ISO 5222-2:2025

International
Standard
ISO 5222-2
First edition
Heat recovery ventilators and
2025-02
energy recovery ventilators —
Testing and calculating methods for
seasonal performance factor —
Part 2:
Sensible cooling recovery seasonal
performance factors of heat
recovery ventilators (HRV)
Ventilateurs récupérateurs de chaleur et ventilateurs
récupérateurs d'énergie — Méthodes d'essai et de calcul des
facteurs de performances saisonnières —
Partie 2: Facteurs de performances saisonnières de la
récupération de froid sensible des ventilateurs récupérateurs de
chaleur (HRV)
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 2
5 Tests . 3
5.1 General requirements .3
5.2 Test conditions .3
5.3 Test methods .4
5.3.1 General .4
5.3.2 Energy saving stage limit temperature .4
5.3.3 Sensible cooling recovery performance test .4
5.3.4 The determination of bypass outdoor temperature .4
5.3.5 Measurement of power input of heat recovery ventilator with bypass ventilation
function.4
5.3.6 Measurement of power input of heat recovery ventilator with no bypass
ventilation function .5
6 Calculations . 5
6.1 Gross sensible cooling recovery effectiveness (ε ) .5
sc
6.2 Calculation of seasonal performance factor of sensible cooling recovery (F ) .5
sc
6.2.1 Reference outdoor air cooling load and sensible cooling recovery capacity .5
6.2.2 The characteristics of sensible cooling recovery capacity against outdoor
temperature .6
6.2.3 Power input characteristics of sensible cooling recovery against outdoor
temperature .7
6.2.4 Outdoor temperature bin distribution for cooling .7
6.2.5 Calculation of seasonal sensible cooling recovery capacity (E ) .7
sc
6.2.6 Calculation of seasonal sensible cooling recovery power input (P ) .8
in,E
6.2.7 Calculation of seasonal performance factor for sensible cooling recovery (F ) .8
sc
7 Test report . 8
Annex A (Informative) The schematic diagram of HRVs cooling (C) operation .10
Annex B (informative) The default outdoor temperature bin distribution for cooling.12
Annex C (informative) Calculating method for seasonal performance factor when setting a
specific application cooling load .13
Annex D (normative) The calculation of bypass outdoor temperature .15
Annex E (informative) Report template .16
Bibliography .18

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 86, Refrigeration and air-conditioning, SC 6,
Testing and rating of air-conditioners and heat pumps.
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iv
International Standard ISO 5222-2:2025(en)
Heat recovery ventilators and energy recovery ventilators —
Testing and calculating methods for seasonal performance
factor —
Part 2:
Sensible cooling recovery seasonal performance factors of
heat recovery ventilators (HRV)
1 Scope
This document specifies the testing and calculating methods for sensible cooling recovery seasonal
performance factor of heat recovery ventilators (HRV) covered by ISO 16494-1.
This document also specifies the test conditions and the corresponding test procedures for determining the
sensible cooling recovery seasonal performance factor of HRVs. The rating conditions are those specified in
Annex B and in ISO 16494-1. The procedures of this document can be used for other temperature conditions.
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.
ISO 16494-1:2022, Heat recovery ventilators and energy recovery ventilators — Method of test for performance
— Part 1: Development of metrics for evaluation of energy related performance
ISO 16494-1:2022/Amd 1:2023, Heat recovery ventilators and energy recovery ventilators — Method of test for
performance: Part1: Development of metrics for evaluation of energy related performance — Amendment 1
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16494-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
sensible cooling heat recovery
transfer of sensible energy from exhaust air to supply air in the HRVs while cooling
3.2
bypass ventilation function
function for reducing power input of the fans while the heat energy recovered is less than the additional
energy input due to overcoming the resistance of recovery heat exchanger during its operation time
Note 1 to entry: The bypass ventilation function makes the supply air and/or exhaust air go through the heat recovery
exchanger by bypass way with energy saving control.

3.3
sensible cooling gross effectiveness
ε
sc
measured effectiveness, not adjusted for leakage, motor heat gain, or heat transfer through the unit casing
Note 1 to entry: The sensible cooling gross effectiveness of an HRV, at equal airflow, is described in ISO 16494-1:2022 9.5.
3.4
net supply airflow
Q
m2, net
portion of the leaving supply airflow that originated as enter in supply airflow
Note 1 to entry: The net supply airflow is expressed in kg/s.
Note 2 to entry: The formulae for determining net supply air flow are given in ISO 16494-1:2022, 9.4.1 (ducted units)
and 9.4.2 (unducted units).
3.5
bypass outdoor temperature
T
b
outdoor temperature in cooling conditions, at which the electricity power reduction for the HRVs by
operating in bypass mode is equal to the saving of electricity power input to the cooling system due to the
heat recovered by the HRVs
3.6
seasonal performance factor of sensible cooling recovery
F
sc
ratio of seasonal amount of sensible cooling recovered together with power value of moving air to the whole
electricity input of HRVs, under the rating conditions and seasonal outdoor temperature bins selected from
this document
3.7
building cooling balance temperature
T
BCB
outdoor air temperature at which building heat gain equals to heat loss through the building envelope
4 Symbols and abbreviated terms
Symbol Description Unit
c Specific heat of leaving supply air (SA) kJ/(kg∙°C)
p
E Capacity of seasonal sensible cooling recovery Wh
sc
F Seasonal performance factor of sensible cooling recovery Wh/Wh
sc
L Reference outdoor air sensible cooling load at outdoor air bin tempera- W
sc,t,j
ture t
j
n Bin hours which the outdoor air bin temperature occurs h
j
n Number of temperature bins -
P Power input to ventilator at outdoor air bin temperature t W
in,t,j j
P Power input to the HRVs to operate the fans at outdoor ai
...