Method and apparatus for cooling electronic components

A modular fluid unit for cooling heat sources located on a rack, the modular fluid unit comprising: a heat exchanger in fluid communication a pump; and wherein the modular fluid unit is mountable within the rack and is configurable to be in fluid communication with a cold plate return manifold, a cold plate supply manifold, and an end-user fluid supply. A method for cooling electronic components in a rack, the method comprising: circulating a first liquid from a cold plate to one of a plurality of heat exchangers mounted within the rack; circulating a second liquid from a second liquid supply to the one of a plurality of heat exchangers; and transferring heat from the first liquid to the second liquid at the one of a plurality of heat exchangers.

BACKGROUND OF THE INVENTION

The presently disclosed method and apparatus are generally directed to a cooling unit for the cooling of electronic components. More particularly, the disclosed method and apparatus are directed to a modular fluid cooling unit.

One of the possibilities for cooling electronic components is the employment of arrays of air cooled heat sinks. Heat generated in an electronic component is conducted into the heat sinks and dissipated through the passage of a forced flow of ambient air within high aspect ratio flow channels between the heat sinks. Data centers with large computer and electronic systems vary greatly in airflow, raised floor height, chilled air availability and floor space. As a result, sometimes it is difficult to arrange air cooled machines in patterns that will allow for effective cooling. Each data center must be designed specifically to that data center's environmental conditions. In many cases, the machines must be spread out in order to prevent hot air recirculation. Other problems include impractical under-floor air flow rates, harsh environmental conditions, air conditioning power requirements, and the footprint of massive chillers. In future machines, as power levels per module increase, the combined heat dissipated by many machines in a confined workspace, whether they are independent or part of a large local area network (LAN), could exceed the capacity of the room air conditioning system in which the systems are placed. Refrigeration is an expensive alternative, but can also have similar problems.

The forgoing, in combination with current widespread trends in customer expectations for cooling computing systems which include: (1) redundancy, (2) versatility in installation and operating environment, (3) system expandability, (4) maintenance and system modifications performed without loss of system availability, and (5) reduction in the price per unit of computing capacity; creates a relatively untenable landscape and therefore the art is in need of improved cooling systems capable of resolving the need issues.

SUMMARY OF THE INVENTION

The disclosed apparatus relates to a modular fluid unit for cooling heat sources located on a rack, the modular fluid unit comprising: a heat exchanger in fluid communication a pump; and wherein the modular fluid unit is mountable within the rack and is configurable to be in fluid communication with a cold plate return manifold, a cold plate supply manifold, and an end-user fluid supply.

The disclosed system relates to cooling heat sources, the system comprising: a rack for holding electronic components; a cold plate located adjacent to a heat source located on the electronic components; a cold pate supply manifold in fluid communication with the cold plate; a cold plate return manifold in fluid communication with the cold plate; and a modular fluid unit mounted within the rack in fluid communication with the cold plate supply manifold, the cold plate return manifold and an end-user fluid supply.

Another embodiment of the disclosed system relates to cooling heat sources, the system comprising: a first rack for holding a modular fluid unit; a second rack for holding electronic components; a cold plate located adjacent to a heat source on the second rack; a cold pate supply manifold in fluid communication with the first cold plate; a cold plate return manifold in fluid communication with the first cold plate; and wherein the modular fluid unit mounted within the first rack is in fluid communication with the cold plate supply manifold, the cold plate return manifold, and an end-user fluid supply.

A further embodiment of the disclosed system relates to cooling heat sources, the system comprising: a rack for holding electronic components; an air fin and tube heat exchanger located adjacent to a heat source located on the electronic components; a supply manifold in fluid communication with the air fin and tube heat exchanger; a return manifold in fluid communication with the air fin and tube heat exchanger; a modular fluid unit mounted within the rack in fluid communication with the supply manifold, the return manifold and an end-user fluid supply.

The disclosed method relates to cooling electronic components in a rack, the method comprising: circulating a first liquid from a cold plate to one of a plurality of heat exchangers mounted within the rack; circulating a second liquid from a second liquid supply to the one of a plurality of heat exchangers; and transferring heat from the first liquid to the second liquid at the one of a plurality of heat exchangers.

