Performance Investigation of a Novel Solar Thermal Desalination System with Brine Recirculation Approach: an Experimental Study

Sustainable freshwater supply due to the destructive effects of climate change has been a real challenge in today's world, especially in arid areas. Among the several approaches for tackling this challenge, the solar thermal desalination technique can be a promising solution as the potential of solar thermal energy for distillation in a decentralized approach. However, these systems have low water production performance and environmental issues due to their brine discharge into their surroundings. The current research proposes a solar humidificationdehumidification with a novel brine recirculation system for brine management purposes. For cost effectiveness, a stepped solar still was selected as an auxiliary system for brine concentration. The augmented solar still enhances the system's freshwater productivity and makes the system work as a minimal liquid discharge system. Then, the designed hybrid desalination system was experimentally tested to investigate its performance and brine concentration procedure. The findings recorded a maximum freshwater production of 1308 ml/day for the overall desalination system. The reduction of the inlet flow rate of the brine to the solar still enhanced the overall system's productivity by 347 ml/day. Moreover, the brine recirculation system's results show the brine concentration increase from 8690 to 9480 mu S/cm along the test. The cost of the distillation was determined as 0.16 $/l based on the cost analysis. Finally, it was shown that the utilization of a solar still for a brine recirculation system promisingly makes an efficient, decentralized, and environmentally friendly solar thermal desalination system.