Patent Publication Number: US-9844166-B2

Title: Techniques for controlling vapor pressure in an immersion cooling tank

Description:
RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 13/757,713, filed Feb. 1, 2013, which is fully incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to information handling systems and in particular to a system and method for cooling of information handling systems that are operated within an immersion cooling vessel. Still more particularly, aspects of the disclosure relate to techniques for managing vapor pressure within an immersion cooling vessel. 
     2. Description of the Related Art 
     As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
     Large scale server systems are examples of information handling systems. These servers can perform significant workloads and generate and/or dissipate a large amount of heat during their operation. Due in part to the large amount of heat generated, these servers are typically rack mounted and cooled via fans built on the devices and a large system of fans attached to or placed directly behind, or adjacent to, the rack of servers. As the need for access to greater and greater processing and storage resources continues to expand, limitations arise surrounding available space for expansion, building and equipment costs, and communication latency. This trend creates a need to increase the density of server systems (i.e., the amount of processing power and/or storage placed on a single server, the number of servers placed in a single rack, and/or the number of servers and/or racks deployed on a single server farm. With the increasing processing and/or storage density in these rack-based server systems, the thermal challenges that result continue to be one of the biggest obstacles. Conventional fan based cooling systems require large amounts of power, and the cost of power required to drive high flow fans increases exponentially with the increase in server densities. Additionally, cooling of electronic components with air requires special consideration for air-quality parameters including: temperature, humidity, altitude, and airborne particulate and contamination. What is therefore needed is an efficient, low power usage system and method for cooling these servers and server systems. 
     BRIEF SUMMARY 
     Disclosed are a system, a method, and a multi-phase heat transfer immersion cooling tank that enables direct cooling of information handling systems, such as servers, by submerging and operating the physical information handling systems in a volatile (i.e., low boiling point) liquid within the multi-phase heat transfer immersion cooling tank. 
     According to one aspect of the disclosure, a plurality of techniques for controlling and/or mitigating the buildup of pressure within the immersion cooling tank is provided in order to maintain the integrity of the tank (from high pressure vapor leakage, etc.). One embodiment provides a pressure control system within a 2-phase heat transfer immersion cooling tank. The system includes: a differential pressure transducer that measures a differential pressure between a first vapor pressure internal to the immersion tank and a second pressure outside of the immersion tank; a condenser inflow valve assembly that controls a flow rate of condensation liquid within the condenser located within the immersion tank; and control logic that, in response to the measured differential pressure exceeding a pre-set threshold difference, triggers the condenser inflow valve assembly to increase a flow rate of the condensation liquid in order to reduce an amount of vapor within the immersion tank and bring the measured differential pressure back to below the threshold difference. 
     According to one embodiment, the pressure control system includes an external facility that provides/supplies the condensation fluid as a condensation liquid. The external facility is located at a point horizontally above the condenser to allow the condensation fluid to flow via a difference in gradient and wherein the flow rate of condensation fluid through the condenser (i.e., the amount of condensation liquid that flows per unit time through the condenser) is controlled by a position of the condenser inflow valve assembly, which is in turn controlled/determined by input received from the controller. 
     Another embodiment provides a pressure control system that includes: a cooling mechanism that reduces a temperature of a portion of condensation liquid stored external to the immersion cooling tank; and control logic that, in response to the measured differential pressure exceeding a pre-set threshold difference, triggers the condenser inflow valve assembly to: provide one or both of an increased flow rate of the condensation liquid and a lower ambient temperature of the condensation liquid, in order to increase vapor condensation due to a faster rate of heat absorption from the rising vapor and decrease the amount of vapor in the tank. The increase in the rate of vapor condensation reduces the amount of vapor within the immersion tank and thus reduces the associated pressure. 
     In one or more embodiments, the pressure control system further includes: a condenser fluid flow controller that is connected to the differential pressure transducer. The differential pressure transducer is employed in a feedback loop connected with the condenser fluid flow controller, and the condenser fluid flow controller dynamically modulates (increases or decreases) flow of condensation fluid into the condensers, such that the vapor mass within the upper volume of the immersion cooling tank can be kept substantially constant. In one embodiment, the condenser fluid flow controller dynamically modulates the flow in order to maintain an amount of vapor within an upper volume of the immersion cooling tank within a pre-established operating range. 
     According to one embodiment, the control logic comprises a proportional-integral-derivative (PID) algorithm coupled with a variable displacement solenoid valve on a supply-side of a facility cooling loop. The solenoid valve is controlled by feedback provided by the differential pressure transducer. 
     According to one additional aspect of the disclosure, the pressure control system comprises: a bellows expansion lid positioned above the condensers within the immersion cooling tank and which in response to an increase in pressure of the rising vapor above a threshold normal pressure, moves upwards into the lid of the immersion tank to substantially eliminate the increase in pressure by virtue of volume expansion. The bellows expansion lid also moves downwards to a base location in response to the amount of pressure within the tank reducing to below a low threshold pressure level. The surface area of the bellows expansion lid can be close to the surface area of the inner tank perimeter or can be much smaller. When much smaller in size, the position of the bellows expansion lid within the upper tank area can be selected based on empirical measurements to maximize the effects of the expansion on the pressure gradient within the tank. 
     The above summary contains simplifications, generalizations and omissions of detail and is not intended as a comprehensive description of the claimed subject matter but, rather, is intended to provide a brief overview of some of the functionality associated therewith. Other systems, methods, functionality, features and advantages of the claimed subject matter will be or will become apparent to one with skill in the art upon examination of the following figures and detailed written description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description of the illustrative embodiments can be read in conjunction with the accompanying figures. It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the figures presented herein, in which: 
         FIG. 1  illustrates one embodiment of an example information handling system with internal processing components and externally located hard disk drives (HDDs), according to one aspect of the disclosure; 
         FIG. 2  is a schematic diagram of an information handling system configured as a server with an upper section of hard disk drives when oriented to stand on a back section of the chassis, according to one or more embodiments; 
         FIG. 3  is a schematic diagram of another example of an information handling system configured as a server with a set of external locally-connected hard disk drives, according to one or more embodiments; 
         FIG. 4  is a schematic diagram illustrating a first example internal structure of a two-phase vaporization-condensation immersion cooling tank with a dielectric cooling liquid that operates to provide cooling for processing components of one or more servers partially immersed in the cooling liquid with the server&#39;s hard disk drives located above the cooling liquid in the path of rising dielectric vapor, according to one or more embodiments; 
         FIG. 5  is a schematic diagram illustrating a second example internal structure of a two-phase vaporization-condensation immersion cooling tank configured to support cooling of the example server of  FIG. 3 , with external locally-connected hard disk drives suspended above the dielectric cooling liquid in the path of the rising dielectric vapor, according to one or more embodiments; 
         FIG. 6  provides various views of a rubber-based grommet that can be utilized within the immersion cooling tank to allow for insertion of power connectors and data cabling, while preventing leakage of the cooling liquid or vapor from the immersion cooling tank, according to one embodiment; 
         FIG. 7  is a flow chart illustrating one example of a general method for cooling HDDs within an immersion cooling vessel and controlling operating conditions within the immersion cooling tank via feedback control, according to one or more embodiments; 
         FIG. 8  illustrates a three dimensional view of an example immersion cooling tank such as presented by  FIGS. 4 and 5 , configured with multiple condenser sub-units to provide cooling of multiple partially immersed servers placed within a server rack, in accordance with one or more embodiments; 
         FIG. 9  is a facility exchange diagram showing the application of the vaporization-condensation cooling system to a larger heat exchange environment, according to one embodiment; 
         FIG. 10  illustrates a plurality of sequentially linked heat exchange loops utilized for cooling a target space with cycling of working fluids utilizing multiple heat exchanges and associated working fluids in tandem with a working fluid reservoir, according to one or more embodiments; 
         FIG. 11  illustrates an example of a system providing multiple condensation-vaporization and vaporization-condensation cycles of working fluid loops to effect a heat transfer and/or cooling of a target space, according to one embodiment; 
         FIG. 12  is an example immersion tank for cooling one or more partially immersed servers utilizing one of a plurality of circulating channels for condensation of the rising dielectric vapor and return of the condensate to the lower volume of the tank, according to one embodiment; 
         FIG. 13  illustrates examples of methods for gravitationally controlling a level of cooling liquid in a first immersion cooling tank utilizing a pipe connection to a secondary volume of cooling liquid, in accordance with one or more embodiments; 
         FIG. 14  is a flow chart illustrating a method of controlling the dielectric liquid level within an immersion cooling tank, in accordance with one or more embodiments; 
         FIG. 15  is a block diagram illustrating an aerial view of example daisy chaining of multiple immersion cooling tanks to maintain cooling fluid equilibrium across the multiple tanks within a data center, in accordance with one or more embodiments; 
         FIG. 16  illustrates an example vapor pressure control sub-system involving deployment of a bellows expansion lid within a tank cover of an immersion cooling tank having multiple adjacent bellows within the tank cover, according to one or more embodiments; 
         FIGS. 17A-17B  provides two additional views of an example vapor pressure control sub-system including multiple adjacent bellows within the tank cover of a single immersion cooling tank, in accordance with one embodiment; 
         FIG. 18  illustrates example detection and feedback control mechanisms deployed within an immersion cooling tank and which enable control of various operational conditions internal to the immersion cooling tank, including vapor pressure reduction, during operation of the tank as a cooling vessel, in accordance with one or more embodiments; 
         FIG. 19  illustrates an example proportional-integral-derivative (PID) algorithm that can be utilized within a pressure control system for an immersion cooling tank, in accordance with one embodiment; 
         FIG. 20  is a flow chart illustrating a method of controlling pressure build up within an immersion cooling tank, in accordance with one or more embodiments; 
         FIG. 21A  illustrates an example vertically-oriented server configuration in which a vapor deflector is provided to direct rising vapor bubbles away from upper components that are submerged in cooling liquid, according to one embodiment; 
         FIG. 21B  illustrates a second example of a vertically-oriented server configuration in which multiple vapor deflectors are provided to direct rising vapor bubbles away from upper portions of a single component and/or upper components that are submerged in cooling liquid, according to one embodiment; 
         FIG. 21C  illustrates an example of a high heat dissipating component that includes both deflector fins as well as heat fins attached to the surface of the component, according to one or more embodiments; 
         FIG. 22  is a three dimensional view of an example motherboard of a vertically-oriented liquid and vapor cooled immersion server (vLVCIS) having processing components and memory modules located on opposing surfaces of a shared motherboard, in accordance with one or more embodiments; 
         FIG. 23  presents a three dimensional view of an example vLVCIS with storage devices located vertically above the other functional components that are embedded on the opposing sides of the motherboard of  FIG. 22 , according to one or more embodiments; 
         FIG. 24  is a three dimensional schematic of an immersion server drawer having multiple side-by-side vLVCISes located therein, according to one or more embodiments; 
         FIG. 25  presents a three dimensional illustration of an example immersion server drawer cabinet providing a vapor condensation chamber for housing multiple immersion server drawers, according to one or more embodiments; and 
         FIG. 26  is a three dimensional schematic of a stand-alone, self-contained, immersion tank data center (ITDC) including an immersion tank with one or more servers partially immersed in a dielectric liquid to enable cooling of the server components during operation, according to one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides illustrative embodiments of various aspects of and/or different configurations and implementations of one or more systems, methods, and multi-phase heat transfer immersion cooling vessels that enable direct cooling of information handling systems, such as servers, by submerging at least a portion of the physical information handling systems in a dielectric liquid within a multi-phase heat transfer immersion cooling vessel. 
     The disclosure generally includes a plurality of different aspects and multiple different embodiments, and each aspect along with the associated embodiments are described in detail below within one of the titled Sections A-K. A first aspect of the general disclosure, presented in Section A, provides examples of an information handling system and of two different servers configured and/or oriented for use within a rack-based immersion cooling system. Section B, which describes the second aspect of the general disclosure, introduces the design and operation of an example immersion cooling tank, including the description of certain functional characteristics of the immersion cooling tank. A third aspect of the general disclosure is presented in Section C, which provides techniques for cooling hard disk drives (HDDs) of a server by exposing the HDDs to rising vapor from a boiling dielectric liquid in which the processing components are submerged for cooling during processing operations of the server. The fourth aspect of the general disclosure is presented in Section D, which introduces the innovative concept of submerging PDUs in order to prevent electrical arching and improve the efficiency of the PDUs when utilized within an immersion cooling vessel. A fifth aspect of the general disclosure is presented in Section E, which provides a unique design and functionality of the condenser with multiple rotatable condenser sub-units. A sixth aspect of the general disclosure is presented in Section F, which describes a methodology for cooling a target space and/or a device that involves stepped sequencing of multiple heat exchangers (or condensers) with different working fluids. A seventh aspect of the general disclosure is presented in Section G and includes a unique interconnection among multiple immersion tanks to allow cooling liquid levels to be gravitationally equalized across the multiple interconnected immersion tanks. An eight aspect of the general disclosure is presented in Section H, which provides a series of techniques for controlling and/or mitigating the buildup of pressure within the tank, as well as other control functions, in order to maintain the integrity of the tank (e.g., from high pressure vapor leakage, etc.). Sections I and J introduce several novel server design aspects including a vapor deflector for isolating processors, an immersion server, immersion server drawer, and an immersion server drawer-based cabinet, all designed to facilitate immersion-based liquid cooling of the processors and memory modules of the immersion server and vapor cooling of the HDDs. Finally, an eleventh aspect of the general disclosure is presented in Section K, which provides a Stand-alone Immersion Tank Data Center (SITDC) with self-contained cooling. 
     Additional functional aspects of the general disclosure are presented throughout the description of one or more of the sections. It is appreciated that the description of certain functional aspects of the disclosure within a particular section (rather than in a different section, for example) is presented in that section solely to simplify the order of presentation of information and does not and/or is not intended to limit the specific disclosure content to discrete implementation within only each identified section. Rather, the sections work together to provide a description of a single generally innovative concept with multiple different aspects and/or embodiment corresponding thereto. 
     In the following detailed description of exemplary embodiments of the disclosure, specific exemplary embodiments in which the disclosure may be practiced are described in sufficient detail to enable those skilled in the art to practice the disclosed embodiments. For example, specific details such as specific method orders, structures, elements, and connections have been presented herein. However, it is to be understood that the specific details presented need not be utilized to practice embodiments of the present disclosure. It is also to be understood that other embodiments may be utilized and that logical, architectural, programmatic, mechanical, electrical and other changes may be made without departing from general scope of the disclosure. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and equivalents thereof. 
     References within the specification to “one embodiment,” “an embodiment,” “embodiments”, or “one or more embodiments” are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of such phrases in various places within the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not for other embodiments. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. 
     It is understood that the use of specific component, device and/or parameter names and/or corresponding acronyms thereof, such as those of the executing utility, logic, and/or firmware described herein, are for example only and not meant to imply any limitations on the described embodiments. The embodiments may thus be described with different nomenclature and/or terminology utilized to describe the components, devices, parameters, methods and/or functions herein, without limitation. References to any specific protocol or proprietary name in describing one or more elements, features or concepts of the embodiments are provided solely as examples of one implementation, and such references do not limit the extension of the claimed embodiments to embodiments in which different element, feature, protocol, or concept names are utilized. Thus, each term utilized herein is to be given its broadest interpretation given the context in which that term is utilized. 
     Within the descriptions of the different views of the figures, the use of the same reference numerals and/or symbols in different drawings indicates similar or identical items, and similar elements can be provided similar names and reference numerals throughout the figure(s). The specific identifiers/names and reference numerals assigned to the elements are provided solely to aid in the description and are not meant to imply any limitations (structural or functional or otherwise) on the described embodiments. In the illustration of the various embodiments, two different figures can be provided that have overlaps and/or similarities in the components within the two figures (e.g.,  FIGS. 2 and 3 , and  FIGS. 4 and 5 ). In such instances, the descriptions of these figures can be presented together with associated similar reference numerals separated by commas and/or a slash. Some components that are not expected to be different from one implementation to the other are provided the same reference numerals within the figures, to simplify the descriptions of the figures. 
     Those of ordinary skill in the art will appreciate that the hardware components and basic configuration depicted in any of the figures illustrated by the drawings and described herein may vary. For example, the illustrative components within information handling system  100  ( FIG. 1 ), example server  200 ,  300  ( FIGS. 2 and 3 ), immersion server  2100 ,  2300  ( FIGS. 21 and 23 ), and/or immersion cooling vessels/tanks  400 ,  500 ,  800  ( FIGS. 4-5, 8 ), and other devices and systems are not intended to be exhaustive, but rather be representative of and highlight components that can be utilized to implement aspects of the present disclosure. For example, other devices/components may be used in addition to or in place of the hardware depicted. The depicted examples do not convey or imply any architectural or other limitations with respect to the presently described embodiments and/or the general disclosure. 
     A. Information Handling System and Server Configuration or Orientation for Rack-Based Immersion Cooling 
     Turning now to the figures,  FIG. 1  illustrates a block diagram representation of an example information handling system (IHS)  100 , with which one or more of the described features of the various embodiments of the disclosure can be advantageously utilized. For purposes of this disclosure, an information handling system, such as IHS  100  and/or server  200  ( FIG. 2 ) or server  300  ( FIG. 3 ) or immersion server  2200  ( FIG. 22 ) may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a handheld device, personal computer, a server, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. It is however appreciated that the information handling systems of the present disclosure are described as being primarily rack-based server systems. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disk drives, one or more network ports for communicating with external devices as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components. 
     Referring specifically to  FIG. 1 , example IHS  100  includes processing components  150  (referred to as “internal” components) that are physically located on the device chassis and other functional components located externally to the processing components  150  (referred to as “external” components). Included within processing components  150  are a plurality of processor(s)  105  coupled to system memory  110  via system interconnect  115 . System interconnect  115  can be interchangeably referred to as a system bus, in one or more embodiments. Also provided within the processing components  150  and coupled to system interconnect  115  is one or more storage controller(s)  120 , to which is coupled local internal storage  122  and local external storage  125 . Storage controller(s)  120  controls data storage operations on nonvolatile storage, of which local internal storage  122  and local external storage  125  are shown. 
     As presented herein, local internal storage  122  can be solid state drives (SSDs), while local, external storage  125  are hard disk drives (HDDs). It is appreciated that the presentation of local internal storage  122  separate from local external storage  125  within the present disclosure extends from the concept that certain types of non-volatile storage and particularly SSDs can be operated effectively while submerged in a fluid medium along with the processing components  150 , while other types of non-volatile storage, such as HDDs, may operate better if not submerged in a liquid medium. However, in one embodiment, the local internal storage  122  can also comprise or be solely HDDs, while the local external storage  125  can include SSDs. Also, in an alternate embodiment, information handling system  100  can include only local internal storage  122 , regardless of the type (i.e., SSD, HDD, etc.) of storage. As presented herein, the terminology “local external” indicates that the storage  125  is an integral part of the information handling system  100 , but connected via a data cable at a short distance from the processing components  150  (i.e., off the device chassis) rather than being directly connected on the device chassis via the system interconnect  115 . Also, in at least one embodiment, the local external storage  125  is located near enough to the main processing components  150  that there is minimal additional latency detected between accessing local internal storage  122  and accessing local external storage  125 . 
     In one embodiment, the non-volatile storage ( 122 / 125 ) provides storage of application programs, software, firmware, and one or more sets of data for use by processors  105  during one or more data processing operations. As shown, system memory  110  can include therein a plurality of modules, including firmware (F/W)  112 , basic input/output system (BIOS)  114 , operating system (O/S)  116 , and application(s)  118 . System memory  110  further includes one or more feedback control modules  170 . In one embodiment in which the immersion cooling tank is a self-controlled, intelligent device, program code of these feedback control modules  170  can be executed by processor  105  and can configure the information handling system  100  to control one or more operating features of the immersion cooling vessel and/or data center, as described in further detail herein. The various software and/or firmware modules  170  have varying functionality when their corresponding program code is executed by processor(s)  105  or other processing devices within IHS  100 . 
     Within the above description and throughout the disclosure, references to processing components refers to components that execute task sequences, while storage components refers to components utilized to secure either the input or output of a processing event. Both processing and storage are needed in increasing densities across the computer and server industry, in varying degrees. It is appreciated that in one or more embodiments, the term “processing” can be defined to be the holistic inclusion of task execution and storage thereof. 
     IHS  100  further includes one or more input/output (I/O) controllers  130  which support connection by, and processing of signals received from, one or more connected input device(s)  132 , such as a keyboard, mouse, touch screen, or microphone. I/O controllers  130  also support connection by, and forwarding of output signals to, one or more connected output devices  134 , such as a monitor or display device or audio speaker(s). Additionally, in one or more embodiments, one or more device interfaces  136 , such as an optical reader, a universal serial bus (USB), a card reader, Personal Computer Memory Card International Association (PCMCIA) slot, and/or a high-definition multimedia interface (HDMI), can be associated with IHS  100 . Device interface(s)  136  can be utilized to enable data to be read from or stored to corresponding removal storage device(s)  138 , such as a compact disk (CD), digital video disk (DVD), flash drive, or flash memory card. In one or more embodiments, device interface(s)  136  can also provide an integration point (e.g., a USB or serial port) for connecting other device(s), such as an external HDD, to IHS  100 . In such implementation, device interfaces  136  can further include General Purpose I/O interfaces such as I 2 C, SMBus, and peripheral component interconnect (PCI) buses. In the illustrative embodiment, each of input devices  132 , output devices  134 , and device interfaces  136  with removable storage devices  138  are illustrated as external to processing components  150 , while I/O controller(s)  130  reside within processing components  150 . 
