Estimating Thermal Performance of Cool Colored Paints

摘要

The purpose of the study is to investigate the thermal performance of cool acrylic colored paints,composed with infrared reflective pigments,in comparison to conventional acrylic colored paints of similar colors (white,brown and yellow) applied over fiber cement corrugated roof sheets.The properties evaluated were: the color according to ASTM D 2244-89 in free films; the UV/VIS/NIR reflectance according to ASTM E 903-96 and the thermal performance by exposition to infrared radiation emitted by a lamp.The surface temperature of the specimens was measured with thermocouples connected to a data logging system.The last two tests were performed on unpainted and painted fiber cement roof sheets specimens.The collected data demonstrated that the cool colored paints formulations show NIR reflectance significantly higher than conventional paints of similar colors and the surface temperatures of cool paints were more than 10°C lower than conventional paints when exposed to infrared and solar radiations.The study showed that the cool paints have potential to improve the thermal comfort conditions inside the building and contribute to saving energy in air conditioning.