Paper No 314: Optical properties and influence of reflective coatings on the energy demand and thermal comfort in dwellings at Mediterranean latitudes

Climatic conditions affect shape, colour, geometry and lay-out of buildings. The vernacular Mediterranean architecture was characterised, among other passive techniques, by light colours to minimise solar gains through the opaque components of the building envelope. Actual building design and construction often forget such old bioclimatic approaches, delegating the comfort conditions to artificial systems. The energy consumption increase in the residential sector witnesses this problem, due to the high penetration of air conditioning systems. Ancient concepts, merged with innovative technologies, are hence necessary today. Reflective coatings can reduce the cooling loads with an effective solar control on the building envelope. Photometric analyses were carried out the measure the optical properties of a sustainable light coloured cool paint. Dynamic energy simulations were run for different Mediterranean localities (Rome, Palermo, Seville, Athens, Tripoli), buildings geometry (stand alone and row house), different thermo-physical properties of the opaque envelope (solar reflectance, U-value, thermal capacity) and of the whole building (natural ventilation rates and shading of glazing systems). The influence of reflective materials was assessed respect to the cooling and overall energy demand. The same simulations were repeated considering not cooled dwellings and the related thermal comfort conditions