CONTRIBUTION OF DARK BROWN PAKIS-STEM TO MITIGATE THERMAL SOLAR IRRADIATION OF A HEATED ENVIRONMENT

In the era of global warming issues areal most happening every time and day in many
countries, one of the possible to apply brown and white-pakis blocks as high-albedo
heat insulation in the urban cities is on the flat concrete rooftops. The brown-pakis
blocks will absorb much incoming global solar irradiation and emit less longwave
solar heat to space; in contrast, the white-pakis blocks could not only handle well the
incoming solar irradiation but it also to lessen the outgoing longwave solar irradiance
by simply emiting much irradiation to atmosphere and performing as insulator to the
flat concrete rooftop. This research is concentrated on the ability of brown Pakis-stem
blocks to reflect less outgoing solar irradiation to space, but to absorb and to emit as
much possible of longwave solar heat irradiation. The results of brown Pakis-stem
blocks are proved to reflect an average 18.2 W.m-2 compare to white Pakis blocks
71.7 W.m-2 of outgoing global solar irradiance to atmosphere. The average surface
bottom temperature of one-piece brown-Pakis block is 34.8oC compare to 33.9oC
white-Pakis block. The contribution of brown-Pakis blocks lessen the over heated
environment, and act as solar irradiation controller and temporary container.