Annual performance analysis of adding different nanofluids in stepped solar still

The use of MgO and TiO2 nanofluids at different concentrations was investigated annually to evaluate the distillate output of stepped solar stills. Nanofluids concentrations ranged from 0.1 to 0.2% in the present research work. Results confirm that the stepped solar still distillate output is increased by 45.8%, 33.33%, 20.4% and 4.1% with use of MgO nanofluids (0.2% and 0.1% concentrations) and TiO2 nanofluids (0.2% and 0.1% concentrations). The reason for higher distillate output of MgO nanofluid over TiO2 in stepped solar still is lower specific heat capacity and higher thermal conductivity. Finally, the energy payback time was also calculated, and it was still only 3 months for stepped solar stills with the use of 0.2% nanofluid concentration.