Installation of thermal energy meters - Guidelines for the selection, installation and operation of thermal energy meters

The EN 1434 standard provides technical principles and practical advice in selecting, installing and commissioning of thermal energy meters. However, because a standard cannot cover all areas completely, this document assists users of thermal energy meters.

Installation von thermischen Energiemessgeräten - Richtlinien für Auswahl, Installation und Betrieb von thermischen Energiemessgeräten

Compteur d’énergie thermique installation - Lignes directrices pour la sélection, l’installation et le fonctionnement des compteurs d’énergie thermique

Vgradnja merilnikov toplote - Smernice za izbiro, vgradnjo in delovanje merilnikov toplote

General Information

Status
Published
Public Enquiry End Date
30-Nov-2020
Publication Date
02-Mar-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
25-Feb-2021
Due Date
02-May-2021
Completion Date
03-Mar-2021

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SLOVENSKI STANDARD
SIST-TP CEN/TR 13582:2021
01-april-2021
Nadomešča:
SIST CR 13582:2001
Vgradnja merilnikov toplote - Smernice za izbiro, vgradnjo in delovanje merilnikov
toplote
Installation of thermal energy meters - Guidelines for the selection, installation and
operation of thermal energy meters
Installation von thermischen Energiemessgeräten - Richtlinien für Auswahl, Installation
und Betrieb von thermischen Energiemessgeräten
Compteur d’énergie thermique installation - Lignes directrices pour la sélection,
l’installation et le fonctionnement des compteurs d’énergie thermique
Ta slovenski standard je istoveten z: CEN/TR 13582:2021
ICS:
17.200.10 Toplota. Kalorimetrija Heat. Calorimetry
SIST-TP CEN/TR 13582:2021 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 13582:2021

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SIST-TP CEN/TR 13582:2021


CEN/TR 13582
TECHNICAL REPORT

RAPPORT TECHNIQUE

January 2021
TECHNISCHER BERICHT
ICS 17.200.10
English Version

Installation of thermal energy meters - Guidelines for the
selection, installation and operation of thermal energy
meters
Compteur d'énergie thermique installation - Lignes Installation von thermischen Energiemessgeräten -
directrices pour la sélection, l'installation et le Richtlinien für Auswahl, Installation und Betrieb von
fonctionnement des compteurs d'énergie thermique thermischen Energiemessgeräten


This Technical Report was approved by CEN on 4 January 2021. It has been drawn up by the Technical Committee CEN/TC 176.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, 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: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 13582:2021 E
worldwide for CEN national Members.

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SIST-TP CEN/TR 13582:2021
CEN/TR 13582:2021 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Selecting a metering device for thermal energy . 7
4.1 General. 7
4.2 Metrological characteristics . 8
4.3 Environmental classifications . 8
5 Dimensioning . 9
5.1 General. 9
5.2 Determining the thermal energy power . 9
5.3 Thermal energy load . 9
5.4 Thermal energy power for water heating . 10
5.5 Thermal energy power for ventilation and air conditioning systems . 11
5.6 Thermal energy power for cooling systems . 11
5.7 Thermal energy power for engineering purposes . 11
6 Determining the flow rate . 12
6.1 Principles of thermodynamics . 12
7 Selecting a flow sensor for a thermal energy meter . 13
8 Checking the flow sensor design after commissioning . 14
8.1 General. 14
8.2 Operating conditions . 14
8.3 Flow sensors . 15
8.4 Temperature sensors . 20
8.5 Calculators . 23
9 Arranging of meters for thermal energy . 24
9.1 General. 24
9.2 Environment . 24
9.3 Flow sensors . 25
9.4 Temperature sensors . 28
9.5 Calculators . 32
10 Installing thermal energy meters . 33
10.1 General. 33
10.2 Mechanics . 33
10.3 Connecting to pipes . 33
10.4 Electrical connections . 33
10.5 Commissioning . 34
11 Monitoring operation . 34
11.1 General. 34
11.2 Measuring cooling supply using water or anti-freeze mixtures as medium . 34
11.3 Requirements for the system arrangement of cooling measurements . 39
2

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CEN/TR 13582:2021 (E)
12 Other liquids than water . 42
12.1 Introduction . 42
12.2 Physical impact . 42
12.3 Flow measurement . 44
12.4 Temperature difference measurement . 49
12.5 Calculator . 49
Bibliography . 50

3

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SIST-TP CEN/TR 13582:2021
CEN/TR 13582:2021 (E)
European foreword
This document (CEN/TR 13582:2021) has been prepared by Technical Committee CEN/TC 176 “Thermal
energy meters”, the secretariat of which is held by SIS.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

