Experimental analysis of energy and exergy efficiency in a novel solar evaporator prototype for brine treatment

Waste brine generated by industry and desalination must be treated to prevent environmental harm. Zero liquid discharge systems are commonly employed for brine treatment, but current processes consume between 20 and 66 kWh/m3. An advanced solar evaporator, consisting of a covered pond equipped with a controlled fan to enhance evaporation, offers a promising solution to brine management challenges. This study presents the design, construction, and experimental evaluation of a small-scale advanced solar evaporator prototype and analyses its performance. Eight experiments were conducted during the spring: four using tap water and four using salty water. In the freshwater experiments, different ventilation rates were tested, achieving evaporation rates up to 2.05 m3/m2·year and electrical consumption as low as 0.9 kWh/m3. In the saline experiments, initial salt concentrations ranged from 5.4 % to 13 %, with evaporation rates reaching 3.03 m3/m2·year and energy consumption of 2.8 kWh/m3. Thermal efficiency across all experiments ranged from 49.4 % to 65.9 %, with a maximum exergy efficiency of 1.71 %. Furthermore, hourly evaporation rates were correlated with environmental variables. These results demonstrate that the advanced solar evaporator is a highly promising, low-cost alternative to current brine treatments, offering a significant reduction in energy consumption.