SIST EN ISO 11855-4:2015
(Main)Building environment design - Design, dimensioning, installation and control of embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) (ISO 11855-4:2012)
Building environment design - Design, dimensioning, installation and control of embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) (ISO 11855-4:2012)
This European Standard is applicable to water based embedded surface heating and cooling systems in residential, commercial and industrial buildings.
The methods apply to systems integrated into the wall, floor or ceiling construction without any open air gaps.
The methods do not apply to heated or chilled ceiling panels or beams.
The aim of the present standard is not the evaluation of cooling load for dynamic simulations, but to give a guide for dimensioning Thermo Active Building Systems (TABS), which can enable the use of renewable energy sources.
This Standard allows the calculation of peak cooling capacity of a thermo active building system (based on heat gains, such as solar gains, internal heat gains, and ventilation), and the calculation of the cooling power demand on the water side to be used to size the cooling system, as regards the chiller size, fluid flow rate, etc. This standard defines even a detailed method aimed at the calculation of heating and cooling capacity in unsteady state conditions. Steady state heating capacity is calculated according to method B or E in Part 2 of this series of standards instead.
Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 4: Auslegung und Berechnung der dynamischen Wärme- und Kühlleistung für thermoaktive Bauteilsysteme (TABS) (ISO 11855-4:2012)
Conception de l'environnement des bâtiments - Conception, construction et fonctionnement des systèmes de chauffage et de refroidissement par rayonnement - Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique et à la puissance frigorifique pour systèmes thermoactifs (TABS) (ISO 11855-4:2012)
ISO 11855-4:2012 permet de calculer la puissance frigorifique de pointe de systèmes d'éléments de construction thermoactifs (TABS) en se fondant sur les apports de chaleur, tels que les apports solaires, les apports de chaleur internes et la ventilation, ainsi que de calculer la demande en puissance frigorifique côté eau, afin de les utiliser pour dimensionner le système de refroidissement en ce qui concerne les dimensions du refroidisseur, le débit de fluide, etc.
La présente partie de l'ISO 11855 présente une méthode détaillée visant à calculer la puissance calorifique et frigorifique dans des conditions non stabilisées.
La série ISO 11855 s'applique aux systèmes de chauffage et de refroidissement de surface intégrés à eau dans les bâtiments résidentiels, commerciaux et industriels. Ces méthodes s'appliquent aux systèmes intégrés dans les murs, sols ou plafonds, sans ouverture à l'air libre. Elles ne s'appliquent pas aux systèmes de panneaux avec ouvertures à l'air libre, qui ne sont pas intégrés dans une structure de bâtiment.
La série ISO 11855 s'applique également, le cas échéant, à l'utilisation d'autres fluides que l'eau en tant que medium de chauffage ou de refroidissement. La série ISO 11855 ne s'applique pas à l'essai des systèmes. Ces méthodes ne s'appliquent pas aux panneaux ou poutres de plafond chauffés ou refroidis.
Načrtovanje gradnje - Načrtovanje, dimenzioniranje, montaža in kontrola vgrajenih hladilnih in ogrevalnih sistemov - 4. del: Dimenzioniranje in izračun zmogljivosti dinamičnega ogrevanja in hlajenja termoaktivnega gradbenega sistema (TAGS)" (ISO 11855-4:2012)
Ta evropski standard se uporablja za vgrajene ploskovne sisteme za ogrevanje in hlajenje z vodo v stanovanjskih, poslovnih ter industrijskih stavbah. Metode se uporabljajo za sisteme, vgrajene v stensko, talno ali stropno konstrukcijo brez odprtih vmesnih zračnih prostorov. Metode se ne uporabljajo za ogrevane ali hlajene stropne plošče ali tramove. Cilj tega standarda ni ocena hladilne obremenitve za dinamične simulacije, ampak zagotoviti navodilo za dimenzioniranje termoaktivnega gradbenega sistema (TABS), ki lahko omogoči uporabo obnovljivih virov energije. Ta standard omogoča izračun vršne zmogljivosti hlajenja termoaktivnega gradbenega sistema (na podlagi toplotnih dobičkov, kot so solarni dobički, notranji toplotni dobički in prezračevanje) in izračun zahteve glede moči hlajenja v zvezi z vodo, ki se uporablja za ocenjevanje hladilnega sistema, kar zadeva velikost naprave za hlajenje, hitrost pretoka tekočine itd. Ta standard določa celo podrobno metodo za izračun zmogljivosti ogrevanja in hlajenja v neustaljenih pogojih. Ustaljena zmogljivost ogrevanja se namesto tega izračuna v skladu z metodo B ali E v 2. delu te skupine standardov.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11855-4:2015
01-oktober-2015
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SIST EN 15377-3:2007
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KODGLOQLKLQRJUHYDOQLKVLVWHPRYGHO 'LPHQ]LRQLUDQMHLQL]UDþXQ]PRJOMLYRVWL
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Building environment design - Design, dimensioning, installation and control of
embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of
the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS)
(ISO 11855-4:2012)
Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung
flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 4: Auslegung und
Berechnung der dynamischen Wärme- und Kühlleistung für thermoaktive Bauteilsysteme
(TABS) (ISO 11855-4:2012)
Conception de l'environnement des bâtiments - Conception, construction et
fonctionnement des systèmes de chauffage et de refroidissement par rayonnement -
Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique et à la puissance
frigorifique pour systèmes thermoactifs (TABS) (ISO 11855-4:2012)
Ta slovenski standard je istoveten z: EN ISO 11855-4:2015
ICS:
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
91.140.30 3UH]UDþHYDOQLLQNOLPDWVNL Ventilation and air-
VLVWHPL conditioning
SIST EN ISO 11855-4:2015 en,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11855-4:2015
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SIST EN ISO 11855-4:2015
EUROPEAN STANDARD
EN ISO 11855-4
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2015
ICS 91.140.10; 91.140.30 Supersedes EN 15377-3:2007
English Version
Building environment design - Design, dimensioning, installation
and control of embedded radiant heating and cooling systems -
Part 4: Dimensioning and calculation of the dynamic heating and
cooling capacity of Thermo Active Building Systems (TABS)
(ISO 11855-4:2012)
Conception de l'environnement des bâtiments - Conception, Umweltgerechte Gebäudeplanung - Planung, Auslegung,
construction et fonctionnement des systèmes de chauffage Installation und Steuerung flächenintegrierter
et de refroidissement par rayonnement - Partie 4: Strahlheizungs- und -kühlsysteme - Teil 4: Auslegung und
Dimensionnement et calculs relatifs au chauffage Berechnung der dynamischen Wärme- und Kühlleistung für
adiabatique et à la puissance frigorifique pour systèmes thermoaktive Bauteilsysteme (TABS) (ISO 11855-4:2012)
thermoactifs (TABS) (ISO 11855-4:2012)
This European Standard was approved by CEN on 30 July 2015.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11855-4:2015 E
worldwide for CEN national Members.
