Cooling distribution unit flow rate
In some examples, a system may include a plurality of cooling distribution units (CDUs) to control cooling of a plurality of computing devices based in part on average differential pressure between a supply and return for each of the plurality of CDUs, temperature of coolant in a loop flowing between each of the plurality of CDUs and computing devices, and facility valve position for each of the plurality of CDUs, wherein one CDU of the plurality of the CDUs is nominated lead CDU and broadcasts flow rate to the plurality of CDUs to follow.
1. A system comprising:
a plurality of cooling distribution units (CDU's) to control cooling of a plurality of computing devices based in part on average differential pressure between a supply and return for each of the plurality of CDU's, temperature of coolant in a loop flowing between each of the plurality of CDU's and computing devices, and facility valve position for each of the plurality of CDU's,
wherein one CDU of the plurality of the CDU's is nominated lead CDU by the plurality of CDU's and broadcasts a flow rate to the plurality of CDU's to follow, and
wherein each CDU of the plurality of CDU's includes the capability to be a lead CDU.
2. The system of claim 1 , wherein the lead CDU determines the flow rate based on the average differential pressure between the supply and return for each of the plurality of CDU's.
3. The system of claim 2 , wherein the lead CDU adjusts the flow rate, based on a change to the average differential pressure, and broadcasts the adjusted flow rate to the plurality of CDU's.
4. The system of claim 1 , wherein each of the plurality of CDU's varies the flow rate as an offset of the broadcasted flow rate.
5. The system of claim 4 , wherein the offset is a range set by the lead CDU.
6. The system of claim 5 , wherein the range is +/−15% of the broadcasted flow rate.
7. The system of claim 1 , wherein each CDU of the plurality of CDU's includes the same control logic.
8. The system of claim 1 , wherein in response to a failure of the lead CDU, the plurality of CDU's minus the failed CDU nominate a new lead CDU.
9. The system of claim 1 , wherein in response to a CDU's facility valve position in a greater than or equal to 60% open position, the CDU decreases the CDU's flow rate, by an offset percentage, below the broadcasted flow rate.
10. The system of claim 1 , wherein in response to a CDU's facility valve position in a less than or equal to 40% open position, the CDU increases the CDU's flow rate, by an offset percentage, above the broadcasted flow rate.
11. A method comprising:
reading, with a cooling distribution unit (CDU), a local facility valve position;
reading, with the CDU, a lead CDU's broadcasted flow rate;
in response to the local facility valve position open to less than or equal to a lower range, increasing, with the CDU, the CDU's flow rate above the lead CDU's broadcasted flow rate;
in response to the local facility valve position open to greater than or equal to an upper range, decreasing, with the CDU, the CDU's flow rate below the lead CDU's broadcasted flow rate; and
in response to the local facility valve position open to less than the upper range and greater than the lower range, setting, with the CDU, the CDU's flow rate to the lead CDU's broadcasted flow rate.
12. The method of claim 11 , further comprising:
reading, with the lead CDU, the lead CDU's local facility valve position;
in response to the lead CDU's local facility valve position open to greater than or equal to the upper range, increasing, with the lead CDU's, the lead CDUs broadcasted flow rate;
in response to the lead CDU's local facility valve position open to less than or equal to the lower range, decreasing, with the lead CDU, the lead CDU's broadcasted flow rate; and
in response to an adjustment to the lead CDU's broadcasted flow rate, broadcasting, with the lead CDU, an adjusted flow rate.
13. The method of claim 11 , wherein the plurality of CDUs include at least two CDUs.
14. The method of claim 11 , wherein the lower range of the local facility valve position is equal to or less than forty percent open.
15. The method of claim 11 , wherein the upper range of the local facility valve position is equal to or greater than sixty percent open.
16. The method of claim 11 , wherein the lead CDU sets the lead CDU's flow rate to a value different than the lead CDU's broadcasted flow rate to maintain average differential pressure.
17. A non-transitory machine-readable storage medium encoded with instructions executable by a processor, the non-transitory machine-readable storage medium comprising, instructions to:
nominate one CDU of a plurality of CDU's to lead CDU by the plurality of CDU's, wherein each CDU of the plurality of CDU's includes the capability to be a lead CDU;
read a local facility valve position;
read a broadcasted flow rate from the lead CDU;
set a flow rate to the broadcasted flow rate;
in response to a reading of the local facility valve position passing an upper limit, set the flow rate to a value at an offset lower than the broadcasted flow rate;
in response to the reading of the local facility valve position passing a lower limit, set the flow rate to a value at an offset higher than the broadcasted flow rate; and
in response to a failure of the lead CDU, nominate a new lead CDU from the plurality of CDU's minus the failed CDU.
18. The non-transitory machine-readable storage medium of claim 17 , further including instructions to:
in response to the nomination to the lead CDU, set the broadcast flow rate based in part on average differential pressure and a secondary loop coolant temperature.
19. The non-transitory machine-readable storage medium of claim 18 , further including instructions to:
broadcast to the plurality of CDU's the broadcasted flow rate.
20. The non-transitory machine-readable storage medium of claim 17 , wherein the upper limit is a 60% open position and the lower limit is a 40% open position.