CEN/TR 15316-6-6:2017

SLOVENSKI STANDARD
01-maj-2018
(QHUJLMVNHODVWQRVWLVWDYE0HWRGD]DL]UDþXQHQHUJLMVNLK]DKWHYLQXþLQNRYLWRVWL
VLVWHPDGHO5D]ODJDLQXWHPHOMLWHY(10RGXOD0LQ0
Energy performance of buildings - Method for calculation of system energy performance
and system efficiencies - Part 6-6: Explanation and justification of EN 15316-4-3, Module
M3-8-3, M8-8-3
Heizungsanlagen und Wasserbasierte Kühlanlagen in Gebäuden - Verfahren zur
Berechnung der Energieanforderungen und Nutzungsgrade der Anlagen - Teil 6-6:
Begleitende TR zur EN 15316-4-3 (Wärmeerzeugungssysteme, thermische Solar- und
Photovoltaikanlagen)
Ta slovenski standard je istoveten z: CEN/TR 15316-6-6:2017
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
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 15316-6-6
TECHNICAL REPORT
RAPPORT TECHNIQUE
April 2017
TECHNISCHER BERICHT
ICS 27.160; 91.120.10; 91.140.10
English Version
Energy performance of buildings - Method for calculation
of system energy performance and system efficiencies -
Part 6-6: Explanation and justification of EN 15316-4-3,
Module M3-8-3, M8-8-3
Heizungsanlagen und Wasserbasierte Kühlanlagen in
Gebäuden - Verfahren zur Berechnung der
Energieanforderungen und Nutzungsgrade der
Anlagen - Teil 6-6: Begleitende TR zur EN 15316-4-3
(Wärmeerzeugungssysteme, thermische Solar- und
Photovoltaikanlagen)
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 15316-6-6:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols and subscripts . 7
5 Information on the methods . 7
5.1 General . 7
5.2 Solar thermal methods . 7
5.3 Photovoltaic applications . 8
6 Method description . 8
6.1 Solar thermal applications . 8
6.1.1 Method 1 – monthly, using system test data . 8
6.1.2 Method 2 – monthly, using component specifications . 11
6.1.3 Method 3 – hourly, using component data . 19
6.2 Solar photovoltaic applications . 22
7 Method selection . 22
8 Worked out examples . 22
8.1 Solar thermal applications . 22
8.1.1 Method 1 – using system test data . 23
8.1.2 Method 2 – monthly, using component specifications . 25
8.1.3 Method 3 – hourly, using component specifications . 28
9 Application range . 30
9.1 Energy performance. 30
9.1.1 Solar thermal applications . 30
9.1.2 Solar photovoltaic applications . 30
9.2 Energy certificate . 30
9.2.1 Solar thermal applications . 30
9.2.2 Solar photovoltaic applications . 31
9.3 Inspection . 31
9.3.1 Solar thermal applications . 31
9.3.2 Solar photovoltaic applications . 32
9.4 Recommendations (tailored rating) . 32
9.4.1 Solar thermal applications . 32
9.4.2 Solar photovoltaic applications . 32
9.5 Building or system complexity . 32
9.5.1 Solar thermal applications . 32
9.5.2 Solar photovoltaic applications . 32
10 Regulation use . 32
11 Information on the accompanying spreadsheet . 33
12 Results of the validation tests . 33
13 Quality issues . 33
A.1 Method 1 – thermal solar, using system data . 34
A.2 Method 2 (monthly) . 36
A.3 Method 3 (hourly) . 37
B.1 Example 1, method 2 . 38
B.1.1 Input data and summary of results . 38
B.1.2 Detailed results for the hot water service . 38
B.1.3 Detailed results for the space heating function . 39
Bibliography . 42

European foreword
This document (CEN/TR 15316-6-6:2017) 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 16628:2014, 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 [17].
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 [19] that laid the
foundation for the preparation of the set of EPB standards.
