Patent Publication Number: US-11397060-B2

Title: Heat exchanger panel and method for mounting thereof to a rack structure

Description:
CROSS-REFERENCE 
     The present application claims priority from European Patent Application No. 19315108.1, filed on Aug. 30, 2019, the entirety of which is incorporated herein by reference. 
     FIELD OF TECHNOLOGY 
     The present technology relates generally to heat exchanger stacks as well as to methods for mounting heat exchanger panels to a rack structure. 
     BACKGROUND 
     Buildings are often equipped with heat management systems to regulate heat within the building. In certain types of buildings, heat management may be a particularly crucial consideration due to the intended use of the building. For instance, data centers, which store an extensive amount of heat-generating electronic equipment, typically implement a sizable heat management system to evacuate heat from the data center. 
     For example, data centers are often equipped with dry coolers installed on the roof of the building that houses the data center. Heated fluid (e.g., heated water) extracted from the data center (e.g., collected at the server level) is circulated to the dry coolers where the fluid transfers its heat into the ambient air pulled into the dry coolers. The heated air is then discharged into the ambient air and the now cooled fluid is recirculated back into the data center and the process is repeated. 
     It has been proposed to build a dry cooler tower including vertical dry cooler stacks, whereby various dry coolers are stacked vertically one on top of the other such that their respective fan assemblies are oriented to discharge heated air horizontally instead of vertically as is more typical. This has been shown to minimize recycling of heated air by adjacent dry coolers as the heated air is discharged into a common zone that is surrounded by the dry cooler stacks. However, such dry cooler towers can be difficult to assemble, as a rack structure has to be provided and the different components of each dry cooler separately mounted thereto, including the heat exchanger panels of the dry coolers which are typically heavy (e.g., 300-400 kg) and therefore require heaving machinery to manipulate. In addition, as the heat exchanger panels are of a considerable size, installing the heat exchanger panels onto (or dismounting the heat exchanger panels from) the rack structure usually requires a significant amount of space to be kept clear on the side of the rack structure from which it is intended to install/remove the heat exchanger panels. Thus, while the dry cooler stacks may not be too big in size, they may still have a significant footprint in the environment in which they are installed as additional space has to be kept clear to allow the installation or removal of the heat exchanger panels. 
     Thus there is a desire for a heat exchanger stack and a method for mounting a heat exchanger panel to a rack structure that alleviates at least in part some of these drawbacks. 
     SUMMARY 
     It is an object of the present technology to ameliorate at least some of the inconveniences present in the prior art. 
     According to one aspect of the present technology, there is provided a heat exchanger stack. The heat exchanger stack includes a rack structure and a plurality of heat exchangers supported by the rack structure. The rack structure includes: a plurality of vertical legs; a plurality of laterally-extending horizontal members extending between and interconnecting laterally-adjacent ones of the vertical legs; a plurality of longitudinally-extending horizontal members extending between and interconnecting longitudinally-adjacent ones of the vertical legs; a plurality of lower wheel guiding members, each lower wheel guiding member having a horizontal portion extending horizontally and an angled portion that is angled relative to the horizontal portion; and a plurality of upper wheel guiding members vertically spaced from the lower wheel guiding members, each of the upper wheel guiding members extending at least partly horizontally. The heat exchangers are disposed above one another. Each heat exchanger includes a fan assembly mounted to the rack structure and a heat exchanger panel mounted to the rack structure. The fan assembly includes a fan impeller rotatable about a fan rotation axis extending horizontally. The heat exchanger panel includes: a frame having an upper end and a lower end opposite the upper end; a tubing arrangement supported by the frame and configured to circulate fluid therein, the tubing arrangement having an inlet and an outlet; a plurality of fins in thermal contact with the tubing arrangement, the fins being spaced apart from one another for air to flow therebetween and through the heat exchanger panel; and a plurality of wheels mounted to the frame. Each of the wheels is rotatable about a respective axis extending generally laterally. The wheels are configured to engage respective ones of the lower and upper wheel guiding members of the rack structure for guided mounting of the heat exchanger panel on the rack structure. The wheels include: an upper set of wheels mounted to the upper end of the frame, the upper set of wheels including a first upper wheel and a second upper wheel spaced apart from one another; and a lower set of wheels mounted to the lower end of the frame, the lower set of wheels including a first lower wheel and a second lower wheel spaced apart from one another. Each upper wheel engages a corresponding upper wheel guiding member and each lower wheel engages the horizontal portion of a corresponding lower wheel guiding member so that the heat exchanger panel is translatable horizontally. 
     In some embodiments, the first upper wheel and the second upper wheel are spaced apart from one another by a first distance, and the first lower wheel and the second lower wheel are spaced apart from one another by a second distance. The first distance is different from the second distance. 
     In some embodiments, the first distance is greater than the second distance. 
     In some embodiments, a ratio of the first distance over the second distance is between 1.1 and 1.5. 
     In some embodiments, for each heat exchanger panel: the frame has a first lateral end and a second lateral end; the first and second upper wheels are spaced laterally outwardly from the first and second lateral ends of the frame; and the first and second lower wheels are disposed laterally inwardly from the first and second lateral ends of the frame. 
