Numerical simulation of the 3D simultaneous heat and mass transfer in a forced convection solar drying system integrated with thermal storage material

The demand for quality dried products necessitates cost effective and innovative drying techniques that will improve its market value. The slow drying rate, weather dependency, and moisture reabsorption have been identified as the major challenges of solar drying operation. To address these shortcomings, hybrid solar drying systems have been recommended for the drying of various agricultural materials and other porous products. Designing a better drying system to accommodate thermal storage materials requires detailed analysis, which could be achieved through numerical simulation. Therefore, the numerical simulation of heat and mass transfer in a forced convection solar drying system integrated with black coated firebrick sensible thermal storage materials (STSM) for the cocoa beans, locust beans, cereal grains, etc. was investigated under no load conditions. The equations governing the fluid flow for a three-dimensional (3D) solar drying system were solved using the Finite Volume Method (FVM) with the aid of ANSYS, the computational fluid dynamics (CFD) software to comprehend the dynamic and thermal behaviour of the airflow within the dryer. The experimental maximum temperature values of 96.9 and 77.3oC for the collector and drying chamber were in agreement with the simulated maximum collector and drying chamber temperatures (CT and DCT) of 116.9 and 80oC respectively. The designed solar drying system with the incorporated STSM showed the capacity of raising the temperature of the air within the drying chamber to 3-37oC above ambient temperature between 13:00 hr to 22:00 hr. The agreement of the simulated dryer model with the experimental one is an indication that the developed dryer is suitable for drying cocoa, locust beans, fish, cereal grains, and some other agricultural products within an acceptable period based on the previous studies and therefore, the drying system is recommended to avoid the shortcomings associated with traditional/open sun drying.