CEN/TR 15316-6-8:2017

SLOVENSKI STANDARD
01-maj-2018
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Energy performance of buildings - Method for calculation of system energy requirements
and system efficiencies - Part 6-8: Explanation and justification of EN 15316-4-5 (District
heating and cooling), Module M3-8-5, M4-8-5, M8-8-5, M11-8-5
Heizungsanlagen und Wasserbasierte Kühlanlagen in Gebäuden - Verfahren zur
Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen - Teil 6-8:
Begleitende TR zur EN 15316-4-5 (Fernwärme und Fernkälte)
Performance énergétique des bâtiments - Méthode de calcul des besoins énergétiques
et des rendements des systèmes - Partie 6-8 : Explication et justification de l’EN 15316-4
-5 (Chauffage et refroidissement urbains), Module M3-8-5, M4-8-5, M8-8-5, M11-8-5
Ta slovenski standard je istoveten z: CEN/TR 15316-6-8:2017
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 15316-6-8
TECHNICAL REPORT
RAPPORT TECHNIQUE
April 2017
TECHNISCHER BERICHT
ICS 91.120.10; 91.140.10; 91.140.30
English Version
Energy performance of buildings - Method for calculation
of system energy requirements and system efficiencies -
Part 6-8: Explanation and justification of EN 15316-4-5
(District heating and cooling), Module M3-8-5, M4-8-5,
M8-8-5, M11-8-5
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 6-8 : Explication et justification de Energieanforderungen und Nutzungsgrade der
l'EN 15316-4-5 (Chauffage et refroidissement urbains), Anlagen - Teil 6-8: Begleitende TR zur EN 15316-4-5
Module M3-8-5, M4-8-5, M8-8-5, M11-8-5 (Fernwärme und Fernkälte)

This Technical Report was approved by CEN on 3 March 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 15316-6-8:2017 E
worldwide for CEN national Members.

Contents Page
Contents
European foreword . 3
Introduction . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols, subscripts and abbreviations. 6
5 Indicators . 7
5.1 Output data . 7
5.2 Input data and calculation time step . 7
5.3 System boundaries . 8
6 Calculation methods for energy performance indicators . 9
6.1 Simplified approach . 9
6.2 Detailed calculation rules . 12
7 Setting default values. 20
7.1 Single-output systems . 20
7.2 Multi-output systems . 21
7.3 Conventions for missing input data and cascading multi-output systems . 23
7.4 Distribution networks . 24
8 Calculation of energy source indicators . 24
9 Report . 24
Annex A (informative) Default values . 25
Annex B (informative) Calculation examples. 27
B.1 Calculation example for a single-output district heating system (see 6.1) . 27
B.2 Calculation example for a multi-output district heating system (see 6.1) . 29
B.3 Calculation example for a district electricity system (see 6.1) . 30
B.4 Example for determining the electricity-related energy flows of the cogeneration
mode (see 6.2.2.1.3) . 32
B.5 Example for calculating CHP units with different allocation methods (see 6.2.2.1.5) . 34
B.6 Example for calculating RER and WHR. 37
B.7 Calculation example for a district cooling system. 39
Annex C (informative) Report example . 43
Bibliography . 44

European foreword
This document (CEN/TR 15316-6-8:2017) 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.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
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.
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 16628:2014, 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 52000-1:2017 [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
(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 [5] that laid the
foundation for the preparation of the set of EPB standards.
1 Scope
This Technical Report refers to standard EN 15316-4-5:2017.
It contains information to support the correct understanding, use and national adaptation of
EN 15316-4-5:2017
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 15316-4-5:2017, Energy performance of buildings - Method for calculation of system energy
requirements and system efficiencies - Part 4-5: District heating and cooling, Module M3-8-5, M4-8-5, M8-
8-5, M11-8-5
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 52000-1:2017 and
EN 15316-4-5:2017 apply.
4 Symbols, subscripts and abbreviations
For the purposes of this document, the symbols, subscripts and abbreviations given in
EN ISO 52000-1:2017 and EN 15316-4-5:2017 and the specific subscripts and abbreviations listed in
Table 1 and Table 2 apply.