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SIST EN ISO 11855-4:2015
EN ISO 11855-4:2015 (E)
Contents Page
European foreword .3
2
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SIST EN ISO 11855-4:2015
EN ISO 11855-4:2015 (E)
European foreword
The text of ISO 11855-4:2012 has been prepared by Technical Committee ISO/TC 205 “Building environment
design” of the International Organization for Standardization (ISO) and has been taken over as EN ISO
11855-4:2015 by Technical Committee CEN/TC 228 “Heating systems and water based cooling systems in
buildings” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by February 2016, and conflicting national standards shall be withdrawn
at the latest by February 2016.
This standard is applicable for design, construction and operation of radiant heating and cooling systems. The
methods defined in part 2 are intended to determine the design heating or cooling capacity used for the design
and evaluation of the performance of the system.
For identifying product characteristics by testing and proving the thermal output of heating and cooling
surfaces embedded in floors, ceilings and walls the standard series EN 1264 can be used.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 15377-3:2007.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 11855-4:2012 has been approved by CEN as EN ISO 11855-4:2015 without any modification.
3
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SIST EN ISO 11855-4:2015
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SIST EN ISO 11855-4:2015
INTERNATIONAL ISO
STANDARD 11855-4
First edition
2012-08-01
Building environment design — Design,
dimensioning, installation and control of
embedded radiant heating and cooling
systems —
Part 4:
Dimensioning and calculation of the
dynamic heating and cooling capacity of
Thermo Active Building Systems (TABS)
Conception de l'environnement des bâtiments — Conception,
construction et fonctionnement des systèmes de chauffage et de
refroidissement par rayonnement —
Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique
et à la puissance frigorifique pour systèmes thermoactifs (TABS)
Reference number
ISO 11855-4:2012(E)
©
ISO 2012
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Contents Page
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviations . 1
5 The concept of Thermally Active Surfaces (TAS) . 6
6 Calculation methods . 11
6.1 General . 11
6.2 Rough sizing method . 12
6.3 Simplified sizing by diagrams . 13
6.4 Simplified model based on finite difference method (FDM) . 19
6.4.1 Cooling system . 20
6.4.2 Hydraulic circuit and slab . 20
6.4.3 Room . 22
6.4.4 Limits of the method . 24
6.5 Dynamic building simulation programs . 25
7 Input for computer simulations of energy performance . 25
Annex A (informative) Simplified diagrams . 26
Annex B (normative) Calculation method . 31
B.1. Pipe level . 31
B.2. Thermal nodes composing the slab and room . 31
B.3. Calculations for the generic h-th hour . 35
B.4 Sizing of the system . 41
Annex C (informative) Tutorial guide for assessing the model . 42
Annex D (informative) Computer program . 44
Bibliography . 52
© ISO 2012 – All rights reserved iii
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 11855-4 was prepared by Technical Committee ISO/TC 205, Building environment design.
ISO 11855 consists of the following parts, under the general title Building environment design — Design,
dimensioning, installation and control of embedded radiant heating and cooling systems:
— Part 1: Definition, symbols, and comfort criteria
— Part 2: Determination of the design and heating and cooling capacity
— Part 3: Design and dimensioning
— Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active
Building Systems (TABS)
— Part 5: Installation
— Part 6: Control
Part 1 specifies the comfort criteria which should be considered in designing embedded radiant heating and
cooling systems, since the main objective of the radiant heating and cooling system is to satisfy thermal
comfort of the occupants. Part 2 provides steady-state calculation methods for determination of the heating
and cooling capacity. Part 3 specifies design and dimensioning methods of radiant heating and cooling
systems to ensure the heating and cooling capacity. Part 4 provides a dimensioning and calculation method to
design Thermo Active Building Systems (TABS) for energy-saving purposes, since radiant heating and cooling
systems can reduce energy consumption and heat source size by using renewable energy. Part 5 addresses
the installation process for the system to operate as intended. Part 6 shows a proper control method of the
radiant heating and cooling systems to ensure the maximum performance which was intended in the design
stage when the system is actually being operated in a building.
iv © ISO 2012 – All rights reserved
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Introduction
The radiant heating and cooling system consists of heat emitting/absorbing, heat supply, distribution, and
control systems. The ISO 11855 series deals with the embedded surface heating and cooling system that
directly controls heat exchange within the space. It does not include the system equipment itself, such as heat
source, distribution system and controller.
