Effect of Temperature and Moisture Content on Thermal Conductivity of Green Teas

The thermal conductivity of green teas has been used as engineering parameter in the design of processes and machines for drying, storing and aeration. The thermal conductivity of green teas was determined and its changes with moisture content, bulk density investigated. The thermal conductivity values of green teas increased from 0.036 to 0.438 W m(-1) K-1 and from 0.041 to 0.568 W m(-1) K-1 for low and high (loose and dense) bulk densities, respectively, as the moisture content increased from 5.3 to 78.7% dry basis. The change of the thermal conductivity of green teas with temperatures at different bulk densities shows that it increased from 0.035 to 0.045 and 0.042 to 0.053 W m(-1) K-1, respectively, as the temperatures and bulk density increased. The thermal conductivity values obtained with the high bulk density was higher than those obtained with the low bulk density for green teas.