Patent Publication Number: US-6988538-B2

Title: Microchannel condenser assembly

Description:
FIELD OF THE INVENTION 
     This invention relates generally to condenser coils, and more particularly to condenser coils for use in retail store refrigeration systems. 
     BACKGROUND OF THE INVENTION 
     Typical retail store refrigeration systems often utilize conventional fin-and-tube condenser coils to dissipate heat from refrigerant passing through the condenser coils. Usually, in large-scale retail store refrigeration systems, a singular, oftentimes large, conventional fin-and-tube condenser coil is sized to dissipate, or reject, an amount of heat equal to the heat load of the refrigeration system. In other words, the singular fin-and-tube condenser coil is sized to dissipate the amount of heat in the refrigerant that was absorbed in other portions of the refrigeration system. 
     Fin-and-tube condenser coils, such as those utilized in many retail store refrigeration systems, often display poor efficiencies in dissipating heat from the refrigerant passing through the coils. As a result, fin-and-tube condenser coils can be rather large for the amount of heat they can dissipate from the refrigerant. Further, the larger the condenser coil becomes, the more refrigerant used in the refrigeration system, thus effectively increasing potential damage to the environment by an accidental atmospheric release. 
     Usually, in large-scale retail store refrigeration systems, the single fin-and-tube condenser coil is positioned outside the retail store, such as on a rooftop, to allow heat transfer between the fin-and-tube condenser coil and the outside environment (i.e., to allow the heat in the refrigerant to dissipate into the outside environment). Further, a mechanical draft may be provided by a fan, for example, to air-cool the fin-and-tube condenser coil. 
     Another form of heat exchangers is the microchannel coil. Currently, the only major application of microchannel coils is in the automotive industry. In an example automotive application, microchannel coils may be used as a condenser and/or an evaporator in the air conditioning system of an automobile. A microchannel condenser coil, for example, in an automotive air conditioning system is typically located toward the front of the engine compartment, where space to mount the condenser coil is limited. Therefore, the microchannel condenser coil, which is much smaller than a conventional fin-and-tube condenser coil that would otherwise be used in the automotive air conditioning system, is a suitable fit for use in an automobile. Prior to the present invention, the microchannel condenser coil has not been used in retail store refrigeration systems, in part, because of the high costs and difficulty that would be associated with manufacturing a microchannel condenser coil large enough to accommodate the heat load of the refrigeration system. 
     SUMMARY OF THE INVENTION 
     The present invention provides, in one aspect, a condenser assembly adapted to condense a refrigerant for use in a retail store refrigeration system. The condenser assembly includes at least one microchannel condenser coil including an inlet manifold and an outlet manifold. The inlet manifold has an inlet port for receiving the refrigerant, and the outlet manifold has an outlet port for discharging the refrigerant. The condenser assembly also includes a frame supporting the condenser coil. 
     The present invention provides, in another aspect, a condenser assembly adapted to condense a refrigerant for use in a retail store refrigeration system. The condenser assembly includes a first microchannel condenser coil configured such that the refrigerant makes at least one pass therethrough, and a second microchannel condenser coil fluidly connected with the first microchannel condenser coil. The second microchannel condenser coil is configured such that the refrigerant makes at least one pass through the second microchannel condenser coil after making at least one pass through the first microchannel condenser coil. The condenser assembly also includes a frame supporting the first and second microchannel condenser coils. 
     The present invention provides, in yet another aspect, a condenser assembly adapted to condense a refrigerant for use in a retail store refrigeration system. The condenser assembly includes a first microchannel condenser coil configured such that the refrigerant makes at least one pass therethrough, and a second microchannel condenser coil configured such that the refrigerant makes at least one pass therethrough. The condenser assembly also includes an inlet header fluidly connected with the first and second microchannel condenser coils. The inlet header is configured to deliver the refrigerant to the first and second microchannel condenser coils The condenser assembly further includes an outlet header fluidly connected with the first and second microchannel condenser coils. The outlet header is configured to receive refrigerant from the first and second microchannel condenser coils. The first and second microchannel condenser coils are connected to receive and deliver refrigerant in a parallel relationship between the inlet and outlet headers. The condenser assembly also includes a frame supporting the first and second microchannel condenser coils. 
     The present invention provides, in a further aspect, a method of assembling a condenser assembly adapted to condense a refrigerant for use in a retail store refrigeration system. The method includes providing a first microchannel condenser coil configured such that the refrigerant makes at least one pass therethrough, fluidly connecting the first microchannel condenser coil to a second microchannel condenser coil configured such that the refrigerant makes at least one pass through the second microchannel condenser after making at least one pass through the first microchannel condenser coil, and supporting the first and second microchannel condenser coils with a frame. 
     The present invention provides, in another aspect, a method of assembling a condenser assembly adapted to condense a refrigerant for use in a retail store refrigeration system. The method includes providing a first microchannel condenser coil configured such that the refrigerant makes at least one pass therethrough and a second microchannel condenser coil configured such that the refrigerant makes at least one pass therethrough. The method also includes fluidly connecting an inlet header to the first and second microchannel condenser coils. The inlet header is configured to deliver the refrigerant to the first and second microchannel condenser coils. The method further includes fluidly connecting an outlet header to the first and second microchannel condenser coils. The outlet header is configured to receive the refrigerant from the first and second microchannel condenser coils. The first and second microchannel condenser coils are connected to receive and deliver refrigerant in a parallel relationship between the inlet and outlet headers. Also, the method includes supporting the first and second microchannel condenser coils with a frame. 
