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Title: Solar Technologies and the Building Envelope

Abstract

Advances in on-site renewable energy technology have brought the concept of zero-energy buildings within reach. Many single-story residential and commercial buildings have enough favorably oriented roof area to make achieving zero energy technically feasible, assuming no major solar obstructions exist and that energy efficiency has been aggressively implemented in the building design. As the number of stories increases, the potential to have a zero-energy building within the building's footprint decreases. As efficiencies of photovoltaic (PV) cells increase, the potential to have zero-energy buildings increases.

Authors:
; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
915641
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Journal Article
Resource Relation:
Journal Name: ASHRAE Journal
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; COMMERCIAL BUILDINGS; DESIGN; ENERGY EFFICIENCY; ROOFS; WALLS; RESIDENTIAL BUILDINGS; PHOTOVOLTAIC CELLS; Buildings

Citation Formats

Torcellini, P. A., Pless, S. D., Judkoff, R., and Crawley, D.. Solar Technologies and the Building Envelope. United States: N. p., 2007. Web.
Torcellini, P. A., Pless, S. D., Judkoff, R., & Crawley, D.. Solar Technologies and the Building Envelope. United States.
Torcellini, P. A., Pless, S. D., Judkoff, R., and Crawley, D.. Sun . "Solar Technologies and the Building Envelope". United States. doi:.
@article{osti_915641,
title = {Solar Technologies and the Building Envelope},
author = {Torcellini, P. A. and Pless, S. D. and Judkoff, R. and Crawley, D.},
abstractNote = {Advances in on-site renewable energy technology have brought the concept of zero-energy buildings within reach. Many single-story residential and commercial buildings have enough favorably oriented roof area to make achieving zero energy technically feasible, assuming no major solar obstructions exist and that energy efficiency has been aggressively implemented in the building design. As the number of stories increases, the potential to have a zero-energy building within the building's footprint decreases. As efficiencies of photovoltaic (PV) cells increase, the potential to have zero-energy buildings increases.},
doi = {},
journal = {ASHRAE Journal},
number = ,
volume = ,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}
  • Highly reflective roofs can decrease the energy required for building air conditioning, help mitigate the urban heat island effect, and slow global warming. However, these benefits are diminished by soiling and weathering processes that reduce the solar reflectance of most roofing materials. Soiling results from the deposition of atmospheric particulate matter and the growth of microorganisms, each of which absorb sunlight. Weathering of materials occurs with exposure to water, sunlight, and high temperatures. This study developed an accelerated aging method that incorporates features of soiling and weathering. The method sprays a calibrated aqueous soiling mixture of dust minerals, black carbon,more » humic acid, and salts onto preconditioned coupons of roofing materials, then subjects the soiled coupons to cycles of ultraviolet radiation, heat and water in a commercial weatherometer. Three soiling mixtures were optimized to reproduce the site-specific solar spectral reflectance features of roofing products exposed for 3 years in a hot and humid climate (Miami, Florida); a hot and dry climate (Phoenix, Arizona); and a polluted atmosphere in a temperate climate (Cleveland, Ohio). A fourth mixture was designed to reproduce the three-site average values of solar reflectance and thermal emittance attained after 3 years of natural exposure, which the Cool Roof Rating Council (CRRC) uses to rate roofing products sold in the US. This accelerated aging method was applied to 25 products₋single ply membranes, factory and field applied coatings, tiles, modified bitumen cap sheets, and asphalt shingles₋and reproduced in 3 days the CRRC's 3-year aged values of solar reflectance. In conclusion, this accelerated aging method can be used to speed the evaluation and rating of new cool roofing materials.« less
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