4

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SIST-TP CEN/TR 13582:2021
CEN/TR 13582:2021 (E)
Introduction
Metering devices for thermal energy (heat and cooling meters) are only working correctly and
consistently if the system design considers the minimum and maximum ratings for temperature,
temperature difference and flow rate according to the approved ranges. The metering device should be
selected for the approved legal range and the application area. The thermal energy meter should be
installed according to the valid requirements. During commissioning the thermal energy meter is checked
for both correct installation and full functionality and afterwards sealed against unauthorized opening.
According to the European harmonized standard EN 1434-6 a commissioning is obligatory to ensure that
the metering device accurately measures the planned or predicted consumption.
Installing the metering devices or their sub-assemblies incorrectly (e.g. an incorrect combination of
temperature sensors with non-approved pockets) does not guarantee the measuring accuracy. Hence,
the measurement deviations may exceed the permissible error limits. National calibration laws state that
the metering point operator should ensure that the metering device is set up, connected, handled and
maintained correctly to guarantee the measuring accuracy. Incorrect measurements result in bills that
cannot be used in business transactions.
The metering point operator is in district heating networks responsible for a proper installation and
commissioning of the metering devices. The metering point operator can also delegate this task to a
service company. The building owner or the building owner’s representative (e.g. a metering service
company) is in sub metering applications responsible for a proper installation and commissioning of the
metering devices.
The EN 1434 standards provide technical principles and practical advice in selecting, installing and
commissioning of thermal energy meters. However, because a standard cannot cover all areas
completely, this report shall assist users of thermal energy meters.
5

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SIST-TP CEN/TR 13582:2021
CEN/TR 13582:2021 (E)
1 Scope
The EN 1434 standards provide technical principles and practical advice in selecting, installing and
commissioning of thermal energy meters. However, because a standard cannot cover all areas
completely, this document assists users of thermal energy meters.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 1434-1, Thermal energy meters - Part 1: General requirements
EN 1434-2, Thermal energy meters - Part 2: Constructional requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1434-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
DH (network)
district heating system, DC: district cooling system
3.2
meter: thermal energy meter
heat meter or cooling meter
3.3
water
domestic water
3.4
hot water
domestic hot water
3.5
fluid additive
fluid used to supplement a shortage of the heat transfer medium due to leaks
3.6
fluid
heat transfer medium in a DH/DC system
3.7
MID
Measurement Instrument Directive 2014/32/EU
6

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4 Selecting a metering device for thermal energy
4.1 General
A thermal energy meter consists of the following three parts: a flow sensor, a temperature sensor pair
and a calculator (see Figure 1).
These sub-assemblies can be defined as complete instruments, combined instruments or hybrid
instruments (see EN 1434-1).
The calculator unit calculates the energy consumption using the signals from the temperature sensor pair
and the flow sensor.
The minimum temperature difference of the calculator shall not fall below the smallest permissible value
(according to MID the minimum temperature difference is 3 K).
The temperature sensors are usually platinum resistance thermometers of type Pt 100, Pt 500 or Pt 1000.
The sensor pair determines the temperature difference between the inlet (flow) and outlet (return) of
the thermal conveying medium.
The flow sensor is granted an error limit of 2 % to 5 %. Due to faulty design, incorrect installation or wear
the wider error limits of this part/sub-assembly of a meter is exceeded occasionally. This case can be
avoided by selecting the correct flow sensor. An overview of the different types of flow sensors is given
in 8.3.7.

Key
1 inlet
2 outlet
3 calculator
4 outlet temperature sensor
5 inlet temperature sensor
6 flow sensor
7 thermal load
Figure 1 — Thermal energy meter
When operating the heat exchanger circuit system, one may discover that the chosen thermal energy
meter design is not applicable due to the actual requirements.
7

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CEN/TR 13582:2021 (E)
Flow sensors that are designed for higher flow rates may not have the required accuracy at low flow rates.
If the actual flow rate is below the minimum permissible flow rate, measurements may be skipped until
the measurement fails completely.
Fast changes in energy consumption that place high demands on the dynamics of the meter may cause
significant deviations in the measurement accuracy of the accumulated energy. Fast-response meters
provide measurement characteristics that reduce this deviation (see 8.5.4)
The effects of dirt deposits and flow disturbances over the entire service life of the flow sensors shall be
considered when selecting a meter.
4.2 Metrological characteristics
The accuracy classes and the maximum permissible relative errors of thermal energy meters are
described in EN 1434-1. Be aware that some national regulations do not allow the use of class 3 meters
3
at all and that other national regulations do not allow the use of class 3 meters for e.g. for q 6 m /h and
p
higher.
Class 2 accuracy is the most frequently used accuracy class for flow sensors.
Due to the very high requirements on both flow sensors and test equipment, the availability of class 1
flow sensors is very limited.
4.3 Environmental classifications
The environmental classes are described in EN 1434-1. Thermal energy meters have an environmental
classification A, B and C regarding Domestic/Industrial EMC requirements and Indoor/Outdoor ambient
conditions.
Table 1 — Relationship between EN 1434-1 and MID re. EMC levels
 EN 1434-1 MID (2014/32/EU)
Domestic EMC level Class A and B E1
Industrial EMC level Class C E2
Meters with Class C (E2) marking can be used also in domestic installations, but meters with Class A and
B (E1) shall not be used in industrial installations (see Table 1).
Classes A and C are defined for indoor installations with +5 °C to 55 °C ambient temperature.
Class B is defined for outdoor installation. Since the availability of thermal energy meters for outdoor
installation is limited, special care shall be taken to select a suitable meter or to select a suitable protective
cabinet.
Most thermal energy meters are installed in locations without any vibration. For such installations,
meters with the mechanical class M1 are suitable. In case some vibrations may occur at the installation
site a meter with class M2 shall be selected. In case of more intense vibrations a meter with class M3 shall
be selected (see Table 4 for more details).
8

