Experimental investigations of heat transfer, energy, and exergy-based sustainability of a novel photovoltaic thermal system

The inefficiency of photovoltaic systems is a major obstacle. This research proposes an advanced collector design with dimpled and petal-patterned absorber tubes, coiled twisted tape, and nanofluids combined with nanophase changing materials. The adopted methodology consists of two phases, namely experimentally characterizing the heat transfer performance of the absorber tubes and conducting indoor experiments to evaluate the performance of the new photovoltaic thermal system. The experiments were performed under different flow rates of (0.01–0.085 kg/s), irradiances (400–1000 W/m²), and six different coolants. The initial experiment revealed an inverse relationship between the mass flow rate and the thermal performance of the absorber tubes. However, mass flow rates, solar irradiances up to 1000 W/m², and using various coolants positively impacted the overall performance of the photovoltaic system. The absorber tube with dimples, petal arrays, coiled twisted tape, and nanofluid outperformed the smooth tube with water threefold. Additionally, the photovoltaic thermal system utilizing nanofluids and nanophase changing materials achieved electrical and thermal energy enhancements of 32 % and 21.2 %. The optimal design demonstrated environmental and economic viability, with total output surpassing input energy by 2.11 MWh and net CO₂ mitigation exceeding CO₂ emissions by 0.63 tons.