     Other features and aspects of the present invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, wherein like reference numerals indicate like parts: 
         FIG. 1  is a perspective view of a first construction of a condenser assembly of the present invention. 
         FIG. 2  is an enlarged perspective view of a first microchannel condenser coil of the condenser assembly of  FIG. 1 . 
         FIG. 3   a  is a partial section view of the first microchannel condenser coil of  FIG. 2 , exposing multiple microchannels. 
         FIG. 3   b  is a broken view of the first microchannel condenser coil of  FIG. 2 . 
         FIG. 4  is a perspective view of a second construction of a condenser assembly of the present invention. 
         FIG. 5  is a perspective view of a condensing unit including the condenser assembly of  FIG. 1  and a compressor. 
         FIG. 6   a  is a perspective view of a second microchannel condenser coil that may be utilized in a condenser assembly of the present invention. 
         FIG. 6   b  is a perspective view of a third microchannel condenser coil that may be utilized in a condenser assembly of the present invention. 
         FIG. 7   a  is a schematic view of multiple microchannel condenser coils arranged as a multiple row assembly, illustrating the multiple coils in a series arrangement. 
         FIG. 7   b  is a schematic view of multiple microchannel condenser coils arranged as a multiple row assembly, illustrating the multiple coils in a parallel arrangement. 
         FIG. 8   a  is a schematic view of multiple microchannel condenser coils arranged in a single row assembly, illustrating the multiple coils in a series arrangement. 
         FIG. 8   b  is a schematic view of multiple microchannel condenser coils arranged in a single row assembly, illustrating the multiple coils in a parallel arrangement. 
         FIG. 9   a  is a schematic view of multiple coil assemblies in a series configuration with an inlet header and an outlet header. 
         FIG. 9   b  is a schematic view of multiple coil assemblies in a parallel configuration with an inlet header and an outlet header. 
         FIG. 10  is a perspective view of a third construction of a condenser assembly of the present invention. 
         FIG. 11  is a perspective view of a fourth construction of a condenser assembly of the present invention. 
         FIG. 12  is a perspective view of a fifth construction of a condenser assembly of the present invention. 
     
    
    
     Before any features of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limited. 
     DETAILED DESCRIPTION 
     With reference to  FIG. 1 , a first configuration of a condenser assembly  10  is shown. The condenser assembly  10  may be used in a large-scale retail store refrigeration system, such as that found in many large grocery stores or supermarkets. In such a refrigeration system, the condenser assembly  10  may be positioned outside the retail store, such as on the rooftop of the store, to allow heat transfer from the condenser assembly  10  to the outside environment. The role of the condenser assembly  10  in the refrigeration system is to receive compressed, gaseous refrigerant from one or more compressors (not shown), condense the gaseous refrigerant back into its liquid form, and discharge the compressed, liquid refrigerant to one or more evaporators (not shown) located inside the store. The liquid refrigerant is evaporated when it is passed through the evaporators, and the gaseous refrigerant is drawn into the one or more compressors for re-processing into the refrigeration system. 
     “Refrigerant-22,” or “R-22,” in addition to anyhydrous ammonia, for example, may be used in such a refrigeration system to provide sufficient cooling to the refrigeration system. If R-22 is used as the refrigerant of choice, the components of the refrigeration system in contact with the R-22 may be made from copper, aluminum, or steel, among other materials. However, as understood by those skilled in the art, if anyhydrous ammonia is used as the refrigerant of choice, copper components of the refrigeration system in contact with the anyhydrous ammonia may corrode. Alternatively, other refrigerants (including both two-phase and single-phase refrigerants or coolants) may be used with the condenser assembly  10 . 
     In addition to retail store refrigeration systems, the condenser assembly  10  may also be used in various process industries, where the condenser assembly  10  may be a portion of a fluid cooling system using a single-phase coolant (e.g., glycol). In such an application, the role of the condenser assembly  10  the fluid cooling system is to receive heated liquid coolant from one or more heat sources (e.g., a pump or an engine, not shown), cool the heated liquid, and discharge the cooled liquid coolant to the one or more heat sources. The cooled liquid coolant is again heated when it is put in thermal contact with the one or more heat sources, and the heated gaseous coolant is routed by a pump or compressors for re-processing into the fluid cooling system. 
     In the illustrated construction of  FIG. 1 , the condenser assembly  10  includes two microchannel condenser coils  14   a ,  14   b  being supported by a frame  18 . The frame  18  may be a freestanding structure as shown in  FIG. 1 . However, the frame  18  may comprise any number of different designs other than that shown in  FIG. 1 . As such, the illustrated frame  18  of  FIG. 1  is intended for illustrative purposes only. 
