Heat transfer and cooling uniformity enhancement in PV/T collectors using a thermal absorber with Modified Hilbert-Serpentine flow configuration

The growing demand for low-carbon energy has accelerated the adoption of photovoltaic technologies. Elevated operating temperatures, however, reduce their energy conversion efficiency. Hybrid photovoltaic-thermal systems offer a solution by generating both electrical and thermal energy. Yet, their performance is constrained by limited heat transfer and non-uniform cooling in conventional absorber patterns such as serpentine, spiral, and rectangular spiral. This study experimentally investigates a novel Modified Hilbert-Serpentine Pattern thermal absorber, inspired by the space-filling Hilbert curve, to enhance thermal uniformity and overall photovoltaic-thermal performance. The Modified Hilbert-Serpentine Pattern combines the fractal geometry of the Hilbert curve in the central hotspot region of panel and serpentine channels at the periphery, achieving higher space utilization and superior cooling uniformity. Experimental analysis under typical weather conditions of Guwahati, India, revealed that the collector with Modified Hilbert-Serpentine Pattern attained an average electrical efficiency of approximately 13%, representing a 29.89% improvement over a conventional photovoltaic module (9.90%). The system achieved an average thermal efficiency of 55.90% giving a maximum outlet temperature of 41 °C and an average exergetic efficiency of 15.30%. The proposed design improves electrical and thermal performance through uniform cooling, offering a compact and high-efficiency photovoltaic-thermal solution for broad energy applications.