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 16th century villas in Costozza (Vicenza, Italy) is analysed and modelled 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, which is analysed here in more detail. The outcomes permit us to better understand 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 for how geothermal renewable resources can be used to improve indoor comfort and limit energy consumption in modern buildings in a temperate climate. A macroscopic analysis of the global airflow system as well as a detailed analysis of Villa Aeolia are developed. All results are validated with analytical methods, numerical methods, and with past experimental records. The system can provide fresh airflow rates that cool the walls of the room and maintain the temperature below 20 ° C even on hot summer days. An advantage is that the system works in a self-adaptive way, the airflow increases when the outdoor temperature increases. This self-adjustment allows us to compare the cooling system to a modern environmental control system.