Patent Publication Number: US-2020282808-A1

Title: Unidirectional Heat Exchanger

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit and priority of U.S. patent application No. 62/813,386 filed on Mar. 4, 2019, the entire disclosure of which is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a heat exchanger including a flow control assembly that provides unidirectional refrigerant flow through the heat exchanger. 
     BACKGROUND 
     This section provides background information related to the present disclosure, which is not necessarily prior art. 
     Existing heat exchangers allow refrigerant flow therethrough in both a first direction and a second direction that is opposite to the first direction. In typical heat pump systems, refrigerant has a tendency to flow to a relatively cooler area. Such refrigerant flow may disrupt the system, particularly if the system includes a cabin condenser and an exterior condenser. For example, during winter (or under other conditions when the exterior condenser is relatively cooler than the cabin condenser) refrigerant that has passed through the internal condenser may flow to an outlet of the exterior condenser and accumulate at the outlet of the exterior condenser. This refrigerant flow from the cabin condenser to the exterior condenser may disrupt refrigerant flow through the system, and may result in a reduction of refrigerant in the system. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     The present disclosure is directed to a heat exchange system. The system includes a first heat exchanger, and a second heat exchanger arranged in parallel with the first heat exchanger with respect to flow of refrigerant through the heat exchange system. A flow control assembly is at an outlet of the first heat exchanger. The flow control assembly is configured to allow refrigerant to flow out of the first heat exchanger through the flow control assembly, and restrict refrigerant that has passed through the second heat exchanger from flowing through the flow control assembly and into the first heat exchanger. 
     The present disclosure further includes a heat exchange system for a vehicle. The heat exchange system includes an external heat exchanger configured to transfer heat between refrigerant and ambient air outside the vehicle. An internal heat exchanger is configured to transfer heat between refrigerant and air inside a passenger cabin of the vehicle. The internal heat exchanger is arranged in parallel with the external heat exchanger with respect to flow of refrigerant through the heat exchange system. A flow control assembly is at an outlet of the external heat exchanger. The flow control assembly is configured to allow refrigerant to flow out of the external heat exchanger through the flow control assembly, and restrict refrigerant that has passed through the internal heat exchanger from flowing through the flow control assembly and into the external heat exchanger. The flow control assembly includes a housing defining a passageway having an inlet at the outlet of the external heat exchanger and an outlet. An expansion valve is along a refrigerant line extending from the external heat exchanger and the internal heat exchanger to an evaporator. A compressor is along a refrigerant line extending from the evaporator to the external heat exchanger and the internal heat exchanger. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of select embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  illustrates an exemplary heat pump system including an exemplary heat exchanger in accordance with the present disclosure; 
         FIG. 2A  is a cross-sectional view of a flow control assembly of the heat exchanger in accordance with the present disclosure, the flow control assembly is in an open configuration; 
         FIG. 2B  is a cross-sectional view of the flow control assembly in a closed configuration; and 
         FIG. 3  is an exploded view of components of the flow control assembly. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully with reference to the accompanying drawings. 
       FIG. 1  illustrates an exemplary heat exchange system (such as a heat pump system)  10  in accordance with the present disclosure. The heat exchange system  10  generally includes a first heat exchanger  12  and a second heat exchanger  14 . The heat exchange system  10  may be configured for use in a vehicle, with the first heat exchanger  12  configured to transfer heat between refrigerant of the system  10  and ambient air outside the vehicle. Thus the first heat exchanger  12  can be an external heat exchanger configured to be mounted at a location exposed to ambient air outside the vehicle. The second heat exchanger  14  can be an internal heat exchanger configured to transfer heat between refrigerant of the system  10  and air inside a passenger cabin of the vehicle. Thus the second heat exchanger  14  can be configured to be mounted at a location exposed to air of the passenger cabin of the vehicle. The first heat exchanger  12  and the second heat exchanger  14  may be any suitable heat exchangers, such as condensers. 
     The system  10  may further include an evaporator  16 , which is in fluid communication with the first heat exchanger  12  and the second heat exchanger  14  by way of a refrigerant line  18 . The refrigerant line  18  includes a first branch  18 A connected to the first heat exchanger  12 , and a second branch  18 B connected to the second heat exchanger  14 . Arranged along the refrigerant line  18  is an expansion valve  22 . 
     The system  10  may also include a compressor  24 . The compressor  24  is arranged along a refrigerant line  20  extending from the evaporator  16 . The refrigerant line  20  includes a first branch  20 A extending to the first heat exchanger  12 , and a second branch  20 B extending to the second heat exchanger  14 . A first valve  40  is arranged along the first branch  20 A for controlling flow of refrigerant to the first heat exchanger  12 . A second valve  42  is arranged along the second branch  20 B to control the flow of refrigerant to the second heat exchanger  14 . 
     The first heat exchanger  12  includes a main body  50  having a plurality of refrigerant tubes  52  extending back and forth across the main body  50 . Refrigerant flows into the refrigerant tubes  52  from the first branch  20 A of refrigerant line  20  through an inlet  54 . Refrigerant exits the refrigerant tubes  52  (and exits the main body  50 ) through an outlet  56  of the main body  50 . Mounted to the main body  50  at the outlet  56  is a flow control assembly  70 . Similar to the first heat exchanger  12 , the second heat exchanger  14  also includes a plurality of refrigerant tubes extending therethrough, which are connected to an inlet at the second branch  20 B and an outlet at the second branch  18 B of the refrigerant lines  20  and  18  respectively. 
