Due to many potential problems associated with an open regeneration system in application to reconcentration with liquid desiccants, a closed-type solar regenerator has been simulated and analyzed in this paper. It consists of a flat, blackened, tilted surface with a transparent glazing as a covering. The weak desiccant to be concentrated flows as a thin film over the absorber and the water evaporating from the desiccant due to absorption of solar energy is condensed on the underside of the glass cover. A theoretical model, which includes the variation of rate of evaporation of water along the flow length of the regenerator, has been used to examine the thermal performance of the regenerator. Changes in thermal performance are reported in terms of insolation and the mass of water evaporated from the desiccant for different operating parameters.