How to design data centers: HVAC systems (roundtable)

Overview

In this 2021 roundtable from Consulting-Specifying Engineer, mission-critical engineers share results from data centre HVAC projects. The first example is a multistory retrofit that reached an annualized PUE of 1.15 using air-cooled chillers with integrated free cooling. The project allowed rack intake up to the A2 limit of 95 F, and the air-cooled chillers gave 100% capacity without compressors at 40 F ambient.

The second example is the 16-year-old Massachusetts Information Technology Center, an existing government data centre where transducers, surveys and modelling cut energy use by 24% and water use by 37%. The third is NREL's ESIF, where water-cooled racks with thermosyphon coolers plus towers achieved PUE 1.04 and halved water use. At the University of Utah, the outside-air economizer is limited by a weather station during high humidity or poor air quality, and PUE stays below 1.3.

Respondents also cover leak protection for piping near IT or electrical equipment and chilled-water return-first strategies to widen delta-T. Piping near IT or electrical equipment needs drip trays with leak detection and spray guards at joints. The piece is a freely accessible expert article, not a standard or calculation method; only the record's summary and key facts were used here and the full text was not read.

Key points

1. Retrofit allowed rack intake up to the A2 limit of 95 F; air-cooled chillers gave 100% capacity without compressors at 40 F ambient; annualized PUE 1.15.
2. Massachusetts Information Technology Center (16 years old): 24% energy and 37% water reduction via transducers, surveys and modelling.
3. NREL ESIF: water-cooled racks with thermosyphon plus towers achieved PUE 1.04 and halved water use.
4. University of Utah: outside-air economizer limited by a weather station during high humidity or poor air quality; PUE below 1.3.
5. Piping near IT or electrical equipment needs drip trays with leak detection and spray guards at joints.

Using it in design

• Offer integrated-free-cooling chillers as a catalogue option with the free-cooling changeover ambient field.
• Apply a rule requiring drip trays with leak detection when chilled-water or liquid-cooling piping routes over IT or electrical equipment.
• In existing facilities, treat surveys and right-sizing as the first step for energy and water savings.
• Design the outside-air economizer with limiting logic tied to humidity and air quality.

Who should read it

Mechanical engineers designing, retrofitting or operating data centre HVAC systems.

Related standards

• ASHRAE Thermal Guidelines for Data Processing Environments

Publication details

Authors

Peter Czerwinski; Garr Di Salvo; Brian Rener; Scott Gatewood

Publisher

Consulting-Specifying Engineer

Year

2021

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