Glass and thermal insulation

2008 Technical Advisory Service

Thermal Insulation Solar Control Aesthetic and decoration Acoustic Insulation Safety

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC Flat Glass Europe range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Introduction low t° high t°

Introduction 0°C 20°C

Necessary power ?

P = S (m²) x

D

T (°C) x Ug (W/m² °C)

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Conduction, convection and radiancy Conduction Convection Radiancy

Conduction, convection and radiancy

Outdoor temperature :

T out

Indoor temperature :

T in

Radiation Radiation Conduction Convection (and conduction) Convection (and conduction)

Ug-value = Heat loss Temperature difference

(W/m².K)

Conduction, convection and radiancy Intensity (W/m²) 1.5

Energy UV Light Short infra red 1.0

0.5

0 0 280 380 780 2500 Wavelength (nm)

Conduction, convection and radiancy Solar spectrum : UV : 280 tot 380 nm  5% energy Light : 380 tot 780 nm  50% energy Short I.R. : 780 tot 2500 nm  45% energy

Conduction, convection and radiancy

Solar radiancy Radiators V is ib le Close IR Long IR Radio waves

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window Regulation

Single glazing 4  glass = 1 W/(m K)  alu = 160 W/(m K)  insulating material  0,065 W/(m K)  : thermal conductivity

Single glazing 4 19 mm  glass = 1 W/(m² K)  insulator < 0,065 W/(m² K) Ug = 5,8 W/(m² K) Ug = 5,4 W/(m² K)

Single glazing 6.00

5,8 5.50

5.00

4.50

4 5 6 8 10

Glass thickness (mm)

12 15 19 5,4

Single glazing 700 mm Ug = 1.1 W/(m² K)

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  High output double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Double glazing Ug = 5,8 W/(m² K) Ug = 2,9 W/(m² K)  glass = 1 W/(m² K)  air = 0,025 W/(m² K)

Double glazing 4,00 3,00 2,9 2,00 1,00 4 6 8 10 12 14 16 18

Width of the spacer (mm)

20 22 24

Double glazing - composition Thermobel Air Float Float Butyl Spacer Dryer Sealing

Double glazing - composition  2 glazings  Spacer  Gas  Dryer for absorbing humidity  Primary barrier of sealing (humidity) : – Butyl  Secondary barrier of sealing (sealing) : – Polyurethane – Silicone

Double glazing Ug = 2,9 W/(m² K) Ar Kr Ug  2,6 W/(m² K)

Double glazing 3,50 3,00 4-x-4 air 4-x-4 argon 4-x-4 krypton 2,50 2,00 4 6 8 10 12 14 16

Width of spacer (mm)

18 20 22 24

Double glazing Ug = 2,9 W/(m² K) Ug  2,0 W/(m² K)

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Double glazing

Outside UV, visible, short IR Inside

Long IR > 2500 nm

Double glazing e n =0.89

e n =0.89

Long IR > 2500 nm

Double glazing  Glass is not transparent to long IR  Glass then absorbs the heat which tries to leave the building  In winter, when it is colder outside than inside, the major part of this absorptive energy is re-emitted towards outside

Low e double glazing Heat Ug = 2,9 W/(m² K) Ug = 1,4 to 2,0 W/(m² K) LowE coating

Low e double glazing Low emissivity coating :  n=0.15 to 0.02

Long IR > 2500 nm e n =0.89

Low e double glazing

UV, visible, short IR

Long IR > 2500 nm e n =0.89

Low e double glazing  The low-e coating forces the reemission of the absorbed heat by glass towards the interior  I.e. that it behaves as a mirror which reflects the heat which tries to leave the building  On the other hand, it does not prevent the solar radiation from penetrating in the building

Low e double glazing  Physically : – Glass is opaque to long IR (ET = 0) – From where the result of a heating of glass and reemission – The low-e coating forces the reeimisson towards outside e = AE = 1 – TR – RE = 1 – RE  The lower is emissivity, the higher is the energy reemission towards the interior

Low e double glazing Clear glazing : emissivity e = 0,89 Coatings :  pyrolithic low-e: e about 0,15 to 0,30  Vacuum (magnetron): e about 0,02 à 0,1

Low e double glazing 3,50 3,00 2,50 2,00 1,50 4-x-4 air e = 0,89 1,00 4 6 8 10 12 14 16

Width of spacer (mm)

18 20 22 24

Double glazing with Warm Edge spacer The metallic spacer (alu, steel, …) is replaced by a plastic spacer (eventually reinforced).

