IEC 62282-3-202:2025

Fuel cell technologies - Part 3-202: Stationary fuel cell power systems - Performance test methods for small fuel cell power systems for multiple units operation

IEC 62282-3-202:2025 provides performance test methods specialized for the thermal and electrical characteristics of an energy management system to effectively share the heat and power of networked small stationary fuel cell power systems. These test methods are applied for each small stationary fuel cell power system. This document covers small stationary fuel cell power systems which can be complemented with a supplementary heat generator or a thermal storage system, or both, such as:
- output: rated electric power output of less than 10 kW for each system;
- output mode: grid-connected or independent operation or stand-alone operation with alternating current (AC) output not exceeding 240 V or direct current (DC) output;
- operating pressure: maximum allowable working pressure of less than 0,1 MPa (G) for the fuel and oxidant passages;
- fuel: gaseous fuel (natural gas, liquefied petroleum gas, propane, butane, hydrogen) or liquid fuel (kerosene, methanol); oxidant: air.
This document does not apply to small stationary fuel cell power systems with electricity storage other than (small scale) back-up power for safety, monitoring and control.

Technologies des piles à combustible - Partie 3-202: Systèmes à piles à combustible stationnaires - Méthodes d'essai des performances pour petits systèmes à piles à combustible destinés à l'exploitation d'unités multiples

l’IEC 622823-202:2025 fournit des méthodes d’essai des performances spécialisées pour les caractéristiques thermiques et électriques d’un système de gestion de l’énergie pour partager efficacement la chaleur et l’électricité des petits systèmes à piles à combustible stationnaires en réseau. Ces méthodes d’essai s’appliquent à chaque petit système à pile à combustible stationnaire. Le présent document couvre les petits systèmes à piles à combustible stationnaires qui peuvent être complétés par un générateur de chaleur
- supplémentaire ou un système de stockage thermique, ou les deux, tel que:
- puissance de sortie: puissance électrique de sortie assignée inférieure à 10 kW pour chaque système;
- mode de sortie: fonctionnement connecté au réseau ou indépendamment du réseau ou fonctionnement autonome avec sortie en courant alternatif ne dépassant pas 240 V ou sortie en courant continu;
- pression de fonctionnement: pression de fonctionnement admissible maximale inférieure à 0,1 MPa (G) pour les passages du combustible et de l’agent oxydant;
- combustible: gazeux (gaz naturel, gaz de pétrole liquéfié, propane, butane, hydrogène) ou liquide (kérosène, méthanol);
agent oxydant: air.
Le présent document ne s’applique pas aux petits systèmes à piles à combustible stationnaires avec un stockage d’énergie électrique autre qu’une alimentation de secours (à petite échelle) à des fins de sécurité, de surveillance et de contrôle.

General Information

• Status: Published
• Publication Date: 26-Mar-2025
• ICS: 27.070 - Fuel cells
• Technical Committee: TC 105 - Fuel cell technologies
• Drafting Committee: WG 212 - TC 105/WG 212
• Current Stage: PPUB - Publication issued
• Start Date: 27-Mar-2025
• Completion Date: 28-Mar-2025

Overview

IEC 62282-3-202:2025 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies performance test methods for small stationary fuel cell power systems operated in multiple unit configurations. Focused on systems with rated electric power output below 10 kW, this standard addresses the thermal and electrical characteristics of energy management systems designed to efficiently share heat and power across a network of small fuel cell units. It applies to stationary fuel cells powered by various gaseous and liquid fuels, used under grid-connected, independent, or stand-alone modes with defined voltage limits.

This standard establishes consistent testing methods to verify system performance, including start-up and shut-down energy, ramp rates, heat recovery efficiency, and thermal storage properties. It excludes systems with electricity storage except for limited backup power functionalities. IEC 62282-3-202:2025 supports manufacturers, system integrators, and testing laboratories to conduct robust and repeatable assessments critical for advancing the adoption of fuel cell technologies in decentralized power applications.

