Analysis of Energy Consumption in a Combined Microwave–hot Air Spouted Bed Drying of Biomaterial: Coffee Beans

In this study, an energy model based on the first law of thermodynamics is developed to evaluated energy efficiency and specific energy consumption. The influences of hot air temperature and initial weight of coffee beans on energy consumption are considered. Furthermore, a comparison between combined microwave–hot air spouted bed drying and hot air spouted bed drying methods on energy consumption is also investigated in detail. The results show that energy efficiency as well as energy consumption depends on hot air temperature, initial weight of coffee bean, and typical drying methods (combined microwave–hot air spouted bed and hot air spouted bed). The optimum drying condition is also achieved in this study.