Modeling and Simulation of Deep-Bed Solar Greenhouse Drying of Chamomile Flowers

Abstract

An effective and innovative strategy for modeling and simulation of deep-bed solar greenhouse drying of biomaterials using TRNSYS software is presented in this article. Deep-bed solar greenhouse drying principles were written in Compaq Visual FORTRAN programming language through the combination of thin-layer drying principles and equilibrium drying model and the created new component was added to the software's library. Experimental data for deep-bed solar greenhouse drying of chamomile obtained at different specific loads of 15, 30, 45, and 60 kg/m2 were used for model verification. In the newly developed component, thin-layer drying principles with the assumption that each bed composed of a series of thin layers was employed to simulate the drying process of chamomile. The moisture content and temperature profiles of the material as well as the temperature and humidity ratio profiles of drying air within bulk were computed using a rarely employed equilibrium model. There was good agreement between simulation results and experimental moisture content for deep-bed solar greenhouse drying of chamomile with root normalized mean square error lower than 9.3%. Findings of this study confirmed that TRNSYS is a powerful tool for optimization of the operation and design of solar dryers. The advantage of using the proposed strategy is that solar greenhouse drying systems can be effectively designed and developed for a wide range of biomaterials under different climate conditions without need for demonstration projects.