Comparative Efficiency of Solar Dryers in Post-Harvest Grain Preservation

Thesis Abstract

The efficient preservation of grains post-harvest remains a critical challenge in ensuring food security and reducing post-harvest losses, particularly in regions where conventional drying methods are limited by climate variability and resource constraints. This study aims to compare the operational efficiency, cost-effectiveness, and overall preservation quality of different solar dryer systems—namely indirect solar dryers, direct solar dryers, and hybrid solar dryers—used in grain drying processes. The specific objectives include assessing the drying performance based on parameters such as drying time, moisture content reduction, and energy consumption; evaluating the impact of each drying method on grain quality attributes like germination rate, fungal contamination, and nutritional content; analyzing the economic viability of each system; and identifying the environmental implications associated with their use. The research employs a mixed-methods approach with a primarily quantitative design, underpinned by the Systems Theory to understand the interactions between technological, economic, and environmental factors influencing dryer performance. The study is conducted within a grain-producing region with a diverse agricultural economy, and involves a sample of 150 grain drying units—50 units per dryer type—selected through stratified random sampling from a registry of registered solar drying facilities. Data collection instruments include structured observation checklists, moisture meters, grain quality assessment kits, and economic evaluation questionnaires. Data validity and reliability are ensured through pre-testing of instruments, inter-rater reliability assessments, and calibration of measurement tools. Quantitative data analyses involve descriptive statistics, Analysis of Variance (ANOVA) to compare performance metrics, and regression analysis to identify factors influencing drying efficiency. Additionally, cost-benefit analysis evaluates economic viability, while life cycle assessment provides insight into environmental impacts. The anticipated findings suggest that hybrid solar dryers outperform both direct and indirect systems in reducing drying time and moisture content, resulting in higher preservation quality, with the added benefit of lower fungal contamination and retention of nutritional value. Economically, hybrid systems demonstrate improved cost-efficiency through reduced operating costs over time, despite higher initial investments. Environmental analysis indicates that all solar dryers have significantly lower carbon footprints compared to conventional fuel-based drying methods, with hybrid systems offering the most sustainable solution due to their integrated energy recovery features. This research contributes to the existing body of knowledge by providing a comprehensive, empirical comparison of solar drying technologies tailored to tropical grain production contexts, addressing the gap in comparative analyses of hybrid systems’ efficiency and sustainability. The findings will inform policymakers, agricultural extension officers, and farmers on selecting optimal dryer technologies for post-harvest management, emphasizing technical performance, economic feasibility, and environmental sustainability. The study concludes that hybrid solar dryers offer a promising avenue for enhancing grain preservation, reducing post-harvest losses, and promoting sustainable agricultural practices. Recommendations include promoting investments in hybrid solar dryer infrastructure, enhancing user training to optimize dryer operation, and further research into integrating renewable energy sources for granular drying processes. Future studies could explore long-term performance assessments and scalability of hybrid systems across different agro-ecological zones, thereby advancing the development and adoption of sustainable grain preservation technologies.