ISO/IEC TR 21897:2022

TECHNICAL ISO/IEC TR
REPORT 21897
First edition
2022-11
Information technology — Data
centres — Impact of the ISO 52000
series on energy performance of
buildings
Technologies de l'information — Centres de données — Impact de la
série ISO 52000 sur la performance énergétique des bâtiments
Reference number
ISO/IEC TR 21897:2022(E)
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ISO/IEC TR 21897:2022(E)
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ISO/IEC TR 21897:2022(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Abbreviated terms . 4
3.3 Symbols (variables) . 4
3.4 Symbols (indices) . 5
4 Background, motivation and exclusions . 6
4.1 Background and motivation . 6
4.2 Exclusions . 7
5 Data centre assessment boundary . 7
5.1 Data centre boundary in the ISO/IEC 30134 series . 7
5.2 Assessment boundary of the system in the ISO 52000 series . 8
6 General principles of the overarching EPB framework and procedures .9
6.1 Output of the method . . 9
6.2 General description of the procedures. 10
6.3 General description of the routing . 10
6.4 Types of assessment . 11
6.4.1 General . 11
6.4.2 Calculated energy performance . 11
6.4.3 Measured overall energy performance and comparison with calculations.12
7 Assessment of primary or weighted energy performance .13
7.1 Weighted overall energy balance . 13
7.2 Primary energy factors .13
7.3 Weighting factors for exported energy . 15
8 General approach for data centre energy flows .15
8.1 Data centre energy flows considered in the ISO/IEC 30134 series .15
8.2 General energy flows considered in the ISO 52000 series . 15
8.2.1 General .15
8.2.2 Electricity and other carriers with exportation . 16
8.2.3 Energy carriers without exportation . 20
8.2.4 Exported heat on-site produced and not included in thermal use of the
system . 20
8.3 Data centre energy flows in an EPB approach . 21
9 Impacts of the EPB approach on data centre KPIs .22
9.1 Impacts on conversion factors (case of metered energy consumption) .22
9.2 Impact on power usage effectiveness (PUE — ISO/IEC 30134-2) . 25
9.3 Impact on the renewable energy factor (REF — ISO/IEC 30134-3) . 25
9.4 Impact on the energy reuse factor (ERF — ISO/IEC 30134-6) . 26
9.5 Impact on the excess electrical energy factor (XEEF — ISO/IEC TR 23050) .26
9.6 Impact on IT equipment energy efficiency for servers (ITEE — ISO/IEC 30134-4) .26
SV
Annex A (informative) Examples of primary energy assessment of a data centre as used for
PUE assessment .27
Annex B (informative) Examples of primary energy assessment of data centre as used for
REF assessment .35
Annex C (informative) Examples of primary energy assessment of data centre as used for
ERF assessment .42
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ISO/IEC TR 21897:2022(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria
needed for the different types of document should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC
list of patent declarations received (see https://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 39, Sustainability, IT and data centres.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
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ISO/IEC TR 21897:2022(E)
Introduction
It is recognized that no “free” energy exists, even if certain processes or technical solutions are
implemented in data centres, whose names can potentially suggest that energy is free (e.g. renewable
energy, "free" cooling with air or water, geo-cooling, etc.).
In particular:
— even if the cost of certain renewable energy sources is low compared to non-renewable sources,
there are still costs associated with the use or implementation of renewable energies such as
transport and/or storage;
— some energy-efficient solutions implemented in data centres can also have other capital and
operational energy costs;
— the remaining energy going out of a subsystem of a data centre, if not evaluated inside or outside
the data centre boundary, is lost; every effort in order to minimize these losses results in improved
energy efficiency of the data centre.
Regulatory frameworks exist (for example, in the European Union) which request primary energy
assessment and that the energy consumption of computer rooms included in commercial or residential
buildings can be assessed within primary energy as part of the overall energy consumption for these
types of buildings.
The common objective of the key performance indicators (KPI) specified in the ISO/IEC 30134 series is
the efficient or effective use or utilization of energy and other resources.
The ISO 52000 series defines methods and tools to assess the energy performance of buildings (EPB),
routing and energy balance, together with greenhouse gas emissions.
These methods and tools are to be used (when mandatory) for mixed use buildings that include a data
centre or server room in their premises. They can also be used in the case of stand-alone data centres.
