ISO/FDIS 19467-2

Thermal Performance of windows and doors -- Determination of solar heat gain coefficient using solar simulator

Performance thermique des fenêtres et portes -- Détermination du coefficient de gain thermique solaire au moyen d'un simulateur solaire

General Information

• Status: Published
• ICS: 91.060.50 - Doors and windows
• ICS: 91.120.10 - Thermal insulation of buildings
• Technical Committee: ISO/TC 163/SC 1 - Test and measurement methods
• Drafting Committee: ISO/TC 163/SC 1/WG 17 - Solar heat gain coefficient of windows and doors
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 12-May-2021
• Completion Date: 12-May-2021

Standards Content (sample)

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 19467-2
ISO/TC 163/SC 1
Thermal Performance of windows
Secretariat: DIN
and doors — Determination of solar
Voting begins on:
2021-05-12 heat gain coefficient using solar
simulator —
Voting terminates on:
2021-07-07
Part 2:
Centre of glazing
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 19467-2:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
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ISO/FDIS 19467-2:2021(E)
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ii © ISO 2021 – All rights reserved
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ISO/FDIS 19467-2:2021(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols .......................................................................................................................................................................................................................... 2

5 Principle ........................................................................................................................................................................................................................ 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Measurement of the irradiance ................................................................................................................................................ 4

5.2.1 General...................................................................................................................................................................................... 4

5.2.2 Determination of the net radiant flux (power) of incident radiation ................................. 4

5.2.3 Calculation of I with correction of reflected by the absorber ............................................. 7

net

5.3 Measurement of heat flow rates with irradiance ...................................................................................................... 7

5.3.1 Hot box method ................................................................................................................................................................ 7

5.3.2 Cooled plate method ..................................................................................................................................................... 9

5.4 Determination of the net density of heat flow rate due to thermal transmission .....................11

5.5 Measurement of heat flow rates without irradiance ...........................................................................................11

5.5.1 Thermal transmittance ........................................................................................................................................... .11

5.5.2 Hot box method .............................................................................................................................................................11

5.5.3 Cooled plate method ..................................................................................................................................................13

6 Test apparatus and specimens ............................................................................................................................................................14

6.1 Construction and summary of the test apparatus .................................................................................................14

6.1.1 Construction of the test apparatus ................................................................................................................14

6.1.2 Summary of the test apparatus ........................................................................................................................15

6.2 Solar simulator .....................................................................................................................................................................................15

6.3 Climatic chamber ...............................................................................................................................................................................16

6.4 Metering box ..........................................................................................................................................................................................16

6.5 Surround panel ....................................................................................................................................................................................16

6.6 Calibration panels..............................................................................................................................................................................16

6.7 Metering location of temperatures .....................................................................................................................................16

6.8 Test specimens .....................................................................................................................................................................................16

6.9 Insulation of glazing edge ...........................................................................................................................................................16

7 Measurement procedure ...........................................................................................................................................................................17

7.1 Determination of surface coefficient of heat transfer ........................................................................................17

7.2 Measurement .........................................................................................................................................................................................17

8 Test report ................................................................................................................................................................................................................18

8.1 Report contents ...................................................................................................................................................................................18

8.2 Estimation of uncertainty ...........................................................................................................................................................19

Annex A (informative) Cooled plate method for SHGC measuring for the centre of glazing ...................20

Annex B (informative) Example of irradiation measurement ................................................................................................22

Annex C (informative) Consideration of effects caused by the divergence of the incident light .........24

Annex D (informative) Specimen installation in surround panel .......................................................................................29

Bibliography .............................................................................................................................................................................................................................32

© ISO 2021 – All rights reserved iii
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ISO/FDIS 19467-2:2021(E)
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 be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use

in the built environment, Subcommittee SC 1, Test and measurement methods.
A list of all parts in the ISO 19467 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved
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ISO/FDIS 19467-2:2021(E)
Introduction

This document is designed to provide solar heat gain coefficient values of the centre of glazing in

fenestration systems by standardized measurement method. The terms solar heat gain coefficient

(SHGC), total solar energy transmittance (TSET), solar factor and g-value are all used to describe the

same quantity. Small differences might be caused by different reference conditions (e.g. differences in

the reference solar spectrum). In this document, solar heat gain coefficient is used.

The solar heat gain coefficient of a complex fenestration system can depend on the direction of the

incident radiation. It also might be influenced by other factors, e.g. window frame. In order to avoid

the complexity and to enable the measurement of off-normal irradiation, this document focuses on the

centre of glazing in fenestration systems.

