Solar still distillation enhancement through water surface perturbation

• Published in: Solar energy 2020-01, Vol.196, p.312-318
• Main Authors: Porta-Gándara, M.A., Fernández-Zayas, J.L., Chargoy-del-Valle, N.
• Format: Article
• Language: English
• Subjects: Air bubbles; Basin single-slope solar still; Computer simulation; Distillation; Distilled water; Evaporation; Evaporative surface improvement; Experimental solar stills; Flow rates; Improve distillation efficiency; Mass transfer; Perturbation; Solar energy; Solar stills
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2019.12.028

•Perturbation of water surface is explored to improve single-slope solar still production.•Air bubbles injection produces surface ripples increasing evaporative area.•The overall evaporative mass transfer coefficient is enhanced.•Experimental results show a yield increase of 12% in perturbed solar still.•Experimental results are processed in a mathematical model. Solar still water production enhancement was measured in experimental single-slope basin-type solar stills (BTSS) by perturbing the water surface of the still. The perturbation is achieved by the injection of air bubbles into the water basin, which produces surface ripples, thus increasing the overall evaporative surface area and stimulating the mass transfer coefficient. Overall, distilled water production is therefore enhanced as the evaporation improves. The position and flowrate of the air bubble injectors do not seem to affect the amount of evaporation increase. Two very low-tilt covered, shallow BTSS were operated simultaneously side by side. Only one of them was subjected to mass transfer enhancement, in order to produce conclusive mass transfer enhancement results. These results can be accommodated in a computer simulation program with the introduction of a simple intensification factor. Experimental work was carried out in the semi-desert, water-starved, highly insolated region of La Paz, BCS, Mexico.