1 Scope
This Technical Report refers to EN 15316-4-3, Modules 3-8 and 8-8.
It contains information to support the correct understanding, use and national adaptation of
EN 15316-4-3.
This Technical Report does not contain any normative provision.
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 15316-4-3:2017, Energy performance of buildings — Method for calculation of system energy
requirements and system efficiencies — Part 4-3: Heat generation systems, thermal solar and photovoltaic
systems, Module M3-8-3, M8-8-3, M11-8-3
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)
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 15316-4-3:2017 (the accompanied EPB standard) apply.
4 Symbols and subscripts
For the purposes of this document, the symbols and subscripts given in EN ISO 52000-1:2017 and in
EN 15316-4-3:2017 apply.
5 Information on the methods
5.1 General
The standard describes six methods for solar applications for intended use in buildings. The methods
one to three refer to solar thermal applications and the methods four to six refer to photovoltaic
applications.
5.2 Solar thermal methods
Method 1 is used for solar thermal applications if (only) system test data according to EN 12976-2 is
available. This is commonly the case for solar system types for which the component specifications
cannot be determined separately. An example of this is a so called Integrated Collector Storage system
(= ICS).
The system test result, the annual performance of the system, for the actual climate conditions is
interpolated to the actual heat demand. Optionally the annual performance is distributed over the
month, using the distribution of the solar irradiance on the collector plane as the key. The method 1 is
limited to the generation of heat for the service domestic hot water production.
Method 2 is used for solar thermal applications if component specifications for the collector and heat
storage are available. This is commonly the case for solar thermal for intended use in buildings.
Examples of this are solar domestic hot water systems and combi-systems.
The method 2 applies the so called Fchart method [3] to calculate the monthly performance using the
component specifications and system design parameters as input. The method 2 is applicable for the
services water heating and space heating. The method 2 is intended for use with a monthly time step.
Method 3 is used for solar thermal applications if component specifications for the collector and heat
storage are available. Method 3 applies an hourly numerical calculation method to determine the solar
loop output to the storage tank. The method 3 is intended to be used in combination with EN 15316-5.
The combination of the two methods is applicable for the services water heating and space heating.
5.3 Photovoltaic applications
6 Method description
6.1 Solar thermal applications
6.1.1 Method 1 – monthly, using system test data
6.1.1.1 General
The effect of a thermal solar system on the energy performance of a building comprises of:
— heat output to the distribution systems for domestic hot water, thus reducing the buildings
consumption of other (e.g. conventionally generated) heat;
— recovered losses used for space heating, thus reducing the buildings consumption of heat for space
heating;
— electricity to be supplied, thus increasing the buildings consumption of electricity;
— reduction of operation time of the conventional heating generator. In some cases, the conventional
back-up heater can be turned off during summer, thus reducing stand-by thermal losses and
auxiliary electricity consumption.
6.1.1.2 Rationale
Method 1 uses system test data for the product technical input data. The system test data are derived
from a test result according to EN 12976-2 or according to EN 12977-2.
The test method following EN 12976-2 consists of two steps:
1. system test;
The goal of the system test is to determine the whole system performance parameters determined
from dynamic operating conditions.
2. annual performance calculation.
The performance parameters are combined with a simplified, standardized, calculation model to
calculate the performance for (e.g.) one year for specific reference climate and heat use conditions.
Method 1 requires two sets of the annual performance for the climate conditions applicable. One
for a lower or equal and one with a higher heat use than applicable. By means of linear
interpolation the annual performance for the applicable heat use is derived from these results.
The test method following EN 12977-2 consists of two steps:
3. component tests;
The main components of the system are tested according to EN ISO 9806 and EN 12977-3 or
EN 12977-4.
4. annual performance calculation.
The component test results are applied in a simulation calculation model to determine the annual
system performance.
In case of a preheater system, the output of the method (Q ) quantifies the heat output of an
W;bu;out
external water heater needed to complete the heat use.