Double glazing with Warm Edge spacer Advantages:  Improvement of the U-value of the frame ( not  the glazing )  economy of energy The surface temperature is more uniform  better comfort Without Warm Egde With Warm Edge

Low e double glazing In short : – Thickness of glass : insignificant – Gas (argon): small improvement – Low emissivity coatings   Big improvement Low e double glazing – Warm-Edge spacer  Improvement of the insulation of the frame

Double glazing In short : Ar Ug = 5,8 W/(m² K) Ug = 2,9 W/(m² K) Ug from 1,4 to 2,0 W/(m² K) Ug = 1,1 W/(m² K)

Triple glazing Ar Kr Ar Kr Ug from 0,5 to 0,9 W/(m² K)

Thermal losses of a dwelling...

Roof : 20% Walls : 25% Ground : 20% Windows account for about 35% !

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Temperature of surface and comfort 17,3° 18,5 ° 20° 12,8° 5,6° 0° Planibel 4 mm Outside

Ug =5,8

Thermobel 4-12-4 mm Thermobel Top N+ 4-15 ar-4 mm

Ug = 2,9 Ug = 1,1

Thermobel Triple 4-15 ar-4 -15 ar-4

Ug = 0,6

Inside

Glass and thermal insulation   Introduction Convection, conduction and radiancy       Single glazing Double glazing Low e double glazing Temperature of surface and comfort AGC range Condensation    Calculation of the Ug-value of a glazing Calculation of the Uw-value of a window Regulation

1970 1980 1990 2000

Technology

Dial Sputtering

Lodelinsart

Magnetron sputtering

Lodelinsart / Tiel / Teplice

Pyrolytic (Spray)

Moustier

Pyrolytic (CVD)

Moustier

Gold Thermoplus Single silver Thermobel (Plus, Top, Top N, Energy) Top N+, Top NT, Energy N Thermoplus Comfort K Glass Planibel G

1970 1980 1990 2000

AGC range – low-e coatings

Magnetron Pyrolytic Neutral low-e glas

(Planibel Top) (Planibel Plus) Planibel Top N+ Planibel Top NT

Neutral low-e and solar control glass

Planibel Energy N Planibel Energy NT Planibel (K glass) Planibel G

Solar control glass

Stopray Sunergy

AGC range – Thermobel  Ug = 2,8 W/m²K  LT = 81 % - SF = 77 %  Dimensions max : 3210 mm x 6000 mm  Thicknesses : 4 to 19 mm  Processings : tempering, laminating, silk screening, bending

AGC range – Thermobel Alternatives  Thermobel cross bars  Thermobel luxaclair

AGC range – Thermobel Top N+  LT = 78 % - SF = 60 %  Top N+ (ar): Ug = 1,3 – 1,1 W/m²K  Dimensions max: 3210 mm x 6000 mm  Standard thicknesses: 4 - 5 - 6 - 8 - 10 - 12 mm  Processings: laminating

AGC range – Thermobel Top NT  LT = 79 % - SF = 66 %   air: Ug = 1,7 – 1,5 W/m²K ar : Ug = 1,3 – 1,2 W/m²K  Dimensions max: 3210 mm x 6000 mm  t ° out = 0°C t ° in = 20°C Standard thicknesses : 4 – 6 – 8 – 10 mm  sheet = 17.3

°C

AGC range – Thermobel Energy N  LT = 71 % - SF = 42 %  ar: Ug = 1,2 – 1,1 W/m²K  Dimensions max: 3210 mm x 6000 mm   Processings : laminating t ° in = 20°C t ° of inner sheet = 17.3

°C

AGC range – Thermobel Energy NT  LT = 74 % - SF = 45 %  ar: Ug = 1,2 – 1,0 W/m²K  Dimensions max: 3210 mm x 6000 mm   Processings: tempering, laminating t ° of inner sheet = 17.3

°C t ° in = 20°C

AGC range – Thermobel Warm E  Double glazing with Warm Edge spacer  Available with Top N, Energy N, Stopray, …  Maximum dimensions: 3000 x 1800 t ° out = 0°C t ° in = 20°C t ° of inner sheet = 17.3

°C

AGC range – Planibel G  Dimensions max: 3210 mm x 6000 mm  Standard thicknesses : 4 – 6 mm  Transformations: tempering, laminating, bending t ° out = 0°C t ° in = 20°C t ° of inner sheet = 17.3

°C

AGC range – Planibel G  In simple glazing : – LT = 80 % - SF = 71 % – Ug = 3,7 W/m²K  In double glazing : – LT = 74 % - SF = 73 % – Ug (air) = 1,9 – 1,8 W/m²K t ° of inner sheet = 17.3

°C t ° in = 20°C

AGC range - Summary

Raw glass Planibel Planibel Top N Planibel Top NT Planibel Energy N Planibel Energy NT Insulating glazing 4/15 air/4 4/15 ar/4 Thermobel Ug = 2,8 Thermobel Top N+ Ug = 1,4 Thermobel Top N+ Ug = 1,5 Thermobel Energy N Ug = 1,4 Thermobel Energy NT Ug = 1,4 Thermobel Top N+ Ug = 1,1 Thermobel Top N+ Ug = 1,2 Thermobel Energy N Ug = 1,1 Thermobel Energy NT Ug = 1,0 SF 77 64 66 42 45

