CONCLUSION
The objective of this review is to emphasis the important of tray dryer design in drying of agricultural product. Several designs can be implemented to improve tray dryer performance, increases quality of dried product and produces uniform drying. For the stationary tray dryer, the semi-continuous mode or exchange of the position of the tray can be executed to obtain uniform drying. The rotating/moving tray dryer can also produce more uniform drying. In general, re-circulation of drying air and mixing with fresh air reduces energy consumption. However, for certain products, it may decrease the product quality and thus appropriate recycle fractions must be applied. The use of solar energy for drying agricultural product will make the dryer system run at low operating cost. Therefore the solar dryer is widely use for drying agricultural product and will be the future trends. The drying chamber configuration can be optimized by CFD simulation to predict the airflow distribution throughout the drying chamber. Nowadays, given the increase in computing power, the application of CFD can be a valuable tool for engineering design and analysis of solving complex fluid flow, addressing heat and mass transfer phenomena, aiding in the better design of tray dryers and produce high quality of dried product.