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Enhancing supply chain efficiency for air transport of horticultural products by simplified heat and mass transfer modelling
(2026-08-01)
Jantapirak, Suveena
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Duret, Steven
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Laguerre, Onrawee
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Denis, Alain
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Paviet Salomon, Yvanne
Maintaining temperature and quality stability of fresh horticultural products during air transportation is challenging due to highly variable thermal environments and limited airflow inside Unit Load Device (ULD) containers. This study developed a simplified three-dimensional heat and mass transfer model to predict product temperature and moisture evolution within a ULD container under realistic operating conditions. Plaster mangoes were used to avoid the variability of the real product properties. Convective heat transfer and three-directional thermal resistances were integrated into an unsteady heat balance model while the model parameters were calibrated using Monte Carlo simulation. A complementary mass transfer model, considering the ULD container as a closed moisture domain, was implemented to estimate product mass loss. Model performance was evaluated using cooling experiments under controlled conditions and field measurements in a ULD shipment from Bangkok to Paris by air transport. Simulated air and product temperatures showed good agreement with experimental data, with RMSE values below 3.5 °C. The model successfully captured the pronounced thermal load on top-layer boxes during tarmac exposure and the faster cooling of bottom boxes through conduction with the bottom wall during flight. Predicted mass loss (1.0-1.1%) also aligned with field data (1.1-1.2%). The model provides a practical tool for assessing the effects of operational and environmental conditions on fruit quality during air transport.
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Evaporative cooling with a wet fabric blanket for non-refrigerated horticultural produce transport: An experimental study
(2024-12-01)
Chaomuang, Nattawut
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Laguerre, Onrawee
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Supapvanich, Suriyan
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Flick, Denis
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Duret, Steven
Due to the high cost of mechanical refrigeration, Evaporative Cooling (EC) can be an alternative technology for small farmers in developing countries, such as Thailand. This study aimed to experimentally investigate the performance of EC using a wet fabric blanket. A real-scale cargo chamber, commonly used in Thailand, was constructed, and equipped with axial fans to simulate airflow during transportation. Two pallets of test products (hollow plastic balls) were loaded into the cargo and covered with the wet blanket. During the experiment, the inlet air velocities varied from 0.8 m s−1 to 3.6 m s−1 while the constant climate conditions were maintained (29–30 °C and 70–73 %RH). The air and product temperatures and air relative humidity were measured every minute for 3 h using thermocouples and hygrometers, respectively. The proposed EC method allowed the air temperature to decrease by approximately 3–4 °C. When the inlet air velocity decreased, a lower temperature reduction was observed. Simplified heat and mass transfer models were developed to interpret the load temperature evolution from the inlet to the outlet positions at different air velocities. The comparison between the measured and calculated data revealed a maximum mean relative error of 1.2 %. The quality preservation performance was also evaluated based on lettuce mass loss. Lower mass loss was observed for the product stored inside the cargo chamber (<6 %) compared to those outside (8–10 %). This study suggests the potential use of a wet blanket as an EC cooling medium for a short-distance transport to enhance the cold chain performance in Thailand.
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Temperature control in a horticultural produce supply chain in Thailand and its influence on product quality
(2022-03-01)
Chaomuang, Nattawut
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Singphithak, Parinya
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Laguerre, Onrawee
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Suwapanich, Rachit
The present study was conducted in order to investigate the temperature conditions in the horticultural produce cold chain in Thailand, and fresh-cut baby corn was chosen for a case study. The field investigation together with in-person interviews were performed at 4 growers' premises and one packing house. The information collected provided details on current postharvest conditions at individual stages from the growers’ premises to an export distribution center. Temperature measurements were carried out to explore the time-temperature profiles throughout these stages. The results showed that the total duration of these stages was almost 32 h, and the temperature variations were between 6 and 33 °C. Precooling was delayed for at least 9 h, since baby corn cobs were primarily processed by dehusking and bulk packing. The baby corn was maintained at a temperature below 6.0 °C in a cold room for almost half of the total duration. The effect of the postharvest temperature conditions on the product quality evaluation was assessed by measuring various physiological quality attributes during storage. It was found that the marketability of the baby corn subjected to such postharvest temperature conditions remained possible with a salable period of up to two weeks. The result made it possible to identify the stages during which temperature control was inadequate, and recommendations were proposed to the stakeholder partner in order to modify the postharvest conditions in order to extend the product shelf life.
