Performance investigation of a novel multi-tray solar cabinet dryer with multi-point air supply

Abstract

Agricultural produce requires drying for preservation. Employing renewable energy sources, particularly solar energy, can significantly enhance the sustainability of this process. This study seeks to improve the efficiency of a multi-tray solar cabinet dryer by achieving homogenous drying through a multi-point air supply (MPAS). A thorough numerical analysis was performed to examine the thermal aspects of the proposed system using two configurations, namely, a multi-point air supply from two corners and four corners, and to contrast them with those of a conventional dryer. In addition, the numerically optimized system was experimentally tested under controlled indoor conditions to dry bitter gourd (Momordica charantia) slices. Compared to the conventional system, the standard deviation of the temperature profiles across all trays of the proposed MPAS system was reduced by 52.2% and 35.5% for the two-corner and four-corner configurations, respectively, indicating greater uniformity in the heat distribution. Among the two configurations, the MPAS from the two corners exhibited superior heat transfer performance. Furthermore, an experimental study conducted to investigate the drying performance of the proposed MPAS from two corners demonstrated a 23.3% increase in energy efficiency over the conventional system owing to homogenous drying across multiple trays. The average energy utilization was enhanced by 26.3%, with the EUR for the proposed systems reaching 58.5% and 54.2%, respectively. The time required for drying bitter gourd samples was reduced by 22% by introducing a multi-point air supply into a conventional multi-tray solar cabinet air dryer, making it viable for faster agricultural crop drying.