     In one embodiment, IHS  100  includes a power controller  140 , which is coupled to a power distribution unit (PDU)  145  that is located externally to IHS  100 . PDU  145  provides a connection to the source of electrical power and power controller  140  provides and/or supports distribution of that electrical power within IHS  100  via a power distribution network (not shown). IHS  100  also comprises a network interface device (NID)  160 , which is also included within processing components  150 . NID  160  enables IHS  100  to communicate and/or interface with other devices, services, and components that are located external to IHS  100 . These devices, services, and components can interface with IHS  100  via an external network, such as example network  165 , using one or more communication protocols. Network  165  can be a local area network, wide area network, personal area network, and the like, and the connection to and/or between network  165  and IHS  100  can be wired or wireless or a combination thereof. For purposes of discussion, network  165  is indicated as a single collective component for simplicity. However, it is appreciated that network  165  can comprise one or more direct connections to other devices as well as a more complex set of interconnections as can exist within a wide area network, such as the Internet. 
     With reference now to  FIGS. 2 and 3 , there are presented schematic diagrams of respective information handling systems presented as two configurations of a server. First server  200  and second server  300  differ with respect to the location and connectivity of HDDs  125  relative to the server chassis. First server  200  and second server  300  (collectively referenced herein as server  200 / 300 ) include a casing  205  within which the majority of the functional components are assembled. The casing  205  is designed to be able to insertably fit within a server rack and allow connection to power cables and/or data cables and other connecting cables provided at or by the server rack. Casing  205  includes a pair of handles  207 / 307  for lifting and/or pulling server  200 / 300  when the entire server unit needs to be moved from one physical location to another or in order to insert and/or remove server  200 / 300  from a server rack (not shown). Located within casing  205  is a chassis or motherboard  210  on which is embedded or attached the various processing components of server  200 / 300 . As illustrated, these processing components include a plurality of processors (or processor integrated circuit chips)  105 , storage controller  215  and memory modules  220 . Server  200 / 300  can also include heat dissipation surfaces (i.e., heat sinks) co-located with the processing components. According to one aspect of the disclosure, one or more embodiments provide that heat generated and dissipated from the surface of the processors  105  and memory modules  220  are directly absorbed by a cooling fluid in which the processing components of server  200 / 300  is submerged during operation. Thus, server  200 / 300  can be designed without heat sinks, in one or more embodiments. Casing  205  is designed with a porous sidewall  225  having a plurality of holes and/or openings  230 ,  232 . Thus, server  200 / 300  can be a standard server that is designed for operation in an air environment (i.e., outside of a liquid-based immersion tank) such that the server components can be air-cooled. However, as described herein, aspects of the disclosure utilizes these holes and/or openings  230 ,  232  to allow for a cooling fluid to easily flow into and around the internal structure and/or components of server  200 / 300 . The cooling fluid can thus surround the various processing components that dissipate heat and directly absorb the dissipating heat by conduction and convection forces. These features are described in greater detail in the descriptions of  FIGS. 4-5 and 8 . 
     Server  200 / 300  are representative of any information handling system that can be partially or completely immersed or submerged in a cooling liquid to cool one or more of the functional components operating thereon. As one related aspect of being an immersible or submersible server, server  200 / 300  is shown oriented in an upright or vertical position, with the processing components at the bottom and the drive space  235  for housing HDDs  125  located at the top. Notably, server  200  does include on-chassis hard drive space(s)  235  within which HDDs  125  are located, as an integral part of the server  200 . In contrast, server  300  is shown having HDDs  125  external to and not an integral part of the server chassis  210 . As indicated by the dashed line representations of HDDs, one embodiment can allow for a standard server chassis  210  and casing  105 , wherein the HDDs  125  are removed and connected via cable  305  to allow for positioning above the server casing  205 , when second server  300  is in a liquid cooled environment. Notably, however, drive space  335  of second server  300  can accommodate a plurality of HDDs  125  to enable second server  300  to be reconfigured with HDDs  125  located within drive space  335  when second server  300  is being air cooled. 
     In the illustrated configuration, the HDDs are referred to as locally external HDDs. Thus, because second server  300  is designed for use within an immersion cooling tank, second server  300  is shown as being configured with locally external HDDs  125 , which are connected via cable  305  to second server  300 . Cable  305  can be a data cable, power cable, and/or a combination data and power cable. This configuration of second sever  300  allows for a local external connection of one or more HDDs, separate from the other processing components of the device in order to be able to submerge the processing devices in liquid for cooling thereof. The presented example of second server  300  illustrates that the location of the HDDs can be at a short distance away and apart from the chassis/motherboard  210  due to expected immersion of the chassis  210  within the immersion cooling liquid. It is appreciated that the configuration of second server  300  can also be different, given the lack of on-chassis HDDs. The chassis  210  can, in one embodiment, be more compact, eliminating the upper section  350  including the drive space  335  altogether. In at least one embodiment, the configuration of first server  200  can also be different from a conventional server, by extending the middle portion  240  of the chassis between the processing components and the drive spaces  235  to provide more separation of the HDDs  125  decreasing the likelihood of contact by the HDDs  125  with the cooling liquid. Other differences can also be provided to enable use of server  200 / 300  within an immersion cooling vessel. However, given the possibility of these various differences, the configuration and/or design of example servers  200 / 300  presented herein are not intended to imply or convey any limitation with respect to the actual configuration and/or layout and/or type of server that is ultimately provided as the immersion server that is cooled by submerging at least the processing components within a cooling liquid that is provided in an immersion cooling tank, as described herein.  FIGS. 22-25  and the descriptions thereof in Section I present a different configuration of immersion servers that are specifically designed to be liquid cooled, with integrated HDDs that are vapor cooled. However, for purposes of the general concepts of the disclosure, reference shall be made to server  200 / 300  to illustrate the application of the disclosed cooling concepts to existing server designs and configurations. 
     Further, it is appreciated that the specific designs and configurations of these servers ( 200 / 300 ) can in some instances affect the specific implementation of the immersion cooling vessel utilized and/or the immersion cooling features presented by the disclosure. However, the core concepts of immersion cooling apply to the various possible types of servers regardless of whether the servers include locally internal HDDs or locally external HDDs. 
     B. Immersion Cooling Tank Providing Cooling of Information Handling Systems with Two-Phase Vaporization-Condensation Cooling Cycle 
     Turning now to  FIGS. 4 and 5 , there are presented an internal view of two different examples of immersion cooling tanks  400  and  500 , respectively designed for insertion of first server  200  and second server  300 . It is appreciated that the internal views provided of immersion cooling tank  200 ,  300  are transverse views running in the lateral direction of the illustrated server  200 / 300 , such that the side of the server chassis is shown (without functional components). A lateral view running parallel to the direction of server  200 / 300  is presented by  FIG. 8 . Again, because of the similarities in the figures, the descriptions are presented together with associated similar reference numerals separated by commas and/or a slash. 
     Each immersion cooling tank  400 / 500  operates as a two-phase vaporization-condensation cooling vessel for cooling one or more information handling systems and in particular server  200 / 300  according to the various methodologies described hereinafter. Immersion cooling tank  400 / 500  includes an enclosure  405  having an exterior casing with an interior lower volume  402  within which cooling liquid  412  can be maintained and heated to a boiling point temperature. The cooling liquid  412  is generally located in the volume extending between the bottom of the enclosure  405  of cooling tank  400 / 500  up to the liquid surface  420 , i.e., the topmost layer/level of cooling liquid  412 . The interior of enclosure  405  also includes an upper volume  404  extending from the liquid surface  420  up to a tank cover  480 . In the illustrative embodiments, tank cover  480  includes a handle  485  to allow for opening of the tank cover  480 . 
     Also, according to one aspect, each immersion cooling tank  400 / 500  includes a server rack  410 / 510  (illustrated with a side rail and a base structure), which can be generally incorporated or placed within the sidewalls and base of the lower volume  402  of the tank enclosure  405 , with at least one section extending below the liquid surface  420  of immersion cooling liquid  412 . Within the lower volume  402  is shown a base portion and opposing side rails of the server rack  410 / 510 . Server rack  410 / 510  can respectively provide support for holding server  200 / 300  in place while server  200 / 300  is submerged in cooling liquid  412 . In one embodiment, server rack  410 / 510  is built into immersion cooling tank  400 / 500  or permanently attached to the interior sides of the side and/or bottom panels of casing  405 / 505 . Server rack  410 / 510  can also be separate from and placed into the existing immersion cooling tank  400 / 500  following construction of the immersion cooling tank  400 / 500 . Positioned within each server rack  410 / 510  is respective server  200 / 300  which are shown extending laterally across immersion cooling tank  400 / 500  from the first side rail (located on the left) to the opposing second side rail (located on the right). 
     Immersion server  200  is illustrated partially submerged below the liquid surface  420 , with the section of the chassis holding the HDDs  125  above the liquid surface  420  of the cooling liquid. In contrast, immersion server  300  is illustrated with the chassis fully submerged below the liquid surface  420 , with the locally external HDDs  125  above the liquid surface  420  of the cooling liquid  412 . In this version of immersion cooling tank  500 , immersion server  300  can include handles  307  extending from the cooling liquid  412  to allow for removal of the immersion cooling server  300  from the cooling liquid  412 . The extension of handles  307  above the liquid surface  420  enables server  300  to be pulled up out of the cooling liquid without contacting the cooling liquid  412 . In one or more embodiments, one or both of casing  405  and handles  207 / 307  of respective server  200 / 300  can be elongated to extend above the surface level  420  of cooling liquid  412  within immersion cooling tank  400 / 500 . Alternatively, the level of cooling liquid  412  can be measured such that only the heat-dissipating components on server  200  that are to be liquid cooled are immersed in cooling liquid  412 . 
     According to one embodiment, extending from casing  405  of immersion cooling tank  400 / 500  is a pipe connector  495  with an associated shutoff or flow control valve  497 . One or more of the functionality or use of these components are described in Section G, which is provided below. As its simplest function, pipe connector  495  and flow control valve  497  enable cooling liquid  412  to be drained from immersion cooling tank  400 / 500 , in order to facilitate tank maintenance, for example. 
     As shown in the figures, the HDDs  125  are located within a middle portion (or volume) of the immersion cooling tank  400 / 500  in which a plume of vapor is shown rising from the surface of the cooling liquid. This aspect of the design of the immersion cooling tank  400 / 500  and respective servers  200 / 300  will be described in greater detail in the following Section C. 
     The upper volume of the enclosure  405  includes at least one condenser  460 , which as provided by the inset includes a condensation surface  465  and pipes  467  in which condensation fluid flows. The condensation fluid is maintained at a temperature that is lower than the condensation temperature of the rising vapor  422 . At the condenser  460 , the rising vapor  422  is condensed back to cooling liquid or condensate  462  by releasing latent heat to the condenser as the rising vapor  422  comes into contact with the condensation tubes or surface in which the condensation liquid flows. The condensation of the rising vapor  422  occurs as the flowing, cooler condensation fluid within the condenser absorbs the heat energy from the rising vapor  422 , causing the rising vapor  422  to convert (i.e., undergo a phase change) from gas to liquid phase. The resulting converted/condensed cooling liquid  462  is then returned back to the lower volume of cooling liquid  412  in the bottom of the enclosure  405 . In one embodiment, a cooling liquid return system  440  is provided below the condensers to catch the falling liquid condensate  462  in order to prevent the falling condensate  462  from coming into contact with the HDDs  125  located below the condenser  460 . In at least one embodiment, as illustrated by  FIG. 5 , the condensate  462  is channeled via a secondary conduit  545 . 
     In one embodiment, the condensed cooling liquid collection system  440  collects the condensed liquid as the liquid drops from the condensation surface  465 , due to gravity, following condensation of the rising vapor  422 . According to the illustrated embodiment, the condensation surface  465  is angled to at least one side relative to a horizontal plane to cause the condensate  462  generated from the condensation of the rising vapor  422  to flow off towards at least condensed cooling liquid collection system  440 . 
     The condensation fluid (not shown) flows within the tubes/pipes close to the condensation surface  465  and maintains the condensation surface  465  at a lower temperature than a condensation point of the rising vapor  422 . According to one or more embodiments, the condenser  460  and in particular the condensation surface  465  comprises at least one length of tubular piping extending from an external connection point running to the inside of the enclosure  405  and then back to the outside of the enclosure  405 . The external surface of the tubular piping can, in one embodiment, provide the condensation surface  465 , and the condensation fluid flows through the interior bore of the tubular pipe from an external fluid source/reservoir. 
     Indicated below liquid surface  420  in the lower volume  402  of enclosure  405  is a power distribution unit (PDU)  425  sitting atop a platform  430 . This platform  430  can be simply a ledge or space at which PDU  425  can be nested. Alternatively, the platform  430  can be one specifically designed within immersion cooling tank  400  or as a part of server rack  410 / 510 . PDU  425  is coupled via a power cable  470  to the external power source  475  located on the outside of immersion cooling tank  400 / 500 . PDU  425  provides electrical power to server  200 / 300  as well as other electronic devices within immersion cooling tank  400 / 500 , of which HDDs  125  is illustrated. HDDs  125  is shown located above liquid surface  420  on a platform  445 , which can be porous (air accessible) in one embodiment. A first power connector  427  is shown extending from PDU  425  to server  200 / 300 , while a second power connector  528  extends to HDDs  125 . In  FIG. 5 , communication and data cable  305  is also shown connecting HDD  125  to server  300  to enable data transfer between server  300  and the HDD  125  during operation of both the server  300  and HDD  125  within immersion cooling tank  500 . 
     Within immersion cooling tank  400 / 500 , immersion server  200 / 300  is connected via a number of connectors  415  indicated at the bottom of server rack  410 / 510 . These connectors  415  allow servers  200 / 300  to be insertably coupled to the server rack  410 / 510 . The connectors  415  are coupled to or are extensions of a network cable bundle  450  which enables immersion server  200 / 300  to communicate with other devices both within and outside of immersion cooling tank  400 / 500 . In alternate embodiments, the communication and data cables of network cable bundle  450  can be connected within the enclosure  405  by running the cable bundle  450  through a trunking or sealed space (not expressly shown) that is provided within the enclosure  405 , such as within the enclosure walls. The cable bundle  450  is then connected to the backs of the server(s)  200 / 300  via specific rack connectors  415 . 
     For connections to endpoints outside of the enclosure  405 , immersion cooling tank  400 / 500  includes network cable bundle  450  and power cable  470 , which extend through a side wall of enclosure  405  into the exterior space outside the tank  400 / 500 . To support the interconnection of multiple server racks, for example, a large number of network cables are required to access the immersion cooling tank  400 / 500 . These cables require an opening to access the enclosure  405 , and the size and number of openings can significantly increase the opportunity for loss of cooling fluid to the outside of the tank  400 / 500 . Thus, communication in and out of the immersion tank  400 / 500  requires a design that enables the communication and data cables of network cable bundle  450  to enter the immersion cooling tank  400 / 500  without providing any seams through which the immersion fluid can escape. Similarly, the design must allow for the power cable  470  to be run into the tank  400 / 500  from the outside in order to provide power to the devices inside of the tank  400 / 500 , without allowing for escape of the cooling fluid. This aspect of the disclosure thus provides a robust solution to seal the openings created by the numerous cables and any other openings that may be required within the side walls or cover of the immersion cooling tank  400 / 500 . 
     In order to support the extension of network cable bundle  450  and power cable  470  from the outside of immersion cooling tank  400 / 500  to the inside, and vice versa, one aspect of the disclosure provides a rubber-based grommet  455  that operates to seal the areas at which the respective cables enter and/or exit the wall of the cooling tank  400 / 500 . The rubber grommet  455  fits tightly around Cat 6 or fiber cables and power cables, and the rubber grommet  455  is then inserted into an opening in the wall of the immersion cooling tank  400 / 500 . Once inserted into the opening, the rubber grommet  455  maintains a tight seal around the cables and the perimeter of the opening and prevents escape of vapor from inside the tank to the outside air and vice versa. This capability of preventing escape of the cooling fluid is an important aspect of the immersion tank  400 / 500  design. 
       FIG. 6  presents various different views of the configuration of the grommets  455 .  FIG. 6  also illustrates the use of the grommets  455  with multiple cables, representing network cable bundle  450 , extending through the wall of the immersion cooling tank  400 / 500 . An exterior and an interior view of the two interlocking sides of a single grommet  455  are shown by  FIGS. 6A-6B . According to one aspect of the disclosure, and as illustrated by  FIGS. 6C-6E , immersion cooling tank  400 / 500  is configured with one or more grommets  455  placed in both the internal and external surface of one or more of the walls  605  of the enclosure  405  ( FIG. 4 ) to create a seal through which communication and data cables of network cable bundle  450  and power cables  470  can be introduced into the enclosure  405  from the outside.  FIG. 6C  shows the stacking of a plurality of grommets  455  inserted into the wall  605  of enclosure  405  and extending out of the interior wall surface  615 .  FIG. 6D  then illustrates network cable bundle  450  extending through the grommet  455  at the exterior wall surface  610  of the enclosure  405 , while  FIG. 6E  illustrates network cable bundle  450  extending through the grommet  455  at the interior wall surface  615  of the enclosure  405 . According to the illustrated embodiment, the network cable bundle  450  represents  64  infiniband connectors. However, it is appreciated that the use of grommets  455  can be applied with other types of network and power cabling. Importantly, the configuration of the grommet  455  and the material utilized to construct the grommet  455  allows the various cables to be introduced into the enclosure  605  without causing leakage of either the cooling liquid  412  or the vapor  422  to the outside of the enclosure  605 . These special rubber-based grommets  455  are utilized to enclose the point(s) of penetration into the tank from the outside to prevent (1) leakage of the dielectric fluid and/or (2) leakage of the high pressure vapor above the liquid surface of the enclosure. 
     Thus, grommet  455  has specific qualities that enable the cables&#39; accesses to be sealed to prevent both liquid and/or vapor from escaping to the outside of enclosure  405 . Generally, the selection of the grommet material requires consideration of (1) the qualities of the material that makes it flexible enough for use but not prone to allow for leakage of liquid or vapor, even under high pressure, (2) durability of the material under constant heat conditions, (3) the specific cooling fluid being utilized within the immersion tank, not having any negative interactive properties with the grommet material, and (4) other criteria that can be relevant to the system designer. According to one or more embodiments, butyl rubber exhibits each of the above characteristics and is thus provided as the immersion grommet  455  in example immersion cooling tanks  400 / 500  as well as the other immersion cooling vessels described hereinafter. 
     In one or more embodiments, the dielectric liquid  412  utilized as the cooling liquid is Novec fluid, which has limited reactive properties with butyl rubber. Thus, the utilization of the butyl rubber grommet  455  provides a solution that maintains flexibility while in contact with the Novec vapor. The use of the butyl rubber provides a rubber grommet  455  that fits tightly around the cables, e.g., Cat6 or fiber cable (see  600 D- 600 E). And, the rubber grommet  455  maintains a tight seal between the vapor inside the enclosure  405  and the outside of the enclosure  405 . This aspect of the disclosure thus provides a robust solution to seal the openings required to run the numerous network and other cables. Additionally, utilization of the grommet  455  enables and/or facilitates future upgrades and cable replacement throughout the working life of the enclosure  405 , without having to glue or epoxy the cables into the tank. 
     According to one aspect of the disclosure, immersion cooling tank  400 / 500  includes a dielectric cooling liquid  412  that is selected based on the fluid exhibiting certain desirable characteristics with respect to its high volatility (low boiling point temperature) when exposed to surface heat dissipating from an operating server  200  and its low condensation barrier from vapor to liquid when exposed to room temperature condensation liquid, such as water. In one or more of the described embodiments, the dielectric cooling fluid is Novec 649, a product of 3M®. Novec 649 is a dielectric fluid that boils at 49 degrees Celsius. More importantly, the Novec fluid does not conduct electricity and/or does not react or interact with surrounding components when exposed to electricity or electrical components. Another benefit to the use of Novec fluid is its superior functioning during servicing of components. During servicing of a server, for example, once the server is pulled out of the fluid and left to sit for a few seconds, the high volatility of the fluid causes the Novec 649 fluid to evaporate leaving a dry surface of the server to work on. 
     As one aspect of the disclosure, and with the use of Novec liquid as the cooling liquid, the condensation fluid can be surface water at room temperature. As introduced above, Novec liquid is highly volatile and has a boiling point temperature of 49 degrees Celcius. Thus, from experimentation it has been shown that a single server operating minimal processes dissipates sufficient heat to raise the temperature of the Novec liquid to its boiling point temperature, resulting in vaporization of a portion of the liquid. With such a low boiling point, the threshold for cooling the vapor to its condensation point is relatively low. Thus, within one or more embodiments, water provide at room temperature can be utilized as the condensation fluid. Because the boiling point of water is not achieved until the water is heated to 100 degrees Celsius, water, when utilized as the condensation liquid, provides a vast amount of heat absorption capacity to condense the rising Novec vapor. Additionally, water has a high specific heat and relatively high thermal diffusivity when compared to other liquids, making water an ideal candidate for use as the condensation liquid. Further, there is an abundant supply of water and water is relatively inexpensive as a condensation liquid. 
     According to one aspect of the disclosure, the dielectric vapor rises and the condensed cooling liquid falls due to relative density and operation of gravity. Thus, the cooling of the electrical components can have system or server power usage effectiveness (SPUE) of 1.00. SPUE refers to the ratio of total amount of power used by the data center facility to the power delivered to the IT equipment. 
