Productivity enhancement of hemispherical solar still using Al2O3-water-based nanofluid and cooling the glass cover

The hemispherical distiller characteristics are having a large surface area for receiving and condensing compared to a conventional single-slope distiller. To achieve the maximum possible utilization of this feature, in first the Al2O3 nanoparticles were adding to the basin water to increase the evaporation rate, in the second modification the glass cover cooling technology was utilized to increase the condensation rate. To investigate the influences of Al2O3-water nanofluid and the glass cover cooling technology by a water sprinkler on hemispherical solar distiller performance, three hemispherical solar distillers were designed and tested in the same climate conditions. The first is the reference case (conventional hemispherical solar distiller), second is the modified hemispherical solar distiller with Al2O3-water nanofluid, and the third is the modified hemispherical solar distiller with Al2O3-water nanofluid and water sprinkler. Three different concentrations of Al2O3 nanoparticles 0.1, 0.2, and 0.3% were studied. Results showed that, the accumulative yield of traditional hemispherical solar distiller reached 3280 ml/m2/day, while the utilization of Al2O3-water nanofluid and the water sprinkler improve the accumulative yield to 6750, 6900, and 7250 ml/m2/day, with improvement 105.8, 110.4, and 121% of the volume friction of 0.1, 0.2, and 0.3%, respectively. Also, the improvement in the daily efficiency for utilizing the Al2O3 nanoparticles and water sprinkler reached 105.7, 109.7, and 120.1% for nanoparticle concentrations 0.1, 0.2, and 0.3%, respectively as compared to the reference case.