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Condensation  In the spacer  Glazing to be replaced

Condensation  On the inside surface  Very rare with DG and low-e DG  Sign of interior climate too wet and/or building not enough heated

Condensation  On the outside surface

DGU low e DGU

Condensation

Condensation  On the outside surface  Unavoidable phenomenon, occuring sometimes the morning, after cold nigth without clouds  Is the mark of the very goog insulating level of the glazing  Similar to condenstation on the windscreen of cars

Glass and thermal insulation   Introduction Convection, conduction and radiancy       Single glazing Double glazing Low e double glazing Temperature of surface and comfort AGC range Condensation    Calculation of the Ug-value of a glazing Calculation of the Uw-value of a window Regulation

Calculation of the Ug-value of a glazing (EN 673) Single glazing : 1

Ug

 1

h e



d

  1

h i



h e

= coefficient of surface heat exchange between the wall and the external environment = 1/8 W/(m² K)  

h i

= coefficient of surface heat exchange between the wall and interior environment = 1/23 W/(m² K) d = glass thickness (m);   = thermal conductivity of a glass = 1 W/(m K)

Calculation of the Ug-value of a glazing (EN 673) Double glazing 1

Ug

 1

h e



d

1   1

h s



d

 2  1

h i

with :

h s

 1 e 1 5 , 14  1 e 2  1 

Nu B s

Glass and thermal insulation   Introduction Convection, conduction and radiancy       Single glazing Double glazing Low e double glazing Temperature of surface and comfort AGC range Condensation    Calculation of the Ug-value of a glazing Calculation of the Uw-value of a window Regulation

Calculation of the Uw-value of a window U glazing Spacer U frame

Calculation of the Uw-value of a window

Calculation of the Uw-value of a window (EN ISO 10077-1)

U

w 

A

g 

U

g 

A

f

A

g  

U

f

A

f  

l

g 

ψ

 = 0 to 0,06 ( (metallic spacer) in function of the frame type  = 0.05 (U frame  2.0)  to calculate for Warm edge spacer (EN ISO 10077-2)

Calculation of the Uw-value of a window (EN ISO 10077)  Example of calculation: Comparison between traditional and Warm E spacer Wood Uf = 1.4 W/(m².K) PVC Uf = 1.9 W/(m².K) Alu Uf = 2.0 W/(m².K) Metallic spacer 1.43

1.58

1.70

Warm E Amelioration W/(m².K) % 1.36

0.07

4.9 % 1.51

0.07

4.4 % 1.56

0.14

8.2 % Calculation for window 1.23 x 1.48 m with Thermobel Starlite N 1.2 W/(m².K)

Calculation of the Uw-value of a window (EN ISO 10077)  Exemple of calculation: Influence of the surface of the window and Warm E Dimensions (mm) Surface (m²) Uw aluminium window Metallic spacer Warm E

Amelior. Uw W/(m².K) Amelior. Uw %

910 x 1100 1230 x 1480 1580 x 1900 1.00

1.82

3.00

1.84

1.70

1.60

1.67

1.56

1.49

0.17

0.14

0.11

9.2

8.2

6.8

Glazing Ratio glass/frame : Thermobel Starlite N : 70 / 30

Glass and thermal insulation  Introduction  Convection, conduction and radiancy  Single glazing  Double glazing  Low e double glazing  Temperature of surface and comfort  AGC range  Condensation  Calculation of the Ug-value of a glazing  Calculation of the Uw-value of a window  Regulation

Regulation Most countries have a thermal regulation giving:  maximum Uw-value for the frame or the glass   maximum U-value for the building maximum energy consumption  …

Example: Regulation in Belgium Thermal regulations of the Regions  Uw value of the window to be respected Wallonie Since 09/96 3,5 W/m² K Flandres Since 01/06 Bruxelles Since 01/2000 2,5 W/m² K 2,5 W/m² K + glass 1,6 W/(m²K)  K level to be respected for the building

Example: Regulation in Belgium

Example of U

window U frame U glazing 5,8 2,9 1,8 1,1 Wood 1,8 4,65 2,72 2,01 1,52 PVC 2,8 4.95 3,02 2,31 1,82 Alu 3,5 5,23 3,20 2,43 1,91

Thermal Insulation Solar Control Aesthetic and decoration Acoustic Insulation Safety

Solar control coating Silicone resistant to UV Safety : Laminated glass Acoustic insulation : Laminated glass and assymetric DG Therma insulation low-e coating