One off Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) - Dimensioning

This standard specifies calculations for the dimensioning of Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) based upon the required nominal heat output of the stove as declared by the producer. The Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) are of individual one-off construction design. The standard can be used for log wood fired Kachelöfen (tile stoves) that burn one fuel load per storage period with a maximum load between 10 kg and 40 kg and a storage period (nominal heating time) between 8 h and 24 h.
This standard is valid for Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) equipped with fireclay as interior material, with an apparent density between 1,750 kg/m³ and 2,200 kg/m³, a degree of porosity from 18 % up to 33 % by volume and a heat conductivity from 0,65 W/mK up to 0,90 W/mK (temperature range 20 °C to 400 °C).
This standard is valid for Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) with sidewise combustion air supply of the combustion chamber and an inflow speed from 2 m/s to 4 m/s, whereas the height of the lowest opening is at least 5 cm above the bottom of the combustion chamber.
This standard is not valid for combinations with water heat exchangers for central heating or other heat absorbing elements like glass plates greater than 1/6 of the combustion chamber surface, open water tanks, etc. It is also not valid for combinations with heating/fireplace elements according to EN 13229. Furthermore this standard is not valid for mass-produced prefabricated or partly prefabricated slow heat release appliances according to EN 15250.
NOTE   Although for the purposes of this standard these calculations are applicable only to the requirements of this standard, the same calculations can be used for other purposes, e.g. to verify emission levels and energy efficiency in case of burning log wood or wood briquettes according to the producer’s manual.

Ortsfest gesetzte Kachelgrundöfen/Putzgrundöfen - Auslegung

Poêles en faïence, poêles en maçonnerie fabriqués in situ - Dimensionnement

Lončene peči - Dimenzioniranje

General Information

Status
Not Published
Public Enquiry End Date
02-Nov-2021
Technical Committee
Current Stage
4020 - Public enquire (PE) (Adopted Project)
Start Date
18-Aug-2021
Due Date
05-Jan-2022

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SLOVENSKI STANDARD
oSIST prEN 15544:2021
01-oktober-2021
Lončene peči - Dimenzioniranje
One off Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) - Dimensioning
Ortsfest gesetzte Kachelgrundöfen/Putzgrundöfen - Auslegung
Poêles en faïence, poêles en maçonnerie fabriqués in situ - Dimensionnement
Ta slovenski standard je istoveten z: prEN 15544
ICS:
97.100.30 Grelniki na trdo gorivo Solid fuel heaters
oSIST prEN 15544:2021 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 15544:2021
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oSIST prEN 15544:2021
DRAFT
EUROPEAN STANDARD
prEN 15544
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2021
ICS 97.100.30 Will supersede EN 15544:2009
English Version
One off Kachelgrundöfen/Putzgrundöfen (tiled/mortared
stoves) - Dimensioning

Poêles en faïence, poêles en maçonnerie fabriqués in Ortsfest gesetzte Kachelgrundöfen/Putzgrundöfen -

situ - Dimensionnement Auslegung

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 295.

If this draft becomes a European Standard, 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.

This draft European Standard was established by CEN 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, 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 European Standard. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a European Standard.
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. prEN 15544:2021 E

worldwide for CEN national Members.
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oSIST prEN 15544:2021
prEN 15544:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

Introduction .................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 6

3 Terms and definitions ................................................................................................................................... 6

4 Calculations ....................................................................................................................................................... 8

4.1 Nominal heat output ...................................................................................................................................... 8

4.2 Load of fuel ........................................................................................................................................................ 8

4.2.1 Maximum load .................................................................................................................................................. 8

4.2.2 Minimum load .................................................................................................................................................. 9

4.3 Design of the essential dimensions .......................................................................................................... 9

4.3.1 Combustion chamber dimensions ............................................................................................................ 9

4.3.2 Calculated flue pipe length ....................................................................................................................... 10

4.3.3 Minimum flue pipe length ......................................................................................................................... 11