The ISO 11855 series addresses an embedded system that is integrated with the building structure.
Therefore, the panel system with open air gap, which is not integrated with the building structure, is not
covered by this series.
The ISO 11855 series shall be applied to systems using not only water but also other fluids or electricity as a
heating or cooling medium.
The object of the ISO 11855 series is to provide criteria to effectively design embedded systems. To do this, it
presents comfort criteria for the space served by embedded systems, heat output calculation, dimensioning,
dynamic analysis, installation, operation, and control method of embedded systems.
© ISO 2012 – All rights reserved v
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SIST EN ISO 11855-4:2015
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SIST EN ISO 11855-4:2015
INTERNATIONAL STANDARD ISO 11855-4:2012(E)
Building environment design — Design, dimensioning,
installation and control of embedded radiant heating and
cooling systems —
Part 4:
Dimensioning and calculation of the dynamic heating and
cooling capacity of Thermo Active Building Systems (TABS)
1 Scope
This part of ISO 11855 allows the calculation of peak cooling capacity of Thermo Active Building Systems
(TABS), based on heat gains, such as solar gains, internal heat gains, and ventilation, and the calculation of
the cooling power demand on the water side, to be used to size the cooling system, as regards the chiller size,
fluid flow rate, etc.
This part of ISO 11855 defines a detailed method aimed at the calculation of heating and cooling capacity in
non-steady state conditions.
The ISO 11855 series is applicable to water based embedded surface heating and cooling systems in
residential, commercial and industrial buildings. The methods apply to systems integrated into the wall, floor or
ceiling construction without any open air gaps. It does not apply to panel systems with open air gaps which
are not integrated into the building structure.
The ISO 11855 series also applies, as appropriate, to the use of fluids other than water as a heating or cooling
medium. The ISO 11855 series is not applicable for testing of systems. The methods do not apply to heated or
chilled ceiling panels or beams.
2 Normative references
The following referenced documents are indispensable for the application 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 11855-1, Building environment design — Design, dimensioning, installation and control of embedded
radiant heating and cooling systems — Part 1: Definition, symbols, and comfort criteria
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 11855-1 apply.
4 Symbols and abbreviations
For the purposes of this part of ISO 11855, the symbols and abbreviations in Table 1 apply:
© ISO 2012 – All rights reserved 1
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Table 1 — Symbols and abbreviations
Symbol Unit Quantity
2
A
m Area of the heating/cooling surface area
F
2
A m Total area of internal vertical walls (i.e. vertical walls, external façades excluded)
W
2
C J/(m ·K) Specific thermal capacity of the thermal node under consideration
2
C J/(m ·K) Average specific thermal capacity of the internal walls
W
c
J/(kg·K) Specific heat of the material constituting the j-th layer of the slab
j
c
J/(kg·K) Specific heat of water
w
d
m External diameter of the pipe
a
2
E kWh/m Specific daily energy gains
Day
Running mode (1 when the system is running; 0 when the system is switched off) in the
h
f
-
rm
h-th hour
f - Design safety factor
s
F
- View factor between the floor and the ceiling
v F-C
F
- View factor between the floor and the external walls
v F-EW
F
- View factor between the floor and the internal walls
v F-W
2
h W/(m ·K) Convective heat transfer coefficient between the air and the ceiling
A-C
2
h
W/(m ·K) Convective heat transfer coefficient between the air and the floor
A-F
2
h
W/(m ·K) Convective heat transfer coefficient between the air and the internal walls
A-W
2
h
W/(m ·K) Radiant heat transfer coefficient between the floor and the ceiling
F-C
2
h W/(m ·K) Radiant heat transfer coefficient between the floor and the internal walls
F-W
Heat transfer coefficient between the thermal node under consideration and the air
H W/K
A
thermal node (“A”)
Heat transfer coefficient between the thermal node under consideration and the ceiling
H W/K
C
surface thermal node (“C”)
H W/K Heat transfer coefficient between the thermal node under consideration and the circuit
Circuit
H W/K Heat transfer coefficient between the thermal node under consideration and the next one
CondDown
Heat transfer coefficient between the thermal node under consideration and the previous
H W/K
CondUp
one
H - Fraction of internal convective heat gains acting on the thermal node under consideration
Conv
Heat transfer coefficient between the thermal node under consideration and the floor
H W/K
F
surface thermal node (“F”)
H W/K Coefficient connected to the inertia contribution at the thermal node under consideration
Inertia
Heat transfer coefficient between the thermal node under consideration and the internal
H W/K
IWS
wall surface thermal node (“IWS”)
H - Fraction of total radiant heat gains impinging on the thermal node under consideration
Rad
2
h
W/(m ·K) Total heat transfer coefficient (convection + radiation) between surface and space
t
J - Number of layers constituting the slab as a whole
2 © ISO 2012 – All rights reserved
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Symbol Unit Quantity
J
- Number of layers constituting the upper part of the slab
1
J
