The power dissipation of integrated circuit chips, and the modules containing the chips, continues to increase in order to achieve continuing increases in processor performance. This trend poses a cooling challenge at both the module and system levels. Increased airflow rates are needed to effectively cool high power modules and to limit the temperature of the air that is exhausted into the computer center.
In many large server applications, processors along with their associated electronics (e.g., memory, disk drives, power supplies, etc.) are packaged in removable drawer configurations stacked within a rack or frame. In other cases, the electronics may be in fixed locations within the rack or frame. Typically, the components are cooled by air moving in parallel airflow paths, usually front-to-back, impelled by one or more air moving devices (e.g., axial or centrifugal fans). In some cases it may be possible to handle increased power dissipation within a single drawer by providing greater airflow, through the use of a more powerful air moving device or by increasing the rotational speed (i.e., RPMs) of an existing air moving device. However, this approach is becoming problematic at the rack level in the context of a computer installation or data center.
In some cases, the sensible heat load carried by the air exiting the rack is stressing the capability of the room air-conditioning to effectively handle the load. This is especially true for large installations with “server farms” or large banks of computer racks located close together. In such installations, liquid cooling (e.g., water cooling) is an attractive technology to manage the higher heat fluxes. The liquid absorbs the heat dissipated by the components/modules in an efficient manner, with the heat typically being transferred from the liquid to an outside environment, whether air or other liquid.
In one or more aspects, the shortcomings of the prior art are overcome and additional advantages are provided herein through the provision of an apparatus which includes a pump. The pump includes a rotating element, a volute housing and a bypass mechanism. The volute housing has a fluid inlet and a fluid outlet. In operational state of the pump, the rotating element rotates, drawing fluid through the fluid inlet of the volute housing, across the rotating element and expelling the fluid at a higher pressure through the fluid outlet of the volute housing. The bypass mechanism is integrated, at least in part, with the volute housing and exposes in nonoperational state of the pump, a bypass path through the volute housing allowing the fluid to pass from the fluid inlet to the fluid outlet thereof.
In another aspect, an apparatus is provided which includes a coolant-cooled cooling assembly for facilitating cooling at least one electronic component, and at least one coolant pump in fluid communication with the coolant-cooled cooling assembly to facilitate flow of coolant through the coolant-cooled assembly. The at least one coolant pump includes a rotating element, a volute housing and a bypass mechanism. The volute housing has a fluid inlet and a fluid outlet. In operational state of the pump, the rotating element rotates drawing the coolant through the fluid inlet of the volute housing, across the rotating element and expelling the coolant at a higher pressure through the fluid outlet of the volute housing. The bypass mechanism is integrated, at least in part, with the volute housing and exposes in nonoperational state of the coolant pump, a bypass path through the volute housing allowing the coolant to pass from the fluid inlet to the fluid outlet thereof.
In a further aspect, a method is provided which includes providing a coolant pump for a coolant-cooled cooling assembly to facilitate cooling at least one electronic component of an electronic system. The providing includes a rotating element and a volute housing having a fluid inlet and a fluid outlet, wherein in operational state of the coolant pump, the rotating element rotates, drawing coolant through the fluid inlet of the volute housing across the rotating element and expelling the coolant at a higher pressure through the fluid outlet of the volute housing. Further, providing the coolant pump includes providing a bypass mechanism integrated, at least in part, with the volute housing and exposing in nonoperational state of the coolant pump, a bypass path through the volute housing allowing the coolant to pass from the fluid inlet to the fluid outlet thereof.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention.
One or more aspects of the present invention are particularly pointed out and distinctly claimed as examples in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
In a conventional air-cooled data center, multiple electronics racks may be disposed in one or more rows, with the data center housing several hundred, or even several thousand, microprocessors within the electronics racks. Note that “electronics rack”, “rack unit”, “rack”, “information technology (IT) infrastructure”, etc., may be used interchangeably herein, and unless otherwise specified, include any housing, frame, support, structure, compartment, etc., having one or more heat-generating components of a computer system, electronic system, IT system, etc.
In an air-cooled data center, cooled air typically enters the data center via perforated floor tiles from a cool air plenum defined between a raised floor and a base or subfloor of the data center. Cooled air is taken in through air inlet sides of the electronics racks and expelled through the back or air outlet sides of the racks. Each electronics rack may have, for instance, one or more axial or centrifugal fans to provide inlet-to-outlet airflow to cool the electronic components within the one or more electronic systems of the electronics rack. The supply air plenum conventionally provides cooled and conditioned air to the air inlet sides of the electronics rack via perforated floor tiles disposed in a “cold” aisle of the data center, with the cooled and conditioned air being supplied to the plenum by one or more air-conditioning units, which are also typically disposed within the data center. Room air is taken into the air-conditioning units near an upper portion thereof. This room air may comprise, in part, exhausted air from the “hot” aisle(s) of the data center defined, for instance, by opposing air outlet sides of adjacent rows of electronics racks.
