Investigating the effect of natural elements on thermal comfort in the courtyards of historic houses in Isfahan city

Studies show that the temperature has increased in recent decades and we are facing the heat island phenomenon. This phenomenon has a negative effect on thermal comfort of the residents, and in this sense, cities have faced many challenges, including changes in microclimates and using more energy. Therefore, there is an urgent need for thermal adjustment solutions. Considering that vegetation is one of the most common ways to improve thermal comfort in cities, this research aims to investigate how natural elements such as vegetation and water affect thermal comfort in the courtyards of a number of historical houses in Isfahan. For this purpose, a number of historical houses with central courtyard in Isfahan city are modeled and simulated by Envimet 4 software, and the results related to the changes of Predicted Mean Vote index for the first day of July are calculated. The relationship between natural elements and thermal comfort index is investigated by univariate and multiple regression methods. The changes of thermal comfort index over time show that vegetation can always improve thermal comfort in the microclimate of central courtyard. Regression analysis shows that the factor with the greatest effect on improving thermal comfort is tree cover, while grass and water have a little negative effect on thermal conditions in some hours. Trees both reduce Predicted Mean Vote under the canopy and also reduce the average of index in the whole courtyard in summers of hot arid climates.