Graph-based modelling and simulation of liquid immersion cooling systems. (15th September 2020) - Lionello, Michele
Abstract: Currently, most of the existing data centers use chilled air to remove the heat produced by the servers. However, liquids have generally better heat dissipation capabilities than air, thus liquid cooling systems are expected to become a standard choice in future data centers. Designing and managing these cooling units benefit from having control-oriented models that can accurately describe the thermal status of both the coolant and the heat sources. This manuscript derives a control-oriented model of liquid immersion cooling systems, i.e., systems where servers are immersed in a dielectric fluid having good heat transfer properties. More specifically, we derive a general lumped-parameters gray box dynamical model that mimics energy and mass transfer phenomena that occur between the main components of the system. The proposed model is validated against experimental data gathered during the operation of a proof-of-concept immersion cooling unit, showing good approximation capabilities. Highlights: This paper considers modelling of liquid immersion cooling systems for data centers. A lumped-parameters graph-based modelling approach is used. We take advantage from the knowledge of the physical phenomena and the process data. The considered modelling framework facilitates model-based control design.