper support panel  29   a  and the lower support panel  29   b  are coupled to each other by a support post  28  so as to surround the heat exchange tubes  21 . A vertical panel  27  is also disposed between the upper and lower support panels  29   a  and  29   b  so that the exchange tubes  21  pass therethrough. The vertical panel  27  supports the heat exchange tube  21 . 
     A heat transfer fluid (refrigerant; not shown) introduced through the entrance  41   a  of the cover  41  flows through the inlet space  43  to the entrance  21   a  of the heat exchange tube  21 . The heat transfer fluid that has passed through the heat exchange tube  21  is drained from the exit  22   a  of the heat exchange tube  21  and flows through the outlet space  44  to the exit  42   a  of the cover  41 . 
       FIG. 5  is a cross-sectional view taken along line V-V of the heat exchanger  1  of  FIG. 1  according to an exemplary embodiment. Referring to  FIG. 5 , the adjacent chambers  13  and  14  share a common wall  15  therebetween. Although the chamber  13  has a left wall  13   a  on the left side thereof, and the chamber  14  has a right wall  14   a  on the right side thereof, only the common wall  15  is disposed between the chambers  13  and  14 . 
     As described above, the chambers  13  and  14  are formed in the case  10  to have the common wall  15  therebetween. This configuration allows heat exchange between the adjacent chambers  13  and  14  and reduces the overall size of the case  10 . 
     Referring to  FIG. 5 , heat exchange tubes  21  and  21 ′ are disposed in the adjacent chambers  13  and  14 , respectively. The heat exchange tubes  21  and  21 ′ are arranged in consideration of thermal characteristics due to heat exchange in the heat exchange tubes  21  and  21 ′. In other words, since a direction that an inlet portion  21   b  and an outlet portion  22   b  of the heat exchange tube  21  arranged in the first chamber  13  and an inlet portion  21   b ′ and an outlet portion  22   b ′ of the heat exchange tube  21 ′ arranged in the second chamber  14  is arranged in a mirror image with respect to the common wall  15 , the inlet portions  21   b  and  21   b ′ in the heat exchange tubes  21  and  21 ′ face each other in the adjacent chambers  13  and  14  as shown in  FIG. 5 . That is, the orientation of the inlet portion  21   b  and the outlet portion  22   b  of the heat exchange tube  21  in the first chamber  13  are changed alternately with respect to the inlet portion  21   b ′ and the outlet portion  22   b ′ of the heat exchange tube  21 ′. 
     More specifically, in the heat exchange tube  21  disposed in the chamber  14 , an externally introduced heat transfer fluid passes through the inlet portion  21   b  disposed in a left space  14   c  of the chamber  14  so as to transfer heat and is then discharged through the outlet portion  22   b  in a right space  14   h  thereof. 
     Since heat exchange starts at the left space  14   c  within the chamber  14  as the heat transfer fluid passes therethrough, the left space  14   c  forms a low temperature region compared to the right space  14   h  when the heat transfer fluid is a low temperature refrigerant. On the other hand, since the heat transfer fluid passes through the right space  14   h  in the chamber  14  after heat exchange occurs to some extent, the right space  14   h  forms a high temperature region. 
     Meanwhile, in the heat exchange tube  21 ′ disposed in the chamber  13 , an externally introduced heat transfer fluid passes through an inlet portion  21   b ′ disposed in a right space  13   c  of the chamber  13  so as to transfer heat and is then discharged through an outlet portion  22   b ′ in a left space  13   h  thereof. 
     Since heat exchange starts at the right space  13   c  within the chamber  13  as the heat transfer fluid passes therethrough, the right space  13   c  forms a low temperature region compared to the left space  13   h  when the heat transfer fluid is a low temperature refrigerant. On the other hand, since the heat transfer fluid passes through the left space  13   h  in the chamber  13  after heat exchange occurs to some extent, the left space  13   h  forms a high temperature region. 
