Analysis of ginger drying inside a natural convection indirect solar dryer: An experimental study

Abstract

In this paper, a natural convection indirect solar cabinet dryer has been fabricated to study the drying behaviour of ginger rhizomes in terms of its convective heat transfer coefficient and moisture removing rate (% db). Various experiments were conducted during the months of March and April 2014 at Guru Jambheshwar University of Science and Technology, Hisar (29o 5’5’’N, 75o 45’55’’E), India. Experimental data obtained were used to evaluate the Nusselt number constants using linear regression method. Considering these constants, the average value of convective heat transfer coefficient was obtained and observed to decrease with increase in mass of ginger samples and progression of drying days with variation from 0.59 to 5.42 W/m2 ˚C for different mass of ginger samples. The moisture removing rate was reported to increase with increase in mass of ginger samples and decreases significantly with the progression of drying days. The average collector efficiency was also observed to vary from 14.97 to 16.14% under increasing and decreasing trends of solar radiations from morning to noon and noon to evening respectively. Modified page model was reported best for describing the drying behaviour of different mass of ginger samples. The experimental error in terms of percent uncertainty ranged from 29.19 to 46.25%.