     As shown in  FIGS. 3   a – 3   b , each microchannel condenser coil  14   a ,  14   b  includes an inlet manifold  22   a ,  22   b  and an outlet manifold  26   a ,  26   b  fluidly connected by a plurality of flat tubes  30 . The inlet manifold  22   a ,  22   b  includes an inlet port  34   a ,  34   b  for receiving refrigerant, and the outlet manifold  26   a ,  26   b  includes an outlet port  38   a ,  38   b  for discharging the refrigerant. One or more baffles (not shown) may be placed in the inlet manifold  22   a ,  22   b  and/or the outlet manifold  26   a ,  26   b  to cause the refrigerant to make multiple passes through the flat tubes  30  for enhanced cooling of the refrigerant. 
     The flat tubes  30  may be formed to include multiple internal passageways, or microchannels  42 , that are much smaller in size than the internal passageway of the coil in a conventional fin-and-tube condenser coil. The microchannels  42  allow for more efficient heat transfer between the airflow passing over the flat tubes  30  and the refrigerant carried within the microchannels  42 , compared to the airflow passing over the coil of the conventional fin-and-tube condenser coil. In the illustrated construction, the microchannels  42  each are configured with a rectangular cross-section, although other constructions of the flat tubes  30  may have passageways of other cross-sections. The flat tubes  30  are separated into about 10 to 15 microchannels  42 , with each microchannel  42  being about 1.5 mm in height and about 1.5 mm in width, compared to a diameter of about 9.5 mm (⅜″) to 12.7 mm (½″) for the internal passageway of a coil in a conventional fin-and-tube condenser coil. However, in other constructions of the flat tubes  30 , the microchannels  42  may be as small as 0.5 mm by 0.5 mm, or as large as 4 mm by 4 mm. 
     The flat tubes  30  may also be made from extruded aluminum to enhance the heat transfer capabilities of the flat tubes  30 . In the illustrated construction, the flat tubes  30  are about 22 mm wide. However, in other constructions, the flat tubes  30  may be as wide as 26 mm, or as narrow as 18 mm. Further, the spacing between adjacent flat tubes  30  may be about 9.5 mm. However, in other constructions, the spacing between adjacent flat tubes  30  may be as much as 16 mm, or as little as 3 mm. 
     As shown in  FIG. 3   b , each microchannel condenser coil  14   a ,  14   b  includes a plurality of fins  46  coupled to and positioned along the flat tubes  30 . The fins  46  are generally arranged in a zig-zag pattern between adjacent flat tubes  30 . In the illustrated construction, the fin density mesured along the length of the flat tubes  30  is between  12  and  24  fins per inch. However, in other constructions of the microchannel condenser coils  14   a ,  14   b , the fin density may be slightly less than 12 fins per inch or more than 24 fins per inch. Generally, the fins  46  aid in the heat transfer between the airflow passing through the microchannel condenser coils  14   a ,  14   b  and the refrigerant carried by the microchannels. The fins  46  may also include a plurality of louvers formed therein to provide additional heat transfer area. The increased efficiency of the microchannel condenser coils  14   a ,  14   b  is due in part to such a high fin density, compared to the fin density of 2 to 4 fins per inch of a conventional fin-and-tube condenser coil. 
     The increased efficiency of the microchannel condenser coils  14   a ,  14   b , compared to a conventional fin-and-tube condenser coil, allows the microchannel condenser coils  14   a ,  14   b  to be physically much smaller than the fin-and-tube condenser coil. As a result, the microchannel condenser coils  14   a ,  14   b  are not nearly as tall, and are not nearly as wide as a conventional fin-and-tube condenser coil. 
     The microchannel condenser coils  14   a ,  14   b  are attractive for use with large-scale refrigeration systems for these and other reasons. Since the microchannel condenser coils  14   a ,  14   b  are much smaller than conventional fin-and-tube condenser coils, the microchannel condenser coils  14   a ,  14   b  may occupy less space on the rooftops of the retail stores in which they are installed. As a result, the microchannel condenser coils  14   a ,  14   b  are more aesthetically appealing from an outside perspective of the store. 
     Since the microchannel condenser coils  14   a ,  14   b  are much smaller than conventional fin-and-tube condenser coils, the microchannel condenser coils  14   a ,  14   b  may also contain less refrigerant compared to the conventional fin-and-tube condenser coils. Further, less refrigerant may be required to be contained within the entire refrigeration system, therefore effectively decreasing potential damage to the environment by an accidental atmospheric release. Also, as a result of being able to decrease the amount of refrigerant in the refrigeration system, the retail stores may see an energy savings, since the compressor(s) may expend less energy to compress the decreased amount of refrigerant in the refrigeration system. 
     The condenser assembly  10  also includes fans  50  coupled to the microchannel condenser coils  14   a ,  14   b  to provide an airflow through the coils  14   a ,  14   b . As shown in  FIGS. 1 and 2 , each microchannel condenser coil  14   a ,  14   b  includes two fans  50  mounted thereon. Alternatively, centrifugal blowers (not shown) may be used in place of the fans  50  or in combination with the fans  50 . The fans  50  are supported in a fan shroud  54 , which guides the airflow generated by the fans  50  through the microchannel condenser coils  14   a ,  14   b , and helps distribute the airflow amongst the face of each condenser coil  14   a ,  14   b . In a preferred construction of the condenser assembly  10 , the fans  50  may be “low-noise” fans, like the SWEPTWING™ fans available from Revcor, Inc. of Carpentersville, Ill. to help decrease noise emissions from the condenser assembly  10 . In other constructions of the condenser assembly  10 , more or less than two fans  50  may be used for each condenser coil  14   a ,  14   b  to generate the airflow through the condenser coil  14   a ,  14   b . Also, the fans  50  and/or the shroud  54  may comprise any number of designs different than that shown in  FIGS. 1–2 . 