     In some embodiments, for each heat exchanger panel, the frame includes: an upper frame member defining the upper end of the frame, the upper frame member defining a channel extending laterally, and a lower frame member defining the lower end of the frame, the lower frame member defining a channel extending laterally. For each heat exchanger panel, the heat exchanger panel also includes a plurality of wheel mounts for mounting at least one of the wheels to the frame. Each of the wheel mounts includes: an elongated rail inserted within the channel defined by one of the upper and lower frame members, the elongated rail being removably connected to the one of the upper and lower frame members; and at least one mounting bracket interconnecting one of the at least one of the wheels to the elongated rail. 
     In some embodiments, the elongated rail is connected to the one of the upper and lower frame members by a plurality of fasteners extending from a front face to a rear face of the one of the upper and lower frame members. 
     In some embodiments, each of the at least one mounting bracket has a first portion extending parallel to the elongated rail and a second portion extending perpendicularly to the first portion, the one of the at least one of the wheels being connected to the second portion. 
     In some embodiments, at least one of the wheel mounts includes at least one lifting bracket; each of the at least one lifting bracket is connected to a corresponding one of the at least mounting bracket; and each of the at least one lifting bracket defines an opening for connecting a lifting device to the heat exchanger panel and lift the heat exchanger panel therefrom. 
     According to another aspect of the present technology, there is provided a method for mounting a heat exchanger panel to a rack structure. The method includes: lifting the heat exchanger panel via lifting brackets connected to a frame of the heat exchanger panel; lowering the heat exchanger panel until lower wheels mounted to a lower end of the frame of the heat exchanger panel are received and supported by respective lower wheel guiding members of the rack structure; rolling the heat exchanger panel downwardly by engagement of the lower wheels with the lower wheel guiding members, a portion of each of the lower wheel guiding members being inclined to guide the lower wheels downwardly; supporting upper wheels mounted to an upper end of the frame on upper wheel guiding members of the rack structure that are disposed vertically higher than the lower wheel guiding members; and translating the heat exchanger panel horizontally on the lower and upper wheel guiding members into a final position of the heat exchanger panel whereby the heat exchanger panel is in an inclined position such that a longitudinal axis of the heat exchanger panel, extending from the upper end to the lower end of the frame, is angled relative to a vertical axis. 
     In some embodiments, the method also includes, prior to lifting the heat exchanger panel, connecting the lifting brackets to a hoist mounted to an upper part of the rack structure in order to lift the heat exchanger panel via the hoist. 
     In some embodiments, the method also includes, prior to lowering the heat exchanger panel, affixing upper and lower extension portions of respective ones of the upper and lower guiding members to the rack structure, the upper and lower extension portions extending rearwardly of the rack structure; and after the upper wheels are supported by the rack structure, removing the upper and lower extension portions from the upper and lower guiding members. 
     In some embodiments, in the final position of the heat exchanger panel, the upper wheels and the lower wheels are adjacent to vertical legs of the rack structure so that the vertical legs support a load of the heat exchanger panel. 
     In some embodiments, the method also includes, prior to lifting the heat exchanger panel, removably connecting wheel mounts to the upper and lower ends of the frame of the heat exchanger panel, the wheel mounts interconnecting the wheels to the frame of the heat exchanger panel, said removably connecting comprising: inserting a rail of each wheel mount into one of: an upper channel defined by an upper frame member of the frame defining the upper end of the frame; and a lower channel defined by a lower frame member of the frame defining the lower end of the frame; and affixing the rail of each wheel mount to one of the upper frame member and the lower frame member via fasteners extending from a front face to a rear face of the one of the upper frame member and the lower frame member. 
     In some embodiments, while lowering the heat exchanger panel, an axis of the lower wheels describes a downward and generally vertical lower wheel path. The method also includes: prior to supporting the upper wheels on the upper wheel guiding members, reclining the heat exchanger panel so that the upper end of the frame of the heat exchanger panel pivots about the axis of the lower wheels, an axis of the upper wheels thereby describing an arcuate wheel path that intersects the lower wheel path. 
     Embodiments of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein. 