This document specifies standardized apparatus and criteria. The solar heat gain coefficient measuring

apparatus applied in this document includes solar simulator, climatic chamber, and metering box. In

some cases, solar heat gain coefficient of the centre of glazing can be determined most accurately by a

combination of calculations and measurements.
© ISO 2021 – All rights reserved v
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 19467-2:2021(E)
Thermal Performance of windows and doors —
Determination of solar heat gain coefficient using solar
simulator —
Part 2:
Centre of glazing
1 Scope

This document specifies a method to measure the solar heat gain coefficient for the centre of glazing in

fenestration systems (e.g. complete windows, doors or curtain walls with or without shading devices)

for normal and off-normal irradiation on the surface.

This document applies to the centre of glazing in fenestration systems which might consist of:

a) various types of glazing (e.g. glass or plastic; single or multiple glazing; with or without low

emissivity coatings, and with spaces filled with air or other gases; opaque or transparent glazing);

b) various types of shading devices (e.g. blind, screen, film or any attachment with shading effects);

c) various types of active solar fenestration systems [e.g. building-integrated PV systems (BIPV) or

building-integrated solar thermal collectors (BIST)].
This document does not include:
a) shading effects of building elements (e.g. eaves, sleeve wall, etc.);

b) shading effects of fenestration attachments with overhang structures (e.g., awning, etc.) or similar;

c) shading effects of non-glazing elements in fenestration systems (e.g. window frame, etc.);

d) heat transfer caused by air leakage between indoors and outdoors;
e) ventilation of air spaces in double and coupled windows;

f) thermal bridge effects at the joint between the glazing and the rest of the fenestration parts (e.g.

window frame, etc.).
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 7345, Thermal performance of buildings and building components — Physical quantities and definitions

ISO 9050, Glass in building — Determination of light transmittance, solar direct transmittance, total solar

energy transmittance, ultraviolet transmittance and related glazing factors

ISO 12567-1, Thermal performance of windows and doors — Determination of thermal transmittance by

the hot-box method — Part 1: Complete windows and doors

ISO 15099, Thermal performance of windows, doors and shading devices — Detailed calculations

© ISO 2021 – All rights reserved 1
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ISO/FDIS 19467-2:2021(E)

ISO 19467:2017, Thermal performance of windows and doors — Determination of solar heat gain coefficient

using solar simulator

ISO 52016-1, Energy performance of buildings — Energy needs for heating and cooling, internal

temperatures and sensible and latent heat loads — Part 1: Calculation procedures

IEC 60904-9, Photovoltaic devices — Part 9: Solar simulator performance requirements

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 7345, ISO 9050, ISO 9288,

ISO 12567-1, ISO 15099, ISO 19467, ISO 52016-1 and IEC 60904-9 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
centre of glazing
central area of the glazing, undisturbed by edge and frame effects
3.2
off-normal irradiance
irradiation with altitude and/or azimuth angle not equal to 0°
3.3
projected area

area of the projection of the surface of the element on to a plane parallel to the transparent or translucent

part of the element
Note 1 to entry: In the case of non-parallel condition, refer to Annex D.
3.4
simple fenestration system

fenestration products having non-ventilated glazing units made from glass and/or polymers and

homogeneous specular and transparent properties in optical and thermal.
Note 1 to entry: In the case of non-parallel condition, refer to Annex D.
3.5
complex fenestration system

optically and/or thermally complex fenestration products that are not described as simple fenestration

systems (3.4)

EXAMPLE optically scattering glazing and/or shading devices and/or ventilated cavities and/or PV cells

and/or solar collectors.
3.6
solar wavelength range
range of wavelengths for the incident radiation used for solar properties

Note 1 to entry: The range of wavelengths for the incident shall be as specified in ISO 9050.

4 Symbols
Symbol Quantity Unit
A Area m
f Ratio of irradiation difference to distance difference -
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ISO/FDIS 19467-2:2021(E)
Symbol Quantity Unit
Solar heat gain coefficient (also known as total solar energy trans-
g —
mittance, solar factor or g-value)
h Surface coefficient of heat transfer W/(m ·K)
H Height m
Density of heat flow rate (energy per unit area per unit time resulting
q W/m
from radiative and/or convective and/or conductive heat transfer)
Irradiance, radiant flux (power) of incident radiation (energy per
I W/m
unit area per unit time resulting from incident radiation)
U Thermal transmittance W/(m ·K)
W Width m
x Distance or position m
θ Celsius temperature °C
Heat flow rate (energy per unit time resulting from radiative and/
Φ W
or convective and/or conductive heat transfer)
τ Transmittance -
Subscripts Meaning
B Planes of peripheral wall of the metering box
C Cooling device
cog Centre of glazing
ex External
F Internal fan
H Heating device
i Number (Index)
in Internal
INS Insulation
N Without irradiance
net Net (Resulting quantity)
ne Environmental external
ni Environmental internal
P Surround panel
r Reflection
ref Reference
scan Scan
si Internal surface
se External surface
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ISO/FDIS 19467-2:2021(E)
5 Principle
5.1 General

