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

Abstract

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.

Design Analysis of a Solar-Powered Water Desalination System Using Humidification Dehumidification for Continuous Water Production

“…m da (h a,2 − h a,1 ) = m fw,o h fw,2 − m fw,i h fw,1 (19) where m fw,i and h fw,1 are mass flow rate and specific enthalpy of freshwater at the inlet of dehumidifier; m fw,o and h fw,2 represent the mass flow rate and specific enthalpy of freshwater at the outlet of dehumidifier; m pw refers to water production during the condensation process.…”

“…The research results showed that the maximum value of net power and water production were 42.68 kW and 236.81 kgh −1 , respectively. Considering the recirculation of seawater and freshwater, Zarei et al [19] raised a CACW HDH desalination system with a directcontact humidifier and dehumidifier. The relevant theoretical and experimental analyses were conducted at the various input parameter conditions, and the results showed that the peak value of GOR and water production are 3.3 and 300 Ld −1 at the equilibrium conditions of the dehumidifier.…”