A convective batch tray dryer with hot air recycle was modeled with a drying characteristic curve and series tank model expressing an incomplete air flow in a drying chamber. An estimation method for performance of the dryer was introduced through simulation of the dryer model. Simulation was made with a combined conductive-convective drying process with hot air at 433 K or 363 K. Concurrently with the above, a wide range of humidity was simulated by using a drying characteristic curve of a wet glass-particle layer obtained from combined conductive-convective drying with hot air at 323 K and low humidity. The effects of hot air temperature, air flow rate, recycle ratio, and tank number on overall drying time, total drying energy, excessive drying of layer, and humidity in the drying chamber and the performance of the dryer were found to change greatly at the border values of 373 K for hot air temperature and 0.95 for recycle ratio.