ISO 18483

Performance rating of centrifugal refrigerant compressor

This proposed standard specifies the terms and definitions, classification basic parameters, test rating requirements, marking, packaging and storage of centrifugal refrigerant compressor. The standard is applicable to centrifugal refrigerant compressors for air-conditioning and heat pump purposes. Centrifugal refrigerant compressors for other purposes are implemented by reference.

Détermination des performances des compresseurs frigorifiques centrifuges

General Information

• Status: Not Published
• ICS: 27.200 - Refrigerating technology
• Technical Committee: ISO/TC 86/SC 4 - Testing and rating of refrigerant compressors
• Drafting Committee: ISO/TC 86/SC 4 - Testing and rating of refrigerant compressors
• Current Stage: 6000 - International Standard under publication
• Due Date: 07-Mar-2025
• Completion Date: 07-Mar-2025

Standards Content (Sample)

International
Standard
First edition
Performance rating of centrifugal
refrigerant compressor
PROOF/ÉPREUVE
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
PROOF/ÉPREUVE
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Rating requirements . 3
4.1 General requirements .3
4.2 Rating methods .4
4.3 Rating conditions .4
4.4 Power supply requirements .5
5 Published rating . 5
5.1 Reference rating .5
5.2 Performance data .5
5.3 Application envelope .5
5.4 Published data.6
5.5 Tolerance .6
6 Marking provisions . 8
Annex A (informative) Example for the performance data . 9
Bibliography .10
PROOF/ÉPREUVE
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
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 ISO 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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.
This document was prepared by Technical Committee ISO/TC 86, Refrigeration and air-conditioning,
Subcommittee SC 4, Testing and rating of refrigerant compressors.
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.
PROOF/ÉPREUVE
iv
International Standard ISO 18483:2025(en)
Performance rating of centrifugal refrigerant compressor
1 Scope
This document specifies the rating requirements, published ratings and marking provisions of centrifugal
refrigerant compressors. This document applies to centrifugal compressors and their performance in
heating, ventilation and air-conditioning applications.
This document provides guidance and requirements for the industry, including manufacturers, engineers,
installers and contractors. It defines the minimum amount of information in a standardized form to enable
the evaluation and comparison of different compressors for use in an application and suggests a method to
be used to guarantee the accuracy of that information.
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 18976, Testing of refrigerant compressors
IEC 60038, IEC standard voltages
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
centrifugal refrigerant compressor
compressor relying on the impeller to increase the pressure and kinetic energy of the refrigerant vapour
before a portion of the kinetic energy is converted into pressure in the diffuser
Note 1 to entry: In this document, the term compressor implies centrifugal refrigerant compressor.
3.2
refrigerating capacity
product of the refrigerant mass flow at the compressor inlet port and the difference between the specific
refrigerant enthalpy at the compressor inlet port and the specific enthalpy of fluid entering the evaporator
expansion device
3.3
economizer
heat exchanger or flash tank that is used to lower the liquid specific enthalpy of the refrigerant entering the
evaporator while producing vapour that is reintroduced to the compression process
PROOF/ÉPREUVE
3.4
head factor
HF
ratio of isentropic enthalpy rise at each stage of the compressor to the square of suction sonic velocity
Note 1 to entry: This is a dimensionless parameter.
3.5
heating capacity
product of the refrigerant mass flow leaving the compressor discharge port and the difference of the specific
refrigerant enthalpy at the discharge port and the outlet of the condenser or gas cooler
3.6
heating coefficient of performance
C
OPh
ratio of heating thermal capacity to the power input
Note 1 to entry: This is a dimensionless parameter.
3.7
application envelope
allowable operation range of the compressor based on the suction dew-point and discharge dew-point
3.8
overall compressor efficiency
η
all
ratio of the isentropic enthalpy rise multiplied by the mass flow to the power input of the compressor
Note 1 to entry: This is a dimensionless parameter.
3.9
power input
time rate of energy usage of the compressor plus any accessories required to sustain operation of the
compressor at the rating condition
3.10
pressure ratio
π
ratio of the absolute discharge pressure to the absolute suction pressure of the compressor or compression stage
Note 1 to entry: This is a dimensionless parameter.
3.11
