Effect of porous layer on the efficiency of a single slope solar still-Experimental investigation

In this research, the effect of porous layer on the efficiency of a single slope solar still is studied, experimentally. Accordingly, two single slope solar stills with same sizes containing conventional and modified by using porous layer are fabricated and tested, simultaneously. Black sponge rubber with low heat capacity and wick characteristic is selected as porous material. All experiments were performed in Semnan with geographical coordinates of 35° 33' N, 53° 23' E, Iran. Results showed that daily total water productions enhance by using sponge in solar still. Daily total water productions are 3263 and 3829 cc/m2 for conventional and modified stills, respectively. Accordingly, modified still produces 17.35% more distilled water in comparison with conventional one during one day. There is a direct relationship between trends of daily efficiencies of stills and trends of surrounding temperature or solar radiation intensity.