DETAILED DESCRIPTION

Disclosed herein is a liquid cooling mechanism for electronic and/or computer systems using fluid from a central supply. Embodiments hereof are configured as a modular cooling apparatus that can be easily installed and removed from a rack. Further, the disclosed modular cooling apparatus is stackable (either vertically or horizontally), i.e. it can be placed in a redundant configuration with another modular cooling apparatus. In such a redundant configuration, one of the modular cooling apparatuses can be shut down, while the other modular cooling apparatus remains in operation. This allows for the servicing or replacing of one of the cooling apparatuses, without the necessity of shutting down the electronic and/or computer system.

Referring toFIG. 1, a schematic diagram of an embodiment of a disclosed fluid cooling system10is shown. A first valve18is in fluid communication with a fluid supply14and in fluid communication with a heat exchanger22. The first valve18may be any valve suitable to control the flow of a fluid through a flowpath of the heat exchanger22. The first valve18may comprise a proportional valve and electronic actuator. One commercially available proportional valve and actuator is made available by Johnson Controls, Milwaukee, Wis. (Part Number: VG7241GT+7125G). Of course other suitable proportional valves and actuators may be used. The fluid may be any suitable fluid that can be used in a heat exchanger. Some considerations for selecting a proper fluid are: heat absorption properties, heat dissipation properties, corrosion considerations, and leak effect considerations. In one embodiment, the fluid is chilled water. The temperature of the chilled water should be such that it will provide enough heat transfer for heated water coming from the heat sources, e.g. electronic components. In one embodiment, the proper heat transfer will occur if the temperature of the chilled water is between about 4 degrees Celsius and about 16 degrees Celsius. The fluid cooling system10comprises a first temperature sensor26configured to measure the temperature of the fluid between first valve18and the heat exchanger22. The temperature sensor may be selected from any of a number of temperature sensors suitable to measure a fluid used between the first valve18and heat exchanger22.

Still referring toFIG. 1, the heat exchanger is also in fluid communication with a fluid return30. The fluid cooling system10is configured such that a proper pressure differential between the fluid supply14and fluid return30will provide enough pressure to sustain the flow of the fluid from the fluid supply14through the valve18and a path of the heat exchanger22back to the fluid return30. In one embodiment, enough pressure to sustain a flow of fluid will be available if the fluid supply has a pressure difference between supply side and return side ranging from about 1 pounds per square inch (PSI) to about 30 PSI. In another embodiment, enough pressure to sustain a flow of fluid will be available if the pressure difference between supply side and return side ranges from about 3 PSI to about 15 PSI. The heat exchanger22is also in fluid communication with a cold plate supply manifold34. Measuring the pressure in the fluid flow between the heat exchanger22and cold plate supply manifold34is a pressure sensor62. The heat exchanger22may be any suitable heat exchanger that can be used to cool cold plates used to transfer heat from heat sources. In one embodiment, the heat exchanger22is an ITT Standard, Cheektowaga, N.Y., Brazepak model BP410-40. The heat exchanger22may be sized to handle heat loads up to about 20 kilowatt (kW) at about 20 gallons per minute (GPM). The heat exchanger22, may be a liquid heat exchanger, that is the fluids used to transfer heat within the heat exchanger22are liquid. Of course, the heat exchanger may be sized differently according to design specifications based on the cooling needs of the heat sources. A second temperature sensor42is configured to measure the temperature of the fluid between the heat exchanger22and the cold plate supply manifold34. In one embodiment the first and second temperature sensors26,42may be Omega, Stamford, Conn., resistance temperature detector (RTD) plug probe sensors with National Pipe Tapered Thread (NPT) fittings.

The cold plate supply manifold34is in fluid communication with one or more cold plates46. The one or more cold plates46are also in fluid communication with a cold plate return manifold50. The cold plate return manifold50may be in fluid communication with an optional reservoir54. The cold plate supply manifold34supplies fluid to the cold plates46. The fluid leaves the cold plates46and enters the cold plate return manifold50. The cold plates are located adjacent to one or more heat sources throughout the computer system. The manifolds34,50can be configured for numerous different flow paths to circulate across numerous cold plates46.