Table 1 — Specific Subscripts
Subscript Term Subscript Term
abs absorption chiller ac ambient cooling
carnot carnot cch compression chiller
coal coal gf gaseous fuel
hn heating network infra infrastructure embedded
lf liquid fuel ncv net calorific value
return return sewage sewage sludge
supply supply upstr upstream chain
wte waste-to-energy
Table 2 — Abbreviations
Abbreviation Term
GCV gross calorific value
MIG multi-input generation unit
NCV net calorific value
WTE waste to energy
5 Indicators
5.1 Output data
The outcome of the calculation procedure is indicators that characterize a district energy system. The
indicators are subdivided into two groups. Energy performance indicators reflect efficiency aspects as
well as the source of the energy carrier. Energy source indicators don’t reflect the efficiency aspects of
the system but characterize the origin of the energy carrier.
In 2012/27/EU Article 2 No. (41) efficiency and energy source are defined differently: “Efficient district
heating and cooling’ means a district heating or cooling system using at least 50 % renewable energy, 50
% waste heat, 75 % cogenerated heat or 50 % of a combination of such energy and heat”.
However EN 15316-4-5 does not set any efficiency requirements but provides the calculation
procedures that facilitate compliance with requirements set by regulations like 2012/27/EU. RER, WHR
and CHR can directly be used for this purpose.
5.2 Input data and calculation time step
The vast majority of systems already exist so they should be assessed on the basis of measured energy
data. Due to the many factors that can affect district energy systems, the indicators can fluctuate over
time. For the purpose of building regulation a fluctuating energy indicator causes unwanted effects like
unequal treatment of customers connected to the same system. This can be limited by basing the
calculation on a broad range of data. Thus existing schemes shall be calculated using the energy data
from the last three years. If the system set-up or the fuel input mix has been changed within the last
three years the calculation may be based on the energy data from a single year.
Large systems supplying hundreds or even thousands of customers usually don’t have the possibility to
determine all input data on a monthly basis. Most energy indicators will therefore be valid for the whole
year.
In some special cases seasonal or monthly input data are required and available, e.g. in a trigeneration
system where cooling is supplied by an absorption chiller that is supplied by a cogeneration unit. On an
annual data basis it would not be possible to divide the power bonus into a heating-related part and a
cooling related part. Seasonal or monthly input data facilitate the determination of an accurate cooling
performance indicator and a heating performance indicator. Another example is a small new system
where even the delivered energy is calculated on a monthly basis.
In the determination of the final operating condition, the design conditions and manufacturing data the
following developments may be taken into account: heat demand changes, changes in numbers of
consumers, adaptations in generators and/or energy carriers.
5.3 System boundaries
If it is not possible or useful to calculate connected plants and networks together, they may be broken
down into subsystems. This results in some subsystems which consume energy and others that supply
energy. The energy from a supplier subsystem shall be assessed with its own energy indicators. For the
consumer subsystem this is an external energy supply which is taken into account as an energy input
with its specific energy indicators. According to EN 15316-4-5:2017, Table B.7 the subdivision of
systems is only allowed if the energy is metered at the system boundary. This requirement ensures that
the resulting indicators follow the physical energy flows. If the user of the standard wants to set
deviating requirements for the subdivision of systems (e.g. contractual solutions) they shall be
presented via a table following the format of EN 15316-4-5:2017, Table A.7.
It may be useful or necessary to divide a system when parts of the district energy network are operated
by different utility companies or with different system parameters.

Key
A conversion device of consuming system  B energy consumer
C conversion device of supplying system  D boundary of consuming system
E boundary of supplying system
Figure 1 — district energy system divided into subsystems – example 1
If the energy indicators of the supplier system cannot be calculated but at least the input energy carrier
and the type of conversion device is known default values from the annex of EN 15316-4-5:2017 may be
used. Missing input data may be the case when the purpose of the conversion device is not primarily
heating or the system operator does not measure the required energy input data.
