Authors: Hahn, F., G. Herna´ Ndez, J. Herna´ Ndez, C. Pe´Rez And J.M. Vargas.
Download file: https://library.csbe-scgab.ca/docs/journal/53/C1136.pdf
Published in: CBE Journal » CBE Journal Volume 53 (2011)
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Description: In solar drying, end-product quality is often adversely affected by open-air exposure to pollution leading tolower economic profits for producers. A polyethylene plastic covered tunnel was constructed for drying roselle calyxes. Threedifferent drying techniques were evaluated and compared to search for optimum drying conditions. Calyx color images, waterloss and calyx crispness of dried products were evaluated along the tunnel. Roselle drying using fan control took 27 hours, optimizing energy consumption and increasing air temperaturewithin the tunnel. An air recirculating system using silica gel for removing air moisture decreased the drying time to 8 hours andobtained crisper calyxes. Moisture retained by the silica gel desiccant material was automatically removed by heat regeneration.Calyxes were dried in 4.5 hours at 708C with a hybrid solar biogas system. One kg of biogas was burned per kg of driedproduct.
Keywords: biogas, silica gel desiccant wheel, roselle calyx, solar tunnel, crispness ratio
Citation: Hahn, F., G. Herna´ ndez, J. Herna´ ndez, C. Pérez and J.M. Vargas. 2011. Optimization of roselle drying time and drying quality.Canadian Biosystems Engineering/Le génie des biosystèmes au Canada. 53: 3.1-3.8
Pages 3.1 - 3.8