       FIG. 2  illustrates the shroud  54  supporting an electric motor  58  for driving one of the fans  50 . The electric motor  58  may be configured to operate using either an AC or DC power source. Further, the electric motor  58  may be electrically connected to a controller (not shown) that selectively activates the electric motor  58  to drive the fan  50  depending on any number of conditions monitored by the controller. For example, the fans  50  may be cycled on and off to either increase or decrease the heat transfer capability of the condenser coils  14   a ,  14   b . In one manner of operating the fans  50 , the fans  50  may be turned off during the nighttime, when the ambient temperature around the condenser assembly  10  is typically less than during the daytime. In another manner of operating the fans  50 , the controller may receive a signal from a pressure sensor that is in communication with one or both of the condenser coils  14   a ,  14   b  that is proportional to the pressure in the coils  14   a ,  14   b . A measured pressure greater than some pre-determined threshold pressure may trigger the controller to activate the electric motors  58  to drive the fans  50  to provide additional heat transfer capability to the coils  14   a ,  14   b . Likewise, a measured pressure less than some pre-determined threshold pressure may trigger the controller to deactivate the electric motors  58  to stop the fans  50 . 
       FIG. 1  illustrates two microchannel condenser coils  14   a ,  14   b  fluidly connected with the refrigeration system in a series arrangement. The inlet port  34   a  of a first microchannel condenser coil  14   a  is shown coupled to an inlet header  59 , whereby compressed, gaseous refrigerant is pumped to the first microchannel condenser coil  14   a  via the inlet header  59 . In the illustrated construction, the inlet header  59  is coupled to the inlet port  34   a  by a brazing or welding process. Such a brazing or welding process provides a substantially fluid-tight connection between the inlet header  59  and the inlet port  34   a . However, other constructions of the condenser assembly  10  may utilize some sort of fluid-tight releasable couplings to allow serviceability of the coils  14   a ,  14   b.    
     The outlet port  38   a  of the first microchannel condenser coil  14   a  is shown coupled to an inlet port  34   b  of a second microchannel condenser coil  14   b  via a connecting conduit  60 . In the illustrated construction, the outlet port  38   a  of the first microchannel condenser coil  14   a  is coupled to the connecting conduit  60  by a brazing or welding process, and the inlet port  34   b  of the second microchannel condenser coil  14   b  is also coupled the connecting conduit  60  by a brazing or welding process. As previously stated, such a brazing or welding process provides a substantially fluid-tight connection between the outlet port  38   a  of the first microchannel condenser coil  14   a  and the inlet port  34   b  of the second microchannel condenser coil  14   b . However, other constructions of the condenser assembly  10  may utilize some sort of permanent or releasable fluid-tight couplings. 
     The outlet port  38   b  of the second microchannel condenser coil  14   b  is shown coupled to an outlet header  61 , whereby compressed, substantially liquefied refrigerant is discharged from the second microchannel condenser coil  14   b  to the outlet header  61  for transporting the liquid refrigerant to a receiver (not shown) or other component in the refrigeration system. Further, in the illustrated construction, the outlet port  38   b  of the second microchannel condenser coil  14   b  is coupled to the outlet header  61  by a brazing or welding process to provide a substantially fluid-tight connection between the outlet port  38   b  of the second microchannel condenser coil  14   b  and the outlet header  61 . However, other constructions of the condenser assembly  10  may utilize some sort of permanent or releasable fluid-tight couplings. 
     During operation of the refrigeration system utilizing the condenser assembly  10  of  FIG. 1 , the compressed, gaseous refrigerant is pumped into the first microchannel condenser coil  14   a , where the heat transfer between the airflow passing through the condenser coil  14   a  and the refrigerant causes the gaseous refrigerant to at least partially condense as the refrigerant passes through the flat tubes  30 . If baffles are not placed in either of the inlet or outlet manifolds  22   a ,  26   a  of the first microchannel condenser coil  14   a , the refrigerant will make one pass from the inlet manifold  22   a  to the outlet manifold  26   a  before being discharged from the first microchannel condenser coil  14   a . Further, the fans  50  may be activated to provide and/or enhance the airflow through the first microchannel condenser coil  14   a  to further enhance cooling of the refrigerant. 
     Since the condenser coils  14   a ,  14   b  are connected in a series arrangement, the refrigerant is passed from the first microchannel condenser coil  14   a  to the second microchannel condenser coil  14   b . If only a portion of the compressed, gaseous refrigerant is condensed in the first microchannel condenser coil  14   a , then the remaining portion is condensed in the second microchannel condenser coil  14   b . Like the first microchannel condenser coil  14   a , if baffles are not placed in either of the inlet or outlet manifolds  22   b ,  26   b  of the second microchannel condenser coil  14   b , the refrigerant will make one pass from the inlet manifold  22   b  to the outlet manifold  26   b  before being discharged from the second microchannel condenser coil  14   b . Further, the fans  50  may be activated to provide and/or enhance the airflow through the second microchannel condenser coil  14   b  to further enhance cooling of the refrigerant. 
