Accelerated Aging of Roofing Materials (the “Advanced Surfaces” project) · 2018-06-26 ·...
Transcript of Accelerated Aging of Roofing Materials (the “Advanced Surfaces” project) · 2018-06-26 ·...
Accelerated Aging of Roofing Materials(the “Advanced Surfaces” project)
Paul Berdahl, Ronnen LevinsonHugo Destaillats, Tom Kirchstetter, Mohamad Sleiman et al.
Heat Island Group, Atmospheric Sciences Department
Building Technologies Program
CRRC Membership MeetingReno NevadaJune 9, 2011
1
Heat Island Group, Lawrence Berkeley National Laboratory2
Hugo Destaillats Ronnen Levinson
Thomas Kirchstetter Paul Berdahl Mohamad Sleiman Haley Gilbert Mike Spears
Hashem Akbari Bill MillerAndre Desjarlais
LBNL team
Concordia University
ORNL
“Advanced Surfaces” Team
George Ban-Weiss
Heat Island Group, Lawrence Berkeley National Laboratory33
Replacing a dark roof with a cool (highly reflective) roof can
Cool roofs
Reduce annual cooling energy use by 5-20% (Levinson et al. 2005)
Lower the outside air temperature and the rate of smog formation (Rosenfeld et al. 1998; Akbari et al. 2001)
Delay global warming (10 tonnes of CO2 offset by 100 m2 of white roofing)(Menon et al. 2010; Akbari et al. 2009; Oleson et al. 2010)
Heat Island Group, Lawrence Berkeley National Laboratory4
MOTIVATION• Advance the production and
adoption of high-performance, soiling-resistant roofing products
OBJECTIVES• Create an accelerated soiling
and weathering method for roofs and PVs
• Develop international standards for accelerated exposure
• Learn how to make roofsand PVs stay clean
Overview
Heat Island Group, Lawrence Berkeley National Laboratory5
Background
• Recent ORNL/LBNL work on soiling of inert PVDF coatings in California– Weak soil adhesion leads to clean materials after rain– Dusty summers are followed by rainy winters– Solar reflectance varies with the season
• Weathering of asphalt shingles– Material changes in first year increase reflectance– Changes thereafter just due to soiling
Heat Island Group, Lawrence Berkeley National Laboratory6
PVDF white sample at Shafter, CAat 1 year (August)
Heat Island Group, Lawrence Berkeley National Laboratory7
Soiling reduces reflectance of light surfaces and increases the reflectance of dark surfaces (ORNL / LBNL California study)
Initial reflectance (thousandths)
100 200 300 400 500 600 700
Ref
lect
ance
cha
nge
(thou
sand
ths)
-250
-200
-150
-100
-50
0
50
100
150
Colton, CA, 1 yearPVDFa = 0.14r = 0.165
[Here the parameters a and rare the solar absorptance and solar reflectance of the soil layer.]
Heat Island Group, Lawrence Berkeley National Laboratory8
Soiling reduces reflectance … continued
• Zero crossing occurs at R* = 0.2 to 0.4– Brightness of local soil– Largest values in southern desert
• PVDF accumulates less soil than tile due to reduced adhesion
• Steeper tilt - less soil• More soil/dust in dry southern California• Seasonal pattern of dusty summers and
wet winters
Heat Island Group, Lawrence Berkeley National Laboratory9
Close up of unweathered and weathered shingles
Heat Island Group, Lawrence Berkeley National Laboratory
Asphalt on black shingle new (left) and weathered (right)
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Heat Island Group, Lawrence Berkeley National Laboratory11
Reflectance of 8 reflective asphalt shingle panels, beginning spring, 2008
Months of exposure (Berkeley)
0 6 12 18 24
Sol
ar re
flect
ance
(tho
usan
dths
)
220
240
260
280
300
320
340
360
C9 cool bright whiteC14 cool light tanC6 cool tanC7 cool siennaC12 whiteC8 cool blue-grayC16 cool weathered woodC1 standard whiteC5 cool chestnut
Heat Island Group, Lawrence Berkeley National Laboratory12
Effect of aging on solar reflectance (i/ii)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
FLORIDAno change
CA Title 24running mean
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0Ag
ed s
olar
refle
ctan
ceInitial solar reflectance
ARIZONA no change
CA Title 24
running mean
California Title 24 provisional aged solar reflectance formula:
20.070.020.0 iT24a,
Initial SRSR of an opaque soil layer resistance to soiling
Heat Island Group, Lawrence Berkeley National Laboratory13
Effect of aging on solar reflectance (ii/ii)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
Factory-appliedcoating
FLORIDA
CA Title 24
running mean
no change
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
Field-appliedcoating
FLORIDACA Title 24
no change
running mean
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
Metal
FLORIDA
no change
CA Title 24
running mean
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
Modifiedbitumen
FLORIDA
no change
CA Title 24
runningmean
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
Single-ply membrane
FLORIDA
no change
CA Title 24
running mean
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Aged
sol
ar re
flect
ance
Initial solar reflectance
Tile
FLORIDA
running mean
CA Title 24
no change
Heat Island Group, Lawrence Berkeley National Laboratory14
