Modeling The Thermal Performance Of Passive
Roofing Systems In A Tropical Climate
Author(s)
S. Tong & H. Li
Abstract
In order to curb the space cooling load in buildings in summer, various passive
technologies have been applied on the roofs, including cool paint, roof
ventilation, and mass/reflective insulation. It is highly desirable to evaluate the
potential benefits of applying these passive technologies on the roofs. In this
work, the Complex Fast Fourier Transform (CFFT) method is introduced to
predict the ceiling temperature and heat gain of multilayer roofs. A parameter
study based on the CFFT model is conducted to investigate the impacts of
rooftop surface reflectivity and insulation thickness on the thermal performance
of roofs. It is concluded that, compared with the least reflective roofs of solar
reflectivity 0.1, increasing the solar reflectivity of roof by 0.1 cuts down the
daily heat gain by 4%, 5% and 7% respectively, when the indoor temperatures
are set to 25°C, 22°C to 19°C. In addition, increasing the thickness of basic 15-
cm unventilated roof by 5 cm contributes to reduce the daily heat gain by 6% on
average. The heat gain reductions obtained by applying various passive
technologies on roofs subjected to typical Singapore climate are evaluated,
including cool paint, roof ventilation, expanded polystyrene (EPS) foam and
radiant barrier (RB). The individual uses of the passive roofing technologies
contribute to reduce the daily roof heat gain by 36~84%.
Keyword: passive roofing system, transient roof temperature, tropical climate,
Complex Fast Fourier Transform (CFFT) method.
Keywords
Keyword: passive roofing system, transient roof temperature, tropical climate,
Complex Fast Fourier Transform (CFFT) method.
Related Book
Other papers in this volume
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