Bsi bs en 00834 2013 (2015)

3.1 heat cost allocator instrument for registration of the proportionate thermal output of radiators in consumer units 3.2 heat cost allocation system overall system, as verified by

BSI Standards Publication

Heat cost allocators for the determination of the consumption of room heating radiators — Appliances with electrical energy supply

© The British Standards Institution 2015.

Published by BSI Standards Limited 2015ISBN 978 0 580 90351 9

Amendments/corrigenda issued since publication

30 June 2015 Implementation of CEN corrigendum April 2015:

Figure 1 updated

This British Standard is the UK implementation of EN 834:2013, incorporating corrigendum April 2015 It supersedes BS EN 834:1995, which is withdrawn

EUROPÄISCHE NORM

English Version

Heat cost allocators for the determination of the consumption of

room heating radiators - Appliances with electrical energy supply

Répartiteurs de frais de chauffage pour déterminer la

consommation des corps de chauffe - Appareils dotés

d'une alimentation en énergie électrique

Heizkostenverteiler für die Verbrauchserfassung von Raumheizflächen - Geräte mit elektrischer

Energieversorgung

This European Standard was approved by CEN on 28 December 2012

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member

This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions

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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E FÜ R N O R M U N G

Management Centre: Avenue Marnix 17, B-1000 Brussels

Incorporating corrigendum April 2015

Contents

Foreword 4

Introduction 5

1 Scope 5

2 Normative references 6

3 Terms and definitions 6

4 Functional principle and measurement methods 11

5 General specifications 12

5.1 Base condition 12

5.2 c-value 13

5.3 Rating factors 13

5.4 Calendar function 14

6 Requirements for heat cost allocators 15

6.1 Requirements concerning temperature stress 15

6.2 Storage temperature 15

6.3 Start of counting 15

6.4 Idle counting rate 15

6.5 Temperature sensors 15

6.6 Calculator/central processing unit 16

6.7 Auxiliary power supply 16

6.8 Overflow of the display 16

6.9 Display resolution 16

6.10 Functional check 16

6.11 Limits of relative display deviation 17

6.12 Ageing 17

6.13 Electrical, electrostatic and magnetic influences 17

6.14 Thermal impact on heat cost allocators operating in accordance with the single-sensor measurement method 17

6.15 Thermal impact on heat cost allocators operating in accordance with the two-sensor measurement method 17

6.16 Thermal impact on other devices or components 18

6.17 Impact on transmission systems 18

6.18 Sealing 18

6.19 Calendar function 18

6.20 Taking into account operating conditions 18

7 Requirements for use and installation 19

7.1 Temperature limits 19

7.2 Attachment of the sensors 19

7.3 Attachment position of the sensors 20

7.4 Connecting cable installation 20

7.5 Uniformity of heat cost allocators 20

8 Rating requirements 21

8.1 Rating factor KQ 21

8.2 Rating factor KC 21

8.3 Rating factor KT 21

8.4 Resulting rating factor K 21

8.5 c-value 21

9 Requirements for maintenance and reading 22

9.1 Visual reading 22

9.2 Close-range reading 22

9.3 Remote reading 22

10 Testing 22

10.1 General 22

10.2 Test documents 23

10.3 Test report 23

10.4 Test protocols 23

11 Test procedures 23

11.1 Construction test 23

11.2 Sealing test 23

11.3 Temperature durability test 23

11.4 Test for compliance with the limits of the relative display deviation 24

11.5 Ageing resistance test 24

11.6 Test of the start of counting at normal operation and also, for heat cost allocators with room temperature sensors, at operation with thermal impact 24

11.7 Test of the idle counting rate 25

11.8 Test of the counting rate in the case of thermal impact 25

11.9 Test for external influences 26

11.10 Test of c-values, procedure 26

11.11 Test of c-values, scope of testing 26

11.12 Test of rating factor KQ 26

11.13 Test of rating factor KC 27

12 Marking 27

Annex A (informative) Information and recommendations 28

A.1 General 28

A.2 Heating systems 28

A.3 Recommended field of application 28

A.4 Heat emission not controllable by the consumer 29

A.5 Additional corrections 29

A.6 Documentation of the relationship between the counting rate and the thermal output 30