     Additional and/or alternative features, aspects and advantages of embodiments of the present technology will become apparent from the following description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: 
         FIG. 1  is a perspective view of a dry cooler stack in accordance with an embodiment of the present technology; 
         FIG. 2  is a perspective view, taken from a front, right side, of a rack structure of the dry cooler stack of  FIG. 1 ; 
         FIG. 3  is a right side elevation view of the rack structure of  FIG. 2 ; 
         FIG. 4  is front elevation view of a heat exchanger panel of a dry cooler of the dry cooler stack of  FIG. 1 ; 
         FIG. 5  is a side elevation view of the heat exchanger panel of  FIG. 4 ; 
         FIG. 6  is a side elevation view of part of the rack structure of  FIG. 2  with a heat exchanger panel in a first position while it is being mounted to the rack structure; 
         FIG. 7  is a side elevation view of the part of the rack structure of  FIG. 6  with the heat exchanger panel in a second position while it is being mounted to the rack structure; 
         FIG. 8  is a side elevation view of the part of the rack structure of  FIG. 6  with the heat exchanger panel in a final position while it is being mounted to the rack structure; 
         FIG. 9  is a perspective view, taken from a front, left side, of a part of the rack structure of  FIG. 2  with a bottommost heat exchanger panel mounted thereto in its final position; 
         FIG. 10  is another perspective view of the heat exchanger panel of  FIG. 9  with many components of the rack structure removed for clarity; 
         FIG. 11  is a right side elevation view of part of the rack structure of  FIG. 2  in accordance with an alternative embodiment, with a heat exchanger panel shown being mounted thereto; 
         FIG. 12  is a right side elevation view of part of the rack structure of  FIG. 11  mounted with the dry coolers, and with removable components of the rack structure removed therefrom; 
         FIG. 13  is a perspective view of a lower wheel guiding member of the rack structure of  FIG. 11 ; 
         FIG. 14  is a perspective view of part of an upper end of the heat exchanger panel of  FIG. 4 ; 
         FIG. 15  is a perspective view of a cross-section of part of the upper end of the heat exchanger panel of  FIG. 4 ; and 
         FIG. 16  is another perspective view of the cross-section of the part of the upper end of the heat exchanger panel of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a heat exchanger stack  10  configured to cool fluid flowing therethrough. In particular, in this embodiment, the heat exchanger stack  10  is a dry cooler stack  10  including a plurality of dry coolers  12 . However, it is contemplated that the heat exchanger stack  10  may comprise a plurality of any other suitable type of heat exchanger other than a dry cooler (e.g., a condenser, a chiller, etc.). 
     The dry cooler stack  10  includes a rack structure  14  supporting the dry coolers  12  on a support surface. In use, the rack structure  14  is anchored to the support surface by fasteners. The support surface may be any suitable support surface. For instance, in this embodiment, the support surface is a surface surrounding a building. However, in other embodiments, the support surface could be part of a structure purposefully built to support the rack structure  14 . The rack structure  14  will be described in greater detail further below. 
     The dry coolers  12  of the dry cooler stack  10  are installed on the rack structure such that their respective fan assemblies  16  are on a front side of the dry cooler stack  10  and therefore the dry coolers  12  of the dry cooler stack  10  discharge heated air toward the front side of the dry cooler stack  10 . 
     More specifically, as shown in  FIGS. 1 and 12 , each dry cooler  12  includes a heat exchanger panel  42 , a fan assembly  16 , and a plurality of enclosing panels  20 ,  21  which are mounted to the rack structure  14  to form the dry cooler  12 . Together, the heat exchanger panel  42 , the fan assembly  16  and the enclosing panels  20 ,  21  define an interior space of the dry cooler  12 . With reference to  FIGS. 4 and 5 , each dry cooler  12  functions by pumping heated water (extracted from inside the building in this example) through a tubing arrangement  60  of the heat exchanger panel  42  while simultaneously pulling in ambient air between a plurality of fins  33  ( FIG. 4 ) of the heat exchanger panel  42  (as illustrated by arrow A in  FIG. 12 ) to absorb heat from the heated water. Specifically, the ambient air is pulled in through the heat exchanger panel  42  by the corresponding fan assembly  16  of the dry cooler  12  which has a fan impeller  34  that is rotated by a motor (not shown) about a fan rotation axis FA. As air is pulled in through the heat exchanger panel  42  into the interior space of the dry cooler  12 , heat is transferred from the water circulating in the heat exchanger panel  42  to the air. The heated air is then discharged from the interior space of the dry cooler  12  through the fan assembly  16 . The water circulating in the heat exchanger panel  42  is thus cooled and is recirculated back into the building. This process is performed by each dry cooler  12  of the dry cooler stack  10 . 
     As will be described in greater detail below, the heat exchanger panels  42  of the dry coolers  12  are configured to facilitate mounting of the heat exchanger panels  42  to the rack structure  14 . In particular, the heat exchanger panels  42  are provided with rack-engaging members that engage respective guiding members of the rack structure  14 . 
     Returning now to  FIGS. 1 to 3 , in this embodiment, the rack structure  14  has four stories, thus allowing four rows of dry coolers  12  to be installed one on top of the other onto the rack structure  14 . More specifically, with reference to  FIGS. 2 and 3 , the rack structure  14  includes two rack units  18  which are affixed to one another to form the rack structure  14 . Each rack unit  18  makes up half of a depth D of the rack structure  14 . As can be seen in  FIG. 3 , a plurality of connectors  40  are provided to connect the two rack units  18  to one another and thereby homogenize forces exerted on the rack structure  14 . In this embodiment, each connector  40  is X-shaped and flat. Providing two separate rack units  18  to form the rack structure  14  and connecting them via the connectors  40  allows building a relative tall structure which can support the load of the dry coolers  12  mounted thereto as well as loads applied thereto by environmental factors such as winds and snow. Furthermore, this may allow reducing a risk of buckling of the sheet metal components from which the rack structure  14  is made. 
     Both rack units  18  are configured similarly and thus only one of the rack units  18  will be described in detail below. It is to be understood that the description applies to the other rack unit  18  as well. 