refrigerating coefficient of performance
C
OPr
ratio of refrigerating capacity to the power input
3.12
refrigerant flow factor
FF
ratio of suction volumetric flow of the compressor to the suction sonic velocity
Note 1 to entry: The flow coefficient excludes an impeller diameter squared term in the denominator to avoid exposing
proprietary dimensional information, therefore the units of measure are area (expressed in m ).
Note 2 to entry: This is a dimensionless parameter.
3.13
stage
basic unit of centrifugal compressor, which is composed of an impeller and its matching fixed elements that
works on the gas and realizes an energy increase
PROOF/ÉPREUVE
3.14
subcooling
difference between the bubble point temperature of the refrigerant corresponding to its pressure and the
temperature of the liquid refrigerant
3.15
superheat
difference between the temperature of the vapour refrigerant and its dew-point temperature corresponding
to its pressure
3.16
continuous modulating compressor
compressor with more than four displacement capacities or infinitely variable displacement capacities
Note 1 to entry: This includes but is not limited to variable speed, continuously variable mechanical unloading or
cyclic modulation of discrete.
3.17
discrete modulating compressor
compressor with two to four discrete displacement capacities
3.18
fixed modulation compressor
compressor with only one step
3.19
step
level of modulation achieved by changing the manufacturer defined operational setpoints
3.20
maximum step
maximum level of modulation defined by the manufacturer
3.21
minimum step
minimum level of modulation defined by the manufacturer
3.22
reduced step
level of modulation defined by the manufacturer which is less than the maximum step
3.23
publish
transfer information to any entity decided by the manufacturer
4 Rating requirements
4.1 General requirements
All published ratings shall be based on tests conducted in accordance with ISO 18976.
Published ratings shall be established with an ambient temperature of 35 °C around the compressor and
its accessories. If rating at ambient temperatures other than 35 °C, the actual ambient temperature used to
establish the rating shall be stated by the manufacturer.
The manufacturer is solely responsible for the determination of values to be used in published product
information.
PROOF/ÉPREUVE
4.2 Rating methods
Compressor performance data are provided in the context of a vapour compression cycle with the following
assumptions and requirements.
a) For all methods, other than mechanical sub-cooling in the economizer, parasitic heat gain or loss in the
liquid line shall be assumed to be zero.
b) Liquid temperature leaving the condenser shall be assumed to have 0 K subcooling unless otherwise
stated by the manufacturer.
c) The manufacturer shall specify the outlet liquid temperature of the economizer or the temperature
difference between the liquid leaving the economizer and the injected refrigerant entering the
intermediate heat exchanger.
d) Vapour temperature leaving the economizer shall be assumed to have superheat corresponding to the
pressure at the intermediate or interstage port of the compressor as follows:
1) superheat as declared by the manufacturer when rated with a specified heat exchanger as
economizer;
2) 5 K superheat when rated with a non-specified heat exchanger as economizer;
3) 0 K superheat when rated with a flash tank as economizer.
Unless other
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ISO /TC 86/SC 4
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Performance rating of centrifugal refrigerant compressor
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PROOF
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, Formatted: Indent: Left: 0 cm, Right: 0 cm, Space
Before: 0 pt, No page break before, Adjust space
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
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at the address below or ISO’s member body in the country of the requester.
Asian text and numbers
ISO copyright office
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CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Formatted: French (Switzerland)
EmailE-mail: [e-mail]
Formatted: French (Switzerland)
Website: www.iso.orgwww.iso.org
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Published in Switzerland
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ii © ISO #### 2025 – All rights reserved
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ii
ISO/DISPRF 18483:20242025(en) Formatted: Font: 11 pt, Bold
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Contents
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Foreword . iv
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1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Rating requirements . 4
5 Published rating . 6
6 Marking provisions . 10
Annex A (informative) Example for the performance data . 11
Bibliography . 13

