Research Article
Performance Comparisons of Solar Mixed and Indirect Dryers for Maize Grain Drying
@INPROCEEDINGS{10.1007/978-3-030-15357-1_12, author={Aynadis Molla and Sajid Alavi and Bhadriraju Subramanyam and Solomon Workneh and Nigus Gabbiye}, title={Performance Comparisons of Solar Mixed and Indirect Dryers for Maize Grain Drying}, proceedings={Advances of Science and Technology. 6th EAI International Conference, ICAST 2018, Bahir Dar, Ethiopia, October 5-7, 2018, Proceedings}, proceedings_a={ICAST}, year={2019}, month={3}, keywords={Drying rate Dryer efficiency Solar dryers}, doi={10.1007/978-3-030-15357-1_12} }- Aynadis Molla
Sajid Alavi
Bhadriraju Subramanyam
Solomon Workneh
Nigus Gabbiye
Year: 2019
Performance Comparisons of Solar Mixed and Indirect Dryers for Maize Grain Drying
ICAST
Springer
DOI: 10.1007/978-3-030-15357-1_12
Abstract
This paper presents the design, construction and performance evaluation of mixed (SCMD) and indirect (SCID) -mode solar cabinet dryers for drying of maize grain with varieties of BH-540 and BH-660. The performances of the solar dryers were tested with three levels of sample loading, 21.74 kg/m (thick layer), 16.3 kg/m (medium layer), and 10.87 kg/m (thin layer). In both dryers, the air was heated in the solar collector and passed naturally through a grain bed. For SCMD, the drying cabinet absorbs solar energy directly through the transparent roof. The solar irradiance, temperature and relative humidity distribution for ambient and in different parts of the dryer, and moisture loss of the grain at each try have been recorded. The result revealed that, a temperature raise of 15 °C was found in both dryers with respect to the ambient air. The required drying time was varied depending on the amount of sample loaded. About 32 h was required in thin layer compared to 53 h in thick layers drying process to reduce the moisture content of the grain to its safe storage value of 13% (w,b). The drying rate, collector efficiency and overall system efficiency were varied from 0.41–0.56, kg/h, 44.4–57.2%, and 24.0–32%, for SCID and from 0.47–0.58, kg/h, 44.4–57.2%, and 24.6–33%, for SCMD respectively. Statistically, no significant difference has observed on drying rate and overall dryer efficiency between SCMD and SCID.