ISO 13579-11:2017

INTERNATIONAL ISO
STANDARD 13579-11
First edition
2017-08
Industrial furnaces and associated
processing equipment — Method
of measuring energy balance and
calculating energy efficiency —
Part 11:
Evaluation of various kinds of
efficiency
Fours industriels et équipements associés — Méthode de mesure du
bilan énergétique et de calcul de l’efficacité —
Partie 11: Évaluation de différents types d’efficacité
Reference number
©
ISO 2017
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 4
5 Boundary and energy (enthalpy) . 7
5.1 Configuration of the area of evaluation . 7
5.2 Classification of boundary . . 7
5.3 Classification of energy (enthalpy) . 8
5.4 Calculation of energy (enthalpy) .11
5.4.1 Energy input to the heating chamber (E ) .11
h
5.4.2 Energy required for process (E ) .12
pr
5.4.3 Sensible heat of exhaust gas at the outlet of combustion chamber .12
5.4.4 Sensible heat of exhaust gas at the outlet of heat recovery equipment .13
5.4.5 Sensible heat of exhaust gas at the inlet of heat recovery equipment .13
5.4.6 Recovery heat (E ) .13
h,re
5.4.7 Thermal energy loss (E ) .14
l
5.4.8 Electrical energy loss in electroheating (E ).15
l,eh
5.4.9 Energy consumed in auxiliary equipment (E ) .15
aux
5.4.10 Energy consumed in generation of utilities (E ) .16
u,gen
5.4.11 Electrical generation loss (E ) .16
l,eg
5.4.12 Fuel equivalent energy of electricity (E ) .16
fe,el
5.4.13 Recycled energy (E ) .16
rcy
6 Efficiency based on enthalpy .16
6.1 General formula .16
6.2 Examples of typical efficiencies .16
6.2.1 General.16
6.2.2 Overall efficiency in accordance with ISO 13579‑1 .17
6.2.3 Heat efficiency on the whole calorific value basis .17
6.2.4 Heat efficiency on the supplied calorific value basis .17
6.2.5 Available heat ratio .17
6.2.6 Combustion efficiency .17
6.2.7 Effective waste heat recovery ratio in combustion furnace .18
6.2.8 Waste heat recovery ratio as performance indicator of heat
recovery equipment .18
6.2.9 Ratio of waste heat of combustion exhaust gas to calorific value of fuel .18
6.2.10 Converted available heat ratio where waste heat recovery is not considered .18
7 Efficiency based on exergy .18
7.1 General .18
7.2 Boundary .18
7.3 Classification of exergy .18
7.4 Calculation of exergy .19
7.4.1 Exergy input from electrical source (EX ) .19
h,el
7.4.2 Exergy of fuel (EX ) .20
h,fuel
7.4.3 Exergy of exothermic reaction (EX ) .20
react,exo
7.4.4 Exergy of sensible heat of fluid at the inlet (EX ) .20
s,fluid
7.4.5 Exergy in energy required for drying and evaporation (EX ).21
pr,ev
7.4.6 Exergy required for endothermic reaction for heated material (EX ) .21
pr,re
7.4.7 Exergy in given enthalpy to product (EX ) .21
pr,en
7.4.8 Exergy of exhaust gas (EX EX , EX ) .21
ex,oc, ex,or ex,ir
7.4.9 Recovery exergy (EX ) .22
h,re
7.4.10 Exergy in required for heating jigs and other substance (EX ) .22
l,j
7.4.11 Exergy in heat loss from furnace structure (EX ) .22
l,fs
7.4.12 Exergy in energy required for heat storage of furnace structure (EX ) .22
l,hs
7.4.13 Exergy in given enthalpy to atmosphere gas (EX ) .22
l,atm
7.4.14 Exergy consumed in electroheating (EX ) .22
l,eh
7.4.15 Exergy consumed in auxiliary equipment (EX ) .23
aux
7.4.16 Exergy consumed in generation of utilities (EX ) .23
u,gen
7.4.17 Exergy of recycled energy (EX ) .23
rcy
7.5 Efficiency .23
7.5.1 General formula .23
7.5.2 Examples of typical efficiencies .23
8 Designation .24
8.1 General .24
8.2 Individual item block .25
8.3 Type of operation .25
8.4 Energy source .25
8.5 Example .25
9 Measurement .26
10 Evaluation report .26
Annex A (informative) Example of energy efficiency evaluation .27
Annex B (informative) Comparison of enthalpy efficiency and exergy efficiency of
continuous reheating furnaces .37
Annex C (informative) Procedure for estimation of energy saving effect of combustion furnaces .46
Bibliography .60
iv © ISO 2017 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should b
...