Progress in Smart Solar Drying Technologies and the Sustainability of Drying Systems: Systematic Review

Smart solar drying technologies have been identified as an ideal solution to reduce food waste. Their ability to optimize, monitor and control the drying process in real time promotes the performance of the drying systems. This systematic review evaluates recent advancements in smart solar technologies, emphasizing the enhancements in system communication, remote control, automation, synchronization and optimization. Modern modeling methods have been comprehensively discussed with specific examples to demonstrate their contribution to the performance of solar drying systems. The review gives special attention to analysis on the sustainability aspects of smart solar dryers, highlighting critical economic, technical, social and environmental indices. Experimental results have shown that the smart solar drying technologies have improved the overall dryer efficiency by 9.81%–46.43%, reduced drying time by 40%–60% and improved color retention. Besides, the analysis from this study reveals that smart solar dryers are economically viable and environmentally friendly with a dryer payback time of 0.32–2.476 years and a carbon dioxide mitigation factor of 8.55–140.811 t/lifetime. Additionally, these drying systems have exhibited excellent potential to promote the green economy with better records of improvement potential (4.205–11.7 W), waste energy recovery (0.755–0.84) and sustainability index (1.195–2.09).