Key
A conversion device of supplying system  B energy consumer
C conversion device of consuming system  D boundary of supplying system
E boundary of consuming system
Figure 2 — district energy system divided into subsystems – example 2
Example 2 is an appropriate division of a connected system if conversion device C is e.g. a biomass CHP
operated by a different utility company supplying only a part of the customers. It is appropriate because
the system operator who invests in more expensive fuels or technology should have the benefit from
the energy performance calculation.

Key
A conversion device of heating system B energy consumer
C conversion device of DHW system D boundary of DHW system
E boundary of heating system
Figure 3 — district energy system divided into subsystems – example 3
Example 3 shows a 4-pipe system with two pipes for heating (system boundary E) and two pipes for
domestic hot water service with a supplementary heating device, e.g. solar thermal (system boundary
D).
6 Calculation methods for energy performance indicators
6.1 Simplified approach
Each district energy system is unique. So it is not possible to indicate an appropriate calculation rule for
each single case, energy carrier or technology. The calculation rules have to be universal. The basic
principle that is described in EN 15316-4-5:2017, 6.1, is universal and can be applied to any scheme. As
long as the system boundaries are clearly defined and all energy carriers that cross the system
boundary are considered, the basic principle leads to reasonable results. (Exception: district heating
system including much electricity from non-cogeneration mode, see 6.2.2.1.4) The flexibility of this
approach and the different resulting options are illustrated by the following examples of a district
biogas system. The biogas is generated within the system boundaries. In a second step it is upgraded by
generation unit D to biomethane to match the requirements of a natural gas grid.

Key
A system boundary district biogas system  1 energy input biomass
B energy consumer  2 auxiliary electricity input
C biogas generation unit  3 auxiliary heat input
D biomethane generation unit  4 delivered biogas
5 delivered biomethane
Figure 4 — basic principles illustrated by an example of a district biogas system
a) The biomethane generation unit is regarded as an energy consumer outside the assessment
boundary. The amount of biogas that is exported to the biomethane generation unit is regarded as
delivered biogas and thus added to the denominator. The weighting factors of the biomethane have
to be calculated separately.
b) The biomethane generation unit is inside the assessment boundary. Biomethane is the delivered
energy carrier and therefore in the denominator.
c) The biomethane generation unit is inside the assessment boundary. Biogas is regarded as the
delivered energy carrier. Biomethane is exported from the system so it becomes a multi-output
system. The allocation of weighted energy flows to the outputs can either be based on conventions
or on mathematical allocation methods that use the energy flows as input data. The easiest
convention is to set a default value for the weighting factors of the exported biomethane. This could
be e.g. the marginal weighting factor of the national gas grid.
The second example is a system that delivers heating and cooling. A heat generator produces heat, a
chiller produces cooling and a heat pump produces heating and cooling. For the simplified approach
only energy flows that cross the system boundary are required (quantities 1, 2, 3, 8 and 9). The
simplified approach can be applied in three different ways:
Key
A system boundary 1 energy input to heat generator
B energy consumer 2 electricity input heat pump
C heat generator 3 electricity input chiller
D heat pump 4 heat output heat generator
E chiller 5 heat output heat pump
6 cooling output heat pump
7 cooling output chiller
8 heat delivered by the system
9 cooling delivered by the system
Figure 5 — basic principles illustrated by an example of a district heating and cooling system
d) district heating is regarded as the main product of the system and its weighting factor is required
for the assessment of the connected buildings. Cooling is exported to another system or area and is
counted as a bonus. The weighting factors of the exported cooling can either be default values
based on conventions or be calculated based on the avoided weighted energy in the external
system.
e) district cooling is regarded as the main product of the system and its weighting factor is required
for the assessment of the connected buildings. Heat is exported to another system or area and is
counted as a bonus. The weighting factors of the exported heat can either be default values based
on conventions or be calculated based on the avoided weighted energy in the external system.
f) heating and cooling are delivered to the same customers and are assessed together with the same
weighting factors. This case is an example for the combination of systems according to
EN 15316-4-5:2017, 6.2.3 and Table B.6. If both a specific weighting factor for heating and a specific
weighting factor for cooling are required, the detailed calculation rule according to
EN 15316-4-5:2017, 6.2.2.4 has to be applied. For this calculation quantities 5 and 6 are required:
Calculation examples for district heating, cooling and district electricity can be found in Annex V.
