CEN/TR 15316-6-9:2017

SLOVENSKI STANDARD
01-maj-2018
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Energy performance of buildings - Method for calculation of system energy requirements
and system efficiencies - Part 6-9: Explanation and justification of EN 15316-4-8, Module
M3-8-8
Heizungsanlagen und Wasserbasierte Kühlanlagen in Gebäuden - Verfahren zur
Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen - Teil 6-9:
Begleitender TR zur EN 15316-4-8 (Wärmeerzeugung von Warmluft- und
Strahlungsheizsystemen)
Performance énergétique des bâtiments - Méthode de calcul des besoins énergétiques
et des rendements des systèmes - Partie 6-9: Explication et justification de l’EN 15316-4-
8, Module M3-8-8
Ta slovenski standard je istoveten z: CEN/TR 15316-6-9:2017
ICS:
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 15316-6-9
TECHNICAL REPORT
RAPPORT TECHNIQUE
May 2017
TECHNISCHER BERICHT
ICS 27.160; 91.120.10; 91.140.10
English Version
Energy performance of buildings - Method for calculation
of system energy requirements and system efficiencies -
Part 6-9: Explanation and justification of EN 15316-4-8,
Module M3-8-8
Performance énergétique des bâtiments - Méthode de Heizungsanlagen und Wasserbasierte Kühlanlagen in
calcul des besoins énergétiques et des rendements des Gebäuden - Verfahren zur Berechnung der
systèmes - Partie 6-9: Explication et justification de Energieanforderungen und Nutzungsgrade der
l'EN 15316-4-8, Module M3-8-8 Anlagen - Teil 6-9: Begleitender TR zur EN 15316-4-8
(Wärmeerzeugung von Warmluft- und
Strahlungsheizsystemen)
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 15316-6-9:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 9
3 Terms and definitions . 9
4 Symbols and subscripts . 9
4.1 Symbols . 9
4.2 Subscripts . 10
5 Information on the methods . 10
5.1 Output of the method . 10
5.2 Alternative methods . 10
5.3 Connection with building needs and zoning . 11
5.4 Application data. 11
5.5 Using net and gross calorific values . 11
6 Single stage heaters . 12
6.1 Rationale . 12
6.1.1 General . 12
6.1.2 Losses calculation principle . 12
6.1.3 Auxiliary energy . 13
6.1.4 Expression of heat losses . 14
6.1.5 Recoverable, recovered and unrecoverable heat losses . 14
6.1.6 Input data . 14
6.1.7 Characterization of a heater . 15
6.1.8 Characterization of local heaters include into lot 20 of Ecodesign regulation . 15
6.1.9 Operating conditions characterization . 15
6.1.10 Energy balance diagram . 16
6.1.11 Assumptions . 18
6.2 Calculation intervals . 18
6.3 Input data . 18
6.3.1 Product data . 18
6.3.2 System design data . 21
6.3.3 Operating conditions . 21
6.3.4 Constants and physical data . 21
6.4 Calculation procedure . 22
6.4.1 Applicable timestep . 22
6.4.2 Time with burner ON and OFF . 22
6.4.3 Loss factors calculation . 22
6.4.4 Recovered auxiliary energy. 23
6.4.5 Energy calculation . 23
7 Multistage and modulating heaters . 24
7.1 Output data . 24
7.2 Calculation intervals . 24
7.3 Input data . 24
7.3.1 Product data . 24
7.3.2 System design data . 24
7.3.3 Operating conditions . 24
7.3.4 Constants and physical data . 24
7.4 Calculation procedure . 24
7.4.1 Applicable calculation interval . 24
7.4.2 Operating conditions calculation . 24
7.4.3 Time with burner ON and OFF . 24
7.4.4 Loss factors calculation . 24
7.4.5 Auxiliary energy at minimum power . 25
7.4.6 Energy calculation . 25
8 Stoves and local heaters . 25
8.1 General . 25
8.2 Stoves without connection to a water based system . 26
8.2.1 Output data . 26
8.2.2 Input data . 26
8.2.3 Special cases . 26
8.2.4 Data input for solid fuel local heaters included in Lot 20 of Ecodesign regulation . 26
8.3 Stoves and local heaters with a connection to a water based heating system . 26
9 Method selection . 27
10 Worked out examples . 27
11 Application range . 27
12 Regulation use . 27
13 Information on the accompanying spreadsheet . 27
14 Results of the validation tests . 27
15 Quality issues . 28
Annex A (informative) Calculation flowchart . 29
A.1 Single stage heater . 29
A.2 Multi-stage and modulating heaters . 30
Annex B (informative) Balance formulae and origin of iteration formulae . 31
B.1 General . 31
B.2 Energy balance for single stage heaters . 31
B.3 Multi-stage or modulating . 32
B.3.1 Expression of losses . 32
B.3.2 Multi-stage or modulating – on/off attempt . 34
B.3.3 Multi-stage or modulating – average power calculation . 35
Annex C (informative) Example: On-Off heater . 36
Bibliography . 44

European foreword
This document (CEN/TR 15316-6-9:2017) 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 [and/or CENELEC] 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
The set of EPB standards, technical reports and supporting tools:
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, 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, 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 52000-1:2017.