Key Topics

• Scope and Application: Small stationary fuel cell systems below 10 kW output, including those paired with supplementary heat generators or thermal storage.
• Electric Performance Testing:
  • Power generation electrical efficiency at rated and partial loads.
  • Measurement of start-up and shut-down energy requirements.
  • Ramp-up and ramp-down rates between minimum and rated loads.
  • Hot restart waiting times for system reliability assessment.
• Thermal Performance Testing:
  • Heat recovery efficiency measurements.
  • Determination of hot water tank heat storage capacity and insulation performance.
  • Heat recovery temperature and pressure drop characteristics in the thermal circuit.
• Testing Conditions and Setup:
  • Standardized laboratory and operating conditions.
  • Fuel quality and composition guidelines.
  • Specific instrumentation and measurement point requirements with uncertainty analysis.
• Reporting Guidelines:
  • Format and content for summary, detailed, and full test reports.
• Fuel and Operating Parameters:
  • Use of natural gas, LPG, propane, butane, hydrogen, kerosene, and methanol as fuel sources.
  • Maximum allowable operating pressures of less than 0.1 MPa (gauge).
  • AC output not exceeding 240 V or DC output limits.

Applications

IEC 62282-3-202:2025 is essential for:

• Manufacturers and Developers: To validate the performance and reliability of small fuel cell power systems intended for residential, commercial, or small industrial stationary applications.
• Certification and Testing Laboratories: Providing harmonized test procedures that ensure replicable and internationally consistent assessments.
• System Integrators: Evaluating combined heat and power performance in multiple, networked small fuel cell units to optimize energy sharing and system management.
• Energy Managers and Utility Providers: Utilizing test data to support grid-connected or off-grid power solutions with small fuel cells, improving energy efficiency and sustainability.
• Research Institutions: Supporting experimental validation and performance benchmarking of emerging stationary fuel cell technologies under realistic operating conditions.

This standard contributes to the broader adoption of fuel cell technologies as distributed energy resources, enabling clean and efficient decentralized power and heat generation and enhancing energy system resilience.

Related Standards

• IEC 62282 Series: Covers various aspects of fuel cell technologies including terminology, safety, performance, and test methods across different fuel cell types and applications.
• ISO 20340: For performance evaluation of power generation systems, often complementary in setting comprehensive test regimes.
• IEC 60068: Environmental testing methods relevant for simulating operational conditions.
• ISO 17691: Guidance on energy efficiency testing in stationary power systems.
• Safety and Electrical Standards: National or regional electrical installation standards ensuring compliant system integration.

Incorporating IEC 62282-3-202:2025 within quality assurance and testing frameworks ensures small stationary fuel cell power systems are assessed against internationally recognized benchmarks, fostering confidence among manufacturers, consumers, and regulators. This helps accelerate the commercialization and deployment of sustainable fuel cell systems worldwide.

Standards Content (Sample)

IEC 62282-3-202 ®
Edition 1.0 2025-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fuel cell technologies –
Part 3-202: Stationary fuel cell power systems – Performance test methods for
small fuel cell power systems for multiple units operation

Technologies des piles à combustible –
Partie 3-202: Systèmes à piles à combustible stationnaires – Méthodes d'essai
des performances pour petits systèmes à piles à combustible destinés à
l'exploitation d'unités multiples
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IEC 62282-3-202 ®
Edition 1.0 2025-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Fuel cell technologies –
Part 3-202: Stationary fuel cell power systems – Performance test methods for

small fuel cell power systems for multiple units operation

Technologies des piles à combustible –

Partie 3-202: Systèmes à piles à combustible stationnaires – Méthodes d'essai

des performances pour petits systèmes à piles à combustible destinés à

l'exploitation d'unités multiples

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.070  ISBN 978-2-8327-0298-7