4.3.4 Gas groove profile ........................................................................................................................................ 12

4.4 Calculation of the burning rate ............................................................................................................... 13

4.5 Fixing of the air ratio .................................................................................................................................. 13

4.6 Combustion air flue gas .............................................................................................................................. 13

4.6.1 General ............................................................................................................................................................. 13

4.6.2 Combustion air flow rate ........................................................................................................................... 13

4.6.3 Flue gas flow rate ......................................................................................................................................... 14

4.6.4 Flue gas mass flow rate .............................................................................................................................. 15

4.7 Calculations of the density ........................................................................................................................ 15

4.7.1 Combustion air density .............................................................................................................................. 15

4.7.2 Flue gas density ............................................................................................................................................. 15

4.8 Calculation of the outside air temperature combustion air temperature and flue gas

temperature ................................................................................................................................................... 16

4.8.1 Mean outside air temperature and combustion air temperature .............................................. 16

4.8.2 Mean combustion chamber temperature ............................................................................................ 16

4.8.3 Flue gas temperature in the flue pipe ................................................................................................... 16

4.8.4 Flue gas temperature in the connecting pipe..................................................................................... 17

4.8.5 Flue gas temperature at chimney entrance mean flue gas temperature of the

chimney and temperature of the chimney wall at the top of the chimney .............................. 17

4.9 Calculation of flow mechanics ................................................................................................................. 17

4.9.1 General ............................................................................................................................................................. 17

4.9.2 Calculation of the standing pressure .................................................................................................... 17

4.9.3 Calculation of the flow velocity ............................................................................................................... 18

4.9.4 Calculation of the static friction .............................................................................................................. 18

4.9.5 Calculation of the resistance due to direction change .................................................................... 19

4.10 Operation control ......................................................................................................................................... 21

4.10.1 Pressure condition ...................................................................................................................................... 21

4.10.2 Dew point condition .................................................................................................................................... 21

4.10.3 Efficiency of the combustion η ................................................................................................................. 21

4.10.4 Flue gas triple of variates .......................................................................................................................... 22

Bibliography ................................................................................................................................................................. 23

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oSIST prEN 15544:2021
prEN 15544:2021 (E)
European foreword

This document (prEN 15544:2021) has been prepared by Technical Committee CEN/TC 295 “Residential

solid fuel burning appliances”, the secretariat of which is held by BSI.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 15544:2009.
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oSIST prEN 15544:2021
prEN 15544:2021 (E)
Introduction

This document specifies a calculation method for the dimensioning of Kachelgrundöfen/Putzgrundöfen

(tiled/mortared stoves).

The application of the calculations of this document enables a verification of the emission values carbon

monoxide, nitrogen dioxide, organically bound carbon as well as dust and the efficiency.

Complying with the calculations of this document results in emission values less or equal for carbon

3 3

monoxide 1 500 mg/m (1 000 mg/MJ), nitrogen dioxide 225 mg/m (150 mg/MJ), organically bound

n n
3 3

carbon 120 mg/m (80 mg/MJ) and dust 90 mg/m (60 mg/MJ). If the calculations of this document are

n n

used in combination with suitable combustion chambers that prove lower emission values in a type test,

these values are also considered to be complied with.

This calculation method for the dimensioning of Kachelgrundöfen/Putzgrundöfen (tiled/mortared

stoves) is based on appropriate literature as well as EN 13384-1, and where empirically determined

correlations are used in addition to physical and chemical formulas.

