Dryers for drying products in post-harvest processing are technologies involving complex system of transient heat, mass and momentum transfer combine with material science. A detailed understanding of the behaviour of the processes to analyze the interactions between various components of the system cannot be gained by testing alone especially not within the time and economics constrains that the market allows. This paper proposes a simulation framework to the transient convection-diffusion model of the batch process in a rectangular passive greenhouse dryer. Computer aided engineering analysis (CAE) approach in a user friendly computer package ANSYS 14.0 involving computational fluid dynamics (CFD) simulation was employed to evaluate the performance of the dryer. Results obtained which compared with validations showed that the numerical procedure is able to predict the greenhouse dryer design parameters as well as the batch process parameters. The results of the simulations of temperature within the rectangular passive greenhouse dryer’s cavity were within and those of experimental studies yielded the range . These results represent accuracy of 85.77%. Hence, the numerical simulations predict with degree of accuracy the transient temperature distribution as well as the thermophysical properties of the drying medium in the multi-racks passive greenhouse dryer.