Drying of untreated Musa nendra and Momordica charantia in a forced convection solar cabinet dryer with thermal storage

Drying uniformity and flexibility in product selection are the primary concern for the end-user in solar drying application. Hence, the present work attempts to determine the user flexibility to choose among different agro-products and simultaneously ensure the drying uniformity inside an active multi-tray indirect-mode solar cabinet dryer. The work considers unripe untreated banana and bitter gourd with an average initial moisture content of 180% (db) and 1328% (db), respectively. The present work tries to assess the influence of a tray-sequencing pattern on the drying behavior at different combinations of flake thickness (0.002 − 0.004 m), multi-tray spacing (0.1 − 0.15 m), tray mesh size (0.01 − 0.015 m), and mass flow rate (0.015 − 0.03 kg/s). For all the tested combinations, the proposed tray sequencing aided to achieve drying uniformity for banana flakes within 10 h and bitter gourd by 18 h. Energy utilization ratio (45.3% − 47.9%) and exergy loss decreased with an increase in mass flow rate. Among the tested combination, 0.03 kg/s, 0.002 m thickness, 0.15 m spacing, and 0.01 m mesh size resulted in higher average energy efficiency (15.34%), and exergy efficiency (60.3 − 94.1%). Further investigations on the proposed dryer are essential to bring out a suitable standardization to attain an upper limit among the agro-products. •Addresses issues of uniform drying and product flexibility in a multi-tray solar dryer.•Evaluates the influence of the proposed tray-sequencing order on the drying behavior.•Factors investigated include moisture content, flow rate, thickness, spacing, and mesh size.•Conclusions were drawn based on EU, EUR, exergy loss, energy, and exergy efficiency.•Proposed tray-sequencing aided to reduce moisture content below 20% for all test conditions.