Foreword . iv
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 Rating requirements .4
4.1 General requirements .4
4.2 Rating methods .4
4.3 Rating conditions .5
4.4 Power supply requirements .5
5 Published rating .5
5.1 Reference rating .5
5.2 Performance data .6
5.3 Application envelope .6
5.4 Published data .6
5.5 Tolerance .7
6 Marking provisions .8
Annex A (informative) Example for the performance data . 10
A.1 General . 10
Bibliography . 10

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iii
ISO/PRF 18483:####(X:2025(en) Formatted: Font: 11 pt, Bold
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Foreword
spacing: single
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ISO (the International Organization for Standardization) is a worldwide federation of national standards
Formatted: Adjust space between Latin and Asian text,
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
Adjust space between Asian text and numbers
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
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
ISO 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).
Formatted: English (United Kingdom)
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 86, Refrigeration and air-conditioning,
Formatted: Adjust space between Latin and Asian text,
Subcommittee SC 4, Testing and rating of refrigerant compressors. Adjust space between Asian text and numbers
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.
Formatted: Hyperlink
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iv © ISO #### 2025 – All rights reserved
Classified as Business
iv
ISO/PRF 18483:2025(en)
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Performance rating of centrifugal refrigerant compressor
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1 Scope
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This document specifies the normative reference, terms and definitions, rating requirements, published
Formatted: English (United Kingdom)
ratingratings and marking provisionprovisions of centrifugal refrigerant compressorcompressors. This
Formatted: English (United Kingdom)
document applies to centrifugal compressors and their presentation of performance in heating, ventilation
Formatted: Adjust space between Latin and Asian text,
and air-conditioning applications. The manufacturer is solely responsible for the determination of values to
Adjust space between Asian text and numbers
be used in published product information.
Formatted: English (United Kingdom)

Formatted: English (United Kingdom)
This document provides guidance and requirements for the industry, including manufacturers, engineers, Formatted: English (United Kingdom)
installers and contractors. It defines the minimum amount of information in a standardstandardized form to
Formatted: Adjust space between Latin and Asian text,
enable the evaluation and comparison of different compressors for use in an application and suggests a
Adjust space between Asian text and numbers
method to be used to guarantee the accuracy of that information.
Formatted: English (United Kingdom)
2 Normative references
Formatted: Default Paragraph Font
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,
Formatted: Default Paragraph Font
the latest edition of the referenced document (including any amendments) applies.
Formatted: Default Paragraph Font, Font: Italic
ISO 18976, Testing of refrigerant compressors Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers, Tab
IEC 60038, IEC standard voltages stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
3 Terms and definitions
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For the purposes of this document, the following terms and definitions given in ISO 18976 and the following
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apply.
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ISO and IEC maintain terminologicalterminology databases for use in standardization at the following
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addresses:
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers, Tab
— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
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and Asian text, Adjust space between Asian text and
3.1 3.1
numbers
centrifugal refrigerant compressor
compressor relying on the impeller to do work on the refrigerant vapour to increase the pressure and kinetic
Formatted: English (United Kingdom)
energy of the refrigerant vapour before a portion of the kinetic energy is converted into pressure in the
Formatted: English (United Kingdom)
diffuser
Formatted: English (United Kingdom)
Note 1 to Entry: For clarity of entry: In this document, the term compressor implies centrifugal refrigerant compressor.
Formatted: English (United Kingdom)
Formatted: Font: 10 pt
3.2 3.2
refrigerating capacity
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product of the refrigerant mass flow at the compressor inlet port and the difference between the specific
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refrigerant enthalpy at the compressor inlet port and the specific enthalpy of fluid entering the evaporator
Formatted: Font: Not Bold
expansion device
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ISO/PRF 18483:2025(en)
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