The transition toward sustainable energy systems requires efficient conversion, storage, and management of heat and energy across a wide range of industrial and technological applications. This project supports these efforts through high-fidelity numerical simulations of flow, heat transfer, and electrochemical processes in systems critical to decarbonization, including additively manufactured cooling structures, electrolyzers and fuel cells, compact heat exchangers, matrix cooling for gas turbines, electronic component cooling, and emerging acoustic and viscoelastic cooling concepts. The work is carried out within the COOLPRO, COOLHEAT, HYDROFUEL, SPARC, and DANE projects and its associated AdTherM competence center, in collaboration with industrial partners such as Alfa Laval, Siemens Energy AB, SSAB, Ericsson, and Infrasonic AB. The overarching objective is to develop a predictive, physics-based understanding of multiscale heat transfer, conjugate coupling, and multiphase electrochemical phenomena, enabling the design of next-generation cooling systems and energy devices with improved efficiency and reduced environmental impact. The simulations employ OpenFOAM, NEK5000, RheoTool, and in-house pseudo-spectral and Lattice Boltzmann solvers for LES, DNS, and coupled electrochemical modelling. In this Medium Compute project, we will perform a targeted set of computational campaigns sized appropriately for NAISS Tier-1 resources (Dardel and Tetralith), making efficient use of moderate-scale parallel jobs to address key aspects of the ongoing research programme. By advancing computational modelling of complex thermal and electrochemical systems within a well-focused and efficient resource envelope, the project will deliver new insights into heat-transfer physics, turbulence, and multiphysics coupling, thereby supporting Sweden’s industrial competitiveness and its transition to a fossil-free, energy-efficient future.