Solar dryer technology is simple and therefore easily adoptable by the household, community and food processing sector. Mixed mode type of solar dryers have been designed, fabricated and tested for drying of food products like papad, potato wafers, banana wafers, grapes, onion, garlic, ginger, red chilies, methi leaves, mushrooms etc. at CSIR-CSMCRI, Bhavnagar. The capacity of the dryers can be varied from 5-20 of kg of raw material per batch, however it depends on the nature of the food to be dried. The drying of various food products can be achieved in about half the time duration taken for open sun drying. Based on the small-scale design, a 0.6 T/batch dryer was installed at Sagar Island for drying of freshly caught fish.

Benefits of solar thermal dryer include:

• Since the food is enclosed it is therefore protected from dust, insects, birds, flies and wandering animals.
• Higher temperature reduces the risk of spoilage due to microorganisms.
• The unit is waterproof and thus the product need not be moved when it rains or at night
• The unit can be constructed form the locally available materials.
• Sometimes in open sun drying color of the product changes because of direct sun light exposure. In a solar dryer the color of the product is retained as the product is not directly exposed to sunlight.
• Less risk of spoilage because of the speed of drying, as because, slow drying has tendency to result in fermentation and spoilage
• The quality of the product is better in terms of nutrients and hygiene.