Liquid cooling

Technical guideFree to read

Vertiv · 2026

Transforming Colocation Facilities to Meet Demand for AI Compute

Give the rack/pod model a liquid fraction (default about 70% for direct-to-chip) so residual air load is computed automatically.

• Average multi-node AI pod density is projected to rise from 40-100 kW to 100-250 kW.

Liquid coolingElectricalUPS

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IEEE · 2025

Two-Phase Cooling System Performance Under Different Operating Scenarios (ITherm 2025)

Record the refrigerant (with pressure class and GWP) on two-phase CDU objects.

• Refrigerants compared include R1234ze(E), R1234ze(Z), R1233zd(E) and R1336mzz(Z).

Liquid coolingEnergyWater

Technical guideFree to read

Open Compute Project Foundation · 2025

Unraveling the Efficiency, Performance and Sustainability Trade-Offs: Case Study of Liquid Assisted Air Cooling vs Traditional Air Cooling (OCP EMEA Summit 2025)

Distinguish LAAC (no facility water, heat still rejected to room air) from DLC with facility water in the server catalog, and do not reduce air-side cooling load for LAAC racks.

• CPU, NIC and DC-SCM were cooler; DIMMs ran 3-6 C hotter and SSD/PSU temperatures rose.

Liquid coolingCoolingEnergy

Research paperFree to read

Nature (Springer Science and Business Media LLC) · 2025

Using life cycle assessment to drive innovation for sustainable cool clouds

Add a cooling-technology comparison calculator that computes annual energy as IT MW x load factor x PUE x 8760 and applies the paper's Table 3 deltas (PUE -3%/-6%, IT capacity +3%/+6%) and Table 4 savings ranges as tagged defaults.

• Switching to 100% renewable electricity cut GHG by 85-90%, energy demand by 6-7% and blue water by 55-85%; server embodied carbon became more significant.

Liquid coolingSustainabilityWater

Technical guideFree to read

KPMG Türkiye · 2025

Disrupting data-centre design: liquid cooling in the AI era (Veri Merkezi Tasarımında Ezber Bozan Yaklaşım – Yapay Zeka Çağında Soğutma Stratejisi: Sıvı Soğutma ile Dönüşen Veri Merkezleri)

For racks above about 70 kW, warn that air cooling is insufficient and require a liquid-cooling path.

• CRAH fan systems can shrink about 30%, but piping and valves become more complex.

Liquid coolingRacksCooling

Technical guideFree to read

Türk Tesisat Mühendisleri Derneği (TTMD) - TTMD Dergisi · 2021

Liquid cooling trends in data centres (Turkish translation in the TTMD journal)

Offer a W-class selector for liquid-cooled systems that sets supply-temperature ranges and links to whether chillers, dry coolers or towers are needed.

• ASHRAE defines liquid-cooling classes W1 to W5 for facility water temperature, each with a typical infrastructure scheme.

Liquid coolingCoolingEnergy

Technical guideFree to read

Open Compute Project Foundation · 2022

Warm Liquid Cooled Cloud Facilities: What Do We Achieve? (Microsoft submission to OCP)

Default liquid-cooled designs to warm facility water (W40/W45) in chiller-free or dry-cooler-only plant options, citing this paper as supporting evidence.

• The volumetric heat transfer ratio of water to air is cited as about 1900:1.

Liquid coolingCoolingSustainability

White paperFree to read

Huawei Digital Power · 2023

White Paper on the Top 10 Trends of Data Center Facilities

Show WUE alongside PUE in the metrics panel, with region-specific targets as policy presets.

• At 16 kW per rack, power-room area roughly equals IT space (1:1).

SustainabilityEnergyPerformance metrics

White paperCitation

The Green Grid · 2016

WP#70 - Liquid Cooling Technology Update

In the liquid cooling module, use consistent boundary terms (FWS/TCS loops, CDU).

• Related document: ASHRAE TC 9.9 Liquid Cooling Guidelines.

Liquid coolingCooling

White paperCitation

The Green Grid · 2017

WP#73 - Fluid Connector Best Practices for Liquid-Cooled Data Centers

Add catalog fields for quick disconnects: Cv or pressure drop at flow, drip volume per disconnect and filtration (micron) requirement.

• The paper is dated 11 May 2017, edited by David Vranish (CPC), Chris Chapman and Tahir Cader (HPE).

Liquid coolingOperations

White paperCitation

The Green Grid · 2018

WP#78 - An Introduction to Coolant Distribution Units

In the CDU catalog, hold capacity (kW) at approach temperature, flow, pump head and redundancy.

• Dated 17 December 2018; editor Jason Zeiler (CoolIT); download restricted to members.

Liquid coolingCooling

White paperFree to read

Schneider Electric · 2025

10 Data Center Sustainability Improvements Quantified by Environmental Impact

In the sustainability panel compute operational CO2e = IT MWh x PUE x grid EF, with a grid-EF catalog by country/region (default US 454 kg CO2e/MWh incl. upstream) and a renewable-PPA toggle.

• Total GHG falls from 84,100 to 11,300 t CO2e (-87%).