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
(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 [2]):
- 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 [4] that laid the
foundation for the preparation of the set of EPB standards.
1 Scope
This Technical Report refers to EN 15316-4-8:2017, module M3-8.8.
It contains information to support the correct understanding, use and national adaptation of
EN 15316-4-8:2017.
This Technical Report does not contain any normative provision.
The scope of EN 15316-4-8:2017 includes three categories of products:
• air heating systems means a system with one or more warm air generators for heating purpose.
The hot air may be diffused in the installation space from the generator or distributed via a
ductwork.
• overhead radiant heating systems, means systems using gas and designed to provide heat into the
installation room. Radiation may be generated directly by the flame (overhead radiant luminous
heaters) or by circulation of flue gas in a ductwork installed near the ceiling (overhead radiant tube
heaters).
• stoves and local heaters means local devices that provide heat by transferring the heat generated
by combustion into the surrounding environment.
The typical devices are shown in Figures 1 to 4.

Figure 1 — Warm air generator for an air heating system
Figure 2 — Overhead radiant luminous heater

Figure 3 — Overhead radiant tube heater

a) b)
Figure 4 — Examples of local space heater: pellet stove and inset
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 15316-1, Energy performance of buildings — Method for calculation of system energy requirements
and system efficiencies — Part 1: General and Energy performance expression, Module M3-1, M3-4, M3-9,
M8-1, M8-4
EN 15316-4-8:2017, Energy performance of buildings — Method for calculation of system energy
requirements and system efficiencies — Part 4-8: Space heating generation systems, air heating and
overhead radiant heating systems, including stoves (local), Module M3-8-8
EN ISO 7345:1995, Thermal insulation — Physical quantities and definitions (ISO 7345:1987)
EN ISO 52000-1:2017, Energy performance of buildings — Overarching EPB assessment — Part 1:
General framework and procedures (ISO 52000-1:2017)
NOTE References in the text of the standard are given as module codes that are detailed in the annex. This
enables flexible references (e.g. to national documents where necessary for local application) and use outside the
CEN environment.
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 and EN 15316-4-8:2017 apply.
NOTE 1 No new definition is given in this Technical Report.
NOTE 2 During public enquiry, it was commented that the term “stove” is not appropriate. The correct term,
which is used in the product standard is “local heaters”, meaning a heater which is not attached to any distribution
system. The term “stove” survived in the title, as a synonym of “local heater” because the title of a standard cannot
be changed during the drafting process.
4 Symbols and subscripts
4.1 Symbols
For the purposes of this document some special symbols are defined in EN 15316-4-8:2017:
— α is used for losses factors. They are expressed as a percentage, so the usual range is 0 to 100. Some
negative values or values beyond 100 are expected when dealing with condensing heaters.
— β is used for loaf factors. They are expressed in per unit, so the usual range is 0 to 1. Typically β is a
value that changes at each calculation interval depending on load.
— ∇ϑ has been used for the vertical temperature gradient.
NOTE: ∇ϑ is not a temperature difference but a temperature gradient, e.g. a temperature difference per unit
length expressed in °C/m.
