Improvement of an open sun drying system for dried banana product using solar tracking system: a case study in Thailand

摘要

ABSTRACT This paper proposes an open sun drying (OSD) system for dried banana products using automatic dual-axis solar tracking. A pseudo-azimuthal mounting structure is implemented to rotate around the primary (daily angle) and secondary (elevation angle) axes. The proposed drying system uses a simple light-dependent resistor (LDR) orientation to control the rotating axes and follow the sun trajectory. The rotation in the primary axis adjusts the daily angle from east to west, which changes each hour. The secondary axis is rotated for the elevation angle from north to south direction, a seasonal change. The experiment was conducted at the Faculty of Engineering and Technology, King Mongkut’s University of Technology North Bangkok, Rayong Campus, Rayong province, Thailand, to validate the performance of the proposed system compared with two conventional OSD systems: horizontal flat-plate and tilted. The effect of the solar tracking system on the drying characteristics of dried bananas is evaluated by considering moisture content, moisture ratio, drying rate, and drying time. The experimental results demonstrate that the proposed drying system can reduce the drying time for banana products compared with the tilted system by 18.87% and the horizontal flat-plate system by 21.82%. Moreover, the experiment reveals that the electrical energy consumed by the proposed drying system is only 32.26 Wh/day. Finally, the economic analysis confirms that the payback period of the proposed drying system is approximately 0.76?years.