A simple solar dryer has been developed and tested for drying high
moisture rough rice at the experimental farm of Rice Mechanizati n Center
(R.M.C). Meet EI-Oyba. Kafr EI-Sheikh Governorate. The dryer used solar heated air passing by natural c nvection
through a bed of paddy, and from solar radiation incident on the top of the
bed. The results showed that, drying started simultaneously at the top and
bottom of the bed, while the middle layer dried slowest. Periodic stirring of the
bed of paddy reduced the drying time by about 4 hours and led to a uniform
grain moisture content at different layers of the drying bed. The recorded
drying times for solar drying with stirred and unstirred bed were 22 and 26
hours respectively as compared with 46 hours for natural sun drying in open
mats. A significant improvement in final quality of grain dried by the solar
dryer was obvious as compared with the grain dried in open mats specially
broken percentage of milled rice which decreased by about 3.59% for stirred
bed and 2.41% for unstirred bed.