Productivity enhancement of stepped solar still by loading with magnets and suspended micro charcoal powder

ABSTRACT

Solar desalination technology is an eco-friendly and sustainable pathway to generate pure water. In the current investigation, the stepped solar still were loaded with 10 magnet rings and charcoal powder of 75 microns to make the still efficient. Three different types of solar stills namely, conventional stepped solar still (CSSS), magnetic stepped solar still (MSSS), and magnet charcoal stepped solar still (MCSSS) were tested simultaneously at 1 cm, 2 cm, and 3 cm depths of water. The deployment of magnets in MSSS and magnets and charcoal in MCSSS were found to significantly enhance the radiative, convective, and evaporative rates of heat transfer. The highest total heat transfer rate was found in MCSSS which was more than the rates in MSSS and CSSS by 30.94% and 91.70%, respectively. The cumulative yield outputs in MCSSS were 104.54% and 23.28%, respectively, higher than CSSS and MSSS. The exergetic efficiency in MCSSS was higher by 31.84% and 145.82%, respectively, in comparison to the MSSS and CSSS. In addition, an economic evaluation was carried out and the annual distillation cost and overall cost of one liter of water per 0.25 m² were found to be 48.6 and 0.029 USD, respectively. The results emphatically indicate that the proposed solar still is a simple and economical technique to improve the distillate output in an eco-friendly manner.

Graphical abstract

KEYWORDS:

• Charcoal
• economic assessment
• exergy analysis
• heat transfer coefficients
• magnets
• stepped solar still

Highlights

• The magnetic field increased the productivity of stepped solar still.

• Charcoal in the MCSSS was the key reason for a significant rise in evaporative HTC.

• Cumulative yield output for MCSSS was 104.54% and 23.28% higher than CSSS and MSSS, respectively.

• Maximum total heat transfer rate of MCSSS superseded MSSS and CSSS by 30.94% and 91.70%, respectively.

• Maximum exergy destruction took place at the basin liner followed by glass cover and water.

Acknowledgments

The authors are happy to acknowledge the support by DST water technology initiatives (DST/TMD/EWO/WTI/2K19/EWFH/2019/25).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Nomenclature

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Additional information

Funding

This work was supported by the Department of Science and Technology, Ministry of Science and Technology [DST/TMD/EWO/WTI/2K19/EWFH/2019/25].