     The rack unit  18  includes four vertical legs  20  positioned at the corners of the rack unit  18  to define the rectangular shape of the rack unit  18 . A flange  31  is provided at the lower end of each vertical leg  20  for anchoring the rack unit  18  to the support surface on which the rack unit  18  is mounted. The vertical legs  20  are linked by laterally-extending horizontal members  22  which extend between and interconnect laterally-adjacent ones of the vertical legs  20 . The horizontal members  22  define the number of stories of the rack structure  14 . In this embodiment, each rack unit  18  has five horizontal members  22 . The rack unit  18  also has longitudinally-extending horizontal members  24  extending between and interconnecting longitudinally-adjacent ones of the vertical legs  20 . The horizontal members  22 ,  24  are generally vertically aligned with one another. Moreover, each rack unit  18  also has a plurality of diagonal connecting members  26  which extend diagonally between vertically-adjacent ones of the longitudinally-extending horizontal members  24 . As such, the diagonal connecting members  26  are disposed on each lateral side of the rack unit  18 . 
     The components of the rack unit  18  can be fastened to one another in any suitable way. In this embodiment, the components of the rack sub-unit  18  are bolted to one another. It is contemplated that, in other embodiments, the components of the rack sub-unit  18  could be welded to one another. 
     As mentioned above, the connectors  40  interconnect the two rack units  18  to one another. In particular, two ends of each X-shaped connector  40  are fastened (e.g., bolted or welded) to one of the vertical legs  20  of one of the rack units  18  and the two other ends of the X-shaped connector  40  are fastened to an adjacent vertical leg  20  of the other rack unit  18 . 
     As will be described in greater detail below, the rack structure  14  and the heat exchanger panels  42  of the dry coolers  12  are configured so as to facilitate mounting of the heat exchanger panels  42  onto the rack structure  14  to assemble the dry coolers  12 . Notably, as shown in  FIGS. 2 and 3 , the rack structure  14  is provided with two rails  75  which support a respective hoist system  57  for lifting the heat exchanger panels  42  so as to mount them in their defined place on the rack structure  14 . The rails  75  are laterally spaced from one another and connected to the upper ends of the rack units  18 . In particular, each rail  75  is fastened to two laterally-spaced upper brackets  25  of each rack unit  18 . The upper brackets  25  are connected to the topmost longitudinally-extending horizontal members  24 . In this embodiment, each rail  75  is an I-beam and the upper brackets  25  are shaped to be fastened to a central portion of the rails  75  between the wide ends thereof. As such, each rail  75  is slidable between the upper brackets and is fastened thereto. The rails  75  protrude from the rear side of the rack structure  14 . A respective hoist system  57  is connected near the end of each rail  75 . The hoist system  57  may be manually operated or electrically operated. 
     As shown in  FIGS. 6 to 10 , in order to receive the wheeled heat exchanger panels  42  within the rack structure  14 , the rack structure  14  is provided with a plurality of lower guiding members  70  and a plurality of upper guiding members  74  which are vertically spaced from one another. In particular, a pair of the lower guiding members  70  and a pair of the upper guiding members  74  together receive a corresponding heat exchanger panel  42 . In this embodiment, the guiding members  70 ,  74  receive respective wheels of the heat exchanger panels  42  and therefore may be referred to as lower and upper “wheel guiding members”  70 ,  74 . 
     As best seen in  FIGS. 9 and 10 , the lower wheel guiding members  70  are supported by and connected to the laterally-extending horizontal members  22  and laterally-extending wheel guide supports  23 . Each lower wheel guiding member  70  includes a horizontal portion  73  and an angled portion  71  that is angled relative to the horizontal portion  73 . The horizontal and angled portions  71  are elongated members. Notably, the angled portion  71  extends upwardly and rearwardly from the horizontal portion  73 . More specifically, in this embodiment, as shown in  FIG. 6 , the angled portion  71  extends at an angle θ of approximately 15° relative to the horizontal portion  73 . In some embodiments, the angled portion  71  may extend at an angle between 10° and 75° relative to the horizontal portion  73 . Notably, this range of values of the angle θ may provide a compact path of the heat exchanger panels  42  when being mounted to the rack structure  14 , as will be discussed in greater detail below. 
     As shown in  FIGS. 6 and 10 , the horizontal portion  73  extends longitudinally and is supported by and connected to longitudinally-adjacent ones of the horizontal members  22 . The angled portion  71  is connected, at its lower end, to the horizontal portion  73  and, near to its upper end, to a corresponding one of the laterally-extending wheel guide supports  23 . The laterally-extending wheel guide supports  23  extend between and are connected to laterally-adjacent ones of the vertical legs  20 . 
     The lower wheel guiding members  70  are configured to receive and guide the wheels of the heat exchanger panel  42 . Therefore, in this embodiment, the angled and horizontal portions  71 ,  73  have a generally U-shaped cross-sectional profile. Specifically, in this embodiment, as shown in  FIG. 10 , the angled portion  71  has opposite parallel walls  130  defining a channel  131  therebetween. Similarly, the horizontal portion  73  has opposite parallel walls  140  defining a channel  141  therebetween. When a heat exchanger panel  42  is being mounted to the rack structure  14 , lower wheels of the heat exchanger panel  42  roll on bottom surfaces extending between the walls  130 ,  140  while the parallel walls  130 ,  140  guide the lower wheels, thereby preventing the wheels from disengaging the lower wheel guiding members  70 . 
