Water

Energy Efficient HPC Working Group / U.S. DOE FEMP · 2018

The Facility Perspective on Liquid Cooling: Experiences and Proposed Open Specification (SC18 Birds of a Feather)

Give liquid-cooling components in the catalogue wetted-material lists, and flag aluminium or zinc on a loop with copper cold plates.

• Maximum particulate size 50 microns, optionally with bypass filtration.

arXiv preprint · 2026

The fallacy of sustainable Generative AI: limitations in EU environmental regulation of data centres and paths forward

For EU projects, add an EED compliance module that flags facilities of 500 kW and above as reportable.

• The second EU technical report suggests targets of PUE 1.3 for new data centres and WUE below 0.4 m3/MWh.

Schneider Electric · 2012

The Top 9 Mistakes in Data Center Planning

Require design criteria (tier, density, capacity) to be derived from stated business goals before site and space tools are used.

• IDC puts the average data centre at 9 years old; Gartner calls any site over 7 years obsolete.

Resources, Conservation and Recycling (Elsevier) · 2025

The water use of data center workloads: A review and assessment of key determinants

In the water module, report both on-site WUE and grid (source) water using regional factors.

• Workload-level water use varies by more than 10,000-fold.

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).

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.

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.

Uptime Institute Journal · 2025

Water is local: generalities do not apply (Jay Dietrich)

Model annual water use from heat rejection type, set points and hourly climate rather than a fixed WUE.

• Context: a typical US household uses about 110,000 US gal (420 m3) per year.

Consulting-Specifying Engineer · 2023

What do you need to know about designing HVAC systems in data centers? (roundtable)

Flag hot-climate risks in site design checks: ambient above 115 F, and recirculation between chillers and generator exhaust; suggest CFD.

• Unusual heat sinks: snow storage, canal water, in-rack CO2.

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).

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%).

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.

Lawrence Berkeley National Laboratory · 2024

2024 United States Data Center Energy Usage Report (LBNL-2001637, December 2024)

Take AI rack and node power assumptions (3.4 to 12.2 kW per 8-GPU server, 20% idle) as a cross-check on IT load models, not as a substitute for vendor data.

• U.S. data centers used about 76 TWh (1.9% of U.S. electricity) in 2018 and 176 TWh (4.4%) in 2023.

U.S. Department of Energy / FEMP · Year not stated

Best Management Practice #10: Cooling Tower Management

Keep evaporation, drift, leaks and blowdown as separate items in the model.

BRE Global · 2019

BREEAM International New Construction 2016 — Data Centre Annex (Pilot), Annex 1 and Annex 2

Metering rule: if projected PUE is below 1.2 require IT-level (PUE3) metering; at 1.2-1.5 require at least PDU-output (PUE2); otherwise UPS-output (PUE1) is acceptable.

• Launched as a pilot in November 2019; replaces BREEAM Data Centres 2010.

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.

Digital Realty · 2025

Digital Realty: Sustainability (portfolio PUE and renewable coverage)

Use portfolio PUE of about 1.38-1.4 as the benchmark for multi-tenant colocation (against hyperscale about 1.1 and industry about 1.54).

• Portfolio PUE 1.38.

Schneider Electric · 2011

Economizer Modes of Data Center Cooling Systems

Compute economizer hours from hourly climate data (dry bulb and wet bulb) against the chosen supply setpoint and approach temperatures, and report partial and full economizer hours separately.

• Cooling towers consume about 40 gpm per 1,000 tons of capacity (151.4 L/min).

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.

Google · 2026

Google Data Centers — Operating sustainably (energy and water)

In the cooling-selection UX present an explicit energy-versus-water trade-off (PUE versus WUE) per site, with a water-stress input (for example a WRI Aqueduct category).

• 87% of 2025 freshwater withdrawal from sources at low or medium depletion/scarcity risk.