Energy-matrices, exergy, economic, environmental, exergoeconomic, enviroeconomic, and heat transfer (6E/HT) analysis of two passive/active solar still water desalination nearly 4000m: Altitude concept

In spite of numerous valuable researches for evaluating the effect of different parameters for analyzing exergy/environmental/economic/energy-matrices/heat transfer of solar stills; the effect of high altitude (highlands) on these parameters and comparing two active/passive systems was not performed. This paper conducted a meticulous analysis of two active and passive solar stills at different altitudes (Tochal: 3964 m and Tehran: 1171 m) during seven consecutive days between 24.07.2018 and 30.07.2018. The geometry of solar stills in both experiments is similar and for active type, the system utilized with thermoelectric (Peltier) modules and powered by a photovoltaic panel. Results revealed that altitude has a direct effect on the exergy of solar stills where the summit-located solar stills (passive and active) have higher exergy efficiency. Furthermore, higher evaporative exergy is obtained by both active solar stills at the Peak of Tochal Mountain and the center of Tehran. Likewise, heat transfer analysis showed that the highest and lowest heat transfer coefficients are obtained by active solar still at the Peak of Tochal Mountain and passive solar still in Tehran respectively. However, due to the higher glass temperature, the highest radiative heat transfer coefficients are obtained by Tehran-located systems. Economic results showed that the highest and lowest cost of water with 0.0079 and 0.0372 $/L are assessed by passive solar still in Tehran and active solar still at the Peak of Tochal Mountain respectively. Energy-matrices indicated that the lowest and highest energy payback time based on energy and exergy with 1.57 and 52.75 years attained by passive solar still in Tehran. Also, Environmental analysis showed that higher CO₂ mitigation obtained by active solar stills rather than passive types in both locations. Also, enviroeconomic as well as exergoeconomic (based on energy) parameters showed that both passive and active SSs at the city of Tehran have higher values rather than that of solar stills at the summit because of higher days of operation during the year.