– 2 – IEC 62282-3-202:2025 © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Symbols . 12
5 Configuration of small stationary fuel cell power system . 14
6 Reference conditions . 15
7 Heating value base . 15
8 Test preparation . 15
8.1 General . 15
8.2 Uncertainty analysis . 16
8.3 Data acquisition plan . 16
9 Test set-up . 16
10 Instruments and measurement methods . 18
10.1 General . 18
10.2 Measurement instruments . 18
10.3 Measurement points. 19
10.4 Minimum required measurement systematic tolerance . 20
11 Test conditions . 21
11.1 Laboratory conditions. 21
11.2 Installation and operating conditions of the system . 21
11.3 Test fuel . 21
12 Parameter list . 21
12.1 Electrical characteristics for fuel cell power system . 21
12.1.1 Power generation electrical efficiency (rated, partial load) . 21
12.1.2 Start-up, shut-down energy . 21
12.1.3 Ramp-up rate and ramp-down rate between rated and minimum load . 21
12.1.4 Waiting time for restart (hot restart) . 21
12.2 Thermal characteristics for fuel cell power system . 21
12.2.1 Heat recovery efficiency . 21
12.2.2 Full heat storage amount of hot water tank . 21
12.2.3 Remaining hot storage amount of hot water tank . 22
12.2.4 Heat insulating performance of hot water tank . 22
12.2.5 Heat recovery temperature . 22
12.2.6 Pressure drop characteristics from feed water inlet to hot water outlet . 22
13 Test methods . 22
13.1 Electrical characteristics for fuel cell power system . 22
13.1.1 Power generation electrical efficiency (rated, partial load) . 22
13.1.2 Start-up, shut-down energy . 27
13.1.3 Ramp-up rate and ramp-down rate between rated and minimum load . 30
13.1.4 Waiting time for restart (hot restart) . 35
13.2 Thermal characteristics for fuel cell power system . 35
13.2.1 Heat recovery test . 35
13.2.2 Full heat storage amount of hot water tank . 37

13.2.3 Remaining heat storage amount of hot water tank . 38
13.2.4 Heat insulating performance of hot water tank . 39
13.2.5 Heat recovery temperature . 39
13.2.6 Pressure drop characteristics from feed water inlet to hot water outlet . 40
14 Test reports . 40
14.1 General . 40
14.2 Title page. 40
14.3 Table of contents . 40
14.4 Summary report . 41
Annex A (informative) Heating values for components of natural gases . 42
Annex B (informative) Examples of nominal composition for natural gas and propane
gas . 44
Annex C (informative) Guidelines for the contents of detailed and full reports . 47
C.1 General . 47
C.2 Detailed report . 47
C.3 Full report . 47
Annex D (informative) Pressure drop characteristics from feed water inlet to hot water
outlet . 48
Bibliography . 49

Figure 1 – Configuration of a fuel cell power system that can be complemented with a

supplementary heat generator or thermal storage system covered by this document . 14
Figure 2 – Test set-up for small stationary fuel cell power system fed with gaseous fuel
which supplies electricity and useful heat. 17
Figure 3 – Test set-up for small stationary fuel cell power system fed with gaseous fuel
which supplies only electricity . 18
Figure 4 – Example of electric power chart during start-up time . 27
Figure 5 – Example of liquid fuel supply systems . 28
Figure 6 – Electric power chart during shutdown time . 29
Figure 7 – Electric power output change pattern for ramp-up and ramp-down rate test . 32
Figure 8 – Example for electric power change stabilization criteria . 33
Figure 9 – Explanation of temperature sensor locations and V . 38
j
Figure D.1 – Example for the pressure drop characteristics from feed water inlet to hot

water outlet . 48

Table 1 – Symbols and their meanings for electric and thermal performance . 12
Table A.1 – Heating values for components of natural gases at various combustion
reference conditions for ideal gas . 42
Table B.1 – Examples of composition of natural gas (%) . 45
Table B.2 – Examples of composition of propane gas (%) . 46

– 4 – IEC 62282-3-202:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
FUEL CELL TECHNOLOGIES –
Part 3-202: Stationary fuel cell power systems – Performance test
methods for small fuel cell power systems for multiple units operation

