CONTRIBUTION OF DARK BROWN PAKIS-STEM TOudMITIGATE THERMAL SOLAR IRRADIATION OF AudHEATED ENVIRONMENT

摘要

In the era of global warming issues areal most happening every time and day in manyudcountries, one of the possible to apply brown and white-pakis blocks as high-albedoudheat insulation in the urban cities is on the flat concrete rooftops. The brown-pakisudblocks will absorb much incoming global solar irradiation and emit less longwaveudsolar heat to space; in contrast, the white-pakis blocks could not only handle well theudincoming solar irradiation but it also to lessen the outgoing longwave solar irradianceudby simply emiting much irradiation to atmosphere and performing as insulator to theudflat concrete rooftop. This research is concentrated on the ability of brown Pakis-stemudblocks to reflect less outgoing solar irradiation to space, but to absorb and to emit asudmuch possible of longwave solar heat irradiation. The results of brown Pakis-stemudblocks are proved to reflect an average 18.2 W.m-2 compare to white Pakis blocksud71.7 W.m-2 of outgoing global solar irradiance to atmosphere. The average surfaceudbottom temperature of one-piece brown-Pakis block is 34.8oC compare to 33.9oCudwhite-Pakis block. The contribution of brown-Pakis blocks lessen the over heatedudenvironment, and act as solar irradiation controller and temporary container.