Patent Publication Number: US-2023148257-A1

Title: Airflow control louver for bidirectional airflow cooling

Description:
TECHNICAL FIELD 
     Embodiments presented in this disclosure generally relate to providing airflow and cooling in and through computer systems such as data center switches and storage systems. More specifically, embodiments disclosed herein describe a dynamic airflow control louver system which provides for efficient and effective cooling for computing systems, where the computing systems may be installed within mounting equipment in various configurations. 
     BACKGROUND 
     In large scale computing environments, such as data centers, flexibility in installing and replacing computer systems and other electronic components is a key design requirement. This flexibility and versatility allows for quick and simple replacements and upgrades of computer systems. For example, individual systems installed within a large scale networked system may break down or require hardware technology upgrades. In order to allow operators of the computer systems to access, upgrade, repair, and replace these systems the computer systems are designed with several optional installation configurations within the overall mounting equipment. 
     Additionally, as computer systems increase in power and complexity, the heat output of these systems also increases. While some design improvements to these higher powered systems provide for efficient cooling, these improvements often eliminate flexible and efficient installation within large scale computing environments. Providing efficient cooling to increasingly high power computer systems, without sacrificing flexible installation and configuration, remains a challenge. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate typical embodiments and are therefore not to be considered limiting; other equally effective embodiments are contemplated. 
         FIGS.  1 A and  1 B  illustrate an electronic device with an airflow control louver in a first position, according to one embodiment. 
         FIGS.  2 A and  2 B  illustrate an electronic device with an airflow control louver in a second position, according to one embodiment. 
         FIGS.  3 A and  3 B  illustrate additional views of the airflow control louver, according to embodiments. 
         FIGS.  4 A- 4 C  illustrate a mounted airflow control louver, according to embodiments. 
         FIG.  5    illustrates an electronic device with a fan, according to one embodiment. 
         FIG.  6    illustrates electronic devices mounted in a server rack, according to embodiments. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially used in other embodiments without specific recitation. 
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Overview 
     One example embodiment includes an electronic device. The electronic device includes a heatsink; a first airflow path in a first direction, where the first airflow path passes through the heatsink; a second airflow path in a second direction, where the first airflow path passes through the heatsink; and a third airflow path in the second direction, where the third airflow path bypasses the heatsink. The electronic device also include an airflow control louver, where the airflow control louver in a first position directs cooling air along the first airflow path, and where the airflow control louver in a second position allows cooling air to flow along the second airflow path and the third airflow path. 
     Another example embodiment includes a network switch. The network switch includes a heatsink, at least one optical network component and a first airflow path in first direction, a second airflow path and a third airflow path in a second direction. The first airflow path passes through the heatsink, the first airflow path passes through the heatsink, and the third airflow path bypasses the heatsink to flow to the at least one optical network component. The network switch also include an airflow control louver, where the airflow control louver in a first position directs cooling air along the first airflow path, and where the airflow control louver in a second position allows cooling air to flow along the second airflow path and the third airflow path. 
     Another example embodiment includes an airflow control louver system. The airflow control louver system includes an airflow control louver positioned within an enclosed electronic device; a first airflow path in a first direction; a second airflow path in a second direction; and a third airflow path in the second direction, where the airflow control louver in a first position directs cooling air along the first airflow path, and where the airflow control louver in a second position allows cooling air to flow along the second airflow path and the third airflow path. 
     Example Embodiments 
     Large scale computer systems are an increasingly utilized form of providing networked computing and storage solutions. For example, large scale data centers provide both primary and redundant computing and storage options for a variety of services including governmental, commercial, and consumer computer network based services. While some data centers and large scale computer systems provide single services on uniform computer equipment, modern data centers increasingly rely on basic standard equipment and allow for customized computer systems. For example, a data center may utilize standard floorplan layouts and equipment racks, while allowing a wide variety of computer systems to be installed within those equipment racks. For example, a standard rack may hold several different types of computer equipment including network switches, storage drives, etc. This wide variety of computer systems allows data center customers/administrators to implement replacements and upgrades with ease while maintaining service. Customers have come to rely on flexibility both in the types of equipment as well as the flexibility of installation options within the racks/equipment of the data center. 
     One example of flexible installation is whether a computer system or network switch is installed with the ports (or other types of system connections) of the switch facing a cool air aisle in a data center or a hot air aisle in the data center. For example, an operator may install a network switch in a port side intake (PSI) or port side exhaust (PSE) configuration based on the needs of the individual or overall networked system. In some cases, such as the PSE installation, additional cooling air is needed in the individual network switch or electronic device to ensure that the heat sensitive components within the switch receive an adequate cooling airflow. 