The solar heat gain coefficient for the centre of glazing in fenestration systems, g , can be determined

cog

according to the same principle described in ISO 19467. Therefore, it shall be calculated using

Formula (1) with or without shading devices.
qq− I =0
in in net
g = (1)
cog
net
where
I is the net radiant flux (power) of incident radiation, in W/m2;
net

q is the net density of heat flow rate through the test specimen in the centre of glazing

with irradiance, in W/m ;

q (I = 0) is the net density of heat flow rate through the test specimen in the centre of glazing due

in net

to thermal transmission without irradiance when the temperature difference between

internal side and external side is (θ – θ ), in W/m .
ne ni
Main differences between ISO 19467 and this document are as follows:

— this measurement deals with not the complete fenestration systems but the centre of glazing in

fenestration systems;
— irradiance can be emitted also from off-normal incidence (see 5.2);

— not only “hot-box method” but also “cooled plate method” are adopted (see 5.3, 5.4, and 5.5).

5.2 Measurement of the irradiance
5.2.1 General

The determination of the net radiant flux (power) of incident radiation of the centre of glazing in

fenestration systems involves three stages. The first stage is to scan the irradiation. The second stage is

to take the irradiation divergence by distance between test specimen and lamp into account. The third

stage is to calculate the net radiant flux (power) of the incident radiation in the solar wavelength range.

5.2.2 Determination of the net radiant flux (power) of incident radiation

Since the solar simulator cannot provide ideally parallel incident radiation to the test specimen, the

irradiance depends on the distance between the solar simulator and each part of the test specimen and

is not ideally homogeneous on the surface of the test specimen as shown in Figure 1. In order to take

into account the inhomogeneity of the irradiance, net radiant flux (power) of incident radiation, I ,

net

shall be calculated using Formula (2), which is the area-weighted average irradiance at the external

surface of the test specimen on which sensing position should be equally distributed.

IA⋅
netc,,iiog
i=1
I = (2)
net
cog
where
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ISO/FDIS 19467-2:2021(E)

I is the corresponding net radiation flux (power) of incident radiation for each measurement

net,i
point, i, along a vertical line in the plane of the test specimen, in W/m ;

A is the corresponding projected area for each measurement point, i, in the centre of glazing

cog,i
along a vertical line in the plane of the test specimen, in m ;
A is the projected area of the centre of glazing in the test specimen, in m .
cog

The projected area of the centre of glazing in the test specimen, A , shall be identical to the sum of the

cog
projected area for each measurement point, A , as shown in Formula (3).
cog,i
AA= (3)
cogcog,i
i=1

Sensors shall be in the centre of each divided area. More information is given in Annex B. The projected

area of the centre of glazing in the test specimen, A , for both the cooled plate method and the hot box

cog
method can be determined according to Annex A and Annex D, respectively.
Key
X x-axis 3 test specimen
1 solar simulator (normal and off-normal) 4 cooling device or absorber
2 metering box or insulation box 5 lighting generated by solar simulator
Figure 1 — Influence of beam divergence of the incident irradiation

Solar simulators do not provide ideally parallel radiation, therefore the irradiance depends on the

distance from the solar simulator. The individual layers of the test specimen and the absorber in the

case of cooled plate method are thus irradiated with slightly different irradiance values as shown in

Figure 2.

The irradiance may also be determined in a different plane in front of the test specimen. In this case,

I shall be calculated using Formula (4). The influence of divergent irradiation on the position of X

net,i ref
should be taken into account according to Annex C for the cooled plate method.
II=+1 fx −x (4)
()()
net,iiscan,scanref
where
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ISO/FDIS 19467-2:2021(E)

I is the corresponding net radiant flux (power) of incident radiation for each measurement point,

scan,i
i, at the position x , in W/m ;
scan
f is the variation ratio of the irradiance, in m ;

x is the distance between the solar simulator and the scanning radiometer, in m;

scan

x is the distance between the solar simulator and reference plane for the irradiance measure-

ref
ment, in m.
NOTE Directions of x and x are normal to the test specimen.
scan ref
Key
X x-axis 4 cooling device or absorber

1 solar simulator (normal and off-normal) 5 lighting projected by solar simulator

2 metering box or insulation box 6 measuring plane of irradiance scan (x )
scan
3 test specimen 7 plane of reference irradiance (x )
ref

