Performance of a single slope solar still using different porous absorbing materials: an experimental approach.

Desalination is a critical process to address water scarcity in arid regions worldwide, and solar stills provide an economical solution despite their productivity limitations. This study aimed to enhance the performance and productivity of solar stills by constructing two stills with different natural and artificial absorbing materials such as black luffa, luffa, fine steel wool, and steel wool pads. The solar stills were tested in Egypt under comparable weather conditions, and their productivity, solar intensity, wind velocity, and temperature were measured to determine their thermal efficiency and exergo-economic analysis. Results showed that the choice of absorbing material significantly impacted solar still productivity, with steel wool pads achieving the highest yield of 4.384 l/m2. Moreover, steel wool pads also exhibited the highest thermal efficiency at 32.74%. The cost per liter (CPL) was the lowest with steel wool pads at 0.0034 $/l/m2. Finally, the payback period and exergo-economic analysis demonstrated that incorporating steel wool pads was the most promising modification for enhancing solar still performance compared to other modifications.

Exergoeconomic and enviroeconomic evaluations of conventional solar still using PCM and electric heater powered by solar energy: an experimental study.

Solar stills are used in distant and arid areas to convert brackish or salty water into potable water fit for human use in a simple, affordable, and effective manner. Even when PCM materials are used, typical solar systems still have minimal production per day. In this study, experimental tests were carried out in order to increase the performance of a single-slope solar still combined with PCM material (paraffin wax) and a solar-powered electric heater. Two identical single-slope solar stills were designed, fabricated, and tested under the same climatic conditions during the summer and spring seasons of 2021 in Al-Arish, Egypt. The first is a conventional solar still (CVSS), and the other is also a conventional still but with PCM and an electric heater (CVSSWPCM). Several parameters were measured during the experiments, including sun intensity, meteorological aspects, cumulative freshwater production, average glass, and water temperatures and PCM temperature. The improved solar still was evaluated at different operating temperatures and was compared to the conventional traditional one. There were four cases studied: one case without a heater (paraffin wax only) and three other cases with a heater operating at 58 °C, 60 °C, and 65 °C, respectively. The experimental results revealed that activating the heater inside the paraffin wax increased daily production (i) in the spring by 2.38, 2.66, and 3.1 times and (ii) and in the summer by 2.2, 2.39, and 2.67 times at the three above-mentioned temperatures respectively (when compared to the traditional still). In addition, the maximum rate of daily freshwater production was achieved at paraffin wax temperature of 65 °C in both spring and summer (Case 5). Finally, the economic evaluation of the modified solar still was carried out according to cost per litre. The modified solar still with a heater operating at 65 °C has a higher exergoeconomic value than the traditional one. The maximum CO2 mitigation in cases 1 and 5 was approximately 28 tons and 160 tons, respectively.