In the quest for sustainable agricultural practices, researchers have turned to the sun for innovative solutions, and a recent study published in *Scientific Reports* offers promising insights into optimizing solar drying techniques for crops like stevia. The research, led by Abdallah Elshawadfy Elwakeel from the Agricultural Engineering Department at Aswan University, delves into the environmental and energetic sustainability of drying stevia leaves using a photovoltaic thermal–indirect solar dryer (PVT-ISD). The findings could have significant implications for the agriculture sector, particularly in regions with abundant sunlight.
The study explored how the position of trays within the drying chamber and varying airflow rates affect the drying process. By using six trays at two different airflow rates—0.08 and 0.13 cubic meters per second—the researchers found that the lowest tray, closest to the hot air inlet, achieved the fastest drying times, especially at the higher airflow rate. This configuration reduced the final moisture content of the stevia leaves to just 5.7%, a critical factor for preserving the plant’s valuable compounds.
Energy and exergy analyses revealed that the solar collector’s thermal efficiency peaked at 55.7% at the higher airflow rate, while the exergy efficiency of the solar collector reached up to 14.68%. Interestingly, the drying room performed better at the lower airflow rate, with a maximum exergy efficiency of 37.89%. “The trade-off between airflow rates and efficiency highlights the importance of optimizing drying conditions to balance energy use and performance,” Elwakeel noted.
Sustainability and environmental indicators further underscored the benefits of higher airflow rates for the solar collector, with notable reductions in environmental destruction coefficients, impact factors, and effect factors. These findings suggest that adjusting airflow rates and tray positions could enhance the overall sustainability and environmental performance of solar drying systems.
The commercial implications of this research are substantial. For the agriculture sector, particularly in sun-rich regions, adopting optimized solar drying techniques could lead to more efficient and sustainable processing of crops. This could reduce reliance on fossil fuels, lower operational costs, and minimize environmental impact, making solar drying a more attractive option for farmers and agribusinesses.
As the world continues to seek sustainable solutions to meet growing food demands, research like this paves the way for innovative technologies that harness renewable energy. “By fine-tuning the parameters of solar drying systems, we can achieve better efficiency and sustainability, which is crucial for the future of agriculture,” Elwakeel added.
The study, published in *Scientific Reports* and led by Abdallah Elshawadfy Elwakeel from Aswan University, offers a glimpse into the potential of solar drying technologies to revolutionize agricultural practices. As the sector continues to evolve, these findings could shape the development of more efficient and environmentally friendly drying methods, ultimately benefiting farmers, businesses, and the planet.