Chaomuang, Nattawut

Preferred name

Chaomuang, Nattawut

Alternative Name

Chaomuang, N.

Main Affiliation

School of Engineering

nattawut.ch@kmitl.ac.th

Now showing 1 - 10 of 18

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Storage conditions, energy consumption, and food safety implications of domestic refrigerators in Bangkok
(2025-12-01)
Chaomuang, Nattawut
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Potisuwan, Cheeraphat
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Duret, Steven
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Derens-Bertheau, Evelyne
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Paviet-Salomon, Yvanne
Domestic refrigeration plays a critical role in food preservation and safety by maintaining optimal storage conditions for perishable items. This study investigated the temperature and humidity conditions, as well as the energy consumption, of domestic refrigerators in Bangkok. Data were collected through on-site investigations of 123 refrigerators using data loggers to record temperature, humidity, and electrical consumption over a five-day period. In addition, a predictive microbiological model was used to assess the potential for microbial growth under the investigated storage conditions, specifically of Listeria monocytogenes and lactic acid bacteria (LAB). Results indicated that although the overall mean temperatures of chilling compartments (5.0 ± 2.5 °C) were within the recommended range for domestic refrigeration, only about 30–40 % of individual refrigerators consistently maintained temperatures at or below 5 °C on the top and middle shelves throughout the five-day monitoring period, where fresh and ready-to-eat products are typically stored. Electrical consumption analysis revealed significant differences across refrigerator types; appliances with two doors and bottom freezers exhibited the highest annual electrical consumption, while single door refrigerators recorded the lowest. However, the specific energy consumption (SEC) did not differ significantly among refrigerator types. The microbial exposure assessment based on a test product highlighted that for over 50 % of refrigerators, L. monocytogenes load exceeds the regulation safety limits (> 102 CFU/g) within five days. These findings emphasize the need for improved temperature control, appliance design, and consumer education to ensure food safety and energy efficiency in domestic refrigeration.
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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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Performance Evaluation of a Wet Medium Made of Mangosteen Peels for a Direct Evaporative Cooling System
(2023-12-01)
Chaomuang, Nattawut
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Nuangjamnong, Thanut
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Rakmae, Samak
The present study aimed to investigate an alternative evaporative cooling pad material made from mangosteen peel (MP) waste. Mangosteen peels were used to fill a 150 mm thick mesh container with a packing density of 180 kg/m3. A wind tunnel was constructed and utilized to experimentally evaluate the cooling performance of this organic-waste-based pad under hot and humid conditions (31–34 °C and 55–70% RH). The performance parameters assessed included pressure drop, temperature drop, saturation effectiveness, cooling capacity, and coefficient of performance (COP). The influence of air velocity (0.7, 1.0, 1.4, and 1.8 m/s) on these parameters was also examined. The results revealed that the saturation effectiveness of the MP pad ranged from 53% to 77% within the considered air velocity range. The maximum temperature drop (4.6 °C), saturation effectiveness (77%), cooling capacity (0.6 kW), and COP (3.5) were achieved when the system operated at 1.4 m/s. A comparative study showed that, at this velocity, the MP pad provided performance nearly equivalent to that of the commercial cellulose paper pad, except for the pressure drop. This result affirms the potential of mangosteen peels as a suitable wet medium for evaporative cooling applications.
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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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Dynamic heat transfer modeling of a closed refrigerated display cabinet
(2019-10-01)
Chaomuang, Nattawut
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Laguerre, Onrawee
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Flick, Denis
This study proposes a simplified heat transfer model of a closed refrigerated display cabinet using a zonal approach. The dynamic model was developed and solved with a spectral method to predict the temperature fluctuations occurring with “on/off” compressor regulation. The equivalent load thickness in which the temperature fluctuations were of the same order as those at the load surface was estimated as a function of “on/off” compressor operating frequency. The air temperature fluctuations are dampened whenever the air exchanges heat with solid surfaces (e.g. walls, loads) and with the ambient air (e.g. through the doors). Despite exposure to large air temperature fluctuations (up to 5 °C), the load surface temperature showed only small fluctuations (ΔT<inf>l</inf> ≤ 0.5 °C). Good agreement was found between the predicted and the measured temperature fluctuations. The model can also be applied in order to predict air and load temperature increases during defrost operation.
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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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Experimental and numerical characterization of airflow in a closed refrigerated display cabinet using PIV and CFD techniques
