Effects of porous medium utilization on condensation heat transfer in dehumidifier of a humidification–dehumidification desalination system: a numerical study

Purpose Solar humidification–dehumidification (HDH) desalination systems that can be used for remote areas are becoming popular among other thermal desalination methods. One of the major challenges the researchers face is the low water productivity of these systems. The purpose of this study is the utilization of the metal matching scraps in the condenser to prepare a porous media-based dehumidifier for increasing its heat and mass transfer and, consequently, the freshwater production rate of the HDH desalination unit. Design/methodology/approach The investigations were performed numerically by simulation of the condenser performance, and different scenarios were tested for four different porosity values, porous material type and the inlet brackish water flow rate to reveal the effect of porosity on the performance of the desalination system. Findings According to the results, an optimum point of 0.975 porosity with 400 mL water production was found to be the best performance of the distillation process. Moreover, selecting copper instead of steel enhanced the distillation by 5.91% and increased the inlet cooling water flow rate to 1.2 L/min, enhancing condensation by 14.25%. Originality/value According to the literature, there were limited numerical studies on the effects of heat transfer improvement by porous medium utilization, especially the effects on the condenser of the desalination unit. Hence, the current research provides a numerical study of the potential of machining metal scraps’ application as a porous medium in the dehumidifier of the HDH desalination systems for freshwater production enhancement.