Performance Evaluation of Solar Tunnel Dryer for Drying Red Chilli using Taguchi L27 Orthogonal Array

The Solar Tunnel Dryer can provide the best alternative method to dry red chillies in less time. The performance of the solar tunnel dryer depends on various parameters such as ambient temperature, solar radiation intensity, wind velocity, relative humidity, temperature of air inside the solar tunnel dryer etc. The experimentations are carried out at Umrer in Vidarbha region of Maharashtra. In this work Solar Tunnel Dryer (STD) performance is investigated by varying different process parameters, which includes absorber material (ABM), polyethene cover thickness (CT), air flow velocity over drying bed (AFV) and drying layer thickness (DLT). Three different levels of each parameter are chosen to form different combinations of experiments using Taguchi L27 orthogonal array with three interactions in between ABM×CT, ABM×AFV, and ABM×DLT. Total 27 experiments are designed and fabricated for drying 5 kg of red chilli. The initial moisture content of red chilli is 80% which is reduced to 5%. The efficiency, total moisture removed and drying time of individual STD are investigated. Considerable reduction in drying time and better quality of dried products are observed as compared to open sun drying.