Designing Active Mode Double Air Pass Solar Tunnel Dryer and Analysis of Factors Affecting Energy and Exergy Outcome Performance of the Drying System

Abstract

This study aims to design and performance evaluation of an active mode solar tunnel dryer with a double air pass for drying charcoal dust briquette. The influence of solar tunnel dryer shape, heat flux input, and air velocity on outlet air temperature, energy, and exergy parameters was studied by developing a mathematical
model. The numerical solution was programmed in PYTHON software. Three shapes of solar tunnel dryers are designed with similar collector surface areas: Quonset, triangular and rectangular. The outlet temperature, thermal efficiency, and exergy efficiency vary from to , to , and to , respectively, for heat flux input variation between and at and semi-circular shape dryer. The effect of the solar tunnel dryer shape was performed. The higher outlet temperature, energy, and
exergy value was found for a semi-circular shape, followed by a triangular shape. The most negligible value was found for a rectangular shape. The analysis of air velocity variation reveals that the value of energy efficiency and exergy efficiency increases, and the value of outlet temperature decreases as air velocity increases. Therefore, the energy and exergy performance of active mode double air pass solar tunnel dryer is affected by solar tunnel dryer shape, input heat flux, and air stream velocity.