1. Performance of Exterior Envelopes of Whole Buildings IX
Special Infrared Reflective Pigments Make Dark Roofs Reflect Almost Like White Roofs
Performance of Exterior Envelopes of Whole Buildings IX
December 9, 2004
Ken Loye, Scott Kriner, Bob Scichili
LBNL
ORNL
INDUSTRY
COLLABORATIVE R&D
CEC
DOE
H. Akbari,
P. Berdahl,
R. Levinson,
S. Wiel
W. Miller,
A. Desjarlais
Chris Scruton
Marc Lafrance 1

2. Project Goals Bring cool colored roofing materials to market
Accelerate market penetration of cool metal, tile, wood shake, and shingle products
Measure and document laboratory and in-situ performance of roofing products
Measure and document improvements in the durability of roofing expected to arise from lower operating temperatures 2

3. Project Team LBNL ORNL Steve Wiel (Project Director) SWiel@LBL.gov
Hashem Akbari
Paul Berdahl
Ronnen Levinson
ORNL
André Desjarlais
Bill Miller 3

4. Why are the Cool Roof Color Materials (CRCM) Cooler?4

5. Identified and Characterized Pigments w/High Solar Reflectance
LBNL
Database online at
contact R. Levinson for more info
Describes 233 pigmented CRCM coatings
87 masstones (pure colors)
57 ratio 1:4 tints (new!)
57 ratio 1:9 tints (new!)
32 ratio 1:1 nonwhite mixtures (new!)
Possible future additions
ratio 1:4, 4:1 nonwhite mixtures 5

6. Characterized Nonwhite Mixtures Cool Color Combinations
LBNL
Prepared, characterized nonwhite mixtures
equal volumes of each color paint
Computed Kubelka-Munk absorption and scattering coefficients (K, S)
Coating design software requires
database of pigment properties (ready)
optimization algorithm (to be chosen)
model for absorption, scattering of mixture
Simple volumetric model: each component contributes volumetrically to absorption K and scattering S of mix
Kmix = ∑ ci Ki
Smix = ∑ ci Si
where ci = volume fraction of component i 6

7. Developing Prototype Cool Dark Brown Shingle (representative image)
LBNL
ORNL
Matches standard dark brown shingle
Solar reflectance SR > 0.2
Next version may achieve SR > 0.25 (Energy Star) 7

8. CooL Tile IR CoatingTM Applied to Concrete Tile
ORNL
LBNL
COOL TILE IR COATING™ technology was developed by Joe Reilly of American Rooftile Coatings 8

9. COOL CEDAR SHAKES POSE POTENTIAL IMPROVEMENT IN FIRE RATING
ORNL
LBNL
Cedar Shake roof 16-yrs of exposure
John Goveia (TRS) Martinez, CA 9

10. COOL PAINTED METAL WITH PVDF “polyvinylidene fluoride” base coat
ORNL
LBNL
SR boosted a factor of 6 greater than dark roofing 10

11. Accelerated Weathering to Check Pigment Fade Resistance
ORNL
LBNL
Total Color Difference measure E 11

12. Three Years of Field Exposure in Florida Shows Improved Fade Resistance
ORNL
Painted PVDF metals 12

13. Field-testing at Cavalli Hills Subdivision Fair Oaks, CA
ORNL
Finished with Low-profile Concrete Tile and Stucco
House Mariah Place
COOL TILE IR COATING™
41% reflective
COOL TILE IR COATING™
House Mariah Place 13

14. Cool Coating on Concrete Tile Reduces Heat Flux Through Ceiling
ORNL
Drops Attic Temperature ~4oC (7oF) at Solar Noon 14

15. Field-testing at Cavalli Hills Subdivision Fair Oaks, CA
ORNL
Finished with Painted Metal Shingles and Stucco
House Mariah Place
South facing roof
Ultra Cool 31% reflectance
House Mariah Place 15

16. Cool Coating Reduces Heat Flux Through South Facing Roof Deck
ORNL
Painted Metal Roofs 16

17. Materials Testing at CA Exposure Sites
ORNL
Clay and Painted Metal exposed for 1½ years 17

18. Rawhide and Slate Bronze Painted Metal Solar Reflectance
ORNL
Climatic zone affects loss of reflectance 18

19. Airborne Pollutants Appear to have a Strong Effect on the Loss of Reflectance
ORNL
Loss of reflectance changes with roof slope
White Buff Clay Tile 19

20. 20

21. Mission Tiles Yield the Lowest Roof Heat Flux and Attic Air Temperature
Synergism observed between SR and batten – counter batten venting 21

22. AtticSim tool predicts thermal performance of residential attics
Reflectance and emittance
Ceiling and roof insulation
Attic Ventilation
Roof Orientation
Roof slope
Roof thermal mass
Moisture (external and internal)
Deck ventilation 22

23. Atticsim Predicts Attic Ventilation within Range of Literature Data23

24. AtticSim Validation for Direct Nailed Shingle Roof tested on ESRA24

25. Potential Energy Savings Gained for Painted Metal Implementing CRCMs
 R-19 Ceiling Insulation (IECC, 2000) 25

26. In more moderate climates the heating load penalty offsets the cooling energy savings
CRCMs do not yield an energy savings in cold climates 26

27. Savings based on the incremental gains over an SR08E80 roof with R-19 insulation in Dallas
electricity $0.10 per kWh; natural gas $10.00 per 1000 ft3 27

28. Savings are based on the incremental gains over an SR08E80 roof with R13 insulation in Miami
electricity $0.10 per kWh; natural gas $10.00 per 1000 ft3 28

29. SUMMARY COOL ROOF COLOR MATERIALS
Characterized and Identified “Cool Colors”
Web database describes 233 pigmented coatings
Developing engineering methods to apply them for optimum reflectance
Demonstration sites proving energy savings generated by “Cool Colors”
Tile, Metal, Asphalt shingle, Cedar Shake
Attic Assembly on ESRA at ORNL
Field exposure sites in California
Benefits from infrared pigment study
Energy savings for homeowners and businesses
Mitigate CO2 emissions polluting environment
Utilities will cut peak demands 29

30. Cool Colors Project Website
Project information (including copies of this presentation) available online at 30