     As a next benefit, the implementation of the immersion cooling tank provides an opportunity to increase the density of IT gear in a server rack (tank). When servers  200 / 300  are operated within immersion cooling tank  400 / 500 , there is no longer the need for large, space consuming heat sinks, as the dielectric fluid boils directly off the processor chip. Thus, the server and/or rack space or volume that was once used for fans or heat sinks for the server module can now be filled with useful functional components, such as other processors. 
     As yet another benefit, the dielectric fluid provides large thermal capability, as the thermal capability of the dielectric fluid is significant. Thus, the components in the dielectric fluid can operate well below the thermal limits. Thus, a conventional server system which would only support low wattage processors due to the limited volume available for heat sinks can now support high end processors. 
     Finally, with the implementation of the immersion cooling tank  400 / 500 , there is no longer a need for expensive data center cooling equipment. The immersion tank is a sealed unit and because all dissipated heat is eventually absorbed and transmitted away from the enclosure by the condensation fluid, there is also no need to cool the room around the tank. Also, the immersion tank can operate in almost any environment and does not require an air-conditioned or heated space. 
     C. Vapor Cooling of HDDs within Immersion Cooling Tank 
     One consideration that is relevant to the described innovation includes an appreciation of the limitations of operating HDDs within a liquid environment, such as an immersion-based cooling system for datacenter servers, as presented herein. Conventional HDDs are designed with a lubricated rotating spindle which needs to be free from obstruction while spinning in order to operate effectively and enable a longer lifespan of the HDD. As determined by practical observation and testing, engineering analyses, and/or extrapolation of known theories in physics and other sciences, submerging a HDD in a liquid filled enclosure does not properly accommodate cooling needs of rotating HDDs by virtue of parasitic friction that is induced when liquid enters the HDD motor/spindle region. This entering liquid (a) dissolves lubricant used on the spindle over time and (b) increases the amount of friction on the moving parts, thus causing increased wear and tear, which results in shorter lifecycles of the HDDs. Additionally, the above effects also increase the need for frequent maintenance of the HDDs, which negatively affects the equilibrium achieved and/or desired within an operating immersion cooling system. 
     Notably, to address this limitation with HDDs utilized with immersion-based datacenters, a conventional solution would include utilizing remote storage racks that would be in a different physical location. These remote storage racks then require a fan-based cooling infrastructure, typically involving additional space, and use of large number of fans powered by an external power source. This solution also requires large amounts of cabling from the data center to the remote storage location, which along with the increased power consumption, significantly increases the expense of running and/or cooling the data center and storage facility. Another conventional solution involves expensive HDD encapsulation with epoxy to prevent liquid from entering the internal structure of the HDD. Among the problems and/or disadvantages with this approach are: (1) the approach is relatively expensive, as the epoxy is costly and the process requires additional amounts of man/machine hours; (2) the epoxy encapsulation is permanent, thus preventing any future maintenance on the device; (3) epoxy encapsulation voids the HDD manufacturer&#39;s warranty; and (4) the encapsulation in epoxy increases the dimensions of the resulting encapsulated HDD, which makes the encapsulated HDD difficult to fit into the standard HDD carriers (such as drive space  235  (See  FIG. 2 )). 
     One aspect of the described embodiments thus presents a method and system to effectively deploy an immersion based solution for a server that utilizes rotating HDDs, while accommodating the cooling needs of rotating HDDs, without the additional expenses and other limitations and/or problems inherent with the above conventional approaches. It is also appreciated that the implementation of this configuration of servers enables development and deployment of ultra-dense liquid cooled servers as the HDDs do not have to be accommodated on the server chassis. 
     The example immersion cooling tanks  400 / 500  of  FIGS. 4 and 5  represents two-phase heat transfer HDD cooling system that operates as a vapor-based cooling system for HDDs, according to one or more embodiments. As provided by  FIG. 5 , the interior of enclosure  405  also includes a HDD cooling area  525  in which at least one HDD  125  can be placed during operation of the HDDs  125 . The HDD cooling area  525  is located at a first distance above the liquid surface  420  within enclosure  405  and is in a direct path of plumes of vapor  422  rising off the liquid surface  420 . Thus, the above introduced immersion cooling tank  400 / 500  provides techniques for cooling hard disk drives (HDDs) within an immersion cooling environment without having to directly immerse the HDDs within the cooling liquid medium. This technique involves placing the HDDs in the path of a rapid flow of rising vapor generated by boiling of a highly volatile fluid in a cyclical multiphase (i.e., two-phase vaporization-condensation) heat transfer enclosure or vessel, such as an immersion cooling tank  400 / 500 . The two phase (vaporization-condensation) tank  400 / 500  is configured with a liquid immersion system that boils the cooling liquid  412  within a bottom enclosure or reservoir and creates vapor plumes  422 . The vapor plumes  422  are driven by density gradients through a HDD cooling area  525  located above the cooling liquid  412  within the tank  400 / 500 . As the vapor  422  rises, the vapor  422  passes with an upward velocity over the exposed surface of the HDDs  125  located within the HDD cooling area  425 / 525  and the vapor  422  flows across the exposed heated surface area of the HDDs  125 . The movement of the cooler vapor  422  across and away from the surface of the HDDs  125  causes the rising vapor  422  to absorb some of the heat being dissipated from the surface of the HDDs  125  as well as ambient heat generated by the HDDs  125  within the HDD cooling area  425 / 525 . Thus, the vapor  422  cools the HDDs  125  while in transit to an upper condenser  460 . 
     At the upper condenser  460 , the vapor  422  is condensed back to liquid condensate  462  by coming into contact with the condensation surface or condensation pipes/tubes in which the condensation liquid flows. The condensation of the rising vapor  422  occurs as the cooler condensation fluid flowing within the condenser  460  absorbs the heat energy from the vapor  422 , causing the vapor  422  to convert (i.e., undergo a phase change) from gas to liquid phase. The resulting cooling liquid condensate  462  is then channeled via a secondary conduit  545  back to the cooling liquid reservoir in the bottom of the enclosure  405  to avoid the liquid condensate  462  coming into contact with the HDDs  125 . According to one or more embodiments, as illustrated by  FIG. 5 , the HDD cooling area  525  includes a rigid, mesh type structure extended across one segment of the inner perimeter of the enclosure above the liquid surface  420  to form a porous platform  542  on which the one or more HDDs  125  are placed. The platform is porous to allow the rising vapor  422  to pass through the HDD cooling area  525  up towards the upper condenser  460 . In at least one embodiment, the HDDs  125  can be spaced apart from each other and can be oriented within the HDD cooling area  525  to maximize the amount of exposed surface that will come into contact with the flow of rising vapor  422 . In a second embodiment with locally external HDDs, the HDD cooling area  525  includes a series of holding clips and/or sleeves designed to hold or support one or more of the HDDs  125 . The HDDs  125  are then suspended (i.e., held in place) within the HDD cooling area  525  based on the location and/or configuration of the specific mechanism being utilized to hold the HDDs  125 . It is appreciated that other embodiments are possible in addition to those described herein, without limitation. According to one or more of the described embodiments, the liquid that is utilized to produce the cooling via vaporization and condensation within the enclosure is a dielectric fluid. Selection of a dielectric fluid allows for the avoidance of any electrical interaction of the components being cooled with the fluid and/or rising vapor, among other benefits. 
     The HDD cooling system includes a heat source or heat dissipating component that dissipates heat into the lower volume  402  of the enclosure  405 . Within the presented examples, the heat dissipating component is represented as a server  200 / 300 . However, it is appreciated that many other types of heat dissipating components that can benefit from liquid cooling by immersion within the liquid as well as a generic heat source utilized solely to heat the cooling liquid to a boiling point can be utilized in place of or in addition to server  200 / 300  within the HDD cooling system. According to one aspect of the disclosure, regardless of the type of heat source or heat dissipating components utilized/provided, the amount of heat dissipated is sufficient to heat the cooling liquid  412  within the lower volume  402  to a boiling point temperature at which at least a portion of the cooling liquid  412  evaporates, generating a plume of rising vapor  422 . The plume of rising vapor  422  flows/moves rapidly upwards through the HDD cooling area  525  and across one or more surfaces of the at least one HDD  125 . The moving vapor  422  cools the at least one HDD  125  via convection as the vapor  422  comes into contact with and moves across the one or more surfaces of the at least one HDD  125 . 
     As introduced above, the HDDs  125  can be communicatively coupled to one or more processing components that are either internal to the enclosure  405  or external to the enclosure  405 . According to one aspect, the HDDs  125  can be respectively connected to externally and/or internally supported server(s) via cables of network cable bundle  450  or HDD connecting cable  305  ( FIG. 3 ). It is appreciated that these connectors ( 450 / 305 ) are rated to operate at temperatures equal to or exceeding a maximum temperature from among the higher of (a) an ambient exterior temperature of the HDDs  125  within the HDD cooling area  525  and (b) the temperature of the rising vapor  422  and/or the boiling point temperature of the cooling liquid  412 . 
     According to the described embodiments, server  200 / 300  represents the heat dissipating component that dissipates heat into the lower volume of the enclosure  405  while the server is operating. One aspect of the disclosure provides that the amount of heat dissipated by server  200 / 300  is sufficient to heat the cooling liquid  412  within the lower volume  402  to a boiling point temperature at which at least a portion of the cooling liquid  412  evaporates, generating a mass or plume of rising vapor  422 . The plume of rising vapor  422 , indicated by the vertical arrows, flows/moves rapidly upwards through the upper volume towards condenser  460 . According to one embodiment, the upper volume includes a HDD cooling area  525  (generally including a platform or other holding structure) in which at least one HDD  125  can be placed during operation of the HDDs. The plume of rapidly rising vapor  422  moves through the HDD cooling area and across one or more surfaces of the at least one HDD  125 . The rapidly moving vapor  422  cools the HDD  125  via convection as the vapor  422  comes into contact with and moves across one or more surfaces of the at least one HDD  125 . 
     According to one embodiment, the plume of vapor  422  are driven by density gradients through the HDD cooling area located above the cooling liquid  412  within the tank  400 / 500 . As the vapor rises, the vapor passes through the HDDs located within the enclosure with an upward velocity and flows across the exposed hot surface area of the HDDs. It is appreciated that the presence of a HDD cooling area is an optional enhancement that is not necessarily provided in different embodiments of the immersion cooling tank  400 / 500 . 
     In addition to the described components which relate to the vaporization and resulting cooling aspects of the cooling system, the upper volume  404  of the enclosure  405  of cooling system also includes: a condenser  460  above both the HDD cooling area  525  and the at least one HDD  125 ; and a cooling liquid collection and/or return system ( 440 / 545 ), a portion of which is located above the HDD cooling area  525 . In one or more embodiments, illustrated in greater detail in  FIG. 5 , the cooling liquid return system comprises condensed cooling liquid (condensate) collection system  440  located above the HDDs  125  and a condensate return conduit (or channel)  545 . In one embodiment, the condensate return channel  545  is provided close to the perimeter of the upper volume  404  of the enclosure  405 , although the exact placement can vary by design. The condensate collection system  545  is located above the at least one HDD  125  so as to protect the HDDs  125  from having any of the condensed cooling liquid condensate  462  fall on the operating HDDs  125 . The condensate collection system  440  collects the condensed liquid as the liquid drops from the condensation surface  565 , due to gravity, following condensation of the rising vapor  422 . The condensate return channel  545  provides a conduit which extends from the condensate collection system  440  to below the HDD cooling area  525  into the lower volume  402  of the enclosure  405 , returning the condensate  462  to the lower volume of the enclosure  505 , while avoiding contact between the condensate  462  and the at least one HDD  125 . 
     According to the illustrated embodiment, the condensation surface of the condenser  460  is angled to at least one side relative to a horizontal plane to cause the condensate  462  that is generated from the condensation of the rising vapor  422  to run off towards the perimeter of the enclosure  405  away from the HDDs  125  and towards condensate collection system  440 . The condensate collection system  440  is also angled to allow the collected condensate to run off towards condensate return conduit  545  that directs the collected condensate  462  towards the lower volume of cooling liquid  412 , without allowing the condensate  462  to come into contact with the at least one HDDs  125 . 
     While the above described embodiment provides for the condensate return system preventing the condensate from coming into contact with the HDDs, at least one alternate embodiment is provided in which the HDDs  125  can be “drip” tolerant. Thus, for example, the HDDs may have an exterior casing that allows the HDDs to deflect dripping condensate without negatively affecting the operation of the HDDs. Thus, with these alternate embodiments, the HDD cooling system can be configured without a bypass system for the condensate, and which allows some dripping of the condensate on the HDDs. Additionally, in one more embodiments, the HDDs can be hermetically sealed, which would allow the HDDs to be fully or partially immersed while operating. It is appreciated, that even with such HDDs, the aspects of the disclosure allowing for the cooling of these immersible HDDs by rising vapor can still be valuable given the very high cost of the cooling fluid (i.e., Novec fluid). Vapor cooling of the HDDs enables savings on the total cooling liquid volume required at installation. With these types of HDDs, as well, one implementation can provide that the HDDs are only partially immersed so that the HDDs are cooled by a combination of liquid cooling and vapor momentum cooling. 
       FIG. 7  is a flow chart illustrating one example of a method by which an immersion tank system can be implemented and utilized to provide cooling for HDDs by producing a high velocity vapor flow across a HDD cooling area within a heat-dissipating system, such as an immersion cooling tank  400 / 500 , in accordance with one embodiment. Aspects of the flow chart can be implemented with reference to one or more components described within any one of the different embodiments of a vapor cooling system for HDDs as presented in  FIGS. 4-5 . Method  700  also includes one or more feedback control operations that can be performed during the cooling of the HDDs  125 . The method  700  begins at block  702  at which the cooling liquid is inserted into the lower volume  402  of the immersion cooling tank  400 / 500 . The method  700  then includes submerging the processing devices (e.g., server processor and memory modules) into the cooling liquid (block  704 ). At block  706 , method  700  provides placing the at least one HDD within a HDD cooling area  525  of the immersion cooling tank  500 . As stated above, the immersion cooling tank is configured with a lower volume having a cooling liquid and a processing device submerged within the cooling liquid and which device dissipates heat sufficient to raise the temperature of the cooling liquid to a boiling point temperature and cause vaporization of a portion of the cooling liquid to generate a plume of rising vapor  422 . The immersion cooling tank  400  is further configured with an upper volume  404  in which the HDD cooling area  525 , at least one condenser  460 , and a liquid collection and/or return system  440 / 545  are located. The HDD cooling area  525  is located at a first distance above a surface layer of the cooling liquid  412  within the lower volume and in a direct path of the rising vapor  422 . The HDD cooling area  525  provides an area at which the at least one HDD  125  can be cooled during functional operation of the at least one HDD  125 . The at least one condenser  460  is located at a second distance that is above both the HDD cooling area  525  and the at least one HDD  125 . The condenser  460  includes a condensation fluid that flows proximate to the surface of the condenser surface and which maintains the condenser  460  at a lower temperature than a condensation point of the rising vapor  422 . A substantial portion of the rising vapor  422  that passes through the HDD cooling area  525  and cools the at least one HDD  125  is condensed back into liquid phase on contact with or exposure to the condenser  460 . 
     The method  700  further comprises applying power to and/or activating/initiating the operation of the submerged processing device to cause the processing device to execute one or more program instructions (block  708 ). The processing device&#39;s execution of program instructions causes the processing device to generate heat sufficient to cause the cooling liquid to boil and vaporization of the cooling liquid to occur. The vaporization of the cooling liquid results in generation of a rising vapor, sufficient to cool the HDDs. 
     Method  700  then includes monitoring, via one or more electronic sensors and/or feedback devices, the operating conditions of the immersion cooling tank  400 / 500  (block  710 ). Without limitation on the disclosure and according to one or more embodiments, among the feedback and/or control devices and systems that can be provided within example immersion cooling tanks  400 ,  500  are: pressure sensors  540  and associated feedback control system, a fluid level sensor  535  and associated feedback control system, and a condensation fluid leakage detection system, which includes conductivity strip  530  ( FIG. 5 ).  FIG. 18  (which is further described in later sections) generally shows a second embodiment of a rack-based immersion cooling tank  1800  configured with a plurality of additional sensors and feedback and/or control devices. With the exception of the pressure regulating system described within Section H, the mechanisms and methodologies utilized to provide the various system controls are only generally provided for herein. However, it is appreciated that these aspects of the disclosure involve techniques related to general autonomic real-time control mechanisms and/or methodologies that provide for the proper operation and maintenance of the entire immersion cooling system. These control mechanisms/methodologies include several detection mechanisms/devices and functional control loops to enable features such as, but not limited to, controlling the immersion fluid level, detecting leaks in the condenser, detecting and controlling to differential pressure and other pressure conditions, detecting or responding to other conditions within the tank, and providing automatic power shutoff and/or transmitting notification to administrator or IT personnel, in response to certain detected conditions. One or more of the responses to a detected condition can be implemented by processor execution of code associated with one or more feedback control module(s)  170  ( FIG. 1 ). 
     Returning to the flow chart, at decision block  712 , method  700  determines whether there are any conditions detected that require system maintenance or a control response. When no such condition exists, method  700  loops back to block  710  where the sensors continue to monitor for the occurrence of one or more conditions. However, in response to there being a condition detected requiring system maintenance or a control response, method  700  includes mechanically, programmatically, or electronically performing one or more corresponding control operations to maintain an equilibrium or proper operating state of the immersion cooling tank  400 / 500  (block  714 ). With respect to the vapor cooling of the HDDs  125 , operating conditions of interest include, but are not limited to: (1) the amount of cooling being provided by the rising vapor, which can be controlled by throttling or increasing the amount of processing being performed by the processing devices, which correlates to the amount of rising vapor generated; (2) the amount of heat being dissipated by the HDDs relative to the cooling being provided by the rising vapor, where a rate of data access to the HDD can be controlled (e.g., throttled) if the HDDs are not being sufficiently cooled by the rising vapor; and (3) the highest level of the cooling liquid within the lower volume relative to the HDD cooling area, where the cooling liquid is required to remain below the HDD cooling area to avoid contact with the HDDs. 
     It is appreciated that operation of at least one processing device or server results in heat dissipation into the surrounding cooling liquid, which absorbs sufficient heat to cause the cooling liquid to reach the boiling point and result in vaporization of some of the cooling liquid to create rising vapor. According to one embodiment, method  700  further includes monitoring via a set of electronic and mechanical sensors and feedback devices one or more operating conditions (e.g., as pressure, temperature, liquid level, etc.) within the immersion tank (block  710 ). 
     D. Method to Protect PDUs from Water Infiltration and Enhance PDU Efficiency by Immersion in a Dielectric Liquid 
     With the above described immersion cooling tank  400 / 500  operating as a cyclical heat exchange ecosystem, which is sealed to prevent loss of cooling fluid to the outside, one important consideration is the need to provide power to the plurality of servers  200 / 300  and other electronic devices (e.g., HDDs  125 ) operating within the immersion cooling tank  400 / 500 . 
     According to one or more of the described embodiments, the cooling liquid that is utilized to produce the cooling via vaporization and later condensation within the enclosure is a dielectric fluid. Selection of a dielectric fluid allows for the avoidance of any electrical interaction of the components being cooled with the fluid and/or rising vapor, among other benefits. For cost and other considerations, water can be utilized as the condensation fluid. Given this use of a non-dielectric condensation fluid, such as water, additional considerations also have to be given to the fact that water is conductive and that there is a risk of leaks of the condensation fluid within the tank. Such a leak could cause water to come into contact with an exposed power distribution unit (PDU), which can cause electrical arcing and other potentially damaging and/or dangerous conditions within the tank. Because water is conductive, the proximity of the water to high voltage equipment creates UL (electrical standards board) safety concerns. Also, with water being utilized as the condensation liquid, the submerged PDU is protected from the water spillage in the event of a leak in one of the overhead condenser units. This is because the water, which is less dense than the dielectric cooling fluid, will simply float on top of the dielectric cooling fluid, without coming into contact with the PDU. 
     Thus, according to one aspect of the disclosure, rather than de-localizing either the condensation process or the power distribution units from being local to the immersion cooling tank  400 / 500  or to each other, or require that the condensation liquid be a non-conductive fluid, which is significantly more expensive than the use of water and provides less heat absorption capacity, aspects of the present disclosure provides a solution that yields additional benefits to the implementation of example immersion cooling tank  400 / 500 . To further describe this implementation, reference is made to  FIGS. 4 and 5  and later to  FIG. 8 . This aspect of the disclosure provides techniques to prevent electrical arcing and/or other problems otherwise inherent if a non-dielectric condensation fluid falls on the power distribution units within the immersion tank. Additionally, this aspect yields several benefits associated with power efficiency, as detailed herein. 
     Referring to  FIGS. 4 and 5 , in order to provide the required electrical power, the immersion cooling tank  400 / 500  also includes power distribution units (PDUs)  425 . As shown by  FIGS. 4 and 5 , PDUs  425  are submerged below the surface  420  of the cooling liquid  412 . Providing power to the submerged PDUs  425  are power cables  470 , which extend through the walls of immersion cooling tank  400 / 500  for connection to example external power source  475 . PDUs  425  can provide electrical power to the various electronic devices and/or components within immersion cooling tank  400 / 500  via power connectors (e.g.,  427 ). As described herein, servers  200 / 300  represent electronic devices and/or components that are submerged below the surface  420  of the dielectric cooling liquid  412 , and HDDs  125  represent electronic components and/or devices that are located within the tank volume, above the surface  420  of the dielectric cooling liquid  412 . 
