Keywords : Mixed-mode solar dryer
Engineering and Technology Journal,
2020, Volume 38, Issue 8, Pages 1214-1225
This paper proposes a developed numerical and experimental design of a hybrid Photovoltaic-Thermal (PVT) double-pass counter-flow system connected with the mixed-mode solar dryer system. The mixed-mode solar dryer considers the most efficient mode because it has two heat sources, from solar radiation and the hot airflow which is supplied by the PVT system. The PVT system is often unused for drying applications; therefore, the whole proposed PVT solar system in this work is utilized for drying applications. This system is not only massive fuel savings, but also crucial to improve the quality of the dried product in terms of color, aroma, and taste. To verify the effectiveness and robustness of the proposed system, the system is utilized to dry 300g of slices of banana, where the obtained range of air temperature is from 43.2 to 60.2°C. The slices of banana are distributed identically between upper and lower trays. The initial moisture rate of banana was about 78%, and the most dropped in moisture content was from 78% to 28.12% in the lower tray at 0.031kg/s after 8 hours of the drying process. It was noticed that the most and least decreasing in weight of banana samples was from 150 to 48g and from 150 to 55g in lower and upper tray, respectively, at 0.031 and 0.017 kg/s mass flow rate. This gives an indication that the highest reduction was 68% of banana weight at a high mass flow rate of airflow. The critical parameter such as temperature distribution of the PVT with dryer room, useful heat gain, and thermal efficiency are computed by using the MATLAB 2015b program which is built for this purpose. The highest heat gain and thermal efficiencies were 423.7 and 52.98%, respectively, at 1:00 PM when the mass flow rate 0.031 kg/s.