Characterization and assessment of cool coloured solar protection devices for Mediterranean residential buildings application

Cooling down buildings and cities is becoming a priority as a consequence of global increase of air temperatures. This effect determines the growing of energy consumption for cooling, as well as the spread of urban heat island effect. Cool materials are characterised by high solar reflectance and high infrared emissivity. These two properties allow the material to stay cool under the solar radiation. Cool materials are deserving attention to mitigate surface temperatures in buildings and urban materials. This paper presents the first results of the potential benefits of cool materials applied on solar protection devices. Shutters are used for security and for solar shading in Mediterranean countries. These components are generally characterised by high solar absorbance, due to the colours traditionally used. An experimental campaign was carried out to measure and compare the optical and thermal properties of conventional and cool coloured materials. The results were used as input to assess the impact of these products in Italian dwelling, taking into account several variables: climatic zone, insulation level, and operative conditions. The cooling energy demand and the thermal comfort conditions were calculated with an hourly heat balance building simulation tool.

► Spectral and angular reflectances were measured.
► Solar reflectance increased up to 4 times for cool coloured samples.
► Near infrared reflectance increased up to 10 times for cool coloured samples.
► Energy savings up to 10% were calculated.