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5 Dimensioning
5.1 General
When selecting a thermal energy meter, it is important to determine the upper and lower flow limits for
the flow sensor as required by the operating conditions. Based on the range for nominal flow q and
p
minimum flow q one needs to select a suitable flow sensor from the various devices offered by different
i
manufacturers. This selection results in the nominal diameter of the measuring line where the flow
sensor shall be installed.
Simply selecting a flow sensor according to the nominal diameter of an existing pipe is not necessarily
correct. Otherwise the coverage of the lower flow range may be insufficient.
It is often good practice that flow sensor sizes of one nominal diameter smaller than the pipe are chosen
when the expected average flow rates are low.
The thermal energy output commissioned with the customer and the maximum inlet and outlet
temperature for the planned application build the base for calculating the thermal energy supply.
In transfer stations for district heating and cooling, the fluid flow rate shall be limited to the
commissioned value by using a flow rate limiter and/or a differential pressure controller. The controller
protects the consumer circuit and the flow sensor from overloading. Arrange the controller in series after
the flow sensor in the outlet to avoid additional disturbances in the flow profile before the flow sensor.
The expected yearly average flow rate, when known, should preferably be around 2/3 of the nominal
flow q of the flow sensor. As for each flow sensor size the nominal flow q corresponds with about 2 m/s
p p
average flow velocity. This is the basis for the relationship between DN and q , and it minimizes the risk
p
of cavitation as well as loss of accuracy due to wrong meter size.
5.2 Determining the thermal energy power
The metering point operator should perform calculations to determine the thermal energy power only as
a check. Contracted values shall be specified by the customer exclusively.
5.3 Thermal energy load
5.3.1 Standard thermal energy load in new builds
The standard heat load in new buildings and major redevelopments should be determined by a qualified
project engineer, e.g. according to EN 12831-1:2017, Clause 6.
5.3.2 Thermal energy load of buildings with no standard load calculation
If existing buildings are being connected to a thermal energy supply with no standard load calculation,
one could use an approximation or estimation method to determine the thermal energy load for
dimensioning the flow sensor.
If a building connected to a district heating or cooling supply already contains a central heating system,
an approximate thermal energy load can be calculated from an average of the last three years’ annual
consumption, an outside-temperature (see Figure 2) and the expected full usage hours.
Maximum values stored in the thermal energy meter can also be used to determine the output.




9

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SIST-TP CEN/TR 13582:2021
CEN/TR 13582:2021 (E)
Distribution of outdoor temperatures for five European locations, 1881–2000. An indoor temperature has
been added as example.

Key
X hours per year
Y temperature, °C
1 Palermo, Italy
2 Florence, Italy
3 Strasbourg, France
4 Helsinki, Finland
5 Kiruna, Sweden
6 effective indoor temperature 17 °C
1)
Figure 2 — Outdoor temperature duration in Europe
5.4 Thermal energy power for water heating
The thermal energy power for water heating usually needs to be determined by a qualified project
engineer according to accepted engineering standards (e.g. EN 12831-1).
Using a priority control for the water heating and taking advantage of the building’s heat storage capacity
it may be possible to provide the required thermal energy output for short-term peaks of water heating
without having a significant drop in room temperature.
If a priority control is used the qualified project engineer can select the higher value of the required
thermal energy power between the thermal energy output for central heating or cooling and the thermal
energy power for water heating. The higher value is the deciding factor in the selection of the flow sensor.
Parallel operations shall be considered separately.

1) Source reference: Svend Frederiksen, Svend Werner. 2013. District Heating and Cooling. Studenterlitteratur
AB, Lund. Source reference: Figure 4.2 from “District Heating and Cooling” Svend Frederiksen, Svend Werner
ISBN 978-91-44-08530-2.
10

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CEN/TR 13582:2021 (E)
See Figure 3 for outdoor temperature duration in Europe.

