Single and Dougle Layered Vacuum Insulation Panels of the ......square shape (500 x 500 mm) optimal...

Foto SunnyWatt Regensdort 2010 Kämpfen www.vacuspeed.ch/referenz

Single and double layered vacuum insulation panels of the same thickness in comparison

Samuel Brunner Laboratory for Building Science and Technology

SunnyWatt 2009 von kämpfen für architektur AG

Source www.vacuspeed.ch/referenz Foto SunnyWatt von kämpfen für architektur AG 2009

square shape (500 x 500 mm)

optimal for thermal conductivity measurements in Guarded hot plate λcop = 4.1 mW/(m·K)

VIP of a major manufacturer:

BEST3 2.4.2012 S. Brunner, Empa 2

In English units 0.028 BTU-in/ft²-hr-F 35 R per inch

Two different cross sections:

Aging – Determination of core properties TABLE 6: Measurement on VIP as delivered with 500 mm x 500 mm and nominal thickness 15, 20, 30 mm TABLE 7: VIP resealed with higher internal pressure, TABLE 8: VIP resealed to get the moisture dependence

Measurement number

Internal pressure Thickness

Thermal conductivity λ R1-dim

mbar mm mW/(m K) (m2 K)/W 1 1.8 / 2.4 16.1 / 16.1 4.1 3.9 2 1.2 / 1.3 21.7 / 21.7 4.0 5.4 3 1.7 / 1.2 31.5 / 31.6 3.9 8.1

(Eq.4)

Measurement number

Internal pressure λ mbar mW/(m K) W/(m K bar)

4 58 5.3 0,021

dpdp /λλ =

Measurement number

Moisture increase (ΔXw)

Internal pressure λ

M-% mbar mW/(m K) mW/(m K M-% ) 5 3.06 16 4.8 0,23

dXwdXw /λλ =


( )( )τλλλλλλ tXtptt eqwXwap −−⋅+⋅⋅+≅∆+= exp1)()( ,%900

To compare with Graph ZAE data

To compare with Graph ZAE data

Aging – Determination of envelope properties

VIP size mm

increase in internal pressure,

mbar / year

moisture related weight increase %-mass / year

time constant of moisture

equilibration τ, years

250 x 250 x 10 250 x 250 x 10 250 x 250 x 10 Mean :

3.0 2.9 2.9

2.9

0.04 0.05 0.06

0.05

51

500 x 500 x 15 500 x 500 x 15 500 x 500 x 15 Mean :

1.8 1.6 1.7

1.7

0.04 0.03 0.03

0.03

85

500 x 500 x 20 500 x 500 x 20 Mean :

1.6 1.6

1.6

0.027 0.017

0.022

117

500 x 500 x 30 500 x 500 x 30 Mean :

1.7 1.7

1.7

0.018 0.021

0.020

128

p u


Aging - Predicted values for a single layer at 23°C / 50% r.H. for 25 years

VIP Size [mm] 250x250x10

500x500x15

500x500x20

500x500x30

Predicted values Internal pressure ptotal [mbar] Moisture content u [%-mass]

76

1.0

45

0.7

42

0.5

44

0.5 Thermal conductivity λcop,25y [mW/(m·K)] without thermal bridge effect for this pyrogenic SiO2 based core

6.0

5.3

5.3

5.3

Psi – value with / without seal [mW/(m·K)] 25 / 15 16 / 11 14.7 / 10 12 / 8

Effective thermal conductivity λeff, 25years [mW/(m·K)] incl. thermal bridge effect

9.2 6.9 7.2 7.7

BEST3 2.4.2012 S. Brunner, Empa 5 starting with = 4.4 mW/(m K)

%90λ

Predicted values for other dimensions

starting with = 4.4 mW/(m K)

VIP size

mm

Thermal conductivity

λcop,25y [mW/(m K)] without thermal

bridge effect

Effective thermal conductivity

λeff, 25y [mW/(m K)] incl. thermal bridge

effect 1000 x 600 x 10 5.1 6.1 1000 x 600 x 20 5.0 6.3 1000 x 600 x 40 5.1 6.4

1000 x 300 x 20 5.3 7.2

500 x 600 x 20 5.2 7.0 500 x 300 x 20 5.5 8.0

%90λ


Considering production deviation

= 4.1 mW/(m K) center of panel thermal conductivity = 4.4 mW/(m K) 90% fractile (of at least 10 measurements)