The cold plate return manifold50is in fluid communication with a pump58. The optional reservoir54is configured to provide enough pressure head and volume to prevent the pump58from cavitating. Of course, in some embodiments the manifold50may be configured to provide enough pressure head and volume to obviate the need for a reservoir54. The pump58is also in fluid communication with the heat exchanger22.

A controller28is a device that is configured to run a control algorithm which controls, based upon signals the controller28receives, the operation of the first valve18, and the operation of the pump58to satisfy the cooling requirements of the heat sources located throughout the computer and/or electronic system. Such signals include, but are not limited to signals received from the temperature sensors26,42, signals from the pressure sensor62, signals from the leak detectors66, and signals from a reservoir sensor. Therefore, the controller28is in operable communication with one or more the following non-exhaustive list of components: the first valve18; the first temperature sensor; the second temperature sensor; the pump58; and one or more leak detectors66located within the system10. Additionally the controller may be configurable to provide an alarm when certain values exceed or fall below programmed set points and/or if one or more of the leak detectors66detect a leak. In one embodiment, the controller28may be an MDA-RM card supplied by IBM, Poughkeepsie, N.Y.

The fluid used on the cold plate side of the fluid cooling system10may be any fluid suitable for cooling the cold plates46and transferring heat in the heat exchanger22. Such a fluid may include, but need not be limited to: water, propylene glycol, ethylene glycol or combinations thereof.

Several of the above recited components, discussed with respect toFIG. 1, comprise a modular fluid unit70. The modular fluid unit comprises: the first valve18; the heat exchanger22; the first temperature sensor26; the second temperature sensor42; the pump58and the controller28. Additionally, one or more leak detectors66will be located within the modular fluid unit74and be in operable communication with the controller28.

As shown inFIG. 2, the modular fluid unit may be configured to fit in a support structure for equipment needing cooling, such as a rack.FIG. 2shows a perspective view of an embodiment of a modular fluid unit70. A pump inlet72and a pump outlet76are shown in fluid communication with the pump58. The pump inlet72is also in fluid communication with a cold plate return manifold50(not shown in this view, refer back toFIG. 1). The pump outlet76is in fluid communication with a heat exchanger first inlet80, which in turn is in fluid communication with the heat exchanger22. The heat exchanger22is also in fluid communication with a heat exchanger first outlet84, a heat exchanger second inlet88and a heat exchanger second outlet92. The heat exchanger first outlet84is in fluid communication with a cold plate supply outlet86, which in turn is in fluid communication with the cold plate supply manifold34(not shown). The pressure sensor62is configured to measure the pressure between the heat exchanger first outlet84and the cold plate supply manifold34. In one embodiment, the pressure sensor62may be a pressure switch that is triggered if a loss of pressure is detected, e.g. when the pressure falls below 10 psi, the pressure switch will indicate a problem. There is also a second temperature sensor42configured to measure the temperature between the heat exchanger first outlet84and the cold plate supply manifold34. The fluid supply14(not shown) is in fluid communication a fluid supply inlet96. The fluid supply inlet is in fluid communication with the first valve18. The first valve18is in fluid communication with the heat exchanger second inlet88. The first temperature sensor26is configured to measure the temperature between the first valve18and the heat exchanger second inlet88. The heat exchanger second outlet92is in fluid communication with a fluid return outlet100. The modular fluid unit70also comprises a drip pan104, which is configured to retain any liquid condensate or liquid that may leak from other components in the modular fluid unit70. One leak detector66is shown partially obstructed by the fluid return outlet100. Another leak detector may be located near the pump58(not shown in this view) or wherever a leak detector is desired. A leak detector is employed to enhance probability that a leak is detected early. It will be understood, however, that a single leak detector can be used and may be placed in a low spot of the drip pan104. The modular fluid unit70can be configured to be mountable at any storage rack, and in one embodiment is sized to be mountable in a 22 inch by 32 inch rack that has four rack units (U) (each rack unit is 1.75 inches) of height. The pump inlet72, cold plate supply outlet86, fluid supply inlet96and fluid return outlet100may all comprise quick connect couplings for fast coupling and de-coupling with little or no leaking of the fluid.