Key
X number of normal apartments
Y required power (kW)
2)
Figure 3 — Outdoor temperature duration in Europe
5.5 Thermal energy power for ventilation and air conditioning systems
The thermal energy power required for ventilation and air conditioning systems should be calculated by
a qualified project engineer.
Depending on climatic requirements, the flow sensor may encounter flow rate peaks during the low load
season if there are ambient inlet temperatures in the district thermal energy network. These peaks shall
be investigated and considered for dimensioning the flow sensor.
5.6 Thermal energy power for cooling systems
In bifunctional systems the flow sensor shall be selected by the maximum flow required for either heat
or cooling. The power should be calculated by a qualified project engineer.
5.7 Thermal energy power for engineering purposes
When supplying heating or cooling for industrial and commercial engineering, it is recommended that
the requirements of the customer and the customer’s qualified project engineer regarding the flow sensor
design are checked. A modulating operating curve in the district thermal energy network can cause
increased flow rate values, especially when there are power peaks in the low load season. This shall be
considered when dimensioning the flow sensor.

2) Source reference: Svend Frederiksen, Svend Werner. 2013. District Heating and Cooling. Studenterlitteratur
AB, Lund. Source reference: Figure 4.2 from “District Heating and Cooling” Svend Frederiksen, Svend Werner
ISBN 978-91-44-08530-2
11

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CEN/TR 13582:2021 (E)
6 Determining the flow rate
6.1 Principles of thermodynamics
6.1.1 General
The nominal heat or cooling load specifies the thermal energy power required at the measuring point in
the (projected) application.
The maximum thermal energy released or absorbed by a thermal conveying medium in a heating or
cooling circuit is calculated as follows:

Q= kV⋅⋅θθ− (1)
( )
io
where

is the thermal energy power, e.g. kW;

Q
3

is the flow rate of the thermal conveying medium, in m /h;
V
3
k is the thermal coefficient, in kWh/m K;
θ is the design temperature in inlet, in °C;
i
θ is the design temperature in outlet, in °C.
o
Convert the formula to calculate the flow rate for the design case.


Q
V= (2)
k⋅θθ−
( )
io
6.1.2 Total maximum power for heating or cooling
Add the outputs specified in Clause 5 to calculate the total thermal energy power.
n

QQ=
(3)
tot
i

i=1
where
 is the total thermal energy power, in kW;
Q
tot
 is the standard thermal load, in kW;
Q

1
 is the thermal power for hot water heating, in kW;
Q
2

 
Q Q
NOTE     If using priority control, use only the larger value, either or .
1 2
 is the thermal energy power for ventilation and air conditioning systems, in kW;
Q
3
 is the thermal energy power for engineering purposes, in kW.
Q
4
12

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For cooling systems, the thermal load has to be added the same way (identical).
6.1.3 Inlet and outlet temperature
The difference between inlet and outlet temperatures is the temperature difference.
 
∆=Θθ −θ K (4)
inlet outlet 
In general, the inlet temperature of the heating or cooling medium is regulated by the outside
temperature and the outlet temperature is based on the design and operating mode of the heating system.
6.1.4 Thermal coefficient
The thermal coefficient k shall be determined according to EN 1434-1. For example, with θ = 100 °C,
inlet
3
θ = 50 °C the approximate value of 1,15 [kWh/(m K)] can be expected for outlet meters and
outlet
3
1,12 [kWh/(m K)] for inlet meters.
7 Selecting a flow sensor for a thermal energy meter
Because the design case described above occurs only for a few days of the year, a flow sensor shall be
selected so that it ensures that the smallest possible deviation occurs over the whole range of the year.
The range of the most frequent flow values (main operation range) at the measuring point is the deciding
factor for selecting the flow sensor.
The operating range of the flow sensor shall be within the approved range which is spread between the
smallest flow q and the nominal flow q .
i p
A flow sensor shall be selected to fulfil all the following criteria:
— the nominal flow q of the flow sensor is as close as possible to the calculated flow rate;
p
— the minimum flow q of the flow sensor is smaller than/equal to the minimum flow of the thermal
i
energy circuit;
— the maximum flow q of the flow sensor is reserved for short term overload (1 hour per day; 200
s
hours per year) in the thermal energy circuit.
If the minimum flow rate of the thermal energy circuit is not covered by the minimum flow q of the flow
i
sensor, it shall be checked whether a smaller flow sensor will cover the design case better.
To achieve the minimum flow rate of the thermal energy circuit, a flow sensor with a higher dynamic
range, q /q , shall be selected.
p i
The nominal flow q shall not be exceeded when selecting the flow sensor.
p
Selecting a flow sensor may be easier if technical measures are taken to reduce the fluctuation range of
the flow.
When selecting a flow sensor statutory regulations and standards, such as EN 1434, the operating
conditions, the manufacturer’s installation instructions and nationally applicable requirements shall all
be considered.
The nominal pressure level (PN/PS) of the flow sensor shall correspond to the pressure class at the
measuring point. In praxis the average pressure should be well below PN.
The permissible temperature range of the flow sensor shall comply with the temperature range of the
thermal conveying medium as well as the ambient temperature at the measuring point. Because of
temperature stress, the flow sensor should generally be installed in the outlet. This is the cooler pipe for
flow sensors in heat meters and this is the warmer pipe for cooling meters.
13

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SIST-TP
...