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
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shall not be held responsible for identifying any or all such patent rights.
IEC 62282-3-202 has been prepared by IEC technical committee 105: Fuel cell technologies. It
is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
105/1094/FDIS 105/1101/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62282 series, published under the general title Fuel cell technologies,
can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 62282-3-202:2025 © IEC 2025
INTRODUCTION
This part of IEC 62282 provides consistent and repeatable test methods for the electrical
thermal and environmental performance of small stationary fuel cell power systems.
This document limits its scope to small stationary fuel cell power systems (electric power output
below 10 kW) and provides test methods specifically designed for them in detail. It is based on
IEC 62282-3-201.
For multiple units operation, each electric power output of the unit is limited to below 10 kW.
This document is intended for manufacturers of small stationary fuel cell power systems or
those who evaluate the performance of their systems for certification purposes.
Users of this document can selectively execute test items that are suitable for their purposes
from those described in this document. This document is not intended to exclude any other
methods.
This document describes type tests and their test methods only. In this document, no routine
tests are required or identified, and no performance targets are set.

FUEL CELL TECHNOLOGIES –
Part 3-202: Stationary fuel cell power systems – Performance test
methods for small fuel cell power systems for multiple units operation

1 Scope
This part of IEC 62282 provides performance test methods specialized for the thermal and
electrical characteristics of an energy management system to effectively share the heat and
power of networked small stationary fuel cell power systems. These test methods are applied
for each small stationary fuel cell power system. This document covers small stationary fuel
cell power systems which can be complemented with a supplementary heat generator or a
thermal storage system, or both, such as:
– output: rated electric power output of less than 10 kW for each system;
– output mode: grid-connected or independent operation or stand-alone operation with
alternating current (AC) output not exceeding 240 V or direct current (DC) output;
– operating pressure: maximum allowable working pressure of less than 0,1 MPa (G) for the
fuel and oxidant passages;
– fuel: gaseous fuel (natural gas, liquefied petroleum gas, propane, butane, hydrogen) or
liquid fuel (kerosene, methanol);
– oxidant: air.
This document does not apply to small stationary fuel cell power systems with electricity storage
other than (small scale) back-up power for safety, monitoring and control.
NOTE Regarding data linkage for conducting the performance tests specified in this document with operating
management systems (energy management system) of multiple fuel cell power systems (mFCPS), an appropriate
IEC standard can be selected and implemented. The related standards are IEC 61850-7-420, IEC TR 61850-90-27,
IEC 62394, IEC 62746-10-1, IEC 62746-10-3, etc. The data linkage and implementation for realizing the functions of
the system that monitors mFCPS and peripherals differ depending on the vendor of the mFCPS control system, so
the methods for data linkage and implementation are not specified in this document.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
cold state
state of a fuel cell power system, which is entirely at ambient temperature with no power input
or output, ready for start-up
[SOURCE: IEC 60050-485:2020, 485-21-01, modified – "ready for start-up" added.]

– 8 – IEC 62282-3-202:2025 © IEC 2025
3.2
electrical efficiency
ratio of the average net electric power output produced by a fuel cell power system to the
average fuel power input supplied to the fuel cell power system
Note 1 to entry: The lower heating value (LHV) is assumed unless otherwise stated
[SOURCE: IEC 60050-485:2020, 485-10-02, modified – "electrical" instead of "electric" in the
term; "average net electric power output" instead of "net electric power"; "average fuel power
input" instead of "total enthalpy flow".]
3.3
electric energy input
integrated value of electric power input at the electric input terminal
[SOURCE: IEC 62282-3-201:2025, 3.8]
3.4
electric energy output
integrated value of electric power output at the electric output terminal
[SOURCE: IEC 62282-3-201:2025, 3.9]
3.5
electric power input
electric power input at the electric input terminal of the fuel cell power system
[SOURCE: IEC 62282-3-201:2025, 3.10]
3.6
electric power output
electric power output at the electric output terminal of the fuel cell power system
[SOURCE: IEC 62282-3-201:2025, 3.11]
3.7
fuel cell power system
generator system that uses one or more fuel cell modules to generate electric power and heat
[SOURCE: IEC 60050-485:2020, 485-09-01]
3.8
fuel input
amount of natural gas, hydrogen, methanol, liquid petroleum gas, propane, butane, or other
material containing chemical energy entering the fuel cell power system while it is working at
the specified operating conditions
[SOURCE: IEC 62282-3-201:2025, 3.13]
3.9
fuel power input
fuel energy input per unit of time
[SOURCE: IEC 62282-3-201:2025, 3.14]

