The role of horticultural carton vent hole design on cooling efficiency and compression strength: A multi-parameter approach

• A multi-parameter approach was applied to evaluate packaging performance.
• Cooling performance was simulated using CFD models.
• Carton strength was negatively related to vent hole area.
• Multivent vent hole design used 58% less FAC energy than standard design.
• Proposed new vent configurations offered better ventilation alignment.

Forced-air cooling (FAC) is used to rapidly remove the field heat of horticultural produce to better preserve quality. Cartons are ventilated to promote uniform cooling of the packed produce and to minimise energy used by precooler fans. The resulting cooling efficiency is influenced by the area and configuration of carton vent holes. However, placing vent holes also reduces the carton compression strength, which requires reinforcement using additional fibreboard, thereby increasing carton manufacturing costs. This study, therefore, applied a multi-parameter evaluation approach to assess four carton designs, each for three vent hole areas and three corrugated fibreboard grades. Computational fluid dynamics (CFD) was used to evaluate airflow resistance, cooling rate, uniformity and package related energy consumption. Experiments were used to quantify box compression strength. Results of mechanical strength evaluation showed a negative linear relationship between carton strength and vent hole area. The effect of vent hole configuration on compression strength was dependent on the corrugated fibreboard grade. For cartons packed using trays, the Multivent vent hole design used 58% less FAC energy and also significantly improved cooling uniformity compared to the Standard vent design. The significant improvement in FAC energy efficiency, therefore, enables the Multivent to match or improve the compression strength and FAC energy efficiency of the Standard vent design, by using a considerably smaller ventilation area. This study thus demonstrates the importance of incorporating a multi-parameter approach in developing improved packaging with optimised vent hole designs.

Convective heat transfer coefficient across fruit surface at 1 L kg−1 s−1 for each type of carton designFigure optionsDownload as PowerPoint slide