The regeneration process represents the vital part of the liquid desiccant air conditioning system. In this study, a solar assisted liquid desiccant packed regeneration tower is tested in a hot-humid climate. The regenerator design parameters are classified as controlled parameters, input parameters and output parameters. The regenerator performance is assessed using previous published results. A new regenerator effectiveness definition based on the desiccant properties is deduced and assessed experimentally. An empirical effectiveness correlation and a quick model are presented to predict the outlet desiccant concentration and temperature. Also, the effect of the design variables on the effectiveness is reported. The new effectiveness and the humidity effectiveness are used to optimize the design parameters.Units: SI