- Number of layers constituting the lower part of the slab
2
L
m Length of installed pipes
R
2
m
kg/(m ·s) Specific water flow in the circuit, calculated on the area covered by the circuit
H,sp
m
- Number of partitions of the j-th layer of the slab
j
n - Actual number of iteration in iterative calculations
n h Number of operation hours of the circuit
h
Max
n - Maximum number of iterations allowed in iterative calculations
Max,h
P W Maximum cooling power reserved to the circuit under consideration in the h-th hour
Circuit
Max 2
P W/m Maximum specific cooling power (per floor square metre)
Circuit,Spec
2
q W/m Inward specific heat flow
i
2
q W/m Outward specific heat flow
u
h
Q W Heat flow impinging on the ceiling surface (“C”) in the h-th hour
C
h
Q W Heat flow extracted by the circuit in the h-th hour
Circuit
h
Q
W Total convective heat gains in the h-th hour
Conv
h
Q W Heat flow impinging on the floor surface (“F”) in the h-th hour
F
h
Q W Internal convective heat gains in the h-th hour
IntConv
h
Q W Internal radiant heat gains in the h-th hour
IntRad
h
Q
W Heat flow impinging on the internal wall surface (“IWS”) in the h-th hour
IWS
h
Q W Primary air convective heat gains in the h-th hour
PrimAir
h
Q W Total radiant heat gains in the h-th hour
Rad
h
Q W Solar heat gains in the room in the h-th hour
Sun
h
Q
W Transmission heat gains in the h-th hour
Transm
2
Q
W/m Average specific cooling power
W
2
R (m ·K)/W Generic thermal resistance
2
R
(m ·K)/W Additional thermal resistance covering the lower side of the slab
Add C
2
R
(m ·K)/W Additional thermal resistance covering the upper side of the slab
Add F
Convection thermal resistance connecting the air thermal node (“A”) with the ceiling
RCAC K/W
surface thermal node (“C”)
Convection thermal resistance connecting the air thermal node (“A”) with the floor surface
RCAF K/W
thermal node (“F”)
Convection thermal resistance connecting the air thermal node (“A”) with the internal wall
RCAW K/W
surface thermal node (“IWS”)
© ISO 2012 – All rights reserved 3
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Symbol Unit Quantity
2
R (m ·K)/W Internal thermal resistance of the slab conductive region
int
Conduction thermal resistance connecting the p-th thermal node with the boundary of the
2
R (m ·K)/W
L,p
(p+1)-th thermal node
2
R
(m ·K)/W Pipe thickness thermal resistance
r
Radiation thermal resistance connecting the floor surface thermal node (“F”) with the
RRFC K/W
ceiling surface thermal node (“C”)
Radiation thermal resistance connecting the internal wall surface thermal node (“IWS”)
RRWC K/W
with the ceiling surface thermal node (“C”)
Radiation thermal resistance connecting the internal wall surface thermal node (“IWS”)
RRWF K/W
with the floor surface thermal node (“F”)
2
R (m ·K)/W Circuit total thermal resistance
t
Conduction thermal resistance connecting the p-th thermal node with the boundary of the
2
R (m ·K)/W
U,p
(p-1)-th thermal node
2
R
(m ·K)/W Wall surface thermal resistance
Walls
2
R
(m ·K)/W Water flow thermal resistance
w
2
R
(m ·K)/W Pipe level thermal resistance
x
2
R (m ·K)/W Convection thermal resistance at the pipe inner side
z
s
m Pipe wall thickness
r
s
m Thickness of the upper part of the slab
1
s
m Thickness of the lower part of the slab
2
W m Pipe spacing
δ
m Thickness of the j-th layer of the slab
j
K Generic temperature difference
Max
K Maximum operative temperature drift allowed for comfort conditions
Comfort
t s Calculation time step
h
°C Temperature of the air thermal node (“A”) in the h-th hour
A
h
°C Temperature of the ceiling surface thermal node (“C”) in the h-th hour
C
Max
°C Maximum operative temperature allowed for comfort conditions
Comfort
°C Maximum operative temperature allowed for comfort conditions in the reference case
Comfort,Ref
h
°C Temperature of the floor surface thermal node (“F”) in the h-th hour
F
h
°C Temperature of the core of the internal walls thermal node (“IW”) in the h-th hour
IW
h
°C Temperature of the internal wall surface thermal node (“IWS”) in the h-th hour
IWS
h
°C Room mean radiant temperature in the h-th hour
MR
h
°C Room operative temperature in the h-th hour
Op
4 © ISO 2012 – All rights reserved
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SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Symbol Unit Quantity
h
°C Temperature of the p-th thermal node in the h-th hour
p
h
°C Temperature of the pipe level thermal node (“PL”) in the h-th hour
PL
Av
°C Daily average temperature of the conductive region of the slab
Slab
h
°C Water inlet actual temperature in the h-th hour
Water,In
Setp,h
°C Water inlet set-point temperature in the h-th hour
Water,In
Setp
°C Water inlet set-point temperature in the reference case
Water,In,Ref
h
°C Water outlet temperature in the h-th hour
Water,Out
W/(m·K) Thermal conductivity of the material of the pipe embedded layer
b
λ
W/(m·K) Thermal conductivity of the material constituting the j-th layer of the slab
j
W/(m·K) Thermal conductivity of the material constituting the pipe
r
K Actual tolerance in iterative calculations
K Maximum tolerance allowed in iterative calculations
Max
3
kg/m Density of the material constituting the j-th layer of the slab
j
various Slope of correlation curves
© ISO 2012 – All rights reserved 5
---------------------- Page: 17 ----------------------
SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
5 The concept of Thermally Active Surfaces (TAS)
A Thermally Active Surface (TAS) is an embedded water based surface heating and cooling system, where
the pipe is embedded in the central concrete core of a building construction (see Figure 1).
