• Journal of Biosystems Engineering
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• v.25 no.4
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• pp.279-286
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• 2000

Most of the domestic cold storage rooms are inefficient for agricultural products because of temperature gradients inside the storage rooms. Temperature gradients are developed mainly by improper airflow pattern inside the storage room, which is a main cause of the spoilage of the agricultural products. There proper airflow pattern is essential to minimize these temperature gradients and the spoilage. The performance and characteristics of a cold storage room were determined as a function of airflow pattern and temperature distribution in forced circulation cold storage room. A commercial CFD(computational fluid dynamics) code was used to simulate 3-D airflow in the cold storage room. Solving the flow equations for the storage room, a standard k-$\varepsilon$ turbulent model was implemented to calculate steady state turbulent velocity distribution. The CFD prediction results were compared with temperature measurements inside the cold storage room. In case of pallet storage, Temperature gradients inside pallet storage was reduced because the contact area of cold air expanded through an alley of airflow in storage. But is case of bulk storage, the last temperature of storage considerably rose more than the initial temperature of storage. The reason was that bulk storage didn't include any alley of airflow in storage.

• Journal of Biosystems Engineering
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• v.25 no.2
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• pp.107-114
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• 2000

Low temperature storage method is to increase the value of agricultural products by reducing quality loss and regulate consignment time by controlling respiration rates of agricultural products. Respiration rate of agricultural products depends on several factors such as temperature, moisture, gas composition and a microbe inside the storage room. Temperature is the most important factor among these, which affects respiration rate and causes low or high temperature damage. Fuzzy logic was used to control the temperature of a storage room ,which uses information of uncertain facts and mathematical model for room temperature control . Room temperature was controlled better by using fuzzy logic control method rather than on-off control method. Refrigerant flow rates and temperature deviations were measured for on-off system using TEV(temperature expansion valve) and for fuzzy system using EEV(Electrical Expansion Valve) . Temperature of the Storage room was lowered faster by using fuzzy system than on -off system. Temperature deviation was -0.6~+0.9$^{\circ}C$ for on-off system and $\pm$0.2$^{\circ}C$ for fuzzy system developed. Temperature deviation and variation of temperature deviation were used as inout parameters for fuzzy system. The most suitable input and output value were found by experiment. Cooling rate of the storage room decreased while temperature deviation increased for the sampling time of 20 sec.

• Korean Journal of Veterinary Service
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• v.28 no.3
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• pp.225-234
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• 2005

Egg has been considered as one of the most important food sources in both nutritionally and economically. However, because the hazards of egg flow chains' complexity from producers to consumers and the insufficiency of cold chain systems in Korea are still remained, preventive measures for egg safety should be established. This experiment was carried out to investigate the changes of egg qualify during storage in order to find out the proper storage condition and eggshell treatment. Eggs were stored at cold condition $(5^{\circ}C,\;relative\;humidity;\;RH:\;65\pm3\%)$ and room Condition $(1st: Sep\; 6\~Nov\; 15,\;2001,\; 10\~30^{\circ}C,\;RH\;41\~86\%,\;2nd;\; Dec\;13,\;2001\~Feb\;21,\;2002,\;4\~23^{\circ}C,\;RH\;36\~89\%)$ after eggshell treatment (unwashed, washed and coated egg) during'10 weeks and examined weight loss and interior quality periodically. Weight loss was in decreasing order room washed > room unwashed > cold washed > cold unwashed > room coated > cold coated egg. And, Haugh unit was decreasing order room washed > room unwashed > room coated > cold washed > cold unwashed > cold coated egg. Our findings show that both coated eggs and refrigeration reduces the rate of decline in Haugh units and egg weight. And, washed eggs had lower average Haugh units and a higher weight loss than any of the eggshell treatment in both storage conditions. Conclusively, for washing eggshell, 150 ppm of sodium hypochlorite, regular exchange and temperature control of water should be consistent and also eggs should be dried immediately after washing. Also, national guidelines for temperature and moisture of storage places, transportation and expiration data should be established to keep quality and weight loss of eggs. Storage temperature that is a critical factor in the quality and safety of eggs should be kept under 12'c and labelling of expiration date should be obligatory.