4.2 Subscripts
The subscript “lrh” (“Local Radiant Heaters”) has been used to identify all symbols that are exclusive to
this standard.
5 Information on the methods
5.1 Output of the method
The output of this method is the same as any heat generation sub-system and the same time-step of the
output. If necessary, it is possible to combine different calculation intervals for the input and the output.
This is specified in EN 15316-4-8:2017, 6.2.
No significant dynamic effect is taken into account. There is no difference in the calculation for any
calculation interval from hourly to seasonal.
A more detailed analysis could be required in future for independent heaters with a high heat capacity
(slow release heat stoves).
The heater seasonal efficiency or expenditure factor could be used as a legal requirement. It should be
clear if this indicator has to include or not the effect of auxiliaries and, if so, which weighting factors
shall be used. More information about extracting specific indicators is available in EN 15316-1.
The calculated performance of the heater takes into account:
— type and characteristics of the radiant heater;
— heater settings;
— type of the heater control;
— location of the heater (e.g. indoor/outdoor);
— operating conditions;
— heat requirement.
5.2 Alternative methods
A separate method is given for:
— on-off heaters (EN 15316-4-8:2017, Clause 6);
— multi-stage and modulating heaters (EN 15316-4-8:2017, Clause 7).
No distinction is made between multi-stage and modulating heaters. A linear behaviour is assumed
between minimum and maximum power continuous operation.
An on/off heater is characterized by 2 possible states:
1) burner off (tON);
2) burner on at maximum power (tOFF).
and the calculation procedure determines the duration of t (or the load factor β )
lrh;ON lrh;cmb
A multistage or modulating generator is characterized by 3 states:
3) burner off;
4) burner on at minimum power;
5) burner on at maximum power.
It is assumed that only two situations are possible:
6) the burner is operating intermittently as a single stage burner at minimum power;
7) the burner is operating at a constant average power between minimum and maximum power.
A separate complementary procedure is given for heaters that include a heat exchanger to provide heat
to a water based heating system (8.3).
5.3 Connection with building needs and zoning
Since there is no distribution system, a radiant heater or a stove may contribute only to the heating of
the spaces where it is installed.
It is relevant to limit the possibility of the heater to supply heat to the building especially in the case of
wood stoves and other heaters running with biomass to avoid unreal advantages.
This implies that thermal zones are set up so to isolate the part of the building that might be heated by a
local heater. As an alternative, the potential contribution of the local heater or stove to the thermal zone
should be limited to a quota given by the ratio between the area or volume heated and the thermal zone
area or volume.
5.4 Application data
No application data are specified in the normative part of EN 15316-4-8:2017.
EN 15316-4-8:2017, Annex A provides a template to specify the required application data.
EN 15316-4-8:2017, Annex B includes informative default application data for immediate use of the
standard. Other application data can be specified by national standards and regulations, depending on
the purpose of the calculation.
See also EN 15316-4-8:2017, A.1 and B.1.
5.5 Using net and gross calorific values
The method described in EN 15316-4-8 is based on the net calorific value, which is the most common
reference in the legislation, also for safety issues.
If the input data are given with reference to gross calorific values it shall be converted.
If the output data are desired with reference to gross calorific values it shall be converted.
Net and gross calorific values are given by reference to EN ISO 52000-1:2017. A different (e.g. national)
reference can be specified via a specific table complying with EN 15316-4-8:2017, Table A.1.
6 Single stage heaters
6.1 Rationale
6.1.1 General
The calculation method for air and radiant heaters and stoves is based on the analysis and estimation of
losses.
The main input data are the tested efficiencies at full and minimum power and losses factors.
Measured efficiencies are converted into losses factors.
Operating conditions are taken into account by correcting the losses factors according to actual
operating conditions as compared to test conditions. Default correlations and data are used for the
correction.
A calculation flowchart is given in Annex A of this technical report.
6.1.2 Losses calculation principle
The operation time of the generator t is the total time when the generator is available to supply
lrh;gen
heat as demanded by the temperature control. It is a specified fraction of the calculation interval (tci),
depending on the timing control of the generation.
