Smart Buildings
and the future of Middle East
Energy Efficiency in Buildings
- Coatings on Architectural Glass
Micha Pawelka
Interpane Glass Germany – Office Middle East
Content
 Introduction
 Thin film coatings on glass
 Color
 Summary
Introduction
Introduction
It is a minor object
- the window glass what I mean –
but if it fails, it is very important.
Mark Twain
Primary benefits
(amongothers)

Supply with natural daylight

Protection against rain, wind,
heat & cold

Transparency or translucency

Means of communication

Supply with fresh air
Secondary benefits
(among others)

Thermal insulation

Acoustic insulation

Solar control

Sustainability

Object and personal security

Fire protection

Utilization of solar energy

Comfort

Means of design

Structural Element
Demands on glass in architecture
 Aesthetics
 Creative Liberties / Geometries/ Shapes
 Colouring
 Reflectance
 Energy Efficency– climatical adjusted to regional needs
Minimum cooling in summer  large glass facades
Reducing the loss of heat in winter - however transmit light and energy
 Comfort
 Indoor Climate
 „Flexible“ Product
 Production/ Logistics
Thin film coatings on flat glass
Glass follows function…
Different Groups of coatings
 optical properties (influencing the transmission, reflection &
absorption)
 electrical properties (e.g. emissivity)
 mechanical properties (e. g. changing the dirt and waterrepelling potential)
 chemical properties (e. g. protective layers against chemical
attacks)
 decorative properties (changing the appearance of a glazing)
Difference of thin film & thick film coatings
thin film coating
thickness ≤ 1µm
e.g. materials deposited from the vapour phase in a vacuum or
from vapour, liquid or solid phase under atmospheric conditions
thick film coating
e. g. lacquer, resin or foil coatings
thickness > 1µm
Thin film coatings on flat glass
 Thermal insulation
 Solar control - selective & non selective
 Design applications
 „Self cleaning glass“
 Shielding glass for electromagnetic radiation
 Radar signal attenuation
 Anti-reflective glass
 Conductive coatings e.g. für electrochromic or heatable
glass
 Coatings for solar applications – photovoltaics, solar heat
 Mirrors
Complex
system of
electric
conductivity &
interference
intermediate layer
intermediate layer
Solar control
Principle Structure of a coating on glass
Low E
Classification of coated glass EN 1096
Category
A
B
C
D
S
Description
The coating can be used
room sided and weather
sided
Can be used for single
glazings, coating only to the
room side
Coating only to the cavity of
insulating glass
Application
Example
Standard
Monolithic,
Titanium-Oxide coating, EN 1096-2
Insulating glass self-cleaning coatings
Monolithic,
oxide based solar
EN 1096-2
Insulating glass control coating
(ipasol „bright“)
Insulating glass Solar control and
EN 1096-3
thermal insulating glass
on silver basis
Insulating glass Gold sputtering coatingsEN 1096-3
Like category C, must be
processed to insulating
glass directly after production
Coating to room side or
Monolithic,
Antireflection-coatings, EN 1096-2
outside of the building, such Insulating glass low-reflecting surfaces
as shop fronts
Solar Spectrum
intensity of radiation/W/m²µm
Energy Contributions:
100% = 4% UV + 55% VIS + 41% NIR
Visible
1200
Solar Radiation
1000
800
short wave thermal radiation
600
400 4%
55%
41%
200
0
500
UV VIS
1000
1500
NIR
Wave length [nm]
2000
2500
Basically
Absorption
Transmission
+ Absorption
+ Reflection
Σ 100% Solar Radiation
Reflection
Reflection
Transmission
Solar Radiation
Radiation in detail
Thermal Insulation & Solar Control
Principal Types
I. Thermal Insulation Glazing
• High solar factor (g value)
• High visible light transmission TV
II. Solar control Glazing
• On cooling load adjusted solar factor (g value)
• Maximized light transmission- depending on the solar factor
Basically:
• Good thermal insulation = low Ug-Value
Additional Requirements:
III. Optimized Triple Glazing („passive house“)
• Reduced Ug-Wert 0,5 bis 0,7 W/(m²K) at a
maximized solar factor & light transmission
Thermal Insulation & Solar Control
RTA Diagramm for a Low E coating
UV
VIS
NIR
RTA Diagramm for ipasol neutral 70/39
UV
VIS
NIR
RTA Diagramm for ipasol platin 25/15
UV
VIS
NIR
Light Transmission τL
Selectivity Ration S
Solar Control Glass
Thermal Insulation
SHGC or g-value
Dr. Gunter Pültz, Müller BBM,
Poster Glasmuster
Coating Types
Different solar high performance coatings offers a wide range of
possibilites for design and the compliance with the requirements of
building physics values

