THE EFFECTS OF SOLAR REFLECTANCE INDEX OF ROOF TILES AND OTHER DESIGN FEATURES ON INDOOR THERMAL COMFORT FOR HOUSING IN TROPICAL CLIAMA TE

Residential buildings in hot humid climate zone are experiencing overheating of
living spaces below the roof as a result of inappropriate selection of roofing systems
and construction materials. Hence, occupants tend to use air conditioning systems
that increase the overall electricity consumption and greenhouse gases emissions i.e.
C02. Therefore, this thesis is mainly intended to develop a cool house for hot humid
climate zone by simply introducing roofing materials with higher Solar Reflectance
Index (SRI). The research methodology adopted in this study consists of experimental
investigations and survey data collection methods and is mainly designed· in three
phases. The first phase consists of a qualitative survey that aims to investigate and
determine the actual condition of roof colors in the existing buildings:·. obtain a
perception of home buyers on implementation of light colored roof tiles, and
determine the understating level, awareness and barriers facing utilizationof light
colored roof tiles with higher SRI in the local construction industry. The second phase
of this research is an experimental investigation conducted on an experimental house
which was constructed within UTP campus. The experimental study is mainly
intended to determine and establish the most important parameters that i~fluence the
SRI values, namely, (I) Roof tile's color, (2) material composition, and (3) the roof
slope and orientation. While the third phase of this study consists of value
engineering, with stress on cost saving and C02 reduction associated with
implementation of light colored roof tiles with emphasize on Putrajaya as a case study
for a green and sustainable city in Malaysia.
The questionnaires data were analyzed using statistical techniques, whilst the
analysis of experimental results was based on the theory of heat transfer and
thermodynamic in buildings (i.e. building physics). The survey analysis results
suggest that 78.5% of the existing buildings in Malaysia have dark colored roof tiles.
In addition, 73.6% of Malaysians are depending on air conditioning systems to improve indoor thermal comfort for housing. The survey has determined that (I) lack
of knowledge, (2) maintenance issues and (3) cultural and religious background are
the main challenges facing implementation of light colored roof tiles especially
"white roof' in Malaysia. Further, the experimental study suggested that "white"
color roof tile is the best in terms of solar reflectivity, flowed by "orange" and "red"
color respectively. Furthermore, regarding the material composition, clay tiles were
found to be cooler than concrete roof tiles, whilst the roof configuration with 32°
sloping in both sides was much better in terms of achieving cooler and healthier
indoor thermal comfort. The overall findings of this research strongly support the
need for implementation of roofing materials with higher SRI values in order to
improve the indoor thermal comfort, reduce electricity consumption in buildings and,
consequently, mitigate greenhouse gases emissions and global warming.