Experimental studies on hemi cylindrical walk-in type solar tunnel dryer for grape drying

A walk-in type hemi cylindrical solar tunnel dryer has been built with heat protective north wall at College of Dairy and Food Science Technology, Udaipur, India for drying agricultural & horticulture product on large scale. In this paper attempt has been made to evaluate the performance of developed dryer to dry the seedless grapes (mutant:Sonaka). The study show that chemically untreated grapes took seven days to dry at 16% (wb) moisture content. The temperature gradient inside the tunnel dryer is about 10–28 °C during the clear day, which is quite sufficient to dry agricultural commodities.