Search Results (3)

A solar still is an eco-friendly device that makes use of ample solar energy for the purification of water. The main objective of this research is to increase the yield output of a double-slope solar still (DSSS) by coupling the basin liner with copper tubes and parabolic fins. In this work, the experiments were supervised for nine days with three different cases. For these experiments, copper tubes with thickness of 2 mm, outer diameter of 32 mm, inner diameter of 28 mm, and parabolic fins with 30 mm diameter and 50 mm height were considered. In the first case, non-coated copper tubes (NCCTs) were used, in the second case, coated copper tubes (CCTs) were employed, and in the last case, coated copper tubes with a combination of parabolic fins (CCTPFs) were used. The MSS (case-III) demonstrated a substantial yearly productivity enhancement of 57.79%, establishing its superiority in terms of output because of its higher daily distillate yield of 1215 mL/day in contrast to CSS. When compared, case III—CCTPF—performed better than case II—CCT—by 35.75%. The CSS and MSS both contributed to a decrease in the pH of the saline water, which went from 8.18 to 7.64 and 7.23, respectively. In comparison to the MSS and CSS, which had 0.428 mg/L and 0.569 mg/L of fluoride ions, respectively, brine water had a fluoride ion level of 0.734 mg/L. Total dissolved solids (TDS) concentration before desalination was 440 ppm and it was minimized to 20 ppm with MSS and 55 ppm with CSS, respectively, post-desalination. The corresponding cost per liter (CPL) of MSS and CSS is USD 0.053 and USD 0.040, respectively. Full article

Increasing the evaporation zone inside the solar distiller (SD) is a pivotal method for augmenting its freshwater production. Hence, in this work, a newly designed prismatic absorber basin covered by linen wicks was utilized instead of the conventional flat absorber basin to increase the surface area of the vaporization zone in a double-slope solar distiller (DSSD). Meanwhile, for further enhancement of modified DSSD performance, dual parallel spraying nozzles are incorporated underneath the glass cover as a saltwater feed supply to minimize the thickness of the saltwater film on the wick, which enhances the heating process of the wick surface and, consequently, the evaporation and condensation processes are improved. Two double slope distillers, namely a double slope solar distiller with wick prismatic basin and dual parallel spraying nozzles (DSSD-WPB&DPSN) and a traditional double slope solar distiller (TDSSD), are made and tested in the outdoor summer conditions of Tanta, Egypt (31° E and 30.5° N). A comparative energic–exergic-economic analysis of the two proposed solar stills is also conducted, in terms of the cumulative distillation yield, daily energy efficiency, daily exergy efficiency, and cost per liter of distilled yield. The present results show that the cumulative distillation yield of the DSSD-WPB&DPSN was 8.20 kg/m²·day, which is higher than that of the TDSSD by 49.64%. Furthermore, the energy and exergy efficiencies were increased by 48.51% and 118.10%, respectively, relative to TDSSD. Additionally, the life cost assessment reveals that the cost per liter of the distilled yield of the DSSD-WPB&DPSN is decreased by 11.13% compared to the TDSSD. Full article

Most remote islands are characterized by small populations, many of whom live under the poverty line, poor geographical accessibility and lack of electricity. As such, the solar still, which has a low capital cost, easy operation and less need of maintenance, is recommended to be used in remote islands possessing rich solar irradiance. Against this backdrop, the present study aimed to design and fabricate an effective solar still suitable for application in the remote islands with low freshwater sources but easy access to sea water and rich solar irradiance. Integrating a conventional passive double-slope solar still with an evacuated solar water heater, fins and wick material improves the heat transfer rate through the brine in the basin and increases effective evaporative surface area. Experiments were conducted using batch mode operation during the periods September to October 2021 for the passive solar stills and November 2021 for the active solar still. Experimental results reveal that the augmentation of fins, wicks and a solar water heater influences the overall distillate output of the solar still. The combined use of fins, wicks and a solar water heater increases the average daily productivity by 147% and the average daytime hourly productivity by 245% compared to the conventional passive solar still under similar average solar radiation levels. Using the present design, the active solar still under the solar environment of the testing location can provide 4.4 L of potable water per day. However, to achieve the minimum requirement of 7.5 L/day per person set by WHO, the present design should be modified by increasing the absorber area of the active solar still by 63% and adding eight more evacuated tubes to the solar water heater. The estimated cost per liter of potable water generated by the active (modified) solar still showed that bottled water sold in a typical remote county (Penghu) in Taiwan was 117–283% more expensive than the water generated by the still. Full article