Abstract

The main goal of this work is to evaluate the thermal performance of a medicinal herb dryer assisted by two-phase thermosyphon technology. A medicinal herb dryer, assisted by thermosyphons in tree configuration, was developed at the LABTUCAL (Heat Pipe Laboratory) at UFSC (Federal University of Santa Catarina, Brazil). In this new dryer concept, the air heating occurs directly inside of the drying chamber, resulting in a highly homogeneous temperature distribution inside the drying chamber. A simplified mathematical model employing the analogy between thermal and electrical circuits was applied to represent the physical behavior of the tree thermosyphons. The influence of the mixer speed on the total energy consumption per unit of water mass evaporated was analyzed, as well as the drying air temperature and humidity distributions. The results show that the developed dryer is able to guarantee a high homogeneity of temperature and relative humidity of the drying air inside the chamber. As a result, the dried herb has superior quality when compared with other commercially available dryers.