PERFORMANCE OF A SOLAR DRYER USED FOR TOMATO DRYING

This study tomato (Lycopersicum esculentum L.) samples were pretreated and dried in a solar powered shelf type dryer and simultaneous outdoor drying. The drying test was conducted after setting the drying air speed at 1,25 m/s at the drying chamber entrance and the tomatoes were sliced into equal pieces. The drying process continued until the total tomato weight in the drying chamber reduced to 20 % of the initial weight (5 kg). Both the solar collector efficiency (eta c = 49%) and the system drying efficiency (eta d=26%) were calculated using the heat transfer equaitons. Total of 1,5 kg tomato was sun dried in an open environment. The weight of the sun dried tomatoes were reduced to the 15 % of their initial weight in 36 hours whereas it took 45 hours for the tomatoes in the drying chamber to reduce 20 % of the initial weight. In this study, dried products were compared in terms of drying time, percent weight loss and product quality. The hue angle and chroma values of these samples were found to be 54,69 degrees and 21,92 respectively. Compared with fresh samples, the chroma value is decreased by about 46,45%.