Low-slope roofs on commercial buildings are exposed to the full amount of horizontal solar radiation. The solar radiation that is absorbed heats the roof surface. The absorbed solar energy, now characterized by the roof surface temperature, is partially remitted in the infrared spectrum. By selecting or coating a low-slope roof so it has a medium to high solar reflectance and a low to high infrared emittance, the desired amount of solar radiation control is achieved. In this paper, background is presented on the development of an interactive estimating tool to assist commercial building owners and/or operators in the selection of a roof. If the low-slope roof is given solar radiation control, the estimating tool indicates the annual savings in operating costs to condition a building under the roof. Alternatively, the tool can give the amount of conventional thermal insulation without radiation control that a roof needs in order to have the same annual energy costs as the roof with the existing amount of conventional insulation and solar radiation control. The tool is part of a fact sheet on solar radiation control for low-slope roofs. The fact sheet is on our Internet web site.

Authors: Thomas W. Petrie, Ph.D.; Jerald A. Atchley; Phillip W. Childs, Andre O. Desjarlais

Citation: Thermal Performance of the Exterior Envelopes of Buildings VIII

Keywords: December, Florida, 2001