     According to the above arrangement of the chambers  13  and  14  and the heat exchange tubes  21  and  21 ′, the right space  13   c  that is a low temperature region of the chamber  13  and the left space  14   c  that is a low temperature region of the chamber  14  are provided adjacent to each other having the common wall  15  in between. That is, moving from a left wall  13   a  of the first chamber  13  to a right wall  14   a  of the second chamber  14 , the case  10  has a first high temperature region, a first low temperature region, a second low temperature region and a second high temperature region. 
     Due to this structure, the chambers  13  and  14  in the case  10  of the heat exchanger  1  is configured so that the first and second low temperature regions (corresponding to the right space  13   c  and the left space  14   c ) are located densely in the central portion of the overall structure of the chamber  13  and  14 . The first and second low temperature regions of the chambers  13  and  14  are arranged to be placed adjacent to each other having the common wall  15  in between, thereby enhancing heat exchange characteristics of the heat exchanger. 
     While the heat exchange tubes  21  and  21 ′ are arranged in the chambers  13  and  14  so that the inlet portions  21   b  and  21   b ′ arranged in mirror images with each other with respect to the common wall  15  and disposed closer to the common wall  15  than the outlet portions  22   b  and  22   b ′, the exemplary embodiment is not limited thereto. That is, the outlet portions  22   b  and  22   b ′ may be arranged in a mirror image with each other and provided closer to the common wall  15  than the inlet portions  21   b  and  21   b ′ so that the high temperature regions (corresponding to the right space  14   h  and the left space  13   h ) face each other. 
     Referring to  FIGS. 1 and 5 , the fluid exit  17   b  of the first chamber  13  may extend toward the second chamber  14  adjacent thereto while the fluid entrance  18   a  of the second chamber  14  may extend toward the first chamber  13 . As shown in  FIG. 5 , the fluid exit  17   b  includes an extended portion  17   b _ 1  as part of the common wall  15  where the extended portion  17   b _ 1  curved toward the other chamber  14 . Due to the configuration of the fluid exit  17   b , it is possible to supply a sufficient flow rate of heat transfer fluid without increasing the overall size of the case  10 . Similarly, the fluid entrance  18   a  of the second chamber  14  may extend toward the first chamber  13 . Due to the configuration of the fluid exit  18   a , it is also possible to supply a sufficient flow rate of heat transfer fluid without increasing the overall size of the case  10 . 
     Referring to  FIGS. 1 and 5 , the case  10  further includes an oil passageway  19  disposed at a portion where the inlet portions  21   b  and  21   b ′ face each other, i.e., where the low temperature regions are located. 
     The oil passageway  19  extends along a direction in which the chambers  13  and  14  extend, and includes an oil entrance  19   a  for introducing oil, an oil exit  19   c  for discharging oil, and a path  19   b  for connecting the oil entrance  19   a  and the oil exit  19   c.    
     Referring to  FIG. 1 , the oil passageway  19  extends slightly obliquely along the low temperature regions between the chambers  13  and  14  according to an exemplary embodiment. However, the exemplary embodiment is not limited thereto, and the oil passageway  19  may be disposed parallel to the extending direction of the chambers  13  and  14 . 
     Due to the above arrangement of the oil passageway  19 , oil flows through between the low temperature regions of the case  10  as it passes through the oil passageway  19  of the case  10 , thereby maximizing the effect of cooling the oil. 
     For example, the oil passageway  19 , the chambers  13  and  14 , the fluid entrances  17   a  and  18   a , and the fluid exits  17   b  and  18   b  in the case  10  may be manufactured in a single casting process. In this case, it is not necessary to manufacture the oil passageway  19  separately from the case  10  and attach the oil passageway  19  thereto. Furthermore, the effect of cooling oil using the case  10  may be achieved. 
       FIG. 6  is a cross-sectional view of a heat exchanger  20  according to another exemplary embodiment. 
     Referring to  FIG. 6 , in the heat exchanger  20  according to the present exemplary embodiment, a case  210  includes three (3) chambers  113 ,  114 , 115 . The first chamber  113  shares a single wall  113   a  with the second chamber  114 , and the second chamber  114  shares a single wall  113   b  with the third chamber  115 . Thus, the overall size of the case  210  may be minimized. 