3.10
heat recovery efficiency
ratio of the average recovered thermal power output of a fuel cell power system to the average
total power input supplied to the fuel cell power system
[SOURCE: IEC 60050-485:2020, 485-10-04, modified – "the average recovered thermal power
output" instead of "recovered heat flow"; "average total power input" instead of "total enthalpy
flow"; Note 1 to entry deleted.]
3.11
heat recovery fluid
fluid circulating between the fuel cell power system and a heat sink for recovering the thermal
energy output
[SOURCE: IEC 62282-3-201:2025, 3.16]
3.12
hot restart
start operation of the fuel cell power system before the power system temperature condition
reaches the "cold state"
3.13
inert purge gas
inert gas or dilution gas, not containing chemical energy, supplied to the fuel cell power system
during specific conditions to make it ready for operation or shutdown
Note 1 to entry: Dilution gas containing chemical energy shall be considered as fuel.
[SOURCE: IEC 62282-3-201:2025, 3.17]
3.14
integrated fuel input
volume or mass of fuel consumed by the fuel cell power system under specified operating
conditions
[SOURCE: IEC 62282-3-201:2025, 3.18]
3.15
interface point
measurement point at the boundary of a fuel cell power system at which material or energy, or
both, either enters or leaves
Note 1 to entry: This boundary is intentionally selected to accurately measure the performance of the system,
including all normal operation, both steady state and transient. If necessary, the boundary or the interface points of
the fuel cell power system (Figure 1) to be assessed should be determined by agreement between the parties.
Note 2 to entry: Typical conditions to be standardized refer to fuel and oxidant parameters, like compositions, flow
rates, temperature, pressure and humidity, as well as to the fuel cell parameters, like temperature.
[SOURCE: IEC 60050-485:2020, 485-09-12, modified – reference to Figure 1 added.]
3.16
minimum electric power output
minimum net power output, at which a fuel cell power system is able to operate continuously at
a steady state
[SOURCE: IEC 62282-3-201:2025, 3.21]

– 10 – IEC 62282-3-202:2025 © IEC 2025
3.17
net electric power output
power generated by the fuel cell power system and available for external use
[SOURCE: IEC 60050-485:2020, 485-14-03, modified – "output" added to the term, Notes 1 and
2 to entry deleted.]
3.18
rated electric power output
maximum continuous electric power output that a fuel cell power system is designed to achieve
under normal operating conditions specified by the manufacturer
[SOURCE: IEC 60050-485:2020, 485-14-04, modified – "electric" and "output" added to the
term, Note 1 to entry deleted.]
3.19
ramp-up time
duration required for transitioning from zero or minimum net electric power output to rated net
electric power output
[SOURCE: IEC 62282-3-201:2025, 3.29, modified – "zero or minimum" instead of "positive";
"after start-up" deleted.]
3.20
ramp-down time
duration required for transitioning from rated net electric power output to minimum or zero net
electric power output
3.21
recovered heat
thermal energy that has been recovered for useful purpose
Note 1 to entry: The recovered heat is measured by determining the temperatures and flow rates of the heat recovery
fluid (water, steam, air or oil, etc.) entering and leaving the thermal energy recovery subsystem at the interface point
of the fuel cell power system.
[SOURCE: IEC 62282-3-201:2025, 3.30]
3.22
recovered thermal power
recovered heat per unit of time
[SOURCE: IEC 62282-3-201:2025, 3.31]
3.23
shutdown energy
sum of electric or chemical (fuel) energy, or both required during the shutdown time
[SOURCE: IEC 62282-3-201:2025, 3.32]