Bibliography 32

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 supersedes EN 834:1994

Amendments

Compared to EN 834:1994, the following changes were made:

a) Definitions, requirements and test procedures have been refined and expanded,

b) Introduction of new values for the lower temperature limit,

c) Uniform definition for the mounting location of heat cost allocators on the radiator

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: 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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom

Introduction

This document deals with heat cost allocators with electrical power supply used for establishing the consumption value of room heating surfaces It specifies the minimum requirements for the construction, materials, production, installation, function and evaluation of the displayed readings established by these measuring devices

This document describes test procedures to establish compliance with the stated requirements and specifies instructions for their nature and scope

1 Scope

NOTE See Clause 3 for a definition of the terms used below

This European standard applies to heat cost allocators which are used to capture the proportionate thermal output of radiators in consumer units

If an account unit comprises consumer units of different types (e.g technically different types of heating systems or differences due to the consumer behaviour, e.g industrial plants as opposed to private apartments), it could be necessary to divide this account unit into groups of users

Heat cost allocators enable the determination of the heat consumption only of each radiator in a consumer unit as a share of the total heat consumption of the account unit or user group (see Clause 4); it is therefore necessary to determine this total heat consumption either by measuring the consumed fuel quantity or the amount of heat delivered (the latter by means of a heat meter, for example)

For the appropriate use of the heat cost allocators in accordance with this standard, the heating system needs to:

 correspond to the state of the art at the time of installation of the heat cost allocators;

 be operated in accordance with the state of the art (see A.2)

This standard specifies that heat cost allocators shall not be used for heating systems where the temperature

of the heating system falls below or exceeds the temperature limits of the heat cost allocators, where the

rating factor for the thermal output, KQ, cannot be clearly specified or where the heating surface is inaccessible This applies usually to the following heating systems:

 floor heating;

 radiant ceiling heating;

 flap-controlled radiators;

 radiators with ventilators;

 fan-assisted air heaters;

 heating systems with steam-operated radiators

2 Normative references

Not applicable

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply

3.1

heat cost allocator

instrument for registration of the proportionate thermal output of radiators in consumer units

3.2

heat cost allocation system

overall system, as verified by an inspection authority, consisting of a heat cost allocator, installation equipment, installation instructions, rating system, existing rating factors, maintenance and reading instructions

3.3

measurement method

physical principle of measurement in combination with fundamental properties of the appliance type

Note 1 to the term: For heat cost allocators in accordance with this standard, the fundamental property of the appliance type characterizing the method is the number of measuring sensors for registering the relevant temperatures The physical principle of measurement which is applied preferably is the temperature dependency of electrical components

mean value of the flow and return temperatures of the heating medium

Note 1 to the term: In this standard, tm is determined by adding up the logarithmic heating medium excess temperature,

Δtln, (formula (2), see 5.2) and the reference air temperature, tL

3.11

mean design heating medium temperature

tm,A

mean value of the design flow temperature and the design return temperature

Note 1 to the term: In this standard, tm,A is determined by adding up the logarithmic mean value of the design excess temperature and the basic reference air temperature of 20 °C in accordance with formula (2) (see 5.2)

3.12

base condition

radiator operating condition which is freely selectable within predefined limits and which is used for specifying

the rating factors and for determining the c-values

3.13

basic reference air temperature

tL,B

value of the air temperature at base condition

Note 1 to the term: For tL,B the specified target value is 20 °C, see 5.1

heating medium base flow

medium flow through the radiator at base condition

3.16

temperature sensors

sensors consisting of a sensor element and a sensor casing, which generate a temperature-dependent signal Note 1 to the term: The sensor casing serves both to transfer heat and to protect the sensor element from mechanical influences

3.17

measuring range of temperature sensors

temperature range within which temperature sensors can be used

Note 1 to the term: For pairs of temperature sensors which are used for the determination of temperature differences, in addition to the measuring range, there is also a temperature difference range

temperature tm,A of the heating system is replaced by the mean design heating medium temperature tm,A of the last

radiator in the string or, as a substitute, the design return temperature tR,A of the string

displayed reading value

measuring value produced by the heat cost allocator which can be read off as a numerical value at the display device

