Beschreibung
Rice is one of the major staple foods worldwide, constituting about 25% of the total global cereal production in 2019. A common practice after harvesting paddy rice is drying. This process is carried out to avoid the spoilage of the crop and to allow longer-term storage. Sun drying remains the most common method of drying the rice, the success of which depends largely on high solar radiation availability. However, in humid tropical countries such as the Philippines, the sun drying method is challenging and can compromise the quality of rice. Therefore, the development of a solar dryer for paddy rice was the focus. This work was carried out in collaboration with the International Rice Research Institute (IRRI) and Grainpro Philippines Inc. Three studies were generated through the development of the solar dryer. In the first study, Albedo was investigated. This important factor provides insights into the absorbed and reflected solar radiation ratio. This knowledge applies to solar drying technology. Thus, a semi-empirical albedo model was integrated into a 1D thermal model describing the heat and mass transfer during sun drying paddy rice. In the second study, an inflatable solar dryer (ISD) was developed. ISD is manufactured with a transparent UV-treated polyethylene film and reinforced polyvinyl chloride film joined by a heavy-duty zipper. In the third study, a collaborative model was developed to study the airflow distribution inside the ISD using ANSYS fluent. On the other hand, a thermal model was developed in MATLAB/Simulink to simulate heat and mass transfer in the drying area. The validated models were used to predict the ISD's air velocity distribution and the performance of the drying process of paddy rice under different weather conditions.
