First results for the characterization of heat transfer with supercritical CO2 in small channels

by Ms Camila Rocio Pedano Medina (University of Applied Sciences (DE))

Thursday 20 Nov 2025, 11:00 → 12:00 Europe/Zurich

32/1-A24 (CERN)

In the field of thermal management, supercritical carbon dioxide (sCO₂) has gained significant attention as a promising coolant for applications ranging from compact heat exchangers to microelectronics cooling. Its favourable thermophysical properties—high density, low viscosity, and a large specific heat capacity near the critical point—allow the handling of high heat fluxes in space-constrained environments. While these advantages make sCO₂ a candidate fluid for future warm detector systems and microelectronics, crucial physical aspects of convective heat transfer in this regime remain poorly understood. In particular, systematic data on heat transfer coefficients and pressure drops in the small-diameter channels relevant for such applications are scarce, and available correlations can often fail to reproduce experimental results consistently.

This talk will introduce a newly developed modular test rig at CERN, designed and built to address these gaps. The facility enables controlled studies of convective heat transfer over a wide range of operating conditions. A key feature is its ability to investigate both subcritical and supercritical operation with the same instrumentation and layout, allowing systematic comparison of evaporative and supercritical cooling within one setup—an aspect that remains largely unexplored. The design and measurement capabilities of the rig will be introduced, and the first results will be presented.