Reflecting coatings for the building envelope to mitigate the indoor air temperature during the cooling season

摘要

The use of bright colours for painting the building envelope of buildings is a trademark of vernacular Mediterranean architecture since centuries. On the other side, new buildings are constructed without taking into account these concepts, with increase cooling loads and discomfort conditions for occupants. Old design concepts merged with new technologies and materials can improve the energy performance of buildings during the hot. Reflective coatings and painting for the opaque components of the envelope must have an high reflectance over the solar spectrum, must be easy to clean, have high durability in keeping the original colour and resist to ageing phenomena. The effect of reflective paintings was monitored in two identical rooms of the experimental building Casa Intelligente of ENEA. Indoor and outdoor air temperature, roof surface temperatures on both sides and energy flux through the roof with and without the reflective painting were monitored. This monitoring campaign was very useful to verify the influence of cool roofs to mitigate the indoor temperatures during the hot season and, through the reduced outdoor surface temperatures, to reduce the heat island effect at Mediterranean latitudes.