Thermohydraulic Experiments on a Supercritical Carbon Dioxide - Air Microtube Heat Exchanger

•Experiments on a shell-and-tube heat exchanger (HX) with thirty-nine microtubes, 5 unit cells and similar design features to future commercial-scale sCO2 systems.•Detailed analysis of thermohydraulic behavior in the HX in high Reynold number ranges that have not been previously studied.•Performance metrics for multiple sCO2 and air flow rates.•Good overall agreement between experimental results and a recent model.