OPTIMIZATION OF PROCESS PARAMETERS OF SOLAR TUNNEL DRYER FOR DRYING RED CHILLI USING TAGUCHI METHOD AND GREY RELATIONAL ANALYSIS

The purpose of this study is to determine the optimum level of the process parameters of the solar tunnel dryer (STD) for drying red chilli using the Taguchi experimental design method. In the study, the effects on quality characteristics, i.e. the efficiency of the solar tunnel dryer and quality of dried chilli products is investigated using different solar tunnel dryer process parameters and their levels. These parameters include the absorber material, semitransparent cover thickness, air velocity over drying bed, and drying bed thickness. The experiments are conducted according to Taguchi L9 orthogonal array (34). The optimum parameter combination is obtained using the analysis of signal to noise ratio and the levels of process parameters influencing the quality characteristics are determined by using analysis of variance (ANOVA). The optimal combination of processing parameter levels is determined by grey relational analysis. As per the response graph for grey relational grade, air flow velocity over drying bed is the most significant factor that affects the efficiency of solar tunnel dryer and quality of dried chilli. The overall quality can be effectively controlled by controlling the only parameter.