Note 1 to the term: If this value does not equal zero at the beginning of the measuring period, the displayed reading relevant for the heat cost calculation is determined from the difference between the numerical values at the end and the beginning of the measuring period The reading may be a non-rated value or the consumption value (see 3.24)

3.24

consumption value

displayed reading value rated by rating factors

3.25

counting rate

R

progression of the displayed reading or the consumption value per unit of time

Note 1 to the term: When determining the relative display deviation (3.28), the value measured at the temperatures of the operating state is referred to as the actual counting rate

3.26

counting rate characteristic

relationship between the counting rate and, according to measurement method, the temperature or the temperature difference

Note 1 to the term: A distinction is made between the scheduled counting rate characteristic intended during the construction of the heat cost allocator and the actual counting rate characteristic in the appliance type When determining the relative display deviation (3.28), the value of the counting rate determined from the scheduled counting rate characteristic at the temperatures of the operating state is referred to as the scheduled counting rate

3.27

basic counting rate

R B

value of the counting rate resulting from the scheduled counting rate characteristic at the temperature or

temperature difference of the base condition and a c-value of zero

Note 1 to the term: It serves to determine the rating factor KC (see 5.3.2)

3.28

relative display deviation

difference between the actual counting rate and the scheduled counting rate related to the scheduled counting rate

3.29

idle counting rate

counting rate at room temperature without thermal output from the radiator

3.30

reading

making available the displayed reading or the consumption values of the heat cost allocators for the purpose

of heat cost calculation

reading by means of data transfer to a receiver

Note 1 to the term: Usually, the receiver is arranged outside the consumer unit

3.34

reference output

thermal output of the radiator under prescribed operating conditions

factors by which the non-rated displayed reading values of the individual heat cost allocators are multiplied so

as to be able to be used as consumption values directly for the consumer-based billing of heat costs

3.40

resulting rating factor

K

product of the individual rating factors

Note 1 to the term: See also 5.3.3, formula 6

person or organization responsible for the heat cost allocator system and the proper delivery and installation

of the heat cost allocator

4 Functional principle and measurement methods

Heat cost allocators in accordance with this standard are measuring devices for the registration of the temperature integral with respect to time The temperature is the basis for the determination of the heat emission of the room heating surfaces on which the heat cost allocators or their sensors are installed Heat cost allocators with electrical supply as covered by this standard (in the following referred to as heat cost allocators) depending on the measurement method register all or only a part of the characteristic temperatures relevant for the heat emission of the room heating surface The non-rated displayed reading value is the approximate value of the time integral of the measured characteristic temperature of the room heating surface

or the time integral of the temperature difference between the room heating surface and the room

The rated displayed reading value referred to as the consumption value (see 3.24) is obtained (see 5.3) from the non-rated displayed reading value (see 3.23) by multiplication by rating factors, particularly by those for

the reference thermal output of the room heating surface (KQ, see 3.37) and for the thermal contact between

the sensors and the temperatures to be registered (KC, see 3.38)

The consumption value is an approximate value for the heat emitted by the heating surface during the measurement period and the heat consumed by the user The consumption value is either read off directly at the heat cost allocator or determined later by converting the non-rated displayed reading value

The consumption value thus is a measuring result containing properties of the measuring device, room heating surface, other boundary conditions and, in addition, uncertainties of the rating factors and the installation Measuring deviations (measuring errors) of the registered heat therefore do not depend on the measuring device only This means that heat cost allocators cannot be calibrated in the same manner as heat meters

Due to the properties described, the measuring result will not be allocated any physical energy units The consumption value is non-dimensional It is used only as a relative value relating to the sum of the consumption values of the account unit or group of users A relative value of a measured consumption value determined in this manner can be interpreted as a share of the heat consumption of the account unit or user group This quantity is determined after the measurement period has ended for each individual radiator From the sum of the consumption values for the radiators of a consumer unit, the described relative value can be determined as the share of the heat consumption of the relevant consumption unit in the total consumption of the account unit or user group

