The Effect of Sponge Liner Colors on the Performance of Simple Solar Stills

Abstract

In this experimental study, an attempt has been made to increase the productivity from a simple solar still using different colored sponge liners on the inner wall surfaces. The main objectives of this study are (i) to utilize maximum available energy at the interior part of the still (inner wall surfaces and vapor region) and (ii) to find the effect of sponge liner thickness and color on the performance of the still. Two single-slope, single-basin solar still units are fabricated with an effective area of 0.5 m² and the glass cover is mounted on the still at an inclination of 10° to the horizontal plane. The hourly amount of extracted distilled water, the various temperatures, and the insolation were monitored during January–February 2009. The experiments were conducted on the solar still with various different thicknesses of sponge liners (3, 5, 7, 10, and 12 mm) and different colored sponge liners (white, blue, green, red, and black). Based on the experimental results, it is concluded that (i) a sponge liner in stills increases the temperature difference between water and glass by reducing the temperature of glass, (ii) the 5 mm thickness sponge liner has given 35.2% higher yield than the conventional still, (iii) a solar still with a black sponge liner gives more yield than the others, which is 43.5% higher than the conventional still, and (iv) the sponge-lined stills reduce the conduction of heat losses from the inner wall surface to outer wall surfaces through the back wall and side wall by 50%.

Keywords:

• back wall temperature
• color
• solar still
• sponge liner
• thickness