SLOVENSKI STANDARD
kSIST-TP FprCEN/TR 13582:2020
01-november-2020
Vgradnja merilnikov toplote - Smernice za izbiro, vgradnjo in delovanje merilnikov
toplote
Installation of thermal energy meters - Guidelines for the selection, installation and
operation of thermal energy meters
Installation von thermischen Energiemessgeräten - Richtlinien für Auswahl, Installation
und Betrieb von thermischen Energiemessgeräten
Compteur d’énergie thermique installation - Lignes directrices pour la sélection,
l’installation et le fonctionnement des compteurs d’énergie thermique
Ta slovenski standard je istoveten z: FprCEN/TR 13582
ICS:
17.200.10 Toplota. Kalorimetrija Heat. Calorimetry
kSIST-TP FprCEN/TR 13582:2020 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TP FprCEN/TR 13582:2020

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kSIST-TP FprCEN/TR 13582:2020


FINAL DRAFT
TECHNICAL REPORT
FprCEN/TR 13582
RAPPORT TECHNIQUE

TECHNISCHER BERICHT

September 2020
ICS 17.200.10
English Version

Installation of thermal energy meters - Guidelines for the
selection, installation and operation of thermal energy
meters
Compteur d'énergie thermique installation - Lignes Installation von thermischen Energiemessgeräten -
directrices pour la sélection, l'installation et le Richtlinien für Auswahl, Installation und Betrieb von
fonctionnement des compteurs d'énergie thermique thermischen Energiemessgeräten


This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee CEN/TC
176.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a Technical Report.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TR 13582:2020 E
worldwide for CEN national Members.

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kSIST-TP FprCEN/TR 13582:2020
FprCEN/TR 13582:2020 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Selecting a metering device for thermal energy . 7
4.1 General. 7
4.2 Metrological characteristics . 8
4.3 Environmental classifications . 8
5 Dimensioning . 9
5.1 General. 9
5.2 Determining the thermal energy power . 9
5.3 Thermal energy load . 9
5.4 Thermal energy power for water heating . 10
5.5 Thermal energy power for ventilation and air conditioning systems . 11
5.6 Thermal energy power for cooling systems . 11
5.7 Thermal energy power for engineering purposes . 11
6 Determining the flow rate . 12
6.1 Principles of thermodynamics . 12
7 Selecting a flow sensor for a thermal energy meter . 13
8 Checking the flow sensor design after commissioning . 14
8.1 General. 14
8.2 Operating conditions . 14
8.3 Flow sensors . 14
8.4 Temperature sensors . 20
8.5 Calculators . 23
9 Arranging of meters for thermal energy . 24
9.1 General. 24
9.2 Environment . 24
9.3 Flow sensors . 26
9.4 Temperature sensors . 28
9.5 Calculators . 32
10 Installing thermal energy meters . 33
10.1 General. 33
10.2 Mechanics . 33
10.3 Connecting to pipes . 33
10.4 Electrical connections . 33
10.5 Commissioning . 34
11 Monitoring operation . 34
11.1 General. 34
11.2 Measuring cooling supply using water or anti-freeze mixtures as medium . 34
2

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kSIST-TP FprCEN/TR 13582:2020
FprCEN/TR 13582:2020 (E)
11.3 Requirements for the system arrangement of cooling measurements . 39
12 Other liquids than water . 41
12.1 Introduction . 41
12.2 Physical impact . 42
12.3 Flow measurement . 44
12.4 Temperature difference measurement . 49
12.5 Calculator . 49
Bibliography . 50

3

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kSIST-TP FprCEN/TR 13582:2020
FprCEN/TR 13582:2020 (E)
European foreword
This document (FprCEN/TR 13582:2020) has been prepared by Technical Committee CEN/TC 176
“Thermal energy meters”, the secretariat of which is held by SIS.
This document is currently submitted to the Vote on TR.
4