Heat cost allocators usually consist of a casing, measuring sensors, a calculator unit, a display device, the energy supply, fixing elements and the seal The seal serves to protect the heat cost allocator against unauthorized manipulation The components of the heat cost allocator are manufactured in compliance with certain tolerances Thus, each individual one of a particular kind of heat cost allocator (type, make) functions the same when used in an identical way

Each heat cost allocator in accordance with this standard is a functional unit It fulfils its intended task only as

a whole, with all its components and properties acting in systematic cooperation and together with all other heat cost allocators within the same account unit or group of users Tests of heat cost allocators in accordance with this standard are therefore always system tests, the results of which are only valid for the tested heat cost allocation system as a whole

Heat cost allocators in accordance with this standard work according to one of the following measurement methods

The single-sensor measurement method utilizes one temperature sensor The sensor registers the temperature of the room heating surface or heating medium Appliances with room temperature start sensors fall under the single-sensor measurement method

The two-sensor measurement method utilizes two temperature sensors One sensor registers the temperature

of the room heating surface or heating medium, the second sensor registers the room temperature or a temperature in a defined relation to it

Multiple-sensor measurement methods register a measure of the mean heating medium temperature using at least two radiator sensors and the room temperature using one other sensor The measured values are used for determining the heating medium excess temperature applying a suitable algorithm

5 General specifications

5.1 Base condition

The following applies for the base condition of the radiator:

 upper flow inlet;

 mean heating medium temperature tm = 40 °C to 60 °C;

 basic reference air temperature tL,B = 20 °C, to be measured in a thermally stable test booth at a height of 0,75 m above the floor and a distance of 1,5 m in front of the heating surface; the acceptable deviation from the scheduled value is ± 2 K;

 heating medium base flow which occurs at tL,B = 20 °C and values of tV/tR in accordance with Figure 1 The acceptable tolerance is ± 5 %;

where

tV is the flow temperature in °C;

tR is the return temperature in °C

NOTE Within the acceptable scheduled value deviation for tL,B (see above), the flow and return temperatures tV/tR are

each adjusted such that the excess temperature values of the radiator and the temperature drop tV - tR as given by Figure 1 remain unaltered

Δts is the temperature difference of the sensors, e.g tHS - tRS;

Δt is the heating medium excess temperature tm - tL or Δtln

where

tHS is the temperature of the radiator sensor or radiator sensors;

tRS is the temperature of the room temperature sensor (for heat cost allocators without room temperature

sensors tRS = tL);

tm is the mean heating medium temperature;

tL is the reference air temperature (measuring specification in accordance with 5.1);

tV is the flow temperature of the radiator;

tR is the return temperature of the radiator;

ΔtIn is the logarithmic excess temperature of the heating medium with respect to tL, calculated from the measured values as follows:

L R

L V

R V

ln

t t

c-values are generally determined from measured temperatures As an alternative, it is possible to determine

them by conversion of known c-values, but this usually requires verifying measurements This applies to both the conversion of c-values of known types of heat cost allocators and the derivation of c-values for radiators of

similar type

5.3 Rating factors

The thermal output of a radiator in a thermally stable test booth at flow, return and air temperatures of 90 °C,

70 °C and 20 °C, the air temperature being measured at a height of 0,75 m above the floor and a distance of

1,5 m in front of the heating surface, is the reference output relevant for the rating factor KQ (reference system

If an output value is known in a reference system for the radiator to be rated, this value shall be applied directly If such a value is only available in the corresponding reference system, it shall be converted For the conversion of the reference outputs, the following formulae (3) and (4) shall be applied exclusively

Conversion of a reference output Q(50 K) on the basis of 75 °C/65 °C/20 °C (excess temperature: 50 K) into the reference output Q(60 K) at 90 °C/70 °C/20 °C (excess temperature: 60 K):

where

n is the radiator exponent determined during the radiator test

If the true radiator exponent is not available, n = 1,3 may be used

KC is calculated as the quotient of the basic counting rate RB and the counting rate RR at the temperatures of the sensors on the radiator to be rated operated at base condition:

5.3.3 Resulting rating factor K

The resulting rating factor K is calculated as the product of the individual rating factors:

