Analysis of exergy destruction in data centres

IT equipment and systems, housed in data centres, consume a considerable amount of electricity. Most of the electrical energy consumed by the data centre IT equipment is released in the form of heat. From a second law of thermodynamics analysis point of view, the mixing of hot and cold air streams in the room caused by hot air recirculation is an irreversible process, leading to wasted work potential in data centres. In the work presented here, a numerical analysis of flow and temperature distribution of a raised-floor data centre is conducted in order to evaluate the thermal performance of the data centre. Subsequently, from flow patterns and temperature profiles, a detailed exergy analysis of the data centre is performed to get a better understanding of the room airspace irreversibilities. The amount of the exergy as well as the exergy destroyed in the airspace is evaluated in order to cast a light on the nature of the irreversibilities. Finally, new performance metrics based on the second law of thermodynamics are proposed and used to assess the performance of a data centre. A comparison between the performance metrics based on the first and second law of thermodynamics as well as the limitations of the newly derived performance metrics are discussed.