Comparative study of double-slope solar still, hemispherical solar still, and tubular solar still using Al2O3/water film cooling: a numerical study and CO2 mitigation analysis

Solar still, as one of the important devices for generating water using renewable energy, has been widely used in arid as well as coastal areas where access to fresh water is limited. This paper uses CFD simulation to compare double-slope solar still, hemispherical solar still, and tubular solar still using nanofluid film cooling. Al2O3-water nanofluids with a concentration of 0.1% are used due to facilitate sunlight penetration into the absorber plate inside the solar desalination. It is assumed the flow is steady, laminar, and air is an ideal and incompressible gas. The simple algorithm is considered to calculate the relationship between pressure and velocity and to separate the transfer and pressure interpolation terms from the appropriate upstream designs. Also, the economic, exergoeconomic, and CO2 mitigation parameters of various solar stills were investigated. The study revealed that the water productivity of double-slope solar desalination using nanofluids film cooling is improved by about 4.8% compared with tubular solar desalination with nanofluid film cooling. Also, the lowest CPL of 0.0362 $/L was obtained in the double-slope solar desalination using nanofluid film cooling. The net CO2 mitigation of 14.08 tons, 13.72 tons, and 13.44 tons was obtained for double-slope solar desalination, hemispherical solar desalination, and tubular solar desalination, respectively.

Automated summary

This study compares the performance of different types of solar stills under nanofluid film cooling using CFD simulation. The results show that the double-slope solar still with nanofluid film cooling has higher water productivity, lower cost, and CO2 mitigation.