       FIG. 4  illustrates a condenser assembly  62  having two microchannel condenser coils  64   a ,  64   b  fluidly connected with the refrigeration system in a parallel arrangement. The frame  18  illustrated in  FIG. 4  is substantially the same as that shown in  FIG. 1 , the particular design of which is for illustrative purposes only and will not be further discussed. The fans  50  and the fan shrouds  54  are also substantially the same as that shown in  FIG. 1 , and will not be further discussed. Inlet ports  66   a ,  66   b  of the first and second microchannel condenser coils  64   a ,  64   b  are shown extending from inlet manifolds  70   a ,  70   b  and coupled to an inlet header  74 , whereby compressed, gaseous refrigerant is pumped to the first and second microchannel condenser coils  64   a ,  64   b  via the inlet header  74 . In the illustrated construction, the inlet header  74  is coupled to the inlet ports  66   a ,  66   b  of the first and second microchannel condenser coils  64   a ,  64   b  by a brazing or welding process to provide a substantially fluid-tight connection between the inlet header  74  and the inlet ports  66   a ,  66   b . However, other constructions of the condenser assembly  62  may utilize some sort of permanent or releasable fluid-tight couplings. 
     In addition, “orifice buttoning” may be used in the condenser assembly  62  to facilitate a substantially equal distribution of refrigerant to the coils  64   a ,  64   b  along the inlet header  74 . This may be accomplished by varying the flow space through the inlet ports  66   a ,  66   b  of the coils  64   a ,  64   b . In the illustrated construction of  FIG. 4 , coil  64   b  is located downstream of coil  64   a . Furthermore, to maintain a substantially similar flow rate of refrigerant through both of the coils  64   a ,  64   b , the inlet port  66   a  of coil  64   a  may be smaller than the inlet port  66   b  of coil  64   b  to accommodate for the pressure drop between the coils  64   a ,  64   b . However, in other constructions of the condenser assembly  62 , other restricting devices (not shown) may be positioned in the inlet ports  66   a ,  66   b  to provide a varying flow space rather than varying the size of the inlet ports  66   a ,  66   b.    
     Outlet ports  78   a ,  78   b  of the first and second microchannel condenser coils  64   a ,  64   b  are shown extending from outlet manifolds  82   a ,  82   b  coupled to an outlet header  86 , whereby compressed, liquid refrigerant is discharged from the first and second microchannel condenser coils  64   a ,  64   b  via the outlet header  86 . In the illustrated construction, the outlet header  86  is coupled to the outlet ports  78   a ,  78   b  of the first and second microchannel condenser coils  64   a ,  64   b  by a brazing or welding process to provide a substantially fluid-tight connection between the outlet header  86  and the outlet ports  78   a ,  78   b . However, other constructions of the condenser assembly  62  may utilize some sort of permanent or releasable fluid-tight couplings. 
     In some constructions of the condenser assembly  62 , the outlet header  86  may be configured to be used as a receiver for the liquid refrigerant condensed by the microchannel condenser coils  64   a ,  64   b  (see  FIG. 10 ). The receiver is typically sized to be able to hold all of the refrigerant in the system in a condensed form. One or more liquid refrigerant lines may therefore fluidly connect the receiver and the one or more evaporators in the refrigeration system. By configuring the outlet header  86  to also act as the liquid refrigerant receiver, a dedicated separate receiver tank (not shown) is not required in the refrigeration system. This allows a sizable component, in addition to the piping associated therewith, to be eliminated from the refrigeration system. Additional benefits such as those outlined above may be realized by reducing the amount of refrigerant in the refrigeration system. 
     Also, in the illustrated construction, the inlet ports  66   a ,  66   b  extend substantially transversely from the inlet manifolds  70   a ,  70   b , and the outlet ports  78   a ,  78   b  extend substantially transversely from the outlet manifolds  82   a ,  82   b  to fluidly connect with the inlet and outlet headers  74 ,  86 . However, in other constructions of the condenser assembly  62 , the inlet ports  66   a ,  66   b  and the outlet ports  78   a ,  78   b  may extend from the respective inlet manifolds  70   a ,  70   b  and the outlet manifolds  82   a ,  82   b  as shown in  FIG. 1 , and utilize additional intermediate piping to fluidly connect the inlet ports  66   a ,  66   b  with the inlet header  74  and the outlet ports  78   a ,  78   b  with the outlet header  86 . 
     During operation of the refrigeration system utilizing the condenser assembly  62  of  FIG. 4 , the compressed, gaseous refrigerant is pumped through the inlet header  74 , where the some of the gaseous refrigerant enters the first microchannel condenser coil  64   a  and the remaining gaseous refrigerant enters the second microchannel condenser coil  64   b . Heat transfer between the airflow passing through the condenser coils  64   a ,  64   b  and the refrigerant causes the gaseous refrigerant to condense as the refrigerant passes through the flat tubes  30 . If baffles are not placed in either of the inlet manifold  70   a  or the outlet manifold  82   a  of the first microchannel condenser coil  64   a , the refrigerant will make one pass from the inlet manifold  70   a  to the outlet manifold  82   a  before being discharged from the first microchannel condenser coil  64   a  to the outlet header  86 . Further, the fans  50  may be activated to provide and/or enhance the airflow through the first microchannel condenser coil  64   a  to further enhance cooling of the refrigerant. 