     Immersion tank  400 / 500  also comprises at least one condenser  460  (and potentially multiple condenser sub-units, as illustrated and described below with respect to  FIG. 8 ) located above the surface  420  of the dielectric cooling liquid  412 . Condensation fluid (not shown) flows in liquid form through the condenser  460  during normal operation of the immersion cooling tank  400 / 500 . Within the various described embodiments, the condensation fluid (or liquid) is less dense (i.e., has a lower density) than the selected dielectric cooling fluid. Leakage of the condensation fluid into the lower tank volume  402  results in the lighter condensation fluid floating atop the surface  420  of the heavier dielectric cooling liquid  412 . The leaked condensation fluid would thus not come into contact with the PDUs  425 , as the PDUs  425  are submerged below the surface  420  of the cooling liquid  412 . Thus, the potential for leaks that may occur within the upper condenser  460  leading to short circuits or other electrical problems within the immersion cooling tank  400 / 500  is minimized and/or substantially eliminated. 
     According to the described embodiments, the PDUs  425  can provide either AC or DC power, depending on the requirements of the electronic devices and/or components being powered. In one or more embodiments, the PDUs  425  can also be blind-mated for additional service benefits. Also in one embodiment, the immersion cooling tank  400 / 500  can be configured to include a power distribution system or Bus Bar type infrastructure that is embedded into the server rack in order to enable hot pluggable power to a server chassis that is subsequently inserted into the server rack. The power distribution system is generally presented by power connector  415  with power cable  427  extending from PDUs  425 ; however, alternate methodologies are possible for coupling power to the submerged electronic devices requiring electrical power, including the utilization of at least one of a PDU, transformer, inverter, and a power delivery appliance, which can be either internal or external to the immersion cooling tank  400 / 500 . 
     According to one aspect, submerging the PDUs  425  in the dielectric liquid provides an enhanced heat transfer coefficient to the power conductors of the PDUs  425  due to the contact with the cooling liquid. This cooling, which minimizes temperature-induced resistances within the (power transporting) metal conductors of the PDUs, increases a current-carrying capacity of the power transport conductors and the PDUs and further results in a reduction in the internal power losses of the PDUs  425 , greater power transfer efficiencies, and greater PDU capacity. 
     Each of the presented figures of immersion cooling tanks (e.g., previously presented  FIGS. 4 and 5  and later presented figures) illustrates the placement of PDUs  425  within example immersion cooling tank  400 / 500 . In the illustration of  FIGS. 4 and 5 , PDUs  425  are placed in a side location of the immersion cooling tank  400 / 500  away from the actual rack space, and the PDUs  425  are then connected via power cables  427  to the power connectors (generally shown) at the base of the server(s)  200 / 300 . Importantly, PDUs  425  are located below liquid surface  420 , and the determination of liquid surface level  420  and response mechanisms in place to monitor and/or control the liquid level would take the location of the PDUs into account to ensure the PDUs  425  remain below the liquid surface level  420 . 
     As illustrated by  FIG. 18 , power cables  1875  extend beneath the cooling liquid surface from the PDUs  425  to the powered devices, of which first two servers  200  are shown connected. As further illustrated by  FIG. 18 , the feedback and/or control mechanisms within immersion cooling tank  1800  can also include vertical thermistor array  1815 , float or fluid level sensor  1820 , which detects a current fluid level  1625  of cooling liquid within the immersion cooling tank  1800 , conductivity strip  1825 , and flow control valve  497  and external pipe connector  495  which connects the immersion cooling tank  1800  to a multi-rack immersion liquid distribution system, in one embodiment. One or more of these components and/or the collection of these components can be utilized to ensure that the liquid level within the tank  400 / 500  remains within the acceptable range of cooling liquid volume required. 
     E. Partitioned, Rotating Condenser Units to Enable Servicing of Submerged IT Equipment Positioned Beneath a Vapor Condenser 
     As presented by the above descriptions, one aspect of the disclosure involves the recognition that a passive 2-phase immersion cooling system requires a condensing unit to be placed gravitationally above the heat dissipating servers. Another aspect of the disclosure provides a design of the immersion cooling tank that includes a lid structure comprised of multiple rotating condensers. With these designs, the condensers of the immersion tank are configured as separate adjacent condenser based covers over separate vertical spaces. The separate condensers are referenced herein as condenser sub-units, to indicate that each represents a sub-part of a larger condenser or condenser system. Each condenser sub-unit is rotatable to an open position to expose and/or provide access to a server blade or other electronic device located below that partition. The individual partitions allow for servicing/maintenance to be performed on an exposed server blade, while allowing the system to continue operating and cooling the remaining immersed server blades (including those directly adjacent to the exposed blade) using the remaining condensers that remain in place over the rising vapor. 
     One existing solution to cooling server racks utilizes a condenser that coils around the outer rim of an IT rack for immersion cooled IT servers. This solution has inherent limitations with respect to the solution&#39;s cooling capacity and the solution&#39;s ergonomic flexibility, as the height of the cooling structure (rack or tank) must be grown to accommodate the condenser coils. Also, existing solutions to the challenge of accessing individual server nodes operating in an immersion environment are limited to routing the condenser tubes around the outer rim of the IT rack. With this design, access to the server nodes allows for a significant amount of vapor escape during service events and necessitates that the rack footprint grow outwards—increasing overall cost and service time. Accordingly, another aspect of the disclosure is the recognition that the conventional methodology parasitically limits the available condenser surface area for vapor to liquid phase change during even a minimal service, and thus limits the total cooling capacity of the system. Once the cover to the tank is opened, the entire volume of rising vapor escapes the system, resulting in loss of vapor/liquid mass, which unnecessarily leads to significant cooling fluid replacement costs. The disclosure presents a more desirable and functional design that allows one to gain access to individual server nodes in a blade or multiple chassis rack without disrupting the condensation process and/or while allowing only a minimal amount of vapor to escapes during the service event. 
       FIG. 8  shows an example three dimensional rack-configured immersion cooling tank  800  designed to support multiple side-by-side electronic devices, such as servers  200 / 300 , within a server rack (not specifically identified), where at least a portion of the electronic devices are submerged in cooling liquid for cooling of the electronic components located below the surface of the cooling liquid. Immersion cooling tank  800  is a three dimensional view of a practical example of the schematics of immersion cooling tank  400 / 500  and includes a tank volume (see  FIGS. 4-5 ) containing a dielectric fluid (not shown). For continuity, immersion cooling tank  800  shall be described with reference to features presented in  FIGS. 4 and 5 , where applicable. In  FIG. 8 , immersion cooling tank  800  is shown without its front panel, which is made transparent (i.e., not visible) in order to provide a clear view of the rack space, servers, and other components and features inside the tank volume. 
     Immersion cooling tank  800  includes exterior casing  805  and a base panel  810 . The specific design of the casing  805  can vary from one embodiment to the next, and is thus not limiting on the disclosure. Included in base panel  810  are one or more wheels  812  to enable the immersion cooling tank  800  to be moved along the ground surface on which the immersion cooling tank  800  is located. 
     Additionally, immersion tank  800  includes a dry tank  820  coupled to an exterior side panel. Dry tank  820  can be utilized to allow other air-cooled IT equipment to be physically coupled or co-located with an immersion-cooled IT rack. Dry tank  820  accommodates those other IT components that are typically paired with volume servers within the resulting datacenter, but which components cannot be easily immersed in liquid. Examples of these liquid-incompatible devices or components include, but are not necessarily limited to, rotating HDDs and network switches. Another aspect of the design can include an overhead storage compartment for HDDs, power, switches, etc. Thus, in one embodiment, rather than rule out immersion cooling for IT servers that require or include these types of components that are required to be locally coupled, one aspect of the design of the immersion cooling tank involves providing a detachable, containment structure for “top of rack switches” to be paired with the immersion tank. These compartments can be placed on either side of the immersion rack, designed with attachments on either or both sides, or overhead to save floor space. Also, these compartments can provide additional storage for large JBOD (just a bunch of disks/drives) or HDD clusters that cannot be immersed in liquid. 
     It is appreciated that one rack implementation that does not involve use of liquid-incompatible devices or components is a rack design for and/or requirement that servers use SSD drives, “diskless” configurations, or external, remote storage solutions. The present design appreciates and resolves the problem of latency deficiencies inherent with use of remote storage by ensuring the storage components are attached to the tank in a locally external configuration of the server. Also, the present design also appreciates and resolves the problem of latency and increased cabling costs when switches are mounted in centralized network switch trees. 
     Immersion cooling tank  800  includes a plurality of electronic devices and/or components, including servers  200 / 300  and other devices  830 , some of which are rack mountable. As illustrated, a plurality of electronic devices, including servers, can be aligned and/or inserted in a side-by-side configuration within the rack (not shown).  FIGS. 4 and 5  illustrate the example vertical orientation of these servers  200 / 300  relative to the tank volume. With the exception of HDDs, where provided, these electronic devices can be submerged or partially submerged in the dielectric fluid. 
     In one embodiment, the collection of servers  200 / 300  represents a data center. Further, in this embodiment of immersion cooling tank  800 , the cooling liquid (e.g.,  412 ,  FIG. 4 ) is a dielectric that has high volatility (i.e., low boiling point) relative to the temperature increase of the cooling liquid caused by the heat dissipation from the operating servers  200 / 300 . Accordingly, during normal server operations, the operating servers  200 / 300  dissipate heat sufficient to raise the temperature of the dielectric liquid  412  to the boiling point temperature of the dielectric liquid  412 , and this rise in the cooling liquid temperature caused by the heat dissipation from the servers causes the vaporization of the dielectric liquid ( 412 ) generating dielectric vapor ( 422 ) as described with reference to  FIGS. 4 and 5 . 
     As further illustrated, immersion cooling tank  800  includes one or more PDUs  425 , which provide the electrical power required by the electronic devices to operate. As shown, PDU(s)  425  are located below the surface layer  420  ( FIG. 4 ) of dielectric fluid. The PDU(s)  425  are connected to the electronic devices and to an external power source via power cable(s)  875 . 
     Immersion cooling tank  800  includes a tank cover  880  that is connected to the tank via a hinge mechanism and which allows the interior volume of the tank to be sealed. When the cover is placed over the tank, the tank is sealed to be air-tight, such that no vapor can escape through the seal created. Creation of this air-tight seal can involve the use of a rubber or other impervious material along the perimeter edges of the tank cover  880  and/or the top of the lower tank volume at which the tank cover interlocks. Located within the tank cover  880  is a bellows  890 . As described in greater details in Section I, bellows  890  serves as a vapor pressure regulator during operation of immersion cooling tank as a two-phase heat exchange cooling vessel. 
     As indicated by  FIGS. 4 and 5 , the various embodiments of the disclosure present a condenser  460  that is used to extract heat from the rising vapor from a liquid to vapor phase change system. As with these illustrations, during operation of the immersion cooling tank  800 , a portion of the dielectric cooling liquid within the lower volume of the tank evaporates to create a plume of rising vapor ( 422 ). According to one embodiment, the tank is configured such that a condenser (generally represented as condenser  860  herein) is placed gravitationally above the heat dissipating servers, in the direct path of the rising vapor ( 422 ). The use of the cover assembly including the condenser provides a substantially impervious seal for the tank volume to ensure that the rising vapor within the tank volume cannot escape the tank volume while the condenser  860  is fixably rotated to a closed position over the specific vertical space of the lower tank volume that is below the condenser  860 . 
     As further provided by the example embodiment of  FIG. 8 , the condenser  860  is designed as multiple condenser sub-units  860 A-H within the upper volume  404  and located below the tank cover  880 . Each condenser sub-unit  860 A-H represents a partition of the overall condenser  860  and is connected to the tank casing via a rotatable hinge  880 . The rotatable hinge  880  enables each condenser sub-unit  860 A-H to be rotated a number of degrees (e.g., 90-180 degrees) away from a fully closed position. In one or more embodiments, the individual condenser sub-units  860 A-H are rotatable from a closed position of 0 degrees to an open position ranging from greater than 0 degrees to a maximum number of degrees, where the maximum number of degrees is sufficiently large to allow access to the vertical space below the condenser sub-unit within the tank volume to access and/or remove a server or other device that is placed within that vertical space of the tank volume. 
     According to one aspect, each individual condenser sub-unit  860 A-H includes a separate condensation surface  865  from each other individual condenser sub-unit and a separate local conduit  867  for providing condensation fluid to cool the separate condensation surface. During an opening of a first condenser sub-unit (e.g.,  860 F), each other individual condenser sub-unit that remains in a closed position continues to provide condensation of the rising vapor from the lower tank volume, while the first condenser sub-unit ( 860 F) is open. Thus, an opening of the first condenser sub-unit ( 860 F) does not hinder or prevent ongoing condensation from occurring at each adjacent second condenser sub-unit ( 860 E,  860 G) and the other non-adjacent condenser sub-units ( 860 B- 860 D,  860 H) that remains in the closed position. 
     Thus, according to the above introduced aspect of the disclosure, the immersion cooling tank  800  includes: a tank volume comprised of side walls and a base that allows a cooling fluid ( 412 ) to be maintained and heated therein; a rack structure within the tank volume having server rails that supports removable insertion of a server-based information handling system (e.g., server  200 / 300 ); and a cover  880  that encloses the tank volume and which is designed with a condenser  860  configured as a plurality of condenser sub-units  860 A-H. Each of the plurality of condenser sub-units  860 A-H is rotatably connected via a hinge mechanism  870  to the tank wall or several rails (or other fixed component) and can be individually rotated from (1) a closed position in which a vertical space below the condenser sub-unit  860 A-H within the tank  800  is sealed to allow condensation to (2) an open position in which exposure and/or access to the inside of the vertical space is provided. The hinged mechanism  870  enables each individual condenser sub-unit (e.g.,  860 F) to be opened independent of the other sub-units (e.g.,  860 G), and each other condenser sub-unit can remain in a closed position while any one of the condenser sub-units is opened. 
     This partitioning of the condenser  860  into condenser sub-units  860 A-H enables access to one or more of (1) a particular HDD  125  physically located below the particular rotatable condenser sub-unit  860 A-H; or (2) a particular server  200 / 300  that is inserted into the server rack at a vertical plane or location relative to the directional run of the servers within the immersed server rack.  FIG. 8  illustrates the horizontal run of side-by-side servers, each extending upwards into respective vertical spaces. A separate condenser sub-unit  860 A-H is located above each separate vertical, such that the corresponding condenser sub-unit  860 A-H is located above a particular server  200  (inclusive of HDDs) and/or server  300  and locally extern HDDs  125 . 
     Illustrated at the back of immersion cooling tank  800  are a plurality of network cables  850 , representing network cable bundle  450  of  FIGS. 4 and 5 . As described above, one or more of network cables  850  are coupled to the communication and data connectors of one or more servers  200 / 300  or other electronic devices  505  (and/or HDD  125 , if provided). Also, illustrated at the back left section of immersion cooling tank  800  are intake and outflow valves  856 A and  856 B respectively connected to intake pipes  855 A and outflow pipes  855 B through which condensation liquid flows. 
     Additionally, four insets, labeled A-D, are presented in  FIG. 8 . Insets A and B illustrate and/or provide additional details about possible internal configuration within vertical spaces below condenser sub-units, while insets B and C illustrate example make up of the condenser sub-units themselves. Specifically, inset A illustrates example server  200  placed within the server rack space extending vertically below condenser sub-unit  860 A, while inset B illustrates example server  300  with externally local HDDs  125  placed within the server rack space extending vertically below condenser sub-unit  860 F of immersion cooling tank  800 . As shown by the insets C and D of  FIG. 8 , described hereafter, each condenser sub-unit  860 A-H includes a condensation surface  865  and a condensation fluid (not shown) that flows proximate to the condensation surface  865  through pipes  867 . The configuration of the pipes  867  within condenser subunits  860 A-H can be a simple loop as illustrated by pipes  867 A of inset C or can be much more intricate as provided by pipes  867 B of inset D. The latter configuration of pipes  867 B with inset D provides a greater surface area that is exposed to the rising vapor ( 422 ) for condensation thereof. The external surface of the tubular piping can, in one embodiment, provide the condensation surface for the condenser  860  or condenser sub-units  860 A-H. 
     In one embodiment, the condensation fluid flows through the interior bore of the tubular pipe from an external fluid source/reservoir. In another embodiment, the heat exchange with the condensation fluid occurs locally via a radiator type structure attached to the exterior of the immersion cooling tank  800  such that no external piping is required. In yet another embodiment, as illustrated by  FIG. 12 , a stand alone immersion cooling tank can be configured with the exterior atmospheric air operating as the condensation fluid that cools the rising vapor ( 422 ). These two latter implementations enable aspects of the stand alone immersion cooling tank described in the following section. 
     According to the above described aspects of the disclosure, the singular rack condensing unit position at the top of the immersion cooling tank is designed as and/or partitioned into a plurality of sub-condensers that can be individually serviced or rotated to enable access to each individual server chassis (first node) without interrupting the condensation process of the adjacent nodes. While described as a singular assignment of partitions to server nodes, or vice versa, the granularity of the partitions is a design choice. As such, in other embodiments, two or more server nodes can be located beneath a single condenser partition so long as the system has at least one additional partition and one addition server node located beneath that one additional partition. As designed, the individual partitions of the condenser are each capable of being rotated at least a minimum number of degrees (e.g., 90 degrees) from a closed position to enable servicing of IT equipment during runtime, without interrupting the flow of liquid through the condenser surface and/or requiring any other uptime interruption of the data server. As demonstrated by  FIG. 8 , with the immersion cooling tank  800 , while one server is exposed by opening the condenser sub-unit (e.g.,  860 A or  860 F) vertically above the server, the other servers remain submerged in a cooling fluid. The cooling fluid continues to boil and generate rising vapor, which then condenses on the closed condenser sub-units  860 B- 860 E,  860 G- 860 H) to perpetuate the heat transfer cycle, while the exposed server(s) (e.g., below condenser sub-units  860 A,  860 F) can be serviced. 
     In one or more embodiments, the number of individual condenser sub-units is numerically correlated to a fixed number of servers that can be accessible via the opening of the individual condenser sub-unit. Thus, a single server or a plurality of servers can be located within the vertical space below the condenser sub-unit. Also, a power switching unit (PSU), of HDD, or other electronic device being cooled via vaporization-condensation fluid cycles can also be located within the vertical space. 
     F. Condensation Liquid Distribution System and Thermodynamic Stepping of Multiple Working Fluids to Provide Cooling of Target Space 
     According to one or more embodiments, condenser sub-unit  860 A-H ( FIG. 8 ) and in particular the condensation surface  865  comprises at least one extended length of tubular piping extending from an external pipe running to the inside of the enclosure via an intake path and then back to the outside of the enclosure via an out flow path. According to one embodiment, the external ends of the tubular piping  855 A-B ( FIG. 8 ) of immersion cooling tank  800  can be connected with an external condensation fluid source, which can be working fluid reservoir  920  ( FIG. 9 , described hereafter) to create a condensation loop, with the condensation fluid being a first working fluid. In one or more embodiment, immersion cooling tank  800  also includes a condensation liquid distribution system connected to and/or including the condenser sub-units  860 A-H. Condensation liquid distribution system includes a network of pipes  855  that run into and out of each condenser and/or condenser sub-unit  860  and connect to a main piping system, which can include connecting end valves, for facility water connection. Two end valves are illustrated, consisting first of intake valve  856 A, at which condensation fluid is received from the external reservoir and passed to the condenser sub-units  860 A-H. The second valve is the outflow valve  856 B at which the heated or evaporated condensation fluid passes back towards the condensation fluid reservoir on the outside. Notably, as illustrated by the inset figure showing an internal makeup of condenser sub-unit, each sub-unit can consist of a single loop of piping  867  proximate to a “separate” condensation surface  865 . The actual number of such loops of piping  867  can vary depending on the actual size of each condenser sub-unit, and the inset C and D are provided solely for example to contrast with the larger condensers illustrated within  FIGS. 4 and 5 . 
     According to at least one embodiment, the internal tubes or pipes of the previously introduced condensers  460  ( FIGS. 4-5 ) and condenser  860  ( FIG. 8 ) and/or condenser sub-units  860 A-H are coupled to the condensation fluid distribution system. The condensation fluid distribution system can in turn be connected to an external reservoir from which the condensation fluid flowing into the condenser is provided. The condensation fluid is piped into the condenser  860  at a temperature that is less than the cooling point or condensation temperature of the rising vapor  422 . Within the condenser  860 , the condensation fluid maintains the condensation surface  865  at a lower temperature than a condensation point/temperature of the rising vapor ( 422 ). 
     According to one or more embodiments, the condensing fluid utilized within the condensers  460 / 860  can be water. With the known thermal properties (i.e., vaporization point and condensation point) of the specific dielectric fluid utilized (e.g., Novec fluid), regular water can be utilized. Importantly as well, the water does not need to be chilled or cooled to provide the condensation of the rising vapor and as such can be pulled from a facility water source reservoir. Thus, ambient water is received from a facility water source (or reservoir) as condensation liquid that condenses the rising vapor ( 422 ) from the dielectric fluid. The latent heat transfers from the vapor ( 422 ) to the water, and the water is eventually returned back to the facility reservoir. Notably, in one embodiment, this heated water can then be utilized for other uses, such as to heat the facility or other structure, etc., within an example environmental application. 