In case of a solar-plus-supplementary system, the output of the method (Q ) quantifies the heat
W;bu;out
output of an external heater connected to the hot water storage tank to complete the heat use.
A flow chart of the calculation method is given in A.1.
NOTE The method is limited to systems applied for the heating of domestic hot water.
6.1.1.3 Time steps
The time step of the method is one month or one year.
6.1.1.4 Assumptions
The output data over the months of the year are assumed to be distributed proportional with the
monthly solar irradiation.
The system test result takes into account all component performances and system design parameters of
the tested system. The values of the individual performance determinants are not tested and are as
such not available for method 1. For this reason necessary extra performance parameters are estimated
based on the primary test results.
— The heat losses of the solar heating designated part of the heat storage tank to determine the
recoverable heat losses. Both determinant parameters (storage volume and heat losses) are not
known form the test results and need to be estimated.
The storage tank volume is assumed to be equal to the daily volume of domestic hot water
extracted from the storage tank. The calculation assumes a temperature difference between the
cold water and hot water of 50 K.
Q
W;sol;us
V ⋅413,4 (1)
sto
t
ci
The storage heat loss coefficient is assumed to be the maximum value within the label class C of the
Commission Delegated Regulation (EU) No 812/2013.
0,4
16,66+⋅8,33 V
sto
U = (2)
sto
Simplifying gives:
=
0,4
Q 
W ;sol;us
U= 0,37+⋅2,06
sto  
t
ci
 
The heat losses of the storage tank are calculated for a storage temperature of 60 °C and multiplied
with the solar fraction (Q / Q ).
W;sol;out W;sol;us
— The heat losses of the backup heating designated part of the heat storage tank to determine the
recoverable heat losses.
The main portion of the storage heat losses origin from the backup heating designated part of the
storage tank (solar-plus-supplementary systems only). The heat losses are estimated following the
same method as for the solar part of the storage, but without multiplying with the solar fraction.
6.1.1.5 Data input
6.1.1.5.1 Product technical data
Be aware that the performances related to heat are defined in MJ. For that reason the outputs of
EN 12976-2 need to be transformed to kWh.
Table 1 — Product technical data
Standard Catalogue
Symbol Unit Symbol Unit Description Remarks
W kWh Q MJ auxiliary energy Test result.
W;sol;aux;an par
consumption
Q kWh Q MJ energy required for Condition for which the test
W;sol;us;an d
service domestic hot results are valid.
water.
SOL_LAYOUT = SER only:
Q kWh Q MJ Solar output Test result.
W;sol;out;an L
SOL_LAYOUT = PAR only:
Q kWh Q MJ Backup heater contribution Test result.
W;bu;an aux;net
to the heat use
6.1.1.5.2 Operational conditions
Table 2 — Operational conditions
Symbol Unit Description Remarks
February is assumed to have 28
tci h Calculation time step
days.
I W/m Average solar irradiation on the collector plane
sol;S45
ϑ °C Average outside air temperature
outside
Q kWh Energy required for service domestic hot water
W;sol;us
W kWh Output of the backup heat
W;bu;aux;nom
Auxiliary energy consumption backup-heater
generator module
QW;bu;ls;nom kWh Output of the backup heat
Heat losses backup heater
generator module
NOTE The values of the operating conditions are determined for the considered calculation period.
6.1.1.6 Simplified input
6.1.1.7 Calculation information
6.1.2 Method 2 – monthly, using component specifications
6.1.2.1 General
The effect of a thermal solar system on the energy performance of a building comprises of:
— heat output of the thermal solar system to the distribution systems (for space heating and/or for
domestic hot water), thus reducing the buildings consumption of other (e.g. conventionally
generated) heat;
— recovered losses from the thermal solar system used for space heating, thus reducing the buildings
consumption of heat for space heating;
— electricity to be supplied to the thermal solar system, thus increasing the buildings consumption of
electricity;
— reduction of operation time of the conventional heating generator. In some cases, the conventional
back-up heater can be turned off during summer, thus reducing stand-by thermal losses and
auxiliary electricity consumption.