     Since the condenser coils  64   a ,  64   b  are connected with the refrigeration system in a parallel arrangement, and if baffles are not placed in either of the inlet manifold  70   b  or the outlet manifold  82   b  of the second microchannel condenser coil  64   b , the refrigerant will make one pass from the inlet manifold  70   b  to the outlet manifold  82   b  before being discharged from the second microchannel condenser coil  64   b  to the outlet header  86 , where the liquid refrigerant rejoins the liquid refrigerant discharged by the first microchannel condenser coil  64   a . Further, the fans  50  may be activated to provide and/or enhance the airflow through the second microchannel condenser coil  64   b  to further enhance cooling of the refrigerant. 
     Each microchannel condenser coil  64   a ,  64   b  may also include multiple inlet and outlet ports (not shown), corresponding with multiple baffles (not shown) located within the inlet manifolds  70   a ,  70   b  and/or the outlet manifolds  82   a ,  82   b  to provide multiple cooling circuits throughout each microchannel condenser coil  64   a ,  64   b.    
     The condenser assembly  10  or  62  may also include a compressor  90  coupled thereto to yield a condenser unit  94  (see  FIG. 5 ). The compressor  90  may be coupled to the frame  18  of the condenser assembly  10  or  62  by any of a number of conventional methods, and may be fluidly connected with the microchannel condenser coils  14   a ,  14   b ,  64   a ,  64   b  to provide the compressed, gaseous refrigerant to the coils  14   a ,  14   b ,  64   a ,  64   b . Conventionally, the compressor is located in a machine room separate from the retail area of the retail store. The compressor in the machine room is typically remotely located from the rest of the components in the refrigeration system, including the evaporators, which are typically located within refrigerated merchandisers (not shown) in the retail area of the store, and the condensers, which are typically located on the rooftop of the retail store. By placing the compressor  90  with the condenser assembly  10  or  62 , the amount of piping and conduit required to fluidly connect the compressor  90  with the microchannel condenser coils  14   a ,  14   b ,  64   a ,  64   b  may be decreased. Subsequently, the amount of refrigerant that is carried in the system may also be decreased. 
     The microchannel condenser coils  14   a ,  14   b ,  64   a ,  64   b  allow for a unique method of assembling the condenser assemblies  10 ,  62 . As previously stated, a single, large conventional fin-and-tube condenser coil is typically provided in a retail store refrigeration system to condense all of the refrigerant in the refrigeration system. This conventional fin-and-tube condenser coil must be appropriately sized to accommodate the heat load of the refrigeration system. In other words, the conventional fin-and-tube condenser coil must be large enough to dissipate the heat in the gaseous refrigerant for the entire system. Such a condenser coil must often be custom manufactured to the size required by the refrigeration system. Further, the frame and fan shrouds may also require custom manufacturing to match up with the custom manufactured conventional fin and tube condenser coil. This may drive up the costs associated with manufacturing a condenser assembly utilizing a conventional fin-and-tube condenser coil. 
     The microchannel condenser coils  14   a ,  14   b ,  64   a ,  64   b  are manufactured in standard sizes, which allows the manufacturer of the condenser assembly  10  or  62  to utilize their expertise to calculate the total heat load of a particular refrigeration system and determine how many standard-sized microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b  will be required to satisfy the total heat load of the refrigeration system. After determining how many standard-sized microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b  will be required, the manufacturer may utilize their capabilities to put together the condenser assembly  10  or  62 . Fluid connections may be made by brazing or welding processes, or releasable couplings may be used to allow serviceability of the coils  14   a ,  14   b  or  64   a ,  64   b . Further, the fans  50  and the fan shrouds  54  may be manufactured or purchased by the condenser assembly manufacturer in standard sizes to match up with the standard-sized microchannel condenser coils  14   a ,  14   b ,  64   a ,  64   b . Also, the frame  18  may be either custom made to support multiple connected microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b , or the frame  18  may be standard-sized to support a single or dual microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b , for example. This method of assembling the condenser assemblies  10 ,  62  may allow the manufacturer to streamline their operation, which in turn may result in decreased costs for the manufacturer. 
     Although only two microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b  are shown in the illustrated constructions of  FIGS. 1 and 4 , more or less than two microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b  may be included in the condenser assemblies  10  or  62  to satisfy the total heat load of the refrigeration system in which the microchannel condenser coils  14   a ,  14   b  or  64   a ,  64   b  will be used. 
     With reference to  FIGS. 6   a  and  6   b , other condenser coils may be utilized in the condenser assemblies  10 ,  62 .  FIG. 6   a  illustrates a microchannel condenser coil  98  substantially similar to the coils  14   a ,  14   b ,  64   a ,  64   b  with the exception that the coil  98  includes multiple inlet ports  102  and outlet ports  106 . This style of microchannel condenser coil  98  may provide a better distribution of vaporized refrigerant to an inlet manifold  110  of the coil  98 , in addition to a better distribution of liquid refrigerant from an outlet manifold  114  of the coil  98 . 