6.2 Detailed calculation rules
6.2.1 General
The division into generation-related and distribution-related calculation rules reflects that in many
cases these system parts are operated by different utilities or different divisions of a company. If the
energy that is delivered from the generation part to the distribution part of the system can be
determined, improvement potentials of the overall system can be identified.
6.2.2 Generation-related calculation rules
6.2.2.1 Cogeneration of heat and power
6.2.2.1.1 General
The aim of the calculation procedure is the energy performance indicators of cogenerated heat. Thus
the energy flows of the CHP unit have to be identified step by step.
Some methods in 6.2.2.1 require the exclusion of non-cogenerated heat from the calculation (power
loss, power loss simple, power loss ref, alternative production and carnot). CHP units that can produce
non-cogenerated heat are gas turbines with a heat recovery boiler with an integrated auxiliary firing,
steam turbines with a bypass to the condenser and stirling engines. Systems without any of these
devices usually don’t include non-cogenerated heat, thus the related energy flows don’t have to be
identified.
Some methods in 6.2.2.1 require the exclusion of non-cogenerated electricity from the calculation
(power bonus, alternative production and residual heat). Systems without any device to release heat to
the environment (e.g. cooling tower) usually don’t include non-cogenerated electricity, thus the related
energy flows don’t have to be identified.
6.2.2.1.2 Heat-related energy flows of the non-cogeneration mode
In case of a gas turbine with a heat recovery boiler with an integrated auxiliary firing identifying the
non-cogenerated heat is possible because the auxiliary firing is usually equipped with a gas meter. The
related heat can be estimated by assuming a conservative efficiency of η = 0,95.
T;ncm
In case of a steam turbine with a bypass to the condenser identifying the non-cogenerated heat is
possible if the steam bypass is equipped with a steam meter. The related fuel can be determined by
using the efficiency of the boiler which is usually known.
6.2.2.1.3 Identifying the operation mode of the electricity production
The default values for η in EN 15316-4-5:2017, Table B.9 are taken from the directive 2012/27/EU
ref,tot
Annex I. The purpose of this Annex is the calculation of electricity from cogeneration and the fuel
savings by the CHP unit according to Annex II. They may be changed to higher values by the Member
States.
The default values for η in EN 15316-4-5:2017, Table B.9 may be changed by the user of the
ref,tot
standard if presented in a Table according to the template in EN 15316-4-5:2017, Annex A. Setting a
lower value would have the following effect:
A CHP unit that does not utilize all the heat but dumps it to the environment via cooling tower or
bypassing the heat exchanger of the chimney has a lower overall efficiency. This might be the case when
the CHP unit does not only follow the heat demand but also follows sometimes the electricity demand.
The result of the energy performance calculation of the heat with the power bonus method, the
alternative production method and the residual heat method can be distorted if the non-cogeneration
part of the electricity and the respective fuel input are not excluded from the calculation. This depends
on
— the difference between the electric efficiency of the CHP unit and the electric efficiency that is
reflected by the weighting factor of exported electricity (power bonus method);
— the difference between the electric efficiency of the CHP unit and the electric efficiency of the
reference electricity production η (residual heat method);
el;ref
— the difference between the electricity that was produced in full cogeneration mode and the
electricity that was produced in non-cogeneration mode.
The default values for η should be high enough to ensure that the non-cogeneration part is
ref,tot
negligible in the energy performance calculation of the heat.
6.2.2.1.4 Electricity-related energy flows of the cogeneration mode
The calculation of the energy flows of the cogeneration mode is only required if the overall efficiency is
too low to assume operation in full cogeneration mode. The procedure is related to the mix/hybrid
mode and is further described in Commission decision 2008/952/EC. Figure 6 shows the calculation
flow:
Quantities 1, 10 and 11 in Figure 6 (in bold) can be measured;
Quantities 5 and 9 in Figure 6 (in dotted lines) are known from the previous calculation step;
The power-to-heat ratio σ and the electric efficiency in non-cogeneration mode η are required as
el,ncm
additional input data;
Quantities 3 and 4 are the energy input in cogeneration mode;
Quantities 7 and 8 are the energy output in cogeneration mode;
Quantities 2 and 6 shall be excluded from the calculation.