6.1.2.2 Rationale
This calculation method, based on the f-chart method (see [2]) with added elements. The method uses
component data and operational data with a time step of one month to calculate the energy
performance of a solar thermal system applied for water heating and/or space heating.
The calculation procedure is described in a flow chart in A.1.
6.1.2.3 Time steps
6.1.2.3.1 Introduction
The time step of the method is one month. Through summation of the monthly results, annual results
can be determined.
6.1.2.3.2 Assumptions
The calculation method is a simplified monthly method, based on the f-chart method (see [3]), with the
following additions.
6.1.2.3.3 Extension with the effect of the heat storage heat losses
The previous edition of the standard did not take into account the heat loss coefficient of the heat
storage tank. In the current version the heat losses of the storage are explicitly taken into account. A
formula for this purpose has been developed and checked by means of model simulation calculations.
The results are shown in Figure 1.
Key
Y (Qst;ls;est – Qst;ls;calc) / Qsol;out
X Qsol;out
Q : calculated heat losses with simulation model
st;ls;calc
Q : estimated heat losses with formula in standards
st;ls;est
Qsol;out: solar contribution to the heat demand
P1 Average deviation
P2 P1 + standard deviation
P3 P1 – standard deviation
Figure 1 — The relative error of the estimated annual heat losses of the storage tank, taking into
account the ƒ factor
app
As a consequence of this addition, the heat use applied to the system is increased with the monthly heat
losses of the tank to allow for a full solar coverage of the heat use.
6.1.2.3.4 Maximum value of factor Y
Although in the latest revision of [3] shows both a upper and lower limit to the calculated factor Y
(Formula (35), the upper limit of 3 is not implemented. Adding this limitation would cause significant
irrational results for low heat uses.
6.1.2.3.5 Solar systems with integrated backup heating
The method 2 has been revised as such that for both preheater type solar systems and solar-plus-
supplementary systems the contribution of the backup heater is determined. For this purpose the heat
losses of the backup part of the hot water storage tank is calculated using the appropriate part of the
total heat loss coefficient of the tank (Formula (32).
The “appropriate part” is calculated, taking into account the control coefficient of the backup heater.
6.1.2.3.6 Space heating distribution system
The solar output for the space heating service is significantly higher for low temperature space heating
emitters compared to high temperature emitters. In order to take this effect into account in the method,
the reference temperature (=ϑref), in the previous version fixed at 100 °C, is made dependent of the
space heating distribution return temperature (=ϑ ) as indicated in Figure 2.
H;ref
The formula used is an educated guess giving a conservative estimation of the intended effect.

Key
x-axis design temperature of the heat emitters (= ϑref)
Y axis reference temperature used in the calculations (= ϑH;ref)
Figure 2 — Relation between the reference temperature and the design temperature of the heat
emitters
6.1.2.3.7 Correction factor
As a consequence of introducing the effect of the storage heat losses, the solar thermal performance will
decrease with the calculated heat losses of the storage. To compensate for this effect a factor (=ƒ ) is
app
introduced by which the solar contribution of the heat demand is multiplied.
Key
x-axis Label class of the hot water storage tank (0 means no heat losses
y-axis Fraction of the solar output if the heat losses are not taken into account
L1 Ratio storage volume and collector area = 40 l/m
L2 Ratio storage volume and collector area = 60 l/m
Figure 3 — decrease of the solar output due to the introduction of the formula for the heat losses
of the storage tank
Assuming that the hot water heat storage tanks are typically of a C or D type, the average decrease of
the solar contribution to the heat demand is 8 %. Consequently the correction factor ƒ is set to 1,08.
app
6.1.2.3.8 Solar-combi systems
A solar combi-system outputs heat for both water heating and space heating. The general calculation of
solar output applies individually for space heating and for domestic hot water, assuming that one part
of the system is used for space heating and another part is used for domestic hot water.
