Enhancing Parabolic Trough Collector Performance Through Surface Treatment: A Comparative Experimental Analysis

Parabolic trough collectors (PTCs) are effective solar thermal systems, but their performance can be significantly enhanced through surface treatments. This research investigates the enhancement of thermal performance in parabolic trough collectors (PTCs) by experimentally evaluating the results of surface coating on the absorber tube surface. To achieve this objective, a closed-loop PTC system was fabricated to conduct an experimental comparison between a conventional simple copper tube and a black-painted copper tube. The experimental setup was placed in Islamabad, Pakistan, operated under both laminar and turbulent flow conditions to measure key performance metrics, of temperature difference (ΔT) between the inlet and outlet. The results demonstrate a significant performance advantage for the black-painted tube. In laminar flow, the black-painted tube achieved an average ΔT of 3.54 °C, compared to 2.11 °C for the simple copper tube. Similarly, in turbulent flow, the black-painted tube’s ΔT was 2.1 °C, surpassing the simple copper tube’s 1.57 °C. This superior performance is primarily attributed to the black surface’s high solar absorptivity, which more effectively captures and converts solar radiation into thermal energy. The findings highlight the critical role of surface treatment in optimizing PTC efficiency and provide a practical method for improving solar thermal energy systems.