How is ACS being deployed in data centers today?

Don Mitchell

The purpose of this message is to collect input from ACS vendors (DoorHX, cold plate, immersion) on current methodology and issues associated with connecting liquid cooled solutions to medium-large scale data centers using slab floor designs.  Please respond with any insights (please advise if you prefer anonymity).


  • In a 2MW-10MW slab floor data center, what source of cooling liquid would you connect to
    • Direct to existing loop, using cooling loop liquids, temperatures, dP
    • Direct to existing loop, using a CDU/HX to align temperatures, pressures and dP  (including CDUs integrated with ITE solutions)
    • Independent loop to external HX
  • In a slab floor data center, how would you connect to the liquid distribution loop  (select or comment on all that apply)
    • flexible drop (hose) vs fixed pipe
    • balancing valve vs no balancing valve
    • Thread connection, flange connection, grooved coupling solution, braised/fused connection
      • Does the current connect solution meet your needs


The Advanced Cooling – Facilities (ACF) subproject of OpenComputeProject continues  - developing guidance, reference designs, and case studies around deployment of liquid cooled IT in data centers.

A “Map” of the ACF vision is attached at the bottom of this message.  We have been covering a lot of foundational discussions in preparation for delivery of reference designs and guidance


Discussions on Tuesday, 17 November will include TheUptimeInstitute addressing Tier rating impacts as well as continued discussions on use of CDUs and HX

Future discussions will include

  • Connection types – what is the best method to connect ACS to FWS
  • Prefab Perfection – inviting design leaders and members of BIM solutions to discuss practicality of defining “perfect prefab” – offsite constructed, prefabd solutions that require no jobsite adaptationl


Would greatly value your insights and participation. 

Please advise if you object to being added to the mailing/invite list.


OpenComputeProject Tech Week was very successful, a lot of key insightsl.  Sessions are recorded.  Go back and listen if you were not able to attend


Data Centers are evolving to add liquids to improve performance and efficiency

Thanks for leading the change


Kind Regards


Don Mitchell

John Menoche, P.E.


Subproject Co-Leads for Advanced Cooling - Facilities


To get involved: 

1) Please become an OCP member and join the ACF Mailing List

2) Get familiar with the details on the Sub-Project on the ACF Wiki

3) Check our Project Calendar for more info. Call Info and agenda will be published via the mailing list reflector. 


To be removed from future notices and invites, please respond with request to remove.


Links of interest


Advanced Cooling – Facilities (ACF)

 OpenComputeProject Tech Week 9-13 Nov (ACF workshop will be 12 Nov)


 Weekly Calls Tuesdays, 1100 ET

ACF Mailing Group:

Topical map of discussions completed and planned

Case 1 – Attaching ACS to existing loop

-          Planning for Pipe Connections –

o   Size, Flow, KW

o   Pipe Path

§  Prefab vs jobsite craftwork

§  Loop to ITE connection

-          CDU/HX Vs Direct Connection

o   No HX

o   FWS/CWS connection via CDU or HX

o   CDU integrated with ITE solutions

-          Risk Considerations

o   Myth Vs Real Risk


§  MTBF/Warranty

o   Condensation risk 

§  Operation above dewpoint

§  Condensation protection/Detection/Collection

o   Leak Risk

§  Design Reliability – apply lessons from decades of success

§  Maintenance consideration

-          Reliability Considerations

o   Concurrent Maintainability

Case 1A – Attaching to existing return loop

-          Similar issues to connection to existing loop

o   additional pump required to set dP from return leg

-          Potential energy savings, maximizing plant dT

-          Minimal issues with dewpoint

Case 2 – Elevated temperature Loop

-          Liquid Cooling solution [mostly] independent from existing cooling solution

-          Provisions to add pipe, pump and HX

o   Above dewpoint = no condensation issues

o   Ambient heat from elevated temp liquids may add load to existing cooling solution

-          Global access to “free” cooling – no chiller plant required

-          Increased opportunity for Heat Reuse applications








Don Mitchell

Data Center Division Manager, Victaulic