This functional division of the system is accounted for by designating part of the collector area and
storage volume to each function, proportional to the monthly space heating use and the domestic hot
water use, respectively.
6.1.2.4 Data input
6.1.2.4.1 Product technical data
Table 3 — Product technical data
Symbol Description Unit Reference Default values
A Collector aperture area m none
sol;mod
η zero loss collector -
o
efficiency
EN 12975
Annex A of the standard.
a first order collector heat W/(m .K)
EN ISO 9806
Other values can be specified in
loss coefficient
a national annex
2 2
a second order collector W/(m .K )
heat loss coefficient
IAM Incidence angle modifier -
(50°)
Psol;pmp collector pump electrical W Pump Annex A of the standard.
power consumption documentation
Other values can be specified in
a national annex
V nominal storage volume l none
st;tot
Vst;bu backup designated part of l none
EN 12977–3
the storage
or
H stand-by heat losses of the W/K Annex A of the standard.
st;ls;tot
EN 12977–4
storage
Other values can be specified in
or
a national annex
energy label on tank
U the heat exchanger heat W/K Annex A of the standard.
st;hx
transfer value in the
Other values can be specified in
collector loop
a national annex
The parameters A , η , a , a and IAM are available from the manufacturer. In case of unavailability
sol;mod o 1 2
of the collector module area, A is set as the total measured collector aperture area and N is set at
sol;mod col
the value of 1.
The definition of the collector pump energy consumption takes into account the operating mode of the
pump in order to account for the effect of a power controlled pump. The value should represent the
average power consumption of the collector pump during system operation time.
For thermosyphon systems the collector pump power is set to zero.
In case of the application of two storage tanks, one for the water heating service and one for the space
heating service, the above storage input data are specified for each individual tank.
In case of separate tank(s) for the solar heat storage and the backup heat storage, the tank for backup
heat storage is assumed to be part of the (external) backup heater and is not taken into account in the
solar thermal method. In this case V = 0.
st;bu
In case of a preheater system, the backup heating volume is set to zero.
In case of an energy label on the storage tank ((EU) No 812/2013) the stated heat losses in the product
fiche can be used.
6.1.2.4.2 System design data
6.1.2.4.2.1 Orientation and shadowing of the collectors
The effect of a none-optimal location of the collector is taken into account by a correction factor (=ƒ ),
col
that is defined in Annex A of the standard for three situations. A national annex can specify this
correction differently, whilst taking into account the collector tilt angle, orientation and shadowing by
surrounding obstacles.
6.1.2.4.2.2 Collector loop heat loss
The overall heat loss coefficient of all pipes in the collector loop (= H ), including pipes between
loop;p
collectors and pipes between collectors and the collector array and solar storage tank in W/K.
The value can be calculated from the details of the collector loop design. Default values are given in
Annex A of the standard. Other default values can be specified in a national annex
6.1.2.4.2.3 Efficiency of the collector loop
The efficiency of the collector loop (= η ) can be calculated using the input data. Default values are
loop
given in Annex A of the standard. Other values ca be specified in a national annex.
6.1.2.4.2.4 The collector pump operation time
The annual operation time of the collector pump (= t ) has been is specified in Annex A of the standard
aux
by a default value. The collector pump operation time is dependent of the climatic region of the solar
system. Other values can be specified in a national annex.
6.1.2.4.2.5 Space heating distribution temperature
The space heating distribution return temperature (= Ѳ ) in °C is defined as the annual average
H;dis;rtn
temperature during operation. Default values are given in Annex A of the standard. The value of this
parameter is dependent of the type of heat emitters applied. Other values can be specified in a national
annex.
6.1.2.4.2.6 Recoverable heat losses
The part of the heat losses that effectively decreases the space heating demand of the building is defined
by a default value. Other values can be specified in a national annex.
6.1.2.4.2.7 Overall correction factor
The overall correction factor (=fapp) is introduced in the method to compensate for adding the effect of
the storage heat losses. The default value of 1,08 is determined by model simulation calculations.
