Apparatus and method for adjusting coolant flow resistance through liquid-cooled electronics rack(s)

Abstract

Apparatuses and methods are presented for adjusting coolant flow resistance through one or more liquid-cooled electronics racks. Flow restrictors are employed in association with multiple heat exchange tube sections of a heat exchange assembly, or in association with a plurality of coolant supply lines or coolant return lines feeding multiple heat exchange assemblies. Flow restrictors associated with respective heat exchange tube sections (or respective heat exchange assemblies) are disposed at the coolant channel inlet or coolant channel outlet of the tube sections (or of the heat exchange assemblies). These flow restrictors tailor coolant flow resistance through the heat exchange tube sections or through the heat exchange assemblies to enhance overall heat transfer within the tube sections or across heat exchange assemblies by tailoring coolant flow. In one embodiment, the flow restrictors tailor a coolant flow distribution differential across multiple heat exchange tube sections or across multiple heat exchange assemblies.

1 . A cooling apparatus for an electronics rack, the cooling apparatus comprising:
 an air-to-liquid heat exchange assembly for an electronics rack, wherein air moves through the electronics rack from an air inlet side to an air outlet side thereof and the air-to-liquid heat exchange assembly is configured to couple to the electronics rack at one of the air inlet side or the air outlet side thereof, and wherein the air-to-liquid heat exchange assembly comprises:
 an air-to-liquid heat exchanger comprising a coolant inlet plenum, a coolant outlet plenum, and multiple heat exchange tube sections coupled in parallel between the coolant inlet plenum and the coolant outlet plenum, each heat exchange tube section comprising a coolant channel having a coolant channel inlet and a coolant channel outlet, each coolant channel inlet being in fluid communication with the coolant inlet plenum and each coolant channel outlet being in fluid communication with the coolant outlet plenum, wherein system coolant flows through the multiple heat exchange tube sections in parallel; and 
 at least one flow restrictor associated with the multiple heat exchange tube sections, each flow restrictor of the at least one flow restrictor being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, the at least one flow restrictor tailoring coolant flow resistance through the respective heat exchange tube section to enhance heat transfer within the multiple heat exchange tube sections of the air-to-liquid heat exchanger. 
   
     
     
         2 . The cooling apparatus of  claim 1 , wherein the air-to-liquid heat exchange assembly further comprises multiple flow restrictors associated with the multiple heat exchange tube sections, each flow restrictor of the multiple flow restrictors being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, and wherein the multiple flow restrictors tailor a coolant flow distribution differential through the multiple heat exchange tube sections, the coolant flow distribution differential being tailored based on at least one of an air temperature differential across at least two heat exchange tube sections of the multiple heat exchange tube sections or location of the multiple heat exchange tube sections relative to the electronics rack when the air-to-liquid heat exchange assembly is coupled thereto. 
     
     
         3 . The cooling apparatus of  claim 1 , wherein the at least one flow restrictor facilitates defining different coolant flow resistances through at least two heat exchange tube sections of the multiple heat exchange tube sections. 
     
     
         4 . The cooling apparatus of  claim 3 , wherein the air-to-liquid heat exchange assembly further comprises multiple flow restrictors associated with the multiple heat exchange tube sections, each flow restrictor of the multiple flow restrictors being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, and wherein each flow restrictor of the multiple flow restrictors comprises a respective fixed diameter orifice, and at least two respective fixed diameter orifices of at least two flow restrictors of the multiple flow restrictors have different diameters. 
     
     
         5 . The cooling apparatus of  claim 3 , wherein the air-to-liquid heat exchanger assembly further comprises multiple flow restrictors associated with the multiple heat exchange tube sections, each flow restrictor of the multiple flow restrictors being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, and wherein the multiple flow restrictors tailor coolant flow resistance through the respective heat exchange tube sections to achieve a uniform coolant flow across the multiple heat exchange tube sections of the air-to-liquid heat exchanger. 
     
     
         6 . The cooling apparatus of  claim 1 , wherein the at least one flow restrictor comprises at least one adjustable flow restrictor, each adjustable flow restrictor of the at least one adjustable flow restrictor comprising a dynamically adjustable orifice opening size for dynamically adjusting system coolant flow resistance through the respective heat exchange tube section of the multiple heat exchange tube sections. 
     