     As shown in  FIGS. 9 and 10 , the upper wheel guiding members  74  are supported by and connected to the vertical legs  20  via support brackets  35 ,  37 . In particular, the upper wheel guiding members  74  are disposed atop the support brackets  35 ,  37  which are affixed to the vertical legs  20 . Each upper wheel guiding members  74  is elongated and has two parallel walls  120  defining a channel  121  therebetween. When a heat exchanger panel  42  is being mounted to the rack structure  14 , upper wheels of the heat exchanger panel  42  roll on a bottom surface extending between the walls  120  while the parallel walls  120  guide the wheels, thereby preventing the wheels from disengaging the upper wheel guiding members  74 . 
     As shown in  FIGS. 6 to 8 , in this embodiment, the lower and upper wheel guiding members  70 ,  74  extend rearwardly past the rearmost vertical legs  20 . As such, in this embodiment, the lower and upper wheel guiding members  70 ,  74  extend past the depth DP of the rack structure  14 . However, it is contemplated that in other embodiments, the lower and upper wheel guiding members could not extend rearwardly past the rearmost vertical legs  20 . 
     For instance, with reference to  FIGS. 11 to 13 , in some embodiments, the rack structure  14  has lower wheel guiding members  70 ′ and upper wheel guiding members  74 ′ for receiving the wheeled heat exchanger panels  42 . In particular, a pair of the lower wheel guiding members  70 ′ and a pair of the upper wheel guiding members  74 ′ together receive a corresponding heat exchanger panel  42 . In this embodiment, the lower and upper wheel guiding members  70 ′,  74 ′ do not extend rearwardly past the rearmost vertical legs  20  of the rack structure  14 . However, in order to allow the wheels of the heat exchanger panel  42  to be received “outside” of the rack structure  14 , removable lower guide extensions  77 ′ and removable upper guide extensions  76 ′ are provided which are removably connectable to the lower and upper wheel guiding members  70 ′,  74 ′ respectively. 
     As shown in  FIG. 13 , each lower wheel guiding member  70 ′ has a horizontal portion  73 ′ and an angled portion  71 ′ extending at an angle relative to the horizontal portion  73 ′. The horizontal portion  73 ′ is supported by and connected to longitudinally-adjacent ones of the horizontal members  22 . The angled portion  71 ′ is connected, at its lower end, to the horizontal portion  73 ′ and, at its upper end, to a corresponding one of the laterally-extending wheel guide supports  23 . In particular, flanges  80 ′ extending outwardly from the parallel walls  78 ′ are connected to the horizontal members  22 , and supporting legs  82 ′ extending downwardly from the upper end of the angled portion  71 ′ are connected to the laterally-extending wheel guide supports  23 . In this embodiment, the angle formed between the angled portion  71 ′ and the lower portion  73 ′ is less than that between the angled portion  71  and the lower portion  73  described above, namely since the angled portion  71 ′ is connected to the lower portion  73 ′ at a point further rearward. As such, the vertical distance between the laterally-extending wheel guide supports  23  and corresponding horizontal members  22  is smaller. 
     The angled and horizontal portions  71 ′,  73 ′ have a generally U-shaped cross-sectional profile. Notably, the horizontal portion  73 ′ has two parallel opposite walls  78 ′ and a channel defined therebetween. Similarly, the angled portion  71 ′ has two parallel opposite walls  85 ′ and a channel defined therebetween. When a heat exchanger panel  42  is being mounted to the rack structure  14 , lower wheels of the heat exchanger panel  42  roll on bottom surfaces  83 ′,  79 ′ extending between the walls  78 ′,  85 ′ while the parallel walls  78 ′,  85 ′ guide the lower wheels, thereby preventing the wheels from disengaging the lower wheel guiding members  70 ′. 
     The upper wheel guiding members  74 ′ are substantially similar to the upper wheel guiding members  74  described above except that they are size so as to not extend rearward from the rearmost vertical legs  20 . The upper wheel guiding members  74 ′ will therefore not be described in detail herein. 
     The removable lower guide extensions  77 ′ and removable upper guide extensions  76 ′ have a generally U-shaped cross-sectional profile for receiving wheels of the heat exchanger panels  42  therein. As shown in  FIG. 11 , the removable lower and upper guide extensions  77 ′,  76 ′ are connected respective ones of the lower wheel guiding members  70 ′ (to the angled portion  71 ′ thereof specifically) and to the upper wheel guiding members  74 ′ via connecting brackets  88 ′ which surround the bottom walls of the lower wheel guiding members  70 ′ and the upper wheel guiding members  74 ′ for connection to the lower and upper guide extensions  77 ′,  76 ′. 
