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Bright is the New Black - Multi-Year Performance of Generic High-Albedo Roofs in an Urban ClimateHigh-albedo white and cool roofing membranes are recognized as a fundamental strategy that dense urban areas can deploy on a large scale, at low cost, to mitigate the urban heat island effect. We are monitoring three generic white membranes within New York City that represent a cross-section of the dominant white membrane options for U.S. flat roofs: (1) an ethylene propylene diene monomer (EPDM) rubber membrane; (2) a thermoplastic polyolefin (TPO) membrane and; (3) an asphaltic multi-ply built-up membrane coated with white elastomeric acrylic paint. The paint product is being used by New York City s government for the first major urban albedo enhancement program in its history. We report on the temperature and related albedo performance of these three membranes at three different sites over a multi-year period. The results indicate that the professionally installed white membranes are maintaining their temperature control effectively and are meeting the Energy Star Cool Roofing performance standards requiring a three-year aged albedo above 0.50. The EPDM membrane however shows evidence of low emissivity. The painted asphaltic surface shows high emissivity but lost about half of its initial albedo within two years after installation. Given that the acrylic approach is an important "do-it-yourself," low-cost, retrofit technique, and, as such, offers the most rapid technique for increasing urban albedo, further product performance research is recommended to identify conditions that optimize its long-term albedo control. Even so, its current multi-year performance still represents a significant albedo enhancement for urban heat island mitigation.
Document ID
20120009506
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Gaffin, S. R.
(Columbia Univ. New York, NY, United States)
Imhoff, M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Rosenzweig, C.
(Columbia Univ. New York, NY, United States)
Khanbilvardi, R.
(National Oceanic and Atmospheric Administration New York, NY, United States)
Pasqualini, A.
(Columbia Univ. New York, NY, United States)
Kong, A. Y. Y.
(Columbia Univ. New York, NY, United States)
Grillo, D.
(New York Dept. of Buildings New York, United States)
Freed, A.
(New York Dept. of City Planning New York, NY, United States)
Hillel, D.
(Columbia Univ. New York, NY, United States)
Hartung, E.
(Columbia Univ. New York, NY, United States)
Date Acquired
August 25, 2013
Publication Date
January 1, 2012
Subject Category
Meteorology And Climatology
Report/Patent Number
GSFC.JA.6177.2012
Distribution Limits
Public
Copyright
Public Use Permitted.
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