Performance evaluation of a HDH desalination system using direct contact packed towers: experimental and mathematical modeling study

Humidification–dehumidification desalination (HDH) is one of the suitable methods for desalination of saline and brackish water in a small scale. In this research, a HDH desalination method with a direct contact dehumidifier has been analyzed theoretically and experimentally. The setup consists of two similar packing towers for humidification and dehumidification, 10 inches in diameter, which are filled up to 1 m with Rushing packing. In this new HDH configuration, seawater and freshwater recirculation has been used in humidifier and dehumidifier sections, respectively. A steady-state mathematical model based on the mass and energy equations for each system component is presented. The effect of various input parameters on the freshwater production, gain output ratio (GOR) and specific energy consumption has been investigated. The results revealed that the inlet seawater and air temperature to the humidification tower had the highest and the lowest effect on the produced freshwater, respectively. Also, the maximum value of the GOR is 3.3, which is obtained in the equilibrium condition of the dehumidifier. The experiments show that the freshwater production of the proposed HDH device is 300 L/day, which can provide water for domestic consumption of a small family.