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kSIST-TP FprCEN/TR 13582:2020
FprCEN/TR 13582:2020 (E)
Introduction
Metering devices for thermal energy (heat and cooling meters) are only working correctly and
consistently if the system design considers the minimum and maximum ratings for temperature,
temperature difference and flow rate according to the approved ranges. The metering device should be
selected for the approved legal range and the application area. The thermal energy meter should be
installed according to the valid requirements. During commissioning the thermal energy meter is checked
for both correct installation and full functionality and afterwards sealed against unauthorized opening.
According to the European harmonized standard EN 1434-6 a commissioning is obligatory to ensure that
the metering device accurately measures the planned or predicted consumption.
Installing the metering devices or their sub-assemblies incorrectly (e.g. an incorrect combination of
temperature sensors with non-approved pockets) does not guarantee the measuring accuracy. Hence,
the measurement deviations may exceed the permissible error limits. National calibration laws state that
the metering point operator should ensure that the metering device is set up, connected, handled and
maintained correctly to guarantee the measuring accuracy. Incorrect measurements result in bills that
cannot be used in business transactions.
The metering point operator is in district heating networks responsible for a proper installation and
commissioning of the metering devices. The metering point operator can also delegate this task to a
service company. The building owner or the building owner’s representative (e.g. a metering service
company) is in sub metering applications responsible for a proper installation and commissioning of the
metering devices.
The EN 1434 standards provide technical principles and practical advice in selecting, installing and
commissioning of thermal energy meters. However, because a standard cannot cover all areas
completely, this report shall assist users of thermal energy meters.
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1 Scope
The EN 1434 standards provide technical principles and practical advice in selecting, installing and
commissioning of thermal energy meters. However, because a standard cannot cover all areas
completely, this document assists users of thermal energy meters.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
prEN 1434-1:2020, Thermal energy meters - Part 1: General requirements
EN 1434-2, Thermal energy meters - Part 2: Constructional requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in prEN 1434-1 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
DH (network)
district heating system, DC: district cooling system
3.2
meter: thermal energy meter
heat meter or cooling meter
3.3
water
domestic water
3.4
hot water
domestic hot water
3.5
fluid additive
fluid used to supplement a shortage of the heat transfer medium due to leaks
3.6
fluid
heat transfer medium in a DH/DC system
3.7
MID
Measurement Instrument Directive 2014/32/EU
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4 Selecting a metering device for thermal energy
4.1 General
A thermal energy meter consists of the following three parts: a flow sensor, a temperature sensor pair
and a calculator (see Figure 1).
These sub-assemblies can be defined as complete instruments, combined instruments or hybrid
instruments (see prEN 1434-1).
The calculator unit calculates the energy consumption using the signals from the temperature sensor pair
and the flow sensor.
The minimum temperature difference of the calculator shall not fall below the smallest permissible value
(according to MID the minimum temperature difference is 3 K).
The temperature sensors are usually platinum resistance thermometers of type Pt 100, Pt 500 or Pt 1000.
The sensor pair determines the temperature difference between the inlet (flow) and outlet (return) of
the thermal conveying medium.
The flow sensor is granted an error limit of 2 % to 5 %. Due to faulty design, incorrect installation or wear
the wider error limits of this part/sub-assembly of a meter is exceeded occasionally. This case can be
avoided by selecting the correct flow sensor. An overview of the different types of flow sensors is given
in 8.3.7.

