Experimental Investigation of Photo-Thermal Conversion Characteristics of Natural Extract of Beta Vulgaris-Based Heat Transfer Fluids

The present study describes a novel idea for thermal performance enhancement of a volumetric absorption solar collector system using a natural extract of Beta Vulgaris, commonly known as beetroot in water as heat transfer fluid (HTF) for the very first time. The optical characterization was carried out using a UV–Vis spectrophotometer, which indicated the absorbance peak around 533 nm showing the full use of the visible spectrum. Outdoor experiments showed a maximum temperature gain of 24.91 °C and the maximum photo-thermal efficiency reached nearly 55.6%, which is about 22.8% higher than base fluid, i.e., water. The use of Beta Vulgaris-based heat transfer fluids significantly increased the thermal efficiency of the system compared to water. The study also suggests that such a heat transfer fluid can be a promising alternative for solar thermal applications, leading to a more sustainable and eco-friendly approach to energy generation.