Postharvest drying is a critical step in reducing agricultural losses and ensuring food quality, especially in off grid and low-resource regions. This review uniquely explores the integration of solar and wind energy with thermal energy storage (TES) to overcome the intermittency challenges of renewable energy in agricultural drying. Drawing on over 100 studies, it evaluates system configurations, drying principles, and energy transfer mechanisms across various crops, with particular attention to heat-sensitive produce like herbs and fruits. Evidence shows that hybrid systems incorporating TES can achieve up to 70% energy savings and reduce drying time by 50–80%, while improving nutrient and aroma retention. The review categorizes and compares solar dryer types direct, indirect, and mixed mode and assesses passive and active wind-assisted drying for their role in enhancing convective transfer. It also analyzes TES materials (sensible and latent heat) and their integration strategies to stabilize temperature and extend drying cycles. Emerging smart dryers with IoT, AI-based controls, and CFD-optimized designs are discussed alongside their socioeconomic implications for low- and middle-income countries (LMIC). The article identifies key research gaps, including the need for harmonized performance metrics, field-scale validation, and locally manufactured modular systems. This interdisciplinary synthesis informs the development of scalable, climate-resilient drying solutions to enhance food security and rural livelihoods.
Barzigar et al. (2025) studied this question.