       FIG. 9  shows an example of one possible implementation of an environmental application that provides secondary heating based on the heat absorbed by the condensation fluid flowing through condensers  460 / 860 . Server  200  represents a heat source that is submerged in an immersion cooling tank (not shown) and operated while submerged below a cooling liquid to cause vaporization of the cooling liquid. Example condenser  460  is a two phase condenser which receives condensation liquid at the intake pipes. Condenser  460  absorbs the heat from the rising vapor (V 1 ) and condenses the vapor back to liquid (L 1 ), which returns to the immersion cooling tank. According to the illustrated embodiment, the amount of heat absorbed from the rising vapor (V 2 ), i.e., the latent heat dissipation required for heat change from vapor to liquid condensate, can be sufficient to evaporate the condensation liquid (L 2 ) into a condensation vapor (V 2 ) as the heat is absorbed by the condensation liquid flowing within the condenser. This condensation vapor can then be forwarded to a facility pump  910 , which pushes the condensation vapor (V 2 ) towards a heat recovery system  920  for a building or other location requiring heat. Heat recovery system  920  of the building can include a third condensation liquid (L 3 ) which can absorb the heat from the condensation vapor (V 2 ) and in turn vaporize to generate a third condensation vapor (V 3 ). With the latent heat removed, at least a portion of the condensation vapor can condense back to a condensation liquid (L 2 ). This condensation liquid is then sent to an evaporative cooling tower  930 , where any additional latent heat is removed from the received fluid such that the remaining vapor condenses back to condensation liquid. The cooling tower  930  operates as the facility water source reservoir in this example. 
     Turning now to  FIG. 10 , there is illustrated an example fluid-based heat exchange system that can be utilized with an immersion cooling tank  400 / 500 / 800  to allow for stepped heat exchange via a plurality of different working fluids.  FIG. 10  generally illustrates a method and system for providing cooling of a target space, i.e., the immersion cooling tank  1000 , in which heat is being dissipated. Specifically, the figure illustrates a method and system for cooling components disposed within an immersion tank that supports two-phase cooling of an immersion server via an vaporization-condensation cycle utilizing a volatile (i.e., low boiling point) immersion liquid. In  FIG. 10 , a first dashed box (first fluid transformation  1005 ) represents an example heat exchange components of an immersion cooling tank  700 , where a cooling liquid  412  is evaporated into vapor  422 , which vapor is then condensed into a condensate  462  that returns to the cooling liquid volume. A second dashed box (cooling liquid distribution system  1010 ) represents the fluid exchange or replenishment between a cooling liquid reservoir  1020  and the volume of cooling liquid  412  within the immersion cooling tank  1000 . The methodology for supplying cooling liquid  412  to the immersion cooling tank  1000  can vary, and one example is provided within Section H, described hereafter. A third dashed box (condensation liquid distribution system  1015 ) then represents the heat exchange system, which includes a first heat exchanger or condenser  860  and can include a working fluid reservoir  1030 . 
     The heat exchange system diagram of  FIG. 10  illustrates both sides of a two-phase vaporization-condensation cooling system  1000 , which includes a cooling liquid distribution system  1010  and a condensation liquid distribution system  1015 . Two-phase vaporization-condensation cooling system  1000  provides a first tandem of vaporization-condensation fluid transformations  1005  within an example immersion tank, which is assumed to be immersion tank  800  ( FIG. 8 ) in this example. With this first fluid transformation  1005 , a volume of cooling liquid  412  is evaporated into vapor  422  and the vapor is then condensed back into cooling liquid condensate  462  by a condenser  860 , which represents a first heat exchanger (Ex_ 1 ). Condenser  860  has a surface  865  at which the two working fluids are able to come into proximity with each other in order to allow for the heat exchange from vapor  422  to condensation liquid  1022  to generate condensation vapor  1024 . The volume of cooling liquid  412  can be obtained from a cooling liquid reservoir  1020 , which serves to replenish the level of cooling liquid  412  within the immersion tank  800  in the event of a leak and/or loss of fluid from immersion tank  800 . According to one embodiment, a sensor and/or feedback mechanism that includes an intake flow control valve (e.g.,  497  ( FIG. 4 )) attached to the piping from cooling liquid reservoir  1020  can be provided with the immersion tank  800  to automatically maintain the fluid levels in the immersion tank  800  at a desired level. 
     In  FIG. 8 , a first heat exchanger is represented by condenser  860 . The condensation which occurs within first heat exchanger involves a flow of condensation liquid, which occurs within condensation liquid distribution system  1015 . As shown by  FIG. 10 , condensation liquid distribution system  1015  includes a condensation liquid reservoir  1020  connected via a system of pipes, which are generally indicated as inflow pipes  1022  and outflow or return pipes  1024 . It is appreciated that the system of pipes necessarily includes intake and return pipes  855 A-B of condenser  860  ( FIG. 8 ). Condensation fluid flows from condensation fluid reservoir  1030  and enters condenser  860  as a liquid having a lower temperature relative to the vapor temperature and/or the ambient temperature within upper volume of the immersion cooling tank  800 . In one embodiment, the condensation liquid absorbs heat form the vapor  422  causing the vapor  422  to condense back into cooling liquid condensate  462 . The heat absorbed by the condensation fluid increases the temperature of the condensation fluid and generates heated condensation fluid, which is returned to the condensation liquid reservoir  1020  for cooling, in one embodiment. In another embodiment, the condensation fluid enters the condenser in liquid form and the amount of heat absorbed by the condensation liquid is sufficient to boil the condensation liquid. This boiling results in a phase change from condensation liquid to condensation vapor, which can be returned to the condensation liquid reservoir  1020  for cooling, in one embodiment. 
     According to one embodiment, condenser  860  can be referred to as heat exchanger  1 , to indicate alternate implementations in which multiple vaporization-condensation cycles are chained together between the immersion cooling tank  800  and the “final” reservoir  1030  or final heat exchange medium. Thus in  FIG. 10 , the dots that extend left of the reservoir  1030  indicate that additional heat exchangers and associated working fluids can be included within the chain, prior to final cooling at the reservoir  1030  or other form of final heat exchange medium, such as the atmosphere. Each subsequent heat exchanger would then utilize the heated condensation liquid of the previous heat exchanger as the heat source that ultimately provides the required heat energy at that heat exchanger which the heat exchanger extracts and provides to heat the intake of condensation fluid by the heat exchanger. Implementation of this more complex heat exchange methodology can require use of different condensation fluids as the working fluid at each heat exchanger, where the different boiling and condensation temperatures allow for a phased heating and cooling cycle until the final heat exchanger or reservoir  1030 . It is appreciated that the final heat exchanger can be the atmosphere, where the heated working fluid is cooled by contact with regular air. 
     According to another aspect, and as shown in greater detail by the inset drawing of  FIG. 10 , which is further exemplified in  FIG. 11 , a plurality of heat exchanges are arranged in tandem with each other. Each heat exchanger can have a different working fluid. Alternatively, two or more of the heat exchanges can share a working fluid, but with the working fluid maintained at different pressures. In the inset drawing a four-condenser chain of interconnected heat exchangers is provided, namely first heat exchanger (Ex_ 1 )  860 , which is also condenser  860 , second heat exchanger (Ex_ 2 )  1040 , third heat exchanger (Ex_ 3 )  1045 , and fourth heat exchanger (Ex_ 4 ), which is also reservoir  1030 , in one embodiment. Each heat exchanger operates with a working fluid that has a different relative saturation temperature Tsat from the adjacent upstream and/or downstream heat exchanger(s). According to one aspect, the saturation temperature, T saturation , of each working fluid is has a stepped relationship relative to each adjacent working fluid, such that:
 
 T   saturation1   &gt;T   saturation2   &gt;T   saturation3  . . . ,
 
where T saturation1  is the saturation temperature of the cooling fluid, T saturation2  is the saturation temperature of the first working fluid, and so on. According to one embodiment, the difference in saturation temperatures can be controlled by utilizing dissimilar working fluids. In another embodiment in which the same working fluid is utilize within multiple heat exchangers, the saturation temperatures can be controlled by holding the working fluid at dissimilar pressures, where greater pressure reduces the saturation temperature of the working fluid.
 
     Referencing the illustration of  FIG. 11  along with aspects of  FIG. 8 , an embodiment of the disclosure provides a system that includes: an immersion cooling tank having one or more operating components that dissipate heat and which are submerged in a first cooling liquid ( 412 ) that absorbs the dissipated heat, such that a portion of the first cooling liquid ( 412 ) evaporates and generates a rising plume of vapor ( 422 ) within the immersion cooling tank. The system further includes a first heat exchanger ( 860 ) associated with the immersion cooling tank and which includes a first working fluid flowing through a first conduit connected to a first condenser unit having at least one surface  865  that is exposed to the rising vapor  422 . The first working fluid absorbs heat from the rising vapor ( 422 ) to cause the rising vapor  422  to undergo a phase change into a corresponding portion of first cooling liquid condensate  462 . The system further includes at least one second heat exchanger  1140  that is physically coupled to the first conduit through which the first working fluid passes after absorbing the heat from the rising vapor. The second heat exchanger  1140  includes a second working fluid flowing through the second heat exchanger outside of the first conduit. The second working fluid absorbs heat from the first working fluid as the first and the second working fluids come into proximity with each other within the second heat exchanger (see inset of  FIG. 10 ). In one embodiment, the second working fluid flows through a second conduit co-located proximate to the first conduit. 
     In one embodiment, the system further includes: at least one third heat exchanger  1145  that is physically coupled to the second conduit through which the second working fluid passes after the second working fluid has absorbed the heat from the first working fluid. The third heat exchanger  1145  includes a third working fluid flowing through the third heat exchanger  1145  outside of the second conduit. The third working fluid absorbs heat from the second working fluid as the second and the third working fluids come into proximity with each other within the third heat exchanger. In one embodiment, the third working fluid flows through a third conduit co-located proximate to the second conduit. 
     According to one embodiment, the first working fluid enters the first heat exchanger ( 860 ) as a liquid and at least a portion of the liquid evaporates into vapor form due to the absorption of the heat being dissipated within the target space (e.g., the interior volume of the immersion cooling tank  800 ). The vaporized first working fluid is then condensed back to a liquid form of working fluid at the second heat exchanger  1140 . 
     According to one or more embodiments, the target space is the inside of one of (a) an immersion server drawer and (b) an immersion server tank, and the heat being dissipated within the target space is heat generated during operation of one or more functional components of an operating server located within the target space. Within this embodiment, the processing components of the servers are immersed within a dielectric fluid, which evaporates to generate dielectric vapor that is then condensed back to dielectric liquid by the first heat exchanger  860 . According to one embodiment, the first heat exchanger  860  and the second heat exchanger  1140  are condensers. 
     One additional aspect of the disclosure provides a method that includes: providing a first heat exchanger within the target space to absorb heat from within the target space using a first working fluid that is flowing through the first heat exchange; and circulating the first working fluid egressing via a first conduit from the first heat exchanger to be re-utilized within the first heat exchanger by passing the egressing first working fluid through a second heat exchanger that has a second working fluid flowing through a separate, second conduit. The method further includes: enabling the second working fluid egressing from the second heat exchanger to be cooled via one of a third heat exchanger, a reservoir, and the atmosphere before circulating the second working fluid back to the second heat exchanger. The first working fluid has a heat absorption coefficient that is greater than the heat being dissipated within the target space. The second working fluid has a heat absorption coefficient that is greater than the heat being dissipated by the first working fluid as the first working fluid passes through the second heat exchanger. 
     Thus, according to one or more embodiments, the heat exchanger portion of the immersion tank implementation employs fluids of dissimilar saturation temperatures to achieve the two-phase heat transfer on both the exterior of the condenser and the interior of the condenser in a combined Condenser/Evaporator configuration. This aspect of the disclosure recognizes that while single-phase fluids can provide excellent cooling capacity in forced convection environments, the single-phase cooling methods are burdened with the hydraulic power cost for pushing mass at high velocities across a heat transfer surface. This penalty, which can be in the form of an increase in fan power or pumping power costs, represents a source of inefficiency for the cooling of heat dissipating devices. 
     Accordingly the disclosure provides a two-phase or mixed phase flow, which can provide equal or greater cooling capacity as single-phase fluid flow at a fraction of the total mass flow rate by utilizing combined latent and sensible heat transfer. As utilized herein, the condenser represents a form of heat exchanger in which a saturated vapor on one side of the exchange medium transfers latent energy to a sub-cooled fluid on the other side of the exchange medium in order to transition state from vapor to liquid. Additionally, an evaporator is a form of heat exchanger in which a saturated liquid on one side of the exchange medium receives latent energy from a heated fluid on the other side of the exchange medium in order to transition state from a liquid to vapor. 
     According to one or more embodiments, a solution is presented that couples fluids of dissimilar saturation temperatures such that the condensing process of cooling fluid A (e.g., condensation liquid/vapor flowing from first heat exchanger  860 ) induces vaporization of working fluid B (e.g., condensation liquid/vapor flowing from second heat exchanger  1140 ), where working fluid B has a lower saturation temperature than cooling fluid A. This aspect of the disclosure effectively provides “condensation by vaporization” and/or “vaporization by condensation”. In performing this form of dual-sided heat exchange, both sides of the heat exchanger will gain performance from a two-phase heat transfer coefficient, as illustrated by the below equation:
 
Single-phase heat transfer:  Q=m dot* Cp*dT  
 
Two-Phase heat transfer:  Q=m dot*( Cp*dT+Hlv )
 
     Additionally, the process requires lower mass flow rate to transport the same quantity of heat. As an additional enhancement to this process, one aspect of the disclosure also provides “Thermodynamic Stepping”, which is a cooling loop using a plurality of fluids with dissimilar saturation temperatures to create multi-phase cooling from heat dissipating component to a final exterior heat sink. According to one or more embodiments, a heat transport loop is provided that employs a plurality of the “combined evaporator and condenser” heat exchangers. Within the loop, fluids of dissimilar saturation temperatures can be nested to create cascading phase change heat transfer. The difference in saturation temperature can be a result of dissimilar fluid composition or pressure modulation. The features presented are thus able to accommodate the cooling or heating needs of very complex environments. For example, these aspects of the disclosure are applicable to complex industrial fabrication facilities that require differentiated cooling of different species. Within this environment, the thermodynamic stepping can be applied to minimize the number of cooling loops within their control systems and increase operational efficiency. 
     The above described illustrations of  FIGS. 10 and 11  provide one example of the application of this cascading cooling loop in an advanced data center that utilizes immersion-based cooling of IT servers. Heat generated at the electronic component level initiates boiling of a saturated cooling liquid. The vapor from that boiling process can then be condensed as the vapor passes across the coils of heat exchanger. The condensation heat transfer would cause the facility coolant to boil and pass into a vapor state. The mixed-phase facility coolant could then be routed to an exterior cooling tower that deploys ground-water on the surface of the heat exchanger to provide evaporative cooling on the surface of the cooling tower. This vaporization would then reject the heat sufficiently enough to condense the facility mixed-phase coolant. 
     Generally, the above illustrations provide a system for heat exchange that includes: a first condenser that places a first working fluid vapor in proximity to a second working fluid liquid, where the two working fluids have respective saturation temperatures that causes the liquid form of the second working fluid to absorb sufficient amounts of heat from the first working fluid vapor to vaporize, while the first working fluid vapor condenses back into a liquid form. The second working fluid vapor exits the first condenser via a first conduit and enters a first heat exchanger which places the second working fluid vapor in proximity to a third working fluid liquid. The relative saturation temperatures of the second and third working fluids is such that the proximity of the second working fluid vapor with the third working fluid liquid causes the transfer of sufficient amounts of heat from the second working fluid vapor to cause the second working fluid vapor to condense back into its liquid form while at least a portion of the third working fluid liquid evaporates into third working fluid vapor. The sequence of vaporization-condensation across paired working fluids can continue until a desired cooling is achieved via the final working fluid. 
     According to a more expansive description, the system for heat exchange includes: a first condenser having a first conduit with a surface at which a first working fluid vapor impacts and through which flows a second working fluid in liquid form. A proximity of the two working fluids enables the liquid form of the second working fluid to absorb sufficient amounts of heat from the first working fluid vapor to cause the first working fluid vapor to condense back into a liquid while at least a portion of the liquid form of the second working fluid evaporates and generates second working fluid vapor that exits the first condenser via the first conduit. The system further includes at least one heat exchanger connected to the first conduit by which the second working fluid vapor is received and which has a second conduit through which flows a third working fluid in liquid form. A proximity of the second working fluid vapor and the third working fluids enables the liquid form of the third working fluid to absorb sufficient amounts of heat from the second working fluid vapor to cause the second working fluid vapor to condense back into its liquid form while at least a portion of the liquid form of the third working fluid evaporates and generates a third working fluid vapor. 
     According to one embodiment, a respective thermodynamic property of the first, second and third working fluids provides a saturation temperature that causes paired coupling of one or more of (a) the first working fluid vapor with a liquid form of the second working fluids, the first working fluid vapor with a liquid form of the third working fluids, and the second working fluid vapor with a liquid form of the third working fluids to result in condensation of the specific working fluid vapor and vaporization of at least a portion of the liquid form of the working fluid paired with the specific working fluid vapor within the corresponding heat exchanger. Further, the flow of the second working fluid within the condenser causes the first working fluid vapor to reject heat which causes the first working fluid vapor to condense and the heat that is rejected by the first working fluid vapor is at least partially absorbed by the second working fluid causing the liquid form of the second working fluid to vaporize at least partially. 
     In one or more of the illustrative embodiments, the first condenser is located within an immersion cooling tank and the first working fluid is an immersion cooling liquid that evaporates within the tank to generate immersion cooling vapor that rejects heat to the condensation liquid flowing through the first condenser and returns to a lower volume of the tank as liquid condensate. 
     G. Scalable, Multi-Tank Distribution System for Liquid Level Control of Immersion Cooling Tanks 
     Liquid cooling technologies (such as contact plate, immersion, spray, etc.) for server heat dissipation in computer rooms and datacenters are subject to liquid coolant volume expansion and contraction as a consequence of temperature fluctuation, air infiltration, vaporization, maintenance or servicing operations, and ambient pressure changes. Any combination of these variables or causes can significantly impact the performance of liquid cooled IT equipment up to and including catastrophic failure without service intervention. With existing liquid cooling technology, the problem of fluid mass/volume fluctuation within rack liquid cooling solutions are accounted for using one of two methods: use of a sealed system with an expiration date; and use of service/maintenance personnel manually adding liquid to maintain control levels. With the first method, the amount of fluid volume is sized to accommodate a fixed period (e.g., 3-5 years) of container permutation, and then the container is either replaced or refilled at the end of that period. 
     According to the one aspect of the disclosure, maintenance of the ideal amount of liquid within the tanks is handled on a multi-tank basis to provide across-the-board support for multiple tanks within a tank-based system or server farm so no one tank requires longer periodicity of maintenance than the others. One aspect of the disclosure involves the understanding that the tanks, while calibrated to operate as efficiently as possible, will not always provide the exact same operating responses or conditions. One reasons for this is that the servers do not all run the same way and generate the same amount of heat, etc. Other reasons include the actual tanks themselves, the condenser unit, the seal, etc. Thus, the disclosure allows for a system level control for maintaining liquid levels across multiple tanks by providing a Multi-Rack Distribution System For It Rack Liquid Level Control that is used for automatic control of liquid coolant volumes in one or more IT racks that incorporate liquid cooling at the server-level. The disclosure involves coupling one or more liquid filled IT racks to a remote expansion/contraction reservoir that can autonomously regulate liquid levels within the rack. According to one embodiment, this fluid level control system can be a passive system that seeks to maintain liquid levels through gravitational equilibrium with a coplanar reservoir and a gravitationally low expansion tank. However, in alternate embodiments, the liquid level is maintained via an active control cycle, having electronic feedback mechanisms within each tank that are electronically linked to a main controller which can open and close valves as required to regulate fluid levels. A hybrid scheme involving some active control loop with a passive gravitational control can also be implemented. According to one or more embodiments, valves may be used to control inlet/outlet fluid flow between rack and expansion/contraction reservoirs. Active and/or passive means can be utilized to recycle expansion fluid back into a contraction regulation reservoir. 
     Accordingly, the scalable system can be sized for one or more racks to simultaneously modulate liquid coolant volumes that fluctuate due to dynamic expansion and contraction and evaporative mass loss. Aspects of this disclosure can specifically target the coolant within the rack, and not the datacenter facility coolant loop or mechanical service. 
       FIG. 12  generally introduces the concept of a cooling liquid reservoir that is coupled to the cooling liquid volume within the immersion cooling tank. This reservoir  1230  provides cooling liquid to the immersion tank as the amount of cooling liquid within the immersion cooling tank falls below a threshold level. The amount of cooling liquid in the tank can change based on vaporization of the cooling liquid and/or loss of cooling liquid and/or cooling liquid vapor through the walls or seams of the tank. Also, with the use of upper condensers and a tank cover, cooling liquid vapor also escapes through the top opening of the tank whenever the tank cover is removed and/or one or more condenser sub-units ( 860 A-H) are opened. 
     According to one aspect of the disclosure, a cooling fluid level of one or more of the immersion cooling tanks can be maintained via a self-leveling configuration of multiple tanks and/or a tank and a cooling fluid reservoir. This aspect of the disclosure provides a fluid level control system for maintaining a level of cooling fluid within at least one immersion cooling tank.  FIGS. 12 and 13  illustrate two different embodiments of a system configured to use a cooling fluid reservoir. In the embodiment of  FIG. 12 , immersion cooling tank  1200  includes a separate condensation channel  1210  extending from the upper volume of the tank  1200 . Condensation channel  1210  includes upper condensers  1260 , which condense vapor received within the channel to generate cooling liquid condensate  1262 . As the cooling liquid boils in the lower volume of immersion cooling tank  1200 , the rising vapor  422  flows upwards and into this condensation channel  1210 , where the vapor condenses. It is appreciated that the use of different condensation techniques, such as wrapping condensation pipes around the channel to trigger or cause the condensation of the rising vapor, can be implemented in lieu of providing condensers within the interior volume of the condensation channel  1210 . 
