Patent Publication Number: US-2017368914-A1

Title: Removable external bulkhead for transportation refrigeration unit

Description:
BACKGROUND 
     The subject matter disclosed herein relates to transportation refrigeration systems. More specifically, the present disclosure relates to managing and controlling air input into transportation refrigeration systems. 
     Referring to  FIG. 6 , on tractor-trailer applications, where a tractor  100  is coupled to and pulls a trailer  102 , refrigeration units  104  for such applications (referred to as “transportation refrigeration units”) are typically mounted to a front wall of the trailer  102 , so the transportation refrigeration unit  104  is positioned between the tractor  100  and the trailer  102 . 
     The transportation refrigeration unit  104  is contained in a housing, with the housing having a mesh or grated panel  106  on its front face as an intake for air into the condenser section of the transportation refrigeration unit  104 . Due to its position at the front face between the tractor  100  and trailer  102 , much of the air  108  passing through the panel  106  into the condenser section is actually recirculated air from a transportation refrigeration unit outlet and/or heat from the tractor engine, both of which are of high temperature compared to ambient temperature, and as a result reduce unit performance and efficiency. 
     The problem is exacerbated in tractor trailer systems that are equipped with fuel saving options. These options include routing tractor engine heat underneath the tractor  100 , and also aerodynamic fairings  110  positioned on a roof of the tractor  100  and/or along a side of the tractor  100 . The tractor engine heat routing results in an increase in high temperature exhaust air ingested by the transportation refrigeration unit, while the aerodynamic fairings  110  divert flow of lower temperature ambient air around the transportation refrigeration unit, so that the ambient air is much less likely to reach the panel  106 . 
     BRIEF SUMMARY 
     In one embodiment, a cover for a transportation refrigeration unit includes a substantially solid front panel and one or more airflow inlet openings located at a top of the cover to direct an airflow from outside the cover into the transportation refrigeration unit. 
     Additionally or alternatively, in this or other embodiments, a top panel is operably connected to the front panel, the one or more airflow inlet openings positioned at the top panel. 
     Additionally or alternatively, in this or other embodiments the one or more airflow inlet openings include one or more scoops to direct the airflow into the transportation refrigeration unit. 
     Additionally or alternatively, in this or other embodiments one or more baffles are secured to the cover to direct the airflow from the one or more airflow inlet openings to a selected portion of the transportation refrigeration unit. 
     Additionally or alternatively, in this or other embodiments the one or more baffles are formed integral to the cover. 
     Additionally or alternatively, in this or other embodiments one or more airflow outlet openings are positioned below the one or more airflow inlet openings to direct the airflow from inside the transportation refrigeration unit to outside the cover. 
     Additionally or alternatively, in this or other embodiments one or more outlet baffles are secured to the cover to direct the airflow from the transportation refrigeration unit to the one or more airflow outlet openings. 
     In another embodiment, a transportation refrigeration system includes a refrigeration unit operably connectible to a cargo compartment and configured to direct cooling airflow into the cargo compartment thereby cooling the cargo compartment to a selected temperature. A cover is secured to the refrigeration unit including a substantially solid front panel and one or more airflow inlet openings positioned at a top of the cover to direct an inlet airflow from outside the cover into the refrigeration unit. 
     Additionally or alternatively, in this or other embodiments a top panel is operably connected to the front panel, the one or more airflow inlet openings positioned at the top panel. 
     Additionally or alternatively, in this or other embodiments the one or more airflow inlet openings include one or more scoops to direct the inlet airflow into the refrigeration unit. 
     Additionally or alternatively, in this or other embodiments one or more baffles secured to the cover to direct the inlet airflow from the one or more airflow inlet openings to a selected portion of the refrigeration unit. 
     Additionally or alternatively, in this or other embodiments the one or more baffles are formed integral to the cover. 
     Additionally or alternatively, in this or other embodiments one or more airflow outlet openings are positioned below the one or more airflow inlet openings to direct an outlet airflow from inside the refrigeration unit to outside the cover. 
     Additionally or alternatively, in this or other embodiments the cover is installed over a condenser air mesh of the refrigeration unit. 
     In yet another embodiment, a refrigerated container system includes a container having a cargo compartment for transportation of a cargo and a transportation refrigeration unit secured to the container and including a refrigeration unit operably connectible to the cargo compartment and configured to direct cooling airflow into the cargo compartment thereby cooling the cargo compartment to a selected temperature. A cover is secured to the refrigeration unit and includes a substantially solid front panel and one or more airflow inlet openings positioned at a top of the cover to direct an inlet airflow from outside the cover into the refrigeration unit. 
     Additionally or alternatively, in this or other embodiments the one or more airflow inlet openings include one or more scoops to direct the inlet airflow into the refrigeration unit. 
     Additionally or alternatively, in this or other embodiments one or more baffles are secured to the cover to direct the inlet airflow from the one or more airflow inlet openings to a selected portion of the refrigeration unit. 
     Additionally or alternatively, in this or other embodiments the one or more baffles are formed integral to the cover. 
     Additionally or alternatively, in this or other embodiments one or more airflow outlet openings are positioned below the one or more airflow inlet openings to direct an outlet airflow from inside the refrigeration unit to outside the cover. 
     Additionally or alternatively, in this or other embodiments the cover is installed over a condenser air mesh of the refrigeration unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an embodiment of a tractor-trailer system with a transportation refrigeration unit; 
         FIG. 2  is a perspective view of an embodiment of a transportation refrigeration unit; 
         FIG. 3  is a cross-sectional view of an embodiment of an airflow inlet for a transportation refrigeration unit; 
         FIG. 4  is a partially exploded view of an embodiment of a transportation refrigeration unit; 
         FIG. 5  is a side view of an embodiment of a transportation refrigeration unit; and 
         FIG. 6  is a side view of a prior tractor-trailer system. 
     
