Passive cooling strategies for overheating reduction and indoor comfort optimization in architectural heritage

Given the significant number of buildings on both national and European territories, the enhancement of environmental quality and indoor comfort and the reduction of the energy footprint of existing buildings, in particular historical ones, have gained increasing importance. Meanwhile, the need to align existing architectural heritage with several international and national policies on climate change adaptation and cultural heritage preservation has emerged. According to the most recent climate change projections, dense and established urban environments, in particular historic centres in the Mediterranean region, will be affected by considerable increases in extreme temperatures and heat waves. As a result, it is crucial to adapt existing architectural heritage, including the historical and cultural one, to achieve optimal indoor comfort and energy efficiency standards, in compliance with relevant constraints. In this regard, the study investigates the level of indoor comfort in historical-cultural buildings located in the historical centre of Rome which are characterised by excessive indoor overheating during summer, resulting in users’ discomfort and increased energy and economic consumption related to air conditioning. The study is carried out through bioclimatic analysis and dynamic simulations of the indoor environment. The objective is to identify passive and evaporative cooling strategies for indoor environments, specifically through the optimization of natural ventilation levels, in order to propose different design scenarios evaluated through a multi-criteria decision analysis based on thermal performance, low environmental impact, and low energy costs. The research highlights how a careful assessment of the users’ needs and of the characteristics of the historical building, as well as synergistic and interdisciplinary collaboration among restoration, architecture, and engineering experts, significantly contributes to the identification of optimal and integrated design solutions.