Figure 6 — Calculation flow chart for the CHP energy flows
A calculation example can be found in B.4.
The calculation of quantity 4 is subject of EN 15316-4-5:2017, 6.2.2.1.5 and 6.2.2.1.6.
6.2.2.1.5 Weighting factors for heat
6.2.2.1.5.1 General
The power bonus method and power loss simple method are the most established methods in many
countries for decades. They are also described in EN 15316-4-5:2017. Both they require an external
electricity reference system. It is not possible to calculate the specific weighting factor of the produced
electricity because this indicator is an input to these calculation methods.
6.2.2.1.5.2 Power bonus method
This method is applicable for all cogeneration units. The electricity-related energy flows of the non-
cogeneration mode can distort the result for the heat so they have to be identified (6.2.2.1.3) and
excluded (6.2.2.1.4) from the calculation.
The method can also be expressed with efficiency indicators instead of energy amounts. This facilitates
the calculation of planned systems in an early stage of the planning phase.
11+⋅σ CHR ⋅ f − CHR ⋅ f σ ⋅ CHR − β ⋅ f
( ) ( ) ( )
we;cr;chp we;cr; gen hn we;el;exp
f +− (1)
we;dh
η ⋅⋅η ηη η
chp;tot hn gen;T hn hn
where
η is the efficiency of the heating network
hn
η is the efficiency of the supplementary heat generator
gen;T
β E / Q
hn el;hn pr
where
E is the auxiliary electricity of the heating network
el;hn
The first term represents the primary energy input to a CHP unit, the second term represents the
primary energy input to a supplementary heat generator, the third term represents the electricity
production of the CHP unit. If the system set-up includes more generators, Formula (1) has to be
adjusted accordingly.
6.2.2.1.5.3 Power loss simple method
The power loss simple method can only be applied if the heat is extracted from a condensation turbine.
It is the only method to calculate performance indicators for heat from nuclear power plants because
the method does not require E as input data.
in
6.2.2.1.6 Weighting factors for heat and electricity
6.2.2.1.6.1 General
The methods in this clause facilitate also the calculation of the weighting factors of the produced
electricity. Example calculations can be found in B.5.
6.2.2.1.6.2 Power loss method
The power loss method is applicable if the heat is extracted from a condensation turbine. It is the only
method that facilitates the determination of the real expenditure of heat production in a cogeneration
unit without any external reference systems. It is based on specific data of the cogeneration unit and
thus reflects the efficiencies of its technical components. It is well known and accepted among power
plant operators and scientists as thermodynamically correct. It is based on the idea that the amount of
fuel that is related to the lost electricity production due to heat extraction shall be allocated to the heat.
=
The power loss method does not require the exclusion of the electricity-related part of the non-
cogeneration mode.
6.2.2.1.6.3 Carnot method
The carnot method is a simplified version of the exergy method. It requires temperatures as additional
input data. These are easy to measure. It is recommended to use the outdoor air temperature at the
plant site. For systems with modulating supply temperatures it is recommended to use a monthly
calculation interval. Systems with a constant supply temperature can be calculated on an annual basis.
The mean temperature of the CHP-heat can easily be calculated from the supply and return
temperatures at the outlet of the plant site or at the outlet of the CHP unit if available. If the return
temperature is not available ΔT = 20 K can be assumed. In case of a steam supply system the steam
temperature is used. Data from external reference systems is not required. The carnot method does not
require the exclusion of the electricity-related part of the non-cogeneration mode. It can be applied to
all cogeneration units. The basic idea is related to the power loss method but it is more based on the
physical concept of exergy. It determines the exergy content of the heat and compares it with the
produced electricity to allocate the fuel.