Due to ever-increasing airflow requirements through electronics racks of a data center, and the limits of air distribution within the typical data center installation, liquid-assisted cooling may be desirable in combination with conventional air-cooling.
Referring to
In addition to CCUs 130, the cooling system of coolant-cooled electronics rack 100 includes, by way of example, a rack-level coolant supply manifold 131, a rack-level coolant return manifold 132, and manifold-to-node fluid connect hoses 133 coupling rack-level coolant supply manifold 131 to one or more cooling assemblies within one or more electronic systems 110, and node-to-manifold fluid connect hoses 134 coupling the individual cooling assemblies within electronic systems 110 to rack-level coolant return manifold 132. Each CCU 130 is in fluid communication with rack-level coolant supply manifold 131 via a respective system coolant supply hose 135, and each CCU 130 is in fluid communication with rack-level coolant return manifold 132 via a respective system coolant return hose 136.
As illustrated, and by way of example only, a portion of the heat load of electronic systems 110 within electronics rack 100 may be transferred from the system coolant to, for instance, cooler facility coolant supplied via a facility coolant supply line 140 and a facility coolant return line 141 disposed, in the illustrated embodiment, in the space between a raised floor 101 and a base floor 102 of the data center housing the at least partially coolant-cooled electronics rack 100.
As explained further herein, cooling assemblies are provided, with one or more coolant-cooled heat sinks (or coolant-cooled cold plates) within electronic systems 110 of coolant-cooled electronics rack 100. The coolant-cooled heat sinks may be coupled to heat-generating electronic components of the electronic system, such as, for instance, processor modules, memory modules, etc. Heat is removed from the respective heat-generating electronic components via system coolant circulating through the coolant-cooled heat sinks within a system coolant loop defined by the coolant-conditioning units 130, rack-level manifolds 131, 132, and cooling assemblies within the individual electronic systems 110, which include the coolant-cooled heat sinks coupled to the electronic components being cooled. The system coolant loop and coolant-conditioning unit(s) may be designed to provide system coolant of a controlled temperature and pressure, as well as controlled chemistry and cleanliness to the coolant-cooled heat sinks coupled to the electronic components. In one or more embodiments, the system coolant may be maintained physically separate from the less-controlled facility coolant in, for instance, facility coolant supply and return lines 140, 141, to which heat may be ultimately transferred. Note that alternate heat dissipation implementations are also possible. For instance, the coolant-conditioning units 130 could be configured with one or more coolant-to-air heat exchangers to facilitate dissipating heat from the system coolant to an airflow passing through the coolant-conditioning units, for instance, from the air inlet side to the air outlet side of coolant-cooled electronics rack 100.
Recent server system designs and architectures continue to drive the need for enhanced cooling approaches and structures to be developed to cool, for instance, higher-power processor chips or modules. An example of high-power processor chips or modules which may benefit from active liquid cooling include the System z® Central Electronic Complex (CEC) processor modules offered by International Business Machines Corporation of Armonk, N.Y. By way of example, the electronic system to be cooled may be disposed in one or more horizontal drawer configurations comprising multiple distributed processor, single-chip modules (SCMs). The modules may be liquid coolant-cooled, such as water-cooled, via a liquid cooling system such as discussed above in connection with
By way of further explanation,
More particularly,
In addition to liquid-cooled heat sinks 320, liquid-based cooling system 315 includes multiple coolant-carrying tubes, including coolant supply tubes 340 and coolant return tubes 342 in fluid communication with respective liquid-cooled heat sinks 320. The coolant-carrying tubes 340, 342 are also connected to a header (or manifold) subassembly 350 which facilitates distribution of liquid coolant to the coolant supply tubes and return of liquid coolant from the coolant return tubes 342. In this embodiment, the air-cooled heat sinks 334 coupled to memory support modules 332 closer to front 331 of electronic system 110′ are shorter in height than the air-cooled heat sinks 334′ coupled to memory support modules 332 near back 333 of electronic system 110′. This size difference is to accommodate the coolant-carrying tubes 340, 342 since, in the depicted embodiment, the header subassembly 350 is at the front 331 of the electronics system and the multiple liquid-cooled heat sinks 320 are in the middle.
