In this paper, a hybrid model for heat pipe heat exchanger used for heat recovery in regenerator of Liquid Desiccant Dehumidification System (LDDS) is developed. The proposed hybrid model starts from the physical governing equations and lumps the complex geometric parameters and fluids' thermodynamic coefficients as constants since they have very small changes during the process operation. The resulting model has only three unknown parameters which can be determined by Levenberg-Marquardt method. Compared with the existing heat pipe models, the proposed model is very simple, accurate, and does not require iterative computations. A large amount of testing for the heat pipe heat exchanger installed in a pilot LDDS shows that the model is very effective to predict the performance in a wide operating range. The model is expected to find its applications in monitoring, control and optimization of the regenerator heat recovery process of LDDS. (C) 2016 Elsevier Ltd. All rights reserved.