keywords: Solar still; tilt angle; solar radiation; bottom loss coefficient; insulation thickness; distilled water
This research is focused on construction and performance evaluation of a 10 Litre optimized solar still. Modelled using Engineering Equation Solver (EES), parameters such as the tilt angle, water depth and insulation thickness were optimized using MATLAB. The optimized solar still was constructed using insulator thickness of 50 mm and a collector tilt angle of 11.6 0 obtained from the thickness that provides the minimum heat losses and collector tilt angle that give optimum insolation. The performance of the solar still was validated by simulating and comparing with the experimental data obtained. Quality analysis of the water before and after treatment was carried out. Experimental results show that the daily distillate produced was about 10.0 litres/day/m 2 , with efficiency of 64.99%. Results obtained for the untreated water are as follows: Total dissolved solids (TDS) 4.4 mg/lit; dissolved oxygen (DO) 17.5 mg/lit; biochemical oxygen demand (BOD) 15.5 mg/lit and Electrolytic conductivity (EC) 177.3 mg/lit. For the treated water, the TDS, DO, BOD and EC were reduced to 0.01, 5.5, 2.5 and 25.0 respectively, showing that the solar still is capable of improving the quality of undistilled water of very high TDS, DO, BOD and EC values to a level safe for drinking and other industrial purposes. Statistical analysis of the water and glazing temperatures gave RMSE values of 3.41 0 C and 3.5 0 C ,and NSE values of 0.9072 and 0.8306 between the model and the experimental results, implying good quality of fit between the experimental and the simulated data.