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TECHNICAL REPORT ISO/IEC TR 21897:2022(E)
Information technology — Data centres — Impact of the
ISO 52000 series on energy performance of buildings
1 Scope
This document proposes elements for the expression of energy production, storage, reuse and
consumption in reference to primary energy in data centres, taking into account both the elements
needed for energy assessment and the concepts developed in the framework of the ISO 52000 series for
energy performance of buildings (EPB).
This document:
— provides the main definitions and concepts from the ISO 52000 series needed to make a primary
energy assessment for data centres;
— provides approaches for discriminating true sources of energy used by a given data centre;
— compares, where relevant, the terms used in both the ISO/IEC 30134 series and ISO 52000 series
and provides explanations on the use of factors for converting final or delivered energy to primary
energy which take a different approach in each series (and how to move from one to the other);
— illustrates the impact of using the EPB approach on data-centre-energy-related key performance
indicators (KPIs), both in general and by the provision of examples;
— provides known sources of weighting or conversion factors to be used when there are no recognized
or agreed local factors applicable to the studied data centre energy performance assessment.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 30134 (all parts), Information technology — Data centres key performance indicators
ISO/IEC 22237 (all parts), Information technology — Data centre facilities and infrastructures
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in the ISO/IEC 30134 series and the
ISO/IEC 22237 series and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1.1
assessment boundary
boundary where the delivered and exported energy are measured or calculated
[SOURCE: ISO 52000-1:2017, 3.4.2]
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ISO/IEC TR 21897:2022(E)
3.1.2
bin
statistical temperature class (sometimes a class interval) for the outdoor air temperature, with the
class limits expressed in a temperature unitNote 1 to entry: The bin usually includes non-consecutive
interval of times with the same temperature condition.
[SOURCE: ISO 52000-1:2017, 3.6.2]
3.1.3
delivered energy
energy, expressed per energy carrier, supplied to the data centre through the assessment boundary, to
satisfy the uses taken into account or to produce the exported energy
Note 1 to entry: Delivered energy can be calculated for defined energy uses or it can be measured.
[SOURCE: ISO 52000-1:2017, 3.4.6, modified — Reference to "technical building systems" replaced by
"data centre".]
3.1.4
distant
not on-site nor nearby
[SOURCE: ISO 52000-1:2017, 3.4.7, modified — Domain changed from "" to " data centre premises>".]
3.1.5
electricity grid
public electricity network
[SOURCE: ISO 52000-1:2017, 3.4.8]
3.1.6
energy carrier
substance or phenomenon that can be used to produce mechanical work or heat or to operate chemical
or physical processes
[SOURCE: ISO 52000-1:2017, 3.4.9]
3.1.7
energy source
source from which useful energy can be extracted or recovered either directly or by means of a
conversion or transformation process
EXAMPLE Oil or gas fields, coal mines, sun, wind, the ground (geothermal energy), the ocean (wave energy,
ocean thermal energy), forests etc.
[SOURCE: ISO 52000-1:2017, 3.4.15]
3.1.8
exported energy
energy, expressed per energy carrier, supplied by the technical data centre systems through the
assessment boundary
Note 1 to entry: It can be specified by generation types [e.g. combined heat and power (CHP) and photovoltaic
(PV)] in order to apply different conversion factors.
Note 2 to entry: Exported energy can be calculated or it can be measured.
[SOURCE: ISO 52000-1:2017, 3.4.20, modified — Reference to "building systems" replaced by "data
centre systems"; in Note 1 to entry, reference to "weighting factors" replaced by "conversion factors".]
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ISO/IEC TR 21897:2022(E)
3.1.9
final energy
energy as delivered to an energy-using system
Note 1 to entry: This concept is sometimes referred to as "delivered energy".
[SOURCE: ISO/IEC 13273-1:2015, 3.1.11, modified — Note 2 to entry deleted.]
3.1.10
nearby
usable only at local or district level, connected to the same branch of the distribution
network (for electricity: distribution network meaning medium voltage or lower) or having a dedicated
connection, requiring specific equipment for the assessed data centre to be connected to it (e.g. district
heating or cooling)
Note 1 to entry: This definition is based on that given for the same term in ISO 52000-1:2017, 3.4.24.
Note 2 to entry: The concept of "nearby" is expressed here in relation to the data centre premises. See Annex A
and Annex B for further explanation.