6.2.2.1.6.4 Alternative production method
The alternative production method requires two external reference systems and the exclusion of both
the electricity-related and heat-related energy flows of the non-cogeneration mode. The method
allocates much more fuel to the heat than the other methods. This results in rather low electricity
factors. Especially CHP units with rather low electric efficiency are misinterpreted as CHP units with
rather high electric efficiency. So the method seems to violate the second law of thermodynamics.
However it is described in the standard because there are already cases of application and it is
applicable for statistical purposes where only aggregated data are available.
6.2.2.1.6.5 Residual heat method
This method follows the same idea as the power bonus method but facilitates the determination of
electricity factors. The only difference to the power bonus method is that the external reference system
is represented by the efficiency of the electricity production instead of the primary energy factor. In
case of a single CHP unit that produces electricity only in full cogeneration mode, the combination of the
Formulae (1), (10) and (15) results in
f
P;cr
E ⋅−f E ⋅
in;cr P;cr el;cm
η
el;ref
f = (2)
P,dh
∑ Q
del
while the power bonus method in the form of Formula (2) becomes
E ⋅−f E ⋅ f
in;cr P;cr el;cm P;el;exp
f = (3)
P,dh
∑ Q
del
so if the CHP unit utilizes the same fuel as the reference system, the results of the two methods are the
same.
6.2.2.1.6.6 Power loss ref method
This method follows the same idea as the power loss simple method but facilitates the determination of
electricity factors. The only difference to the power loss simple method is that the external reference
system is represented by the efficiency of the electricity production instead of the primary energy
factor. In case of a single CHP unit that produces heat only in full cogeneration mode, the combination of
the Formulae (1), (10) and (16) results in
f
P;cr
∆E ⋅
el
η
el;ref
f = (4)
P;dh
∑ Q
del
while the power loss simple method integrated in Formula (1) becomes
∆Ef⋅
el P;el;exp
f = (5)
P;dh
∑ Q
del
so if the CHP unit utilizes the same fuel as the reference system, the results of the two methods are the
same.
6.2.2.1.7 Overview and summary
In EN 15316-4-5:2017, Table A.11 method selection criteria can be found. The choice of allocation
methods shall be presented in a table that follows this format. Table B.11 shows informative default
methods.
This clause is intended to support the process of deciding a table according to EN 15316-4-5:2017,
Table A.11 by summarizing the main characteristics of the methods. The following questions are
considered as relevant for the selection:
— Is the determination of the non-cogeneration part mandatory? The determination of the non-
cogeneration part can be time-consuming if σ, η or η are not available. It is considered
T,ncm el,ncm
positive if this procedure is not required by the method. It keeps the application simple.
— Is the calculation of specific electricity weighting factors possible? In the vast majority of cases the
electricity weighting factors of CHP units cannot be used in the EPB calculation today because the
electricity is exported to the grid and is not used for EPB services. Only a small amount of CHP
electricity is dedicated to EPB-services in a building. However it would be positive for these cases to
have the option to calculate electricity weighting factors.
— Is the method applicable to all kinds of CHP units? There are three methods that are only applicable
for CHP units that have a power loss due to heat extraction, i.e. steam extraction condensing
turbines. Selecting one of these methods means that it has to be complemented by a second method
for all other kinds of CHP units. Selecting more than one method can either be positive or negative.
— Is an external reference system required? Finding an appropriate reference system is associated
with an extensive analysis of the interactions between the CHP unit and the reference system. The
analysis often requires additional conventions and assumptions that can have a high impact on the
result. The complexity of this process can easily lead to less accurate analysis and inappropriate
provisions. It is considered positive if external reference systems are not required by the method.
The following figure shows the impact of external reference systems on the calculation result for
the expenditure factor of the CHP heat e . (e = 1/ η ).
