Abstract:
The objective of this thesis was to study the effects of hot air temperature and velocity on the kinetics, energy, and exergy of drying long pepper using a tray dryer. The research also studied the mathematical model for predicting the dehydration of long pepper. The experiment used long pepper with an initial moisture of around 246-253 % (d.b.). The hot air temperatures of 70, 75, and 80°C and the hot air velocities of 0.5, 0.7, and 1 m/s were the experimental conditions of this research. The energy efficiency was analyzed based on the first law of thermodynamics, and the second law of thermodynamics was applied to the analysis of exergy inflow, exergy outflow, and exergy loss. The results showed that drying long pepper at a hot air temperature of 80°C and a hot air velocity of 1 m/s caused the moisture to decrease faster than drying at other conditions. The moisture content dropped quickly during the first phase of drying, then gradually decreased. The increase in the hot air temperature resulted in an increase in energy and exergy efficiency, while the increase in the hot air velocity did not affect energy and exergy efficiency. The highest energy efficiency was 22.56%, and the highest exergy efficiency was 93.35%. The empirical model performed well in predicting the drying moisture ratio. In all experimental conditions, it was concluded that the model of Midilli et al. was able to predict the drying characteristics appropriately, with the highest accuracy and closest to the experimental results. This is due to the fact that the decision coefficient (R2) was the highest with an R2 value between 0.9969 and 0.9997, and the root square of the mean square error (RMSE) was the lowest with an RMSE value between 0.0062 and 0.0159.