Key
C concrete
F floor
P pipes
R room
RI reinforcement
W window
Figure 1 — Example of position of pipes in TAS
The building constructions embedding the pipe are usually the horizontal ones. As a consequence, in the
following sections, floors and ceilings are usually referred to as active surfaces. Looking at a typical structure
of a TAS, heat is removed by a cooling system (for instance, a chiller), connected to pipes embedded in the
slab. The system can be divided into the elements shown in Figure 2.
6 © ISO 2012 – All rights reserved
---------------------- Page: 18 ----------------------
SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Key
1 heating/cooling equipment
2 hydraulic circuit
3 slab including core layer with pipes
4 possible additional resistances (floor covering or suspended ceiling)
5 room below and room above
PL pipe level
Figure 2 — Simple scheme of a TAS
Thermally active surfaces exploit the high thermal inertia of the slab in order to perform the peak-shaving. The
peak-shaving consists in reducing the peak in the required cooling power (see Figure 3), so that it is possible
to cool the structures of the building during a period in which the occupants are absent (during night time, in
office premises). This way the energy consumption can be reduced and a lower night time electricity rate can
be used. At the same time a reduction in the size of heating/cooling system components (including the chiller)
is possible.
© ISO 2012 – All rights reserved 7
---------------------- Page: 19 ----------------------
SIST EN ISO 11855-4:2015
ISO 11855-4:2012(E)
Y
X
Key
X time, h
Y cooling power, W
1 heat gain
2 cooling power needed for conditioning the ventilation air
3 cooling power needed on the water side
4 reduction of the required peak power
Figure 3 — Example of peak-shaving effect
TABS may be used both with natural and mechanical ventilation (depending on weather conditions).
Mechanical ventilation with dehumidifying may be required depending on external climate and indoor humidity
production. In the example in Figure 3, the required peak cooling power needed for dehumidifying the air
during day time is sufficient to cool the slab during
...
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 4: Auslegung und Berechnung der dynamischen Wärme- und Kühlleistung für thermoaktive Bauteilsysteme (TABS) (ISO 11855-4:2012)Conception de l'environnement des bâtiments - Conception, construction et fonctionnement des systèmes de chauffage et de refroidissement par rayonnement - Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique et à la puissance frigorifique pour systèmes thermoactifs (TABS) (ISO 11855-4:2012)Building environment design - Design, dimensioning, installation and control of embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) (ISO 11855-4:2012)91.140.30VLVWHPLVentilation and air-conditioning91.140.10Sistemi centralnega ogrevanjaCentral heating systemsICS:Ta slovenski standard je istoveten z:FprEN ISO 11855-4kSIST FprEN ISO 11855-4:2015en,de01-maj-2015kSIST FprEN ISO 11855-4:2015SLOVENSKI
STANDARD
kSIST FprEN ISO 11855-4:2015
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
FINAL DRAFT
FprEN ISO 11855-4
January 2015 ICS 91.140.10; 91.140.30 Will supersede EN 15377-3:2007English Version
Building environment design - Design, dimensioning, installation and control of embedded radiant heating and cooling systems - Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) (ISO 11855-4:2012)
Conception de l'environnement des bâtiments - Conception, construction et fonctionnement des systèmes de chauffage et de refroidissement par rayonnement - Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique et à la puissance frigorifique pour systèmes thermoactifs (TABS) (ISO 11855-4:2012)
Umweltgerechte Gebäudeplanung - Planung, Auslegung, Installation und Steuerung flächenintegrierter Strahlheizungs- und -kühlsysteme - Teil 4: Auslegung und Berechnung der dynamischen Wärme- und Kühlleistung für thermoaktive Bauteilsysteme (TABS) (ISO 11855-4:2012) This draft European Standard is submitted to CEN members for unique acceptance procedure. It has been drawn up by the Technical Committee CEN/TC 228.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. FprEN ISO 11855-4:2015 EkSIST FprEN ISO 11855-4:2015
FprEN ISO 11855-4:2015 (E) 2 Contents Page Foreword .3 kSIST FprEN ISO 11855-4:2015
FprEN ISO 11855-4:2015 (E) 3 Foreword The text of ISO 11855-4:2012 has been prepared by Technical Committee ISO/TC 205 “Building environment design” of the International Organization for Standardization (ISO) and has been taken over as FprEN ISO 11855-4:2015 by Technical Committee CEN/TC 228 “Heating systems and water based cooling systems in buildings” the secretariat of which is held by DIN. This document is currently submitted to the Unique Acceptance Procedure. This document will supersede EN 15377-3:2007. This standard is applicable for design, construction and operation of radiant heating and cooling systems. The methods defined in part 2 are intended to determine the design heating or cooling capacity used for the design and evaluation of the performance of the system. For identifying product characteristics by testing and proving the thermal output of heating and cooling surfaces embedded in floors, ceilings and walls the standard series EN 1264 can be used. Endorsement notice The text of ISO 11855-4:2012 has been approved by CEN as FprEN ISO 11855-4:2015 without any modification. kSIST FprEN ISO 11855-4:2015
kSIST FprEN ISO 11855-4:2015
Reference numberISO 11855-4:2012(E)© ISO 2012
INTERNATIONAL STANDARD ISO11855-4First edition2012-08-01Building environment design — Design, dimensioning, installation and control of embedded radiant heating and cooling systems — Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) Conception de l'environnement des bâtiments — Conception, construction et fonctionnement des systèmes de chauffage et de refroidissement par rayonnement — Partie 4: Dimensionnement et calculs relatifs au chauffage adiabatique et à la puissance frigorifique pour systèmes thermoactifs (TABS)
kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E)
COPYRIGHT PROTECTED DOCUMENT
©
ISO 2012 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel.