     The heat exchanger panels  42 , which are configured to transfer heat from the fluid circulating therein into the air flowing therethrough, will now be described in greater detail below with reference to  FIGS. 4 and 5 . Since the heat exchanger panels  42  are all identical in this embodiment, only one of the heat exchangers  42  will be described in detail herein. It is to be understood that the same description applies to the other heat exchanger panels  42 . 
     The heat exchanger panel  42  has a frame  43  for supporting the various components of the heat exchanger  42 . The frame  43  has an upper end  44  and a lower end  46  opposite the upper end  44 , as well as opposite lateral ends  47 ,  48 . Together, the ends  44 ,  46 ,  47 ,  48  define a generally rectangular shape of the frame  43  and of the heat exchanger panel  42 . The tubing arrangement  60  of the heat exchanger panel  42 , which as mentioned above is configured to circulate fluid therein, is supported by the frame  43 . As can be seen in  FIG. 4 , a portion  62  of the tubing arrangement  60  extends in a serpentine path across a majority of a width and a length of the frame  43  within the boundaries defined by the ends of the frame  43 . A header portion  65  of the tubing arrangement  60  extends outside of the frame  43 , adjacent to the lateral end  48  thereof, and defines an inlet  63  and an outlet  64  for respectively receiving fluid into and discharging fluid out of the tubing arrangement  60 . It should be understood that the path traced by the portion  42  of the tubing arrangement  60  has been simplified in the drawings for practicality; the path traced thereby may vary in other embodiments. The fins  33  of the heat exchanger panel  42  are in thermal contact with the portion  62  of the tubing arrangement  60  so as to increase a heat exchange surface area of the heat exchanger panel  42 . The fins  33  are spaced apart from one another to allow air to flow therebetween and into the interior space of the corresponding dry cooler  12 . 
     The heat exchanger panel  42  is provided with a plurality of rack-engaging members  50 ,  52  which are mounted to the frame  43  and which, as will be described in greater detail below, are configured to engage respective guiding members of the rack structure  14  for guided mounting of the heat exchanger panel  42  on the rack structure  14 . In this embodiment, the rack-engaging members  50 ,  52  are wheels  50 ,  52  which are configured to roll on respective wheel guiding members of the rack structure  14 . The wheels  50 ,  52  are mounted to the frame  43  in such a way as to be rotatable about a respective axis  51 ,  53  that extends generally laterally (i.e., in a side-to-side direction of the heat exchanger panel  42 ). The wheels  50 ,  52  include an upper set of wheels  50  mounted to the upper end  44  of the frame  43  and a lower set of wheels  52  mounted to the lower end  46  of the frame  43 . The upper set of wheels  50  includes two upper wheels  50  spaced apart from one another by a distance D 1 . The wheels  50 ,  52  also include a lower set of wheels  52  mounted to the lower end  46  of the frame  43 . The lower set of wheels  52  includes two lower wheels  52  spaced apart from one another by a distance D 2 . 
     It is contemplated that the wheels  50 ,  52  could be other types of rack-engaging members such as, for example, anti-friction members that slide on the guiding members  70 ,  74  of the rack structure  14 . 
     In order to ensure that a path of the heat exchanger panel  42  when being mounted to the rack structure  14  is relatively compact such that the heat exchanger panel  42  stays relatively close to the rack structure  14  when being mounted thereto, the heat exchanger panel  42  is designed such that the distances D 1  and D 2  are different from one another (i.e., unequal to one another). As such, as shown in  FIG. 4 , the upper wheels  50  are spaced laterally outwardly from the lateral ends  47 ,  48  of the frame  43  of the heat exchanger panel  42 . On the other hand, the lower wheels  52  are spaced laterally inwardly from the lateral ends  47 ,  48  of the frame  43  of the heat exchanger panel  42 . In particular, in this embodiment, the distance D 1  is greater than the distance D 2 . For instance, a ratio of the distance D 1  over the distance D 2  may be between 1.1 and 1.5. In this embodiment, the ratio of the distance D 1  over the distance D 2  is approximately 1.2 (±0.1). As will be understood, the lower and upper wheel guiding members described above are positioned in accordance with the distances D 1 , D 2  so as to receive and guide the wheels  50 ,  52 . 
     As will be shown below when describing the path of the heat exchanger panel  42  when being mounted to the rack structure  14 , this difference between the distances D 1 , D 2  ensures that the upper wheels  50  and the lower wheels  52  move along different planes when the heat exchanger panel  42  is being mounted to the rack structure  14  and therefore that the path of the axis of the upper wheels  50  can intersect the path of the axis of the lower wheels  52  during installation on the rack structure  14 . This may provide a compact installation path of the heat exchanger panel  42  as it is being installed onto the rack structure  14  which results in a relatively small amount of space being required on a rear side  15  of the rack structure  14  to mount the heat exchanger panels  42  to the rack structure  14 . In turn, this results in footprint savings in the environment in which the dry cooler stack  10  is being installed as less space is required to remain unused behind the rack structure  14  to install the heat exchanger panels  42  thereto. This is particularly useful for example along a facade of a building or the roof of a building such as that housing a data center where a considerable amount of equipment has to be provided on the roof to service the data center properly. 