3.24
shutdown time
duration between the instant when a shutdown action is initiated at rated electric power output
and the instant when the cold state or storage state, as specified by the manufacturer, is
attained
[SOURCE: IEC 60050-485:2020, 485-20-04, modified – "a shutdown action is initiated at rated
electric power output" instead of "the load is removed"; "the cold state or storage state, as
specified by the manufacturer, is attained" instead of "the shutdown is completed".]
3.25
start-up energy
sum of the electric, thermal, mechanical and chemical (fuel) energy required by a fuel cell power
system for transitioning from cold state or storage state to positive net electric power output
[SOURCE: IEC 60050-485:2020, 485-18-05, modified – "for transitioning from cold state or
storage state to positive net electric power output" instead of "during the start-up time".]
3.26
start-up time

duration required for transitioning from cold state to positive net electric power output
[SOURCE: IEC 60050-485:2020, 485-20-05, modified – "positive" added.]
3.27
start-up time
duration
required for transitioning from storage state to positive net electric power output
[SOURCE: IEC 60050-485:2020, 485-20-06, modified – "positive" added.]
3.28
stationary fuel cell power system
fuel cell power system that is connected and fixed in place
[SOURCE: IEC 60050-485:2020, 485-09-24, modified – the figure has been omitted.]
3.29
storage state
state of a fuel cell power system being non-operational and possibly requiring, under conditions
specified by the manufacturer, the input of thermal energy, electric energy or an inert
atmosphere, or any combination thereof, in order to prevent deterioration of the components or
energize the control systems and other components, or both and is ready for start-up
[SOURCE: IEC 60050-485:2020, 485-21-06, modified – "or energize the control systems and
other components, or both and is ready for start-up" added.]
3.30
thermal storage unit
unit that stores heat recovered from the fuel cell power system in the thermal storage medium
and supplies the heat with heat carrier externally as needed
Note 1 to entry: It is composed of a thermal storage tank, a heat exchanger and a heat carrier supply system.
Note 2 to entry: A typical thermal storage medium is water.
[SOURCE: IEC 62282-3-201:2025, 3.39]