     Indeed, a primary concern for data centers and large scale computer systems is providing efficient cooling to these systems. Failing to keep the individual computer systems cool can cause decreased performance and damage to the computer systems. In some examples, data centers are designed to provide cooling airflow to each of the equipment racks and the individual computer systems. The individual computer systems in turn include cooling systems, such as fans, which move cooler ambient air through the computer system to cool the heat producing internal components of the computer system. 
     As the processing power of these individual computer systems increases, the cooling needs also increase to keep the systems functioning properly. In some cases, heat sensitive components within the computer system require cool airflow that can cool both the system in general, but also provide cooling airflow to specific heat sensitive components within the system. The systems described herein provide an electronic device with an airflow control louver which provides for cooling airflow to be efficiently routed through the electronic device in two different directions which in turn allows for multiple installation configurations for electronic devices with high powered heat sensitive components. 
       FIGS.  1 A and  1 B  illustrate an electronic device, device  101 , with an airflow control louver system, including a louver  105 , in a first position, and  FIGS.  2 A and  2 B  illustrate the device  101  with the louver  105  in a second position. The device  101  may be embodied as a network switch or type of electronic device.  FIG.  1 A  is a side view  100  of the device  101  and  FIG.  1 B  is a top view  150  of the device  101 . In some examples, the device  101 , as shown in  FIG.  1 A , is installed within a server rack in a port side air intake or PSI configuration, where cooling air is drawn into the device  101  via the port side of the device  101  as described in more detail in relation to  FIG.  6   . The PSI configuration provides a cooling flow to a port side of the device  101 , side  112 , which in turn provides a cooling airflow to heat sensitive components, components  120 , in the device  101  before the cooling airflow flows to a heatsink  115  for the device  101 . 
     In some examples, the device  101  is an enclosed chassis which includes the side  112 , a bottom side  114 , a top side  113 , and a side  111 , where side  111  is an opposite side to the side  112 , as well as sidewall  152 , and sidewall  152  forming the enclosed chassis. In some examples, the side  111  is an exhaust side when the airflow control louver is in the first position. In the PSI configuration, cooling air  131  enters the device  101  via an air intake on the port side of the device  101 , side  112 , and travels along a first airflow path, path  130 , through the components  120  in a first direction. 
     In some examples, the components  120  include ports, optical connections, communication devices (e.g., retimers), application-specific integrated circuits (ASICs) and other heat sensitive electronic or communication components. While a heatsink  115  in the device  101  may provide some cooling capacity to these components, in one embodiment the primary cooling provided these components is via the ambient cooling air, i.e. heat dissipates from the components  120  to the cooling air  131 . This heat transfer allows for the components  120  to function properly even as the power and heat generation from the components  120  increases. The cooling air  132  on a downstream side of the components  120  has a higher ambient air temperature than the cooling air  131  due to the heat transfer from the components  120 . 
     In order to maximize cooling efficiency in the device  101  an amount of cooling airflow passing through the heatsink  115  should also be maximized. The louver  105  is positioned in the device  101  to direct the cooling airflow along the path  130  including directing substantially all of the cooling air  132  into the heatsink  115 . In some examples, the heatsink  115  provides the cooling capacity and temperature regulation for the main ASIC and other internal electronic components in the device  101 . 
     In this example, the louver  105  is attached to the top side  113  of the device  101 . The airflow control louver may also function as a passive activation louver such that at a time when there is no airflow through the device  101 , gravitational forces act on the louver  105  to position the louver in the first position as shown in  FIGS.  1 A- 1 B . The louver  105 , in the first position, also makes contact with a heatsink  115  in the device  101 . A width  116  of the heatsink  115  is illustrated in  FIG.  1 B . In some examples, the width  116  is approximately the same width as the internal width of the device  101 , occupying an entire width of the internal chassis of the device  101 . For example, as shown in top view  150 , the heatsink extends from sidewall  151  to sidewall  152  of the enclosed chassis of the device  101 . 
     A height  117  of the heatsink  115  is shown in  FIG.  1 A , where the height  117  is less than the height of the device  101 , leaving a headspace  118  above the heatsink  115  within a chassis of the device  101 . In some examples, this headspace allows for cooling airflow to cool the components  120  in a second configuration. However, in the first or PSI configuration shown in  FIGS.  1 A and  1 B , the cooling airflow is primarily directed into the heatsink  115 . 
     The louver  105  in the first position prevents cooling airflow from entering the headspace  118  and instead directs substantially all of the cooling air  132  through the heatsink  115 . For example, the path  130  provides an air path for cooling air  132  to flow from the side  112  and the components  120  through the heatsink  115  and to the side  111  as heated exhaust  133 . In the PSI configuration shown in  FIGS.  1 A and  1 B , the cooling air traveling along the path  130  ensures that the device  101  overall remains within safe and optimal operating temperatures via heatsink  115  and that the components  120  remain within safe and optimal operating temperatures via the cooling air  131 . 
