Experimental study on drying kinetics for Zingiber Officinale using solar tunnel dryer with thermal energy storage

Abstract

This research reports an experimental analysis performed using a forced convection solar tunnel dryer integrated with eco-friendly low-cost sensible heat storage material. The experimental setup consists of a single pass air heater and solar tunnel dryer for drying Zingiber Officinale (Ginger). The dryer unit was tested for a two-kilogram ginger load at 12.9165° N, 79.1325° E in the hot air temperature range of 33–74 °C. Performance of drying process for two novel configurations (with sensible heat storage and north wall reflection) and two modes (active and passive) were analyzed. The raw ginger samples initially had a moisture content of 80–82% (w.b.) and were reduced to 9–10% (w.b.) in two successive days. Sensible heat storage found to increase the average temperature of the dryer by 10 °C during the drying process. The results conclude that active drying mode with and without sensible heat storage has the fastest moisture removal rate than passive drying. Amidst the eleven drying models, the models of Midilli – Kucuk and Wang – Singh had best described the kinetics of the product drying. The overall efficiency of the dryer system and specific energy consumption of the ginger was 45% and 5.56 kW-h, respectively for passive mode. The SEM analysis carried out on different micron pore sizes of dried ginger attained uniform moisture removal with a homogeneous surface and a clear fibrous structure.