Study on Using Solar Greenhouse Combined with Tray Dryer for Vegetable and Fruit Drying

บทคัดย่อ

This research was conducted to study the use of a solar greenhouse dryer combined with a tray dryer using liquefied petroleum gas (LPG) as an altermative heat source for vegetable and fruit drying. Dimensions of the solar greenhouse dryer, which was covered by polycarbonate, were 6.00 m x 6.00 m x 1.80 m (w x l x h). The dimensions of the tray dryer were 1.22 m x 2.44 m x 1.22 m (w x l x h). There were 20 stainless screen trays for
placing the material being dried. The dimensions of each tray were 0.75 x 1.00 m (w x l). Approximately 30-60% of returned hot air was mixed with fresh air for reducing energy consumption. The drying test capacity of Hua-rue chili and Namwa banana was 100 kg. The drying testing result of Hua-rue chili was that the chili was dried from 78% moisture content to 12%. The tray dryer was set at 60oC with drying time of 8 hr. After that the chili was
solar dried in the greenhouse for 2 sunny days. The Namwa banana was dried from 61% moisture content to 22% by the process was tray dryer set at 75oC drying time 10 hr then fermenting storage 10 hr and dried in the greenhouse for 2 sunny days.