Energetic and exergetic investigation of a mixed flow dryer: A case study of maize grain drying

Abstract

Evolution of energetic and exergetic performance is an important concern for selecting suitable dryer for any drying process. This paper attempts to observe performance evaluation in terms of energy and exergy analysis of a mixed flow dryer for drying of freshly harvested maize grain. Existing models in regard to energy and exergy that were established by investigating the first law and second law of thermodynamics were applied for this study. Grain drying experiments executed for 40–80 °C drying temperature at 3.0 and 6.0 m/s air velocity. Energy utilization ratio decreased with increase of drying temperature at 3.0 m/s air velocity while differing surveillance was noticed for 70 and 80 °C at 6.0 m/s air velocity. Energy efficiency of the research mixed flow dryer vacillated from 26.52 to 71.75% over the temperature range. The magnitude of exergy inflow, exergy outflow and exergy loss varied as increasing trend with the upturn drying temperature. The analysis shows that exergy efficiency and exergetic improvement potential varied between 8.54 and 20.87% and between 0.81 and 11.12 kJ/s, respectively for mixed flow maize drying. Model equations that could aptly illustrate the energetic and exergetic parameters were developed as a function of drying temperature.