Improving solar still efficiency using optimized fin geometry and cost-effective selective coatings

This experimental study investigated the combined impact of integrating novel fin geometries on the absorber plate with appropriate paint coatings to enhance the absorber plate temperature. Three geometries of fins, namely hemispherical, trapezoidal, and trapezoidal fins with fillet projections, wer...

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Bibliographic Details
Main Authors: Vijay Kishorbhai Mehta, Hitesh Panchal, Md Irfanul Haque Siddiqui, Dan Dobrotă
Format: Article
Language:English
Published: Elsevier 2025-07-01
Series:Desalination and Water Treatment
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Online Access:http://www.sciencedirect.com/science/article/pii/S1944398625003704
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Summary:This experimental study investigated the combined impact of integrating novel fin geometries on the absorber plate with appropriate paint coatings to enhance the absorber plate temperature. Three geometries of fins, namely hemispherical, trapezoidal, and trapezoidal fins with fillet projections, were designed and machined on aluminum absorber plates measuring 10.5 cm × 10.5 cm using a Vertical Machining Center (VMC) machine for research work in the climate conditions of Rajkot, Gujarat, India. Four commonly available black coatings, including spray paint, oil paint, blackboard paint, and nail polish paint, were tested on the absorber plate in this study. An experimental setup under a closed glass cover system was employed to evaluate the thermal performance without water in the basin, isolating the effect of various fin geometries and surface coatings. The results indicated that the absorber plate coated with oil paint delivered the highest temperature (65.07 °C) attained in the closed system, owing to its superior heat retention properties. Among the fin geometries, hemispherical fins showed the best performance, achieving the highest average plate temperature (68.10 °C) and best shape factor (0.9), indicating superior thermal retention with reduced radiative losses. The results suggest that using oil paint and a novel hemispherical fins geometry is a cost-effective and efficient solution for enhancing the thermal performance of solar stills, particularly in low-cost rural applications.
ISSN:1944-3986