Exploring ambient loading of citrus fruit into reefer containers for cooling during marine transport using computational fluid dynamics

Abstract

Defraeye T., Cronjé P., Verboven P., Opara U.L., , Exploring ambient loading of citrus fruit into reefer containers for cooling during marine transport using computational fluid dynamics, Postharvest Biology and Technology 108, 91-101. AbstractA promising cold-chain protocol is explored as an alternative to the commonly-used forced-air pre-cooling (FAC) of citrus fruit prior to shipping: ambient loading of fruit in reefer containers for cooling during long-haul marine transport. Despite the multiple logistical and economical savings it provides, the potential of "ambient loading" of fruit in reefer containers has been left largely unexplored. The present study targets this aspect, but also cooling by vertical airflow in general. Computational fluid dynamics (CFD) is used to identify differences in cooling rate and uniformity between individual boxes at different heights on a pallet and between individual fruit within a single box. Simulations show that low airflow rates, typical for refrigerated containers, do not only induce slower fruit cooling, compared to FAC airflow rates, but also the cooling heterogeneity between different layers of boxes (in height) and between individual fruit in a single box is larger. In addition, the presence of gaps between pallets invokes airflow short-circuiting, leading to highly reduced fruit cooling rates. Finally, strategies for future improvement of the ambient loading protocol are proposed, which in the first place should target faster and more uniform cooling. Keywordscomputational fluid dynamics; package design; cold chain; airflow short-circuits; vent holes; convective transfer Defraeye T., Cronjé P., Verboven P., Opara U.L., , Exploring ambient loading of citrus fruit into reefer containers for cooling during marine transport using computational fluid dynamics, Postharvest Biology and Technology 108, 91-101.http://dx

Time–Temperature Management Along the Food Cold Chain: A Review of Recent Developments

“…During the past decade, however, a few studies were carried out to explore the potential of ambient loading into reefers, for cooling during long‐haul sea transportation, as an alternative to forced‐air precooling of produce before it is loaded into the reefer. Defraeye and others (, ) explored the potential of this cold chain protocol for the ambient loading of citrus fruit, while Jedermann and others (, ) explored it for the banana chain. Ambient loading reduces the time and cost required to handle and precool the pallets at precooling facilities.…”

“…It can also reduce postharvest losses when applied immediately after palletization, since the cold chain starts earlier than when precooling occurs at the harbor, as transport to those facilities is often unrefrigerated. However, CFD simulations (Defraeye and others ) showed that the fruit cooling rate with ambient loading into reefers is slower in comparison with forced‐air precooling. Also, the cooling heterogeneity between different layers of boxes (in height) and between individual fruits in a single box is larger for ambient loading.…”

“…Models developed to map the temperature inside pallets can be separated into 2 types: physics‐based and data‐based. Physics‐based models describe momentum, heat, and mass transfer from 1st principles and have been successfully applied to map the temperature inside pallets during precooling (Ferrua and Singh , , ), transportation (Defraeye and others ; Han and others ), storage inside cold rooms (Hoang and others ; Nahor and others ), display at retail (Gaspar and others ), and storage inside domestic refrigerators (Laguerre and others ; Zhang and Lian ), among others. An increasing number of physics‐based models describing the different steps of the cold chain have been developed over the last decade, in large part because improved computational fluid dynamics (CFD) software has facilitated the numerical implementation of those models’ systems of partial differential equations.…”

Advance in Citrus Postharvest Management: Diseases, Cold Storage and Quality Evaluation

“…CFD is a method that using numerical, physical analysis and computational software solves and analyses problems related to fluid flows (air mixtures and liquids). Recently, Defraeye et al [59] suggested an innovative and promising cold-chain protocol alternative to the commonly used forcedair pre-cooling (FAC) of citrus fruit prior to shipping. The theoretical approach, by means of computational fluid dynamics (CFD), explored ambient (warm) loading of citrus fruit into refrigerated containers (reefer) for cooling by vertical airflow during marine transport.…”

New techniques and methods for cold chain monitoring and tracking in perishable products

“…Precooling and storage are very important part of the cold chain (Kumar et al, 2008;Norton et al, 2013), nonetheless, not too much attention is paid in the transport (James et al, 2006), if it is taken into account that the fresh produce suffer transport distances above several thousand kilometers (Jedermann et al, 2011a;Jedermann et al, 2011b). There is room for improvement and optimization in new protocols during the transportation (Defraeye et al, 2015b).…”