• Agricultural and Biosystems Engineering
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• v.3 no.2
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• pp.65-72
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• 2002

Temperature is the most influential environment parameter which affects the quality change of agricultural products in cold storage. Therefore, it is essential to keep the uniform temperature distribution in the storage room. This study was performed to analyze the air movement and temperature distribution in the forced recirculating cold storage facility and to simulate optimum storage method of green groceries using 3-D CFD(three dimensional computational fluid dynamics) computer simulation which applied the standard $textsc{k}$-$\varepsilon$ turbulence model and FVM(finite volume method). The simulation was validated by the experimental results for onion storage and the simulation model was used to simulate the temperature and velocity distribution in the storage room with reference to the change of storage method such as location of storage, no stores, bulk storage, and pallet storage. In case of no stores, internal airflow was circulated without stagnation and consequently air movement and temperature distribution were uniform. In case of bulk storage, air movement was stagnated so much and temperature distribution of onion was not uniform. Furthermore, the inner temperature of onion roses more than the initial temperature of storage. In case of pallet storage, air movement and temperature distribution of onion were so uniform that the danger of quality change was decreased.

• Food Science and Preservation
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• v.31 no.1
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• pp.33-45
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• 2024

Three spring potato varieties (Atlantic, Chubaek, and Superior) were cultivated for 80, 90, and 100 days and compared in terms of their total and marketable yields and specific gravities. Subsequently, changes in the quality parameters (weight loss, sprouting rate, disease incidence, dry weight, and specific gravity) of potatoes cultivated for 100 days were monitored during two-month storage in improved and semi-underground warehouses at 4℃ and room temterature. The productivities of Atlantic, Superior, and Chubaek were maximized at cultivation periods of 100, 100, and >90 days, respectively. In all cases, cold storage resulted in <5.3% weight loss and no marketability loss. However, two-month room temperature storage resulted in pronounced marketability loss due to weight loss (6.2, 7.3% and 10.9% for Atlantic, Superior, and Chubaek, respectively) and sprouting (in ~13%, >75%, and 99% of Atlantic, Superior, and Chubaek tubers, respectively). The marketability of Atlantic, Superior, and Chubaek during cold storage was maintained for >2, ~2, and <2 months, respectively. All varieties were characterized by rapid sprouting, low dry weight and specific gravity, and rapid marketability loss during storage.

• Korean Journal of Plant Resources
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• v.25 no.5
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• pp.591-595
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• 2012

This study was conducted to investigate the possibility of changes in onion (cv. 'Turbo' and 'Changnyongdaego') bulb quality during storage at room and cold temperature. Increased weight loss was found in the onion bulb stored at both cold and room temperature conditions. 4% weight loss was found in bulbs stored at room temperature and 2% at cold storage as compared to fresh cultivated onion bulb; after three months. Initially, there was no significant difference in the firmness of bulbs between cultivars and storage conditions. Hunter a value of bulb stored at room temperature was higher than the value of bulb stored at cold temperature. 27% and 7.9% decay was found after three months in 'Changnyongdaego' and 'Turbo' cultivars stored under room temperature condition respectively. In contrast, only 2% decay was noticed in both cultivars stored at cold storage condition. Hunter L value of onion bulb gradually decreased in both room and cold temperature storage conditions. In conclusion, quality of onion bulb can be maintained until three months. For long term storage and quality maintenance, under room temperature conditions a resistance cultivar should be selected.

• Journal of Pharmacopuncture
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• v.6 no.2
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• pp.105-111
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• 2003

Objective : The purpose of this study was to investigate the stability of bee venom according to the keeping method and period. Method : The author observed microbial contamination of bee venom in nutrient agar, broth, YPD agar and YPD media and antibacterial activity for S. aureus, E. coli manufactured 12, 6 and 3 months ago as the two type of room temperature and $4^{\circ}C$ cold storage. Results : 1. 1:3,000 and 1:4,000 diluted bee venom solution did not show microbial contamination both room temperature and cold storage within twelve months. 2. There was antibacterial activity of diluted bee venom for S. aureus in cold storage within twelve months and there was no antibacterial activity of diluted bee venom for S. aureus in twelve months, room temperature storage. 3. We could not observe the zone of inhibition around paper disc of all for E.coli. in 1:3,000, 1:30,000 and 1:3,000,000 diluted bee venom solution, respectively. According to results, we expect that diluted bee venom solution is stable both cold and room temperature storage within twelve months.