Key
1 inlet
2 outlet
3 calculator
4 flow sensor
5 inlet temperature sensor
6 outlet temperature sensor
7 thermal load
Figure 1 — Thermal energy meter
When operating the heat exchanger circuit system, one may discover that the chosen thermal energy
meter design is not applicable due to the actual requirements.
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Flow sensors that are designed for higher flow rates may not have the required accuracy at low flow rates.
If the actual flow rate is below the minimum permissible flow rate, measurements may be skipped until
the measurement fails completely.
Fast changes in energy consumption that place high demands on the dynamics of the meter may cause
significant deviations in the measurement accuracy of the accumulated energy. Fast-response meters
provide measurement characteristics that reduce this deviation (see 8.5.4)
The effects of dirt deposits and flow disturbances over the entire service life of the flow sensors shall be
considered when selecting a meter.
4.2 Metrological characteristics
The accuracy classes and the maximum permissible relative errors of thermal energy meters are
described in prEN 1434-1. Be aware that some national regulations do not allow the use of class 3 meters
3
at all and that other national regulations do not allow the use of class 3 meters for e.g. for q 6 m /h and
p
higher.
Class 2 accuracy is the most frequently used accuracy class for flow sensors.
Due to the very high requirements on both flow sensors and test equipment, the availability of class 1
flow sensors is very limited.
4.3 Environmental classifications
The environmental classes are described in prEN 1434-1. Thermal energy meters have an environmental
classification A, B and C regarding Domestic/Industrial EMC requirements and Indoor/Outdoor ambient
conditions.
Table 1 — Relationship between prEN 1434-1 and MID re. EMC levels
 prEN 1434-1 MID (2014/32/EU)
Domestic EMC level Class A and B E1
Industrial EMC level Class C E2
Meters with Class C (E2) marking can be used also in domestic installations, but meters with Class A and
B (E1) shall not be used in industrial installations (see Table 1).
Classes A and C are defined for indoor installations with +5 °C to 55 °C ambient temperature.
Class B is defined for outdoor installation. Since the availability of thermal energy meters for outdoor
installation is limited, special care shall be taken to select a suitable meter or to select a suitable protective
cabinet.
Most thermal energy meters are installed in locations without any vibration. For such installations,
meters with the mechanical class M1 are suitable. In case some vibrations may occur at the installation
site a meter with class M2 shall be selected. In case of more intense vibrations a meter with class M3 shall
be selected (see Table 6 for more details).
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5 Dimensioning
5.1 General
When selecting a thermal energy meter, it is important to determine the upper and lower flow limits for
the flow sensor as required by the operating conditions. Based on the range for nominal flow q and
p
minimum flow q one needs to select a suitable flow sensor from the various devices offered by different
i
manufacturers. This selection results in the nominal diameter of the measuring line where the flow
sensor shall be installed.
Simply selecting a flow sensor according to the nominal diameter of an existing pipe is not necessarily
correct. Otherwise the coverage of the lower flow range may be insufficient.
It is often good practice that flow sensor sizes of one nominal diameter smaller than the pipe are chosen
when the expected average flow rates are low.
The thermal energy output commissioned with the customer and the maximum inlet and outlet
temperature for the planned application build the base for calculating the thermal energy supply.
In transfer stations for district heating and cooling, the fluid flow rate shall be limited to the
commissioned value by using a flow rate limiter and/or a differential pressure controller. The controller
protects the consumer circuit and the flow sensor from overloading. Arrange the controller in series after
the flow sensor in the outlet to avoid additional disturbances in the flow profile before the flow sensor.
The expected yearly average flow rate, when known, should preferably be around 2/3 of the nominal
flow q of the flow sensor. As for each flow sensor size the nominal flow q corresponds with about 2 m/s
p p
average flow velocity. This is the basis for the relationship between DN and q , and it minimizes the risk
p
of cavitation as well as loss of accuracy due to wrong meter size.
5.2 Determining the thermal energy power
The metering point operator should perform calculations to determine the thermal energy power only as
a check. Contracted values shall be specified by the customer exclusively.
5.3 Thermal energy load
5.3.1 Standard thermal energy load in new builds
The standard heat load in new buildings and major redevelopments should be determined by a qualified
project engineer, e.g. according to EN 12831-1:2017, Clause 6.
5.3.2 Thermal energy load of buildings with no standard load calculation
If existing buildings are being connected to a thermal energy supply with no standard load calculation,
one could use an approximation or estimation method to determine the thermal energy load for
dimensioning the flow sensor.
If a building connected to a district heating or cooling supply already contains a central heating system,
an approximate thermal energy load can be calculated from an average of the last three years’ annual
consumption, an outside-temperature (see Figure 2) and the expected full usage hours.
Maximum values stored in the thermal energy meter can also be used to determine the output.
Distribution of outdoor temperatures for five European locations, 1881–2000. An indoor temperature has
been added as example
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Key
X hours per year
Y temperature, °C
1 Palermo, Italy
2 Florence, Italy
3 Strasbourg, France
4 Helsinki, Finland
5 Kiruna, Sweden
6 effective indoor temperature 17 °C
1)
Figure 2 — Outdoor temperature duration in Europe
5.4 Thermal energy power for water heating
The thermal energy power for water heating usually needs to be determined by a qualified project
engineer according to accepted engineering standards (e.g. EN 12831).
Using a priority control for the water heating and taking advantage of the building’s heat storage capacity
it may be possible to provide the required thermal energy output for short-term peaks of water heating
without having a significant drop in room temperature.
If a priority control is used the qualified project engineer can select the higher value of the required
thermal energy power between the thermal energy output for central heating or cooling and the thermal
energy power for water heating. The higher value is the deciding factor in the selection of the flow sensor.
Parallel operations shall be considered separately.