+ 41 22 749 01 11 Fax
+ 41 22 749 09 47 E-mail
copyright@iso.org Web
www.iso.org Published in Switzerland
ii
© ISO 2012 – All rights reserved
kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) © ISO 2012 – All rights reserved
iii Contents Page Foreword . iv Introduction . v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions . 1 4 Symbols and abbreviations . 1 5 The concept of Thermally Active Surfaces (TAS) . 6 6 Calculation methods . 11 6.1 General . 11 6.2 Rough sizing method . 12 6.3 Simplified sizing by diagrams . 13 6.4 Simplified model based on finite difference method (FDM) . 19 6.4.1 Cooling system . 20 6.4.2 Hydraulic circuit and slab . 20 6.4.3 Room . 22 6.4.4 Limits of the method . 24 6.5 Dynamic building simulation programs . 25 7 Input for computer simulations of energy performance . 25 Annex A (informative)
Simplified diagrams . 26 Annex B (normative)
Calculation method . 31 B.1. Pipe level . 31 B.2. Thermal nodes composing the slab and room . 31 B.3. Calculations for the generic h-th hour . 35 B.4 Sizing of the system . 41 Annex C (informative)
Tutorial guide for assessing the model . 42 Annex D (informative)
Computer program . 44 Bibliography . 52
kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) iv
© ISO 2012 – All rights reserved 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. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. 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. ISO 11855-4 was prepared by Technical Committee ISO/TC 205, Building environment design. ISO 11855 consists of the following parts, under the general title Building environment design — Design, dimensioning, installation and control of embedded radiant heating and cooling systems: — Part 1: Definition, symbols, and comfort criteria — Part 2: Determination of the design and heating and cooling capacity — Part 3: Design and dimensioning — Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) — Part 5: Installation
— Part 6: Control Part 1 specifies the comfort criteria which should be considered in designing embedded radiant heating and cooling systems, since the main objective of the radiant heating and cooling system is to satisfy thermal comfort of the occupants. Part 2 provides steady-state calculation methods for determination of the heating and cooling capacity. Part 3 specifies design and dimensioning methods of radiant heating and cooling systems to ensure the heating and cooling capacity. Part 4 provides a dimensioning and calculation method to design Thermo Active Building Systems (TABS) for energy-saving purposes, since radiant heating and cooling systems can reduce energy consumption and heat source size by using renewable energy. Part 5 addresses the installation process for the system to operate as intended. Part 6 shows a proper control method of the radiant heating and cooling systems to ensure the maximum performance which was intended in the design stage when the system is actually being operated in a building. kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) © ISO 2012 – All rights reserved
v Introduction The radiant heating and cooling system consists of heat emitting/absorbing, heat supply, distribution, and control systems. The ISO 11855 series deals with the embedded surface heating and cooling system that directly controls heat exchange within the space. It does not include the system equipment itself, such as heat source, distribution system and controller. The ISO 11855 series addresses an embedded system that is integrated with the building structure. Therefore, the panel system with open air gap, which is not integrated with the building structure, is not covered by this series. The ISO 11855 series shall be applied to systems using not only water but also other fluids or electricity as a heating or cooling medium. The object of the ISO 11855 series is to provide criteria to effectively design embedded systems. To do this, it presents comfort criteria for the space served by embedded systems, heat output calculation, dimensioning, dynamic analysis, installation, operation, and control method of embedded systems. kSIST FprEN ISO 11855-4:2015
kSIST FprEN ISO 11855-4:2015
INTERNATIONAL STANDARD ISO 11855-4:2012(E) © ISO 2012 – All rights reserved 1 Building environment design — Design, dimensioning, installation and control of embedded radiant heating and cooling systems — Part 4: Dimensioning and calculation of the dynamic heating and cooling capacity of Thermo Active Building Systems (TABS) 1 Scope This part of ISO 11855 allows the calculation of peak cooling capacity of Thermo Active Building Systems (TABS), based on heat gains, such as solar gains, internal heat gains, and ventilation, and the calculation of the cooling power demand on the water side, to be used to size the cooling system, as regards the chiller size, fluid flow rate, etc. This part of ISO 11855 defines a detailed method aimed at the calculation of heating and cooling capacity in non-steady state conditions. The ISO 11855 series is applicable to water based embedded surface heating and cooling systems in residential, commercial and industrial buildings. The methods apply to systems integrated into the wall, floor or ceiling construction without any open air gaps. It does not apply to panel systems with open air gaps which are not integrated into the building structure. The ISO 11855 series also applies, as appropriate, to the use of fluids other than water as a heating or cooling medium. The ISO 11855 series is not applicable for testing of systems. The methods do not apply to heated or chilled ceiling panels or beams. 2 Normative references The following referenced documents are indispensable for the application 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 11855-1, Building environment design — Design, dimensioning, installation and control of embedded radiant heating and cooling systems — Part 1: Definition, symbols, and comfort criteria 3 Terms and definitions For the purposes of this document, the terms and definitions in ISO 11855-1 apply. 4 Symbols and abbreviations For the purposes of this part of ISO 11855, the symbols and abbreviations in Table 1 apply: kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) 2