In case of a calculation method for different interior materials than fireclay the proof of the compliance

of the emission values and the efficiency should be delivered separately. Also, the empiric data of the

combustion chamber dimensions, the minimum flue pipe length, the burning rate as well as the

combustion chamber temperature and the decrease of the temperature along the flue pipe should also be

separately determined.
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oSIST prEN 15544:2021
prEN 15544:2021 (E)
1 Scope

This document specifies calculations for the dimensioning of Kachelgrundöfen/Putzgrundöfen

(tiled/mortared stoves) based upon the required nominal heat output of the stove as declared by the

producer. The Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) are of individual one-off

construction design. The document can be used for log wood fired Kachelöfen (tiled stoves) that burn one

fuel load per storage period with a maximum load between 10 kg and 40 kg (log wood with water content

from 12 % to 20 %, thickness of 5 cm to 10 cm in diameter, length varies usually from 25 cm to 50 cm,

and is oriented toward the combustion chamber dimensions) and a storage period (nominal heating

time) between 8 h and 24 h.

This document is valid for Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) equipped with

3 3

fireclay as interior material, with an apparent density between 1,750 kg/m and 2,300 kg/m , a degree

of porosity from 17 % up to 33 % by volume and a heat conductivity from 0,90 W/mK up to 1,30 W/mK

(temperature range 20 °C to 400 °C).

This document is valid for Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) with combustion air

supply from the side via a heating door frame or the standing grate of the heating door into the

combustion chamber. The document is valid for an inflow speed of the combustion air between 2 m/s

and 4 m/s.

This document also applies to the combination with combustion chambers that are suitable for one-off

Kachelgrundöfen/Putzgrundöfen (tiled/mortared stoves) and for which compliance with the legally

required emission values has been verified as part of a type test by an accredited and/or notified body.

This document is applicable to combustion chambers:
• with an air-fuel ratio of between 1,95 and 3,95 according to the type test;
• with a maximum fuel less than 10 kg, but more than 5 kg;
• using other suitable materials as well as fireclay.

With regard to the type test, this document is applicable combustion chambers which are:

• from slow heat release appliances tested according to EN 15250 (or prEN 16510-2-5);

• inserts tested according to EN 13229 (or prEN 16510-2-2); or

• combustion chambers tested according to respective national standards (e.g. ÖNORM B 8303).

This document applies to type tested combustion chambers designed for batch fired pellet burning if

meeting the requirements according to this document (air-fuel ratio between 1.95 and 3,95, the load of

the pellets shall be burned in 78 ± 20 min).

This document is not valid for combinations with water heat exchangers for central heating or other heat

absorbing elements like open water tanks and glass plates greater than 1/5 of the combustion chamber

surface, etc. This document is not valid for mass-produced prefabricated stoves (slow heat release

appliances) or partly prefabricated stoves (slow heat release appliances) according to EN 15250.

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oSIST prEN 15544:2021
prEN 15544:2021 (E)
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 13384-1, Chimneys – Thermal and fluid dynamic calculation methods – Part 1: Chimneys serving one

heating combustion
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
air-fuel ratio

ratio between the amount of air supplied to the combustion and the theoretically required amount of air

3.2
calculated flue pipe length
length which is required to determine the flue gas temperatures in the flue pipe
3.3
construction with air gap
construction, with an air gap between the inner and the outer shell

Note 1 to entry: It is a construction with an air gap if the distance between the inner and outer shell is at least

2,5 cm and more than 50 % of the Kachelgrundofen/Putzgrundofen (tiled/mortared stove) is built in this way.3.4

3.4
construction without air gap
construction, with no air gap between the inner and the outer shell

Note 1 to entry: It is a construction with no air gap if the distance between the inner and outer shell is less than

2,5 cm and at least 50 % of the Kachelgrundofen/Putzgrundofen (tiled/mortared stove) is built in this way.