     In some examples, when airflow is reversed in device  101 , that is cooling air enters the heatsink  115  prior to encountering the components  120 , the exhaust from the heatsink  115  may not have a low enough temperature to maintain optimal or safe operating temperatures for the components  120 . Some solutions, such as increasing an airflow rate of the cooling air in the device  101 , increase the fan noise and other requirements of the device  101  with marginal improvements in the cooling capacity provided to the components  120 . In some more optimal examples described herein, the airflow control louver is activated into a second position in order to provide cooling air directly to components  120  as descried in  FIGS.  2 A and  2 B . 
       FIGS.  2 A and  2 B  illustrate the device  101  with the louver  105  in the second position.  FIG.  2 A  is a side view  200  of the device  101  and  FIG.  2 B  is a top view  250  of the device  101 . In some examples, the device  101 , as shown in  FIG.  2 A , is installed within a server rack in a port side air exhaust or PSE configuration, where cooling air is drawn into the device  101  via a back side of the device  101  as described in more detail in relation to  FIG.  6   . The PSE configuration provides a cooling flow to a back side of the device  101 , side  111 , which in turn provides a cooling airflow to the heatsink  115  before cooling the components  120  on the port side of the device. 
     In this example, the side  112  is the exhaust side when the airflow control louver is in the second position. In the second or PSE configuration, cooling air  231  enters the device  101  on the back side of the device  101 , via an air intake on the side  111  and a portion of the cooling air  231 , cooling air  232   a , travels along a third airflow path in a second direction, path  240 , through the heatsink  115 . Heat transfers from the heatsink  115  to the cooling air  232   a . In some examples, the second direction of the third airflow in the second direction flows in an opposite direction of the first airflow path, path  130 , described in  FIG.  1   . 
     In some examples, exhaust  233  from the heatsink  115  has an ambient temperature that is too warm to properly cool the components  120 , thus relying on the exhaust  233  for cooling the components  120  may cause the components  120  to overheat and malfunction. In order to maximize cooling efficiency in the device  101  a second portion of the cooling air  231  should be provided directly to the components  120 . 
     The louver  105  is positioned in the device  101  to direct or allow the cooling airflow along a path  240  including allowing a portion of the cooling air  231 , i.e. cooling air  232   b , to bypass the heatsink via the headspace  118  and provide a direct cooling airflow to the components  120 . At a time when there is no airflow through the device  101 , gravitational forces act on the louver  105  to position the louver in the first position as shown in  FIGS.  1 A- 1 B , however, as airflow begins passing along the path  240 , the airflow moves the louver  105  into the second position adjacent to a top side of the device  101  by positive air pressure as discussed in relation to  FIG.  3 B . The louver  105 , in the second position allows for the cooling air  232   b  to bypass the heatsink and provide cooling airflow to the components  120 . In some examples, the cooling air  232   b  mixes with the exhaust  233  from the heatsink  115 , where the mix of the exhaust  233  and the cooling air  232   b  provides enough cooling flow to ensure that the components  120  continue to function properly and not overheat. 
     For example, the louver  105  in the second position does not block cooling airflow from entering the headspace  118  and instead provides a path for the cooling air  232   b  to pass above or otherwise bypass the heatsink  115 . For example, the path  130  provides an air path for cooling air  232   a  to flow from the side  111  through the heatsink  115  to the side  112  as heated exhaust  233 . In the PSE configuration shown in  FIGS.  2 A and  2 B , the cooling air traveling along a second airflow path in the second direction, path  230 , ensures that the device  101  overall remains within safe and optimal operating temperatures via the heatsink  115 . Additionally, the path  240  provides an air path for cooling air  232   b  to flow from the side  111  to the components  120  to provide cooler air than the exhaust  233  can provide to the heat sensitive components, ensuring that the components  120  remain within safe and optimal operating temperatures via the cooling air  232   b  and outputting the exhaust  235  from the device  101 . Additional details for the first and second positions of the louver  105  are described in relation to  FIGS.  3 A- 4 C . 
       FIG.  3 A  further illustrates airflow in the electronic device in a first configuration in a side view  300 . As shown in  FIG.  3 A , the cooling air  132  is shown as airflow portions  301  and  302 . The airflow portion  302  acts on the louver  105  which holds or seals the louver  105  against the heatsink  115 . In some examples, the louver  105  is held or sealed against a fin of the heatsink  115 . As cooling air flows through the device  101 , the portions  301  and  302  pass through the heatsink  115  as the heated air or exhaust  310 . 