3.1.11
non-renewable energy
energy taken from a source which is depleted by extraction (e.g. fossil fuels)
Note 1 to entry: Resource that exists in a finite amount that cannot be replenished on a human time scale.
[SOURCE: ISO 52000-1:2017, 3.4.26]
3.1.12
on-site
building, premises and the parcel of land on which the data centre is located
Note 1 to entry: On-site is defining a strong link between the energy source (localization and interaction) and the
data centre
[SOURCE: ISO 52000-1:2017, 3.4.27, modified — References to "the building" replaced by "the data
centre" in both the definition and Note 1 to entry; "Building" added to the beginning of the definition.]
3.1.13
perimeter
origin of delivered energy
Note 1 to entry: This document distinguishes between "on-site", "nearby" and "distant" energy sources.
[SOURCE: ISO 52000-1:2017, 3.4.28]
3.1.14
primary energy
energy that has not been subjected to any conversion or transformation process
Note 1 to entry: Primary energy includes non-renewable energy and renewable energy. If both are taken into
account it can be called total primary energy.
[SOURCE: ISO 52000-1:2017, 3.4.29]
3.1.15
technical data centre system
technical equipment for heating, cooling, ventilation, humidification, dehumidification, domestic hot
water, lighting, building automation and control and electricity production (other than for IT services)
Note 1 to entry: A technical data centre system can refer to one or to several data centre services.
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ISO/IEC TR 21897:2022(E)
Note 2 to entry: A technical data centre system is composed of different sub-systems. A technical data centre
sub-system is a part of a technical data centre that performs a special function (e.g. air handling, cold generation
and distribution, water-based cooling, etc.).
Note 3 to entry: Electricity production can include electrical power supply generation equipment (including fuel
storage), cogeneration, wind power and photovoltaic systems, transformers.
3.1.16
uninterruptible power system
UPS
combination of convertors, switches and energy storage devices (such as batteries), constituting a
power system for maintaining continuity of load power in case of input power failure
Note 1 to entry: Continuity of load power occurs when voltage and frequency are within rated steady-state and
transient tolerance bands, and with distortion and interruptions within the limits specified for the output port.
Input power failure occurs when voltage and frequency are outside rated steady-state and transient tolerance
bands, or with distortion or interruptions outside the limits specified for the UPS.
[SOURCE: IEC 62040-1:2017, 3.1.01]
3.2 Abbreviated terms
For the purposes of this document, the abbreviated terms given in the ISO/IEC 30134 series, the
ISO/IEC 22237 series and the following apply.
CHP combined heat and power
COP coefficient of performance
EPB energy performance of buildings
ERF energy reuse factor
ITEEsv IT equipment energy efficiency for servers
PV photovoltaic
CHP cogeneration, combined heat and power
PDU power distribution unit
PUE power usage effectiveness
REF renewable energy factor
RER renewable energy ratio
SLA service level agreement
UPS uninterruptible power system
XEEF excess electrical energy factor
3.3 Symbols (variables)
For the purposes of this document, the following symbols apply. These symbols are used throughout
the document in combination with the indices defined in 3.4.
E energy consumption or loss
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ISO/IEC TR 21897:2022(E)
f weighting factor (e.g. primary energy factor)
Q quantity of heat
R ratio
t time
X conversion factor (ratio of weighting factors)
EXAMPLE 1 E = total data centre primary energy
pe;DC;tot
EXAMPLE 2 E = total information technology equipment primary energy
pe;IT;tot
EXAMPLE 3 E = non-renewable energy delivered to the data centre
del;DC;nren
EXAMPLE 4 E = renewable energy produced nearby the data centre
nb;DC;ren
3.4 Symbols (indices)
For the purposes of this document, the following indices apply:
A other appliances
AB assessment boundary
an annually
avl available
C temperature and humidity control systems
chp combined heat and power
cooling delivered (energy) used by the entire cooling system
cr(1), cr(2)., energy carriers
cr(n)
DC data centre
del delivered (energy)
dhc district heating/cooling
dst distant
el electricity
EnEPus;el total energy for non-EPB uses and DC and total energy for non-EPB non-DC uses
EPus energy performance use
excess excess (energy)
exp exported (energy)
gas gas
gen produced by the generator
grid from public electricity grid
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ISO/IEC TR 21897:2022(E)
in total delivered (electrical energy) provided to the data centre
IT information technology equipment
meas measured
nb nearby
nDC non-data-centre
nEPus non-energy-performance use
nexp without energy export
nren non-renewable (energy)
pe primary (energy)
pr produced on-site
PSD power supply and distribution
Q quantity of heat
rdel redelivered (energy)
ren renewable (energy)
reuse energy reuse
S service
tmp temporarily exported (to be reused later) either to the grid or to an energy storage
tot total
we weighted (energy)
Z zone
4 Background, motivation and exclusions
4.1 Background and motivation
The common objective of the key performance indicators (KPIs) of the ISO/IEC 30134 series is the
efficient or effective use or utilization of resources including:
— minimization of energy and other resource consumption;
— effectiveness of the IT load (processing, storage and transport) within the data centre, maximizing
the IT output with the minimum energy consumption;
— reuse of unconsumed resources (e.g. energy reuse in the form of waste heat);
— utilization of renewable energy, both generated on- and off-site.