Roofing products used in our study
We screened 100 roofing materials from 40 suppliers Selection of different materials:
Asphalt shinglesConcrete tilesClay tilesSingle-ply membraneMetal roofingFactory applied coatings
Field applied coatings
Selection criteria included diversity of products & colors, market presence, sample uniformity and availability of aged samples
coatings
shingles concrete tiles metal roofing
clay tiles single-ply membrane
Heat Island Group, Lawrence Berkeley National Laboratory15
Natural weathering of roofing products
hot and dry(Arizona)
hot and humid(Florida)
temperate(Ohio)
Samples naturally aged at 3 weathering sites
Samples collected and characterized quarterly
JANUARY APRIL JULY OCTOBER
2011
2012
2013
Florida
Heat Island Group, Lawrence Berkeley National Laboratory16
Laboratory accelerated soiling tests
Outline:
1. Develop spraying system for application of soiling agents
2. Test with soot, salts, organic matter and dust surrogates
3. Compare deposition of soiling constituents on roofing materials
4. Validate by comparing with naturally aged samples
5. Validate by comparing with roadway tunnel-soiled samples
Dust28 – 66%
Soot4 – 12%
POM8 – 36 %
Salts18 – 27%
Dust53%
Salts23%
POM18%
Soot6%
Average composition (in mass) of soiling components from atmospheric deposition
POM: Particulate Organic Matter
Favez et al, 2006 – Atmos. Environ
Heat Island Group, Lawrence Berkeley National Laboratory17
Soiling surrogates prepared in our lab
Soot hydrosolSalts Organics Dust
Ozone
Heat Island Group, Lawrence Berkeley National Laboratory18
Accelerated aging at LBNL
spray nozzleCompressed spraying vessel
samples
Prototype system for application of soiling agents to roofing samples
Unsoiled Soiled
soiling mixture
IR lamp (drying)
Weatherometer
Heat Island Group, Lawrence Berkeley National Laboratory19
Effect of each soiling constituent on SR
Humic acid
Soot
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1,0
250 500 750 1000 1250 1500 1750 2000 2250 2500
Ref
lect
ance
Wavelength (nm)
UnsoiledSoiled with SaltsSoiled with DustSoiled with humic acidSoiled with soot
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
UnsoiledLab soiled with saltsLab soiled with dustLab soiled with humic acidLab soiled with soot
Organicsorganics
Heat Island Group, Lawrence Berkeley National Laboratory20
Optimization of soiling mixture to mimic soilingof roofing products in hot & humid climate
Can organics mimic microbiological growth?
Very good match between our lab soiled (1 min) and 3 years aged roofing membrane in Florida
organics
Heat Island Group, Lawrence Berkeley National Laboratory21
Summary
Developing reliable approach for accelerated soilingof roofing materials
Good correlation between the loading of soiling constituents and the loss of solar reflectance (ρa/ρi)
Tunable to mimic soiling in dry, temperate, hot & humid climates
Validated with naturally aged and tunnel-soiled samples in preliminary tests (further validation underway)
Straightforward method that can be readily adopted by industry
Established a large network of industrial collaborators and other stakeholders to support implementation
Heat Island Group, Lawrence Berkeley National Laboratory22
Ongoing work
– Integrate laboratory weathering and soiling
– Examine seasonal effects in natural weathering
– Validate our laboratory process with naturally aged samples
– Form new ASTM, ISO task groups
– Convene summer 2011 workshop at LBNL to build momentum for soiling standard
– CRADA with Dow Chemical
Heat Island Group, Lawrence Berkeley National Laboratory23
Thursday, July 28 –Friday, July 29, 2011
Berkeley, California USA
http://coolroofs2011.lbl.gov
Agenda
• Accelerated soiling and weathering of roofing materials
• Incorporation of accelerated aged ratings into policies, standards and rating systems
• Benefits of soiling- and weathering-resistant cool urban surfaces
• Development of next generation cool roofing (and pavement)
• Marketplace trends in cool roofing
Intended audience
• Roofing industry • Weathering firms • US DOE, US EPA, CEC, CARB• US CRRC, EU Cool Roof Council,
international rating bodies (e.g., China, India, Japan)
• ASTM, ASHRAE, ISO, US Green Building Council
• Utilities and other stakeholders
Heat Island Group, Lawrence Berkeley National Laboratory24
CRADA with ORNL and Dow Chemical
Goal: facilitate development of advanced elastomeric coating technology
Target: 75% aged solar reflectance, boosting energy savings by 50%
DOW will develop new polymers and coating formulations
ORNL/LBNL will evaluate retention of solar reflectance in natural and accelerated aging tests
Heat Island Group, Lawrence Berkeley National Laboratory25
Acknowledgments
• Funding: – U.S. Department of Energy (DOE)
• Program Manager: Marc LaFrance
• Our industrial partners• Experiments and measurements
– David Francois– Tosh Hotchi– Amandine Montalbano– Chelsea Preble – Mike Spears – Vasileia Zormpa