A test rig to study heat transfer of sCO2 at CERN Pedano Medina Camila Rocio KIT - Karlsruhe Institute of Technology (DE) Gleissle Susanne Offenburg University of Applied Sciences (DE) Petagna Paolo CERN 2025 In high-energy physics (HEP) detectors and modern electronics, thermal management is critical to ensure reliable, long-term operation. Increasing power densities, compact geometries, and stricter environmental regulations are driving the need for efficient, low-GWP cooling solutions. At CERN, boiling carbon dioxide is already well-established for low-temperature detector cooling. However, above its critical temperature (31°C), sCO2 becomes a highly attractive option for electronics operating in the warm regime. This poster presents the newly built test rig to characterize heat transfer with sCO2. CONFERENCEPAPER