LAUSR

Abstract The tubular solar still features a huge surface area for receiving and condensing compared to a single-slope single basin still. The present experimental study aims to augmentation of the diurnal and nocturnal distillate of the tubular solar still via additional improvers on design and manufacture. In the current study, closed copper tubes filled with PCM were constructed and fixed in the basin of tubular solar still to improve a distilled production during sunrise, as well as, extend the distilled water production time after the sunset. To investigate the influences of the utilization of the closed copper tubes filled with PCM on tubular still performance, the tubular still with closed copper tubes filled with PCM and traditionalunitwas tested at the same Egyptian climate conditions. The results show that, accumulated production of conventional tubular still varying between 4.1–4.31 L/m2/day, while utilization of the closed copper tubes filled with PCM enhances productivity to 8.82–9.05 L/m2/day with 110–115.1% enhancement in the accumulated productivity during the period June-August 2019.Also, during this period a daily efficiency of conventional tubular still varying between 32.9–33.8%, while utilization of the closed copper tubes filled with PCM enhances daily efficiency to 70.9–72.7% with 114.4–115.5% enhancement in daily efficiency. These results presented that the copper tubes filled with PCM represent good options to obtain the highest performance of tubular solar still.