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Title: Measured energy savings of light colored roofs: Results from three California demonstration sites

Abstract

Measured data and computer simulations have demonstrated the impact of roof albedo in reducing cooling energy use in buildings. Savings are a function of both climate and the amount of roof insulation. The cooling energy savings for reflective roofs are highest in hot climates. A reflective roof may also lead to higher heating energy use. Reflective coatings are also used in commercial buildings to protect the roofing membrane, and hence, maintain and prolong the useful life of the roof. Reflectivity of coatings changes with weathering and aging which in turn could have an effect on building cooling-energy savings. For that reason, reflective roof coatings are not primarily marketed for their energy savings potential. To monitor the field performance of reflective coatings, the authors initiated a demonstration project where three commercial buildings in California were painted with light-colored roof coatings. The buildings are two medical care centers and one drug store. At all sites, the roof reflectance, both fresh and aged, and cooling energy use were monitored. In addition, they measured temperature throughout the roof systems and inside the conditioned space. In the monitored buildings, increasing the roof reflectance from an initial value of about 20% to 60%, dropped the roofmore » temperature on hot summer afternoons by about 45 F. Summertime standard-weekday average daily air-conditioning savings were 18% (198 kWh) in the first medical office building, 13% (86 kWh) in the second medical office building, and 2% (13 kWh) in the drug store. The overall u-value of the roofs had dictated the impact of roof reflectance.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab., Environmental Energy Technologies Div., Berkeley, CA (United States)
Sponsoring Org.:
Environmental Protection Agency, Washington, DC (United States)
OSTI Identifier:
674928
Report Number(s):
LBNL-41907; CONF-980815-
ON: DE98057493; TRN: AHC29820%%392
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: 1998 ACEEE summer study on energy efficiency in buildings, Pacific Grove, CA (United States), 23-28 Aug 1998; Other Information: PBD: Jun 1998
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ROOFS; ALBEDO; REFLECTION; COOLING LOAD; COMMERCIAL BUILDINGS; ENERGY CONSERVATION; COST BENEFIT ANALYSIS

Citation Formats

Akbari, H, Gartland, L, and Konopacki, S. Measured energy savings of light colored roofs: Results from three California demonstration sites. United States: N. p., 1998. Web.
Akbari, H, Gartland, L, & Konopacki, S. Measured energy savings of light colored roofs: Results from three California demonstration sites. United States.
Akbari, H, Gartland, L, and Konopacki, S. Mon . "Measured energy savings of light colored roofs: Results from three California demonstration sites". United States. https://www.osti.gov/servlets/purl/674928.
@article{osti_674928,
title = {Measured energy savings of light colored roofs: Results from three California demonstration sites},
author = {Akbari, H and Gartland, L and Konopacki, S},
abstractNote = {Measured data and computer simulations have demonstrated the impact of roof albedo in reducing cooling energy use in buildings. Savings are a function of both climate and the amount of roof insulation. The cooling energy savings for reflective roofs are highest in hot climates. A reflective roof may also lead to higher heating energy use. Reflective coatings are also used in commercial buildings to protect the roofing membrane, and hence, maintain and prolong the useful life of the roof. Reflectivity of coatings changes with weathering and aging which in turn could have an effect on building cooling-energy savings. For that reason, reflective roof coatings are not primarily marketed for their energy savings potential. To monitor the field performance of reflective coatings, the authors initiated a demonstration project where three commercial buildings in California were painted with light-colored roof coatings. The buildings are two medical care centers and one drug store. At all sites, the roof reflectance, both fresh and aged, and cooling energy use were monitored. In addition, they measured temperature throughout the roof systems and inside the conditioned space. In the monitored buildings, increasing the roof reflectance from an initial value of about 20% to 60%, dropped the roof temperature on hot summer afternoons by about 45 F. Summertime standard-weekday average daily air-conditioning savings were 18% (198 kWh) in the first medical office building, 13% (86 kWh) in the second medical office building, and 2% (13 kWh) in the drug store. The overall u-value of the roofs had dictated the impact of roof reflectance.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {6}
}

Conference:
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