Currently, the storage ring vacuum chambers of ALBA are protected by 156 crotch absorbers made of copper and Glidcop. After more than 10 years of operation as a third-generation light source, the ALBA II project arose, aiming to transform this infrastructure into a fourth-generation synchrotron. This introduces new challenges in terms of the thermal and mechanical design of the future absorbers. The absorbers’ cooling channels consist of a set of 8-mm-diameter holes parallel to each other and drilled in the body of the absorbers. In each hole, there is a 6x1 mm stainless steel concentric inner tube coiled in spiral wires, whose aim is to enhance the heat transfer. The convective heat transfer coefficients used for the original design of the absorbers come from experimental correlations from the literature, and are applied as a global value for the whole system. In this work, Heat Transfer-Computational Fluid Dynamics (HT-CFD) studies of the convective heat transfer coefficients and pressure gradients in three different cooling channel geometries are carried out, aiming at leading the way of designing the cooling systems toward the CFD simulations rather than applying global experimental values. This information will be useful for the sizing of the new absorbers for the ALBA II project.