Data Center Air Circulation

Abstract

A method for cooling electronic equipment can include flowing cooling air across a plurality of computer units and into a common warm air plenum located at a first end of the computer units; flowing air from the warm air plenum through one or more cooling units, and into an area located at a second end of the computer units; and controlling a flow rate of air out of the warm air plenum to maintain a predetermined pressure differential between the second end of the computer units and the first end of the computer units.

1 - 17 . (canceled) 
     
     
         18 . A method for cooling electronic equipment, comprising:
 flowing cooling air from a human-occupiable workspace into a computer rack and across a plurality of computer units supported by the computer rack and into a common warm air plenum located at a first end of the computer units;   flowing air from the warm air plenum, through one or more cooling units, and into the human-occupiable workspace adjacent a second end of the computer units that is open to the human-occupiable workspace during operation of the one or more cooling units to receive the flow of cooling air from the human-occupiable workspace; and   controlling a flow rate of air out of the common warm air plenum to maintain a predetermined pressure differential of approximately zero between the human-occupiable workspace and the common warm air plenum.   
     
     
         19 . The method of  claim 18 , wherein the computer units are serviceable from at least one of the first end or the second end. 
     
     
         20 . The method of  claim 18 , further comprising:
 measuring a pressure at the second end of the computer units with a pressure sensor in a workspace;   measuring a pressure at the first end of the computer units with a pressure sensor in the warm air plenum; and   determining a differential pressure between the first and second ends of the computer units.   
     
     
         21 . The method of  claim 20 , further comprising:
 determining that the differential pressure between the first and second ends of the computer units is greater than approximately zero; and   based on the determination, adjusting a variable speed drive electrically to a plenum exhaust fan.   
     
     
         22 . The method of  claim 18 , wherein controlling the flow rate of air out of the common warm air plenum comprises controlling the speed of a plurality of plenum exhaust fans. 
     
     
         23 . The method of  claim 22 , wherein the plurality of plenum exhaust fans are connected to a single control point for the common warm air plenum. 
     
     
         24 . The method of  claim 18 , further comprising controlling the flow of cooling air across a particular computer unit with one or more circulation fans, positioned external to the common warm air plenum, and controlled to maintain a set temperature rise across the computer units. 
     
     
         25 . The method of  claim 24 , wherein the set temperature rise is more than about 20 degrees Celsius. 
     
     
         26 . The method of  claim 24 , wherein each computer unit of the plurality of computer units is paired with at least one circulation fan that is mounted to the computer unit, the method further comprising:
 controlling a flow of cooling air across each computer unit with the paired at least one circulation fan based on a particular heat load associated with each computer unit.   
     
     
         27 . The method of  claim 26 , wherein at least two of the particular heat loads associated with respective computer units are different. 
     
     
         28 . A system for providing air circulation to rack-mounted computers, the system comprising:
 a plurality of rack-mounted computer units, each computer unit having a front end near a human-occupiable workspace;   a plurality of circulation fans mounted in proximity to the computer units to draw air across the computer units and into a warm air plenum adjacent a back end of the computer unit; and   one or more warm air plenum fans controlled to maintain a set pressure differential between the workspace and the warm air plenum of approximately zero.   
     
     
         29 . The system of  claim 28 , further comprising one or more cooling coils controlled to cool air provided from the warm air plenum to the workspace. 
     
     
         30 . The system of  claim 28 , further comprising a control system controlling the speed of the warm air plenum fans. 
     
     
         31 . The system of  claim 30 , further comprising control systems associated with each of the plurality of circulation fans, the circulation fans controlled to maintain a set temperature rise across each of the computers units. 
     
     
         32 . The system of  claim 31 , wherein the control systems control the plurality of circulation fans to maintain the set temperature rise based on a heat load associated with each of the plurality of computer units. 
     
     
         33 . The system of  claim 31 , wherein the control systems associated with each of the plurality of circulation fans do not communicate with the control system controlling the speed of the warm air plenum fans. 
     
     
         34 . The system of  claim 28 , wherein the plurality of rack-mounted computer units are located across an open side wall of the warm air plenum. 
     
     
         35 . The system of  claim 28 , wherein the rack-mounted computer units comprise a plurality of horizontal motherboards mounted in a vertical stack. 
     
     
         36 . The system of  claim 28 , wherein the plurality of circulation fans are located to draw air across the computer units and then through power supplies associated with the computer units. 
     
     
         37 . The system of  claim 36 , wherein the plurality of circulation fans are mounted to the power supplies.