© ISO 2012 – All rights reserved Table 1 — Symbols and abbreviations Symbol Unit Quantity FA m2 Area of the heating/cooling surface area WA m2 Total area of internal vertical walls (i.e. vertical walls, external façades excluded) C J/(m2áK) Specific thermal capacity of the thermal node under consideration WC J/(m2áK) Average specific thermal capacity of the internal walls jc J/(kgáK) Specific heat of the material constituting the j-th layer of the slab wc J/(kgáK) Specific heat of water ad m External diameter of the pipe EDay kWh/m2 Specific daily energy gains hrmf - Running mode (1 when the system is running; 0 when the system is switched off) in the h-th hour sf - Design safety factor v F-CF - View factor between the floor and the ceiling v F-EWF - View factor between the floor and the external walls v F-WF - View factor between the floor and the internal walls A-Ch W/(m2áK) Convective heat transfer coefficient between the air and the ceiling A-Fh W/(m2áK) Convective heat transfer coefficient between the air and the floor A-Wh W/(m2áK) Convective heat transfer coefficient between the air and the internal walls F-Ch W/(m2áK) Radiant heat transfer coefficient between the floor and the ceiling F-Wh W/(m2áK) Radiant heat transfer coefficient between the floor and the internal walls HA W/K Heat transfer coefficient between the thermal node under consideration and the air thermal node (“A”) HC W/K Heat transfer coefficient between the thermal node under consideration and the ceiling surface thermal node (“C”) HCircuit W/K Heat transfer coefficient between the thermal node under consideration and the circuit HCondDown W/K Heat transfer coefficient between the thermal node under consideration and the next one HCondUp W/K Heat transfer coefficient between the thermal node under consideration and the previous one HConv - Fraction of internal convective heat gains acting on the thermal node under consideration HF W/K Heat transfer coefficient between the thermal node under consideration and the floor surface thermal node (“F”) HInertia W/K Coefficient connected to the inertia contribution at the thermal node under consideration HIWS W/K Heat transfer coefficient between the thermal node under consideration and the internal wall surface thermal node (“IWS”) HRad - Fraction of total radiant heat gains impinging on the thermal node under consideration th W/(m2áK) Total heat transfer coefficient (convection + radiation) between surface and space J - Number of layers constituting the slab as a whole kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) © ISO 2012 – All rights reserved 3 Symbol Unit Quantity 1J - Number of layers constituting the upper part of the slab 2J - Number of layers constituting the lower part of the slab RL m Length of installed pipes H,spm kg/(m2ás) Specific water flow in the circuit, calculated on the area covered by the circuit jm - Number of partitions of the j-th layer of the slab n - Actual number of iteration in iterative calculations nh h Number of operation hours of the circuit nMax - Maximum number of iterations allowed in iterative calculations Max,hCircuitP W Maximum cooling power reserved to the circuit under consideration in the h-th hour MaxCircuit,SpecP W/m2 Maximum specific cooling power (per floor square metre) qi W/m2 Inward specific heat flow qu W/m2 Outward specific heat flow hCQ W Heat flow impinging on the ceiling surface (“C”) in the h-th hour hCircuitQ W Heat flow extracted by the circuit in the h-th hour hConvQ W Total convective heat gains in the h-th hour hFQ W Heat flow impinging on the floor surface (“F”) in the h-th hour hIntConvQ W Internal convective heat gains in the h-th hour hIntRadQ W Internal radiant heat gains in the h-th hour hIWSQ W Heat flow impinging on the internal wall surface (“IWS”) in the h-th hour hPrimAirQ W Primary air convective heat gains in the h-th hour hRadQ W Total radiant heat gains in the h-th hour hSunQ W Solar heat gains in the room in the h-th hour hTransmQ W Transmission heat gains in the h-th hour WQ W/m2 Average specific cooling power R (m2áK)/W Generic thermal resistance Add CR (m2áK)/W Additional thermal resistance covering the lower side of the slab Add FR (m2áK)/W Additional thermal resistance covering the upper side of the slab RCAC K/W Convection thermal resistance connecting the air thermal node (“A”) with the ceiling surface thermal node (“C”) RCAF K/W Convection thermal resistance connecting the air thermal node (“A”) with the floor surface thermal node (“F”) RCAW K/W Convection thermal resistance connecting the air thermal node (“A”) with the internal wall surface thermal node (“IWS”) kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) 4
© ISO 2012 – All rights reserved Symbol Unit Quantity Rint (m2áK)/W Internal thermal resistance of the slab conductive region RL,p (m2áK)/W Conduction thermal resistance connecting the p-th thermal node with the boundary of the (p+1)-th thermal node rR (m2áK)/W Pipe thickness thermal resistance RRFC K/W Radiation thermal resistance connecting the floor surface thermal node (“F”) with the ceiling surface thermal node (“C”) RRWC K/W Radiation thermal resistance connecting the internal wall surface thermal node (“IWS”) with the ceiling surface thermal node (“C”) RRWF K/W Radiation thermal resistance connecting the internal wall surface thermal node (“IWS”) with the floor surface thermal node (“F”) Rt (m2áK)/W Circuit total thermal resistance RU,p (m2áK)/W Conduction thermal resistance connecting the p-th thermal node with the boundary of the (p-1)-th thermal node WallsR (m2áK)/W Wall surface thermal resistance wR (m2áK)/W Water flow thermal resistance xR (m2áK)/W Pipe level thermal resistance zR (m2áK)/W Convection thermal resistance at the pipe inner side rs m Pipe wall thickness 1s m Thickness of the upper part of the slab 2s m Thickness of the lower part of the slab W m Pipe spacing j/ m Thickness of the j-th layer of the slab K Generic temperature difference MaxComfort K Maximum operative temperature drift allowed for comfort conditions t s Calculation time step hA °C Temperature of the air thermal node (“A”) in the h-th hour hC °C Temperature of the ceiling surface thermal node (“C”) in the h-th hour MaxComfort °C Maximum operative temperature allowed for comfort conditions Comfort,Ref °C Maximum operative temperature allowed for comfort conditions in the reference case hF °C Temperature of the floor surface thermal node (“F”) in