Effect of White and Black Colors on Heat Generation in Polyethylene Geomembranes Exposed to Solar Radiation

摘要

Carbon black is often added to polyethylene geomembranes to improve their ultraviolet resistance. The black color, on the other hand, absorbs most of the solar energy reaching the surface of the geomembrane. The resulting temperature rise induced in the geomembrane is the source of numerous problems in the field. A fine white layer may be added on the exposed surface of the geomembrane to reflect the solar radiation and reduce the geomembrane temperature. This study is aimed at quantifying the difference in heat generation under solar irradiation associated to the presence of this white surface layer. Black and white-surfaced geomembrane specimens were exposed to various laboratory-controlled solar irradiances, using a Xenon-arc chamber modified for the purpose of this project. Temperature was found to be significantly lower in the white-surfaced geomembranes, compared to the black ones, with differences in the range of 10 to 20°C depending on the laboratory controlled solar irradiance.