     Heat exchange tubes  120 ″,  120 ′, and  120  are disposed in the three (3) chambers  113 ,  114 , and  115 , respectively. The heat exchange tubes  120 ″ and  120 ′ are arranged so that outlet portions  122   b ″ and  122   b ′ face each other while the heat exchange tubes  120 ′ and  120  are arranged so that inlet portions  121   b ′ and  121   b  face each other. To form such a structure, a direction in which the heat exchange tubes  120 ″,  120 ′, and  120  are arranged in the three (3) chambers  113  and  114 , and  115  is changed alternately. 
     When a heat transfer fluid is a low temperature refrigerant, a region on the left side of the first chamber  113  having an inlet portion  121   b ″ therein is a low temperature region  113   c  while a region on the right side having the outlet portion  122   b ″ therein is a high temperature region  113   h . Similarly, in the second chamber  114 , a region on the right side having the inlet portion  121   b ′ therein is a low temperature region  114   c , and a region on the left side having an outlet portion  122   b ′ is a high temperature region  114   h . In addition, in the third chamber  115 , a region on the left side having the inlet portion  121   b  therein is a low temperature region  115   c , and a region on the right side having an outlet portion  122   b  therein is a high temperature region  115   h.    
     Due to the above arrangement of the heat exchange tubes  120 ″,  120 ′, and  120 , the high temperature regions  113   h  and  114   h  are oriented toward each other between the first and second adjacent chambers  113  and  114 . The low temperature regions  114   c  and  115   c  are oriented toward each other between the second and third adjacent chambers  114  and  115 . Thus, the overall heat exchange performance of the heat exchanger  20  may be significantly increased. 
     The case  210  further includes an oil passageway  119  through which oil passes. Since the oil passageway  119  extends along the low temperature regions  114   c  and  115   c , oil cooling effect may be achieved. 
       FIG. 7  is a plan view of a heat exchanger  30  according to another exemplary embodiment. 
     Referring to  FIG. 7 , in the heat exchanger  30  according to the present exemplary embodiment, a case  310  includes first through third chambers  313  through  315 . The first chamber  313  shares a single wall  313   a  having a thickness of H2 with the second chamber  314 . The second chamber  314  also shares a single wall  314   a  having a thickness of H3 with the third chamber  315 . 
     Due to the structure in which the three (3) adjacent chambers  313 ,  314 ,  315  share the walls  313   a  and  314   a  with each other, the overall size H1 of the case  310  may be minimized. Furthermore, the structure may achieve an effect of heat transfer between the three (3) adjacent chambers  313 ,  314 ,  315  through the walls  313   a  and  314   a  therebetween, thereby enhancing the overall heat exchange performance of the heat exchanger  30 . 
       FIG. 8  is a plan view of a heat exchanger  40  according to another exemplary embodiment. 
     Referring to  FIG. 8 , in the heat exchanger  40  according to the present exemplary embodiment, a case  410  includes three (3) chambers  413 ,  414 ,  415 . The first chamber  413  shares a single wall  413   a  having a thickness of T3 with the second chamber  414 . The second chamber  414  also shares a single wall  414   a  having a thickness of T2 with the third chamber  415 . 
     The three (3) chambers  413 ,  414 ,  415  include fluid entrances  417   a ,  418   a , and  419   a  for supplying a heat exchange fluid thereto, respectively. The three (3) chambers  413 ,  414 ,  415  also include fluid exits  417   b ,  418   b , and  419   b  for discharging the heat exchange fluid to the outside, respectively. An oil passageway  420  is disposed along a low temperature region between the first and second adjacent chambers  413  and  414  in such a way as to extend parallel to a direction that the first and second chambers  413  and  414  extend. 
     The fluid entrance  417   a  and the fluid exit  419   b  are disposed and penetrate within the first chamber  413  and the third chamber  415 , respectively. Thus, the fluid entrance  417   a  and the fluid exit  419   b  may supply a sufficient flow rate of heat exchange fluid without protruding out from the case  410 . 
     Due to the above-described structure, an overall length T1 of the case  410  may be minimized, thereby achieving compact designs for the case  410  and the heat exchanger  40 . 
