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

Overview

The loop is filled once during construction and circulates between servers and chillers, with no fresh-water make-up for cooling. Chip-level cooling permits warmer coolant temperatures, so high-efficiency economizing chillers offset the energy penalty of dropping evaporation. The design is said to avoid more than 125 million litres of water per datacenter per year, a figure based on the FY24 withdrawal WUE of 0.30 L/kWh.

Fleet WUE was 0.30 L/kWh in FY24, a 39% improvement from 0.49 L/kWh in 2021 and about 80% better than first-generation datacenters. Replacing evaporative systems with mechanical cooling raises PUE; the post describes the net effect as a nominal increase in annual energy and gives no numeric PUE value. The timeline is explicit: all new designs use this approach from August 2024, pilots in Phoenix and Mt. Pleasant were planned for 2026, and the first sites come online from late 2027.

The post is a corporate announcement; it carries no engineering detail such as pipe sizes, CDU sizing or water temperatures, and it does not quantify the energy cost. The 125 million litres is therefore an estimate derived from the FY24 WUE, not a measured result. Warmer coolant increases the hours in which economizing chillers can run without mechanical cooling; the size of that gain is not given in the post.

Key points

1. The design avoids more than 125 million litres of water per year per datacenter (based on FY24 withdrawal WUE of 0.30 L/kWh).
2. Fleet WUE 0.30 L/kWh in FY24, a 39% improvement from 0.49 L/kWh in 2021; about 80% better than first-generation sites.
3. Replacing evaporative systems with mechanical cooling raises PUE; net effect is a nominal increase in annual energy.
4. Closed loop filled during construction, no fresh-water make-up for cooling.
5. All new designs from August 2024; first sites online late 2027.
6. Pilots in Phoenix and Mt. Pleasant were planned for 2026.

Using it in design

• Add 'closed-loop DLC + dry cooler / air-cooled economizing chiller (zero-evaporation)' to the cooling-option catalog with WUE_cooling about 0.
• Define a PUE penalty parameter versus evaporative cooling (default +0.02-0.05, user-editable; this value does not come from the source).
• Raise facility water temperature (e.g. W32-W45) to increase economizer hours and show water saved per MW-year.

Who should read it

Mechanical designers and sustainability managers weighing the energy and water balance of giving up evaporative cooling.

Related standards

• ASHRAE TC9.9 Liquid Cooling Guidelines
• ISO/IEC 30134-9

Publication details

Authors

Steve Solomon

Publisher

Microsoft

Year

2024

Document language

English

Source type

Expert / community

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation