ISO/DIS 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

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 19467-2
ISO/TC 163/SC 1 Secretariat: DIN
Voting begins on: Voting terminates on:
2019-10-10 2020-01-02
Thermal Performance of windows and doors —
Determination of solar heat gain coefficient using solar
simulator —
Part 2:
Centre of glazing
ICS: 91.060.50; 91.120.10
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
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BEING ACCEPTABLE FOR INDUSTRIAL,
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ISO/DIS 19467-2:2019(E)
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2019
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ISO/DIS 19467-2:2019(E)
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ii © ISO 2019 – All rights reserved
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ISO/DIS 19467-2:2019(E)
Contents Page

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

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

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

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

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

4 Symbols and subscripts ................................................................................................................................................................................. 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 ...................................................................................................... 8

5.3.1 Hot box method ................................................................................................................................................................ 8

5.3.2 Cooled plate method ..................................................................................................................................................10

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 ........................................................................................................................16

6.2 Solar simulator .....................................................................................................................................................................................17

6.3 Climatic chamber ...............................................................................................................................................................................17

6.4 Metering box ..........................................................................................................................................................................................17

6.5 Surround panel ....................................................................................................................................................................................17

6.6 Calibration panels..............................................................................................................................................................................17

6.7 Metering location of temperatures .....................................................................................................................................17

6.8 Test specimens .....................................................................................................................................................................................17

6.9 Insulation of glazing edge ...........................................................................................................................................................17

7 Measurement procedure ...........................................................................................................................................................................18

7.1 Determination of surface coefficient of heat transfer ........................................................................................18

7.2 Measurement .........................................................................................................................................................................................18

8 Test report ................................................................................................................................................................................................................19

8.1 Report contents ...................................................................................................................................................................................19

8.2 Estimation of uncertainty ...........................................................................................................................................................20

Annex A (informative) Cooled plate method for SHGC measuring for the centre of glazing ...................21

Annex B (informative) Example of irradiation measurement ................................................................................................23

Annex C (informative) Determination of the irradiance-level for the cooled plate method

when divergence effects on the irradiance-level are not negligible ............................................................25

Annex D (informative) Specimen installation in surround panel .......................................................................................27

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

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ISO/DIS 19467-2:2019(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

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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).

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URL: 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, Working Group WG 17,

Solar heat gain coefficient of windows and doors.
A list of all parts in the ISO 19467 series can be found on the ISO website.
iv © ISO 2019 – All rights reserved
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ISO/DIS 19467-2:2019(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 may 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.

Solar heat gain coefficient values of the centre of glazing in fenestration systems with or without

shading devices shall be determined more precisely by means of combination between calculation and

measurement.

This part of ISO 19467 should be read together with ISO 19467:2017 Thermal performance of windows

and doors — Determination of solar heat gain coefficient using solar simulator.
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DRAFT INTERNATIONAL STANDARD ISO/DIS 19467-2:2019(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 9050, Glass in building — Determination of light transmittance, solar direct transmittance, total solar

energy transmittance, ultraviolet transmittance and related glazing factors

ISO 9845-1, Solar energy — Reference solar spectral irradiance at the ground at different receiving

conditions — Part 1: Direct normal and hemispherical solar irradiance for air mass 1,5

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

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ISO/DIS 19467-2:2019(E)

ISO 19467, 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

ISO 52022-3, Energy performance of buildings — Thermal, solar and daylight properties of building

components and elements — Part 3: Detailed calculation method of the solar and daylight characteristics

for solar protection devices combined with glazing

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 apply. In addition to the typical terms

and definitions above, specified terms and definitions for this document are followed.

3.1
centre of glazing
centre of glazing is the area undisturbed by edge and frame effect.
3.2
off-normal irradiance

off-normal irradiance is the condition where the altitude angle and/or azimuth angle of incident

radiation is not equal to 0°. For off-normal irradiance, altitude angle and azimuth angle shall be

specified.
3.3
projected area

the 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 Annex D.
3.4
simple fenestration system

optically and thermally simple fenestration systems are fenestration products having homogeneous

specular and transparent properties with non-ventilated cavities, e.g., glazing units made from glass

and/or polymers, with or without coating.
3.5
complex fenestration system

optically and/or thermally complex fenestration systems (CFS) are fenestration products that are not

described as simple fenestration systems, e.g., optically scattering glazing and/or shading devices and/

or ventilated cavities and/or PV cells and/or solar collectors.
3.6
solar wavelength range

solar wavelength range is the range defined in ISO 9050 used for solar properties.

4 Symbols and subscripts
Table 1 — Symbols and units
Symbol Quantity Unit
A Area m
f Ratio of irradiation difference to distance difference -
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ISO/DIS 19467-2:2019(E)
Table 1 (continued)
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)
Table 2 — Subscriptions and abbreviations
Subscripts Significance
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/DIS 19467-2:2019(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

in net
due 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 standard 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
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ISO/DIS 19467-2:2019(E)

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

surface of the test specimen.
IA⋅
∑ netc,,iiog
i=1
I = (2)
net
cog
where

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

net,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 along a

cog,i
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
NOTE Equal distribution of the sensing positions should be used.

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
1 solar simulator (normal and off-normal) 4 test specimen
2 x-axis 5 cooling device or absorber
3 metering box or insulation box 6 lighting generated by solar simulator
Figure 1 — Influence of beam divergence of the incident irradiation

As already stated, 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.
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ISO/DIS 19467-2:2019(E)

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).
net,i
II=+1 fx −x (4)
()()
net,iiscan,scanref
where

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

scan,i
point, 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 the external surface of the test specimen

ref
(reference plane for the irradiance measurement), in m.
NOTE Direction of x and x should be normal to the test specimen.
scan ref
Key
1 solar simulator (normal and off-normal) 5 cooling device or absorber
2 x-axis 6 lighting projected by solar simulator
3 metering box or insulation box 7 measuring plane of irradiance scan (x )
scan
4 test specimen 8 measuring 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
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ISO/DIS 19467-2:2019(E)
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

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 irradiance as described in Annex C.

This additional systematic (non-statistical) error should be taken into account in the determination of

the uncertainty of the g-value measurement. For the cooled plate method, the procedure in Annex C

might be used to determine the irradiance level which is relevant for the evaluation of the calorimetric

measurement.
Key
1 solar simulator (normal and off-normal) 5 cooling device or absorber
2 x-axis 6 lighting generated by solar simulator
3 metering box or insulation box 7 measuring plane 1 of irradiance scan (x )
scan,1
4 test specimen 8 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 .
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ISO/DIS 19467-2:2019(E)

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/DIS 19467-2:2019(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 thermal

in net
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 edge with
INS
irradiance

NOTE 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

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).
ΦΦ−−ΦΦ−−ΦΦ
...