— For a monthly calculation interval, the operation time depends on the operation schedule
— For an hourly calculation interval, the operation time is usually the entire hour or zero if the hour is
part of a non-heating period.
The operation time of the generator t is divided in two parts:
lrh;gen
— t time with the burner on (only fuel valve open, any pre- and post-ventilation are not
lrh;ON
considered in this method)
— t time with the burner off
lrh;OFF
Heat losses are taken into account separately for t and t .
lrh;ON lrh;OFF
t and t are calculated in this module depending on the required heat output and the type, size
lrh;ON lrh;OFF
and losses characteristics of the heater or stove. See 6.1.2 for more details on time intervals.
Where applicable, depending on the heater type, the following heat losses are taken into account during
burner on operation:
— heat losses of flue gas with burner on: Q ;
lrh;ch;on
— heat losses due to ventilation finalized to evacuate flue gases Q (only for type A appliances
lrh;vent;on
that discharge the flue gas directly in the heated space)
— heat losses through the generator envelope: Q
lrh;env
Where applicable, depending on the heater type, the following heat losses are taken into account during
burner off time:
— heat of air flow to the chimney Q ;
lrh;ch:OFF
— heat losses by a permanent pilot burner operation Q
lrh;plt
— heat losses due to ventilation finalized to evacuate flue gases Q if there is no interlock to stop
lrh;vent;on
ventilation devices during burner off time.
6.1.3 Auxiliary energy
Auxiliary energy is the energy, other than fuel, required for operation of the burner, the burner fan and
any other heater component.
Auxiliary energy is considered separately for devices and components that operate only when the
burner is on (e.g. operating during t ) and other components and devices (i.e. system blowers or
lrh;ON
recirculation blowers) that are operating during the entire operation time t :
lrh;gen
— W is the auxiliary energy required by components and devices directly related to the
lrh;br
combustion function (typically. burner fan, burner control and fuel valve, main blower)
NOTE 1 These components and devices are running only when the burner is on, i.e. during tlrh;ON.
— W is the auxiliary energy required by additional components and devices that are running both
lrh;blw
during t and t Usually they are located after the combustion chamber following the energy
ON OFF.
path (f.e. recirculation blower of large tube heaters)
NOTE 2 These components and devices are running during the entire operation period of the heat generator,
i.e. during tlrh;gen = tlrh;ON + tlrh;OFF.
For easy connection with product data specification, stand-by auxiliary power can be specified as well.
Stand-by power and energy is related to the time when the burner is off,
For modulating devices, the auxiliary power can be differentiated between full load and minimum
modulation operation.
Auxiliary energy may partially be recovered as heat for space heating or for the generation sub-system.
Examples of recoverable auxiliary energy:
— part of the electrical energy for the burner fan, valve, control
Example of non-recoverable auxiliary energy:
— electrical energy for electric panel auxiliary circuits, if the generator is installed outside the heated
space.
The factors k and k express the fractions of the auxiliary energy recovered to the heating
lrh;aux;rh lrh;aux;rh
medium. Therefore:
— Q = k • W is the auxiliary energy recovered from components and devices directly
lrh;br lrh;aux;rh;br lrh;br
related to the combustion function;
— Q = k • W is the auxiliary energy recovered from components and devices that
lrh;blw lrh;aux;rh;blw lrh;blw
are operating continuously.
— Q = • W is the auxiliary energy recovered from components and devices that are
lrh;sby klrh;aux;rh;sby lrh;sby
operating during stand-by.
Auxiliary energy transformed into heat and emitted to the heated space may be considered separately
and is added to the recoverable heat losses.
6.1.4 Expression of heat losses
Heat losses are expressed as a percentage (α , α … α ) of nominal thermal input Φ .
lrh;ch;ON lrh;plt lrh;env lrh;cmb
Heat losses are expressed at test conditions and then corrected at actual operating conditions, where
relevant.
6.1.5 Recoverable, recovered and unrecoverable heat losses
Not all of the calculated heat losses are lost. Some of the total losses are recoverable and then part of the
recoverable losses are actually recovered.
— The losses recovered by the heater itself are directly taken into account in the heater performance
(e.g. combustion air preheating by flue gas losses).