       FIG. 6   b  illustrates another microchannel condenser coil  118  substantially similar to the coils  14   a ,  14   b ,  64   a ,  64   b ,  98  with the exception that the coil  118  is divided into two separate and distinct fluid circuits by a baffle  122  positioned in an inlet manifold  126  of the coil  118  and another baffle  130  positioned in an outlet manifold  134  of the coil  118 . This style of microchannel condenser coil  118  may allow refrigerant from multiple refrigeration circuits (corresponding with multiple refrigeration display cases) to be passed through the coil  118 . As a result, benefits such as a reduction in the number of separate and dedicated condenser coils for each refrigeration circuit may be achieved by using the coil  118  of  FIG. 6   b . Subsequently, the amount of refrigerant that is carried in each refrigeration circuit may also be reduced. 
     With reference to  FIGS. 7   a – 8   b , any of the microchannel condenser coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be grouped together in either single-row assemblies or multiple-row assemblies.  FIGS. 7   a  and  7   b  illustrate coils being grouped in multiple-row assemblies  138 ,  142 , respectively. Specifically,  FIGS. 7   a  and  7   b  illustrate coils being grouped in three-row assemblies  138 ,  142 . In the three-row assemblies  138 ,  142  of  FIGS. 7   a  and  7   b , the coils are stacked one on top of another such that airflow is directed through all of the coils. Although three coils are shown in the multiple-row assemblies  138 ,  142  of  FIGS. 7   a  and  7   b , more or less than three coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be used depending on the total heat load of a particular refrigeration system in which the assemblies  138 ,  142  are used. In addition, although  FIGS. 7   a  and  7   b  generally illustrate the coils  14   a ,  14   b , it should be known that any of the coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be used in forming the assemblies  138 ,  142 . 
     With particular reference to  FIG. 7   a , the three coils in the assembly  138  are shown in a fluid series connection, whereby refrigerant is passed through the three coils one after another. However, with particular reference to  FIG. 7   b , the three coils in the assembly  142  are shown in a fluid parallel connection, whereby refrigerant is passed through the coils independently of one another. In constructing the condenser assemblies  10 ,  62 , it is up to the manufacturer to determine if multiple-row assemblies  138 ,  142  will be used. Furthermore, if multiple-row assemblies  138 ,  142  are to be used, it is up to the manufacturer to determine whether to use an assembly  138  having coils grouped in a fluid series connection, or an assembly  142  having coils grouped in a fluid parallel connection. 
       FIGS. 8   a  and  8   b  illustrate coils being grouped in single-row assemblies  146 ,  150 . Specifically,  FIGS. 8   a  and  8   b  illustrate the coils being grouped in a single-row assembly  146  of three coils. In the single-row assemblies  146 ,  150  of  FIGS. 8   a  and  8   b , the coils are unfolded, or spread out such that airflow passing through one of the coils is not directed through another of the three coils. Although three coils are shown in the single-row assemblies  146 ,  150  of  FIGS. 8   a  and  8   b , more or less than three coils may be used depending on the total heat load of the particular refrigeration system in which the assemblies  146 ,  150  are used. In addition, although  FIGS. 8   a  and  8   b  generally illustrate the coils  14   a ,  14   b , it should be known that any of the coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be used in forming the assemblies  146 ,  150 . 
     With particular reference to  FIG. 8   a , the three coils in the assembly  146  are shown in a fluid series connection, whereby refrigerant is passed through the three coils one after another. However, with particular reference to  FIG. 8   b , the three coils in the assembly  150  are shown in a fluid parallel connection, whereby refrigerant is passed through the coils independently of one another. In constructing the condenser assemblies  10 ,  62 , it is up to the manufacturer to determine if single-row assemblies  146 ,  150  will be used. Furthermore, if single-row assemblies  146 ,  150  are to be used, it is up to the manufacturer to determine whether to use an assembly  146  having coils grouped in a fluid series connection, or an assembly  150  having coils grouped in a fluid parallel connection. 
     With reference to  FIGS. 9   a – 9   b , one or more assemblies  138 ,  142 ,  146 , or  150  may be grouped into a series configuration  154  or a parallel configuration  158  with an inlet header  162  and an outlet header  166 . As shown in  FIG. 9   a , a three-row assembly  138  and a single row assembly  146  are grouped into a fluid series configuration  154  between the inlet header  162  and the outlet header  166 . Although the three-row assembly  138  and single-row assembly  146  are shown in the series configuration  154  of  FIG. 9   a , any combination of multiple-row assemblies  138  or  142  and single-row assemblies  146  or  150  may be used depending on the determination of the manufacturer. In addition, more or less than two assemblies  138 ,  142 ,  146 , or  150  may be used in the series configuration  154  depending on the total heat load of the particular refrigeration system in which the series configuration  154  is used. In addition, although  FIG. 9   a  generally illustrates the coils  14   a ,  14   b , it should be known that any of the coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be used in forming the assemblies  138 ,  142 ,  146 , or  150  that comprise either the series configuration  154  or the parallel configuration  158 . 
