Numerical Optimization of Thermoelectric Heat Pump Assisted Drying System

Abstract

One of the methods for food preservation involves utilizing the heat from solar radiation to remove moisture, aptly known as solar drying. Different approaches in enhancing solar dryer efficiency have been made throughout the years, involving circulation refinements, mechanism improvements, and insulation enhancements. Thermoelectric heat pumps (TEHP) leverage the Peltier effect to generate temperature difference that can be integrated with solar dryer system. However, the information on design and parameters for integration is scarce and underexplored. In this work, TEHP-assisted solar drying system was designed and the ideal parameters for efficient drying rate were determined by optimizing fan position and airflow rate. The system’s performance was gauged through moisture content reduction of drying loads (ginger). CFD numerical optimization was performed at the airflow rate between 0.003 - 0.012 m³/s, at three different fan locations. Results showed that lower airflow rate increases the accumulated heat inside the chamber, resulting in higher moisture content removal within the load, thus increasing drying rate. Even though the higher airflow showed greater reduction in H₂O mass, reduction of drying chamber temperature was also observed, resulting in reduced effectiveness in moisture removal. The ideal fan position and airflow rate were determined to be at the system inlet (Fan 1) and 0.012 m³/s, respectively. The results from this work show the importance of fan position and airflow rate on a TEHP-assisted solar dryer towards its the drying rate to achieve a balance between energy consumption and effective drying.