Using a Forced Convection Solar Drier for Bamboo Shoots
Abstract
Three different drying methods, a new designed forced convection solar drier, typical cabinet type natural convection solar drier and traditional open-sun drying were used for draying of bamboo shoots in central Vietnam. During drying the operational parameters such as drying temperature, relative humidity, air velocity, insolation and water evaporation have been recorded hourly. The mean drying temperatures and relative humidity in the drying chamber were 55.2°C, 23.7%; 47.5°C, 37,6%; 36.2°C, 47.8% in forced, natural convection solar driers and open-sun drying, respectively. The mean global radiation during all experimental runs was 670 W/m2. The result also shows that fastest drying process was occurred in forced convection solar drier where the fallingrate period was achieved after 7 hours, in change to open-sun drying where it took 16 hours. The dryer efficiencies were 22%, 15.8% and 9.7%, for forced, natural convection solar driers and opensun drying, respectively. It may be concluded that a new designed forced convection solar dryer is suitable for drying crops such as bamboo shoots and in all cases, the use of this drier led to considerable reduction in drying time in comparison to traditional open-sun drying.