An innovative multi-stage flash distillation unit integrated with evacuate tubes water heater and water mists: A (4E/2S) estimation

Multi-stage flash distillation represents an outstanding technology in purifying saline water. This work experimentally tested a novel three-stage flash distillation unit that utilizes heat from an evacuated tube water collector and electricity from a photovoltage panel. The study examined three flow rates of feed water (8,16, and 24 L/h) and five solar collector temperatures (75, 80, 85, 90, and 95 °C) without and with water mists. These cases are examined and compared regarding system freshwater outputs, salinity, performance ratio, recovery ratio, and 4E/2S analysis (energy, exergy, economic, environmental, sustainability, and sensitivity). The optimal performance occurred when the flow rate was 24 L/h, and the solar collector temperature was 95 °C. Under this flow rate and temperature, the average daily yield was 48.59 L, with a water price of 6.49 dollars per cubic meter. The energy efficiency reached 78 %, and the exergy efficiency was 6.18 %, all at an exergoeconomic factor of 5.93 kWh/$. Moreover, the amount of CO₂ reduced was 243.47 tons, based on energy output, and 14.52 tons, based on exergy output. Sustainability analysis showed promising payback periods, with an energy-based payback time of only 0.44 years and an exergy-based payback time of 7.36 years, all at a sustainability index above 1. The sensitivity analysis showed that low interest rates and longer lifetimes increased exergoeconomic factors and reduced total annual costs. Finally, incorporating water mists enhanced the productivity of drinkable water and multi-stage flash performance ratio by 47.2 % and 43.47 %, respectively, with enhanced energy, exergy, economics, environmental, and sustainability outcomes.