Convective hot air drying of grapes: drying kinetics, mathematical modeling, energy, thermal analysis.

This study aimed to evaluate the experiment of drying grapes that applied three different airflow patterns: vertical and two horizontal (HMP-1 and HMP-2) inside convective hot air dryers. Experiments were conducted using a forced convection dryer at 40–60 °C and air velocities range of 1.0–2 m s−1 to dried grapes. The drying time was significantly decreased due to the greater air velocity and temperature at different dryers. The horizontal dryer (HMP-2) exhibited the lowest significant drying time reduction of 3.79 and 8.46% lower than the horizontal (HMP-1) and vertical airflow patterns, respectively. Compared to the vertical dryer, the horizontal (HMP-2) dryer had the maximum thermal efficiency in the range of 50.31 to 74.52% and the lowest in the 29.77–52.45% range. The minimum specific energy consumption of 27.44 MJ kg−1 was recorded using the horizontal (HMP-2) dryer, which was 53.82% and 141.91% lower than horizontal (HMP-1) and vertical, respectively. Additionally, implementing the horizontal (HMP-2) dryer for drying grapes has many advantages over the vertical dryer, including faster operating times, lower overall energy consumption, and improved dryer thermal efficiency. [ABSTRACT FROM AUTHOR]