     
         7 . The cooling apparatus of  claim 6 , wherein the dynamically adjustable orifice opening size of the at least one adjustable flow restrictor is one of passively controlled or actively controlled, and wherein the passively controlled adjustable flow restrictor comprises a temperature sensor for sensing airflow across the at least one respective heat exchange tube section and for adjusting the dynamically adjustable orifice opening size based on sensed temperature of the airflow, and the actively controlled adjustable flow restrictor comprises a pressure and temperature sensor for sensing pressure and temperature of system coolant at least one of the coolant channel inlet or the coolant channel outlet of the respective heat exchange tube section and for adjusting the dynamically adjustable orifice opening size based, at least in part, on sensed pressure and temperature of system coolant within the respective heat exchange tube section at the coolant channel inlet or the coolant channel outlet thereof. 
     
     
         8 . A cooling apparatus for a plurality of electronics racks, each electronics rack comprising a heat exchange assembly, the cooling apparatus comprising:
 a coolant distribution unit for supplying cooled system coolant to the heat exchange assemblies of the plurality of electronics racks;   a plurality of coolant supply lines, each coolant supply line being in fluid communication with the coolant distribution unit and the respective heat exchange assembly of a respective electronics rack of the plurality of electronics racks and facilitating supply of system coolant from the coolant distribution unit to the respective heat exchange assembly;   a plurality of coolant return lines, each coolant return line coupling in fluid communication the heat exchange assembly of a respective electronics rack of the plurality of electronics racks with the coolant distribution unit and facilitating return of exhausted system coolant from the respective heat exchange assembly to the coolant distribution unit, wherein system coolant circulates in a closed loop between the coolant distribution unit and the heat exchange assemblies via, at least in part, the plurality of coolant supply lines and the plurality of coolant return lines; and   a plurality of flow restrictors associated with at least one of the plurality of coolant supply lines or the plurality of coolant return lines, each flow restrictor being associated with a respective coolant line of the plurality of coolant supply lines or the plurality of coolant return lines for tailoring coolant flow resistance through the respective heat exchange assembly, and wherein the plurality of flow restrictors tailor coolant flow resistance through at least one of the plurality of coolant supply lines or the plurality of coolant return lines to enhance overall heat transfer through the heat exchange assemblies of the plurality of electronics racks.   
     
     
         9 . The cooling apparatus of  claim 8 , wherein the plurality of flow restrictors tailor a coolant flow distribution differential through the heat exchange assemblies of the plurality of electronics racks, the coolant flow distribution differential being tailored based on rack-level power consumption of the plurality of electronics racks. 
     
     
         10 . The cooling apparatus of  claim 9 , wherein the plurality of flow restrictors facilitate exhausting system coolant being in a super-heated, thermodynamic state. 
     
     
         11 . The cooling apparatus of  claim 8 , wherein the plurality of flow restrictors facilitate defining different coolant flow resistances through at least two heat exchange assemblies of the plurality of electronics racks. 
     
     
         12 . The cooling apparatus of  claim 8 , wherein at least one flow restrictor of the plurality of flow restrictors comprises at least one adjustable flow restrictor, each adjustable flow restrictor of the at least one adjustable flow restrictor comprising a dynamically adjustable orifice opening size for dynamically adjusting system coolant flow resistance through the respective heat exchange assembly. 
     
     
         13 . The cooling apparatus of  claim 12 , further comprising coolant pressure and temperature sensors associated with at least one of the plurality of coolant supply lines or the plurality of coolant return lines for sensing pressure and temperature of system coolant passing therethrough, wherein sensed pressure and temperature of the system coolant facilitates dynamic adjustment of at least one adjustable orifice opening size of the at least one adjustable flow restrictor. 
     
     
         14 . The cooling apparatus of  claim 8 , further comprising a controller for adjusting pump speed of a coolant pump of the coolant distribution unit based on total power consumption of the plurality of electronics racks, wherein the plurality of flow restrictors facilitate directing a higher system coolant flow to at least one heat exchange assembly of at least one electronics rack of the plurality of electronics racks with a higher power consumption than at least one other electronics rack of the plurality of electronics racks. 
     