Solar factor range from 42% down to 15%
Influencing the solar factor
 Increasing the energy absorption due to tinted glass or coatings
 High reflective coatings
 Combination of absorbing glass with selective coatings
 Size of the IGU Cavity
 Kind of gas filling (Air, Argon, Krypton)
 Type of glass (e. g. low iron glass) & glass thickness
 Additional features e. g. IGU with blinds in the cavity
 Electrochromic switchable glass e. g. E-Control
 Printed, coated or colored interlayer for laminated glass
 Position of the coating
 Surface treatment e.g. printings (coverage!)
Coating Positions
total energy transmission
70/39 Pos. 3
solar factor 49%
4/16Ar/:6
35.7
70/39 Pos. 2
solar factor 39%
6:/16Ar/4
35.7
internal secondary heat gain
14.6
2.8
radiation
total energy transmission
reflection
absorption
external secondary heat gain
solar factor
internal secondary heat gain
Impact of the solar factor
Printing on glass- Hamilton House
ipasol neutral 70/39 + white ceramic frit on pos. #2
6: - 16 Argon - 4
100
T(L)
Data
80
60
R(Le)
direct +
diffuse
40
20
solar factor
0
0
20
40
60
80
100
Coverage
Sample: 50% coverage
Light transmission:
40 [%]
Solar factor:
24 [%]
performance data acc. EN 410 +/- 5% absolutely
ipasol neutral 70/39 + black ceramic frit on pos. #2 \
6: - 16 Argon - 4
100
T(L)
Data
80
60
R(Le)
direct +
diffuse
40
20
solar factor
0
0
20
40
60
80
100
Coverage
Sample: 50% coverage
Light transmission:
35 [%]
Solar factor:
22 [%]
performance data acc. EN 410 +/- 5% absolutely
Non Selective Coatings
RTA Diagramm for
ipasol bright neutral 6mm
UV
VIS
NIR
RTA Diagramm for
ipasol bright grey 6mm
UV
VIS
NIR
Non-Selective Coatings
Design Coatings
Design Coatings
Design by Foreign Office Architects
Design Coatings
Design by Foreign Office Architects
Technical performances in insulating
glass:
6 mm ipachrome design on face 2,
over coated with ipasol neutral 70/39
16 mm argon
6 mm float
* 25% covered with ipachrome design
TL: 53% RLe: 23% g: 30% Ug: 1.1 W/m²K
* 50% covered with ipachrome design
TL: 37% RLe: 33% g: 22% Ug: 1.1 W/m²K
The calculated data are based on spectral measurements in accordance with EN 410
Tolerances with respect to the photometric properties: +/- 3
The determination of the characteristics
is within the responsibility of planning
 Thermal Transmittance coefficient Ug in W/(m²K)
 Solar Factor (SF or g value) in %
 Light transmission TL in %
 Light reflectance outside RL,a in %
 General colour rendering index Ra,D (dimensionless)
 Selectivity S (quotient of TL and g value, dimensionless)
with influence on the glass thickness and the glass
build up
 Sound insulation index Rw in dB
 Necessary minimum glass thickness due to structural,
safety and climate load requirements
High Performance Coatings against performance data
Light Transmission (L)
Selectivity
S = L / SC
Colour Absorption,
Reflexion
Ug
Solar Factor SC
Impression
Energy Absorption,
Reflexion
Colour
Color Rendering Index
External appearance: Ra,R
Color index via reflectance
Interpretation of the colors of
the external facade (Ra).
The glass reflects the light.
The color index via reflectance
is Ra,R
Internal appearance: Ra,D
Color index via transmittance
Interpretation of colors in the
interior (Ra). The light passes
through the glass.
The color index via transmittance
is Ra,D
The CIELAB colour coordinate system
(CIE 1976)
E* 
a *  b *
2
2
 L *
2
Summary
Coatings should be…
Future !?- No realistic!
Future !?- No realistic!
#1
#2
#3
#4a
#4b
#5
#6
#7
#8
Heat strengthened glass 8 mm
Design: Textured ‚Metal‘ Coating
PVB-Interlayer
Heat strengthened glass 8 mm
High performace coating
Design: grey screen printing
Cavity 16 mm Argon
Low E coating
Clear float 6 mm
PVB-Interlayer
Clear float 6 mm
Summary
 The physical limits will be tested
 Double and triple layer insulating glass is the
future
 Different requirements can be met with the
material glass and particularly with thin film
coatings
 In future nearly every surface of an IGU will have
an coating
 It is important for architects, planners, clients
and glass consultants to work together from an
early stage to reach a solution that meets all the
requirements
Thank you very much for your attention!
www.interpane.com
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