Enhancement of a solar still performance by inclusion the basalt stones as a porous sensible absorber: Experimental study and thermo-economic analysis

In the present study, a thermo-economic investigation was implemented to assess the enhancement of a solar distillation system (solar still) performance and productivity by inclusion a natural fine stone (black basalt) as a porous sensible absorber. The effect of stone size (1 cm, 1.5 cm and 2 cm) and porosity of the porous absorber on system performance and productivity was presented. Two models with the same design and specifications (conventional and enhanced) were tested and compared. The results illustrated that the yield of solar still for 1 cm, 1.5 cm and 2 cm stone size was about 0.901, 1.005 and 1.075 L/m2 with enhancement about 19.81, 27.86 and 33.37%, respectively compared to conventional solar still. Also, the highest daily thermal efficiency of a solar still was about 22.6% at 2 cm stone size with enhancement about 32.07%. The economic analysis revealed that the freshwater produced cost per liter by solar still utilizing 2 cm stone size was 0.017 $/m2.liter, whereas that for the conventional still is 0.020 $/m2.liter with reduction about 17.53%. So, the stone size of the heat storage absorber has a significant effect on solar still productivity and performance. •The effect of the sensible porous absorber on SS yield and performance was investigated.•The daily SS water yield was about 1.075 L/m2 with improvement about 33.37%.•The daily thermal efficiency was enhanced by about 32.07%.•The cost of produced water was reduced by about 17.53%.