       FIG. 9  is a plan view of a heat exchanger according to an example of the related art and  FIG. 10  is a cross-sectional view of the heat exchanger of  FIG. 9  according to the related art. 
       FIGS. 9 and 10  illustrate the heat exchanger  500  manufactured for comparison with the heat exchangers according to the exemplary embodiments. Referring to  FIGS. 9 and 10 , in a case  510  of the heat exchanger  500 , a first chamber  513  has a wall with a thickness of H5, and a second chamber  514  has a wall with a thickness of H6. The first and second chambers  513  and  514  are separated from each other by a distance of H7. 
     The second chamber  514  also has a wall with a thickness of H8, and a third chamber  515  has a wall with a thickness of H9. The second and third chambers  514  and  515  are separated from each other by a distance of H10. 
     Furthermore, since portions of the fluid entrance  517   a  of the first chamber  513  and the fluid entrance  519   a  of the third chamber  515  protrude outward from the case  510 , an overall size H4 of the case  510  may be increased. 
       FIG. 11  is a cross-sectional view of a heat exchanger according to another example of the related art. 
     Referring to  FIG. 11 , a case  610  of the heat exchanger  600  includes two chambers  613  and  614  adjacent to each other. To increase the size of a fluid entrance  614   a  of the chamber  614  on the right side by V1, a wall  613   b  of the chamber  613  on the left side has to be separated from a wall  614   b  of the chamber  614  by a large distance Q. This structure may hinder heat exchange between the chambers  613  and  614 . 
       FIG. 12  is a cross-sectional view of a heat exchanger  70  according to another exemplary embodiment. 
     Referring to  FIG. 12 , in the heat exchanger  70  according to the present exemplary embodiment, a case  710  includes three (3) chambers  713 ,  714 ,  715 . The first chamber  713  shares a single wall  713   a  with the second chamber  714 , and the second chamber  714  shares a single wall  714   b  with the third chamber  715 . Thus, the overall size of the case  710  may be minimized. 
     Heat exchange tubes  720 ″,  720 ′, and  720  are disposed in the three (3) chambers  713 ,  714 , and  715 , respectively. The heat exchange tubes  720 ″,  720 ′, and  720  are arranged so that outlet portions  722   b ″ and  722   b ′ face each other between the first and second chambers  713  and  714  and outlet portions  722   b ′ and  722   b  face each other between the second and third chambers  714  and  715 . The heat exchange tubes  720 ″,  720 ′, and  720  are also arranged so that inlet portions  721   b ″ and  721   b ′ face each other between the first and second chambers  713  and  714  and inlet portions  721   b ′ and  721   b  face each another between the second and third chambers  714  and  715 . 
     To form the above-described structure, the outlet portions  722   b ″,  722   b ′, and  722   b  are separated from the inlet portions  721   b ″,  721   b ′, and  721   b , respectively, in a vertical direction intersecting a horizontal direction in which the first through third chambers  713 ,  714 , and  715  are arranged. A direction in which the heat exchange tubes  720 ″,  720 ′, and  720  are arranged in the adjacent chambers  713  through  715  remains the same. 
     When a heat transfer fluid is a low temperature refrigerant, lower regions in the first through chambers  713  through  715  where the inlet portions  721   b ″,  721   b ′, and  721   b  face one another are low temperature regions  713   c ,  714   c , and  715   c . Upper regions where the outlet portions  722   b ″,  722   b ′, and  722   b  face one another are high temperature regions  713   h ,  714   h , and  715   h.    
     Due to the above arrangement of the heat exchange tubes  720 ″,  720 ′, and  720 , the low temperature regions  713   c ,  714   c , and  715   c  are directed toward one another, and the high temperature regions  713   h ,  714   h , and  715   h  are directed toward one another, among the first through third chambers  713 ,  714 , and  715 , thereby significantly improving overall heat exchange performance of the heat exchanger. 
     It should be understood that the exemplary embodiments described therein should be considered in a descriptive sense only and not for purposes of limitation. While one or more embodiments of the present invention have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.