Experimental and numerical study of supercritical CO2 cooler

Heat exchangers are major components that significantly influence the performance and size of industrial processes. Supercritical CO 2 (sCO 2 ) is a highly promising working fluid for various applications due to its potential to reduce equipment size, lower environmental impact, and enhance performance. The properties of CO 2 near the critical point exhibit significant variations, making it particularly favorable for heat transfer. As part of the Horizon 2020 DESOLINATION (DEmonstration of concentrated SOLar power coupled wIth advaNced desAlinaTion system in the gulf regION) project, a printed circuit heat exchanger (PCHE) for an sCO 2 power cycle was designed, additive manufactured, and tested. Computational fluid dynamics (CFD) simulations using the SST k - ω turbulence model and real-gas equation of state were used to analyze the heat transfer performance and friction losses of the PCHE in detail. By combining experimental measurements with numerical simulations, this study provides a comprehensive evaluation of the thermo-hydraulic performance of sCO 2 near the pseudo-critical region under various operating conditions (73.78 < p < 92.32 bar, 307.02 < T b < 334.74 K, 1823 < G < 4064 kg/m 2 s). A new friction factor correlation, derived from experimental data, is proposed to enhance the accuracy of friction loss predictions for sCO 2 flows in microchannels, with errors within ± 10 %. These results support the development of more reliable pressure loss models for sCO 2 in compact heat exchangers and contribute to improved predictive capabilities for next-generation energy systems operating under supercritical conditions. • Experimental study of sCO 2 cooling in a printed circuit heat exchanger. • Real-gas CFD simulations validated with experimental data. • Surface roughness effects modelled and validated for additively manufactured PCHE. • New empirical correlation proposed for sCO 2 friction factor with rough walls.