Potable water production using two solar stills having different cover materials and fabrication costs

Abstract

Solar stills are very cost-effective technologies used in producing potable water. This work aims to investigate the productivity of two passive double sloped solar stills fabricated with different cover materials with similar shapes; polythene film (PSS) and glass (GSS). The first solar still was made of a transparent polythene film, PVC pipes and a black painted stainless steel trough as cover, frame and basin, respectively. The second one was fabricated using glass as cover, with similar basin material. Experimental outputs indicated that GSS had 1%-5% higher yield than PSS throughout the experiment. The fabrication cost of PSS was 5 times less than the cost of the GSS. The thermal energy efficiencies of PSS and GSS were obtained as 34.05% and 35.50%, respectively. A mathematical model for each solar still was developed using the relationships of heat and mass transfer and their calculated and experimental productivities were in good agreement. Water quality parameters tested showed that water produced from both solar stills met the WHO standards for drinking purposes.

Investigation on Productivity Enhancement of a Solar Still With Transparent Polythene Film Cover and Cylindrical Hollow Fins for Heat Storage

“…The conventional water treatment plants are expensive to build, centralized and are usually far away from these remote areas. Thus, a lowcost treatment technology such as solar desalination (using solar distillation stills) is deemed appropriate for obtaining potable water [Ahsan et al, 2014;Jasrotia et al, 2012;Riahi et al, 2015;Riahi et al, 2018;Velmurugan et al, 2008]. The solar stills that are exposed to the Sun directly, are known as passive solar stills [Dwivedi and Tiwari, 2010].…”

“…The solar stills that are exposed to the Sun directly, are known as passive solar stills [Dwivedi and Tiwari, 2010]. These solar stills can treat seawater, groundwater, lake water, pond water and industrial effluents [Ahsan et al, 2014;Jasrotia et al, 2012;Riahi et al, 2015;Riahi et al, 2018;Velmurugan et al, 2008] in order to provide safe potable water that meets the WHO drinking water standards.…”

“…A concave shaped wick was applied as a basin heat absorber in a pyramid shaped glass cover solar still in Egypt [Kabeel, 2009]. The solar still achieved a yield of 4.10 l/m 2 The investigations on passive solar stills with low-cost transparent cover materials and different heat absorbing materials in the basin were conducted in India [Phadatare and Verma, 2007] and Malaysia [Ahsan et al, 2014;Riahi et al, 2015 andRiahi et al, 2018]. A trapezoidal solar still using a Perspex sheet as cover, frame and basin material was constructed and tested using different basin water depths from 2 cm to 10 cm in India [Phadatare and Verma, 2007].…”

“…A comparative experimental work was conducted with two passive dual slope solar stills using glass (GSS) and polythene film (PSS) as cover materials in Malaysia [Riahi et al, 2018]. A water depth of 3 cm was applied in each still basin.…”

“…However, the PSS fabrication cost was 5 times lower than the cost of GSS. Therefore, PSS was proposed to be applied in the rural regions for cost-effective drinking water production [Riahi et al, 2018].…”