The Effects of Solar Reflectance Index (SRI) on Roof Tiles for Climate Change Mitigation

Temperature rise is a global phenomenon that has been occuring for a long time. This
is due to the development that occurs everywhere around the world. As human
continue their pursue of the latest technology and the tallest skyscrapper, we tend to
neglect the negative impact it has on the world. Although we cannot dismiss the
importance of developing a nation, we also need to ensure mitigation methods in
order to cope with the ever-rising temperature. We tend to cope with this issue by
using more air-conditioning units in our residents and work places. Green house
gasses emission caused by excessive usage of air-conditioning units is one of the
factors that cause the temperature rise. These gasses are one of the factors of global
warming. Urban Heat Island effect is a huge problem that occurs in rural and urban
areas. It is the effect of excessive heat gain on buildings. During the peak heat of the
day, the temperature of an exposed area might rise up to 50°C [19]. Since the roof
affects more of the heat gain compared to the envelope (walls) of a low-rise building,
we conducted the experiment only on the roofs. A method that can be used to reduce
the usage of air-conditioning units is by choosing light colored roof tiles, which has
high SRI value. A standard white color has the SRI value of 100 while a standard
black color has the SRI value of 0. Solar Emittance and Solar Reflectance affect these
values with both ranging from 0 to 1. By choosing lighter colors, we can manage to
reduce heat absorbtion of our building, especially during the peak heat of the day. The
experiment consists of four roof tile colors, which are white, orange, dark brown and
light grey. The data compared for these colors are the ambient temperature, indoor
temperature, solar irradiation and relative humidity. The experiment was conducted at
an experimental house with the size of 3m x 3m x 2.5m. The instruments used are a
solarimeter, a multimeter and an internal automatic data logger. The duration of each
color was six days.