This value can also be used to tune the outcome of the method to a higher or lower level (e.g. to level the
performance with other technologies used or in the context of another application of the method).
Other values can be specified in a national annex.
6.1.2.4.2.8 Operating conditions
) and outside air temperature (= ϑ ) are average
The monthly values for solar irradiation (= Isol;s45;m outside;m
values for each month. The cold water temperature is the average annual temperature. The values are
dependent of the climatic region of the solar thermal system application. In Annex A of the standard
default values are given for several European locations. Other values can be specified in a national
annex.
Energy use applied for the domestic hot water system is determined by:
— required energy for domestic hot water needs, including emission losses (see EN 15316-3-1);
— thermal losses from domestic hot water distribution (see EN 15316-3-2).
Default values are given in Annex A of the standard. Other values can be specified in a national annex.
Energy use applied for the space heating system is determined by:
— required space heating needs (see EN ISO 13790);
— thermal losses from space heating emission (see EN 15316-2-1);
— thermal losses from space heating distribution (see EN 15316-2-3).
The service temperature of the hot water (=ϑ ) is defined as the design temperature with which the
W;srv
hot water is used. A default value is given in Annex A of the standard. Other values can be specified in a
national annex.
The hot water temperature (=ϑ ) is defined as the design temperature at the outlet of the backup
W;hw
heater. A default value is given in Annex A of the standard. Other values can be specified in a national
annex.
The thermostat settings of a solar system with an integrated backup heating (combi storage) is defined
for the function water heating and space heating. Typically these parameters have the same value as
given in Annex A of the standard. Other values can be specified in a national annex.
6.1.2.5 Simplified input
6.1.2.6 Calculation information
6.1.2.6.1 Heat balance of the heat generation sub-system, including control
The heat balance of thermal solar system method is given by
Q+QQ +Q + Q +Q +Q
s;sol;in s;bu s;sol;us s;sol;loop;ls s;sol;st;ls s;bu;st;ls s;bu;dis
where
Q solar radiation on the collector area;
s;sol;in
Q backup heater contribution to the heat demand;
S;bu
Q solar contribution to the heat demand;
S;sol;out
Q Heat losses of the collector loop;
s,sol,loop,ls
Q heat losses of the solar designated part of the heat storage;
S;sol;st;ls
Q heat losses of the backup heating part of the heat storage;
S;bu;st;ls
Q heat losses of the backup heater loop;
S;bu;dis;ls
The first index of each symbol (=S) reflects to the type of service of the solar system for which the
output is calculated: water heating (=W) or space heating (=H).
6.1.2.6.2 Calculation outputs
6.1.2.6.2.1 Contributions to the heat use applied
The heat output of the solar thermal system, the requested heat demand (= Q ) and the heat losses,
s;sol;us
are supplied by both the solar contribution (= Q ) and the backup heater contribution (= Q ).
s;sol;in s;bu
The method is valid for two types of solar thermal system layouts:
— the type with integrated backup heating;
The heat storage tank is dual functional and stores heat from both the solar collector loop output
and the backup heater loop. The output of the solar system covers the whole heat demand. The
backup heater can be either an external heat generator or a heat generator integrated in the storage
tank (e.g. emerged electrical resistance heater).
The output value for Q reflects to the requested output of the backup heat generator and Q
s;bu s;bu;st;ls
gives the heat losses of the for backup heating designated part of the heat storage.

QQ= −Q +Q
s;bu s;sol;us s;sol;out s;bu;st;ls
— the preheater type.
=
The heat storage tank stores heat from the collector loop only. An external heater (not included in
the method) supplies the remainder of the heat necessary to cover the complete heat demand.
The output value for Q reflects to the requested output of the external backup heater and Q
s;bu s;bu;st;ls
is in this case equal to zero.