– 12 – IEC 62282-3-202:2025 © IEC 2025
4 Symbols
The symbols and their meanings used in this document are given in Table 1 with the appropriate
units.
Table 1 – Symbols and their meanings for electric and thermal performance
Symbol Definition Unit
c Specific heat
c
Specific heat capacity of heat recovery fluid kJ/(kg·K)
HR
c
Specific heat of water at the temperature T
kJ/(kg·K)
pj Vj
E Energy
E
Energy input of gaseous fuel per unit mass kJ/kg
mf
E
Energy input of the fuel per unit volume
kJ/m
Vf
E Fuel energy input
kJ
fin
H Heating value
H
Heating value of fuel on a molar basis under reference conditions kJ/mol
f0
H Heating value of component j at reference temperature T
kJ/mol
f0j 0
H
Heating value of liquid fuel kJ/kg
fl
M Molar mass
M
Molar mass of fuel kg/mol
f
m Mass
m Fuel mass measured over the test duration kg
f
m
Heat recovery fluid mass kg
HR
P, dP Power, power change rate
P
Average net electric power output
kW
n
P Rated electric power output
kW
rated
P Minimum electric power output
kW
min
P Electric power output change range between P and P
kW
d rated min
P
Average recovered thermal power kJ/s
HR
P Average fuel power input
kJ/s
fin
dP Decrease rate of electric power output
kW/s
downi
dP Increase rate of electric power output
kW/s
upi
p Pressure
p Reference pressure (101,325 kPa (abs))
kPa (abs)
p
Average fuel pressure
kPa (abs)
f
Q Amount of heat
Q Storage heat amount of the hot water tank kJ
full
Q Remaining heat storage amount of the hot water tank kJ
remaining
∆Q Heat loss of the hot water tank kJ/h
loss
Q Initial heat storage amount of the hot water tank kJ
init
Q
Heat storage amount of the hot water tank after 10 h of heat loss kJ
10h
Symbol Definition Unit
q
Mass flow rate
m
q Average mass flow rate of fuel
kg/s
mf
q
Average mass flow rate of heat recovery fluid kg/s
mHR
q
Volumetric flow rate
V
q
Average volumetric flow rate of fuel under the test conditions
m /s
Vf
q Average volumetric flow rate of fuel under reference conditions
m /s
Vf0
q Average volumetric flow rate of heat recovery fluid
m /s
VHR
T Temperature
T Reference temperature (288,15 K)
K
T Average fuel temperature
K
f
T
Average temperature of heat recovery fluid output K
HR1
T
Average temperature of heat recovery fluid input K
HR2
T Average temperature of the temperatures measured by sensor j-1 and sensor j
K
Vj
T Feed water temperature
K
feed
t Time
∆t Test duration s
∆t Start-up time
s
st
t Start-up initiation time
st1
t Start-up completion time
st2
∆t Shutdown time
s
shut
t Shutdown initiation time
shut1
t Shutdown completion time
shut2
∆t Ramp-up time
s
ramp-upi
t
Ramp-up start time
ramp-upi-1
t Ramp-up completion time
ramp-upi-2
Ramp-down time
∆t
s
ramp-downi
t Ramp-down start time
ramp-downi-1
t Ramp-down completion time
ramp-downi-2
V Volume
V
Fuel volume measured over the test duration m
f
V
Heat recovery fluid volume
m
HR
V Water volume in the order of j divided part
L
j
V
Molar volume
m
−2 3 3
V
Reference molar volume of ideal gas (2,364 5 × 10 m /mol at reference m /mol
m
temperature T = 288,15 K and reference pressure p = 101,325 kPa)
0 0
W Electric energy
W
Electric energy output kW·h
out
W Electric energy input kW·h
in
W Electric energy input during start-up time kW·h
inst
– 14 – IEC 62282-3-202:2025 © IEC 2025
Symbol Definition Unit
W Electric energy input during shutdown time kW·h
inshut
W Electric energy output during ramp-up time kW·h
ramp-upi
W Electric energy output during ramp-down time kW·h
ramp-downi
x Molar ratio
x
Molar ratio of component j
j
η Efficiency
η Electrical efficiency %
el
η Heat recovery efficiency %
th
ρ Density
ρ Density of heat recovery fluid at T
kg/m
HR HR1
ρ Density of water at the temperature T kg/L
j Vj
5 Configuration of small stationary fuel cell power system
Figure 1 illustrates the general configuration of a small stationary fuel cell power system which
is the subject of this document and shows the system boundary and physical quantities entering
and leaving the fuel cell power system. The fuel cell power system can be complemented with
a supplementary heat generator, a thermal storage system or electricity from the grid.

NOTE This Figure 1 displays only the major interconnections between the subsystems.
Figure 1 – Configuration of a fuel cell power system that can be complemented with a
supplementary heat generator or thermal storage system covered by this document

