Design and performance evaluation of an evacuated tube solar dryer for drying garlic clove

The design and development of an evacuated tube collector-based solar dryer with heat pipe for drying of garlic clove were carried out in the present work. For the experimental performance evaluation, garlic cloves (10 kg) were dried from 69% to 8% moisture content (wb). The thermal performance of the evacuated tube solar dryer (ETSD) was tested on no-load and full load conditions at different air flow velocities (1, 2, and 3 m/s). The highest temperature of 86.7 degrees C, at no load condition, was obtained in the drying chamber at 2 m/s air flow velocity with the maximum solar radiation of 1204 W/m(2) while the maximum peak sun hour was 6.27. The maximum drying rate, solar collector efficiency, and dryer efficiency were found to be 1.56 kg H2O/kg dry solid/h, 45.86%, and 56% respectively at 2 m/s air flow velocity. The highest average exergy efficiency of 56.59% was found at 2 m/s, and the average lowest exergy loss of 4.74 W was found at 1 m/s. ETSD performed efficiently at 2 m/s air velocity and was capable to dry the garlic clove within 8 h. The payback period of the developed ESTD was found to be 1.3 years. (c) 2020 Elsevier Ltd. All rights reserved.