“Form follows climate”: l’ottimizzazione della forma architettonica per lo sfruttamento della ventilazione naturale nell’esperienza di Charles Correa.

The growing cooling energy demand, due to the increase in global average temperature and the frequency of heat wave phenomena, is currently leading to a significant increase in electricity consumption and peak electricity demand, increasing the environmental impact of buildings and contributing significantly to global warming, especially in developing countries. On the way to the correct energy design of buildings to face the future increase in cooling energy demand, the implementation of natural cooling techniques such as natural ventilation in buildings can help to ensure indoor comfort conditions by reducing the energy consumption of mechanical cooling systems, even in low energy buildings such as NZEBs. However, the complexity inherent in the three-dimensional and random nature of natural ventilation makes it very challenging to study, analyze and determine the potential of this phenomenon. The effectiveness of natural ventilation, thus its ability to ensure the indoor air quality and passive cooling of a building, depends largely on the design process of the building itself. The analysis of systems used in traditional and vernacular architecture can provide interesting solutions to be used in contemporary design. An important point of view on this subject was offered by the Indian architect Charles Correa (1930-2015), whose architecture, characterized by a strong tendency to exploit natural resources and by an indissoluble link with the climate, is an ante litteram example of the current principles inspiring sustainable design. This research, through CFD simulations coupled with thermal analysis of Charles Correa’s most well-known projects, demonstrates how proper building form design can improve the ventilative cooling efficiency of buildings, ensuring affordable indoor thermal conditions even in adverse climatic conditions like the Indian one. Key factors such as proper orientation to prevailing winds, sizing and positioning of openings, optimization of internal sections, double-height inner core and interconnection between spaces are found to be crucial in improving the effectiveness of wind-driven cross-ventilation in buildings. The following PhD thesis is divided into six chapters as described below. Chapter I presents the background and state of the art on natural ventilation and the potential of ventilative cooling in buildings. Chapter II provides an overview of the physical laws underlying natural ventilation in buildings, focusing on the flow types found in confined spaces and calculation methods, including CFD analysis. Chapter III provides a brief historical excursus on the relationship between building form and climate, focusing on the most significant ways of exploiting natural ventilation in the history of architecture, and offers an introduction on architect Charles Correa. Chapter IV summarizes the compositional and computational fluid dynamics analysis of the case studies, delving into the relationships between building form and natural ventilation. Chapter V presents the evaluation of the effects of the natural ventilation on the thermodynamic behavior and on indoor thermal comfort of case studies through a coupled analysis between CFD software (Ansys Fluent®) and software for the dynamic thermo-energetic simulation of buildings (DesignBuilder®). Chapter VI recaps the main results and conclusions of this research.