ISO 18566-4:2017

INTERNATIONAL ISO
STANDARD 18566-4
First edition
2017-06
Building environment design —
Design, test methods and control of
hydronic radiant heating and cooling
panel systems —
Part 4:
Control of ceiling mounted radiant
heating and cooling panels
Conception de l’environnement des bâtiments — Conception,
méthodes d’essai et contrôle des systèmes de panneaux hydroniques
radiants de chauffage et de refroidissement —
Partie 4: Contrôle des panneaux radiants de chauffage et de
refroidissement montés au plafond
Reference number
ISO 18566-4:2017(E)
©
ISO 2017

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ISO 18566-4:2017(E)

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© ISO 2017, Published in Switzerland
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ISO 18566-4:2017(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Controls . 1
5.1 General . 1
5.2 Central control . 4
5.3 Zone control . 5
5.4 Local (space) control . 5
5.5 Influence of thermal mass of panel systems. 5
5.6 Self-regulating effect . 5
5.7 Flow control. 6
Annex A (informative) Control of ceiling mounted radiant panel cooling system for
prevention of surface condensation . 7
Bibliography . 8
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ISO 18566-4:2017(E)

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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO 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).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
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URL: w w w . i s o .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 205, Building environment design.
A list of all parts in the ISO 18566 series can be found on the ISO website.
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ISO 18566-4:2017(E)

Introduction
The radiant heating and cooling system consists of heat emitting/absorbing, heat supply, distribution,
and control systems. Typical applications are low temperature radiant heating and high temperature
radiant cooling. They are classified as embedded radiant heating and cooling systems and prefabricated
radiant heating and cooling panel systems.
While ISO 11855 is for embedded radiant heating and cooling systems without an open air gap,
ISO 18566 is for radiant heating and cooling panel systems with an open air gap. Because the system
specifications for ISO 18566 are different from those of ISO 11855, it was necessary to develop separate
ISO standards regarding the design and test methods of the cooling and heating capacity and control
and operation.
ISO 18566-1 specifies the comfort criteria, technical specifications and requirements which should be
considered in the manufacturing and installation of radiant heating and cooling systems. ISO 18566-2
provides the test facility and test method for heating and cooling capacity of ceiling mounted radiant
panels. ISO 18566-3 specifies the design considerations and design processes of ceiling mounted radiant
panels. ISO 18566-4 addresses the control of ceiling mounted radiant heating and cooling panels to
ensure the maximum performance which was intended in the design stage when the system is actually
being operated in a building.
ISO 18566 does not cover the panels that are embedded into the ceiling, wall or floor structure.
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INTERNATIONAL STANDARD ISO 18566-4:2017(E)
Building environment design — Design, test methods and
control of hydronic radiant heating and cooling panel
systems —
Part 4:
Control of ceiling mounted radiant heating and cooling
panels
1 Scope
This document specifies the control of ceiling mounted radiant heating and cooling panels. The
requirements in this document are applicable only to the components of the heating/cooling systems
and the elements which are part of the heating/cooling panels and which are installed to provide
heating and/or cooling.
This document is applicable to water-based ceiling mounted radiant heating and cooling panels in
residential, commercial and industrial buildings. The methods apply to systems mounted under the
ceiling with or without open air gaps between the panels and the ceiling.
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 18566-1, Building environment design — Design, test methods and control of hydronic radiant heating
and cooling panel systems — Part 1: Definition, symbols, technical specifications and requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18566-1 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Symbols
For the purposes of this document, the symbols in ISO 18566-1 apply.
5 Controls
5.1 General
This clause describes the control of hydronic systems to enable all radiant panel systems to perform
as simulated. The design documents shall include specifications for the control system. The control
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ISO 18566-4:2017(E)

system shall be capable of varying heating or cooling outputs as well as maintaining predetermined
room or surface temperatures.
Control of the heating and cooling system shall enable the specified designed indoor temperatures to
be achieved under the specified variation of internal loads and external climate. The control system
shall, if specified, protect buildings and equipment against frost and moisture damage where necessary
(when normal comfort temperature level is not required) and prevent condensation from occurring.
The design of the control system shall take into account the dynamics of the space, its intended use
and the effective functioning of the panel system. It shall also ensure efficient use of energy and
avoid conditioning the space to full design conditions when not required. This shall include keeping
distribution heat losses as low as possible, e.g. by reducing flow rates and temperatures, when normal
comfort temperature level is not required. Control of the system will enable control of the conditioning
systems to obtain possible savings of operational costs and enable the maintenance of required indoor
environmental conditions. The control shall ensure that heating and cooling does not occur at the same
time in the same space.
In order to maintain a stable thermal environment, the control system needs to maintain the balance
between supplied energy from the system and the losses/gains of the space environment under
transient conditions. Slowly varying energy flows in the form of energy losses or gains through the
envelope are determined by indoor and outdoor temperature, and direction and speed of wind.
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ISO 18566-4:2017(E)

Key
B boiler OTS outside temperature sensor
C chiller P pump
CU control unit RS room sensor
PTS panel temperature sensor RTS return medium temperature sensor
L limiter SOV shut off valve
M manifold STS supply medium temperature sensor
MC main controller THS temperature-humidity sensor
MV mixing valve
Figure 1 — Principal diagram of a radiant ceiling panel system for heating and cooling
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ISO 18566-4:2017(E)

Figure 1 s
...