DESIGN, CONSTRUCTION AND PERFORMANCE STUDY OF AN INDIRECT TYPE SOLAR DRYER FOR FOOD PRESERVATION

Abstract

Utilizing the most abundant and free of cost energy of the sun to heat up the air and to use that heated air to dry foods is the main goal of this thesis. In order to do this an indirect type forced convection solar dryer is fabricated with components like screen absorber solar collector, drying chamber, fan, etc. The performance of the designed solar dryer is evaluated by carrying drying experiments with potatoes. The temperature inside the drying chamber ranges from 490C to 580C while the ambient temperature ranges from 33 0C to 350C. Initial moisture content in potatoes ranges from 77-79% and the final moisture content obtained about 15.44% in 7 hours. Solar drying of potatoes is carried for forced convection and is compared with open solar drying. The drying rate was 0.1223 kg/hr and 0.1173 kg/hr in solar dryer and open sun drying method respectively. It is seen that applying indirect solar drying not only reduce the drying time, but also higher quality of dried products can be obtained.