DESIGN OF SUSTAINABLE DRYER WITH EXPERIMENTAL AND NUMERICAL APPROACH

Abstract

The capstone project focuses on designing a small-scale sustainable drying unit to study the drying process of wet materials under relatively dry air applicable for the subcontinental climate of the Astana region. This project explores the design, performance, and sustainable drying processes of wet materials, with a focus on waste coffee grounds (SCG), silica gel, and grapes under forced convection and a heater. Drying is an important process both in the waste management and food preservation industry, particularly in regions with colder weather conditions. This project simulates primarily solar greenhouse drying systems (SGHDs) typically used in warm climates and proposes a modified solar drying unit with integrated heating for colder environments. Experimental analysis was conducted in a small-scale 30 cm by 30 cm dryer. In addition, computational fluid dynamics (CFD) simulations were performed using COMSOL Multiphysics by modeling mass and heat transfer, revealing airflow dynamics and temperature distribution within the drying systems. Results demonstrated that forced convection along with a bottom heater showed the highest moisture removal rate for all tested materials, closely aligning with simulated outcomes, with an average discrepancy up to 15%. This study contributes to the development of innovative, sustainable drying technologies that reduce energy consumption, mitigate greenhouse gas (GHG) emissions, and improve operational efficiency in diverse climatic conditions. The results provide possibilities for scaling up solar drying systems in various industries such as waste management and agricultural applications, by promoting circular economy initiatives.