CFD-driven design and energy-exergy optimization of an IoT-based tracking solar collector for tomato drying

This study investigates the performance of an advanced tracking collector solar dryer (TCSD) enhanced with IoT monitoring and a photovoltaic (PV) system for efficient tomato slice drying. The novelty of this study lies in the development and integration of an Arduino-based IoT tracking solar collector (TSC) and drying room (DR) for the efficient drying of tomato slices. This smart tracking mechanism allows the solar collector to dynamically adjust its position to maximize solar energy capture throughout the day, thereby enhancing thermal efficiency. It further distinguishes itself by combining computational fluid dynamics (CFD) simulations with detailed thermal analyses—specifically energy, exergy, and sustainability indicators—to provide a more comprehensive and scientifically rigorous assessment of the solar dryer's performance. The TCSD was tested with tomato slices of 4-, 6-, and 8-mm thicknesses, while three airflow rates (0.016, 0.032, and 0.048 m³/s) were evaluated to determine the most effective drying conditions. Drying tomato slices with a thickness of 4 mm significantly reduced the drying time by 25% and 33.3% compared to slices with thicknesses of 6 mm and 8 mm, respectively. CFD results revealed that an airflow rate of 0.016 m³/s provided the most uniform air distribution and achieved a peak drying temperature of 70.53 °C. This configuration minimized heat loss and ensured consistent moisture removal. Over three consecutive drying days (8 am − 6 pm), the system demonstrated stable thermal performance, with the TSC reaching energy efficiencies between 35% and 61.3%, while the overall TCSD efficiency ranged from 10.7% to 15.16%. Exergy analysis further highlighted the system's thermodynamic effectiveness, with TSC exergy efficiency ranging from 3.28% to 22.16% and the DR achieving 32.16% to 58.66%, indicating efficient energy utilization. Sustainability was assessed through key indicators: Improvement potential (IP: 17.36% and 30.48% of the total input exergy), waste exergy ratio (WER: 0.68 − 0.83), and sustainability index (SI: 1.76–2.42), confirming the dryer's eco-friendly operation. The integration of IoT technology enabled real-time monitoring of temperature, humidity, and airflow, ensuring precise control over drying parameters. The findings demonstrate that the TCSD system optimizes solar energy use, reduces drying time, and enhances product quality while maintaining low environmental impact.