Federico Rossi, an undergraduate student in Environmental Engineering, performed a nice study developing in 2014 some models for a system for potabilization of water using solar energy. The system works with a self-adjusting natural circulation layout, and is able to provide safe, drinkable water at low cost (20-40 lt/h with about 4 m2 of collector surface). The models (Engineering Equation Solver) include design and off-design (EES+TRNSYS).
This work was supervised by G. Manfrida. The presentation (in Italian) is attached.