T C

The processes which are controlled by the calendar function can include the following:

 transmission of displayed reading values or consumption values or other stored values;

 recognition of operating states;

 recording of specific events (e.g errors, thermal impact, appliance opening)

6 Requirements for heat cost allocators

6.1 Requirements concerning temperature stress

Brief occurrences of tmax of the mean heating medium temperature, tm, shall cause no impairment of the proper function of a heat cost allocator or its components installed and ready for service on the radiator This similarly applies to heat cost allocators installed on other surfaces, e.g on pipes

For components not attached to the heating surfaces, ambient temperatures between 0 °C and 50 °C shall not cause any malfunction

6.2 Storage temperature

The construction of all components shall ensure that storage temperatures of between - 25 °C and + 60 °C shall not cause any functional disturbances

6.3 Start of counting

During the thermally uninfluenced heating operation, the following applies:

Appliances operating according to the single-sensor measurement method without room temperature start

sensor shall, on a radiator with c ≤ 0,1 at a heating medium flow corresponding to the base condition (see 5.1) and a reference air temperature of 20 °C, start counting at the temperature tZ in accordance with formulae (7) and (8):

For appliances with room temperature sensors, the criterion for the start of counting given as excess temperature in formula (9) applies to all measurement methods (cf Clause 4):

z t

t

tz = z− L ≤

For appliances operating according to the single-sensor measurement method having a room temperature

start sensor, z = 5 K applies For appliances operating according to the two-sensor measurement method, the values of z given in 7.1.3 apply as a function of tmin

For different types of heating surfaces within one account unit, the start of counting of the individual

appliances may vary by 10 % (tmin—20 °C), but no more than 5 K

6.4 Idle counting rate

At room temperatures of up to 27 °C, the idle counting rate shall not exceed 1 % of the scheduled counting

rate at a heating medium excess temperature of Δt = 60 K, with a heating medium flow corresponding to the

base condition

6.5 Temperature sensors

The mechanical strength and thermal durability of the sensor coating shall be sufficient to prevent deformations during installation, operation and dismantling for inspection purposes, which impair the intended function of the sensor element

For inspection purposes, the instruments or their components shall be capable of being dismantled in such a

The temperature sensors shall satisfy any classified environmental conditions which include a lower

temperature limit of + 5 °C, an upper temperature limit of at least tmax (see 3.18) and an annual mean value of the relative humidity of ≤ 65 %

6.6 Calculator/central processing unit

The mechanical design shall ensure protection against the penetration of solid foreign bodies and keep out tools, wires and similar objects Furthermore, it shall ensure that water dropping vertically onto it has no damaging effect

The requirement for the mechanical strength is an oscillating load at a frequency of (10 to 55 ) Hz, with an acceleration of 20 m/s2

The calculator/central processing unit shall satisfy classified environmental conditions which include a lower temperature limit of 0 °C, an upper temperature limit of 50 °C and an annual mean value of the relative humidity of ≤ 65 %

6.7 Auxiliary power supply

In the case of a battery power supply, the capacity of the battery shall be adequate to ensure trouble free operation for at least three months longer than the period for changing the battery as specified by the manufacturer; a minimum battery capacity of 15 months shall be ensured in any case If the battery voltage drops during this period, the display deviations in accordance with 6.11 shall not be exceeded

6.8 Overflow of the display

Within two consecutive measuring periods (one measuring period usually comprises 12 months), no overflow

of the meter shall occur which would remain unnoticed If counting at the beginning of a measuring period starts at zero, verification for one measuring period is sufficient A radiator operation of 1500 h per year at the highest radiator output intended within the rating system of the heat cost allocator shall form the basis for this

It shall be ensured that this requirement is also met in the case of higher design temperatures than

tV/tR = 90 °C/70 °C

6.9 Display resolution

After 24 hours of operation for a sectional radiator with a reference output of 1 kW (reference system Q(60 K),

see 5.3.1) at a partial-load thermal output corresponding to a logarithmic excess temperature of 35 K and a heating medium flow corresponding to the base condition (see 5.1), the displayed reading value shall be at least 10