Novel solar still design using transparent waste bottles

Abstract

With increasing pressure on the global climate under the high worm gases emissions of fossil fuel, the necessity of using renewable energy is rapidly increasing. This study proposed a new solar water desalination system using waste transparent bottles for freshwater production. Two concentric transparent bottles were used. The inner bottle was cut longitudinally and horizontally placed with upward cut direction and filled with black cotton wick saturated by saline water. The outer transparent tube was cut radially to insert the inner smaller bottle inside and then reassembled using a transparent tap. The proposed device was exposed to the sunrays that reached the black wick and the energy absorbed and transferred to the saline water. After a short time, the water evaporation appears and started to condensate on the inner surface of the outer transparent bottle and collected at the bottom of the bottle by gravity. The proposed device showed moderate performance with 30.28% thermal efficiency and 2.95 L/m2day freshwater productivity under August climatic conditions of Cairo city in Egypt. The proposed device reduced the freshwater cost per liter by almost 66.2%, reaching a very competitive level of $0.0042/L. The proposed device can cover the essential freshwater needs for one person/year with not only a reduction of 21.3 tons/year of CO2 emissions but also with a reuse of 117 kg/year of plastic waste bottles.