The development of drying system by using parabolic collector for SMEs

Abstract

This research aimed to design, fabricate, and evaluate the mixed mode active solar dryer integrated with a gas burner and compare this with traditional open sun drying for drying agricultural products. This drying system was divided into three main parts. The first part was a parabolic solar collector for solar collection. Second was a solar greenhouse chamber and temperature controller, and the last one was LPG energy used as a reserved heat source for the drying process. Two different experiments were carried out. The first one was solar drying test and the second one was solar hybrid test. The temperature set inside the dryer of the second experiment was at 60°C. When the temperature was lower than 60°C, the controller system automatically turned on the LPG energy source to reach the temperature set. Once the temperature reached the set point, the system automatically turned off the LPG energy source. In the first experiment, the results indicated that the moisture content of Jinda Chili was reduced from 86.25% to 8.33% w.b, while in the second experiment this moisture was reduced from 87.40% to 16% w.b within three days. Both moisture contents of open sun drying were over 70% w.b in the same period. The second experiment was conducted during the rainy season so its moisture content decreased a bit slower than the first one. However, the final values of the moisture contents were still acceptable to the market demand. The expected payback periods of this system for drying Jinda Chili are about 0.45 years.