Natural convective greenhouse vermicelli drying: Thermo-environ-econo-kinetic analyses

This article presents the performance of a low-cost, simple and sustainable natural convection greenhouse dryer (NCGHD) for vermicelli drying. Vermicelli samples of diameter (0) 1.25, 2 and 3 mm have been dried until no moisture evaporation was observed. The values of convective and evaporative heat transfer coefficients for 03 mm vermicelli samples were observed to be the highest (1.37 and 210.83 W/m2 degrees C) followed by 02 mm (1.02 and 87.93 W/m2 degrees C) and 01.25 mm (0.55 and 43.50 W/m2 degrees C) samples. The overall greenhouse and energy effi-ciencies for 03 mm vermicelli samples were also found highest (9.02 and 15.87 %) as compared to 01.25 and 2 mm vermicelli samples. The increasing diameter of the vermicelli samples resulted in reduced payback period and energy payback time; and increased carbon credit earned. Midilli-Kucuk model showed the highest congruence with the data of experimental moisture ratio for vermicelli drying. Effective moisture diffusivity increased from 2.09x10- 11 to 1.06x10- 10 m2/s with the increasing vermicelli diameter from 01.25 to 3 mm. The experimental uncertainty varied from 1.138 to 1.199 % for given vermicelli samples. This study would be insightful to researchers in designing the most sustainable vermicelli drying system with greater simplicity and performance; and lowest financial and energy requirements.