Comparison on solar shadings: Monitoring of the thermo-physical behaviour, assessment of the energy saving, thermal comfort, natural lighting and environmental impact

• Thermo-physical behaviour of different typologies of external solar shadings.
• Low differences on summer and winter energy consumptions.
• Great influence on indoor comfort conditions (to avoid overcooling in mid seasons).
• Wooden persiana provides comfort, low environmental impact, light uniformity.
• Aluminium horizontal louvers should be movable and with long slats.

The paper presents an analytical and experimental study on external solar shadings. The purpose is to compare the behaviour of different typologies in various seasons in a Mediterranean climate from the point of view of thermo-physical behaviour, energy consumptions, thermal comfort, day lighting and environmental impact. The study included two phases:i.Simultaneous summer monitoring of different devices typical of a perimeter office building: sliding perforated panels, ventilated double-glazed window, aluminium horizontal louvers;ii.In-depth study of the louver shading devices through the analysis of the impact of adopting different materials, length of slats and vertical distance between slats. Configurations mainly adopted on residential buildings were also considered. The following activities were carried out: simultaneous winter monitoring of different louver shading devices, aluminium horizontal louvers, aluminium persiana, traditional wooden persiana; dynamic thermal simulations (Energy Plus software) to analyse energy consumptions, indoor thermal comfort and daylighting for different seasons and louvers configurations; assessment of the environmental impact with LCA analysis (SimaPro software).The study made it possible to highlight different behaviours of the shadings depending on their specific characteristics. The shade permeability influences the presence and efficacy of the stack effect in the air channel behind it while its geometries and materials (with relative optical and thermal properties) have an impact on the temperature trends of the adjacent layers, on yearly consumptions, on indoor thermal comfort and on uniformity level of the natural light. The results demonstrate that the wooden solution could to be a good compromise between the different aspects and that adopting an aluminium louver screen it is important to choice configurations characterized by wide and movable slats.