Performance correlations of an adjacently internally-cooled membrane contactor applied for liquid desiccant air dehumidification

•An adjacently internally-cooled plate membrane liquid desiccant dehumidifier (AIMLDD) is applied.•The AIMLDD is used for liquid desiccant air dehumidification.•A lumped parameter model is established to study the heat and mass transports in the AIMLDD.•An analytical solution of the performances are obtained and experimentally validated.•The performances of the AIMLDD are about 3.3–9.1% larger than those of the cooling tube type. An adjacently internally-cooled plate membrane liquid desiccant dehumidifier (AIMLDD) is like a four-fluid heat and mass exchanger. The feed air and the solution streams flow in the neighboring channels formed by plate membranes. The water falling film and the sweeping air stream flow in the cooling channel formed by two plastic plates. Absorption heat generated in the solution by absorbing the water vapor transferred from the feed air across the membranes can be taken away by the water. A lumped parameter model is established in a unit cell containing half of a feed air channel, a membrane, a solution channel, and half of a cooling channel, to study the heat and mass transports in the AIMLDD. An analytical solution of the normalized governing equations is obtained. Cooling effectiveness, dehumidification effectiveness, dehumidification rate, energy transfer rate of the feed air, and the ratio of the sensible heat transfer rate of the water to the energy transfer rate are calculated and experimentally validated. The performances of the AIMLDD are compared with those of an internally-cooled plate membrane liquid desiccant dehumidifier with cooling tubes inside the solution channels (IMLDD). The performances of the AIMLDD are about 3.3–9.1% larger than those of the IMLDD.