— The recovery of losses to the heated space depends on the location of the heater and on the
loss/gains balance of the heated space. These recoverable losses are made available for further
calculation in other modules.
Example of recoverable heat losses:
— heat losses through the envelope of a generator installed within the heated space.
Example of non-recoverable heat losses:
— heat losses through the envelope of a generator installed outside the heated space;
— heat losses through the chimney.
6.1.6 Input data
Input data are organized in the following categories:
— Product description data (qualitative)
— Product technical data (quantitative)
— Process design data
Control type data
Operating conditions data
— Constants and physical data
Product data are properties of the individual product, which can be typically found in a product
catalogue.
Product data are divided in two categories:
— product description data (qualitative, standardized selection properties), given by an identifier;
— product technical data (quantitative, standardized technical properties), given by values.
6.1.7 Characterization of a heater
A basic single stage heater is characterized by the following values:
— Φ thermal input of the generator, which is the reference power for losses
lrh;cmb
factors α , α … α ;
lrh;ch;ON lrh;plt lrh;env
— α , α … α heat loss factors at test conditions (according to the type of heater);
lrh;ch;ON lrh;plt lrh;env
— Plrh;br electrical power of auxiliary appliances directly related to the burner;
— k recovery factor of P ;
lrh;aux;rh;br lrh;br
— P electrical power of additional auxiliary appliances ;
lrh;blw
— k recovery factor of P ;
lrh;aux;rh;blw lrh;blw
For multistage or modulating heaters, the following additional data are required:
— Φ minimum thermal input of the generator ;
lrh;cmb;min
— α heat loss factor α at minimum thermal input Φ n;
lrh;ch;ON,min lrh;ch;ON lrh;cmb;m
i
— P electrical power of auxiliary appliances (directly related to the
lrh;br,min
combustion function) at minimum thermal input Φ .
lrh;cmb;min
For condensing heaters, the following additional data are required:
— η combustion efficiency on basis fuel net calorific value
lrh;cmb
For condensing multistage or modulating heaters, the following additional data are required:
— η combustion efficiency on gas net (lower) calorific value at minimum
cmb;min
thermal input
6.1.8 Characterization of local heaters include into lot 20 of Ecodesign regulation
These heaters are characterized by the data declared in the product data sheet. EN 15316-4-8:2017,
Annex C shows the relation between Ecodesign data and the required input.
Annex C has been kept informative because the regulation is still a draft.
6.1.9 Operating conditions characterization
Actual operation conditions are characterized by the following values:
a) QH,gen,out heat output to the heat distribution or heat emission sub-system(s);
generator installation room temperature, that can be:
b) ϑinst
1) the internal temperature if the appliance is located within the heated space,
2) the external temperature if the appliance is located outside;
c) k reduction factor taking into account recovery of heat losses through the generator
lrh;env;rvd
envelope, depending on location of the generator;
d) β the load factor, that is a calculation result.
lrh;cmb
NOTE All powers and the load factor β are referred to heater input (thermal input).
lrh;cmb
6.1.10 Energy balance diagram
Figure 5 shows the energy balance for the generation sub-system
Key
LRH Heater energy balance boundary
HF Heating fluid balance boundary
QH,gen,out Heater heat output (input to distribution subsystem(s))
EH,gen,in Heater fuel input (energyware)
W Heater total auxiliary energy
H,gen,aux
QH,gen,aux,rvd Heater recovered auxiliary energy
QH,gen,ls Heater total thermal heat losses
Q Heater recoverable heat
H,gen,ls,rbl
Q Heater recoverable thermal losses
H,gen,rbl,th
QH,gen,rbl,aux Heater recoverable auxiliary energy
QH,gen,nrbl,th Heater non recoverable thermal losses
Q Heater non recoverable auxiliary energy
H,gen,nrbl,aux
NOTE Figures shown are sample percentages
Figure 5 — Heater energy inputs, outputs and energy balance
6.1.11 Assumptions
In the previous edition of EN 15316-4-8, the power of auxiliaries was assumed to be constant. No
reduction of electric power was taken into account when a heater modulates between or switches from
maximum to minimum thermal input.
