Document Type : SI:Emerging Trends in Photothermal Conversion for Solar Energy Harvesting
Authors
1 Department of Mechanical Engineering, Gujarat Technological University, Ahmedabad, Gujarat. India
2 Department of Mechanical Engineering, BVM Engineering College, Vallabh Vidhyanagar, Gujarat. India
Abstract
Traditional photovoltaic thermal (PVT) systems struggle to simultaneously maximize electrical and thermal efficiencies due to inherent heating issues and incomplete utilization of the solar spectrum. Although nanofluid-based direct absorption methods have been explored, they remain limited by insufficient spectral control and rising cell temperatures. To overcome these challenges, this research investigates the development of a fluid-based spectral beam splitting (SBS) system using water-based titanium dioxide (TiO₂) and zinc oxide (ZnO) nanofluids as low-cost, tuneable optical filters for beam-split PVT (BSPVT) applications. Twelve nanofluid samples with concentrations ranging from 0.01% to 0.05% were prepared and analysed using UV–Vis–NIR spectrophotometry across 200–2500 nm. The objective is to assess the optical properties of TiO₂ and ZnO nanofluids and identify a suitable nanofluid composition capable of effectively separating the solar spectrum to enhance both electrical and thermal outputs. The results show that the TiO₂ nanofluid at 0.04% concentration provides optimal spectral filtering performance, achieving up to a 74 % transmissivity. Additionally, water's inherent transparency between 751–1126 nm makes it an ideal base fluid silicon PV cell’s responsive range. This study establishes a foundation for developing high-efficiency, low-cost SBS-PVT systems with tuneable energy output profiles.
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