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Effect of Surface Mass on Roof Thermal Performance
Abstract
The roof of a building is exposed to the most
severe environment that is experienced by any
component of a building envelope. Diurnal peak
surface temperatures of 140 to 185 °F are not
uncommon. The addition of thermal mass to the
exterior surface of the roof should lessen the
severity of the environment that is experienced by
the roof membrane and the roof insulation. The
exterior mass should result in attenuation both of
temperature extremes and of heat flux variations.
It also may result in lowered net heat flow through
the roof. This paper presents some results of a
combined experimental and analytical study to
quantify the effects of surface mass. Measurements
were made on roof test panels that were exposed to
the weather of eastern Tennessee. The test panels
consisted of glass fiber insulation with a modified
bitumen membrane. Experiments were conducted on a
bare panel and on a panels that were loaded with
either concrete pavers or aggregates. A heat
transfer model for the bare panel and the panel with
concrete pavers was developed to calculate the
internal temperatures and heat fluxes using measured
indoor and ambient conditions. The model was
validated by comparing its predictions with measured
values. Following validation, the model was used to
perform a parametric study of the effects of various
levels of surface mass.
Citation
Wilkes, K. E.; Shipp, P. H.; Sanders, J. P. (1988). Effect of Surface Mass on Roof Thermal Performance. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from https : / /hdl .handle .net /1969 .1 /6557.