Mathematical Modelling of Solar Tunnel Dried Ginger (Zingiber officinale L.) Slices

Drying characteristics of ginger (Zingiber officinale L.) slices were investigated in an experimental solar tunnel dryer (STD). Ginger with three different slice thicknesses of 3, 5, and 7 mm were dried at three temperatures of 50°C, 55°C, and 60°C. Effects of drying time on moisture ratio of sliced ginger samples were evaluated. To design, improve efficiency, analyse and forecast the performance of sun drying systems for drying ginger slices, different models, viz., Page model, Lewis model, Henderson-Pabis model, Wang Singh model, Verma model, Approximation Diffusion model, Logarithmic model and Hii, Law & Cloke model were applied. Models were validated based on determination of coefficient (R²), chi-square (ꭓ²) and Root Mean Square Error (RMSE) between the experimental value and predicted value of moisture ratios. Hii, Law & Cloke model was found as the best fit model, representing an appropriate tool for estimation of the drying time. Hii, Law & Cloke model resulted in values of R², ꭓ², and RMSE as 0.9994, 0.0039 and 0.0061, respectively, at 55°C for 3 mm slice thickness. Moisture ratio predicted by modelling suggested 55°C drying temperature with the 3 mm slice thickness as the suitable combination for drying in a solar tunnel dryer. This study demonstrates the enhanced efficiency and reliability of solar tunnel dryers over traditional sun drying methods, offering a more controlled and quicker drying process, which can significantly benefit agricultural and industrial applications.