The internally cooled liquid desiccant dehumidifier is regarded as an efficient heat and mass transfer component for liquid desiccant dehumidification systems. Compared with the typically adopted adiabatic dehumidifier, three fluids are used inside the dehumidifier: air, liquid desiccant, and the internal cooling medium. Herein, a simplified analytical solution for the heat and mass transfer model of an internally cooled dehumidifier is proposed and validated. The enthalpy efficiency and moisture efficiency of the dehumidifier are deduced from the analytical solutions and are adopted to evaluate the dehumidifier performance. The influences of different inlet, operating, and device parameters on the performance of the device are investigated using the analytical solution. We found that the enthalpy and moisture efficiencies are decided primarily by six dimensionless numbers, three indicating the inlet states of the fluids, one indicating the mass flow rate of air to desiccant, and two indicating the heat and mass transfer ability of the device. (C) 2019 Elsevier B.V. All rights reserved.