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A simplified heat transfer model of a closed refrigerated display cabinet
(2020-06-01)
Chaomuang, Nattawut
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Laguerre, Onrawee
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Flick, Denis
Installation of doors on open refrigerated display cabinets is one of the simple and effective methods to improve the cabinet performance because it can reduce the warm and humid air infiltration into the cabinets. However, the presence of doors can change airflow pattern, which in turn influences the heat transfer and product temperatures. It is, thus, necessary to understand these thermal phenomena. This study proposes a simplified heat transfer model developed based on a zonal approach to describe the evolution of air and product temperatures at different zones in the closed refrigerated display cabinet. For model validation, the predicted values were compared with measured air and load temperatures for three external air temperatures. Good agreement was found between the predicted and measured temperatures with the maximum difference of less than 0.5 °C for every studied position and the overall mean absolute error of 0.2 °C. The model was then used to predict the effect of the air infiltration through the door gaps on the performance of the closed display cabinet in both thermal and energy aspects. This developed model will be further used in the modeling of the cold chain, where several types of refrigeration equipment are used to keep products under low-temperature conditions from production to consumption. Through integration of quality and microbiological predictive models, this approach can be used as a numerical tool for an evaluation tool for consumer risk.
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Influence of operating conditions on the temperature performance of a closed refrigerated display cabinet
(2019-07-01)
Chaomuang, Nattawut
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Flick, Denis
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Denis, Alain
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Laguerre, Onrawee
An experimental study was performed in order to investigate the effects of operating conditions, including door opening frequency, ambient air temperature and product-occupied volume, on the air and product temperature distributions inside a closed refrigerated display cabinet. The product position in the cabinet is a determining factor of its temperature: a high temperature was observed at the front, particularly at the top of the cabinet, and a low temperature was observed at the back. Air infiltration due to door openings caused a product temperature increase at the front and a temperature decrease at the back. At a higher door opening frequency (more than 60 openings per hour per door), the product temperature at the level of the front middle shelf was the most affected. Both the ambient temperature and occupied volume also affected product temperature variations in the closed display cabinet. In comparison to an open display cabinet, a closed display cabinet achieves lower product temperature and better temperature homogeneity, even with a high door-opening frequency. These findings indicate that the use of closed refrigerated display cabinets should be advocated in order to achieve better food preservation.
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Experimental analysis of heat transfer and airflow in a closed refrigerated display cabinet
(2019-03-01)
Chaomuang, Nattawut
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Flick, Denis
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Denis, Alain
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Laguerre, Onrawee
This study presents the experimental investigations on heat transfer and airflow in a closed refrigerated display cabinet. Air and product temperatures and air velocity were measured with thermocouples and a hot-wire anemometer, respectively. Temperature variation in the cabinet depends on the positions. The front areas contributed to higher temperature, whereas the rear areas were at a lower temperature. Benefits of doors were also examined by comparing the results of air and product temperatures with the case without doors. The cabinet with doors provided less temperature heterogeneity (ΔT<inf>max</inf>= 2.1 °C) compared to the case without door (ΔT<inf>max</inf>= 4.9 °C). The maximum air velocity in the air curtain of 0.6 m s−1 was observed at the discharge grille. The horizontal air velocity from the perforated plate was low (<0.2 m s−1) for all shelves. The loading percentage in the cabinet did not significantly affect the airflow rate through the perforated plate.
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A simplified heat transfer model of a closed refrigerated display cabinet
(2019-01-01)
Chaomuang, Nattawut
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Laguerre, Onrawee
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Flick, Denis
A simplified heat transfer model for a closed refrigerated display cabinet was developed based on a zonal approach. The developed model allows the prediction of time-averaged air and load temperatures at various positions in the display cabinet. These predicted values were compared with measured air and load temperatures. Good agreement was found between them with the maximum difference of 0.5°C for every studied position and the overall mean absolute error of 0.2°C. Air and load temperatures vary with positions. High temperature was observed at the front (highest value at the front top) and low at the back (lowest value at the back bottom). Based on the simulation, the cabinet thermal performance can be enhanced by minimizing the size of door gaps.

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