The KPIs consider the different data centre services (IT, cooling, lighting, power supply, etc.) in relation
to the main form of final energy used in data centres, electricity. Final (or delivered) energy can come
from different sources of primary energy, and to do such assessments it is necessary to consider if
the energy is the result of investment of effort done by the data centre owner/manager or by energy
providers.
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ISO/IEC TR 21897:2022(E)
In general, the ISO/IEC 30134 series provides essential tools for the resource management of data
centres both in terms of operation of facilities and of decision-making. These documents can also be
used to support pre-regulatory or regulatory proceedings, or to benchmark facilities projects or
realizations.
In many countries approaches of incentives for energy efficiency such as energy saving certificates
or certificates of renewable energy production have been implemented. Whether at the level of data
centres management or at incentive or regulatory processes, the existing measures can require the
energy performance to be expressed in a primary energy reference system.
The ISO 52000 series aims at achieving international harmonization of the methodology for the
assessment of the energy performance of buildings (EPB). The documents from the ISO 52000 series
can be used for energy assessment of buildings containing a data centre.
4.2 Exclusions
This document does not address design, material or organizational aspects of data centre power supply
and energy management, but focuses instead on methods, tools and references to process delivered and
exported energy data from various carriers to assess primary energy balances in data centres.
Although the following topics are important and can affect the data centre energy efficiency, they will
not be covered in this document.
— Monitoring or metering of energy consumption (developed in the ISO/IEC 30134 series), due to the
fact that primary energy is calculated from final energy and losses measurement or assessment.
— Power quality relation to energy production, transport and transformation; assessing the primary
energy balance of a data centre can lead to challenging energy carriers and it is the role of data
centre managers to ensure that the choice of an energy carrier resulting from high primary energy
efficiency also meets the power quality criteria such as those for electronic equipment, but these
issues are not treated in this document.
NOTE ISO/IEC 30134-1:2016, Clause A.2 insists on the relationship between absolute energy consumption
(contribution to KPIs) and availability of service [level of service level agreement (SLA)]. It proposes solutions
based on uninterruptable power systems (UPS), stressing that tolerance to faults and ensuring availability to
meet SLAs are important factors in the energy consumption of data centre equipment and infrastructures. In
terms of energy assessment, the higher the power quality, the greater the potential losses in the data centre
power supply to be considered, whether considering final energy (e.g. for KPIs) or primary energy (e.g. in an EPB
approach).
5 Data centre assessment boundary
5.1 Data centre boundary in the ISO/IEC 30134 series
The ISO/IEC 30134 series considers the boundary of a data centre being crossed by the relevant energy
flows in order to determine energy-related KPIs. Energy flows can be metered at this boundary. Flows
and boundaries are illustrated in Figure 1.
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ISO/IEC TR 21897:2022(E)
Key
electrical energy
thermal energy
re-useable energy
other energy
Figure 1 — Schema representing the concept of a data centre boundary and energy flows
For the purpose of this document E , E and E are detailed in Clause 8.
DC excess reuse
5.2 Assessment boundary of the system in the ISO 52000 series
In the EPB approach from the ISO 52000 series, the assessment boundary is related to the assessed
object (e.g. data centre, data centre spaces, systems or sub-systems).
Inside the assessment boundary the system losses are explicitly taken into account in the energy
balance; outside the assessment boundary they are taken into account in the conversion factor applied
to the energy carrier.
Energy can be imported or exported through the assessment boundary. The assessment boundary
defines the overall energy balance.
Some of these energy flows
...