Document Type : Original Article
Author
M.sc. Biosystem engineering, Mohaghegh Ardabili University, Ardabil, Iran.
Abstract
One of the main problems of crops dryers is their high cost, high energy consumption, and the associated higher cost of operation. The solution proposed for this problem is use of the free and clean solar energy. In this study, a solar dryer was developed, which consisted of a solar collector that innovatively is made of discarded waste materials such as cold drinks metal cans. Also Phase change materials (PCM), was included in the dryer chamber for energy storage, and was tested under laboratory conditions, and air flow rate, temperatureand radiation intensity were measured. According to the results, the temperature of the absorber plate of the innovatively solar collector increased up to 111 ºC and the temperature of the exhust air had a difference of 50 to 60 ºC compaed to the ambient temperature. Highest tempratur increase was obtained with air velocity of 0.5 m/s at 2- 3 PM in test days. The phase change temperature of the materials occurred at 51 to 53 ºC. When the chamber temperature exceeded 53 ºC, the material’s phase changed and the stored heat was directed to dryer in order to compensate for the tempratuer drop in the plenum. . As result, the temperature loss of the drying chamber occurred less severly under the phase change material conditions, because it slightly prevented temperature loss. Finally, mintdrying test was carried out. The mint with an initial miostuer content of 86 percent, lost 86g of its moisture and reached final moister content of 12 percent during the product test in 273 minutes, under mean chamber temperature of 44.3 ºC and air velocity of 0.5 m/s.
Keywords
Part B. Econ. Plann. Policy. 1, 85-95
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