(2020-03-01)
Chaomuang, Nattawut
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Flick, Denis
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Denis, Alain
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Laguerre, Onrawee
Air velocity measurements were carried out using the Particle Image Velocimetry (PIV) technique in a display cabinet under two configurations: closed and open doors. Two conditions (refrigeration system turned “on” and turned “off”) were studied in the closed configuration. The airflow pattern was almost the same for both conditions. The air curtain was quite stable. In the upper part of the cabinet, air recirculation occurred, and this phenomenon induces external air infiltration through the door gaps. The air curtain in the open configuration (refrigeration system turned “off”) was less stable than the closed configuration. Large unsteady eddies developed in the mixing layers, thereby promoting greater external air infiltration. A two-dimensional computational fluid dynamic (2D-CFD) model was developed and showed the ability to reproduce the main flow phenomena observed in the experiment. The trend of predicted product temperature profile was also in agreement with the experimental values, despite slight underestimation.
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Temperature Difference in Loading Area (Tarmac) during Handling of Air Freight Operations and Distance of Production Area Affects Quality of Fresh Mango Fruits (Mangifera indica L. ‘Nam Dok Mai Si Thong’)
(2022-11-01)
Srisawat, Kraisuwit
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Sirisomboon, Panmanas
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Pun, Umed Kumar
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Krusong, Warawut
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Rakmae, Samak
Mango (Mangifera indica L.) ‘Nam Dok Mai Si Thong’ is an important cultivar for export from Thailand. Export mainly takes place via air transport, but for about 2 h at the loading area (tarmac), unit loading devices (ULDs) are exposed to ambient environmental conditions. In this research, the effects of different temperature conditions at the loading area (tarmac) and the distance of the production area from the tarmac on the quality of fresh mango fruits were studied. The treatments included three temperature conditions for 2 h (simulated handling in tarmac)—constant temperature (20 °C), non-insulated or insulated and exposed to sun—and two distances of the tarmac from the production area—short distance (i.e., transport occurring 53 h after harvest) and long distance (i.e., transport occurring 70 h after harvest). The temperature variation in the boxes exposed to the sun was greater in the non-insulated than in the insulated boxes, but this effect was more pronounced in fruit from the short-distance production area (28.1 °C insulated and 36.9 °C non-insulated) than in fruit from the long-distance production area (34.2 °C insulated and 38 °C non-insulated). Insulation and short distance increased the shelf life, decreased weight loss, delayed the decrease in average firmness and rupture force, etc. The insulation of mango fruit boxes mitigates the deleterious effect of exposure to 2 h of direct sun by reducing the increase in temperature, thus improving the shelf life and quality of mango fruit.
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Experimental analysis of heat transfer and airflow in a closed refrigerated display cabinet
(2019-03-01)
Chaomuang, Nattawut
;
Flick, Denis
;
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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Experimental investigation of airflow and heat transfer by natural convection in an insulated box with a Phase Change Material using a Particle Image Velocimetry technique
(2023-01-01)
Leungtongkum, Tanathep
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Laguerre, Onrawee
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Flick, Denis
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Denis, Alain
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Duret, Steven
Airflow and heat transfer via natural convection in an insulated box with Phase Change Material (PCM) were experimentally investigated using Particle Image Velocimetry (PIV) and temperature measurements. The effects of PCM positions (side wall and lid) on flow pattern and temperature distribution were studied under empty and loaded conditions. Two loads were considered to study the obstacle effect and the influence of heat exchange with air. When PCM was either at the side wall or at the lid of the box, laminar flow was observed and the corresponding Rayleigh number was about 107. Upward flow was always observed near the side walls of the box. When PCM was on the side, downward flow occurred along the PCM; in the empty case, flow was almost 2D but became 3D when the load was added. When PCM was on the lid, the air cooled in contact with PCM, detached from it and flowed downwards. In the empty case, downward flow was unstable, and with the load, it followed preferential pathways. The type of load exerted little effect on flow patterns at thermal steady state. Thus, a simpler load (extruded polystyrene) can be used in the first approach. The maximum velocity was about 0.1 m s−1, so free convection cannot be neglected compared with conduction. Regarding temperature performance, PCM on the side and on the lid showed no substantial difference if gaps were left between the load and the walls or PCM.

Chaomuang, Nattawut

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