     With reference to  FIGS. 4 and 14 to 16 , the wheels  50 ,  52  are mounted to the upper and lower ends  44 ,  46  of the frame  43  of the heat exchanger panel  42  via wheel mounts  90 . Notably, in this embodiment, an upper wheel mount  90  is configured to mount the upper wheels  50  to the upper end  44  of the frame  43  while a lower wheel mount  90  is configured to mount the lower wheels  52  to the lower end  46  of the frame  43 . 
     As shown in  FIGS. 14 and 15 , the upper wheel mount  90  includes a removable connector  94  that is attached to the upper end  44  of the frame  43 . In particular, the removable connector  94  of the upper wheel mount  90  is connected to an upper frame member  45  of the frame  43  which defines the upper end  44  thereof. More specifically, the removable connector  94  is inserted within a channel  49  defined by the upper frame member  45  and which extends laterally between the opposite lateral ends  47 ,  48  of the frame  43 . As shown in  FIG. 15 , the channel  49  has a bottom surface  96 . In this embodiment, the removable connector  94  is an elongated rail having a generally rectangular cross-sectional profile, and the channel  49  is appropriately shaped and dimensioned to receive the removable connector  94  therein. In order to secure the removable connector  94  in the channel  49  of the upper frame member  45 , fasteners  102  ( FIGS. 15, 16 ) extend through the upper frame member  45  and the removable connector  94  transversally to their direction of elongation (i.e., from a front face to a rear face of the heat exchanger panel  42 ). The fasteners  102  are bolts which are received by nuts on an opposite side of the heat exchanger panel  42 . 
     As shown in  FIG. 4 , the frame  43  also has a lower frame member  54  defining the lower end  46  of the frame  43  and which is identical to the upper frame member  45 , namely defining a channel  49  extending laterally. The lower wheel mount  90  also has a removable connector which is similar to the removable connector  94  and is removably connected to the lower frame member  54  of the frame  43 . The removable connector of the lower wheel mount  90  does not extend across the entire width of the frame  43 , as can be seen in  FIG. 4 . 
     As will be understood, the wheel mounts  90  allow the wheels  50 ,  52  to be selectively removable from the heat exchanger panel  42  simply by removing the fasteners  102  and removing the removable connector  94  from the channel  49 . This may facilitate maintenance and/or replacement of the heat exchanger panel  42 . Notably, if the heat exchanger panel  42  is defective or otherwise needs replacement, the wheels  50 ,  52  can be easily removed from the heat exchanger panel  42  and installed on a replacement heat exchanger panel having the same configuration suitable for the removable connector  94  of each wheel mount  90  to be inserted into a corresponding frame member of the frame  43 . 
     Returning to  FIGS. 4 and 15 , the upper wheel mount  90  also includes two mounting brackets  91 , with each mounting bracket  91  interconnecting one of the wheels  50  to the removable connector  94 . Each mounting bracket  91  has a first portion  98  extending parallel to the removable connector  94  and a second portion  92  extending perpendicularly to the first portion  98 . The corresponding wheel  50  is connected to the second portion  92  such that the axis  51  thereof extends laterally. In particular, as shown in  FIG. 15 , an axle  100  (which may be a fastener) to which the wheel  50  is mounted extends through the second portion  92  of the mounting bracket  91  and is secured in place by a nut  101 . A spring  103  is disposed between the outer surface of the second portion  92  and the wheel  50 . 
     The upper wheel mount  90  also includes a lifting bracket  93  connected to each mounting bracket  91 . Each lifting bracket  93  extends perpendicularly from the first portion  98  of the corresponding mounting bracket  91  and defines an opening for connecting a lifting device, such as the hoist system  57 , to lift the heat exchanger panel  42  from the lifting bracket  93 . A locking member  95  is also provided as part of the upper wheel mount  90  to secure the heat exchanger panel  42  in its final position on the rack structure  14  (via fasteners). 
     The lower wheel mount  90  is configured in substantially the same manner as the upper wheel mount  90 . However, the lower wheel mount  90  does not include the lifting brackets  93  since the heat exchanger panel  42  is intended to be lifted from its upper end. 
     Although in this embodiment, each wheel mount  90  mounts two of the wheels  50  or  52  to the frame  43  of the heat exchanger panel  42 , it is contemplated that, in other embodiments, each wheel mount  90  may mount a single one of the wheels  50  or  52  to the frame  43 . For instance, in such embodiments, four wheel mounts  90  may be provided to mount one of the upper wheels  50  or one of the lower wheels  52  to the frame  43 . Moreover, it is contemplated that in such embodiments, the removable connector  94  may extend along an end portion of the width of the frame  43 . 
     Other configurations of the wheel mounts  90  are contemplated. For instance, it should be noted that  FIGS. 9 and 10  show a different embodiment of the wheel mounts. Notably, alternative wheel mounts  110  are provided having mounting brackets that are shaped differently than those of the wheel mounts  90 . 
     Turning now to  FIGS. 6 to 8 , a method for mounting one of the heat exchanger panels  42  to the rack structure  14  will be described in greater detail. 