~ 4.5 mW/(m K) 90% fractile with 90% reliability to be in line with standards EN 13162 to EN 13171 of conventional insulation starting with 4.4 mW/m·K, calculated from the manufactures statistic and checked by 3 own measurements.

copλ


%90λ

%90λ

%90%,90λ

VIP edge without sealing

* Interpolated value. Fits to the 0.0092 ± 0.0016 published in GhaziWakili2004 on the same nominal laminate with 3 times 100 nm aluminum and total thickness about 98 to 100 µm

Thickness

Measured effective thermal

conductivity

Ther-mal

bridge type

Ψ joint Ψedge, without

seal

mW/(m·K) W/(m·K) W/(m·K) 15 mm 5.5 Psi 1 0.022 0.011 20 mm 0.009* 30 mm 5.5 Psi 1 0.016 0.008 40 mm 5.5 Psi 1 0.009 0.005

± ca 0.1

rectangular shape VIP metallized barrier 3x 100nm aluminum.


VIP Edge with sealing

Extra produced on request of Empa with seal on the long edge.

Thickness

Measured effective thermal

conductivity

Thermal bridge type

Ψ joint

Ψ edge, with seal

mW/(m·K) W/(m K) W/(m K) 15 mm 6.3 Psi 2 0.032 0.016 20 mm 0.0147 * 30 mm 6.7 Psi 2 0.023 0.012 40 mm 6.8 Psi 2 0.017 0.009

Average with/without seal: Ψ15 mm, edge = 0.014 W/(m K) Ψ20 mm, edge = 0.012 W/(m K) * Ψ30 mm, edge = 0.010 W/(m K) Ψ40 mm, edge = 0.007 W/(m K) * value obtained by interpolation


Double layered VIP

Figure 4: single joint in one layer, no joint in the second layer measuring zone (blue) symmetrical assembly of two samples (ISO 8302)


Bild0049.jpg

Figure 5: single joint in one layer, no joint in the second layer A typical gap between the VIP cores can be seen at this 40mm + 40mm situation.

Averaged over all thicknesses

Length related Psi-value ψB [W/m·K]

0.0025 ± 0.0015

Double layered VIP


Double layered VIP Center-of-panel values:


Thickness

Measured thermal

conductivity λ eff, A

mW/(m·K) 15 mm 4.1 20 mm 4.0 25 mm 4.4 30 mm 3.9 40 mm 4.0

4.1 ± 0.2

Double layered VIP Result for situation D:


Thick-ness

Measured thermal

conductivity Length related

Psi-value ψB mW/(m·K) [W/m·K]

20 mm 0.0060 ± 0.0002 0.0125 ± 0.0018 25 mm 0.0059 ± 0.0002 0.0075± 0.0014 30 mm 0.0062 ± 0.0002 0.0096 ± 0.0012

same values as for the single layer measurements (within the scattering of production)

Double layered VIP Example 1:

Area 6 x 3 m = 18 m2

Lower Layer 30 VIP with 1000 x 600 x 20 mm Upper layer 20 VIP with 1000 x 600 x 20 mm + 10 VIP with 1000 x 300 x 20 mm + 8 VIP with 500 x 600 x 20 mm + 4 VIP with 500 x 300 x 20 mm Psi D / 2 0.00625 W/(m·K) 18 m (Perimeter of total area) Psi B 0.0025 W/(m·K) 87 m (Joints)

Result: λeff. 25 years, including edge effects = 6.0 mW/(m·K) for a staggered double layer 20 + 20 mm VIP

Without aging λeff., including edge effects = 5.1 mW/(m·K) BEST3 2.4.2012 S. Brunner, Empa 14

Comparison staggered double layered VIP (20m+20mm) with a corresponding single layer (40 mm)

Total thickness

VIP thickness

Small area 6 x 3 m

Large area 10 x 20 m

λeff. 25 years, including edge effects mW/(m·K)

staggered double layered 40 mm 20mm +20mm

6.0 5.9

single layer (40 mm) 40 mm 40 mm 6.4 6.4

non-staggered double layer 40 mm

20mm +20mm

6.3 6.3


In English units 5.9 mW/(m·K) = 0.040 BTU-in/ft²-hr-F = 25 R per inch

Home take message

• Only about 1/3 of the edge effect can be reduced by staggering the VIP.

