SUSTAINABLE CROP PRESERVATION: A COMPREHENSIVE REVIEW OF INTEGRATED SOLAR AND BIOMASS HYBRID DRYERS

Abstract

Post-harvest spoilage remains a critical challenge for global food security, particularly in tropical regions where traditional open sun drying is hindered by weather dependency, slow drying rates, and contamination risks. This paper presents a comprehensive review of integrated solar and biomass hybrid dryers as a sustainable solution for continuous, year-round crop preservation. By synthesizing recent advancements in dryer configurations—including greenhouse, cabinet, and tunnel designs—this review evaluates how the integration of biomass burners and thermal energy storage units addresses the intermittent nature of solar energy.
Analysis of current literature reveals that hybrid systems can consistently maintain drying chamber temperatures between 65°C and 80°C, significantly reducing drying times for high-moisture crops like mangoes, coconuts, and peppers to a 2–3 day window. Key technical innovations are examined, specifically the implementation of tray baffles to enhance airflow uniformity and the application of Computational Fluid Dynamics (CFD) for thermal optimization. Furthermore, the review discusses the efficacy of various mathematical models, noting that the Henderson and Pabis thin-layer model provides superior accuracy in predicting drying kinetics for most tropical products. The findings demonstrate that while hybrid solar-biomass technologies improve thermal efficiency (reaching levels of 29-30%) and preserve vital nutritional content like Vitamin C, further research is needed to optimize biomass heat exchanger designs and automate control systems. This study serves as a technical roadmap for researchers and stakeholders aiming to implement decentralized, renewable drying solutions in the agricultural sector.