     
         15 . The cooling apparatus of  claim 8 , wherein at least one heat exchange assembly of the heat exchange assemblies of the plurality of electronics racks comprises:
 an air-to-liquid heat exchanger comprising a coolant inlet plenum, a coolant outlet plenum, and multiple heat exchange tube sections coupled in parallel between the coolant inlet plenum and the coolant outlet plenum, each heat exchange tube section comprising a coolant channel having a coolant channel inlet and a coolant channel outlet, each coolant channel inlet being in fluid communication with the coolant inlet plenum and each coolant channel outlet being in fluid communication with the coolant outlet plenum, and wherein system coolant flows through the multiple heat exchange tube sections in parallel; and   at least one flow restrictor associated with the multiple heat exchange tube sections, each flow restrictor of the at least one flow restrictor being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, the at least one flow restrictor tailoring coolant flow resistance through the respective heat exchange tube section to enhance heat transfer within the multiple heat exchange tube sections of the air-to-liquid heat exchanger.   
     
     
         16 . The cooling apparatus of  claim 15 , wherein the at least one air-to-liquid heat exchange assembly further comprises multiple flow restrictors associated with the multiple heat exchange tube sections, each flow restrictor of the multiple flow restrictors being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, and wherein the multiple flow restrictors tailor a coolant flow distribution differential through the multiple heat exchange tube sections, the coolant flow distribution differential being tailored based on at least one of an air temperature differential across at least two heat exchange tube sections of the multiple heat exchange tube sections or location of the multiple heat exchange tube sections relative to the respective electronics rack. 
     
     
         17 . The cooling apparatus of  claim 15 , wherein the at least one flow restrictor facilitates defining different coolant flow resistances through at least two heat exchange tube sections of the multiple heat exchange tube sections. 
     
     
         18 . The cooling apparatus of  claim 15 , wherein the at least one flow restrictor comprises at least one adjustable flow restrictor, each adjustable flow restrictor of the at least one adjustable flow restrictor comprising a dynamically adjustable orifice opening size for dynamically adjusting system coolant flow resistance through the respective heat exchange tube section of the multiple heat exchange tube sections. 
     
     
         19 . A method of facilitating cooling of a plurality of electronics racks, each electronics rack comprising a heat exchange assembly, the method comprising:
 providing a plurality of coolant supply lines and a plurality of coolant return lines coupled in fluid communication between a coolant distribution unit and the heat exchange assemblies of the plurality of electronics racks, the coolant distribution unit supplying cooled system coolant for the heat exchange assemblies, wherein when operational, system coolant circulates in a closed loop between the coolant distribution unit and the heat exchange assemblies via, at least in part, the plurality of coolant supply lines and the plurality of coolant return lines; and   providing a plurality of flow restrictors associated with at least one of the plurality of coolant supply lines or the plurality of coolant return lines, each flow restrictor being associated with a respective coolant line of the plurality of coolant supply lines or the plurality of coolant return lines for tailoring coolant flow resistance through the heat exchange assembly of the respective electronics rack, and wherein the plurality of flow restrictors tailor coolant flow resistance through at least one of the plurality of coolant supply lines or the plurality of coolant return lines to enhance overall heat transfer through the heat exchange assemblies of the plurality of electronics racks.   
     
     
         20 . The method of  claim 19 , further comprising facilitating cooling of multiple heat exchange tube sections of the heat exchange assembly of at least one electronics rack of the plurality of electronics racks, wherein the heat exchange assembly of the at least one electronics rack comprises:
 an air-to-liquid heat exchanger comprising a coolant inlet plenum, a coolant outlet plenum, and multiple heat exchange tube sections coupled in parallel between the coolant inlet plenum and the coolant outlet plenum, each heat exchange tube section comprising a coolant channel having a coolant channel inlet and a coolant channel outlet, each coolant channel inlet being in fluid communication with the coolant inlet plenum and each coolant channel outlet being in fluid communication with the coolant outlet plenum, wherein system coolant flows through the multiple heat exchange tube sections in parallel; and   wherein the facilitating cooling comprises providing at least one flow restrictor associated with the multiple heat exchange tube sections, each flow restrictor of the at least one flow restrictor being associated with a respective heat exchange tube section of the multiple heat exchange tube sections and being disposed at one of the coolant channel inlet or the coolant channel outlet thereof, the at least one flow restrictor tailoring coolant flow resistance through the respective heat exchange tube section to enhance heat transfer within the multiple heat exchange tube sections of the at least one heat exchange assembly.