     As shown in  FIG. 9   b , a three-row assembly  138  and a single row assembly  146  are grouped into a fluid parallel configuration  158  between the inlet header  162  and the outlet header  166 . Although the three-row assembly  138  and the single-row assembly  146  are shown in the parallel configuration  158  of  FIG. 9   b , any combination of multiple-row assemblies  138  or  142  and single-row assemblies  146  or  150  may be used depending on the determination of the manufacturer. In addition, more or less than two assemblies  138 ,  142 ,  146 , or  150  may be used in the parallel configuration  158  depending on the total heat load of the particular refrigeration system in which the parallel configuration  158  is used. In addition, although  FIG. 9   a  generally illustrates the coils  14   a ,  14   b , it should be known that any of the coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be used in forming the assemblies  138 ,  142 ,  146 , or  150  that comprise either the series configuration  154  or the parallel configuration  158 . Further, one or more baffles (not shown) may be positioned in the inlet and outlet headers  162 ,  166  between adjacent assemblies  138 ,  142 ,  146 , or  150  to divide the configuration  154  or  158  into multiple fluid circuits. 
     Using the above terminology,  FIG. 1  illustrates a single-row assembly  146  in a series configuration  154  between the inlet header  59  and the outlet header  61 , whereby the coils  14   a ,  14   b  in the single-row assembly  146  are grouped into a fluid series connection. Also, using the above terminology,  FIG. 4  illustrates a single-row assembly  150  in a parallel configuration  158  between the inlet header  74  and the outlet header  86 , whereby the coils  64   a ,  64   b  in the single-row assembly  150  are grouped into a fluid parallel connection. 
       FIG. 10  illustrates a third construction of a condenser assembly  170  including three two-row assemblies  138  in a parallel configuration  158  between an inlet header  174  and an outlet header  178 . Each two-row assembly  138  includes two microchannel condenser coils  14   a ,  14   b  grouped in a fluid series connection. Rather than being permanently connected to the inlet and outlet headers  174 ,  178 , respectively, the coils  14   a ,  14   b  may be coupled to the inlet and outlet headers  174 ,  178  by fluid-tight releasable couplings  182 . The couplings  182  are illustrated in  FIG. 10 , and may comprise any known suitable fluid-tight, quick-release coupling and/or releasable coupling. By using the couplings  182  in place of permanently connecting the coils  14   a ,  14   b  to the inlet and outlet headers  174 ,  178 , the assemblies  138  are permitted to be removed and/or replaced to accommodate a varying heat load or to permit serviceability of a damaged assembly  138 . 
     The condenser assembly  170  also includes an oversized outlet header  178  that also acts as a receiver for the liquid refrigerant discharged from the coils  14   a ,  14   b . One or more liquid refrigerant outlets  186  may extend from the oversized outlet header  178  to distribute the liquid refrigerant to the one or more evaporators in the refrigeration system. 
       FIG. 11  illustrates a fourth construction of a condenser assembly  190  including a two-row assembly  138 , with three separate and distinct fluid circuits, in a parallel configuration  158  between multiple inlet headers  194  and multiple outlet headers  198 . The two-row assembly  138  includes two microchannel condenser coils  118  grouped in a fluid series connection. As previously explained, the coils  118  each include respective baffles  122 ,  130  in the inlet and outlet manifolds  126 ,  134  to establish separate and distinct fluid circuits through the assembly  138 . Like the assemblies  138  of  FIG. 10 , the assembly  138  of  FIG. 11  may utilize fluid-tight couplings  182  to permit removal and/or replacement of the assembly  138  to accommodate a varying heat load or to permit serviceability of a damaged assembly  138 . 
       FIG. 12  illustrates a fifth construction of a condenser assembly  202  including a single-row assembly  150  between an inlet header  206  and an outlet header  210 . The single-row assembly  150  includes four microchannel condenser coils  64   a ,  64   b  grouped in a fluid parallel connection. The coils  64   a ,  64   b  are inclined with respect to the inlet and outlet headers  206 ,  210 , such that the footprint of the condenser assembly  202  is reduced (compared to the assembly  62  of  FIG. 4 , for example). Although  FIG. 12  generally illustrates the coils  64   a ,  64   b , it should be known that any of the coils  14   a ,  14   b ,  64   a ,  64   b ,  98 , or  118  may be used in forming the assembly  150 . 
     As indicated by  FIGS. 1 ,  4 , and  10 – 12 , the condenser assemblies  10 ,  62 ,  170 ,  190 ,  202  can be relatively small or relatively large. If a relatively large heat load must be satisfied, a relatively large condenser assembly (such as the assembly  170  of  FIG. 10 ) having a plurality of assemblies  138 ,  142 ,  146 , or  150  may be used. However, if a relatively small heat load must be satisfied, a relatively small condenser assembly (such as the assemblies  10 ,  62  of  FIGS. 1 and 4 , respectively) having only one assembly  138 ,  142 ,  146 ,  150  may be used. The condenser assemblies  10 ,  62 ,  170 ,  190 ,  202  are shown for exemplary reasons only, and are not meant to limit the spirit and/or scope of the present invention.