Specific Heat and Thermal Conductivity of Berberis Fruit (Berberis vulgaris)

Berberis fruit was known as a medicinal and ornamental plant in the world. It is used in medicine to cure the liver, neck and stomach cancer, blood purification and mouth scent. In order to design of equipments and facilities for the drying, preservation and processing of berberis, it is necessary to know about the specific heat and thermal conductivity. Therefore, the objectives of this study were to determine the specific heat and thermal conductivity of berberis as well as to develop mathematical models for estimation of them. The method of mixtures and hot wire as a heating source was used for measuring the specific heat and thermal conductivity of berberis fruit, respectively. The selected variables to simulate variations of berberis thermal properties were moisture content and temperature. The measurements were done at 50, 60 and 70°C temperature levels and 19.3%, 38.5%, 55.4% and 74.3% (w.b) moisture content levels. The results show that the specific heat and thermal conductivity of berberis increased linearly from 1.9653 to 3.2811 kJ/kg°C and 0.1324 to 0.4898 W/m°C, respectively with increase in the experimental range of the variables. However, the effect of moisture content on increasing the specific heat and thermal conductivity is more than that of temperature. Regression equations were established which could be used to reasonably estimate the values of the specific heat and thermal conductivity as a function of specified moisture content and temperature.