       FIG.  3 B  further illustrates airflow in the electronic device in a second configuration in a side view  350 . For example, the cooling air  231  is shown as airflow portions  351  and  352 . The airflow portions  352  pass through the heatsink  115  and is passed through the heatsink  115  as exhaust  355 . The airflow portion  352  acts on the louver  105  and opens the louver allowing the portions  352  to bypass the heatsink  115 . In some examples, the portions  352  and the exhaust  355  mix prior to airflow  360  flowing to the components  120  shown in  FIGS.  2 A- 2 B . In some examples, the airflow  360  has a higher ambient temperature than the cooling air  231 ; however, the airflow  360  has a lower ambient temperature than the exhaust  355  and provides a sufficient cooling airflow to the components  120 . 
       FIG.  4 A  illustrates a side view of the louver  105  in the second position in a side view  400 . In some examples, the louver  105  is formed from a 38 gauge or 0.15 millimeter stainless steel alloy. The louver  105  may also be formed from carbon steel and rolled to include a hinge portion of the louver  105 . In some examples, the louver  105  is mounted to the top side  113  of the device  101 . For example, the hinge portion is mounted on a rod or one or more mounting pieces or lances  405  and the one or more lances  405  are connected to the top side  113  via mounts  410 . The louver  105  freely rotates about the lances  405  moving from the second position shown in  FIG.  4 A  to the first position shown in  FIG.  4 B  when no airflow is present or the device  101  is installed in the first/PSI configuration. 
     While shown in  FIGS.  1 A,  2 A, and  4 A- 4 B  as mounted directly to the top side  113  of the device  101 , the louver  105  and associated mounting components may be mounted to various other portions of the electronic device. For example, the device  101  may include various other components positioned above or around the heatsink. The louver  105  may be mounted to the additional component while preventing or allowing the air to enter the headspace above the heatsink, as described herein. In some examples, a weight of the louver  105  is such that the louver  105  may be moved between the two positions by airflow. 
       FIGS.  4 B and  4 C  illustrate the louver in the first position. As described above, the louver  105  is in the first position in side view  420  shown in  FIG.  4 B , where the louver  105  has freely swung down to the first position.  FIG.  4 C  shows front view  440  of the louver  105  in the first position, where the louver  105  is a same or approximately same width as the heatsink  115  and makes contact with the heatsink  115  in the first position. 
       FIG.  5    illustrates the device  101  with a fan  505 . In some examples, the fan  505  is positioned within the device  101  between the heatsink  115  and the side  111 . In some examples, the fan, in a first mode, pulls air through the device  101  when the device is installed in the first configuration and, in a second mode, pushes air through the device  101  when the device is installed in the second configuration as described in more detail in  FIG.  6   . While shown in  FIG.  5    in one example position, the fan  505  may be positioned at any position, within or outside of the device  101 , where the fan  505  moves air through the device  101  as described in relation to  FIGS.  1 A- 4 C . 
       FIG.  6    illustrates a server rack  605 . In some examples, the server rack  605  is installed in a data center with a typical floor layout where a first side of the server rack  605  faces a cool air aisle  610  and second side of the server rack  605  faces a warm air aisle  620 . Devices  101   a - 101   e  installed in the server rack draw cooling air  615  via the cool air aisle  610  and exhaust heated air  625  into the warm air aisle  620 . In some examples, the devices  101   a - 101   c  are installed in the rack  605  in the first configuration or PSI configuration where the respective fans  505  draw air along the paths  130  within the individual systems, as shown in  FIGS.  1 A- 1 B , and output exhaust air into the warm air aisle  620 . In some examples, the devices  101   d - 101   e  are installed in the rack  605  in the second configuration or PSE configuration where the respective fans  505  push air along the paths  230  and  240  as shown in  FIGS.  2 A- 2 B  and output exhaust air into the warm air aisle  620 . 
     In both of the optional configurations, the devices  101   a - 101   e  with the associated airflow control louver systems installed within the devices, provide the required heat dissipation via cooling airflow for both primary heatsinks in the devices as well as other heat sensitive components in the devices, despite which direction or configuration the devices are installed within the rack  605 . 
     In the current disclosure, reference is made to various embodiments. However, the scope of the present disclosure is not limited to specific described embodiments. Instead, any combination of the described features and elements, whether related to different embodiments or not, is contemplated to implement and practice contemplated embodiments. Additionally, when elements of the embodiments are described in the form of “at least one of A and B,” it will be understood that embodiments including element A exclusively, including element B exclusively, and including element A and B are each contemplated. Furthermore, although some embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the scope of the present disclosure. Thus, the aspects, features, embodiments and advantages disclosed herein are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the invention” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s).