Performance analysis of a solar dryer integrated with the packed bed thermal energy storage (TES) system

Abstract

This study presents the energy and exergy-based performances of a solar dryer integrated with packed bed (TES) as thermal energy storage medium. As a sample application, drying kinetics of orange slices was determined. The aim of this study is to evaluate the thermal storage potential of the packed bed by focusing on energy consumption and exergy-sustainability indicators. Experiments were repeated twice a day (sunshine hours and off-sunshine hours). The results indicated that solar dryer integrated with packed bed reduced the moisture content of orange slices from 93.5% to 10.28% (at the first experiment) and 10.76% (at the second experiment), respectively. Total useful energy consumption for both the two status were detected as 89.892 MJ and 88.11 MJ, respectively. The exergy efficiency for the drying system during the sunshine hours ranged from 50.18 to 66.58%.The exergy efficiency of the drying process, in case of using the stored thermal energy, also changed between 54.71 and 68.37%. Moreover, a mathematical model was developed to predict the change of the moisture ratio of orange slices during time. According to the results of the model, Modified Henderson and Pabis Model presented the optimum parameters for determining the drying kinetics of orange slices.