Figure 2 — Determination of reference irradiance when the sensor cannot be put in the plane of

reference irradiance

In order to take into evaluate the variation of the irradiance level from the distance of the absorber, the

criterion f might be used according to Formula (5).
scan,1
scan,2
f = (5)
xx−
scan,2 scan,1
where
x is the measuring plane1 of irradiance scan in m (key 7 in Figure 3);
scan,1
x is the measuring plane 2 of irradiance scan in m (key 8 in Figure 3);
scan,2
I is the irradiance on the measuring plane 1, in W/m (key 7 in Figure 3);
scan,1
I is the irradiance on the measuring plane2, in W/m (key 8 in Figure 3).
scan,2
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ISO/FDIS 19467-2:2021(E)

If the irradiance sensor cannot be put in the reference plane and f is greater than 0,07 %/mm, f should

be taken into account to analyse the additional uncertainty of the irradiance level due to divergence

effects as shown in Figure 3 and the correction of the reference plane as described in Annex C as already

mentioned before Formula (4). This additional systematic (non-statistical) error should be taken into

account in the determination of the uncertainty of the g-value measurement.
Key
X x-axis 4 cooling device or absorber

1 solar simulator (normal and off-normal) 5 lighting generated by solar simulator

2 metering box or insulation box 6 measuring plane 1 of irradiance scan (x )
scan,1
3 test specimen 7 measuring plane 2 of irradiance scan (x )
scan,2

Figure 3 — Determination of irradiance in different planes in front of the test specimen

5.2.3 Calculation of I with correction of reflected by the absorber
net

The net density of the heat flow rate of the incident radiation, I , shall be calculated using Formula (6).

net,i
II=−I (6)
net,iiscan, r

where I is the density of heat flow rate of the incident radiation that is transmitted to the external side

of the metering box/plate after being reflected the internal side of the metering box/plate, in W/m .

If I is proved to be negligible (I approximately 0), the net radiant flux (power) of incident radiation, I ,

r r net

shall be calculated using Formula (7), which results in the second term on the right side of Formula (6)

to become 0.
II= (7)
net,iiscan,

Whether I is negligible or not shall be evaluated based on the criteria stated in ISO 19467.

5.3 Measurement of heat flow rates with irradiance
5.3.1 Hot box method

The heat flow rates with irradiance for the hot box method are shown in Figure 4.

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ISO/FDIS 19467-2:2021(E)
Key

1 external side baffle(optional) Φ heat flow rate through the planes of peripheral wall

of the metering box with irradiance

2 internal side baffle (optional) Φ heat flow rate removed by the cooling device with

irradiance
3 cooling device Φ heat flow rate supplied by the one or more internal
fans with irradiance (optional)

4 heat flow measuring device Φ heat flow rate supplied by the heating device with

irradiance (optional)
5 internal fan(optional) Φ net heat flow rate through the test specimen with
irradiance

6 heating device(optional) Φ (I = 0) net heat flow rate through the test specimen due to

in net
thermal transmission without irradiance when the
temperature difference between internal side and
external side is (θ – θ )
ne ni
7 test specimen Φ heat flow rate through the surround panel with
irradiance
8 insulation of glazing edge Φ net radiant flux (power) of incident radiation
net
Φ heat flow rate through the insulation of the glazing
INS
edge with irradiance

This figure shows the case of a condition when the environmental external temperature is higher than the

environmental internal temperature. In the case of a reverse condition, the directions of the heat flow through the

test specimen and the surround panel due to thermal transmission will be reversed. If the internal baffle is not

present, the difference between air temperature and radiative temperature should be minimized.

Figure 4 — Heat flow rates with irradiance for the hot box method
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ISO/FDIS 19467-2:2021(E)

The net density of heat flow rate through the test specimen with irradiance, q , for the hot box method

shall be calculated using Formula (8). In the formula, Φ should be estimated by the two-dimensional

INS
calculation.
ΦΦ−−ΦΦ−−ΦΦ−
CB FH PINS
q = (8)
cog
where

Φ is the heat flow rate removed by the cooling device with irradiance, in watts;

Φ is the heat flow rate through the planes of peripheral wall of the metering box with irradi-

ance, in watts;

Φ is the heat flow rate supplied by the one or more internal fans with irradiance (optional), in

watts;

Φ is the heat flow rate supplied by the heating device with irradiance (optional), in watts;

Φ is the heat flow rate through the surround panel with irradiance, in watts;

Φ is the heat flow rate through the insulation of the glazing edge with irradiance, in watts.

INS
A is the projected area of the centre of glazing in the test specimen, in m .
cog
5.3.2 Cooled plate method

The heat flow rates with irradiance for the cooled plate method are shown in Figure 5.

© ISO 2021 – All rights reserved 9
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