Data centres serve as critical infrastructures in modern society, supporting a wide range of digital services and technological advancements. However, their high energy consumption, particularly for cooling, poses significant sustainability challenges. This thesis investigates the energy behaviour of data centres, with a specific focus on total and cooling energy consumption in relation to external temperature variations. To provide a comprehensive context, the study begins with an overview of the global socio-environmental landscape, highlighting the increasing importance of sustainability in contemporary energy-intensive industries. A theoretical foundation on cooling systems is then presented, introducing fundamental thermodynamic principles and their real-world applications. Additionally, the role of telecommunications and IT infrastructures (TLC) within the broader energy scenario is explored, with particular emphasis on climatization strategies.