T T T
Key
1 power bonus method
2 power loss simple method
3 residual heat method
4 power loss ref method
5 alternative production: heat factor
6 alternative production: electricity factor
Figure 7 — impact of external reference systems on performance indicators of CHP heat
Table 3 — characteristics of the methods
Power
Power Power Alternative Residual Power
loss Carnot
bonus loss production heat loss ref
simple
exclusion of the
heat-related part of
the non- no yes yes yes yes no yes
cogeneration mode
mandatory?
exclusion of the
electricity-related
part of the non- yes no no no yes yes no
cogeneration mode
mandatory?
external reference
yes yes no no yes yes yes
system required?
calculation of
specific electricity
no no yes yes yes yes yes
weighting factors
possible?
applicable to all
yes no no yes yes yes no
kinds of CHP units?
In EN 15316-4-5:2017, Table B.11, the CEN option can be found. Power bonus is selected for the
calculation of heat weighting factors because
— it is well established in many countries;
— it was already described in EN 15316-4-5:2007;
— there is an extensive analysis providing an appropriate electricity weighting factor on national and
European level;
— it is the default method in EN ISO 52000-1:2017 for CHP units in buildings;
— does not require the identification of the heat-related non-cogeneration mode.
The CEN option also provides the power loss method because it;
— does not require external input data;
— does not require the identification of the electricity-related non-cogeneration mode;
— is thermodynamically correct; and
— is established and well accepted among plant operators.
The carnot method was selected because it combines the characteristics of the power loss method with
universal applicability. The results of power loss and carnot are in a comparable range.
Example calculations can be found in B.5. The calculations are conducted for one single CHP unit with
all seven allocation methods and three different fuel factors. The summary of the results is shown in
Figure 8.
Key
1 power bonus
2 power loss simple
3 power loss
4 carnot / residual heat
5 alternative production
6 power loss ref
Figure 8 — primary energy factors for heat calculated with different allocation methods and
fuels
7 Setting default values
7.1 Single-output systems
Primary energy factors reflect the expenditure to deliver one unit of an energy carrier.

Key
A energy source in nature  1 total primary energy E
Ptot
B upstream chain of energy  2 non-renewable primary energy EPnren
supply
C consumer area, point of  3 renewable primary energy E
Pren
delivery
4 non-renewable infrastructure embedded energy Enren,infra
5 renewable infrastructure embedded energy Enren,infra
6 non-renewable energy to extract, refine, convert and E
nren,upstr
transport
7 renewable energy to extract, refine, convert and transport Enren,upstr
8 delivered non-renewable energy E
nren,del
9 delivered renewable energy E
nren,del
Figure 9 — upstream energy flows and related losses
If all the losses and energy expenditure along the upstream chain are allocated to the same energy
carrier (single-output system), the total primary energy factor exceeds unity (f ≥ 1). Primary
Ptot,sos
energy factors can be determined according to existing database programs or life-cycle-assessment-
tools. It is a convention to include or exclude the infrastructure embedded energy (energy to build the
transportation and conversion facilities). EN ISO 52000-1:2017, Table B.22 excludes the infrastructure
embedded energy.
It is a convention if the non-renewable primary energy is used in the EP certificate or the total primary
energy.
It is a convention if the weighting factors are based on NCV or GCV. If national conversion factors for
electricity are derived from national statistics that are based on NCV, heat and fuel factors should also
be based on NCV to maintain a fair competition between heat based, fuel based and electricity based
applications. The CEN option in EN ISO 52000-1:2017, Table B.22 is NCV. If GCV is used also the
electricity factors shall be based on GCV. However it shall be clearly stated in a table that follows the
format of EN ISO 52000-1:2017, Table A.22.
The default values for heat from boilers (fossil and biomass) in EN 15316-4-5:2017, Table B.2 lines 1-6
are based on calculation according to
ββ+⋅ f
f
( )
gen hn we;el
we;cr
f + (6)
we;T
ηη⋅ η
gen;th hn hn
where
β E / Q of the boiler
gen el;aux pr
Input data and resulting default values can be found in Annex A. The input data are conservative.
Considering the high number of assumptions on the input data it wouldn’t be appropriate to pretend a
high accuracy of the resulting values, so the default values are rounded to emphasize their default
character.
7.2 Multi-output systems
Energy flows from multi-output systems require additional conventions how to allocate the primary
energy to the delivered energies.
=
...