Based on the nominal lithium production rate in the produced geothermal brines in Bruchsal a first set of lithium extraction chambers has been designed for the planned lithium extraction bypass. The first design includes geometrical fluid flow parameters and is based on the results of the first successful performed laboratory tests. Since the produced fluid in Bruchsal is a 2-phase mixture, CO2 is both dissolved and gaseous. Therefore, the pressure in the lithium extraction chambers needs to be controlled and potentially released CO2 needs to be led back to the reinjected brine. Additional laboratory tests are planned to optimize the lithium recovery within the extraction chambers and to modify and adapt the design of the prototype.