Liquid-based cooling system 315 comprises, in one embodiment, a pre-configured monolithic structure which includes multiple (pre-assembled) liquid-cooled heat sinks 320 configured and disposed in spaced relation to engage respective heat-generating electronic components. Each liquid-cooled heat sink 320 includes, in one embodiment, a liquid coolant inlet and a liquid coolant outlet, as well as an attachment subassembly (i.e., a heat sink/load arm assembly). Each attachment subassembly is employed to couple its respective liquid-cooled heat sink 320 to the associated electronic component to form the heat sink and electronic component (or device) assemblies depicted. Alignment openings (i.e., thru-holes) may be provided on the sides of the heat sink to receive alignment pins or positioning dowels during the assembly process. Additionally, connectors (or guide pins) may be included within the attachment subassembly to facilitate use of the attachment assembly.
As shown in
In one embodiment only, the coolant supply tubes 340, bridge tubes 341 and coolant return tubes 342 in the exemplary embodiment of
One drawback to an approach such as depicted in
Disclosed herein in one or more aspects are an apparatus and method of fabrication which include a pump, such as a coolant pump, with different fluid flow paths through the pump dependent on whether the pump is in an operational state or nonoperational state. By way of example, the pump includes a rotating element, a volute housing, and a bypass mechanism. The volute housing has a fluid inlet and a fluid outlet. In operational state of the pump, the rotating element rotates, drawing fluid through the fluid inlet of the volute housing, through or across the rotating element and expelling the fluid at a higher pressure through the fluid outlet of the volute housing. The bypass mechanism is integrated, at least in part, with the volute housing and exposes in nonoperational state of the pump, a bypass path through the volute housing allowing the fluid to pass from the fluid inlet to the fluid outlet thereof. The bypass path in the nonoperational state is a different fluid flow path through the pump than the flow path across the rotating element when in the operational state of the pump.
In one or more implementations, the bypass mechanism includes a spring disposed between the volute housing and the rotating element, and in the operational state, the higher pressure fluid pressurizes the rotating element within the pump, opposite the fluid inlet of volute housing forcing the rotating element to move towards the fluid inlet of the volute housing, compressing the spring between the volute housing and the rotating element. In the nonoperational state, the spring moves the rotating element away from the fluid inlet of the volute housing to expose the bypass path for the fluid to flow through the volute housing. In this manner, in the nonoperational state of such an implementation, the bypass path is defined between a surface of the rotating element and a surface of the volute housing.
In one or more other implementations, the bypass mechanism includes a valve disposed within the bypass path in the volute housing. In the nonoperational state, the valve transitions to allow fluid to pass through the bypass path from the fluid inlet to the fluid outlet of the volute housing. In one or more embodiments, the valve is a reed value directing fluid passing through the rotating element in the operational state of the pump to the fluid outlet of the volute housing, and in the nonoperational state, directing fluid passing through the bypass path to the fluid outlet of the volute housing.
In one or more implementations, the fluid outlet of the volute housing has an outlet flow diameter, and the bypass path includes a bypass flow diameter sized relative to the outlet flow diameter to minimize pressure drop through the pump when in the nonoperational state.
In one or more embodiments, the pump is one pump, and the apparatus further includes at least one other pump connected in series fluid communication with the one pump. The at least one other pump facilitating flow of the fluid through the bypass path when the one pump is in the nonoperational state. In one or more embodiments, the pump is a centrifugal pump, and the apparatus further includes a coolant loop, the pump being operatively coupled in fluid communication with the coolant loop to facilitate pumping of coolant through the coolant loop, where the fluid is the coolant.
As shown in
More particularly, in one or more implementations, pump 500 is a centrifugal pump for use in, for instance, a series redundant pump system, for instance, such as described above. In operational state, the impeller rotates about the shaft, drawing fluid (such as coolant) into the fluid inlet of the volute housing and expelling the fluid at a higher pressure through the fluid outlet of the volute housing. The higher pressure fluid is permitted to pressurize the side of the impeller opposite the volute housing fluid inlet, forcing the impeller to move along the shaft towards the volute housing fluid inlet, and compress the spring between the volute housing and the impeller. In the event the pump is disabled, the spring moves the impeller along the shaft away from the inlet region of the volute housing, creating or exposing the bypass path for the fluid to pass through the pump.
As noted,
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 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 “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”), and “contain” (and any form contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a method or device that “comprises”, “has”, “includes” or “contains” one or more steps or elements possesses those one or more steps or elements, but is not limited to possessing only those one or more steps or elements. Likewise, a step of a method or an element of a device that “comprises”, “has”, “includes” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features. Furthermore, a device or structure that is configured in a certain way is configured in at least that way, but may also be configured in ways that are not listed.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below, if any, are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention.