ISI BILIMI VE TEKNIGI DERGISI-JOURNAL OF THERMAL SCIENCE AND TECHNOLOGY, cilt.34, ss.99-109, 2014 (SCI İndekslerine Giren Dergi)
This experimental study was performed to determine drying characteristics of the Capsicum Annuum in a solar tunnel dryer with forced convection and in open sun drying process at the open field. Solar tunnel dryer consists of two solar air collectors connected in series, a greenhouse type tunnel dryer and an air circulation system. Heated air obtained from solar air collectors was forced towards the Capsicum Annuum by a blower during the drying process. During the period of drying, the moisture ratio of the Capsicum Annuum versus the drying time was measured in the presence of different data such as solar radiation, relative humidity and temperature of ambient air, inlet and outlet air temperature of the solar air collectors, inlet and outlet temperature and relative humidity of the tunnel dryer. Drying curve was formed for solar tunnel drying and open sun drying on the bases of the variation graph of moisture ratio and drying time of the Capsicum Annuum. Suitable mathematical model was examined by using non-linear regression method. To this end, ten different mathematical models were compared according to statistical parameters such as the chi-square error (chi(2)), the root mean square error (RMSE), the mean bias error (MBE), the coefficient of determination (R-2). As a result, it was observed that the model which provides the best description of the solar drying behavior of the Capsicum Annuum is the two-term drying model. This model resulted in chi(2) = 0.0006, RMSE = 0.0061, MBE = 0.0190, R-2 = 0.9988 for forced solar drying, and chi(2) = 0.0004, RMSE = 0.0082, MBE = 0.0128, R-2 = 0.9940 for open sun drying.