Now this feature has been introduced since it is a very common feature to have variable speed drive on
blowers and for new devices complying with Ecodesign regulations the auxiliary power is declared
separately at maximum power, minimum power and stand-by.
It is assumed that the induced ventilation flow rate is not modulated according to heater power, e.g. it is
only on or off. The only possibility taken into account is an interlock that shuts off the ventilation when
the heater burner is off.
6.2 Calculation intervals
The objective of the calculation is to determine the energy input of the heating generation sub-system
for the entire calculation period (usually one year). This may be done in one of the following two
different ways:
— by using average (usually yearly) data for the entire calculation period;
— by dividing the calculation period into a number of calculation steps (e.g. months, weeks, bins,
operation modes as defined in EN ISO 52000-1:2017) and perform the calculations for each step
using step-dependent values and adding up the results for all the steps over the calculation period.
Generation efficiency is strongly dependent on the load factor and this relationship is not linear. To
achieve a good precision, the calculation steps should not be longer than 1 month.
No significant heat accumulation effect is thought to be significant for these generators on the time scale
of 1 h. The method is equally valid for any calculation interval, from hourly to seasonal. An exception
might be stoves.
6.3 Input data
6.3.1 Product data
6.3.1.1 Product description data
Product description data are qualitative data that identifies the type of heater.
These identifiers are used to select the relevant calculation method (single-stage versus modulating,
condensing or non-condensing) .
The first list (heater type) should contain all the heater types that are referred in the default data tables
in EN 15316-4-8:2017, Annex B. The identifiers can be specified nationally according to the template
given in EN 15316-4-8:2017, Annex A. It is up to the compiler of the application data to keep
consistencies with the identifiers list.
Some identifiers that control the calculation route should be connected to the main identifier to avoid
mistakes.
EXAMPLE The LRH_COND (condensing / non condensing), LRH_PILOT (presence/absence of a permanent
pilot flame) and LRH_VENT (need of a ventilation flow rate in the installation room to evacuate the flue gases) can
be easily connected to the main LHR_TYPE identifier.
6.3.1.2 Product technical data
6.3.1.2.1 General
EN 15316-4-8:2017, Table 5 is a list of the required product technical data.
— The “catalogue unit” are the practical unit that may be available in the product testing
— The “computed units” are the standardized units within the whole EPB standards package.
— The “validity interval” can be used for a coherence test and to check for invalid input
— “Ref” is the clause where the data are described in detail
— “Varying” specifies whether the value may vary (or not) according to the calculation step.
6.3.1.2.2 Full load thermal input Фlrh,comb,Pn
For air heaters there is no practical possibility to have reliable measurements of the heat output. The
only relevant data which is controlled and adjusted on the heater is the thermal input (power input).
Therefore input power (thermal input) is the reference power for this type of heat generators.
6.3.1.2.3 Heat losses to the flue with burner on αlrh,ch,on
These losses can be measured through a flue gas analysis.
For condensing appliances, this value shall not include any contribution from latent heat recovery.
6.3.1.2.4 Correction factor flrh,corr,ch,on for heat losses to the flue with burner on
This correction factor is linked to the change in to the temperature difference.
A typical value is 20°C/%. This correction factor shall not take into account latent heat recovery
(condensation).
6.3.1.2.5 Test temperature ϑlrh,air,test,on for heat losses to the flue with burner on
The typical value is 20 °C.
6.3.1.2.6 Load factor exponent nlrh,ch,on
This factor corrects losses through the flue at burner on. It takes into account the fact that at start up,
the boiler surfaces are colder and the efficiency higher. This is relevant only if there is a significant mass
of metal of the heat exchanger. No such effect is expected with free flames and radiant heaters.
Setting this factor to 0 cancels this correction.
The graph below shows the influence on losses of this correction factor according to the load factor.
Figure 6 — Influence of exponent n on the correction of loss factors
6.3.1.2.7 Auxiliary power of equipment related to the burner Φlrh,aux,br
This is the auxiliary power of devices and components that operate only when the burner is on.
Examples of such devices are:
— the combustion air blower that stops when the flame is off
— the fuel valve.
6.3.1.2.8 Auxiliary power of equipme
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