Keywords: thin layer drying, Fenugreek leaves, solar tunnel dryers, exergy efficiency, energy efficiency, drying kinetics, Kasuri Methi, leaf drying, moisture content, kinetic modelling
Energetic and exergetic analysis of walk–in type solar tunnel dryer for Kasuri Methi (Fenugreek) leaves drying
This study investigated thin layer drying characteristics of Fenugreek leaves in a walk–in type of solar tunnel dryer. Fenugreek leaves were dried from a moisture content of 89% (w.b.) to 9% (w.b.) in 16 h (two days). The obtained drying data were fitted to 11 different drying kinetics models. Of these, the model suggested by Verma et al. (1985) had the best fit with the drying behaviour of Fenugreek leaves. In addition, the thermodynamic behaviour of a walk–in type solar tunnel dryer was evaluated. The energy efficiency during the study varied from 0.841% to 1.613%. The exergy inflow and exergy outflow was varying from 16.35-25.01 kJ/kg to 0.23-1.167 kJ/kg, respectively. The exergy efficiency of the drying system ranged between 0.018% and 0.102%.