Design and simulation of a hybrid solar biomass dryer for coffee seeds in rural areas

Abstract

The application of solar drying, especially in agricultural areas, has been proven to be practically, economically, and environmentally friendly. However, the drying process is limited only in a sunny environment and often interrupted during cloudy or rainy days and also at night. A hybrid dryer with a thermal backup technique has been adopted to overcome the limitation of a solar dryer. The combination of the systems is expected to create 24 hours a day of the non-interrupted drying process. The study on the drying system was carried out by two analysis techniques; analytical and simulation. The conceptual design of the simulation model was based on analytical modelling of the drying process using solar or the backing up heat source. The work extension involved simulation of the developed hybrid dryer by employing Engineering Equation Solver (ESS) software under different operational modes. The coffee dryer was simulated by drying it under different modes, which were; solar alone and thermal backup alone. It was found that the fastest drying process was in the biomass drying mode.