An experimental investigation on a locally fabricated dryer integrated with a novel solar air heater for the drying of potato slices

Typical fuel-driven commercial dryers have excellent efficiency with homogeneous high-quality output, but they are beyond the access of farmers with limited agro land and financial resources. In this study, drying trials with potato slices were carried out utilizing a laboratory scale bunt drier coupled with an unique solar air heater. Assuming the set-up as mixed mode type solar dryer, performance of the dryer during the drying of potato slices was studied and the results were compared with that of open sun drying (OSD). The novel two pass solar air heater used in this project has aluminum turbulators arranged in staggered fashion. The absorber plate with aluminium turbulators present inside the double pass solar air heater reached a maximum temperature of 68 degrees C. The average efficiency of the novel solar heater was about 72%. The moisture content of potato was reduced to 18.23% in 8 hours from 82.15%. The maximum thermal efficiency of the dryer was determined as 34%.The average specific energy requirement was estimated as 1.61 kWhkg(-1) and the shrinkage ratio was found to be 0.2 at the end of 7 hours.