Water

Schneider Electric · 2017

High Efficiency Indirect Air Economizer-based Cooling for Data Centers

Add the indirect evaporative cooler (IEC) as a plant type, with parameters for approach temperature, wet-bulb effectiveness, trim DX capacity fraction and water use only during evaporative hours.

• With evaporative assist: 4,394 h (50%) at 21.1 C; 6,289 h (72%) at 27 C.

Schneider Electric · 2021

How Higher Chilled Water Temperature Can Improve Data Center Cooling System Efficiency

Expose CHW supply temperature (default 15 C for new builds, range 7 to 21 C) and CHW deltaT as design inputs, and recompute economizer hours, chiller kW and CRAH coil selection when they change.

• The traditional CHW supply setpoint is 7 C (45 F).

Lawrence Berkeley National Laboratory · 2017

Humidity Control in Data Centers (March 8, 2017)

Write the humidity strategy around room dew point: set a wide dead band (about 16 °F to 59 °F dew point unless the IT owner agrees a higher lower limit) rather than a narrow RH band.

• Class A1 equipment is known to function up to 90 °F and A4 up to 113 °F, although all classes share the same recommended range.

U.S. Green Building Council · 2019

LEED v4.1 Building Design and Construction (incl. BD+C: Data Centers)

Build a "LEED Data Centers" checklist in the sustainability module that requires an annualised design PUE from the app's energy model.

• Colocation data centres may use Core & Shell thresholds in some v4.1 credits.

NREL · 2018

DCDM1: Lessons Learned from the World's Most Energy Efficient Data Center (NREL/PR-2C00-70433, March 12, 2018)

Fix two design temperatures early, the coolest supply you can produce on the hottest day and the return temperature needed for heat reuse, and select IT equipment against them.

• Ten 100-kW racks take much less space than the equivalent fifty 20-kW air-cooled racks.

Microsoft · 2025

Measuring energy and water efficiency for Microsoft datacenters

Expose climate-driven partial PUE/WUE in site comparison; flag that hot-humid regions (e.g. APAC tropics) give about 0.1 higher PUE for the same design.

• Global PUE 1.16 (FY24) and 1.17 (FY25); WUE 0.30 (FY24) and 0.27 L/kWh (FY25).

Meta · 2025

Meta 2025 Environmental Data Index (data center PUE and WUE)

Take hyperscale best-in-class WUE of about 0.2 L/kWh (withdrawal basis) and PUE of about 1.08 as benchmarks.

• Total water withdrawal 3,726 ML (2020) -> 5,637 ML (2024).

Microsoft · 2024

Sustainable by design: Next-generation datacenters consume zero water for cooling

Add 'closed-loop DLC + dry cooler / air-cooled economizing chiller (zero-evaporation)' to the cooling-option catalog with WUE_cooling about 0.

• Pilots in Phoenix and Mt. Pleasant were planned for 2026.

NREL · 2017

Thermosyphon Cooler Hybrid System for Water Savings in an Energy-Efficient HPC Data Center: Modeling and Installation (NREL/CP-2C00-66690, February 2017)

Place a dry stage upstream of the tower and size it against the share of hours where warm return water exceeds dry-bulb temperature by enough margin, as the 9.4 °C transition point does here.

• Building heat reuse peaks at 0.434 MW of a 0.910 MW load, leaving 0.496 MW to reject to atmosphere.

NREL · 2018

Thermosyphon Cooler Hybrid System for Water Savings in an Energy-Efficient HPC Data Center: Results (NREL/TP-2C00-72196, September 2018)

Check whether the warm return water from liquid cooling (here 84 °F after energy recovery) leaves enough temperature difference to ambient for a dry or hybrid stage, and size it against local dry-bulb hours.

• First-year heat rejection: 10.5% building heat reuse, 42.5% thermosyphon and 47% cooling towers.

Lawrence Berkeley National Laboratory · 2016

United States Data Center Energy Usage Report (LBNL-1005775, June 2016)

Use the space-type PUE table as a sanity check on early-stage PUE assumptions, remembering these are 2014 national averages, not design targets.

• Electricity use grew about 4% over 2010-2014, versus about 24% over 2005-2010 and nearly 90% over 2000-2005.

Uptime Institute · 2026

Uptime Institute Global Data Center Survey 2026 (16th annual) — press release

Make 30 kW/rack the threshold where the app moves from 'enhanced air' guidance to 'liquid-ready' guidance (rear-door heat exchanger / direct liquid cooling)

• 52% of respondents in North America and Europe; 800+ responses

Schneider Electric · 2026

Water Usage at AI Scale: Insights from a 100 MW Comparative Analysis

Compute and display WUE (L/kWh IT) next to PUE for every cooling design.

• Dallas WUE falls from 0.42 to 0.22 L/kWh; Paris from 0.12 to 0.06 L/kWh.

ASHRAE TC 9.9 · 2019

Water-Cooled Servers: Common Designs, Components, and Processes

Enforce TCS supplyTemp >= roomDewPoint + 2 degC.

• pH: FWS 7-9; TCS 8.0-9.5.

Schneider Electric · 2023

Why Data Centers Must Prioritize Environmental Sustainability: Four Key Drivers

Keep a jurisdiction rules table, for example Germany with PUE_max 1.2 for new builds and heat_reuse_min rising from 10% to 20%.

• Data centres consume roughly 2% of global electricity.

The Green Grid · 2011

WP#35 - Water Usage Effectiveness (WUE): A Green Grid Data Center Sustainability Metric

In the water module, compute WUE_site = annual make-up + humidification water (L) / IT kWh from the hourly cooling model (evaporation ~ heat rejected, cycles of concentration for blowdown).

The Green Grid · 2025

WP#93 Data Center Resource Effectiveness (DCRE) v1 Metric

Add a water-stress index from a public water-risk atlas to the site catalogue and use it to weight WUE.

• Published 2025 as v1; related standard ISO/IEC 30134-9.

The Green Grid · 2025

WP#95 Water Usage Impact (WUI) v1 Metric

Put a water-stress rating beside WUE on the site-selection screen.

• Published 2025 as v1; related standard ISO/IEC 30134-9.