This paper presents a transient analytical model for an inclined multi-pass solar air heater with in-built thermal storage and attached with the deep-bed dryer. The performance of a solar air heater was evaluated for drying the paddy crop in a deep bed by using an appropriate deep-bed drying model. A parametric study was done for a day of the month of October for the climatic condition of Delhi (India). The effect of change in the tilt angle, length and breadth of a collector and mass flow rate on the temperature of grain have been studied. The rate of moisture evaporation and humidity of the drying air have been analyzed with the drying time for different depth of the grain bed. It has been observed that the bed moisture content decreases with the time of the day. The humidity of the air and the drying rate increases with the increase in the depth of drying bed. (C) 2004 Elsevier Ltd. All rights reserved.