QQ −Q
s;bu s;sol;us s;sol;out
Both W and Q are an output of the external heat generator module. Consequently both
s;bu;nom s;bu;ls;nom
W and Q apply to the external heat generator.
S;bu;aux S;bu;ls
6.1.2.6.2.2 Auxiliary energy consumption
Some thermal solar systems use auxiliary electrical energy and some do not:
— for a thermosiphon system (self-circulation thermal solar system), auxiliary energy consumption is
zero;
— for a forced circulation system, auxiliary energy consumption by pumps and controllers are taken
into account.
NOTE Additional auxiliary energy consumption (e.g. for freezing protection) can be taken into account in national
annexes.
6.1.2.6.2.3 Recoverable, recovered and unrecoverable thermal losses
The calculated thermal losses are not necessarily lost. Parts of the losses are recoverable, and parts of
these recoverable losses are actually recovered.
Recoverable thermal losses are e.g. the thermal losses from the distribution between the thermal solar
sub-system and the back-up heater.
6.1.2.6.2.4 Calculation periods
The objective of the calculation is to determine the monthly heat output of the thermal solar sub-
system. The annual output is obtained by summation of the monthly outputs.
Optionally, but not recommended, annual data for the system operation period can be used by
performing the calculations using annual average values.
6.1.3 Method 3 – hourly, using component data
6.1.3.1 Rationale
The calculation procedure is described in a flow chart in A.1.
In contrast to method 1 and 2, method 3 is limited to the calculation of the output of the solar collector
loop. The method 3 is meant to be used in combination with the storage module 3-7 / 8-7 (EN 15316-5).
The collector loop module together with the storage tank module can handle the three main system
layouts shown in Figure 4, with the following main characteristics.
— Applicable for the service hot water production, space heating or both.
— Three types of backup heating.
A backup heating in series with the solar system, integrated in the solar system or an electrical
integrated heater can be applied.
=
— Multiple heat exchangers.
In each loop connected to the storage a heat exchanger can be applied (or not).
The optional hot water distribution loop is modelled as a extra heat loss in one of the storage
segements.
Key
1 collector loop
2 warm tap water loop
3 space heating loop
4 external space heater
5 external water heater
6 hot water storage tank
7 heat exchanger
8 heat generator
9 electrical immerged heater
Figure 4 — valid solar system designs
6.1.3.2 Time steps
The time step of the method is one hour.
6.1.3.3 Assumptions
The calculation method is a simplified hourly method. The following assumptions are made in order to
simplify the method:
— the condition for finalization of the iteration has been set to a fixed number of four iterations;
This should be good enough for an accurate result, assuming that the iteration is converging.
— the incidence angle modifier at 50° is applied, not taken into consideration the actual angle of
incidence;
This assumption may lead to some inaccuracy for the calculation for one hour, but should not have
an effect on a daily basis.
— the heat losses of the return and supply piping in the collector loop are assumed to be equal;
The effect of this assumption of the end results is expected to be necletable.
— Shadowing of the collector by surrounding obstacles is not taken into account.
A correction for this effect may be described in a national annex.
6.1.3.4 Data input
6.1.3.4.1 General
Table 4 — Product technical data
Symbol Description Unit Reference Default values
Asol;mod Collector aperture area m None
ηo zero loss collector -
efficiency
a1 first order collector heat W/(m .K)
EN 12975
Annex A of the standard.
loss coefficient
EN ISO 9806
Other values can be specified in
a2 second order collector
2 2
a national annex
W/(m .K )
heat loss coefficient
IAM Incidence angle modifier -
(50°)
Psol;pmp collector pump electrical W Pump Annex A of the standard.
power consumption documentation
Other values can be specified in
a national annex
P Collector pump control W Documentation of Annex A of the standard.
sol;ctrl
power consumtpion controler
Other values can be specified in
a national annex
The parameters A , η , a , a and IAM are available from the manufacturer. In case of unavailability
sol;mod o 1 2
of the collector module area, A is set as the tota
...