• staggered double layer has better performance : VIP size (mm) λeff, 25 year, incl. thermal bridge effect

1000 x 600 x 20 staggered double layer 5.9 mW/(m·K) 1000 x 600 x 40 single layer 6.4 mW/(m·K) Reminder: staggered double layer has a better behaviour regarding a VIP failure compared to a single layer


Discussion

• higher psi –value than published by several other authors (based often on simulation only)

• former recommendation to use preferable thick VIP (>15 mm) is no longer valid for several manufacture

• Aging related parameters are improved by several VIP producer since the IEA Annex39 report (2005)


Acknowledgements Thomas Stahl, Karim Ghazi Wakili at Empa Swiss Federal Office of Energy (SFOE), CCEM and CTI Porextherm (manufacturer) and ZZ Wancor (distributor)


Thermal conductivity - including thermal bridge effect 3x metallised, 23°C / 50% r.F.


Foto Eulachhof Winterthur 2007 Source www.vacuspeed.ch/referenz

other thermal bridges on the dominating VIP application (over 90% of the Swiss market)

thermal bridge catalog for VIP (in German only, 2009 ) http://www.energie-plattform.ch/hlwd/forschung-entwicklung/vip-waermebruckenkatalog_schlussbericht.pdf

http://www.energie-plattform.ch/hlwd/forschung-entwicklung/vip-waermebruckenkatalog_schlussbericht.pdf



Foto Eulachhof Winterthur 2007 www.vacuspeed.ch/referenz








thermal bridge catalog for VIP (in German only ) http://www.energie-plattform.ch/hlwd/forschung-entwicklung/vip-waermebruckenkatalog_schlussbericht.pdf


Source www.vacuspeed.ch/referenz Foto SunnyWatt von kämpfen für architektur AG 2009







Aging at other temperatures (as in Simmler2005, as well as with the temperature profile of a year )


• Laboratory aging of VIP with fumed silica core, metallised polymer laminate barrier ( aging by permeation )

0

5

10

15

20

25

30

35

0 100 200 time [days]

inte

rnal

pre

ssur

e [m

bar]

80°C 80%r.H const. climate

80°C 80%r.H 8h / 25°C 50%r.H 4h cyclic climate

80°C dry (ca. 4%r.h.) 30°C 90%r.H

with eye guiding line

0% 1% 2% 3% 4% 5% 6% 7%

0 50 100 150 200 time [days]

Wat

er v

apor

upt

ake

[wei

ght-

%]

….

At 65

C 75%r.h At 23

C 50% r.h

Temperaturstatistik VIP aussenTerassendämmung, Klima Kloten DRY

0

100

200

300

400

500

600

700

800

-20 -10 0 10 20 30 40 50Temperatur T, °C

Anz

. Stu

nden

010002000300040005000600070008000900010000

Sum

me

Std

. mit

TVIP

< T

Temperaturverlauf VIP innen / aussenTerrassendämmung, Klima Kloten DRY

-30

-20

-10

0

10

20

30

40

50

0 2000 4000 6000 8000Stunde, Nr.

Tem

pera

tur,

°CAging with the temperature profile of a year VIP aging for terrace roof as in Brunner2008 in Journal Vacuum


• Result:

• Inner pressure increase + water take up-> λ ≅ 0.008 W/(m K) • prerequisite: not an other failure mode

Label VIP inner side VIP outer side T max °C 22.5 44.1 T average °C 21.5 11.9 T effective (Arrhenius) °C 21.3 16.0 ∆ pi/∆t mbar/a 2.5 1.6

VIP aging for terrace roof (measurements)


Published in : • Brunner, S, Simmler H., In situ performance assessment of vacuum insulation panels in a flat roof construction, Vacuum 82

(2008) 700–707

Pressure increase rate VIP 50x50x2 cm3

01234567

0 300 600 900 1200

time after installation, days

p a, m

bar/a

Mean±2Stdev (90%)Mean±Stdev (66%)samplesYearly marks

0

2

4

6

8

10

0 5 10 15 20 25Time, years

Ther

mal

con

duct

ivity

, 10 -3

W/(m

K) moisture accumulation (linear)

moisture accumulationpressure increaseinitial fumed silica core

( )( )τλλλλ tXtpt eqwXwap −−⋅+⋅⋅+≅ exp1)( ,0

long-term value for thermal conductivity

Pressure increase rate VIP 50x50x2 cm3

01234567

0 300 600 900 1200 1500 1800 2100

time after installation, days

p a, m

bar/a

Mean±2Stdev (90%)Mean±Stdev (68%)samplesYearly marks

Al-layers without any visible change (outermost one) 2009

25’000 m2/year in Switzerland

Single and Dougle Layered Vacuum Insulation Panels of the ......square shape (500 x 500 mm) optimal...

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