Simulation of in-line versus staggered arrays of vented pallet boxes for assessing cooling performance of orange in cool storage

The cooling performance of fruits and vegetables including transient heat removal, temperature homogeneity and moisture loss inside the cool storages is affected by pallet boxes arrangement. In this paper, the effect of two different types of vented pallet boxes arrangement including in-line and staggered on cooling performance were compared while longitudinal gaps between the pallet boxes and cooling airflow varied at three commonly applied levels. Validated computational fluid dynamics (CFD) models of airflow, heat and mass transfer were applied as an alternative for the experiments. Results showed that staggered array increased the surface heat transfer coefficient at the pallet boxes wall from 18% to 53%, which caused 28% to 38% reduction in ¾ cooling time compared to in-line. The most effectiveness of staggered array on heat transfer coefficient occurred for 0.25 m longitudinal gap between the pallet boxes. Staggered array did not improve temperature homogeneity and moisture loss. Results also showed that, an increment of longitudinal gaps from 0.1 to 0.25 m caused 10% reduction in ¾ cooling time. Increasing more than 0.25 m, did not showed reasonable improvement in cooling performance.