6 Reference conditions
The reference conditions are specified as follows:
– reference temperature: T = 288,15 K (15 °C);
– reference pressure: p = 101,325 kPa (abs).
7 Heating value base
The heating value of fuel is based on the lower heating value (LHV) in principle.
In cases where the LHV is applied to the calculation of energy efficiency, it is not necessary to
add the symbol "LHV", as shown below:
η , η , or η = XX %
el th total
If the higher heating value (HHV) is applied, the abbreviation "HHV" shall be added to the value
of energy efficiency, as follows:
η , η , or η = XX % (HHV)
el th total
NOTE Heating values for components of fuel gases for both LHV and HHV are given in Table A.1.
8 Test preparation
8.1 General
Clause 8 describes typical items that shall be considered prior to the implementation of a test.
For each test, an effort shall be made to minimize uncertainty by selecting high-precision
instruments and planning the tests carefully with attention to detail. Detailed test plans shall be
prepared by the parties to the test using this document as their basis. A written test plan shall
be prepared.
The following items shall be considered for the test plan:
a) objective;
b) test specifications;
c) test personnel qualifications;
d) quality assurance standards (e.g. ISO 9000 or other equivalent standards);
e) target uncertainty;
f) identification of measurement instruments (refer to Clause 10);
g) estimated range of test parameters;
h) data acquisition plan.
– 16 – IEC 62282-3-202:2025 © IEC 2025
8.2 Uncertainty analysis
An uncertainty analysis shall be performed on the two test quantities (test output parameters)
below to indicate the reliability of the test results and to comply with customer requests. The
following test results shall be analysed to determine the absolute and relative uncertainty. A
test shall be planned so that the reliability of the results can be evaluated for the following:
– electrical efficiency;
– heat recovery efficiency;
NOTE 1 See also IEC 62282-3-200:2025, Annex A.
NOTE 2 For uncertainty of measurements, refer to ISO/IEC Guide 98-3.
8.3 Data acquisition plan
To meet the target uncertainty, proper duration and frequency of readings shall be defined and
suitable data recording equipment shall be prepared before the performance test.
Automatic data acquisition using a personal computer or similar device is preferable.
9 Test set-up
Figure 2 and Figure 3 illustrate examples of the test set-up that is required to conduct small
stationary fuel cell power system testing with gaseous fuel described in this document. In
Figure 2, an electric load and a thermal load are connected to a fuel cell power system. Figure 2
illustrates the measurement of electric characteristics and heat recovery characteristics of the
system. A thermal storage unit, which stores heat recovered from the fuel cell power system in
the thermal storage medium can be used as the thermal load. In Figure 3, only an electric load
is connected to the fuel cell power system. Figure 3 illustrates the measurement of electric
characteristics of the system.

Key
I
ammeter (optional)
V
voltmeter (optional)
T
thermometer
p
pressure gauge
q
flowmeter
F
integrating flowmeter
P
electric power meter
W
electric energy meter
RH
relative humidity meter
NOTE Measurement of current and voltage are optional and can replace power or energy measurements.
Figure 2 – Test set-up for small stationary fuel cell power system fed with gaseous fuel
which supplies electricity and useful heat

– 18 – IEC 62282-3-202:2025 © IEC 2025

Key
See key for Figure 2.
Figure 3 – Test set-up for small stationary fuel cell power system fed with gaseous fuel
which supplies only electricity
10 Instruments and measurement methods
10.1 General
Measurement instruments and measurement methods shall conform to the relevant
international standards. They shall be selected to meet the measurement range specified by
the manufacturer and the required accuracy of measurements.
10.2 Measurement instruments
Measurement instruments are listed according to their intended use:
a) apparatus for measuring the electric power output, electric power input, electric energy
input, and electric energy output:
– electric power meters, electric energy meters, voltmeters, ammeters;
b) apparatus for measuring fuel input:
– flowmeters, integrating flowmeters, scales, pressure sensors, temperature sensors;
c) apparatus for measuring fuel composition:
– gas chromatographs, mass spectrometers, absorption spectrometers;
d) apparatus for measuring the thermal energy output (only in cases of utilization of the heat):
– flowmeters, integrating flowmeters, temperature sensors;
e) apparatus for measuring ambient conditions:
– barometers, hygrometers, and temperature sensors.

10.3 Measurement points
Measurement points for different parameters are described below.
a) Gaseous fuel flow rate:
place a flowmeter for fuel on the fuel supply line to the fuel cell power system to measure
the fuel flow rate.
b) Gaseous integrated fuel input:
place an integrating flowmeter for fuel on the fuel supply line to the fuel cell power system
to measure the fuel input. The integrating flowmeter can combine a flowmeter that measures
the fuel flow rate.
c) Liquid fuel input mass:
place scales under the fuel tank or the entire system, including the fuel tank, to measure
the mass of fuel.
d) Fuel temperature:
connect a thermometer immediately downstream of the fuel flowmeter.
e) Fuel pressure:
place a pressure meter immediately downstream of the fuel flowmeter to measure the gauge
pressure of fuel.
f) Electric power output:
connect an electric power meter to the electric power output terminal of the fuel cell power
system and close to the system boundary.
g) Ele
...