Eco-Friendly Water Purification Using a Single Slope Solar Still

Abstract

Access to clean and safe drinking water remains a critical global challenge, particularly in remote and arid regions. This study investigates an eco-friendly approach to water purification through the use of a single-slope solar still, a sustainable and low-cost solution powered by renewable solar energy. Enhancements were introduced to improve the still’s efficiency, including the integration of reflective aluminium foils to maximize solar radiation absorption and the use of blackened stainless steel balls to expand the effective evaporation surface area. Experimental results demonstrated that these modifications significantly boosted freshwater output, with the use of 10 mm steel balls achieving a 38.07% increase in productivity compared to a conventional still. The system operates with zero emissions and minimal maintenance, confirming its potential as a green, scalable solution for decentralized water purification in water-scarce environment thermal e?ciencies by various rates

Introduction

Access to clean drinking water is increasingly threatened by population growth, industrialization, and climate change, especially in arid and developing regions. Traditional water treatment systems in such areas are often inadequate or reliant on fossil fuels. As a sustainable alternative, solar distillation offers an eco-friendly, decentralized solution by using solar energy to purify water through evaporation and condensation.

Among various solar purification methods, the single-slope solar still stands out for its simplicity, affordability, and minimal maintenance. It involves a black-painted basin filled with impure water, covered by an inclined transparent glass sheet. Sunlight heats the water, which then evaporates, condenses on the glass, and is collected as distilled water.

However, conventional solar stills face a major drawback: low thermal efficiency and limited water yield (typically under 5 liters/m²/day). To address this, the study introduces eco-friendly performance enhancements, including:

• Reflective aluminum foil to increase solar input.

• Blackened stainless steel balls to expand the evaporation surface area.

These modifications remain passive, low-cost, and emissions-free, making the improved design well-suited for water-scarce communities and emergency relief.

Materials & Fabrication

Materials used were selected for thermal efficiency, durability, and cost-effectiveness:

• Basin Tray: Galvanized iron (GI), painted black to absorb heat.

• Transparent Cover: 5 mm tempered glass, inclined at 35° for efficient condensation.

• Insulation: 30 mm Thermopolis sheet to reduce heat loss.

• Sealant: High-temperature silicone to ensure airtight joints.

• Frame & Support: Waterproof wood and mild steel legs for durability.

The fabrication process used locally available materials to ensure low cost and field applicability. Components were assembled, sealed, and tested for leakage and structural integrity, producing a simple, effective, and eco-friendly water purification device.

Material Characterization

Material choice directly impacts the efficiency and longevity of the system:

• Galvanized Iron: Good thermal conductivity and corrosion resistance.

• Tempered Glass: High solar transmittance and mechanical strength.

• Thermopolis Insulation: Low thermal conductivity to reduce heat loss.

• Silicone Sealant: High durability and resistance to temperature fluctuations.

Each material was chosen to optimize the still’s thermal performance, structural stability, and environmental suitability, ensuring sustainable operation in challenging conditions.

Conclusion

The single slope solar still offers a sustainable and environmentally friendly method for water purification by harnessing solar energy. Its simple construction using locally sourced materials makes it affordable and accessible for remote and rural communities. Experimental observations confirm that the still efficiently produces distilled water with minimal energy input and no harmful emissions. While the current design performs well under average solar conditions, future improvements like enhanced insulation or integration with phase change materials could further boost its productivity. Overall, the solar still is a promising technology to help alleviate freshwater shortages in an eco-conscious manner...

References

[1] S. Kumar, R. Singh, P. Sharma, “Performance analysis of single slope solar still for water purification,” Proceedings of National Conference on Sustainable Energy Technologies, Indian Institute of Technology, Delhi, India, Nov 15-16, 2015. [2] A.Patel,M. Joshi, “Experimental investigation of solar still with phase change material for enhanced freshwater production,” Proceedings of International Conference on Renewable Energy Systems, Gujarat Technological University, Ahmedabad, India, Feb 20-22, 2017. [3] N. R. Verme, S. K. Gupta, “Enhancement of single slope solar still efficiency using wick and black paint,” Proceedings of National Conference on Water and Energy Conservation, University of Rajasthan, Jaipur, India, Mar 10-11, 2016. [4] L. Fernandez, M. Carballo, “Design and testing of eco-friendly solar still for rural water purification,” Proceedings of International Conference on Environmental Sustainability, University of Lisbon, Portugal, Jun 5-7, 2018. [5] R. Patel, D. Bhatt, “Study of solar still productivity with improved insulation materials,” Proceedings of National Conference on Advances in Mechanical Engineering, Sirdar Vallabhbhai National Institute of Technology, Surat, India, Dec 12-13, 2019. [6] M. S. Khan, P. Kumar, “Performance evaluation of single slope solar still integrated with solar collector,” Proceedings of International Conference on Sustainable Energy Solutions, JamieMillieIslamic, New Delhi, India [7] T. Sharma, A. Verme, “Energy and exergy analysis of solar still with blackened basin and insulation,” Proceedings of National Conference on Renewable Energy Applications, National Institute of Technology, Jalandhar, India, Sep 17-18, 2017.. [8] V. R. Singh, S. Chandra, “Experimental study on eco-friendly solar still with improved condensation surface,” Proceedings of International Conference on Water and Environmental Engineering, Banaras Hindu University, Varanasi, India, Nov 30-Dec 2, 2016. [9] K. Joshi, M. Mehta, “Thermal performance of single slope solar still using locally available materials,” Proceedings of National Conference on Advances in Thermal Engineering, Institute of Technology, Ahmedabad, India, Oct 25-26, 2018. [10] P. S. Desai, A. M. Patel, “Design and performance evaluation of single slope solar still for potable water production,” Proceedings of International Conference on Sustainable Technologies and Environment, Indian Institute of Science, Bangalore, India, Dec 7-9, 2019.

Copyright

Copyright © 2025 Dr. S. Saravanan, Dhinesh S., Thangavel G., Santhosh S.. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.