     As further shown by  FIG. 12 , the cooling liquid condensate  1262  can be returned to the tank volume via one or three alternate paths, with each path being a design choice. Path A is a direct return path to the cooling fluid volume within immersion cooling tank  1200 , which utilizes gravity, whereby the condensate  1262  runs back into the cooling liquid volume. Path B also involves the use of gravity but can optionally involve the use of a pump  1240  to move the collected condensate  1262  through the intake valve  1297  of the immersion cooling tank  1200  back into the volume of cooling liquid. Of specific interest to the present disclosure is path C, which involves use of reservoir  1230 . Path C includes first piping, C 1 , which provides the cooling liquid condensate  1262  to the reservoir  1230 , and second piping, C 2 , which provides additional supply of cooling liquid  1212  to immersion cooling tank  1200  via a pipe system that can include intake valve  1297 . Second piping can also involve a pump  1240  in one embodiment. However, the embodiments described herein rely on gravitational forces to cause the flow of fluid from one liquid volume to the next. 
     With specific reference now to  FIG. 13 , and utilizing the example immersion cooling tank  400 / 500  introduced by  FIGS. 4 and 5 , the cooling liquid level control system  1300  includes at least a first immersion cooling tank (ICT_ 1 )  400 A configured to hold a first volume of immersion cooling liquid ( 412 ) that can be utilized to cool one or more servers (not shown) that are submerged in the cooling liquid  412  within the first immersion cooling tank  400 A. The first immersion cooling tank  400 A includes at least one external pipe connector  495 / 1395  utilized to enable a flow of cooling liquid  412  into and out of the first immersion cooling tank  400 A. The system  1300  also includes at least one secondary volume of cooling liquid (i.e., tank  400 A and/or reservoir  1330 ) that is physically connected to the first immersion cooling tank  400 A via a pipe distribution system  1335 . The pipe distribution system  1335  provides a connection between the external pipe connector  1395  of the first immersion cooling tank  400 A and the secondary volume of cooling liquid ( 400 B and/or  1330 ). 
     In one embodiment, illustrated by the pairing of tanks labeled A, the second volume is a cooling liquid reservoir  1330 , which contains reserve amounts of cooling liquid for use by one or more immersion cooling tanks ( 400 ). In another embodiment, illustrated by the pairing of tanks labeled B, the second volume is a second immersion cooling tank  400 B. In yet another embodiment, the pipe distribution system connects both a cooling liquid reservoir  1330  and a second immersion cooling tank (ICT_ 2 )  400 B to the first immersion cooling tank  400 A and to each other. Finally, in another embodiment, as partly illustrated by  FIG. 13 , the pipe distribution system  1335  is connected to a plurality of second immersion cooling tanks in a tandem or daisy chain configuration. 
     In a first implementation, the second volume of cooling liquid is located co-planar to the first immersion cooling tank, on a same horizontal plane, which results in a measured flow of cooling liquid between the first immersion cooling tank  400 A and the second volume to maintain both volumes at a liquid equilibrium level. This measured flow occurs in response to the first volume of cooling liquid  412  increasing or decreasing its liquid level within the first immersion cooling tank  400 A. First immersion cooling tank  400 A includes a high liquid level threshold  1305 A and a low liquid level threshold  1310 A, which can be monitored by respective, internal liquid level sensors  1320 A and  1322 A, in one embodiment. Similarly, second immersion cooling tank  400 B includes a high liquid level threshold  1305 B and a low liquid level threshold  1310 B, which can be monitored by respective, internal liquid level sensors  1320 B and  1322 B, in one embodiment. In a second implementation, the second volume of cooling liquid provides the measured, single direction flow of new cooling liquid into the first immersion cooling tank in response to the first volume of immersion cooling liquid falling below a low liquid threshold (at liquid sensor  1322 ) of cooling liquid in the first immersion cooling tank  400 A. 
     In one embodiment, the system provides that cooling liquid from the second volume automatically flows through the pipe system into the first immersion cooling tank in response to a reduction in the first volume of cooling liquid. The reduction in the first volume can be a result of loss of one or more of cooling liquid and cooling liquid vapor from the first immersion cooling tank by one or more of a physical leak in the first immersion tank, a pressure induced vapor leak through a seam of the first immersion tank, and a leak of cooling liquid vapor during opening of a tank cover or a condenser sub-unit of the immersion cooling tank. 
     One embodiment provides that the fluid level control system includes: liquid level sensors  1320 / 1322  within the immersion cooling tank, which detect changes in the liquid level not attributable to vaporization of the cooling liquid; a valve assembly  497 / 1397  connected within the external pipe connector  1395 ; and a controller  1350 . In response to a detected change reducing the liquid level of the first volume to below a pre-set level within the first immersion cooling tank, the controller  1350  autonomously triggers an opening of the valve assembly  497 / 1397  to allow new cooling liquid to flow into the first immersion cooling tank  400 A. 
     In one embodiment, the valve assembly  497 / 1397  is selectively controllable to allow a flow of cooling liquid into the first immersion cooling tank and allow the flow of cooling liquid out of the first immersion cooling tank. With this embodiment, when two or more immersion cooling tanks are connected together via the pipe distribution system  1335 , the controller  1350 , triggers the valve assembly  497 / 1397  to open to allow immersion cooling liquid to flow out of the first volume towards the second volume, in response to a second volume of cooling liquid of the second immersion cooling tank  400 B falling below the low liquid threshold for the second immersion cooling tank  400 B. In at least one implementation, the valve mechanism opens the valve based on a gravitational imbalance occurring between the pressure exerted by the volume of immersion liquid within the first immersion tank versus the pressure exerted by the second volume of immersion liquid outside the valve. 
     With the embodiments that provide a cooling liquid reservoir  1330 , the cooling liquid reservoir  1330  can be located at a higher vertical plane than the first immersion cooling tank  400 A. When placed on a vertically higher plane, the cooling liquid reservoir  1330  provides the new immersion cooling liquid to the first immersion cooling tank ( 400 A) via gravitational flow, in response to a current volume level of the cooling liquid within the first immersion cooling tank  400 A falling below a refill threshold level (e.g., threshold level  1322 ). Accordingly, the supply of new immersion cooling liquid enables the first immersion cooling tank  400 A to maintain a working volume of immersion cooling liquid  412  within a range of acceptable levels for effective operation as a liquid coolant for the one or more servers operating within the first immersion cooling tank  400 A. 
     According to one embodiment, the interconnection of the second volume with the first immersion cooling tank  400 A also enables gravitational flow of cooling liquid between the first immersion cooling tank  400 A and the second volume, in response to a change in relative volumes due to loss of fluid within one of the first immersion tank  400 A and the second volume. The gravitation flow of the cooling liquid passively increases and decreases the level of immersion cooling liquid  412  within each of the first immersion cooling tank  400 A and the second volume, based on which volume of cooling liquid has decreased, in order to maintain an equilibrium level between the two liquid volumes. 
     According to one embodiment, in response to the overall volume of cooling liquid within the plurality of immersion tanks falling below a system threshold volume, the controller  1350  generates a signal to open an output valve of the cooling liquid reservoir  1330 . As one additional aspect, one or more embodiments provide that the cooling liquid reservoir  1330  includes a pump  1340  connected to the pipe distribution system  1335  and an electronic controller  1350 . In response to receiving a signal indicating that a current volume of cooling liquid within the plurality of immersion cooling tanks is below the system threshold volume, the controller  1350  activates the pump (not shown) to begin pumping an amount of new cooling liquid from the reservoir  1330  through the pipe distribution system  1335  to increase the system volume of cooling liquid within the plurality of immersion cooling tanks  400  to above the system threshold volume. Accordingly, the use of the feedback controller enables each of the interconnected immersion tanks to maintain a volume above the low liquid level threshold and the collective volume of the plurality of immersion tanks to remain above the system threshold volume. 
     In the embodiments in which each immersion cooling tank comprises a valve mechanism that controls the inflow and outflow of immersion cooling liquid into the respective immersion tank, the detection of the volume of immersion fluid within any one immersion tank falling below the pre-set low liquid threshold causes the controller  1350  to open the valve  497  of at least one other immersion tank to allow a portion of the immersion liquid within that at least one other immersion tank to flow out towards the one immersion tank whose volume of cooling liquid is below the pre-set threshold. 
     In one embodiment, the low cooling liquid threshold is an amount of immersion cooling liquid that enables effective cooling of the electronic component immersed or submerged in the cooling liquid, and the threshold value takes into consideration that a portion of the immersion cooling liquid will be evaporated within the immersion cooling tank and that an amount of the cooling liquid will be in a vapor state during operation of the system. 
       FIG. 14  is a flow chart illustrating one embodiment of a method for providing cooling liquid level control within an immersion cooling tank. Method  1400  begins at block  1402  at which liquid level sensors  1320 / 1322  monitors the liquid level of the dielectric cooling liquid within the immersion cooling tank  400 A and generates a signal that is transmitted to and received by the controller  1350 . At decision block  1404 , method  1400  includes a determination whether the liquid level is below a low level threshold. In response to the liquid level being below the low level threshold, method  1400  includes the controller  1350  transmitting a signal to trigger opening of the intake valve ( 497 / 1397 ) of the immersion cooling tank  400 A (block  1406 ). In one embodiment, the signal stops being transmitted once the low level signal is no longer being received by the controller  1350 . One optional embodiment is illustrated by block  1408  in which a pump is provided within the liquid level control mechanism. With this embodiment, the controller  1350  can also trigger the pump (not shown) to provide a specific volume of new dielectric liquid to the immersion cooling tank  460 . Then, at block  1410 , method includes controller  1350  transmitting a signal to the servers or other devices operating within the immersion cooling tank  460  to throttle the rate of processing in order to reduce the amount of heat dissipation and consequently reduce the amount of vaporization of liquid and generation of vapor within the immersion cooling tank  460 . 
     Returning to decision block  1404 , in response to the liquid level not being below the low level threshold, method  1400  further includes a determination at decision block  1412  of whether the liquid level is above a high level threshold. This second determination is important when HDDs are being vapor cooled above the surface of the cooling liquid, and allows the HDDs to be kept from being immersed due to a rising liquid level. In response to the liquid level being above the high liquid level threshold, method  1400  provides one or more of three possible responses. In a first response provided within block  1414 , method  1400  includes controller  1350  transmitting a first signal to open the outflow valve  1397  of the immersion cooling tank to allow a flow of excess immersion cooling liquid towards the connected reservoir  1330 . In a second response provided within block  1416 , method  1400  includes controller  1350  transmitting a second signal to the servers to increase the processing rates in order to increase the amount of heat dissipation within the cooling liquid and the resulting vaporization of the cooling liquid into rising vapor. In a third response provided within block  1418 , method  1400  includes controller  1350  generating and transmitting an overflow signal to the connected device of a system administrator or IT personnel. The dashed lines around blocks  1408 ,  1414  and  1418  indicate that the contained content is optional and/or alternative in nature. 
       FIG. 15  shows an aerial view of an immersion cooling tank data center  1500 . As illustrated by  FIG. 15 , according to at least one embodiment, the multi-rack immersion liquid distribution system  1500  includes a plurality of immersion cooling tanks  400  that are daisy chained to each other by an interconnection of the pipe distribution system  1505  to respective external pipe connectors (extending from each tank  400 ). Each immersion tank  400  can be similarly dimensioned (i.e., hold a similar volume of cooling liquid in a similarly shaped and sized tank enclosure) and located coplanar to (i.e., on a same horizontal level as) the other immersion tanks. Then, in response to the volume of immersion fluid in any one immersion tank falling below one of an equilibrium point and a pre-set low liquid threshold, a gravitational imbalance occurs and causes cooling liquid to flow from at least one other immersion tank through the pipe distribution system  1505  towards the one immersion tank whose volume of cooling liquid is not at the point of equilibrium or has falling below the pre-set low liquid threshold. With  FIG. 15 , similar to  FIGS. 10 and 12 , the cooling liquid distribution system  1500  can include a multi-rack immersion liquid distribution system reservoir  1530 . 
     Accordingly, the above described embodiments provide a daisy chaining (for immersion fluid sharing) of multiple immersion cooling tanks  400  together (and potentially to a reservoir  1530 ) to allow the immersion fluid levels within the various tanks  400  to remain relatively equal. This prevents one tank  400  from having to be pulled offline due to the immersion fluid in that one tank falling below acceptable operating levels, while the other neighboring tanks  400  have more than sufficient amounts of fluid to continue operating. 
     H. Techniques for Controlling Vapor Pressure within an Immersion Cooling Tank 
     Another aspect of the disclosure involves providing a plurality of techniques for controlling and/or mitigating the buildup of pressure within the immersion tank in order to maintain the integrity of the tank (from high pressure vapor leakage, etc.) and provide other benefits. Generally, a first aspect of the concept involves use of an expansion lid with a bellows placed within or proximate to the tank cover to allow the overall system to be able to respond to fluctuations in pressure and particularly pressure build up by altering the internal volume of the immersion cooling tank. With the use of the bellows expansion lid, an increase in the volume of rising vapor pushes upwards against the bellows, and the bellows then moves upwards and increases the volume of the tank. Then, as the volume of the tank increases, the vapor pressure within the tank decreases). A second aspect of the concept involves providing a feedback control mechanism that increases the flow of the condenser fluid and/or reduces the temperature of the condenser fluid based on a detected buildup of pressure in the tank. A third aspect of the concept involves throttling the rate and/or amount of processing occurring within the tank. 
     As an introduction to these aspects of the disclosure, the above described two-phase immersion cooling system will vary in the amount of heat dissipation throughout operation of the various electronic components, such as servers  200 / 300 , causing increases and decreases in the amount of vapor mass present in the immersion cooling tank  400 . The changes in the mass of vapor within the tank  400  can create pressure fluctuations inside the tank enclosure. Given the headspace above the condenser line, the compression ratio of this vapor mass can easily be 2-3 times standard operating pressure. Such an increase in pressure will induce stress on the tank (effectively creating a pressure vessel), promote vapor diffusion through weaker seal points, and change the saturation temperature of the working fluid(s). 
     Also, an additional aspect of the disclosure addresses the engineering challenge of preventing the cooling fluid from escaping the immersion cooling tank when using a dielectric, such as 3M Novec fluid. The 3M Novec fluid is expensive, and excessive fluid loss thus negatively impacts the overall cost of the immersion-based cooling solution. According to one embodiment, the immersion cooling tank must maintain a robust seal to prevent fluid vapor from escaping the tank. As demand on the processing components increases and decreases resulting in the proportionate increase and decrease in heat dissipation, the amount of vapor versus liquid in the tank fluctuates. This fluctuation creates a change in internal tank pressure. 
     Existing tank based systems that involve pressure buildup typically resolve such buildup by introducing (1) a bellows system integrated into the tank, where the bellow&#39;s membrane inflates/expands during vapor pressure buildup to increase the overall system volume and thus mitigate the pressure increase, and (2) one or more pressure relief valves, which allows for only a slight build-up of pressure (typically less than 1 psi) and then vents excess pressure (vapor) into the surrounding room. This second alternative results in excessive amounts of fluid loss at great capital cost. The present disclosure recognizes that maintaining a substantially neutral pressure within the tank will reduce the fluid loss that results from vapor escaping weak areas within the tank seal. Also, the disclosure addresses the build-up of pressure without use of a pressure relief valve or increasing the volume of the cooling tank. 
     According to one aspect of the disclosure, a bellows system is installed in the tank at a specific location that allows for an “increase” in the available volume of the tank as the vapor pressure increases, in order to maintain a neutral pressure. The disclosure provides the optimal location of the bellows system to allow optimal functionality and protect the bellows system from external damage.  FIGS. 4, 5, and 8  each illustrate the location of a bellows expansion lid  490 / 890  within the inside area of the tank cover  480 . This first aspect of the solution involves providing a large enough bellows in a location within the upper volume of the immersion cooling tank  400  that is protected from damage during everyday operation.  FIG. 16  illustrates an example deployment of a bellows  1690  within a tank cover (interchangeably referred to as expansion lid  1680 ) of an immersion cooling tank  1600 , according to one or more embodiments. As shown by the inset drawing above the tank  1600 , the bellows  1690  is enclosed within the upper lid or cover  1680  of the immersion cooling tank  1600  above a perforated base section off the upper lid  1680  containing a plurality of holes  1630 . According to one embodiment, by enclosing the bellows  1690  within the tank cover  1680 , the surface area of the bellows  1690  can match the surface area of the tank volume, which provides a sufficiently large volume to manage the fluctuating vapor layer of rising vapor  1622  (illustrated as upper directional arrows). 
     The holes  1630  allow the rising vapor  422  to enter the bottom of the expansion lid  1680  and compress the bellows  1690 . The amount of compression is directly proportional to the amount of rising vapor within the upper tank volume and specifically the overflow amount of vapor that pushes upwards against the bellows  1690 . As further shown by the figure, the amount of vapor  422  within the upper tank volume can range from between a lower vapor line  1605  to an upper vapor line  1615  above the cooling liquid surface level  1625 . Each of these lines then correlates to a corresponding amount of deflection upwards by the bellows  1690 . As shown, lower vapor line  1605  correlates to first deflection position  1610  of bellows  1690 , while upper vapor line  1615  correlates to second deflection position  1620  of bellows  1690 . As indicated by the inset drawing, providing a side view of the lid assembly, the amount of rising vapor  1622  within the upper volume causes a corresponding compression or depression of the bellows  1690 , which is designed specifically to allow for this level of response to the buildup of vapor pressure within the tank volume. As further shown by the inset, and more clearly illustrated by  FIGS. 17A-B , described below, the tank cover  1680  includes a porous base above which the bellows  1690  is located. A total height of the tank cover  1680  is experimentally or analytically determined to allow for sufficient volume within the tank cover  1680  for the bellows  1690  to expand fully in low vapor pressure situations (e.g., when the tank is not being utilized) and then be compressed fully (at highest supported vapor pressure). 
     Thus, in at least the illustrated embodiment, the pressure control system comprises: a bellows expansion lid ( 1680 / 1690 ) positioned above the condensers  1660  within the immersion cooling tank  400 / 800  and which includes a bellows  1690  that, in response to an increase in pressure of the rising vapor above a threshold normal pressure, moves upwards (i.e., is compressed) into the lid  1680  of the immersion cooling tank  400 / 800  towards an upper position ( 1620 ) substantially eliminate the increase in pressure. The bellows  1690  within the expansion lid  1680  also moves downwards towards a base position ( 1610 ) in response to the amount of pressure within the tank  400  being reduced to below a low threshold pressure level. The increase and decrease in the bellows position is a gradual movement between these two positions ( 1610  and  1620 ), which directly correlates to the amount of vapor that is presently collected within the upper volume of the immersion cooling tank  400 / 800 . 
     The surface area of the bellows expansion lid  1680  can be substantially proximate to the surface area of the inner tank perimeter in one embodiment. In alternate embodiments, the surface area can be much smaller than the inner tank perimeter. It is appreciated that the actual shape and size of the bellows does not have to be similar to that of the inside of the tank cover, and much smaller bellows can be utilized effectively to mitigate pressure buildup. For example,  FIGS. 17A-17B  illustrate two different views of an implementation of a bellows system that provides multiple adjacent bellows within the tank cover, in accordance with one or more embodiments. In  FIG. 17A , tank  1700  is illustrated with the top cover of the lid  1780  removed to expose three adjacent bellows  1790 A-C. The perforated lower lid surface with a plurality of holes  1730  are indicated in the presentation of the middle bellows  1790 B. This split-bellows configuration represents an example vapor pressure control sub-system within an immersion cooling tank  1600 . The partitioning of the bellows  1790  is one possible implementation among many alternate options, and the presentation of three side-by-side bellows  1790  is solely for illustrative purposes of the particular embodiment. 
       FIG. 17B  presents a bottom view of the configuration of the tank cover  1780  to accommodate the three adjacent bellows  1790 A-C. As shown, the lower surface of the tank cover  1780  is divided into three adjacent segments/sections  1705 A-C. Each segment  1705  includes a perforated bottom panel with a plurality of holes  1730  to allow the vapor to pass through the surface and contact the lower surface of the bellows  1790 A-C located directly above the holes  1730 . Below the expansion lid  1780  is shown the condenser sub-units  1760 , similar to the configuration of immersion cooling tank  800  ( FIG. 8 ). 
     According to one aspect, by containing the bellows  1690 / 1790  within the tank cover (expansion lid  1680 / 1780 ), the bellows  1690 / 1790  is protected from damage that could occur during assembly, shipping, and normal day to day operation. It is important to note that this placement of the bellows  1690 / 1790  internal to the tank and specifically within the tank cover space/volume does not impact the overall footprint of the tank or impact the density of the resulting data center. 
