Improving the performance of pyramid solar still using rotating four cylinders and three electric heaters

Abstract

The world suffers from the potable water shortage problem. Solar still is a simple device used to convert the brackish water into a drinkable water. We proposed a new modification in the design of the pyramid solar still to enlarge the exposure area and decrease the depth of the water film as possible. So, four rotating cylinders were incorporated into the basin of the pyramid distiller. Also, three electric heaters were fixed on the basin water to raise its temperature. The energy required to run the heaters was captured from a PV system. The performance of the modified pyramid solar still with rotating cylinders (MPSSRC) was investigated under different rotating speeds (0.1, 0.2, 0.5, 1.0, 1.5, and 2.0 rpm). The experimental results revealed that the total distillates of the MPSSRC without heaters and reference still were 7300 and 3000 mL/m² a day, respectively with an improvement of 143 %. In addition, the total distillates of the MPSSRC with heaters and reference still were 9100 and 2900 mL/m² a day, respectively. So, the productivity was enhanced by 214 %. The optimum increase in productivity was obtained at the cylinders’ speed of 0.5 rpm. The optimum thermal efficiency of the MPSSRC was obtained when using the electric heaters with the rotating speed of 0.5 rpm, where it was 65 % and 54 % for the MPSSRC with and without heaters, respectively.