SustainabilityEnergyWater

White paperFree to read

Schneider Electric · 2025

10 Ways to Harness the Energy and Water Efficiencies of Direct Liquid Cooling

Default TCS supply to 40 C for liquid-cooled designs; warn below 30 C (efficiency loss) and above 45 C (server spec limit).

• Evaporative heat rejection uses about 43 L/min per 1 MW of cooling capacity.

Liquid coolingEnergyWater

Technical guideFree to read

Open Compute Project · 2026

Base Specification for Single Phase Water-Based Cold Plate Coolants v1.3

In the commissioning and operations module, generate a TCS fluid-quality test plan with these acceptance limits (conductivity, pH, turbidity, total viable count) at fill and at periodic intervals (default quarterly).

• Turbidity below 5 NTU.

Liquid coolingOperations

White paperFree to read

Schneider Electric · 2019

Capital Cost Analysis of Immersive Liquid-Cooled vs. Air-Cooled Large Data Centers

Use as a seed for the TCO/capex comparison engine: liquidTechPremiumUsdPerW = 0.77 and chillerCrahSavingsUsdPerW = 0.91 (immersion).

• Compaction to 20 kW per rack saves about 10% capex; to 40 kW per rack about 14%.

Liquid coolingCoolingEnergy

Technical guidePDF

Open Compute Project Foundation · 2023

Cold Plate Cooling Loop Requirements, Rev 2

Require each vendor to fill in the parameters of importance tables for cold plates, hoses, quick disconnects, loops, manifolds and CDUs so offers can be compared.

• Glycol at 25% or above prevents bacterial growth; dielectric fluids are insulating but cost more and have higher GWP.

Liquid coolingCoolingRacks

Read / Download

White paperFree to read

Schneider Electric · 2023

Comparison of Dielectric Fluids for Immersive Liquid Cooling of IT Equipment

Add a dielectric-fluid catalog with family (hydrocarbon, fluorocarbon), phase (1p, 2p), flash point, boiling point, GWP, PFAS status, cost per litre and annual loss percentage.

• Sealed two-phase systems can lose about 1 to 2% of fluid (evaporation) per year.

Liquid coolingFire safetySustainability

Technical guideFree to read

Open Compute Project · 2024

Data Center Liquid Distribution Guidance & Reference Designs, Rev 1.0 (OCP Advanced Cooling Facilities)

In the liquid-cooling calculator implement Q = m*cp*delta-T for TCS/FWS sizing (water cp 4.18 kJ/kg-K, PG25 option) and size pipes by maximum velocity.

• Q = volumetric flow x delta-T x density x specific heat; by volume water carries about 3,300 times the heat of air.

Liquid coolingCoolingWater

Technical guidePDF

Open Compute Project Foundation · 2024

Data Center Liquid Distribution Guidance & Reference Designs, Revision 1.0 (January 8, 2024)

Reserve space for tap-off valves, pipe paths with straight runs, valve and fitting replacement, drainage and condensation collection in the original design.

• Liquid above 50 °C (122 °F) is far better for heat reuse than 35 °C (95 °F) air, and improves ERE.

Liquid coolingCoolingReliability

Read / Download

Technical guideFree to read

Vertiv · 2023

Deploying Liquid Cooling in the Data Center: A Guide to High-Density Cooling (1 MW IT load)

Calculation default: DLC flow = 1.5 L/min per kW of liquid-captured heat; to adjust by dT use flow = P/(4.18 x dT) L/s.

• Newest AI servers approach 6-10 kW TDP per server

Liquid coolingCoolingRacks

White paperFree to read

Schneider Electric · 2025

Direct Liquid Cooling System Challenges in Data Centers

Use the eight challenges as a DLC readiness checklist in the commissioning and design-review module.

• Heat capture ratio defines the air share: 80% liquid capture leaves 20% for air cooling.

Liquid coolingCoolingOperations

StandardFree to read

ASHRAE TC 9.9 · 2021

Emergence and Expansion of Liquid Cooling in Mainstream Data Centers

Add class H1 and the W17/W27/W32/W40/W45/W+ facility-water classes to the thermal catalog as enumerations.

• Context: A1 allowable max 32 degC, A4 max 45 degC.

Liquid coolingCoolingAirflow

Technical guideCitation

NREL · 2019

Energy Performance Evaluation of Aquila's Aquarius Fixed Cold Plate Cooling System at NREL's High Performance Computing Center (NREL/TP-2C00-73356, February 2019)

Use the measured capture fractions (98.3%, 93.4%, 86.1%) to estimate the residual air load for a fixed cold plate rack, remembering that power shelves, CDUs and switches stayed air-cooled.

• The rack CDU draws about 750-800 W.

Liquid coolingCoolingRacks

White paperFree to read

Schneider Electric · 2019

Five Reasons to Adopt Liquid Cooling

Use 20 kW per rack (the Green Grid midpoint) as the default threshold at which the wizard recommends evaluating liquid cooling.

• Liquid cooling supports racks of 100 kW and more.

Liquid coolingEnergyWater

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