     The second and third aspects of the pressure control solution are illustrated in part by  FIG. 18 . This implementation of the second and/or third aspects can be in addition to the above described use of bellows and/or a separate implementation altogether.  FIG. 18  provides example detection and control mechanisms and/or devices of an overall control system provided for one embodiment of immersion cooling tank  1600  ( FIG. 16 ). The schematic of  FIG. 18  illustrates a rack assembly of example first servers  200 , which are inserted in a side-by-side configuration within the rack (not specifically shown), and two internal power supply units (PSUs)  1805 , which can be the secondary components  830  referenced within the descriptions of  FIG. 8 , for example. PSUs  1805  can provide connectivity for providing a supply of power to the other components within immersion cooling tank  1600 . Generally, these mechanisms and devices of the control system can include, but are not limited to, operating condition detectors, including failure condition detectors, condenser fluid flow control valves, other control devices, and the bellows expansion lid  1680 . The mechanisms and/or devices collectively control various conditions that may exist or occur internal to the immersion cooling tank  1600  ( FIG. 16 ) during operation of the immersion cooling tank  1600  as a cooling system for submerged servers  200  and/or HDDs (not specifically shown) located above the liquid level  1825 . Specifically, The illustrated feedback and/or control mechanisms associated with controlling pressure within the immersion cooling tank  1600  include first differential pressure transducer  1810 , non-condensable purge valve  1830 , thermostatic control valve  1835 , second differential pressure transducer  1840  for condenser flow, and condenser inflow control valve  1845 . Additionally, at least second differential pressure transducer  1840  and condenser inflow control valve  1845  are communicatively coupled to controller  1850 . In at least one embodiment, controller  1850  can be a separate processing device. However, in an alternate embodiment, controller  1850  generally represents a processor of one of the servers  200  executing code of one or more feedback control modules  170  ( FIG. 1 ) to provide control logic. 
     According to one aspect of the disclosure, a plurality of techniques for controlling and/or mitigating the buildup of pressure within the immersion cooling tank is provided in order to maintain the integrity of the tank from high pressure vapor leakage and other pressure-induced problems. Referring specifically to  FIG. 18 , one embodiment provides a pressure control system within the two-phase heat transfer immersion cooling tank  1800 . As illustrated by  FIG. 18 , the system includes: a differential pressure transducer  1810 / 1840  that measures a differential pressure between a first vapor pressure internal to the immersion tank and a second pressure outside of the immersion tank; a condenser inflow control valve (or valve assembly)  1845  that controls a flow rate of condensation liquid within the condenser  1660  located within the immersion cooling tank  1800 ; and a controller  1850  or control logic  170  ( FIG. 1 ) that, in response to the measured differential pressure exceeding a pre-set threshold difference, triggers the condenser inflow control valve  1845  to increase a flow rate of the condensation liquid in order to reduce an amount of vapor (by faster condensation into a liquid condensate) within the immersion cooling tank  1800  and bring the measured differential pressure back to below the threshold differential pressure. 
     Another embodiment provides a pressure control system that includes: a cooling mechanism (not shown) that reduces a temperature of a portion of condensation liquid stored external to the immersion cooling tank  1800 ; and a controller  1850  or control logic  170  ( FIG. 1 ) that, in response to the measured differential pressure exceeding a pre-set threshold difference, triggers the condenser inflow control valve  1845  to: provide one or both of an increased flow rate of the condensation liquid and a lower ambient temperature of the condensation liquid, in order to increase vapor condensation due to a faster rate of heat absorption from the rising vapor and decrease the amount of vapor in the immersion cooling tank  1800 . The increase in the rate of vapor condensation reduces the amount of vapor  1622  ( FIG. 16 ) (by faster condensation into a liquid condensate) within the immersion cooling tank  1800  and thus reduces the associated vapor pressure. 
     In one or more embodiments, the pressure control system further includes: a condenser fluid flow controller  1850  that is connected to the differential pressure transducer  1840 . The differential pressure transducer  1840  is employed between the interior and exterior volumes of the cooling system in a feedback loop connected with the condenser fluid flow controller  1850 . The condenser fluid flow controller  1850  dynamically modulates (increases or decreases) flow of condensation fluid into the condensers, such that the vapor mass within the upper volume of the immersion cooling tank  1800  can be kept substantially constant or below a pre-set threshold value. The process substantially eliminates any detected pressure differential, and the control logic of the condenser fluid flow controller  1850  drives a differential pressure to the pre-determined value by increasing and/or decreasing the condenser fluid flow rate. Ideally, the pressure differential will be nearly zero at all times to prevent vapor escape. The condenser fluid flow controller  1850  then modulates coolant flow into the condensers, such that the vapor mass can be kept nearly constant, and thus eliminating any detected pressure differential. The control logic of the condenser fluid flow controller  1850  would continually seek to drive differential pressure to zero by increasing or decreasing coolant flow rate. 
     According to one embodiment, and as illustrated by feedback control loop  1900  of  FIG. 19 , the control logic  1915  of the condenser fluid flow controller  1850  ( FIG. 18 ) can include and/or be comprised of a proportional-integral-derivative (PID) algorithm coupled with a variable displacement solenoid valve  1845  ( FIG. 18 ) on the supply-side of a facility cooling loop. System feedback is provided by the differential pressure transducer  1810  coupled to the immersion cooling tank  1800 , with the control variable being the current inflow valve position  1925  of the solenoid valve  1845 . The current inflow valve position  1925  of the solenoid valve  1845  ( FIG. 18 ) is controlled by feedback provided by the differential pressure transducer  1810 , which compares the measured differential pressure to a threshold differential pressure  1910 . In the illustrated embodiment, the set point for the threshold differential pressure  1910  is indicated as 0 dP. A different set point value can be utilized within alternate embodiments. Control logic  1915  generates an inflow valve position request signal  1920  as the output. This output ( 1920 ) is communicated to the open/close control mechanism for solenoid valve  1845  ( FIG. 18 ) to change (i.e., granularly, gradually, and/or incrementally opening or closing) the current inflow valve position  1925  until a pressure equilibrium state is obtained within the immersion cooling tank  1800 . 
       FIG. 20  is a flow chart illustrating one embodiment of a method for controlling pressure within the immersion cooling tank  1600 / 1800  utilizing one or more of the above described aspects of the disclosure. Method  2000  begins at block  2002  at which the differential pressure of the interior and exterior of the tank  1800  is measured by one or more differential pressure sensors  1810 . At decision block  2004 , method  2000  includes controller  1850  determining whether the differential pressure exceeds a preset high pressure threshold. Method  2000  loops back to block  2002  when the differential pressure does not exceed the high pressure threshold. In response to the measured or detected differential pressure exceeding the pre-set high pressure threshold, controller  1850  opens the inflow valve  1845  to increase the rate of flow of condensation fluid through the condenser  1660  (block  2006 ). In one embodiment, a pump can be utilized within the feedback system, and controller  1850  then triggers the pump to increase the rate of flow of condensation liquid through the condenser. 
     Monitoring of the differential pressure continues and at decision block  2008 , controller  1850  determines whether the differential pressure is within the acceptable range of the high pressure threshold (e.g., below the preset high pressure threshold) following the initial feedback response. If the differential pressure is below the high pressure threshold, controller  1850  further determines at decision block  2010 , whether the differential pressure has fallen below a preset low pressure threshold (e.g., a negative differential pressure). In response to the differential pressure being below the preset low pressure threshold, controller  1850  then reduces the inflow rate in increments while monitoring the differential pressure until the differential pressure falls within the acceptable range (block  2012 ). This second check of the differential pressure and adjustment of the flow rate allows the controller to reduce the flow rate from a high flow rate that was introduced because of a positive differential pressure imbalance when the higher flow rate is no longer required, such that a regular or lower flow rate is sufficient for the control system&#39;s differential pressure equilibrium. Method  2000  then returns to block  2002 . 
     Returning to decision block  2008 , in response to the differential pressure not falling within the acceptable range of the high differential pressure threshold following the increased flow of condensation fluid, method  2000  can include a series of secondary measures to reduce the pressure within the immersion tanks. In one embodiment, the series of secondary measures can be triggered following expiration of a timer set to track the time elapsed since the increase in condensation fluid flow rate to address the high differential pressure readings within the tank. Thus, for example, the increased flow rate can be determined by empirical measurements or in the field testing to cause a percentage reduction in pressure sufficient to address the average build-up of pressure within the tank within time X following the increase in the flow rate. Thus, when the differential pressure readings do not fall below the high pressure threshold after time X following the increased flow rate, controller  1850  initiates the secondary measures to protect the overall integrity of the tank and/or the electronic devices within the tank. These secondary measures are optional and thus indicated with dashed lines. 
     Returning to the flow chart, at block  2014 , controller  1850  increases the flow rate incrementally to a maximum flow rate. Method  2000  then includes determining at decision block  2016  whether the system&#39;s differential pressure is still not within the acceptable range of the high pressure threshold. In response to the differential pressure still remaining above the high pressure threshold, controller  1850  transmits a signal to the processing servers to throttle the processing operations occurring on the servers (block  2018 ). This throttling of the processors reduces the amount of heat dissipation and by extension the amount of boiling and vaporization that occurs within the immersion cooling tank  1800 . The rate at which new vapor  1622  ( FIG. 16 ) is added to the upper volume of the immersion cooling tank  1800  is thus reduced. At block  2020 , method  2000  includes controller  1850  recording a failure condition and generating a failure report that can be transmitted to a terminal of an administrator or IT personnel. 
     Notably, one embodiment can also provide a release valve that is temporarily opened to release some of the vapor from the interior of the tank enclosure. However, this release valve can be associated with a return channel that allows the vapor to condense and return to a reservoir or to the tank volume as a cooling liquid condensate. This prevents the loss of vapor and by extension the cooling fluid required for the operation of the tank. The release valve can be controlled by a signal from the controller  1850 , where the controller  1850  generates the release valve signal only once a measured differential pressure passes a preset maximum differential pressure level. 
     The above described embodiments provide a plurality of techniques for controlling and/or mitigating the buildup of pressure within the immersion tank in order to maintain the integrity of the tank (from high pressure vapor leakage and/or other problems). One embodiment, illustrated by various example figures (e.g.,  FIGS. 16-17 ) provides for the use of bellows  1690  within the lid (cover)  1680  of the immersion tank  1600  to allow the immersion tank  1600  to respond to fluctuations in pressure, and particularly to pressure build up. Another embodiment, illustrated within the control structure of  FIGS. 18 and 19 , provides a feedback control mechanism that can respond to a detected buildup of pressure in the tank by (1) increasing the flow of the condensation fluid through the condenser and/or (2) reducing the temperature of the condensation fluid and/or (3) throttling the processing operations occurring at the servers within the tank, and/or (3) passing some of the excess vapor through a valve-controlled exterior liquid return piping system. 
     In the above described flow charts, one or more of the method processes may be embodied in a computer readable device containing computer readable program code such that a series of steps are performed when the computer readable program code is executed on a computing device. In some implementations, certain steps of the methods are combined, performed simultaneously or in a different order, or perhaps omitted, without deviating from the scope of the disclosure. Thus, while the method steps are described and illustrated in a particular sequence, use of a specific sequence of steps is not meant to imply any limitations on the disclosure. Changes may be made with regards to the sequence of steps without departing from the spirit or scope of the present disclosure. Use of a particular sequence is therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined only by the appended claims. 
     Aspects of the present disclosure are described above with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. Computer program code for carrying out operations for aspects of the present disclosure may be written in any combination of one or more programming languages, including an object oriented programming language, without limitation. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, such as a GPU, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, performs the method for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     As will be further appreciated, the processes in embodiments of the present disclosure may be implemented using any combination of software, firmware or hardware. Accordingly, aspects of the present disclosure may take the form of an entirely hardware embodiment or an embodiment combining software (including firmware, resident software, micro-code, etc.) and hardware aspects that may all generally be referred to herein as a “circuit,” “module,” or “system.” Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable storage device(s) having computer readable program code embodied thereon. Any combination of one or more computer readable storage device(s) may be utilized. The computer readable storage device may be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage device include: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage device may be any tangible medium that stores a program for use by or in connection with an instruction execution system, apparatus, or device. 
     I. Vertically-Oriented Immersion Server with Vapor Bubble Deflector 
     Each of the above described aspects of the disclosure, and the various associated embodiments illustrated and described, have been described with reference to example servers  200 / 300 , which represent a conventional design of a server that is utilized within a rack based data center or simply within a processing system. These conventional servers are typically originally designed to be air cooled by a fan within a dry environment. Thus, the immersion cooling aspects are fully applicable to these server designs where the HDDs, if included on the server, can be separated from the other heat generating processing devices, such as the processor and/or the memory modules, so that the HDDs are not immersed within the cooling fluid. As previously introduced, conventional HDDs are not designed to be submerged in a liquid medium. Thus, with the conventional liquid cooling of servers, the HDDs are either located remotely from the actual server and air cooled via use of a fan, or alternatively, according to the method provided by the present disclosure, these HDDs can be vapor cooled within the tank enclosure as the other operating components dissipate heat into and causes the vaporization of the cooling liquid located below the HDD cooling area. 
     Additional aspects of the disclosure provide for several novel designs of immersible servers that are specifically designed to have the processing components be submerged in a cooling liquid, and where provided, to have the physically connected HDDs be vapor-cooled within the same cooling vessel. 
       FIG. 21  generally provides an immersion-based liquid cooling system, which includes: a cooling vessel  2150  having an interior volume with a lower volume in which a cooling liquid ( 2112 ) is disposed and an upper volume in which one or more condensers  2160  can be provided; and a rack structure (not shown) for holding at least one vertically-oriented immersion server  2100  in an upright position relative to a directional orientation of the interior volume of the cooling vessel  2150 . The vertically-oriented immersion server  2100  represents a first design aspect, which provides an embodiment of a motherboard  2105  and processors  2110  of a multi-processor server  2100  that is designed to be liquid cooled by dissipating heat sufficient to cause the cooling liquid to boil. As shown by  FIG. 21 , motherboard  2105  of the example server  2100  includes two processors embedded thereon, namely first processor  2110 A and second processor  2110 B. Motherboard  2105  is submerged in cooling liquid  2112  within an immersion cooling vessel  2100 . The cooling liquid  2112  has surface layer  2125  that is vertically above the processors  2110 . Motherboard  2105  is placed in a vertically upright position within the cooling liquid, such that second processor  2110 B is positioned vertically above first processor  2110 A. As also shown by  FIG. 21 , motherboard  2105  is constructed with a vapor deflector  2120  positioned in between first processor  2110 A and second processor  2110 B. Vapor deflector  2120  angles away from the surface of motherboard  2105 , at an angle and a distance away from motherboard  2105  which enables sufficient deflection of rising vapor  2122 A (1) away from the upper portion of motherboard  2105  at which second processor  2110 B is located and (2) towards the surface  2125  of the cooling liquid  2112 . As first processor  2110 A operates (e.g., by executing program code or instructions), first processor  2110 A dissipates sufficient heat into the surrounding cooling liquid  2112  to cause the surrounding cooling liquid  2112  to boil. As the cooling liquid  2112  boils, the liquid evaporates and generates a plume of rising vapor bubbles  2122 , which bubbles upwards to the surface  2125  of the cooling liquid  2112 . Vapor deflector  2120  is designed with a specific length and is angled sufficiently to move the rising vapor bubbles  2122 A generated by heat dissipating from first processor  2110 A away from motherboard  2105 , such that the vapor bubbles  2122 A do not come into contact with any of the other submerged components at the upper portion of motherboard  2105  that are located vertically above the vapor deflector  2120  within the cooling liquid  2112 . As shown, heat dissipation from processing operations of second processor  2110 B also causes a boiling of the cooling fluid  2112 , which results in the generation of a second plume of rising vapor bubbles  2122 B. These rising vapor bubbles  2122  escape from the surface layer  2125  of the cooling liquid  2112  into the upper volume of the immersion cooling vessel  2150 . 
     Thus, the illustrative embodiment provides a server  2100  comprising: a printed circuit board (PCB) ( 2105 ) having a first surface at which one or more components are physically connected; a vapor bubble deflector  2120  having a first end physically abutting the first surface of the PCB ( 2105 ) and an opposing, second end that extends away from the first surface at an angle. The deflector segregates the first surface of the PCB ( 2105 ) into an upper segment and a lower segment when the server  2100  is placed in a vertically upright orientation. Generally, the server  2100  further includes a first heat dissipating component that is physically coupled to the lower segment of the PCB ( 2105 ) below the deflector  2120 ; and a second heat dissipating component that is physically coupled to the upper segment of the PCB ( 2105 ) above a point of contact between the first end of the deflector  2120  and the first surface of the PCB ( 2105 ). 
     As illustrated, in at least one embodiment, the first heat dissipating component can be a processor, i.e., first processor  2110 A, and the second heat dissipating component can also be a processor, i.e., second processor  2110 B. However, within a server specific implementation, the heat dissipating components can be any lower component on the server chassis that can dissipate sufficient heat to cause the localized boiling of the cooling liquid and subsequent generation of vapor bubbles below other components on the server chassis. For example, the described features are applicable to memory modules, SSDs, PSUs, and the like. Further, it is appreciated that the functionality described herein by utilization of the deflector applies to any type of electronic device (i.e., not necessarily a server) and that the heat dissipating components are not limited to computer and/or server based components and devices. With a standard electronic device, the PCB can be replaced by a base panel or back panel. 
     According to the illustrated embodiment, the server  2100  is designed for immersion-based liquid cooling by submerging the PCB ( 2105 ) with the first heat dissipating component ( 2110 A) and the second heat dissipating component ( 2110 B) into cooling liquid within an immersion cooling vessel  2150 , such that the cooling liquid surrounds the first and second heat dissipating components ( 2110 ) and absorbs heat being dissipated from the first and second heat dissipating components ( 2110 ). Consequently, portions of the cooling liquid surrounding the first heat dissipating component ( 2110 A) absorb sufficient heat to reach a boiling point temperate and evaporate to generate one or more rising vapor bubbles  2122 A that bubble to a surface of the cooling liquid  2112 . The vapor bubble deflector  2120  deflects the rising vapor bubbles  2122 A away from the second heat dissipating component ( 2110 B) towards the surface of the cooling liquid  2112 . The deflector is made of a material that is impervious to vapor bubbles. In one or more embodiments, the deflector is physically connected to the motherboard at the first end. 
     According to one embodiment, the server  2100  includes a casing (not shown) in which the PCB  2105  is placed and which is designed to orient the server  2100  in the vertically upright orientation within the immersion cooling vessel  2150 . By deflecting the rising vapor bubbles away from the second heat dissipating component, the vapor deflector  2120  enables a surface area of the second heat dissipating component ( 2110 B) to be exposed to and in full contact with the cooling liquid surrounding the second heat dissipating component ( 2110 B) in order to maximize heat absorption by the cooling liquid of heat being dissipated from the second heat dissipating component ( 2110 B). 
     In at least one embodiment, and as illustrated with the use of dashed boxes, the server  2100  can include at least one hard disk drive HDD  125  that is communicatively coupled to the processor and which is physically located vertically above the surface of cooling liquid and in a direct path of a rising plume of vapor (illustrated by the vertical arrows)  2122 C produced from the rising vapor bubbles  2122 . As shown, the lateral location of the HDDs  125  within the immersion cooling vessel  2150  can be set based on the direction of vertical rise of the vapor bubbles out of the cooling liquid. Thus, in order to maximize or take best advantage of the cooling effects of the rising vapor on the HDDs  125 , these HDDs are specifically positioned immediately above the surface areas of the cooling liquid at which the maximum amount of rising vapor bubbles escape upwards into the upper volume of the cooling vessel  2150 . Notably, the deflector  2120  causes a lateral displacement of the rising bubbles for the first processor  2110 A. As a consequence, there is also a lateral gap in-between the rising bubbles (on the left) of the second processor  2110 B and the rising bubbles of the first processor  2110 A. In addition to the selective placement of HDDs  125 , the selective location of sub-condensers  2160  in the upper volume can also be dictated by this lateral displacement of the rising bubbles, such that the sub-condensers  2160  are positioned at the horizontal location at which the maximum amount of vapor can impact the condensers as the vapor bubbles escape the cooling liquid surface and rises vertically upwards in the cooling vessel  2100 . 
     According to one aspect, the server  2100  can include a plurality of vertically-oriented heat dissipating components separated by a plurality of vapor bubble deflectors. Thus, one embodiment provides at least one additional vapor bubble deflector located vertically above one or more heat generating components. The at least one additional vapor bubble deflector shields at least one other heat dissipating component from vapor bubbles generated by boiling of cooling liquid surrounding the one or more heat generating components. 
     According to one or more embodiments, a plurality of bubble deflectors can be provided at different locations on the server or other submerged device. As described above, the bubble deflectors can be utilized as separators at the device level and located between individual components on and/or of the device. Additionally, according to another aspect, bubble deflectors can also be provided at and utilized on a component level, where the component level deflectors are designed to function as separators for vertical segments of the single component.  FIG. 21B  illustrates a second example of the vertically-oriented server configuration in which multiple vapor deflectors are provided to direct rising vapor bubbles away from upper portions of a single component, while the device level bubble deflectors and/or upper components that are submerged in cooling liquid.  FIG. 21C  then provides an example of a segmented high heat dissipating component that includes on-component deflectors as well as heat fins. Because of the similarity with  FIG. 21A , only the newly presented aspects of  FIG. 21B  will be described. Overlapping features of  FIGS. 21B and 21C  will be described together. In the illustrative embodiments of  FIGS. 21A and 21B , one or more angled deflector fins  2130  are shown extending from an exposed surface of a single component, separating the single component into a plurality of vertically-oriented segments  2160 . Specifically, in  FIG. 21B , first processor  2110 A and second processor  2110 B are shown having respective angled deflector fins  2130 , directly attached to and extending at an upwards angle away from the exposed surface of the respective processor  2110 A,  2110 B. The deflector fins  2130  represent component level deflectors, which act as a barrier to the upward path of rising vapor bubbles coming off the surface of the lower segment (e.g., first segment  2160 A, relative to deflector fin  2130 A) of the single component ( 2110 A) beneath the particular angled fin  2130 A. The deflector fins  2130  thus operate to channel the vapor bubbles  2122  generated at the lower segment of the particular component (e.g.,  2110 A,  2110 B) away from the upper segments of the particular component. Consequently, the deflector fins  2130  prevent bubble dryout for the upper portions of a single component. 