the h-th hour hIW °C Temperature of the core of the internal walls thermal node (“IW”) in the h-th hour hIWS °C Temperature of the internal wall surface thermal node (“IWS”) in the h-th hour hMR °C Room mean radiant temperature in the h-th hour hOp °C Room operative temperature in the h-th hour kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) © ISO 2012 – All rights reserved 5 Symbol Unit Quantity hp °C Temperature of the p-th thermal node in the h-th hour hPL °C Temperature of the pipe level thermal node (“PL”) in the h-th hour AvSlab °C Daily average temperature of the conductive region of the slab hWater,In °C Water inlet actual temperature in the h-th hour Setp,hWater,In °C Water inlet set-point temperature in the h-th hour SetpWater,In,Ref °C Water inlet set-point temperature in the reference case hWater,Out °C Water outlet temperature in the h-th hour b W/(máK) Thermal conductivity of the material of the pipe embedded layer j W/(máK) Thermal conductivity of the material constituting the j-th layer of the slab r W/(máK) Thermal conductivity of the material constituting the pipe K Actual tolerance in iterative calculations Max K Maximum tolerance allowed in iterative calculations j kg/m3 Density of the material constituting the j-th layer of the slab various Slope of correlation curves
kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) 6
© ISO 2012 – All rights reserved 5 The concept of Thermally Active Surfaces (TAS) A Thermally Active Surface (TAS) is an embedded water based surface heating and cooling system, where the pipe is embedded in the central concrete core of a building construction (see Figure 1).
Key C concrete F floor P pipes R room RI reinforcement W window Figure 1 — Example of position of pipes in TAS The building constructions embedding the pipe are usually the horizontal ones. As a consequence, in the following sections, floors and ceilings are usually referred to as active surfaces. Looking at a typical structure of a TAS, heat is removed by a cooling system (for instance, a chiller), connected to pipes embedded in the slab. The system can be divided into the elements shown in Figure 2. kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) © ISO 2012 – All rights reserved 7
Key 1 heating/cooling equipment 2 hydraulic circuit 3 slab including core layer with pipes 4 possible additional resistances (floor covering or suspended ceiling) 5 room below and room above PL pipe level Figure 2 — Simple scheme of a TAS Thermally active surfaces exploit the high thermal inertia of the slab in order to perform the peak-shaving. The peak-shaving consists in reducing the peak in the required cooling power (see Figure 3), so that it is possible to cool the structures of the building during a period in which the occupants are absent (during night time, in office premises). This way the energy consumption can be reduced and a lower night time electricity rate can be used. At the same time a reduction in the size of heating/cooling system components (including the chiller) is possible. kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) 8
© ISO 2012 – All rights reserved YX Key X time, h Y cooling power, W 1 heat gain 2 cooling power needed for conditioning the ventilation air 3 cooling power needed on the water side 4 reduction of the required peak power Figure 3 — Example of peak-shaving effect TABS may be used both with natural and mechanical ventilation (depending on weather conditions). Mechanical ventilation with dehumidifying may be required depending on external climate and indoor humidity production. In the example in Figure 3, the required peak cooling power needed for dehumidifying the air during day time is sufficient to cool the slab during night time. As regards the design of TABS, the planner needs to know if the capacity at a given water temperature is sufficient to keep the room temperature within a given comfort range. Moreover, the planner needs also to know the heat flow on the water side to be able to dimension the heat distribution system and the chiller/boiler. This part of ISO 11855 provides methods for both purposes. When using TABS, the indoor temperature changes moderately during the day and the aim of a good TABS design is to maintain internal conditions within the range of comfort, i.e. –0,5 < PMV < 0,5, during the day, according to ISO 7730 (see Figure 4). kSIST FprEN ISO 11855-4:2015
ISO 11855-4:2012(E) © ISO 2012 – All rights reserved 9 YX Key X
time, h Y
temperature, °C PMV
Predicted Mean Vote air
air temperature c
ceiling temperature mr
mean radiant temperature f
floor temperature w exit
water return temperature Figure 4 — Example of temperature profiles and PMV values vs. time Some detailed building system calculation models have been developed to determine the heat exchanges under unsteady state conditions in a single room, the thermal and hygrometric balance of the room air, prediction of comfort conditions, check of condensation on surfaces, availability of control strategies and calculation of the incoming solar radiation. The use of such detailed calculation models is, however, limited due to the high amount of time needed for the simulations. The development of a more user friendly tool is required. Such a tool is provided in this part of ISO 11855, and allows the simulation of TAS. The diagrams in Figure 5 show an example of the relation between internal heat gains, water supply temperature, heat transfer on the room side, hours of operation and heat transfer on the water side. The diagrams refer to a concrete slab with raised floor (R = 0,45 (m2áK)/W) and an allowed room temperature range of 21°C to 26°C. The upper diagram shows on the Y-axis the maximum permissible total heat gain in space (internal heat gains plus solar gains) [W/m2], and on the X-axis the required water supply temperature. The lines in the diagram correspond to different operation periods (8 h, 12 h, 16 h, and 24 h) and different maximum amounts of energy supplied per day [Wh/(m2ád)]. The lower diagram shows the cooling power [W/m2] required on the water side (to dimension the chiller) for TAS as a function of supply water temperature and operation time. Further, the amount of energy rejected per day is indicated [Wh/(m2ád)]. The example shows that, for a m
...
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