    
    
     The detailed description explains the invention, together with advantages and features, by way of examples with reference to the drawings. 
     DETAILED DESCRIPTION 
     Shown in  FIG. 1  is an exemplary embodiment of a tractor-trailer system  10 . The system includes a tractor  12 , or cab, which includes an engine  14  to drive the system  10 , and compartment for the operator (not shown). The tractor  12  is coupled to a trailer  16 , which includes a cargo compartment  18  to transport a cargo  20 . A transportation refrigeration unit (TRU)  22  is coupled to the trailer  16  and provides cooling airflow into the cargo compartment  18  to maintain the cargo  20  at a selected temperature. While the term “trailer” is used throughout this description, one skilled in the art will readily appreciate that the subject matter disclosed herein may be applied to other refrigerated cargo container systems. The TRU  22  includes components typical of such a device, such as a compressor, a condenser, an expansion device and an evaporator that operate on a flow of refrigerant circulating through the TRU  22 . In some embodiments, since tractor fuel consumption is a main driver in the cost of operating a tractor-trailer system  10 , the tractor-trailer system  10  may include aerodynamic devices fixed to that tractor  12  and/or the trailer  16 . These devices may include aerodynamic fairings  24  fixed to a roof  26  of the tractor  12  and/or fixed to a side  28  of the tractor  12  as shown in  FIG. 1 . It is to be appreciated, however, that the shown fairings  24  are merely exemplary, and fairings  24  of other shapes/sizes/locations may be utilized. The fairings  24  are configured to direct ambient airflow  30  around the tractor-trailer system  10  smoothly, thereby reducing fuel consumption. 
     Referring to  FIG. 2 , the TRU  22  is contained in a housing  32  at a front wall  34  of the trailer  16 . The housing  32  has a front panel  36 , furthest from the front wall  34 , and a top  38  and bottom  40 . In a typical system, the front wall includes a mesh or grill to allow airflow into the TRU via the front wall. In many tractor-trailer systems, especially those with aerodynamic fairings, the airflow ingested through the grill is higher than ambient temperature, because the airflow often includes hot air ingestion from the tractor engine or from recirculating TRU outlet air. In the embodiments of the present disclosure, however, the front panel  36  is solid, and absent any airflow inlet. As shown in  FIG. 2 , airflow inlets  42  for the TRU  22  are located at the top  38  of the housing  32 , and airflow outlets  44  are located at the bottom  40 , or at a sidewall  46  of the housing  32 . The airflow inlet  42  location at the top  38  of the housing  32  prevents hot air ingestion from the tractor engine or from recirculating TRU outlet air. 
     In some embodiments, as shown in  FIG. 3 , the airflow inlets  42  may include scoops  48  to divert and guide passing ambient airflow  50  into the airflow inlets  42 . In some embodiments, such as the embodiment of  FIG. 4 , the front panel  36  is installed over an existing condenser air mesh  54  of the TRU  22 , instead of replacing the condenser air mesh as in, for example, the embodiment of  FIG. 2 . The front panel  36  is secured over the econdenser air mesh  54  via, for example, a frame  56 . The embodiment of  FIG. 4  may be removed and installed as selected by a user, and may be added as an accessory after initial production of the TRU. 
     Referring now to  FIG. 5 , in some embodiments, the front panel  36  may include additional features, such as baffles  52 , ribs or other such elements to guide airflow from the airflow inlets  42  to selected portions of the TRU  22 , for example, the condenser. The baffles  52  are located between the front panel  36  and the TRU  22 . In some embodiments, the baffles  52  are perforated, are mesh or otherwise include openings to allow airflow diffusion prior to entering the condenser. A solid baffle  52  may extend across the airflow inlet  42  at a bottom of the airflow inlet  42  to finally direct the airflow into the condenser. Further, additional outlet baffles may be utilized to guide exhaust airflow toward the airflow outlets  44 . In one embodiment, the front panel  36  is formed from a plastic material by, for example, injection molding, blow molding or thermoforming. In some embodiments, scoops  46 , baffles  52  and/or outlet baffles are formed integral to the front panel  36 . Alternatively, the scoops  48 , baffles  52  and/or outlet baffles may be formed independently from the front panel  36  and assembled thereto by fasteners and/or adhesives. The front panel  36  is secured to underlying structure of the TRU  22  and/or the housing  32  via fasteners, for example, screws. 
     Utilizing the front panel  36  of the present disclosure prevents hot air ingestion from the tractor engine or reingestion of TRU outlet airflow into the TRU resulting in performance improvement of the TRU. Further, this improvement is accomplished without redesign of the underlying TRU. Not only is performance improved by preventing ingestion of the high-temperature airflow into the TRU, but with this configuration, condenser performance is improved due to the condenser operation being changed from a front-feed of airflow to a top-feed of airflow. 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.