Energy-saving and thermal comfort potential of vernacular urban block porosity shading

Abstract

Built environment configurations of vernacular architecture are the result of an evolutionary adaptation to climatic conditions, while the historic districts of many cities worldwide are shaped by their extensive architectural heritage. These factors, coupled with the present day awareness and renewed interest in the passive retrofitting of buildings, have prompted a review of traditional strategies, most notably direct solar radiation management through courtyard perforations. Although the vernacular courtyard microclimate has been discussed in the literature in recent years, few studies have successfully translated its climatic benefits to the city scale in order to assess its real potential. There is a notable absence of overall urban estimations of the impact on energy-saving and thermal comfort of some of the most effective strategies, such as the use of shading devices. Combining state-of-the-art GIS-based tools and statistical data analysis from field monitoring campaigns this research performs a large-scale evaluation in urban courtyards in the historic centre of a Mediterranean city. Based on the results obtained it can be stated that a widespread use of shading devices can increase the number of hours of comfort, according to PET, by 27% and can reduce global cooling demand by 31%.