• Korean Journal of Plant Resources
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• v.11 no.2
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• pp.136-141
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• 1998

To give some information on the harvest and storage of Chinese yam (Dioscorea opposita), the experiment was done to examine the effect of its harvesting date and storage method on tuber weight, tuberrelated characters during the storageor at the end of storage. The yam tubers harvested 4 times at 20 days interval from Oct. 15 were stored with different storage methods(pit, room and cold temperature) and on Mar.15. all the characters were measured. Fresh weight of the tuber harvestedafter Nov. 5 and stored were greater than that done on Oct. 15 while dry tuber weight did not have any difference between the harvesting dates. The fresh weigth done directly from the field on Mar. 15 was higher compared to the other harvesting dates owing to its higher moisture content. The rate of sound tuber stored at room or cold temperature condition was higher than that at the field at which the rate was greater at the harvest after late nov. compared to the earlier harvests. Although the two storages were similar at sound tuber rates and marketable yield, the tuber weight was more reduced when stored at room temperature than when done at cold temperature . Brightness and value 'b' of chromaticaity realted to the tuber coloring and sugar content were higher but moisture content was lowerwhen harvested on Oct. 15 than the other havesting dates. All the characteristics realted to the marketability after storage were nearly same when stored at room and cold temperature. Value 'a' of chromaticity and sugar content were higher when harvest on Mar. 15 than when harvested before Dec. 15 but the 'b' value and mositure content were reverse results.

• Progress in Superconductivity and Cryogenics
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• v.22 no.4
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• pp.45-50
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• 2020

In this research, the variation of round-trip efficiency in a liquid air energy storage system (LAES) is calculated and an optimal configuration is found. The multiple stages of cold energy storage are simulated with several materials that process latent heat at different temperature ranges. The effectiveness in the charging and discharging processes of LAES is newly defined, and its relationship with the round-trip efficiency is examined. According to defined correlation, the effectiveness of the discharging process significantly affects the overall system performance. The round-trip efficiency is calculated for the combined cold energy storage materials of aqueous dimethyl sulfoxide (DMSO) solution, ethanol, and pentane theoretically. The performance of LAES varies depending on the freezing point of the cold storage materials. In particular, when the LAES uses several cold storage materials, those materials whose freezing points are close to room temperature and liquid air temperature should be included in the cold storage materials. In this paper, it is assumed that only latent heat is used for cold energy storage, but for more realistic analyzes, the additional consideration of the transient thermal situation to utilize sensible heat is required. In the case of such a dynamic system, since there is certainly more increased heat capacity of the entire storage system, the volume of the cold energy storage system will be greatly reduced.

• The Korean Journal of Mycology
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• v.19 no.4
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• pp.292-298
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• 1991

Volatile aroma concentrates of Pleurotus sajor-caju which stored at $20^{\circ}C$ incubator and cold room were obtained by simultaneous distillation-extraction method. The volatile components were identified by combined capillary gas chromatography-mass spectrometry and comparison of retention data on GC of those authentic compounds. Storage at room temperature resulted in significant decreased in their total aroma contents, whereas little changes at cold storage foured, even though appreciable changes were observed in GC pattern between the control and stored samples. Of 38 components identified, ${\delta}-decalactone$ increased while rest of the volatiles decreased rapidly during storage at room temperature, but at cold storage 2-methyl butanal, 1-octen-3-ol, cis,cis-1,5-octadien-3-ol and pentadecanoic acid decreased while 3-octanone, 1-octen-3-one, 3-octanol and 5-undecanol increased with the storage time. The weight losses and organoleptic properties changed extremely by the storage under room temperature, on the other hand, slight changes were found in cold storage.