Importance of integrated CFD and product quality modeling of solar dryers for fruits and vegetables: A review

Abstract Improper handling of fruits and vegetables causes a significant postharvest loss. Among the postharvest preservation mechanisms, solar dryers are reported as sustainable and suitable preservation systems for fruit and vegetable products. This paper summarizes the recent advances, opportunities, and challenges in solar drying of fruit and vegetable products. Besides, the review discusses the commonly used mathematical models for the evaluation, design, and optimization of solar dryers. The review discusses the factors that affect the performance of solar drying systems concerning drying time, drying rate, and product quality attributes. Short drying time, uniform drying air velocity, temperature, and product moisture distribution in the drying chamber are the critical parameters that are required for an efficient operation of a solar dryer. There is a good prospect in the application of mathematical modeling techniques such as computational fluid dynamics (CFD) in identifying the optimum solar drying conditions and dryer design that can maintain the required quality of the product. CFD has been used extensively in studying the airflow, heat, and mass transfer processes for optimizing the design and operation of different drying systems, similarly different quality models have been applied to evaluate the quality of dried products. However, most CFD studies did not include the quality aspect for dryer performance evaluation or optimization studies. To get the best result, CFD based performance evaluation or optimization studies of the solar dryers should have the capacity to predict the product quality in addition to the airflow, heat, and moisture transfer characteristics.