Textile solar shading systems for reducing the negative impacts of solar radiation in urban areas: a critical review

Climate change is bringing attention to low-impact mitigation solutions such as textile solar shading systems that could be more widely used or at least taken into consideration when taking actions to improve the urban environment. In fact, these systems have great potential, especially in historic centres and in areas with high population density. The main aim of this study is to provide a clear and complete picture on the use of textile solar shading in urban areas, critically analysing the most interesting literature with special attention to the impact on the liveability and usability of the urban environment and on the possible energy saving associated with air conditioning, in different climatic locations. From the collection of the research activities, the main considerations for a better design of this type of solar shading systems were summarized. Furthermore, in support of critical analysis of literature, quantitative indicators relating to the impact of textile solar shading systems on the reduction of the summer heat load on buildings, on the reduction of pedestrian thermal stress and on the reduction of pedestrian exposure to UV radiation were proposed and calculated in the three Mediterranean locations (Rome, Athens, Tripoli). From the simplified evaluations proposed, considering a perfectly horizontal and continuous sun sail, with a transmission coefficient equal to 0.1, compared to the case of absence of solar shading systems, an average reduction in the incoming heat flow between 50 % and 60 %; an average reduction in the thermal stress index between 10 % and 40 %; and a reduction in the Standard Erythemal Dose (SED) of nearly 90 % were obtained, for the aforementioned locations.