3.5
combustion chamber base

area of a horizontal cut through the combustion chamber at the height of the lower edge of the firebox

opening
3.6
combustion chamber height

mean vertical distance between the combustion chamber base and the combustion chamber ceiling

3.7
combustion chamber surface
sum of the inner surfaces of the combustion chamber
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oSIST prEN 15544:2021
prEN 15544:2021 (E)
3.8
mean combustion chamber temperature
value to calculate the thermal lift in the combustion chamber
3.9
burning rate
mean fuel load divided by burning time
3.10
combustion chamber admeasurement
admeasurement of the combustion chamber base
3.11
gas groove
additional opening for the conduction of the flue gas
3.12
flue pipe length

length of the connecting line of all geometric centres of the flue pipe profiles from the combustion

chamber exit to the connecting pipe entrance
3.13
Kachelgrundofen
tiled stove
Kachelofen

one off slow heat release appliance, which is adapted individually to local conditions and whose visible

surface is predominantly made of tiles
3.14
short flue pipe section

section of the flue pipe, where the length of the section is shorter than the hydraulic diameter

3.15
minimum flue pipe length
Zmin
minimal acceptable length of the flue pipe
3.16
maximum load
load of the fuel at nominal heat output
3.17
minimum load
Bmin
load of the fuel at the lowest reduced heat output
3.18
nominal heat output
mean useable heat output of the heating appliance
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oSIST prEN 15544:2021
prEN 15544:2021 (E)
3.19
Putzgrundofen
mortared stove
Putzofen

one off slow heat release appliance, which is adapted individually to local conditions and whose visible

surface is predominantly plastered
3.20
storage period
nominal heating time

period of time specified by the producer where the nominal heat output is set free

3.21
efficiency

proportion (in percent) of the nominal heat output multiplied with the storage period to the total heat

input
4 Calculations
4.1 Nominal heat output

The nominal heat output (P of the stove shall be specified by the manufacturer so that the values of the

stove can be calculated according to 4.2 to 4.10. When specified to heat a full house or building unit, the

nominal heat output (Pn) shall correspond to the design heating load of the room or rooms to be heated.

In the case of partial heating, in which only part of the design heating load of the installation room is

covered, the nominal heat output (Pn) can be selected lower.
4.2 Load of fuel
4.2.1 Maximum load

The maximum load shall be at least 5 kg of fuel and shall be calculated as follows:

P⋅t
n n
m = (1)
min
⋅4.16
100
NOTE 1 To calculate, a net calorific value of wood of 4,16 kWh*kg is presumed.
where
m is the maximum load (kg);
P is the specified nominal heat output (kW);
t is the specified storage period (h);
η required minimum efficiency in %.
min
NOTE 2 The storage period can vary between 8 h and 24 h.

If tested combustion chambers are used, the maximum load at nominal heat output shall be the maximum

fuel mass according to the type test.
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oSIST prEN 15544:2021
prEN 15544:2021 (E)
4.2.2 Minimum load

The definition and calculation of the minimum load is only necessary if a reduced heat output is declared

by the manufacturer. The minimum load shall be calculated as 50 % of the maximum load as follows:

mm0.5⋅ (2)
Bmin B
where
m is the maximum load (kg);
m is the minimum load (kg).
Bmin

If tested combustion chambers are used, the minimum load at reduced heat output shall be the minimum

fuel mass according to the type test. The share can deviate from the 50 % according to Formula (2).

4.3 Design of the essential dimensions
4.3.1 Combustion chamber dimensions
4.3.1.1 General

The height of the lowest opening shall be at least 5 cm above the floor of the combustion chamber.

NOTE Designing the dimensions of the combustion chamber serves two main purposes: firstly to ensure that

sufficient room is available to contain the fuel needed to be charged and secondly that the requirements for clean

combustion are met. Clause 4.3.1 does not apply to tested combustion chambers.
4.3.1.2 Combustion chamber surface
The dimension of the combustion chamber surface shall be calculated as follows:
O 900×m (3)
BR B
where
m is the maximum load (in kg);
O is the combustion chamber surface (in cm ).

For the calculation of the combustion chamber surface all its walls, the ceiling and the base including the

area of the combustion chamber opening and the combustion chamber exit for the flue gas shall be

regarded equally i.e. calculated as if there were no combustion openings or exits.

4.3.1.3 Combustion chamber base
The combustion chamber base can be varied between a minimum and a maximum value.
The minimum value results from the requirement that at maxi
...

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