Amirkabir University of Technology AUT Journal of Mechanical Engineering 2588-2937 4 3 2020 09 01 Experimental Study and Economical Analysis of a Cascade Solar still Integrated with an Evacuated Tube and a Conventional Flat Plate Solar Collectors 301 314 3724 10.22060/ajme.2019.16796.5837 EN Mohammad Vafaei Mechanical Engineering Department, Ferdowsi university of Mashhad, Mashhad, Iran Reza Karimi Mechanical Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran Salar Samadi Semnani Mechanical Engineering Department, Ferdowsi University of Mashhad, Mashhad, Iran Ali Arbabi Mechanical Engineering Department, Bozorgmehr University of Qaenat, Qaenat, Iran Mohammad BarzgarNezhad Mechanical Engineering Department, Bozorgmehr University of Qaenat, Qaenat, Iran Seyed Ehsan Shakib Mechanical Engineering Department, Bozorgmehr University of Qaenat, Qaenat, Iran Ghodrat Ghassabi Mechanical Engineering Department, Bozorgmehr University of Qaenat, Qaenat, Iran Mohammad Hossein Shafiei Mayam Chancellor, Bozorgmehr University of Qaenat Journal Article 2019 07 31 Many researchers have experimentally and theoretically studied fresh water productivity in solar stills. In this regard, water preheating can play a noticeable role in enhancing the productivity of solar stills. In the present study, in order to study the effect of water preheating at the inlet of desalination system, a cascade solar still is built and integrated with two different solar collector in separated modes; an evacuated solar collector and a conventional flat plate solar collector. The mentioned solar still includes an external condenser, fin, and internal and external reflectors. It is worth noting that the embedded fins in the water passage are applied to induce hot spots and increase the evaporation rate and fresh water. The experiments were performed in August 2015 and summer 2017. The results showed that the combined desalination system with conventional flat plate collector and evacuated tube collector enhace productivity %60 and %13, respectively. In addition, efficiency of solar still in combination with conventional flat plate collector and evacuated tube collector was %81.8 and %59.1, respectively. The price of produced fresh water of solar still with conventional collector obtained 0.035 $/lit and for solar still with evacuated tube collector was 0.045 $/lit. https://ajme.aut.ac.ir/article_3724_4172f3101212a2009c74b547b6ddf935.pdf