     With additional reference to  FIGS. 2A, 2B, and 3 , the flow control assembly  70  of the first heat exchanger  12  will now be described in detail. The flow control assembly  70  includes a housing  72 , which is secured to the main body  50  at the outlet  56  in any suitable manner, such as by heat staking. The housing  72  defines a refrigerant passageway  74  therethrough. The refrigerant passageway  74  has an inlet  76  and an outlet  78 . The flow control assembly  70  is mounted such that the inlet  76  is at the outlet  56  of the main body  50  of the first heat exchanger  12 . 
     Seated within the passageway  74  is a movable body  80 . The movable body  80  may be made of any suitable polymeric material. The movable body  80  includes alignment members  82  extending from the moveable body  80  on a side of the movable body  80  facing the outlet  78 . The alignment members  82  may be any suitable alignment members, such as a pair of posts  82 . The movable body  80  has a maximum outer diameter that is smaller than the outlet  78  to allow the movable body  80  to be inserted through the outlet  78  into the refrigerant passageway  74 . Between the inlet  76  and the outlet  78 , at generally a mid-portion  86  of the passageway  74 , the passageway  74  widens to allow refrigerant to flow around the movable body  80 . To center the movable body  80  within the generally wider mid-portion  86  of the refrigerant passageway  74 , the alignment members  82  abut opposing portions of the passageway  74  at a relatively narrow portion  88  of the passageway  74  extending between the outlet  78  and the wider mid-portion  86  of the passageway  74 . To retain the movable body  80  within the passageway  74  (and specifically the relatively wider mid-portion  86 ), a stopper  84  is arranged between the posts  82  and the outlet  78 . After the movable body  80  is seated in the passageway  74 , the stopper  84  is inserted. The stopper  84  may be a c-clip as most clearly illustrated in  FIG. 3 , or any other suitable stopper. 
     The flow control assembly  70  further includes a seal  90 , which is seated on the movable body  80  on a side of the movable body  80  opposite to the alignment members  82 . The seal  90  may be any suitable seal, such as an annular polymeric seal. The seal  90  is arranged to abut a seal surface  92  of the passageway  74  when the movable body  80  is in a closed position (see  FIG. 2B ) to prevent refrigerant from flowing through the passageway  74  and into the first heat exchanger  12 , as explained further herein. 
     With particular reference to  FIGS. 2A and 2B , the flow control assembly  70  includes barriers  94  and/or  96 . Barrier  94  is an annular barrier extending into the passageway  74  at the inlet  76 . Barrier  96  is an annular barrier extending from the housing  72  into the outlet  56  of the first heat exchanger  12 . The barriers  94  and  96  prevent brazing flux from entering the passageway  74  when the housing  72  is brazed onto the main body  50  of the first heat exchanger  12 . 
     The movable body  80  is movable between an open position, which is illustrated in  FIG. 2A , and a closed position, which is illustrated in  FIG. 2B . The movable body  80  is moved to the open position of  FIG. 2A  by refrigerant exiting the first heat exchanger  12  when the force exerted on the movable body  80  by the refrigerant exiting the first heat exchanger  12  is greater than any force exerted on the movable body  80  by refrigerant flowing into the passageway  74  from the second heat exchanger  14  by way of the first branch  18 A. The movable body  80  is moved to the closed position of  FIG. 2B  by refrigerant entering the passageway  74  from the second heat exchanger  14  (by way of the branches  18 B and  18 A) when force exerted on the movable body  80  by the refrigerant exiting the second heat exchanger  14  is greater than force exerted on the movable body  80  by refrigerant flowing into the passageway  74  from the first heat exchanger  12 . 
     The flow control assembly  70  is particularly useful when the heat exchange system  10  is installed in a vehicle with the first heat exchanger  12  arranged as an external heat exchanger and the second heat exchanger  14  arranged as an internal heat exchanger. For example, when the external heat exchanger  12  is exposed to a relatively cooler environment as compared to the environment that the internal heat exchanger  14  is exposed to, refrigerant exiting the internal heat exchanger  14  will have a tendency to flow from the second refrigerant line branch  18 B into the first refrigerant line branch  18 A, and into the passageway  74  of the flow control assembly  70 . Under such conditions, the refrigerant will contact the movable body  80  and force the movable body  80  towards the outlet  56  of the external heat exchanger  12  such that the seal  90  seals against the seal surface  92  to prevent refrigerant from the internal heat exchanger  14  from flowing into the external heat exchanger  12 . The flow control assembly  70  thus restricts refrigerant flow through the heat exchanger  12  to only a single direction, which is from the inlet  54  to the outlet  56 . This prevents any undesirable build-up of refrigerant at the outlet  56  of the external heat exchanger  12 . One skilled in the art will appreciate that the flow control assembly  70  provides numerous additional advantages as well. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
     Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.