CFD study of rib-enhanced printed circuit heat exchangers for precoolers in solar power plants' supercritical CO₂ cycle

The modification of printed circuit heat exchangers through extended surface areas is a relatively underexplored topic, especially when considering their application in conjunction with precoolers in supercritical CO₂ cycles. This study evaluates the response of a precooler by incorporating various configurations of integral and interrupted ribs, with the primary objective of identifying an optimized ribs combination under different operating conditions. The results demonstrate that ribs enhance secondary swirl flows, contributing to an increase in heat transfer levels in the supercritical CO₂ flow. However, ribs do increase flow resistance, necessitating the careful selection of the optimal rib combination. The use of non-uniform patterns of interrupted ribs has been identified as the most feasible approach. By reducing the rib length and the distance between ribs at the upstream of supercritical CO₂ and water flows, the performance of the precooler is notably enhanced. No matter the operating condition, cases with shorter rib lengths or smaller rib-to-rib distances at the beginning of both fluid paths consistently yield the best performance. Implementing these configurations in the precooler, the comprehensive performance index can reach approximately 1.2. This study contributes to enhancing efficiency and improving the compactness of large-scale solar power plants utilizing the supercritical CO₂ cycle.