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StandardCitation2021

Information technology - Data centres key performance indicators - Part 6: Energy Reuse Factor (ERF)

ISO/IEC · ISO/IEC JTC 1

The standard defining ERF, the KPI for how much of a data centre's consumed energy is reused outside it, typically as waste heat.

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Overview

ISO/IEC 30134-6:2021 is the sixth part of the data centre key performance indicator (KPI) series and defines the Energy Reuse Factor (ERF). ERF quantifies how much of the energy consumed in a data centre is reused outside it, typically as waste heat. The standard was published as edition 1 on 11 August 2021 and runs to 14 pages. This page rests on the publisher's public catalogue abstract and product metadata.

The calculation is simple: ERF is the reused energy divided by the sum of all energy consumed in the data centre. Unlike PUE, the indicator does not express efficiency inside the facility boundary but the extent to which the facility's energy finds value outside it. It is therefore a complementary indicator in projects where waste heat goes to district heating or a similar off-taker.

The standard has a clear limit: the reuse process itself is not part of the data centre, and ERF does not reflect its efficiency. How heat is used on the receiving side, or how much electricity a heat pump consumes, falls outside ERF's scope. The indicator counts only the energy that leaves the boundary.

Related documents include ISO/IEC 30134-1, EN 50600-4-6 and EU Energy Efficiency Directive 2023/1791. This framework shows that ERF is gaining importance in reporting and regulatory contexts.

Key points

  1. ERF is the reused energy divided by the sum of all energy consumed in the data centre.
  2. The indicator quantifies reuse of energy consumed in a data centre.
  3. The reuse process is not part of the data centre and ERF does not reflect its efficiency.
  4. Edition 1, published 2021-08-11, 14 pages.
  5. Related documents: ISO/IEC 30134-1, EN 50600-4-6, EU Energy Efficiency Directive 2023/1791.
  6. The standard is paid; the full text is not redistributed.

Using it in design

  • In a heat-reuse calculator, compute ERF as exported heat, metered at the boundary heat exchanger, divided by total facility energy, on a range of 0 to 1.
  • In district-heating scenarios, do not net the off-taker's heat-pump electricity into ERF; show it as a separate line.
  • Plan the heat metering point at the boundary heat exchanger, including meter class, at design stage.

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Who should read it

Data centre designers and energy engineers planning waste-heat recovery and sustainability reporting.

Related standards

  • ISO/IEC 30134-1
  • EN 50600-4-6
  • EU Energy Efficiency Directive 2023/1791

Publication details

Authors
ISO/IEC JTC 1
Publisher
ISO/IEC
Year
2021
Document number
ISO/IEC 30134-6:2021
Document language
English
Source type
Standard
Access
Citation only
Licence
Copyright retained; citation only — the publisher’s terms apply to the original document
Original licence note

Paid standard. Record built only from the publisher's public catalogue abstract and product metadata; full text not redistributed.

Citation

ISO/IEC JTC 1 (2021). Information technology - Data centres key performance indicators - Part 6: Energy Reuse Factor (ERF). ISO/IEC. ISO/IEC 30134-6:2021. https://webstore.iec.ch/en/publication/70719

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