Performance Evaluation of a Mixed-Mode solar dryer with PCM-based energy storage for efficient drying of Baccaurea ramiflora

Abstract

A novel mixed-mode solar dryer (MMSD) integrated with a phase change material (PCM) and a drying capacity of 15 kg was designed and developed to efficiently dry Baccaurea ramiflora (Burmese grapes). The system’s performance was evaluated for three sample types: untreated and blanched at 70 °C (BG70) and 80 °C (BG80), under two conditions: within the solar dryer and open sun drying. Blanching treatments significantly reduced drying time by 5–7 h, with BG70 achieving the shortest drying duration of 13 h. The incorporation of PCM extended the dryer’s operational time by an additional two hours, enabling sustained drying under suboptimal solar conditions. Moisture content in all cases was reduced from 84 % to 10 % on a wet basis. Drying kinetics were analyzed using eight models, with the Midilli and Kucuk model demonstrating the best fit due to its highest R², lowest RMSE, and reduced chi-square values. Among the samples, BG70 showed the maximum evaporative heat transfer coefficient of 2.33 W/m²K. Quality analysis indicated that solar-dried samples retained superior attributes compared to open-sun dried samples. The study’s novelty lies in the integration of MMSD with a latent heat storage unit for drying less common fruits like Burmese grapes, offering enhanced efficiency and product quality. By assessing the impact of blanching and controlled drying conditions, this research addresses a crucial gap in solar drying literature, providing a sustainable solution for the climatic conditions similar to the north-eastern region of India.