Special Infrared Reflective Pigments for Dark Roofs

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

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 andin-situ performance of roofing products • Measure and document improvements in the durability of roofing expected to arise from lower operating temperatures

3. LBNL Steve Wiel(Project Director) SWiel@LBL.gov Hashem Akbari H_Akbari@LBL.gov Paul Berdahl PHBerdahl@LBL.gov Ronnen Levinson RMLevinson@LBL.gov ORNL André Desjarlais yt7@ORNL.gov Bill Miller wml@ornl.gov Project Team

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

5. Identified and CharacterizedPigments w/High Solar Reflectance LBNL • Database online at http://CoolColors.LBL.gov • 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

6. Characterized Nonwhite MixturesCool 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

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

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

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

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

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

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

13. Field-testing at Cavalli Hills Subdivision Fair Oaks, CA ORNL Finished with Low-profile Concrete Tile and Stucco House-3 4987 Mariah Place COOL TILE IR COATING™ 41% reflective COOL TILE IR COATING™ House-1 4979 Mariah Place

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

15. Field-testing at Cavalli HillsSubdivision Fair Oaks, CA ORNL Finished with Painted Metal Shingles and Stucco House-4 4991 Mariah Place South facing roof Ultra Cool 31% reflectance House-2 4983 Mariah Place

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

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

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

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

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

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

23. Atticsim Predicts Attic Ventilation within Range of Literature Data

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

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

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

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

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

29. SUMMARYCOOL 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

30. Cool Colors Project Website • Project information (including copies of this presentation) available online at http://CoolColors.LBL.gov