Solar drying of fruits, vegetables, spices, medicinal plants and fish ...

International Solar Food Processing Conference 2009
Fig. 8. Roof integrated solar dryer
3. Mathematical Modeling
Mathematical models are useful for predicting performance and optimal designs of solar drying
systems. The fundamentals of heat and mass transfer during drying are given in Bala (1997a).
The details of heat and mass transfer during drying of chilli in a solar tunnel dryer and roof
integrated solar dryer are given in Hossain (2004) and Hossain et al (2005), and Janjai et al.
(2006) respectively. Mathematical models to simulate the heat and mass transfer in a solar
tunnel drier are discussed below:
Analysis of Collector Performance
Considering an element, dx of collector at a distance, x from the inlet (Fig. 9.), the energy
balances on the collector components give the following equations (Bala and Woods, 1994).
Energy Balances on the Plastic Cover
Energy balance on the cover gives the following equations:
h
( T − T ) + h ( T − T ) + h ( T − T ) − h ( T − T ) = α (1 +τ ρ E (1)
cam c am ca c a rcs c s rpc p c cS cS pS
)
9