FIG. 3shows a perspective view of the modular fluid unit70with a cover108over most of the components. The drip pan104and cover108may be fabricated from sheet metal or other material capable of performing the duties of each of these components, specifically supporting the other components of the unit70, providing a cover to the other components of the unit70, providing noise and vibration reduction and containing leaks to some degree.

FIG. 4shows a perspective view of a rack112with a first modular fluid unit70, and a redundant modular fluid unit270, both located at the bottom of the rack112. Having a redundant modular fluid unit270allows for passive and/or active control switching so that either one of the two modular fluid units70,270can be removed and serviced while the other modular fluid unit keeps the cooling system operating. For clarity, the rack112is shown without any computer components, electronic components, or cold plates installed. The cold plate return manifold50is shown attached to the rack112. A portion of the cold plate supply manifold34can be seen through an opening in the rack112. The cold plate return manifold is in fluid communication with the reservoir54. In fluid communication with the cold plate return manifold50is one or more cold plate return connectors116. Each of the cold plate return connectors are in fluid communication with one or more cold plates46(not shown). There are two outlets120,124from the cold plate return manifold50, a first outlet120and a second outlet124. Each of the outlets are in fluid communication (not shown) with one of the modular fluid units70,270. For instance, the first outlet120may be in fluid communication (not shown) with the pump inlet72of the modular fluid unit70, and the second outlet124may be in fluid communication (not shown) with the pump inlet272of the other modular fluid unit270. The cold plate return manifold50also has a capped end121. The cap may be removed and fluid may be added at the capped end121.

FIG. 5shows a view of the rack112where the cold plate supply manifold34is plainly visible. Although mostly obstructed, a portion of the cold plate return manifold50can be seen through an opening in the rack112. The cold plate supply manifold34is shown attached to the rack112. In fluid communication with the cold plate supply manifold34is one or more cold plate supply connectors128. Each of the cold plate supply connectors is in fluid communication with one or more cold plates46(not shown). There are two inlets132,136from the cold plate supply manifold34, a first outlet132and a second outlet136. Each of the inlets132,136are in fluid communication (not shown) with one of the modular fluid units70,270. For instance, the first outlet132may be in fluid communication (not shown) with the cold plate supply outlet86, and the second outlet136may be in fluid communication (not shown) with a cold plate supply outlet286of the modular fluid unit270. Quick connect couplings on the manifolds34,50permit convenient attachment/detachment of rack hoses without loss of liquid. The cold plate supply manifold34also has a capped end122. The cap may be removed and fluid may be added at the capped end122.

In one embodiment, the modular fluid unit can be stacked in a rack separate from other racks which have components that need to be cooled. The modular fluid unit can then supply cooling water to the other racks.

In another embodiment, the modular fluid unit can be used to supply cooling water to an air fin and tube heat exchangers, which can be used to cool the air within an electronics rack, instead of using a cold plate.

The disclosed modular fluid control units are mounted within a rack, as opposed to being a stand alone unit, occupying floor space. Since the modular fluid control units are installed in the rack, the modular fluid control units can be used in any layout regardless of what type of raised floor, if any, the racks are located on. Since the modular fluid control units are modular, they can be quickly removed and installed into racks, thus limiting machine downtime. Additionally, since two fluid control units can be used in one rack, it is possible to run these units redundantly. In such a configuration, one of the two fluid control units can be serviced without having to shut down the computer system. The modular fluid control units can be configured to weigh less than about 75 pounds, thereby qualifying the modular fluid control units for only a two man lift.

Although it will be apparent to one of ordinary skill in the art from the foregoing, it is pointed out that from a high level perspective, the method disclosed may be illustrated in the embodiment of the method shown inFIG. 6. At process block150, a first fluid is circulated from a cold plate to one of a plurality of heat exchangers. At process block154, a second fluid is circulated from a second fluid supply to a one of a plurality of heat exchangers. At process block158, heat is transferred from the first fluid to the second fluid at one of the plurality of heat exchangers.

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.

While the disclosed apparatus and method has been described with reference to a preferred embodiment, 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 disclosed apparatus and method. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosed apparatus and method without departing from the essential scope thereof. Therefore, it is intended that the disclosed apparatus and method not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this disclosed apparatus and method, but that the disclosed apparatus and method will include all embodiments falling within the scope of the appended claims.