CEN/TR 12831-2:2017

SLOVENSKI STANDARD
01-december-2016
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Energy performance of buildings - Method for calculation of the design heat load - Part 2:
Explanation and justification of EN 12831-1, Module M3-3
Gesamtenergieeffizienz von Gebäuden - Methode zur Berechnung der Norm-Heizlast -
Teil 2: Begleitender TR zur EN 12831-1, Modul M3
Performance énergétique des bâtiments - Méthode de calcul de la charge thermique
nominale - Partie 2 : Explication et justification de l’EN 12831-1, Module M3-3
Ta slovenski standard je istoveten z: CEN/TR 12831-2:2017
ICS:
91.120.10 Toplotna izolacija stavb Thermal insulation of
buildings
91.140.10 Sistemi centralnega Central heating systems
ogrevanja
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 12831-2
TECHNICAL REPORT
RAPPORT TECHNIQUE
April 2017
TECHNISCHER BERICHT
ICS 91.120.10; 91.140.10
English Version
Energy performance of buildings - Method for calculation
of the design heat load - Part 2: Explanation and
justification of EN 12831-1, Module M3-3
Performance énergétique des bâtiments - Méthode de Gesamtenergieeffizienz von Gebäuden - Methode zur
calcul de la charge thermique nominale - Partie 2 : Berechnung der Norm-Heizlast - Teil 2: Begleitender
Explication et justification de l'EN 12831-1, Module TR zur EN 12831-1, Modul M3
M3-3
This Technical Report was approved by CEN on 27 February 2017. It has been drawn up by the Technical Committee CEN/TC
228.
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, Serbia, 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
© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 12831-2:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols and abbreviations . 5
4.1 Symbols . 5
4.2 Subscripts . 5
5 Information on the methods . 5
6 Method description . 6
6.1 Standard method . 6
6.1.1 Rationale, case of application . 6
6.1.2 Assumptions . 6
6.1.3 Data input . 7
6.2 Simplified method for the calculation of the design heat load of a heated space . 19
6.2.1 Rationale, case of application . 19
6.2.2 Assumptions . 19
6.2.3 Data input . 19
6.3 Simplified method for the calculation of the building design heat load . 19
6.3.1 Rationale, case of application . 19
6.3.2 Assumptions . 20
6.3.3 Data input . 20
7 Method selection . 20
8 Exemplary heat load calculation (standard method) . 20
8.1 Description . 20
8.2 Calculation details . 22
Annex A (informative) Calculation flowchart . 28
A.1 General . 28
A.2 Standard method . 28
A.3 Simplified method for the calculation of the design heat load of a heated space . 29
A.4 Simplified method for the calculation of the building design heat load . 29
Bibliography . 30

European foreword
This document (CEN/TR 12831-2:2017) has been prepared by Technical Committee CEN/TC 228
“Heating systems and water based cooling systems in buildings”, the secretariat of which is held by DIN.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
Introduction
In order to facilitate the necessary overall consistency and coherence, in terminology, approach,
input/output relations and formats, for the whole set of EPB-standards, the following documents and
tools are available:
a) a document with basic principles to be followed in drafting EPB-standards: CEN/TS 16628:2014,
Energy Performance of Buildings - Basic Principles for the set of EPB standards [1];
b) a document with detailed technical rules to be followed in drafting EPB-standards;
CEN/TS 16629:2014, Energy Performance of Buildings - Detailed Technical Rules for the set of
EPB-standards [2];
c) the detailed technical rules are the basis for the following tools:
1) a common template for each EPB-standard, including specific drafting instructions for the
relevant clauses;
2) a common template for each technical report that accompanies an EPB standard or a cluster of
EPB standards, including specific drafting instructions for the relevant clauses;
3) a common template for the spreadsheet that accompanies each EPB standard, to demonstrate
the correctness of the EPB calculation procedures.
Each EPB-standards follows the basic principles and the detailed technical rules and relates to the
overarching EPB-standard, EN ISO 52000-1 [3].
One of the main purposes of the revision of the EPB-standards is to enable that laws and regulations
directly refer to the EPB-standards and make compliance with them compulsory. This requires that the
set of EPB-standards consists of a systematic, clear, comprehensive and unambiguous set of energy
performance procedures. The number of options provided is kept as low as possible, taking into
account national and regional differences in climate, culture and building tradition, policy and legal
frameworks (subsidiarity principle). For each option, an informative default option is provided
(EN 12831-1:2017, Annex B).
Rationale behind the EPB technical reports
There is a risk that the purpose and limitations of the EPB standards will be misunderstood, unless the
background and context to their contents – and the thinking behind them – is explained in some detail
to readers of the standards. Consequently, various types of informative contents are recorded and made
available for users to properly understand, apply and nationally or regionally implement the EPB
standards.
If this explanation would have been attempted in the standards themselves, the result is likely to be
confusing and cumbersome, especially if the standards are implemented or referenced in national or
regional building codes.
Therefore, each EPB standard is accompanied by an informative technical report, like this one, where all
informative content is collected, to ensure a clear separation between normative and informative
contents (see CEN/TS 16629 [1]):
— to avoid flooding and confusing the actual normative part with informative content;
— to reduce the page count of the actual standard; and
— to facilitate understanding of the set of EPB standards.
This was also one of the main recommendations from the European CENSE project [2] that laid the
foundation for the preparation of the set of EPB standards.
1 Scope
This Technical Report refers to standard EN 12831, module M3-3 (EN 12831-1).
It contains information to support the correct understanding, use and national adaptation of standard
EN 12831-1.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 12831-1:2017, Energy performance of buildings - Method for calculation of the design heat load - Part
1: Space heating load, Module M3-3
EN ISO 6946, Building components and building elements - Thermal resistance and thermal transmittance
- Calculation method (ISO 6946)
EN ISO 7345:1995, Thermal insulation - Physical quantities and definitions (ISO 7345:1987)
EN ISO 10077-1, Thermal performance of windows, doors and shutters - Calculation of thermal
transmittance - Part 1: General (ISO 10077-1)
EN ISO 52000-1:2017, Energy performance of buildings - Overarching EPB assessment - Part 1: General
framework and procedures (ISO 52000-1:2017)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN ISO 7345:1995,
EN ISO 52000-1:2017, EN 12831-1:2017 apply.
4 Symbols and abbreviations
4.1 Symbols
For the purposes of this Technical Report, the symbols given in EN ISO 52000-1:2017 and
EN 12831-1:2017 apply.
4.2 Subscripts
For the purposes of this Technical Report, subscripts given in EN ISO 52000-1:2017 and
EN 12831-1:2017 apply
5 Information on the methods
EN 12831-1 describes a method to calculate the design heat load of
— heated spaces (usually rooms);
— building entities (apartments etc.) or whole buildings containing heated spaces.
The design heat load is required in the sizing of several components of a heating systems, such as
— heat emission components (e.g. radiators);
— heat distribution components (tubing etc.); and
— heat generators (boilers etc.).
EN 12831-1 contains several methods for this purpose,
— a standard method that describes a versatile approach to calculate the design heat load of
— heated spaces / single rooms;
— building entities; and
— a whole building;
— a simplified method for the calculation of the design heat load of a building; and
— a simplified method for the calculation of the design heat load of heated spaces.
6 Method description
6.1 Standard method
6.1.1 Rationale, case of application
The standard method is a detailed approach for the calculation of the design heat load. The method is
based on design criteria, such as internal and external design temperatures, and detailed information
about the building or the heated spaces that the heat load shall be determined for. While the approach
itself is versatile in that it can be used for new (to-be-built) and existing or old buildings either way, it is
usually easier to apply to new ones
...