1) Source reference: Svend Frederiksen, Svend Werner. 2013. District Heating and Cooling. Studenterlitteratur
AB, Lund. Source reference: Figure 4.2 from “District Heating and Cooling” Svend Frederiksen, Svend Werner
ISBN 978-91-44-08530-2
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Key
X number of normal apartments
Y required power (kW)
2)
Figure 3 — Outdoor temperature duration in Europe
5.5 Thermal energy power for ventilation and air conditioning systems
The thermal energy power required for ventilation and air conditioning systems should be calculated by
a qualified project engineer.
Depending on climatic requirements, the flow sensor may encounter flow rate peaks during the low load
season if there are ambient inlet temperatures in the district thermal energy network. These peaks shall
be investigated and considered for dimensioning the flow sensor.
5.6 Thermal energy power for cooling systems
In bifunctional systems the flow sensor shall be selected by the maximum flow required for either heat
or cooling. The power should be calculated by a qualified project engineer.
5.7 Thermal energy power for engineering purposes
When supplying heating or cooling for industrial and commercial engineering, it is recommended that
the requirements of the customer and the customer’s qualified project engineer regarding the flow sensor
design are checked. A modulating operating curve in the district thermal energy network can cause
increased flow rate values, especially when there are power peaks in the low load season. This shall be
considered when dimensioning the flow sensor.

2) Source reference: Svend Frederiksen, Svend Werner. 2013. District Heating and Cooling. Studenterlitteratur
AB, Lund. Source reference: Figure 4.2 from “District Heating and Cooling” Svend Frederiksen, Svend Werner
ISBN 978-91-44-08530-2
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6 Determining the flow rate
6.1 Principles of thermodynamics
6.1.1 General
The nominal heat or cooling load specifies the thermal energy power required at the measuring point in
the (projected) application.
The maximum thermal energy released or absorbed by a thermal conveying medium in a heating or
cooling circuit is calculated as follows:

Q= kV⋅⋅θθ− (1)
( )
io
where

is the thermal energy power, e.g. kW;
Q
3

is the flow rate of the thermal conveying medium, in m /h;
V
3
k is the thermal coefficient, in kWh/m K;
θ is the design temperature in inlet, in °C;
i
θ is the design temperature in outlet, in °C.
o
Convert the formula to calculate the flow rate for the design case.


Q
V= (2)
k⋅θθ−
( )
io
6.1.2 Total maximum power for heating or cooling
Add the outputs specified in Clause 5 to calculate the total thermal energy power.
n

QQ= (3)
tot
i

i=1
where
 is the total thermal energy power, in kW;
Q
tot

is the standard thermal load, in kW;
Q
1

is the thermal power for hot water heating, in kW;
Q
2
 

NOTE     If using priority control, use only the larger value, either Q or Q .
1 2

is the thermal energy power for ventilation and air conditioning systems, in kW;
Q
3

is the thermal energy power for engineering purposes, in kW.
Q
4
For cooling systems, the thermal load has to be added the same way (identical).
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6.1.3 Inlet and outlet temperature
The difference between inlet and outlet temperatures is the temperature difference.
∆=Θθ −θ K (4)
inlet outlet
 
In general, the inlet temperature of the heating or cooling medium is regulated by the outside
temperature and the outlet temperature is based on the design and operating mode of the heating system.
6.1.4 Thermal coefficient
The thermal coefficient k shall be determined according to prEN 1434-1:2020. For example, with
3
θ = 100 °C, θ = 50 °C the approximate value of 1,15 [kWh/(m K)] can be expected for outlet meters
inlet outlet
3
and 1,12 [kWh/(m K)] for inlet meters.
7 Selecting a flow sensor for a thermal energy meter
Because the design case described above occurs only for a few days of the year, a flow sensor shall be
selected so that it ensures that the smallest possible deviation occurs over the whole range of the year.
The range of the most frequent flow values (main operation range) at the measuring point is the deciding
factor for selecting the flow sensor.
The operating range of the flow sensor shall be within the approved range which is spread between the
smallest flow q and the nominal flow q .
i p
A flow sensor shall be selected to fulfil all the following criteria:
— the nominal flow q of the flow sensor is as close as possible to the calculated flow rate;
p
— the minimum flow q of the flow sensor is smaller than/equal to the minimum flow of the thermal
i
energy circuit;
— the maximum flow q of the flow sensor is reserved for short term overload (1 hour per day; 200
s
hours per year) in the thermal energy circuit.
If the minimum flow rate of the thermal energy circuit is not covered by the minimum flow q of the flow
i
sensor, it shall be checked whether a smaller flow sensor will cover the design case better.
To achieve the minimum flow rate of the thermal energy circuit, a flow sensor with a higher dynamic
range, q /q , shall be selected.
p i
The nominal flow q shall not be exceeded when selecting the flow sensor.
p
Selecting a flow sensor may be easier if technical measures are taken to reduce the fluctuation range of
the flow.
When selecting a flow sensor statutory regulations and standards, such as EN 1434, the operating
conditions, the manufacturer’s installation instructions and nationally applicable requirements shall all
be considered.
The nominal pressure level (PN/PS) of the flow sensor shall correspond to the pressure class at the
measuring point. In praxis the average pressure should be well below PN.
The permissible temperature range of the flow sensor shall comply with the temperature range of the
thermal conveying medium as well as the ambient temperature at the measuring poin
...

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