Sustainable drying of Baccaurea ramiflora using a mixed-mode solar dryer with thermal energy Storage: A comprehensive 4E analysis

Efficient drying systems are essential for preserving perishable agricultural produce, particularly in tropical regions with high humidity. This study explores the applicability of a developed mixed-mode solar drying (MMSD) system by drying Burmese grapes, a highly nutritious fruit found in climatic conditions similar to Northeast India. The MMSD incorporates solar air collectors (SACs) and thermal energy storage with phase change materials (PCM) for enhanced performance. The research provides a comprehensive analysis encompassing energy, exergy, environmental, and economic aspects. Key findings reveal that MMSD achieves mean dryer temperature of 56.26 °C, with a peak of 70.60 °C during solar noon, enabling efficient drying conditions. The Burmese grapes were dried from 5.25 to 0.11 kg moisture/kg of dry content, and shortest drying time of 13 h was observed in case of sample blanched at 70 °C. Energy and exergy efficiencies of SACs are 45.06 % and 42.34 %, respectively, while TES supports extended operation during non-solar hours. The study highlights the long-term sustainability of the MMSD, demonstrating carbon credit revenues and reduced environmental impact. Further, it showcases the system's potential for drying unexploited crops like Burmese grapes while offering a holistic evaluation of its performance, positioning the MMSD as a sustainable solution for tropical agricultural processing.