     As an initial step, the heat exchanger panel  42  is brought to a position behind the rack structure  14 . For example, the heat exchanger panel  42  can be brought there by a pallet jack. Notably, due to the ease of mounting provided by the wheeled heat exchanger panel  42  and the rack structure  14  of the present technology, a heavier machine such as a forklift (which occupies more space and is significantly heavier) is not needed to mount the heat exchanger panel  42  to the rack structure  14  as would typically be the case for mounting a conventional heat exchanger panel to a conventional rack structure. Moreover, this affords more space behind the rack structure  14  as space does not have be reserved for allowing the forklift behind the rack structure  14 . In addition, a concrete slab which would typically be provided behind the rack structure for a forklift can be foregone. 
     Once the heat exchanger panel  42  is in position behind the rack structure, in this embodiment, first, in order to lift the heat exchanger panel  42 , the lifting brackets  93  of the heat exchanger panel  42  are connected to the hoist system  57  which is mounted to the upper part of the rack structure  14 . 
     With reference to  FIG. 6 , once the heat exchanger panel  42  is connected to the hoist system  57  via the lifting brackets  93 , the heat exchanger panel  42  is lifted via the lifting brackets  93  and held in a generally vertical orientation behind the rack structure  14 , on the rear side thereof from which the heat exchanger panel  42  is to be installed. 
     Next, the heat exchanger panel  42  is lowered until the lower wheels  52  are received and supported by the lower wheel guiding members  70 . During this lowering motion, the axis  53  of the lower wheels  52  describes a downward and generally vertical lower wheel path PL. In embodiments in which the upper and lower removable guide extensions  76 ′,  77 ′ are used, prior to lowering the heat exchanger panel  42  onto the lower and upper wheel guiding members, the upper and lower removable guide extensions  76 ′,  77 ′ of the upper and lower wheel guiding members  74 ′,  70 ′ are affixed to the rack structure  14 . 
     With reference to  FIG. 7 , once the lower wheels  52  are supported by the lower wheel guiding members  70 , the heat exchanger panel  42  is rolled downwardly by engagement of the lower wheels  52  with the lower wheel guiding members  70 . Since the angled portion  71  of each of the lower wheel guiding members  70  is inclined, lowering the heat exchanger panel  42  causes this rolling of the heat exchanger panel  42  downwardly. With continued reference to  FIG. 7 , next, the heat exchanger panel  42  is reclined so that the upper end  44  of the frame  43  pivots about the axis  53  of the lower wheels  52 . The axis  51  of the upper wheels  50  thus describes an arcuate upper wheel path PU that intersects the lower wheel path PL at a point IN. Notably, as discussed above, this intersection at the point IN between the upper and lower wheel paths PU, PL, whereby the upper wheel path PU extends substantially transversally to the lower wheel path PL, is provided by the difference between the distances D 1 , D 2  which allows the upper and lower wheels  50 ,  52  to move on different planes from one another when being mounted to the rack structure  14 . As mentioned above, this allows keeping the path of the heat exchanger panel  42  as it is being mounted to the rack structure  14  relatively compact such that less space is required to be kept clear behind the rack structure  14 . For instance, with reference to  FIG. 7 , the upper wheel path PU extends, at its rearmost point, at a distance DM from the rearmost vertical leg  20 . In this embodiment, the distance DM is approximately 3 meters. This is significantly smaller than is typical for conventional dry cooler stacks where an upper end of the heat exchanger panel would be at distance of 5 meters or more from the corresponding rack structure. 
     After the heat exchanger panel  42  has been moved forward (i.e., further down on the lower wheel guiding members  70 ) and reclined backward sufficiently, the upper wheels  50  are supported on the upper wheel guiding members  74 . At this stage, if the upper and lower removable guide extensions  76 ′,  77 ′ were used, they can be removed from the upper and lower wheel guiding members  74 ′,  70 ′. 
     Next, as shown in  FIG. 8 , the heat exchanger panel  42  is translated horizontally on the lower and upper wheel guiding members  70 ,  74  into its final position. As can be seen, in its final position, the heat exchanger panel  42  is in an inclined positioned such that a longitudinal axis LA of the heat exchanger panel  42 , extending from the upper end  44  to the lower end  46  of the frame  43 , is angled relative to a vertical axis (extending vertically relative to the support surface on which the rack structure  14  is supported). For instance, in this embodiment, in its final position, the longitudinal axis LA extends at an angle of approximately 60° relative to a vertical axis. It is contemplated that the longitudinal axis LA could extend at different angles relative to the vertical axis in other embodiments. Furthermore, as can be seen in  FIG. 8 , in the final position of the heat exchanger panel  42 , the upper wheels  50  and the lower wheels  52  are adjacent to the rearmost and frontmost vertical legs  20  of the rack structure  14  respectively. As such, in the final position, it is the vertical legs  20  that primarily support a load of the heat exchanger panel  42 . This can be useful as the lower and upper wheel guiding members  70 ,  74  do not have to fulfil a load-supporting role and instead just guide the wheels  50 ,  52 , therefore the members of the rack structure  14  to which the lower and upper wheel guiding members  70 ,  72  are connected do not need to be designed to support the load of the heat exchanger panel  42 . 
     Modifications and improvements to the above-described implementations of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.