WP#68 - The Performance Indicator: Assessing and Visualizing Data Center Cooling Performance

Overview

The document is dated 22 June 2016; its editors include Mark Seymour (Future Facilities). The Performance Indicator brings together three cooling performance metrics: one uses PUE, and the other two are IT thermal conformance and IT thermal resilience.

The paper shows trade-offs between thermal performance and energy savings. It includes calculation methods and a detailed case study, and its authors recommend modelling, simulation and monitoring. The trio stresses that cooling performance should be judged not only by measured energy but also by the actual temperature conditions of the equipment.

The most important warning is that focusing on PUE alone can cause stranded capacity or unintended risk. A low-PUE target may push IT inlet temperatures outside the recommended range, or leave redundancy inadequate when a cooling failure occurs.

As a limit, the summary gives neither formulas nor thresholds for the metrics; the document itself should be consulted. The related source is ASHRAE Thermal Guidelines, from which the notions of recommended and allowable ranges derive.

Key points

1. Dated 22 June 2016; editors include Mark Seymour (Future Facilities).
2. Three cooling performance metrics, one using PUE.
3. Defines IT thermal conformance and IT thermal resilience.
4. Includes calculation methods and a detailed case study.
5. Warns that focusing on PUE alone can cause stranded capacity or unintended risk.
6. Recommends modelling, simulation and monitoring.
7. Related source: ASHRAE Thermal Guidelines.

Using it in design

• In airflow/CFD results, report thermal conformance (share of IT inlets within the recommended range) alongside PUE.
• Also report thermal resilience (share of IT inlets within the allowable range after a cooling failure).
• Do not make the PUE target the sole optimisation criterion; weigh stranded capacity and risk together.

Who should read it

Engineers designing cooling and airflow, CFD analysts, and operations teams.

Related standards

• ASHRAE Thermal Guidelines

Publication details

Authors

Mark Seymour; Maira Bana; David Wang; Danny Cummins; Veerendra Para; Magnus Herrlin; James Betts; Jay Vincent; Henry Wong; Chang Tsann; Bob Landstrom

Publisher

The Green Grid

Year

2016

Document number

WP 68

Document language

English

Source type

Industry body

Access

Citation only

Licence

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

Citation