Ancient Use of Natural Geothermal Resources : Analysis of Natural Cooling of 16th Century Villas in Costozza (Italy) as a Reference for Modern Buildings

The geothermal cooling system of six villas of the 16th century in Costozza (Vicenza, Italy) is analysed and modeled by using Computational Fluid Dynamics and referring to in-field monitoring data. The system passively cools the villas in summertime by means of underground ducts connected to the caves present in the nearby hills. It still perfectly works in Villa Aeolia, that is here analysed in more detail. The outcomes permit to understand in a better way the functioning conditions and to improve the conservation of the villas as a whole. Furthermore the ancient cooling system can be used as a reference of how geothermal renewable resources can be used to improve the indoor comfort and limit the energy consumption also in modern new buildings in a temperate climate. extbf{On one side a macroscopic analysis of the global airflow system and on the other side a detailed analysis on Villa Aeolia are developed. All results are validated with analytical methods, numerical methods and with the past experimental records. The system can provide fresh airflow rates that cool the walls of the room and maintain the temperature below 20$^circ$C even on hot summer days. The system is adaptive, the airflow increases when the outdoor temperature increases. This self-adjustment allows us to compare the cooling system to a modern environmental control system.