Solar distillation is an effective and practical approach to tackling the global freshwater crisis, especially in water-scarce regions The present study focuses on optimizing the thermo-economic performance of solar still (SS) systems through both experimental investigations and analytical evaluations. Three configurations were examined: (i) a conventional solar still (Case I), (ii) a modified solar still integrated with a vortex tube and ultrasonic fogger (Case II), and (iii) an advanced modification that additionally incorporates a solar air heater (Case III). Experiments were conducted under outdoor conditions at Kermanshah University of Technology, Iran, during June 2024, with precise measurements of temperature, solar radiation, and distilled water yield. The Black Horse Algorithm, combined with comprehensive 6E/HT analyses (Energy, Exergy, Economic, Exergo-economic, Environmental, and Enviro-economic analyses, as well as Sustainability and Heat Transfer), was employed to maximize freshwater production. Results demonstrate that Case III significantly outperforms other configurations, achieving a daily freshwater yield of 1127 mL/m2.day, a 206.66 % improvement over Case I, which yields 367.5 mL/m2.day. Energy and Exergy efficiencies improved by 194.74 % and 282.53 %, respectively, with energy and exergy payback times of 1.69 and 4.14 years. Economically, Case III offers a competitive production cost of 0.245 $/L/m2 over a 10-year lifespan. Through optimization, Case III achieved an enhanced daily yield of 1146.97 mL/m2.day, underscoring its potential as a sustainable, cost-effective, and renewable-energy-driven desalination solution for innovative urban applications.