     As shown by  FIG. 21B , each device can comprise both device level and component level deflectors. In such an implementation, device level deflectors can be a different length or dimension from component level deflectors and/or the deflectors can be constructed from different materials and/or at different angles. Also, the spacing of the deflectors can be empirically or computationally determined to best allow for cooling of the components and segments thereof without the aforementioned bubble dryout occurring. Additionally, as shown by  FIG. 21C , even the component level deflectors are not necessarily symmetric. Thus deflector fins  2130  can be different lengths, dimensions, and at different angles. However, the design of the single components and of the overall device takes into consideration the bubble displacement caused by the lower placed deflectors and/or deflector fins in determination an optimal location, shape, size, and angle of each of the upper deflectors. 
     Additionally, in one embodiment and as illustrated by  FIG. 21C , high heat dissipating components, e.g., first processor  2110 A, can be designed having one or more heat fins  2140  extending outwards from the component ( 2110 A) to increase the surface area for cooling the high heat dissipating component. When the component includes the angled deflector fins  2130 , these heat fins  2140  are located immediately above a lower deflector fin (e.g., deflector fin  2130 A for heat fin  2140 A), in one embodiment, to enable the heat fin  2140 A to not be engulfed in bubbles formed at a lower segment  2160 A of the component ( 2110 A). The bubbles being generated from that heat fin ( 2140 A) are then directed by the upper deflector fin  2130 B or by the device level deflector  2120  ( FIG. 21A-21B ) located above the component ( 2110 A). 
     The above descriptions provide an immersion server that includes: a first surface that is exposed when the server is submerged within a cooling liquid; and at least one vapor bubble deflector physically abutting the first surface and extending away from the first surface at an angle. The deflector divides the first surface into an upper segment and a lower segment when the server is upright. When the server is submerged, the cooling liquid surrounding the lower segment absorbs sufficient heat to evaporate and generate vapor bubbles rising to the liquid surface. The vapor bubble deflector deflects the rising vapor bubbles away from the surface of the upper segment. This enables superior liquid contact with heat dissipating components at the upper segment and better cooling of those components. The deflector can be a device-level deflector separating two or more components or a component-level deflector separating a lower segment from an upper segment of a single component. 
     J. Immersion Server, Immersion Server Drawer, and Immersion Server Drawer-Based Cabinet 
       FIGS. 22-25  illustrate several additional design aspects of the disclosure, which directly address the core design of the server and cooling vessel for greater efficiency and usability of the various immersion cooling techniques described herein. Referring first to  FIGS. 22 and 23 , there are illustrated a motherboard and an information handling system designed and/or configured as a vertically-oriented liquid and vapor cooled immersion server (vLVCIS).  FIG. 24  then illustrates an immersion server drawer, while  FIG. 25  provides an immersion server drawer cabinet assembly. These designs collectively provide a method and system that enables cooling of functional components of an immersion server  2300  via an vaporization-condensation cycle utilizing a volatile (i.e., low boiling point) immersion cooling liquid provided within the immersion server drawer  2400 , while providing vapor cooling of HDDs of the immersion server  2300 . 
     According to a first aspect, illustrated by  FIG. 22 , example immersion server motherboard assembly  2200  comprises: a motherboard  2205  having a lower surface and an upper surface; a vertical arrangement of memory modules  2220  within receiving slots  2212  on the lower surface of the motherboard  2205 ; and at least one processor  2210  located on the upper surface of the motherboard  2205  and communicatively coupled to connectors of the receiving slots by signal traces (not shown) passing through the motherboard  2205  from the upper surface to the lower surface. According to one embodiment, the immersion server motherboard assembly  2200  further includes voltage regulators  2215  affixed to the upper surface of the motherboard  2205 . Additional components can also be included on motherboard  2205 . In one embodiment, the motherboard is a first printed circuit board (PCB). Also, in one embodiment, the memory modules  2220  include dual inline memory modules (DIMMs)  2222 . 
     As further illustrated by  FIG. 23 , the immersion server motherboard assembly  2200  can be physically and communicatively connected at one edge to a vertical panel  2330  to create immersion server  2300 . In one embodiment, the panel  2330  is perpendicular (e.g., approximately 90 degrees) to the motherboard  2205  and oriented vertically, such that the motherboard  2205  extends horizontally when the panel  2230  is placed in its vertical orientation, and a top portion of the panel  2330  extends vertically above the motherboard  2205  and the components located on the top surface of the motherboard  2205 . In alternate embodiments, the panel  2330  is oriented at an angle that is not necessarily a 90 degree angle relative to the motherboard  2205 , but which allows the panel  2330  to extend upwards above the topmost horizontal plane of the components of the motherboard. 
     As further illustrated, immersion server  2300  also includes one or more storage devices  2325 , which are physically connected to the top portion of the panel  2330  and extend above the components on the top surface of the motherboard  2205 . These storage devices  2325  are connected to and/or supported by the panel  2330 , which is a solid, rigid structure that is designed to support the weight of the one or more storage devices  2325 . In one embodiment, the panel  2330  can be a second PCB. The storage devices  2325  can be communicatively connected to the components on the motherboard  2205  via connecting traces or wires (not shown) extending on or through the panel  2330  to the motherboard  2205 . According to one embodiment, the storage devices  2325  are hard disk drives (HDDs), which can be similar to the HDDs  125  previously introduced. Alternatively, in one or more embodiments, the storage devices  2325  are designed with an exterior surface that facilitates vapor cooling within an immersion cooling vessel and are structurally designed to be attached to panel  2330  of an immersion server  2300 . 
     The design of the motherboard assembly  2200  and immersion server  2300  of  FIGS. 22 and 23  provides a vertically-oriented arrangement of functional components that enables a bifurcation of cooling, where lower components, such as the processors  2210  and the memory modules  2220 , are cooled via liquid cooling and upper components, such as the storage devices  2325 , are cooled via vapor cooling. Generally, the design and/or arrangement of the vLVCIS  2300  enables a first set of components attached to the motherboard  2205  (e.g., processor  2310 , memory modules  2220 , etc.) to be submerged in a cooling liquid and be liquid cooled during operation, while a second set of components (specifically the HDDs  2325 ) attached to the upper panel  2330  and extending above the motherboard assembly  2200  are air cooled by rising vapor generated as the cooling liquid evaporates. 
       FIG. 24  illustrates the second design aspect, which entails an immersion server drawer  2400  designed as one part of the vessel in which the immersion server is operated and cooled. Immersion server drawer  2400  includes an external impervious enclosure configured with opposing side walls, opposing front and rear walls and a bottom wall. The use of the term “wall” or “walls” to describe the sections of the drawer  2400  is meant solely to convey a location of the enclosure relative to a top and bottom and a front and rear of the immersion server drawer  2400  when in an upright position in which cooling liquid can be maintained within the bottom of the provided enclosure. The immersion server drawer  2400  has a depth or length dimension extending from the front wall to the rear wall. The length dimension is selected as a design parameter to be appropriately sized to receive one or more immersion servers  2300  in one of a first orientation (e.g., front to back) and/or a second orientation (e.g., left to right). The immersion server drawer  2400  also has a width dimension extending from a first side wall to a second side wall that is sized appropriately to receive one or more immersion servers in one of the first orientation and the second orientation. Finally, the immersion server drawer  2400  has a height dimension extending from the bottom to a top of the opposing side walls and appropriately sized to receive a single immersion server  2300  placed in an upright position. 
     As shown by  FIG. 24 , six immersion servers  2300  are placed within the enclosure created by immersion server drawer  2400 . The immersion servers  2300  are placed in an upright position, with the motherboard assembly  2200  having the processor  2210  and memory components  2220  ( FIG. 22 ) located within a bottom region of the enclosure, and the upper panel with the storage devices  2325  located closer to the top region of the enclosure. In the illustrated embodiment, the plurality of immersion servers  2300  are placed within the immersion server drawer  2400  in a side-by-side configuration along the depth of the immersion server drawer  2400 , adjacent to each other. One or more separators (not shown) can be provided within the enclosure to provide spacing between each immersion server  2300  and/or to provide a demarcation of where and in which orientation the immersion servers  2300  should be placed within the enclosure. In an alternate embodiment involving multiple immersion servers  2300 , the immersion servers  2300  can be placed in a side-by-side configuration along the width of the immersion server drawer. This configuration provides a wider immersion server drawer  2400 , and can include separators along the width dimension. In yet another embodiment, multiple immersion servers  2300  can be placed in both of the width dimension and the depth dimension of the immersion server drawer  2400 . In this latter configuration, separators can be provided in both the width and depth/length dimensions of the enclosure. 
     Immersion server drawer  2400  can include a dielectric cooling fluid, which is generally illustrated using a line representing the surface layer  2405 . The dielectric cooling fluid is placed within the lower portion of the enclosure of the immersion server drawer  2400  to a first cooling liquid level ( 2405 ) at which all components of motherboard assembly  2200  of immersion server  2300  would be submerged in the cooling liquid. In the illustrated embodiment, the cooling liquid level ( 2405 ) is below the storage devices  2325  of immersion server  2300 . As described herein, the processing and other components on the motherboard assembly  2200  of immersion server  2200  are submerged in cooling liquid and are liquid cooled. As further described herein, the cooling of the storage devices  2325  occurs via flow of rising vapor generated from vaporization of the dielectric cooling liquid, which creates a convectional cooling of the storage devices  2325  as the vapor passes over the surfaces of the storage devices  2325 . In one embodiment, the immersion server drawer  2400  further includes a handle  2420  disposed within a front (or outside) surface of the front wall  2415 . Also, in the illustrated embodiment, the inside surface of the front wall  2415  includes a rubber seal  2435  (see inset) that allows the immersion server drawer  2400  to be sealed air-tight when inserted into an immersion server drawer cabinet  2500  ( FIG. 25 ), which is designed specifically for insertion of immersion server drawer  2400 . As one aspect of creating this air-tight seal, immersion server drawer  2400  (and/or the cabinet) can include a clip or other locking mechanism  2430  that allows the immersion server drawer  2400  to be fixably inserted into the drawer cabinet  2500 . 
       FIG. 25  illustrates an example immersion server drawer (ISD) cabinet  2500 , which is a third server design aspect of the disclosure. The immersion server drawer cabinet  2500  is designed to hold one or more immersion server drawers  2400 , in which one or more immersions servers  2300  are partially submerged in a dielectric cooling fluid. According to at least one embodiment, the ISD cabinet  2500  is designed with specific dimensions to enable the immersion server drawer cabinet  2500  to fit within a standard IT rack, such that the immersion serer drawer  2500  can be mounted within the standard IT rack, including being mounted next to, or above or below, other servers within the IT rack. The immersion server drawer cabinet  2500  has an exterior casing  2505  and includes at least one drawer receptacle  2510  configured to accommodate insertion of an immersion server drawer  2400  therein. The example embodiment of  FIG. 25  illustrates a plurality of adjacent receptacles  2510 . When fully inserted into the drawer receptacle  2510 , the inside surface (with rubber seal  2435  ( FIG. 24 )) of the front wall of the immersion drawer  2400  compresses against the exterior front surface of the drawer receptacle  2510  to create an air-tight seal. Creation of the air tight seal prevents a loss of dielectric vapor during operation of the one or more immersion servers  2300  located within immersion drawer  2400 . A latching mechanism (e.g., latch  2430  ( FIG. 24 )) holds the immersion drawer  2400  in place to maintain the airtight seal. 
     The immersion server drawer cabinet  2500  includes a condenser  2560  located within an upper section of the ISD cabinet  2500  above the top of an inserted immersion server drawer  2400 . The condenser  2560  receives a flow of condensation fluid from an external fluid source and operates to condense rising vapor that evaporates off the surface of the dielectric cooling liquid as the one or more immersion servers  2300  dissipate heat. In one or more embodiments, the ISD cabinet  2500  includes a top cover  2580  within which can be disposed a bellows  2590  that modulates pressure build up due to the rising vapor. Each inserted immersion cooling drawer  2400  can be individually removed from the corresponding receptacle  2510  once the latching mechanism  2430  ( FIG. 24 ) is unlatched. 
     According to one aspect of the disclosure, at least one of the immersion server  2300 , the immersion cooling server drawer  2400 , and the immersion server drawer cabinet  2500  comprises a condensate liquid return system (not shown) that channels the condensed dielectric cooling liquid back to the lower enclosure of the immersion server drawer  2400  without the condensed dielectric liquid coming into contact with the HDDs  2325  ( FIG. 23 ) of the one or more immersion servers  2300  within the immersion cooling server drawer  2400 . 
     Accordingly, the above description provides an information handling system that includes an immersion server drawer (ISD) having an impervious enclosure which holds a volume of dielectric cooling liquid within/at the enclosure bottom. The ISD is configured with dimensions that enable insertion of liquid-cooled servers within the enclosure bottom. A plurality of liquid-cooled servers can be placed in a side-by-side configuration along one dimension of the ISD, with one or more heat dissipating components of the servers being placed below a surface layer of the cooling liquid. Submerged components of the immersion server are liquid-cooled, while the other heat generating components above the liquid surface are air cooled by rising vapor generated by boiling and vaporization of the cooling liquid. The ISD is placed in an ISD cabinet, which is configured with an upper condenser that allows for multi-phase cooling of the electronic devices placed within the immersion server drawer. The ISD cabinet can be rack-mountable. 
     K. Stand Alone Immersion Tank Data Center with Contained Cooling 
     The above introduced immersion based cooling solutions for cooling rack-mounted servers, as well as the newly designed immersion servers, drawers, and cabinets, are generally described as requiring a compatible condensation cooling system which includes a cooling infrastructure for channeling the condensation fluid to the exterior of the vessel. For example, the described condensation loops require an external transfer of condensation fluid utilizing a condensation fluid reservoir and/or facility-based cooling. The application of this cooling process finds applicability with large scale data centers with multiple immersion cooling tanks that can be efficiently cooled using a facility based cooling. 
     According to one embodiment, the SITDC includes a multi-phase heat transfer immersion cooling tank that enables direct cooling of information handling systems, such as data center servers, by submerging and operating the physical information handling systems in a volatile (i.e., low boiling point) liquid within the multi-phase heat transfer immersion cooling tank. 
       FIG. 26  illustrates one embodiment of a stand-alone immersion cooling data center (SICDC), which illustrates an immersion cooling tank, such as tank  400 / 500 , as the specific vessel. For continuity,  FIG. 26  is described with reference to components of the immersion cooling tank  400  introduced in  FIG. 4 . SITDC  2600  includes: an enclosed immersion cooling tank casing  405  that includes a tank volume; a dielectric fluid  412  within the bottom section of the tank volume; and one or more servers (e.g., server  200 / 300  of  FIGS. 2 and 3  or immersion server  2300  of  FIG. 23 ) within one or more server holding structures, such as a server rack. To simplify the illustration and description thereof, these servers are represented by first server  200 , which includes HDDs  125 , as illustrated. Each server  200  has one or more processing components and memory submerged within the dielectric fluid for liquid-based component cooling. The immersion cooling tank  405  further includes a condenser  2660 A located vertically above the plurality of servers ( 200 ) and in the direct path of rising dielectric vapor  422 . According to one embodiment, the walls of the tank volume are made of a material that is weather resistant and/or the external casing or walls are coated with a surface layer that is weather resistant. 
     According to one embodiment that incorporates the new immersion server design, the tank volume comprises one or more server drawers  2400  ( FIG. 24 ) with at least one vertically-oriented liquid and vapor cooled immersion servers (vLVCIS)  2300  ( FIG. 23 ) provided therein. The tank volume is air-tight and sealed to prevent escape of dielectric fluid from the inside of the tank. One embodiment provides the use of a specific rubber grommet  455  to allow for network and power cabling to access a wall of the tank volume without allowing the escape of any of the dielectric fluid. 
     In one or more embodiments, the condenser  2660 A is replaced with or is a passive heat exchanger, which includes the top lid  2680  of the tank being created with a heat conductive material and/or creating the lid with one or more heat conducting surface flanges  2682  as heat sinks protruding away from (i.e., extending downwards and/or upwards from) the surface of the top lid  2680 . The flanges  2682  increase the surface area of the passive condenser on which the rising vapor can interface and dissipate latent heat  2665  to the exterior surface of the tank&#39;s lid. Atmospheric air (i.e., wind) blowing outside of the tank across the external surface of the tank&#39;s top lid  2680  moves the hotter air away from the tank&#39;s lid  2680  and allows the tank&#39;s lid  2680  to continue to be able to absorb more heat being dissipated by the rising dielectric vapor  422 . The dielectric vapor  422  condenses on the flanges  2682  and/or the tank&#39;s lid  2680  generating a liquid condensate  442 , which falls back into the lower tank volume. The provided embodiment assumes that the amount of heat being dissipated from the operating servers and other components within the tank enclosure is low enough to allow for passive heat exchange with the surrounding atmospheric air. 
     The SITDC  2600  also includes an electrical connector  2670  and/or an access point for running an electrical cable through which electrical power can be supplied from an external electrical power supply source (not shown). The electrical connector  2670  allows for an external supply of power to be connected to the SITDC  2600  to power the plurality of servers  200 . 
     According to one or more embodiments, the SITDC  2600  also includes a power distribution unit (PDU)  425  located within the tank volume below a surface level  2635  of the dielectric fluid  412 . PDU  425  is utilized to provide power to the plurality of servers  200  and other components or devices operating within the tank volume via one or more power cables  2652 . In another embodiment, the tank volume includes an arrangement of a power distribution system that is embedded into the server rack, and which enables hot pluggable power to subsequent server chassis. The power distribution system can be configured as a Bus Bar type infrastructure. 
     According to an alternate embodiment, which is also illustrated by  FIG. 26 , the SITDC  2600  can further include components located external to the tank enclosure, including a heat exchanger  2625 , an optional pump  2630 , and external pipes  2655 ,  2657  interconnecting the components. The SITDC  2600  includes a first piping  2657  connecting the heat exchanger  2655  to the pump  2630  and connecting the pump  2630  to the intake pipes of an active condenser  2660 B (i.e., a condenser with a working fluid versus a passive heat exchanger, such as condenser  2660 A). A condensation fluid flows from the heat exchanger  2625  to the condenser  2660 B via the first piping  2657  at a flow rate controlled by the pump  2630  and/or an intake valve mechanism (not shown). The SITDC  2600  also includes a second piping  2655  connecting the condenser  2660 B to the heat exchanger  2625  and through which the condensing fluid flows from the condenser  2660 B to the heat exchanger  2625 . The heat exchanger  2625  can be located on an exterior wall of the tank enclosure to allow for transfer of heat to the surrounding atmosphere. Where included, the pump  2630  is also powered by the electrical power received via the electrical connector  2670 . In one embodiment, the pump  2630  and any other external component can be placed within an external casing (not shown) that can be bolted onto the side of the tank  2600 . 
     As one aspect of the disclosure, the SITDC  2600  further includes a controller  2650  located within the tank enclosure. The controller  2650  can be located below the surface layer  2635  of the dielectric fluid, in one embodiment. Additionally, in one or more embodiments, the controller  2650  can be one of, or functionality provided by one of, the immersion servers  200 / 300 . In one or more embodiments, the tank volume includes a low-level liquid sensor  2640  that is located below a threshold surface level of the dielectric liquid ( 412 ). In yet another embodiment, the tank volume includes a plurality of pressure regulating components, including a bellows  2690  located at the top of the tank volume and air pressure sensors  2645 - 2647 . The air pressure sensors  2645 - 2647  and the low-level liquid sensor  2640  are communicatively connected to the controller  2650  to provide feedback signals to the controller  2650 . 
     When implemented within a configuration that includes an external pump  2630  (described below) for controlling fluid levels or pressure gradients within the tank, controller  2650  can be communicatively coupled to the pump  2630 , and controller  2650  controls a rate at which the pump  2630  cycles the condensation fluid through the condenser  2660 . Thus, in one or more embodiments, in response to receipt of a high pressure signal from the air pressure sensors  2645 - 2647 , the controller  2650  triggers the pump  2630  to increase the cycle flow of the condensation fluid. In one or more embodiments, the controller  2650  also throttles the amount of processing being performed by one or more of the plurality of servers  200 / 300  to reduce an amount of heat dissipation within the tank volume. According to one embodiment, the controller  2650  includes a communication mechanism  2652  that enables communication of operating status data, including liquid levels, cooling efficiency, and average and high pressure data to an external monitoring device (not shown). In one embodiment, the communication mechanism  2652  also allows for receipt of externally-provided control parameters that can affect operation of one or more of the controller  2650 , the plurality of servers  200 / 300 , and other controllable devices or components of SITDC  2600 . 
     In one or more embodiments, the exterior enclosure of the SITDC  2600  includes at least one secure-access service panel door (not shown). The service access panel door allows access to the various components inside of the external enclosure, including the server tray, for servicing, repair, replacement, and/or re-configuring thereof. In yet another embodiment, the SITDC also includes a dielectric fluid intake replacement assembly with a fluid intake valve (not shown). The dielectric fluid intake replacement assembly can be utilized to replenish any dielectric fluid loss that occurs, as measured by the low-level liquid sensor  2640 . Finally, as illustrated, SITDC  2600  can include a handle  2675  by which a user can gain direct access to the interior of the tank by lifting the tank cover  2680  at the unhinged end. 
     The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the disclosure. The described embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated. 
     While the disclosure has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular system, device or component thereof to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims.